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:
Jul. 25, 1989
Filed:
Jul. 21, 1988
John T Luebke, Kennewick, WA (US);
Sandvik Special Metals, Kennewick, WA (US);
Abstract
An apparatus for use in measuring the straightness of a tube includes a flat support surface made of electrically insulative material and a plurality of strips of electrically conductive material oriented parallel to one another on the support surface. The strips are substantially uniform in shape and thickness, and a layer of dielectric material covers each of the strips of conductive material. The layers of dielectric material are of uniform thickness along the length of the strips and are adapted to support a tube to be tested for straightness so that a capacitor is formed by each of the strips and the tube. An oscillators is provided for generating pulses each having a pulse width proportional to the capacitance between at least one of the strips and the tube and representative of the size of gap between the at least one strip and the tube. These pulse widths are measured and compared with a preset value representative of a limit pulse width in order to determine the acceptability of the tube straightness. A method of measuring the straightness of a tube by measuring capacitances along the length of the tube as it rolls along a support surface is also disclosed.