Patent GB-1436743-A (GB)
Title: Elevator system
IPC: B66B1/46
Filed: 1973-05-02
Abstract: 1436743 Floor selectors in elevator control systems WESTINGHOUSE ELECTRIC CORP 2 May 1973 [17 May 1972] 20910/73 Heading B8L  The floor selector 34 in an elevator control system, Fig. 1 (not shown), comprises three binary counters 70, 72, 80 and comparators 82, 76 controlling a logic circuit 84 including a synchronizer, and call selector (94, 92), Fig. 3 (not shown), providing signals to speed pattern generator (48, Fig. 1) controlling car movement. Binary scan counter 80, under control of a timer (not shown) counts from zero to a predetermined number at least equal to the number of landings, its count being compared with that in reversible coarse position counter 72 whose count at any instant represent the closest floor ahead of the car at which it can stop. At equality of the two counts a signal EQ1Z, identifying a timing slot in the counting period of counter 80 appertaining to the above closest floor passes to unit 84. Reversible counter 70, receiving pulses from optical or magnetic pickup (30, Fig. 1) detecting openings in pulley (26) supporting cable (24) fixed to the car counts up, at twice the pulse reception rate during car acceleration, so that its count represents a continuous position ahead of the moving car in the shaft, representing the closest shaft position ahead of the car at which it can stop. The output of coarse position counter 72 is fed to readonly memory 74 comprising for each floor a set of diodes which are selectively fused out during system construction so that, for each floor position input from 72, the memory 74 provides an output representing the position of the floor in the structure on the same distance scale as represented by the output of counter 70. Upon equality being detected between the outputs of units 70, 74, in comparator 76, indicating that the car has reached the precise position at which deceleration must be initiated if s stop is to be made at the floor represented by the count of 72, a signal EQ2 is passed to logic unit 84. A call selector (92), Fig. 3 (not shown), in unit 84 receives any car, or corridor call signals (1Z, 2Z, 3Z) serialized into the time slots appropriate to their location, and if such call signals coincide with the signal EQ1Z indicating approach of the car to a floor requiring service, synchronizer (94) is set so that, at the moment signal EQ2 is received, signals controlling car deceleration and enabling door control and hall lantern illumination are emitted, memory (90) identifying the counts of (80) not associated with any floor. Counting of unit 70 is simultaneously disenabled, so that when the car comes to rest, its count represents the actual car position. Logic circuit (96) has facility to ensure that if car load exceeds a predetermined maximum, hall call response is disenabled. If, at the emission of signal EQ2, there is no coincidence in EQ1Z and (1Z-3Z) timing slots, a signal passes to indexer 78 increasing, (or decreasing for the opposite direction of car motion), the count stored in 72 to represent the next floor ahead of the car. At the top, bottom, and main floors, counts in 70 and 72 are both reset to preset values, to correct for any residual errors, by unit (86, Fig. 3) containing binary representations of such floor positions in readonly memories. Minimum/maximum decoder (88, Fig. 3) passes a signal to synchronizer (94) ensuring that car slowdown takes place at top and bottom floors irrespective of any demand for service there. Selector circuitry is disclosed in detail in relation to Figs. 4-11 (not shown). The car serves upwards to the highest call for downward sarvice at which it reverses in the absence of higher calls, and to the lowest call requiring upward service in the downward direction, in the absence of lower calls. Inductor plates (56, Fig. 1) co-operating with transformers (58) on the car, control stopping and levelling, pick-up (60) and toothed blade (62), see also Fig. 19 (not shown), providing a pulsed output, detecting overspeed near the terminals, such signals being fed to speed pattern generator (48) disclosed herein, and claimed in copending Specification 1,437,742. The terminal slowdown control within the speed pattern generator 48 forms the subject of copending Specification 1,436,741.