GB504084A - Improvements in safety wrenches - Google Patents

Abstract

504,084. Wrenches; dynamometers. SUNNEN, J. June 1, 1938, No. 16441. Convention date, Dec. 27, 1937. [Class 61 (iii)] [Also in Group XIX] A wrench with torque-limiting means comprises a hand lever A pivoted at a to a jaw lever B carrying a nut socket 3 and a link 5 connecting the end 4 of the jaw lever B to a tubular member 11 slidable against the pressure of a spring 15 relative to the handle proper 8 fixed on the end of a rod 9 threaded at its forward end to screw into a threaded hole 10 in the forward end 6 of the hand lever. The spring 15 bears at one 'end inside the handle 8 and at the other end against a block 12 fixed by swaging at 13 to the tubular member 11 and apertured at 14 to clear the central rod. The degree of spring pressure corresponding to the limited torque to be applied in tightening a nut is adjusted by turning the rod 9 by its head 18 so that the threaded end 17 advances or retreats in the hreaded hole 10, the pressure thus put on the spring being indicated by a scale 20 on the tubular member 11 and index mark on the handle 8. In operation, the spring supported member 11 permits the handle to move against the jaw lever B when the required torque is reached. In a modification, Fig. 5. the link 5 is replaced by a cam lever 21 pivoted to the end of the jaw lever B and rolling on the inner surface 26 of a slotted lug 27 carried by the tubular member 11; the cam lever is retained in position by a cross pin 29 engaging a slot 28.