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:
Mar. 13, 1979
Filed:
Nov. 29, 1977
William F Doherty, Halifax, MA (US);
Chloride Incorporated, Tampa, FL (US);
Abstract
A smoke detector of the photo-electric type having a photo-responsive device viewing a volume illuminated by a light beam, in which a test member is provided for being temporarily positioned in the light beam so that one side of said member is exposed to the light and the other side is in the view of the photo-responsive device. The test member has an area near the forward edge which is thin in relation to the thickness of the rest of the test member. In one embodiment of the invention this area is thin enough to be translucent, so that the translucent area illuminated by the beam simulates a predetermined percentage of smoke in the beam with a high degree of accuracy, since the transmission characteristics of the translucent area can be consistently maintained within production tolerances, and the exact position of the translucent area in the light beam for the smoke simulation is not critical. In another embodiment of the invention, the thin area may or may not be translucent, and a small hole is provided therein extending completely through the thin area to pass a predetermined amount of light from one side of the thin area to the other.