OSCILLATOR PROXIMITY DETECTOR WITH REMOVABLE INTERCHANGEABLE SENSING HEADS

• US 3,719,898 A
• Filed: 01/22/1971
• Issued: 03/06/1973
• Est. Priority Date: 03/05/1970
• Status: Expired due to Term

• Current Assignee: Geoffrey Clarke
• Original Assignee: Geoffrey Clarke
• Inventors: Clarke, Geoffrey
• Primary Examiner(s): Lake, Roy
• Assistant Examiner(s): Grimm, Siegfried H.
• Application Number:
  US05/108,915
• Time in Patent Office: 774 Days
• Field of Search: 331/65,66 324/40,41 336/90,212 340/258C
• US Class Current: 331/65
• CPC Class Codes: G01V 3/101 by measuring the impedance of the search coil; by measuring features of a resonant circuit comprising the search coil measuring impedance or characteristics derived therefrom G01R27/00, e.g. quality factor G01R27/26
• CPC Class Codes: H03K 17/9505 Constructional details
• CPC Class Codes: H03K 17/9522 with a galvanically isolated probe
• CPC Class Codes: H03K 17/954 controlled by an oscillatory signal

Abstract

An electric proximity detector or switch for detecting the presence or absence of electrically conductive objects is provided with interchangeable sensing heads arranged to be removably mounted on a basic switch unit or to be positioned at a location remote from the basic switch unit as desired.

Claims

1. An electrical proximity switch comprising an enclosed switch Unit including a first sensing coil sensitive to electrically conductive objects proximate thereto and means responsive to changes in the electrical condition of the first sensing coil to provide an output signal, the first sensing coil being wound on a magnetizable core, a coupling member including an enclosure having disposed therein a coupling coil wound on a magnetizable core, means for removably mounting the coupling member on the switch unit with the coupling coil in inductive relationship with the first sensing coil, a sensing head including an enclosure having disposed therein a second sensing coil sensitive to electrically conductive objects proximate thereto and wound on a magnetizable core, and means for removably mounting the sensing head on the enclosure of the coupling member selectively in more than one position with respect thereto with the second sensing coil connected in a loop circuit with the coupling coil, whereby a change in the electrical condition of the second sensing coil causes a change in the electrical condition of the first sensing coil.

2. A proximity switch in accordance with claim 1 wherein said means for removably mounting the sensing head on the enclosure of the coupling member selectively in more than one position with respect thereto comprises a pair of intersecting threaded openings in said enclosure of the coupling member, prong means on said sensing head for insertion selectively into said openings, and fastening means threadably insertable selectively into said openings, the fastening means being threadably inserted into one of said openings to engage said prong means when the prong means is inserted into the other of said openings.

3. A proximity switch in accordance with claim 1 including a relatively large sensing head, a relatively small sensing head, and means for selectively and interchangeably mounting said sensing heads on said enclosure of the coupling member.