US3766787A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Accelerometer for measuring angular accelerations
Assignee: Brown Brothers and Co Ltd
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Filing: 1971-07-01
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Granted: 1973-10-23
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Expires: 1991-07-01
Abstract
Abstract An angular accelerometer comprises a rotor rotatably supported in a stator by air bearings. An inductive sensor is mounted on the stator and arranged to detect displacement of the rotor from a datum relative to the stator. A torquer, comprising two coils connected in a circuit so that the currents through the coils can be varied differentially, is also mounted on the stator. The sensor and torquer are disposed transversely of a cooperating ferromagnetic bar which extends transversely on the rotor. The sensor includes two coils and has an associated source of oscillating flux so arranged that the reluctance between the source and the two coils is varied differentially when the rotor is displaced. The sensor coils are connected through a differential amplifier and a phase-sensitive detector to the torquer. The current in the torquer coils is varied differentially in response to variations of the signal from the phase-sensitive detector to produce a torque on the rotor proportional to the angular acceleration of the stator to maintain the rotor substantially in its datum position. An output provides a signal proportional to the torque to indicate the angular acceleration. The spacing between the torquer and the ferromagnetic bar is much greater than the spacing between the sensor and the bar so that there is substantially no change of reluctance between the torquer coils and the bar on a change of angular acceleration of the stator.
Inventors
- 👤 J Irvine
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 10:05
CPC Classifications
G; G01; G01P; G01P15/00; G01P15/02; G01P15/08; G01P15/13; G01P15/132; G01P15/0888
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
291 words
In an accelerometer for measuring angular accelerations and including a rotor and an output for providing a signal proportional to a torque applied to such rotor, the combination comprising: a stator; means rotatably supporting said rotor in the stator, said rotor being dynamically balanced; inductive sensing means to detect displacement of the rotor from a datum relative to the stator, the sensing means being disposed transversely of a cooperating portion of the rotor and having an associated source of oscillating flux so arranged that rotation of said cooperating portion of the rotor relative to the stator varies the reluctance between the source and the sensing means; an inductive torquer disposed transversely of a cooperating portion of the rotor and including two coils, supply terminals, an input and circuit means connecting the coils to the supply terminals to vary the current in the coils differentially in response to the signal at the input, both the sensing means and the torquer being mounted on the stator and allowing limited rotation of the rotor; a phase-sensitive detector, the sensing means being connected to the input of the torquer through the phase-sensitive detector to cause said torquer to provide said torque on the cooperating portion of the rotor disposed transversely of the torquer to maintain the rotor substantially in its datum position; the spacing between the torquer and the cooperating portion of the rotor disposed transversely of the torquer being substantially greater than the spacing between the sensing means and the cooperating portion of the rotor disposed transversely of the sensing means, whereby there is substantially no change of reluctance between the torquer coils and the cooperating portion of the rotor disposed transversely of the torquer on a change of angular acceleration of the stator.
Claim 2
Dependent Claim
291 words
In an accelerometer for measuring angular accelerations and including a rotor and an output for providing a signal proportional to a torque applied to such rotor, the combination comprising: a stator; means rotatably supporting said rotor in the stator, said rotor being dynamically balanced; inductive sensing means to detect displacement of the rotor from a datum relative to the stator, the sensing means being disposed transversely of a cooperating portion of the rotor and having an associated source of oscillating flux so arranged that rotation of said cooperating portion of the rotor relative to the stator varies the reluctance between the source and the sensing means; an inductive torquer disposed transversely of a cooperating portion of the rotor and including two coils, supply terminals, an input and circuit means connecting the coils to the supply terminals to vary the current in the coils differentially in response to the signal at the input, both the sensing means and the torquer being mounted on the stator and allowing limited rotation of the rotor; a phase-sensitive detector, the sensing means being connected to the input of the torquer through the phase-sensitive detector to cause said torquer to provide said torque on the cooperating portion of the rotor disposed transversely of the torquer to maintain the rotor substantially in its datum position; the spacing between the torquer and the cooperating portion of the rotor disposed transversely of the torquer being substantially greater than the spacing between the sensing means and the cooperating portion of the rotor disposed transversely of the sensing means, whereby there is substantially no change of reluctance between the torquer coils and the cooperating portion of the rotor disposed transversely of the torquer on a change of angular acceleration of the stator.
Claim 3
Dependent Claim
33 words
An accelerometer according to claim 1, wherein the rotor includes a ferromagnetic bar mounted transversely of the axis of rotation of the rotor, the sensing means and torquer cooperating with said ferromagnetic bar.
Claim 4
Dependent Claim
21 words
An accelerometer according to claim 2, wherein the sensing means and torquer are located on opposite sides of the ferromagnetic bar.
Claim 5
Dependent Claim
51 words
An accelerometer according to claim 1, wherein the sensing means includes two coils mounted on the stator equidistant from the axis of rotation of the rotor and the source includes an oscillator and a third coil mounted on the stator equidistant from the two sensor coils and connected to the oscillator.
Claim 6
Dependent Claim
46 words
An accelerometer according to claim 4, wherein the sensing means includes an E-shaped ferromagnetic core having two outer limbs and a central limb, the two sensing coils being mountEd on the outer limbs and the third coil being mounted on the central limb of the core.
Claim 7
Dependent Claim
23 words
An accelerometer according to claim 4, including a differential amplifier the sensing coils being connected through the differential amplifier to the phase-sensitive detector.
Claim 8
Dependent Claim
26 words
An accelerometer according to claim 4, wherein the said two coils are symmetrically disposed about a plane passing through the axis of rotation of the rotor.
Claim 9
Dependent Claim
14 words
An accelerometer according to claim 1, wherein the phase-sensitive detector is a synchronous detector.
Claim 10
Dependent Claim
25 words
An accelerometer according to claim 1, wherein the two torquer coils are mounted on the stator equidistant from the axis of rotation of the rotor.
Claim 11
Dependent Claim
29 words
An accelerometer according to claim 9, including a third torquer coil mounted on the stator, the two first mentioned torquer coils being mounted equidistant from the third torquer coil.
Claim 12
Dependent Claim
48 words
An accelerometer according to claim 10, wherein the torquer includes an E-shaped ferromagnetic core having two outer limbs and a central limb, the two first mentioned torquer coils being mounted on the outer limbs and the third torquer coil being mounted on the central limb of the core.
Claim 13
Dependent Claim
21 words
An accelerometer according to claim 1, wherein the torquer coils are connected in a long-tailed pair with a constant current circuit.
Claim 14
Dependent Claim
20 words
An accelerometer according to claim 1, in which the rotor is supported in the stator by means of air bearings.
References Cited (Backward Citations)
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US2942476A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-22 | 1977-04-23 | 1977-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-22 | 1981-04-23 | 1981-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-22 | 1985-04-23 | 1985-10-23 | $7700.00 | Window Closed / Lapsed |