Technical Field The present invention relates to a wheel for use in a travelling means such as an in-line skate, a roller skate, a skateboard or a kick board, and a carrying means such as a travel bag. In particular, the invention relates to an in¬ line skate wheel with a detachable tire, which is useful in case where a great force is exerted to the axial direction of the wheel, i.e., to the direction perpendicular to the travelling direction thereof.

Background Art In general, in-line skates or skateboards have been widely used for leisure sports, but not only for a simple travelling means. Thus, the users enjoy various stunt actions such as rotations, jump, or sliding, along with a simple rolling motion. Accordingly, the wheel of these travelling means has been especially designed so as to secure durability and safety. The wheel of the in-line skate, which is representative of these travelling means, is composed of a central hub formed of a plastic material and a tire, in order to endure a user's vigorous actions and motions. In order to improve the bonding force between the central hub and the tire, the wheel is formed in such a way that the central hub is inserted into the tire mould and then the tire is molded, integrally with the central hub. In this way, the wheel exhibit a good bonding force between the tire and the central hub to thereby prevent the tire from being released from the tire, but still embraces disadvantages as follows. First, frequently the wheel is fabricated at the state that the center of the central hub is not aligned with that of the tire. In this case, when the wheel rotates, the wobbling phenomenon occurs in the wheel, thereby leading to unnecessary energy loss. In addition, the central hub is formed of a plastic material and thus when in a high speed travelling or rotation, the central hub cannot effectively absorb the heat generated from a bearing, thereby imposing damages on the bearing. Due to a user's vigorous actions, the bearing may be displaced from the bearing seat. As a result, the degradation of the bearing is accelerated and unnecessary noise is produced, which may cause uncomfortable feeling to the users. Furthermore, if the tire is worn off, the wheel needs to be replaced. The conventional wheel is designed such that the tire cannot be assembled to and disassembled from the central hub, disadvantageously thereby involving disposal of the entire wheel. In order to overcome the disadvantages of the conventional wheel composed of a plastic central hub and a tire, a wheel consisting of a metallic central hub and a tire has been proposed. This wheel having a metallic hub has solved many problems associated with the conventional plastic hub wheel, but still embraces a disadvantage in that the tire cannot be separated from the central hub formed of a metallic material. Thus, considering that the metallic hub wheel is more expensive relatively to the conventional wheels, in the case where the wheel is replaced due to the wearing-off of the tire, a significant financial burden is imposed on the users.

Disclosure Technical Solution Accordingly, the present invention has been made in order to solve the above problems occurring in the art, and it is an object of the invention to provide an in-line skate wheel with a detachable wheel, in which the central hub and the tire can be assembled/disassembled to/from each other, and the tire can be prevented from being released from the central hub. Another object of the invention is to provide an in¬ line skate wheel with a detachable tire, in which the central hub is formed of a metallic material to thereby absorb heat generated by a bearing and thus alleviate the damage of bearing, and also to effectively distribute the central hub' s weight far from the axis thereof and thus obtain a high rotational moment of inertia. A further object of the invention is to provide an in¬ line skate wheel with a detachable tire, in which the bearing can be prevented from being displaced from the bearing seat, thereby retaining the precision and rigidity thereof during an extended time of service.

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. l(a) is a partially cut-out perspective view of a conventional in-line skate wheel having a hub formed of a plastic material; FIG. l(b) is a perspective view of a conventional in- line stake wheel having a hub formed of a metallic material; FIG. 2 (a) is a perspective view of an in-line stake wheel according to the invention; FIG. 2 (b) is a front view of the in-line skate wheel of the invention; FIG. 3 is an exploded perspective view of the in-line skate wheel of the invention; FIG. 4 (a) is a perspective view of the central hub of the in-line stake wheel of the invention; FIG. 4 (b) is a front view of the central hub of the in¬ line skate wheel of the invention; FIG. 5 is a perspective view of the tire of the in-line stake wheel of the invention; FIG. 6 is a perspective view and partially enlarged view of the tire-fixing rim in the in-line state wheel of the invention; FIG. 7 is a perspective view of the in-line stake wheel of the invention, showing an assembling method of the tire- fixing rim; FIG. 8 is a perspective view of the tire-fixing rim, showing the inner face thereof; and FIG. 9 is a partially cut-out perspective view and enlarged perspective view of the in-line skate wheel of the invention.

Mode for Invention The preferred embodiments of the present invention will be hereafter described in detail with reference to the accompanying drawings. FIG. 1 (a) is a partially cut-out perspective view of a conventional in-line skate wheel having a hub formed of a plastic material, and FIG. 1 (b) is a perspective view of a conventional in-line stake wheel having a hub formed of a metallic material. As shown in FIG. 1 (a) , the conventional in-line skate wheel is composed of a central hub 10 and a tire 20. In the manufacturing of the conventional wheel, the wheel is molded with the central hub 10 inserted into a tire forming mould, and thus a user cannot detach the tire 20 from the central hub 10. In the in-line skate wheel of FIG. 1 (b) , the central hub 10 is formed of a metallic material. The wheel of FIG. l(b) is somewhat improved from one in FIG. l(a), but still embraces a problem that the tire 20 cannot be disassembled from the central hub 10. In order to solve the problem, the tire 20 is designed so as to have a good wear resistance. In this case, however, a sense of comfortable riding and cushioning force are degraded disadvantageously. FIG. 2 (a) is a perspective view of an in-line stake wheel according to the invention, and FIG. 2 (b) is a front view of the in-line skate wheel of the invention. As illustrated in FIGS. 2 (a) and 2 (b) , the in-line skate wheel of the invention is composed of a central hub 10, a tire 20 and a tire-fixing rim 30. The tire-fixing rim 30 is formed in such a manner to cut part of the central hub 10 such that the tire 20 can be assembled into and disassembled from the central hub 10. After the tire 20 is inserted into the central hub 10, the tire-fixing rim 30 is fixed to the central hub 10, thereby preventing the tire 20 from being released from the central hub 10. The connection of the tire-fixing rim 30 with the central hub 10 will be described hereinafter. FIG. 3 is an exploded perspective view of the in-line skate wheel of the invention. As shown in FIG. 3, the in-line stake wheel of the invention is structured such that the tire 20 can be detached from the central hub 10, and, after assembled, the tire 20 cannot be released from the central hub 10 by means of the tire-fixing rim 30. The central hub 10 and the tire- fixing rim 30 are connected with each other through thread engagement, i.e., a male thread is formed in the central hub 10 and a female thread is formed in the tire-fixing rim 30. In order for the tire 20 not to be released from the central hub 10 even in a user's vigorous motion, and in order for the tire not to be slipped relative to the central hub 10, an additional means is to be provided, along with the tire-fixing rim 30. Details on this purpose will be described hereinafter. FIG. 4 (a) is a perspective view of the central hub of the in-line stake wheel of the invention, and FIG. 4 (b) is a front view of the central hub of the in-line skate wheel of the invention. The central hub 10 is composed of an inner bearing seat 15 where a bearing can be seated, an outer rim 11 where the tire 20 is rested, and a radial connection support 16 for connecting the inner bearing seat 15 and the outer rim 11 with each other. Along one outer peripheral edge of the outer rim 11 is formed a tire guard 12 protruded in a radial direction such that the tire 20 is not released therefrom. The tire guard 12 is not simply formed of a simple "^=" shaped protrusion, but is provided with a connection projection 17 protruded in the direction that the tire 20 is contacted. The connection projection 17 will be explained hereinafter. In the outer circumferential surface of the outer rim 11 is formed a plurality of slide-inhibiting projections 13 having the form of a cylinder of semi-circle cross-section. The slide-inhibiting projections are engaged with a plurality of slide-inhibiting grooves 22, which are formed in the inner circumferential surface of an inserting hole of the tire 20, thereby preventing the tire 20 from being slid in the rotational direction of the central hub 10 relatively thereto. Along the other peripheral edge of the outer rim, i.e., at the opposite side of the tire guard 12, is not provided with a guard such that the tire 20 can be inserted and released. However, a male thread 14 is formed therein so as to fasten the tire-fixing rim 30. FIG. 5 is a perspective view of the tire of the in-line stake wheel of the invention. As shown in FIG. 5, in the inner face of the tire 20 is formed an inserting protrusion 21 protruded towards the center thereof so as to be wrapped around by the tire guard 12 of the central hub 10 and a tire-fixing rim 30. In addition, in the inner side of the inserting protrusion 21 is formed a plurality of slide-inhibiting grooves 22 having the form of a cylinder having a semi-circle cross-section, which is to be engaged with the slide-inhibiting projections 13 formed in the central hub 10. To the left and right side along the axial direction of the inserting protrusion 21, a connection groove 23 is formed. The connection groove 23 is engaged with the connection protrusion 17 and 31, which are formed respectively in the tire guard 12 of the central hub 10 and the tire-fixing rim 30. Details thereon will be described hereinafter. FIG. 6 is a perspective view and partially enlarged view of the tire-fixing rim in the in-line state wheel of the invention, and FIG. 7 is a perspective view of the in- line stake wheel of the invention, showing an assembling method of the tire-fixing rim using a special tool. As illustrated in FIGS. 6 and 7, the tire-fixing rim 30 has the form of a rim, and in the inner face thereof is formed a female thread 32. The female thread 32 is engaged with the male thread 14 formed in the central hub 10 to thereby function to combine the tire-fixing rim 30 with the central hub 10. When the tire 20 is inserted into the central hub 10 and then the tire-fixing rim 30 is combined with the central hub 10, the fire-fixing rim 30 is to be fitted into the male thread 14. At this time, the tire-fixing rim 30 is configured such that it is to be inserted into a gap formed by and between the tire 20 and the central hub 10, thereby being unable to rotate and fit the tire-fixing rim 30 using hands. Thus, a specially designed assembling tool 40 is provided in order to rotate and fit the tire-fixing rim 30. Here, the tire-fixing rim 30 is provided with plural auxiliary grooves 33 formed in the lateral face thereof so as to be engaged with the assembling tool 40. That is, a specific portion of the assembling tool 40 is engaged with the plural auxiliary grooves 33 formed in the tire-fixing rim 30, which then can be rotated to thereby be assembled to and disassembled from the central hub 10. The assembling tool 40 of this purpose is not included in the scope of the invention, and simply a screwdriver or the like can be used to connect or disconnect the tire-fixing rim 30 to the central hub 10, using the auxiliary grooves 33. Details thereon will not be described here. FIG. 8 is a perspective view of the tire-fixing rim, showing the inner face thereof. As illustrated in FIG. 8, the inner lateral face of the tire-fixing rim 30 is provided with a connection protrusion 31 having a 1S' shape, not a flat shape. The connection protrusion 31 is engaged with the connection groove 23 formed in the tire 20, thereby holding the tire 20 to the central hub 10 so as not to be released therefrom. FIG. 9 is a partially cut-out perspective view and enlarged perspective view of the in-line skate wheel of the invention. As illustrated in FIG. 9, in one outer peripheral edge of the outer rim 11 of the central hub 10 is formed a tire guard 12 protruded in the radial direction in order for the tire 20 not to be released from the central hub 10. The tire guard 12 functions to hold the tire 20 to the central hub 10 so as not to be escaped therefrom when it is combined thereto by means of the tire-fixing rim 30. However, usually, users enjoy vigorous actions or motions with an in¬ line skate or a kick board, and thus the tire guard 12 alone is not sufficient to prevent partial escape of the tire 20. Therefore, the tire guard 12 is provided with a connection protrusion 17 projected towards the contact with tire 20. The connection protrusion 17 is inserted into and engaged with the connection groove 23 formed in the tire 20, to thereby prevent even partial escape of the tire 20. Similarly, the tire-fixing rim 30 is provided with a connection protrusion 31 formed towards the contact with the tire 20, and the connection protrusion 31 is engaged with the connection groove 23 formed in the tire 20. The connection protrusions 17 and 30 formed in the central hub 10 and the tire-fixing rim 30 respectively has a rounded form, not a rectangular form. This form matches that of the connection groove 23 formed in the inserting protrusion 21 of the tire 20 and thus the connection groove 23 of the tire 20 is prevented from being partially split or tore off, due to a user's vigorous action.

Industrial Applicability As described above, in the in-line skate wheel having a detachable tire according to the invention, the tire and the central hub are separately fabricated and then assembled to each other, thereby significantly reducing the wobbling phenomenon of the wheel. When travelling with a high speed, the metallic central hub can absorb the heat generated from the bearing, thereby alleviating the degradation of the bearing. The central hub is formed of a metallic material, which has a rigidity higher than a plastic material, thereby enabling to distribute the weight thereof towards the tire and thus obtain a higher moment of inertia. In addition, the tire is prevented from being slid against the central hub and also from being escaped partially or in its entirety from the central hub, even due to a user's vigorous actions or motions. The tire can be assembled to and disassembled from the central hub, thereby enabling to replace the tire only and thus providing a financial benefit to the user. Various tires having a variety of sizes and formed of a variety of materials can be used by replacing, thereby providing a wide range of pleasures and joys to the user. 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.