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:
Apr. 07, 1992
Filed:
May. 07, 1990
John Lahlouh, San Jose, CA (US);
Ray F Stewart, Redwood City, CA (US);
Robert S Wasley, San Carlos, CA (US);
Paul D Hauptly, Fremont, CA (US);
Laurence M Welsh, Palo Alto, CA (US);
Raychem Corporation, Menlo Park, CA (US);
Abstract
Devices for detecting and obtaining information about an event, for example the presence of a liquid, which comprise (1) a swellable member which swells upon occurrence of the event and (2) a restraining member which, when the swellable member swells, restricts movement of the swellable member and thus causes the impedance of the device to change. In a preferred embodiment the device comprises two elongate conductors helically wrapped around a support core, a swellable, conductive polymer member surrounding the conductors. Occurrence of an event causes the swellable material to swell and form a conductive bridge between the conductors.