WO2007139356A1

WO2007139356A1 - A skate board

Info

Publication number: WO2007139356A1
Application number: PCT/KR2007/002634
Authority: WO
Inventors: Kyung Nam Shin; Seong Won Moon
Original assignee: Kyung Nam Shin; Seong Won Moon
Priority date: 2006-05-30
Filing date: 2007-05-30
Publication date: 2007-12-06

Abstract

A skateboard is provided for skating only using both feet which are placed on different decks. A propellant force for skating is generated from a lower portion of one deck, so that the positive transmission of force is carried out.

Description

Description A SKATE BOARD

Technical Field

[1] The present invention relates to a skateboard, in which two decks spaced apart from each other are coupled by a joint shaft, and have directional casters mounted thereunder; the directional casters pinch to cause the decks to move forward or backward when the decks are turned; the joint shaft is mounted under the decks so as to be rotated in a clockwise or counterclockwise direction without twisting, and is provided with retaining brackets so as to be prevented from escaping from the decks at opposite ends thereof; the retaining brackets are surrounded by rubber blocks; the rubber blocks are pressed and restored elastically while the joint shaft is rotated in the clockwise or counterclockwise direction when the decks are turned, thereby providing easy turning of the decks and positive transmission of force. Background Art

[2] Currently, such a skateboard used for skating is designed to couple separated decks using a joint member exerting twisting to enable turning of the decks, and to allow a propellant force when the decks are turned to be generated by pitching of directional casters mounted under the decks.

[3] Thus, in order to guarantee this turning of the decks, the joint member coupling the separated decks must exert the twisting. Thus, the twisting force of the joint member, the turning, and the pitching are important.

[4] In the event that the pitching occurs, the decks have difficulty in obtaining a propellant force. There occur various problems due to choice of a material that is not damaged by repetitive twisting in order to provide twisting and restoration when the decks are turned, and the dimensions such as thickness and length, and so on.

[5] Due to these problems, the cost of production is increased. Further, due to residual stress or fatigue strength caused by long-term use, the joint member exerting the twisting is damaged or undergoes remarkable reduction in strength.

[6] Further, the joint member exerting the twisting must be fixed under the decks. To this end, a separate fixing unit is required, which makes it difficult to produce the skateboard.

[7] Furthermore, the twisting mainly occurs in the middle of the joint member, and thus the transmission of force caused by the turning of the decks occurs in the front or rear of the decks rather than lower portions of the decks, so that the positive transmission of force is impossible.

[8] In order to prevent the joint member from pitching, the joint member must be provided therearound with a separate protective pipe. Thereby, the cost of production is increased.

[9] Accordingly, the present invention is to provide a skateboard capable of ensuring positive transmission of force, reducing the cost of production, and providing easy manipulation. To this end, a short joint shaft free of twisting is used as a joint shaft coupling two separated decks, and is provided with retaining brackets at opposite ends thereof in order to be fixed to a tail of one deck and a nose of the other deck. The retaining brackets are surrounded by rubber blocks having an elastic force. The rubber blocks are received into holders mounted under the decks so as to prevent the rubber blocks from being loose.

[10] Thus, when one of the decks is turned, the rubber block of the turned deck exerts the elastic force to the retaining bracket of the turned deck. Therefore, the joint shaft is rotated, and the twisting is transmitted to the other deck. Thereby, the decks move forward or backward.

[11] Further, because the joint shaft itself exerts no twisting, and because the elastic force is generated from a lower portion of the turned deck, the positive transmission of force occurs. Further, the use of the short joint shaft and the rubber blocks can reduce the cost of production.

[12] In addition, each directional caster is mounted under each deck so as to have the same inclination in the same direction, and the joint shaft is mounted on the tail of one deck and the nose of the other deck, so that trucks of the directional casters are formed so as to have the inclination corresponding to the direction casters, unlike the related art in which the respective decks are molded by different molding units (molds) due to different mounted positions of wheels of the directional casters. Thereby, only the mounted positions of the directional casters are changed in the decks produced by a single type of molding unit, so that the skateboard can be provided at an inexpensive price.

Disclosure of Invention Technical Problem

[13] Accordingly, the present invention has been made in an effort to solve the problems that a leaf spring or an elastic rod is twisted to cause pitching of the decks when the decks are turned, that this leaf spring or elastic rod is not easily twisted in the case of a short length, that an inserting part is formed at a great length in order to fix this leaf spring or elastic rod in the case in which this leaf spring or elastic rod is long, and that positive propulsion is not impossible because the force caused by restoration after twisting is dispersed in a direction perpendicular to a twisting axis when transmitted. Technical Solution [14] In order to solve these problems, according to an aspect of the present invention, there is provided a skateboard for ensuring positive transmission of force by performing only turning without pitching and generating twisting only from a lower portion of each deck, in which a short joint shaft is rotatably mounted under a tail of one deck and a nose of the other deck, is provided with retaining brackets at opposite ends thereof; the retaining brackets are surrounded by rubber blocks having elasticity; and the rubber blocks are received in holders installed under the tail of one deck and the nose of the other deck so as not to be loose.

Advantageous Effects

[15] According to the present invention, the skateboard can be skated forward or backward only using both feet which are placed on different decks. The propellant force for skating is generated from the lower portion of each deck, so that the positive transmission of force is carried out. Brief Description of the Drawings

[16] <Description of symbols of the main parts in the drawings>

[17] 10, 20: deck 11: holder

[18] 12: guide rail 13: flange

[19] 14: groove 15: support

[20] 16: truck

[21] 30: joint shaft 31 : retaining bracket

[22] 32: auxiliary shaft 33: spacer shaft

[23] 34: retaining groove

[24] 40, 40a: rubber block 41 : C-shaped slot

[25] 42: damping hole 43: positioning step

[26] 50: caster 51 : bracket

[27] 52: wheel

[28] 100, 100a: deck 110, 210: joint shaft recess

[29] 120, 220: retaining groove 130, 230: rubber block recess

[30] 140, 240: pivoting auxiliary flange

[31] 150: support wall 160: fixing recess

[32] 170: truck 200: cap

[33] 250: step 260: inserted shoulders

[34] 300: joint shaft 310: flange

[35] 320: groove 330: joint shaft through-hole

[36] 340: retaining shaft

[37] 400, 400a: rubber block 410: hole

[38] 500: caster 510: wheel [39] 520: bracket

Best Mode for Carrying Out the Invention

[40] FIGS. 1 and 2 illustrate coupling configuration of a joint shaft according to an embodiment of the present invention. In a skateboard of the present invention, front and rear decks 10 and 20, which are spaced apart from each other by a predetermined distance, are interconnected by a short joint shaft 30. The joint shaft 30 is provided with retaining retaining brackets 31 on opposite ends thereof. The retaining brackets 31 are installed in holders 11, each of which has a width greater than that of each retaining bracket 31. At this time, the retaining brackets 31 can rotate within a predetermined range when rotating to the left or right in the holders 11.

[41] At this time, the retaining brackets 31 stand apart from the holders 11. In this state, the joint shaft 30 is rotated within a predetermined range in a clockwise or counterclockwise direction.

[42] Further, the retaining brackets 31 are surrounded by the rubber blocks 40 so as to be elastically moved. In this state, the rubber blocks 40 are received in the holders 11, which are mounted on a tail of the front deck 10 and a nose of the rear deck 20 respectively, so as not to be loose.

[43] Further, after the rubber blocks 40 are received in the holders 11, the holders 11 are fixed to the decks 10 and 20 by holder caps 1 Ia using screws, etc. such that the rubber blocks 40 do not escape from the holders 11.

[44] The holders 11 are spaced apart from guide rails 12 in the front thereof. The guide rails 12 function not only to prevent the retaining brackets 31 of the joint shaft 30 from escaping but also help the joint shaft 30 rotate easily. Each guide rail 12 is provided with a flange 13 at one end thereof. These flanges 13 serve not only to increase contact areas with the retaining brackets 31 but also separate the joint shaft 30 from the guide rails 12 at a predetermined distance so as to reduce the resistance when the joint shaft 30 rotates in the clockwise or counterclockwise direction.

[45] Further, in the event that the joint shaft 30 having a small diameter is used to reduce the cost of production, an auxiliary shaft 32 shorter than the joint shaft 30 is fitted around the joint shaft 30 in order to reinforce the joint shaft 30 and induce the joint shaft 30 to rotate easily, and then is fixed by fixing pins 32a. In this manner, because the auxiliary shaft 32 shorter than the joint shaft 30 is fitted and fixed, retaining grooves 34 are defined between the retaining brackets 31 and the auxiliary shaft 32. The flanges 13 protruding from the ends of the guide rails 12 are rotatably inserted into the retaining grooves 34. Thereby, the auxiliary shaft 32 is rested in the guide rails 12. Because the flanges 13 are inserted into the retaining grooves 34, the joint shaft 30 does not pitch during rotation. As a result, the joint shaft 30 is maintained linearly without inclination, and thus performs easy rotation.

[46] As described above, the retaining brackets 31 are prevented from escaping by the guide rails 12, and simultaneously the flanges 13 are rotatably inserted into the retaining grooves 34 defined by the shot auxiliary shaft 32 fitted around the joint shaft 30. This dual safety structure is provided for preventing the joint shaft 30 from escaping.

[47] As illustrated in FIG. 4, the holder caps l la are provided with guide rails 1 Ib coming into contact with the guide rails under the tail of the front deck and the nose of the rear deck, as well as flanges 13.

[48] Further, as illustrated in FIGS. 1 and 2, a spacer shaft 33 is rotatably fitted around the auxiliary shaft 32. Thus, only the spacer shaft 33 is exposed outside between the decks 10 and 20.

[49] The retaining brackets 31 connected to the joint shaft 30 have a "C" shape, and the rubber blocks 40 surrounding the retaining brackets 31 are provided with "C" slots 41 so as to correspond to the C shape of the retaining brackets 31.

[50] Meanwhile, in order to fix the C-shaped retaining brackets 31 to the joint shaft 30, the joint shaft 30 is provided with angled projections 30a, and middle parts 31a of the retaining brackets 31 are provided with angled holes 31b. Thus, the angled projections 30a are inserted into the angled holes 31b, and then are fixed by welding.

[51] Further, in the state in which the rubber blocks 40 and 40a are each bisected to completely surround the retaining brackets 31, the rubber blocks 40 and 40a are received in the holders 11 under the tail of the first deck 10 and the nose of the rear deck 20, and then are firmly fixed by the holder caps l la.

[52] In order to more firmly fix the rubber blocks 40 and 40a, the holders 11 of the decks

10 and 20 are provided with spaces 14 at a predetermined height. Accordingly, the rubber blocks 40 and 40a are primarily inserted into the spaces 14, so that they can be firmly and stably fixed.

[53] Further, the rubber blocks 40 and 40a are provided with damping holes 42 between lateral parts of the C-shaped slots 41 thereof such that the rubber blocks 40 and 40a are easily contracted and expanded when external force is applied to the rubber blocks 40 and 40a into which the C-shaped retaining brackets 31 are inserted. In addition, the rubber blocks 40 and 40a are provided with positioning steps 43 such that the middle parts 31a of the retaining brackets 31 are placed on the positioning steps 43.

[54] Meanwhile, each of the decks 10 and 20 is provided with a plurality of trucks 16 for mounting casters 50 on the bottom surface thereof. In the event that the skateboard is assembled using the decks injection-molded in the same type, the casters 50 are mounted at different positions. Thereby, the cost of the skateboard is reduced, and the productivity of the skateboard is increased. [55] In order to prevent the nose of the front deck 10 and the tail of the rear deck 20 from being contacted with the ground surface when the decks 10 and 20 are turned or carved, each of the decks 10 and 20 is provided with detachable supports 15. Accordingly, these detachable supports 15 prevent the decks 10 and 20 from being contacted with the ground surface when the decks 10 and 20 are turned.

[56] As described above, the retaining brackets 31 coupled to the opposite ends of the joint shaft 30 connecting the decks 10 and 20 are surround by the rubber blocks 40 and 40a, and the rubber blocks 40 and 40a are received in the holders 11 under the tail of the front deck and the nose of the rear deck, and are fixed by the holder caps 11a. Thus, when any one of the decks 10 and 20 is turned, propellant force is generated by the directional caster of one board. In this state, one of the rubber blocks 40 and 40a is pressed at the same time, and the joint shaft 30 is rotated. Thus, the other deck is easily turned.

[57] In other words, when the rubber block 40 mounted under the tail of the turned deck

10 is pressed due to such turning, the other deck 20 shows a tendency to move forward without turning. At this time, the directional caster of the front deck pitches to generate the propellant force due to the turning of the front deck 10. Due to this turning, the joint shaft is rotated, and thus the rubber block 40 is pressed. Then, the pressed rubber block 40 is smoothly restored to ensure the easy turning. This restoring force is intactly transmitted to the other deck 20 through the joint shaft, so that the other deck can be turned.

[58] In this manner, the propellant force generated by the directional caster due to the turning of the front deck makes easy turning possible together with the elastic force of the rubber block 40 mounted under the tail of the front deck 10. Thus, the joint shaft 30 is induced to be rotated in the clockwise or counterclockwise direction. Further, the turning force for the propellant force is generated from the lower portion of the deck 10, so that the positive transmission of force is possible. Furthermore, the joint shaft 30 is not twisted, and thus no pitching occurs during the turning. Further, the elastic force of the rubber block 40 is generated only by the joint shaft 30 under the front deck 10, so that the stable transmission of force is possible without slight pitching of the front deck when the front deck is turned.

[59] At this time, the directional casters 50 mounted on the bottom surface of the decks

10 and 20 are available from the market. Each directional caster 50 is designed so that a wheel 52 is mounted on a bracket 51 inclined in one direction so as to be able to freely rotated, and that the bracket 51 is mounted on the truck 16 inclined in one direction so as to be able to be freely rotated.

[60] Further, in the present invention, the retaining brackets 31 of the joint shaft 30 have been described as an assembled type. However, the retaining brackets 31 may be an integral type, which does not depart from the scope and spirit of the present invention.

[61] The joint shaft 30 are mounted to the tail of the front deck 10 and the nose of the rear deck 20 without twisting, so that the decks 10 and 20 can be turned without upward and downward pitching. Because the brackets 51 having a predetermined inclination are rotatably mounted on the trucks 16, the front deck 10 is turned to the left or right side while the bracket 51 of the directional caster 50 is pitched leftward or rightward about the truck 16. Due to this leftward or rightward turning, the rubber block 40 is repetitively contracted or expanded in the retaining bracket 31 of the joint shaft 30 under the front deck 10, and thus the elastic force of the rubber block 40 is transmitted to the joint shaft 30 that is integrally coupled with the retaining bracket 31. Thereby, the joint shaft 30 is rotated, and the elastic force is transmitted to the rear deck 20. As a result, the front deck 10 gets the propellant force, so that it can be skated at a rapid speed.

[62] At this time, the force generating the propellant force is generated from the lower portion of the front deck, causes the joint shaft 30 to be rotated, and is intactly transmitted to the lower portion of the rear deck. Thus, due to the positive transmission of force and the elastic motion such as the contraction or expansion occurring at a fixed position, the decks can be operated reliably.

[63] FIGS. 5 through 13 illustrate another embodiment of the present invention. As illustrated in FIGS. 5 and 6, front and rear decks 100 and 100a, which are spaced apart from each other by a predetermined distance, are provided thereunder with trucks 170, having a predetermined inclination, on each of which a directional caster 500 having a wheel 510 mounted rotatably on a bracket 520 having a predetermined inclination is rotatably mounted. These separated decks 100 and 100a are coupled by a joint shaft 300, which is prevented from escaping and can be rotated in a clockwise or counterclockwise direction, between a tail of the front deck and a nose of the rear deck.

[64] At this time, in order not only to prevent the joint shaft 300 from escaping but also enable the joint shaft 300 to be rotated in the clockwise or counterclockwise direction, the joint shaft 300 is provided with grooves 320 and flanges 310 in front of the grooves 320. Further, each deck is provided with a joint shaft recess 110 in which the joint shaft 300 is placed, a pivoting auxiliary flange 140 that is located at an inner end of the joint shaft recess 110, is inserted into the groove 320, and assists the joint shaft to be retained and pivoted, and a retaining groove 120 that is located on one side of the pivoting auxiliary flange 140. Then, the flanges of the joint shaft are inserted into the retaining grooves 120 of the decks, and simultaneously the pivoting auxiliary flanges 140 of the decks are inserted into the grooves of the joint shaft. Thereby, the joint shaft 300 can be prevented from escaping in a backward direction, and simultaneously be easily rotated in the clockwise or counterclockwise direction. [65] As illustrated in FIG. 12, the pivoting auxiliary flanges 140 of the decks cause the joint shaft 300 to be slightly spaced apart from the joint shaft recesses 110 due to the height thereof when inserted into the grooves of the joint shaft, so that they allow the joint shaft to be rotated in the clockwise or counterclockwise direction with minimum frictional resistance. In order to stably maintain this spaced state, an outer end and lateral edges 110b of each joint shaft recess 110 are provided with pivoting auxiliary flanges 140a, wherein the lateral edges 110b cause the joint shaft 300 to be exposed when the joint shaft 300 is placed in the joint shaft recesses 110 of the decks 100 and 100a.

[66] Further, in order to positively regulate the clockwise or counterclockwise rotation of the joint shaft and simultaneously facilitate turning of the decks 100 and 100a, the joint shaft 300 is provided with retaining shafts 340, each of which protrudes in opposite directions, at opposite ends thereof, and the protruding shafts 340 are fixed to the joint shaft 300 by welding or screwing. Alternatively, the joint shaft 300 may be provided with joint shaft through-holes 330. Then, the retaining shafts 340 pass through the joint shaft through-holes 330 and are welded, or are pressure-fitted into the joint shaft through-holes 330.

[67] In the present invention, after the joint shaft through-holes 330 are formed so as to transversely pass through the joint shaft 300 made of a hollow pipe, the retaining shafts 340 are fixed so as to protrude from the hollow joint shaft 300 by pressure-fitting.

[68] Further, the protruding retaining shafts 340 are detachably coupled with rubber blocks 400, each of which is provided with a blind hole 410. In the event that each rubber block 400 is provided with a through-hole, the same effect can be accomplished.

[69] As illustrated in figures, this joint shaft 300 comes into close contact with the joint shaft recesses 110 and rubber block recesses 130 of the decks 100 and 100a when inserted. In this state, caps 200, which are provided with joint shaft recesses 210 and rubber block recesses 220 having the same structures as the joint shaft recesses 110 and rubber block recesses 130 of the decks 100 and 100a, are covered and fixed by fastening means such as screws.

[70] At this time, this fastening means ensures firm fastening force by strong screwing, and easy repairing by unfastening.

[71] Further, in order to maintain stability in the state in which the caps 200 are coupled to the decks 100 and 100a, the decks 100 and 100a are provided with fixing recesses 160, and the caps 200 are provided with inserted shoulders 260 so as to be able to be inserted into the fixing recesses 160. Thereby, the caps 200 are fixed to the decks by the fastening means.

[72] Further, the decks 100 and 100a are provided with support walls 150 at a pre- determined height at the parts where the joint shaft recesses 110 and rubber block recesses 130 thereof are formed. The caps 200 are provided with steps 250 so as to be engaged with the support walls 150. In the engaged state, the caps 200 are prevented from being damaged when the rubber blocks 400 are pressed by the turning of the decks 100 and 100a.

[73] These support walls 150 are to take into consideration a diameter of the joint shaft

300 by calculation of a load generated when the decks are turned, and simultaneously to prevent the decks 100 and 100a from being thickened, so that they can reduce the cost of production and improve productivity by reducing a time for injection molding. Further, the support walls 150 can increase the coupling with the caps 200.

[74] Accordingly, because the rubber blocks 400 for elastic restoration when the decks

100 and 100a are coupled only to the retaining shafts 340, the rubber blocks 400 can be elastically restored with little force. When the propellant force is generated by the leftward or rightward turning of the front deck, easy erection of a rider and easy leftward or rightward turning of the front deck are ensured. Further, because the rubber blocks pressed when the front deck is turned are smoothly restored, reliable operation is provided.

[75] This elastically restoring force is generated from the lower portion of the front deck

100 when the front deck is turned, causes the joint shaft 300 to be rotated in the clockwise or counterclockwise direction, and is transmitted to the lower portion of the rear deck without a loss. Thus, the positive transmission of force is possible. The rubber blocks 400 are elastically contracted or expanded under the tail of the front deck 100 and the nose of the rear deck 100a, the reliable operation is possible. Because the rubber blocks 400 surround only the retaining shafts of the joint shaft, they can be easily restored, so that the skateboard is suitable for children, the old, or the weak. Mode for the Invention

[76] According to the present invention, the front and rear decks that are separated from each other are coupled by the joint shaft that is prevented from escaping in a forward direction and is rotated in the clockwise or counterclockwise direction within a predetermined range, and then the propellant force is generated by the directional caster mounted under the front desk when the front desk is turned. In this case, in order to allow the front desk to be smoothly and easily turned, the opposite ends of the joint shaft are provided with the brackets so as to be prevented from escaping, and the brackets are surrounded by the rubber blocks. Thereby, when the propellant force is generated by the directional caster when the front desk is turned, the easy turning for the reliable operation is provided, and the convenient turning is provided.

[77] Further, when a weak elastic force is required when the front board is turned, the opposite ends of the joint shaft are provided with the retaining shafts, and the rubber blocks are mounted only on the retaining shafts. Thereby, when the propellant force is generated by the directional caster when the front desk is turned, only the rubber blocks are pressed and restored, and thus the easy turning is provided. Industrial Applicability

[78] In the skateboard of the present invention, the desks are manufactured by plastic injection molding, and the joint shaft is made of hollow metal pipe, and is assembled to the decks.

[79]

Claims

[1] A skateboard characterized in that each of front and rear decks (10 and 20), whi ch are spaced apart from each other by a predetermined distance, are provided thereunder with at least one truck (16), on which a directional caster (50) with a bracket (51) having a predetermined inclination is rotatably mounted; the front and rear decks (10 and 20) are coupled by a joint shaft (30) at a tail of the front deck and at a nose of the rear deck; and in a state in which retaining brackets (31) formed at opposite ends of the joint shaft (30) are surrounded by rubber blocks (40 and 40a), the rubber blocks (40 and 40a) are received in holders (11) formed under the tail of the front deck (10) and the nose of the rear deck (20), are covered by holder caps (1 Ia), and are fixed so as not to be loose.

[2] The skateboard as set forth in claim 1, characterized in that the tail of the front deck and the nose of the rear deck include guide rails (12 and 1 Ib) at front of the holders (11) and the holder caps (1 Ia) such that the retaining brackets (31) of the joint shaft (30) are prevented from escaping and that the joint shaft are placed in the guide rails.

[3] The skateboard as set forth in claim 2, characterized in that the guide rails (12 and l ib) include flanges (13) at inner ends thereof; retaining grooves (34) are defined between the joint shaft (30) and an auxiliary shaft (32) that is shorter than the joint shaft, is fitted around the joint shaft, and is fixed by fixing pins; and the flanges (13) are inserted into the retaining grooves (34).

[4] The skateboard as set forth in claim 1, characterized in that the retaining brackets

(31) formed at the opposite ends of the joint shaft (30) has a "C" shape; and the rubber blocks (40 and 40a) surrounding the retaining brackets (31) include slots (41) having a "C" shape so as to correspond to the C-shaped retaining brackets

(31).

[5] The skateboard as set forth in claim 4, characteristic in that the C-shape slots (41) of the rubber blocks (40 and 40a) include positioning steps (43) such that the middle parts (31a) of the brackets (31) are placed on the positioning steps (43).

[6] The skateboard as set forth in claim 4 or 5, characteristic in that the C-shaped retaining brackets (31) include angled holes (31b) at the middle parts (31a) thereof, so that angled projections (30a) formed on the joint shaft (30) are inserted into the angled holes (31b) and are fixed by welding.

[7] The skateboard as set forth in any one of claims 1, 4 and 5, characteristic in that each of the rubber blocks (40 and 40a) is bisected to completely surround the brackets (31).

[8] The skateboard as set forth in claim 1, characteristic in that the holders (11) of the decks (10 and 20) include spaces (14) having a predetermined height in order to firmly fix the rubber blocks (40 and 40a).

[9] The skateboard as set forth in claim 4 or 5, characteristic in that the rubber blocks (40 and 40a) include damping holes (42) between lateral parts of the C- shaped slots (41) thereof, so as to easily exerts elastic force when twist is generated in a state in which the retaining brackets (31) are inserted into the rubber blocks (40 and 40a).

[10] A skateboard characterized in that each of front and rear decks (100 and 100a), which are spaced apart from each other by a predetermined distance, are provided thereunder with a truck 170, having a predetermined inclination, on which a directional caster (500) with a wheel (510) mounted rotatably on a bracket (520) having a predetermined inclination is rotatably mounted; these separated decks (100 and 100a) are coupled by a joint shaft (300), which is prevented from escaping and can be rotated in a clockwise or counterclockwise direction, between a tail of the front deck and a nose of the rear deck; the joint shaft (300) includes retaining shafts (340), each of which protrudes in opposite directions, at opposite ends thereof, in order to positively regulate the clockwise or counterclockwise rotation thereof and simultaneously facilitate turning of the decks (100 and 100a); the protruding retaining shafts (340) are detachably coupled with rubber blocks (400) having holes (410) into which the retaining shafts (340) are closely inserted; the front and rear decks (100 and 100a) includes joint shaft recesses (110) and rubber block recesses (130) with which the joint shaft (300) comes into close contact when inserted; and caps (200), which are provided with joint shaft recesses (210) and rubber block recesses (220) having the same structures as the joint shaft recesses (110) and the rubber block recesses (130) of the decks (100 and 100a), are covered and fixed by fastening means.

[11] The skateboard as set forth in claim 10, characteristic in that the joint shaft 300 includes grooves (320) and flanges (310) in front of the grooves (320) in order not only to prevent the joint shaft (300) from escaping but also enable the joint shaft (300) to be rotated in the clockwise or counterclockwise direction; and each deck includes a joint shaft recess (110) in which the joint shaft (300) is placed, a pivoting auxiliary flange (140) that is located at an inner end of the joint shaft recess (110), is inserted into the groove (320), and assists the joint shaft to be retained and pivoted, and a retaining groove (120) that is located on one side of the pivoting auxiliary flange (140), so as to be coupled with the grooves and flanges of the joint shaft.

[12] The skateboard as set forth in claim 10 or 11, characteristic in that, in order to rotate the joint shaft inserted into the joint shaft recesses in the clockwise or counterclockwise direction with minimum frictional resistance in a slightly spaced state, an outer end (110a) and lateral edges (HOb) of each joint shaft recess (110) include pivoting auxiliary flanges (140a), wherein the lateral edges (110b) cause the joint shaft (300) to be exposed when the decks (100 and 100a) are separated from each other.

[13] The skateboard as set forth in claim 11 or 12, characteristic in that the retaining shafts (340), each of which protrudes at opposite ends of the joint shaft (300) in opposite directions, are fixed to joint shaft through-holes (330) passing through the joint shaft (300), so as to positively regulate the clockwise or counterclockwise rotation of the joint shaft and simultaneously facilitate turning of the decks (100 and 100a).

[14] The skateboard as set forth in claim 10, characteristic in that the decks (100 and

100a) includes fixing recesses (160); and the caps (200) are provided with inserted shoulders (260) so as to be able to be inserted into the fixing recesses (160), so that the caps (200) are primarily inserted into the decks, and then are fixed by the fastening means.

[15] The skateboard as set forth in claim 10 or 14, characteristic in that the decks (100 and 100a) are provided with support walls (150) having a predetermined height at the parts where the joint shaft recesses (110) and rubber block recesses (130) thereof are formed; and the caps (200) are provided with steps (250), and are engaged with the support walls (150).