[3] However, most conventional insoles are coated with a water-absorbable material such as cloth or leather on the outer surface of a sole body, so that moisture, such as sweat, may penetrate the water-absorbable material. As a result, where such an insole is used for a prolonged period of time, the insole gives out an offensive odor.

Furthermore, since the insole has a water absorbability, a prolonged period of time is required to dry the insole after washing the insole. For this reason, it is difficult to frequently wash the insole. As a result, the insole may not effectively function to maintain the interior of the shoe in a clean state.

[4] In order to solve the above-mentioned problem, an insole made of a non-water absorbable material has been proposed. However, in the case of an insole made of a non-water absorbable hard material, it has no buffering function, and causes the foot to be sweaty. Furthermore, a separate cutting process is required to manufacture such an insole. For this reason, such an insole cannot be applied to various kinds of shoes, which are manufactured by different manufacturers or have different designs. On the other hand, in the case of an insole made of a non-water absorbable soft material, there is a problem in that the insole may be folded in the interior of the shoe by the foot or may be drawn out of the shoe by the foot when the user takes off the shoe. Thus, there is an inconvenience in using the insole. In order to solve this problem, a new structure to firmly hold an insole in a shoe has been proposed, in which a fastening means is fixed to the lower surface of the insole, and an attachment means is fixed to the bottom surface of the shoe to attach the insole to the bottom surface of the shoe inside the shoe. In this case, however, the fastening means and attachment means are hard on the foot of the user. Of course, such a problem may be solved by arranging the fastening means at a position inclined from the central axis of the insole toward one side of the insole (corresponding to the arch portion of the sole of the foot). However, this method involves a problem in that the fastening means may easily be separated from the attachment means due to a rotational moment generated when the user wears or takes off the shoe.

[5] The conventional insoles also have a problem in that it is impossible to easily remove foreign matter (dust or mold) accumulated on a portion of the insole cor- responding to the toe of the foot, so that the function of the insole to maintain the interior of the shoe in a clean state is degraded.

[6] Meanwhile, insoles, which have an osteopathy function without taking into con- sideration the intrinsic insole function, have been proposed. However, such insoles may be unmarketable because they may be hard on the users and may cause the users discomfort in severe cases, except for users who strongly requre the osteopathy function.

[7] Disclosure of Invention Technical Problem [8] Therefore, the present invention has been made in view of the above-mentioned problems incurred in the related art, and it is an object of the invention to provide a sanitary insole for a shoe which not only has a foreign matter escape-preventing structure at a front end of the insole, but also has an air circulation structure and a buffering structure at an upper surface of the insole, thereby being capable of ef- fectively maintaining the shoe in a clean state and providing a superior wearing effect to the user.

[9] Technical Solution [10] In accordance with the present invention, this object is accomplished by providing A sanitary insole for a shoe comprising: an insole body; and a foreign matter escape- preventing barrier protruded from a front end of the insole body to extend upwardly from an upper surface of the insole body, the barrier preventing foreign matter existing on the upper surface of the insole body from escaping from the insole, and thus, being accumulated in the interior of the shoe, whereby a user can remove the foreign matter accumulated near the barrier after taking off the insole, thereby causing the insole to be maintained in a clean state.

[11] The insole body may be made of a non-water absorbable soft rubber exhibiting a superior flexibility. The insole may further comprise: a plurality of uniformly-spaced linear protrusions formed at the upper surface of the insole body, the circular protrusions being arranged at front and rear portions of the insole body; and a plurality of uniformly-spaced circular protrusions formed at the upper surface of the insole body, the linear protrusions being arranged at a central portion of the insole body and a rear edge portion of the insole body, each circular protrusion having a hollow-stepped structure and including a contact portion, a support portion, a through hole centrally formed through the contact portion, and a space defined in the circular protrusion to communicate with the through hole, whereby the insole has an air circulation function and a buffering function.

[12] The insole may further comprise a fitting hole formed through the central portion of the insole body at a predetermined position so that the fitting hole is fitted around a fitting protrusion fixed to an interior bottom surface of the shoe at a position cor- responding to the position of the fitting hole, the fitting hole having a size cor- responding to a size of the fitting protrusion, whereby the insole is detachably attached to the interior bottom surface of the shoe.

Brief Description of the Drawings [13] The above and other objects and features of the present invention will become more apparent from the following description of preferred embodiments given in conjunction with the drawings, in which: [14] FIG. 1 is a perspective view illustrating a sanitary insole according to the present invention; [15] FIG. 2 is a perspective view illustrating a fitting protrusion according to the present invention; [16] FIGS. 3A and 3B illustrate a circular protrusion according to the present invention, wherein FIG. 3A is a sectional view of the circular protrusion, and FIG. 3B is a schematic sectional view illustrating an operation of the circular protrusion; and [17] FIG. 4 is an enlarged sectional view illustrating a part of linear protrusions according to the present invention.

[18] Best Mode for Carrying Out the Invention [19] Referring to FIG. 1, an insole for a shoe according to an exemplary embodiment of the present invention is illustrated. As shown in FIG. 1, the insole includes an insole body made of a non-water absorbable soft rubber material exhibiting a superior flexibility. A foreign matter escape-preventing barrier 1 is protruded from a front end of the insole body to extend upwardly from an upper surface of the insole body. A plurality of uniformly-spaced linear protrusions 3 and a plurality of uniformly-spaced circular protrusions 4 are formed at the upper surface of the insole body. The circular protrusions 4 are arranged at front and rear portions of the insole body. The linear protrusions 3 are arranged at a central portion of the insole body and a rear edge portion of the insole body (surrounding the rear portion of the insole body where the circular protrusions 4 are arranged). Referring to FIG. 3A, each circular protrusion 4 includes a contact portion 401 and a support portion 402, which form a hollow-stepped structure. The support portion 402 is relatively thick. A through hole 403 is centrally formed through the contact portion 401. A space 404 is defined in each circular protrusion 4 to communicate with the associated through hole 403.

[20] A fitting hole 2 having a predetermined size is centrally formed through the central portion of the insole body so that the fitting hole 2 is fitted around a fitting protrusion 5 fixed to a bottom surface of the shoe inside the shoe at a desired position.

[21] Snce the insole having the above-described structure according to the present invention is made of a non-water absorbable soft material having a superior flexibility, the insole is superior in terms of washability and dryability, and is very soft. Also, the barrier 1 formed at the front end of the insole body prevents foreign matter existing on the upper surface of the insole body from escaping from the insole, and thus, being ac- cumulated in the interior of the shoe (in particular, a portion of the shoe corresponding to the toe portion of the foot where the fingers of the user or a washing tool may hardly reach during a shoe washing process). The linear protrusions 3 and circular protrusions 4 formed on the upper surface of the insole body minimize the area of the insole contacting the sole of the foot to provide an air circulation function. In particular, since each circular protrusion 4 has a hollow-stepped structure including its contact portion 401 and its support portion 402, the contact portion 401 provides a cushion effect (buffering effect) by virtue of the support portion 402 when the contact portion 401 is pressed by the sole of the foot, as shown in FIG. 3B. At this time, the contact portion 401 is retracted into the space 404 as the support portion 402 is bent, as shown in FIG.

3B. By virtue of the bending of the support portion 402, a resilience to urge the contact portion 401 to return to its original state is generated. Even when the contact portion 401 is pressed to be retracted into the space 404, the through hole 403 of the circular protrusion 4 maintains a desired air circulation between the insole and the sole of the foot.

[22] As described above, the circular protrusions 4 are arranged at the front and rear portions of the insole body respectively corresponding to the toe and heel portions of the foot, to which the weight of the user is concentratedly applied while walking. Ac- cordingly, the insole of the present invention can exhibit a superior buffering effect even when the insole has a reduced thickness. Also, the linear protrusions 3 are arranged in a uniformly spaced state at the remaining upper surface portion of the insole, except for the upper insole surface portion where the circular protrusions 4 are arranged. Accordingly, it is possible to obtain a maximal air circulation effect.

[23] Once the fitting hole centrally formed through the insole body is fitted around the fitting protrusion 5 fixed to the bottom surface of the shoe inside the shoe, the insole cannot be movable in the interior of the shoe while the user walks. Thus, it is possible to prevent the insole from being folded or drawn out of the shoe when the user takes off the shoe. In addition, it is possible to easily and rapidly achieve the insole attaching/detaching process.

Industrial Applicability [24] As apparent from the above description, the present invention provides an insole having the following features: [25] First, the insole is superior in terms of washability and dryability, so that it can be frequently washed. The insole can be reused, immediately after the washing thereof.

Thus, it is possible to maintain the insole in a clean state, so that the user can wear the shoe in a pleasant state.

[26] Second, the insole can be prepared to have various sizes, and can be precisely fitted in the shoe with reference to the heel portion of the shoe. Accordingly, the insole can be applied to shoes, which are manufactured by different manufacturers or have different designs, without an additional cutting process. Thus, the insole can be widely and generally used.

[27] Third, the barrier 1 formed at the front end of the insole can prevent foreign matter existing on the upper surface of the insole body from escaping from the insole, and thus, being accumulated in the interior of the shoe (in particular, a portion of the shoe corresponding to the toe portion of the foot where the fingers of the user or a washing tool may hardly reach during a shoe washing process). It is also possible to prevent foreign matter such as dust or mold exhibiting a bad effect for sanitation from being accumulated and inhabiting in the interior of the shoe. Such foreign matter can easily be removed only by the washing of the insole. Accordingly, it is possible to maintain the interior of the shoe in a clean state.

[28] Fourth, the linear protrusions 3 and circular protrusions 4 formed on the upper surface of the insole are effectively arranged to minimize the effective area of the insole contacting the sole of the foot, and thus, to provide an effective air circulation effect capable of maximi2ing the area of the sole of the foot contacting the air. Ac- cordingly, it is possible to prevent the foot from being sweaty.

[29] Fifth, the circular protrusions 4 exhibit a cushion effect when the contact portions 401 are pressed. In accordance with this cushion effect, the circular protrusions 4 absorb impact applied to the sole of the foot when the user walks. Accordingly, the insole provides a comfortable wearing effect to the user. When each circular protrusion 4 is pressed, the contact portion 401 thereof is mainly retracted into the space 404 defined in the circular protrusion 4. Accordingly, there is no phenomenon that the insole may be hard on the user and may cause the user discomfort in severe cases, as in conventional osteopathy insoles.

[30] Sixth, it is possible to effectively prevent the insole from being folded or drawn out of the shoe when the user takes off the shoe, by the fitting hole 2 centrally formed through the insole body and the fitting protrusion 5 fixed to the interior bottom surface of the shoe at a desired position (corresponding to the position of the fitting hole 2).

Accordingly, the insole can be reliably used. Although the fitting hole 2 is formed through the insole body, the fitting protrusion 5 fills the fitting hole 2 in the state in which the fitting protrusion 5 is fitted in the fitting hole 2, so that the insole is maintained in a flat state. Accordingly, it is possible to solve the problems incurred in conventional cases in fixing an insole to the bottom surface of a shoe, that is, a phenomenon that fixing protrusions (attachment means) fixed to the bottom surface of the shoe may be hard on the foot, and instable fixing of the insole.

[31] Thus, the present invention provides a multi-functional insole, which can be used in a more sanitary state, provides a superior wearing effect, and is convenient and reliable in use.

[32] Although the preferred embodiments of the invention have been disclosed for il- lustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.