Abstract: A door closer has a fluid conduit connecting the high pressure portion of the cylinder in front of the piston with a cavity between the surfaces of the cylinder wall and the piston. This cavity is located at the intermediate lateral surface of the piston at the back side of a gear rack formed on the piston. The variable lateral bias provided by the pressurized cavity counteracts separating forces between the gear rack and a gear pinion caused by the tapered teeth. This decreases friction between the piston and the cylinder and reduces wear throughout the closer mechanism.

Abstract: Disclosed is a door control device that automatically repositions the driving shaft of the door closer toward and away from the door pivot, as the door opens and closes, as a means of modifying and improving the force required to open and close the door. Movement is accomplished by a double ended driving shaft having a sprocket gear on one end which drivingly engages a track which in turn repositions the slide mounted door closer to more favorable positions as the door opens and closes.

Abstract: A door closer mechanism that controls the opening and closing swing of a door, in conjunction with an integral switch that electrically signals when the security of the closed door has been violated by partially opening the door. The device is especially important and useful in high security installations including detention facilities and features a secure field adjustment feature to accommodate door positioning and rattle.

Abstract: Disclosed is a tamper resistant assembly of a roller or slider in a track that can be used advantageously in schools, public buildings, detention facilities and the like; wherever the potential for vandalism and mischief is likely. In the present device the track is provided with unique sloped ends which expel, up and out, any foreign material placed in the track as it is moved along by the roller or slider toward the end of the track where it would ordinarily jam.

Abstract: A door position indicator for a door closer which senses the position of a door closer piston as a means of sensing door position. The door closer and hence the door position indicator may be recessed in the door jamb over the top edge of the door thereby providing additional security to the door position sensing device.

Abstract: A releasable door hold-open device or assembly is mounted on the header over a door panel. The assembly has a track channel with a top web and depending flanges. A door panel connector arm has a traveller movable in the track channel. A solenoid operates a detent in the track channel near the hinge end of the traveller path. A conductor channel is fastened to the top web and communicates with the track channel through an opening. A connector block releasably adjoins the track channel and the conductor channel at the hinge end thereof. A smoke detector underlies the connector channel at the other end of the track channel. Conductors from outside extend through the connector block, through connecting plugs in the block and track channel and to the solenoid and through the conductor channel to the smoke detector.

Abstract: A typical door closer has a cylinder in which a piston reciprocates to compress a spring. An assistor for such a closer has a cylindrical shell fastened to one end of and continuing the cylinder. The shell has a barrier wall at one end adjacent the cylinder, a partition wall dividing the shell into a booser compartment and a main compartment, and a head wall at the other end. Air under regulated pressure is supplied to the main compartment, wherein the air presses a main plunger tube, extending through the partition wall, against a booster plunger having a rod extending through the barrier wall and abutting the piston. A port in the plunger tube receives air from the main compartment through the tube. In some plunger tube positions the port is blocked by the partition wall and in other plunger tube positions opens into the first compartment. A check valve when open allows air flow from the booster compartment to the main compartment.

Abstract: An adjustable spring loading mechanism for use in controlling the movement of doors and the like. The mechanism includes a cylinder housing and a piston slideable within the housing. A plurality of biasing means are arranged in the housing in engagement with the piston, and apply individual biasing forces to the piston which cooperate to produce a total resultant biasing force. The biasing means are provided with different effective lengths so as to engage with the piston at different positions in the cylinder and thereby vary the total biasing force.