Abstract: A control for a power-assist feature for an hydraulic closer is driven by structure mounted on the pinion shaft of the closer. It includes a pump-activating arm slidably mounted on the shaft, the end of the arm adapted to cover a pump-on sensor when the door is `bumped`. It also includes a follower rotatably mounted near the pinion and engageable escapement-fashion by a wheel in friction fit on the pinion shaft, the follower carrying a pump-deactivating arm, the end of the latter arm adapted to move away from a pump-off sensor when the door opens to its preset limit.

Abstract: An hydraulic door closer has a motor/pump component to assist opening the door by supplying oil under pressure to the closer cylinder. The component is activated by a switch sensitive to the turning of the closer pinion shaft as the door is moved out of its frame. Further, the distance which the door must move until the switch activates the motor/pump component is adjustable. The hydraulic circuitry is conveniently embodied in a single manifold block.

Abstract: An improvement in ball-type check valve arrangements including a valve body in which is formed a fluid passageway and a valve chamber communicating through a valve seat in the chamber, a ball in the chamber seated in the valve seat, and a reciprocal retaining member having a head engaging the ball in opposition to the valve seat and a stem extending from the head through the chamber wall opposite the valve seat, the ball and retaining member being reciprocably movable toward and away from the seat.