Abstract: An elevator car door is moved by a variable voltage, variable frequency linear induction motor which is driven open current loop to achieve a desired velocity profile indicated by an incremental linear encoder, with washed out proportional and integral gain. A magnetizing current insufficient to overcome the weight of the door is added in quadrature with the linear force current, and frequency is determined open loop in a predetermined fashion. Pulse width modulation voltage control signals are utilized to apply fixed voltages of correct polarity through a low pass three phase filter to the windings of the motor for correct intervals of time so as to synthesize desired sinusoidal winding currents. A boost of current is provided following each zero crossing of the sinusoidal winding currents to overcome lags therein. A ramp down of voltage avoids dropping the door at the end of door opening and door closing.

Abstract: An elevator car door is moved by a variable voltage, variable frequency linear induction motor which is driven open current loop to achieve a desired velocity profile indicated by an incremental linear encoder, with washed out proportional and integral gain. A magnetizing current insufficient to overcome the weight of the door is added in quadrature with the linear force current, and frequency is determined open loop in a predetermined fashion. Pulse width modulation voltage control signals are utilized to apply fixed voltages of correct polarity through a low pass three phase filter to the windings of the motor for correct intervals of time so as to synthesize desired sinusoidal winding currents. A boost of current is provided following each zero crossing of the sinusoidal winding currents to overcome lags therein. A ramp down of voltage avoids dropping the door at the end of door opening and door closing.

Abstract: A reciprocating elevator cab door is mounted on a guide track assembly which is fixed to the cab. The cab door is provided with guide rollers which travel along the upper surface of the guide track as the door opens and closes. The door is also provided with at least one upthrust roller which engages the lower surface of the guide track so as to stabilize the door against rocking motion as it moves back and forth over the guide track. The upthrust roller is preferably spring biased against the guide track. Use of the upthrust roller allows greater flexibility of door drive systems.

Abstract: A magnetic coupling device is disposed on an elevator car door in a position to engage a magnetic vane disposed on a hoistway door which is to be opened in unison with the car door. The magnetic coupling unit may comprise either an electromagnet or a permanent magnet and has spring loaded rollers disposed above and below it so as to control the initial force of engagement between the elevator car door and the hoistway door, for smoother door opening operation.

Abstract: A horizontally stiff, but vertically yielding coupling between an elevator car door and an elevator hoistway door includes a brushless torque actuator which rotates a member (disposed on the elevator door) between a first, clearance position and a second, coupling position where it becomes wedged between the walls of a channel disposed on a hoistway door. The member may have rollers to make contact with the walls of the channel, or it may simply have sliding surfaces for contact with the channel.

Abstract: An elevator hoistway door lock comprises a rod journaled for rotation on a hoistway door. A pin which extends laterally from the rod engages a lip when the rod is rotated into a locked position by means of its own weight, and optionally a spring. The pin clears the lip when the rod is rotated into an unlocked position by means of a retiring cam disposed on the elevator car. The electrical safety switch contacts are interconnected by a rotating contact disposed on the rod, only when the rod is rotated to place the pin in the locked position.

Abstract: An elevator hoistway door is coupled to an elevator car door so as to be opened and closed in unison therewith by means of a pair of shoes which are mounted on the elevator door and have cammed surfaces that allow the shoes to be spread so as to be wedged within the walls of a channel that is mounted on the hoistway door. The wedging action is caused by a solenoid actuator and the shoes are returned by means of a spring to a rest position in which they have adequate clearance within channels of all of the hoistway doors which the elevator may pass. Advance door opening and releveling is accommodated by means of rollers or sliding contact.

Abstract: A linear motor is used to actuate an elevator door in response to a control signal for counteracting rotational torque caused by a variable-length moment arm about the center of gravity of the door by varying the magnitude of a linear force exerted on the door acting through a fixed-length moment arm about the center of gravity of the door for providing an opposing rotational torque, thereby counteracting the rotational torque caused by the normal force. The first and second rotational torques may be controlled to decrease and increase linearly as the door goes through its motion. In this way, the velocity profile varies in a curve similar to one side of the major axis of an ellipse. The normal force may be provided so as to levitate the door to reduce gravitational forces acting on door rollers. The control may be carried out in an open- or closed-loop fashion.

Abstract: A gasoline station with self-service and attendant operated pumps and a fuel delivery control and registration system with a fixed remote control unit operable for selectively activating each self-service pump and registering the amount of fuel delivered and a portable control unit for operating the fixed control unit and registering the amount of fuel delivered via two-way radio communication between the portable and fixed control units.