Force transducer having a central portion of reduced thickness

• US 6,807,872 B2
• Filed: 08/14/2002
• Issued: 10/26/2004
• Est. Priority Date: 02/22/2000
• Status: Active Grant

• Current Assignee: Office National D'Etudes et de Recherches Aerospatiales
• Original Assignee: Office National D'Etudes et de Recherches Aerospatiales
• Inventors: Muller, Serge, Lecorre, Bernard, Le Traon, Olivier, Janiaud, Denis
• Primary Examiner(s): NOORI, MAX H
• Application Number:
  US10/217,516
• Publication Number:
  US 20030000317A1
• Time in Patent Office: 804 Days
• Field of Search: 738/626.27, 738/626.29, 738/626.32, 738/626.36, 738/626.37, 73/73, 738/56, 738/625.9, 738/626.1, 738/626.21
• US Class Current: 73/862.632
• CPC Class Codes: G01L 1/106 Constructional details

Abstract

The invention concerns a transducer constituting the sensitive member of a sensor whose frequency varies as a function of the intensity of force applied to it. The force transducer comprises a beam having length and rectangular cross-section with thickness and width and flexionally vibrating. The beam has a thickness reduced over a central portion of its length, its width remaining constant.

Claims

1. A force transducer comprising a beam adapted for flexional vibration and having longitudinally-extending orthogonally-arranged sensitivity (PS) and vibration (PV) planes of symmetry, respectively, said beam having a rectangular cross-section and including a pair of end portions, and a central portion contained between said end portions, said beam having a width dimension (1) extending in said plane of sensitivity that is constant, said beam having a thickness dimension extending in said plane of vibration that is less in said central portion (e2) than in said end portions (e1).

2. A force transducer according to claim 1, wherein said beam thickness in the middle of said beam length lies between one third and two thirds the greatest thickness at ends of said beam.

3. A force transducer according to claim 1, wherein said beam comprises an odd integer number of parallelepiped-shaped disposed along along said beam length, said portions having thickness decrease from end portions of said beam toward said central portion.

4. A force transducer according to claim 3, wherein said end portions are substantially identical, and said central portion has a length which lies between half and twice the length of each of said end portions.

5. A force transducer according to claim 4, wherein the thickness of said central portion is substantially half the thickness of said end portions, and said central portion and said end portions have substantially equal lengths.

6. A force transducer according to claim 1, wherein the thickness of said beam decreases progressively from each end of said beam toward the center of said beam.

7. A force transducer according to claim 1, comprising means including electrodes disposed in the vicinity of ends of said beam for imparting flexional vibration to said beam.

8. A force transducer according to claim 7, wherein said electrodes are connected by electrical connection tracks disposed on said central portion of said beam.