Marine propulsion – Jet drive – Having means to prevent clogging
Reexamination Certificate
2000-01-28
2001-09-04
Morano, S. Joseph (Department: 3617)
Marine propulsion
Jet drive
Having means to prevent clogging
C440S038000
Reexamination Certificate
active
06283805
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an improvement in a water jet propelling type outboard motor.
BACKGROUND ART
In Japanese Patent Application Laid-Open No. 9-309492, one example of a water jet propelling type outboard motor is disclosed which pressurizes water which has been drawn from the water by an impeller to jet the same on water surface, thereby obtaining the propelling force.
In a conventional water jet propelling type outboard motor, however, since the entire length of an outboard motor is longer, the center of gravity of a ship is shifted toward the stern of the ship so that the ship is easily put in a state where its bow has been raised. Therefore, the drawback is that straight advancing performance is lowered and meandering occurs easily so that a travelling stability may deteriorate during high speed travelling.
In the outboard motor which has been disclosed in Japanese Patent Application Laid-Open No. 9-309492, water flow rising at the stern of a ship flows in a space formed between a transom board and the outboard motor so that travelling resistance occurs. Also, water flow strikes a lower portion side face of the outboard motor to generate resistance. These resistances negatively impact steering performance.
Japanese Utility Model Application Laid-Open No. 5-65795, discloses an example of a water jet propelling motor provided with forward and rearward moveable screens before and ahead a water suction inlet. The screens prevent floating material such as dust from flowing in the motor through the water suction inlet. By opening the screens, the floating material is captured when the screens are removed due to water flow.
However, a drawback is that when it takes a long time to close the screens, floating material may flow in through the water suction inlet. Also, the inside of the opened rearward screen is subjected to water flow during travelling, and is subjected to contact with floating material. When the rearward screen is closed the floating material attached to the inside of the screen flows in through the water suction inlet. Also, when forward screen moving is closed the floating material becomes trapped between the forward screen and the rearward screen. Accordingly, it is necessary to remove the trapped floating material which is stuck to the screens when the ship stops.
DISCLOSURE OF THE INVENTION
The present invention has been attained in view of the drawbacks in the above-mentioned conventional arts, and an object thereof is to provide a compact water jet propelling type outboard motor having excellent straight advancing performance. Also, another object of the present invention is to provide a water jet propelling type outboard motor where floating material which has attached to the screens can be removed even while a ship is travelling.
In order to attain the objects, a water jet propelling type outboard motor according to a first aspect of the present invention comprises: a casing housing having a front end lower opening, a rear end transverse opening, a first inside space extending from the lower opening obliquely and rearward, and a second inside space extending generally horizontally up to the transverse opening from a rear end of the first inside space; a frame extending upwardly to be mounted to a ship body, a motor mounted on the frame; a gear case disposed transversely ahead of the second inside space and generally vertically above the lower opening; a driving vertical shaft extending downwardly from a motor to be inserted in the gearbox; a following transverse shaft extending transversely and forwardly from the second inside space to be inserted in the gear case; a power transmission mechanism disposed in the gearbox and coupling the driving vertical shaft and the following transverse shaft; and an impeller rotated by the following transverse shaft drawing and pressurizing water from the lower opening to jet the same from the transverse opening.
In the above configuration, the driving vertical shaft extending from the motor and the following transverse shaft for rotating the impeller are coupled to each other by the power transmission mechanism in the gear case, and the gear case is disposed transversely forward of the second inside space and generally vertically above the lower opening. Accordingly, the following transverse shaft can be shortened, and a projecting amount of the outboard motor extending from a ship body rearward can be reduced.
Accordingly, it is hard for the ship to be put in a state where its center of gravity has been shifted to its stern and its bow has been raised, which results in improvement in straight advancing performance during travelling and a travelling stability during a high speed sliding.
The power transmission mechanism can be constituted with an upper bearing rotatably supporting the driving vertical shaft fixed to the gear case, an upper bevel gear fixed to a lower end of the driving vertical shaft, transverse bearing rotatably supporting a front end of the transverse fixed to the gear case, and a transverse bevel gear meshing with the upper bevel gear fixed to the transverse following shaft.
According to the above configuration, as the front end of the transverse following shaft is supported by the transverse bearing, supporting strength of the transverse following shaft is increased so that wobbling is hard to occur in the transverse following shaft.
A second aspect of the present invention is an outboard motor according to the first aspect, further comprising a screen rotatably supported to a front edge of the lower opening and which moves between a closed position where the screen covers the lower opening and an open position where the screen has been shifted downwardly from the lower opening, a biasing member for biasing the screen towards the closed position, an operating shaft which is supported to the casing member rotatably in forward and rearward directions, a first engaging portion which moves together with the screen, and a second engaging portion which moves together with the operating shaft, wherein, when the operating shaft moves from a first position positioned forward to a second position positioned rearward, the first engaging portion is brought into engagement with the second engaging portion to move the screen from the closed position to the open position, and when the operation moves beyond the second position, the first engaging portion is released from the second engaging portion so that the screen is returned back to the closed position from the open position by the basing member.
The first and second engaging portions can be disposed such that a moving region of the second engaging portion obtained when the operating shaft moves from the first position to the second position overlaps a moving region of the first engaging portion obtained when the screen moves from the closed position to the open position.
When the ship travels where there is much floating material such as dust, a probability is increased that floating material will stick to the screen. For this reason, the operating shaft is appropriately moved in an inclination manner from the first position in a travelling rearward direction. Thereby, the second engaging portion is engaged with the first engaging portion, and the screen is moved so as to be opened from the closed position against a biasing force of the biasing member so that the lower opening is opened. At this time, the screen is opened from its rear. When the operating shaft moves beyond the second position, the first engaging portion is released from engagement with the second engaging portion and the screen instantaneously moves to the closed position by a biasing force of the biasing member. After the operating shaft is moved in a travelling forward direction to be returned back to the first position, when the operating shaft is again moved rearward, the screen opens the lower opening. Thus, the screen behaves such that, after it opens the lower opening slowly, it rapidly moves to the closed position.
Accordingly, while the screen is slowly
Howard & Howard
Ishiqaki Company Limited
Morano S. Joseph
Vasudeva Ajay
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