Door holder-closer having a control signal operated hold-open function and a mechanical override facility

摘要

A door closing apparatus is described which embraces a unit for generating a closing force, a lever attached thereto via a releasable clutch for actuating the door and a controllable blocking device. The releasable clutch consists of a threaded connection which permits relative rotation between the actuating lever and the drive axle over a predetermined stroke. An abutment for frictionally locking the actuating lever is provided, with the frictional locking abutment becoming effective relative to the actuating lever at at least one end of the stroke. The holding force which sets in between the actuating lever and the frictional locking abutment is smaller than the holding force of the blocking device which blocks the unit for generating the closing force in the closing direction.