Patent ID: 6247558
Filing Date: 2001-06-19
Classification: G01V

Abstract:
Apparatus for reducing power consumption in a elevator door protection system,the elevator door protection system having an infrared curtain comprising one or more infrared beam transmitters which provide a beam or beams across a elevator door opening, one or more infrared beam receivers for receiving the beams; circuitry responsive to an output of the receivers when the beam or beams are intercepted by an object in the elevator door opening, whereby the circuitry produces a drive signal; and elevator door control circuitry responsive to the drive signal for opening the door or doors in the event of beam interception;the apparatus for reducing power consumption comprising detection circuitry which responds when (a) the elevator door or doors are substantially closed, so that the usual power supplied to the transmitters can be reduced; and (b) the elevator door or doors are opening, so that the usual power supplied to the transmitters can be restored, and wherein the transmitters and receivers are normally scanned at a rate of N per second and power is reduced by interposing a standby interval between each scanning interval.