Pendular non-servoed tuning beam accelerometer
First Claim
1. Pendular accelerometer comprising a base, a pendular seismic mass of flat shape connected to the base by a flexure hinged connection for pivotal movement of said seismic mass about a hinge axis perpendicular to major surfaces of said pendular seismic mass, along a sense direction perpendicular to the hinge axis of the hinged connection and sensor means connecting the seismic mass to the base, wherein said sensor means comprises:
- at least two vibrating beams of piezo-electric material, each connected to the base at an end thereof and to the seismic mass at the other end thereof, and each provided with electrode means for vibrating the respective beam at a tuning frequency thereof, said beams being directed orthogonally to the same axis and being located symmetrically with respect to the seismic mass on both sides of the hinge axis of the hinged connection, whereby any acceleration along the sense axis creates tractive stresses in one beam and compression stresses in the other beam, andcircuit means connected to the electrodes and arranged for delivering a signal which is responsive to the difference between the resonant frequencies of the two beams when said seismic mass is subjected to an acceleration.
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Accused Products
Abstract
A low-cost pendular non-serviced accelerometer comprises a base, a pendular seismic mass connected to the base by a hinged connection for pivotal movement of the seismic mass about an axis along a sense direction perpendicular to the hinged connection and a sensor connecting the seismic mass to the base. The sensor comprises at least two vibrating beams of piezo-electric material, each connected to the base at an end thereof and to the seismic mass at the other end thereof, and each provided with electrodes for vibrating the respective beam at a tuning frequency thereof. The beams are directed orthogonally to the sense axis and are located symmetrically with respect to the seismic mass on both sides of the hinged connection, whereby any acceleration along the sense axis creates tractive stresses in one beam and compression stresses in the other beam. A circuit connected to the electrodes and is arranged for delivering a signal which is responsive to the difference between the resonant frequencies of the two beams when the seismic mass is subjected to an acceleration.
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Citations
7 Claims
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1. Pendular accelerometer comprising a base, a pendular seismic mass of flat shape connected to the base by a flexure hinged connection for pivotal movement of said seismic mass about a hinge axis perpendicular to major surfaces of said pendular seismic mass, along a sense direction perpendicular to the hinge axis of the hinged connection and sensor means connecting the seismic mass to the base, wherein said sensor means comprises:
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at least two vibrating beams of piezo-electric material, each connected to the base at an end thereof and to the seismic mass at the other end thereof, and each provided with electrode means for vibrating the respective beam at a tuning frequency thereof, said beams being directed orthogonally to the same axis and being located symmetrically with respect to the seismic mass on both sides of the hinge axis of the hinged connection, whereby any acceleration along the sense axis creates tractive stresses in one beam and compression stresses in the other beam, and circuit means connected to the electrodes and arranged for delivering a signal which is responsive to the difference between the resonant frequencies of the two beams when said seismic mass is subjected to an acceleration. - View Dependent Claims (2, 3, 4, 5)
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6. Pendular accelerometer comprising:
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a base; a pendular seismic mass of flat shape connected to the base by a hinged connection for pivotal movement of said seismic mass about a hinge axis perpendicular to major surfaces of said seismic mass, along a sense direction perpendicular to the hinge axis of the hinged connection; and two vibrating beams of piezo-electric material, each connected to the base at an end thereof and to the seismic mass at the other end thereof, and each provided with electrode means for vibrating the respective beam at a tuning frequency thereof, said beams being directed orthogonally to the sense axis and being located symmetrically with respect to the seismic mass on both sides of the hinge axis of the hinged connection, whereby any acceleration along the sense axis creates tractive stresses in one beam and compression stresses in the other beam, wherein said seismic mass consists of mutually connected portions of three sheets of said piezoelectric material stacked in the direction of said hinge axis, the end ones of said sheets being formed with respective mutually aligned hinges constituting said hinge connection and the central one of said sheets being integral with said vibrating beams. - View Dependent Claims (7)
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Specification