GB629561A - Improvements in driving gear for lifts - Google Patents

Abstract

629,561. Cage lifts. BRITISH THOMSONHOUSTON CO., Ltd., and OLDHAM, T. J. F. April 28, 1947, No. 11310. [Class 78 (iii)] In a gearless lift driving mechanism independent manually operable means are provided for moving the cage under emergency conditions which prevent the lift from slipping due to unbalance between the lift weight and the counterweight during the movement. A worm wheel 11, Fig. 1, is keyed to the shaft on which the driving sheave 1 is mounted, and a worm 8 mounted in bearings 9, 10 is engaged with it. A manually operated lever may be applied to square end 12 of the worm shaft. The worm gearing may be irreversible to prevent slip or alternatively ratchet means may be provided. The worm and worm wheel may be associated with idler 2 instead of sheave 1. In operation the brake on the driving sheave is set while the worm is engaged and then released. In a second embodiment wherein the brake on the driving sheave remains set, the ends of the hoisting rope 5 instead of being connected to separate anchorages 6, 7 are passed over idler pulleys so that the ends are brought together and connected to a joint block 16, Fig. 3, normally secured to a fixed beam 17 by a screw 17<SP>1</SP>. For moving the cage a tommy bar is inserted through suitable apertures 18 in the block to engage recesses 20 in the beam and screw 171 is temporarily released as the block is jacked along the beam. Apertures 18 are preferably of different size and/or spacing from recesses 20 to enable small movements to be readily effected.