US3677082A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Knotmeter for small craft
Assignee: United States Department of the Navy
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Filing: 1970-11-30
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Granted: 1972-07-18
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Expires: 1990-11-30
Abstract
Abstract A regulated source of power is used to set up a magnetic field in the water around a rodmeter. The output is fed to an amplifier which in turn is connected to a ring demodulator which produces a pulsating D.C. voltage. A capacitor smoothes the D.C. output and feeds it to an integrating digital voltmeter to provide a display which is proportional to the average speed of the craft through the water.
Inventors
- 👤 George B Springston Jr
- 👤 Samuel L Thomas
- 👤 Fred B Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:25
CPC Classifications
G; G01; G01P; G01P5/00; G01P5/08
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
207 words
A device for measuring the speed of a ship through water, comprising: an A.C. source; a regulator connected to said A.C. source; said regulator including a feedback network having a voltage variable resistor, said voltage variable resistor being responsive to the output of said amplifier for controlling the gain of said amplifier and holding it to a regulated value; means for generating a magnetic field, connected to the output of said amplifier, for generating a magnetic field in the water and a voltage corresponding to said magnetic field and responsive to the speed of the field through the water; a sensor within said magnetic field for detecting said voltage; amplifying means connected to said sensor for amplifying said sensed signals; a phasing network connected to said A.C. source for adjusting a phase of said A.C. source to be in phase with the voltage from the sensor; a ring demodulator; said phasing network having its output connected to the ring demodulator and injecting a carrier into said ring demodulator for demodulating said sensor signal; said sensor amplifier output being connected to the input of said demodulator; said ring demodulator rectifying the sensor signal and producing an output indicative of the speed of the magnetic field through the water.
Claim 2
Independent Claim
207 words
A device for measuring the speed of a ship through water, comprising: an A.C. source; a regulator connected to said A.C. source; said regulator including a feedback network having a voltage variable resistor, said voltage variable resistor being responsive to the output of said amplifier for controlling the gain of said amplifier and holding it to a regulated value; means for generating a magnetic field, connected to the output of said amplifier, for generating a magnetic field in the water and a voltage corresponding to said magnetic field and responsive to the speed of the field through the water; a sensor within said magnetic field for detecting said voltage; amplifying means connected to said sensor for amplifying said sensed signals; a phasing network connected to said A.C. source for adjusting a phase of said A.C. source to be in phase with the voltage from the sensor; a ring demodulator; said phasing network having its output connected to the ring demodulator and injecting a carrier into said ring demodulator for demodulating said sensor signal; said sensor amplifier output being connected to the input of said demodulator; said ring demodulator rectifying the sensor signal and producing an output indicative of the speed of the magnetic field through the water.
Claim 3
Dependent Claim
27 words
The device of claim 1 wherein said sensor means are pick-up buttons within said magnetic field for sensing the voltage and producing a signal from said voltage.
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) | 1975-07-18 | 1976-01-17 | 1976-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-18 | 1980-01-17 | 1980-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-18 | 1984-01-17 | 1984-07-18 | $7700.00 | Window Closed / Lapsed |