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:
Dec. 22, 1992
Filed:
Oct. 17, 1991
Gregory J Gerhard, Seattle, WA (US);
Kim W Atherton, Kirkland, WA (US);
Mitutoyo Corporation, Tokyo, JP;
Abstract
In a capacitive-type linear displacement measuring device, a pick-off body is resiliently biased into sliding contact with a scale. The pick-off body is supported by a flat spring and resiliently biased towards the scale by a leaf spring. The front surface of the scale slides in abutting contact with the front surface of the pick-off body. The flat spring restrains non-axial movement of the pick-off body but permits movement normal to the axial movement so that the pick-off body accurately tracks and remains in abutting contact with the scale as it slides in an axial direction. Changes in capacitance caused by axial displacement of the scale are accurately sensed and changes in capacitance caused by non-axial motion are avoided. According to an alternative embodiment, the pick-off body and scale are positioned with their sliding surfaces aligned with the axis of the support member to reduce the moment arm for any friction forces to zero, further reducing the likelihood of inaccurately sensing the axial movement of the scale.