Patent GB-1341433-A (GB)
Title: Elevator systems
IPC: B66B1/52
Filed: 1971-02-18
Abstract: 1341433 Elevator control HITACHI Ltd 18 Jan 1971 [16 Jan 1970] 2312/71 Heading B8L The operating speed of an elevator car is increased each time it passes through a floor position, until deceleration is required, and the lift is decelerated through the same set of operating speeds to rest. The selector, Fig. 1, comprises a tracer means 5, whose motion corresponds to that of the car on a reduced scale, upon which is mounted a control means 7, driven relative to tracer 5 and ahead of it in the direction of car motion by motor 11. Tracer 5 carries a pair of encapsulated solid-state oscillators 12L, 12R, acting with receivers 14L, 14R, see Figs. 4A-4C (not shown), to form proximity detectors for tracer 5, oscillators 13U, 13D, acting with receivers 15, see Fig. 8A (not shown), forming proximity detectors for control means 7. The relative displacement between means 5 and 7 is detected by oscillator (36) on the unit 7 acting with receivers (38U9- 38UI-38D9), Figs. 2A, 2B (not shown), on the unit 5. A zone position detector 43, Fig. 2A (not shown), detects the presence or otherwise of the control means 7 in a floor zone, and gives a digital output, see Fig. 3 (not shown), the floor plates (41) interfering with the feedback of an oscillator (39). Operation:-(a) Starting and acceleration (for example, from floor 1 to floor 5).-Pressing of call button (L5), Fig. 7 (not shown), in the car or at a landing supplies a gating signal to thyristor (THY5). Contacts (15C1-2), (15C3), Fig. 5 (not shown) close, and lift motion commences, moving tracer 5. Control 7 is driven ahead of 5 by motor 11, and as oscillator (39), Fig. 2A (not shown) moves past floor plates (41), the changing digital outputs E(O) and C(#) fed to logic circuitry (AND1-AND4, ME1-ME2) Fig. 5 (not shown) cause the successive firing of thyristors (THYA1, THYA2 ... &c.) increasing the speed of the lift for each floor passed, by successively closing relays (21F) ... (25F) ... &c., thus changing the value of resistance in series with the field coil of the generator in a Ward Leonard drive system. The waveforms existing in the circuit of Fig. 5 during this time are displayed in Fig. 6 (not shown). (b) Deceleration and stopping.-As unit 7 moves ahead of unit 5, contacts (15M1, 15M2 ... &c.) Fig. 7 (not shown) are successively closed, and when contact (15M5) closes, a circuit is completed via gated thyristor (THY5), causing unit 7 to stop and be locked by arm (29), Figs. 10A, 10B (not shown), held back by energized solenoid 19 during motion of 7. Energization of self holding relay coil (90C), Fig. 7 (not shown), enables, via contacts (90C-5) Fig. 9 (not shown) operation of the deceleration circuit of Fig. 9. As the tracer 5 catches up on the stationary unit 7 receivers (38U6, 38U5... &c.) Fig. 2B (not shown) pass oscillator (36), Fig. 2A (not shown), successively gating thyristors (THYU6, THYU5 ... &c.) causing the car to decelerate through the same speeds as during acceleration, see Fig. 11 (not shown). The precise stopping position is determined by a selector in the lift shaft (not shown). The relative positions of units 5 and 7 during the car movement are displayed in Figs. 10A-10C (not shown). Arm (30) is provided for downward movement, and as the car comes to rest, both engage one of mechanical contacts (B2 ... 9F) as appropriate, and are then both withdrawn. The positions of the oscillators 13U, 13D and receivers 15 respectively may be interchanged, so that resumption of operation after a power failure is immediate. Indication of lift position, and advance notice of lift arrival may be given.