Marine propulsion – Jet drive
Patent
1995-11-20
1997-07-22
Swinehart, Edwin L.
Marine propulsion
Jet drive
440 47, B63H 1100
Patent
active
056498438
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
a) Field of the Invention
The invention is directed to a water jet propulsion unit for watercraft with a pump and a stator and a nozzle for generating a propulsive water jet and with control elements for changing the direction of the water jet.
b) Description of Related Art
There are many known examples of water jet propulsion units for watercraft in which the water which is sucked in via a pump and accelerated exits as a directed jet via a nozzle which influences its direction, turbulence being eliminated in the water jet via a stator.
For example, U.S. Pat. No. 4,992,065 shows a water jet propulsion unit having a nozzle which is arranged downstream of the stator and supported so as to swivelable about a vertical axis. The outlet opening of the nozzle can be changed via flaps which are swivelable about an axis oriented horizontally thereto until the direction of the water jet is reversed for the purpose of controlled movement in reverse.
A construction of this kind is extremely costly due to the control elements, poses considerable sealing problems for the accelerated water jet, and causes a substantial cross-sectional portion of the water jet to be cut off, in particular when deflecting angles are large. As a result of these deflection losses, the reverse thrust is reduced in such a way that maneuvering problems occur especially through passes having currents and in narrow harbors. Further, a corresponding steering effect must be allowed for; otherwise, a reversing of the directional effect takes place when changing from forward to reverse motion which further complicates the control elements and leads to errors.
Simpler constructions, e.g., in the form of two flaps which are arranged downstream of the outlet opening and are swivelable respectively about vertical axes (see GB 1 190 735), result in a totally unsatisfactory steering effect of the water jet propulsion unit when stopped and at slow speed.
To prevent flow losses it is also known to construct the nozzle serving as a control from concentrically supported spherical surfaces. This is also costly and requires complicated controlling and sealing elements--see DE 26 44 743 A1.
For the above reasons, there is a substantial need for improvement of such water jet propulsion units for the controlled forward and reversing motion of a watercraft of whatever kind.
OBJECT AND SUMMARY OF THE INVENTION
Proceeding from the known shrouded ship propellers, so-called bow thrusters, which enable steering with the stem or stern post of a watercraft--see YACHT 17/1993, pages 28 to 30--the object of the present invention is to provide an improved water jet propulsion unit whose controlling elements are constructed in a simpler manner than is conventional and which enable a watercraft outfitted with a water jet propulsion unit of this kind to be controlled more effectively than was previously possible.
This object is met according to the invention in that the controlling elements comprise at least one nozzle which is supported so as to be displaceable axially between a maximum open position and a minimum open position, a gear unit enabling the rotor of the pump to be driven in both the clockwise and counterclockwise directions, and a pivot bearing which enables the housing supporting the nozzle and pump to execute swiveling movements of at least .+-.90.degree. vertically to the axis of rotation of the pump.
According to a first embodiment form of the invention, nozzles arranged in a mirror-inverted and identical manner are associated with the pump upstream and downstream, respectively, both nozzles being supported so as to be displaceable axially independently from one another in such a way that when one nozzle is positioned, for instance, in the axial open position, the other nozzle is displaceable in the direction of the minimum open position and vice versa.
According to another feature of the invention, the rotor of the pump can be driven in the clockwise direction as well as in the counterclockwise direction via a distributor gear u
REFERENCES:
patent: 3249083 (1966-05-01), Irgens
patent: 3593686 (1971-07-01), Cooper
patent: 3605672 (1971-09-01), Strumbos
patent: 4992065 (1991-02-01), Torneman et al.
Article From Yacht Authored by Von Joachim F. Muhs Entitled "Schub Im Bug," Published on Aug. 11, 1993, pp. 28-31.
Patent Abstracts of Japan, vol. 14, No. 355 Published on Jul. 31, 1990 For JPA 02 124395.
International Publication WO 84/01759 and Corresponding Search Report Published Under the Patent Cooperation Treaty on May 10, 1984.
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