Marine propulsion – Jet drive – Direction control for fluid jet
Reexamination Certificate
2000-06-09
2001-10-09
Swinehart, Ed (Department: 3617)
Marine propulsion
Jet drive
Direction control for fluid jet
Reexamination Certificate
active
06299494
ABSTRACT:
FIELD OF THE INVENTION
This invention generally relates to water jet apparatus for propelling boats and other watercraft. In particular, the invention relates to nozzles for a water jet propulsion unit.
BACKGROUND OF THE INVENTION
It is known to propel a boat or other watercraft using a water jet apparatus mounted to the hull, with the powerhead being placed inside (inboard) or outside (outboard) the hull. The drive shaft of the water jet apparatus is coupled to the output shaft of the motor. The impeller is mounted on the drive shaft and installed in a housing, the interior surface of which defines a water tunnel. The impeller is designed such that during motor operation, the rotating impeller impels water rearward through the water tunnel. The reaction force propels the boat forward.
The reaction force can be increased by increasing the speed at which the water jet exits the housing. One technique for accomplishing this is to form the exit portion of the housing in the shape of a nozzle having a convergent passageway which further accelerates the water flow therethrough. This type of nozzle is typically referred to as a thrust nozzle.
In order to provide horizontal directional control for the boat, the emerging water jet is diverted from its precisely rearward flow direction. This diversion is typically accomplished by means of a steering nozzle which is pivotably mounted to the housing in flow communication with the exit nozzle outlet. The pivot axis of the steering nozzle is preferably generally orthogonal to the centerline axis of the exit nozzle. The steering nozzle is typically steered remotely by the boat operator via control rods or cables which are coupled to the steering nozzle by control linkages. The steering nozzle may be pivoted horizontally in either direction to the desired extent to achieve the desired steering effect.
For example, U.S. Pat. No. 3,089,454 discloses a water jet propulsion system comprising a jet-producing nozzle which is surrounded by a housing consisting of two companion members, which are bolted together along adjacent flanges. The companion housing members form an open housing constituting a substantial portion of a hollow sphere. A jet-directing member for steering has an inner or forward portion which also forms part of a hollow sphere concentric with the housing and is rotatable within in the housing in the manner of a ball-and-socket arrangement. This inner or forward portion of the jet-directing member is pivotably mounted by means of a pair of diametrally opposite, radially extending pivot shafts rotatably mounted in the housing. The jet-directing member is pivotable to a limited extent on an axis perpendicular to the axis of the discharging end of the nozzle. A steering arm controls the positioning of the jet-directing member during steering.
In addition to steering, it is frequently desirable to control or change the boat's attitude. This can be accomplished, for example, by providing means for enabling the steering nozzle to pivot about a horizontal axis. This vertical pivoting action is similar to the horizontal pivoting action previously described, except that the range of vertical pivoting needed to provide the desired change in attitude (i.e., trim) angle is typically only about 20 degrees.
A water jet propulsion system having a jet nozzle with both horizontal and vertical pivoting action is disclosed in U.S. Pat. No. 3,776,173. In accordance with this system, the water flows through a housing which terminates in a substantially hemispherical flared portion. The spherical portion of the housing encloses a jet nozzle having a constricting passageway that accelerates the water flow. The nozzle comprises a substantially spherically configured bearing surface that is partially enclosed by and concentric with the flared hemispherical housing portion, the latter bearing against the nozzle bearing surface during rotation of the nozzle. The nozzle can rotate about mutually orthogonal pivot axes to achieve steering and attitude control respectively. During these rotations, the nozzle and flared housing portion behave in the manner of a ball and socket, except that the hemispherical flared housing portion only encloses part of and does not capture the nozzle.
There is a need for an articulated nozzle assembly having a convergent nozzle which can be rotated for both steering and attitude control, but which has a simple construction.
SUMMARY OF THE INVENTION
The present invention is directed to a water jet apparatus having an articulating nozzle assembly comprising a convergent nozzle which serves as both a thrust nozzle and a steering nozzle. The assembly comprises an inner housing or duct having a flanged portion with an inlet and a ball-shaped portion with an outlet, and a convergent nozzle having a socket portion which fits around the ball-shaped portion of the inner duct. This ball and socket arrangement allows the convergent nozzle to revolve about the ball-shaped portion of the inner duct.
In accordance with the preferred embodiment of the invention, rotation of the convergent nozzle about a centerline of the inner duct is prevented by an arrangement wherein a limit pin projecting outward from the duct is slidable in a slot formed in the nozzle wall. The slot has a width slightly greater than the outer diameter of the limit pin and a length greater than its width. Alternatively, the slot could be formed in the ball-shaped portion of the inner duct and the limit pin could extend inward from the nozzle. The slot is disposed to allow the convergent nozzle to tilt relative to the inner duct about a horizontal axis perpendicular to a centerline of the inner duct. Abutment of the limit pin with the ends of the slot limits the trim angle of the nozzle to a predetermined range. At any position of the limit pin along the slot, however, the convergent nozzle will be rotatable about the axis of the limit pin. Preferably a pair of brackets are attached to the nozzle for controlling the trim and steering angles of the convergent nozzle relative to the inner duct.
The preferred embodiment of the invention will be disclosed in the context of water jet propulsion system which is driven by an inboard motor. However, the person skilled in the art will readily appreciate that the articulating nozzle assembly disclosed herein has application beyond water jet propulsion systems driven by an inboard motor. For example, the articulating nozzle assembly disclosed herein has application in a water jet propulsion system driven by an outboard motor.
REFERENCES:
patent: 777053 (1904-12-01), Wilson
patent: 1044164 (1912-11-01), Goodrich
patent: 1196176 (1916-08-01), Tobin et al.
patent: 2111553 (1938-03-01), Chew
patent: 3089454 (1963-05-01), Chronic
patent: 3094966 (1963-06-01), Meyer
patent: 3183878 (1965-05-01), Aschauer
patent: 3776173 (1973-12-01), Horwitz
patent: 3788265 (1974-01-01), Moore
patent: 3888202 (1975-06-01), Willyard
patent: 3946556 (1976-03-01), Catterfeld
patent: 4605376 (1986-08-01), Aschauer
patent: 4964821 (1990-10-01), Tafoya
patent: 5049096 (1991-09-01), Henn
patent: 5222863 (1993-06-01), Jones
Bowers William W.
Mahnich James
Outboard Marine Corporation
Swinehart Ed
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