Propeller for watercraft

Abstract

A propeller includes a blade device and a driving device. The blade device includes a ring-shaped base with an inner base surface and defining a base axis, and a plurality of curved blades, each of which extends from the inner base surface of the ring-shaped base toward the base axis. The blades are angularly spaced apart from each other relative to the base axis, and cooperate to define a flow space located in the ring-shaped base at the base axis. The driving device drives the blade device to rotate about the base axis.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a propeller, more particularly to a watercraft propeller.

2. Description of the Related Art

Referring to FIGS. 1 and 2, conventional propellers 1 are mounted on two sides of a watercraft 9 to enable forward advancing movement of the latter on a body of water. Each propeller 1 includes a hub 11, a plurality of blades 12 extending from the hub 11 and angularly spaced apart from each other, and a motor 13 having a propeller shaft connected to the hub 11. When the hub 11 is driven by the motor 13 to rotate, the blades 12 rotate accordingly to enable water flow in a front-to-rear direction.

In the aforesaid propeller 1, the hub 11 occupies a central region surrounded by the blades 12. Hence, water is unable to flow through the central region and only flows through clearances among the blades 12. There is thus a need to increase the volume of water that can be moved by the propeller 1 to promote propelling efficiency of the same.

SUMMARY OF THE INVENTION

Therefore, the object of the present invention is to provide a propeller that can overcome the above drawback associated with the prior art.

Accordingly, a propeller of the present invention comprises a blade device and a driving device. The blade device includes a ring-shaped base with an inner base surface and defining a base axis, and a plurality of curved blades, each of which extends from the inner base surface of the ring-shaped base toward the base axis. The blades are angularly spaced apart from each other relative to the base axis, and cooperate to define a flow space located in the ring-shaped base at the base axis. The driving device drives the blade device to rotate about the base axis.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment with reference to the accompanying drawings, of which:

FIG. 1 is a schematic view of a watercraft mounted with a pair of conventional propellers;

FIG. 2 is a schematic view of the conventional propeller;

FIG. 3 is an exploded perspective view of the preferred embodiment of a propeller according to the present invention;

FIG. 4 is an exploded schematic sectional view of the preferred embodiment;

FIG. 5 is a fragmentary schematic view of the preferred embodiment for illustrating engagement between a blade device and a driving device;

FIG. 6 is a fragmentary schematic view of the blade device of the preferred embodiment for illustrating connection of blades to an inner base surface of a ring-shape base of the blade device;

FIG. 7 is a partly sectional, schematic side view of the preferred embodiment; and

FIGS. 8 and 9 are schematic views to illustrate the preferred embodiment when mounted on a watercraft.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 3 to 7, the preferred embodiment of a propeller according to the present invention is shown to comprise a retaining unit 2, a blade device 3, and a driving device 4.

The retaining unit 2 includes an annular seat 21 that is formed with an annular base retaining space 22. The seat 21 includes first and second seat parts 211 that are connected to each other and that cooperate to define the base retaining space 22.

The blade device 3 includes a ring-shaped base 31 retained rotatably in the base retaining space 22 and defining a base axis (L), and a plurality of curved blades 32. The ring-shaped base 31 has an inner base surface 311 surrounding the base axis (L), and an outer base surface opposite to the inner base surface in radial directions relative to the base axis (L) and formed with gear teeth 312. The ring-shaped base 31 further has first and second ends opposite to each other along the base axis (L). Each of the first and second ends of the ring-shaped base 31 is formed with an annular groove 313. The blades 32 extend from the inner base surface 311 of the ring-shaped base 31 toward the base axis (L), are angularly spaced apart from each other relative to the base axis (L), and cooperate to define a flow space 33 located in the ring-shaped base 31 at the base axis (L). Each of the blades 32 is in the shape of a bent curved fan, and has a curved edge portion 321 inclined relative to the base axis (L) and connected to the inner base surface 311 of the ring-shaped base 31 (see FIG. 6), and a corner portion 322 with a tip that extends into the flow space 33.

The retaining unit 2 further includes bearing components 23 disposed in the base retaining space 22 between the seat parts 211 of the seat 21 and the opposite ends of the ring-shaped base 31. While the bearing components 23 in this embodiment include a plurality of ball bearings 231 received in the annular grooves 313, the actual configuration of the bearing components should not be limited thereto in practice.

The seat 21 is formed with a cutout 210 (see FIG. 5) to expose some of the gear teeth 312 of the ring-shaped base 31. The driving device 4 includes a drive gear 41 that meshes with the exposed gear teeth 312 of the ring-shaped base 31, and a drive member 42, such as a drive motor, for driving rotation of the drive gear 41. The driving device 4 drives the blade device 3 to rotate about the base axis (L).

During operation, the drive member 42 rotates the drive gear 41 so as to rotate the ring-shaped base 31 together with the blades 32 about the base axis (L). As a result, water can be moved to flow through clearances among the blades 32 in a front-to-rear direction, as well as through the flow space 33 defined by the blades 32 and located in the ring-shaped base 31 at the base axis (L). Hence, the volume of water that can be moved without obstruction by the propeller of this invention is increased to promote propelling efficiency.

Referring to FIGS. 8 and 9, the propeller of this invention is applied to a watercraft 5. The watercraft 5 has a bottom part formed with a flow duct 51 that extends in a front-to-rear direction. The propeller is mounted on the bottom part of the watercraft 5 such that the blade device 3 is disposed in the flow duct 51. When the driving device 4 drives rotation of the blade device 3, water is able to flow through the flow duct 51 in the front-to-rear direction to enable forward advancing movement of the watercraft 5. In practice, the propeller may be mounted on lateral sides of a watercraft to achieve the same propelling effect.

It should be noted herein that the propeller of this invention may be modified such that a single drive device 4 is employed to drive rotation of more than one blade device 3 so as to further promote the propelling efficiency.

While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.

Claims

1. A propeller comprising:

a blade device including a ring-shaped base with an inner base surface and defining a base axis, and a plurality of curved blades, each of which extends from said inner base surface of said ring-shaped base toward said base axis, said blades being angularly spaced apart from each other relative to said base axis and cooperating to define a flow space located in said ring-shaped base at said base axis; and

a driving device for driving said blade device to rotate about said base axis.

2. The propeller as claimed in claim 1, wherein said ring-shaped base further has an outer base surface formed with gear teeth, said driving device including a drive gear meshing with said gear teeth, and a drive member for driving rotation of said drive gear.

3. The propeller as claimed in claim 1, further comprising a retaining unit that includes an annular seat formed with an annular base retaining space that surrounds said base axis and that has said ring-shaped base retained rotatably therein.

4. The propeller as claimed in claim 3, wherein said retaining unit further includes bearing components disposed in said base retaining space between said annular seat and said ring-shaped base.

5. The propeller as claimed in claim 4, wherein said ring-shaped base further has first and second ends opposite to each other along said base axis, each of said first and second ends of said ring-shaped base being formed with an annular groove, said bearing components including a plurality of ball bearings received in said annular grooves in said first and second ends of said ring-shaped base.

6. The propeller as claimed in claim 1, wherein each of said blades has a curved edge portion inclined relative to said base axis and connected to said inner base surface of said ring-shaped base, and a corner portion with a tip that extends into said flow space.