Abstract:
A force sensing assembly and particularly one which is especially suitable for use as a pressure transducer is disclosed herein. This assembly includes at least one and preferably a stacked pair of resonating type force sensing devices supported from one end in a cantilvered fashion.
Abstract:
An oscillating crystal force transducer and method of making the same are provided, the transducer comprising support structure, a plate-shaped piezo-electric crystal having opposed sides and a peripheral edge extending between the opposed sides, and two seating members carried by the support structure and respectively engaging the peripheral edge of the crystal and arranged to apply a force to the crystal along a line extending through the crystal from one of the seating members to the other of the seating members, the support structure comprising a looped spring member having opposed ends spaced from each other to define the mouth of the looped spring member and respectively carrying the seating members whereby the crystal is disposed in the mouth of the looped spring member between the seating members thereof.
Abstract:
A force transducer device adapted to function in a system having electrical means to cause the device to oscillate at its natural resonant frequency and means to monitor said frequency, the device having an intermediate resilient member being capable of mechanically oscillating at a natural resonant frequency, at least two piezoelectric transducers mounted on said resilient member and means for connecting the transducer sheets into said system, is disclosed herein.
Abstract:
A force sensor comprising a resonator (10) having a frequency that varies with the force being measured. The resonator includes an oscillatory bar (101, 102) and a pair of anchor members (12, 103, 104) that are connected each to a corresponding end portion of the bar and which are adapted to apply the force having to be measured to the bar. The sensor further comprises a tube (16) that surrounds the resonator and which is rigidly secured by its end portions to the anchor members (12).
Abstract:
A force transducer having a vibratory member either a beam or a string and means for effectively isolating the vibratory member from its end mounts over the range of its operating frequencies to eliminate energy loss to the mounts. The axial stresses, either tension or compression, are directly transferred to the vibratory member to affect its natural resonant frequency. Isolation at vibration frequencies is effected by the cooperation of combined isolator masses and isolator springs with the vibratory member. The isolator masses comprise two bars extending from each end support of the vibratory member, each being coextensive with a portion of the support member. The pairs of masses are axially separated. The isolator springs comprise two single thin, spaced resilient members, each isolator spring connecting a single end support of the member and a single transducer end mount.
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.
Abstract:
A piezoelectric sensor assembly for measuring a force quantity on a structure includes at least one piezoelectric sensor, each including an element and two electrodes each projecting outward from the element. An electronic processor of the assembly is configured to receive data from the sensor, wherein the data includes a voltage with a magnitude that is indicative of a dynamic load (i.e., amplitude modulation mode) placed upon the structure. The processor may be configured to interrogate the piezoelectric sensor for its resonant frequency change which is indicative of the load applied to the structure at low operation frequency and to which the piezoelectric sensor would not otherwise respond well. The dual mode operation of the piezoelectric sensor extends the frequency range of the strain measurement from the dynamic range to static or quasi-static range.
Abstract:
II s'agit d'un capteur de micro-force comportant une plaque monolithique comprenant une première zone (1') délimitant un premier évidement (1), devant être maintenue en position par rapport à un support, une seconde zone (2') reliée à la première zone (1') délimitant le premier évidement (1) et un second évidement (2), une poutre de mesure (4) en travers du premier évidement (1) ayant une première extrémité (40) encastrée à la première zone (1') et une seconde extrémité (41) reliée à la seconde zone (2'), une poutre d'excitation (3) en travers du second évidement (2) ayant deux extrémités encastrées à la seconde zone (2), étant équipée d'au moins un élément d' excitation (5), une troisième zone (8) reliée à la première zone (1') et une poutre effectrice (7) présentant une extrémité libre (9) devant recevoir la force (F) à mesurer et une extrémité encastrée (9') à la troisième zone (8), une quatrième zone (15) reliant l'extrémité encastrée (9') de la poutre effectrice (7) à la seconde extrémité (41) de la poutre de mesure (4) qui est équipée d'un élément de mesure (6).