Abstract: An apparatus and method for adding a velocity transducer to an electric motor, such as an elevator drive motor, includes mounting a shaft extension on an end surface of a motor shaft by drilling and tapping a bore at the shaft center as parallel as possible. A fastener with a bevel washer between a pair of flat washers attaches the extension to the motor shaft. With the fastener assembly snug, the extension is trued radially with a dial indicator. The bevel washer functions as a spring lock and distributes any off center clamping force produced from non-concentric hole drilling. A shoulder on the extension abuts the motor shaft end surface to maintain parallelism of the longitudinal axes of the shaft extension and the motor shaft. The shaft extension can be formed of an electrically nonconductive material to isolate the transducer from the drive equipment.

Abstract: An elevator system including an elevator car having an electromechanical door restraint mechanism which includes a locked position which permits slight opening of the door by passengers for ventilation purposes, while preventing the forcible opening of the elevator car door beyond that point when the elevator car stops outside a predetermined allowable displacement zone adjacent to a floor level. Power supply failure deenergizes a first solenoid of the mechanism which causes the door restraint mechanism to assume its locked position. A capacitor, charged by the power supply before failure thereof, energizes a second solenoid to unlock the door when the elevator car is within an allowable displacement zone, and the closed door is moved slightly by a passenger towards its open position. Continued movement of the car door, beyond the predetermined point, returns the mechanism to the locked position, which now prevents complete closure of the car door.