US3738304A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ship stabilization apparatus
Assignee: National Research Development Corp UK
•
Filing: 1970-10-26
•
Granted: 1973-06-12
•
Expires: 1990-10-26
Abstract
Abstract The invention is concerned with an anti-roll stabilization system for ships of the kind in which a fin, in operation, protrudes from the ship below the water-line and is angularly displaced about its axis by power means in response to a fin control signal, wherein a primary signal produced by a sensing device responsive to rolling motion of the ship is processed by a configuration of operational amplifiers programmed to produce a fin control signal having the required phase advance, gain/frequency characteristic to position the fin to reduce the rolling moment of the ship.
Inventors
- 👤 A Duberley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:55
CPC Classifications
B; B63; B63B; B63B39/00; B63B39/06; G; G05; G05D; G05D1/00; G05D1/08; G05D1/0875
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
123 words
An anti-roll stabilization system for ships of the type in which a fin, in operation, protrudes from the ship below the water-line and is angularly displaced in response to a fin control signal comprising: means for detecting the ship roll angle and producing an electrical roll angle signal which varies as a function of roll angle, circuit means for receiving said roll angle signal and having a second order lead/lag transfer function for producing an electrical fin control signal, means for detecting ship speed and producing an electrical ship speed signal which varies as a function of the inverse square of the ship speed and means for receiving and multiplying said fin control and ship speed signals to produce a further control signal.
Claim 2
Dependent Claim
123 words
An anti-roll stabilization system for ships of the type in which a fin, in operation, protrudes from the ship below the water-line and is angularly displaced in response to a fin control signal comprising: means for detecting the ship roll angle and producing an electrical roll angle signal which varies as a function of roll angle, circuit means for receiving said roll angle signal and having a second order lead/lag transfer function for producing an electrical fin control signal, means for detecting ship speed and producing an electrical ship speed signal which varies as a function of the inverse square of the ship speed and means for receiving and multiplying said fin control and ship speed signals to produce a further control signal.
Claim 3
Dependent Claim
29 words
An anti-roll stabilization system according to claim 1 in which the gain of the fin control signal is varied inversely as the square of the speed of the ship.
Claim 4
Dependent Claim
51 words
An anti-roll stabilization system according to claim 2 in which a signal inversely proportional to the square of the speed of the ship is produced in a configuration of operational amplifiers and is then fed into a multiplier together with the fin control signal wherein the two signals are multiplied together.
Claim 5
Dependent Claim
55 words
An anti-roll stabilization system according to claim 3 in which, in place of the signal inversely proportional to the square of the speed of the ship, a signal is derived from one or more preset potentiometers the voltage across each of which is adjusted to give a signal corresponding to a range of ships'' speed.
Claim 6
Dependent Claim
30 words
An anti-roll stabilization system according to claim 3 wherein the input stage of the configuration of operational amplifiers is designed to saturate when the primary signal exceeds some specified amplitude.
Claim 7
Dependent Claim
31 words
An anti-roll stabilization system according to claim 5 wherein the output voltage of some at least of the operational amplifiers is limited by using pairs of diodes in the feedback path.
Claim 8
Dependent Claim
67 words
An anti-roll stabilization system according to claim 3 in which compensation is made for the natural list of the ship about its roll axis by subtracting within a configuration of operational amplifiers from the roll angle signal produced therein a signal produced by averaging the roll angle signal in an operational amplifier having a time constant which is large compared with the natural period of the ship.
Claim 9
Dependent Claim
49 words
An anti-roll stabilization system according to claim 3 in which the operating mode of the operational amplifiers normally forming the lead/lag network in the configuration of operational amplifiers may be switched to form a sine wave generator thereby producing a fin control signal producing forced rolling of the ship.
References Cited (Backward Citations)
US2890673A
Cited
US2946943A
Cited
US3020869A
Cited
US3227935A
Cited
US3465276A
Cited
US3557734A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-11 | 1976-12-11 | 1977-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-11 | 1980-12-11 | 1981-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-11 | 1984-12-11 | 1985-06-12 | $7700.00 | Window Closed / Lapsed |