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:
Jul. 03, 1990
Filed:
Nov. 16, 1988
Dietrich Jentsch, Ennepetal, DE;
Dorma GmbH & Co. KG., Ennepetal, DE;
Abstract
A door closer wherein a housing defines a fluid-containing space and rotatably supports a shaft which is articulately connected with a pivotable door panel. A piston in the housing divides the space into a chamber and a compartment and has a toothed rack which mates with a pinion on the shaft so that the piston moves in the housing in response to rotation of the shaft as a result of pivoting of the door panel and vice versa. One or more springs in the chamber bias the piston in a direction to pivot the door panel toward closed position. A channel in the housing establishes communication between the chamber and the compartment during an initial stage of movement of the door panel from closed position at which time the piston moves in a direction to reduce the volume of the chamber. A bypass in the piston provides a path for the flow of fluid from the chamber into the compartment during a following stage of pivoting of the door panel toward open position, and the cross-sectional area of such path increases gradually in a direction from the chamber toward the compartment. The bypass can be provided in the peripheral surface of the piston or in the peripheral surface of the body of a check valve which is installed in the piston and serves to permit the fluid to flow from the compartment into the chamber during pivoting of the door panel toward closed position.