DEVICE FOR A TORQUE WRENCH

Abstract: The present invention relates to a device for coupling a torque handle (100, 200) to a socket and for limiting the torque applied to the socket by the handle characterised in that the device comprises a body (10) connectible to said handle and having a substantially cylindrical portion (11) at one end thereof; a torque limiting clutch (70) for transmitting torque from the handle to the socket; means (80) coupling the clutch (70) to the body (10) and applying force to the clutch to maintain the clutch in an engaged attitude; a housing (50) for said clutch (70), the housing being telescopically coupled to the body (10) such that rotation of the housing and the body relative to one another displaces the housing and the body towards or away from one another to adjust the force applied to the clutch by said means (80); and control means (30) movable between two positions, in a first of which said housing (50) and said body (10) are freely rotatable relative to one another and in the second of which positions said housing and said body are locked non-rotatable relative to one another.

Description: Device for a Torque Wrench This invention relates to a device for a torque wrench for coupling a torque handle to a socket. The conventional torque wrench is generally provided with no torque indicating means and is prone to distorting or breaking a nut of an article when the torsion applied thereto is too great. Adversely, the nut loosens and becomes insecure when the torsion applied is insufficient. For example, spark plugs and various nuts and bolts used in automobiles and motorcycles, and fittings for home electrical appliances require tightening to a specific torque value. One known type of torque wrench has an indicating disc on a handle thereof and an indicator on a rectangular plug thereof. However, it is considerably bulky and is inconvenient to use. In addition, it requires close attenti to be paid to the indicating disc and the indicator thereof while being used to ensure that the desired torque is not exceeded. In this case, only a skilled operator can make good use of the torque wrench. An object of the present invention is to provide an improved socket joint for a torque wrench. The present invention provides a device for coupling a torque handle to a ocket and for limiting the torque applied to tie socket by the handle characterised in that the device comprises a body corine tible to said handle and having a substantially cylindrical portion at one end thereof; a torque limiting clutch for transmitting torque from the handle to the socket; means coupling the clutch to the body and applying force to the clutch to maintain the clutch in an engaged attitude; a housing for said clutch , the housing being telescopically coupled to the body such that rotation of the housing and the body relative to one another displaces the housing and the body towards or away from one another to adJust the force applied to the clutch by said member ; and control means movable between two positions, in a first of which said housing and said body are freely rotatable relative to one another and in the second of which positions said housing and said body are locked¯non-rotatable relative to one another. The present invention is further described hereinafter, by way of example, with reference to the accompanying drawings; in which: Figure 1 is an exploded perspective view showing a preferred embodiment of the present invention; Figure 2 is a longitudinal section through the preferred embodiment of Fig. 1; Figure 3 is a longituAinal section through a second embodiment according to the present invention; Figure 4 is a perspective view showing a torque wrench according to this invention; Figure 5 is a perspective view showing a further torque wrench according to this invention; and Figure 6 is an exploded perspective view showing a second form of clutch for a joint according to this inventio Figure 1 shows a preferred device according to this invention comprising a body 10, a bolt 20, a rectangular plug 60, a clutch housing in the form of a casing 50, a clutch 70, a spring 80, a compressing ring 40, a controlling ring 30 and a positioning nut 90. The body 10 is in the form of a cylinder having a cylindrical portion or chamber 11 situated at its lower end as seen in Fig. 1 so as to receive the clutch casing 50. Situated adjacent the opposite, upper end of the chamber 11 is a screw-threaded axial blind bore 12 which engages with one end of the bolt 20 a plurality of small screw-threaded radial bores 13 are provided in the body 10 opening into the bore 12 for receiving screws 25 which secure the bolt 20 in position. A plurality of through holes IC are provided in the wall 15 of the chamber 11 so as to receive a plurality of beads 17 each having a diameter greater than the thickness of the wall 15 of the chamber 11. The upper end of the body 10 is provided with an axial socket 18 of rectangular cross-section so as to receive a rectangular plug of a torque wrench (not shown). The outer periphery of the body 10 is engraved with a plurality of lines 19 corresponding in number to recesses in the form of guiding flutes 53 of the clutch casing 50 and indicating lines and symbols 55 engraved on the outer wall of the casir 50. One end of the bolt 20 engages in the bore 12 as described above; the other end thereof engages in a screw, threaded axial bore-93 in the positioning nut 90. The controlling ring 30 is a sleeve-like fit around th outer wall of the chamber 11 and at each end has a respectiv annular recess 31, 32 in the formed of increased internal diameter portions so as to protect wholly the compressing ring 40 and the outer wall of the body 10 in part. A protruding pin 33 is provided on the cavity ring 32 and engages in an arcuate groove 42 in an upper surface 41 of th compressing ring 40 so that rotation of the controlling ring 30 relative to the ring 40 is limited. The outer wall of the controlling ring 30 is provided with an indicati means 34 showing the states of "ON" and "OFF" each of which can be b3'ouLht into a]igr.ment with an arrow on the body 10 to indicate whether torsion is "ole" or "OFF". The inner wall 35 of the ring 30 is provided with a plurality of longitudinal grooves 36 to receive the beads 17. A slanting rim of each groove 36 facilitates insertion and removal of said beads 17. The inner diameter of the compressing ring 40 is equal to the outer diameter of the chamber 11 so that said compressing ring 40 is a tight fit over the body 10. The outer diameter of the ring 40 is somewhat smaller than inner diameter of the recess 32 of the ring 30 so as to enable the controlling ring 30 to rotate freely. The clutch casing 50 is a hollow cylindrical tube provided with a radially inwardly directed annular flange 51 at a lower end of its inner wall to receive the rectangular plug 60 and clutch 70. The positioning nut 90 is secured to the clutch casing 50 by inserting one or more pins 95 through holes 52 and 92 in the casing 50 and positioning nut 90 respectively. The spring 80 is positioned between the bolt 20 and clutch 70. h plurality of guiding flutes 53 are provided on the outer wall of the casing 50 so as to partially receive the beads 17. A plurality of indicating lines and symbols 55 are engraved on the outer wall thereof to indicate the strength of torsion applied thereto. The plug 60 rests against the protruding ring 51 with its rectangular portion projecting at worse end and is designed to connect with a socket of an article. The other end of the plug 60 is formed as one clutch member with teeth to engage with teeth 71 on a second clutch member 71. The clutch members 71 as shown in Figure 1 have symmetrical teeth. Figure 6 shows a further preferred embodiment of the clutch; one contacting face thereof is provided with a plurality of protrusions 711 while another face thereof is provided with several cavities 712 corresponding to the protrusions 711. A locating means 72 is situated to positic said spring 80 on the clutch. The positioning nut 90 has a cylindrical outer wall 91 provided with two said circular holes 92 to enable it to be secured to the clutch casing 50 as described hereinbefore The inner wall of the nut 90 is provided with the bore 93 as previously mentioned permitting movement of the clutch casing 50 with respect to the body 10 so as to adjust the tension of the spring 80 and to adjust the torsion applied by the socket joint. Figures 2, 3 and 4 show how the socket joint of this invention is fitted to a torque wrench. A plug of a torque wrench 100 is inserted in the rectangular socket 18. The rectangular plug (60 then engages with a fs(,cket of an article requiring torsion. \'brn the controlling ring 30 is rotted to t1le indicating meanns 34 bring the "OFF"iridicating means 34 adjacent the arrow on tie body 10 the beads 17 which are held in engagement in the flutes 53 by the inner wall of the ring 30 will engaged in the grooves 36 of the controlling ring 30. This allows the beads to rise out of the flutes 53 (Fig. 3) and allows rotation of the body 10 relative to the casing 50. Rotating the body 10 relative to the casing 50 screws the bolt 20 into or out of the positioning nut 90 thus drawing the casing 50 into or out of the body 10 and adjusting the force of the spring 80 acting on the clutch member 71. Torsion is indicated by the lines and symbols 55 and 19 engraved on the clutch casing 50 and body 10. When the body 10 is rotated to the required torsional position the controlling ring 30 is then rotated to bring the "ON" indicating means 34 adjacent the arrow on the body 10 to force the beads 17 into the guiding flutes 53 and hold them in position to prevent relative rotation of the body 10 and casing 50 (as shown in Figure 2). The force of the spring 80 is such that while the set torsion is not exceeded the clutch members will be held in engagement. Once the torsion is exceeded the teeth on the members 71 will ride over one another. It is to be noted that the pre-decided amount of the torsion may be changed if need be. The socket joint of this invention is also applicable to a non-ratchet type torque wrench handle 200 as shown in Figure 5. While the described embodiments represent the preferred form of the present invention, it is to be understood that modifications will occur to those skilled in this art without departing from the scope of the invention as defined in the appended claims.

Claims: CLAIMS:- 1. A device for coupling a torque li.rsdle to a socket and for limiting the torque applied to the socket by the handle characterised in that the device comprises a body (10) connectible to said handle and having a substantially cylindrical portion (11) at one end thereof; a torque limiting clutch (70) for transmitting torque from the handle to the socket; means (80) coupling the clutch (70) to the body (10) and applying force to the clutch to maintain the clutch in an engaged attitude; a housing (50) for said clutch (70), the housing being telescopically coupled to the body (10) such that rotation of the housing and the body relative to one another displaces the housing and the body towards or away from one another to adjust the force applied to the clutch by said means (80); and control means (30) movable between two positions, in a first of which said housing (50) and said bpdy (10) are freely rotatable relative to one another and in the second of which positions said housing and said body are locked non-rotatable relative to one another. 2. A device as claimed in claim 1 characterised in that the control means comprises a substantially cylindrical controlling ring (30) which coaxially surrounds said cylindrical portion (11); and locking means (17) are located in through holes (16) in the wall of said cylindrical portion (11) and are displaceable inwardly of said portion (11), responsively to rotation of said control moans (30) into said second position, to engaLDe with said clutch housing (50) and ,revent rotation of said clutch housing (50) relative to the body (10). 3. A device as claimed in claim 2 characterised in that said locking means comprises at least one bead (17) whose diameter is greater than the thickness of said wall of said cylindrica portion (11); said beads are engageable in recesses (53) in the outer wall of said clutch housing (50); and said controlling ring (30) has at least one recess (36) on its inner wall for engagement with said beads when said ring is in said first position. 4. A device as claimed in claim 3 wherein said recesses are axially extending. 5. A device as claimed in claim 3 or 4 characterised in that the rim of each said recess (36) within said controlling ring (30) is ramp-like. 6. A device as claimed in claims 3, 4 or 5 characterised in that said clutch housing (50) is engraved on its outer wall with a length of indicating symbols shorter than length of each said recess (53). 7. A device as claimed in claim 6 characterised in that said body (10) is provided on.its outer periphery with a plurality of indic.ating symbols (19) correspoo(hing to said indicatiilg symbols engraved on outer vJ.3ll of s.nid clutch housing (50). 8. A device as claimed in any of claims 2 to 7 characterised in that a ring (40) is secured to the cylindrical. portion (11) and engages in an annular recess (32) in the controlling ring (30); and a pin (32) in one of said recess (32) and ring (40) engages in an arcuate groove (42) in the other of said recess (32) and ring (40) to limit rotation of the controlling ring (30) relative to the body (10). 9. A device as claimed in any of claims 2 to 8 characterised in that said controlling ring (30) is provided with indicating means (34) on its outer wall. 10. A device as claimed in any of claims 1 to 9 characterised in that a first screw-threaded member (20) is secured coaxially within said body (10) and engages in a second screw-threaded member (90) secured to said clutch housing (50). 11. A device as claimed in any of claims 1 to 10 characterised in that said clutch (70) has two clutch members (71) and that the face of one said clutch member is provided with a plurality of protrusions and the face of the other said clutch member is provided with a plurality of corresponding recesses. 12. A device as claimed in any of claims 1 to 11 characterised in that the clutch (70) has two clutch members (71) whose are formed with interengaging tenth. 13. A device as claimed in any of claims 1 to 12 character: in that one clutch member (71) of said clutch is integral with a rectangular plug for engagement with a socket. 14. A device as claimed in any of claims 1 to 13 character: in that said coupling means (80) is a coil spring and engages on locating means on said clutch (70). EMI13.1 CLAIMS: 1. A torque limiting device for a socket wrench comprising a torque limiting clutch (70) for transmitting torque from the socket wrench to a socket, the clutch comprising two frictionally engaged clutch members (71); resilient means (80) applying force to one of the clutch members (71) to maintain such clutch members in engagement with one another, said force being adjustable; and control means (30) movable between a first position wherein said force is fixed and a second position enabling adjustment of said force, characterised in that the torque limiting device comprises a body (10) connectible at one end to said socket wrench; a substantially tubular housing (50) telescopically engaged with the other end of said body (10) opposite said one end and containing said torque limiting clutch (70) for transmitting torque from the socket wrench to a socket, one of the clutch members (71) being adapted (60) for engagement in the socket and the other being coupled to said body (10) by way of said resilient means (80), whereby rotation of said housing (50) relative to said body (10) adjusts said force applied by said means (80); and said control means (30) comprises a sleeve-like member mounted on one of said body (10) and said housing (50) for limited movement relative thereto between said first and second positions, at least one torque transmitting element (17) received in a through hole (16) in said one of said body (10) and said housing (50) said torque transmitting element having a dimension greater than that of the EMI14.1 through-hole so as to project therefrom; and wherein the said other of the body (10) and the housing (50) has a plurality of recesses (53) formed in its radially outer surface for partially receiving said torque transmitting element and said sleeve-like member (30) has at least one recess (36) formed in its radially inner surface for partially receiving said torque transmitting element, ane wherein said torque transmitting element is received in said recess when the control means is in said first position and movement of said control means into said position forces said torque transmitting element from said recess into one of the recesses in said other of the body (10) and the housing (50). 2. A device as claimed in claim I wherein said torque transmitting element is in the form of a bead (17) whose diameter is greater than the thickness of the wall of said one of said body (10) and said housing (50). 3. A device as claimed in claim 1 or 2 wherein said recesses (53,36) are axially extending. 4. A device as claimed in claim 1, 2 or 3 wherein the rim of the said recess (36) within said sleeve-like member (30) is ramp-like. 8 9 ED CLAIMS 5. A device as claimed in any of claims 1 to 4 wherein said other of the housing (50) and the body (10) is engraved on its outer surface with a length of indicating symbols shorter than length of each said recess (53) formed in the said surface. 6. A device as claimed in claim 5 wherein said one of the body (10) and housing (50) is provided on its outer periphery with a plurality of indicating symbols (19) cooperating with said indicating symbols engraved on the outer surface of said other of the body (10) and the housing (50). 7. A device as claimed in any of claims 1 to 6 wherein the sleeve-like member (30) is provided with indicating means (34) on its outer surface. 8. A device as claimed in any of claims 1 to 7 wherein the face cf one 6 said clutch members (71) is provided with a plurality of protrusions and the face of the other of said clutch members (71) is provided with a plurality of corresponding recesses. 9. A device as claimed in any of claims 1 to 8 wherein the opposing faces of the two clutch members (71) are formed with interengaging teeth. 10. A device as claimed in any of claims 1 to 9 wherein one clutch member (71) of said clutch is integral with a rectangular plug for engagement with the socket. EMI16.1 11. A device as claimed in any of claims 1 to 10 wherein s coupling means (80) is a coil spring and engages on locatin means on said other of the clutch members (71). 12.A device as claimed in any of claims 1 to 11 wherein sai one of the body (10) and the housing (50) is the body (10) whose said other end is formed as a substantially cylindric portion (11) which is telescopically engaged with the housi (50) and in which said through hole (16) is formed. 13. A device as claimed in claim 12 wherein a ring (40) is secured to the cylindrical portion (11) and engages in an annular recess (32) in the sleeve-like member (30); and a pin 33 in one of said recess (32) and said ring (40) engag in an arcuate groove (42) in the other other of said recess (32) and ring (40) to limit rotation of the sleeve-like member (30) relative to the body (10). 14. A device as claimed in claim 13 wherein said pin (33) mounted in said recess (32) and engages in the arcuate grod (42) in the ring (40). 15. A device as claimed in any of claims 12 to 14 wherein a first screw-threaded member (20) is secured coaxially within said body (10) and engages in a second screwthreaded member (90) secured to said housing (50).

Inventors: FU-TSAI, LEE
Applicants: FU-TSAI, LEE
Application year: 1979
Main classification: B25B23
IPC codes: B25B23