Wrench socket assembly
United States Patent [1 1 Gutshall Apr. 22, 1975 WRENCH SOCKET ASSEMBLY [75] Inventor: Charles E. Gutshall, Rockford, lll.  
 [73] Assignee: Elco Industries, Inc., Rockford, Ill.  
 [22] Filed: Nov. 23, 1973 [21] Appl. No.: 418,601  
 Primary E.\&#39;uminer-Donald G. Kelly Assistant Examiner-James G. Smith Attorney, Agent, or Firm-Wolfe, Hubbard, Leydig. Voit &amp; Osann, Ltd.  
 [57] ABSTRACT A wrench socket assembly adapted for turning a threaded fastening member includes a socket adapted to receive the fastening member and an insert member which includes a head held within a hole in the upper end of the body by a press fit and a base engaging the upper end of the socket to keep the insert member from moving upwardly within the socket as the fastener is tightened. A projection extending in an axial direction downwardly from the base of the insert member is telescoped into a corresponding opening within the head of the fastening member to hold the latter against wobbling as the member is tightened by the socket assembly. In alternate form of the invention, a boss extends downwardly from the base of the insert and axial opening extends through the boss and into the base to receive a projection extending upwardly from a central depression in the head of the fastener to also keep the socket assembly from wobbling on the head of the fastening member as the latter is being tightened.  
 10 Claims, 7 Drawing Figures WRENCH SOCKET ASSEMBLY BACKGROUND OF THE INVENTION This invention relates generally to a drive socket. more particularly to&#39; a twelve-point or double hexagonal drive socket of the type adapted for use in tightening a fastening member such as one which is adapted to be tightened to a predetermined torque. One particular fastener of this type is disclosed in a copending application Ser. No. 299.347. entitled Screw Adapted For Visible Inspection of Tightness and filed on Oct. 24. I972. The screw disclosed in that application includes a head with weakened corner portions which are folded smoothly into notches adjacent the weakened corner portions upon reaching the predetermined torque desired so that the socket used to tighten down the screw slips relative to the head to prevent the screw from being tightened beyond the predetermined torque. One form of a socket which may be used to tighten down a screw of this type is disclosed in Knudsen et al.. U.S. Pat. No. 3.273.430. Another patent which might be considered to be relevant to the prosecution of the patent application on the present invention is Reiland U.S. Pat. No. 3.763.725.  
 SUMMARY OF THE INVENTION The primary object of the present invention is to providea new and improved socket which is adapted particularly for use in tightening a torque limited fastener of the above mentioned type and which during tightening is kept from wobbling on the head of the fastener. More particularly. it is an object of the present invention to accomplish the foregoing through the provision of a novel insert member which is telescoped into the socket of the assembly and which includes a unique connection constructed so as to mate with a portion of the fastener to keep the socket from wobbling on the head of the fastener.  
  These and other objects and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.  
 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of a wrench socket assembly embodying the novel features of the present invention with a portion of the socket broken away and shown in cross section for clarity of illustration.  
  FIG. 2 is an elevational view of the assembly with portions thereof broken away and taken in cross section.  
  FIG. 3 is a cross-sectional view taken substantially along line 3-3 of FIG. 2.  
  FIG. 4 is an enlarged cross-sectional view taken substantially along line 4-4 of FIG. 2.  
  FIG. 5 is an elevational view similar to FIG. 2 but showing an alternative embodiment of the invention.  
  FIG. 6 is a view taken substantially along line 6-6 of FIG. 5.  
  FIG. 7 is a perspective view of the fastener to be used in conjunction with the-alternative embodiment of the invention.  
 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in the drawings for purposes ofillustration,  
 the present invention is embodied in a wrench socket assembly which is particularly adapted for use in tightening and loosening a torque limiting fastening member such as the screw 16 shown in FIG. 1 and more fully described in the above-mentioned copending application. Briefly. however. the screw includes a head 17 integrally formed on the end of a threaded shank l9 and having corner portions 20 weakened by adjacent notches 21 to a predetermined strength which is correlated with a predetermined torque to which the screw is to be tightened in a workpiece (notshown). The weakened corner portions are adapted for engagement by the assembly to turn the screw and. as the screw is tightened to the predetermined torque in the workpiece. the weakened corner portions give way without breaking loose and are folded over into the notches by the assembly. Once the weakened corner portions are folded into the notches, the assembly then slips around the head and thus the screw is kept from being excessively tightened in the workpiece.  
  The predetermined torque to which the screw 16 is tightened in the workpiece depends in part upon the thickness of the head 17 of the screw at the weakened corner portions 20. For instance. with a thinner head. less torque is required to fold over the weakened corner portions than is required with a thicker head. It has been found that when using thin head torque limiting screws of the foregoing type. the thin head of the screw has a tendency to cock within a conventional driver socket (not shown) so as to cause the socket to wobble on the head during tightening and loosening.  
  The present invention contemplates a provision of a novel insert 23 within the wrench socket assembly 15 so as to keep the assembly from wobbling on the fastening member or screw 17 as the latter is turned during tightening or loosening of the member within a workpiece. For this purpose. the assembly includes a body 24 with the insert member captivated within a drive socket 25 in the body. An opening 26 of predetermined width within either one of the insert or fastening members receives a slightly smaller projection 27 which is formed on the other member when the fastening member is inserted into the socket. With this arrangement. the fastening member is kept from being cocked within the socket to avoid wobbling within the socket 25 as the fastening member is turned to be tightened or loosened in the workpiece.  
  As shown more particularly in FIG. 1, the body 24 of the socket assembly 15 is generally cylindrical in shape and includes an enlarged upper section 29, a smaller diameter lower section 30 and a tapered portion 31 (FIG. 2) extending between the two sections. A square drive hole 33 is formed in the upper section to receive the connector of a driver (not shown) and apertures 34 through opposite sides of the upper section are adapted to receive the usual spring loaded balls on the drive connector to releasably lock the body 24 of the assembly with the driver. I  
  In the lower section 30 of the body 24 the socket 25 is defined by a generally cylindrical side wall 35 which is concentric with the axis of the body and comprised of a series of alternating protrusions 36 and recessions 37 (see FIG. 4) which respectively extend toward and away from the axis of the body in a generally radial directionso as to mate with the head 17 of the screw 16 with a driving fit. Herein. the socket 25 is of the double hexagonal type and thus includes 12 of the protrusions and l2 of the recesses with each of the protrusions and recesses extending in an axial direction along the full width of the side wall 35. More particularly. each of the protrusions is defined by a convex surface curving generally toward the axis of the body and each of the recesses as defined by a concave surface curving generally away from the axis of the body. The diameter of the socket as measured between the recesses is approximately percent greater than the diameter of the socket as measured between the protrusions so that the weakened corner portions of the screw are engaged by and folded into the notches by the protrusions as the screw is tightened in the workpiece. In addition, the radius of curvature of each of the protrusions is approximately twice that of the radius of curvature of each of the recesses so that the weakened corner portions are folded smoothly into the notches without causing excessive wear between the protrusions and the head of the screw.  
  The upper end of the socket is defined by an end wall 39 formed integrally with the side wall and extending in a radial direction from the side wall toward the axis ofthe body. A circular hole 40 through the end wall communicates between the drive hole 33 and the socket and is of a predetermined diameter so as to receive the insert member 23 with a press fit.  
  In the exemplary form of the invention, the insert member 23 includes a generally cylindrical head 41 having a diameter substantially equal to the predetermined diameter of the hole 40 and a base 43 integrally formed with one end of the head. Herein, knurls 44 are formed in the side of the head 41 so as to bite into the edges of the hole 40 and hold the insert within the body. More particularly, the base is generally circular in shape and projects radially outwardly beyond the side of the head so that the upper side 45 of the base engages the end wall 39 of the socket when the head of the insert is fully telescoped into the circular hole. Thus, the insert supported against moving upwardly within the socket 25 by the end wall.  
  In the form of the invention shown in FIGS. 1 through 4, the projection 27 is generally cylindrical in shape and formed integrally with the base 43 of the insert 23, projecting downwardly thereof in a generally axially direction. The opening 26 is formed in the head 17 of the screw 16 and is generally circular in crosssection extending into the head of the screw alongthe central axis of the screw. More particularly, the diameter of the opening 26 is slightly greater than the diameter of the projection so that the latter is free to turn within the screw during tightening. Accordingly, when the screw is inserted into the socket 25, the projection mates with the opening 26 to center the screw within the socket with the sides of the projection engaging the sides of the opening to hold the head from becoming cocked within the socket so as to prevent the latter from wobbling on the head of the screw as the latter is being tightened.  
  A slightly different form of the invention is illustrated in FIGS. 5 through 7 with parts corresponding to the first form of the invention indicated by the same but primed reference numerals. In this form of the invention, the opening 26&#39; is formed in the insert 23&#39; rather than in the head 17 of the screw 16&#39; and the projection 27&#39; is formed on the head of the screw rather than on the insert. More particularly, the insert 23&#39; includes an annular boss projecting axially in a downward direction from the base 43&#39;. The opening 26&#39; is formed completely through the boss and extends upwardly into the base of the insert. Formed in the head of the screw is a central depression 51 having a diameter somewhat larger than the diameter of the boss so as to receive the boss when the screw 17&#39; is inserted into the socket 25&#39;. Extending upwardly from the center of the depression is the cylindrical projection 27&#39; which is received within the opening 26 in the insert member when the screw is inserted into the socket so as to keep the latter from wobbling on the head of the screw as the screw is tightened in the workpiece.  
  From the foregoing, it is seen that the novel insert 23 of the wrench socket assembly 15 of the present invention enables the socket assembly to be used with the torque limited screws 16 and without wobbling on the head 17 of the screw during tightening. Herein, the insert may take two forms, one with the projection 27 formed on the insert and with the opening 26 formed in the head of the screw and the other with the projection 27&#39; being formed on the head 17 of the screw 16&#39; and the opening 26&#39; being formed in the insert 23&#39;.  
 1 claim:  
  1. A wrench socket assembly in combination with a threaded fastening member adapted to be received within and turned by said assembly, said assembly comprising a body having a central axis, a socket formed in said body along said axis, a side wall defining the periphery of said socket within said body and extending in a generally axial direction, an end wall of said socket formed integrally with said side wall and extending in a generally radial direction from said side wall toward the axis of said body, said side wall comprising a series of alternating protrusions and recesses respectively extending toward and away from the axis of said body in a generally radial direction so as to mate with said fastening member with a driving fit, a hole formed in said end wall, an insert member mounted within said hole and extending into said socket, means connecting said insert member with said fastening member to keep said body from wobbling on said fastening member while still permitting relative rotation between said insert member and said fastening member, said means including an opening of predetermined width formed in one of said members, and a projection having a width slightly smaller than said predetermined width and being formed on the other one of said members so as to mate with said opening when said fastening member is inserted into said socket.  
  2. The combination therefor defined by claim 1 wherein said hole is generally circular in shape having a predetermined diameter, said insert member comprising a generally cylindrical head having a diameter substantially equal to said predetermined diameter of said hole to telescope within said hole with a press fit, a circular base projecting radially outwardly from one end of said head and having an upper side engaging said end wall of said socket.  
  3. The combination therefor defined by claim 2 wherein said opening is generally circular in shape, said projection being generally cylindrical in shape.  
  4. The combination therefor defined by claim 3 with said projection being formed integrally with said insert and extending in an axial direction from the lower side of said base opposite said head.  
  5. The combination therefor defined by claim 3 with said opening being formed in the lower side of said base opposite said head.  
  6. The combination therefor defined by claim 5 with said insert member including an annular boss projecting axially from said base in a direction opposite said head, said opening extending upwardly through said boss and into said base, said fastening member including an upper end portion adapted to be received within said socket, a central depression formed in the top of said upper end portion. said projection extending upwardly from the center of said depression.  
  7. The combination therefor defined by claim 3 with said side wall defining said socket being generally cylindrical in shape and including twelve of said protrusions and twelve of said recesses. each of said protrusions having a convex surface curving toward the axis of said body, each of said recesses having a concave surface curving away from the axis of said body.  
  8. The combination therefor defined by claim 7 wherein the diameter of the socket as measured between said recesses is approximately ten-percent greater than the diameter of the socket as measured between said protrusions, the radius of curvature of each of the protrusions being approximately twice that of the radius of curvature of each of said recesses.  
  9. A wrench socket assembly adapted to receive a threaded fastening member having a head with an upwardly extending cylindrical projection of predetermined diameter said assembly being adapted to turn said fastening member and comprising a body having a central axis, a socket formed in said body along said axis, a side wall defining the periphery of said socket within said body and extending in a generally axial direction, an end wall of said socket formed integrally with said side wall and extending in a generally radial direction from said side wall toward the axis of said body, said side wall comprising a series of alternating protrusions and recesses respectively extending toward and away from the axis of said body in a generally radial direction so as to mate with said fastening member with a driving fit, said side wall defining said socket as being generally cylindrical in shape. each of said protrusions having a convex surface curving toward the axis of said body, each of said recesses having a concave surface curving away from the axis of said body, the diameter of the socket as measured between said recesses being approximately ten percent greater than the diameter of the socket as measured between said protrusions and the radius of curvature of each protrusion being approximately twice that of the radius of curvature of each of said recesses, a circular hole formed in said end wall, an insert member mounted within said hole with a press fit and extending into said socket, and a circular opening formed in the lower end of said insert member and having a diameter slightly larger than said predetermined diameter so as to mate with said projection when said fastening member is inserted into said socket thereby to keep said body from wobbling on said fastening member as the latter is being turned.  
  10. A wrench socket assembly adapted to receive a threaded fastening member having a head with a circular opening formed in the upper surface thereof, said assembly being adapted to turn said fastening member and comprising a body having a central axis, a socket formed in said body along said axis, a side wall defining the periphery of said socket within said body and extending in a generally axial direction, an end wall of said socket formed integrally with said side wall and extending in a generally radial direction from said side wall toward the axis of said body. said side wall comprising a series of alternating protrusions and recesses respectively extending toward and away from the axis of said body in a generally radial direction so as to mate with said fastening member with a driving fit, said side wall defining said socket as being generally cylindrical in shape, each of said protrusions having a convex surface curving toward the axis of said body. each of said recesses having a concave surface curving away from the axis of said body, the diameter of the socket as measured between said recesses being approximately ten percent greater than the diameter of the socket as measured between said protrusions and the radius of curvature of each protrusion being approximately twice that of the radius of curvature of each of said recesses, a circular hole formed in said end wall, an insert member mounted within said hole with a press fit and extending into said socket, and a cylindrical projection formed on said insert and having a diameter slightly smaller than the diameter of said opening, said projection depending from said insert so as to mate with said opening when said fastening member is inserted into said socket thereby to keep said body from wobbling on said fastening member as the latter is being turned.