Patent GB-538476-A (GB)
Title: Improvements in electrical systems of control for lifts
IPC: B66B1/18
Filed: 1939-12-29
Abstract: 538,476. Push-button lift systems. EXPRESS LIFT CO., Ltd., and HUNT, S. T. Dec. 29, 1939, No. 33010. [Class 40 (i)] In a two-car collector type system in which, when the cars are in use, a landing call is answered by the nearer car travelling towards the calling floor in the direction in which the caller desires to travel. An idle car can travel in either direction to answer a call. For purposes of explanation it is assumed that both cars run in the same direction round an endless track, up calls being stored on one side of the track and down calls on the other. When the cars are in use each car answers only those calls stored in a zone between it and the other car in the direction of travel, but when a car becomes idle it can be considered to be on either side of the track. For example, as shown in Fig. 13, an up call U at floor 7 and the down calls D at floors 6 and 3 are all in the zone of car X but if car Y deposits a passenger at floor 4 and becomes idle it can be considered to be transferred to the down side of the track and then takes over the down call at floor 3. The control is exercised by call storage and position- and direction-indicating equipment individual to each car and by common co-ordinating equipment shown in Fig. 9c. Normal response to landing call.-In the control equipment of each idle lift there are energized G, Fig. 6, provided all the landing contacts and the car contacts are closed, one of the floor relays PA ... PH selected by a switch of the kind described in Specification 432,606, [Group XXXVII], according to the position of the car, LA, LB, LAA, LBA, Fig. 7, US, Fig. 6, (unless the car is at the top), DS (unless the car is at the bottom), and TC, Fig. 8. Operation of an up or down landing push energizes in each lift equipment the corresponding one of a number of callstoring relays UB ... UH and DA ... DG, Figs. 2 and 3, and this relay locks in series with a relay LT and releases LA or LB according as the floor at which the call is made is above or below the present position of the car. BU or BD, Fig. 7, is thus operated and LAA or LBA released and BUA and BUB or BDA and BDB, Fig. 8, are operated. BUA if operated, energizes one of relays HA ... HH, Fig. 9c, common to both lifts, corresponding to the present position of its car and BDA if operated similarly operates one of the relays KA ... KH. Each lift is thus represented by an energized relay HA ... HH, KA ... KH. These relays open points in a chaincircuit to which the individual car-allotting relays JX, JY are connected by BUB or BDB according as the floor from which a call is received is above or below the car, the point of connection being determined by the energized floor relay PA ... PH of the lift concerned. At the same time, battery is connected to another point in the chain according as the call is an " up " or " down one and according to the floor at which it is made. The arrangement is such that for an " up call the relay JX &c. of the nearer car below the calling floor is operated and for " down " calls the relay JX &c. of the nearer car above the calling floor. The other relays JX &c. are not energized because their circuits are opened at the K or H contacts. If all cars are below a " down " call or above an " up " call the relay corresponding to the nearer car is actuated. JX &c. on operating energizes the " up or " down indicator relay MB ... MH or NA ... NG, Fig. 10, of the floor concerned. The starting relay AU (or AD) of the selected lift being no longer short-circuited by JX and BUA or BDA energizes the " up " contactor YM (or " down " contactor DM) and relays E (on " up " calls), A, TA, Fig. 6, and TB, Fig. 8 are operated. Between floors, contacts JA 1/2, ZA 7/8 are actuated temporarily to step on the switch SW. The consequent change of condition of relays PA ... PH between the calling floor and the preceding one causes LA (or LB) to be re-operated followed by LAA (or LBA). SL also is operated, and slows the lift down and energizes LP which holds the operated indicator relay, the original circuit of which has been opened by the change in condition of HA ... HG, KA ... KG. SL also energizes a releasing winding of the calling relay whereupon JX (or JY) is released. When the floor is reached, relay S is operated, UM, A, TA, AU are released and the lift stops, SL, T, B, BU also are released. Special cases.-(1) If, in response to car calls, the car originally answering a landing call is passed by another car, the latter car takes up the landing call. Assuming the X car to take the call, JX energizes the appropriate indicator relay and the car proceeds to the point indicated by the car button. Here it is overtaken by the Y car and when the latter reaches the next floor the relay JY operates and the circuit JX is opened by the relay HA ... HH or KA ... KH corresponding to the position of car Y. The indicator relay of the X equipment falls and that of the Y equipment pulls up. (2) Similarly, a call is transferred if a car becoming idle is nearer to it than the car originally answering it. (3) If cars X and Y are both at the same floor, relay P in one or other of the equipments is operated according to the position of switch PS and ensures that only one of the relays JX, JY is operated in response to a call. (4) If the proper car fails to start, the call is transferred. On the operation of JX (or JY) the corresponding relay TC is cut off but if the contacts UM operate correctly, relay A prevents release of TC. If TC does fall, however, it releases the relay KA ... HH corresponding to the X car position and thus releases JX and energizes JY. (5) If simultaneous calls are received involving reversal, e.g. if down calls are made at floors 5, 6 and 7 with all idle cars below these floors, the calls are taken by the nearest car and the most remote call is answered first. When the car approaches the nearest of the calling floors, a circuit is partly made by the P and D (or U) relays of that floor for SLA but is held open by the D (or U) relays of the calling floors beyond. When the furthest call is reached SLA energizes SL and the lift stops as previously described. Details. (1) If the position of the switch SW does not correspond with that of its car, the arrival of the latter at a terminal floor and the consequent release of DS or US completes a self-interrupting circuit for one of the driving magnets DMU, DMD and the switch moves to a terminal position. (2) Preventing control of occupied lift by floor calls. Wnen the lift is occupied, a relay FS, energized over a floor switch, holds the sluggish relay TB after its circuit has been opened by TA to prevent operation of the lift motor until the passenger has operated the appropriate car push and CT has consequently been operated. (3) Up and down floor lamps are lit by relays MB ... MH, NA ... KG controlled over a chain of contacts of the relays HA ... HH, KA ... KH which indicate the position of the car during up and down travel respectively. A lamp is operated in response to a call only if the next arrival of the associated car will be appropriate for answering the call. If, for instance, up and down calls are registered at floor 5 and the car is rising to answer a call at floor 6, only the up lamp will glow at floor 5.