Abstract: A system for monitoring an elevator door in a hoistway. The elevator door is movable between a closed position and an open position. The system includes a transmitter for emitting an optical signal and an interlock device for latching the elevator door. The interlock device includes an optical nosepiece so positioned for receiving, guiding, and outputting the optical signal from the transmitter when the elevator door is closed and the interlock device is in the latched state. A receiver receives the optical signal via the nosepiece only when the elevator door is closed and the interlock is latched to thereby indicate the elevator door is in its latched state.

Abstract: A hydraulic elevator system 10 having an elevator car 12 in which car velocity V and car position L are determined by detecting the quantity Q of hydraulic fluid transferred between a hydraulic cylinder and a hydraulic fluid reservoir. The car velocity V is directly proportional to Q and the car position L is directly proportional to the integral of Q. The car velocity V, or quantity Q, is compared with a desired velocity pattern, or desired flow rate pattern, PG, and the difference is a control signal C which is used to control the quantity Q. The car position L may also be used to determine the distance-to-go to a target floor, which may be used to initiate slowdown and/or to calculate all, or selected portions of, the desired pattern PG.