Vibrating string resonator

• US 4,710,668 A
• Filed: 12/02/1985
• Issued: 12/01/1987
• Est. Priority Date: 12/04/1984
• Status: Expired due to Term

• Current Assignee: Office National D'Etudes et de Recherches Aerospatiales, Crouzet (Schneider Electric SE)
• Original Assignee: Office National D'Etudes et de Recherches Aerospatiales, Crouzet (Schneider Electric SE)
• Inventors: Janiaud, Denis, Fima, Henri
• Primary Examiner(s): BUDD, MARK OSBORNE
• Application Number:
  US06/803,160
• Time in Patent Office: 729 Days
• Field of Search: 310/321, 310/323, 310/324, 310/338, 310/367, 310/368, 310/361, 310/25, 310/330-332, 73/777, 73/778, 73/781, 73/141 R, 73/DIG. 1, 73/DIG. 4, 357/26, 338/2, 338/47
• US Class Current: 310/323.21
• CPC Class Codes: G01L 1/106 Constructional details
• CPC Class Codes: G01L 1/162 using piezoelectric resonators
• CPC Class Codes: H03H 9/17 having a single resonator crystal tuning forks H03H9/21

Abstract

The invention provides a string resonator vibrating under flexion whose oscillation is maintained by piezoelectric, electrostatic or magnetic exitation means.

Decoupling is obtained by inertia masses which oscillate in the vibration plane of the string, between the string and fixing supports, with a movement of rotation about an axis orthogonal to the vibration plane of the string and at the level of flexible elements. The resonator is easy to manufacture, inexpensive and hase a good coefficient of quality. It may be used for force, pressure sensors or gyroscopes.

Claims

1. A resonator, comprising:

a beam capable of vibrating under flexion;

a pair of fixing means for fixing said beam at both of its ends;

a pair of inertia mass means disposed between said beam and respective ones of said fixing means for providing a vibratory decoupling between said beam and said pair of fixing means;

a pair of flexible articulation means disposed between and interconnecting respective ones of said inertia mass means and said fixing means;

a pair of flexible articulation means disposed between and interconnecting respective ones of said inertia mass means and said fixing means;

each inertia mass means being mounted to oscillate in a vibration plane in which said beam vibrates and to pivot about a pivot axis orthogonal to said vibration plane, said pivot axis being situated at one of said flexible articulation means;

each inertia mass being rigid, compact and having a convex contor and being connected at its face opposite to said beam to one of said flexible articulation means;

each inertia mass means being driven to rotate only about said pivot axis in response to vibration of said beam; and

the pair of inertia mass means having predetermined sizes to yield in said vibration plane a substantially zero resulting force applied to said pair of fixing means by said beam, said pair of inertia mass means and said pair of flexible articulation means.

3. The resonator as claimed in one of claims 1 or 2, wherein said inertia mass comprises at least two elementary masses connected together by a flexible element allowing rotation of each elementary mass in the vibration plane of said string.

4. The resonator as claimed in one of claims 1 or 2, wherein the natural resonance frequency of said inertia masses is higher than that of said vibrating string.

5. The resonator as claimed in one of claims 1 or 2, wherein said string is adapted for vibrating in a fundamental flexion mode.

6. The resonator as claimed in one of claims 1 or 2, wherein said string is adapted for vibrating in a partial flexion mode.

7. The resonator as claimed in one of claims 1 or 2, wherein, in the vibration plane of the string, said inertia masses have the form of a rectangle.

8. The resonator as claimed in one of claims 1 or 2, wherein, in the vibration plane of the string, said inertia masses have the form of an ellipse.

9. The resonator as claimed in one of claims 1 or 2, having a one piece structure and being cut out from a slab of material of uniform thickness.

10. The resonator as claimed in claim 9, wherein the material of uniform thickness is a quartz string kept on one of its resonance frequencies by piezoelectric effect.

11. The resonator as claimed in claim 10, obtained by ultrasonic machining in a single operation using a single tool.

2. A resonator, comprising:

a beam capable of vibrating under flexion and having one free end;

a fixing means for fixing said beam at its other end;

an inertia mass disposed between said fixing means and said beam for providing a vibratory decoupling between said beam and said fixing means;

a flexible articulation means disposed between and interconnecting said inertia mass and said fixing means;

said inertia mass being mounted to oscillate in a vibration plane of said beam and to pivot about a pivot axis orthogonal to said vibration plane, said pivot axis being situated at the flexible articulation means;

said inertia mass being rigid, compact and having a convex contour and being connected at its face opposite to said beam to said flexible articulation means;

said inertia mass being driven to pivot only about said pivot axis in response to vibration of said beam; and

said inertia mass having a predetermined size to yield in said vibration plane a substantially zero resulting force applied to said fixing means by said beam, said inertia mass and said flexible articulation means.