Marine propulsion – Jet drive
Reexamination Certificate
1999-12-07
2001-07-31
Basinger, Sherman (Department: 3617)
Marine propulsion
Jet drive
C440S041000, C440S042000, C440S047000
Reexamination Certificate
active
06267632
ABSTRACT:
FIELD OF THE INVENTION
This invention generally relates to pump jet apparatus which are mounted to the hull of a boat or other water craft. In addition, the invention relates to mechanisms for transmitting motive power from an inboard marine engine to an outboard pump jet.
BACKGROUND OF THE INVENTION
It is known to propel a boat or other water craft using a pump jet apparatus mounted to the hull, with the powerhead being placed inside (inboard) the hull. The drive shaft of the pump jet apparatus is coupled to the output shaft of the inboard motor. The impeller is mounted on the drive shaft and housed in a jet propulsion pipe or water tunnel.
To facilitate use of pump jet-propelled boats in shallow water, it is known to mount the pump jet at an elevation such that the pump jet does not project below the bottom of the boat hull. This can be accomplished, for example, by installing a duct in the stern of the boat, the duct being arranged to connect one or more inlet holes formed in the bottom of the hull with an outlet hole formed in the transom. The pump jet is then installed outside the hull in a position such that the pump jet inlet is in flow communication with the duct outlet at the transom. Such a system is shown in Australian Patent Specification No. 262306, published in 1963. Alternatively, the pump jet can be installed inside the duct built into the hull, as shown in U.S. Pat. No. 5,181,868.
Alternatively, a water tunnel can be formed in the stern of the boat hull, the water tunnel having a height which gradually increases from the hull bottom at a point in front of the transom to a maximum height at the transom. In one type of design, the pump jet is placed so that its inlet is in flow communication with the outlet of the water tunnel. One example of this type of system is shown in Italian Publication No. 724662.
In another type of design, part of the pump jet apparatus is installed inside the hull while the remaining part penetrates the transom and extends to the rear of the hull. An inlet housing of the pump jet has a horizontal opening and an inclined water tunnel for guiding water to the impeller. The horizontal opening of the inlet housing is mounted in a hole in the bottom or near the bottom of the hull. A similar design is disclosed in Swiss Patent No. 481788.
In many pump jet units powered by inboard engines, the drive shafts and pump mountings (which must penetrate the hull) are placed below the waterline. Such a mounting system has the disadvantage that various gaskets and seals are required to ensure the integrity of the installation. Leakage at any of the mounting and shafting locations can be disastrous.
In addition, in the event that the inlet to the pump jet becomes clogged with debris, permanent mounting of the pump jet makes it difficult to clean out the debris from the inlet. In some instances, removal of the ingested or entangled debris requires that the boat user enter the water or even that the boat be lifted out of the water.
Thus, an arrangement for mounting a pump jet in flow communication with a water tunnel wherein the hull penetrations are located above the waterline provides an advantage. Further, it would be advantageous to mount the pump jet in such a way that it can be removed from its position in flow communication with the water tunnel and into a position which allows easy access to any debris clogging the pump jet inlet.
SUMMARY OF THE INVENTION
One aspect of the present invention encompasses a boat or other water craft having a marine propulsion system comprising an inboard engine, an outboard pump jet apparatus and a transom plate on which the pump jet apparatus is pivotably mounted. In accordance with one preferred embodiment of the invention, the boat hull bottom has a water tunnel formed therein, the transom plate has a tube portion in flow communication with the water tunnel, and the pump jet apparatus has an inlet which, in the operating position of the pump jet, is in flow communication with the tube portion of the transom plate.
The present invention is also directed to an arrangement for providing a boat or other water craft with a pump jet apparatus which is selectively movable from an operating position to a service position and vice versa. In the operating position the pump jet inlet is inaccessible to an occupant of the boat, whereas in the service position the pump jet inlet is accessible, enabling a boat occupant to clear debris from the pump jet inlet. In accordance with a preferred embodiment, the pump jet apparatus is pivotably mounted on the transom plate. When the pump jet is pivoted away from the operating position, the pump jet inlet is disengaged from the tube portion of the transom plate, into a position which allows easy access to remove the debris clogging the pump jet inlet.
In accordance with a further preferred embodiment, the drive shaft connecting the inboard engine to the outboard upper gear assembly and the bolts used to mount the transom plate each penetrate the transom at an elevation above the waterline. This has the benefit that failure of any gasket or seal will not cause disastrous leakage so long as the penetrations remain above the waterline.
Another aspect of the invention encompasses a transom plate for mounting on a boat transom. In accordance with a preferred embodiment, the transom plate comprises a plate having upper and lower portions, and a tube portion connected to the lower portion of the plate. The transom plate further comprises first and second journal boxes connected to the upper portion of the plate for housing a compound gear and various bearings which allow the pump jet apparatus to pivot relative to the transom plate.
The invention is further directed to a pump jet arrangement for mounting on a transom of a boat hull, comprising: a rotor shaft; a rotor (impeller) mounted on the shaft; a drive train coupled to the rotor shaft; a mounting plate having holes for mounting on a transom of a boat hull; a first water tunnel portion connected to the mounting plate and having an inlet and an outlet; a drive train casing pivotably coupled to the mounting plate and encasing a vertical portion of the drive train, the drive train casing being pivotable relative to the mounting plate between first and second positions; and a second water tunnel portion connected to the drive train casing and having an inlet and an outlet, the rotor being housed inside this second water tunnel portion. The inlet of the second water tunnel portion and the outlet of the first water tunnel portion are in abutment when the drive train casing is in the first position and are not in abutment when the drive train casing is in the second position. The inlet of the second water tunnel portion and the outlet of the first water tunnel portion present substantially the same cross-sectional shape to water flowing therethrough.
Another aspect of the invention is the provision of a sealed pivot arrangement which allows the drive train casing of the pump jet apparatus to pivot relative to the mounting plate. The horizontal portion of the drive train penetrates the drive train casing from the side, along the axis of pivoting. Thus the drive train casing and the horizontal portion of the drive train will have relative rotation but no relative displacement during pivoting of the drive train casing.
REFERENCES:
patent: 2975750 (1961-03-01), Smith
patent: 3073277 (1963-01-01), Lee
patent: 3343368 (1967-09-01), Castoldi
patent: 3476070 (1969-11-01), Austen
patent: 3572281 (1971-03-01), Becker
patent: 3603278 (1971-09-01), Gehlen
patent: 3847108 (1974-11-01), Shimanckas
patent: 4010707 (1977-03-01), Bendall
patent: 5181868 (1993-01-01), Gabriel
patent: 262306 (1963-05-01), None
patent: 481788 (1970-01-01), None
patent: 560126 (1975-03-01), None
patent: 1321564 (1963-02-01), None
patent: 724662 (1966-11-01), None
patent: 49-73196 (1974-07-01), None
patent: 50-12672 (1975-02-01), None
patent: 83/00125 (1983-01-01), None
Basinger Sherman
Bombardier Motor Corporation of America
Flaherty Dennis M.
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