Background Art In general, a vessel, a water-surface aircraft or the like is utilized as transportation means on the waters.

The vessel moves by means of the propulsive fore of a screw, which is rotated by a driving power transmitted from the engine via a power transmission mechanism.

On the other hand, the water-surface aircraft can be moved by a propeller rotated by the driving power of the engine. In contrast with a wheel, the water-surface aircraft is provided with a floating member'mounted thereon, by which it is movable in a floated state on the water surface, FIG. 1 shows a conventional screw device, in which the screw device is denoted by a reference numeral 2. The screw device 2 of FIG. 1 is provided with a screw shaft 4 and a screw mounted at one end of the screw shaft 4. The screw 6 is composed of a plurality of vanes and rotated by the power

transmitted from the engine. The rotating screw 6 moves the vessel body by pushing out the water.

In the above conventional screw device 2, when the screw 6 is operated, a propulsive force 10 is'generated in the moving direction, while forming a wide eddy current 8 in the surrounding of the screw 6, as denoted by an arrow.

Therefore, the screw device 2 of FIG. 1 embraces a problem in that the generated propulsive force is significantly lost to the surroundings due to the formation of wide eddy current 8, leading to waste of fuel.

Disclosure of Invention Therefore, the present invention has been made in order to solve the above problems occurring in the prior art, and it is an object of the present invention to provide a hollow type impeller for a water surface shifter, in which a driving force is transferred from an engine of the water surface shifter via a roller-tooth wheel to a crown sprocket gear integrally formed with a hollow tube, so that the hollow tube and an impeller provided therein are rotated, thereby generating a high-speed propulsive force to move the water surface shifter.

In order to accomplish the above object, according to one aspect of the invention, there is provided a hollow type impeller for a water surface shifter such as a vessel or a water-surface aircraft. The hollow type impeller includes: a hollow tube-impeller assembly having a hollow tube and an impeller formed on the inner peripheral surface of the hollow tube, for discharging air or water at a high speed when rotated; a roller-tooth wheel for transferring a driving power from an engine of the water surface shifter via a power transmission shaft to the hollow tube-impeller assembly; a crown sprocket, gear integrally formed on the outer

peripheral surface of the hollow tube and engaged with the roller-tooth wheel; and a hollow tube-type impeller housing formed at the outside of the hollow tube-impeller assembly, such that the impeller can carry out suction and discharge of water and air while rotating at a high speed by means of the driving power transmitted by the roller-tooth wheel, whereby a propulsive force is generated to move the water surface shifter in a floated state above the water surface.

The hollow type'impeller of the invention may further include: a plurality of magnetic members formed at certain intervals along the outer peripheral surface of the hollow tube which includes the impeller formed on the inner peripheral surface thereof ; a plurality of coil windings formed protrudingly at certain intervals outside of the magnetic members, each coil winding being wound with a coil therearound ; and a control unit for applying an electric power to the coil of the coil winding according to data set therein, to thereby rotate the hollow tube.

Brief Description of Drawings Further objects and advantages of the invention can be more fully understood from the following detailed description taken in conjunction with the accompanying drawings in which: FIG. 1 shows a conventional screw device ; FIG. 2 illustrates a cross-sectional view of a hollow tube- type impeller device for a water surface shifter according to one embodiment of the invention ; FIG. 3 is a cross-sectional view taken along the line A-A in FIG. 1; FIG. 4 shows a cross-section view of the hollow type- impeller assembly in the hollow tube-type impeller device of

FIGS. 2 and 3 ; FIG. 5 shows one embodiment of the impeller according to the invention ; FIG. 6 shows another embodiment of the impeller according to the invention ; FIG. 7 shows one example, in which the hollow tube type impeller device for a water surface shifter according to the invention is applied to an aircraft; FIG. 8 depicts another example, in which the hollow tube type impeller device according to the invention is applied to an aircraft; FIG. 9 shows another example, in which the hollow tube type impeller device according to the invention is applied to a vessel; FIG. 10 is a cross-sectional view taken along the line B-B in FIG. 9 and FIG. 11 illustrates a cross-sectional view of the hollow tube type impeller device for a water surface shifter according to another embodiment of the invention.

Best Mode for Carrying Out the Invention Referring to the accompanying drawings, the preferred embodiments according to the present invention are hereafter described in detail.

FIG. 2 illustrates a cross-sectional view of a hollow tube- type impeller device for a water surface shifter according to íl one embodiment of the invention. FIG. 3 is a cross-sectional view taken along the line A-A in FIG. li FIG. 4 shows a cross-sectional view of the hollow type- impeller assembly in the hollow tube-type impeller device of FIGS. 2 and 3.

Conventionally, the vessels and water-surface aircrafts are

propelled by a water surface shifter mounted thereon. The water surface shifter uses a screw device as the propulsion means, which is operated by the driving power of an engine equipped in the vessel or water-surface aircraft. iAs an improvement in the propulsion means, the hollow tube-type impeller device 20 for the water surface shifter of the invention is provided with a roller-tooth wheel 26 engaged with a crown sprocket gear 28, as shown in FIGS. 2 to 4. The roller-tooth wheel 26 is operated by a power transmission shaft 24, which transfers the driving power of an engine 22 to the crown sprocket gear 28 via the roller- tooth wheel 26.

The crown sprocket gear 28 is integrally formed with the outer peripheral surface of a hollow tube 30, which has a predetermined length. The hollow tube 30 is provided with an impeller 31 formed on the inner peripheral surface thereof. When the hollow tube 30 is rotated together with the impeller 31, air or water on the water surface is discharged at a high speed. The hollow tube 30 and the impeller 31 constitute a hollow tube- impeller assembly 32.

In addition, an impeller housing 34 is assembled at the outside of the hollow tube-impeller assembly 32 such that it can be rotated at a high speed by the driving power transmitted through the roller-tooth wheel 26.

The hollow tube-impeller assembly 32 has a predetermined diameter and length. On the outer peripheral surface of the hollow tube-impeller assembly is formed the crown sprocket gear 28, which is tooth-engaged with the roller-tooth wheel 26 of the power transmission shaft 24 : A flange-type support vane 36 is formed slantly at opposed sides of the crown sprocket gear 28 on the outer peripheral surface of the hollow tube-impeller assembly.

Furthermore, the hollow tube 30 of the hollow tube-impeller

assembly 32 is provided with the impeller on the inner peripheral surface thereof, such that, the intake and discharge of air or water can be carried out inside the hollow tube 30 having a certain length. The impeller 31 may be formed in various shapes and patterns, depending on the design of the hollow tube type impeller device of the invention.

FIGS. 5 and 6 show another embodiments of the impeller, which can be applied to the hollow tube type impeller device of the invention. As shown in FIGS. 5 and 6, the number and shape of the vanes of the impeller 31 may be varied with the design of the whole hollow tube type impeller device.

In addition, the hollow tube-type impeller housing 34 is provided with a wheel cover 38 for the roller-tooth wheel, such that the power transmission shaft 24, to which the roller-tooth wheel 26 is fixed, is installed thereon. At the both sides of the wheel cover 38 is formed a slanted pressure piece 40, which is biased by a resilient member 48 and pressurizes each support vane of the hollow tube 30. Also, a support and guide portion 44 is formed and a sliding pad 42 for facilitating the sliding motion is inserted therein.

The hollow tube type impeller housing 34 enables the crown sprocket gear 28 and the roller-tooth wheel 26 to be firmly engaged with each other and to be rotated at a high speed.

Furthermore, it avoids introduction of foreign materials or water into the engaging portion of the crown sprocket gear 28 and the roller-tooth wheel 26, thereby preventing the increase in the friction force thereof.

FIG. 7 shows one example, in which the hollow tube type impeller device for a water surface shifter according to the invention is applied to an aircraft. In the example of FIG. 7, the hollow tube type impeller device 20 is mounted on both sides in the rear portion of the body of the aircraft 46 to thereby

provide a supplemental propulsive force.

FIG. 8 depicts another example, in which the hollow tube type impeller device for a water surface shifter according to the invention is applied to an aircraft. As shown in FIG. 8, in this example, a hollow tube type impeller device 20a of the invention is mounted in the rear side of the body of the aircraft 47 in order to generate a propulsive force.

Simultaneously, another, hollow tube type impeller device 20b is installed at the front side of the aircraft 7 in order for the front portion thereof to be floated above the water surface with a certain height.

According to the invention, therefore, the hollow tube type impeller device may be mounted in any appropriate position, depending on the design of an aircraft, not limited to a certain specific position.

FIG. 9 shows another example, in which the hollow tube type impeller device according to the invention is applied to a vessel. FIG. 10 is a cross sectional view taken along the line B-B in FIG. 9. In this example, an hollow tube type impeller device 20c is provided at the bottom of the vessel 48 having an air tank and the like, such that it carries out suction and discharge of water, thereby forwarding the vessel in a floated state above the water surface with a certain height.

The operation of the invention describe above will be explained below. First, the hollow tube type impeller device 20 of the invention is operated by the driving power transferred thereto via the power transmission shaft 24. The driving power is generated from an engine equipped llin the vessel 48 or the water-surface aircraft 46.

In other words, the roller-tooth wheel 26 of the power transmission shaft 24 rotates the crown sprocket gear 28, which is integrally formed with the outer peripheral surface of the

hollow tube 30 in the hollow tube-impeller assembly 32. Owing to the integral structure of the hollow tube 30 and the crown sprocket gear 28, the hollow tube 30 is rotated at a high speed, and thus the impeller 31 provided therein carries out high-speed suction and discharge of air or water, while it rotates.

In the hollow tube-type impeller housing 34, the support vane 36 is integrally formed with the'outer peripheral surface of the hollow tube 30, and resiliently supported by the pressure piece 40 made of carbon materials, which is biased by the resilient member 48. Also, a plurality of sliding pads 42 is inserted in both sides of the support vane 36. Therefore, this structure of the invention facilitates the high-speed rotation of the hollow tube-impeller assembly 32.

Therefore, the vessels or aircraft equipped with the hollow tube type impeller device of the invention can move on the water surface in a floated state thereabove, so that they can be used as leisure sports or water-surface transportation means.

FIG. 11 illustrates a cross-sectional view of the hollow tube type impeller device for a water surface shifter according to another embodiment of the invention, in which the impeller device is denoted at 200. The hollow tube type impeller device 200 of this embodiment comprises a plurality of magnetic members 50 mounted, at certain intervals, along the outer peripheral surface of a hollow tube 300, and a plurality of coil windings 54 formed protrudingly at certain intervals outside the magnetic members 50. The coil winding 54 is wound with a coil 52 and spaced apart from the magnetic member 50. Similar to the previous embodiment, an impeller 310 is provided on the inner peripheral surface of the hollow tube 300. The hollow tube type impeller device 200 is also provided with a control unit 56, which applies an electric power to the coil 52 of the coil winding 54 according to the data set therein, thereby rotating

the hollow tube 300.

In the hollow tube type impeller device 200 having the above-described construction, the control unit 56 applies the electric power in sequence to the coil'52 of the coil winding 54, such that the hollow tube 300 with the magnetic members 50 mounted thereon can be rotated, along with the impeller 310 provided therein. Therefore,'the rotating impeller 310 generates a propulsive force by carrying out suction and discharge of water or air.

Industrial Applicability As described above, the hollow type impeller of the invention can be mounted on a vessel or aircraft capable of moving in the sea, the lake, the river or the like and generate a propulsive force while floating them, thereby enabling a high- speed gliding or cruise on the water surface.

Furthermore, when it is mounted to the vessel or water- surface aircraft, the hollow type impeller of the invention can generate a concentrated propulsive force to thereby enable a high-speed gliding or cruise thereof, as compared with the conventional screw device causing a dissipation of propulsive force. Therefore, the technology of this invention will make a great contribution to the propulsion generator in the industry of vessel and aircraft manufacturing.

While the present invention has been described with reference to the particular illustrative embodiments, it is not to be restricted by the embodiments but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention.