Patent GB-1468061-A (GB)
Title: Elevator system and method
IPC: B66B1/18
Filed: 1974-03-12
Abstract: 1468061 Multi-car control WESTINGHOUSE ELECTRIC CORP 12 March 1974 [12 March 1973] 10980/74 Heading G3N In a multi-car elevator system the processing of floor calls is under the control of a digital computer whose program comprises a set, Fig. 4 of sub-programs organised to run in a predetermined priority order, only those sub-programs being run as determined by the computer and its program on the basis of data received from the system. As shown, sub-program CSU assembles and stores car status data for the cars, including car travel and service directions whether any given car is in service, whether a car is by-passing floor calls, advanced position data, whether a car is in the process of responding to floor calls assigned to it, car weight, and door operation. Sub-program TNC reads floor call registers and, by comparison with the previous reading, detects new floor calls which are added to a call table, from which floor calls are deleted when responded to. TNC operates by scanning for up, then down calls, each in groups of 12 floors. Subprogram ACL functions as bidden by TNC to allocate a new floor call to the closest car to it, and having the correct travel and service direction for the call, provided such car already has floor calls assigned to it. Should any car enter, or leave service, or an unassigned car receive a demand to service a particular floor call under control of subprogram ACR, sub-program ACL functions to re-allocate all floor calls, being so bidden by subprogram CSU. If ACL cannot allocate a given floor call to a car already assigned to other floor calls, a demand signal for the floor call is created, and sub-program CSU bids sub-program ACR provided there is a car with no service demands on it. Under control of ACL and CSU, ACR allocates the closest such car to the call, the car moving directly to the floor, without intermediate service. Special attention is given to floor calls which have existed for at least a predetermined time. Sub-programs ACL, and ACR may work on the floor zoning principle, program ACL basically seeking busy cars serving the same zone as that of the new floor call. There may be a central express zone where no cars stop. The sub-programs operate iteratively, a timing arrangement ensuring this should it not arise from changes in system status, and any floor call allocated by ACL can be changed from one car to another, to keep with the closest car with appropriate service and travel direction. Any car from which an allocation is taken, provided no car or other floor calls are assigned to it, becomes available to be considered by ACR. The allocation remains with the car if car calls are registered in it, as well as being allocated to the other car. Subprogram CHECK, prepared for running by ACR may check for computer failure, and may prepare CSU for re-running. CHECK can disconnect the computer and a system processor, (11), Fig. 1 (not shown) if necessary. INTERRUPT 150 can stop the program if line voltage is low, or can do so at regular intervals to maintain a timing pattern. TIME sub-program 154 includes facility for timed car despatching from a main floor and can check for the existence of floor calls having existed for longer than a predetermined time. Adaptation of the system to a particular building is brought about by changing the software as appropriate the hardware being the same for all installations. The software may be changed if usage in a particular building changes, and can be changed to alter the criteria of car allocation.