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. 06, 1996
Filed:
Jan. 24, 1994
Shih-Ying Lee, Lincoln, MA (US);
Setra Systems, Inc., Acton, MA (US);
Abstract
A variable capacitance type pressure sensor with excellent manufacturability center-mounts an electrode on an edge-mounted diaphragm using a metal-glass-metal subassembly. An inner metal post of the assembly is welded to the diaphragm. A solder or flowable cement secures the electrode to an outer metal collar of the assembly with the initial diaphragm-to-electrode spacing set by a temporary shim. The position of the glass and the physical lengths of the metallic members of the assembly are adjusted to provide self-compensation for temperature variations. In a preferred form for low and medium pressure applications, the diaphragm is stamped from sheet metal with a central dimple that resists rotation of the attached assembly and isolates diaphragm deformation stresses from the post-to-diaphragm weld. In a high pressure form, a machined central boss isolates this weld from stress. A fitting that edge-mounts the diaphragm has a thinned end wall, or the diaphragm has a thin-walled skirt, to relieve stress on the diaphragm-to-fitting joint.