TILT SWITCH EMPLOYING GRAPHITE

• US 20090223787A1
• Filed: 02/25/2009
• Published: 09/10/2009
• Est. Priority Date: 04/13/2005
• Status: Active Grant

• Current Assignee: Egresson LLC
• Original Assignee: Egresson LLC
• Inventors: Johnson, Michael David, Clark, Robert Louis JR.
• Granted Patent: US 7,934,321 B2
• Time in Patent Office: Days
• US Class Current: 200/61.520
• CPC Class Codes: H01H 35/02 Switches operated by change of position, inclination or orientation of the switch itself in relation to gravitational field tilting mercury container H01H29/20; change of position due to change of liquid level H01H35/18

Abstract

The invention relates to a form of a tilt switch that solves the problem of poor electrical contact, excessive/unpredictable hysteresis, high contact resistance, short life and/or electrical bounce. The tilt switch uses conventional ball-in-tube construction and adds a graphite powder film to all electrically conductive surfaces in the switch. This non-mercury tilt switch provides additional features such as enhanced electrical contact, reduced or eliminated hysteresis, lowered contact resistance, increased contact life and eliminates electrical bounce.

Claims

1. A self actuated tilt switch for reducing electrical hysteresis, comprising:

a casing enclosing a displacably mounted shorting member, said casing having an electrically conductive inner surface associated with a circuit;

said electrically conductive inner surface coated with a graphite film for reducing electrical hysteresis to below 1 degree (1°

), said graphite film acting as an insulator or conductor as a function of said graphite film'"'"'s thickness;

said casing sealed at one end by an insulating layer within a conductive shell, said conductive shell at least partially contacting said electrically conductive inner surface of said casing;

at least one electrode associated with said circuit inside of said casing;

said at least one electrode further comprising a terminal face for engaging said shorting member, said terminal face coated with a graphite film for reducing said electrical hysteresis;

said shorting member coated with a graphite film for reducing said electrical hysteresis; and

said shorting member for closing said circuit once reaching a predetermined threshold angle.

2. The self actuated tilt switch of claim 1, wherein said shorting member comprises a substantially spherical shorting member.

3. The self actuated tilt switch of claim 1, wherein said shorting member comprises a substantially cylindrical shorting member.

4. The self actuated tilt switch of claim 1, having two electrodes.

5. The self actuated tilt switch of claim 4, said two electrodes vertically displaced from each other.

6. The self actuated tilt switch of claim 4, said two electrodes horizontally displaced from each other.

7. The self actuated tilt switch of claim 1, wherein said terminal face comprises a conformal shape to said shorting member.

8. The self actuated tilt switch of claim 1, wherein said shorting member and said terminal face further comprise smoothly finished surfaces.

9. The self actuated tilt switch of claim 1, wherein said casing further comprises a recess for engaging said shorting member to open said circuit once reaching a predetermined threshold angle;

10. The self actuated tilt switch of claim 1 further comprising a passive angle indicating device, for visually indicating the reaching of said predetermined threshold angle.

11. A self actuated tilt switch, comprising:

a casing enclosing a displaceably mounted shorting member, said displaceably mounted shorting member coated with a graphite film for reducing electrical hysteresis;

said graphite film acting as an insulator or conductor as a function of said graphite film'"'"'s thickness;

a plurality of stationary electrodes inside said casing, said stationary electrodes coated with a graphite film for reducing operating hysteresis; and

said shorting member closing a circuit once reaching a predetermined threshold angle.

12. The self actuated tilt switch of claim 11, comprising two electrodes.

13. The self actuated tilt switch of claim 11, comprising three electrodes.

14. The self actuated tilt switch of claim 11, wherein said tilt switch further comprises an omni-directional tilt switch.

15. The self actuated tilt switch of claim 11, wherein said tilt switch further comprises a dual-angle tilt switch.

16. The self actuated tilt switch of claim 11, wherein said casing further comprises an electrically conductive casing.

17. The self actuated tilt switch of claim 11, further comprising a passive angle indicating device, for visually indicating the reaching of said predetermined threshold angle.

18. The self actuated tilt switch of claim 11, wherein said casing further comprises a recess for engaging said shorting member, said recess operable to engage said shorting member once reaching a predetermined threshold angle.

19. A method for indicating the reaching of a predetermined threshold angle, comprising the steps of:

measuring an angle by using an electrically conductive shorting member coated with a graphite film, said graphite film acting as an insulator or a conductor as a function of said graphite film'"'"'s thickness;

contacting said shorting member to two electrically conductive surfaces coated with a graphite film once said predetermined threshold angle is reached;

activating a circuit once said shorting member contacts said two electrically conductive surfaces;

removing said shorting member from the contact of at least one of said two electrically conductive surface once said pre-determined threshold angle is no longer reached;

de-activating said circuit once said shorting member leaves contact with at least one of said two electrically conductive surfaces; and

reducing operating hysteresis by coating said shorting member and said electrically conductive surfaces with a graphite film;

20. The method of claim 19 further comprising the step of visually indicating the reaching of said predetermined threshold angle via a passive indicating device.