Patent US4016437A successfully refreshed from Google Patents.
US4016437A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Piezoelectric pressure and force transducers or accelerometers
Assignee: Kistler Instrumente AG
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Filing: 1976-01-28
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Granted: 1977-04-05
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Expires: 1996-01-28
Abstract
Abstract A piezoelectric transducer element which can be used in force and pressure transducers is made from a quartz element which is prestressed within the transducers. The prestress is applied within a certain orientation with respect to the lattice plane (0 4 4 3). The transducer may include both disc and rod-shaped quartz elements.
Inventors
- 👤 Reto Calderara
- 👤 Hans U. Baumgartner
- 👤 Jan Tichy
- 👤 Hans C. Sonderegger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 15:39
CPC Classifications
G; G01; G01P; G01P15/00; G01P15/02; G01P15/08; G01P15/09; G01P15/0907; G01L; G01L1/00; G01L1/16; F; F02; F02B; F02B1/00; F02B1/02; F02B1/04
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
111 words
A piezoelectric transducer for use in force, pressure and acceleration measuring systems comprising: at least one transducer element which is prone to twinning; means for introducing a force to said element; and means for applying a prestress to said element in at least one direction forming an angle of less than 27° with a direction providing a maximum difference between respective elasticity coefficients of said element for stable and unstable twin forms of said element such that the stable form obtains a thermodynamic preference according to the relationship ##EQU6## wherein G represents the elastic free enthalpy, s represents the elastic compliance coefficients of said transducer element, and T represents stress components.
Claim 2
Dependent Claim
111 words
A piezoelectric transducer for use in force, pressure and acceleration measuring systems comprising: at least one transducer element which is prone to twinning; means for introducing a force to said element; and means for applying a prestress to said element in at least one direction forming an angle of less than 27° with a direction providing a maximum difference between respective elasticity coefficients of said element for stable and unstable twin forms of said element such that the stable form obtains a thermodynamic preference according to the relationship ##EQU6## wherein G represents the elastic free enthalpy, s represents the elastic compliance coefficients of said transducer element, and T represents stress components.
Claim 3
Dependent Claim
39 words
A piezoelectric transducer according to claim 1, wherein said prestress is applied in a direction forming said angle of less than 27° with respect to the normal to the crystallographic lattice plane (0 4 4 3) of said element.
Claim 4
Dependent Claim
52 words
A piezoelectric transducer element according to claim 1, wherein said at least one transducer element is a disc-shaped longitudinal quartz element and includes electrodes mounted on respective surfaces thereof, said surfaces forming an angle of from about 0° to 27° with the crystallographic lattice plane (0 4 4 3) of said element.
Claim 5
Dependent Claim
35 words
A piezoelectric transducer according to claim 3, wherein the surfaces on which said electrodes are mounted form an angle of less than 27° with the crystallographic lattice plane (1 3 2 2) of said element.
Claim 6
Dependent Claim
23 words
A piezoelectric transducer according to claim 4, wherein said longitudinal quartz element has an orientation of approximately Y Z l 20° w 30°.
Claim 7
Dependent Claim
54 words
A piezoelectric transducer according to claim 1, wherein said at least one transducer element is a rod-shaped transverse quartz element, said rod-shaped element having a longitudinal axis at an angle of from about 0° to about 27° with respect to the normal to the crystallographic lattice plane (0 4 4 3) of said element.
Claim 8
Dependent Claim
20 words
A piezoelectric transducer according to claim 6, wherein said at least one rod-shaped transducer element has a segmented cross section.
Claim 9
Dependent Claim
19 words
A piezoelectric transducer according to claim 6, wherein said rod-shaped transducer element has the form of a hollow half-cylinder.
Claim 10
Dependent Claim
29 words
A piezoelectric transducer according to claim 6, wherein the longitudinal axis of said rod-shaped quartz element forms a right angle to said crystallographic lattice plane (0 4 4 3).
Claim 11
Dependent Claim
21 words
A piezoelectric transducer according to claim 6, wherein said transverse quartz element has an orientation of approximately X Y t 30°.
Claim 12
Dependent Claim
39 words
A piezoelectric transducer according to claim 1, wherein said means for applying said prestress forms a preload on said transducer element in said at least one direction, said preload preventing formation of said twinned form in said transducer element.
Claim 13
Dependent Claim
26 words
A piezoelectric transducer according to claim 1, wherein said means for introducing a force to said element includes means for applying a prestress to said element.
Claim 14
Dependent Claim
19 words
A piezoelectric transducer according to claim 12, wherein said means for introducing a force include means for applying pressure.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-04-04 | 1980-10-04 | 1981-04-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-04-04 | 1984-10-04 | 1985-04-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-04-04 | 1988-10-04 | 1989-04-05 | $7700.00 | Window Closed / Lapsed |