Marine propulsion – Screw propeller – With means effecting or facilitating movement of propulsion...
Patent
1995-02-01
1996-06-04
Sotelo, Jesus D.
Marine propulsion
Screw propeller
With means effecting or facilitating movement of propulsion...
114150, B63B 512
Patent
active
055227457
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a boat propulsion unit intended to be suspended on the outside of a boat transom, said unit comprising a propeller drive shaft housing, a suspension arrangement intended to be fixedly secured to the transom, pivot means which pivotally connect the drive shaft housing to the suspension arrangement to allow pivotal displacement of the drive shaft housing relative to the suspension arrangement about a pivot axis in a vertical plane and a pivot axis in horizontal plane, steering means which is arranged to effect pivotal displacement of the drive shaft housing about said first-mentioned axis, and trim and tilt means which is arranged to effect pivotal displacement of the drive shaft housing about said second-mentioned axis.
Conventional boat propulsion units of the so-called Aquamatic.RTM. type incorporate a carrier screwed to the boat transom. The propeller drive shaft housing is suspended from the carrier by means of a forked bracket which is pivotable about a horizontal transverse axis accommodated in the carrier. A substantially vertical steering axis or spindle is connected to the drive shaft housing and is journalled in the forked bracket. A steering arm cooperates with said spindle. The steering mechanism of the boat, for example a push-pull cable or a servo unit, acts on the steering arm in order to cause its displacement and thereby that of the propeller drive shaft housing. Trimming and tilting of the drive shaft housing is achieved by pivoting the forked bracket upwardly. This is normally carried out with the help of a pair of hydraulic cylinder arrangements, with one hydraulic cylinder acting on each leg of the forked bracket.
It is a general object of the present invention to provide a boat propulsion unit which can be produced at a considerably lower cost than propulsion units of the above-described known type and which, in addition, is simpler to install on a boat.
More particularly, it is an object to provide a propulsion unit with which certain trimming of the unit depending on the speed of the boat can automatically be achieved in a simple manner.
This is achieved in accordance with the present invention by means of the trim means comprising at least one piston-cylinder arrangement having a cylinder space in communication with a water inlet such that the ram pressure created by the water flowing into the water inlet and dependent on the speed of the boat during forward motion generates a pressure in the cylinder space which strives to trim the propulsion unit away from the transom.
Advantages attained by the invention will be apparent from the following description and with reference to the embodiment shown in the attached drawings, of which FIG. 1 shows a schematic partial sectional view of a boat propulsion unit according to the invention and FIG. 2 is an enlargement of the region II of FIG. 1.
In FIG. 1, reference numeral 1 generally denotes a boat propulsion unit of the so-called INU-type, for example an Aquamatic.RTM.-drive unit, which consists of two main components, namely a suspension arrangement 2 and a propeller drive shaft housing 3.
The suspension arrangement 2 consists of two main parts, i.e. a frame member 5 affixed to a boat transom 4 and an inner carrier 6 supported by the frame member 5. The frame member 5 is an extruded aluminium profile, which presents a hollow cavity 7 that can be used for various purposes. For example, the cavity can be used to conduct exhaust gases and cooling water from an engine 8 connected to the propulsion unit 1, whereby the cavity presents an inlet (not shown) and an outlet 9 for the cooling water and the exhaust gases. Alternatively, the frame member 5 can be used as a cooler for various fluids, for example engine oil, whereby the lubrication system of the engine communicates via not shown inlets and outlets with the cavity 7 in the frame member 5.
The aluminium profile which forms the frame member 5 is provided with a U-shaped slot 10 in which a seal 11 is inserted. The frame member 5 is affixed to the outside of t
REFERENCES:
patent: 4140075 (1979-02-01), Berkham
patent: 4362514 (1982-12-01), Blanchard
patent: 5217399 (1993-06-01), Strang
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