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Publication numberUS1157655 A
Publication typeGrant
Publication date19 Oct 1915
Filing date16 Apr 1913
Priority date16 Apr 1913
Publication numberUS 1157655 A, US 1157655A, US-A-1157655, US1157655 A, US1157655A
InventorsGeorge M Mayer, Frank T Fowler
Original AssigneeLife Saving Devices Company
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Resuscitating appliance.
US 1157655 A
Abstract  available in
Images(4)
Previous page
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Claims  available in
Description  (OCR text may contain errors)

Patented Oot. 19, 1915.

APPLICATION FILED APR.

G. M. MAYER & F. T. FOWLER.

REsusclTATlNG APPLIANCE G. lVl. IVIAYER & F. T. FOWLER.

RESUSCITATING APPLIANCE- APPLlcATloN FILED 111111.16. 1913.

Patented 06h19, 1915.

4 SHEETS-SHEE` 2 G. IVI. IVIAYER L F. T. FOWLER.

RESUSCITATING APPLIANCE.

APPucATmN FILED APR. 16. 1913.

Patented Oct. 19, 1915,

4 SHEETS-SHEET 3.

G. IVI. MAYER L F. T. FOWLER.

Rfsusclmms APPLIANCE. APPLICATION FILED APR. I6. I9I3. r IPaienued 0et.19, 1910.

4 SHEETS-SHEET 4.

57 @a Il 94 if il GEORGE MAYER AND FRANK T. FOWLER, OF CHICAGO, ILLINOIS, ASSIGNORS, BY DIRECT AND` MESNE ASSIGNMENTS, TO LIFE SAVING DEVICES COMPANY, A CORPO-` vein nation-or DELAWARE.

'i RESUSCITATING APPLIANCE.

ias-7,655.

Specification of Letters Patent.

patented oct. ia, rais.

Application filed April 16, 1913. Serial No. 761,587.

Be it known that We, GEORGE M. MAY-ER and FIL-mii T. FoWLnR, citizens of the United States, bothresiding at Chicago, in the county of Cook and State of llllinois, have invented certain new and useful Improvements in Resuscitating Appliances, of which the following is a specification.

\The present invention relates to a new and improved construction of mechanism or device for resuscitating people or animals by theintroduction of fiesh air, oxygen, or mixtures of these gases or other gases into the lungs of the patient, and the Withdrawal of the used gases from the lungs at regular intervals. v

Theinvention relates more particularly to that class of such mechanisms in which the flow of gases to and from the lungs is 'produced by some power or force other than the initial compression of the gases themselves. That is to sav, the invention relates particularly to that class of mechanism in which the operation of the device is brought about by some external agency,

` a n s .such as an operator or a specially driven motor..

lVhile the features of the present invention are applicable to use in mechanisms for resuscitating any species of lung-animal, still they are ofpeculiar applicability to the resuscitation of human beings, and therefore We shall describe the mechanism as applied particularly to this service. It will be understood. however', that in so doing, We in 'nowise limit ourselves to theuse of the ing abnormal pressures or vacuums within l the lungs. The mechanismor device for this purpose should Pbe so sensitive andvshculd be so associated with 'the other mechanisms that even in the hurry and confusion likely to' exist during the carrying on of the re- `suscitating operation, there will be no possibility of injuring the lungs of the patient. Utherwise permanentdamage or injury may result, such as would make it impossible to revive 'the patient under any circumstances. Forthis purpose, one yfeature of our invention contemplates the association or combination of suitably constructed safety devices with the pressure and suction mechanism, so as to limit the pressure at which the gas may be Kdelivered to the lungs and theo vacuum'under `Which it may be removed therefrom. The gas capacity of the lungs is largely dependent upon theage and size of the patient, and, of course, the volume of gas which will be drawn in and exhaled by ,the lungs at each breath is largely dependent upon the normal capacity of the lungs. lnasmuch as a mechanism which 1s' intended to induce artificial respiration should cause a lung movement as nearly normal as possible, itl follows that the volume of gases introduced into and Withdrawn from the lungs at each movement of the mechanism should correspond as nearly as possible to the nor-l mal capacity of the lungs. v

Therefore, another feature of our invention relates to the provision of devices or ar-4 rangements Wherebv the volume of gases which will be handled at each opeiation of the mechanism will correspond as nearly as possible to the natural volume. This feature contemplates the use of devices or arrangements whereby the capacity of the mechanism can be adjusted from time to time.

While it is a 'general proposition that an I excessive pressure or vacuum will not be created until an excessive amount of gas has been introduced into or withdrawn from the' lungs, still it is notv always possible to estimate accurately the exact capacity of the lungs, and, therefore, it might be found, even after the mechanism had been adjusted to give what was supposed to be the correct volume of gas movement. when the operation was commenced` that the lungs were of abnormal size. Therefore, ive have combined together the mechanisms for limiting the degrees of pressure or vacuum with the mechanisms for controlling the volume of gas, so that. taken together. they will constitute an efiicient and complete safeguard for the lungs.

Sometimes it is desired to reinforce the resuscitating action by the use of a certain percentage or proportion of oxygen in the l'iO gases. For example, in the case of asphyxiation, it might be desired to use a large percentage of oxygen, while in another case, ordinary air might be satisfactory.

Therefore, another feature of the invention relates to the provision of a valve mech.

anism or the like whereby the ratio or proportion between oxygen and air may be controlled' within wide limits, and whereby the proportion which will beintroduced at any instant can be estimated by examination of a scale or indicator.

Other objects and uses will appear from a detailed @description of the invention, which consists in the features of 'construction and combinations of parts hereinafter described and claimed.

In the drawings: Figure 1 shows a front elevation of the completed mechanism, with the pistons in lowered position; Fig. 2 shows a side elevation corresponding to that of Fig. 1; Fig. 3 is a section taken on line 3 3 of Fig. 1, looking in the direction of the arrows; Fig. .-1 is a section taken on line 1 -1 of Fig. 3, looking in; the direction of the arrows; Fig. 5 is a section taken on line 5 5 of Fig. 6-, looking in the direction of the arrows; Fig. 6 is an enlarged section taken on line 6 6 of Fig. 2, looking in the direction of the arrows; Fig. `7 isl an enlarged Section through the discharge checkvalve, and taken on line 7 7 of Fig. 6,

looking in the direction of the arrows; Fig.

S'is a cross section through a diaphragm valve, for limiting the amount of suction which may be created; Fig.` 9 is a cross section through a diaphragm Valve, for limiting the amount of pressure which may be created; Fig. 10 is a vvertical section through one of the cylinders ofthe mechanism, and shows vparticularly-the construction whereby the volume of gas handled at each operation of the .device-may be controlled; Fig. 11 is a detail section through Ithe gas mixing lvalve, and taken on line 11 11 of Fig. 6, looking in the direction of the arrows; Fig. 12 is a detail of the gas passages for the mixing valve, and is a section taken on line 12 12 -of Fig. 5, looking in the direction ofthe arrows; and Fig. 13' is' a detail section through the check-valve, through which the gas is delivered from the pressure. cylinder, and'is a sectiontaken on line 13 13 of Fig. 6, looking in the direction of the arrows.

lower end within a base' 18. The base is provided with a pair of side legs 19 and 20', which are spaced apart the proper distance to accommodate the foot of the operator, and are connected togetherby a base plate 21. i By means of this construction, a clear space is provided between the legs, so that thevoperator may place his foot on the base plate to steady the mechanism during its use. A number of rods or the like 22 are extended between the ears of the cap and the base, which rods serve to draw the base and cap securely against the ends of the cylinder tubes and hold the mechanism rigidly assembled. The cap and base serve the further functions of accurately spacing the cylinder tubes and of keeping them in perfect parallelism, so that a more accurate and smooth operation may be obtained.

Within the cylinders are mounted pistons 23 and 2l respectively, which pistons are preferably provided with upper and lower packing rings 25 and 26. Tubular piston rods 27 and 28 are connected to the pistons 23 and 2-1 respectively, said piston rods extending up through bearings 29 and 30 of the cap. These bearings are preferably lined by brass sleeves 31, so as to produce a bet\ ter wearing mechanism. An operating handle 32 is connected to the upper ends of the piston rods, by means of the pins 33,. and the upper ends of the piston rods are 4 closed by means of plugs 34.

With the mechanism as thus far described, the pistons can be forced up and down in unison by the raising and lowering of the handle 32, while the device as a whole is held rigidly in position by means of the foot plate 21. In the arrangement illustrated, each piston is of the so-called single acting type, that is, all of its work is performed on one stroke. lnasmuch as the up(A per portions of `the cylinders are closed, means'must be provided for permitting a free flow of air into and out from such portions of the cylinders. It is desired, however, to provide a construction whereby dust may be effectively excluded from the cylin- 'ders when the salne are not in operation.

In order to permit the air to flow into and out from the upper portions ofthe cylinders, we make use of hollow piston tubes. For this purpose, each of said tubes is provided with a perforation 35 in its lower portion, and a perforation 36 is provided in its upper portion. When the pistons stand in their lowermost positions, the upper perfo-rations stand vwithin their corresponding sleeves 31, thereby completelyT closing the upper portion of the cylinders. As soon as the upstroke commences, however, the perforations 36 move out from the sleeves 31, so that the air mayiow freely into and out 35 and 36 and `the hollow piston rods. It

will be understood, however, that the lower ends of the piston rods are completely closed, so that the spacesbeneath the pistons will properly perform their functions of compressing' andy rarifying the gases.

It was previously stated that in the construction illustrated, one of the cylinders performs the function of forcing thegas into the lungs, while the other withdraws the gas from the lungs. In practice, it is customary to secure a face mask or the like over the mouth and nose of the patient, and

the' present mechanism is provided with cate the proportions of the" mixture. prefer to mount the plug in vertical posiconnections fora tube 37, through which the fresh gases are forced to the face mask, and for a tube 38, through whichl the used gases are withdrawn from the face mask.' Between the connection 37 and the compression cylinder there is placed a valve 39, whose function it is to limit or control the pressure which may exist ini the delivery tube 37; and between the suction tube 38 and the suction cylinder there is provided a valve 40, whose function it is to limit the amount of, suction that may exist in the tube 38. Valves andpassages must be provided for properly directing the gases to and from the valves 39 and 40. I,

The compression cylinder is adapted to deliver either air. or oxygen or mixtures of the'same according to requirements, For this purpose, there is provided a mixing valve 41, which is mounted in an extension of the base and is provided with a plug 42 which can be turned into the desired position by a milled linger piece 43. A passage 44 has its inner end terminating at the plug,

and its outer end terminating in a' nipple 45,

to which may be connected a tuber46 leading from an oxygen generator. An air inlet opening' 47 communicates with the plug,

and a delivery passage 48 places the plug in lcommunication with the lower en d of the compression cylinder 15. As shown particularly in Fig; 12,-the plugis provided with a cut-away portion 49, so that com- Imunication maybe established between the passage 48 and the air inlet, or between the passage 48 and the oxygen passage,.orbe

tween the passage 48'and both the air inlet and oxygen passage simultaneously. When the latter condition exists, a mixture of air and oxygen will be handled by the compression cylinder. Manifestly, the proportion of air to oxygen will depend upon the exact position of the plug, and for the purpose of giving an indication as to what the proportion is at any instant,'we have provided a 'flange 50 on the plug, which flange has an indicating arrow or the like 51, which travels lover a scale 52 suitably formed or stamped on the base. This scale may be graduated in any suitable manner to indition, as illustrated, so that the scale may vlie on the upper surface of the base, where it can be easily read by the operator` as he manipulates the apparatus. t

A delivery passage 53 leads from the lower end of the compression cylinder to an up' standing tube 54, which in turn leads directly to the valve 39. In orderv tol direct the flow of gases through the compression cylinder, we have provided a suction valve 54a at the inner end of the inlet passage 48, and a discharge valve 55 at the outer end of the discharge passage These valves are preferably ball check-valves, although, of course, any desired construction may be used. In the particular arrangement illustrated, the

inlet valve has a' ball 56, seating in an enlargement at the end of the passage` 48 and held in place by means of a perforated nipple 57, which screws directly into the base .above the ball and has the notch 57a in its lower surface to provide communication bentween the passage 48 and the cylinder even inner end. This check-valve is similar inel00 construction to the valve 54a. The gases are discharged from lthe cylinder 16 down ,through the check-valve 61, which isiillustrated in detail in F ig. 7. It comprises a casing 62, having a U-shaped passage 63, one

-of the arms of which carries the check ball 64, and the other arm of which connects to the lower end of the cylinder. Theball may be held in place in any suitable manner as by means of a transversely extending wire 65. In order to provide as large a clear space as possible between the legs 19 and 20,

-the check valve 61 should seat close up against the leg 20. For this reason there is not sufficient clearance to allow said checkvalve to be rotated for-the purpose of screwing it into place. `We have, therefore, provided a\nipple 66 threaded on its interior to receive one arm of the valve 62, and thread ed on` its exterior to screw into the base of the machine.

The valves 39 and 40 are shown in detail i in section in Figs. 8 and 9. Said valves )are of diaphragm construction and are subjected to the influence of pressure and suc.- tion respectively, and may be `adjusted to limit the pressure of delivery of gas to the lungs and the'suction under which 'theI gas is removed. rlhe valve 39 has the diaphragm 67`dividing its interior into the spaces 68 and 69. ,The space 68 communicates with the atmosphere through the medium of a against a seat'73, when the diaphragm is forced back against the tension of a spring 7st, by reason of the existence of -an excessive pressure in the space 69. The outer end 0f said spring seats within a threaded plug 75, which can be adjusted back and forth in order to adjust the amount of compression in the spring for the purpose of regulating the mechanism. A cap 76 serves to protect the exposed end of the plug 75 and to give a finished appearance to the mechanism.

The valve l() is similar in construction to the valve 39, but, of course, the valve 40 is adapted to close under suction instead of under pressure. For this purpose the diaphragm is connected to a threaded pin 77,

upon which is threaded a plug 78 and con-1 tacting therewith is the compression spring 79. The inner end of this spring seatsdirectly against a bridge 80, so that theV diaphragm is normally thrown over into the position illustrated in Fig. 8. By adjusting the plug 7 8 back and forth on the pin, the

A amount of compression in the spring can be Ladjusted according to the suction at which it is desired that the valve shall close against the .seat 7 8a.

In the construction illustrated, we regulate or determine the volume of gas to be handled at each operation of the mechanism, by regulating or determining the stroke of the pistons. For this purpose, we have pro-- vided means for limiting said stroke and for adjusting its amount according to .requiremeuts. On the cap 17, there is mounted a disk 81 which is held in place and is free to rotate within an encircling ring 82. \This disk carries a casing 83 within lwhich works a finger piece 84:, best shown in Fig. 10, and whichis normally forced mward by means of a spring 85. The inner end of the finger piece carries a wedge block. 86 having its inner yface beveled upward, and the outer end l 'I of the finger piece carries. a knob or the like 87. Throughout the length of the piston rod 27, a number of notches 88 are provided,

whichl are of a size to accommodate the' block 86, but-are spaced at various positions of angularity around the piston rod. The piston rod is secured to the handle 32, so that it cannot ro-tate, and therefore each one of the notches 88 travels up and down in a vertical line. The sleeve 30 which s upports the upper end of the piston rod 27 is provided with notches 89 corresponding in number and angular position to the notches 88, and permitting the block 86 of the finger piece to rest or seat against the piston rod as the same travels up and down. By rotating the disk 81 into any given position, so as to allow the block 86 to extend through the corresponding notch 89, said block will stand in position to enter the corresponding notch 88 when the piston rod has traveled up the necessary distance, thus obstructing the piston rod in its travel and preventing a further upward movement. However, the piston rod will be free to move down again by reason of the beveled face on the end of the block 86.

inasmuch as the various notches 88 are at different positions of elevation on the piston rod, it follows that the length of stroke can be adjusted by throwing the finger piece into position to engage the desired notch.

Ve prefer to place markings ina conspicuous place, so that the exact position of the finger piece can be predetermined. For this purpose, we have placed said markings on the upper surface of the ring 82, as shown particularly in Fig. 3, and have placed an arrow 90 on the disk 81, which arrow will point to the corresponding markings. As a. simple means of division, we have illustrated the words Infants, 5 years,7 13 years, and Adults, inasmuch as these form convenient lines of division between the different pistcn strokes desired. Of`- course, any other suitable divisions might be used, and the divisions might be of greater or less number, as desired.

In order to facilitate .carrying the mechanism from `place to place, we have provided means for locking the cap to the handle 32, which means we have illustrated in Fig. 4. It comprises a piston plug 91 mountcling casing 95, so that, when it is desired to unlock the device, the piston plug can be pulled out by means of the finger piece to disengage the latter from the slot, and then the finger piece can be locked in such outer position by rotation. Y

In the construction illustrated, we have placed the diaphragm valves in vertical alinement and directly in front of the two cylinders. 'By so doing, the parts are brought within a. minimum space, so that the apparatus can be packed and handled most conveniently. Furthermore, by mounting the disk 81 on the cap 17, where it can be readily observed; and by placing the scale 52 on the upper face of the base, we have brought all of the indicating devices into positions where they can be most readily observed by the operator as he manipulates the mechanism. By providing a lock between the handle 32 and the cap 17, we have supplied a construction of mechanism llO which can be readily carried' about, and whereby any free movement of the pistons is obviated when the apparatus is not in use. v v

l/Vhile we have herein shown and described a mechanism by Imeans of which the volume of gas handledat each stroke can be controlled,aiid also a mechanism whereby excessive pressures and vacuums can beprevented, still there might arise occasions .when either one or both of these mechanisms might be dispensed with, as, for example, when the capacity of the lungs was definitely known, or when the operator might be willin to rely entirely upon the diaphragm valves for preventing the excessive pressures and vacuums. In other words, while there may be times when it is' desirable to use both of these mechanisms, still under some circumstances either one or the othei'inay be dispensed with.

`inasmuch as the rate of respiration of infants and children is different from that of adults, and in fact varies largely according to the age of the infant or child, it is desirable to have an indication as to the appro` priate number of strokes per minute for the particular patient yunder treatment. F or this purpose we take advantage of the pres` ence of the ring 82 on which the age markings are placed, and we place markings on j said ring adjacent to the age markings and corresponding to the number of strokes or respirations per minute which should be executed for the particular age in question. For example, adjacent to the word infants we .place the marking 50, which is approximately the number of respirations per .minute which should be executed when treating infants.

llt is sometimes unnecessary to actually withdraw `the gases from the lungs by a vacuum inasmuch as there are times when the natural contraction of the muscles and diaphragm of the patient will serve to expel the gas from the lungs, at least to some veX- tent, so that i t becomes only necessary to force the gas into the lungs in the first place.

Therefore, we have provided means whereby thesuction cylindercan be thrown out of commission leaving only .the compression cylinder ready to deliver the gas to the lungs, after which i-t will be forced out by the natural contraction above mentioned. In the particular arrangementillustrated this means'comprises a plug valve 96 placed at a convenient poirtbetiveen the face mask and the suction cylinder, and, as illustrated, preferably being mounted in the diaphragm valve 40. This plug has its side wall cut away in such a manner that when turned in one position the'suction diaphragm valve 40 and the suction tube 38 can be placed in communication with the atmosphere through the opening 97, while when the plug is turnedinto ansuch position asto place `the delivery passage 48 into communication with the air inlet opening 47 and the oxygen passage 44; `With the mixing valve plug turned into this position oxygen and air will be drawn into the compression cylinder on the upstroke of the piston thereof. However, means must be provided for preventing the` oxygen coming in from the tube 46 under a slight pressure from passing directly across to the air inlet opening 47, and thus escaping when the piston of the compression cylinder is on its down-stroke. For this purpose we have provided a ball check valve 98 which permits air to be drawn in from the air inlet, but prevents a back flow of oxygen from the oxygen generator..

1We do not limit ourselves to the construction shown and described in the specification, except as called for inthe claims, but we contemplate'within the scope, of our invention any equivalent mechanisms operat-l ing in substantially the saine way to-produce substantially the saine results.

le claim: 1. In a device of the class described the combination with an inspirating cylinder,

the cylindery under pressure, adjustable,

means for positively arresting the movement of 'thel piston inI one` direction for the purpose of adjusting'the volumeof gas to be delivered byl the pistond oneach stroke, a scale in conjunction with said adjustable means, markings onsaid scale indicating' ages of patients, and markings on 'said scale indicating appropriate frequencies of reciprocations corresponding to the several positions of the adjustable means.-

3. In a device of the class described the combination with an inspirating cylinder, of a reciprocating piston mounted therein and adapted to deliver said portions of gas therefrom under pressure, adjustable means for positively arresting the movements bf the piston to thereby-control volumes of gas vto be delivered from the cylinder, and means for indicating appropriate frequencies of reciprocation of the piston corresponding to the several adjustments of said means.

4. In a device'of the class described the combination with an inspirating cylinder, ofa reciprocating piston mounted therein and adapted to deliver portions of gas therefrom under pressure, a piston rod connected Ito said piston for the purpose of reciprocating the same, a plurality of stops located at different longitudinal positions of said rod, said stops being placed at different angular positions on the rod, and a rotary stop member adapted to be thrown into position to be engaged by a desired one `of the stops on said rod to thereby limit the reciprocation of the piston rod and piston accordingly.

5. In a device of the class described the combination,ivith an inspirating cylinder, of a reciprocating piston mounted therein fortlie purpose of delivering portions of gas from the cylinder under pressure, a piston rod connected to said piston for reciprocating the same, a plurality of stops located y at ditferent longitudinal positions on the rod corresponding to desired extents of piston reciprocation, said stops being placed at varying angular positions on the rod, a ro- `tary member mountedin position to be engaged by a desired one of said stops, to

thereby limit the reciprocations of the piston, and a scale in yconjunction With said Inember` for the purpose of indicating appropriate frequencies of reciprocation corresponding to the various positions of said member. A

6. In a. device of the class described the a.v reciprocating piston mounted therein for the purpose of delivering portions of gas therefrom under pressure, a piston rod connected to said piston, stops on said rod, a

movable member mounted in position to be 'engagedby a desired one of said stops to correspondingly. limit the stroke of the piston rod and piston, and a scale in conjunction With said member for the purpose of indicating appropriate frequencies of re-v ciprocation corresponding to the several p0- s'itions ofsaid rod. y

7. In a device of the class described the combination with an inspiratingpcylinder, of

. a reciprocating piston mounted therein for the purpose of delivering portions of gas therefrom'un'der pressure, a piston rod connected to said piston for the purpose of in conjunction With said member, indica' tions on said scale corresponding to various ages of patients and corresponding indications on the scale for designating appro priate frequencies of piston reciprocation corresponding to theV several positions of said member.

8. In a device of the class described the combination ivitli an inspirating cylinder, a reciprocating piston mounted therein and adapted to deliver portions of gas therefrom under pressure, a conduit for delivering the gas from the cylinder, and a limiting valve in said conduit for the purpose oflimiting the pressure at which gas may be delivered fi'oni said conduit to a patients lungs.

9. In a device of the class described the combination with an inspirating cylinder,

of a reciprocating piston mounted therein for the purpose of delivering portions of gas combination with an inspirating cylinder and an exhaust cylinder, of reciprocating pistons mounted in both of said cylinders, the piston in the inspirating cylinder being adapted to deliver portions of gas under pressure to the patients lungs, and the pisrton in the exhaust cylinder being adapted to Withdraw portions of gas from the patients lungs, a mouth piece, a conduit leading from the' inspirating cylinder to the mouth piece, a' conduit leading from the0 mouth piece to the exhaust cylinder, a limit valve in the rst mentioned conduit to limit the pressure at which gas may be delivered to the patients lungs, and a limit valve in the last mentioned conduit to limit the suction at which the gas may be withdrawn from the patients lungs.

GEORGE M. MAYER. FRANK T. FOWLER.

Witnesses:

THOMAS A. BANNING, Jr.,

CHARLES F. PEREE.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2427419 *30 Jun 194516 Sep 1947Mechanical Resuscitator IncResuscitating apparatus
US2428451 *17 Feb 19457 Oct 1947Emerson John HPressure resuscitator
US2617410 *6 Dec 194911 Nov 1952Mechanical Resuscitator CorpMechanical resuscitator
US3461866 *1 Feb 196619 Aug 1969Alan WestleyManually operated artificial respirator
US4071025 *19 Sep 197531 Jan 1978Ruth Lee HesseLung-venting apparatus
US4167184 *28 Dec 197711 Sep 1979Ruth Lea HesseLung-venting apparatus
US5345929 *11 Jun 199113 Sep 1994Jansson Lars ErikPumping device
US798024417 Jul 200719 Jul 2011Neoforce Group, Inc.Emergency pulmonary resuscitation device
WO2001083293A1 *27 Apr 20018 Nov 2001Philippe MichelAutomatic underwater breathing membrane with integrated manual recharge
Classifications
U.S. Classification128/205.18
Cooperative ClassificationA61M16/0072