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:
Nov. 20, 1984
Filed:
Feb. 22, 1983
Horst Tillmann, Ennepetal, DE;
Dorma-Baubechlag GmbH & Co. KG, Ennepetal-Voerde, DE;
Abstract
An automatic door closer has an elongated fluid-filled housing having a closed end and an opposite open end, a plug closing the open end of the housing, a first piston reciprocatably arranged in the housing and dividing the latter into a first pressure space adjacent the closed end and a second pressure space adjacent the plug, a closer shaft adapted to be connected to a door, extending transverse to the elongation of the housing and turnably mounted in the housing in the region of the closed end, elements connecting said closer shaft with said first piston for moving the latter during turning of the closer shaft in door-opening direction in a first direction reducing the volume of the first pressure space while increasing the volume of the second pressure space, the piston-moving elements comprising a piston rod slidingly guided in the first piston and having a free end facing the plug, a spring cooperating with the first piston for biasing the latter in a second direction opposite to the first direction, a first throttled passage communicating at one end with the first pressure space and at the other end with a cylinder space formed in the first piston, a second throttled passage communicating at opposite ends respectively with the first and said second pressure space, a valve in the second throttled passage mavable between a closed position preventing flow of fluid through the second passage and an open position permitting flow of fluid through the second passage; and a second piston which is stationary and formed as a projection of the plug movably received in the cylinder space of the first piston.