GB174988A - Improvements in power hoists - Google Patents

Abstract

174,988. White, A. E., (Independent Pneumatic Tool Co.). Oct. 7, 1920. Drum or barrel winding-machines; driving- gear; overwinding and overrunning, preventing; emergency power cut-off gear; attaching ropes to drums.-A portable power hoist comprises, as shown in Fig. 4, two hoisting-drums 8 rotatably mounted within a casing 3 upon a stationary shaft 5 each driven by a motor-driven worm shaft 21 through gearing at equal speeds and a load cable 16 hangs in a loop between the drums and is secured at each end in a special manner to the outer ends of the drums and separate means are provided for stopping the drums at either end of the wind and for stopping the drums upon loosening of the cable thereon. Teeth 34 on the drums mesh with the teeth of pinions 33 on the shaft of a worm-wheel 23 driven by a worm 22 on the shaft 21. Each end of the cable is passed through an aperture 39 at the end of the drum, Fig. 5, round a spool 43 and doubled on itself between the drum flange 38 and a wedge-piece 40 integral with the drum. The cable is secured by the wedging of the spool in the recess 41. The cable is passed through a sliding finger-piece 149, Fig. 8, and guided into the helical drum groove thereby. A finger 154 engages the drum groove and moves the finger-piece, which at the limits of wind engages stops 156 on a bar 136 connected by levers with the engine valves so that the engine is stopped when the bar 136 is moved. One wheel in the driving gear, preferably the worm-wheel 23, comprises as shown in Fig. 17 a driven rim part 241 connected by spring- pressed pawls 311 with a hub part 231 driving the drums through gearing. Clockwise rotation raises the load. When lowering, if the weight of the load is removed the hoisting-cables loosen and contact with the drum casing. The friction stops the rotation of the drums and the hub 231, the pawls being automatically disengaged from the hub.