Apparatus and method for increasing the efficiency of a door closer by reducing friction therein

摘要

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.