Magnetically actuated indicator

• US 4,128,825 A
• Filed: 12/13/1976
• Issued: 12/05/1978
• Est. Priority Date: 12/13/1976
• Status: Expired due to Term

• Current Assignee: North American Philips Corp. (Koninklijke Philips N.V.)
• Original Assignee: North American Philips Corp. (Koninklijke Philips N.V.)
• Inventors: Madsen, Elmer W.
• Primary Examiner(s): Broome, Harold
• Application Number:
  US05/750,008
• Time in Patent Office: 722 Days
• Field of Search: 335/272, 335/253, 340/373, 340/378, 40/28
• US Class Current: 335/272
• CPC Class Codes: H01F 7/08 with armatures
• CPC Class Codes: H01F 7/145 Rotary electromagnets with variable gap with fixed gap or torque motors H02K26/00

Abstract

A magnetically actuated indicator includes a housing carrying an elongated permanent magnet for pivotal motion about a geometric axis which extends transversely to the geometric axis of the magnet. First and second poles are carried by the housing and are disposed in spaced relationship to each other and each is proximate to one end of the elongated permanent magnet in one angular position thereof. A coil is magnetically linked to the poles to change the polarity thereof and a stop prevents positioning of either end of the permanent magnet intermediate the two poles to insure consistant indications.

Claims

1. An elongated permanent magnet having one north pole at a first end and a south pole at the second end;

means for pivoting said magnet about a geometric axis which extends transversly to the geometric axis of said elongated permanent magnet at a point intermediate said ends thereof, said means for pivoting allowing rotational travel of said magnet between a first angular position and a second angular position;

first and second poles carried by said housing and disposed in spaced relationship to each other, said first pole being proximate to said one end of said elongated magnet in said one angular position of said elongated permanent magnet and said second pole being proximate to said second end of said elongated permanent magnet in said second angular position of said elongated permanent magnet;

a coil cooperating with said first and second poles to vary the polarity thereof; and

interfering surfaces carried on said housing and said elongated permanent magnet to prevent angular movement of either end of said elongated permanent magnet past a point intermediate said first and second pole, said interfering surfaces being spaced from both said first and second poles.

2. The apparatus as described in claim 1 wherein said elongated permanent magnet is disposed in a member which is symmetrical about said geometric axis which said elongated permanent magnet pivots.

3. The apparatus as described in claim 2 wherein said member which is symmetrical is manufactured of a non-ferrous material.

4. The apparatus as described in claim 3 wherein said material is a plastic.

5. The apparatus as described in claim 3 wherein said member which is symmetrical is generally cylindrical.

6. The apparatus as described in claim 3 wherein said member which is symmetrical is generally spherical.

7. The apparatus as described in claim 4 wherein said member which is symmetrical has pivot surfaces extending from the member, said pivot surfaces being symmetrical about said axis or rotation of said elongated permanent magnet.

8. The apparatus as described in claim 7 wherein said interfering surfaces comprise a boss aligned generally with said axis of rotation of said member which is symmetrical and also at least one descrete stop member carried on said housing.

9. The apparatus as described in claim 8 where said housing has a planar surface extending around said member which is symmetrical.

10. The apparatus as described in claim 9 wherein said member which is symmetrical has two opposite sides thereof which are planar and parallel to each other, one of said planar sides being disposed in parallel flush relationship to said planar surface of said housing.

11. The apparatus as described in claim 1 further including a yoke and an arm extending therefrom, said yoke carrying said first and second poles and said coil is disposed around said arm.

12. The apparatus as described in claim 1 wherein said first and second poles are joined by a magnetically permeable member about which said coil is disposed.

13. The apparatus as described claim 1, wherein said interfering surfaces are disposed to interfere only when said elongated permanent magnet is disposed with one end intermediate said first and second poles.