Patent GB-1416710-A (GB)
Title: Elevator systems
IPC: B66B1/18
Filed: 1972-12-06
Abstract: 1416710 Lift cages &c WESTINGHOUSE ELECTRIC CORP 6 Dec 1972 [6 Dec 1971] 48682/72 Heading B8L In a multi-car system in which, for downward service, the floors are divided into zones Z0-Z3, Fig. 3, cars conditioned for downward service are assigned in response to down service demand in a zone below, only provided that they are neither slowing down, nor stopped at a landing. As shown in Fig. 3, car G is assigned to the down call in the zone Z2, since car A is loading, and car F is assigned to the down call in zone Z1, since car B is slowing to serve the fourth floor. A similar assignment procedure may operate for upward calls. Control apparatus, Fig. 1.-For a three car system. A car assignment enabling relay ZD is energized whenever the total resistance of chain R25-R28; normally shunted by closed contacts K0-3-K3-4 which respectively open whenever a demand for service in zones 0-3 respectively is received; is greater than the resistance in chain R30-R34. Resistors R32, R33, R34, corresponding to cars A, B, C are each in parallel with a network containing normally open contacts, for car A, (i) of a relay KB energized unless car A is conditioned for down travel and a zone demand below is registered, (ii) of relays X and G energized when the car is serving downwardly, and when the car is approaching a floor for which a car call is registered, and (iii) normally closed contacts FA11 of a relay FA, enabled by the energization of relay ZD, and itself energized when the car has been assigned, and (iv) contacts DS3, closed when the car doors are open. Resistors R32-R34 are thus in circuit whenever the corresponding car is neither slowing down, nor stopped and is either in position to answer a zone demand, or is assigned to a zone demand. Operation.-Demand for down service from a hall in a zone causes a respective one of contacts K1-K5, K2-K5, K3-K4 to open, causing the insertion of resistance into the circuit R25-R28 energizing relay ZD. Assuming contacts KB2 are closed indicating that the corresponding car is not travelling down to a zone demanding service, relay ZD enables relay FA, and, should car A be assigned to the demand, via assignment circuitry (not shown), contacts FA11 open, the insertion of resistance R32 causing de-energization of relay ZD. If a car is in the zone above the demand, since then contacts KB2 are open, relay 2D is not energized, there being a car in position. However, whenever down preference relay contacts X12 are closed, together with either of contacts G2 or DS3, the resistance R32 is always shunted, removing the possibility that the car A can be assigned to the zone demand, contacts G2, DS3 being closed respectively when the car is slowing down, or stopped at a floor with its doors open. Relay ZD is thus energized whenever the number of zone demands exceeds the number of cars assigned to serve them. In a development, Fig. 4 (not shown), a car arriving at the topmost landing is able to be considered for assignment to serve specific down landings, by shunting the contacts W7 of up preference relay W by contacts (T21), closing when the car is at the upper terminal, (TLW) closed when the car load is less than half of the maximum, and contacts (ZD8), of the relay ZD, closed when the number of zone demands exceeds the number of available cars. Such a facility is provided when the topmost floor is a transfer landing, cars moving downward therefrom normally satisfying car call demands. Contacts (TZ2), closed when the car is at the top floor, enable the registration of any car call, for example via contacts (6CR2), via diode DX, to operate reversal relay (69H), changing an up preference setting to a down preference one without the need for any down corridor call to be registered. The circuits disclosed are adjunct to those of U.S.A. Specification 3,256,958.