Four bar resonating force transducer
First Claim
1. A resonant element adapted to be secured to a mounting structure in a force sensing transducer, said resonant element comprising:
- a generally planar substrate having three elongated slots formed therein defining four generally parallel, spaced-apart beams including a pair of inner beams and a pair of outer beams, said inner pair of beams and said outer pair of beams all joined together at opposite ends by integrally-formed end portions; and
means for coupling said beams to an excitation source, said coupling means being responsive to the excitation source for causing said outer beams to vibrate generally in phase and out of plane relative to said substrate while said inner beams vibrate out of plane and generally in phase with each other, but out of phase with said outer beams.
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Accused Products
Abstract
A force sensing element is formed with four vibrating beams having substantially the same width and length. The four beams are spaced apart and disposed parallel to one another and are connected at opposite ends by end portions. With such a configuration, the outer beams move in phase with each other but 180° out of phase with the inner beams. As such, the linear and angular reaction forces at the end portions are effectively cancelled. One advantage of such a configuration is its relative insensitivity to manufacturing process variations. By utilizing four beams which are nearly identical in width, variation in fabrication tolerance has virtually an equal effect on beam mass such that the dynamic balance of the force sensing element is maintained to a high degree of accuracy. Various drive methodologies for the force sensing element are disclosed as well as force sensing elements with integrally-formed isolator systems.
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Citations
64 Claims
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1. A resonant element adapted to be secured to a mounting structure in a force sensing transducer, said resonant element comprising:
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a generally planar substrate having three elongated slots formed therein defining four generally parallel, spaced-apart beams including a pair of inner beams and a pair of outer beams, said inner pair of beams and said outer pair of beams all joined together at opposite ends by integrally-formed end portions; and means for coupling said beams to an excitation source, said coupling means being responsive to the excitation source for causing said outer beams to vibrate generally in phase and out of plane relative to said substrate while said inner beams vibrate out of plane and generally in phase with each other, but out of phase with said outer beams. - View Dependent Claims (2, 3, 4, 7, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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5. A resonant element adapted to be secured to a mounting structure in a force sensing transducer, said resonant element comprising:
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a generally planar substrate having three elongated slots formed therein defining four generally parallel, spaced-apart beams including a pair of inner beams and a pair of outer beams each joined at opposite ends by integrally-formed end portions; means for coupling said beams to an excitation source, said coupling means being responsive to the excitation source for causing said outer beams to vibrate generally in phase and out of plane relative to said substrate while said inner beams vibrate out of plane and generally in phase with each other, but out of phase with said outer beams; and means including a bridge interconnecting said inner beams for synchronizing the vibration of said inner beams, wherein said bridge interconnecting said inner beams is generally centrally located along the lengths of said inner beams. - View Dependent Claims (6)
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8. A resonant element adapted to be secured to a mounting structure in a force sensing transducer, said resonant element comprising:
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a generally planar substrate having three elongated slots formed therein defining four generally parallel, spaced apart beams including a pair of inner beams and a pair of outer beams each joined at opposite ends by integrally formed end portions; means for coupling said beams to an excitation source, said coupling means being responsive to the excitation source for causing said outer beams to vibrate generally in phase and out of plane relative to said substrate while said inner beams vibrate out of plane and generally in phase with each other, but out of phase with said outer beams; and means for reducing the bending of said end portions caused by the vibration of said beams. - View Dependent Claims (9, 10)
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25. A resonant element adapted to be secured to a mounting structure in a force sensing transducer, said resonant element comprising:
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a generally planar substrate having three elongated slots formed therein defining four generally parallel, spaced apart beams including a pair of inner beams and a pair of outer beams each joined at opposite ends by integrally formed end portions; means for coupling said beams to an excitation source, said coupling means being responsive to the excitation source for causing said outer beams to vibrate generally in phase and out of plane relative to said substrate while said inner beams vibrate out of plane and generally in phase with each other, but out of phase with said outer beams, wherein said substrate has an edge and a predetermined thickness and is formed from a non-conductive material, and wherein said coupling means includes a plurality of conductive traces formed on said beams wherein at least a portion of the conductive traces is disposed along a portion of said edge of said substrate; and means for generating a magnetic field in a direction generally perpendicular to the beams. - View Dependent Claims (26, 27)
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28. A resonant element adapted to be secured to amounting structure in a force sensing transducer, said resonant element comprising:
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a generally planar substrate having three elongated slots formed therein defining four generally parallel, spaced apart beams including a pair of inner beams and a pair of outer beams each joined at opposite ends by integrally formed end portions; and means for coupling said beams to an excitation source, said coupling means being responsive to the excitation source for causing said outer beams to vibrate generally in phase and out of plane relative to said substrate while said inner beams vibrate out of plane and generally in phase with each other, but out of phase with said outer beams, wherein said coupling means includes means for exciting said beams including a plurality of conductive traces adapted to be connected to a source of electrical energy and means for applying a magnetic field in a direction generally perpendicular to said beams. - View Dependent Claims (29, 30, 31, 32)
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33. A force sensing element for use in a transducer, said force sensing element comprising:
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a piezoelectric substrate formed with a plurality of generally parallel, spaced-apart beams connected at opposite ends to form end portions; a plurality of first conductive traces forming an electrode pattern disposed on each of said plurality of beams; a plurality of second conductive traces forming an electrode pattern disposed on each of said plurality of beams, wherein said second conductive traces cross over said first conductive traces at predetermined crossover points; and means for insulating said first conductive traces from said second conductive traces at said crossover points. - View Dependent Claims (34, 35)
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36. A force sensing element for use in a transducer, said force sensing element comprising:
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a piezoelectric substrate formed with a plurality of generally parallel, spaced apart beams connected at opposite ends to form end portions; a plurality of first conductive traces forming an electrode pattern disposed on each of said plurality of beams; a plurality of second conductive traces forming an electrode pattern disposed on each of said plurality of beams, wherein said second conductive traces crossover said first conductive traces at predetermined crossover points; and means for insulating said first conductive traces from said second conductive traces at said crossover points, wherein said first conductive traces and said second conductive traces are formed on a single plane. - View Dependent Claims (39, 40, 41, 42)
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37. A force sensing element for use in a transducer, said force sensing element comprising:
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a substrate having four generally parallel and spaced-apart beams formed thereon, including a pair of inner beams and a pair of outer beams connected at opposite ends thereof to a common portion; mounting pads, coupled to said end portions at each end; and means for isolating said mounting pad portions from forces in said end portions. - View Dependent Claims (38, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53)
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54. A vibrating tine resonator for use as a transducer or the like, said resonator comprising:
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a unitary body cut from flat, planar stock and having a generally uniform thickness; said body including spaced apart end portions; and said body including a tine system extending between said end portions; said vibrating tine resonator being characterized by; said tine system including a pair of similar tine arrays separated by a slot and extending side-by-side between said end portions; each array including a pair of tines extending parallel to one another; and a bridge portion spanning said slot and joining adjacent tines of said two arrays. - View Dependent Claims (55, 56, 57, 58, 59, 60, 61, 62, 63, 64)
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Specification