GB839554A - Improvements relating to overload clutches - Google Patents

Abstract

839,554. Overload-release clutches. SCHRO TER, K., and WALTERSCHEID-MULLER, B. Aug. 28, 1956 [March 27, 1956], No. 26325/56. Class 80 (2). A clutch which, on overload, is automatically disengaged and remains so until the speed of the input member 1 is reduced to within a predetermined difference from that of the output member 13, comprises an intermediate sleeve 9 having axially slidable thereon, by pin-and-slot connection 17, a member 7 having a pair of facial projections pressed against a stepped cam face 5, Fig. 3, on a member 2, fast to the input member 1, by one end of one or more springs 8 the other end of which abuts on a flange of the intermediate sleeve 9 to cause holes 16 in the flange to engage clutch pins 15 on the output member 13. When, on overload, the member 7 rides over the crest 11 and down the cam face 6 of the input member 2, the spring 8 expands and becomes sufficiently free of stress to permit a light spring 12 to thrust the intermediate sleeve 9 to the left (position shown), disengaging it from the output clutch pins 15. This declutched condition persists until the speed of the input member 1 is reduced to sufficiently near that of the output 13 to permit radially spring-pressed keys 21, Fig. 6, on the output member 13 to enter grooves 26 in the intermediate sleeve 9, whereupon the latter is turned to cause the member 7 to ride up the cam steps 4, 5 of the input member 2, re-stresssing the spring 8 which re-engages the intermediate'member 9 with the output clutch pins 15. The grooves 26 taper to a cylindrical surface to depress the Keys 21 to an inoperative position which the clutch is engaged, and their leading edges are set back radially to reject engagement of the keys 21 until the predetermined speed difference is reached. For a similar purpose the keys 21 have slight tangential freedom in opposition to springs 23.