US3676648A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Turn heel limiting circuit
Assignee: Litton Marine Systems Inc
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Filing: 1971-05-04
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Granted: 1972-07-11
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Expires: 1991-05-04
Abstract
Abstract Heeling of a ship during a turning maneuver is restricted to a safe value in accordance with the ship''s speed and heading rate. A limit computer accepts a signal indicative of the ship''s speed and provides a rudder angle limiting signal which is a function of the reciprocal of the square of the ship''s speed. The polarity of a second signal representing the rate-of-change of the ship''s heading is used to limit only those rudder angles that would decrease the turning radius. Rudder order command signals are ordinarily applied to the ship''s steering mechanism without alterations. A command signal calling for an excessive rudder angle, however, is limited to the value of the rudder angle limiting signal.
Inventors
- 👤 Charles R Wesner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 07:30
CPC Classifications
G; G05; G05D; G05D1/00; G05D1/02; G05D1/0206
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
118 words
Apparatus for limiting an output voltage to the value of a threshold voltage comprising first amplifying means for providing an output voltage in response to a received signal, first and second limiter amplifiers, means to establish positive and negative threshold voltages, said first and second limiter amplifiers being connected to receive said positive and negative threshold voltages respectively, said limiter amplifiers being further connected to compare the output signal from said first amplifying means with the appropriate threshold voltage, first and second diode means connected to clamp the input of said first amplifying means to the output of said first and second limiter amplifiers respectively whenever the output of said first amplifying means exceeds the corresponding threshold voltage.
Claim 2
Dependent Claim
118 words
Apparatus for limiting an output voltage to the value of a threshold voltage comprising first amplifying means for providing an output voltage in response to a received signal, first and second limiter amplifiers, means to establish positive and negative threshold voltages, said first and second limiter amplifiers being connected to receive said positive and negative threshold voltages respectively, said limiter amplifiers being further connected to compare the output signal from said first amplifying means with the appropriate threshold voltage, first and second diode means connected to clamp the input of said first amplifying means to the output of said first and second limiter amplifiers respectively whenever the output of said first amplifying means exceeds the corresponding threshold voltage.
Claim 3
Dependent Claim
78 words
The apparatus of claim 1 wherein the first diode means is connected between the output of said first limiter amplifier and the input of said first amplifying means and oriented to pass current from said limiter to said amplifying means and wherein said second diode means is connected between the output of said second limiter amplifier and the input of said first amplifying means and oriented to pass current from the first amplifying means to the limiter amplifier.
Claim 4
Dependent Claim
33 words
The apparatus of claim 2 wherein the output signal is a rudder order signal for setting the rudder angle of a marine craft and the received signals are functions of the craft heading.
Claim 5
Dependent Claim
114 words
The apparatus of claim 3 wherein the means to establish positive and negative thresholds is a rudder limit computer, said rudder limit computer including means to receive signals indicative of the craft''s speed and signals indicative of the rate-of-change of heading of the craft, said rudder limit computer including means to provide a first threshold signal having a magnitude that is a function of the reciprocal of a square of the craft''s speed, and means to invert the threshold voltage, said rudder limit computer further including means responsive to the polarity of said rate-of-change of heading signal for coupling the direct or the inverted threshold signal to said first or second limiter amplifier respectively.
Claim 6
Dependent Claim
81 words
The apparatus of claim 4 wherein the means to provide the first threshold signal includes a squaring circuit connected to receive a signal representative of the craft speed and a divider circuit, said divider circuit being connected to receive a d.c. voltage representative of the selected maximum heel angle and a signal from said squaring circuit, said divider circuit being arranged to provide an output signal representative of the ratio of said d.c. voltage to the signal from said squaring circuit.
Claim 7
Dependent Claim
88 words
The apparatus of claim 5 wherein the means responsive to the polarity of the rate-of-change of heading includes means for coupling said direct and inverted threshold signals through individual series resistors to said first and second limiter amplifiers respectively, first and second switching means for optionally connecting the output of individuaL series resistors to positive and negative voltage sources respectively, said voltage sources providing voltages representative of the maximum rudder angle, said switches being closed in response to negative and positive polarities of rate-of-change of heading signals respectively.
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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) | 1975-07-11 | 1976-01-10 | 1976-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-11 | 1980-01-10 | 1980-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-11 | 1984-01-10 | 1984-07-11 | $7700.00 | Window Closed / Lapsed |