CA1300977C - Cam action compensator - Google Patents
Cam action compensatorInfo
- Publication number
- CA1300977C CA1300977C CA000536615A CA536615A CA1300977C CA 1300977 C CA1300977 C CA 1300977C CA 000536615 A CA000536615 A CA 000536615A CA 536615 A CA536615 A CA 536615A CA 1300977 C CA1300977 C CA 1300977C
- Authority
- CA
- Canada
- Prior art keywords
- casing
- housing
- tube
- fingers
- peristaltic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B43/00—Machines, pumps, or pumping installations having flexible working members
- F04B43/02—Machines, pumps, or pumping installations having flexible working members having plate-like flexible members, e.g. diaphragms
- F04B43/021—Machines, pumps, or pumping installations having flexible working members having plate-like flexible members, e.g. diaphragms the plate-like flexible member is pressed against a wall by a number of elements, each having an alternating movement in a direction perpendicular to the plane of the plate-like flexible member and each having its own driving mechanism
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
- A61M5/14—Infusion devices, e.g. infusing by gravity; Blood infusion; Accessories therefor
- A61M5/142—Pressure infusion, e.g. using pumps
- A61M5/14212—Pumping with an aspiration and an expulsion action
- A61M5/14228—Pumping with an aspiration and an expulsion action with linear peristaltic action, i.e. comprising at least three pressurising members or a helical member
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B43/00—Machines, pumps, or pumping installations having flexible working members
- F04B43/08—Machines, pumps, or pumping installations having flexible working members having tubular flexible members
- F04B43/082—Machines, pumps, or pumping installations having flexible working members having tubular flexible members the tubular flexible member being pressed against a wall by a number of elements, each having an alternating movement in a direction perpendicular to the axes of the tubular member and each having its own driving mechanism
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B43/00—Machines, pumps, or pumping installations having flexible working members
- F04B43/12—Machines, pumps, or pumping installations having flexible working members having peristaltic action
- F04B43/14—Machines, pumps, or pumping installations having flexible working members having peristaltic action having plate-like flexible members
Landscapes
- Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Biomedical Technology (AREA)
- Veterinary Medicine (AREA)
- Hematology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Heart & Thoracic Surgery (AREA)
- Anesthesiology (AREA)
- Vascular Medicine (AREA)
- Reciprocating Pumps (AREA)
- External Artificial Organs (AREA)
- Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
- Nozzles (AREA)
Abstract
ABSTRACT
A linear peristaltic device for pumping medical solutions to a patient comprises a hinged pivot or hinged attachment between the peristaltic drive mechanism and its associated platen. An IV tube, through which the medical solutions are to be pumped is received and held between the peristaltic drive mechanism and the platen during operation of the device. The device, also includes a compliant means which normally urges the peristaltic mechanism toward the platen but which yields, as necessary, to limit the force the peristaltic mechanism can exert against the tube.
A linear peristaltic device for pumping medical solutions to a patient comprises a hinged pivot or hinged attachment between the peristaltic drive mechanism and its associated platen. An IV tube, through which the medical solutions are to be pumped is received and held between the peristaltic drive mechanism and the platen during operation of the device. The device, also includes a compliant means which normally urges the peristaltic mechanism toward the platen but which yields, as necessary, to limit the force the peristaltic mechanism can exert against the tube.
Description
i3(~C)9'77 ~ACE;GROUND
2 The present invention relates generally to peristaltic 3 pumps which are used to pump fluids through resilient tubes.
4 More particularly, the present invention relates to the drive mechanism of a linear peristaltic pump and to the arrangement 6 for a mechanical compensator which minimizes the force that can 7 be exerted by the peristaltic mechanism against the tube. The 8 present invention is particularly, but not exclusively, useful 9 in the health care field for the intravenous administration of medical solutions to patients.
13 Various devices have been proposed which are specifically 14 and uniquely designed for the intravenous (IV) infusion of medical solutions to patients. Without exception, the 16 objective in each instance is to provide a device which can 17 reliably and accurately control the flow of fluid to the 8 patient. Typically, such devices are classified either as l9 pumps or controllers. The difference between the two being that a controller uses the effect of gravity to infuse fluids 21 to a patient while pumps generate a mechanical pressure on the 22 fluid for this purpose. The present invention is concerned 23 w i th pumps.
24 After having distinguished pumps from controllers, pumps can be further divided into categories depending on how the 26 particular pump exerts pressure on the infused fluid. Of the 13~)C~9';~7 l many types of pumps used for IV therapy, the present invention 2 is concerned with that type which exerts a peristaltic action 3 on the tube through which the fluid is being pumped. More 4 specifically, the present invention is concerned with pumps which fall generally into the category of linear peristaltic 6 pumps.
7 Although the actual design for a linear peristaltic pump 8 will differ from pump to pump, all such pumps require the 9 mechanical interaction of the following basic elements: a platen; a resilient tube through which fluid is to be pumped; a 11 peristaltic means (i.e. structure capable of creating a moving 12 zone of occlusion along the tube); and a drive mechanism for 13 the peristaltic means. For its operation, the linear 14 peristaltic pump must cause these elements to cooperate in a precise manner. Specifically, the peristaltic means must 16 operatively engage with the IV tubing through which the medical 17 solutions are to be pumped. As is well known by the skilled 18 artesan, this engagement requires placement of the tube between 19 the platen and the peristaltic means.
It should be apparent that for a moving zone of occlusion 21 to be generated along the tube, the pump must squeeze the tube 22 in some sequential manner. This squeezing action occurs as the 23 result of relative movement between the platen and the 24 peeistaltic means and this, in turn, generates forces between the components of the pump. Unless the device has properly ~6 engineered toleeances which are designed to relieve these 13~ 9'77 1 forces, the squeezing action can result in a seizure or 2 stoppage of the device. Obviously, such an occurrence is to be 3 avoided. On the other hand, the pump must be able to exert 4 sufficient forces on the tube to create the zone of occlusion. Consequently, there is a limited range of forces 6 which are acceptable for proper operation of the pump.
7 In addition to causing an actual seizure or stoppage of 8 the pump, forces generated during pump operation can also 9 create problems with the tube itself. Specifically, even though the pump may continue to operate, excessive occlusion or 11 pinching forces on the tube can cause both short-term and long-12 term deformations of the tube that will result in uncontrolled 13 variations in fluid flow through the tube. Also, excessive 14 occlusion forces can cause spalling of the tube with the potentially catastrophic infusion of particles to the 16 patient. Admittedly, some of the above stated problems can be 17 alleviated by the selection of proper tubing materials. Even 18 proper tube selection, however, does not completely eliminate 19 the problem.
As impliedly stated above, the mechanical problems with 21 peristaltic pumps stem from the close tolerances required 22 between its interactive parts for proper operation. These 23 problems are particularly pronounced since the tolerances tend 24 to back up into the movement. Thus, each pump will react and behave differently to the same problem.
13~ 97'7 l In order to visuali~e the nature of these problems, first 2 consider the sequence in which the interactive parts 3 cooperate. Starting at one end of the combination, there is 4 the platen. Then, in sequential order, there is the tube, the peristaltic means and the drive mechanism. To prevent seizure 6 of the mechanism, one or more of these elements must yield 7 whenever an excessive force is generated. Once a particular 8 tube is selected, specific predetermined dimensional 9 limitations are introduced into the combination. Thus, the tube itself cannot be expected to provide the necessary 11 resilience to obviate the problem. Indeed, rather than absorb 12 the excess forces with tube resiliency, the effort is more 13 properly focused on ways that limit the force exerted on the 14 tube. Consequently, design efforts have focused on the other elements in the device.
16 One way in which excessive forces in the peristaltic pump 17 can be alleviated is to allow the platen to yield. For 18 example, U.S. Patent No. 4,373,525 to ~oboyashi discloses a 19 linear peristaltic pump having a spring loaded platen. The same purpose is accomplished, but with dissimilar structure, by 21 the device of U.S. Patent No. 4,482,347 to Borsanyi which 22 discloses a resilient surface set into the face of the 23 platen. Both designs, however, have certain disadvantages.
24 First, consider the design incorporating a platen with a resilient surface. Such a design generally operates with a 26 distance between the peristaltic mechanism and the platen that 13~ 9~7 l varies according to the resilienc~ of the platen without regard 2 for the wall thickness of the tube. Thus, it happens that the 3 dimensional requirements to occlude a thin walled tube can 4 create problems when thicker walled tubes are used. Indeed, for a thicker walled tube, not only is greater force exerted on 6 the tubing but the portion of the tube that is occluded will be 7 increased. The greater force, of course, adds trauma to the 8 tube and the increased occlusion area reduces the fluid 9 volumetric flow. Both effects are unwanted.
Second, in the case of a spring-loaded or "floating"
11 platen it can be demonstrated that conventional designs of this 12 type generate a varying force at the point of tube occlusion.
13 This is dependent on where the occlusion occurs. To illustrate 14 this point, consider a platen supported at either end by a spring which exerts a force F against the platen. When the 16 occlusion occurs over a support point, the reactive force of 17 the peristaltic mechanism against the tube will equal F. On 18 the other hand, when the occlusion occurs at mid span, the 19 reactive force of the peristaltic mechanism against the tube will equal 2F. This unwanted variation in force on the tube 21 can create some of the problems previously discussed.
22 Excessive forces within the peristaltic pump can also be 23 alleviated by allowing the peristaltic mechanism to yield. If 24 this is done, the dimensional relationship between the drive mechanism for the peristaltic means and the platen can be 26 fixed. Within this fixed relationship the design compensates l for variations in tubing dimensions by making the peristaltic 2 mechanism compliant. Examples of such mechanisms include the 3 device disclosed in U.S. Patent No. 3,137,242 to Hahn in which 4 tension springs are used to engage the peristaltic rollers with the tube. Another example of a yielding or compliant 6 peristaltic mechanism is found in U.S. Patent No. 4,095,923 to 7 Cullis which teaches the use of yieldable rubber bushings 8 between peristaltic rollers and the driving axles. Still 9 another example of such a means is the design for a linear peristaltic pump in which individually resilient fingers are 11 operatively associated with a rotating cam shaft. The 12 shortcoming for these designs, however, is that each resilient 13 structure introduces its own variable into the operation of the 14 device.
The foregoing discussion leads to a consideration of the 16 possibility that two components, rather than one, should be 17 allowed to yield. For reasons previously stated, the tube 18 itself will be eliminated from this consideration. Also, it is 19 to be understood that the cyclical movement of the means causing the peristaltic action is not a yielding movement which 21 will alleviate an excessive force on the tube. This leaves the 22 platen, the entire peristaltic means and the drive motor for 23 consideration. First, consider the possibility of allowing 24 both the platen and the peristaltic means to yield. Since the tube is between these elements, they must yield independently 26 of each other. Not only is this a complex mechanical 13vog77 l arrangement, it can be very difficult to manufacture and even 2 more difficult to properly engineer for predictable and 3 reliable fluid flow. Further, the interaction of so many 4 independent variables makes linearization of the flow very hard, if not impossible, to accomplish. On the other hand, if 6 the entire peristaltic means and its associated drive mechanism 7 are combined and allowed to yield together relative to the 8 platen, the only variable which must be controlled is the 9 amount of force exerted by the peristaltic mechanism against the tube. The present invention recognizes that such an 11 arrangement can be constructed and done in a manner which 12 allows the combination to yield against the opposing effect of 13 a simple spring force.
14 In light of the above, the present invention addresses the many problems associated with linear peristaltic pumps which 16 are created by an inability to constrain the forces exerted on 17 the tube within an efficient range for a proper pumping 18 operation. Further, the present invention recognizes that 19 engineering tolerances can be critical for a peristaltic pump and that the difficulty in manufacturability increases 21 proportionately with this criticality.
22 Accordingly, it is an object of the present invention to 23 provide a peristaltic pumping device which minimizes trauma to 24 the tube during the pumping operation. Ancillary to this are the objectives of providing a peristaltic pump which reduces 26 the risk of spalling the tube and which extends the useful life ~3~C~977 ~ of the tube. Another objective of the present invention is to 2 reduce fluid volumetric flow errors which result when 3 variations in tubing wall thicknesses affect the size of the 4 occlusion zone. Still another object o~ the present invention s is to reduce power and consequently, torque requirements. Yet 6 another objective of the present invention is to provide a 7 linear peristaltic pump which is easy to manufacture and which 8 does not require extremely close tolerances between its 9 mechanical components for proper assembly. Another objective of the present invention is to provide a durable and reliable Il peristaltic pump which is cost effective and which accurately 12 infuses fluids to patients.
The preferred embodiment of the linear peristaltic hinged 16 cam action compensator of the present invention comprises 17 structure which provides for a yielding or compliant movement 18 between the platen and the drive mechanism. More specifically 19 the preferred embodiment of the present invention comprises a casing on which a rotatable shaft is mounted which has a 21 plurality of cams spaced therealong in a helical arrangement.
22 Operatively associated with each cam is a peristaltic finger.
23 A housing is hingedly attached to the casing with the 24 transverse axis of the hinge aligned substantially parallel to the longitudinal axis of the cam shaft. The housing itself is 26 formed as a rectangular box having no top or bottom. A series _g_ i3~0g77 l of grooves formed on the inner sur~ace of its sides are 2 1 established for respectively receiving the peristaltic 3 fingers. In its combination with the casing, the housing 4 serves as a guide for the peristaltic fingers and constrains them for reciprocal linear movement in accordance with the 6 action of the cam shaft on the fingers. A compliant means, 7 such as a spring, is attached between the casing and the 8 housing to urge rotation of the casing about the hinge axis 9 toward the housing in a manner which holds the peristaltic fingers in the grooved guides of the housing. Contrarily, the 11 compliant means tends against a rotation of the casing about 12 the hinge axis which would lift the fingers out of the 13 housing. The present invention further comprises a platen 14 which can be positioned into a fixed spacial relationship with respect to the housing to hold a resilient tube between the 16 platen and the peristaltic fingers during a rotation of the 17 shaft for a pumping operation.
18 In another embodiment of the present invention, the 19 connection between the housing and the casing is accomplished by an integral hinge formed at their juncture to establish a 21 pivotal movement therebetween. In still another embodiment of 22 the present invention the connection between the casing and the 23 housing can be accomplished by joining them together with a 24 flexure which obviates the need for a compliant or resistive 2S means.
13~)0g77 1 The novel features of this invention as well ~s the 2 invention itself both as to its organization and operation will 3 be best understood from the accompanying drawings taken in 4 conjunction with the accompanying description in which similar reference characters re~er to simlar parts and in which:
8 Figure l is a front elevational view of a linear 9 peristaltic pump incorporating the present invention shown in its working environment;
11 Figure 2 is a side elevational view of the pumping 12 mechanism of the present invention;
13 Figure 3 is a side cross-sectional view along the 14 centerline of the pumping mechanism of the present invention which corresponds to the view seen in Figure 2;
16 Figure 4 is an exploded perspective view of the pumping 17 mechanism with portions cut away for clarity;
18 Figure 5 is a cross-sectional view of the pumping 19 mechanism as seen along the line 5-5 in Figures 3 and 4;
Figure 6 is cross-sectional view of the pumping mechanism 21 as seen in Figure 5 when the mechanism is compensating for an 22 excessively thick walled tube;
23 Figure 7 is a cross-sectional view of the pumping 24 mechanism as seen along the line 7-7 in Figures 3 and 4;
13~ )9~7 l Figure 8 is a cross-sectional view of the pumping 2 mechanism for the embodiment comprising a flexure as seen along 3 the line 5-5 in Figures 3 and 4; and 4 Figure 9 is a cross-sectional view of the pumping mechanism comprising an integral hinge as seen along the line 6 7-7 in Figures 3 and 4.
9Referring initially to Figure 1, a set up of the present invention is shown in its intended environment. In Figure 1 a Il linear peristaltic pump generally designated 10 is shown 12 mounted onto an IV pole 12. A fluid source 14 is hung from IV
13 pole 12 in a manner well known in the art. IV tube 16 is 14 connected into fluid communication with the fluid source 14 and operatively engaged with the pumping mechanism 18 of linear 16 peristaltic pump 10. It is further shown in Figure 1 that IV
17 tube 16 entends from linear peristaltic pump 10 and is attached 18 to patient 20. Thus, as shown in Figure 1, it is intended that 19 a linear peristaltic pump 10 operatively engaged with an IV
tube 16 to pump fluid from a fluid source 14 through the I~
21tube 16 to a patient 20. Pumping mechanism 18 of linear 22 peristaltic pump 10 is shown by itself and separated from 23 linear peristaltic pump 10 in Figure 2.
24With reference to Figure 2, the general arrangement of the major components of the pumping mechanism 18 and their 26 interaction can been seen. ~pecifically, it is shown that 13()~9~7 I pumping mechanism 18 includes a casing 22, a housing 24, and a 2 drive motor 26, all of which are placed in operative 3 association with a platen 28. The actual specifics of the 4 cooperation of the structure of these components will be set forth in detail below. For the moment it suffices that drive 6 motor 26 is operatively associated with casing 22 for moving 7 peristaltic fingers 30 against IV tube 16 which is supported by platen 28.
9As is well known in the pertinent art, the action of 10peristaltic fingers 30 against IV tube 16 while tube 16 is 11 being held between peristaltic fingers 30 and the platen 28 12 creates a moving zone of occlusion along tube 16 which 13 effectively pumps fluid through tube 16 to patient 20. A more 14 detailed description of the components of pumping mechanism 18 of linear peristaltic pump 10 is best seen with reference to 16 Figure 3.
17In Figure 3 it can be seen that drive motor 26 is attached 8 to a bracket 32. As shown, this attachment is accomplished 9 through the use of screws, but it will be appreciated by those 0 skilled in the art that this attachment can be accomplished by 1 any number of ways so long as the attachment establishes a 2 fixed relationship between the drive motor 26 and b~acket 32.
3 Drive motor 26 is operatively connected with a drive shaft 34 4 to cause rotation of drive shaft 34. A sleeve 36 connects drive shaft 34 with cam shaft 38 so that the rotational motion 6 of drive shaft 34 is transferred through sleeve 36 to cam shaft 13~ '77 l 38. Casing 22 includes a bearing 40 and a bearing 42 which 2 support cam shaft 38 for rotation relative to casing 22 and 3 bracket 32 is fixedly attached to casing 22 in a manner which 4 holds drive motor 26, cam shaft 38 and casing 22 in the S relationship shown in Figure 3. Thus, it will be appreciated 6 that cam shaft 38 remains in the same position with respect to 7 casing 22 and that the rotation of cam shaft 38 about its 8 longitudinal axis can be accomplished without changing this 9 relationship.
Also seen in Figure 3, arranged along the length of cam 11 shaft 38, are a series of cams 44. As will be appreciated by 12 the skilled artesan, cams 44 are arranged lengthwise along cam 13 shaft 38 in a helical relationship. This arrangement of the 14 cams 44 along cam shaft 38, when operatively associated with peristaltic fingers 30, cause a sequential reciprocal motion of 16 the peristaltic fingers 3~ that results in a peristaltic action 17 of the fingers 30 against IV tube 16.
18 Also shown in Figure 3 is a membrane 46 which separates 19 the peristaltic fingers 30 from the IV tube 16. Incorporation of membrane 46 serves as a barrier to prevent the unwanted 21 entry of fluids from the IV tube 16 or fluid source 14 into the 22 internal working elements of pumping mechanism 18. Further, as 23 seen in Figure 3, pumping mechanism 18 of the present invention 24 is shown incorporating stationary members 48 and a pressure sensor 50. The inclusion of these elements into pumping 26 mechanism 18 are informational to show that the present 13~10~77 invention is compatible with the dual mode infusion devices set forth in U.S. Patent No. 4,617,014 and U.S. Patent No. 4,690,673 both of which are assigned to the same assignee as the present invention.
The cooperation of structure between casing 22 and housing 24 is perhaps best seen with reference to Figure 4. In the exploded view of pumping mechanism 18 shown in Figure 4, it is perhaps more apparent that cam shaft 38 has a set relationship with casing 22 for rotation about its longitudinal axis. Also, it is seen in Figure 4 that housing 24 is essentially a rectangular shaped structure having an open top and an open 12 bottom. The open bottom of housing 24 provides for the extension of peristaltic fingers 30 therethrough and the consequent operative engagement of peristaltic fingers 30 with is IV tube 16. The interior side walls 51 of housing 24 are formed with a series of grooves 52 which are arranged in side by side relationship and separated by guides 54. The grooves 52 are established for receiving the peristaltic fingers 30 therein and guides 54 are intended to maintain peristaltic fingers 30 within grooves 54 for linear reciprocal action therein. The exact purpose of this will become clear as the discussion of the present invention proceeds.
The attachment of casing 22 to housing 24 is accomplished by a hinged relationship. To accomplish this connection casing 22 is formed with hinge ear 56 which can be positioned next to hinge tab 58 on housing 24. A hinge pin 60 inserted into hole 13~0977 l 62 of hinge tab ~8 and extending therethrough and into hole 64 2 of hinge ear 56 establishes the hinged relationship between 3 casing 22 and housing 24. A second hinge point can also be 4 established. More specifically Figure 4 shows a hinge tab 78 S and hinge pin 80 which can be attached to a hinge ear (not 6 shown) on casing 22 in a manner similarly to that discussed for 7 the attachment of hinge ear 56 with hinge tab 58. It will be 8 understood by a person of ordinary skill in the art, that the 9 hinge mechansim as shown for the present invention in Figure 4 is only illustrative and that any arrangement whereby a hinged 11 action is established between casing 22 and housing 24 will 12 suffice for the present invention. Further, while one hinge 13 point may be sufficent for operation of the present invention, 14 a plurality of hinge points as disclosed herein are also appropriate.
16 In another embodiment of the present invention, casing 22 17 is pivotally connected with housing 24 by a flexure 102 as seen 18 in Figure 8. More specifically, flexure 102 is joined with 19 casing 22 in a rigid manner by any means well known in the art such as by an anchor means 104. Flexure 102 is also fixedly 2l joined with housing 24 by similar means. It is to be 22 understood that the material which comprises flexure 102 can be 23 selected in accordance with the bending requirements between 24 the casing 22 and housing 24. Stated differently, flexure 102 can be selected with a desired stiffness or spring constant to 26 suit the purposes of the present invention. As will be readily 13VI:)'3`77 } understood by the skilled artesan, such a flexure 102 at the 2 juncture of casing 22 and housing 24 creates a pivot axis 3 around which relative rotational motion between the casing 22 4 and housing 24 can be accomplished. Further, when a flexure 102 is used for purposes of joining casing 22 with housing 24 6 it is to be understood that the resilient means for resisting 7 rotation of casing 22 relative to housing 24 is no longer 8 required. Specifically, because of the stiffness inherent in 9 the flexure 102, spring 66 and spring 76 can be eliminated from the structure of the pump 10. In all important respects, the Il operation of pump 10, when a flexure 102 is incorporated into 12 its structure, is the same as for the perferred embodiment 13 incorporating the hinged attachment of casing 22 to housing 14 24. The actual interworking of these components of structure remain unchanged.
16 Figure 9, shows still another embodiment of the present 17 invention for pump 10 wherein the connection between casing 22 18 and housing 24 is accomplished by an integral hinge 106.
19 Integral hinge 106 is sometimes referred to by skilled artesans as a "living hinge~. More specifically, integral hinge 106 21 comprises a section of reduced cross-sectional area to allow a 22 rotational movement of casing 22 with respect to housing 24.
23 As will be understood by the person of ordinary skill in the 24 pertinent art, the incorporation of an integral hinge 106 allows casing 22, housing 24 and the in~egral hinge 106 to be 26 manufactured by an injection molding procedure. Further, it i3~)0~377 l will be understood by the person of ordinary skill in the 2 pertinent art that with the particular embodiment incorporating 3 an integral hinge 106, the spring 66 as disclosed elsewhere for 4 the present invention needs to be incorporated. In all s important respects, the pump lO which incorporates an integral 6 hinge 106 for connecting casing 22 with housing 24 functions in 7 an identical manner as disclosed for the preferred embodiment 8 of the present invention.
9 To further show the cooperation of casing 22 in its relationship with housing 24 reference is still made to Figure 11 4. There can be seen that in addition to the hinged 12 relationship between casing 22 and housing 24 previously 13 discussed, a spring 66 urges casing 22 toward housing 24 in a 14 predictable manner. To do this, spring 66 is attached to housing 24 at an attachment point 68 and further attached to 16 casing 22 at an attachment point 70. It is understood that the 17 attachment of spring 66 between housing 24 and casing 22 can be 18 accomplished by any manner well known in the art and, that 19 spring 66 is only illustrative of the various flexible structures which could accomplish the same purpose for the 21 present invention.
22 The interworking of the hinged attachment of casing 22 to 23 housing 24 and the counteracting spring attachment therebetween 24 is further seen by reference back to Figure 2 wherein spring 66 is shown as the attachment between casing 22 and housing 24 by 26 its respective connections with attachment point 70 and 1300~'77 la tachment point 68~ It is also shown in Figure 2 that a 2s cond spring 76 is attached to housing 24 and casing 22 3r spectively at attachment points 72 and 74.
4 Recall that casing 22 is hingedly attached to housing 24 sf r rotation about a transverse axis which is defined and 6e tablished by the hinged connections between casing 22 and 7h using 24 at hinge tabs 58 and 78. Also, recognize that the 8r tation of casing 22 relative to housing 24 about the gt ansverse action of the hinge is constrained by the attachment 10 springs 76 and 66 bring casing 22 into contact with housing 2 in a manner that maintains the positioning of peristaltic 2f ngers 30 within the respective grooves 52 of housing 24.
13 As shown in Figures 4 and 5, peristaltic finger 30 is 14P' sitioned within housing 24 for reciprocal movement along the l5gr oves 52 established by guides 54. The body 84 of ~e istaltic finger 30 is formed with a resilient arm 82 that ~e ts within the groove 52 to stabilize the lateral movement of ~e istaltic finger 30 within housing 24 without creating an 19in erference between peristaltic finger 30 and housing 24.
2~1 ' in Figure 5 it is seen that peristaltic finger 30 is 21f med with an extender 86 to establish a recess 88 within 22wh ch a cam 44 may be received. With this engagement, finger 233 moves linearly and reciprocally within housing 24 dependent 24P n the urging of cam 44 against extender 86 and body 84 of 2~P istaltic ~inger 30. Although the particular cross-sectional 26i w of pumping mechanism 18 as seen in Figure 5 does not show 13~)0~'77 1 the attachment of housing 24 with respect to platen 28, it is 2 to be understood that the platen 28 is brought into a fixed 3 dimensional relationship with respect to housing 24 during the 4 operation of linear peristaltic pump lO. For any particular s peristaltic pump lO it is only important that some mechanism 6 allows for such a fixed relationship between platen 28 and 7 pumping mechanism 18. As suggested in Figure 6 this can be 8 done through an actual fixed attachment between housing 24 and 9 platen 28 such as the use of connector 92 and attachment 94.
It is within the spirit of the present invention to recognize 11 that IV tube 16 needs only to be placed for operative 12 engagement between peristaltic fingers 30 and platen 28. Thus, 13 so long as the relationship between housing 24 and platen 28 14 can remain fixed, while relative motion with respect to platen 28 is accomplished by other components of pumping mechanism 18 t 16 the purposes of the present invention can be accomplished.
17 Reference is now made to Figure 7 to again appreciate that 18 casing 22 is hingedly mounted to the housing 24 for rotation 19 about a hinge pin 60. As will be appreciated by the skilled artesan, hinge pin 60 establishes the transverse axis for the 21 hinged connection between casing 22 and housing 24. Further, z2 as previously discussed, spring 66 resists rotation of casing 23 22 about housing 24 in the direction indicated by arrow 90.
24 With this cooperation of structure in mind, reference is 130~9~7 1 directed back to Figures S and 6 wherein it can be seen that 2 peristaltic finger 30 is mounted in housing 24 for reciprocal 3 motion in respect thereto.
4 The motion of peristaltic finger 30 with respect to housing 24 is accomplished in either or both of two wa~s.
6 First, the rotation of cam shaft 38 by drive motor 26 urges 7 cams 44 against peristaltic finger 30 to create a linear 8 reciprocal movement of peristaltic fingers 30. The second 9 manner in which peristaltic fingers 30 can be moved relative to housing 24 is in response to the movement of casing 22 with 11 respect to housing 24. Recall that cam shaft 38 is mounted 12 onto casing 22. Thus, any force which causes a aisplacement of 13 cam shaft 38 will also manifest itself as a movement of casing 14 22. Since casing 22 is constrained to rotate about the axis 98 established by hinge 60, this movement will be opposed by the 16 action of springs 66 and 76.
17 In order to appreciate the mechanism by which the peesent 18 invention brings force on the IV tube 16 to create a moving 19 zone occlusion therealong, consider an IV tube 16 having a specific wall thickness which creates a dimension between 21 platen 28 and peristaltic 30 equivalent to dimensional 22 indicator 96 shown in Figure 5. In accordance with the present 23 invention, when platen 28 is fixed relative to housing 24, 24 dimension 96 will be determined only by the action of peristaltic finger 30 against IV tube 16. Thus in a static i30~9`77 l condition of occlusion, the force that peristaltic finger 30 2 exterts against IV tube 16 will be a function of the dimension 3 96.
4 The importance of the dimensional interaction of pumping mechanism 18 with platen 28 is now best appreciated by cross 6 referencing Figure 5 with Figure 6.
7 As previously indicated, housing 24 is established in 8 fixed spatial relationship with respect to platen 28. When IV
9 tube 16 is supported by platen 28 for operative engagement with pumping mechanism 18, the distance 96 between edge 100 of 11 peristaltic finger 30 and platen 28 will be, in part, 12 determined by the characteristics of IV tube 16. During 13 operation, sufficient force neeas to be exterted by the 14 peristaltic finger 30 against IV tube 16 to cause a period.c occlusion. However, it is necessary to constrain or limit this 16 force so that the adverse effects of an excessive force against 1~ IV tube 16 are eliminated. In Figure 5 it can be seen that any 18 relief from the action of peristaltic finger 30 against IV tube 19 16 will be manifested through peristaltic finger 30 to cam 44 on cam shaft 38. Recall that cam shaft 38 is mounted for 21 rotation on casing 22. Therefore, any movement o cam shaft 38 22 caused by a backforce exerted from peristaltic 30 will be 23 transmitted to the casing 22 and, as discussed earlier with 24 respect to Figure 7, will result in a rotation of casing 22 about hinge axis 98 relative to the housing 24. The resistance 26 to such a rotation of casing 22 is caused by springs 66 and 13~)0~77 1 76. Therefore the resistive force encountered by the mechanism 2 can be established through proper selection of springs 66 and 3 76.
4 Figure 6 shows an IV tube 16' having thicker walls than IV
S tube 16 in Figure 5. This will correspondingly cause a change 6 in the distance 96 to 96'. As will be appreciated by the 7 skilled aretsan, this dimensional change manifests itself as a 8 force through peristaltic finger 30 against cam shaft 38.
9 This, in turn, causes cam shaft 38 and casing 22 to rotate about hinge axis 98. During such a rotation, it will be 11 appreciated that the relationship of cam shaft 38 with respect 12 to casing 22 remains unchanged. Thus, pump l0 will operate 13 equally well regardless whether cam shaft 38 and casing 22 are 14 oriented as shown in Figure 5 or as shown in Figure 6.
Consequently, the actual pumping operation of the linear 16 peristaltic pump l0 of the present invention is accomplished 17 independently of the wall thickness of tube 16.
In the operation of pump l0, IV tube 16 is positioned 21 between platen 28 and pumping mechanism 18. Cam shaft 38 is 22 mounted on casing 22 and drive motor 26 is operatively 23 connected to cam shaft 38 to cause its rotation. The 24 consequent action of cams 44 on cam shaft 38 causes a linear ~6 13~Qg~7 l reciprocal movement of the peristaltic fingers 30 within 2 grooves 52 of housing 24. This movement manifests itself as a 3 moving zone of occlusion against IV tube 16.
4 The forces created by peristaltic fingers 30 against IV
s tube 16 are limited by the interaction of casing 22 with 6 housing 24. Specifically, and regardless of the dimensions of 7 IV tube 16 being used in association with linear peristaltic 8 pump 10, the peristaltic fingers 30 are able to move into 9 contact with IV tube 16 only to the point that any further lo force exerted against a peristaltic finger 30 will cause a 11 movement between casing 22 and housing 24.
12 More specifically, any excessive backforce created on 13 peristaltic fingers 30 by variations in the dimensions of IV
14 tube 16 will be exerted against cam shaft 38 to rotate casing 22 about hinge axis 98 relative to housing 24. Resistance to 16 this rotational motion of casing 22 about hinge axis 98 is 17 caused by the action of springs 66 and 76 and their connections 18 between casing 22 and 24. Thus, it will be appreciated by the 19 skilled artesan that the peristaltic action of pumping mechanism 18 against IV tube 16 can be accomplished 21 independently of dimensional variables introduced by IV tube 16 22 and with equal efficiency for various IV tubes 16.
23 It is to be understood that the relative motion between 24 casing 22 and housing 24 about hinge axis 98 can be accomplished by various structures. Specifically, as disclosed 26 herein for the preferred embodiment, a hinge can be used.
13~g77 l Alternatively, a flexure 102 may be used to connect casing 22 2 with housing 24. In still anothee embodiment, an integral 3 hinge 106 can be incorporated for this purpose.
4 While the particular cam action compensator as herein shown and disclosed in detail is fully capable of obtaining the 6 objects and providing the advantages hereinbefore stated, it is 7 to be understood that it is merely illustrative of the 8 presently preferred embodiment of the invention and that no 9 limitations are intended to the details of construction or design herein shown other than as defined in the appended 11 claims.
æ
13 Various devices have been proposed which are specifically 14 and uniquely designed for the intravenous (IV) infusion of medical solutions to patients. Without exception, the 16 objective in each instance is to provide a device which can 17 reliably and accurately control the flow of fluid to the 8 patient. Typically, such devices are classified either as l9 pumps or controllers. The difference between the two being that a controller uses the effect of gravity to infuse fluids 21 to a patient while pumps generate a mechanical pressure on the 22 fluid for this purpose. The present invention is concerned 23 w i th pumps.
24 After having distinguished pumps from controllers, pumps can be further divided into categories depending on how the 26 particular pump exerts pressure on the infused fluid. Of the 13~)C~9';~7 l many types of pumps used for IV therapy, the present invention 2 is concerned with that type which exerts a peristaltic action 3 on the tube through which the fluid is being pumped. More 4 specifically, the present invention is concerned with pumps which fall generally into the category of linear peristaltic 6 pumps.
7 Although the actual design for a linear peristaltic pump 8 will differ from pump to pump, all such pumps require the 9 mechanical interaction of the following basic elements: a platen; a resilient tube through which fluid is to be pumped; a 11 peristaltic means (i.e. structure capable of creating a moving 12 zone of occlusion along the tube); and a drive mechanism for 13 the peristaltic means. For its operation, the linear 14 peristaltic pump must cause these elements to cooperate in a precise manner. Specifically, the peristaltic means must 16 operatively engage with the IV tubing through which the medical 17 solutions are to be pumped. As is well known by the skilled 18 artesan, this engagement requires placement of the tube between 19 the platen and the peristaltic means.
It should be apparent that for a moving zone of occlusion 21 to be generated along the tube, the pump must squeeze the tube 22 in some sequential manner. This squeezing action occurs as the 23 result of relative movement between the platen and the 24 peeistaltic means and this, in turn, generates forces between the components of the pump. Unless the device has properly ~6 engineered toleeances which are designed to relieve these 13~ 9'77 1 forces, the squeezing action can result in a seizure or 2 stoppage of the device. Obviously, such an occurrence is to be 3 avoided. On the other hand, the pump must be able to exert 4 sufficient forces on the tube to create the zone of occlusion. Consequently, there is a limited range of forces 6 which are acceptable for proper operation of the pump.
7 In addition to causing an actual seizure or stoppage of 8 the pump, forces generated during pump operation can also 9 create problems with the tube itself. Specifically, even though the pump may continue to operate, excessive occlusion or 11 pinching forces on the tube can cause both short-term and long-12 term deformations of the tube that will result in uncontrolled 13 variations in fluid flow through the tube. Also, excessive 14 occlusion forces can cause spalling of the tube with the potentially catastrophic infusion of particles to the 16 patient. Admittedly, some of the above stated problems can be 17 alleviated by the selection of proper tubing materials. Even 18 proper tube selection, however, does not completely eliminate 19 the problem.
As impliedly stated above, the mechanical problems with 21 peristaltic pumps stem from the close tolerances required 22 between its interactive parts for proper operation. These 23 problems are particularly pronounced since the tolerances tend 24 to back up into the movement. Thus, each pump will react and behave differently to the same problem.
13~ 97'7 l In order to visuali~e the nature of these problems, first 2 consider the sequence in which the interactive parts 3 cooperate. Starting at one end of the combination, there is 4 the platen. Then, in sequential order, there is the tube, the peristaltic means and the drive mechanism. To prevent seizure 6 of the mechanism, one or more of these elements must yield 7 whenever an excessive force is generated. Once a particular 8 tube is selected, specific predetermined dimensional 9 limitations are introduced into the combination. Thus, the tube itself cannot be expected to provide the necessary 11 resilience to obviate the problem. Indeed, rather than absorb 12 the excess forces with tube resiliency, the effort is more 13 properly focused on ways that limit the force exerted on the 14 tube. Consequently, design efforts have focused on the other elements in the device.
16 One way in which excessive forces in the peristaltic pump 17 can be alleviated is to allow the platen to yield. For 18 example, U.S. Patent No. 4,373,525 to ~oboyashi discloses a 19 linear peristaltic pump having a spring loaded platen. The same purpose is accomplished, but with dissimilar structure, by 21 the device of U.S. Patent No. 4,482,347 to Borsanyi which 22 discloses a resilient surface set into the face of the 23 platen. Both designs, however, have certain disadvantages.
24 First, consider the design incorporating a platen with a resilient surface. Such a design generally operates with a 26 distance between the peristaltic mechanism and the platen that 13~ 9~7 l varies according to the resilienc~ of the platen without regard 2 for the wall thickness of the tube. Thus, it happens that the 3 dimensional requirements to occlude a thin walled tube can 4 create problems when thicker walled tubes are used. Indeed, for a thicker walled tube, not only is greater force exerted on 6 the tubing but the portion of the tube that is occluded will be 7 increased. The greater force, of course, adds trauma to the 8 tube and the increased occlusion area reduces the fluid 9 volumetric flow. Both effects are unwanted.
Second, in the case of a spring-loaded or "floating"
11 platen it can be demonstrated that conventional designs of this 12 type generate a varying force at the point of tube occlusion.
13 This is dependent on where the occlusion occurs. To illustrate 14 this point, consider a platen supported at either end by a spring which exerts a force F against the platen. When the 16 occlusion occurs over a support point, the reactive force of 17 the peristaltic mechanism against the tube will equal F. On 18 the other hand, when the occlusion occurs at mid span, the 19 reactive force of the peristaltic mechanism against the tube will equal 2F. This unwanted variation in force on the tube 21 can create some of the problems previously discussed.
22 Excessive forces within the peristaltic pump can also be 23 alleviated by allowing the peristaltic mechanism to yield. If 24 this is done, the dimensional relationship between the drive mechanism for the peristaltic means and the platen can be 26 fixed. Within this fixed relationship the design compensates l for variations in tubing dimensions by making the peristaltic 2 mechanism compliant. Examples of such mechanisms include the 3 device disclosed in U.S. Patent No. 3,137,242 to Hahn in which 4 tension springs are used to engage the peristaltic rollers with the tube. Another example of a yielding or compliant 6 peristaltic mechanism is found in U.S. Patent No. 4,095,923 to 7 Cullis which teaches the use of yieldable rubber bushings 8 between peristaltic rollers and the driving axles. Still 9 another example of such a means is the design for a linear peristaltic pump in which individually resilient fingers are 11 operatively associated with a rotating cam shaft. The 12 shortcoming for these designs, however, is that each resilient 13 structure introduces its own variable into the operation of the 14 device.
The foregoing discussion leads to a consideration of the 16 possibility that two components, rather than one, should be 17 allowed to yield. For reasons previously stated, the tube 18 itself will be eliminated from this consideration. Also, it is 19 to be understood that the cyclical movement of the means causing the peristaltic action is not a yielding movement which 21 will alleviate an excessive force on the tube. This leaves the 22 platen, the entire peristaltic means and the drive motor for 23 consideration. First, consider the possibility of allowing 24 both the platen and the peristaltic means to yield. Since the tube is between these elements, they must yield independently 26 of each other. Not only is this a complex mechanical 13vog77 l arrangement, it can be very difficult to manufacture and even 2 more difficult to properly engineer for predictable and 3 reliable fluid flow. Further, the interaction of so many 4 independent variables makes linearization of the flow very hard, if not impossible, to accomplish. On the other hand, if 6 the entire peristaltic means and its associated drive mechanism 7 are combined and allowed to yield together relative to the 8 platen, the only variable which must be controlled is the 9 amount of force exerted by the peristaltic mechanism against the tube. The present invention recognizes that such an 11 arrangement can be constructed and done in a manner which 12 allows the combination to yield against the opposing effect of 13 a simple spring force.
14 In light of the above, the present invention addresses the many problems associated with linear peristaltic pumps which 16 are created by an inability to constrain the forces exerted on 17 the tube within an efficient range for a proper pumping 18 operation. Further, the present invention recognizes that 19 engineering tolerances can be critical for a peristaltic pump and that the difficulty in manufacturability increases 21 proportionately with this criticality.
22 Accordingly, it is an object of the present invention to 23 provide a peristaltic pumping device which minimizes trauma to 24 the tube during the pumping operation. Ancillary to this are the objectives of providing a peristaltic pump which reduces 26 the risk of spalling the tube and which extends the useful life ~3~C~977 ~ of the tube. Another objective of the present invention is to 2 reduce fluid volumetric flow errors which result when 3 variations in tubing wall thicknesses affect the size of the 4 occlusion zone. Still another object o~ the present invention s is to reduce power and consequently, torque requirements. Yet 6 another objective of the present invention is to provide a 7 linear peristaltic pump which is easy to manufacture and which 8 does not require extremely close tolerances between its 9 mechanical components for proper assembly. Another objective of the present invention is to provide a durable and reliable Il peristaltic pump which is cost effective and which accurately 12 infuses fluids to patients.
The preferred embodiment of the linear peristaltic hinged 16 cam action compensator of the present invention comprises 17 structure which provides for a yielding or compliant movement 18 between the platen and the drive mechanism. More specifically 19 the preferred embodiment of the present invention comprises a casing on which a rotatable shaft is mounted which has a 21 plurality of cams spaced therealong in a helical arrangement.
22 Operatively associated with each cam is a peristaltic finger.
23 A housing is hingedly attached to the casing with the 24 transverse axis of the hinge aligned substantially parallel to the longitudinal axis of the cam shaft. The housing itself is 26 formed as a rectangular box having no top or bottom. A series _g_ i3~0g77 l of grooves formed on the inner sur~ace of its sides are 2 1 established for respectively receiving the peristaltic 3 fingers. In its combination with the casing, the housing 4 serves as a guide for the peristaltic fingers and constrains them for reciprocal linear movement in accordance with the 6 action of the cam shaft on the fingers. A compliant means, 7 such as a spring, is attached between the casing and the 8 housing to urge rotation of the casing about the hinge axis 9 toward the housing in a manner which holds the peristaltic fingers in the grooved guides of the housing. Contrarily, the 11 compliant means tends against a rotation of the casing about 12 the hinge axis which would lift the fingers out of the 13 housing. The present invention further comprises a platen 14 which can be positioned into a fixed spacial relationship with respect to the housing to hold a resilient tube between the 16 platen and the peristaltic fingers during a rotation of the 17 shaft for a pumping operation.
18 In another embodiment of the present invention, the 19 connection between the housing and the casing is accomplished by an integral hinge formed at their juncture to establish a 21 pivotal movement therebetween. In still another embodiment of 22 the present invention the connection between the casing and the 23 housing can be accomplished by joining them together with a 24 flexure which obviates the need for a compliant or resistive 2S means.
13~)0g77 1 The novel features of this invention as well ~s the 2 invention itself both as to its organization and operation will 3 be best understood from the accompanying drawings taken in 4 conjunction with the accompanying description in which similar reference characters re~er to simlar parts and in which:
8 Figure l is a front elevational view of a linear 9 peristaltic pump incorporating the present invention shown in its working environment;
11 Figure 2 is a side elevational view of the pumping 12 mechanism of the present invention;
13 Figure 3 is a side cross-sectional view along the 14 centerline of the pumping mechanism of the present invention which corresponds to the view seen in Figure 2;
16 Figure 4 is an exploded perspective view of the pumping 17 mechanism with portions cut away for clarity;
18 Figure 5 is a cross-sectional view of the pumping 19 mechanism as seen along the line 5-5 in Figures 3 and 4;
Figure 6 is cross-sectional view of the pumping mechanism 21 as seen in Figure 5 when the mechanism is compensating for an 22 excessively thick walled tube;
23 Figure 7 is a cross-sectional view of the pumping 24 mechanism as seen along the line 7-7 in Figures 3 and 4;
13~ )9~7 l Figure 8 is a cross-sectional view of the pumping 2 mechanism for the embodiment comprising a flexure as seen along 3 the line 5-5 in Figures 3 and 4; and 4 Figure 9 is a cross-sectional view of the pumping mechanism comprising an integral hinge as seen along the line 6 7-7 in Figures 3 and 4.
9Referring initially to Figure 1, a set up of the present invention is shown in its intended environment. In Figure 1 a Il linear peristaltic pump generally designated 10 is shown 12 mounted onto an IV pole 12. A fluid source 14 is hung from IV
13 pole 12 in a manner well known in the art. IV tube 16 is 14 connected into fluid communication with the fluid source 14 and operatively engaged with the pumping mechanism 18 of linear 16 peristaltic pump 10. It is further shown in Figure 1 that IV
17 tube 16 entends from linear peristaltic pump 10 and is attached 18 to patient 20. Thus, as shown in Figure 1, it is intended that 19 a linear peristaltic pump 10 operatively engaged with an IV
tube 16 to pump fluid from a fluid source 14 through the I~
21tube 16 to a patient 20. Pumping mechanism 18 of linear 22 peristaltic pump 10 is shown by itself and separated from 23 linear peristaltic pump 10 in Figure 2.
24With reference to Figure 2, the general arrangement of the major components of the pumping mechanism 18 and their 26 interaction can been seen. ~pecifically, it is shown that 13()~9~7 I pumping mechanism 18 includes a casing 22, a housing 24, and a 2 drive motor 26, all of which are placed in operative 3 association with a platen 28. The actual specifics of the 4 cooperation of the structure of these components will be set forth in detail below. For the moment it suffices that drive 6 motor 26 is operatively associated with casing 22 for moving 7 peristaltic fingers 30 against IV tube 16 which is supported by platen 28.
9As is well known in the pertinent art, the action of 10peristaltic fingers 30 against IV tube 16 while tube 16 is 11 being held between peristaltic fingers 30 and the platen 28 12 creates a moving zone of occlusion along tube 16 which 13 effectively pumps fluid through tube 16 to patient 20. A more 14 detailed description of the components of pumping mechanism 18 of linear peristaltic pump 10 is best seen with reference to 16 Figure 3.
17In Figure 3 it can be seen that drive motor 26 is attached 8 to a bracket 32. As shown, this attachment is accomplished 9 through the use of screws, but it will be appreciated by those 0 skilled in the art that this attachment can be accomplished by 1 any number of ways so long as the attachment establishes a 2 fixed relationship between the drive motor 26 and b~acket 32.
3 Drive motor 26 is operatively connected with a drive shaft 34 4 to cause rotation of drive shaft 34. A sleeve 36 connects drive shaft 34 with cam shaft 38 so that the rotational motion 6 of drive shaft 34 is transferred through sleeve 36 to cam shaft 13~ '77 l 38. Casing 22 includes a bearing 40 and a bearing 42 which 2 support cam shaft 38 for rotation relative to casing 22 and 3 bracket 32 is fixedly attached to casing 22 in a manner which 4 holds drive motor 26, cam shaft 38 and casing 22 in the S relationship shown in Figure 3. Thus, it will be appreciated 6 that cam shaft 38 remains in the same position with respect to 7 casing 22 and that the rotation of cam shaft 38 about its 8 longitudinal axis can be accomplished without changing this 9 relationship.
Also seen in Figure 3, arranged along the length of cam 11 shaft 38, are a series of cams 44. As will be appreciated by 12 the skilled artesan, cams 44 are arranged lengthwise along cam 13 shaft 38 in a helical relationship. This arrangement of the 14 cams 44 along cam shaft 38, when operatively associated with peristaltic fingers 30, cause a sequential reciprocal motion of 16 the peristaltic fingers 3~ that results in a peristaltic action 17 of the fingers 30 against IV tube 16.
18 Also shown in Figure 3 is a membrane 46 which separates 19 the peristaltic fingers 30 from the IV tube 16. Incorporation of membrane 46 serves as a barrier to prevent the unwanted 21 entry of fluids from the IV tube 16 or fluid source 14 into the 22 internal working elements of pumping mechanism 18. Further, as 23 seen in Figure 3, pumping mechanism 18 of the present invention 24 is shown incorporating stationary members 48 and a pressure sensor 50. The inclusion of these elements into pumping 26 mechanism 18 are informational to show that the present 13~10~77 invention is compatible with the dual mode infusion devices set forth in U.S. Patent No. 4,617,014 and U.S. Patent No. 4,690,673 both of which are assigned to the same assignee as the present invention.
The cooperation of structure between casing 22 and housing 24 is perhaps best seen with reference to Figure 4. In the exploded view of pumping mechanism 18 shown in Figure 4, it is perhaps more apparent that cam shaft 38 has a set relationship with casing 22 for rotation about its longitudinal axis. Also, it is seen in Figure 4 that housing 24 is essentially a rectangular shaped structure having an open top and an open 12 bottom. The open bottom of housing 24 provides for the extension of peristaltic fingers 30 therethrough and the consequent operative engagement of peristaltic fingers 30 with is IV tube 16. The interior side walls 51 of housing 24 are formed with a series of grooves 52 which are arranged in side by side relationship and separated by guides 54. The grooves 52 are established for receiving the peristaltic fingers 30 therein and guides 54 are intended to maintain peristaltic fingers 30 within grooves 54 for linear reciprocal action therein. The exact purpose of this will become clear as the discussion of the present invention proceeds.
The attachment of casing 22 to housing 24 is accomplished by a hinged relationship. To accomplish this connection casing 22 is formed with hinge ear 56 which can be positioned next to hinge tab 58 on housing 24. A hinge pin 60 inserted into hole 13~0977 l 62 of hinge tab ~8 and extending therethrough and into hole 64 2 of hinge ear 56 establishes the hinged relationship between 3 casing 22 and housing 24. A second hinge point can also be 4 established. More specifically Figure 4 shows a hinge tab 78 S and hinge pin 80 which can be attached to a hinge ear (not 6 shown) on casing 22 in a manner similarly to that discussed for 7 the attachment of hinge ear 56 with hinge tab 58. It will be 8 understood by a person of ordinary skill in the art, that the 9 hinge mechansim as shown for the present invention in Figure 4 is only illustrative and that any arrangement whereby a hinged 11 action is established between casing 22 and housing 24 will 12 suffice for the present invention. Further, while one hinge 13 point may be sufficent for operation of the present invention, 14 a plurality of hinge points as disclosed herein are also appropriate.
16 In another embodiment of the present invention, casing 22 17 is pivotally connected with housing 24 by a flexure 102 as seen 18 in Figure 8. More specifically, flexure 102 is joined with 19 casing 22 in a rigid manner by any means well known in the art such as by an anchor means 104. Flexure 102 is also fixedly 2l joined with housing 24 by similar means. It is to be 22 understood that the material which comprises flexure 102 can be 23 selected in accordance with the bending requirements between 24 the casing 22 and housing 24. Stated differently, flexure 102 can be selected with a desired stiffness or spring constant to 26 suit the purposes of the present invention. As will be readily 13VI:)'3`77 } understood by the skilled artesan, such a flexure 102 at the 2 juncture of casing 22 and housing 24 creates a pivot axis 3 around which relative rotational motion between the casing 22 4 and housing 24 can be accomplished. Further, when a flexure 102 is used for purposes of joining casing 22 with housing 24 6 it is to be understood that the resilient means for resisting 7 rotation of casing 22 relative to housing 24 is no longer 8 required. Specifically, because of the stiffness inherent in 9 the flexure 102, spring 66 and spring 76 can be eliminated from the structure of the pump 10. In all important respects, the Il operation of pump 10, when a flexure 102 is incorporated into 12 its structure, is the same as for the perferred embodiment 13 incorporating the hinged attachment of casing 22 to housing 14 24. The actual interworking of these components of structure remain unchanged.
16 Figure 9, shows still another embodiment of the present 17 invention for pump 10 wherein the connection between casing 22 18 and housing 24 is accomplished by an integral hinge 106.
19 Integral hinge 106 is sometimes referred to by skilled artesans as a "living hinge~. More specifically, integral hinge 106 21 comprises a section of reduced cross-sectional area to allow a 22 rotational movement of casing 22 with respect to housing 24.
23 As will be understood by the person of ordinary skill in the 24 pertinent art, the incorporation of an integral hinge 106 allows casing 22, housing 24 and the in~egral hinge 106 to be 26 manufactured by an injection molding procedure. Further, it i3~)0~377 l will be understood by the person of ordinary skill in the 2 pertinent art that with the particular embodiment incorporating 3 an integral hinge 106, the spring 66 as disclosed elsewhere for 4 the present invention needs to be incorporated. In all s important respects, the pump lO which incorporates an integral 6 hinge 106 for connecting casing 22 with housing 24 functions in 7 an identical manner as disclosed for the preferred embodiment 8 of the present invention.
9 To further show the cooperation of casing 22 in its relationship with housing 24 reference is still made to Figure 11 4. There can be seen that in addition to the hinged 12 relationship between casing 22 and housing 24 previously 13 discussed, a spring 66 urges casing 22 toward housing 24 in a 14 predictable manner. To do this, spring 66 is attached to housing 24 at an attachment point 68 and further attached to 16 casing 22 at an attachment point 70. It is understood that the 17 attachment of spring 66 between housing 24 and casing 22 can be 18 accomplished by any manner well known in the art and, that 19 spring 66 is only illustrative of the various flexible structures which could accomplish the same purpose for the 21 present invention.
22 The interworking of the hinged attachment of casing 22 to 23 housing 24 and the counteracting spring attachment therebetween 24 is further seen by reference back to Figure 2 wherein spring 66 is shown as the attachment between casing 22 and housing 24 by 26 its respective connections with attachment point 70 and 1300~'77 la tachment point 68~ It is also shown in Figure 2 that a 2s cond spring 76 is attached to housing 24 and casing 22 3r spectively at attachment points 72 and 74.
4 Recall that casing 22 is hingedly attached to housing 24 sf r rotation about a transverse axis which is defined and 6e tablished by the hinged connections between casing 22 and 7h using 24 at hinge tabs 58 and 78. Also, recognize that the 8r tation of casing 22 relative to housing 24 about the gt ansverse action of the hinge is constrained by the attachment 10 springs 76 and 66 bring casing 22 into contact with housing 2 in a manner that maintains the positioning of peristaltic 2f ngers 30 within the respective grooves 52 of housing 24.
13 As shown in Figures 4 and 5, peristaltic finger 30 is 14P' sitioned within housing 24 for reciprocal movement along the l5gr oves 52 established by guides 54. The body 84 of ~e istaltic finger 30 is formed with a resilient arm 82 that ~e ts within the groove 52 to stabilize the lateral movement of ~e istaltic finger 30 within housing 24 without creating an 19in erference between peristaltic finger 30 and housing 24.
2~1 ' in Figure 5 it is seen that peristaltic finger 30 is 21f med with an extender 86 to establish a recess 88 within 22wh ch a cam 44 may be received. With this engagement, finger 233 moves linearly and reciprocally within housing 24 dependent 24P n the urging of cam 44 against extender 86 and body 84 of 2~P istaltic ~inger 30. Although the particular cross-sectional 26i w of pumping mechanism 18 as seen in Figure 5 does not show 13~)0~'77 1 the attachment of housing 24 with respect to platen 28, it is 2 to be understood that the platen 28 is brought into a fixed 3 dimensional relationship with respect to housing 24 during the 4 operation of linear peristaltic pump lO. For any particular s peristaltic pump lO it is only important that some mechanism 6 allows for such a fixed relationship between platen 28 and 7 pumping mechanism 18. As suggested in Figure 6 this can be 8 done through an actual fixed attachment between housing 24 and 9 platen 28 such as the use of connector 92 and attachment 94.
It is within the spirit of the present invention to recognize 11 that IV tube 16 needs only to be placed for operative 12 engagement between peristaltic fingers 30 and platen 28. Thus, 13 so long as the relationship between housing 24 and platen 28 14 can remain fixed, while relative motion with respect to platen 28 is accomplished by other components of pumping mechanism 18 t 16 the purposes of the present invention can be accomplished.
17 Reference is now made to Figure 7 to again appreciate that 18 casing 22 is hingedly mounted to the housing 24 for rotation 19 about a hinge pin 60. As will be appreciated by the skilled artesan, hinge pin 60 establishes the transverse axis for the 21 hinged connection between casing 22 and housing 24. Further, z2 as previously discussed, spring 66 resists rotation of casing 23 22 about housing 24 in the direction indicated by arrow 90.
24 With this cooperation of structure in mind, reference is 130~9~7 1 directed back to Figures S and 6 wherein it can be seen that 2 peristaltic finger 30 is mounted in housing 24 for reciprocal 3 motion in respect thereto.
4 The motion of peristaltic finger 30 with respect to housing 24 is accomplished in either or both of two wa~s.
6 First, the rotation of cam shaft 38 by drive motor 26 urges 7 cams 44 against peristaltic finger 30 to create a linear 8 reciprocal movement of peristaltic fingers 30. The second 9 manner in which peristaltic fingers 30 can be moved relative to housing 24 is in response to the movement of casing 22 with 11 respect to housing 24. Recall that cam shaft 38 is mounted 12 onto casing 22. Thus, any force which causes a aisplacement of 13 cam shaft 38 will also manifest itself as a movement of casing 14 22. Since casing 22 is constrained to rotate about the axis 98 established by hinge 60, this movement will be opposed by the 16 action of springs 66 and 76.
17 In order to appreciate the mechanism by which the peesent 18 invention brings force on the IV tube 16 to create a moving 19 zone occlusion therealong, consider an IV tube 16 having a specific wall thickness which creates a dimension between 21 platen 28 and peristaltic 30 equivalent to dimensional 22 indicator 96 shown in Figure 5. In accordance with the present 23 invention, when platen 28 is fixed relative to housing 24, 24 dimension 96 will be determined only by the action of peristaltic finger 30 against IV tube 16. Thus in a static i30~9`77 l condition of occlusion, the force that peristaltic finger 30 2 exterts against IV tube 16 will be a function of the dimension 3 96.
4 The importance of the dimensional interaction of pumping mechanism 18 with platen 28 is now best appreciated by cross 6 referencing Figure 5 with Figure 6.
7 As previously indicated, housing 24 is established in 8 fixed spatial relationship with respect to platen 28. When IV
9 tube 16 is supported by platen 28 for operative engagement with pumping mechanism 18, the distance 96 between edge 100 of 11 peristaltic finger 30 and platen 28 will be, in part, 12 determined by the characteristics of IV tube 16. During 13 operation, sufficient force neeas to be exterted by the 14 peristaltic finger 30 against IV tube 16 to cause a period.c occlusion. However, it is necessary to constrain or limit this 16 force so that the adverse effects of an excessive force against 1~ IV tube 16 are eliminated. In Figure 5 it can be seen that any 18 relief from the action of peristaltic finger 30 against IV tube 19 16 will be manifested through peristaltic finger 30 to cam 44 on cam shaft 38. Recall that cam shaft 38 is mounted for 21 rotation on casing 22. Therefore, any movement o cam shaft 38 22 caused by a backforce exerted from peristaltic 30 will be 23 transmitted to the casing 22 and, as discussed earlier with 24 respect to Figure 7, will result in a rotation of casing 22 about hinge axis 98 relative to the housing 24. The resistance 26 to such a rotation of casing 22 is caused by springs 66 and 13~)0~77 1 76. Therefore the resistive force encountered by the mechanism 2 can be established through proper selection of springs 66 and 3 76.
4 Figure 6 shows an IV tube 16' having thicker walls than IV
S tube 16 in Figure 5. This will correspondingly cause a change 6 in the distance 96 to 96'. As will be appreciated by the 7 skilled aretsan, this dimensional change manifests itself as a 8 force through peristaltic finger 30 against cam shaft 38.
9 This, in turn, causes cam shaft 38 and casing 22 to rotate about hinge axis 98. During such a rotation, it will be 11 appreciated that the relationship of cam shaft 38 with respect 12 to casing 22 remains unchanged. Thus, pump l0 will operate 13 equally well regardless whether cam shaft 38 and casing 22 are 14 oriented as shown in Figure 5 or as shown in Figure 6.
Consequently, the actual pumping operation of the linear 16 peristaltic pump l0 of the present invention is accomplished 17 independently of the wall thickness of tube 16.
In the operation of pump l0, IV tube 16 is positioned 21 between platen 28 and pumping mechanism 18. Cam shaft 38 is 22 mounted on casing 22 and drive motor 26 is operatively 23 connected to cam shaft 38 to cause its rotation. The 24 consequent action of cams 44 on cam shaft 38 causes a linear ~6 13~Qg~7 l reciprocal movement of the peristaltic fingers 30 within 2 grooves 52 of housing 24. This movement manifests itself as a 3 moving zone of occlusion against IV tube 16.
4 The forces created by peristaltic fingers 30 against IV
s tube 16 are limited by the interaction of casing 22 with 6 housing 24. Specifically, and regardless of the dimensions of 7 IV tube 16 being used in association with linear peristaltic 8 pump 10, the peristaltic fingers 30 are able to move into 9 contact with IV tube 16 only to the point that any further lo force exerted against a peristaltic finger 30 will cause a 11 movement between casing 22 and housing 24.
12 More specifically, any excessive backforce created on 13 peristaltic fingers 30 by variations in the dimensions of IV
14 tube 16 will be exerted against cam shaft 38 to rotate casing 22 about hinge axis 98 relative to housing 24. Resistance to 16 this rotational motion of casing 22 about hinge axis 98 is 17 caused by the action of springs 66 and 76 and their connections 18 between casing 22 and 24. Thus, it will be appreciated by the 19 skilled artesan that the peristaltic action of pumping mechanism 18 against IV tube 16 can be accomplished 21 independently of dimensional variables introduced by IV tube 16 22 and with equal efficiency for various IV tubes 16.
23 It is to be understood that the relative motion between 24 casing 22 and housing 24 about hinge axis 98 can be accomplished by various structures. Specifically, as disclosed 26 herein for the preferred embodiment, a hinge can be used.
13~g77 l Alternatively, a flexure 102 may be used to connect casing 22 2 with housing 24. In still anothee embodiment, an integral 3 hinge 106 can be incorporated for this purpose.
4 While the particular cam action compensator as herein shown and disclosed in detail is fully capable of obtaining the 6 objects and providing the advantages hereinbefore stated, it is 7 to be understood that it is merely illustrative of the 8 presently preferred embodiment of the invention and that no 9 limitations are intended to the details of construction or design herein shown other than as defined in the appended 11 claims.
æ
Claims (30)
1. An apparatus for pumping fluids through a tube which comprises:
a base for supporting said tube in a substantially linear orientation;
means for generating a peristaltic action on said tube;
and a flexure connecting said base with said peristaltic means for pivotal movement of said peristaltic means between a first position and a second position about an axis substantially parallel to the longitudinal axis of said tube, said flexure biased to yieldably urge said peristaltic means toward said first position and against said base for operative engagement of said peristaltic means with said tube.
a base for supporting said tube in a substantially linear orientation;
means for generating a peristaltic action on said tube;
and a flexure connecting said base with said peristaltic means for pivotal movement of said peristaltic means between a first position and a second position about an axis substantially parallel to the longitudinal axis of said tube, said flexure biased to yieldably urge said peristaltic means toward said first position and against said base for operative engagement of said peristaltic means with said tube.
2. An apparatus as recited in claim 1 wherein said peristaltic means comprises:
a cam shaft having a plurality of cams spaced in a helical relationship therealong; and a plurality of fingers operatively connected with said cams.
a cam shaft having a plurality of cams spaced in a helical relationship therealong; and a plurality of fingers operatively connected with said cams.
3. An apparatus as recited in claim 2 further comprising a casing for operatively mounting said cam shaft thereon.
4. An apparatus as recited in claim 3 further comprising a housing fixedly associated with said base, said housing having a plurality of grooves for receiving said fingers therein to constrain said fingers for linear reciprocal movement
5. An apparatus as recited in claim 4 wherein said base comprises a platen.
6. A linear peristaltic pump for pumping fluids through an IV tube having a cam action compensator which comprising:
a platen mounted on said pump;
a housing fixedly attached to said pump to receive said tube between said housing and said platen;
a plurality of fingers slidably mounted on said housing to squeeze said tube between said fingers and said platen to create a moving zone of occlusion along said tube;
a cam shaft operatively coupled to said fingers;
a casing having said cam shaft rotatably mounted thereon;
and a flexure connecting said casing to said housing for rotation of said casing between a first position and a second position about an axis substantially parallel to the longitudinal axis of said tube and for urging said casing toward said first position to compensate for the action between said fingers and said platen.
a platen mounted on said pump;
a housing fixedly attached to said pump to receive said tube between said housing and said platen;
a plurality of fingers slidably mounted on said housing to squeeze said tube between said fingers and said platen to create a moving zone of occlusion along said tube;
a cam shaft operatively coupled to said fingers;
a casing having said cam shaft rotatably mounted thereon;
and a flexure connecting said casing to said housing for rotation of said casing between a first position and a second position about an axis substantially parallel to the longitudinal axis of said tube and for urging said casing toward said first position to compensate for the action between said fingers and said platen.
7. A peristaltic pump as recited in claim 6 wherein said cam shaft has a plurality of cams mounted in a helical relationship therealong.
8. A peristaltic pump as recited in claim 7 wherein said fingers are formed with resilient arms to compensate for rotational motion of said fingers within said housing.
9. A peristaltic pump as recited in claim 8 further comprising a motor operatively connected with said cam shaft.
10. A linear peristaltic cam action compensator which comprises:
a casing;
a rotatable cam shaft operatively mounted on said casing;
a plurality of fingers coupled to said cam shaft;
a flexure; and a housing for operatively receiving said fingers, said housing yieldably connected to said casing by said flexure to establish a pivot axis substantially parallel to the longitudinal axis of said cam shaft for movement of said casing between a first position and a second position and for urging said casing toward said first position to resist movement of said casing about said axis.
a casing;
a rotatable cam shaft operatively mounted on said casing;
a plurality of fingers coupled to said cam shaft;
a flexure; and a housing for operatively receiving said fingers, said housing yieldably connected to said casing by said flexure to establish a pivot axis substantially parallel to the longitudinal axis of said cam shaft for movement of said casing between a first position and a second position and for urging said casing toward said first position to resist movement of said casing about said axis.
11. A compensator as recited in claim 10 further comprising a resilient tube; and a platen operatively associated with said housing to hold said tube therebetween.
12. A compensator as recited in claim 11 wherein said fingers are formed with resilient arms to ensure linear movement of said fingers relative to said housing.
13. An apparatus for pumping fluids through a tube which comprises:
a base for supporting said tube in a substantially linear orientation;
peristaltic means for generating a moving zone of occlusion along said tube, an integral hinge formed at a juncture between said base and said generating means for pivoting of said generating means between a first position and a second position about an axis substantially parallel to the longitudinal axis of said tube; and resisting means biased to yieldably urge said generating means toward said first position and against said base for operative engagement of said generating means with said tube.
a base for supporting said tube in a substantially linear orientation;
peristaltic means for generating a moving zone of occlusion along said tube, an integral hinge formed at a juncture between said base and said generating means for pivoting of said generating means between a first position and a second position about an axis substantially parallel to the longitudinal axis of said tube; and resisting means biased to yieldably urge said generating means toward said first position and against said base for operative engagement of said generating means with said tube.
14. An apparatus as recited in claim 13 wherein said peristaltic means comprises:
a cam shaft having a plurality of cams spaced in a helical relationship therealong; and a plurality of fingers operatively connected with said cams.
a cam shaft having a plurality of cams spaced in a helical relationship therealong; and a plurality of fingers operatively connected with said cams.
15. An apparatus as recited in claim 14 further com-prising a casing for operatively mounting said cam shaft thereon.
16. An apparatus as recited in claim 3 further comprising a housing fixedly associated with said base, said housing having a plurality of grooves for receiving said fingers therein to constrain said fingers for linear reciprocal movement
17. An apparatus as recited in claim 16 wherein said resisting means is a spring connected between said casing and said housing.
18. An apparatus as recited in claim 17 wherein said integral hinge is positioned with its transverse axis substantially parallel to the longitudinal axis of said cam shaft.
19. An apparatus as recited in claim 18 wherein said case comprises a platen.
20. A linear peristaltic pump for pumping fluids through an IV tube having a cam action compensator which comprises:
a platen mounted on said pump;
a housing fixedly attached to said pump to receive said tube between said housing and said platen.
a plurality of fingers slidably mounted on said housing to squeeze said tube between said fingers and said platen to create a moving zone of occlusion along said tube;
a cam shaft operatively coupled to said fingers;
a casing having said cam shaft rotatably mounted thereon;
an integral hinge connecting said casing to said housing, said hinge establishing an axis of rotation for said casing substantially parallel to the longitudinal axis of said cam shaft for movement of said casing between a first position and a second position; and resisting means biased to yieldably urge said casing toward said first position and onto said housing to compensate for the action between said fingers and said platen.
a platen mounted on said pump;
a housing fixedly attached to said pump to receive said tube between said housing and said platen.
a plurality of fingers slidably mounted on said housing to squeeze said tube between said fingers and said platen to create a moving zone of occlusion along said tube;
a cam shaft operatively coupled to said fingers;
a casing having said cam shaft rotatably mounted thereon;
an integral hinge connecting said casing to said housing, said hinge establishing an axis of rotation for said casing substantially parallel to the longitudinal axis of said cam shaft for movement of said casing between a first position and a second position; and resisting means biased to yieldably urge said casing toward said first position and onto said housing to compensate for the action between said fingers and said platen.
21. A peristaltic pump as recited in claim 20 wherein said cam shaft has a plurality of cams mounted in a helical relationship therealong.
22. A peristaltic pump as recited in claim 21 wherein said resisting means is a spring.
23. A peristaltic pump as recited in claim 22 wherein said fingers are formed with resilient arms to compensate for rotational motion of said fingers within said housing.
24. A peristaltic pump as recited in claim 23 further comprising a motor operatively connected with said cam shaft.
25. A linear peristaltic cam action compensator which comprises:
a casing;
a rotatable cam shaft operatively mounted on said casing, a plurality of fingers coupled to said cam shaft;
a housing for establishing linear reciprocal movement of said fingers in response to the rotation of said cam shaft, an integral hinge pivotally connecting said casing to said housing, said hinge establishing an axis of rotation for said casing substantially parallel to the longitudinal axis of said cam shaft for movement of said casing between a first position and a second position; and resisting means yieldably connecting said housing to said casing to bias said casing toward said first position and resist movement of said casing about the hinge axis.
a casing;
a rotatable cam shaft operatively mounted on said casing, a plurality of fingers coupled to said cam shaft;
a housing for establishing linear reciprocal movement of said fingers in response to the rotation of said cam shaft, an integral hinge pivotally connecting said casing to said housing, said hinge establishing an axis of rotation for said casing substantially parallel to the longitudinal axis of said cam shaft for movement of said casing between a first position and a second position; and resisting means yieldably connecting said housing to said casing to bias said casing toward said first position and resist movement of said casing about the hinge axis.
26. A compensator as recited in claim 25 wherein said cam shaft further comprises cams operatively connected with said fingers for peristaltic movement of said fingers.
27. A compensator as recited in claim 10 further com-prising a resilient tube; and a platen operatively associated with said housing to hold said tube therebetween.
28. A compensator as recited in claim 27 wherein said fingers are formed with resilient arms to ensure linear movement of said fingers relative to said housing.
29. A compensator as recited in claim 28 wherein said hinged connection is oriented with its transverse axis substantially parallel to the longitudinal axis of said cam shaft.
30. A compensator as recited in claim 29 wherein said resisting means is a spring.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US17,846 | 1987-02-24 | ||
| US07/017,846 US4728265A (en) | 1987-01-30 | 1987-02-24 | Peristaltic pump with cam action compensator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1300977C true CA1300977C (en) | 1992-05-19 |
Family
ID=21784865
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000536615A Expired - Lifetime CA1300977C (en) | 1987-02-24 | 1987-05-07 | Cam action compensator |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US4728265A (en) |
| EP (1) | EP0283614B1 (en) |
| JP (1) | JPS63209662A (en) |
| AT (1) | ATE66621T1 (en) |
| AU (1) | AU590179B2 (en) |
| CA (1) | CA1300977C (en) |
| DE (1) | DE3772556D1 (en) |
Families Citing this family (88)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4755109A (en) * | 1987-04-03 | 1988-07-05 | Fisher Scientific Company Inc. | Snap-together peristaltic mechanism |
| IT1223121B (en) * | 1987-11-13 | 1990-09-12 | Bellco Spa | PULSATILE PUMP FOR EXTRA BODY CIRCULAR |
| US4950245A (en) * | 1988-07-08 | 1990-08-21 | I-Flow Corporation | Multiple fluid cartridge and pump |
| US5131816A (en) * | 1988-07-08 | 1992-07-21 | I-Flow Corporation | Cartridge fed programmable ambulatory infusion pumps powered by DC electric motors |
| EP0399118A1 (en) * | 1989-05-23 | 1990-11-28 | Imed Corporation | Pumping mechanism |
| JP2859306B2 (en) * | 1989-07-24 | 1999-02-17 | テルモ株式会社 | Infusion pump |
| DE69033292T2 (en) * | 1989-07-31 | 2000-01-05 | Terumo Corp | Peristaltic pump |
| US5211548A (en) * | 1989-07-31 | 1993-05-18 | Terumo Kabushiki Kaisha | Peristaltic pump having a motor overload protector |
| GB8923130D0 (en) * | 1989-10-13 | 1989-11-29 | Cook Edward J | Pump |
| US4909710A (en) * | 1989-10-23 | 1990-03-20 | Fisher Scientific Company | Linear peristaltic pump |
| US5103211A (en) * | 1989-11-02 | 1992-04-07 | Ivac Corporation | Apparatus for detecting fluid line occlusion |
| EP0429866B1 (en) * | 1989-11-02 | 1994-05-25 | Ivac Corporation | Apparatus and method for measuring pressure in a fluid line for detecting an occlusion in said fluid line |
| US4988069A (en) * | 1989-11-27 | 1991-01-29 | Baxter International Inc. | Stepping motor mounting |
| US5037274A (en) * | 1989-12-05 | 1991-08-06 | Infometrix, Incorporated | Peristaltic apparatus and method for pumping and/or metering fluids |
| US4954046A (en) * | 1989-12-08 | 1990-09-04 | Imed Corporation | Peristaltic pump with mechanism for maintaining linear flow |
| DE4006763A1 (en) * | 1990-03-03 | 1991-09-05 | Braun Melsungen Ag | LINEAR TUBE PUMP |
| US5158437A (en) * | 1990-03-15 | 1992-10-27 | Abbott Laboratories | Volumetric pump with spring-biased cracking valves |
| US5055001A (en) * | 1990-03-15 | 1991-10-08 | Abbott Laboratories | Volumetric pump with spring-biased cracking valves |
| US5180287A (en) * | 1990-03-15 | 1993-01-19 | Abbott Laboratories | Method for monitoring fluid flow from a volumetric pump |
| US5357827A (en) * | 1990-03-15 | 1994-10-25 | Abbott Laboratories | Torque compensated cam assembly and method |
| US5116203A (en) * | 1990-03-15 | 1992-05-26 | Abbott Laboratories | Detecting occlusion of proximal or distal lines of an IV pump |
| US5039279A (en) * | 1990-03-15 | 1991-08-13 | Abbott Laboratories | Sensor for detecting fluid flow from a positive displacement pump |
| US5078362A (en) * | 1990-03-15 | 1992-01-07 | Abbott Laboratories | Spring-biased valve for use in a positive displacement volumetic pump |
| IL98786A0 (en) * | 1991-07-11 | 1992-07-15 | Yeda Res & Dev | Peristaltic pump |
| US5217355A (en) * | 1991-08-05 | 1993-06-08 | Imed Corporation | Two-cycle peristaltic pump with occlusion detector |
| US5221268A (en) * | 1991-12-06 | 1993-06-22 | Block Medical, Inc. | Multiple dose control apparatus |
| US5263831A (en) * | 1992-02-19 | 1993-11-23 | Cobe Laboratories, Inc. | Peristaltic pump |
| DE4214068A1 (en) * | 1992-04-29 | 1993-11-04 | Pfeiffer Ulrich | DEVICE FOR DETERMINING THE VOLUME AND / OR THE THROUGHPUT OF A PATIENT'S CIRCUIT SECTION |
| EP0655107B1 (en) * | 1992-06-09 | 2002-10-16 | Baxter International Inc. | Programmable infusion pump with interchangeable tubing |
| JPH06102151A (en) * | 1992-09-18 | 1994-04-15 | Mitsubishi Yuka B C L:Kk | Dispensing device |
| US5453246A (en) * | 1992-09-18 | 1995-09-26 | Mitsubishi Yuka Bio-Clinical Laboratories, Inc. | Dispensing apparatus |
| US5447417A (en) * | 1993-08-31 | 1995-09-05 | Valleylab Inc. | Self-adjusting pump head and safety manifold cartridge for a peristaltic pump |
| US5609575A (en) * | 1994-04-11 | 1997-03-11 | Graseby Medical Limited | Infusion pump and method with dose-rate calculation |
| US5542826A (en) * | 1994-09-12 | 1996-08-06 | Ivac Corporation | Fluid delivery system with mounting linkage |
| US6234773B1 (en) | 1994-12-06 | 2001-05-22 | B-Braun Medical, Inc. | Linear peristaltic pump with reshaping fingers interdigitated with pumping elements |
| US5660529A (en) * | 1994-12-06 | 1997-08-26 | Mcgaw, Inc. | Linear peristaltic pump with reshaping fingers interdigitated with pumping elements |
| EP0797741B1 (en) * | 1994-12-22 | 2003-03-19 | Oseney Limited | An end mounting for a ram housing |
| US5904668A (en) * | 1995-03-06 | 1999-05-18 | Sabratek Corporation | Cassette for an infusion pump |
| US5628619A (en) * | 1995-03-06 | 1997-05-13 | Sabratek Corporation | Infusion pump having power-saving modes |
| US5637093A (en) * | 1995-03-06 | 1997-06-10 | Sabratek Corporation | Infusion pump with selective backlight |
| US5620312A (en) * | 1995-03-06 | 1997-04-15 | Sabratek Corporation | Infusion pump with dual-latching mechanism |
| US5795327A (en) * | 1995-03-06 | 1998-08-18 | Sabratek Corporation | Infusion pump with historical data recording |
| AU750280B2 (en) * | 1996-04-10 | 2002-07-11 | Baxter International Inc. | Method of placing sensors in contact with a tube |
| WO1999011309A1 (en) * | 1997-08-29 | 1999-03-11 | Seiko Epson Corporation | Transfusion device and liquid supply tube |
| US6532835B1 (en) | 1997-12-12 | 2003-03-18 | Research International, Inc. | High efficiency wetted surface cyclonic air sampler |
| US6468242B1 (en) | 1998-03-06 | 2002-10-22 | Baxter International Inc. | Medical apparatus with patient data recording |
| US6699529B2 (en) * | 2002-05-20 | 2004-03-02 | Engelhard Corporation | Method for coating vehicular radiators with ozone depleting slurry catalyst |
| US7329545B2 (en) * | 2002-09-24 | 2008-02-12 | Duke University | Methods for sampling a liquid flow |
| US8308457B2 (en) | 2004-11-24 | 2012-11-13 | Q-Core Medical Ltd. | Peristaltic infusion pump with locking mechanism |
| IL165365A0 (en) * | 2004-11-24 | 2006-01-15 | Q Core Ltd | Finger-type peristaltic pump |
| US7556481B2 (en) * | 2005-08-26 | 2009-07-07 | Baxter International Inc. | Rotary axial peristaltic pumps and related methods |
| IL179234A0 (en) * | 2006-11-13 | 2007-03-08 | Q Core Ltd | An anti-free flow mechanism |
| IL179231A0 (en) * | 2006-11-13 | 2007-03-08 | Q Core Ltd | A finger-type peristaltic pump comprising a ribbed anvil |
| US8535025B2 (en) | 2006-11-13 | 2013-09-17 | Q-Core Medical Ltd. | Magnetically balanced finger-type peristaltic pump |
| IL179229A0 (en) * | 2006-11-13 | 2007-03-08 | Q Core Ltd | Magnetically balanced finger-type peristaltic pump |
| US8449500B2 (en) * | 2007-11-16 | 2013-05-28 | Baxter International Inc. | Flow pulsatility dampening devices for closed-loop controlled infusion systems |
| US10265454B2 (en) * | 2008-07-25 | 2019-04-23 | Baxter International Inc. | Dialysis system with flow regulation device |
| US8371832B2 (en) * | 2009-12-22 | 2013-02-12 | Q-Core Medical Ltd. | Peristaltic pump with linear flow control |
| US8142400B2 (en) * | 2009-12-22 | 2012-03-27 | Q-Core Medical Ltd. | Peristaltic pump with bi-directional pressure sensor |
| US9677555B2 (en) | 2011-12-21 | 2017-06-13 | Deka Products Limited Partnership | System, method, and apparatus for infusing fluid |
| US8366667B2 (en) | 2010-02-11 | 2013-02-05 | Baxter International Inc. | Flow pulsatility dampening devices |
| WO2011128850A2 (en) | 2010-04-12 | 2011-10-20 | Q Core Medical Ltd | Air trap for intravenous pump |
| EP2663359B1 (en) | 2011-01-16 | 2017-11-01 | Q-Core Medical Ltd. | Methods, apparatus and systems for medical device communication, control and localization |
| US20120257986A1 (en) | 2011-04-11 | 2012-10-11 | Ahmad Momeni | Rotary cam actuated linear peristaltic pump |
| WO2013001425A2 (en) | 2011-06-27 | 2013-01-03 | Q-Core Medical Ltd. | Methods, circuits, devices, apparatuses, encasements and systems for identifying if a medical infusion system is decalibrated |
| US9163623B2 (en) * | 2011-12-08 | 2015-10-20 | Carefusion 303, Inc. | System and method for improved flow uniformity in a peristaltic pump mechanism |
| US9675756B2 (en) | 2011-12-21 | 2017-06-13 | Deka Products Limited Partnership | Apparatus for infusing fluid |
| US11295846B2 (en) | 2011-12-21 | 2022-04-05 | Deka Products Limited Partnership | System, method, and apparatus for infusing fluid |
| WO2013142552A1 (en) | 2012-03-21 | 2013-09-26 | Bayer Materialscience Ag | Roll-to-roll manufacturing processes for producing self-healing electroactive polymer devices |
| TW201403899A (en) | 2012-04-12 | 2014-01-16 | Bayer Materialscience Ag | EAP transducers with improved performance |
| JP6019718B2 (en) * | 2012-05-02 | 2016-11-02 | セイコーエプソン株式会社 | Liquid transport apparatus and liquid transport method |
| WO2013192143A1 (en) | 2012-06-18 | 2013-12-27 | Bayer Intellectual Property Gmbh | Stretch frame for stretching process |
| EP2885868A4 (en) | 2012-08-16 | 2016-04-13 | Bayer Ip Gmbh | Rolled and compliant dielectric elastomer actuators |
| US9855110B2 (en) | 2013-02-05 | 2018-01-02 | Q-Core Medical Ltd. | Methods, apparatus and systems for operating a medical device including an accelerometer |
| KR101504012B1 (en) * | 2013-06-27 | 2015-03-18 | 장관순 | Intravenous delivery device |
| US20150133861A1 (en) | 2013-11-11 | 2015-05-14 | Kevin P. McLennan | Thermal management system and method for medical devices |
| US10143795B2 (en) | 2014-08-18 | 2018-12-04 | Icu Medical, Inc. | Intravenous pole integrated power, control, and communication system and method for an infusion pump |
| WO2016033016A1 (en) * | 2014-08-27 | 2016-03-03 | Vidacare LLC | Pumping apparatuses and methods for fluid infusion |
| WO2016044146A2 (en) | 2014-09-18 | 2016-03-24 | Deka Products Limited Partnership | Apparatus and method for infusing fluid through a tube by appropriately heating the tube |
| CA2987011A1 (en) | 2015-05-26 | 2016-12-01 | Icu Medical, Inc. | Disposable infusion fluid delivery device for programmable large volume drug delivery |
| USD914196S1 (en) * | 2018-08-16 | 2021-03-23 | Deka Products Limited Partnership | Peristaltic pump |
| USD918396S1 (en) | 2018-08-16 | 2021-05-04 | Deka Products Limited Partnership | Central controller |
| USD914197S1 (en) | 2018-08-16 | 2021-03-23 | Deka Products Limited Partnership | Syringe pump |
| US11707615B2 (en) | 2018-08-16 | 2023-07-25 | Deka Products Limited Partnership | Medical pump |
| USD914195S1 (en) | 2018-08-16 | 2021-03-23 | Deka Products Limited Partnership | Syringe pump |
| US20220305197A1 (en) * | 2019-04-23 | 2022-09-29 | Carefusion 303, Inc. | Silent pumping mechanism for infusion pump |
| USD939079S1 (en) | 2019-08-22 | 2021-12-21 | Icu Medical, Inc. | Infusion pump |
| US11679189B2 (en) | 2019-11-18 | 2023-06-20 | Eitan Medical Ltd. | Fast test for medical pump |
Family Cites Families (25)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1055516A (en) * | 1910-10-26 | 1913-03-11 | American Lithographic Co | Hinge. |
| US2483304A (en) * | 1945-12-11 | 1949-09-27 | Vogel Rudolf | Container |
| US3137242A (en) * | 1962-01-22 | 1964-06-16 | Hahn George William | Infusion pump |
| US3140666A (en) * | 1962-06-11 | 1964-07-14 | American Instr Co Inc | Peristaltic pump |
| GB1287951A (en) * | 1969-06-12 | 1972-09-06 | ||
| US3582234A (en) * | 1969-07-14 | 1971-06-01 | Technicon Corp | Method and apparatus for the calibration of tubing to provide for a desired flow rate therethrough |
| US3737251A (en) * | 1971-02-08 | 1973-06-05 | Alphamedics Mfg Cop | Peristaltic pump |
| CA1036420A (en) * | 1975-09-25 | 1978-08-15 | Baxter Travenol Laboratories | Peristaltic pump with forgiving rollers |
| US4155362A (en) * | 1976-01-26 | 1979-05-22 | Baxter Travenol Laboratories, Inc. | Method and apparatus for metered infusion of fluids |
| CH633352A5 (en) * | 1978-11-29 | 1982-11-30 | Doltron Ag | Hose pump. |
| US4233001A (en) * | 1979-02-28 | 1980-11-11 | Peerless Electronics Research Corporation | Peristaltic pump |
| US4278085A (en) * | 1979-12-13 | 1981-07-14 | Baxter Travenol Laboratories, Inc. | Method and apparatus for metered infusion of fluids |
| JPS56113083A (en) * | 1980-02-12 | 1981-09-05 | Terumo Corp | Choke detection method and device for peristaltic liquid pump |
| FR2492902A1 (en) * | 1980-10-27 | 1982-04-30 | Secan | Finger-operated peristaltic perfusion pump - has drive camshaft to deform flexible pipe over greater length in first half turn |
| CH653639A5 (en) * | 1981-01-21 | 1986-01-15 | Zeller Plastik Koehn Graebner | ONE-PIECE HINGE PLASTIC. |
| JPS587253A (en) * | 1981-07-04 | 1983-01-17 | テルモ株式会社 | Drug liquid pouring apparatus |
| US4414705A (en) * | 1981-07-17 | 1983-11-15 | Ethyl Products Company | Overcenter hinge |
| DE3202251A1 (en) * | 1982-01-25 | 1983-08-11 | MGVG Medizinische Geräte Vertriebs-Gesellschaft mbH, 8000 München | Hose pump |
| US4482347A (en) * | 1982-08-12 | 1984-11-13 | American Hospital Supply Corporation | Peristaltic fluid-pumping apparatus |
| JPS60230582A (en) * | 1984-04-27 | 1985-11-16 | Hitachi Ltd | Roller type squeeze pump |
| US4653987A (en) * | 1984-07-06 | 1987-03-31 | Tsuyoshi Tsuji | Finger peristaltic infusion pump |
| US4561830A (en) * | 1984-10-01 | 1985-12-31 | Ivac Corporation | Linear peristaltic pump |
| US4559038A (en) * | 1984-10-19 | 1985-12-17 | Deltec Systems, Inc. | Drug delivery system |
| US4617014A (en) * | 1985-11-26 | 1986-10-14 | Warner-Lambert Company | Dual mode I. V. infusion device |
| US4671792A (en) * | 1986-02-18 | 1987-06-09 | American Hospital Supply Corporation | Pressure-regulating peristaltic pump |
-
1987
- 1987-02-24 US US07/017,846 patent/US4728265A/en not_active Expired - Lifetime
- 1987-05-06 AT AT87304047T patent/ATE66621T1/en active
- 1987-05-06 DE DE8787304047T patent/DE3772556D1/en not_active Expired - Lifetime
- 1987-05-06 EP EP87304047A patent/EP0283614B1/en not_active Expired - Lifetime
- 1987-05-07 CA CA000536615A patent/CA1300977C/en not_active Expired - Lifetime
- 1987-05-18 JP JP62121003A patent/JPS63209662A/en active Granted
- 1987-08-05 AU AU76578/87A patent/AU590179B2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| ATE66621T1 (en) | 1991-09-15 |
| DE3772556D1 (en) | 1991-10-02 |
| EP0283614A1 (en) | 1988-09-28 |
| US4728265A (en) | 1988-03-01 |
| AU590179B2 (en) | 1989-10-26 |
| JPS63209662A (en) | 1988-08-31 |
| AU7657887A (en) | 1988-08-25 |
| EP0283614B1 (en) | 1991-08-28 |
| JPH0412144B2 (en) | 1992-03-03 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1300977C (en) | Cam action compensator | |
| US4725205A (en) | Peristaltic pump with cam action compensator | |
| EP0282324B1 (en) | Improved pump pressure sensor | |
| AU622088B2 (en) | Peristaltic pump with mechanism for maintaining linear flow | |
| CA1127491A (en) | Medical infusion system | |
| EP0781378B1 (en) | Fluid delivery system with mounting linkage | |
| US5056992A (en) | IV pump and disposable flow chamber with flow control | |
| AU2001238698B2 (en) | Force sensor assembly for an infusion pump | |
| CA1259871A (en) | Fluid infusion pump driver | |
| US5447417A (en) | Self-adjusting pump head and safety manifold cartridge for a peristaltic pump | |
| US5326236A (en) | Compliant rotor for an improved cartridge for drug infusion pump | |
| US5092749A (en) | Fluid pump drive mechanism | |
| AU2001238698A1 (en) | Force sensor assembly for an infusion pump | |
| JPS59501395A (en) | Medical infusion pump device and disposable cassette | |
| EP0291158A1 (en) | Peristaltic pumping device and method of assembling the same | |
| EP0527868A1 (en) | Disposable infusion apparatus with peristaltic pump | |
| US20100063448A1 (en) | Pump assembly comprising actuator system | |
| JPH0599154A (en) | Spring energizing valve for positive displacement type pump device | |
| EP0293241B1 (en) | Intravenous pump with disposable chamber | |
| JPH0531176A (en) | Medical liquid pump | |
| KR0117201Y1 (en) | Portable automatic injector | |
| CN117915968A (en) | Infusion device with fluid line fixation |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |