GB931301A - - Google Patents

Abstract

931,301. Lift control systems. EXPRESS LIFT CO. Ltd. Jan. 9, 1962 [Jan. 26, 1961], No. 3090/61. Drawings to Specification. Class 78 (3). In a multi-car lift system, the landing call buttons and associated relays are divided into groups or zones and means are provided for comparing the time intervals for which the groups have had calls registered within them and for despatching an available car from the floor at which it becomes available to answer first a call in the group having a predetermined time interval relative to the time intervals of the other groups. In the described embodiment, closure of a landing call button energizes the corresponding zone relay which causes further relays to be operated after time intervals of ten, fifteen, twenty ... sixty seconds. When a car becomes available, a relay is operated to energize a zone relay for the zone with the longest time interval causing the car to be despatched to that zone. If no zone has a ten-second time interval, the car is sent to a zone with outstanding calls in a predetermined priority order. If more than one car is available, the car nearest the lowest up-call or highest down-call in the selected zone is despatched. If it is required that one zone should have priority over the other zones, it is arranged that the time interval relays are operated after shorter time intervals of, for example, eight, twelve, sixteen seconds instead of ten, fifteen, twenty seconds. The system may be arranged so that a car, when allocated to a zone, answers calls within that zone and then continues to answer all calls ahead of it.