HELICE

PROPELLER

Abrégé français

La présente invention a pour objet une hélice comportant une pluralité de pales, une source motrice assurant l'entraînement de l'hélice, et une pluralité d'organes de transmission déformables interposés entre l'hélice et la source motrice, qui sont retenus dans les fentes de retenue de l'hélice et de la source motrice. Les organes de transmission sont de forme tubulaire et capables de se déformer pour absorber la force exercée sur les organes de transmission en cas d'impact dans une direction perpendiculaire à l'axe longitudinal de la transmission afin de préserver l'intégrité structurale de l'hélice au cas où l'hélice en mouvement viendrait en contact avec un corps étranger.

Abrégé anglais

A propeller is made up of a propelling unit having a plurality of blades, a
driving unit for driving the propelling unit, and a plurality of deformable
transmission units located between the propelling unit and the driving
unit such that the transmission units are retained in the retaining slots of
the propelling unit and the driving unit. The transmission units are
tubular in shape and capable of deforming to absorb an impact force
exerting on the transmission units in a direction perpendicular to the
longitudinal axis of the transmission units, so as to safeguard the
structural integrity of the propeller at such time when the propeller in
motion is impacted on by a foreign object.

Revendications

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A propeller comprising:
a propelling unit composed of an axial portion and a plurality of
helical blades fastened with said axial portion, said axial portion
consisting of an outer hub of a cylindrical construction and an inner hub
located in said outer hub such that a first axial hole of said inner hub is
coaxial with said outer hub, said first axial hole provided in an inner wall
thereof with a plurality of first retaining holes extending along the
direction of a longitudinal axis of said first axial hole, said axial portion
further consisting of a plurality of ribs made integrally therewith;
a driving unit located in said first axial hole and provided in an
outer wall thereof with a plurality of second retaining slots extending
along the direction of a longitudinal axis of said driving unit; and
at least one transmission unit located between said inner hub
and said driving unit such that said transmission unit is implanted in one
of said first retaining slots and one of said second retaining slots;
wherein said transmission unit is tubular in shape and capable of
deformation at such time when said transmission unit is exerted on by a
force in a direction perpendicular to an axis of said transmission unit.
2. The propeller as defined in claim 1, wherein said transmission
unit is a spiral tube having a pitch.
3. The propeller as defined in claim 1, wherein said driving unit is

located in said first axial hole such that there is a ring-shaped interstice
between said driving unit and an inner wall surface of said first axial
hole.
4. The propeller as defined in claim 2, wherein said transmission
unit is provided with at least one bracing unit which is implanted in said
transmission unit.
5. The propeller as defined in claim 4, wherein said bracing unit is
rod-shaped.

Description

CA 02212810 1997-08-12
PROPELLER
FIELD OF THE INVENTION
The present invention relates generally to a boat propelling system,
and more particularly to a propeller intended for use in conjunction with
the boat propelling system.
BACKGROUND OF THE INVENTION
The U.S. Pat. No. 4,566,855 discloses a propeller consisting of a
propelling unit having a plurality of helical blades serving to propel the
craft by the backward thrust of water, a driving unit driven by the engine,
and a rubber sleeve located between the driving unit and the propelling
unit. The connecting portions of the propelling unit, the sleeve, and the
driving unit are provided respectively with a plurality of elongate
projections or retaining slots enabling the output torsion of the engine to
cause the propelling unit to rotate via the driving unit and the sleeve, so
as to generate the backward thrust of water to propel the boat.
The elastic sleeve is capable of absorbing partially the impact

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force generated instantly by the helical blades upon being impacted on
by a foreign object present in water, thereby mitigating the destructive
effect of the impact force on the blades and the engine drive shaft.
Such a prior art propeller as described above is defective in design
in that the elastic sleeve is rather expensive, and that the elastic sleeve of
a high quality is hard to come by, and further that the shock-absorbing
effectiveness of the elastic sleeve depends greatly on the rigidity of the
sleeve. For example, if the sleeve is insufficiently rigid, the propelling
unit can not be effectively actuated to rotate. On the contrary, if the
sleeve is excessively rigid, the shock-absorbing capability of the sleeve
is greatly undermined.
Another U.S. Pat. No. 7,826,404 discloses a propeller consisting of
a propelling unit and the driving unit, which are provided respectively
with a plurality of rod-shaped elastic members capable of mitigating an
impact force exerting on the blades and capable of being destroyed to
cause the propelling unit and the driving unit to idle, so as to protect the
propeller blades and the engine driving the propeller blades. However,
the destruction of the elastic members can result in the incapacitating of
the boat. Moreover, the job of replacing the destroyed elastic member
can not be done by an amateur without a professional assistance.
SUMMARY OF THE INVENTION
It is therefore the primary objective of the present invention to
provide an improved propeller having a transmission unit capable of

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absorbing or lessening an impact force exerting by a foreign object on
the propeller in motion, so as to protect the structural integrity of the
propeller blades without causing the engine power interruption.
It is another objective of the present invention to provide a
propeller with a transmission unit capable of absorbing an impact force
exerting by a foreign object on the propeller in a form-changing manner.
In keeping with the principle of the present invention, the
foregoing objectives of the present invention are attained by a propeller
consisting of a propelling unit, a driving unit, and transmission units.
The propelling unit and the driving unit are provided in the inner and the
outer edges of the adjoining areas thereof with a plurality of retaining
slots for ret~ining the transmission units capable of transmitting the
output torsion of engine from the driving unit to the propelling unit. The
transmission units are tubular in shape and are capable of deforming to
absorb an impact force.
The foregoing objective, features, functions and advantages of the
present invention will be more readily understood upon a thoughtful
deliberation of the following detailed description of the embodiments of
the present invention with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a perspective view of a first preferred embodiment of
the present invention.

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FIG. 2 shows an exploded view of the first preferred embodiment
of the present invention.
FIG. 3 shows a sectional view of the first preferred embodiment of
the present invention.
FIG. 4 shows a sectional view of a portion taken in the direction
indicated by a line 4-4 as shown in FIG. 3.
FIG. 5 shows a sectional schematic view of the present invention
at work.
FIG. 6 shows a sectional view of a second preferred embodiment
of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIGS. 1-5, a propeller 10 embodied in the present
invention is composed of a propelling unit 12, a driving unit 14, and a
plurality of transmission units 16 located betwéen the propelling unit 12
and the driving unit 14.
The propelling unit 12 has an axial portion 20 and three helical
blades 26 made integrally with the axial portion 20 such that the blades
26 are separated from one another in an equiangular manner. The axial
portion 20 has an outer hub 21 of a cylindrical construction for mounting

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thereon the blades 26, and an inner hub 22 of a cylindrical construction
and located in the outer hub 21. The inner hub 22 has a first axial hole 23
coaxial with the outer hub 21. The first axial hole 23 is provided in the
inner wall thereof with eight first retaining slots 24 extending along the
direction of the longitudinal axis of the first axial hole 23 such that they
are equiangularly separated from one another. Located between the outer
wall of the inner hub 22 and the inner wall of the outer hub 21 are three
ribs 25 which are equiangularly separated from one another.
The driving unit 14 is tubular in shape and located in the inner hub
22. The driving unit 14 has a second axial hole 40 which is provided in
the inner wall thereof with a plurality of racks 42 extending in the
direction of the longitudinal axis of the second axial hole 40. The second
axial hole 40 is further provided in the outer wall thereof with eight
second retaining slots 44 extending in the direction of the longitudinal
axis of the second axial hole 40 such that the second retaining slots 44
are opposite in location to one another. The second retaining slots 44 are
similar in a cross-sectional shape to the first retaining slots 24. The
cross-sectional shape may be semicircular, arcuate, or rectangular.
The transmission units 16 are tubular in shape and are made
integrally of an expandable metal material having an appropriate rigidity.
The transmission units 16 are circular in their cross section. The
transmission units 16 may be made of an elongated metal material
having a round or rectangular cross section by a helical extension along
the direction of the longitudinal axis of the material at a relatively small
pitch.
The driving unit 14 is first joined with a drive shaft 17 of an

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engine (not shown in the drawing) and is then fitted into the inner hub 22
of the propelling unit,l4. Thereafter, four transmission units 16 are
located between the first retaining slots 24 and the second retaining slots
44. The inner hub 22 and the transmission units 16 are pressed against
by a stop piece 18 and fastened by a nut 15 engaging the drive shaft 17.
The driving unit 14 is driven by the drive shaft 17 to rotate at a high
speed, so as to force the propelling unit 12 to rotate to generate the
backward thrust of water to propel the boat.
As shown in FIG. 5, each of the transmission units 16 is exerted on
by a shearing force at the moment when the blades 26 of the propeller 10
are impacted on by a hard object present in the water in which the
propeller 10 works. The shearing force may be so destructive that the
transmission units 16 are caused to collapse. Such a structural
breakdown of the transmission units 16 serves to safeguard the structural
integrity of the blades 26 and the driving shaft 17. The transmission
units 16 are capable of such a protective deed as described above in view
of the fact that the transmission units 16 are of a tubular construction
capable of absorbing an impact force at the time of destruction of the
tubular construction by the impact force.
In fact, the transmission units 16 have operational advantages in
that they are expandable, and that they are deformed by the impact force
exerting thereon without being severed outright, and f'urther that the
original opposite arrangement of the first retaining slots 24 and the
second retaining slots 44 is changed slightly to an alternate arrangement
in the course of impact, thereby causing the deformed transmission units
16 to remain in the retaining slots 24 and 44 so as to enable the
propelling unit 12 and the driving unit 14 to operate normally.

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If the transmission units 16 are of a helical tubular construction,
their diameter is first shortened when they are deformed by a force
exerting thereon in a direction perpendicular to their axis. However, such
helical and tubular transmission units 16 are capable of recovering their
original form upon being relieved of a force exerting thereon, provided
that the force in question is not so excessive as to cause a permanent
deformation of the transmission units 16. As a result, the propeller 10 of
the present invention is relatively less vulnerable to destruction.
Moreover, the helical transmission units 16 of the present invention may
be provided respectively with a rod-shaped bracing unit 19, which is
inserted thereinto so as to facilitate the implanting of the transmission
units 16 in the first retaining slots 24 and the second retaining slots 44.
As shown in FIG. 6, the driving unit 14 has an outer diameter
smaller than the inner diameter of the first axial hole 23. For this reason,
a ring-shaped interstice 46 is formed between the outer wall surface of
the driving unit 14 and the inner wall surface of the first axial hole 23
when the driving unit 14 is located in the center of the inner hub 22. The
ring-shaped interstice 46 serves to provide the transmission units 16 an
extra space which may be needed to accommodate the deformation of
the transmission units 16 for enhancing the impact-absorbing effect of
the transmission units 16.

Dessin représentatif