Non-prismal beam resonator

• US 4,445,065 A
• Filed: 09/14/1981
• Issued: 04/24/1984
• Est. Priority Date: 09/14/1981
• Status: Expired due to Term

• Current Assignee: Kearfott Guidance and Navigation Corporation
• Original Assignee: Singer PLC (Hayleys Plc)
• Inventors: Albert, William C.
• Primary Examiner(s): Wong, Peter S.
• Application Number:
  US06/301,623
• Time in Patent Office: 953 Days
• Field of Search: 310/321, 310/323, 310/330, 310/338, 310/348, 310/367, 310/368, 310/370, 310/15, 310/25, 73/777, 73/778, 73/781, 73/DIG. 1, 73/DIG. 4
• US Class Current: 310/321
• CPC Class Codes: G01L 1/162 using piezoelectric resonators

Abstract

A single beam force transducer has a beam characterized by a thickened central portion and tapered outward portions. The support members of the transducer are thickened and are thus stiffer while the isolator masses are shortened. These critical configuration changes raise the undesirable "tuning fork" resonant frequency of the beam supporting structure far above that of the beam and ensures that the isolating structure behaves as a rigid body.

Claims

1. In a force transducer, an isolator structure generally shaped like a tuning fork for supporting a beam having a longitudinal axis and adapted to vibrate in a plane including the axis, the isolator structure comprising:

a thickened support element secured to each end of the beam and extending in both directions transversely of said axis of the beam;

a pair of end mounts;

a pair of thin spaced isolator springs extending between each mount and a corresponding support element for transmitting axial forces from the end mounts to the beam along the axis thereof; and

a pair of cantilevered parallel spaced shortened isolator masses secured at first ends thereof to each support element;

wherein the isolator structure supporting the beam behaves as a rigid body and raises the "tuning fork" resonant frequency of the isolator structure far above the beam resonant frequency thereby preventing interference of the latter resonant frequency.

2. The structure set forth in claim 1 wherein the beam has a non-prismal configuration comprising a central portion which is thicker than the outward ends permitting the beam to bend easily thus reducing the bending moment.

3. The structure set forth in claim 1 wherein the beam has a central portion extending outwardly to thinner end portions, each of which has a rectangular cross section permitting the beam to bend easily thus reducing the bending moment.

4. The structure set forth in claim 1 wherein the beam has a relatively thick central portion gradually tapering at opposite ends thereof permitting the beam to bend easily thus reducing the bending moment.

5. A single beam force transducer comprising:

a beam isolating structure;

a non-prismal beam having a central portion extending outwardly to thinner end portions respectively connected to the isolating structure, the thinner end portions permitting the beam to bend easily thus reducing the bending moment.

6. The structure set forth in claim 5 wherein the beam has a rectangular cross section.

7. The structure set forth in claim 5 wherein the beam has a gradually tapering cross section.

8. The structure set forth in claim 5 wherein the isolating structure comprises:

a thickened support element secured to each end of the beam and extending in both directions transversely of said axis of the beam;

a pair of end mounts;

a pair of thin spaced isolator springs extending between each mount and a corresponding support element for transmitting axial forces from the end mounts to the beam along the axis thereof; and

a pair of cantilevered parallel spaced shortened isolator masses secured at first ends thereof to each support element;

wherein the isolator structure supporting the beam behaves as a rigid body and raises the "tuning fork" resonant frequency of the isolator structure far above the beam resonant frequency thereby preventing interference of the latter resonant frequency.