Patent GB-1433941-A (GB)
Title: Elevator control systems
IPC: B66B3/02
Filed: 1973-04-17
Abstract: 1433941 Automatic control of elevators HITACHI Ltd 17 April 1973 [19 April 1972 19 May 1972 26 May 1972] 18389/73 Heading B8L In a multi-car elevator system, zoned for the allocation of hall calls to the cars, each hall call being allocated only to a car whose service zone includes the call, the zone boundaries at maximum corresponding to the car effective positions, the forward extent of each car's service zone is limited, in dependence on predetermined parameters of system operation. The cars are regarded as moving on a ring U-#D-#U. The forward extent may be constant, or may be varied as a function of the following parameters: the distance of a car from the succeeding car and the extent to which its allocated hall call load exceeds the average; the load on the car; the time of day, e.g. a.m., or p.m. peaks, forward extent of upward zones being decreased, that of downward zones increased for a.m., and vice versa for p.m.; expected heavy service demand to a specific (e.g. conference room or cafeteria) floor, forward extents towards it being diminished in size, forward extents away from it being increased in size. The landings may be divided into areas, and in dependence upon the relative demand for hall call service from the respective areas and the position of each car, the forward extent is automatically adjusted. In Fig. 7 (not shown), a hall call allocation circuit, the car position signal (e.g. F2UA) is additionally fed to an inhibit element (IN9UA4) seven floors ahead, so that, should no preceding. car be within seven floors ahead of, say, car A, no hall call can be allocated to the car beyond seven floors from the position signal. To establish the effective position, signals (EOA, E1A, E2A), one of which is present, cause the "position" of the car for allocation purposes to be advanced 0, 1 or 2 floors in dependence; Figs. 2-6 (not shown); on the distance between the car and the succeeding one, and its allocated hall call load compared with the average, giving forward extents of 7, 6 or 5 floors respectively. In Fig. 12 (not shown), (1N9UA4) receives the signal (f2UA) derived from OR (02UA3), so that the forward extent is always 7 floors regardless of signals (EOA-E2A). In Fig. 13 (not shown), the forward extent is set by device C (a diode matrix) which receives car position signals, and mode signals (S 1 , S 2 - S i ), which are set manually, or by a time switch to modify the forward extents for a.m., or p.m. peak, or heavy service to a specific floor. Individual cars can be set for distinct forward extents by corresponding choice of the set (S 1 -S i ) for each car. Alternatively the set can be defined by and changed in response to changes in the loading of each car, Fig. 14 (not shown), or the signals (EOA-E2A) may themselves cause changes in the values of (S 1 -S i ). In a fourth embodiment, the landings are divided into areas, Fig. 15 (not shown), and the number of hall calls in each area is compared with the average over the areas of hall calls (Figs. 16, 17) to produce, for each area a triplet of signals (e.g. 1Z 2 , 1Z 1 , 1Z 3 , Fig. 17) which, together with car position signals are fed to a logic circuit, (Fig. 18), whose output controls the forward extent accordingly, being fed to allocation circuit (Fig. 19). Hall calls outside any zone remain unallocated until they fall within a zone of a car. Consequent upon allocation, one or relays (Ry-, Fig. 10) is actuated, to enable car deceleration, and operate a landing indicator light (S; Fig. 11).