Marine propulsion – Screw propeller – With means effecting or facilitating movement of propulsion...
Patent
1990-05-21
1992-06-30
Peters, Jr., Joseph F.
Marine propulsion
Screw propeller
With means effecting or facilitating movement of propulsion...
440 49, B63H 512
Patent
active
051258587
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention concerns retractable propulsors for boats.
BACKGROUND OF THE INVENTION
Retractable propulsors for boats are known, for example, from the French patent No. 2.229.608.
This document describes an auxiliary propulsor in which the propeller is withdrawn into a cavity forseen under the hull. The propeller is fixed to a shaft which penetrates an upper hollow tube when the propeller is raised. The lifting is carried out by means of a hydraulic jack, one end of which is fast with to a fixed frame and the other to a horizontal plate placed under the propeller. For the rotation of the assembly telescopic elements are housed in another tube fixed to the craft on which the same rotate. The pressure oil contained in the transmission system is used for controlling the hydraulic jack and for rotating the driving shaft.
The main disadvantages which are noted in this embodiment are the lack of mechanical sturdiness, as well as the general kinematic complication due to the fact that the whole assembly must rotate, the possibility of using only hydraulic engines and on the whole the considerable size. Another disadvantage is that of finding the optimal application only on flat-bottomed boats.
OBJECTS OF THE INVENTION
The document DE-B-1 039 874 describes a propulsor unit for boats comprising: a main engine; a fixed tubular part; a main transmission which ends with a substantially vertical shaft which operates a bevel gear pair on the substantially horizontal outlet of which a propeller is placed; an auxiliary transmission which carries out the rotation around a vertical axis of the bottom end of the propeller; a movable assembly which moves vertically with respect to the fixed structure of the boat and is integral in this direction with the bevel gear pair and with the propeller. Said movable assembly is made of an inner part which can rotate with respect to a vertical axis which rests vertically on a movable carriage.
The disadvantage that is noted in said propulsor is that the transversal thrust generated by the propeller is supported by some elements of the hydraulic system, which may disturb their operation. A further disadvantage is that at least some of the elements of the hydraulic system come in contact with the external environment, therefore they may be fouled and consequently may function badly. Furthermore, said propulsor unit is remarkably bulky.
The main aim of this invention is to give the upmost stability to the moveable part bearing the propeller so that the horizontal thrust is well supported by the inner kinematic motion, acquiring on the whole a simple and compact construction.
A further aim is that of obtaining a shape of the hull of the boat as hydrodynamic as possible when the propeller is retracted.
SUMMARY OF THE INVENTION
The main aim is reached by a propulsor for boats as claimed in claim 1.
Preferably the tube is provided with a check tongue which, during its rotation, engages the full part of the tube discharging thereupon the horizontal component of the thrust of the propeller. This tube has a double function: it favours the centering of the carriage in the vertical movement and acts as a shelf when the assembly is in the functioning position, directly opposing the carriage (reverse gear) or the check tongue (forward gear).
Preferably the carriage is moved in a vertical direction by at least one fixed screw engaged with a nut screw integral to the carriage.
The carriage can be hydraulically moved by a piston concentric to the carriage. In such a case the main transmission shaft can be used as a piston. It is also possible to provide a toroidal piston which surrounds the transmission shaft, or else to sue the upper part of the carriage as a piston.
Preferably the power which rotates the propeller is transmitted to a lateral pinion which moves a crown integral with the main transmission shaft.
The pinion can have a horizontal axis and can be connected to a driving shaft with a horizontal axis.
The pinion can be hollow and capable of receiving the hori
REFERENCES:
patent: 1124645 (1915-01-01), Overton
patent: 2156938 (1939-05-01), Edwards
patent: 2466635 (1949-04-01), Brown et al.
patent: 2545086 (1951-03-01), Harris
patent: 2885990 (1959-05-01), Hawthorne
patent: 2987027 (1961-06-01), Wanzer
patent: 3030910 (1962-04-01), Alsager
patent: 3076428 (1963-02-01), Shipley
patent: 3483843 (1969-12-01), Hawthorne
patent: 3587512 (1971-06-01), Patterson
patent: 3685481 (1972-08-01), Mansell
patent: 3807347 (1974-04-01), Baldwin
patent: 4175511 (1979-11-01), Krautkremer
patent: 4274827 (1981-06-01), Catsburg
patent: 4573929 (1986-03-01), Savikurki
Bartz Clifford T.
Peters Jr. Joseph F.
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