GB786227A - Improvements in or relating to ratchet wrenches - Google Patents

Abstract

786,227. Screwing-up and unscrewing nuts and bolts. ARO EQUIPMENT CORPORATION. Aug. 15, 1955, No. 23479/55. Class 83(3). A power-operated ratchet-wrench comprises a C-shaped head with jaws to receive the small diameter of the nut, inwardly of which a partial cylindrical surface is provided of a size to receive the corners of the nut, roller-means for engaging the corners, spring-means biasing the roller-means so that when the head is rotated in one direction the nut is engaged and when reversed the roller-means move over the nut, and power-operated means for oscillating the head in a supporting-frame. A pneumaticmotor 10, Fig. 1, controlled by a valve 12, forms a handle for the wrench and is secured to a frame 18 which is flat at its forward-end, Fig. 3. The motor-spindle 16, Fig. 1, drives a cam 38 which reciprocates a spring-returned rack 26. The rack engages a pinion 24 which in turn oscillates, through gear-teeth 36, a C-shaped head 28. The latter is carried in an arcuate guideway of the frame and is adapted to fit over the small diameter of a hexagon nut or bolt. A pair of spring-biased rollers 60, 62, Fig. 4, engage the corners of the nut and rotate it through 30 degrees at each clockwise oscillation of the head. A spring-controlled latch 78 prevents the nut from turning back when the head reverses. An alternative form of ratchet-grip comprises four rotatable dogs 160, 160a, 161, 161a, Fig. 10, which grip in pairs, and a serratedmember 169 which engages the nut-corners to prevent undesired reverse rotation.