GB431624A - Improvements in or relating to power-operated wrenches - Google Patents

Abstract

431,624. Yielding shaft-couplings ; slipping-clutches. MOSS, E. W., 75, Victoria Street, London.-(Ingersoll-Rand Co. ; 15, Exchange Place, Jersey City, New Jersey, U.S.A.) Dec. 28, 1934, No. 37157. [Class 80 (ii)] [See also Group XXII] In a portable device for screwing-up and unscrewing nuts and screws the tool is driven through a resilient rubber torsion spring and a slipping-clutch so that the energy of the driving motor may be stored in the spring to deliver torsional blows to the tool. The casing of a reversible electric or pneumatic motor has attached thereto a casing 16 containing a reduction gear and provided with radial handles. A sleeve 12 is secured to the casing 16 and carries a bearing 23 for the tool socket 13. Bevelled clutch teeth 26 on the socket engage similar teeth 27 on the end wall 31 of a tubular hammer 21 which is rotated from the motor shaft 20 through a clutch 37 and rubber spring 22. The end portions of the spring are moulded within metal caps 59 having radial teeth 61 engaging recesses in the hammer wall 31 and in a ring 36 pinned to a central spindle 29 which is freely slidable and rotatable within the wall 31 and the socket 13. A further ring 31a has teeth 33 engaging recesses in the rear end of the hammer 21 and is secured thereto by a spring ring 34 so as to support this end of the hammer slidably upon the ring 36. Clutch teeth 39 on the ring 36 are normally held out of engagement with teeth 38 on the shaft 20 by means of a spring 42a located in a recess in the spindle 29 and pressing a plunger 42 against the end of a recess in the shaft, a pin 44 in the spindle engaging a slot 45 in the plunger to limit their relative movements. In operation the machine, with a wrench 48 in the socket 13 and the clutches 25, 37 closed and open respectively, is applied to the work. Axial pressure on the wrench closes the clutch 37, whereupon the wrench is driven to tighten a nut. When the resistance of the nut to turning increases the rubber spring 22 is placed under additional torsion whereby it twists and shortens in length and allows the clutch teeth 26, 27 to slip. As soon as the teeth have passed each other the spring unwinds and the hammer 21 delivers a torsional blow to the wrench, these blows being repeated rapidly to set the nut and being increased in force by the momentum of the hammer and the torsional energy of the spring. When axial pressure on the machine is released the spring 42a opens the clutch 37 and the wrench ceases to rotate. To increase the resilience of the rubber spring 22 it is provided with a number of longitudinal ribs 64, Figs. 3 and 5, joined at their inner ends by a thin cylindrical wall 65, Fig. 2, in which are embedded a number of metallic rings 58 which prevent the spring from binding on the spindle 29 during torsion. The end caps 59 are copper-plated and are treated in a known manner to secure adherence to the rubber.