JPS6171975A - Torque wrench structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved torque wrench that increases torque.

BACKGROUND OF THE INVENTION The art of torque wrenches and similar tools provided for applying a predetermined torsional force through threaded fasteners, etc. of various constructions and machines involves increasing torque to indicate force. Special grades of wrenches exist that apply torque to a particular machine fastener such that the parts of the machine adjacent to the fastener establish the reaction parts or structures necessary to generate the required twisting force. provided for. That is, the applied torsional force is generated between the fastener and an adjacent associated reactive structure, rather than between the fastener and a distant unrelated reactive structure.

The special grades of torque wrench described above are typically driveable between a case containing a suitable torque-increasing drive having torque input and output members or components, and a fastener associated with the torque output component. A workpiece or fastener engagement component, such as a drive socket for engagement, and a reaction member or component for drive engagement between the case of the wrench and the associated structure of the fastener are provided. Additionally, the torque applied with the wrench is typically measured by a force indicating device engaged between the reaction piece and the case of the wrench.

The most common prior art wrench of the particular class involved here is U.S. Pat.
This is a wrench disclosed in No. 3.686.

In the prior art wrench constructions described above, the reaction piece is annular with a central opening freely rotatably housing the output spindle of the wrench configured to be driveably coupled to the associated fastener by a drive socket or the like. It is a part. The reaction component includes a pair of locking pins that engage locking pin receiving sockets or openings in a machine or structure with which the fastener to be acted upon is associated, and a pair of opposing radially outwardly projecting lever arms. ing. The lever arm is
Extending freely between associated pairs of spaced stop posts formed in the case of the wrench. The lever arm is
A fluid-filled bellows is mounted and the stop post has an adjustable stop to engage the bellows so that relative rotation of the reaction piece and wrench case is controlled by the bellows. This will add force to the The bellows is coupled to a suitable hydraulic pressure gauge that indicates the force exerted thereon, the pressure gauge being calibrated to indicate the force exerted by the wrench structure on the fastener acted upon by the wrench structure.

Although the prior art wrenches described above have proven useful, their hydraulic force sensing indicators are not as accurate as most other types and grades of high quality torque indicating wrenches and tools. The hydraulic force sensing reader described above is fragile and can be damaged or otherwise adversely affected during normal use and handling of the wrench structure described above.

The general acceptance and use in the industry of the prior art wrench structures described above is due to the fact that other similar or similar wrench structures with other or different force display reading devices have not been developed or available in the prior art. believed and understood.

OBJECTS AND FEATURES OF THE INVENTION It is an object of the present invention to provide an improved torque wrench construction of the above-mentioned special grade that is more accurate, more durable and more reliable.

Other objects and features of the present invention eliminate the installation and use of highly inaccurate, fragile, and unreliable hydraulic force-sensing readers engaged between opposing force-transmitting parts of a wrench structure, and instead , force transmitting deflection beams in the force transmitting structure of the wrench and the deflections of these beams are accurately measured;
and an associated electrical device for converting the measured deflection of the beam into a force measurement that corresponds exactly to the force exerted on the fastener acted upon by the wrench structure. The present invention provides a torque wrench with improved performance.

Other objects and features of the present invention provide that the actuated fastener removably engages and stops an associated structure and has a pair of outer free ends that engage a reaction stop portion of the case of the wrench structure. a reaction member having opposing radially outwardly projecting flexure beams; a fastener on the flexure beam responsive to the flexure of the beam and acted upon by the wrench; It is an object of the present invention to provide an improved torque wrench of the above-described special grade having a force measurement display having a strain gauge coupled to an electrical circuit with a digital readout to accurately display the applied force.

Objects and features of the present invention include not only a deflection beam and a novel electrical device that measures the deflection of the beam to accurately indicate the force exerted by a wrench on an associated fastener, etc. an improved special grade as described above which clearly satisfies or exceeds all national organization and industry specifications for the same special grade wrench with respect to accuracy, dimensions, weight and all significant operational characteristics; An object of the present invention is to provide a torque wrench structure.

Finally, it is an object and feature of the present invention to provide a general wrench as described above which should be less expensive to manufacture, easier to repair and maintain, more economical and more accurate and reliable in operation than similar grade wrenches provided by the prior art. Our objective is to provide torque wrench structures of the highest grade and characteristics.

The above and other objects and features of the invention will become more apparent from the following description of one exemplary preferred form and application of the invention, with reference to the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, the wrench W of the present invention includes a case 0 made of a cast metal front and rear part, in which a suitable gear train is disposed and supported.

Referring to FIGS. 1 and 5, gear train T includes an elongated input shaft 10 having front and rear ends preferably supported by bearings within a case as shown. The shaft 10 is
An input worm gear 11 is formed or mounted between its ends. The front end of the shaft 10 is accessible at the front of the case O and has a polygonal socket opening 12 in which a hand crank 13 is removably engaged.

Worm gear 11 is between and driveably engaged with a pair of spaced driven gears 14 on elongated shaft 15 . Shaft 15 is spaced laterally outwardly from opposite sides of shaft 10 and lies on an axis perpendicular to shaft 10, with suitable bearings spaced longitudinally thereof, as shown clearly in FIG. The assembly is preferably bearing supported within and by the case.

The shaft 15 is formed with a driven worm gear 16 (between its bearing assemblies) or is drivably mounted. The worm gear 16 driveably engages opposite sides of a central elongate output gear 170 formed on or drivably attached to the central tubular output shaft 18 .

Output shafts 18 lie on axes perpendicular to shafts 15 and spaced apart between shafts 150, which axes are parallel to and spaced apart from input shaft 10.

The gear 17 has a pair of large bearing cones 19 on a tubular shaft 18.
Between the front and rear ends of the shaft 18! It's in the middle. The bearing cone 19 is supported within the case by means of suitable anti-friction bearings, as clearly shown in the drawings.

The shaft 18 freely accommodates an elongated central drive spindle 20 having front and rear ends accessible at the front and rear ends of the case 0 . The spindle 20 is connected to the shaft 18 by a suitable releasable and selectively reversible ratchet drive R.
is drivably coupled to the shaft 18 so that it is concentric with the shaft 18 and driven directly by the shaft 18 in a clockwise or counterclockwise direction as required or as the environment requires.

In practice, the front end of the spindle protrudes forward from the case O a sufficient distance to allow manual engagement, and the ratcheting device R is able to rotate the spindle by manual engagement with the front end portion of the spindle. A spindle-driven fastener is configured to be manually rotatable relative to the remainder of the wrench structure, for example, to advance the fastener to a finger-tight locking position prior to tightening the fastener.

It should be noted that the precise nature and construction of the ratchet device R may vary widely in practice without departing from the broader aspects and spirit of the invention.

Although, in accordance with the foregoing, it has been avoided to overburden this disclosure with a detailed description of the ratchet device R, further description of the device will be kept to a minimum.

The basic form of the ratchet device used here is shown in FIG. Releasing and reversing the ratchet device
This is done by means of an operating sleeve 21 which engages around the front end portion of the spindle and is accessible and manually engageable at the front of the case a.

The spindle 20 has a central polygonal through-opening 22, which allows a polygonal drive stem or shaft ( (not shown) may be removably engaged in and through the opening 22.

In the reduction for implementing the invention, the gear train T is 8 (1
It has a large ratio of 0:1 and therefore large torsional forces are applied by the spindle 20 to the workpiece during repeated rotations of the crank 13 with little force or resistance.

In fact, the details of the case and the construction of the gear train T shown in the figures and thus hitherto described may be varied widely without affecting the novelty of the invention or losing its novelty. Accordingly, the structures described thus far will be treated in a concise and general manner so as not to overburden this disclosure.

To further explain the invention, the wrench structure W of the invention includes a reaction piece P shown separately in FIGS. 6 and 4. Part P is shown integrated according to the invention in FIGS. 2, 7 and 8.

The part P comprises a flat annular disc-shaped body B having a front surface 30, a rear surface 31 and a central through opening 32.

The body B possesses and/or carries a pair of locking pins L that project rearwardly from the rear surface 31 in radially outwardly spaced relationship on either side of its central axis. Lock pin L
For example, the actuated fastener projects freely from the rear face of the body and the rear part of the case 0 to engage a locking pin receiving socket (not shown) provided in the associated structure.

That is, in a structure or machine having a fastener or other component to be tightened with the wrench of the present invention, the structure or machine is locked in a predetermined circumferential and radial spaced relationship from the axis of the fastener or component being acted upon. A pin receiving socket (or equivalent) is provided, and the locking pin L is removably engageable with the socket.

In addition to the above, the body B of the part P is formed or fixed with two diametrically opposed and radially outwardly projecting flexible beams. The flexure beam D is shown as an elongated, flat, par-shaped member or section having flat front 30' and rear 31' faces and flat, straight side edges 33.

The outer free end of the flexible beam D has a stop pin receiving opening 34, into which the stop pin S fixed to the case 0 and projecting rearwardly from the case O can be freely engaged. It is inserted.

In a preferred implementation of the invention, as shown, the rear side of the case 0 is formed with a cavity or recess 40 that opens to the rear so as to freely accommodate the reaction part P.

The cavity 40 is normally substantially covered by a cover plate 41, which is removably fixed to the rear part of the body with screws and serves to hold the part P in a suitable manner.

Moreover, as shown, the central body B of the part P has a rear surface 3
1 is located at the rear of the case a and the plate 41, and protrudes rearward through the center entrance part 42 of the cover plate 41 so that the lock pin L can be completely approached.

With the above structure, when the wrench W is used, the wrench W is positioned such that the lock pin L that engages the lock pin socket of the associated structure or machine is aligned with the fastener or component associated with the socket; It is clear that the reaction part P is fixed against rotation of the fastener relative to the associated machine or structure. Moreover, the stop pin S, which is mounted in the case and engages an opening 34 in the outer end of the deflecting beam D of the part P, resists rotation with respect to the part P and therefore with respect to the structure of the workpiece or the machine. Fix or stop case 0 against rotation.

Therefore, the reaction between the fastener and the wrench will cause a reaction component P to the structure or machine of the workpiece that the lock pin L engages.
given directly through.

A reactionary force directed at and through the reaction part P is directed through the deflection beam D of the part and is directed laterally between the stop pin S and the body B of the part P. Deflecting these beams is even more obvious.

In addition to the above, the reaction part P has a strain gauge G fixed to the deflection beam D between the stop pin S and the body B of the part P. The strain gauge G is in the nature of a variable resistor, the resistance of which increases when the strain gauge acts on it and/or when it is deformed in response to a deflection or bending of the beam to which it is fixed. ,Change.

Strain gauge q is coupled to an electrical circuit, which may be generally of the nature of a bridge circuit or may be defined as a bridge circuit, which circuit acts to compare the resistances of strain gauge G and generates a composite signal. Transferred to a display device E, the device engineer converts the composite signal to display the force on the workpiece experienced by beam D and strain gauge G, where the number is the force applied to the workpiece by the wrench.

In a preferred implementation of the invention, four strain gauges G are fixed, one on each side 33 of each deflecting beam D, as clearly shown in FIGS. 6, 4, and 8. provided. The strain gauges G are in laterally spaced relation to the central longitudinal axis of the associated beam D, and therefore, upon deflection of the beam D transversely to the radially extending longitudinal axis, One strain gauge of the beam is subjected to tensile forces and the other strain gauge is subjected to compressive forces. That is, whenever the wrench structure is used, all four strain gauges are active, two experiencing tensile forces and two experiencing compressive forces. Due to the combination and relationship of the two deflection beams and four strain gauges cooperatively associated in a common bridge circuit, the strain gauge G is functionally balanced by the circuit and the composite output signal of the circuit is corresponds exactly to the forces experienced by the deflection beam and the strain gauge and is symmetrical, i.e. the response to a deflection of beam D in a clockwise or counterclockwise direction with respect to the central axis of section B. balanced and accurate.

To further explain the invention, the display device is an electrical digital display adapted to display force in any desired units of force. For example, the device may be adapted to display kgm (foot pounds) of force, optionally 0. [
These forces are made to be accurately displayed in increments of 113 kgm (l/10 foot pounds).

It should be noted at this time that the digital display is significantly more accurate and reliable than a conventional hydraulic pressure gauge such as is commonly provided in prior art wrenches of the type concerned. be. In the case of conventional hydraulic pressure gauges, which are characterized by a calibrated dial card and a pivotably mounted display dial arm, the effective dimensions, number and/or spacing of the calibrations are significantly limited, parallax etc. The possibility of erroneous readings of the dial gauge as a result of this is large. In the case of the prior art wrench described above, the pressure gauge is calibrated to 3.33 kgm (25 foot pounds) of force, and due to parallax etc., the reliable reading of these dial dages is ±3.33 kgm (257 kgm). −) pounds) requires that incorrect readings of pounds) be tolerated.

In use, this digital reader eliminates the above-mentioned drawbacks found to exist in dial pressure gauges,
Accurate readings are guaranteed in specific increments, such as 1 foot pound.

The exact nature and shape of the electrical circuit E between the strain gauge G and the digital reader described above is not part of the invention;
Rather, it is a circuit designed and developed by others for the implementation of this wrench structure, which circuit is provided as the ultimate component included in the wrench structure. Accordingly, while the specific circuitry provided and used in putting together the present invention for implementation is shown schematically in FIG. It is not intended to be used as a service. The circuit E shown in FIG.
Suffice it to say that the circuitry used has proven to be highly effective and reliable in the implementation of the invention. The subject circuit, which in general terms is a bridge circuit or of the nature of a bridge circuit or equivalent to a bridge circuit, is referred to and claimed as the preferred bridge circuit for purposes of this disclosure.

The subject circuit E has a small, compact circuit board on which certain electrical components forming it are mounted. The circuit board is housed in a small container 50 attached to the front of the case 0, as shown in FIGS. 1 and 7. The digital reader of circuit E is mounted within the canister 50 and is visible through a window 51 in the front of the canister 50, as clearly shown in FIG. The strain gauge G, which is fixed to the flexible beam D of the part P, passes through a cavity 40 in the case 0 and a suitable opening or tunnel 53 drilled in the case C, as shown in FIG. It is coupled to the circuit board by a conductor 52 extending from the strain gauge.

In the illustrated form of the invention, the circuit's power supply H is mounted within the case 0. The power supply H is as shown in Figs. 6 and 7.
It is shown with a dry battery 60 engaged in a battery box 61 secured within an opening formed in one end of the case 0. The box 61 is permanently closed by a removable cover or lid 62.

According to the foregoing, the novel reaction component P having a pair of deflection beams associated with the strain gauge G and the electrical circuit E having a digital force display device add novelty to the entire disclosed wrench structure. It is clear that the present invention provides an improved torque wrench structure that constitutes a significant advance in torque wrench technology.

Although only one representative preferred form and implementation of the invention has been described, the invention is not limited to the specific details described, but is intended to be clear and patentable to those skilled in the art. It is intended to cover any modifications and/or variations within the scope.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the front, side and one end of the wrench structure of the present invention, FIG. 2 is a rear view of the wrench, and FIG. 3 is a rear view, side and one end of the reaction component. Perspective view,
FIG. 4 is a perspective view showing the front, other side and other end of the reaction part, and FIG. 5 is a view similar to that of FIG. 1. 6 is an enlarged cross-sectional view taken along line 5--5, FIG. 6 is a cross-sectional view taken along line 6-6, and FIG. The figure shows a cross-sectional view taken along the house line 8-8 in Fig. 7, and Fig. 9 shows a circuit diagram. B...body, 0...case, D...flexible beam, E... ...Electric circuit, G...Strain meter, Engineering...Display device, L...Lock pin, P...Reaction parts, R...
・Ratchet drive device, S...stop pin T...
Gear train, W...wrench, 10...input shaft, 11...
・Input worm gear, 14... Driven gear, 15...
Shaft, 16... Driven worm gear, 17... Output gear, 18... Tubular output shaft, 20... Drive spindle,
21... Operation sleeve, 32... Body opening, 3
3... Side edge, 40... Hollow space, 42... Center opening of lid plate.

Claims (20)

[Claims] (1) A reduction gear train having a case, an input shaft supported by the case within the case and having one end accessible outside the case, and an output shaft, the case being concentric with the output shaft. an external work-engaging component, a coupling device driveably coupling the work-engaging component to the output shaft, a central axis concentric with the output shaft, and an opening freely accommodating the coupling device. a reaction component having a body extending freely from said body and said case so as to engage a locking pin receiving device of an associated reaction structure associated with the component being acted upon by the wrench; a plurality of elongated locking pins in circumferentially and radially spaced relation thereabout; and a plurality of elongated locking pins circumferentially spaced about a central axis of the body and radially outwardly from the body. a plurality of elongated flexure beams projecting into the casing; a stop device between an outer end of the flexure beams and the casing for stopping circumferential rotation of the reaction component relative to the casing; a strain meter fixed to the deflection beam between and the body portion; a bridge circuit coupled to the strain meter for comparing resistances of the strain meter and transmitting a composite signal; and a digital readout device that displays a number corresponding to the force transmitted by the wrench through the work-engaging component of the wrench. (2) The case defines a cavity in which the reaction component is installed and has an opening adjacent to the body of the component, and the locking pin projects from the opening. Torque wrench structure described in section. 3. The reaction piece according to claim 1, wherein the reaction piece has two locking pins spaced radially outward from the axis of the body on diametrically opposite sides of the body. Torque wrench structure. 4. The torque wrench structure of claim 1, wherein the reaction piece has two flexure beams projecting radially outwardly from opposite sides of the body. (5) the reaction component includes two locking pins spaced radially outwardly from the axis of the body on each diametrically opposite side of the body; 2. A torque wrench structure as claimed in claim 1, having two protruding flexure beams. (6) the flexure beams have opposite sides laterally spaced apart from a radially extending longitudinal central axis thereof, one strain gauge on each opposite side of each beam; The torque wrench structure according to claim 1, which is fixed to. (7) the flexure beams have opposite sides laterally spaced apart from a radially extending longitudinal central axis thereof, one strain gauge on each opposite side of each beam; The torque wrench structure according to claim 3, which is fixed to. (8) the flexure beams have opposite sides laterally spaced apart from a radially extending longitudinal central axis thereof, one strain gauge being arranged on each opposite side of each beam; The torque wrench structure according to claim 4, which is fixed to. (9) the flexure beams have opposite sides laterally spaced apart from a radially extending longitudinal central axis thereof, one strain gauge on each opposite side of each beam; The torque wrench structure according to claim 5, which is fixed to. 10. The torque wrench structure of claim 1, wherein the stop device includes a stop pin engageable in the case and the deflection beam therebetween. 11. The torque wrench structure of claim 5, wherein the stop device includes a stop pin engageable between the case and the deflection beam. 12. The torque wrench structure of claim 6, wherein the stop device includes a stop pin engageable in the case and the flexure beam therebetween. 13. The torque wrench structure of claim 9, wherein the stop device includes a stop pin engageable in the case and the flexure beam therebetween. (14) The reduction gear train includes a driving worm gear on the input shaft, a pair of driven gears driven by the gears on driven shafts on both sides of the driving worm gear, and a driven worm gear on the driven shaft. and a central output gear driven by the driven worm gear on the output shaft between the driven worm gears. (15) the coupling device drivingly coupling the work-engaging component to the output shaft includes an elongated central spindle that freely engages a central opening of the output shaft; and a selectively reversible ratchet device drivingly engaged between the spindle and the spindle having a rotary drive coupling device for removably coupling the work-engaging component thereto. Torque wrench structure described in section. (16) The reduction gear train includes a driving worm gear on the input shaft, a pair of driven gears driven by the gears on driven shafts on both sides of the driving worm gear, and a driven worm gear on the driven shaft. and a central output gear driven by the driven worm gear on the output shaft between the driven gears, the coupling device drivingly coupling the work-engaging component to the output shaft. an elongated central spindle freely engaging a central opening in the output shaft; and a selectively reversible ratchet device driveably engaging the spindle and the output shaft therebetween; 2. The torque wrench structure of claim 1, further comprising a rotary drive coupling device for removably coupling the work-engaging component thereto. (17) The reduction gear train includes a driving worm gear on the input shaft, a pair of driven gears driven by the gears on driven shafts on both sides of the driving worm gear, and a driven worm gear on the driven shaft. and a central output gear driven by the driven worm gear on the output shaft between the driven gears, the coupling device drivingly coupling the work-engaging component to the output shaft. an elongated central spindle freely engaging a central opening in the output shaft; and a selectively reversible ratchet device driveably engaging the spindle and the output shaft therebetween; , a rotary drive coupling device removably coupling the work-engaging component thereto, the reaction component being spaced radially outwardly from the axis of the body on diametrically opposite sides of the body; The torque wrench structure according to claim 1, having two lock pins. (18) The reduction gear train includes a driving worm gear on the input shaft, a pair of driven gears driven by the gears on driven shafts on both sides of the driving worm gear, and a driven worm gear on the driven shaft. and a central output gear driven by the driven worm gear on the output shaft between the driven gears, the coupling device drivingly coupling the work-engaging component to the output shaft. an elongated central spindle freely engaging a central opening in the output shaft; and a selectively reversible ratchet device driveably engaging the spindle and the output shaft therebetween; , a rotary drive coupling device removably coupling the work-engaging component thereto, the reaction component being spaced radially outwardly from the axis of the body on diametrically opposite sides of the body; 2. A torque wrench structure as claimed in claim 1, having two locking pins, said reaction piece having two flexure beams projecting radially outwardly from opposite sides of said body. (19) The reduction gear train includes a driving worm gear on the input shaft, a pair of driven gears driven by the gears on driven shafts on both sides of the driving worm gear, and a driven worm gear on the driven shaft. and a central output gear driven by the driven worm gear on the output shaft between the driven gears, the coupling device drivingly coupling the work-engaging component to the output shaft. an elongated central spindle freely engaging a central opening in the output shaft; and a selectively reversible ratchet device driveably engaging the spindle and the output shaft therebetween; , a rotary drive coupling device removably coupling the work-engaging component thereto, the reaction component being spaced radially outwardly from the axis of the body on diametrically opposite sides of the body; the reaction piece has two flexure beams projecting radially outwardly from opposite sides of the body, the flexure beams having a radially extending longitudinal Claim 1 having opposite sides spaced laterally from its central axis in the direction, one strain gauge being fixed to each opposite side of each beam. Torque wrench structure as described. (20) The reduction gear train includes a driving worm gear on the input shaft, a pair of driven gears driven by the gears on driven shafts on both sides of the driving worm gear, and a driven worm gear on the driven shaft. and a central output gear driven by the driven worm gear on the output shaft between the driven gears, the coupling device drivingly coupling the work-engaging component to the output shaft. an elongated central spindle freely engaging a central opening in the output shaft; and a selectively reversible ratchet device driveably engaging the spindle and the output shaft therebetween; , a rotary drive coupling device removably coupling the work-engaging component thereto, the reaction component being spaced radially outwardly from the axis of the body on diametrically opposite sides of the body; the reaction piece has two flexure beams projecting radially outwardly from opposite sides of the body, the flexure beams having a radially extending longitudinal having opposite sides laterally spaced apart from its central axis in the direction, one strain gauge is fixed to each opposite side of each beam, and the stop device is connected to the case and 2. A torque wrench structure as claimed in claim 1 having stop pins engaging the flexure beams therebetween.