Abstract: An exemplary electromagnetic coupling device includes an electromagnet and a vane member that is selectively magnetically coupled with the electromagnet. A non-magnetic slider layer is supported on one of the electromagnet or the vane member such that the slider layer is between the electromagnet and the vane member. The slider layer maintains a spacing between the electromagnet and the vane member. In a disclosed example, the electromagnetic coupling device is used for coupling an elevator car door to a hoistway door for moving the doors in unison between open and closed positions.

Abstract: A smoke release and ventilation system comprises a frame housing upper and lower members each slidable in the frame between a normally closed position and an open position, the upper member being retained in its upper position by retaining element, for example an electromagnetic, the upper member being heavier than the lower member whereby, on release of the retaining, the upper member falls under gravity to its open position, and, consequential upon said fall of the upper member and the kinetic energy thereof, the lower member is raised to its open position, thereby providing gaps above and below the members and through which smoke can escape.

Abstract: The present invention is a bi-parting door system for transit vehicles. It has two doors mounted for movement in opposite directions and a motor for opening and closing them. It has at least one lock having a lock member for locking the doors in a closed position. The lock member is biased toward the locking position and moveable to an unlocking position by an actuator controlled by a control system which also controls the motor. When the doors are closed they experience a biasing force tending to open them and this biasing force is reacted by the lock member to generate a load on the lock member which prevents it from moving as a result of a spurious signal to the actuator. Unlocking of the doors requires a door closing signal to be received by the motor to remove the load from the lock member, as well as an unlocking signal to the actuator. Hence, the doors cannot be opened by any one spurious signal to either the motor or to the actuator.

Abstract: Controlled vertically swinging exit gates for milking parlor stalls having resilient control devices for lowering the gates in a smooth and controlled manner and to stop jerking downward or upward movement of the gate upon opening and closing, comprising two horizontally movable pulleys fastened to a draw-bar which actuates opposing cables to smoothly control operation of the gates.