Patent GB-642685-A (GB)
Title: Improvements in or relating to control systems for electric elevators
IPC: B66B1/18
Filed: 1947-10-07
Abstract: 642,685. Push-button-controlled lift systems. WESTINGHOUSE ELECTRIC INTERNATIONAL CO. Oct. 7, 1947, No. 26929. Convention date, Oct. 7, 1946. [Class 40 (i)] In a lift system having a plurality of cars serving a plurality of floors in response to up and down calls, an upward moving car normally answers all up calls and automatically reverses at the highest down call when no service is demanded above this, and thereafter answers all down calls. A full down car is switchable to byepass down calls from lower floors, and the next unloaded up car is then reversed at the highest down call below the floor at which the byepass switch was operated to answer the byepassed down calls from lower floors. Alternatively the up car reversal may await the registration of a predetermined quota of down calls from lower floors within a preselected service demand zone. The invention is described with reference to an installation having two cars serving seven floors of which the second, third, fourth and fifth fall within the service demand zone. Movement of the lift is initiated by an attendant's switch and destination floors are selected by push-buttons within the cars which may over-ride floor calls or service demand calls. The service demand zone may embrace any desired floors, and may be applied to up calls. Operation at rest.-hen both cars are at the lower terminal and no calls are registered, the up preference relays W of car A and BW of car B (Fig. 3) are operated through a circuit including the normally closed top limit switches 28T and B28T, and the switch 58 (Fig. 5) is open to enable the quota relay Q to reverse an up car in response to a predetermined number of down calls from the service demand zone. Response to the highest down call.-Operation of,' e.g., the fourth and sixth floor down call buttons 4D, 6D (Fig. 4), causes holding relay 4DR to operate to disable the high call relays K, BK, to close contacts 4DR3 in the circuit of the quota relay Q (Fig. 5) and to energize segments g4, Bg4 of a floor selector switch (Fig. 2, not shown), whose brush carriage is traversed by the lift motor, to stop the next down car. Relay 6DR is operated to function similarly, but does not affect the circuit of relay Q. Closure of car switch CS (Fig. 3) by the attendant operates the up switch U and the running relay M through the upper stopping limit switch STU and the usual safety devices 23. Relay M prepares the control circuits of car A for operation, and switch U releases the magnetic brake 15 on the winding shaft, energizes through resistance R1 the field winding GF of the generator GA supplying power to the winding motor 14, and operates the high-speed relay V to short-out the resistance R1 and excite the motor to run at its normal high speed. The destination floor of the car is determined by the floor down calls 2D-7D or up calls 1U-6U (2U, 3U, 6U only shown), or by control buttons 2c, 3c, 4c, 5c, 6c, 7c (Fig. 4) mounted in the car for operation by the attendant in the usual manner, which operate to over-ride the demands of floor calls or service demand calls and are held operated by coils 2cc &c. until the direction is reversed. The car moves upwards in response to fourth and sixth floor calls, and on approaching the sixth floor brush 34 engages the floor selector switch segment d6 to operate the high call relay K which operates the high call reverse relay J (Fig. 5) to energize the slow down inductor relay E, and holding relay G (Fig. 3). As relay E comes opposite an associated magnetic plate in the sixth floor hatchway, its magnetic circuit is completed and it operates to release the high speed relay V, which reconnects the resistance R1 in the generator field to slow down the car, and energizes the stopping inductor relay F. The latter operates when it comes opposite its associated magnetic plate in the hatchway, to release the running relay M and the up switch U which brakes and stops the car at the sixth floor. The operation of relay J and release of relay M together release relay W, which operates the down preference relay X through its back contacts W2 and the normally closed bottom limit switch 28B to prepare the circuit of the down switch D (Fig. 3), and energize coil 6DRN (Fig. 4) through brush 40 and floor selector switch segment f6 to de-energize relay 6DR to cancel the sixth floor down call. After taking on the calling passengers, car switch CS is closed by the attendant to operate the down switch D and relay M through a circuit including the contacts X1, the lower stop limit switch STD, and the safety devices 23, to prepare the control circuits, release the brake, and energize the winding motor to lower the car first at low and then at higher speed after operation of the high speed relay V to short-out the resistance R1. Response to down special service demand.-As the car approaches the fourth floor, brush 41 engages segment g4 of the floor selector switch to operate the stopping relay S, which energizes the slow inductor relay E and its holding relay G. As relay E comes opposite an associated magnetic plate, it operates to release the high speed relay V, which reconnects the resistance R1 in the generator field to slow down the car, and energizes the stopping inductor relay F. As the latter comes opposite its magnetic plate, it operates to release the running relay M and down switch D, which release the brake, stop the motor, and energize the coil 4DRN through brush 40 and floor selector switch segment f4 to de-energize relay 4DR to cancel the fourth floor down call, break the quota relay circuit at 4DR3 (Fig. 5) and close 4DR4 to remove its effect on the service demand relays. If the car is fully loaded at the fourth floor, the attendant byepasses down calls from lower floors by opening contacts 27a (Fig. 4) to disable the stopping relay S from operation, opening contacts 27b (Fig. 5) to disable operation of the high call reverse relay J while car A is travelling up or down, and closing contacts 27c (Fig. 5) to operate the service demand relay 4Y (Fig. 5) through brush 43 and segment i4 of the floor selector switch, which closes contacts 4Y1 and opens contacts 4Y2 to prepare for reversing the next unloaded up car at the highest down call below the operation of the byepass switch when an unanswered quota exists, and relay 4Y holds over contacts 4Y3 until this reversal energizes the cancelling coil 4YN. Closure of car switch CS operates the down switch D and the running relay M and the car moves downwards as before. Down calls from second, third and sixth floors are assumed to be received. Button 6D registers a down call as before, while buttons 3D, 2D operate holding direction relays 3DR, 2DR (Fig. 4) to energize segments g3, Bg3 and g2, Bg2 of the floor selector switch to stop the next down car, either A or B; to disable the operation of high call relays K, BK; and to connect resistors R2, R3 in the circuit of the quota relay Q. Sufficient current passes to operate Q, closing contacts Q1. As car A descends, car B is assumed to ascend on closure of switch BCS which operates up switch BU and relay BM as before, and as car B approaches the third floor, brush B34 engages segment Bd3 of the floor segment switch to operate the high call relay BK which operates the high call reverse relay BJ to hold, and to energize the slow down inductor relay BE and its holding relay BG. As relay BE comes opposite its third floor magnetic plate, it operates to release high speed relay BV, which inserts resistance BR1 in the field of generator BGA to slow the car, and energizes the stopping relay BF. As the latter comes opposite its third floor magnetic plate it operates, to release the up switch BU and the running relay BM, which stop the motor and apply the brake as before. Since contacts BJ2 are open, relay BM also releases the up preference relay BW to operate down preference relay BX. Thus relays BM, BX are reversed so that on starting car B will descend. When relay BJ was operated to reverse the car, it also energized the neutralizing coil 4YN through brush B35 and floor switch segment Be3 to cancel the service demand set up by energizing coil 4Y, and restore the demand circuit to normal. After taking passengers at the third floor, car B descends on operation of switch BCS, responds to the second floor down call, and proceeds to the lower terminal. Down byepass operation without quota.-If switch 58 (Fig. 5) is closed to short-out contacts Q1 of the quota relay when car B is at the lower terminal and car A is at the upper terminal, and if down calls are registered from the sixth and fourth floors by buttons 6D, 4D, so that car A descends to the sixth floor where it is fully loaded and the byepass switch is operated, contacts 27a (Fig. 4) open to disable the stopping relay S, and contacts 27b (Fig. 5) open to disable the high call reversing relay J, while contacts 27c close to operate the holding service demand relay 6Y through brush 43 and floor switch segment i6 to close contacts 6Y1 and open contacts 6Y2 to prepare for reversal of next unloaded up car at the highest down call below the sixth floor. On stopping at the sixth floor, the brush 40 of car A engages the floor switch segment f 6 to energize the restoring coil 6DRN to cancel the sixth floor down call by de-energizing relay 6DR, which recloses contacts 6DR2 and 6DR3. On closure of switch CS, down switch D and running relay M are operated as before, and the car descends, byepassing the fourth floor down call. If a down call is now made from the seventh floor, button 7D operates the holding direction relay 7DR, which disables the high call relays K, BK. If car B now ascends on closure of switch BCS, and approaches the fourth floor, the brush B34 engages the floor switch segment Bd3 to operate the high call relay BK, which in turn operates the high call reverse relay BJ. This holds and energizes the slow down relay BE and its holding relay BG, a