Patent GB-1484499-A (GB)
Title: Control apparatus for elevators
IPC: B66B1/20
Filed: 1974-12-18
Abstract: 1484499 Automatic elevator control HITACHI Ltd 18 Dec 1974 [19 Dec 1973 20 Feb 1974] 54645/74 Heading G3N In a multicar elevator control system, means are provided at each lobby to detect the number of would-be passengers, and hence to estimate, for each lobby, the number of such passengers for up, and for down directions, such information being used in the allocation of hall calls to the cars. If, at a given hall, only an up, or a down demand for service is made, the detected number is allocated solely to the registered direction, otherwise the detected number is split in a predetermined manner between up, and down directions. As shown, thenumber of would-be passengers is detected by photosource and detector pairs BP1, BR1; BP2, BR2, a network, Fig. 2 (not shown) including delay timers and memories ensuring that only persons entering the lobby area, H are counted. Should calls for both directions be registered from the lobby, a signal representing the count is divided according to settings of potentiometers (r D , r U ) Fig. 4 (not shown) to provide the estimates (PUF, PDF) of the numbers awaiting up, and down service. In the presence of demand for one direction only, the signal passes undivided to provide the signal (PUF), or (PDF). Multiple taps on the potentiometers, Fig. 5 (not shown) enable the dividing to be varied with traffic conditions, to suit, up or down peak, lunchtime, or normal service, modes of operation, the precise division ratios being individually set for each lobby. Setting division ratios; Figs. 6-9 (not shown). For each floor and direction of movement, the number of passengers entering each car is detected and added for all cars the resultant, for each mode of operation being accumulated in counters (CFU1, CFD1, CFU2, CFD2; or CFU3, CFD3 Figs. 7, 9), signals (SPU, SPD), representing, for any mode, the proportion of the total stored count relating to up, or down, traffic respectively, being passed to multipliers (MU, MD Fig. 8), of the signal (dWF) representing the number of would-be passengers, the multipliers providing the estimates (PWFU, PWFD) of the up, and down demands for service whenever demand for both directions is present. The counters may be reset at predetermined intervals, or whenever the character of the demand changes. At times of light traffic, as sensed by comparing the aggregate storage of the counters for any one mode with a predetermined value (VCM Fig. 9). The inputs (SPU, SPD) to the multipliers may be pre-set values (VSU, VSD). The number of would-be passengers may alternatively be detected by mat switches, each occupying an area occupied by one person, or by ultrasonic sources and detectors or by a TV camera, the number entering a car being detected by photo-cells, or as the new less the old content of a car at the floor. Use of the estimate in multi-car control, (i) Figs. 10-23 (not shown). Normally, the cars are regarded as moving in a ring, and each car has allocated to it all hall calls between its notional position, and that of the preceding car in the ring, the notional position being advanced 0, 1, or 2 floors ahead of the actual position in dependence on the distance to the succeeding car and the demand on the car in relation to the average demand, (Figs. 12-17). For a given car, for each hall call allocated to it, the estimated number for the car's direction appertaining to the particular hall is added to the estimates for hall calls already allocated to it, and to a signal representing the number of passengers already in the car. Should the resultant estimated total demand exceed a predetermined limit (VA Fig. 23) signal (XA Fig. 17) is provided, and prevents the car from accepting any more hall call demands, subsequent hall call demands in the car's erstwhile zone being allocated to the succeeding car. In an alternative embodiment; (ii) Figs. 24-28 (not shown). The floors are grouped into regions Z1-Z4, each including either a lobby, upper terminal, or lunch floor, and, whenever a  given car's position or notional position is within a region, and the estimated total demand exceeds the predetermined limit (VAZ Fig. 28), the car will no longer accept hall calls from within the region, but will accept them from floors outside the region, but otherwise in the car's zone for service. The zone of the succeeding car is expanded to include the floors of the region. The predetermined limit (VA), or (VAZ) may be varied to suit the particular region and/or mode of service. The estimated total demand signal may be used to modify car response for systems in which a hall call would normally be allocated to the nearest car, or the first car to reach a deceleration point for the floor, a car with estimated total demand exceeding the limit not responding to the hall call. The control system may be embodied as a computer and digital circuits.