US20070144753A1 - Transducerized rotary tool - Google Patents
Transducerized rotary tool Download PDFInfo
- Publication number
- US20070144753A1 US20070144753A1 US11/708,826 US70882607A US2007144753A1 US 20070144753 A1 US20070144753 A1 US 20070144753A1 US 70882607 A US70882607 A US 70882607A US 2007144753 A1 US2007144753 A1 US 2007144753A1
- Authority
- US
- United States
- Prior art keywords
- rotary tool
- tool
- motor
- torque
- chuck assembly
- 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.)
- Abandoned
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
- B25B21/00—Portable power-driven screw or nut setting or loosening tools; Attachments for drilling apparatus serving the same purpose
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
- B25B23/00—Details of, or accessories for, spanners, wrenches, screwdrivers
- B25B23/14—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers
- B25B23/147—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers specially adapted for electrically operated wrenches or screwdrivers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25F—COMBINATION OR MULTI-PURPOSE TOOLS NOT OTHERWISE PROVIDED FOR; DETAILS OR COMPONENTS OF PORTABLE POWER-DRIVEN TOOLS NOT PARTICULARLY RELATED TO THE OPERATIONS PERFORMED AND NOT OTHERWISE PROVIDED FOR
- B25F5/00—Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for
- B25F5/02—Construction of casings, bodies or handles
- B25F5/025—Construction of casings, bodies or handles with torque reaction bars for rotary tools
- B25F5/026—Construction of casings, bodies or handles with torque reaction bars for rotary tools in the form of an auxiliary handle
Abstract
Disclosed herein is a variable speed tool useful for use with securing or removing industrial fasteners. The tool also includes a means to torque the fastener to a certain precise torque. The tool can be used with an associated controller that provides control commands to the tool.
Description
- This application claims priority from co-pending U.S. application having Ser. No. 11/315,952 filed Dec. 22, 2005, the full disclosure of which is hereby incorporated by reference herein.
- 1. Field of the Invention
- The invention relates generally to the field of automatic drivers for fasteners. More specifically, the present invention relates to an apparatus for driving fasteners that is automatic and controllable. Yet more specifically, the present invention relates to a device for driving fasteners, where the apparatus delivers a specified torque.
- 2. Description of Related Art
- Many prior art devices exist that are capable of driving fasteners apertures, such as threaded bolt holes and the like. These tools typically require the user to activate a switch or a trigger to activate the device. Further, some prior art devices rely on power sources such as compressed air to drive the associated motor, which can limit the applicability of a device since producing compressed air requires space for a compressor and is generally impractical. Other devices that employ electrical motors produce an output whose speed and torque can vary and is not precisely controllable or not controllable at all. However many instances where it is required to employ a rotary tool, the ability to control the speed and torque is important. Some fasteners require that they be installed to a specified torque, and it is important that how much the fastener has been torqued be easily verified by the operator of the device.
- Some of these devices include means to measure the rotational force, or torque, exerted by the particular device. These means range from monitoring the current consumed by the device, pressure sensors applied to working parts of the device, and included various sensors within the device. Examples of prior art devices useful for driving fasteners can be found in U.S. Pat. No. 4,487,270, U.S. Pat. No. 4,887,499, U.S. Pat. No. 6,424,799, U.S. Pat. No. 4,571,696, and U.S. Pat. No. 4,502,549.
- Therefore, there exists a need for an apparatus and a method for securing fasteners that is reliable, accurate, and can precisely torque a fastener to a specified torque. An additional need exists for a tool to be durable, hand held, and provide an indication the preciseness of the directly torqued value.
- Disclosed herein is a rotary tool comprising a motor connected to a chuck assembly. Included with the tool is a variable voltage device responsive to a magnetic field. The motor may be selectively controlled by operation of the variable voltage device—where the control includes on off switching as well as motor speed control. The tool includes a push to start function; that is by urging the tool against the object being rotated the tool's rotational force and velocity is based on the urging force. Optionally, the variable voltage device can be a Hall effect sensor, either linear or digital. Also included is a gearbox connectively disposed between the motor and the chuck assembly. Lubrication comprising two parts gear oil and one part motor grease is disposed within the gearbox.
- A field device is included on the chuck assembly that is capable of emitting a magnetic field. Positioning the field device by selective movement of the chuck assembly controllably drives the motor. This is done since positioning the field device manipulates the magnitude of the magnetic field provided to the variable voltage device from the field device. The magnitude of the magnetic field proportionally relates to the proximity of the variable voltage device in relation to the field device.
- The rotary tool can further include a lever assembly having a field device formed thereon. The field device within the lever is also capable of emitting a magnetic field. Positioning the field device within the lever by selective movement of the lever assembly can controllably drive the motor. Positioning the field device manipulates the magnitude of the magnetic field applied to the variable voltage device from the field device within the lever. The magnitude of the magnetic field within the lever field device proportionally relates to how close the variable voltage device is in relation to the field device. Optionally, a handheld pistol grip assembly can be employed in lieu of the lever assembly.
- A torque transducer may be included capable of measuring the value of the torque generated by the chuck assembly. Optionally included with the transducer is at least one strain gauge in cooperative engagement with the torque transducer. The at least one strain gauge transmits data representing the torque generated by the chuck assembly. This data monitored by the strain gage is usable to terminate operation of the driver when the torque generated by the chuck assembly reaches a predetermined amount.
- Also optionally included with the rotary tool is at least one selector switch programmably capable of selectively reversing the polarity of the electrical power supplied to the driver. Additional selector switches can be included that are also programmable. The additional selector switches can be capable of selectively operating the driver in a different control mode.
- Optionally, a system may be included to drive fasteners comprising a rotary tool combinable with a controller assembly. Here the rotary tool includes a motor capable of providing a rotational force, a chuck assembly operatively connectable to the motor, and a variable voltage device responsive to a magnetic field. The motor is in operative communication with the variable voltage device. The controller assembly should be capable of providing control instructions to the rotary tool where the control instructions comprise maximum torque magnitude, speed, among other operational variables.
-
FIG. 1A depicts one embodiment of the present invention. -
FIG. 1B illustrates an exploded view of one embodiment of the present invention. -
FIGS. 2A-2E provide a partial cut-away version of embodiments of the present invention. -
FIG. 2F provides a cutaway view of an embodiment of the present invention. -
FIG. 2G illustrates a frontal view of an embodiment of the present invention. -
FIG. 2H illustrates a side view of a tranducerized element. -
FIGS. 3A and 3B depict a cutaway view of an embodiment of the present invention. -
FIGS. 4A and 4B depict a cutaway view of an embodiment of the present invention. -
FIG. 5 presents an embodiment of the present invention combined with a controller. -
FIG. 6 provides an exploded view of a gear box in combination with a motor. -
FIGS. 7A and 7B provide side and perspective views of embodiments of a tool grip. - Disclosed herein is a rotary tool system comprising a rotary tool combined with a controller system. With reference to the drawings herein, one embodiment of the
rotary tool 10 is shown in perspective view inFIG. 1A and an exploded view inFIG. 1B . Therotary tool 10 is useful for driving fasteners, such as bolts, nuts, screws, self-threading screws, etc. Further, therotary tool 10 is capable of repeatably applying fasteners to a precise specifiable torque. In the embodiment shown inFIG. 1B , amotor 36 is included capable of initiating a force used to torque the fasteners. - In the embodiment of
FIGS. 1A and 1B agear box 38 is shown disposed adjacent themotor 36 is operative connected to themotor 36. Thegear box 38 contains a series ofgears 39 configured into a gear train or system in mechanical cooperation with themotor 36. Thegears 39 are arranged to receive the output rotational force delivered by themotor 36 and convert that force into a specified torque at theoutput shaft 40 connected to thegear box 38. In one embodiment the gear train is comprised of at least two gear stages, where each stage converts the rotational torque and speed produced by themotor 36. Thegear box 38 increases the torque delivered by themotor 36 with a corresponding decrease in the rotational speed of themotor 36. The range of torque output at thegear box 38 ranges from about 1 in-lb to about 50 in-lb. - To maximize torque/velocity conversion while minimizing space, the gear system may be a planetary gear system comprising sun and planet gears.
FIG. 6 provides an embodiment of amotor 36 combined with agear box 38, where thegear box 38 is shown in an exploded view. As shown, the firststage sun gear 86 is attached to themotor 36 and engages a series of threeplanetary gears 88. Theplanetary gears 88 are all attached to aplanet carrier 91, from which extends asecond sun gear 93 into a secondplanetary gear stage 95. The output shaft of the second gear stage is theoutput shaft 40. Sealing thegearbox 38 eliminates gear maintenance and protects the gears from foreign matter such as dirt. The lubricant used in the gearbox may be two parts gear oil with one part of motor grease. This combination of oil and grease provide an exceptional high-pressure lubricity, and low viscosity in order to minimize the amount of lubricant used, which in turn reduces viscous shear.Needle rollers 89 can be included between the annulus between the inner diameter of each planet gear (of each stage) and the outer diameter of thespindle 93 it rides on. The use ofneedle rollers 89 in this location of thegearbox 38 significantly reduces friction and wear. Theneedle rollers 89 also hold lubrication very well. The quantity ofneedle rollers 89 for use with each gear depends on the size of the individual gear and the gear box, it is believed that determining this quantity is within the scope of those skilled in the art. - To minimize contact between gear stages an
axle bearing 90 is disposed into a conical cavity between the planets on the centerline of each planet carrier (91 and 97). When the mating sun gear (86 and 93) from the previous stage (or the motor 36) is inserted between the planet gears (88 and 94), its face comes to rest against theaxle bearing 90. The axle bearing may be comprised of a hardened metal ball. Examples of metals include stainless steel and chrome steel, however this ball could be made from any number of hardenable materials. This configuration produces very little friction since theaxle bearing 90 and the sun gears (86 and 93) are in tangential contact. When these two stages are rotating with respect to each other, the material surface velocities at the point of contact are low, which minimizes moment arm. - In order to adequately handle axial and radial loads on the
output shaft 40 of thegearbox 38 as well as limit axial and radial play, a combination of two bearings is used. The bearing on the outboard most end of the gearbox is a conventional radial bearing. This bearing is meant to carry any side loads placed on theoutput shaft 40 as well as a small amount of axial load. The inboard bearing is an angular contact bearing. This bearings primary function is to carry the axial loads, which are transmitted down the output shaft as well as a small amount of radial load. The load coupling of these two bearings is accomplished by a small spacer of a precisely held thickness, which is sandwiched between the inner races of both bearings. These bearings, in combination, produce a very free spinning, durable and accurate mechanism. - Enhanced performance and efficiency has been realized by some of the design improvements to the
gear box 38, for example, thesplined output shaft 40 was strengthened to carry more torsional load. The gearbox output shaft retainer ring (not shown) was improved to carry more axial load without breaking free. Heat treatment, such as by nitriding, was added to surfaces on the planet carriers that come into contact with rotating planet gears. High-carbon steel alloy axles were included with the planet carriers to improve fatigue properties also the thickness of rear gearbox end cap was adjusted to minimize axial gear clearances. - Table 1 provides a summary of sample configurations of gear systems providing varying output torque, included with the table are the corresponding speed and ratios of the possible stages in the particular gear system.
TABLE 1 1st stage 2nd stage 3rd stage combined Torque Speed ratio ratio ratio ratio 10 in/lb 1800 4.285:1 4.285:1 none 18.36:1 20 in/lb 1100 6.75:1 4.285:1 none 28.92:1 35 in/lb 800 6.75:1 6.75:1 none 45.56:1 50 in/lb 500 4.285:1 4.285:1 4.285:1 78.68:1 - Optionally the
rotary tool 10 can be tranducerized to provide a real-time monitoring of the magnitude of the torque exerted onto a fastener by therotary tool 10. Preferably the torque monitoring system include aflexure 25 secured to thegear box 38 on the end of thegear box 38 opposite to where it is connected to themotor 36. At least onestrain gauge 85 can be included within theflexure 25 that senses the torque supplied by themotor 36 and transmits that sensed torque information to thetool controller 80. Preferably fourstrain gages 85 are included with theflexure 25. Theflexure 25 is connected on its other end to thenose cap 26. As can be seen inFIG. 1 , thenose cap 26 includesslots 27 on its outer surface that mate withtabs 17 formed on the front end of thebody 12 of therotary tool 10. As themotor 36 supplies torque to the fastener, themotor 36 in turn transmits an identical torque value tonose cap 26. Since the themotor 36 is mounted to theflexure 25, theflexure 25 experiences the torque supplied by themotor 36. Thus by positioning astrain gage 85 on theflexure 25, the torque output of themotor 36 can be measured by thestrain gage 85. As the tool communicates with atool controller 80, the torque output of thestrain gage 85 connects to thetool controller 80 as well. When the output torque of themotor 36 reaches a pre-selected torque, thetool controller 80 is programmable to immediately deactivate power to therotary tool 10, thus ensuring that the fastener being secured by therotary tool 10 is not over tightened. - The
strain gage 85 may be calibrated as an assembly using what is known as a “dead weight” calibrator. Weights, which are certified and traceable to NIHST, are used to generate a static moment by placing them on an arm at a specific distance. The calibration does not occur until the at least onestrain gage 85 is combined within therotary tool 10. This is done in order to take into account frictional losses in the tool. Preferably, the at least onestrain gage 85 can be a standard encapsulated strain gage that is modulus compensated for use on aluminum flexures. The signal produced by the detection of strain in the at least onestrain gage 85 is carried to thecontroller 80 analog via theflex circuit 33 and thetool cable 82. Theflex circuit 33 attaches directly to the flex circuit therefore eliminating wiring in therotary tool 10. When fourstrain gages 85 are used they may be attached to each other in a wheatstone bridge configuration and optionally using fine polyester varnished wire. As shown, the four dualelement strain gages 85 are located 90° from each other on theflexure 36. Fourstrain gages 85 can minimize bending cross talk and improve accuracy. - A
chuck assembly 28 is provided with the embodiment ofFIGS. 1A and 1B and is connectable to theoutput shaft 40, preferably through corresponding spline grooves formed on the outer surface of theshaft 40 and an aperture (not shown) formed axially within theshaft 29 of thechuck assembly 28. As will be explained in further detail below, the length of the aperture should be long enough to allow theshaft 29 to slide back and forth along a portion of the length of theoutput shaft 40. Asocket 31 is provided on one end of thechuck assembly 28, thesocket 31 shown is suitable for receiving a fitting (not shown) specifically sized to fit the particular fastener being driven by therotary tool 10. Further, asleeve 33 is provided that when tugged axially retracts a retaining ball within thesocket 31 thereby enabling adding or removing the particular fitting for use with therotary tool 10. Also disposed on thechuck assembly 28 is acollar 35 slidable along theshaft 29. Thecollar 35 includesthreads 32 on the outer surface adjacent thenut 30 formed to fit threads (not shown) in thenose cap 26. Aring magnet 34 is disposed on the end of theshaft 29 opposite thesocket 31. A snap ring (not shown) is included on theshaft 29 that retains thecollar 35 on the shaft between thesleeve 33 and the snap ring. Thus while thecollar 35 remains on theshaft 29, it must be free to slide along theshaft 29 between thesleeve 33 and the snap ring. Accordingly when thechuck assembly 28 is screwed to thenose cap 26, theshaft 29 can be slideably disposed in and out of the collar 35 a certain distance while still being retained within thechuck assembly 28. - The rotary tool is useful not only for driving and securing fasteners, but can also be useful as a drill motor, a sander, a buffer, a saw, and any other application where a driving force is used. Moreover, the novel application of the push to start feature disclosed herein is applicable with all functions for which the present device can be used.
- Referring now to
FIGS. 3 and 4 , other electrical circuitry that can be included with the present invention include variable voltage devices (VVD) such as a Hall effect sensor. As is well known, the output voltage of the VVD depends on the magnetic flux density applied to the VVD. Thus, subjecting the VVD to a magnetic field can increase the output voltage of a VVD. Likewise, removing the magnetic field can eliminate the VVD output voltage. Accordingly a switching mechanism can be produced by combining a field device that produces a magnetic field, such as a magnet, with a VVD. A simple application of this phenomenon involves creating a voltage source by positioning a magnet (either permanent or electro) close to a Hall effect sensor. One example of a field device is a permanent magnet, and one example of a VVD is a Hall effect sensor. - In
FIGS. 3A and 3B one example of such a switching device can be seen. As can be seen fromFIG. 3A , thechuck assembly VVD 73 is disposed on theflexure 25. As previously pointed out, theshaft 29 is slideable within thecollar 35 and is thus axially moveable with respect to the rest of therotary tool 10. Absent a force urging theshaft 29 inward toward therotary tool 10, it is pushed outward by aspring 42 and is in its extended position as seen inFIG. 3A . When theshaft 29 is in the extended position, the magnetic field emitted by thefield device 34 has little or no effect on thechuck assembly VVD 73 and thechuck assembly VVD 73 will emit no voltage. In contrast, when theshaft 29 is pushed inward into a retracted position, thefield device 34 should be sufficiently proximate to thechuck assembly VVD 73 that it will emit voltage. It is preferred that when theshaft 29 is fully retracted that the interaction between thefield device 34 and thechuck assembly VVD 73 be such that thechuck assembly VVD 73 emit its maximum voltage. The voltage emitted from thechuck assembly VVD 73 should be used to drive themotor 36. Therefore, themotor 36 can be activated or deactivated by retracting and extending theshaft 29. It should also be pointed out that like all VVDS thechuck assembly VVD 73 will begin to emit a higher voltage in response to an increase in the strength of the magnetic field applied to it by thefield device 34. Thus the closer thefield device 34 is to thechuck assembly VVD 73, the more voltage thechuck assembly VVD 73 will emit, and in turn the faster themotor 36 will operate. Accordingly, one of the many advantages of the present invention is the ability to initiate operation of themotor 36 by slowly retracting theshaft 29, and to operate themotor 36 at variable speeds depending on how far inward theshaft 29 is retracted. - Alternatively, the
motor 36 can be variably driven by manipulation of thelever 20. Referring now toFIGS. 4A and 4B , an alternative embodiment is disclosed. Here alever field device 76, such as a permanent magnet, is disposed within the body of thelever 20. Thelever 20 is hingedly attached to therotary tool 10 on one of its ends viapins 54 inserted into ports of theend cap 18. A correspondinglever VVD 78 is preferably positioned within agroove 47 formed on the outer surface of awiring shell 46. Similar to thechuck assembly 28, aspring 21 is included to urge the free end of thelever 20 outward away from the body of therotary tool 10. Urging thelever 21 toward the body of therotary tool 10, thelever field device 76 should begin to approach the proximity of thelever VVD 78. Also similar to the operation of thechuck assembly VVD 73, thelever VVD 78 will begin to emit voltage to themotor 36 as thelever field device 76 approaches it. Thus themotor 36 can be manipulated by depressing thelever 21 in much the same manner as it is manipulated by retracting theshaft 29. - Optionally, the
lever 21 can be replaced by apistol grip assembly 61, where thepistol grip assembly 61 comprises ahandle 65, abase 69, andtrigger 72. Thehandle 65 provides a grip for the users hand. Thebase 69 is secured to thehandle 65 and securable to thebody 12 of therotary tool 10. Thetrigger 72 can be hingedly attached to thebase 69 and include atrigger field device 74 disposed thereon such that when thetrigger 72 is depressed thetrigger field device 74 is moved towards thebody 12. Thepistol grip assembly 61 should be secured to thebody 12 such that thetrigger field device 74 will be proximate to thelever VVD 78 when thetrigger 72 is depressed. Thus therotary tool 10 can be actuated by depressing thetrigger 72. - Two or more selector buttons (14 and 16) can optionally be provided to enhance the flexibility of the
rotary tool 10 functions. Each selector button (14 and 16) can contain a field device, such as a permanent magnet within. When assembled, the selector buttons (14 and 16) should be aligned with selector button VVDS (70 and 71) disposed within thegroove 47.Springs 15 should be included with each selector button (14 and 16) to urge the buttons outward from thebody 12 of therotary tool 10 absent a force pushing the buttons inward. By programming the associatedcontroller 80, actuation of the selector buttons (14 and 16) inward can vary the function of therotary tool 10. For example, thecontroller 80 can be programmed such that inwardly pressing thefirst selector button 14 will toggle the polarity of the voltage delivered to themotor 36 thereby reversing the rotational direction of thechuck assembly 28. Additional options include the requirement that the buttons (14 and 16) be depressed twice, similar to the operation of a mouse of a personal computer, before the requested function occur. The selector buttons (14 and 16) can be programmed to initiate or control any number of external devices or process either directly or indirectly related to the operation of the tool. More commonly the selector buttons (14 and 16) can be used to control the direction of rotation of the tool as well as changing preprogrammed tool set points or parameter sets. It is believed that the programming of the associatedcontroller 80 can be accomplished by those skilled in the art without undue experimentation. - While standard wiring or circuit boards could be used, it is preferred that the circuitry of the rotary tool be included on a
flex circuit 33. Theflex circuit 33 can provide a way to conduct power to drive themotor 36 and provide wiring to conduct control commands as well. As is well known, theflex circuit 33 can be comprised of a flexible resin like material, as such theflex circuit 33 can be tailored to fit within the present invention while consuming a minimum amount of space within therotary tool 10. Further, theillumination LEDS 58, theindication LEDS 62, and lever and selector button VVDS (70, 71, and 78) can be situated directly on theflex circuit 33. Design of anappropriate flex circuit 33 for use with the present invention is well within the capabilities of those skilled in the art. - A digitally programmable device, such as a memory chip, may be included with the
rotary tool 10. During final assembly and calibration of the tool, the programmable device may be programmed at least with identification, calibration, and operating conditions desired by therotary tool 10. The information can include the model number of thespecific rotary tool 10, serial number, date of manufacture, date of calibration, maximum speed and maximum torque that therotary tool 10 can attain, the calibration value, the motor angle counter per tool output revolution (this describes the gear ratio), and other useful operating parameters. Operation of the system requires constant real-time communication with atool controller 80. Programmed within thetool controller 80 are the operating parameters for thespecific rotary tool 10 being used. During use thetool controller 80 interrogates the memory chip within thespecific rotary tool 10 to ensure that the specific tool is capable of performing the intended task. If the tool is capable of performing the task at hand, the controller will allow thespecific rotary tool 10 to be operated; otherwise thecontroller 80 will not activate the tool. This interrogation happens upon power up or when thespecific rotary tool 10 is first connected to thecontroller 80. The controller can be programmed with a lap top computer using a graphic user interface under the Windows operating system. - Activation by the push to start mode includes the step of first inserting the fastener where it is to be fastened. For example, if the fastener is a threaded screw, in the push to start mode the screw will be inserted into the hole (threaded or unthreaded) where it is to be secured. Then a force can be applied by the operator to the rear end of the
rotary tool 10 that in turn pinches the screw between the fitting and the hole. As long as this force applied by the operator exceeds the spring constant of thespring 42, theshaft 29 will be retracted within thecollar 35. As previously noted when the shaft is retracted within thecollar 36, thefield device 34 is located proximate to thechuck assembly VVD 73—as is illustrated inFIG. 3B . As previously noted, when thefield device 34 approaches thechuck assembly VVD 73, voltage is emitted from thechuck assembly VVD 73 that in turn begins to drive themotor 36. Driving themotor 36 produces rotation of thechuck assembly 28 via thegear box 38 andoutput shaft 42. Rotation of thechuck assembly 28 can be used to drive the fastener into securing engagement with the associated hole by the transfer of rotational force from thechuck assembly 28 to the fastener. - Alternatively, the
rotary tool 10 can be operated by depressing thelever 20 up against thebody 12 of therotary tool 10. In the embodiment of the invention inFIGS. 4A and 4B alever field device 76 is shown disposed within thelever 20. As thelever 20 is depressed towards the body, thelever field device 76 approaches thelever VVD 78. In the same manner as the push to start mode, thelever VVD 78 begins to emit a voltage whose magnitude is in relation to the strength of the magnetic field applied to it by thelever field device 76. The voltage emitted by thelever VVD 78 can then be applied to driver themotor 36 where the magnitude of the voltage emitted by thelever VVD 78 directly corresponds to the rotational speed of themotor 36. - The push to start and throttle lever can either be used individually or in combination with each other. There are however instances where they are useful in combination. One can be used as an interlock for the other. It can be configured so that the throttle lever has to be fully depressed before the push to start can be activated. This configuration prevents operation of the tool before the operator has a good grip on it. Conversely it can be configured so that the push to start has to be fully depressed before the throttle can be activated. This configuration prevents the rotation of the tool before sufficient axial load is applied to the fastener as in the case of a self tapping screw. In the case of automated operation in a fixture, the push to start can be used as a form of presence detection.
- During the time the
rotary tool 10 is driving the fastener (either by the push to start mode or by depressing the lever 20), the magnitude of the torque delivered to the fastener by therotary tool 10 is measured by the at least onestrain gage 85 disposed within theflexure 25. The strain gage bridge produces an analog output that is continuously monitored during tool operation. The strain gages should be arranged in such a fashion as to be only sensitive to torsion along the axis of theflexure 25. Eachstrain gage 85 has two elements that are oriented 90 degrees to each other and 45 degrees to the axis of theflexure 25. There are four gages arrayed around the circumference of the flexure in 90° intervals. Under torsion the strain gages 85 will unbalance the Wheatstone bridge therefore producing an output. Under bending, compression, or tension the loads will cancel therefore maintaining a balanced bridge and producing little or no output. The torque value measured by the at least onestrain gage 85 is uploaded to thecontroller 80 as thecontroller 80 interrogates data from therotary tool 10. Thus, a real time measurement of the torque applied to the fastener can be obtained by thecontroller 80 through its constant monitoring of the at least onestrain gage 85. Further, thecontroller 80 can be programmed to instantaneously deactivate therotary tool 10 when the torque measured by the at least onestrain gage 85 matches the shut off torque stored in thecontroller 80. More specifically, when the torque as measured by thestrain gate 85controller 80 combination reaches the preselected torque, thecontroller 80 immediately and actively stops rotation of the tool, thus ensuring that the fastener being secured by the tool is not over tightened. The braking or stopping of the tool is accomplished through the use of plug reversing and dynamic braking. Plug reversing involves applying full reverse power to themotor 36 until thestrain gage 85 andcontroller 80 senses zero torque. Dynamic braking takes advantage of the fact that amotor 36 is also a generator. By shorting the power leads of themotor 36 to each other, the effect is to force themotor 36 to resist its own rotation in proportion to its rotational velocity. Therefore, one of the many advantages realized by the present invention is the ability to precisely tighten fasteners exactly to a desired torque without the danger of over or undertightening a fastener. This advantage is due in part to the real time monitoring of torque and the instantaneous response of thecontroller 80 actively deactivating therotary tool 10. - The controller can be programmed with a target torque and speed. Optionally the controller can be set to run the
rotary tool 10 at two different speeds. The first speed would be relatively high and would run until a selected torque, which is not the target torque, is reached. The second, or downshift speed, would run slower and then stop at the target torque. For example if the target torque is 20 in-lbs the controller may be set as follows: Initial speed of 1000 rpm until a down shift torque of 12 in-lbs is reached. Then a down shift speed of 250 rpm until the target torque is reached. Additionally, angle measurement and control can be implemented. Angle control can either be substituted for torque or used in combination with torque. An AND relationship can be established with torque and angle. By setting a torque target of 20 in-lbs and an angle target of 60°, both targets have to be met or exceeded in order to count as a successfully fastened joint. The angle count is started at a threshold torque of perhaps 10 to 20 percent of the target torque. In this case that would be 2 to 4 in-lbs. Other parameters can be set to form upper and lower torque and angle limits around the targets. For example with a 20 in-lb target the limits may include a torque low limit of 18 in-lbs and a high limit of 22 in-lbs with an angle low limit of 50° with an angle high limit of 70°. These limits are used to form a window around the target for the purposes of establishing the criteria for a properly torqued fastener. If the angle is to low before achieving the target torque then the fastener has likely cross threaded. If the angle is to high then the fastener has likely stripped, broken or was not present. - In one embodiment of the
motor 36 is coupled to agear box 38 comprised of two gear stages, where the two stages provide a conversion of speed to torque. In one example of operation the first stage has a speed to torque ratio of about 6.75:1 and the second stage has a speed to torque ratio of about 4.285:1. To maximize torque/velocity conversion while minimizing space, the preferred gear system is a planetary gear system. In this system the first stage sun gear is attached to the motor output shaft and engages a series of three planetary gears. The planetary gears are all attached to a planet carrier, from which extends a second sun gear into the next planetary gear stage. The output shaft of the second gear stage, which has a spline gear formed thereon, mates with the output drive. - In one embodiment the gearboxes are in a sealed oil gearbox. Sealing the gearbox eliminates gear maintenance, helps keep the gears clean, and protects the gears from foreign matter. The light oil in lieu of a more viscous lubricant, such as grease, greatly enhances the efficiency of torque transmission. One example of lubricating oil for use with the gears comprises a mix of two parts of synthetic gear oil with one part of motor assembly grease. The synthetic gear oil weight can range from 75W90 to 75W140 and weights in between. The motor assembly grease may comprise a calcium-based grease with an anti-wear rating. A lubricating oil formed with this composition provides a balance of good high-pressure lubricity, low viscosity as compared to conventional power tool greases, and enough tackiness to require only 1 milliliter of oil therefore greatly reducing viscous shear.
- With regard to the
field device 34 disposed on theshaft 29, in one embodiment thefield device 34 is a ring magnet that is plastic injection molded using permanent magnet particles (such as Neodymium Iron Boron) suspended in Nylon. This configuration provides relatively high field density combined with low cost. Further, the ring magnet should be radially magnetized, the outer diameter of the ring magnet is magnetized in a first polarity and the inner diameter is oppositely polarized. This is done so that the output of the Hall sensor within thechuck assembly VVD 73 stays consistent regardless of the rotational orientation of theshaft 29. It is preferred that the Hall output vary as a result of axial movement only. If the ring magnet were magnetized with alternating poles on the outside diameter, thechuck assembly 28 would stop rotating as the poles reversed. - The gears may be made from medium-carbon steel selected because of its hardness and heat-treating properties. Optionally, the gear material may comprise low-alloy steel optimized for nitriding. Medium-carbon steel or low-alloy steel optimized for nitriding may also be used in the planet carriers. In one embodiment, the gear axles are made from high-carbon steel that is a high strength gear material with excellent bending fatigue properties.
- Some of the advantages realized by the present invention include a high degree of reliability and durability. The operating limit of many fastening tools before failure is about 500,000 cycles, in fact tools that are capable of operating up to 1,000,000 cycles without failure are considered very durable. In contrast the present invention has been found to operate in excess of 5,000,000 cycles without failure, which greatly exceeds the durability expectations of such a tool. Further, the present invention is also capable of this high number of cycles when subjected to high duty cycle applications. That is when an operating process is being repeated very quickly with many cycles per hour. Additionally, the performance of a
gear box 38 produced in accordance with the specifications of this application is superior to many other gear boxes used for similar applications. For example, similar type gear boxes generally have a maximum operation rotational speed at up to 7000-8000 revolutions per minute (rpm), whereas thegear box 38 of the present invention is capable of rotational speeds up to 50,000 rpm. - The present invention described herein, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While a presently preferred embodiment of the invention has been given for purposes of disclosure, numerous changes exist in the details of procedures for accomplishing the desired results. For example, the push to start feature can be physically disabled. Also, all four torque capacities can optionally be available in fixture mount configurations. A different front end cap is supplied with the tool to allow for easier and more reliable mounting of the tool in fixtured applications. Instead of a tapered end cap with headlights, a threaded end cap with a shoulder is provided including two different styles of mounting flanges. The fixture mounted configuration allows for the minimization of center to center mounting distances. In effect the tools can be mounted on 1.125″ centers 1.125″ is the diameter of the tool. This is important when fasteners are located very close to each other. This is of primary concern in automated applications where there is no human interaction or when multiple tools are mounted in combination with each other in a hand operated power head. Further, the variable voltage device can be any device that responds to some external stimulus, such as voltage, current, pressure, or magnetic, or that switches at a threshold of stimulus. The variable voltage device can be selected from items such as a linear response device, or a digital response device.
- These and other similar modifications will readily suggest themselves to those skilled in the art, and are intended to be encompassed within the spirit of the present invention disclosed herein and the scope of the appended claims.
Claims (18)
1. A rotary tool comprising:
a motor;
a chuck assembly operatively connectable to said motor;
a gearbox operatively disposed between said chuck assembly and said motor; and
a lubricant in the gearbox comprising about two parts gear oil and about one part of motor grease.
2. The rotary tool of claim 1 , further comprising a variable voltage device responsive to a magnetic field, wherein said motor is in operative communication with said variable voltage device and wherein selectively moving the chuck assembly varies the magnitude of the magnetic field applied to the variable voltage device and proportionally varies the power supplied to said motor and thereby variably alters the corresponding rotational speed of the chuck assembly.
3. The rotary tool of claim 1 , wherein the gearbox comprises components formed by heat treatment.
4. The rotary tool of claim 3 , wherein the heat treatment comprises nitriding.
5. The rotary tool of claim 1 , wherein the gearbox comprises a first stage and a second stage.
6. The rotary tool of claim 5 , wherein the gear ratio of the first stage and the second stage is selected from the list consisting of 4.285:1, 6.75:1, and combinations thereof.
7. The rotary tool of claim 1 , wherein the gear oil comprises oil having a weight of from 75W90 to about 75W140.
8. The rotary tool of claim 1 , wherein the motor grease comprises a calcium-based grease with an anti-wear rating.
9. The rotary tool of claim 2 further comprising plastic injection molded permanent magnet particles for creating the magnetic field.
10. The rotary tool of claim 9 wherein the permanent magnet particles comprise neodymium iron boron.
11. The rotary tool of claim 1 further comprising a transducer having a strain gage.
12. The rotary tool of claim 11 further comprising a flexure combined with said strain gage.
13. The rotary tool of claim 1 , wherein said tool is hand held.
14. The rotary tool of claim 11 , wherein said transducer provides real time feed back information of the magnitude torque of the torque applied by the tool.
15. The rotary tool of claim 11 further comprising a controller that communicates with the rotary tool.
16. The rotary tool of claim 15 wherein said transducer provides said real time feed back information to the controller.
17. The rotary tool of claim 1 , wherein said tool is capable of accurately applying a magnitude of torque to a fastener that ranges from about 1 in-pounds to about 50 in-pounds.
18. The rotary tool of claim 1 , wherein said tool is capable of accurately applying a magnitude of torque to a fastener that ranges from about 1 in-pounds to about 20 in-pounds.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/708,826 US20070144753A1 (en) | 2005-12-22 | 2007-02-21 | Transducerized rotary tool |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/315,952 US7210541B2 (en) | 2002-09-03 | 2005-12-22 | Transducerized rotary tool |
US11/708,826 US20070144753A1 (en) | 2005-12-22 | 2007-02-21 | Transducerized rotary tool |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/315,952 Continuation US7210541B2 (en) | 2002-09-03 | 2005-12-22 | Transducerized rotary tool |
Publications (1)
Publication Number | Publication Date |
---|---|
US20070144753A1 true US20070144753A1 (en) | 2007-06-28 |
Family
ID=38192276
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/708,826 Abandoned US20070144753A1 (en) | 2005-12-22 | 2007-02-21 | Transducerized rotary tool |
Country Status (1)
Country | Link |
---|---|
US (1) | US20070144753A1 (en) |
Cited By (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20100331148A1 (en) * | 2009-06-24 | 2010-12-30 | Yihsuan Enterprise Co., Ltd. | Treadmill roller structure and treadmill |
EP2367658A1 (en) * | 2008-12-22 | 2011-09-28 | Atlas Copco Tools AB | Portable power wrench with a manually operated power control means |
US20110278035A1 (en) * | 2010-05-12 | 2011-11-17 | Bach Pangho Chen | Power control structure for electric power tools |
US20120085562A1 (en) * | 2009-06-11 | 2012-04-12 | Karl Johan Lars Elsmark | Portable power wrench with a gear casing and a parameter sensing device |
US20140011621A1 (en) * | 2011-03-31 | 2014-01-09 | Ingersoll-Rand Company | Ring gears configured to encase in-line torque transducers for power tools |
WO2014056905A1 (en) * | 2012-10-08 | 2014-04-17 | Robert Bosch Gmbh | Hand-held machine tool |
TWI458607B (en) * | 2010-04-21 | 2014-11-01 | X Pole Prec Tools Inc | Power tool power control structure |
US10357871B2 (en) | 2015-04-28 | 2019-07-23 | Milwaukee Electric Tool Corporation | Precision torque screwdriver |
TWI676348B (en) * | 2018-05-25 | 2019-11-01 | 車王電子股份有限公司 | electrical tools |
EP3663046A1 (en) * | 2018-12-07 | 2020-06-10 | SWEDEX GmbH Industrieprodukte | Screw driver assembly and method for operating same |
US11273543B2 (en) * | 2018-09-24 | 2022-03-15 | MollFAM S.r.l. | Installation tool for clamping rings |
US11400570B2 (en) | 2015-04-28 | 2022-08-02 | Milwaukee Electric Tool Corporation | Precision torque screwdriver |
US11413734B2 (en) * | 2018-10-17 | 2022-08-16 | Kyocera Senco Industrial Tools, Inc. | Working cylinder for power tool with piston lubricating system |
WO2022227633A1 (en) * | 2021-04-28 | 2022-11-03 | 歌尔股份有限公司 | Screw locking machine and screw feeding control method therefor |
US11534903B2 (en) * | 2017-08-28 | 2022-12-27 | Apex Brands, Inc. | Power tool two-stage trigger |
US11890741B2 (en) | 2019-05-13 | 2024-02-06 | Milwaukee Electric Tool Corporation | Contactless trigger with rotational magnetic sensor for a power tool |
Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4487270A (en) * | 1981-11-24 | 1984-12-11 | Black & Decker Inc. | Electric tool, particularly a handtool, with torque control |
US4502549A (en) * | 1982-03-25 | 1985-03-05 | Robert Bosch Gmbh | Spring-coupled power screwdriver |
US4518298A (en) * | 1982-03-25 | 1985-05-21 | Kabushiki Kaisha Sankyo Seiki Seisakusho | Head for industrial robot |
US4571696A (en) * | 1982-05-19 | 1986-02-18 | Robert Bosch Gmbh | Electronically controlled screwdriver with quality check indicator |
US4805404A (en) * | 1986-07-31 | 1989-02-21 | Societe D'exploitation F.F.D.M.-Pneumat | Portable pneumatic machine having embodied control electronics |
US5115701A (en) * | 1990-09-26 | 1992-05-26 | Gse, Inc. | Drive mechanism and strain gauge mounting for a nutrunner appliance |
US5898598A (en) * | 1996-10-25 | 1999-04-27 | Cooper Technologies Company | System and apparatus for a torque transducer with data processing capabilities |
US5898599A (en) * | 1993-10-01 | 1999-04-27 | Massachusetts Institute Of Technology | Force reflecting haptic interface |
US6424799B1 (en) * | 1993-07-06 | 2002-07-23 | Black & Decker Inc. | Electrical power tool having a motor control circuit for providing control over the torque output of the power tool |
US6523442B2 (en) * | 2000-12-07 | 2003-02-25 | Acradyne Inc. | Torque tool assembly |
US7090030B2 (en) * | 2002-09-03 | 2006-08-15 | Microtorq L.L.C. | Tranducerized torque wrench |
US7210541B2 (en) * | 2002-09-03 | 2007-05-01 | Microtorq Llc | Transducerized rotary tool |
-
2007
- 2007-02-21 US US11/708,826 patent/US20070144753A1/en not_active Abandoned
Patent Citations (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4487270A (en) * | 1981-11-24 | 1984-12-11 | Black & Decker Inc. | Electric tool, particularly a handtool, with torque control |
US4502549A (en) * | 1982-03-25 | 1985-03-05 | Robert Bosch Gmbh | Spring-coupled power screwdriver |
US4518298A (en) * | 1982-03-25 | 1985-05-21 | Kabushiki Kaisha Sankyo Seiki Seisakusho | Head for industrial robot |
US4571696A (en) * | 1982-05-19 | 1986-02-18 | Robert Bosch Gmbh | Electronically controlled screwdriver with quality check indicator |
US4805404A (en) * | 1986-07-31 | 1989-02-21 | Societe D'exploitation F.F.D.M.-Pneumat | Portable pneumatic machine having embodied control electronics |
US5115701A (en) * | 1990-09-26 | 1992-05-26 | Gse, Inc. | Drive mechanism and strain gauge mounting for a nutrunner appliance |
US6424799B1 (en) * | 1993-07-06 | 2002-07-23 | Black & Decker Inc. | Electrical power tool having a motor control circuit for providing control over the torque output of the power tool |
US5898599A (en) * | 1993-10-01 | 1999-04-27 | Massachusetts Institute Of Technology | Force reflecting haptic interface |
US6405158B1 (en) * | 1993-10-01 | 2002-06-11 | Massachusetts Institute Of Technology | Force reflecting haptic inteface |
US5898598A (en) * | 1996-10-25 | 1999-04-27 | Cooper Technologies Company | System and apparatus for a torque transducer with data processing capabilities |
US6523442B2 (en) * | 2000-12-07 | 2003-02-25 | Acradyne Inc. | Torque tool assembly |
US7090030B2 (en) * | 2002-09-03 | 2006-08-15 | Microtorq L.L.C. | Tranducerized torque wrench |
US7210541B2 (en) * | 2002-09-03 | 2007-05-01 | Microtorq Llc | Transducerized rotary tool |
Cited By (29)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8857533B2 (en) * | 2008-12-22 | 2014-10-14 | Atlas Copco Industrial Technique Aktiebolag | Portable power wrench with a manually operated power control means |
EP2367658A1 (en) * | 2008-12-22 | 2011-09-28 | Atlas Copco Tools AB | Portable power wrench with a manually operated power control means |
US20110259619A1 (en) * | 2008-12-22 | 2011-10-27 | Atlas Copco Tools Ab | Portable power wrench with a manually operated power control means |
CN102256748A (en) * | 2008-12-22 | 2011-11-23 | 阿特拉斯·科普柯工具公司 | Portable power wrench with a manually operated power control means |
EP2367658A4 (en) * | 2008-12-22 | 2012-05-16 | Atlas Copco Tools Ab | Portable power wrench with a manually operated power control means |
US8991518B2 (en) * | 2009-06-11 | 2015-03-31 | Atlas Copco Industrial Technique Aktiebolag | Portable power wrench with a gear casing and a parameter sensing device |
US20120085562A1 (en) * | 2009-06-11 | 2012-04-12 | Karl Johan Lars Elsmark | Portable power wrench with a gear casing and a parameter sensing device |
US20120100964A1 (en) * | 2009-06-24 | 2012-04-26 | Yihsuan Enterprise Co., Ltd. | Treadmill roller structure and treadmill |
US8282535B2 (en) * | 2009-06-24 | 2012-10-09 | Yihsuan Enterprise Co., Ltd. | Treadmill roller structure and treadmill |
US8348813B2 (en) * | 2009-06-24 | 2013-01-08 | Yihsuan Enterprise Co., Ltd. | Treadmill having roller structure |
US20100331148A1 (en) * | 2009-06-24 | 2010-12-30 | Yihsuan Enterprise Co., Ltd. | Treadmill roller structure and treadmill |
TWI458607B (en) * | 2010-04-21 | 2014-11-01 | X Pole Prec Tools Inc | Power tool power control structure |
US8689901B2 (en) * | 2010-05-12 | 2014-04-08 | X'pole Precision Tools Inc. | Electric power tool |
US20110278035A1 (en) * | 2010-05-12 | 2011-11-17 | Bach Pangho Chen | Power control structure for electric power tools |
US20140011621A1 (en) * | 2011-03-31 | 2014-01-09 | Ingersoll-Rand Company | Ring gears configured to encase in-line torque transducers for power tools |
US9212725B2 (en) * | 2011-03-31 | 2015-12-15 | Ingersoll-Rand Company | Ring gears configured to encase in-line torque transducers for power tools |
WO2014056905A1 (en) * | 2012-10-08 | 2014-04-17 | Robert Bosch Gmbh | Hand-held machine tool |
CN104684690A (en) * | 2012-10-08 | 2015-06-03 | 罗伯特·博世有限公司 | Hand-held machine tool |
US10029354B2 (en) | 2012-10-08 | 2018-07-24 | Robert Bosch Gmbh | Hend-held machine tool |
US11400570B2 (en) | 2015-04-28 | 2022-08-02 | Milwaukee Electric Tool Corporation | Precision torque screwdriver |
US10357871B2 (en) | 2015-04-28 | 2019-07-23 | Milwaukee Electric Tool Corporation | Precision torque screwdriver |
US11534903B2 (en) * | 2017-08-28 | 2022-12-27 | Apex Brands, Inc. | Power tool two-stage trigger |
TWI676348B (en) * | 2018-05-25 | 2019-11-01 | 車王電子股份有限公司 | electrical tools |
US20190363651A1 (en) * | 2018-05-25 | 2019-11-28 | Mobiletron Electronics Co., Ltd. | Power tool |
US11273543B2 (en) * | 2018-09-24 | 2022-03-15 | MollFAM S.r.l. | Installation tool for clamping rings |
US11413734B2 (en) * | 2018-10-17 | 2022-08-16 | Kyocera Senco Industrial Tools, Inc. | Working cylinder for power tool with piston lubricating system |
EP3663046A1 (en) * | 2018-12-07 | 2020-06-10 | SWEDEX GmbH Industrieprodukte | Screw driver assembly and method for operating same |
US11890741B2 (en) | 2019-05-13 | 2024-02-06 | Milwaukee Electric Tool Corporation | Contactless trigger with rotational magnetic sensor for a power tool |
WO2022227633A1 (en) * | 2021-04-28 | 2022-11-03 | 歌尔股份有限公司 | Screw locking machine and screw feeding control method therefor |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7210541B2 (en) | Transducerized rotary tool | |
US7090030B2 (en) | Tranducerized torque wrench | |
US20070144753A1 (en) | Transducerized rotary tool | |
US11400570B2 (en) | Precision torque screwdriver | |
US10357871B2 (en) | Precision torque screwdriver | |
US6523442B2 (en) | Torque tool assembly | |
JP4216724B2 (en) | Continuously variable transmission | |
US4822215A (en) | Thrust and torque sensitive drill | |
US6273221B1 (en) | Servo-motor brake | |
ATE304327T1 (en) | WRENCH WITH TORQUE INDICATOR | |
CA2648651A1 (en) | Screwdriving system with variably adjustable screwdriving spindles | |
US4850753A (en) | Positive feed device | |
CN108290301A (en) | Screwing device and method for being screwed into bolt in wall | |
JP2022537982A (en) | Power tools and torque-responsive gear units for power tools | |
US20090008115A1 (en) | Hand-held power tool with a slip clutch | |
TWM576947U (en) | Torque control apparatus of electric screwdriver | |
KR20190055291A (en) | Gear Box of Power Tool with Integral Type Collar | |
JP7383591B2 (en) | Electric screwdriver and electric screwdriver torque control device | |
US815066A (en) | Portable apparatus for transmitting motion to tools. | |
CN111283604A (en) | Torsion control device of electric screwdriver | |
CN207968190U (en) | A kind of novel servo electric cylinder | |
SU1726155A1 (en) | Turret head | |
KR20200001542U (en) | Torque adjusting assembly for electric screwdriver | |
JPS61501760A (en) | Ex-stress loading device for axially pre-stressed bearings | |
TH3543C3 (en) | Hong Mee Machine |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |