Patent GB-1496349-A (GB)
Title: Elevator car call selection apparatus
IPC: B66B1/16
Filed: 1974-12-11
Abstract: 1496349 Selection apparatus HITACHI Ltd 11 Dec 1974 [12 Dec 1973 7 June 1974] 53521/74 Heading G3N In a logic circuit car selector, a signal SFST, enabling car response to a service command, being emitted upon coincidence between the location of a service demand on a car, and a stepped, advance floor signal CF 1 , the latter signal has; with respect to the originating floor (e.g. the second) of a current journey; the form of steps having levels F2F, F3F &c., representing at each time a distance ahead of the car exceeding the car's current stopping distance Cl 2 -Cl 1 , each of the levels F2F, F3F ... &c. representing also a floor ahead of the car, the level being stepwise increased at each of a set of predetermined times t 1 , t 2  ... after the starting time to, until the coincidence between the current level and a service demand is detected. The predetermined times are defined by generator SSG, and are preferably chosen to ensure that, at each stepping instant, the step signal represents the minimum possible car stopping distance, {i.e. CF 1  touches Cl 2  at t 1 , t 2  ... }, the generator SSG, using codes derived from the output states of registers (121, 122) receiving clockpulses (CP1), Figs. 8a, 8b, (not shown), ensuring that the required decrease in the stepping intervals t 0 -t 1 , t 1 -t 2  ... is provided, Alternatively the intervals may be made equal, or for each possible journey, the timings may allow for variable floor spacing. Generation of advance floor signal CF 1 ; Fig. 4 (not shown). Flip-flops, in number equal to the number of floors change state in sequence at each stepping instant, their outputs each corresponding to one of the levels, the sense of the sequence according with the motion direction of the car, a start signal pre-setting that flip-flop appertaining to the originating floor of the journey, from which floor the sequence is started. Alternatively, the start signal may pre-set a counter (DUDC), Fig. 10 (not shown), each of whose count states corresponds to a floor, the pre-setting being to a state corresponding to the originating floor of the journey, from which state, the counter is sequenced by the timing signals. The latter alternative may be included in a multi-car control system having a data processing system. Detection of the coincidence, Figs. 6, 11 (not shown). The signals representing the levels F2F ... of the signal CF 1  are fed to three groups of AND gates whose other inputs receive any stored, up, down or car calls respectively from the corresponding floors. Any coincidence leads to the generation of the enabling signal SFST. When the levels are represented by a counter state, units (DTC Fig. 11) for car, or up or down hall, calls, detect any coincidence. For a multi-car system, any hall calls have first to be allocated to a given car, logic circuitry, Figs. 3a, 3b (not shown) being provided for the purpose. Use of common timing signals for stepping the signal CF 1 , and a car acceleration control signal, Figs. 12-15 (not shown). In dependence on the journey length, one or more maximum speed signals (V M1 -V M  6  Fig. 12) are called up in a sequence, a set of generators, (Fig. 14), ensuring that the timing signal for stepping the speed command also steps the signal CF 1 . Facility is provided for the possibility that a single highest velocity level may be used for journeys of more than one length, an auxiliary timing signal (t 5  <SP>1</SP> Fig. 13) ensuring that the level reached by the signal CF 1  remains in accord with the journey length. Should the absolute maximum velocity (Vm 6 Fig. 12) be reached, signal CF 1  is stepped at constant time intervals corresponding to the inter-storey flight time of the car.