PATENT OF THE WEEK – AUTOMATIC DOOR CLOSER

The invention AUTOMATIC DOOR CLOSER was invented by Horst Tillmann (Ennepetal) on 15^th of March 1983, bearing patent number US4376323A.

The present invention relates to an automatic door closer with a closer shaft adapted to be connected to a door, and in which the closer shaft is turnably mounted in the region of the one end of an elongated housing in opposite directions from a position in which the door is closed.

In this invention a cam disk is fixed to the closer shafts cooperates over rollers carried by a slide to move the latter and a piston rod fixed thereto during opening movement of the door in a first direction. The slide is connected to a piston of a hydraulic damping arrangement and a spring arrangement forming an energy storage. The piston hence divides the interior of the housing into two pressure spaces which are connected to each other by channels for the throttled flow of the pressure medium from one pressure space, the volume of which is reduced during closing of the door, into the other pressure space.