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:
Jan. 19, 1993
Filed:
Nov. 18, 1991
Robert F Lense, Rockford, IL (US);
Amerock Corporation, Rockford, IL (US);
Abstract
The sash of a roof window is swung between closed and open positions in response to the extension and retraction of a pair of pivotally supported crossed arms which are adapted to be swung by an operating mechanism whose mechanical advantage increases as the sash moves from its closed position to its open position. The increasing mechanical advantage of the operating mechanism offsets the decreasing opening force exerted by counterbalance springs during opening of the sash and enables the sash to be opened through its entire range with relatively constant manual effort. The initial preload in the counterbalance springs may be selectively adjusted to compensate for the weight of a particular sash and the pitch of a particular roof.