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US3928754A Expired / Lapsed US ⏱️ 0.0 years remaining

Device for calculating the resonant rolling period of a ship

Assignee: Individual
•
Filing: 1974-05-03
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Granted: 1975-12-23
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Expires: 1994-05-03
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Abstract

Abstract A computing device that measures the time between consecutive signals coming from a rolling time gauge that gives a signal every time the ship starts rolling from one direction. The time measured is the time of one single complete period of rolling. Every period of rolling is thereby measured individually. These measurements are collected in an electronic memory. Every single rolling time is different from the other and they are statistically spread over an interval. The spreading depends, among other things, on influence of the sea and the yaws. When a certain number of rolling times are stored in the memory, the computing device carries out a maximum calculation. This means that the computing device calculates and presents the rolling time that is most common. This is the period of resonance of the ship as a swinging system, and it is defined as the rolling time of the ship under actual conditions. The gauge and the computing device are working continually, thereby showing changes of the stability condition depending, for example, on an icy superstructure and changed conditions in the bunker. When the rolling time is known and the draught of the ship has been determined, the stability condition can be read on a certain diagram, thus enabling the officer at watch always to be in possession of accurate information of the seaworthiness of his ship. Since a recording equipment can be connected to the abovedescribed device, the stability condition can be documented during the whole trip which can be important, e.g. when carrying fruit and other fragile cargo.

Inventors

  • 👤 Herman Allan Friedrich Edlund

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-29 18:52
CPC Classifications
G; G05; G05D; G05D1/00; G05D1/08; G05D1/0875

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 149 words
A device for ascertaining the most prevalent rolling period of a ship, including a pulse generator responsive to rolling to generate a train of pulses, each of which has a predetermined time relationship with the rolling motion in which it occurs, the interval between successive pulses representing the rolling period, a statistical memory having different storage locations corresponding respectively to different values of rolling period, a timer responsive to each new pulse from the pulse generator to start a new timing cycle and to enter a signal into the storage location corresponding to the duration of the period terminated by that pulse, an output scanner for scanning the storage locations to derive signals representing the number of entries in the different storage locations, and a maximum signal sensor responsive to the signals from the output scanner for ascertaining the storage location in which the most signals have been entered.
Claim 2
Independent Claim 149 words
A device for ascertaining the most prevalent rolling period of a ship, including a pulse generator responsive to rolling to generate a train of pulses, each of which has a predetermined time relationship with the rolling motion in which it occurs, the interval between successive pulses representing the rolling period, a statistical memory having different storage locations corresponding respectively to different values of rolling period, a timer responsive to each new pulse from the pulse generator to start a new timing cycle and to enter a signal into the storage location corresponding to the duration of the period terminated by that pulse, an output scanner for scanning the storage locations to derive signals representing the number of entries in the different storage locations, and a maximum signal sensor responsive to the signals from the output scanner for ascertaining the storage location in which the most signals have been entered.
Claim 3
Dependent Claim 113 words
A device in accordance with claim 1, in which the maximum signal sensor includes an integrator for generating a waveform representing the sum of the successive outputs of the scanned storage locations, each output corresponding to the number of signals entered in that storaGe location, a differentiating circuit for deriving a signal representing the time derivative of the integrator output, means responsive to the output of the differentiating circuit to sense a value thereof corresponding to the portion of the integrator output in which the maximum rate of increase occurs, and means for applying a signal representing the storage location corresponding to the said portion of the integrator output to an indicating apparatus.
Claim 4
Dependent Claim 36 words
A device in accordance with claim 1, including means responsive to the number of entries in a storage location reaching a predetermined maximum for subtracting an equal number of entries from each of the storage locations.
Claim 5
Dependent Claim 96 words
A device in accordance with claim 1, in which the timer is an electronic stepping switch which steps at predetermined intervals through a number of switch conditions, following initiation of the operation of the timer, the switch having a number of output conductors corresponding to respective switch conditions and connected to respective ones of the storage locations, the switch being so arranged that in response to a signal from the pulse generator a pulse representing the existing switch condition is applied over the corresponding output conductor to the corresponding storage location and the switch is reset.
Claim 6
Dependent Claim 134 words
A device in accordance with claim 1, in which the pulse generator comprises a flywheel fixed to a shaft, an elongated member mounted at one of its ends on the shaft through a bearing which has substantial friction, the other of its ends being free, and two stop members mounted on opposite sides of the free end of the elongated member so as to be contacted by the elongated member in response to relative rotation between the flywheel and the stop members, one of the stop members including means for transmitting an electric signal in response to contact with the elongated member, whereby when the device is mounted on a ship with the shaft extending in the longitudinal direction of the ship, electric signals are generated in response to rolling motion of the ship.

References Cited (Backward Citations)

US2910233A Cited
US3559610A Cited
US3516377A Cited
US3665168A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1978-12-22 1979-06-23 1979-12-23 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1982-12-22 1983-06-23 1983-12-23 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1986-12-22 1987-06-23 1987-12-23 $7700.00 Window Closed / Lapsed

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