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:
Feb. 23, 1988
Filed:
Mar. 03, 1986
William R Foshee, Indianapolis, IN (US);
Best Lock Corporation, Indianapolis, IN (US);
Abstract
A door latch bolt spring-biased to projected position and retracted by a lever or other unbalanced handle is provided with a blocker plate loosely mounted on the rear face of the bolt and held in nonblocking position by a fusible pin or other heat-sensitive element. In case of fire, when elevated temperature may weaken the biasing spring and allow the unbalanced handle to exert retracting force on the latch, the heat-sensitive element releases the blocker plate and allows it to drop to an operative position where it will move against a stop to block retraction of the bolt. The plate is movable in either direction on the bolt so as to be operative on either hand or door. The tailpiece of the latch bolt carries means for mounting a reaction plate for the biasing spring and the blocker plate is loosely received between such plate and the rear face of the latch bolt. The reaction plate can be omitted when the blocker is not used, but can be supplied at any stage of manufacture or in the field when desired.