US4384230A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital piezoelectric actuator
Assignee: RTX Corp
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Filing: 1980-11-06
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Granted: 1983-05-17
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Expires: 2000-11-06
Abstract
Abstract A linear extension piezoelectric actuator comprises a displacement generator having a plurality of discrete groups of piezoelectric material segments disposed coaxially along the extension axis of the actuator, each group being energized separately by voltage excitation signals from an external source to provide a corresponding one of a plurality of extension increments which in summation provide the total range of extension along the extension axis.
Inventors
- 👤 George R. Wisner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:14
CPC Classifications
H; H10; H10N; H10N30/00; H10N30/50; H10N30/503; H02; H02N; H02N2/00; H02N2/02; H02N2/06; H10N30/80; H10N30/802; H10N30/87; H10N30/871
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
172 words
A linear actuator with piezoelectric displacement generator for linearly extending and retracting over a total range of extension along an extension axis thereof in response to voltage excitation signals presented from an external voltage signal source, comprising: housing means for providing a compressive load along the extension axis of the displacement generator; coupling means, disposed in said housing and responsive to the displacement generator for providing an output manifestation of the extension and retraction thereof; as characterized by: a displacement generator having discrete groups of piezoelectric material segments disposed coaxially in tandem along the extension axis, each group separately connected for response to bistable state voltage excitation signals presented individually thereto from the external voltage source in alternate extended state and quiescent state magnitudes, each group responding by alternately extending and retracting linearly along the extension axis in correspondence with said extended and quiescent state magnitudes, whereby the instant lineal sum of the extended and retracted states of all of said groups of segments define the instant actual extension of the actuator.
Claim 2
Dependent Claim
172 words
A linear actuator with piezoelectric displacement generator for linearly extending and retracting over a total range of extension along an extension axis thereof in response to voltage excitation signals presented from an external voltage signal source, comprising: housing means for providing a compressive load along the extension axis of the displacement generator; coupling means, disposed in said housing and responsive to the displacement generator for providing an output manifestation of the extension and retraction thereof; as characterized by: a displacement generator having discrete groups of piezoelectric material segments disposed coaxially in tandem along the extension axis, each group separately connected for response to bistable state voltage excitation signals presented individually thereto from the external voltage source in alternate extended state and quiescent state magnitudes, each group responding by alternately extending and retracting linearly along the extension axis in correspondence with said extended and quiescent state magnitudes, whereby the instant lineal sum of the extended and retracted states of all of said groups of segments define the instant actual extension of the actuator.
Claim 3
Dependent Claim
76 words
The actuator of claim 1, wherein the number of piezoelectric segments in each group are substantially equal to binary multiples of the number of segments in each other group, from a least significant bit (LSB) equivalent number to a most significant bit (MSB) equivalent number, the segments in each group being simultaneously responsive to said bistable state excitation signals applied to said group, whereby the actual extension of the actuator is provided in a binary progression.
Claim 4
Dependent Claim
72 words
The actuator of claim 1, wherein said groups are each connected for response to equal extended state and quiescent state magnitude voltage excitation signals and comprise equal number piezoelectric material segments for providing equal value extension increments, whereby the instantaneous actual extension value of the actuator is equal to the instantaneous lineal sum of the individual group extension increments as manifested by a present number of individual extended state magnitude excitation signals.
Claim 5
Dependent Claim
20 words
The actuator of claims 1, 2 or 3, wherein said quiescent state excitation signal magnitude is equal to zero VDC.
Claim 6
Dependent Claim
166 words
The actuator of claim 1, wherein said group piezoelectric material segments each comprise a pair of piezoelectric wafer elements, each wafer having parallel high potential and low potential surfaces defined in respect to the direction of polarization of the wafer, the wafers of each segment being coaxially disposed along the extension axis of said displacement generator with said high potential surfaces of each bonded to either side of a central high potential electrode and said low potential surfaces of each bonded to one side of a related one of two low potential electrodes associated therewith, the other side of each of said low potential electrodes being bonded to the low potential surfaces of an immediately preceding and an immediately succeeding segment in said group to provide a tandem cascade of oppositely polarized wafers interleaved with alternating high potential and low potential electrodes along the extension axis, said high potential and low potential electrodes each connected for response to the voltage excitation signals from the external source.
Claim 7
Dependent Claim
57 words
The actuator of claim 5, wherein said displacement generator demarcates each of said groups from among said tandem cascade of piezoelectric segments by a common electrical connection of the high potential electrodes of the segments associated with each group, which is electrically isolated from the common electrical connection of the high potential electrodes of each other group.
Claim 8
Dependent Claim
33 words
The actuator of claim 5, wherein said high potential electrode and said low potential electrodes of each segment comprise a conductive metal alloy bonded to the associated wafer surface with a conductive epoxy.
Claim 9
Dependent Claim
12 words
The actuator of claim 7, wherein said conductive metal alloy is berylium-copper.
Claim 10
Dependent Claim
14 words
The actuator of claim 5, wherein said piezoelectric material wafers comprise lead zirconate titanate.
Claim 11
Dependent Claim
13 words
The actuator of claim 5, wherein said piezoelectric material wafers comprise barium titanate.
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) | 1986-05-16 | 1986-11-15 | 1987-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-05-16 | 1990-11-15 | 1991-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-05-16 | 1994-11-15 | 1995-05-17 | $7700.00 | Window Closed / Lapsed |