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:
Aug. 02, 1983
Filed:
Oct. 01, 1980
Matsushita Electric Works, Ltd., Osaka, JP;
Abstract
An ionization type smoke sensing device includes a printed board. An inner electrode made of heat-resistant metal is attached to the printed board and a radioactive source is fixed to the inner electrode. An outer electrode in the form of a bottomed cylinder made of heat-resistant metal and adapted to cover the inner electrode extends through the printed board and is integrally joined to a protective lid member made of heat-resistant metal at the back of the printed board. Therefore, the outer electrode and the lid member cooperate with each other to define an ionization chamber. The outer electrode is formed with smoke inlet ports for introducing smoke into the ionization chamber. The electric circuit serves to give pulse signals of a relatively high voltage to the outer electrode and to detect the presence of smoke on the basis of the amount of a current flowing through the inner electrode.