Linear position sensor with anti-rotation device

• US 20100127697A1
• Filed: 11/20/2009
• Published: 05/27/2010
• Est. Priority Date: 11/26/2008
• Status: Active Grant

• Current Assignee: CTS Corporation
• Original Assignee: CTS Corporation
• Inventors: Storrie, William D., Newman, Robert L.
• Granted Patent: US 8,400,142 B2
• Time in Patent Office: Days
• US Class Current: 324/207.240
• CPC Class Codes: G01B 7/14 for measuring distance or clearance between spaced objects or spaced apertures G01B7/30 takes precedence
• CPC Class Codes: G01D 11/16 Elements for restraining, or preventing the movement of, parts, e.g. for zeroising caging of moving parts when not in use G01D11/20
• CPC Class Codes: G01D 11/245 Housings for sensors
• CPC Class Codes: G01D 3/028 mitigating undesired influences, e.g. temperature, pressure
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06

Abstract

An anti-rotation device or assembly for preventing the rotation of a magnet in a linear position sensor and eliminating the risk of undesired magnetic field measurements and incorrect sensor signal outputs. In one embodiment, the anti-rotation device is an anti-rotation plate which is fixed to the housing of the linear position sensor and a magnet carrier which includes at least one finger extending into a receptacle defined in either the edge or the body of the magnet carrier to prevent the magnet carrier from rotating relative to the plate. In another embodiment, the magnet carrier includes a key and the magnet includes a groove. The key extends into the groove for preventing the rotation of the magnet in the magnet carrier.

Claims

1. A linear position sensor comprising:

a housing;

a magnet carrier located in the housing, the magnet carrier including a base with a receptacle;

a magnet carried by the magnet carrier; and

a plate coupled to the housing and the magnet carrier, the plate including at least one finger extending into the receptacle in the base of the magnet carrier for preventing the rotation of the magnet carrier relative to the plate.

2. The linear position sensor of claim 1 wherein the base of the magnet carrier includes a peripheral edge, the receptacle being defined by a groove formed in the peripheral edge, and the finger on the plate is crimped around the peripheral edge and seated in the groove.

3. The linear position sensor of claim 1 wherein the base of the magnet carrier includes a lower surface and the finger on the plate abuts against the lower surface of the base of the magnet carrier.

4. The linear position sensor of claim 1 wherein the base of the magnet carrier includes a lower surface and the receptacle is defined by a slot formed in the lower surface, the finger on the plate extending into the slot.

5. The linear position sensor of claim 1 wherein the receptacle is defined by a through-hole extending through the base of the magnet carrier, the finger on the plate extending through the through-hole.

6. A linear position sensor comprising a magnet carrier including a magnet, the magnet carrier or the magnet including a key and the other of the magnet carrier or the magnet including a groove which receives the key for preventing the rotation of the magnet in the magnet carrier.

7. The linear position sensor of claim 6 wherein the key is a projection formed in an interior side surface of the magnet carrier and the groove is defined in an exterior side surface of the magnet.

8. The linear position sensor of claim 7 wherein the key is a projection formed in an interior bottom surface of the magnet carrier and the groove is defined in an exterior bottom surface of the magnet.

9. A linear position sensor comprising:

a housing;

a magnet carrier located in the housing;

a magnet located in the magnet carrier; and

anti-rotation means for preventing the rotation of the magnet.

10. The linear position sensor of claim 9 wherein the magnet carrier includes a base having at least one receptacle defined therein and the anti-rotation means comprises an anti-rotation plate coupled to the housing and the magnet carrier, the anti-rotation plate including at least one finger extending into the receptacle in the base of the magnet carrier to prevent the rotation of the magnet carrier.

11. The linear position sensor of claim 10 wherein the base of the magnet carrier includes a peripheral edge and the receptacle is defined by a groove formed in the peripheral edge.

12. The linear position sensor of claim 10 wherein the base of the magnet carrier includes a lower surface and the receptacle is defined by a groove formed in the lower surface of the magnet carrier.

13. The linear position sensor of claim 12 wherein the groove is a circumferentially extending slot formed in the lower surface of the magnet carrier.

14. The linear position sensor of claim 10 wherein the base of the magnet carrier includes opposed upper and lower surfaces and the receptacle is defined by a through-hole extending between the upper and lower surfaces of the magnet carrier.

15. The linear position sensor of claim 9 wherein the magnet carrier includes a magnet housing having an interior surface with a projection and the anti-rotation means comprises a groove in the magnet, the projection in the magnet carrier extending into the groove in the magnet to prevent the rotation of the magnet.

16. The linear position sensor of claim 15 wherein the projection is formed in an interior side surface of the magnet housing and the groove is defined in an exterior side surface of the magnet.

17. The linear position sensor of claim 15 wherein the projection is formed in an interior base surface of the magnet housing and the groove is defined in an exterior bottom surface of the magnet.

18. The linear position sensor of claim 17 wherein the magnet housing includes at least one prong extending from a peripheral top edge thereof and another groove is defined in an exterior top surface of the magnet, the prong extending into the groove in the exterior top surface of the magnet.

19. The linear position sensor of claim 9 wherein the magnet carrier includes a base having a lower surface and the anti-rotation means comprises an anti-rotation plate coupled to the housing and the magnet carrier, the anti-rotation plate including at least one interior slot formed therein defining at least one finger adapted to abut and exert a force against the lower surface of the base of the magnet carrier.