Upper Structure for a Sports Shoe

BACKGROUND OF THE INVENTION

The present invention relates generally to an upper structure for a sports shoe, and more particularly, to improvement in structure that can not only enhance holdability or holding property as an upper but also improve wearer's touch on a foot.

An upper structure for a sports shoe was shown in publications such as Japanese patent application publication Nos. 2004-105323 (hereinafter referred to JP'323) and 2006-511306 (hereinafter referred to JP '306).

JP '323 describes that a first region of an upper is formed of a first knitted fabric in which a first synthetic resin fiber having a low softening point is knitted, a second region of an upper is formed of a second knitted fabric in which a second synthetic resin fiber having a higher softening point than the softening point of the first synthetic resin is knitted, and the first knitted fabric is hardened by heating the upper at a temperature that is higher than the softening point of the first synthetic resin but lower than the softening point of the second synthetic resin (see paras. [0039], [0041], [0047], and FIGS. 1 to 6).

JP '306 describes that an instep is formed of of a textile including a fusible strand and a specified region of the instep is formed with a fusion area of the fusible strand by heating the specified region of the instep (see paras. [0014], [0015], [0020], and FIGS. 1, 3A to 3D and 5).

In the upper structure shown in JP '323, although holdability of the upper is improved by hardening the first knitted fabric, in the first region of the upper the hardened first knitted fabric is distributed not only on an outer surface but also on an inner surface of the upper. As a result of this, when wearing a shoe the hardened first knitted fabric contacts a wearer's foot and thereby wearer's touch on the foot might be deteriorated.

In the upper structure shown in JP '306, although it recites that stability and supportability of the instep is improved by forming the fusion area of the fusible strand at the specified region of the instep, in the specified region the fusion area is distributed not only on an outer surface but also on an inner surface of the instep. As a result of this, when wearing a shoe the fusion area contacts a wearer's foot and thereby wearer's touch on the foot is deteriorated.

The present invention has been made in view of these circumstances and its object is to provide an upper structure for a sports shoe that can not only enhance holdability as an upper but also improve wearer's touch on the foot.

Other objects and advantages of the present invention will be obvious and appear hereinafter.

SUMMARY OF THE INVENTION

An upper structure for a sports shoe according to the present invention includes an upper for covering a foot of a shoe wearer. The upper is formed of a knitted fabric that includes thermally fusible yarn. The thermally fusible yarn is disposed on an outer surface side of the upper. The thermally fusible yarn is fusion-bonded and cured in the knitted fabric by carrying out heat treatment of the knitted fabric including thermally fusible yarn and the knitted fabric including thermally fusible yarn is made harder on the outer surface side of the upper than on an inner surface side of the upper by the heat treatment.

According to the present invention, the thermally fusible yarn is fusion-bonded and cured in the knitted fabric by the heat treatment and the knitted fabric is thus hardened, thereby improving holdability of the upper. Moreover, since the thermally fusible yarn is disposed on the outer surface side of the upper, the knitted fabric after the heat treatment is made harder on the outer surface side of the upper than on the inner surface side of the upper. As a result, wearer's touch on the foot can be improved with the holdability of the upper maintained. Furthermore, by hardening the knitted fabric including thermally fusible yarn, solidity (i.e. three-dimensional shape retainability) of the upper formed of the knitted fabric can be improved. Also, by hardening the outer surface side of the upper including thermally fusible yarn, the surface of the upper can be reinforced.

The knitted fabric including thermally fusible yarn may comprise a front yarn and a back yarn that are arranged in a parallel relationship, and the front yarn and the back yarn may be disposed on the inner surface side of the upper.

The knitted fabric including thermally fusible yarn may be disposed at a region of less elasticity that includes either one of a heel outer periphery portion, a midfoot outer periphery port ion, or a forefoot outer periphery portion of the upper.

A manufacturing method of an upper structure for a sports shoe having an upper for covering a foot of a shoe wearer according to the present invention comprises the following steps:

i) forming the upper of a knitted fabric including thermally fusible yarn in such a way that the thermally fusible yarn is disposed on an outer surface side of the knitted fabric of the upper; and

ii) carrying out heat treatment of the knitted fabric at a temperature equal to or higher than melting point of the thermally fusible yarn so that the thermally fusible yarn is fusion-bonded and cured in the knitted fabric, whereby the knitted fabric including thermally fusible yarn is made harder on the outer surface side of the upper than on an inner surface side of the upper by the heat treatment.

According to the present invention, by the heat treatment of the knitted fabric including the thermally fusible yarn, the thermally fusible yarn is fusion-bonded and cured in the knitted fabric and thus hardens the knitted fabric, thereby improving holdability of the upper. Moreover, since the thermally fusible yarn is disposed on the outer surface side of the upper, the knitted fabric after the heat treatment is made harder on the outer surface side of the upper than on the inner surface side of the upper. As a result, wearer's touch on the foot can be improved with holdability of the upper maintained. Furthermore, by hardening the knitted fabric including the thermally fusible yarn, solidity (i.e. three-dimensional shape retainability) of the upper formed of the knitted fabric can be improved. Thereby, workability at the time of assembly of a sports shoe using such an upper can be improved. Also, by hardening the outer surface side of the upper including thermally fusible yarn, the surface of the upper can be reinforced.

The heat treatment may be conducted by heat press of a side surface of the upper.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the invention, reference should be made to the embodiments illustrated in greater detail in the accompanying drawings and described below by way of examples of the invention. In the drawings, which are not to scale:

FIG. 1 is a top plan schematic view of an upper structure for a sports shoe according to an embodiment of the present invention;

FIG. 2 is a medial side schematic view of the upper structure of FIG. 1;

FIG. 3 is a lateral side schematic view of the upper structure of FIG. 1;

FIG. 4 is a bottom schematic view of the upper structure of FIG. 1;

FIG. 5 is a top plan schematic view of a sports shoe employing the upper structure of FIG. 1;

FIG. 6 is a medial side schematic view of the sports shoe of FIG. 5;

FIG. 7 is a lateral side schematic view of the sports shoe of FIG. 5;

FIG. 8 is a rear side schematic view of the sports shoe of FIG. 5;

FIG. 9 illustrates a knitting pattern of pile knitting that is used as a knitted fabric forming the upper structure of FIG. 1;

FIG. 9A is an enlarged view of a portion of the knitting pattern of the pile knitting of FIG. 9;

FIG. 10 is a cross sectional view of FIGS. 9A, 11A and 12A taken along line X-X, illustrating a most preferred arrangement of respective yarns forming the respective knitted fabric;

FIG. 11 illustrates a knitting pattern of back-thread tuck stitching that is used as a knitted fabric forming the upper structure of FIG. 1;

FIG. 11A is an enlarged view of a portion of the knitting pattern of the back-thread tuck stitching of FIG. 11;

FIG. 12 illustrates a knitting pattern of float knitting that is used as a knitted fabric forming the upper structure of FIG. 1;

FIG. 12A is an enlarged view of a portion of the knitting pattern of the float knitting of FIG. 12;

FIG. 13 illustrates positional relation of respective yarns at the time of yarn feeding when knitting a knitted fabric forming the upper structure of FIG. 1;

FIG. 14 illustrates a heating process of the upper structure of FIG. 1;

FIG. 15 illustrates a heating process of the upper structure of FIG. 1;

FIG. 16 is a top plan view of a foot, showing expansion/contraction data of skin of the foot at the time of running;

FIG. 17 is a medial side view of the foot, showing expansion/contraction data of the skin of the foot at the time of running; and

FIG. 18 is a lateral side view of the foot, showing expansion/contraction data of the skin of the foot at the time of running.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, FIGS. 1 to 4 show an upper structure for a sports shoe according to an embodiment of the present invention. These drawings illustrate an upper alone. In an exemplification, the upper structure is applied to a walking shoe or a running shoe. Of course, it also has an application to shoes of different kinds.

As shown in FIGS. 1 to 4, an upper 1 that covers a foot of a shoe wearer is formed of a knitted fabric, which is knitted into a sock-shape. The upper 1 has an opening 1a for entry of the foot into the upper 1. The knitted fabric of the upper 1 comprises a knitted fabric region 1A to 1D (see vertical lines) having thermally fusible yarn that is fusion-bonded, cured and impregnated into the region 1A to 1D, and a knitted fabric region 1E (see white void areas defined by outlines) having no thermally fusible yarn. The thermally fusible yarn is yarn of relatively lower melting point (e.g. low-melting-point nylon) and it includes “ELDER®” of TORAY Industries, Inc. but is not limited thereto. Any other suitable yarn having lower melting point and thermo adhesiveness can be used.

The knitted fabric region 1A is disposed at a heel outer perimeter portion, the knitted fabric region 1B at a midfoot-medial-side outer perimeter portion, the knitted fabric region 1C at a midfoot-lateral-side outer perimeter portion, and the knitted fabric region 1D at a forefoot outer perimeter portion. The knitted fabric region 1A to 1D is formed integrally with each other at an area extending from a heel portion through a midfoot portion to a forefoot portion of the upper 1.

A position of each of the knitted fabric region 1A to 1D corresponds to a low elastic region of the upper 1. We will explain that using FIGS. 16 to 18. These drawings illustrate elongation and contraction data of skin of a foot during running. In the drawings, a dark gray region indicates a larger elongation of skin, a light gray region indicates a larger contraction of skin, and a white void region indicates a smaller elongation and contraction of skin. As can be seen from FIGS. 16 to 18, a region of smaller elongation and contraction of skin of the foot during running is a heel outer perimeter portion, a midfoot outer perimeter portion, and a forefoot outer perimeter portion in the ascending order. That is why we selected the heel outer perimeter portion, the midfoot outer perimeter portion, and the forefoot outer perimeter portion as the low elastic region of the upper 1 for locating the knitted fabric region 1A to 1D.

Then, we will explain a knitting pattern of pile knitting as an example of the knitted fabric region 1A to 1D using FIGS. 9, 9A and 10. In FIGS. 9 and 9A, out of the page indicates outside of the upper and into the page inside of the upper. As shown in FIGS. 9 and 9A, the knitting pattern of the pile knitting is formed of a multiple of needle loops n and sinker loops s that are knitted by a front yarn a and a back yarn b arranged in a parallel relationship and a thermally fusible yarn c combined therewith. In FIG. 9, each stitch p constitutes pile. In FIGS. 9 and 9A, for illustration purpose, the front yarn a is shown with a double line, the back yarn b with a thin single line, and the thermally fusible yarn c with a thick single line. Also, as shown in FIG. 10, the front yarn a and the back yarn b are disposed on the upper inside surface and the thermally fusible yarn c is disposed on the upper outside surface.

In addition, those drawings illustrate a typical knitting pattern of the pile knitting in which the thermally fusible yarn c is clearly disposed on the upper outside surface at the entire stitches p. However, in an actual product, at a part of the stitches p, the thermally fusible yarn c may possibly be disposed at a position close to the upper inside surface according to slight variation of thickness or tension of yarn. The same can be said about other knitting patterns described later.

The front yarn a and the back yarn b have a melting point higher than a melting point of the thermally fusible yarn c. For example, as the front yarn a, two combined yarns are used, each yarn formed of two twisted polyester yarns each of which has a melting point of 250-260° C. and a thickness of 100 denier (i.e. 100 d). As the back yarn b, a yarn formed of two twisted polyester yarns, each of which has a melting point of 250-260° C. and a thickness of 100 denier (i.e. 100 d), is used. As the thermally fusible yarn c, two or four combined nylon yarns are used, each yarn having a melting point of 215-220° C. and a thickness of 110 denier (i.e. 110 d). In the case of the above-mentioned “ELDER®” of TORAY Industries, Inc., the melting point is 110-120° C. Such combination of the front yarn a, the back yarn b and the thermally fusible yarn c is applicable to the other knitting patterns described below.

Next, a knitting pattern of back-thread tuck stitching will be explained as another example of the knitted fabric region 1A to 1D using FIGS. 11 and 11A. In these drawings, out of the page indicates outside of the upper and into the page inside of the upper, as with the case of the pile knitting.

As shown in FIGS. 11 and 11A, the knitting pattern of the back-thread tuck stitching is formed of a multiple of needle loops n and sinker loops s that are knitted by a front yarn a and a back yarn b arranged in a parallel relationship and a thermally fusible yarn c combined therewith. In FIGS. 11 and 11A, for illustration purpose, the front yarn a is shown with a double line, the back yarn b with a thin single line, and the thermally fusible yarn c with a thick single line. In this knitting pattern of the back-thread tuck stitching as well, the front yarn a and the back yarn b are disposed on the upper inside surface and the thermally fusible yarn c is disposed on the upper outside surface (see FIG. 10). The front yarn a and the back yarn b have a melting point higher than a melting point of the thermally fusible yarn c.

Then, a knitting pattern of float knitting will be explained as a further example of the knitted fabric region 1A to 1D using FIGS. 12 and 12A. In these drawings, out of the page indicates outside of the upper and into the page inside of the upper, similar to the cases of the pile knitting and the back-thread tuck stitching.

As shown in FIGS. 12 and 12A, the knitting pattern of the float knitting is formed of a multiple of needle loops n and sinker loops s that are knitted by a front yarn a and a back yarn b arranged in a parallel relationship and a thermally fusible yarn c combined therewith. In FIGS. 12 and 12A, for illustration purpose, the front yarn a is shown with a double line, the back yarn b with a thin single line, and the thermally fusible yarn c with a thick single line. In this knitting pattern of the float knitting as well, the front yarn a and the back yarn b are disposed on the upper inside surface and the thermally fusible yarn c is disposed on the upper outside surface (see FIG. 10). The front yarn a and the back yarn b have a melting point higher than a melting point of the thermally fusible yarn c.

In each of the knitting patterns of the above-mentioned pile knitting, back-thread tuck stitching, and float knitting, in order to achieve a knitting pattern in which the thermally fusible yarn c disposed on the upper outside surface, there is need to feed the front yarn a, the back yarn b and the thermally fusible yarn c in a parallel relationship as shown in FIG. 13, in which the fusible yarn c is disposed on an innermost side at a hook portion 51 of a latch needle 50, the back yarn b is disposed on an outermost side at the hook portion 51 of the latch needle 50, and the front yarn a is disposed between the fusible yarn c and the back yarn b. In order to feed the front yarn a, the back yarn b and the thermally fusible yarn c in a parallel relationship, positional relation between the latch needle 50 and a yarn guide and tension of yarns should be controlled. Specifically, positional relation of the three yarns a, b and c can be controlled in such a manner that a yarn guide which can feed a yarn faster than any other yarn guide feeds the thermally fusible yarn c and tension of the yarn is maintained at the highest.

Also, in a boundary portion between the knitted fabric region 1A to 1D and the knitted fabric region 1E on the upper inside surface, pile texture is provided (not shown). The pile texture functions as a buffer area in the event that the thermally fusible yarn c is fused to soak into the upper inside surface through the boundary portion of the knitted fabric and hardens the upper inside surface at heat treatment mentioned later. By providing the pile texture in the boundary portion, a foot of a shoe wearer is prevented from directly touching such a hardened area on the upper inside surface and thereby wearer's touch on the foot can be improved.

A manufacturing method of the above-mentioned upper 1 will be explained hereinafter.

When knitting the upper 1, the knitted fabric region 1A to 1D is knitted by the front yarn a and the back yarn b and the thermally fusible yarn c combined therewith, whereas the knitted fabric region 1E is knitted by the front yarn a and the back yarn b, alternatively by the front yarn a and the back yarn b and a yarn other than the thermally fusible yarn c combined therewith (see FIGS. 1 to 4).

The upper 1 that has been knitted in the above manner is then folded along a longitudinal center line and introduced into a heat press 100 and 101 shown in FIGS. 14 and 15. The upper 1 is heated on opposite sides thereof for a predetermined time with the opposite sides of the upper 1 sandwiched between the heat press 100 and 101 as shown in FIGS. 14 and 15. Here, a side surface (e.g. a medial side surface 1F) of the upper 1 is heated by the heat press 100 and the other surface (e.g. a lateral side surface 1F′) of the upper 1 is heated by the heat press 101. During heat press, a metal or plastic plate 110 may be inserted into the upper 1 for holding the upper 1.

Heating temperature at the heat press is determined according to the melting point of the thermally fusible yarn c included into the knitted fabric of the upper 1 and it is set at a temperature equal to or higher than the melting point of the thermally fusible yarn c. In the case of “ELDER®” used as the thermally fusible yarn c in the present embodiment, the melting point is 110-120° C. Therefore, the heating temperature at the heat press is set at a temperature higher than 120° C. for example. By such heat treatment, the thermally fusible yarn c is fusion-bonded and cured. As a result, the knitted fabric including the thermally fusible yarn c is hardened. However, according to the present invention, since the thermally fusible yarn c is disposed on the upper outside surface (see FIG. 10), after the heat treatment, the upper outside surface is made harder than the upper inside surface in each of the knitted fabric.

After the heat treatment, as shown in FIGS. 5 to 8, an outsole 12 is fixedly attached to a bottom surface of the upper 1 via a midsole 11 formed of a soft elastic material such as EVA (Ethylene Vinyl Acetate Copolymer), PU (polyurethane), and the like. Also, in the present invention, a reinforcement member 13 is fitted to a lower portion of the upper 1 along the outer perimeter thereof. In such a manner, a sports shoe 10 is assembled.

As mentioned above, according to the upper 1 of the present embodiment, the knitted fabric region 1A to 1D (see vertical lines) includes the thermally fusible yarn c and after knitting the upper 1 it is heated at a temperature equal to or higher than the melting point of the thermally fusible yarn c. Through such heat treatment, the thermally fusible yarn c disposed on the upper outside surface in each of the knitted fabric region 1A to 1D is fusion-bonded and cured in each of the knitted fabric 1A to 1D. As a result, the upper outside surface is made harder than the upper inside surface in each of the knitted fabric region 1A to 1D after the heat treatment. Thereby, holdability of the upper can be improved and wearer's touch on the foot can be enhanced. Moreover, by hardening the knitted fabric region 1A to 1D including the thermally fusible yarn c, solidity (i.e. three-dimensional shape retainability) of the upper 1 formed of the knitted fabric can be improved. Thereby, workability at the time of assembly of the sports shoe 10 using the upper 1 can be improved. Furthermore, by hardening the outer surface side of the upper 1 including thermally fusible yarn c, the surface of the upper 1 can be reinforced.

On the other hand, the knitted fabric region 1E (see white void areas defined by outlines) having no thermally fusible yarn c is not hardened even after the heat treatment and a certain degree of elasticity is thus secured in the knitted fabric region 1E, thereby maintaining fitness or fitting properties of the upper 1. Especially, in the event that the knitted fabric region 1E is formed of float knitting, since the knitted fabric region 1E can permit a certain degree of elasticity and restrain further extension after it has extended to some degree, it can secure a moderate holdability with fitting properties during exercise maintained.

In the above-mentioned embodiment, an example was shown in which the knitted fabric region 1A to 1D extends integrally with each other in a longitudinal direction from the heel portion through the midfoot portion to the forefoot portion of the upper 1, but the present invention is not limited to such an example. The knitted fabric region 1A to 1D is not necessarily integrated with each other in the longitudinal direction.

In the above-mentioned embodiment, as an example of the knitted fabric region 1A to 1D of the upper 1, pile knitting, back-thread tuck stitching and float knitting were shown, but application of the present invention is not limited to these fabrics and the present invention also has application to other fabrics of various kinds.

In the above-mentioned embodiment, knitting patter by circular knitting was shown, but the present invention also has application to other knitting patterns such as plain knitting, rib knitting and the like.

In the above-mentioned embodiment, as a heating apparatus of the upper 1, the heat press having a structure shown in FIGS. 14 and 15 was used. However, a heat press having a structure different from the structure of FIGS. 14 and 15 can be used. Also, not only a dry-heat type but also a moist-heat type can be used.

Those skilled in the art to which the invention pertains may make modifications and other embodiments employing the principles of this invention without departing from its spirit or essential characteristics particularly upon considering the foregoing teachings. The described embodiments and examples are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. Consequently, while the invention has been described with reference to particular embodiments and examples, modifications of structure, sequence, materials and the like would be apparent to those skilled in the art, yet fall within the scope of the invention.

Upper Structure for a Sports Shoe

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