Cantilever beam G-switch

• US 5,092,172 A
• Filed: 06/20/1990
• Issued: 03/03/1992
• Est. Priority Date: 06/20/1990
• Status: Expired due to Fees

• Current Assignee: United States Of America As Represented By The Secretary Of The Army (Government of the United States of America)
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Overman, David L., Granfors, Roland A.
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/544,299
• Time in Patent Office: 622 Days
• Field of Search: 73/514, 73/517 AV, 73/492, 73/61.49, 73/488, 73/510, 340/669, 340/467, 200/61.45 R, 200/61.49
• US Class Current: 73/514.01
• CPC Class Codes: G01P 15/135 by making use of contacts which are actuated by a movable inertial mass
• CPC Class Codes: H01H 1/0036 Switches making use of microelectromechanical systems [MEMS] for electromagnetic relays H01H50/005; for electrostatic relays H01H59/0009
• CPC Class Codes: H01H 35/14 Switches operated by change of acceleration, e.g. by shock or vibration, inertia switch wherein the liquid constitutes a contact of the switch H01H29/002

Abstract

A sensing device for sensing acceleration consisting of a number of miniae steel bearing balls as mass elements, a housing for locating and containing the mass elements, a printed circuit board for sensing a discrete number of levels of acceleration, and an array of cantilever beam flexure elements equal in number to that of the mass elements located between the mass elements and the printed circuit board.

Claims

1. A layered electromechanical switch for sensing one or more discrete levels of acceleration, said switch comprising:

one or more mass elements;

a housing layer containing one or more blind holes, wherein each hole is shaped to accept a single mass element and to limit translation of said mass element in all directions except into and out of said hole, whereby each mass element will be located and contained within a corresponding blind hole when at rest;

a spring plate layer comprising one or more flexure elements, wherein each flexure element has both a fixed end and a free end, said free end being located a discrete distance from the fixed end and beneath a corresponding mass element which is not fixedly attached to said flexure element, whereby each flexure element will deflect a predetermined distance for a given level of acceleration;

a sensing means layer to detect contact with said flexure element or flexure elements upon deflection;

a spacer layer disposed between said spring plate layer and said sensing means layer.

2. The invention of claim 1 wherein each mass element is comprised of steel.

3. The invention of claim 1 wherein said mass element or elements are spherical.

4. The invention of claim 3 wherein each blind hole has a depth which is slightly less than the diameter of a corresponding mass element, whereby each mass element will protrude from a corresponding blind hole when at rest, thereby creating a prebias in the corresponding flexure element.

5. The invention of claim 1 wherein said sensing means layer comprises a printed circuit board, said circuit board provided with one or more conductive tracks, each track having a contact pad at the periphery of the sensing means layer and a contact pad located beneath the free end of a corresponding flexure element.

6. A layered electromechanical switch for sensing one or more discrete levels of acceleration, said switch comprising:

one or more spherical mass elements;

a housing layer containing one or more blind holes, wherein each hole has a depth which is slightly less than the diameter of a corresponding spherical mass element, whereby each mass element will protrude from and be located and contained within a corresponding blind hole when at rest;

a spring plate layer comprising one or more flexure elements, wherein each flexure element has both a fixed end and a free end, said free end being located a discrete distance from the fixed end and beneath a corresponding spherical mass element which is not fixedly attached to said flexure element, whereby each flexure element will be prebiased and sensitive to a predetermined level of acceleration in one direction;

a sensing means layer comprising a printed circuit board, said circuit board provided with one or more conductive tracks, each track having a contact pad at the periphery of the sensing means layer and a contact pad located beneath the free end of a corresponding flexure element;

a spacer layer disposed between said spring plate layer and said sensing means layer.

7. The invention of claim 6 wherein each spherical mass element is comprised of steel.