GB586449A - Improvements in driving arrangements for lifts, hoists and the like - Google Patents

Abstract

586,449. Lifts. EXPRESS LIFT CO., Ltd., and DIXIE, W. A. July 6, 1944, No. 12931. [Class 78 (iii)] [Also in Group XXXVII] A driving arrangement for a lift comprises a speed reduction gear adapted to drive the winding sheave of the lift, the input shaft of this gear having connected thereto a multi-vee belt pulley which is driven during normal operation from a main motor by a belt drive, a multi-vee belt pulley mounted on a dead shaft arranged co-axially with the said input shaft and adapted to be driven from an auxiliary motor by a belt drive, and a mechanical clutch arranged so that when it is engaged and no power is being supplied to the main motor, the input shaft can be driven from the auxiliary motor at a low speed by means of the pulley mounted on the dead shaft which transmits power to the input shaft through the clutch. In the embodiment shown in Figs. 1, 3 the driving sheave 17 of the lift is coupled to a worm wheel 16 driven by a worm 16<1> on a shaft 6 provided with a pulley 5 driven through belting by an electric motor. When the lift is to be driven at "levelling speed," this motor is de-energised and a pulley 34, rotated on a shaft 32 by an auxiliary motor 50 through belting 53, is moved axially by a spring 36 acting on a lever 37 engaging a thrust bearing 38 on the pulley 34, and engages frictionally with a brake drum 21 on the pulley 5 to drive the sheave at reduced speed. The spring 36 is normally counteracted by the plunger of a solenoid 45 engaging an arm 46 of a lever having a cam portion 47 co-operating with a screw 48 on the lever 37. The cage may be decelerated or brought to rest by brake shoes 26 on levers 25 engaging the drum 21. Release of the shoes is effected by the plunger of a solenoid 28 which engages arms 29 of levers having cam portions 30 co-operating with screws 31 on the levers 25. The shaft 6 is carried in a double ball thrust bearing 20. When the clutch elements are completely disengaged, electric contacts associated with the solenoid 45 are opened to remove a short circuit from a relay which then operates to permit energisation of the main motor and prevent energisation of the motor 50. The control circuit of the lift includes one timing circuit for measuring a predetermined period of time from the commencement of the deceleration of the lift in preparation for the switching-in of the motor 50 at the end of the said period and a second circuit for measuring a second period of time during which the motor 50 functions to bring the cage to landing level and at the end of which this motor is rendered inoperative. The motor circuits cannot be closed unless all the landing and lift cage doors are locked. Specification 576,528 is referred to.