GB615789A - Improvements in hoists - Google Patents

Abstract

615,789. Hoists; winding gear. HAMP, A.H Aug. 21, 1946, No. 24915. [Classes 78 (iii) and 78 (v)] A hoist comprises a mast along which a trolley is raised or lowered, a power unit, a winding drum for the hoisting cable of the trolley, a friction wheel or disc associated with the winding drum and adapted for co-operation with a friction pinion on a shaft driven from the power unit, the friction wheel or disc being movable bodily from an inoperative position in which it is clear of the friction pinion and in contact with a brake to hold the winding drum and hence also the trolley stationary, to a fully operative position in which it co-operates with the pinion to wind-up the hoisting cable to draw the trolley up the mast, and also to an intermediate position clear both of the brake and the friction pinion so that the winding drum can rotate freely to allow the trolley to travel down the mast under its own weight, an operating member for moving the friction wheel or disc from the brake position to the driving position, and vice versa, and also for holding the wheel or disc in the intermediate position, and a part which is movable with the operating member and notched or equivalently formed for co-operation with a spring- or weightcontrolled catch or detent to hold the friction wheel in contact with the friction pinion at required times. 'The Figures show the application to a builder's hoist wherein the mast comprising sections 1; 2, 3 is mounted on a carriage 9 and the trolley 53 is raised by a cable 18 passing round pulleys to a winding drum 35, Fig. 3, housed in a casing 22, Fig. 1, on the carriage. The drum is mounted on an eccentric portion 33 of a shaft 32 whereby on turning the shaft by means of a handle 39, Fig. 6, the drum may be moved bodily to bring a friction wheel or disc 36 integral with it, into contact with a driving friction pinion 31 so as to rotate the drum, or into engagement with a brake block 37 to secure the drum against movement, or to an intermediate position to allow free rotation of the drum independent of the drive. The driving pinion 31 is mounted on a shaft 24 driven through chain-and-sprocket gearing 26, 27, 28 from a shaft 25 of a petrol engine 23. When the handle 39 is raised to the dot-anddash line position, Fig. 6, to bring the friction wheel 36 into contact with the pinion 31, a shoulder 46 on a catch lever 42 engages a notch 47 in a cam disc 41 on the boss 40 of the handle to lock the parts in this driving position. When the trolley reaches the desired level, it engages a trip lever which is pivotally mounted on the runway and connected to the catch lever 42 by a cable 60, yoke 59 and rod 58, so as to release the handle which then falls to move the wheel 36 into engagement with the brake block 37. The position of the trip lever can be varied. The supports 57 of the trolley platform 56 may be adjusted lengthwise to vary the angle of the platform. Release of the handle may be effected by hand.