WO2009035252A2

WO2009035252A2 - Apparatus for moving forward on the water

Info

Publication number: WO2009035252A2
Application number: PCT/KR2008/005323
Authority: WO
Inventors: Yong Wha Song
Original assignee: Jungwoo Family Co., Ltd
Priority date: 2007-09-10
Filing date: 2008-09-10
Publication date: 2009-03-19
Also published as: WO2009035252A3; KR20090026423A; KR100944820B1

Abstract

A water vehicle is provided. The water vehicle comprises: buoyant bodies (10) arranged parallel to and spaced a certain distance from each other; a general bicycle (20) fixedly mounted on a space between the buoyant bodies (10); a front support (30) connecting a front end of a main frame (23) of the bicycle (20) and the buoyant bodies (10) to support the bicycle (20); a rear support (40) connecting a rear end of the main frame (23) and the buoyant bodies (10) to support the bicycle (20); and a propulsion part (50) including a propeller body (52) connected to an auxiliary sprocket (27) of the bicycle (20) such that the rotation of a rear wheel (22) and sprockets of the bicycle (20) in conjunction with the rotation of pedals (24) of the bicycle (20) drives a propeller (52) of the propeller body (52). The auxiliary sprocket (27) is integrated with a rotary shaft (27a) penetrating the center of the auxiliary sprocket (27), the rotary shaft (27a) penetrates a bracket (26a) of the bicycle (20), both end portions of the rotary shaft (27a) divided by the bracket (26a) are rotatably supported by respective bearings (26b), and a power transmission cable (51) is connected to the rotary shaft (27a) of the auxiliary sprocket (27) and the propeller (52a) of the propulsion part (52) to transmit a rotational force of the auxiliary sprocket (27) to the propeller (52a). In the water vehicle, the rotary shaft of the auxiliary sprocket for gear shift positioned adjacent to the rear wheel is rotated integrally with the auxiliary sprocket and the power transmission cable is connected to the rotary shaft to rotate the propeller, so that a power can be transmitted to the propeller without any friction, thus enabling rotation of the propeller with a small force to cause no difficulty in transmitting the power to the propeller for a long time. In addition, the water vehicle uses the rotational force of the auxiliary sprocket, whose diameter is much smaller than that of a driven sprocket, to obtain a relatively high rotational speed of the propeller, resulting in a greatly increased propulsive force of the propeller.

Description

APPARATUS FOR MOVING FORWARD ON THE WATER

Technical Field

[1] The present invention relates to a water vehicle, and more specifically to a water vehicle comprising a bicycle and buoyant bodies fixedly mounted on the bicycle in which when a rider pushes pedals of the bicycle with his/her feet, a power transmission cable connected to a rotary shaft of an auxiliary sprocket, which is rotated by a chain connected to a driven sprocket of a rear wheel, rotates a propeller to generate a propulsive force, so that the water vehicle can be moved forward on water. In addition, the water vehicle comprises a control key secured to a front wheel of the bicycle in which the rider can turn a handle in the right and left directions to change the moving direction of the water vehicle.

[2]

Background Art

[3] A typical water vehicle is constructed such that a rider can drive on water using one or more buoyant bodies. Many kinds of water vehicles have been proposed, for example, a water vehicle in which a rider walks or paddles on a buoyant body to generate a propulsive force, and a water vehicle including a bicycle and a pair of buoyant bodies fixedly mounted on the bicycle in which a propulsive force is generated by a rotational force of a rear wheel resulting from the rotation of pedals to make the water vehicle move forward on water.

[4] Each of the buoyant bodies of the bicycle-type water vehicle has a long boat shape.

The buoyant bodies are arranged parallel to and spaced a certain distance from each other. The bicycle is fixedly mounted on a space between the buoyant bodies. On the other hand, Korean Registered Utility Model No. 20-0127025 discloses a water vehicle including a bicycle and a plurality of wings arranged at uniform intervals on a rear wheel of the bicycle. Further, Korean Registered Utility Model No. 20-0205702 discloses a water vehicle including a bicycle and a propeller body having a propeller wherein the propeller is moved in conjunction with a friction wheel rotating in contact with a rear wheel of the bicycle.

[5] In the prior art water vehicles, pedals are rotated to produce a rotational force, which is then transmitted to the rear wheel through a chain connected to both driving and driven sprockets. The rotation of the rear wheel allows the propeller of the propeller body to push water backwards through the wings on the rear wheel or the friction wheel in contact with the rear wheel to generate a propulsive force, which makes the water vehicle move forward. [6] In the former water vehicle, however, the rear wheel is directly rotated under a high load because the wings are directly mounted to the rear wheel. In the latter water vehicle, since the friction wheel of the propeller body is rotated in contact with the rear wheel to generate a high frictional load, a large force is required to rotate the rear wheel. Due to the high frictional load, the rider tends to become tired, which makes it impossible for him/her to enjoy playing on the water for a long time.

[7] Severe noise may be produced during the rotation of the friction wheel in contact with the rear wheel. Further, it is difficult to securely bring the friction wheel of the propeller body into contact with the rear wheel. If the friction wheel of the propeller body is not securely in contact with the rear wheel, there is the danger that the power may not be sufficiently transmitted from the rear wheel to the propeller of the propeller body, which makes it impossible to obtain a propulsive force as desired.

[8] Since the rotational force of the propeller is dependent on the ratio of the larger number of the teeth of the driven sprocket to the smaller number of the teeth of the driving sprocket, there is a limitation in increasing the number of rotations of the propeller, resulting in a reduction in the propulsive force of the propeller.

[9]

Disclosure of Invention Technical Problem

[10] The present invention has been made in an effort to solve the problems of the prior art, and it is an object of the present invention to provide a water vehicle in which a rotary shaft of an auxiliary sprocket for gear shift positioned adjacent to a rear wheel is rotated integrally with the auxiliary sprocket and a power transmission cable is connected to the rotary shaft to rotate a propeller, so that a power can be transmitted to the propeller without any friction, thus enabling rotation of the propeller with a small force to cause no difficulty in transmitting the power to the propeller for a long time.

[11] Another object of the present invention is to provide a water vehicle in which a power transmission cable is connected to a rotary shaft of an auxiliary sprocket, whose diameter is smaller than that of a driven sprocket, to rotate a propeller of a propeller body, so that a power can be stably transmitted to the propeller and a relatively high rotational speed of the propeller can be obtained, resulting in a greatly increased propulsive force of the propeller. Technical Solution

[12] In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a water vehicle comprising: buoyant bodies arranged parallel to and spaced a certain distance from each other; a bicycle fixedly mounted on a space between the buoyant bodies, and including a main frame, a pair of front and rear wheels provided in front and rear of the main frame, respectively, pedals having a driving sprocket at a center of the lower portion of the main frame, a driven sprocket connected to the driving sprocket through a chain at a center of the rear wheel, and an auxiliary sprocket connected to the driven sprocket through a chain in a bracket disposed under the driven sprocket; a front support connecting a front end of the main frame and the buoyant bodies to support the bicycle; a rear support connecting a rear end of the main frame and the buoyant bodies to support the bicycle; and a propulsion part including a propeller body connected to the auxiliary sprocket such that the rotation of the rear wheel and the sprockets in conjunction with the rotation of the pedals drives a propeller of the propeller body, wherein the auxiliary sprocket is integrated with a rotary shaft penetrating the center of the auxiliary sprocket, the rotary shaft penetrates the bracket, both end portions of the rotary shaft divided by the bracket are rotatably supported by respective bearings, and a power transmission cable is connected to the rotary shaft of the auxiliary sprocket and the propeller of the propulsion part to transmit a rotational force of the auxiliary sprocket to the propeller. [13] In an embodiment, the rotary shaft of the auxiliary sprocket is formed with a triangular, quadrangular or hexagonal recess as a polygonal recess at one end portion thereof and the power transmission cable is formed with a polygonal protrusion at one end portion thereof corresponding to the end portion of the rotary shaft such that the polygonal protrusion is fitted into and fixed to the polygonal recess.

Advantageous Effects

[14] According to the water vehicle of the present invention, the rotary shaft of the auxiliary sprocket for gear shift positioned adjacent to the rear wheel is rotated integrally with the auxiliary sprocket and the power transmission cable is connected to the rotary shaft to rotate the propeller so that a power can be transmitted to the propeller without any friction, thus enabling rotation of the propeller with a small force to cause no difficulty in transmitting the power to the propeller for a long time.

[15] In addition, the power transmission cable is connected to the rotary shaft of the auxiliary sprocket, whose diameter is smaller than that of the driven sprocket, to rotate the propeller of the propeller body so that a power can be stably transmitted to the propeller and a relatively high rotational speed of the propeller can be obtained, resulting in a greatly increased propulsive force of the propeller.

[16]

Brief Description of the Drawings

[17] In the figures:

[18] FIG. 1 is a perspective view illustrating a water vehicle according to an embodiment of the present invention; [19] FIG. 2 is a detailed perspective view illustrating a rear wheel and a propulsion part of the water vehicle of FIG. 1 ; [20] FIG. 3 is a perspective view illustrating a coupling relation between an auxiliary sprocket and a power transmission cable of the water vehicle of FIG. 1; [21] FIG. 4 is a longitudinal sectional view illustrating the auxiliary sprocket of FIG. 3;

[22] FIG. 5 is a perspective view illustrating the power transmission cable of FIG. 5;

[23] FIG. 6 is a schematic side view illustrating a propulsion part of the water vehicle of

FIG. 1;

[24] FIG. 7 is a left side view of FIG. 6;

[25] FIG. 8 is a perspective view illustrating a control key secured to a front wheel of the water vehicle of FIG. 1 ; [26] FIG. 9 is a detailed perspective view illustrating a front wheel and a handle shaft of a bicycle in the water vehicle of FIG. 1 ; [27] FIG. 10 is a perspective view illustrating a water vehicle according to another embodiment of the present invention; and [28] FIG. 11 is a perspective view illustrating another coupling relation between an auxiliary sprocket and a power transmission cable in the water vehicle of the present invention.

[29] Brief explanation of essential parts of the drawings

[30] 10: Buoyant bodies 11 : Front holding parts

[31] 11a, 12a: Clips 12: Rear holding parts

[32] 20: Bicycle 21 : Front wheel

[33] 21a: Spokes 22: Rear wheel

[34] 22a: Rear wheel shaft 23: Main frame

[35] 23a: Rear horizontal part 24: Pedals

[36] 24a: Driving sprocket 25: Chain

[37] 26: Driven sprocket 26a: Bracket

[38] 26b: Bearings 27: Auxiliary sprocket

[39] 27a: Rotary shaft 27b: Polygonal recess

[40] 28: Front wheel support frame 29: Handle

[41] 29a: Handle shaft 30: Front support

[42] 31 : Front wheel support rod 3 Ia, 41a: Latching protrusions

[43] 32: Front wheel- supporting curved rod

[44] 32a: Coupler 33: Mast pole

[45] 34: Sail 35: Mast- turning rope

[46] 40: Rear support 41 : Rear wheel support rod

[47] 42: Frame support 43: Connection rod [48] 50: Propulsion part 51 : Power transmission cable

[49] 51a: Polygonal protrusion 52: Propeller body

[50] 52a: Propeller 53: Cable protection tube

[51] 53a: Connection sockets 55: Propeller body connector

[52] 55a: Hinge 60: Lock

[53] 70: Control key 71 : Clamp

[54] 72: Upright plate

[55]

Best Mode for Carrying Out the Invention

[56] In a preferred embodiment, the water vehicle comprises a cable protection tube completely covering the power transmission cable to rotatably accommodate the power transmission cable therein and having connection sockets fastened to both ends thereof to prevent the power transmission cable from escaping from the rotary shaft into which the polygonal protrusion of the power transmission cable is fitted.

[57] In a preferred embodiment, each of the buoyant bodies includes front and rear holding parts securely holding the front and rear supports, respectively, and each of the holding parts has an upwardly open C type clip to elastically clamp the buoyant body, the open portion of the C type clip being slightly inclined forward relative to the vertical line. The reason for the forward inclination of the open portions is to surely prevent the front and rear supports from slipping off during forward movement of the water vehicle.

[58] In a preferred embodiment, the front support includes: a front wheel support rod inserted into and fixed to the C type clips of the front holding parts; and a front wheel- supporting curved rod whose one end is connected to a center of the front wheel support rod and other end is coupled and fixed to a front portion of the main frame, the front wheel- supporting curved rod being curved along the outer circumference of the front wheel.

[59] In another embodiment, the water vehicle further comprises a mast installed on the front wheel- supporting curved rod of the front support wherein the mast includes an upright mast pole, a sail extending forwardly from the upper end of the mast pole to catch a wind while turning in the right and left directions, and a mast- turning rope whose center is connected to the sail and both ends extend to a handle to turn the sail in the right and left directions.

[60] In another embodiment, the rear support includes: a U-shaped frame support whose upper ends support an auxiliary frame as a rear part of the main frame and lower ends are connected through a connection rod; and a rear wheel support rod extending horizontally from the frame support to be inserted into the C type clips of the rear holding parts on the upper surfaces of the buoyant bodies.

[61] In a preferred embodiment, the upper ends of the frame support are formed in a U configuration to allow the auxiliary frame to be seated thereon and the auxiliary frame is fixed to the frame support by fasteners to be prevented from slipping off.

[62] In another embodiment, the propeller body further includes a propeller body connector connected to a lower end of the connection rod of the rear support through a hinge so as to be thrust backward and bendable when an external force is applied to the propeller body.

[63] In a preferred embodiment, the water vehicle further comprises a lock that latches both the front wheel and the front wheel support frame to prevent the rotation of the front wheel.

[64] In a preferred embodiment, the water vehicle further comprises a control key including a clamp fastened and secured to a lower end of the front wheel, which is fixed by the lock, and an upright plate disposed under the clamp to be dipped in water.

[65]

Mode for the Invention

[66] Hereinafter, the water vehicle of the present invention will be explained in detail with reference to the accompanying drawings.

[67] As illustrated in FIGS. 1 through 9, a water vehicle according to an embodiment of the present invention comprises a pair of buoyant bodies 10, a bicycle 20 fixedly mounted on a space between the buoyant bodies 20, a front support 30 connecting a front end of a main frame 23 of the bicycle 20 and the buoyant bodies 10 to support the bicycle 20, a rear support 40 connecting a rear end of the main frame 23 and the buoyant bodies 10 to support the bicycle 20, and a propulsion part 50 for generating a propulsive force from the rotation of pedals 24.

[68] The buoyant bodies 10 are arranged parallel to and spaced a certain distance from each other. Each of the buoyant bodies 10 has a long tubular shape. A pair of front holding parts 11 are disposed on the upper surfaces of the respective buoyant bodies 10 corresponding to the front of a front wheel 21 and a pair of rear holding parts 12 are disposed on the upper surfaces of the respective buoyant bodies 10 under a rear wheel 22. Each of the front holding parts 11 has an upwardly open 'C type clip 11a into which the front support 30 is inserted in the transverse direction, and each of the rear holding parts 12 has an upwardly open 'C type clip 12a into which the rear support 30 is inserted in the transverse direction.

[69] In a preferred embodiment, the open portions of the 'C type clips 11a are somewhat inclined forward relative to the respective vertical lines. The reason for the forward inclination of the open portions is to surely prevent the front and rear supports from slipping off during forward movement of the water vehicle.

[70] The bicycle 20 is positioned on a space between the buoyant bodies 20. In the bicycle

20, front and rear wheels 21 and 22, each having a plurality of spokes radially arranged from the center thereof, are provided in front and rear of the main frame 23, respectively, pedals 24 having a driving sprocket 24a are installed at a center of the lower portion of the main frame 23, a driven sprocket 26 is provided at a rear wheel shaft 22a of the rear wheel 22 and is connected to the driving sprocket 24a through a chain 25, and an auxiliary sprocket 27 integrated with a rotary shaft 27 a is rotatably installed in a bracket 26a disposed under the driven sprocket 26. The main frame 23 has a rear horizontal part 23a to support the rear wheel shaft 22a of the rear wheel 22. The rear horizontal part 23a is supported by the rear support 40.

[71] Herein, the central rotary shaft 27a of the auxiliary sprocket 27 is installed so as to penetrate the bracket 26a. Both end portions of the rotary shaft 27a divided by the bracket 26a are rotatably supported by respective bearings 26b, and a rotational force of the auxiliary sprocket 27 is transmitted to a propeller 52a of the propulsion part 50 through a power transmission cable 51 connected to the rotary shaft 27a of the auxiliary sprocket 27.

[72] The rotary shaft 27a of the auxiliary sprocket 27 has a polygonal recess 27b at one end portion thereof, and the power transmission cable 51 has a polygonal protrusion 51a at one end portion thereof corresponding to the end portion of the rotary shaft 27 a. The polygonal protrusion 51a is fitted into and fixed to the polygonal recess 27b. The polygonal recess 27b and the polygonal protrusion 51a may have any shape so long as the rotary shaft 27a is coupled to the power transmission cable 51. For example, as illustrated in FIG. 11, a circular recess 27c is formed at one end portion of the rotary shaft 27 a and a circular protrusion 51b is formed at one end portion of the power transmission cable 51, the circular recess 27c and the circular protrusion 51b having a latching protrusion 27d and a latching recess 51c, respectively, to prevent the rotary shaft 27a and the power transmission cable 51 from being rotatably unengaged with each other on the contact surface between the circular recess 27c and the circular protrusion 51b.

[73] The front support 30 connects a front end of the main frame 23 and the buoyant bodies to support the bicycle 20. The front support 30 includes a long rod-shaped front wheel support rod 31 inserted into the C type clips 1 Ia of the front holding parts 11 and a front wheel- supporting curved rod 32 whose one end is connected to a center of the front wheel support rod 31 and other end is coupled and fixed to a handle shaft 29a at a front portion of the main frame 23, the front wheel- supporting curved rod 23 being curved along the outer circumference of the front wheel 21 till the handle shaft 29a.

[74] The front wheel support rod 31 has latching protrusions 3 Ia at both ends thereof to prevent the buoyant bodies 10 from slipping off while being moved further away from each other in the width direction. The front wheel-supporting curved rod 32 coupled to the main frame 23 is provided with a detachable coupler 32a surrounding the outer surface of the handle shaft 29a at one end thereof.

[75] The rear support 40 connects the rear horizontal part 23a of the main frame 23 and the buoyant bodies to support the bicycle 20. The rear support 40 includes a U-shaped frame support 42 whose upper ends support the rear horizontal part 23a of the main frame 23 and lower ends are connected through a connection rod 43, and a rear wheel support rod 41 extending horizontally from the frame support 42 to be inserted into the C type clips 12a of the rear holding parts 12 on the upper surfaces of the buoyant bodies 10.

[76] In a preferred embodiment, the upper ends of the frame support 42 are formed in a U configuration to allow the rear horizontal part 23a to be seated thereon and the rear horizontal part 23a is fixed to the frame support 42 by fasteners to be prevented from slipping off. The rear wheel support rod 41 has latching protrusions 41a at both ends thereof to prevent the buoyant bodies 10 from slipping off while being moved further away from each other in the width direction.

[77] The propulsion part 50 includes a propeller body 52 connected to a lower end of the connection rod 43 of the rear support 40.

[78] The propulsion part 50 is positioned under the rear support 40 and the propeller 52a of the propeller body 52 generates a propulsive force. The power transmission cable 51 extends from the rotary shaft 27a of the auxiliary sprocket 27 till the propeller 52a of the propeller body 52, and is made of a flexible material.

[79] The propeller body 52 further includes a propeller body connector 55 connected to a lower end of the connection rod 43 of the rear support 40 through a hinge 55. When the propeller body 52 comes into contact with an obstacle during forward movement, it is thrust backward and bendable through the hinge 55a. The hinge 55a may have a torsion spring as means for returning the backwardly bent propeller body connector 55 to its original position.

[80] The polygonal protrusion 51a formed at one end portion of the power transmission cable 51 is fitted into and fixed to the polygonal recess 27b formed at one end portion of the rotary shaft 27 a of the auxiliary sprocket 27. The water vehicle comprises a cable protection tube 53 completely covering the power transmission cable 51 and having connection sockets 53a fastened to both ends thereof while accommodating polygonal protrusions formed at both ends of the power transmission cable 51.

[81] The water vehicle further comprises a lock 60 as a quadrangular frame that latches a front wheel support frame 28 and spokes 21a of the front wheel 21 to fix the front wheel 21 to the front wheel support frame 28. One edge of the quadrangular frame is hingedly connected and another edge thereof is separably connected such that one side of the lock 60 can be opened/closed.

[82] The water vehicle further comprises a control key 70 secured to a lower end of the front wheel 21, which is fixed by the lock 60, and including a clamp 71 fastened and secured to the front wheel 21 as an upper part and an upright plate 72 dipped in water as a lower part.

[83] Due to this construction, a user disassembles the water vehicle and can ride the bicycle 20 while carrying the buoyant bodies 10, the front support 30, the rear support 40, the propulsion part 50 and the other parts with his/her bag or knapsack. The user can assemble the parts with the bicycle 20 to construct the water vehicle.

[84] The following assembly procedure of the water vehicle is provided to assist in a further understanding of the present invention. First, the buoyant bodies 10 are properly filled with air using a pump and arranged parallel to each other. The front and rear supports 30 and 40 are installed on the front and rear portions of the buoyant bodies 40.

[85] Specifically, the front wheel support rod 31 of the front support 30 is seated on the C type clips 1 Ia of the front holding parts 11 of the buoyant bodies 11, and the coupler 32a positioned on the upper end of the front wheel-supporting curved rod 32 of the front support 30 is fixedly coupled to the handle shaft 29a positioned in front of the main frame 23 so as to surround the outer surface of the handle shaft 29a. At this time, the latching protrusions 31a formed at both ends of the front wheel support rod 31 are latched by the outer ends of the C type clips 1 Ia to prevent the buoyant bodies 10 from slipping off both ends of the front wheel support rod 31.

[86] The rear wheel support rod 41 of the rear support 40 is seated on the C type clips 12a of the rear holding part 12 of the buoyant bodies 10, and the frame support 42 of the rear support 40 is fixedly coupled to and supports the rear horizontal part 23a. At this time, the latching protrusions 41a formed at both ends of the rear wheel support rod 41 are latched by the outer ends of the C type clips 21a to prevent the buoyant bodies 10 from slipping off both ends of the rear wheel support rod 41.

[87] Thereafter, the bicycle 20 is firmly installed on the buoyant bodies 10 through the front and rear supports 30 and 40, and the power transmission cable 51 is connected to the propeller 52a of the propulsion part 50 and the rotary shaft 27a of the auxiliary sprocket 27.

[88] The connection procedure of the power transmission cable 51 is as follows. The polygonal protrusion 51a formed at one end of the power transmission cable 51 is fitted into and fixed to the polygonal recess 27b formed at one end of the rotary shaft 27a of the auxiliary sprocket 27, and one of the connection sockets 53a of the cable protection tube 53 is fastened to the bracket 26a disposed on the outer surface of the rotary shaft 27a to prevent the polygonal protrusion 51a of the power transmission cable 51 from slipping off the rotary shaft 27a of the auxiliary sprocket 27.

[89] Further, the polygonal protrusion 51a formed at the other end of the power transmission cable 51 is fitted into and fixed to a polygonal recess (not shown) formed at the distal end of the propeller 52a of the propeller body 52 and the other connection socket 53a of the cable protection tube 53 is fastened to the propeller body 52 to prevent the polygonal protrusion 51a of the power transmission cable 51 from slipping off the propeller 52a of the propeller body 52.

[90] After the assembly of the water vehicle, when the rider pushes the pedals 24 with his/ her feet on the bicycle 20, the rear wheel 22 is rotated because the driving sprocket 24a is connected to the driven sprocket 25 and the auxiliary sprocket 27 of the rear wheel 22 through the chain 25. As a result, the auxiliary sprocket 27 whose number of teeth is relatively small is rotated at a high speed when compared to the rotational speed of the rear wheel 22.

[91] The rotary shaft 27a integrated with the auxiliary sprocket 27 is rotated at the same speed as the auxiliary sprocket 27, and finally, the propeller 52a of the propeller body 52 is also rotated at a high speed through the power transmission cable 51 connected to the rotary shaft 27a to generate a propulsive force. The auxiliary sprocket 27 can be sufficiently driven by an external driving force of the driving and the driven sprockets 24a and 26 without any contact (i.e. friction) with the rear wheel 22. In conclusion, the propeller 52a can be continuously driven with a small force without causing any difficulty for a long time.

[92] During forward movement of the water vehicle by the propulsive force generated from the propeller 52a of the propeller body 52, the rider can freely turn a handle 29 of the bicycle 20 in the right and left directions to change the moving direction of the water vehicle. At this time, since the front wheel support frame 28 and the spokes 21a of the front wheel 21 are latched by the lock 60 to prevent the front wheel 21 from being rotated, the upright plate 72 of the control key 70, which is secured to a lower end of the front wheel 21 so as to be turned integrally with the turning of the handle in the right or left direction, is turned in the same direction as the handle to change the moving direction of the water vehicle.

[93] When the propeller body 52 of the propulsion part 50 comes into contact with a submerged rock or the water bottom during forward movement of the water vehicle, the propeller body 52 is pushed back and bent upwardly with respect to the hinge 55a of the propeller body connector 55 to be protected from damage resulting from the pressurization of the unexpected external force, and as a result, the rider can continue to drive.

[94] The user of the water vehicle can enjoy driving on the water. After disassembly, the user can ride the bicycle to enjoy cycling on the road while carrying the other parts with a bag.

[95] FIG. 10 is a view illustrating a water vehicle according to another embodiment of the present invention. The water vehicle of FIG. 10 is distinguished from the previous embodiment in that it further comprises a mast installed on the front wheel- supporting curved rod 32 of the front support 30. The mast includes an upright mast pole 33, a sail 34 extending forwardly from the upper end of the mast pole 33 to catch a wind while turning in the right and left directions, and a mast-turning rope 34 whose center is connected to the sail 34 and both ends extend to the handle 29 to turn the sail 34 in the right and left directions.

[96] The water vehicle is suitable for use on a windy day. The rider rides on the bicycle

20 and pulls the mast-turning rope 35 on the handle to allow the sail 34 to catch a wind while rotating in the right and left directions. Due to this steering activity, an additional propulsive force can be produced to some extent and the moving direction of the water vehicle can be changed.

[97]

Industrial Applicability

[98] As apparent from the foregoing, a user can ride the bicycle to enjoy cycling on the road at ordinary times and enjoy playing on the water vehicle in the river or lake. Therefore, the water vehicle of the present invention can be useful in the leisure and sport applications.

[99]

Claims

[ 1 ] A water vehicle , comprising : buoyant bodies arranged parallel to and spaced a certain distance from each other; a bicycle fixedly mounted on a space between the buoyant bodies, and including a main frame, a pair of front and rear wheels provided in front and rear of the main frame, respectively, pedals having a driving sprocket at a center of the lower portion of the main frame, a driven sprocket connected to the driving sprocket through a chain at a center of the rear wheel, and an auxiliary sprocket connected to the driven sprocket through a chain in a bracket disposed under the driven sprocket; a front support connecting a front end of the main frame and the buoyant bodies to support the bicycle; a rear support connecting a rear end of the main frame and the buoyant bodies to support the bicycle; and a propulsion part including a propeller body connected to the auxiliary sprocket such that the rotation of the rear wheel and the sprockets in conjunction with the rotation of the pedals drives a propeller of the propeller body, wherein the auxiliary sprocket is integrated with a rotary shaft penetrating the center of the auxiliary sprocket, the rotary shaft penetrates the bracket, both end portions of the rotary shaft divided by the bracket are rotatably supported by respective bearings, and a power transmission cable is connected to the rotary shaft of the auxiliary sprocket and the propeller of the propulsion part to transmit a rotational force of the auxiliary sprocket to the propeller.

[2] The water vehicle according to claim 1, wherein the rotary shaft of the auxiliary sprocket is formed with a polygonal recess at one end portion thereof and the power transmission cable is formed with a polygonal protrusion at one end portion thereof corresponding to the end portion of the rotary shaft such that the polygonal protrusion is fitted into and fixed to the polygonal recess.

[3] The water vehicle according to claim 2, wherein the water vehicle comprises a cable protection tube completely covering the power transmission cable to rotatably accommodate the power transmission cable therein and having connection sockets fastened to both ends thereof to prevent the power transmission cable from escaping from the rotary shaft into which the polygonal protrusion of the power transmission cable is fitted.

[4] The water vehicle according to claim 2, wherein the polygonal recess and the polygonal protrusion have a triangular, quadrangular or hexagonal shape in cross section.

[5] The water vehicle according to claim 1, wherein the rotary shaft of the auxiliary sprocket is formed with a circular recess at one end portion thereof, the power transmission cable is formed with a circular protrusion at one end portion thereof corresponding to the end portion of the rotary shaft such that the circular protrusion is fitted into the circular recess, and latch structures whose shapes correspond to each other are formed on the contact surfaces of the circular recess and the circular protrusion.

[6] The water vehicle according to claim 1, wherein the front support includes: a front wheel support rod inserted into and fixed to C type clips of front holding parts; and a front wheel- supporting curved rod whose one end is connected to a center of the front wheel support rod and other end is coupled and fixed to a front portion of the main frame, the front wheel-supporting curved rod being curved along the outer circumference of the front wheel

[7] The water vehicle according to claim 6, further comprising a mast installed on the front wheel-supporting curved rod of the front support wherein the mast includes an upright mast pole, a sail extending forwardly from the upper end of the mast pole to catch a wind while turning in the right and left directions, and a mast-turning rope whose center is connected to the sail and both ends extend to a handle to turn the sail in the right and left directions.

[8] The water vehicle according to claim 1, wherein the rear support includes a U- shaped frame support whose upper ends support a rear horizontal part of the main frame and lower ends are connected through a connection rod; and a rear wheel support rod extending horizontally from the frame support to be inserted into C type clips of rear holding parts on the upper surfaces of the buoyant bodies.

[9] The water vehicle according to claim 1, wherein the propeller body further includes a propeller body connector connected to a lower end of a connection rod of the rear support through a hinge so as to be thrust backward and bendable.

[10] The water vehicle according to claim 1, further comprising a lock that latches both the front wheel and a front wheel support frame to prevent the rotation of the front wheel.

[11] The water vehicle according to claim 10, further comprising a control key including a clamp fastened and secured to a lower end of the front wheel, which is fixed by the lock, and an upright plate disposed under the clamp to be dipped in water.