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:
Jun. 08, 1993
Filed:
Jun. 11, 1991
William J Bailey, Louisburg, KS (US);
Tomkins Industries, Inc., Dayton, OH (US);
Abstract
A fire damper comprising a plurality of interconnected blades is provided with a pair of primary negator type springs which are attached to the leading blade and a pair of auxiliary negator type springs which are attached to an intermediate blade. The blades are normally maintained in a folded condition with the springs exerting a biasing force urging movement of the blades to an extended closed position. Upon release of the blades in response to detection of fire or smoke conditions, the springs cooperate to move the blade assembly to the completely closed position. The auxiliary springs increase the rate of closing of the assembly and facilitate unfolding of a portion of the blade assembly to enhance the closing of the assembly even under high air flow conditions.