Marine propulsion – Screw propeller – Variable pitch
Reexamination Certificate
2000-08-04
2001-07-24
Avila, Stephen (Department: 3617)
Marine propulsion
Screw propeller
Variable pitch
C440S084000, C440S087000, C416S235000
Reexamination Certificate
active
06264512
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a control for a boat. More particularly this invention concerns a system for jointly controlling the engine throttle, the pitch of a variable-pitch propeller, and a clutch connecting the propeller to the engine.
BACKGROUND OF THE INVENTION
A lever-type control for a boat having a variable-pitch propeller is standard. As the lever is tipped forward, the propeller pitch is increased in a forward direction to move the boat forward, and when the lever is tipped backward the propeller-vane pitch is reversed to move the boat backward. In a central neutral position the propeller pitch is null so that, even if the propeller is rotating, the boat will not move. The lever is often associated with a throttle control that increases engine speed as pitch exceeds a certain level.
In small motor boats used for sport or fishing purposes and having a variable-pitch propeller it is normally only possible to increase the pitch in the forward direction; pitch settings for reverse are not available. A transmission and clutch are provided between the engine and the propeller for reversing it. Controlling such a system is fairly complex, in particular for starting which requires special settings so that engine does not have to start under load. Furthermore in many small-boat systems when the lever is in the central neutral position, the propeller continues to rotate, albeit at 0° pitch so that the boat does not move, but the rotating propeller still presents a hazard for swimmers who might want to board the boat over the stern.
OBJECTS OF THE INVENTION
It is therefore an object of the present invention to provide an improved control for a boat having a variable-pitch propeller connected via a clutch to a drive engine.
Another object is the provision of such an improved control for a boat drive which overcomes the above-given disadvantages, that is which allows easy control of the boat for forward and reverse movement, and easy and save starting of the engine.
SUMMARY OF THE INVENTION
A boat drive having a variable-speed engine connected through a clutch to a variable-pitch propeller has a control having according to the invention a housing and a guide on the housing defining a central crosswise track having a travel end and a start end, forward and backward travel tracks extending from the travel end, and a forward start track extending from the start end. A lever pivoted on the housing is movable in the tracks of the guide. A pitch controller connected to the propeller includes a position detector operable by the lever when in the travel end and travel tracks for increasing propeller pitch positively on movement of the lever forward from the travel end in the forward travel track and negatively on movement of the lever backward from the travel end in the backward track and for setting the propeller at 0° pitch when the lever is in the travel end. An engine controller connected to the engine and to the clutch includes a position detector operable by the lever when in the start track for opening the clutch and varying engine speed in accordance with movement of the lever along the start track.
Thus with this system when the lever is in the travel tracks, simple intuitive backward and forward movement of the lever will control the boat's forward and backward movement. When in the start track, however, the engine can be started and, according to the invention, even revved, but the engine is disconnected by the clutch from the propeller so that no boat movement will result.
The guide in accordance with the invention is h-shaped. More particularly the forward tracks are parallel to each other and the backward travel track is in line with the forward travel track. This produces a very easy to learn and use control pattern.
The engine controller also increases engine speed when the lever is moved from the travel end forward in the forward travel track and backward in the backward travel track. Normally, however, the engine speed is only increased after the lever is moved in the travel tracks a predetermined distance from the travel end. Thus the boat will start gently, whether going forward or backward.
According to the invention a spring urges the lever along the crosswise track into the start end. Thus if the lever is released when in a center position, it will automatically slip into the start null position in which the clutch is opened.
The guide in accordance with the invention is a plate formed with slots defining the tracks and along which the lever is movable. The lever has a shaft pivoted in the housing and extending parallel to the crosswise track. The lever is pivotal on the shaft about an axis lying in a plane parallel to the forward and backward tracks.
The engine controller includes a switch operated by the lever when in the start track for allowing the engine to be started. The pitch controller includes a switch operated by the lever when in the start track for opening the clutch. In addition this pitch controller includes a switch operated by the lever when in the travel tracks for closing the clutch.
In order to allow the user to release the lever when under way, a ratchet is provided for releasably retaining the lever in any of a plurality of offset positions in the travel tracks. This ratchet includes a wheel connected to the lever and having a toothed periphery and a spring-loaded element mounted in the housing and engaging the periphery.
REFERENCES:
patent: 3709187 (1973-01-01), Marco et al.
patent: 3724970 (1973-04-01), Kobelt
patent: 3826590 (1974-07-01), Kobelt
patent: 3808237 (1989-09-01), None
patent: 0485745 (1992-05-01), None
Periodical: “Yacht” Aug. 1983, pp. 114 & 115.
Avila Stephen
Dubno Herbert
Nasyc Holding S.A.
Wilford Andrew
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