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:
Mar. 12, 1996
Filed:
Nov. 03, 1993
Applicant:
Inventors:
Mai X Tu, Biel-Bienne, CH;
Michel Schwab, Biel-Bienne, CH;
Assignee:
Detra SA, Bienne, CH;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01B / ; G01V / ; H03K / ;
U.S. Cl.
CPC ...
32420716 ; 32420726 ; 324239 ; 324329 ; 324336 ;
Abstract
An inductive proximity sensor determines if a metallic object is in close proximity. An inductor is placed near the object. Several switches control the direction of the voltage passing through the inductor. During a first time period, the voltage flows through the inductor to induce a magnetic field in the object. During the second time period, the voltage is reversed in the inductor to quickly eliminate any current in the inductor. The decaying magnetic field in the object induces a voltage in the inductor which is measured during a third time period and compared to a reference value to determine the proximity of the object to the sensor.