Marine propulsion – Screw propeller – Propeller guard
Utility Patent
1999-10-14
2001-01-02
Sotelo, Jesus D. (Department: 3617)
Marine propulsion
Screw propeller
Propeller guard
Utility Patent
active
06168483
ABSTRACT:
BACKGROUND OF THE INVENTION
A) Field of the Invention
The present invention relates to a method and apparatus for protecting a boat propeller, and more particularly to such an apparatus and method which in addition perform a deflecting function and provides other advantageous features.
BACKGROUND ART
Powerboats often find themselves in shallow water and possibly encounter obstacles which extend upwardly from the underwater surface. In other instances, when the boat is simply operating in quite shallow water, the propeller is apt to come into contact with a sandy or muddy river or lake bottom. In either case, this can result in damage to the propeller.
It is an object of the present invention to provide a deflector propeller guard and method for a boat propeller assembly, with a balance of desirable features. More specifically, the present invention provides a protective apparatus which also serves a deflecting function to cause objects or underwater surface material (e.g. dirt, sand, etc.) to be deflected away from the propeller in a manner to alleviate to some extent the impact of such objects and/or material, and also move such objects or material out of the path of the propeller.
Also, it is an object of the present invention to structure the guard apparatus so that it is durable, sturdy, and yet can be economically and conveniently manufactured.
Also, the present invention is particularly adapted to be mounted to a propeller section of a motor where the propeller section has a skeg which extends downwardly from a propeller housing.
SUMMARY OF THE INVENTION
The protection and deflection apparatus of the present invention is adapted to be mounted in an operating position adjacent to a propeller section of a boat. The propeller section has a propeller blade portion having an axis of rotation in an outer circumferential path of rotation along which tip portions of the propeller blade portion travel. The apparatus has a longitudinal axis, a transverse axis and a vertical axis.
The apparatus comprises a forward deflecting section having a forward deflecting axis which extends in a downward and rearward slant. This forward deflecting section comprises right and left deflection plates, each of which comprises:
i) a central deflection edge portion, with the two connecting deflection edge portions joining one another at said deflecting axis;
ii) an outer deflection edge portion, with the two outer deflection edge portions each having a forward end and a rear end, and extending laterally outwardly and downwardly from the forward end of the deflection plate;
iii) a rear deflection section connecting portion;
iv) a generally downwardly and outwardly facing deflection surface, with the two deflection surfaces forming an angle of less than 180 degrees, relative to a plane taken perpendicular to said deflecting alignment axis, so as to extend laterally and upwardly away from one another;
There is a rear guard section having a rear central guard section axis which is generally longitudinally aligned and is at an angle of less than 180 degrees relative to the deflection axis. A forward end portion of the rear guard section is connected to the rear end portion of the forward deflecting section, and it also has a rear end. The guard section comprises right and left guard plates, each of which comprises:
i) a central guard plate connecting edge portion with the two central guard plates connecting edge portions meeting each other at the central guard section axis;
ii) a laterally outward section edge portion having a forward end and a rear end;
iii) a forward guard section connecting portion connected to the rear deflection connecting portion of its related right or left deflection plate;
iv) a generally downwardly and outwardly facing lower guard surface, with the two guard surfaces forming an angle of less than 180 degrees, relative to a plane taken perpendicular to the guard section axis.
Also, in the preferred form the apparatus comprises a mounting section by which the apparatus can be mounted in the operating position. More specifically, in the preferred form this mounting section comprises at least one vertically aligned mounting member adapted to be mounted to a skeg of the propeller section. This mounting section may also comprise a backing plate which is adapted to be placed on a side of the skeg opposite to the side on which the mounting member is positioned, with one or more fasteners extending through the mounting member, the backing plate and the skeg.
The forward end portions of the downwardly facing guard surfaces of the two guard plates are aligned and adjacent to the rear end portions of the downwardly facing deflecting surfaces of the deflection plates. More specifically, in the preferred form, the forward lower surface edge portions of the guard plates are aligned with and immediately adjacent to rear surface edge portions of the deflection plates in a manner to form a continuous lower surface area of the deflection section and the guide section.
In the preferred form, the outer edges of the outer deflection edge portions of the deflection plates meet with and are aligned with forward ends of the outer edges of the guard plates.
Desirably, the angle formed by the two deflection guard surfaces is no less than about a right angle, desirably between about 160 degrees to 100 degrees, and more desirably between about 140 degrees to about 110 degrees. A preferred angle would be about two-thirds of a straight angle.
Also in the preferred form, the angle formed by the two guard surfaces would be no less than about two-thirds of a right angle. Desirably, this angle would be between 150 degrees to 175 degrees, and more desirably between 160 degrees and about 170 degrees. A preferred angle is about 165 degrees.
Also in the preferred form, the forward end portions of the downwardly facing guard surfaces slant inwardly and forwardly toward one another and form an angle between about 160 degrees to 60 degrees, more desirably between about 140 degrees to 80 degrees, and more desirably yet between 120 to 90 degrees. A preferred angle would be approximately 105 degrees.
The outer deflection edge portions of the two deflection plates form an angle between about a right angle and about one-sixth of a right angle taken from a view parallel to the longitudinal center line of the apparatus. More desirably, this angle would be between about 60 degrees to 20 degrees. A preferred angle would be about 30 degrees.
If an angle is formed by the lines resulting from a horizontal plane intersecting the two guard plates at about the longitudinal mid length thereof, these two lines extend rearwardly and outwardly from the forward central axis at an angle between about three-quarters of a straight angle and one-half of a right angle. A more preferred range is between about 110 degrees to 65 degrees, and more preferably about a right angle.
The angle formed by the central guard section axis relative to the deflection axis is desirably no less than about two-thirds of a straight angle. In the preferred form it would be no greater than 160 degrees. A preferred range would be between 150 degrees to 130 degrees. An angle of 140 degrees has been found to be satisfactory.
Also in the preferred form, there are openings formed in the deflection section, and desirably these are in the form of elongate slots, and more desirably, horizontal slots.
Also, the apparatus of the present invention can be made where the forward deflection section and the rear guard section are integrally formed from a single piece of sheet metal which is bent along bend lines to form the apparatus. The bend lines are located along the deflecting axis, along the central guard section axis, an elongate connecting line between one of the deflection plates and one of the guard plates. The other deflection plate and the other guard plate are joined together to form the unitary structure comprising the forward deflection section in the rear guard section.
In the method of the present invention, the apparatus is positioned as noted above. The deflec
Hughes Robert B.
Hughes & Schacht, P.S.
Sotelo Jesus D.
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