Ships – Steering mechanism – Rudders
Reexamination Certificate
1999-04-27
2001-01-30
Avila, Stephen (Department: 3617)
Ships
Steering mechanism
Rudders
C114S1440RE
Reexamination Certificate
active
06178907
ABSTRACT:
BACKGROUND OF THE INVENTION
I. Field of the Invention
The present invention relates generally to steering systems for watercraft, and more particularly to the definition and control of predetermined rudder configurations used in maneuvering watercraft.
II. Description of Prior Art
Flanking rudders, as the term is used herein, are rudders which are located forward of the main thrust producing device(s), typically propellers or “screws,” for a particular watercraft. Whether the watercraft includes a single screw or several, it would be common to employ a flanking rudder directly in front of each of the screws. The basic concept of flanking rudders has been understood at least as early as the 1800's when such rudders were used in connection with paddle wheeled steamboats. At the present time, flanking rudders are commonly installed on towboats that push barges on the inland river systems of North and South America. The primary function of flanking rudders is to provide the watercraft with a means of steering as the watercraft travels in reverse. For example, as the screws or other thrust-producing device directs reverse thrust toward the front of the watercraft, the flanking rudders are employed in tandem to steer the watercraft in the desired direction. This is particularly useful in the case of utility boats, such as tug boats, which routinely change from forward and reverse thrust in assisting larger ships, such as oil tankers and cargo ships, into a docking position in a river; with towboats that push barges on inland rivers and coastal waters; and, seagoing vessels.
Although the presence of flanking rudders operating in tandem mode is a significant enhancement to the maneuverability of any of these types of vessels, there are situations where greater control over the operation of the flanking rudders would be highly desirable. For example, in many instances, tug boats must attach to one side of a ship having a deeper draft than the tug boat. When reverse thrust is applied over conventional flanking rudders to pull the larger ship, the thrust is necessarily directed against the hull of the larger ship. The undesirable effect is for the stem of the tug boat to be urged away from the ship, thus losing some control over the larger ship. While lines can be used to tie the tug boat to the larger ship, this is an imperfect solution. Ideally, the flanking rudders would be subject to independent control to allow the innermost flanking rudder to remain parallel to the keel of the ship, while the outermost flanking rudder is used to direct thrust in the desired direction. Also, once independent control of the flanking rudders is implemented, it would be quite useful to operate the flanking rudders in a converging or diverging mode, such that the flanking rudders can be placed in a flared position for braking when the vessel is moving forward or moving astern, and for redirection of thrust. Consequently, the present invention is provided as a solution to the foregoing problems by illustrating a novel flanking rudder steering system capable of being controlled in a variety of predefined operational modes by one or more controlling devices.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to provide a steering system for watercraft which employs flanking rudders for use in connection with reverse thrust.
It is also an object of this invention to provide a steering system for watercraft which allows independent control of the flanking rudders.
It is a further object of this invention to provide a steering system for watercraft which permits the selection of one or more predetermined rudder control configurations useful to operators in the maneuverability of the watercraft.
Yet another object of this invention is to provide a steering system for watercraft which employs flanking rudders and an accompanying control system which be retrofitted to existing watercraft.
These and other objects and advantages of the present invention will no doubt become apparent to those skilled in the art after having read the following description of the preferred embodiment which are contained in and illustrated by the various drawing figures.
Therefore, in a preferred embodiment, a flanking rudder system is provided for watercraft having a hull and first and second thrust producing devices capable of providing forward or reverse thrust relative to said hull, wherein said first and second thrust producing devices provide thrust along first and second thrust axes, respectively, comprising a first rudder assembly positioned forward of said first thrust producing device, wherein said first rudder assembly is pivotally connected beneath said hull; a second rudder assembly positioned forward of said second thrust producing device, wherein said second rudder assembly is pivotally connected beneath said hull; first actuation means operatively connected to said first rudder assembly for actuating a change in the rotational position of said first rudder assembly; second actuation means operatively connected to said second rudder assembly for actuating a change in the rotational position of said second rudder assembly; and control means operatively connected to said first and second actuation means for controlling the rotational position of said first and second rudder assemblies independent of one another, said control means further including selection means for selectively defining the operation of said first rudder assembly or said second rudder assembly in one or more predetermined configurations. While it is generally contemplated that the first and second thrust producing devices are propellers, it is also possible that the thrust may be produced by other means.
In one embodiment, said first rudder assembly and said second rudder assembly each include a single rudder. However, in an alternate embodiment, said first rudder assembly and said second rudder assembly each include a pair of rudders connected to said first actuation means and said second actuation means, respectively, so as to enable said pair of rudders to remain parallel at all rotational positions. Although not specifically required, said first actuation means and said second actuation means each comprise an electro-hydraulic mechanical linkage assembly.
The control means comprises at least one control lever operatively connected to said first actuation means and said second actuation means, respectively, to control the rotational position of either said first rudder assembly or said second rudder assembly. Furthermore, the selection means comprises a console adjacent to said control means, wherein said console includes an electrical switching device having a plurality of selectable settings corresponding to said predetermined configurations.
One of said predetermined configurations defines said first rudder assembly and said second rudder assembly to operate in tandem, such that operation of said control means causes said first and second rudder assemblies to remain parallel to one another. Another of said predetermined configurations defines said first rudder assembly to remain fixed in a rotational position parallel to said first thrust axis of said first thrust producing device, and wherein the rotational position of said second rudder assembly is controlled by said control means. Another of said predetermined configurations defines said second rudder assembly to remain fixed in a rotational position parallel to said second thrust axis of said second thrust producing device, and wherein the rotational position of said first rudder assembly is controlled by said control means. Yet another of said predetermined configurations defines said first rudder assembly and said second rudder assembly to operate opposed to one another, wherein the rotational position of said first rudder assembly and said second rudder assembly are controlled by said control means.
Also, in a preferred embodiment, a method is provided for steering a watercraft having a hull and first and second thrust producing devices capable of providing forward o
Hackney David C.
Shirah David C.
Avila Stephen
Delaune Warner J.
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