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:
Jun. 15, 1976
Filed:
Oct. 24, 1974
Yasaburo Adachi, Machida, JA;
Hiroaki Tsuru, Machida, JA;
Hochiki Corporation, Tokyo, JA;
Abstract
A fire alarm system having a plurality of ceiling fixtures containing ionization smoke detectors which are located in regions of a building to be protected. Each smoke detector is connected to a common fire alarm signal receiver for sounding an audible alarm as well as a visual alarm in response to a fire alarm signal therefrom. Each ionization smoke detector is also provided with an ionization ambient atmosphere auxiliary co-detector for producing an auxiliary signal which is responsive to the environmental conditions of the detector in situ. The ambient atmosphere detector comprises an internal circuit having female terminals of a receptacle mounted in the wall of the corresponding fixture, and an external circuit having male terminals of a plug adapted to mate with the corresponding female terminals of such receptacle. Such external circuit contains a visual signal indicating device as well as a recorder for tracing auxiliary signal patterns on a tape synchronized with the actual time of test of the ionization smoke detector being checked. Such patterns provide characteristic shapes corresponding to stable air, strong air current, feeble air current, dust, steam, static discharge, and cooking combustion products of the ambient atmosphere as distinguished from smoke due to fire, while the fire detector system per se is in actual use, and subject to possible false alarm caused by environmental conditions other than fire.