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. 20, 1981
Filed:
Jul. 25, 1979
John K McVey, Bensenville, IL (US);
Illinois Tool Works Inc., Chicago, IL (US);
Abstract
A temperature-responsive electrical switch is provided which has a pair of axial leads, one of which is connected to the cylindrically-shaped electrically conductive housing, and the other of which passes through an insulator into the interior of the housing. A cylindrical-shaped, slideable electrical contact which is open at one end is positioned in the housing. A coil spring is located inside the slideable contact between the bottom end of the contact and an enlarged section of the insulator. The contact has a plurality of spring fingers which are integrally formed from the bottom of the contact and which project upwardly from the bottom of the contact toward the head of the insulated lead. A thermally-sensitive pellet, which melts at a predetermined temperature and is formed to have a cavity in it, is positioned below the spring fingers. The pellet is dimensioned transversely so as to force the fingers into contact with the head of the insulated lead. Upon reaching the predetermined temperature the pellet melts and its liquid mass assumes a smaller transverse dimension, because of the original cavity in the solid pellet. This allows the spring to release its compressive force; and this, in turn, allows the slideable contact to move along the interior of the housing so as to thereby break electrical contact between the spring fingers and the head of the insulated lead.