Patent GB-591701-A (GB)
Title: Improvements in electrical systems of control for lifts
IPC: B66B1/18
Filed: 1945-05-07
Abstract: 591,701. Push-button lifts. EXPRESS LIFT CO., Ltd., HUNT, S. T., and WELCH, J. N. May 7, 1945, No. 11550. [Class 40 (i)] In a semi-automatic lift system the movement of a lift car in the hatchway controls a step-by-step switch so that when a car is within a predetermined distance from the call-originating floor a corresponding "up" or " down " lamp on that floor is illuminated. When other lift cars move into the predetermined distance, before the first car to move therein has commenced to slow down for the floor concerned, their associated step-by-step switches cause the corresponding lamps to illuminate, the illumination of all the lamps being maintained until one of the cars reaches the slow-down position for that floor, whereupon, the lamps associated with the remaining cars are extinguished. The circuits shown are for an 8-floor, 2-car system comprising " up " and " down " landing lamps at each floor, lamps in the cars to indicate whether the next floor of call is above or below, a car slowdown and stopping arrangement, push-buttons at each floor which cause the lift to stop if it is travelling in the desired direction, means for preventing the cars from leaving a floor before a predetermined time, a forward and reverse drive step-by-step selector switch which energizes relays as the car travels up and down the hatchway and electromagnets at the terminating floors for correcting out-of-trim conditions of the selector switch. General operation. The pressing of a button by an attendant causes a car to travel to a desired floor. If an " up " (or "down") button on a landing is pressed, a car which is travelling in the desired direction will stop, during its journey, at that floor. If neither car is travelling in the desired direction, the call is stored and after answering the calls for the opposite direction, the cars reverse to answer the call. As one car slows down at a particular floor, the call from that floor to the other car is cancelled and the other car proceeds to answer the next call if one has been received. Registering position of car. As the car leaves and approaches each floor, it causes an impulse to be given from contacts ZONE, Fig. 6, to the forward or reverse driving magnet DMU, DMD, according to the direction of travel, of a step-by-step switch which controls relays 1S ... 7S and IP ... 9P over cam-operated contacts 1SS ... 7SS and 1PS . . . 9PS as shown in Figs. 3 and 3A. The arrangement is such, apart from variations at the extreme floors, that an S relay is energized when a car approaches each floor and is released when it leaves the next and a P relay is energized when a car leaves each floor and is released when it approaches the next floor but two. Out of trim conditions of the stepping switch are automatically corrected at the terminating floors by relays US, DS. Control from car. On the operation of a floor selecting button, Fig. 1, in the car, the corresponding relay 1C ... 8C is operated, locks up and energizes a common relay CA or CB, Fig. 4, according as the car must travel up or down to reach the desired floor. A corresponding lamp is lit in the car and when the appropriate starting button CSU, CSD, Fig. 4, is operated by the attendant, the up or down relay AU or AD is operated, locks up and starts the motor (not shown). In the absence of calls from the landings, the car proceeds to the selected floor. As it approaches the floor below the selected one, if going up (or above, if going down), the operation of an S relay completes a circuit via a contact of the operated relay 1C ... 8C for relay SL which energizes the stopping relay Z over car-operated contacts SIC. On the operation of the next S relay, when the desired floor is approached, a circuit is made for the releasing winding of the relay 1C ... 8C. Relay SL remains locked up over a time switch TS which is operated while the car is travelling and holds for a time after it stops. Control from landings. Operation of a landing push, Fig. 2, energizes the corresponding "up" or "down" call registering relay 1U ... 9U or 2D ... 8D which locks up and energizes the relay CA or CB of each car, according to its position, to light its "up " or " down " calling lamp. A car travelling in the appropriate direction is stopped by the cooperation of the Sand U or D relays concerned to energize SL. Relay SLA which energizes SL to stop a car travelling in the other direction is controlled over a chain circuit, Fig. 5, in such a way that it can only be operated if the car has no more demands to satisfy in the direction of its travel. SL, in operating, energizes the releasing winding of the call registering relay 1U ... 7U, 2D ... 8D, the circuit being opened as soon as the car begins to decelerate by the relapse of a relay GR, of which only the contact is shown, to prevent the release of an adjacent calling relay when the next S relay operates shortly before the car stops. Control of landing indicators. When a car travelling in the appropriate direction leaves the third floor above or below the calling floor or when any car leaves the third floor above or below the destination floor controlled by a car button, the newly operated P relay in cooperation with the call-registering relay operates the relay 14S and 20S &c., Fig. 7, of the car and floor concerned to light the appropriate landing lamp. This circuit is interrupted when the car approaches the preceding floor and SL operates to slow the car down and releases the register relay U or D but 1US, 1DS, &c. remains locked over contacts of one of the S relays and relay SL until the car motor is switched off. If two cars travelling in the appropriate direction are within three floors of the calling floor, the landing lamps for both will light. The first one to approach the preceding floor without having previously slowed down causes the release of the call registering relay as previously described and, in consequence, the landing lamp of the other car goes out. That of the successful car remains alight until the car stops since the corresponding relay 1US, 1DS, &c. is locked over a contact of SL. Specifications 538,476 ; 563,808 and 574,629, [both in Group XXXVII] are referred to.