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. 29, 1980
Filed:
Jan. 26, 1978
Robert B Enemark, Duxbury, MA (US);
Electro Signal Lab, Inc., Rockland, MA (US);
Abstract
A scatter type of smoke detector wholly supplied by a dry cell battery includes a clock circuit applying energy pulses to an LED light source which directs light pulses on a smoke sensing path. Light pulses scattered by smoke generate detection pulses in a photo diode whose amplitude is dependent on the smoke density. The clock pulses and detection pulses are applied to a control circuit including a dual, data-type flip-flop logic circuit and a threshold circuit driving an alarm horn. If the smoke density, and hence the detection pulse amplitude, exceeds a predetermined level the control circuit energizes the alarm in a continuous mode. If the battery drops below a preselected level the control circuit is actuated in an intermittent mode.