Force sensors
First Claim
1. A beam structure for a vibrating beam force sensor of the type wherein a beam or strip of a piezoelectric material mounted at either end is piezoelectrically driven into flexural vibration while under stress, a change in the vibrational frequency indicating a change in the stressing force, wherein the structure comprises at least three coplanar beams, a common pair of mountings for these beams, and the beams are spaced side by side and supported between the common mountings one at either end of the beams for flexural vibration in a plane normal to the beams'"'"' common plane, and wherein the three coplanar beams generally are of the same length, but the breadth of each of the two outer beams is half that of the inner one, said beams in operation flexing in a direction normal to the plane of the beams, with the two outer beams flexing in opposite phase to the inner beam.
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Accused Products
Abstract
A piezoelectric beam structure for a vibrating beam force sensor in which three coplanar beams of piezoelectric material are spaced side by side and supported between respective common mountings at either end. The two outer counterbalancing beams in operation flex in opposite phase to the center main beam, with each beam flexing in a direction normal to the beam plane. A force sensor which includes this piezoelectric beam structure.
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Citations
13 Claims
- 1. A beam structure for a vibrating beam force sensor of the type wherein a beam or strip of a piezoelectric material mounted at either end is piezoelectrically driven into flexural vibration while under stress, a change in the vibrational frequency indicating a change in the stressing force, wherein the structure comprises at least three coplanar beams, a common pair of mountings for these beams, and the beams are spaced side by side and supported between the common mountings one at either end of the beams for flexural vibration in a plane normal to the beams'"'"' common plane, and wherein the three coplanar beams generally are of the same length, but the breadth of each of the two outer beams is half that of the inner one, said beams in operation flexing in a direction normal to the plane of the beams, with the two outer beams flexing in opposite phase to the inner beam.
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8. A piezoelectric beam structure for a vibrating beam force sensor comprising:
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a strip of piezoelectric material; a pair of substantially parallel, longitudinal slots in said strip forming three coplanar beams of piezoelectric material spaced side by side on said strip, said beams in operation flexing in a direction normal to the plane of the beams; and said three coplanar beams including a main beam between said slots and a respective counterbalancing beam on either side thereof, thereby defining three substantially parallel beams, wherein the mass of each counterbalancing beam is formed to be one-half the mass of the main beam. - View Dependent Claims (9, 10, 11, 12, 13)
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Specification