Patent US2454567A successfully refreshed from Google Patents.
US3752189A
Expired / Lapsed
US
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Electrical feedback servovalve
Assignee: Moog Inc
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Filing: 1971-09-15
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Granted: 1973-08-14
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Expires: 1991-09-15
Abstract
Abstract An electrical feedback signal for an electrohydraulic servovalve is provided by electrical strain gauge means influenced by the bending of a cantilever beam one end of which is constrained to move in a frictionless manner with the output stage valve member of the servovalve, said strain gauge means including a strain sensitive element having a resistance value varied by bending of said beam thereby to generate an electrical feedback signal proportional to the displacement of said valve member which is operatively associated with the electrical command signal for the servovalve.
Inventors
- 👤 J Marr
- 👤 R Maskrey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:23
CPC Classifications
F; F15; F15B; F15B13/00; F15B13/16; Y; Y10; Y10T; Y10T137/00; Y10T137/8593; Y10T137/86493; Y10T137/86574; Y10T137/86622
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
108 words
In an electrical feedback servovalve having an input stage including an electrical force motor responsive to an electrical command signal, and an output stage including a body and a valve member arranged in said body to move relative to said body in response to the operation of said motor, the improvement which comprises a cantilever beam having a fixed end and a movable end, means mounting said fixed end on said body, means connecting said movable end in a substantially frictionless manner to said member for movement therewith, such movement bending said beam, and electrical strain gauge means for generating an electrical feedback signal responsive to said bending.
Claim 2
Dependent Claim
108 words
In an electrical feedback servovalve having an input stage including an electrical force motor responsive to an electrical command signal, and an output stage including a body and a valve member arranged in said body to move relative to said body in response to the operation of said motor, the improvement which comprises a cantilever beam having a fixed end and a movable end, means mounting said fixed end on said body, means connecting said movable end in a substantially frictionless manner to said member for movement therewith, such movement bending said beam, and electrical strain gauge means for generating an electrical feedback signal responsive to said bending.
Claim 3
Dependent Claim
37 words
A servovalve according to claim 1 wherein said valve member is a slidable spool, and said movable end of said beAm is connected by said connecting means to said spool symmetrically with respect to the length thereof.
Claim 4
Dependent Claim
43 words
A servovalve according to claim 1 wherein said electrical strain gauge means comprises electrical circuitry including a strain sensitive resistance element having a resistance value varied by said bending, said circuitry being arranged to produce said electrical feedback signal proportional to resistance variation.
Claim 5
Dependent Claim
36 words
A servovalve according to claim 3 wherein said circuitry includes at least two strain sensitive resistance elements mounted on said beam so that one is subjected to compression and the other to tension during such bending.
Claim 6
Dependent Claim
25 words
A servovalve according to claim 4 wherein said two strain sensitive resistance elements are mounted directly opposite each other on opposite sides of said beam.
Claim 7
Dependent Claim
14 words
A servovalve according to claim 5 wherein said circuitry is a wheatstone bridge circuit.
Claim 8
Dependent Claim
90 words
A servovalve according to claim 1 wherein said electrical strain gauge means comprises four strain sensitive resistance elements arranged in a wheatstone bridge circuit having two branches each including two of said elements mounted on said beam so that one of said elements from each of said branches is subjected to compression and the other of said elements from each of said branches is subjected to tension during said bending thereby to vary the resistance values of said four elements and produce said electrical feedback signal proportional to resistance variation.
Claim 9
Dependent Claim
39 words
A servovalve according to claim 1 wherein said connecting means includes a spherical element on said movable end of said beam and received in a recess provided in said valve member and rollingly engaging a wall of said recess.
Claim 10
Dependent Claim
35 words
An electrical feedback servovalve according to claim 8 which further comprises means supporting said fixed end of said beam and removably mounted on said body and including an electrical connector for said strain gauge means.
Claim 11
Dependent Claim
30 words
An electrical feedback servovalve according to claim 9 wherein said supporting means, beam, spherical element, strain gauge means and connector constitute a modular transducer assembly removably mounted on said body.
Claim 12
Dependent Claim
29 words
A servovalve according to claim 10 wherein said valve member is a slidable spool and said recess therein is located symmetrically with respect to the length of said spool.
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) | 1976-08-13 | 1977-02-12 | 1977-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-13 | 1981-02-12 | 1981-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-13 | 1985-02-12 | 1985-08-14 | $7700.00 | Window Closed / Lapsed |