Patent GB-545814-A (GB)
Title: Improvements in or relating to mechanical power transmission apparatus for lift systems
IPC: B66B11/04
Filed: 1941-02-11
Abstract: 545,814. Lift systems. EXPRESS LIFT CO., Ltd., and DIXIE, W. A. Feb. 11, 1941, No. 17565/40. [Class 78 (iii)] In a lift system an electric motor drives through a fluid coupling an epicyclic gearing, capable of being engaged under load, which drives the hoisting sheave. The torque for driving the lift is by connection to the runner of the and not by direct mechanical connection to the impeller. A motor 1, Fig. 2, drives the impeller 4 of the fluid coupling, the runner 5 of which is fast to the shaft 6 keyed to a multivee belt pulley 7 which drives a pulley 8, Fig. 3, housing planetary gears 10, 11, formed in one, running on a spindle 12 fast in the pulley 8 and of which 10 meshes with a sun wheel 13 keyed on a shaft 15, and 11 meshes with a sun wheel 14 in one with a brake drum 17, the shoes 18, 19 of which are held on by springs and released by solenoids. The closing face 8a of the pulley 8 acts as half of a friction clutch 20 which serves as direct drive clutch for the shaft 15 which drives worm reduction gearing 24 which drives the hoisting sheave of the lift, the clutch 20 being engaged by a spring and disengaged by a solenoid, the build up times of the solenoids for the brake 17 and clutch 20 being so relatively, adjusted that the clutch is not completely disengaged before the drive is beginning to be taken up by the epicyclic gearing in the pulley 8. The change over to levelling speed may be controlled by a slowing plate in the lift shaft, and the stopping by a stop plate which cuts off current to the motor and to the solenoids, In a modification the worm reduction gear 24 is dispensed with and the shaft 6 driven by the fluid coupling runner is keyed to the housing 26 of Fig. 4, the epicyclic gearing which now has three planet wheels formed in one and three sun wheels, one of which, 31, is keyed to the shaft 34 that drives the multi-vee pulley 35 that drives a large pulley driving the hoisting sheave. A second sun wheel 32 is on the sleeve hub of a brake drum 38, and a third on the sleeve hub of a brake drum 41. The brake, shoes for both drums are applied by springs and released by solenoids, and are interlocked so that both cannot be released simultaneously. The gears are such that with drum 41 held the lift is driven at normal speed, with drum 38 held the speed is reduced for levelling. Both drum brakes applied together acts as a main brake, but it is also desirable to provide a main brake on the hoisting sheave. In this modification hand-winding gear must be arranged to operate between the fluid coupling and the reduction gearing. With the two arrangements above described reversal of the lift motion is obtained by reversing the motor, involving the provision of the necessary electrical control gear. This can be avoided in another modification by introducing bevel reversing gearing 47, on Fig. 6, on the output shaft 34 of the epicyclic gearing which drives the pulley through a dog clutch 52. This is shown with a fluid coupling of the adjustable scoop type, the scoop 43 being controlled by a lever 44 enabling the power transmitted to be controlled. In a further modification, not shown, two sets of epicyclic gearing with three sun wheels and two brake drums each are employed in series between the fluid coupling and the belt pulley to enable "corrective levelling" to be carried out. When this arrangement is used for heavy goods lifts where levelling is done with doors open, the doors and the brake-operating coils can be interlocked to avoid more than levelling speed when the doors are open and means in the lift shaft can be arranged to prevent travel while doors are open more than a pre-determined small distance from floor level. In a further modification, the motor may drive through bevel gearing 79; 80, 81, Fig. 9, two opposite fluid couplings of the scoop type on a shaft 86 which drives, through epicyclic gear 87. with a pair of brake-controlled sun wheels, a pulley belt geared to the sheave driving pulley. A small D.C. generator 88 is also driven by the motor to supply the control solenoid circuit.