Longitudinal isolation system for flexurally vibrating force transducers
First Claim
1. In a vibrating beam force transducer having an elongated, resilient beam, drive means for causing said beam to vibrate at a resonant frequency which is a function of the longitudinal force applied to said beam, a pair of mounting pads and mounting means for connecting the ends of said beam to respective mounting pads such that forces applied to said mounting pads toward and away from each other apply longitudinal forces to said beam to vary the resonant frequency of said beam, the improvement comprising longitudinal isolation means associated with said mounting means for facilitating movement of the ends of said beam toward and away from each other responsive to vibration of said beam thereby isolating said mounting pads from longitudinal movement of the ends of said beam while allowing forces applied between said mounting pads to be transmitted to said beam.
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Abstract
A system for isolating the mounting pads of a vibrating beam or tuning fork force transducers from longitudinal vibrations generated by transverse vibrations of the beam or tuning fork tines which extend between the mounting pads. The system includes an arrangement of longitudinally resilient support links and masses that flex responsive to change in the length of the beam or tines as the beam or tines vibrate transversely. The support links and masses thus isolate the mounting pads from the longitudinally vibrations of the beam or tuning fork tines while allowing transmission of forces applied between the mounting pads which vary the force dependent resonant frequency of the beam or tuning fork.
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Citations
15 Claims
- 1. In a vibrating beam force transducer having an elongated, resilient beam, drive means for causing said beam to vibrate at a resonant frequency which is a function of the longitudinal force applied to said beam, a pair of mounting pads and mounting means for connecting the ends of said beam to respective mounting pads such that forces applied to said mounting pads toward and away from each other apply longitudinal forces to said beam to vary the resonant frequency of said beam, the improvement comprising longitudinal isolation means associated with said mounting means for facilitating movement of the ends of said beam toward and away from each other responsive to vibration of said beam thereby isolating said mounting pads from longitudinal movement of the ends of said beam while allowing forces applied between said mounting pads to be transmitted to said beam.
- 4. In a vibrating beam force transducer having a pair of mounting pads, an elongated, resilient beam extending between a pair of base members, each of which carries an isolation mass at opposite ends thereof, a pair of resilient lateral isolation members extending perpendicularly from each of said base members at opposite ends thereof, said lateral isolation members resonating with said isolation masses at a frequency substantially lower than the resonant frequency of said beam, thereby isolating said mounting pads from lateral isolation of said beam, drive means for causing said beam to vibrate at a resonant frequency which is a function of the longitudinal force applied to said beam, a pair of mounting pads and mounting means for connecting the ends of said beam to respective mounting pads such that forces applied to said mounting pads toward and away from each other apply longitudinal forces to said beam to vary the resonant frequency of said beam, the improvement comprising longitudinal isolation means positioned between at least one of said base members and its respective mounting pad to facilitate movement of said base member toward and away from its mounting pad as said beam flexes.
- 9. In a vibrating beam force transducer having a pair of mounting pads, an elongated, resilient beam extending between a pair of base members, each of which carries an isolation mass at opposite ends thereof, a pair of resilient lateral isolation members extending perpendicularly from each of said base members at opposite ends thereof, said lateral isolation members resonating with said isolation masses at a frequency substantially lower than the resonant frequency of said beam, thereby isolating said mounting pads from lateral isolation of said beam, drive means for causing said beam to vibrate at a resonant frequency which is a function of the longitudinal force applied to said beam, and mounting means for connecting the ends of said beam to respective mounting pads such that forces applied to said mounting pads toward and away from each other apply longitudinal forces to said beam to vary the resonant frequency of said beam, the improvement comprising longitudinal isolation means associated with said mounting means for facilitating movement of the ends of said beam toward and away from each other responsive to vibration of said beam, thereby isolating said mounting pads from longitudinal movement of the ends of said beam while allowing forces applied between said mounting pads to be transmitted to said beam, said longitudinal isolation means including a first pair of resilient, elongated support members positioned between at least one end of said beam and its respective base member, and a second pair of resilient elongated support members positioned between at least one of said lateral isolation members and its respective mounting pad, said support members being relatively compliant in the longitudinal direction and relatively stiff in the lateral direction in the plane of vibration of said beam to facilitate movement of the ends of said beam toward and away from each other and the movement of said base member toward and away from respective mounting pads as said beam flexes.
- 11. In a vibrating beam force transducer having a pair of mounting pads, an elongated, resilient beam extending between a pair of base members, each of which carries an isolation mass at opposite ends thereof, a pair of resilient lateral isolation members extending perpendicularly from each of said base members at opposite ends thereof, said lateral isolation members resonating with said isolation masses at a frequency substantially lower than the resonant frequency of said beam, thereby isolating said mounting pads from lateral isolation of said beam, drive means for causing said beam to vibrate at a resonant frequency which is a function of the longitudinal force applied to said beam, and mounting means for connecting the ends of said beam to respective mounting pads such that forces applied to said mounting pads toward and away from each other apply longitudinal forces to said beam to vary the resonant frequency of said beam, the improvement comprising longitudinal isolation means associated with said mounting means for facilitating movement of the ends of said beam toward and away from each other responsive to vibration of said beam, thereby isolating said mounting pads from longitudinal movement of the ends of said beam while allowing forces applied between said mounting pads to be transmitted to said beam, said longitudinal isolation means including a first pair of resilient, elongated support members positioned between at least one end of said beam and its respective base member, and a second pair of resilient, elongated support members positioned between at least one of said lateral isolation members and its respective base member, said support members being relatively stiff in the lateral direction in the plane of vibration of said beam to facilitate movement of the ends of said beam toward and away from each other and the movement of said base member toward and away from respective mounting pads as said beam flexes.
- 13. In a tuning fork force transducer including a tuning fork having a pair of flexible tuning fork tines projecting between tuning fork stems, drive means for causing said tines to vibrate at a resonant frequency which is a function of the longitudinal force applied to said tines, a first mounting pad to which said first stem is secured, a second mounting pad to which second said stem is attached such that forces applied to said mounting pads toward and away from each other apply longitudinal forces to the tines of said tuning fork to vary the resonant frequency of said tuning fork, the improvement comprising longitudinal isolation means for allowing movement of the free ends of said tuning fork toward and away from said mounting pads responsive to vibration of said tuning fork thereby isolating said mounting pads from longitudinal movement of the free ends of said tines with respect to said stem while allowing forces applied between said mounting pads to be transmitted to said tines.
Specification