PROXIMITY DETECTOR CIRCUITRY ESPECIALLY FOR LIFT DOORS

摘要

PCT No. PCT/GB82/00022 Sec. 371 Date Sep. 16, 1982 Sec. 102(e) Date Sep. 16, 1982 PCT Filed Jan. 26, 1982 PCT Pub. No. WO82/02536 PCT Pub. Date Aug. 5, 1982.Proximity detector circuitry of particular value in controlling the operation of elevator car doors. Sensors are set in the edge of the door. The outputs of the sensors are fed to one or more differential amplifiers which produce outputs dependent on the sensors. One such output may be compared in a further differential amplifier with its previous output slightly delayed in time and the results of the comparison used to actuate a door closing/opening control circuit. In addition large outputs arising from major differences in the sensors output may be fed (suitably attenuated) to the closing/opening control circuit.