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Patent

Isolating and temperature compensating system for resonators

28 Jan 1980-
TL;DR: In this paper, a mounting structure for crystal resonators used as frequency standards and transducers which maximizes performance and reduces the sensitivity to environmental errors is presented. But, the mounting structure is not suitable for high-frequency transducers.
Abstract: A mounting structure for crystal resonators used as frequency standards and transducers which maximizes performance and reduces the sensitivity to environmental errors. In one embodiment, force sensitive crystal resonators having inherent unmounted temperature sensitivities are used in conjunction with reactive spring-like mounting arrangements having predetermined temperature stress characteristics such that the thermally induced mechanical stress of the mounting arrangements changes, compensates, and optimizes the overall combined temperature characteristics. In another embodiment crystal resonators are isolated from the external environment so that they are capable of sensing forces while operating in a vacuum or inert atmosphere. Environmental isolation is provided by bellows and/or diaphragm arrangements used alone or in conjunction with air-tight enclosures which enable forces to be applied to stress-sensitive crystals while isolating the crystals from the external force producing environment.
Citations
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Patent
30 May 1985
TL;DR: In this paper, an apparatus for measuring pressure within a conduit is disclosed, consisting of a tube whose resonant frequency varies with the pressure of fluid within the tube; means for passing the fluid to be measured through the tube, two active piezoelectric films disposed in intimate contact with the tube on opposite sides thereof; first electronic means for energizing the first one to cause the tube to resonate at its natural frequency, and second electronic means connected to the other of the films to monitor the frequency of the tube.
Abstract: An apparatus for measuring pressure within a conduit is disclosed preferably comprising a tube whose resonant frequency varies with the pressure of fluid within the tube; means for passing the fluid to be measured through the tube; two active piezoelectric films disposed in intimate contact with the tube on opposite sides thereof; first electronic means for energizing the first of the films to cause the tube to resonate at its natural frequency, and second electronic means connected to the other of the films to monitor the frequency of the tube.

96 citations

Patent
14 May 2001
TL;DR: In this paper, a digital angular rate and acceleration sensor is constructed with force-sensitive resonators positioned longitudinally on one or both sides of the neutral bending plane of a cantilevered structure.
Abstract: A digital angular rate and acceleration sensor is constructed with force-sensitive resonators positioned longitudinally on one or both sides of the neutral bending plane of a cantilevered structure. The cantilevered structure has an inertial proof mass at its free end with a periodic velocity applied sideways to the bending plane. Rotation about the longitudinal axis, which produces periodic Coriolis acceleration, as well as inertial acceleration applied perpendicular to the bending plane, generate tensile and compressive forces on the resonators thereby altering the resonant frequencies that are thus a measure of angular rate of rotation and acceleration.

39 citations

Patent
19 May 1993
TL;DR: In this paper, the authors present a counting scale which implements a load cell assembly for the measurement of weight used in counting calculations, where a controller is included in the assembly to drive these resonators, convert their frequency outputs to digital values, and correct for various environmental effects, to obtain an accurate weight measurement for use in counting scale.
Abstract: The invention is directed to a counting scale which implements a load cell assembly for the measurement of weight used in counting calculations. A load cell in such an assembly has a beam structure with beams positioned parallel to each other in at least one plane. Generally, these parallel beams are attached to a stationary base and have sensing means attached between the two beams and the base. These sensing means are preferably resonators which have resonant frequencies that vary in response to an applied force on the load cell. A controller is included in the assembly to drive these resonators, convert their frequency outputs to digital values, and correct for various environmental effects, to obtain an accurate weight measurement for use in the counting scale.

35 citations

Patent
30 Nov 2006
TL;DR: In this paper, a pump for moving a liquid including a rotor rotatable within a housing and slidable relative to the housing between a first axial rotor position during normal pump operation and a second one during a pump inoperative condition is described.
Abstract: A pump for moving a liquid including a rotor rotatable within a housing and slidable relative to the housing between a first axial rotor position during normal pump operation and a second axial rotor position during a pump inoperative condition.

33 citations

PatentDOI
TL;DR: In this paper, a coplanar two-dimensional compliant mounting structure (100, 120) was proposed for improving the aging, pressure sensitivity, and acceleration sensitivity of crystal resonators.
Abstract: The invention is a method and apparatus for improving the aging, pressure sensitivity, and acceleration sensitivity of crystal resonators (5). In one embodiment the invention includes a coplanar two-dimensional compliant mounting structure (100, 120), wherein the symmetry and compliance of the planar mounting structure (100, 120) reduces the effects of residual static stresses and dynamic vibratory stresses on the vibration sensitivity performance of a crystal resonator (5). The structural elements include compliance loops (120) that provide relief from the effects associated with manufacturing, thermal and vibration stresses.

32 citations

References
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Patent
20 Apr 1979
TL;DR: In this article, a piezoelectric quartz force transducer having the shape of a double-ended tuning fork is described, which was used for tuning a tuning fork.
Abstract: The invention relates to a piezoelectric quartz force transducer having the shape of a double-ended tuning fork.

81 citations

Patent
22 Aug 1974
TL;DR: In this paper, a plate-like crystal is secured to a solid member in such a way that deformation in the solid manner, caused by the force or fluid pressure to be measured, results in a secondary force being transmitted to the crystal.
Abstract: A force and pressure transducer comprises a plate-like crystal. Two separate portions of the crystal are maintained in oscillation at different frequencies by a circuit. The crystal is firmly secured to a solid member in such a manner that deformation in the solid manner, caused by the force or fluid pressure to be measured, results in a secondary force being transmitted to the crystal. This compels the frequency of one of the two oscillating portions of the crystal to change substantially whereas the frequency of the other portion changes only minimally. The difference frequency between the two portions is a highly accurate measure of the force or fluid pressure to be measured. In oscillating crystal transducers hitherto employing plate-like crystals wherein the force to be measured is transmitted along the surface direction, the maximum applicable force has been limited by the ability of the crystal to sustain larger forces. The new development claimed herein permits large forces and fluid pressures to be measured.

22 citations

Patent
21 Nov 1966

18 citations

Patent
01 Jul 1976
TL;DR: A fluid pressure transducer comprises a chamber; one or more matched, plate-like crystals within the chamber; electrical means for exciting each of the crystals and means for transmitting forces originating from fluid pressures on two diaphragms located on the chamber to the crystal or crystals so as to produce a change in the resonant frequency of the crystal.
Abstract: A fluid pressure transducer comprises a chamber; one or more matched, plate-like crystals within the chamber; electrical means for exciting each of the crystals and means for transmitting forces originating from fluid pressures on two diaphragms located on the chamber to the crystal or crystals so as to produce a change in the resonant frequency of the crystal or crystals. This change is a measure of the difference in fluid pressures applied to the two diaphragms. SP This application is a continuation-in-part of my copending application Ser. No. 499,489 filed Oct. 22, 1974, now U.S. Pat. No. 4,020,448 issued Apr. 26, 1977. The specification and drawings of that prior application are hereby incorporated into this application by reference.

17 citations