Improvements in Apparatus and Appliances for Preventing the Overwinding and Underwinding of Cranes, Hoists, Lifts, Winding Drums, and the like.

摘要

104,591. Allen & Co., E., and Furnival, E. H. May 24, 1916. Stopping automatically at end of run; indicating limit of wind.-In electrically-operated cranes, hoists, lifts, winding-drums, &c. the current is cut off automatically when the load approaches the limiting positions by means actuated by a traversing-nut c on a screwed shaft b geared or otherwise connected to the winding-drum. On the underside of the nut c are pivoted two blocks d, d' which are in alinement with adjustable screwed stops h, h1 mounted in a double-armed frame f provided at its centre with a peg i. The frame f can be moved along a shaft e in either direction against the action of springs, and in its central position, the peg i engages a similarly-shaped peg j carried by a vertical rod k. A coiled spring l forces the rod k upwards as soon as the peg i has been moved off the peg by the movement of the frame f caused by either of the blocks d, d1 bearing against the corresponding stop h, h1. The upward movement of the rod k actuates an electric switch (not shown) which cuts off the current from the hoisting-motor. The nut c carries two insulated buttons h, h1, one of which closes one of the pa.irs of contacts o, o or o1, o1 just before the current is cut off, and actuates an audible or visual signal.