Marine propulsion – Jet drive
Reexamination Certificate
2001-03-19
2003-03-11
Avila, Stephen (Department: 3617)
Marine propulsion
Jet drive
C440S040000, C440S042000
Reexamination Certificate
active
06530812
ABSTRACT:
PRIORITY INFORMATION
The present application is based upon and claims priority to Japanese Patent Application No. 2000-077081, filed Mar. 17, 2000 and Japanese Patent Application No. 2000-022733, Jan. 31, 2001, the entire contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a jet propulsion unit for a watercraft, and more particularly, to a secondary thrust arrangement for a small watercraft.
2. Description of the Related Art
Personal watercraft have become very popular in recent years. This type of watercraft is quite sporting in nature and carries a rider and possibly one or more passengers. A relatively small hull in the personal watercraft commonly defines a rider's area above an engine compartment. An internal combustion engine frequently powers a jet propulsion unit which propels the watercraft. The engine lies within the engine compartment in front of a tunnel formed on the underside of the watercraft hull. The jet propulsion unit is located within the tunnel and is driven by an output shaft of the engine. In particular, an impeller shaft of the jet propulsion unit extends forward, through a wall of the hull tunnel, and is coupled to the engine output shaft. In this manner, the engine drives the jet propulsion unit.
The jet propulsion unit conventionally includes an impeller housing in which an impeller is contained. The impeller, which is driven by the engine through the impeller shaft, draws water through a water inlet and forces it through a discharge nozzle to propel the watercraft. A steering nozzle usually is mounted on the discharge nozzle for pivotal movement about a vertical axis. Pivotal movement of the steering nozzle about the vertical steering axis alters a discharge direction of the water jet to steer the watercraft.
Many personal watercraft also include a reverse thrust deflector or “bucket” to issue water forwardly and produce a reverse thrust. A pair of support arms typically support the reverse thrust deflector about the end of the jet propulsion unit. These arms usually are pivotally mounted onto the discharge nozzle or onto a ride plate that extends beneath at least a portion of the jet propulsion unit. The pivotal movement of the arms moves the reverse thrust deflector from a raised position, in which the deflector does not affect the water jet issuing from the steering nozzle, and a fully lowered position, in which the deflector cooperates with the steering nozzle and redirects water issuing from the jet propulsion unit forwardly to achieve a reverse thrust. However, this method of producing a reverse thrust is mechanically inefficient and does not allow for precise steering during reverse motion of the watercraft.
SUMMARY OF THE INVENTION
A need therefore exists for a watercraft thrust arrangement that provides for precise steering movements during reversal of the watercraft and enhanced steering control of the watercraft during forward motion.
One aspect of the present invention is a secondary thrust arrangement configured to provide enhanced steering control of a small watercraft. The secondary thrust arrangement may also be configured to inhibit “diving” of a bow portion of a small watercraft during deceleration. Additionally, the secondary thrust arrangement may be configured to provide precise directional control of the watercraft during low speed docking maneuvers.
In one mode, a watercraft comprising a hull is provided. The hull includes a lower hull portion and an upper deck portion. A handlebar assembly is disposed on the upper deck portion. An engine compartment is defined between the lower hull portion and the upper deck portion and an internal combustion engine is disposed within the engine compartment. A jet propulsion unit, which includes a water inlet, a discharge nozzle, and an impeller driven by the internal combustion engine, is provided. A steering nozzle is disposed on a downstream side of the discharge nozzle, and is configured to pivot about a substantially vertical axis. The jet propulsion unit is configured to, in a first mode, discharge pressurized water from the steering nozzle in a substantially rearward direction from the watercraft. The jet propulsion unit is additionally configured to, in a second mode, discharge pressurized water through at least one discharge port disposed on an outer surface of the hull.
In another mode, a watercraft comprises a hull, the hull including a lower hull portion and an upper deck portion is provided. A handlebar assembly is disposed on the upper deck portion. An engine compartment is defined between the lower hull portion and the upper deck portion. An internal combustion engine is disposed within the engine compartment. A jet propulsion unit comprising a water inlet, a discharge nozzle, and an impeller driven by the internal combustion engine is also provided. A steering nozzle is disposed on a downstream side of the discharge nozzle, the steering nozzle is configured to pivot about a substantially vertical axis. The jet propulsion unit is configured to discharge pressurized water from the steering nozzle in a substantially rearward direction from the watercraft. Means for diverting water from the jet propulsion unit through a discharge disposed on the hull is also provided.
In yet another mode, a watercraft comprises a hull which includes a lower hull portion and an upper deck portion. An engine compartment is defined between the lower hull portion and the upper deck portion. An internal combustion engine is disposed within the engine compartment. A jet propulsion unit is powered by the internal combustion engine. The jet propulsion unit includes a nozzle. The hull includes at least one inlet and at least one discharge port. At least one secondary flow passage is provided connecting the at least one inlet and the at least one discharge port. A water diverter assembly is pivotally supported relative to the nozzle and moveable between a first position and a second position. The water diverter assembly is disposed relative to the nozzle so as to direct at least a portion of a water stream issuing from the nozzle toward the at least one inlet.
In a further mode, a watercraft comprises a hull including a lower hull portion and an upper deck portion. An engine compartment is defined between the lower hull portion and upper deck portion. An internal combustion engine is disposed in the engine compartment and a jet propulsion unit is powered by the internal combustion engine. The jet propulsion unit includes a nozzle and the hull includes at least one inlet and at least one discharge port. At least one secondary flow passage connects the at least one inlet and the at least one discharge port. A water diverter assembly is pivotally supported relative to the nozzle and moveable between a first position and a second position. The water diverter assembly is disposed relative to the nozzle so as to direct at least a portion of a water stream issuing from the nozzle toward the at least one inlet.
In still a further mode, a watercraft comprises a hull including a lower hull portion and an upper deck portion. An engine compartment is defined between the lower hull portion and upper deck portion and an internal combustion engine is disposed in the engine compartment. A jet propulsion unit is powered by the internal combustion engine and includes a discharge nozzle, a steering nozzle and at least one discharge port configured to produce a steering thrust.
Further aspects, features, and advantages of the present invention will become apparent from the detailed description of the preferred embodiments which follows.
REFERENCES:
patent: 5096446 (1992-03-01), Tazaki et al.
patent: 6009822 (2000-01-01), Aron
patent: 6146219 (2000-11-01), Blanchard
patent: 6159059 (2000-12-01), Bernier et al.
patent: 6183318 (2001-02-01), Tsumiyama et al.
Aoyama Yusuke
Gahara Yoshihiro
Koyano Satoshi
Tsukahara Koju
Yamada Hisato
Avila Stephen
Knobbe Martens Olson & Bear LLP
Yamaha Hatsudoki Kabushiki Kaisha
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