Background Art The present invention is an improvement of"a manpower propulsion device of buoyancy"disclosed in Korean Utility Model No. 170881. In the present invention, a boat or a ship is divided into a rubber tube and a structure, which is injection-molded or extrusion-molded and in which urethane and styrene foam is inserted. The rubber tube is suitable to general users enjoying simple leisure and is convenient in carrying because it is collapsible if air is removed from the rubber tube and a propulsion device is detachably mounted. The injection-molded or extrusion-molded buoyancy is not carried but suitable to athletes or amusement spots in pleasure resorts because having strong durability. Therefore, compared with prior arts, the present invention can rapidly transmit driving power to the buoyancy and obtain strong propulsive force.

Furthermore, the present invention can be used as a boat, a ship or water skis by combining a bicycle function to the buoyancy.

However, in the prior arts, the boat or ship as the buoyancy for leisure

obtains driving power generated by using oars, and a pedaling boat water bicycle obtaining propulsive force through the rotation of pedals has a propulsion device, which is not separately mounted but embedded in the buoyancy and has various components fixed to the buoyancy. Therefore, the propulsion device is not removable from the buoyancy and not carried. Additionally, in case of the propulsion devices patented recently, the propulsion devices have a speed changing function, but are complicated in structure and expensive in a manufacturing cost.

Furthermore, the propulsion device of the prior art is connected with high and low speed pulleys, which are formed integrally with high and low speed toothed gears, and first and second belts being in the form of a chain, so that the propulsion device cannot be easily disassembled, thereby causing frequent errors and stop of transmission of the driving power.

Disclosure of Invention Accordingly, the present invention is directed to an improved manpower propulsion device of buoyancy for leisure that substantially obviates one or more problems due to limitations and disadvantages of the related art.

It is an object of the present invention to provide an improved manpower propulsion device of a buoyancy for leisure, which is simple in structure and can rapidly transmit driving power to the buoyancy by integrally mounting the manpower propulsion device inside a body in a detachable manner, which can easily utilize a shape of the body formed in an inverted conical shape, and which can keep various tools or other articles in custody by having an auxiliary seat in rear of a driver seat and a space formed at a location, where the auxiliary seat is mounted, and exposed when the auxiliary seat is lifted.

It is another object of the present invention to provide an improved manpower propulsion device of buoyancy for leisure, which is beautiful in an external appearance.

The present invention can be changed, converted, replaced and substituted within a range of the business model, technical method and system and is not restricted in the above.

Brief Description of the Drawings Further objects and advantages of the invention can be more fully understood from the following detailed description taken in conjunction with the accompanying drawing in which: FIG. 1 illustrates a perspective view of the present invention; FIG. 2 illustrates a vertically sectional view of the present invention ; and FIG. 3 illustrates a side view of essential parts of the present invention.

Best Mode for Carrying Out the Invention The present invention will now be described in detail in connection with preferred embodiments with reference to the accompanying drawings. For reference, like reference characters designate corresponding parts throughout several views.

FIG. 1 illustrates a perspective view of the present invention, FIG. 2 illustrates a vertically sectional view of the present invention, and FIG. 3 illustrates a side view of essential parts of the present invention. Referring to the drawings, an improved manpower propulsion device of buoyancy for leisure according to the present invention will be described in detail as follows.

The manpower propulsion device of the buoyancy for leisure includes: a buoyancy 5 used as a boat or a ship and having a rudder 1; a handle 3 for adjusting a height; a handle supporter 4 mounted on a shaft tube 2 of the rudder 1 for mounting the handle 3 to the buoyancy 5; an air injection hole 6 formed in case that the buoyancy 5 is a rubber tube; an urethane rein or styrene foam 7 inserted into a

body of the buoyancy 5 in case that the buoyancy 5 is a structure made by an injection molding or an extrusion molding; a connection hole 8 formed in a central portion of the buoyancy 5; a helical gear 9, which is a manpower propulsion device, and a wire joint 10 removably inserted into the connection hole 8; a central body 11 formed in an inverted conical shape; a pair of pedals 12 formed at both sides of the central body 11 of the buoyancy 5, wherein the helical gear 9 is interlocked with the pedals 12 and operated together with the pedals 12 when the pedals 12 are rotated; a propeller 13 having a rotating section 14 on which an end of the wire joint 10 connected with the helical gear 9 is mounted; a driver seat 15 disposed on the center of the central body 11; an auxiliary seat 16 disposed in the rear of the driver seat 15 ; and a space 17 formed at a location, where the auxiliary seat 16 is formed, for keeping tools or various articles in custody, the space 17 being exposed when the auxiliary seat 16 is lifted.

When a driver seats on the driver seat 15 and steps the pedals 12 formed at the both sides of the central body 11, the helical gear 9, which is the manpower propulsion device and interlocked with the pedals 12, is rotated and the propeller 13 is also rotated because the end of the wire joint 10 connected to the helical gear 9 is mounted on the rotating section 14, and thereby the buoyancy 5 can obtain propulsive force. The buoyancy 5 moves in high or low speed propulsive force by adjusting the strength applied when the driver steps the pedals 12, so that the speed can be adjusted according to circumstances. Therefore, the present invention is simple in structure and economical because the maximum power suitable for leisure can be obtained. Because the auxiliary seat 16 is provided to the central body 11, which is formed in the inverted conical shape, two persons can ride on the buoyancy. Furthermore, the present invention provides an excellent function because the space 17 exposed when the auxiliary seat 16 is lifted allows various tools or other articles to be kept in custody inside. Moreover, the present invention has more beautiful in external appearance than the prior arts.

Additionally, the buoyancy is divided into the rubber tube and the structure injection-molded or extrusion-molded. The buoyancy of the rubber tube for a simple leisure is suitable to general users, and the buoyancy, which is injection- molded or extrusion-molded and in which urethane or styrene foam is inserted, is suitable to athletes or amusement spots in pleasure resorts. Therefore, the users can select the buoyancy according to the user's taste.

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.