The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 19, 1991
Filed:
Feb. 02, 1990
Dietrich Jentsch, Ennepetal, DE;
Dorma GmbH & Co. KG, Ennepetal, DE;
Abstract
A door closer wherein a housing defines a fluid-containing space for a reciprocable damping piston which divides the space into a first and a second compartment. The piston carries a check valve which is closed during movement of the piston in a first direction while the door panel is being opened and which is open when the piston moves in the opposite direction. A channel is provided in the housing to permit fluid to flow from the first compartment into the second compartment during a first stage of movement of the piston in the first direction. The check valve has a body which defines a passage for the flow of fluid between the compartments and is surrounded by a seat having one or more grooves which are only partially overlapped by a spherical or non-spherical valving element during movement of the piston in the first direction to thus establish a relatively small path for the flow of fluid between the compartments, at least during a second stage of movement of the piston in the first direction, such second stage following the first stage. Springs in that compartment from which fluid is expelled during movement of the piston in the first direction oppose such movement of the piston, and an additional spring can be provided to bias the valving element against its seat.