GB1437780A - Elevator system - Google Patents

Abstract

1437780 Distance dependent slowdown control WESTINGHOUSE ELECTRIC CORP 17 May 1973 [17 May 1972] 02850/76 Divided out of 1436742 Heading B8L An elevator system includes means providing a distance dependent speed pattern during slowdown; wherein, for distances, of a car from a landing at which a stop is to be made, exceeding a transfer distance, the speed pattern is proportional to the square root of the distance to go to the landing, and, at the transfer distance, control reverts to a distance dependent signal provided by circuit 554 Fig. 12 responsive to hatch transducer (56, 58), Fig. 1 (not shown) comprising transformer (58), and, for each landing, induction plate (56) and; wherein, for each deceleration, a calibration takes place ensuring that the speed pattern for distances exceeding the transfer distance attains the , value required to avoid jerk at the transfer distance. Reversible counter 544 is counted up during car acceleration, the counting, under control of pulses developed by optical or magnetic detector (30), Fig. 1 (not shown) cooperating with a perforated pulley (26) driven by the car; being stopped at attainment of maximum speed. During decleration, as the counter is counted down to binary twenty, its output, via d/a converter 960 controls circuit 964 whose analogue output, in view of multiplier 984 in the feedback of amplifier 982, is proportional to the square root of the count, leading to constant, distance dependent deceleration. A logic circuit ensures that d/a 960 receives the count twenty should the actual count fall below this. The deceleration signal is fed to output DSAN, whose lowest value is preset at point 1014, and communicated during acceleration to capacitor 1028, to be passed from there to terminal DSAN during distance dependent car deceleration to control the car at lower speeds, thus reducing accuracy requirements for the analogue circuit. Decleration characteristic is preset in unit 976, 1000. Attainment of the minimum output of counter 544 causes car control to switch over to hatch transducer circuit 554 Fig. 12, controlling the last part of car movement to a landing. Control of car speed profiling overall is performed by driver 552, see Fig. 21 (not shown), controlling analogue switches 548, 550, 556 and 560, the latter being switched discontinuously, or providing a blend of signals TRAN/DSAN; DSAN/HTAN during a switchover period. The Specification discloses a terminal slowdown device, described and claimed in Specification 1,436,741. Features of the floor selector disclosed herein are described and claimed in Specification 1,436,743. Means for providing a jerk controlled speed pattern signal during acceleration, and constant speed phases of car motion are described herein, and claimed in parent Specification 1,436,742.