Patent GB-460805-A (GB)
Title: Improvements in or relating to elevator control systems
IPC: B66B1/18
Filed: 1935-11-27
Abstract: 460,805. Electric control systems for lifts. WESTINGHOUSE ELECTRIC & MANUFACTURING CO. Nov. 27, 1935, No. 32893. Convention date, Nov. 27, 1934. [Class 40 (i)] In a control system for lift cars wherein a car is controlled by calling means individual to each of a plurality of floors, means are provided to limit the number of calls to which the car will respond. Means also are provided for distributing the calls between a plurality of cars. Each car is provided with a set of buttons and indicators, and a common set of hall buttons is provided for all the cars. Operation of any one of the cars or hall buttons determines the floor to which the car is operated and also its direction of movement. Stopping of the car is brought about by the action of induction-plates mounted in the lift shaft operating in co-operation with relays energized by the control buttons and also a group of relays controlled in accordance with the car position. Selecting relays individual to the cars also are provided and are arranged to distribute the calls to the several cars. Quota relays also are provided to restrict the number of calls to which a car can respond to a predetermined number. Control by car buttons. Assuming the car is standing at a particular floor and that it approached such floor upwardly, "up direction" relay W, Fig. 2, is energized and the car buttons 2c, 3c, 4c are connected to contacts 2UP1, 3UP1, 4UP1 of the up car position relays, 2UP, 3UP, 4UP, Fig. 4, in preparation for up direction travel. One of these relays is energized in accordance with the position of the lift by a selector switch comprising up and down contacts a, b operated in accordance with the movement of the lift. The operated relay prepares the stopping circuit of the driving motor and operates the appropriate level lamp in the group 1UL . . 5DL Fig. 5. The car is started upwardly by operation of the master switch MS, Fig. 2, into engagement with the contacts MSU to operate " up reversing " switch U and relay M. When U operates, the generator 11 operates motor 10 and the car is moved upwardly at low speed. A relay V also is operated to short - circuit the resistance 30 and speed up the motor. Relay M opens the circuit of the operated lamp and prepares circuits for the conductor switch coils E, F. When the car approaches the floor corresponding to the depressed button, the stopping coil T is operated over the contacts of the button and the car position relay. The relay T energizes slow down inductor switch E which, when brought opposite an inductor plate in the shaft, operates its contacts to release relay V and slow-down the motor. Thereafter the inductor switch F is brought opposite a second plate and its contacts open to release relay M. Switch U also opens and the car is brought to rest at the selected floor. Release of M de-energizes the inductor switches E, F and completes a circuit for the appropriate up level lamps. Similar operations occur in the event of operation of a " down " button, but in this case the master switch is moved into engagement with the contact MSD and a switch D is operated to cause reverse operation of the motor 10 and to interrupt the circuit of up direction relay W and operate downdirection relay X. Moreover as the car leaves the top terminal floor the floor selector is reversed and the brush b is rendered operative to control the down position relays. Operated car buttons are held operated electromagnetically and are reset automatically at terminal landings by limit switches 31, 32, Fig. 2. Manual resetting also may be effected by button 33. Distribution of calls to various lifts. The car to which a call from the hall buttons is appropriated depends upon the position and direction of the several cars and is determined by car selecting relays S, BS, Fig. 5, individual to the cars and to groups of zoning relays 1UY ... 5DY, B1UY ... B5DY, Fig. 4, individual to the cars. The relays S, BS are operated by the contacts of the car position relays and are connected in parallel circuits with resistances 1SRU ... 5SRD, the arrangement being such that both relays cannot be operated simultaneously over the same series resistance. Thus when two lifts are at the same level both relays remain inoperative. To select a car in this event, individual button 34 is operated to permit energization of the corresponding relay and movement of the car away from that floor. Thereafter the action of the selecting relay is automatic and depends upon the position and direction of the car. When the first car moves away from the floor, the selecting relay of the second car is pulled up to permit operation of the zoning relay equipment of the second car. A bank of zoning relays 1UX... 5DX, Fig. 4, is provided common to all the lifts, the relays being operated by parallelly arranged contacts of the car position relays. These contacts in conjunction with the contacts of the car position relays control the groups of zoning relays 1UY .. 5DY, B1UY ... B5DY individual to the cars. As the first car travels upwardly the common zoning relays are operated in succession and in conjunction with the car position relays cuts out of circuit the zoning relays 1UY, 2UY.. corresponding to the floors passed and thereby excludes calls from those floors from the first car. If the second car remains at the first floor the corresponding relay in the common zoning group is operated and in conjunction with the operated car-position relay of the first car excludes calls from the second car from all floors except up calls for the floors between the two cars. Similarly after the first car starts downwardly down calls are excluded from the first car and included in those of the second car. In the event of a reversal of the first car at a floor intermediate the terminal floors all the up and down calls for floors above the first car are excluded from the zone of the first car and transferred to the second car. If one of the cars passes another car conditioned to travel in the same direction the overtaking- car transfers calls previously in the overtaken car to its own zone. The groups of zoning relays individual to the cars, control contacts in the circuits of groups of floor relays controlled by the hall-buttons 1UF ... 5DF, Fig. 3. The floor relays corresponding to the several cars are connected in parallel and the arrangement is such that operation of a button corresponding to a particular floor pulls up a floor relay of a car which is zoned for that floor. The floor relays control contacts such as 2DR1, 2UR1, Fig. 2, controlling the stopping relay T in a manner similar to that already described in connection with the car buttons. When the car stops at the selected floor contacts of relay M reclose and a resetting winding of the floor relay is operated. Selective resistances 1UR, 2UR ... are connected in series with each hall button and also in series with a plurality of branch circuits including the floor relays individual to the cars. Upon completion of any branch circuit the voltage drop through the corresponding resistance is such that a relay in the second branch circuit cannot be operated. With this arrangement two cars cannot have appropriated to them at any given time a hall call for the same floor and direction. Quota mechanism. Each car has a quota relay Q, BQ .. connected in series with contacts of the floor relays. When the munber of unanswered calls for a car reaches a predetermined number a corresponding number of resistance sections, e.g. 16, are short circuited and corresponding quota relay Q is operated. Operation of the quota relay prevents operation of further relays in the individual zoning group and this prevents appropriation of further hall calls to the car. The operated quota relay is reset when the car reaches a terminal station or reverses its direction or alternatively after the car has completed a complete trip by means of a limit switch 38. The system also is arranged so that the quota relay may be operated as soon as the number of calls appropriated to a car reaches the required quota although the number of unanswered calls may never reach the quota figure. This control is brought into action by switch 40 which connects into circuit retaining coils for the contacts of the floor relays controlling the resistance 16. The required quota may be varied automatically in response to varying traffic conditions, by a quota varying relay QR. Fig. 5, which is connected in series with a resistance 18 under the control of the floor relay contacts of the several cars. The relay QR varies the amount of resistance included in circuit with relays Q, BQ to vary the quota in accordance with traffic conditions.