GB733196A - Improvements in or connected with loading platforms - Google Patents

Abstract

733,196. Guided platform hoists ; lifts. COLDMAN, J. W. Nov. 3,1953 [Nov. 3, 1952], No. 27581/52. Class 78 (3). A guided platform hoist for attachment to the outside of a building having, at each floor level, a door or gate closed opening in the outer wall, is provided with means (not shown) which, when the platform 4 is approximately aligned with a floor, automatically unlocks the associated gate or door and so allows access to a lever 7 on the platform which, when actuated, moves a pair of bolts 14, 15 into engagement with slots 16 in the guides 1, 2 and, simultaneously, breaks the circuit of the push-button landing switches which control a motor-driven hoisting winch (not shown). Outward movement of the bolt 14 allows a pair of spring-loaded roller carrying members 21, 22 to slide outwardly so removing cam surfaces thereon (not shown) from the operating members of switches 23, 24 which then complete the circuits for manually operated " up " and " down" inching switches (not shown) on the platform. Cams (not shown) mounted on guide 1, depress the members 21, 22 so cutting out the inching circuits alternately, through switches 23, 24, as the platform is inched up and down. When the platform has been accurately levelled with the floor, the bolts rest in the bottoms of slots 16. Reverse movement of lever 7 retracts the bolts 14, 15 and closes the landing call button circuit; and when the platform moves away from the landing, a roller 12 disengages from a cam 13 and allows a catch 8 to lock the lever 7 in its boltretracted position.