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:
May. 13, 1980
Filed:
May. 19, 1978
Yukio Yamauchi, Kawasaki, JP;
Hiroshi Homma, Tokyo, JP;
Hochiki Corporation, Tokyo, JP;
Abstract
A smoke detector includes a light-emitting circuit, a light-receiving circuit, a smoke detecting space between the light-emitting and receiving circuits, and an amplifier circuit connected to the light-receiving circuit amplifying the output of the light-receiving circuit at an output terminal. An output comparison circuit is provided having an input terminal connected to the output terminal of the amplifier circuit and a voltage memory circuit is connected to another input terminal of the output comparison circuit. A detector circuit has one input terminal connected to the memory circuit and another input terminal connected to the output terminal of the comparison circuit, and a fire alarm circuit is connected to the detector circuit for operating an alarm when smoke from a fire fills such space between the light-emitting and receiving circuits, whereby contamination due to time and environmental factors has a minimal adverse effect on the detection of smoke in such space.