US3898744A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Constant precessed gyrocompass
Assignee: United States Department of the Army
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Filing: 1974-02-12
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Granted: 1975-08-12
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Expires: 1994-02-12
Abstract
Abstract A gyrocompass using an integrating gyro mounted on a platform rotating in a plane to which a local earth gravity vector is normal. The platform is rotated about an axis coincident with the output axis of the gyro with the spin axis and input axis in a plane parallel to the platform. The gyro is supported on the platform by an air bearing. As the platform rotates, an output is produced by the incipient relative motion of the gyro. This output is amplified and used to torque the gyro housing toward a null position with respect to the platform. The gyro is mechanically decoupled from the platform, but is constrained by the torquer to rotate with the platform. The rotation of the earth causes an output rotational tendency of the gyro, with the direction of the opposing or constraining torque dependent on the direction of the spin axis of the gyro. The average value of this torque is zero. The amount by which the average measured torque varies from zero is the measure of the bias torque resulting from friction, mass unbalance, etc. This device determines the true zero cross-over points of the torque. From these points a northsouth line can be established.
Inventors
- 👤 James V Johnston
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:02
CPC Classifications
G; G01; G01C; G01C19/00; G01C19/02; G01C19/34; G01C19/38; Y; Y10; Y10T; Y10T74/00; Y10T74/12; Y10T74/1229
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
228 words
A constant precessed gyrocompass including: a level platform about a first axis; an integrating gyro mounted on said platform and including an outer housing fixed to said platform and an inner cylinder carrying the rotor of said gyro, said inner cylinder, rotatable with respect to said outer housing parallel to the plane of said platform, said gyro having an input axis, and an output axis, and a spin axis of said rotor, with said spin axis and said input axis in a plane parallel to said platform, and said output axis coincident with said first axis; means for providing output pulses when said gyro inner cylinder exerts a torque about its output axis, with the polarity of said pulses dependent on the direction of said torque; means for rotating said inner cylinder of said gyro with respect to said outer housing in response to said output pulses, whereby said inner cylinder of said gyro tends to maintain a predetermined angular relationship with said outer housing and said platform as the platform rotates; adjustable means for providing a position pulse for each revolution of said platform; means connected both to said means for providing output pulses and to said adjustable means, for providing an indication of the angular displacement of said adjustment means from the north-south plane with respect to said first axis when it provides its position pulse.
Claim 2
Dependent Claim
228 words
A constant precessed gyrocompass including: a level platform about a first axis; an integrating gyro mounted on said platform and including an outer housing fixed to said platform and an inner cylinder carrying the rotor of said gyro, said inner cylinder, rotatable with respect to said outer housing parallel to the plane of said platform, said gyro having an input axis, and an output axis, and a spin axis of said rotor, with said spin axis and said input axis in a plane parallel to said platform, and said output axis coincident with said first axis; means for providing output pulses when said gyro inner cylinder exerts a torque about its output axis, with the polarity of said pulses dependent on the direction of said torque; means for rotating said inner cylinder of said gyro with respect to said outer housing in response to said output pulses, whereby said inner cylinder of said gyro tends to maintain a predetermined angular relationship with said outer housing and said platform as the platform rotates; adjustable means for providing a position pulse for each revolution of said platform; means connected both to said means for providing output pulses and to said adjustable means, for providing an indication of the angular displacement of said adjustment means from the north-south plane with respect to said first axis when it provides its position pulse.
Claim 3
Dependent Claim
61 words
The gyrocompass as defined in claim 1 wherein a number of positive output pulses are followed by an equal number of negative pulses for each revolution of said gyro about said first axis, and wherein said means connected includes means for counting the number of positive pulses from the time of said positive pulse to the start of said negative pulses.
Claim 4
Dependent Claim
168 words
The gyrocompass as defined in claim 2 wherein said means connected includes means for sensing positive output pulses and means for sensing negative output pulses with each means for sensing having an input connected to said means for providing and each further including an output; gate means having a signal input, a signal output, and control inputs, with the output of said means for sensing positive pulses connected to said signal input, and said adjustable means for providing connected to a first control input; an accumulatoR having a signal input connected to the signal output of said gate; a signal output, and a control input; a preset-reset having inputs and outputs; a printer having a control input and a signal input; said outputs of said means for sensing negative and said gate connected to inputs of said preset-reset, and respective outputs of said preset connected to a second control input of said gate, to said control input of said accumulator, and to said control input of said printer.
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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) | 1978-08-11 | 1979-02-10 | 1979-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-11 | 1983-02-10 | 1983-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-11 | 1987-02-10 | 1987-08-12 | $7700.00 | Window Closed / Lapsed |