US 3662628 A
A torque release adapter comprising a receptacle and rigid plate rotatably mounted therein with confronting surfaces normal to the axis of rotation, said surfaces containing recesses in which are mounted bearing members, and means for yieldably applying pressure to the parts to constrain the bearings to said recesses to transmit torque from one part to the other, said yieldable means being yieldable to a torque in excess of a predetermined adjustable amount to permit the parts to separate so that one part rides over the bearing members relative to the other part a distance corresponding to the distance between recesses and then become re-engaged with the bearing members.
Description (OCR text may contain errors)
[ 51 May 16, 1972  TORQUE RELEASE ADAPTER Lawrence S. Schnepel, 250 Goodman Hill Road, Sudbury, Mass. 01776  Filed: Apr. 20, 1970  Appl.No.: 30,043
Related U.S. Application Data  Continuation-impart of Ser. No. 860,23l, Sept. 23,
on t N 0.0.0..
2,733,622 2/l956 Evans ..8l/52 4 FOREIGN PATENTS OR APPLICATIONS 473,202 9/1914 France ..l5l/2l C Primary Examiner-James L. Jones, Jr. Attorney-Roberts, Cushman & Grover [5 7] ABSTRACT A torque release adapter comprising a receptacle and rigid plate rotatably mounted therein with confronting surfaces normal to the axis of rotation, said surfaces containing recesses in which are mounted bearing members, and means for yieldably applying pressure to the parts to constrain the bearings to said recesses to transmit torque from one part to the other, said yieldable means being yieldable to a torque in excess of a predetermined adjustable amount to permit the parts to separate so that one part rides over the bearing members relative to the other part a distance corresponding to the distance between recesses and then become re-engaged with the bearing members.
10 Claims, 17 Drawing Figures TORQUE RELEASE ADAPTER This application is a continuation-in-part of application Ser. No. 860,231, filed Sept. 23, 1969, now abandoned.
BACKGROUND OF THE INVENTION Torque limiting devices are used for many purposes, two such devices being shown in US. Pat. Nos. 3,012,456 and 3,137,187, in the form of torque wrenches designed to enable limiting the torque which may be applied in tightening nuts, screws, bolts, and the like. The purpose is to insure the same degree of tightness for all of the fastening elements applied thereby and/or to prevent its exceeding the shearing limit of the fastenings. The devices as disclosed in the aforesaid patents are complete implements in and of themselves and their geometry is such that it is difficult to apply a torque uniformly, 'to ascertain the point of release and to insure freedom from applying a torque in excess of that which it is intended to release.
SUMMARY This invention has for its purpose to provide an adapter which may be employed in conjunction with torque multiplying tools, socket wrenches, open end wrenches and the like as mentioned above, to limit the torque which may be applied; to provide a device which may be set to function at a predetermined torque and which may be adjustable to provide for a range of torques; to provide a device which is small in working radius and axially short enough to minimize bending couples which tend to reduce efficiency and to be dangerous to the user; to provide a device which efficiently applies the torque up to the maximum amount for a given adjustment; to provide a device which is free of excess overtravel; to provide a device which cannot be manipulated to apply a torque in excess of that for which it is set; and to provide a device which is light in weight, relatively inexpensive to manufacture, internally resistant to wear, substantially frictionless and wholly sealed against damage.
As herein illustrated, the device comprises a receptacle embodying a chamber for receiving torque release mechanism, said chamber having a side wall-closed at one end and open at the other, a first shaft fixed to the outer side of the end wall, a second shaft, a rigid disc fixed to one end of the second shaft, said second shaft and disc being mounted in the receptacle with the disc next to the inner side of the end wall, said disc and end wall providing rigid confronting faces and containing a plurality of regularly spaced recesses located at equal radial distances from the center, a corresponding number of bearings supported between the disc and end wall in the recesses, and means yieldably holding the bearings between the disc and end wall comprising a plurality of annular spring members mounted on the second shaft against the disc and an annular nut mounted on the second shaft against the spring members, said nut being threaded into the open end of the receptacle and rotatable therein to adjust the pressure of the spring members against the disc. In one form of the device the recesses are of circular section to receive ball bearings and the portions thereof in one of the confronting surfaces are deeper than those in the other, the portions of greater depth being at least greater than one-half the diameter of the balls. Optionally, the recesses may be of tapering configuration with larger ends adjacent the periphery and the smaller ends adjacent the center and the bearings in this case are frusto-conical roller bearings. The means yieldably holding the disc and end wall engaged with the bearings are concave annular spring washers placed face-to-face. An annular thrust bearing is interposed between the outer side of the rigid disc and the first of the washers, a sleeve thrust bearing is mounted in the nut around the second shaft and optionally there is means for locking the nut in a predetermined position of adjustment.
The invention will now be described in greater detail with reference to the accompanying drawings wherein:
FIG. 1 is an elevation of the torque release adapter;
FIG. 2 is a plan view of FIG. 1 as seen from the top;
FIG. 3 is a plan view of FIG. 1 as seen from the bottom;
FIG. 4 is an elevation of the adapter, partly in section, to much larger scale;
FIG. 5 is an exploded view of the adapter showing the several components making up the unit, some of which are in elevation or partly in elevation and partly in section and others of which are in section;
FIG. 5a is a view taken on the line 5a-5a of FIG. 5;
FIG. 5b is a view taken on the line 5b-5b of FIG. 5;
FIG. 5c is a view taken on the line 5c-5c of FIG. 5;
FIG. 6 is a view partly in section of an alternative form of closure cap for the unit;
FIG. 6a is a view partly in section of a modification of the cap shown in FIG. 6;
FIG. 6b is a plan view of FIG. 6a;
FIG. 7 is a fragmentary section of the structure designed to operate with roller bearings in place of ball bearings;
FIG. 7a is a plan view of the roller bearing assembly shown in FIG. 7;
FIG. 8 is an elevation of the adapter provided with a handle to enable easily placing it in a position for use;
FIG. 9 is a fragmentary vertical section through still another form of cap;
FIG. 10 is an elevation as seen from the right side of FIG. 9; and
FIG. 1 l is a plan view of FIG. 9.
Referring to the drawings, the torque release adapter comprises a receptacle 10 within which is mounted torque release mechanism 12. A closure cap 14 confines the torque release mechanism 12 in the receptacle and optionally provides for adjustment for the amount of the torque which will be transmitted by the adapter.
The receptacle 10, as shown in FIG. 4, is of circular crosssection having a cylindrical side wall 15 closed at one end by an end wall 16 and open at the other end and providing within the wall a cylindrical chamber 18. The end wall 16 has a portion 20 of reduced diameter and contains a centrally located opening 24 of non-circular configuration for receiving a tool or other implement for applying rotation thereto or for receiving a nut or other fastening to which a turning couple is to be applied through the adapter. The opening 24 extends through the end wall to the interior of the chamber 18, its axis coinciding with the axis of the chamber and at its inner end is enlarged diametrically to provide a shallow circular recess 26. The open end of the receptacle is provided at its inner side with threads 28. Knurling K (FIG. 1) and/or a handle H (FIG. 8) may be provided to facilitate placing the adapter in position for use.
In accordance with the invention the surface 16a of the end wall 16 is provided with a plurality of recesses 30 arranged in a circle about the axis of the receptacle close to the wall 15, the recesses being hemispherical in configuration for receiving ball bearings b. As herein illustrated, there are twelve such recesses spaced regularly about the axis of the receptacle.
Within the receptacle there is mounted torque release mechanism 12 which comprises a rigid circular disc 32 corresponding substantially in diameter to the inside diameter of the receptacle but enough smaller to turn freely therein, which has in its lower surface 34 a plurality of recesses 36 corresponding in a number to the recesses 30. The recesses 36 are located at the same radial distance from the axis of the disc and of the receptacle as are the recesses 30 from the axis of the receptacle. The disc 32 is fixed to one end of a shaft 38 which extends axially therefrom through the open end of the receptacle and has a reduced portion 40 extending beyond the open end of the receptacle which is of non-circular cross-section containing a spring-pressed ball 42. The shaft 38 has a shoulder 38a next to the disc on which is mounted an annular roller bearing assembly 44 and provides support outwardly of the bearing for a washer 46 and two pairs of oppositely dished spring washers 48 and 50. The closure cap 14 is in the form of a nut 52 provided with externally formed threads 54 for engagement with the threads 28 at the inner side of the receptacle and is provided with a neck 56 containing diametrically disposed notches 58 for receiving a spanner wrench by means of which it may be turned to screw it into the open end of the receptacle against the spring washers 44 and 50 and to apply varying degrees of pressure thereto so as to provide for the transmission of different torques. The closure cap contains a center opening 60 through which the upper end of the shaft 38 extends and is rotatably supported by a sleeve bearing as- Instead of employing ball bearings b as shown in FIGS.
through 5b, roller bearings r may be employed as shown in FIGS. 7 and 7a. The roller bearings r shown are longitudinally conical and the surfaces 16a, 34 are provided with conical recesses 66 and 68 for receiving them. The roller hearing assembly 70 for holding the roller bearings r is shown in FIG. 7a.
Preferably, the recesses 30 or 66 in the surface 16a of the receptacle are made deeper than the recesses 36 or 68 in the surface of the disc 32 so that the bearing members remain in the recesses 30, 36 and the disc travels over the bearing members as it rotates relative to the receptacle, thus the wear is confined for the most part to the surface 34 of the disc since the only part that need be made of a hardened steel is the disc or the surface of the disc. The receptacle may be made of a mild steel with a material saving in cost.
Modified closure caps are shown in FIGS. 6, 6a and 6b designed to be locked in place after the desired adjustment has been made. The cap 14a shown in FIG. 6 comprises a nut 52a in every respect like that shown in FIGS. 4 and 5, except that it contains a slot 0 part way through it dividing the nut into upper and lower parts 72, 74. A screw 92 is threaded through a threaded hole 90 in the upper part 72 against the lower part 74 and by forcing the screw against the lower part 74 after the nut has been turned to obtain the desired torque release point the nut may be locked at this position.
Optionally, a cap 14b may be employed comprising two rings 72a and 74a containing openings 76a and 78a through which the shaft 40 extends and within which are mounted sleeve bearing assemblies. The upper ring 72a is provided with a neck 56a containing notches 58 by means of which the assembly may be turned to make an adjustment and the lower ring 74a is connected to the upper ring so as to turn therewith by means of diametrically disposed pins 82 having their lower ends fixed in the ring 74a and their upper ends slidable in holes in the upper ring. The two rings have external threaded portions 86 and 88 for threaded engagement with the upper end of the receptacle and the upper ring contains diametrically disposed threaded holes 90a in which there are mounted screws 92a. The cap is mounted in the upper end of the receptacle and turned therein until the desired degree of resistance to torque is obtained whereupon the screws 92a are rotated to force the rings away from each other thereby binding their threads 86 and 88 against the threads 28 at the upper end of the receptacle and thus locking the assembly in place.
A third form of locking cap 140 is shown in FIGS. 8, 9 and 10, comprising an annular nut 100 containing an internal opening 102, external threads 104 and diametrically disposed notches 106-106 to enable turning it in the receptacle. According to this form, holes 108-108 are drilled at diametrical positions into the nut from the top side downwardly toward the bottom side but terminating short of the bottom side. These holes 108-108 are started in the top side with their outside diameter intersecting the threaded exterior surface of the nut so as to provide openings 110-110 in the threaded surface and extend downwardly and divergently away from the center of the nut. The openings 110-110 in the side accordingly taper from the top to the bottom (FIG. 10), increasing in width toward the bottom. The openings -110 expose the threaded interior of the receptacle 15 to the interior of the holes 108-108 and set screws 112-112 are screwed into the holes 108-108 into threaded engagement with the threads 28 on the. interior of the receptacle 15. The holes 108-108 themselves have smooth interior surfaces and when the set screws 112-112 are drawn down by engagement with the threads 28 the sloping surfaces of the holes wedge the screws against the threaded interior of the receptacle and hence lock the nut in place. An angle of approximately 6 is suitable for obtaining the required wedging action and locking of the nut. 4
The adapter is packed with a lubricant and to keep dirt out of the interior a flat sealing disc 94 (FIGS. 4 and 5) is set into the recess 26 and is held therein by a spring 96 disposed between it and a recess 98 in the lower side of the plate 32.
If desired the adapter may be calibrated so that by turning the closure cap 14 a predetermined number of turns relative to an index mark the point of torque release may be preset.
In operation the adapter will transmit torque applied until the upward component of force exceeds the spring pressure exerted by the spring washers on the disc which tend to hold it engaged with the bearing members whereupon the disc yields upwardly and rides over the bearing members relative to the receptacle, the bearing members remaining in the recesses in the receptacle. When the disc has moved a distance corresponding to the distance between the bearing members it tends to return to its undisplaced position. If a torque continues to be applied which exceeds the spring pressure the disc will continue to ride over the bearing members; however, each time the recesses therein come opposite the bearing members there will be an audible click indicating that the disc is rotating relative to the receptacle and that the maximum torque for which the unit is set has been reached. During the rotation the bearing members rotate about their own centers in the recesses in the receptacle. As indicated heretofore the deeper recesses may be made in the disc rather than the receptacle if desired.
I lclaim: v
1. A torque release adapter comprising a receptacle embodying a chamber for receiving torque release mechanism, said chamber having a side wall closed at one end by an end wall and open at the other end, said end wall containing centrally thereof an axially extending opening of rectangular configuration and at the junction of said rectangular opening and the interior a centrally located circular recess of larger cross section than the rectangular opening, saidside wall at the open end containing interior threading, a shaft comprising axially aligned portions of different cross-section and at one end an integral head having a flat circular face perpendicular to the axis thereof, said portions of different cross-section decreasing in area from the portion next to the head which is the largest toward its distal end and comprising proximal intermediate and distal portions, said distal portion being of rectangular cross-section, a nut containing a centrally located opening adapted to receive the intermediate portion of the shaft with a clearance therebetween, a sleeve-like needle bearing assembly mounted on the distal portion within the clearance about the shaft, said assembly being force-fitted into the opening and having an axial length corresponding to the thickness of the nut, said nut having a fiat inner side and a kerfed outer side and being exteriorly threaded peripherally for threaded engagement with the interior threading at the open end of the wall, said nut being adjustable to support the shaft within the chamber with the head confronting the inner side of the end wall, said confronting surface of the head and end wall containing a plurality of uniformly spaced recesses adapted to receive balls, means yieldably holding the balls in said recesses comprising spring washers disposed on the intermediate portion of the shaft between the nut and the head of the shaft, antifriction means situated between the head and spring washers comprising a flat annular washer and an annular needle bearing disposed about the proximal portion of the shaft, said needle bearing being confined between the spring washers and the head, said nut sealing the opening at the open end of the wall, a flat disc mounted in said circular recess, and a coiled spring situated between the head and the disc holding said disc in sealing engagement with the inner end of said rectangular opening.
2. A torque release adapter according to claim 1, wherein the recesses in the planes of the faces taper, the wider ends being adjacent the periphery of the faces and the narrower ends adjacent the centers of the faces, and the bearing members are frusto-conical in shape.
3. A torque release adapter according to claim 1, wherein the nut comprises concentric parts connected for rotation in unison but separable in a direction along their common axis of rotation, and screws threaded through one part in engagement with the other part by means of which the parts may be forced away from each other to bind their respective threads against the threads of the receptacle.
4. A torque release adapter according to claim 1, wherein the nut contains a slot part way through it parallel to its end faces, a threaded hole through the portion of the nut at one side of the slot and a locking screw threaded into the threaded hole against the portion of the screw at the other side of the slot, said locking screw being adapted by rotation to force the parts at opposite sides of the slot away from each other thereby to bind the thread on said parts against the threads of the receptacle.
5. A torque release adapter according to claim 1, wherein a handle is fixed to said receptacle to extend radially therefrom.
6. A torque release adapter according to claim 1, wherein said annular nut contains diametrically disposed holes entering the top and extending downwardly at angles divergent to the axis of the nut, said holes at the top intersecting the threaded exterior of the nut and providing openings therein, and a set screw situated in each of the holes in threaded engagement with the threaded interior of the receptacle exposed to the interior of the hole through said openings.
7. A torque release adapter according to claim 6, wherein the upper ends of the holes are substantially tangent to the pitch circle of the threaded interior of the receptacle.
8. A torque release adapter according to claim 6, wherein said openings taper from a minimum width at the top to a greater width at the bottom.
9. A torque release adapter according to claim 6, wherein said holes terminate short of the bottom of the nut.
10. A torque release adapter according to claim 1, wherein said holes have smooth interior surfaces.