Patent GB-545755-A (GB)
Title: Improvements in electrical systems of control for lifts
IPC: B66B1/18
Filed: 1941-06-13
Abstract: 545,755. Lift control systems. EXPRESS LIFT CO., Ltd., and HUNT, S. T. June 13, 1941, No. 7472. [Class 40 (i)] In a collector-type system like that described in Specification 538,476 which operates as if the cars were running in the same direction around an endless track, up calls being stored on one side of the track and down calls on the other side and each car in general answering all calls stored in a zone between itself and the next car ahead, in order to contribute to the desirable condition that the cars should be evenly spaced around the track, the unanswered calls are timed and classified as short, medium and long term, and a car is able to refuse short term calls or both short and medium term calls under certain conditions which depend on the distance of the car behind the next car ahead and on the total number of unanswered calls stored in the zone. General arrangement.-A 3-car system for 10 floors is described, with up and down call relays 2U .. 10U, ID ..9D, Fig. 1B, controlled by the landing buttons-and car call relays 1C .. 100, Fig. 1A, for each lift controlled by the car buttons. Relays IF .. 10F, Fig. 2A, are controlled by contacts that are actuated by the car as it travels between the floors, and in turn control floor relays 1G ... 10G in accordance with a key shown in Fig. 2B. Each lift has up and down zone relays 1H . . 10H, 1K .. 10K which are interconnected with those of the other lifts so that the operating zone of the lift at any time is indicated by the relays energized, the endless track being apportioned between the three lifts, provided all are in service. These relays are controlled by the F relays and by relay UD which is dependent on whether the car is going up or down. If a car reverses at an intermediate floor, its position on the endless track is altered and the change-over of UD - energizes a fresh set of zone relays. Relay UD, Fig. 3, is controlled by self-locking relays AU, AD which also control the up and down contactors and which are operative alternatively under the influence of the landing call and car call relays. A lamp is lighted at the lowest floor to indicate the next lift to leave, and a lift having that floor in its zone proceeds thereto after answering all its calls, provided no other lift is already there. If a lift fails to start, or stops improperly, its calls are transferred to the succeeding lift. Timing unanswered calls, and refusal of calls.-In each lift, each energized, zone relay reduces the resistance in the circuit of two marginally adjusted relays ST, MT, Fig. 4A, so that their condition indicates within limits the distance of the car from the next car ahead. Relays HQ, FQ, EQ are similarly controlled jointly by the zone relays and call relays to indicate within limits the number of unanswered calls in the zone of the lift. These two sets of relays affect relays SQ, MQ, which are brought into use by TX where more than one lift is in service, the control being varied by TY when all the lifts are in service. The calls at the intermediate landings are timed by means of rotary switches D2 .. 9, U2 .. 9, Figs. 5A, B, which have one controlling wiper for each lift and are stepped by impulses produced by the periodic discharge of a condenser. The resistance in the charging circuit is increased when only two lifts are in service or when any MQ is up to increase the impulsing period and hence the range of short and medium term calls. Relay, SL, which initiates slowing down to stop the car at the next floor, is controlled for car calls by the G and-C relays. For landing calls, it is controlled by the G, D and U relays and the controlling wiper of the appropriate timing switch, which puts the circuit under the influence of SQ and MQ for short term calls and MQ only for medium term calls. In addition, it is provided with chain circuits which permit a car to answer a call for the opposite direction of travel, provided it is the first call ahead on the endless track. Control by attendant. When the starting of a lift is under the control of an attendant, a lamp is provided to indicate the existence of landing calls in its operating zone. The actuation of a "pass push" prevents unnecessary stopping when the car is fully loaded, the circuit of SL for landing calls being opened by relay PP.