Marine propulsion – Screw propeller – Having means to control flow around propeller
Reexamination Certificate
2001-01-25
2002-10-08
Swinehart, Ed (Department: 3617)
Marine propulsion
Screw propeller
Having means to control flow around propeller
Reexamination Certificate
active
06461206
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of water craft, namely to the design of rudders used for contributing to directional control of water craft. This invention, in particular, relates to a self compensating mechanism for automatically adjusting/retracting a portion of a rudder in response to impacts during maneuvering of the boat.
BACKGROUND OF THE INVENTION
The draft of boats are dictated by hull design features. In conventional construction, the drive gear is suspended below the hull. So the overall draft of a boat normally includes the distance from the waterline to the keel plus the space required by the drive gear. The rudder remains the conventional device for providing directional control under way in standard boat designs. As such, the rudder must be immersed in the water and have water flow across the control surface. However, the rudder increases the draft of the boat and increases drag. Typically, at least a portion of a rudder forms the lowermost point of the draft. A sudden impact to a rigid rudder may damage the directional control of the craft and possibly render the boat unseaworthy.
Water craft that operate in coastal or inland water ways are especially prone to rudder damage due to shallow water operation. In this area of operation, contact with the bottom of the waterway is always a possibility. Further, debris in the water poses a hazard for any water craft, regardless of the speed of the boat or depth of the water. The force of impact with such obstacles may irreparably damage the rudder and possibly render the vessel uncontrollable and unseaworthy.
In certain specialized hull designs having extremely shallow draft, the drive gear is located in a tunnel formed in the bottom of the boat. In these craft, the drive gear may be partially below the plane of the keel, on the same plane as the keel or even above the plane of the keel. Included in this specialized class are boats designed for high speeds with super cavitating propeller(s) such as those disclosed in U.S. Pat. No. 4,689,026 and U.S. Pat. No. 6,045,420; the contents of which are incorporated herein by reference. At high speed, the changing water conditions may result in sudden impacts on the rudder.
Thus, what is lacking in the art is a teaching of a rudder that will pivot or tilt to reduce drag and draft to compensate for various impacts while underway and automatically return to its original position.
SUMMARY OF THE INVENTION
A rudder for a water craft constructed to automatically compensate for impact on the rudder while the craft is maneuvering. The lower portion of the rudder is mounted to an upper portion by a pin. The lower portion can pivot about the pin to reduce drag and draft. The lower portion is spring loaded to return to the original position after impact.
Accordingly, it is an objective of the instant invention to provide a rudder that can compensate for sudden impacts during maneuvering without losing directional control.
It is a further objective of the instant invention to provide a two part rudder in which the lower portion is foldable into the upper portion to reduce draft.
It is yet another objective of the instant invention to provide a rudder which will automatically return the lower portion to its original position upon release of resistence.
It is a still further objective of the invention to provide a rudder in which the upper portion and lower portion are spring loaded in the original position and the resilience of the spring returns the lower portion to the original position when it is displaced by the force of an impact.
Other objectives and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof.
REFERENCES:
patent: 3422788 (1969-01-01), Horan, Jr.
patent: 3976026 (1976-08-01), Eastling
patent: 4689026 (1987-08-01), Small
patent: 5387141 (1995-02-01), Toyohara et al.
patent: 5437568 (1995-08-01), Kobayashi
patent: 6045420 (2000-04-01), Small et al.
Gruenwald David
Small Mark S.
McHale & Slavin
Power Vent Technologies, Inc.
Swinehart Ed
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