US4061040A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for measuring rotation rates with acoustic waves
Assignee: United States Department of the Navy
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Filing: 1976-07-02
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Granted: 1977-12-06
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Expires: 1996-07-02
Abstract
Abstract A measuring apparatus for determining the rotational velocity of a solid erical or cylindrical object by propagating an acoustic wave through the object. The inward face of the surface of the object is used to reflect the wave, thereby causing it to make multiple transits through the object. Multiple transits provide a large time factor which allows the apparatus to achieve a high degree of sensitivity in measuring small rate changes and low rotation rates.
Inventors
- 👤 Herbert J. Shaw
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:49
CPC Classifications
G; G01; G01P; G01P3/00; G01P3/42; G01P3/44
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
161 words
An apparatus for measuring the rotation rate of a spherical object of an isotropic material about axes passing through its center comprising: a. means for exciting an acoustic wave at a first point on the surface of said object; b. means for sensing the arrival of said acoustic wave on the surface of said object at a second point diametrically opposite to said exciting means, said exciting means and said sensing means being spaced apart from said object; c. means for measuring the transit time required for said acoustic wave excited at said first point to propagate through said object to said second point; and d. means for computing said rotation rate as a function of said transit time according to the formula θ = (2/T) cos.sup.-1 (vT/d) where θ is said rotation rate, T is said transit time, v is the acoustic velocity of propagation of said acoustic wave through said object, and d is the diameter of said object.
Claim 2
Independent Claim
161 words
An apparatus for measuring the rotation rate of a spherical object of an isotropic material about axes passing through its center comprising: a. means for exciting an acoustic wave at a first point on the surface of said object; b. means for sensing the arrival of said acoustic wave on the surface of said object at a second point diametrically opposite to said exciting means, said exciting means and said sensing means being spaced apart from said object; c. means for measuring the transit time required for said acoustic wave excited at said first point to propagate through said object to said second point; and d. means for computing said rotation rate as a function of said transit time according to the formula θ = (2/T) cos.sup.-1 (vT/d) where θ is said rotation rate, T is said transit time, v is the acoustic velocity of propagation of said acoustic wave through said object, and d is the diameter of said object.
Claim 3
Independent Claim
203 words
An apparatus for measuring the rotation rate of a spherical object of an isotropic material about axes passing through its center comprising: a. means for exciting an acoustic wave at a first point on the surface of said object; b. means for sensing the arrival of said acoustic wave on the surface of said object at a second point fixed relative to said exciting means, said exciting means and sensing means being spaced apart from said object; c. means for measuring the transit time required for said acoustic wave excited at said first point to propagate through said object ot said second point; d. means for computing said rotation rate as a function of said transit time; and a fluid surrounding said object, the acoustic impedance of said isotropic material being sufficiently greater than the acoustic impedance of said fluid to enable said acoustic wave to be inwardly reflected upon its impingement upon the inner surface of said object such that said acoustic wave is multiply reflected within said object such that said rotation rate of said object as computed by said computing means is a function of the transit time required by said acoustic wave to propagate through said object N times.
Claim 4
Independent Claim
203 words
An apparatus for measuring the rotation rate of a spherical object of an isotropic material about axes passing through its center comprising: a. means for exciting an acoustic wave at a first point on the surface of said object; b. means for sensing the arrival of said acoustic wave on the surface of said object at a second point fixed relative to said exciting means, said exciting means and sensing means being spaced apart from said object; c. means for measuring the transit time required for said acoustic wave excited at said first point to propagate through said object ot said second point; d. means for computing said rotation rate as a function of said transit time; and a fluid surrounding said object, the acoustic impedance of said isotropic material being sufficiently greater than the acoustic impedance of said fluid to enable said acoustic wave to be inwardly reflected upon its impingement upon the inner surface of said object such that said acoustic wave is multiply reflected within said object such that said rotation rate of said object as computed by said computing means is a function of the transit time required by said acoustic wave to propagate through said object N times.
Claim 5
Dependent Claim
43 words
The rotation rate measuring apparatus recited in claim 2 including a housing radially encompassing and spaced apart from the periphery of said spherical object with said exciting means and said sensing means being located at first and second positions, respectively, in said housing.
Claim 6
Dependent Claim
92 words
The rotation rate measuring apparatus recited in claim 3 wherein: a. said spherical object has a surface composed of a piezoelectric material; b. said exciting means includes an RF voltage generator, a pulser, and at least one input electrode; c. said RF voltage generator being electrically connected to said pulser; d. said pulser being electrically connected to said at least one input electrode in a manner which enables RF electric fields to be generated at the surface of said spherical object; and e. said sensing means includes at least one output electrode.
Claim 7
Dependent Claim
42 words
The rotation rate measuring apparatus recited in claim 4 wherein a. the output of said RF voltage generator is applied to the input of said measuring means; and b. said at least one output electrode is electrically connected to said measuring means.
Claim 8
Dependent Claim
44 words
The rotation rate measuring apparatus as recited in claim 5 wherein said measuring means is a phase detector which measures said transit time by comparing the instantaneous RF phase of said RF voltage generator with the signal from said at least one output electrode.
Claim 9
Dependent Claim
93 words
The rotation rate measuring apparatus recited in claim 3 wherein: a. said spherical object has a surface composed of a conductive material; b. said exciting means includes an RF voltage generator, a pulser, and at least one input conductive coil; c. said RF voltage generator being electrically connected to said pulser; d. said pulser being electrically connected to said at least one input coil in a manner which enables Eddy currents to be generated on the surface of said spherical object; and e. said sensing means includes at least one output conductive coil.
Claim 10
Dependent Claim
42 words
The rotation rate measuring apparatus recited in claim 7 wherein: a. the output of said RF voltage generator is applied to the input of said measuring means; and b. said at least one output coil is electrically connected to said measuring means.
References Cited (Backward Citations)
US3232120A
Cited
US3905235A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-12-05 | 1981-06-06 | 1981-12-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-12-05 | 1985-06-06 | 1985-12-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-12-05 | 1989-06-06 | 1989-12-06 | $7700.00 | Window Closed / Lapsed |