Patent GB-643302-A (GB)
Title: Motor operable elevator structure
IPC: B62B3/06
Filed: 1948-06-07
Abstract: 643,302. Load-handling device. TODD, E. K., and AERL, Inc. June 7, 1948, No. 15299. [Class 78 (iii)] An elevator structure comprises in combination a pair of substantially upright spaced members connected together at least near the top and bottom and disposed in parallel relation, a screw member disposed centrally therebetween and substantially coextensive with the major portion of the length thereof, a movable platform, a nut mounted for rotation only upon the platform and threadable on the screw member, a reversible electric motor supported by the platform and movable therewith, a power connection between the motor and the nut for reversibly rotating the latter for platform elevation and control, the motor being disposed to one side of the upright portions and screw member and the platform being extended oppositely therefrom for load accommodation. An H- or I-section column 10 is secured between upper and lower levels and a screw 11 extends parallel to the column. A platform 14 having sets of rollers 18 engaging the flanges of the column has a nut engaging the screw and is driven by V-belts 28 by a motor M. The motor M is hingedly mounted on a frame 34 on the platform 14 and the motor has a grooved shaft 37 for the V-belts. Motor control limit switches 41, 42 are provided for stopping the motor. In the mobile structure shown in Fig. 4, the platform support 124 extends from two interconnected sleeves 122 slidable on parallel shafts 115 connected by members 116 and 119 A central screw 118 is mounted on the base 110 parallel with the upright members 115. A motor 126 is mounted on the platform and has a pinion rigidly secured to the shaft and meshing with the toothed exterior of the nut engaging the screw 118 for moving the platform with speed reduction. The pinions are antifrictionally mounted in a housing. The platform support has contacts 150, 151 on its upper and lower surfaces which co-operate with limit switches 120 and 121 on the base and upper cross-members, respectively. A member 152 connects and insulates contacts 150 and 151. At either end are two pairs of contacts, 153a, 153b and 154a, 154b at one end, 155a, 155b and 156a, 156b at the other end, which are selectively bridged by the contacts 150, 151 which may be in the up (U), neutral (N) or down (D) position. There is a switch S in the motor M, 126, circuitconnected to the mains plug P which is in series with the motor field coil 126f. With the connections as shown in Fig. 7 there is movement of the platform upwards. Two further pushbuttons UPB and DPB are provided in series with solenoids SU and SD and having stick switches BUS and BDS carried by the member 152 which carries the cores CU and CD when the up switch 121 is operated by contacting insulator 151a, the motor field coil circuit is broken, the solenoid is moved to the neutral N position and is de-energized and movement ceases. If load lowering is desired the down push-button D.P.B. is closed, energizing the solenoid SD and withdrawing the core CD, thus pulling the member 152 downwards so that the contact 150 bridges the down contacts 156a, 156b and closes the motor field coil circuit and the platform moves downwards. The stick switch BDS closes a bridging circuit across the push-button DPB so that the solenoid remains energized even though the push-button is released.