Patent GB-723533-A (GB)
Title: Improvements in or relating to control systems for lifts and the like
IPC: B66B1/18
Filed: 1952-08-07
Abstract: 723,533. Automatic lift systems. EXPRESS LIFT CO., Ltd., and HUNT, S. T. Aug. 7, 1952 [Aug. 17, 1951], No. 19491/51. Class 40 (1) A control system for three or more lift cars serving multiple floors in which each car is arranged to, return to a parking floor comprises winding control mechanism for causing each car to move up or down, destination switches operable in each car to select a required floor, apparatus associated with each car for registering and storing outstanding calls from the destination switches of that car and for conditioning the winding control apparatus to stop the car at the preselected floors, floor call switches at each of the multiple floors, apparatus common to the several cars for registering and storing outstanding floor calls and for allocating starting preference from the parking floor upon registration of floor calls after the passage of the preceding car or which have been left unanswered and passed by the preceding car, to that car which first returns to the parking floor, or which is next in succession at the parking floor, the apparatus being such as to condition the winding motor control mechanism of the next despatched car to cause it to travel to and stop at all such unanswered or passed floor calls as well as those floors for which calls have been registered in the appropriate car destination switches. Construction. In the despatching control circuits for each of the three cars of a multifloor lift system of the kind described in Specification 538,476 wherein a car is started in response to a floor call switch or a car destination switch (not shown) by operation of the appropriate start relay WSR1, WSR2 'or WSR3, the relay WSR1 is energized in series with relay contacts 1GB1  closed when the car 1 is parked and relay contacts SR1 closed when that car start relay is operated. In parallel across the latter series relay contacts are three further sets of relay contacts SA1, SB1 closed by start preference relays WSA1, WSB1, and contacts 711 held closed when unanswered calls are registered from above the car. The combination of switching contacts is connected in series with two groups of four parallel switching circuits comprising in the first group relay contacts 83B2 open when the car 2 is travelling up or has last travelled up and closed when it has travelled or has last travelled down in series with relay contacts 712 closed when a floor call exists from above the position of car 2, relay contacts PP2 closed when a passenger in car 2 wishes to pass a floor at which the car would otherwise stop, relay contacts 612 closed when an up call exists from a floor which has been passed by the car 2, relay contacts T622 open when car 2 does not respond to a higher floor call within a predetermined time; and in the second group an assembly of parallel switching relay contacts 713, 83B3, PP3, 613, T633 operated under similar conditions in response to the movements of car 3. The winding of a start preference transfer relay WSP1 for car 1 is energizable in serieswith a chain of relay contacts 232 closed when car 2 is parked, T62 closed when car 2 does not respond to a higher call within a predetermined time, and SP2 normally closed when car 2 is taken out of service; in parallel with a similar chain of relay contacts 233, T63, SP3 operating similarly for car 3. Master contactor 671 in series with winding WSP1 closes when car 1 is removed from service. Start preference relays WSA1, WSB1 in series respectively with relay contacts SB2, SB3 opening when cars 2 and 3 have obtained starting preference are energizable over a switching group comprising normally closed relay contacts SP1 of the first car transfer relay WSP1 in parallel with series relay contacts 1GB22 and 1GB33 respectively opening when cars 2 and 3 are parked, relay contacts T6A1 opening if car 1 fails to start within a predetermined time of a call, relay contacts IGB11 closed when car 1 is parked, and relay contacts 48B1 normally closed but open when car 1 is in motion. A signalling gong G1 is operable by the charging current through a rectifier S162 into condenser C131 and energization of starting relay WSRI opens contacts SR11 to disconnect the discharging resistance R131 and contacts 2SR1 to complete the gong circuit over disabling switch 1GB1 which is only closed when the car is in charge of an attendant. The starting relay WSR1 is alternatively energized through relay contacts 1GB1, relay contacts T6A1 which are normally closed but opening if car 1 fails to start within a predetermined time, and relay contacts CP1 closing on operation of any destination switch of car 1; in parallel with relay contacts 39B1 closing when car 1 starts. Switching circuits arranged and operating in similar manner are provided to control the operation of cars 2 and 3 of the system, in which the individual components bear similar numerical references, with the suffixes 2 or 3 instead of suffix 1. Operation. Initially the cars are assumed to stand at the parking floor, and the earliest arrival (e.g. car 1) is given starting preference by energization of its relays WSA1, WSB1 from the D.C. bus bars over contacts SB2, SB3 (closed since the relays WSB2, WSB3 of the other cars are inoperative), normally closed contacts SP1 in parallel with contacts 1GB22, 1GB33 (normally open but closed when cars 2, 3 are away from the parking floor), contacts 48B1 (closed since car 1 is stationary), contacts 1GB11 (closed since car 1 is parked) and normally closed contacts T6A1 which open if car 1 fails to start for any reason. The next arrival at the parking floor (e.g. car 2) has only its start preference relay WSA2 (in its associated control switching circuit) energized since relay WSA1 has already operated to open contacts SA1, while car 3 on arrival has neither of its start preference relays WSA3, WSB3 energized, since contacts WSB1, WSA2 are both opened by energization of relays WSB1, WSA2. The registry of a floor call or destination call closes contact 711 and completes a circuit from the D.C. bus bars over the already closed contacts SA1, SB1 and contacts T622, T633 of the parallel banks of switching contacts operated in response to cars 2 and 3 to energize the start relay WSR1 of car 1, which accordingly moves off. Contacts 1GB11 open to release relays WSA1, WSB2 and contacts SA1, SB1 close to operate relays WSB2, WSB3 so that the car 2 is marked as the next for despatch by the operation of relay WSB3. Registry of a call by the car switch of car 1 closes contacts CP1 to similarly energize start relay WSR1 over normally closed contacts 1GB1 and T6A1 so that the car moves off to close contact 39B1, and cars 2 and 3 are marked in order as the cars for subsequent despatch as described above. If the marked car 1 fails to move off within a predetermined time of a floor or car switch call energizing its operating system, contacts T6A1 are opened to de-energize the start preference relays WSA1, WSA2 so that the start preference is transferred to the next car marked for departure. The driving mechanism of the respective cars may be controlled in known manner to cause them to stop in sequence at successive floors pre-selected by car switches or floor call switches when the cars are moving in such a direction as to enable them to answer such calls. When an up call is registered below an upwardly moving car 1, contacts 611 are closed to energize start relay WSR2 of car 2 over contacts SA2, SB2 closed by start preference relays WSA2, WSB2; contacts 712 closed by the existence of a floor call above the second car, contacts 713 closed by the floor call existing above the third car, and contacts 83B3 closed by the parked third car. Car 2 is despatched at once, or after a time delay provided to avoid car bunching, or if the system is arranged for attendant operation gong G2 is sounded on contacts SR22 opening and 2SR2 closing, as a starting signal. When further floor calls are inserted behind the lowest up car or highest down car, the car 3 is despatched by energization of relay WSR3 over contacts SA3 and SB3 closed by energization of start preference relays WSA3, WSB3 of the car 3, contacts 713 closed by the existence of unanswered calls registered above car 3 and contacts 611, 612 closed by the existence of calls passed by cars 1, 2; the start preference relays of each car absent from the parking floor being released by opening contacts 1GB11, 1GB22 or 1GB33 as appropriate. Although described for a sequence of arrival and departure in the. order car 1, car 2, car 3, the system operates similarly for any car sequence and is extensible to a plurality of cars exceeding 3. One or more cars and the associated driving apparatus may be shut down when traffic is light (e.g. car 1), in which case contacter 671 closes to energize start preference transfer relay WSP1 to transfer the start preference to the next available car of the sequence.