Patent US3800003A successfully refreshed from Google Patents.
US4445371A
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Gravity meter and method
Assignee: BP Corp North America Inc
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Filing: 1982-04-30
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Granted: 1984-05-01
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Expires: 2002-04-30
Abstract
Abstract Measurements of the gravitational field are made by generating a frequency representative of the gravitational field. In one aspect, the frequency is generated by oscillations in a magnetic vibrator formed by magnets having vertically opposed magnetic poles.
Inventors
- 👤 Theodore V. Lautzenhiser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 06:11
CPC Classifications
G; G01; G01V; G01V7/00; Y; Y10; Y10S; Y10S73/00; Y10S73/01
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
135 words
Apparatus for determining the magnitude of the accleration of gravity at a location comprising: a magnetic shield; a temperature controlled housing; a first magnet having a generally dipolar magnetic field; a second magnet having a generally dipolar magnetic field; support means for vertically supporting in a substantially vertical gravity field within the temperature controlled housing and within the magnetic shield the first magnet and the second magnet with opposed magnetic poles so as to form a magnetic vibrator; first means for maintaining oscillation at a natural frequency of the magnetic vibrator formed by the first magnet and the second magnet in the substantially vertical gravity field, the natural frequency being representative of the acceleration of gravity at a location; and second means responsive to said oscillation for generating a signal correlated to the natural frequency.
Claim 2
Dependent Claim
135 words
Apparatus for determining the magnitude of the accleration of gravity at a location comprising: a magnetic shield; a temperature controlled housing; a first magnet having a generally dipolar magnetic field; a second magnet having a generally dipolar magnetic field; support means for vertically supporting in a substantially vertical gravity field within the temperature controlled housing and within the magnetic shield the first magnet and the second magnet with opposed magnetic poles so as to form a magnetic vibrator; first means for maintaining oscillation at a natural frequency of the magnetic vibrator formed by the first magnet and the second magnet in the substantially vertical gravity field, the natural frequency being representative of the acceleration of gravity at a location; and second means responsive to said oscillation for generating a signal correlated to the natural frequency.
Claim 3
Dependent Claim
82 words
Apparatus as in claim 1 wherein: the opposed magnetic poles effects a variable space between a pole of the first magnet and a corresponding pole of the second magnet; and wherein the first means further comprises: a coil mounted in the variable space; oscillator means electrically connected to the coil for maintaining the magnetic vibrator in oscillation at the natural frequency; and wherein the second means comprises counter means having an electrical input from the oscillator means for determining the natural frequency.
Claim 4
Dependent Claim
23 words
Apparatus as in claim 2 wherein: the first means further comprises means for selectively damping and enhancing oscillation of the oscillating magnetic vibrator.
Claim 5
Dependent Claim
22 words
Apparatus as in claim 2 wherein: the first magnet and the second magnet are magnets having a low temperature coefficient of expansion.
Claim 6
Dependent Claim
18 words
Apparatus as in claim 4 wherein: the magnets have substantially zero coefficient of expansion to over 200° C.
Claim 7
Dependent Claim
26 words
Apparatus as in claim 1 wherein: the support means permits oscillation with only one degree of freedom in the direction of the substantially vertical gravity field.
Claim 8
Dependent Claim
27 words
Apparatus as in claim 6 wherein: the first means and the second means are mounted in a gravity sonde adapted to be used in a remote location.
Claim 9
Dependent Claim
45 words
Apparatus as in claim 2 wherein: the first magnet and the second magnet are disk magnets each having a vertical axis aligned with the vertical gravity field; and the coil has a vertical axis substantially coaxial with the vertical axis of the vertical gravity field.
Claim 10
Dependent Claim
58 words
Method for determining the magnitude of the acceleration of gravity at a location comprising: maintaining oscillation at a natural frequency of a magnetic vibrator formed by magnets having vertically opposed magnetic poles in a substantially vertical gravity field, the natural frequency being representative of the acceleration of gravity at a location; generating a signal correlated to said oscillation.
Claim 11
Dependent Claim
58 words
Method for determining the magnitude of the acceleration of gravity at a location comprising: maintaining oscillation at a natural frequency of a magnetic vibrator formed by magnets having vertically opposed magnetic poles in a substantially vertical gravity field, the natural frequency being representative of the acceleration of gravity at a location; generating a signal correlated to said oscillation.
Claim 12
Dependent Claim
33 words
Method as in claim 9 comprising: damping oscillation of the magnetic vibrator; thereafter enhancing and maintaining oscillation of the magnetic vibrator at the natural frequency; and determining the natural frequency from said signal.
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) | 1987-05-01 | 1987-10-31 | 1988-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-01 | 1991-10-31 | 1992-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-01 | 1995-10-31 | 1996-05-01 | $7700.00 | Window Closed / Lapsed |