GB1495393A - Elevator system with object detection means - Google Patents

Abstract

1495393 Control of D.C. motors WESTING- HOUSE ELECTRIC CORP 9 Dec 1974 [18 Dec 1973] 53092/74 Heading H2J [Also in Division E2] An object detection door control mechanism for a lift car door comprises two object detection means either of which is designed to stop door movement when actuated: the first means involves a radiant energy (preferably infra-red) source (60, 64) mounted on the door and directed at a sill portion 74 of the entranceway and a detector means (62, 66) on the door directed at the sill portion; the second means comprises a ribbon switch (KS1, RS2) located along the door edge. As shown centre-opening sliding doors 5, A5 are moved by an electric motor 25 via a lever-and-link mechanism and each door is provided with detection means as described. The surface of the sill portion 74 is designed to scatter the reflected radiation (i.e. rough bronze or aluminium oxide in epoxy resin binder) and the detector means intercept only that radiation scattered parallel to the door edge. Each detector means includes inner (D2, D4) and outer (D1, D3) detectors which respond to radiation from separate T1, T2, T3, T4 transmitters to define inner R70 and outer R68 beams and as the doors near closure limit switches L1, L2 are actuated in turn by cam C1 to render first the outer, then the inner detectors inoperative. The ribbon switches (Fig. 3) comprise spaced conductors 200, 202 set in a plastics or rubber jacket 204 and are connected (Fig. 4, not shown) such that when pressure on a switch causes contact of the conductors, a relay (222) is de-energized to open contacts 224 controlling the safety relay DR in the motor control circuit shown in Fig. 5. A spacer 208 prevents the switches actuating each other in the closed position. The circuit of Fig. 5 is the same as that described and shown in Fig. 4 of copending application 53091/74 Serial No. 1,495,392, except for the omission of the monitor relay (M) and the sources (120, 122) controlled thereby and the replacement of the detector contacts (C102, C104, C114, C116, C112 C112<SP>1</SP>) and the limit switch (108) by the contacts B1 ... B4 of detectors D1 ... D4 and limit switches L1, L2. The latter detectors and switches are similar to those described in copending application 53093/75 Serial No. 1,495,392, whose motor control circuit omits the ribbon switches and the relay 222, 224. The switches L1, L2 operate sequentially during door closing to cut out detectors D1 ... D4 when the doors reach the point where reflection from the sill will be interrupted by the opposite door section. Opening of contacts 224 de-energizes relay DR to provide back-up protection should the detector system fail in a mode permitting the doors to operate. Contacts 224 may be shunted by switch L2 or may (with member 222) be replaced by a solid state relay.