GB687129A - Power operated rotary impact tool - Google Patents

Abstract

687,129. Screwing-up nuts. DISSER, M. E. Nov. 2, 1951, No. 25733/51. Class 83 (iii). A power-operated rotary impact wrench comprises means for imparting a succession of impulses to a driving member 23, a driven member 42, and means 50 for connecting the members and for cancelling-out the effect of the impulses when the load on the driven member exceeds a predetermined value. An electric driving motor 12 is associated with a rotatable pole-changing device 18 for reversing. The motor is connected to the anvil 23 via gearing 13, 28, 29, a planet frame 27, a non-rotatable sliding sleeve 32 and interengaging lugs 33, 24. The anvil is rotated continuously until its rotation is opposed, when the sleeve 32 is intermittently forced back against a spring 34 so as to deliver a series of impacts. The anvil 23 is connected to the tool-holding member 42 by a sleeve 35, which is attached to the anvil by a polygonal projection carrying a retaining ball 39, a member 40 fast with the sleeve 35, and a torsion spring 50. The torsion of the spring 50 is adjusted and maintained by screws 49 engaged in a plurality of holes 47. The heads of the screws project into slots 48 in the sleeve 35. Thus, when the torque exerted on the work exceeds the torsion of the spring, the screws 49 slide in the slots 48 and absorb the impact forces. The device 35 may be used on any type of rotary impact tool. In a modification, the slots 48<SP>1</SP>, Fig. 5, are inclined so as to withdraw a toothed member 56 out of contact with a similar member 57 when the maximum torque is exceeded. A removable head 44, on either tool, is retained by a spring-pressed ball and is shaped according to the nut or bolt to be rotated.