Patent GB-605509-A (GB)
Title: Long-shaft stud driver
IPC: B25B23/10
Filed: 1945-12-27
Abstract: 605,509. Studding-chucks. AIRCRAFT SCREW PRODUCTS CO., Inc. Dec. 27,1945, No. 34969. Convention date, Jan. 25. [Class 83 (iii)] A driver for long-shafted studs has jaws which grip the stud close to the work-engaging thread while the axial forces to tighten the jaws act on the end of the nut-engaging portion of the stud bearing against an abutment of the tool; the driver is also provided with means to hold the jaws expanded for passage through them of the stud shaft, means to close the jaws to a position in which a predetermined portion of the stud shaft is engaged by the jaws, and with means to tighten the grip when such engagement has occurred. A driving shank 1, Fig. 1, has a cross-bore 3 in which a pin 8 is secured and a cylindrical cavity 4, the side wall of which is provided with two L-shaped slots 5, Fig. 2A. The ends of the pin 8 project into slots 7, Fig. 3, cut in an outer cylindrical shell 6, the lower end of which is flared to co-operate with inclined faces of threaded jaws 16 opened by springs 28 and hinged on pivot pins 27 in recesses 25 in an inner cylindrical shell 17 having an axial bore 24 to accommodate the stud. Rotation between the inner and outer shells is prevented by a key 20 secured to the inner shell and engaging a slot 22 in the outer shell. The upper end of the inner shell is threaded at 29 to engage a driving screw 30 which fits the cavity 4, has an axial bore 33, and carries pins 32 engaging the slots 5. A compression spring 34 is interposed between a hard rubber cushion 34<SP>1</SP> and a collar on a pin 37 axially movable within the bore 33 and supported on a shoulder 23 of the inner shell. A lower extension 38 of the pin 37 is of a length selected according to the dimensions of the stud. A torsion spring 11 anchored between the shank head and the inner shell offers resistance to rotation of the shank relatively to the shells in the direction of the stud thread. The jaws may have a knurled surface to engage the stud shaft when no continuation 44 of the work-engaging thread 43 is provided. In operation, a stud, screwed by hand into the first one or two threads of a hole, is entered into the bore 24 to engage the pin 37, lifting the inner shell in relation to the outer shell until the pins 32 reach the upper ends of the slots 5, at which point the jaws begin to engage the portion 44 of the work-engaging thread of the stud. The shank is now rotated, entering the pins 32 in the arm 5<SP>1</SP> of the slot 5 and rotating the screw 30 and inner shell to screw the jaws on to the stud and raise the pin 37 until it bears against the rubber cushion 34<SP>1</SP>. The increased torque now required to turn the shank results in the shank turning against the restraint of the spring 11 as far as the slots 7 will permit, whereupon the outer shell 6 is again rotated and the threaded connection between the screw 30 and the inner shell causes the latter to ascend tightening the grip of the jaws to screw the stud home. The tool is detached from the stud by reverse rotation of the shank. In a modification, a shank 101 has a head 102 fitting a cavity 103 of a cupshaped member 104 provided with a tapped hole 106 engaging a threaded extension 107 of the head. A pin 108 is secured to the head with its ends projecting into slots 109 wider than the pin, but otherwise similar to the slots 7 of Fig. 3. A torsion spring 110 is anchored between the shank head and the member 104 connected by screws 113 to a shell 114 having an internally flared lower end to co-operate with the inclined faces of jaws 120 forming an integral part of the inner shell which has an upper part 119 threaded at 121. The portion 119 is provided with a shoulder 122 and may be integral with the shell 118 or connected thereto by dogs to render it interchangeable with similar parts having a different size of thread 121. A pin 127 with a flange 128 is inserted into the upper portion of part 119 so as to be axially movable therein. In operation, the tool is lowered over a stud until the nutengaging thread of the latter is just below the thread 121. The tool is then screwed on to the stud until the pin 127 is pushed upward against the extension 107 and the shell 118 is lowered in relation to the outer shell to close jaws 120 around the stud causing sufficient resistance to arrest rotation of the shells so that the shank rotates in relation to member 104 against the spring 110. Owing to the engagement of the shank head with the thread 106, member 104 and with it the outer shell 114 is raised relatively to the shank and the inner shell, tightening the grip of the jaws to drive the stud home. Specification 564,529 is referred to.