Automatic door closer constructed for releasably holding a door in a predetermined partly open position

摘要

An automatic door closer constructed for releasably holding a door in a predetermined partly open position mainly comprises a piston arranged in a cylinder bore of a housing and operatively connected to a closer shaft mounted in the housing turnable about an axis substantially normal to that of the cylindrical bore so that the piston will be reciprocated in the bore during turning of a door connected to the closer shaft. The piston divides the bore in the housing in two compartments filled with fluid and a coil compression spring in one of the compartments biases the piston to an end position corresponding to the closed position of the door. The piston is provided with two passages therethrough, in one of which a one-way valve is arranged permitting flow of fluid only from the one compartment into the other during movement of the piston in door opening direction. The other passage is closed when the door reaches a predetermined partly open position preventing thereby fluid flow from the other compartment into the one compartment so that the door is held in this partly open position. The elements for closing the other passage comprise a valve member of a holding valve biased by a spring to a closed position so that the door may be moved in closing direction from the partly open position in which it is held only by application of an outer force applied thereto overcoming the biasing force of the spring acting on the valve member.