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.

Date of Patent:
Feb. 17, 1987

Filed:

Jul. 29, 1985
Applicant:
Inventors:

Fumio Kamiya, Nagaokakyo, JP;

Hisatoshi Nodera, Kusatsu, JP;

Kenji Ueda, Otsu, JP;

Keinosuke Imazu, Takatsuki, JP;

Hidehiro Tomioka, Kyoto, JP;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03B / ;
U.S. Cl.
CPC ...
331 65 ; 3311 / ; 331167 ; 324236 ;
Abstract

Disclosed is a proximity switch which includes a current feedback time oscillator so that an object in proximity may be detected from the decline in the oscillation output. In order to increase the recovery speed of the oscillation which has dropped as a result of detecting an approaching object, in addition to a first comparison circuit for detecting the object from the oscillation output level, a second comparison circuit is provided for varying the feedback current to the oscillation circuit to the end of maintaining the oscillation level at a certain low level even when the object has come sufficiently close to the proximity switch to otherwise completely terminate the oscillation. By virtue of the increased response speed of the proximity switch, it may be used in an environment where a strong AC magnetic field is present.


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