Patent GB-1420133-A (GB)
Title: Elevator control system and process
IPC: B66B1/18
Filed: 1973-01-30
Abstract: 1420133 Automatic control of elevators HITACHI Ltd 30 Jan 1973 [2 Feb 1972 21 Feb 1972 8 March 1972] 4677/73 Heading B8L In a multi-car lift control system, cars are dispersed to stand-by floors, and each car on stand-by has as its zone of response to hall calls, all floors between itself and the floor adjacent to the nearest cars, as shown by the arrows. Consequent upon a demand for service, say from car B, when a direction, say down, of motion is established, car B's former upward zone is taken over by the nearest car ahead, C in Fig. 3 (not shown), and as car B moves off, the nearest car behind, A, has its downward zone extended behind car B, Fig. 4 (not shown). Should the car D, on stand-by at the basic stand-by floor, which may be the ground floor, or any other floor originating heavy hall call traffic, leave such floor the former downward zone of car C is extended around from and including the basic floor, as in a ring, to the floor immediately below the nearest car above, Fig. 5 (not shown). Any car serving within its own zone remains set for stand-by within the zone, but, should it leave the zone, the standby setting for the car is transferred if possible a car already in its zone and able to go to the standby floor, for example, F, on service in the zone of A which moves out of its zone, takes over the zone of A, Figs. 6, 7 (not shown), or otherwise a car, such as E, neither on basic floor standby nor providing a service is despatched to standby in the vacated zone. Car A, after serving, then returns to the basic standby floor (Fig. 7). However, if the M-G sets of all cars at the basic standby floor are off (the M-G set of any car being normally off if no demand for service has existed for a predetermined time), a car can serve outside its stand-by zone and return to standby therein. Should all cars, DEF, at the basic floor leave to provide service the standby of cars A, B, C, are cancelled and they return to the basic floor, cars, D, E, F, after serving, being allocated to standby at the other standby floors. However, if A, B, and C's M-G sets are off, cars D, E, F will return to the basic floor. Should any car become fully loaded, its zone is taken over by the cars ahead and behind it, such car thus not responding to hall calls. Response to complete shut-down of individual cars, due to faults or repairs.-To ensure that at least two cars are normally at rest at the basic floor, the number of upper standby floors is progressively reduced. For one car shut down, no change is needed, Fig. 8 (not shown), but for two resp. three, cars shut down, one resp. two, upper standby floors no longer have cars standing by, Figs. 9, 10 (not shown). Busy traffic mode, defined as a substantial equality of up, and down demands, and higher traffic. Under these conditions, one of the upper stand-by floors is eliminated. Cars may standby at 5th and 7th floors, or such specific floors may be changed to 4, and 5 or 6, resp. The control system, using relays, some of which are delayed in their action is disclosed in relation to Figs. 11-16 (not shown), cars being automatically dispersed to the standby floors at system switch-on.