The present invention relates to shoes with improved fitting property.
Functions required of shoes, such as athletic shoes, include fitting property. The fitting property may be improved by, for example, reducing wrinkle occurrence, decreasing contact pressure values, improving contact condition between the foot and the shoe upper, and improving the upper to better follow foot deformation behavior.
Generally, the upper is designed in consideration of a stationary shape of a foot. In conventional shoes, the entire upper is made of a low-stiffness material in an attempt to decrease contact pressure values. However, the upper made of a low-stiffness material cannot distribute shoe lace tightening force which is exerted at eyelets throughout the entire upper, resulting in poor contact condition between the foot and the upper.
Another attempt which has been tried was to reduce large wrinkle occurrences which can develop in the upper during activities. Specifically, a shoe includes a mesh member which is reinforced with a urethane resin for dispersed occurrence of small wrinkles. However, the arrangement does not provide a fundamental solution to the object of reducing wrinkles.
Another attempt to reduce wrinkles in the upper of a shoe for improved fitting property between the shoe and the foot is disclosed in Patent Literature 1.
According to this shoe disclosed in Patent Literature 1, a stretching fabric is used in the upper. The stretching fabric is stretched, and then integrated with the sole under this state. Since the upper of the shoe is under a shrinking force, there is less occurrence of wrinkles in the upper even when the foot is bent during activities such as running.
One consideration to be noted here is that during activities, the shape of the foot is constantly changing. In other words, during activities, the upper is often not able to follow the foot deformation behavior, resulting in separation of the shoe sole from the foot. On the contrary, there can also be cases where the upper works as a constraint on natural foot deformation behavior. Therefore, when the upper is considered as a part which makes the sole follow the foot, it is desirable that the upper is able to change its shape following the foot deformation behavior during activities.
In other words, fitting property is required of the shoes because the foot changes its shape during activities. In order to improve the fitting property, it is desirable that the upper has a strain distribution which is similar to a strain distribution in the foot during activities.
The applicant of this invention has already proposed athletic shoes with improved fitting property (see Patent Literature 2).
The athletic shoes disclosed in Patent Literature 2 includes a sole which absorbs landing impact; and an upper which covers the instep of the foot. The upper includes a first opening which exposes the foot upward when the shoe is worn, and a second opening which is closed with a tongue piece. The two openings are continuous with each other in a fore-aft direction. The upper includes an inner stretching region covering part of an inner-side surface of the foot, an outer stretching region covering part of an outer-side surface of the foot, a front region ahead of the two stretching regions, and a rear region behind the two stretching regions. Each of the stretching regions has a smaller Young's module than the front region and the rear region. Also, the outer stretching region covers a region ranging from the fifth metatarsal distal bone head or a region nearby to the second opening.
The arrangement described above, i.e., that the outer stretching region is on an area essentially at or near an upper end of the fifth metatarsal distal bone head, means that a stretching material covers the region of the foot where strain distribution can change drastically. This allows the upper to change its shape in accordance with shape changes of the region and improves fitting property.
The shoes disclosed in Patent Literatures 1 and 2 still cannot sufficiently reduce occurrence of wrinkles. The present invention was made to eliminate the problem described above, with an object to provide shoes with good fitting property having such an advantage as reduced occurrence of wrinkles.
The present invention provides a shoe including: a sole which absorbs landing impact; and an upper which covers an instep of a foot. In this arrangement, the upper has a first opening through which the foot is inserted when wearing the shoe, and the upper is partly or entirely made of a material which has negative Poisson's ratios.
The upper may also have a second opening closed by a tongue piece above the instep. In this arrangement, the first opening and the second opening are continuous with each other in a fore-aft direction, and the upper is partly or entirely made of the material which has negative Poisson's ratios, excluding a tightening region near the second opening.
The material which has negative Poisson's ratios may be provided by a single layer of negative Poisson's ratios structure.
Also, the material which has negative Poisson's ratios may be provided by a plurality of layers, with at least one of the plurality of layers having the negative Poisson's ratios structure. For example, a material which has a greater stiffness than a main material of the upper is used to form the layer of the negative Poisson's ratios structure, and on one side thereof, there may be laminated another layer which may be a mesh material having a lower stiffness than the material of said greater stiffness or a highly stretchable material. Also, a material which has a greater stiffness than a main material of the upper is used to form the layer of the negative Poisson's ratios structure, and on both sides thereof, there may be laminated another layer which may be a mesh material having a lower stiffness than the material of said greater stiffness or a highly stretchable material.
The negative Poisson's ratios structure may be a net-like structure made of a plurality of rows of square-shaped frames, with each square-shaped frame having a pair of two mutually opposing sides out of four being close from each other in their center regions, and the rows being offset from each other by a half of a pitch of the square-shaped frame.
The upper has an toe region, where the material having negative Poisson's ratios may be used so that the row direction of the negative Poisson's ratios structure is oriented in a fore-aft direction of the shoe.
The upper has a region of the first metatarsophalangeal joint, where the material having negative Poisson's ratios may be used so that the row direction of the negative Poisson's ratios structure is oriented in an up-down direction of the shoe.
The upper has an region of the fifth metatarsophalangeal joint, where the material having negative Poisson's ratios may be used so that the row direction of the negative Poisson's ratios structure is oriented in an up-down direction of the shoe.
The upper has a heel region, where the material having negative Poisson's ratios may be used so that the row direction of the negative Poisson's ratios structure is oriented in an up-down or fore-aft direction of the shoe.
The upper has a tongue piece, where the material having negative Poisson's ratios is used so that the row direction of the negative Poisson's ratios structure is oriented in a fore-aft direction of the shoe
The upper has a midfoot region, where the material having negative Poisson's ratios may be used so that the row direction of the negative Poisson's ratios structure is oriented in a fore-aft direction of the shoe.
The present invention makes it possible to improve fitting property by making the upper partly or entirely of a material which has negative Poisson's ratios. Specifically, wrinkle occurrence is reduced, contact pressure values are decreased, contact condition between the upper and the foot is maintained, and the foot and the upper deform their behavior in the same pattern, resulting in better fitting property.
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted here that throughout the drawings the same or equivalent parts and components will be indicated with the same reference symbols, and in order to avoid redundancy in description, their description will not be repeated.
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The tongue piece 5 is sewn to the upper 2 ahead of the second opening 4. At a center of an upper surface of the tongue piece 5, a tube-like loop 53 is provided. When the shoe is worn, the shoe lace 6 is inserted through the loop 53 as shown in
The upper 2 has toe region 21 between the toe and the tongue piece 5; a fore-foot region 22; a heel region (ankle sponge) 23 around the first opening 3; a heel region (heel counter) 24 between the heel region (ankle sponge) 23 and the sole 1; an region of the fifth metatarsophalangeal joint 22a; and a midfoot region 25 between a region of the first metatarsophalangeal joint 22b and the heel region 23. The fore-foot region 22 includes the region of the fifth metatarsophalangeal joint 22a at a location corresponding to the antithenar, and the region of the first metatarsophalangeal joint 22b at a location corresponding to the hallux. A line marker 27 is provided in the midfoot region 25. It should be noted here that the region of the fifth metatarsophalangeal joint 22a and the region of the first metatarsophalangeal joint 22b may be collectively called the fore-foot region 22.
Along two sides of the second opening 4, a pluralities of eyelet regions 51 and loop regions 52 are provided. The shoe lace 6 is inserted through these eyelet regions 51 and the loop regions 52 and then the lace is tightened. These eyelet regions 51 and loop regions 52 constitute a tightening region 50 for transmitting a tightening force of the lace. For transmitting the tightening force of the lace, the tightening region 50 is made of a material having a predetermined stiffness.
When the shoe is worn around a foot, the shoe lace 6 in
When the shoe is worn and the lace is tightened, as shown in
As a simulation of the upper 2 covering the foot, assume a plane covering a tree-dimensional object. Then it is understood that as shown in
A contact pressure value in this state is given by the following calculation:
Contact pressure value=Rx·Fx+Ry·Fy (1)
where, R represents curvature whereas F represents external force.
When a material which has negative Poisson's ratios, on the other hand, is pulled in Direction Y, the material also stretches in Direction X, so it can cover the foot without being pulled in Direction X.
As described above, if a material which has negative Poisson's ratios is used, it becomes possible to cover the foot by pulling it in Direction Y without pulling in Direction X. This means that when calculating a contact pressure value with the Mathematical Expression (1), the first item has a value of zero. Therefore, if a material which has negative Poisson's ratios is used, it becomes possible to reduce the contact pressure value when covering the foot, and thereby improve pressing contact onto the foot.
The present invention was made based on the above-described knowledge, and provides an arrangement that except for the tightening region 50 which is near the second opening 4 and serves as a region for transmitting the lace tightening force, the upper 2 is partly or entirely made of a material having negative Poisson's ratios. The arrangement described above makes it possible to transmit the lace tightening force, improve contact condition between the upper and the foot, decrease the contact pressure values, and improve fitting property.
Among various proposals for a material 7 which has negative Poisson's ratios including those having a special, honeycomb-like structure and those having a composite, artificial structure called bubble structure, etc., one example is as shown in
The material 7 which has negative Poisson's ratios and is used for the upper 2 may be provided by a single layer of a material which has the negative Poisson's ratios structure as shown in
The material which has negative Poisson's ratios and is provided as a laminated member made by laminating a plurality of layers includes a layer having negative Poisson's ratios structure; and the other layers laminated there on provided by materials which do not obstruct shape changes of the negative Poisson's ratios structure layer so that the laminated member as a whole has negative Poisson's ratios.
As a simulation of an action which occurs during activities, consider a case where the heel is raised while a forefoot region of the sole 1 is kept in contact with the ground. Since the toe region 21 is squeezed in the anterior-posterior direction while stretched in the mediolateral direction, wrinkles develop. If a material 7, which has negative Poisson's ratios, is disposed at the toe region 21 of the upper 2, these wrinkles do not develop because the material is squeezed in the mediolateral direction simultaneously when squeezed in the anterior-posterior direction. Therefore, use of a material which has negative Poisson's ratios makes it possible to reduce occurrence of wrinkles.
When landing on the heel during running activities, as shown in broken lines in
When the heel region (ankle sponge) 23 of the upper 2 is compressed in Direction Y, a gap between the heel region 23 of the upper 2 and the foot is increased, which can pose a concern of reduced fitting property of the heel region 23. However, if a material which has negative Poisson's ratios is disposed at the heel region 23, the heel region 23 of the upper 2 is stretched in Direction Y simultaneously as it is stretched in Direction X at the time of shape change shown in broken lines in
As a further consideration, when landing on the heel in running activities, the toe region of the foot is compressed in the mediolateral direction and the anterior-posterior direction. As the foot's entire bottom surface lands, the toe region of the foot stretches in the mediolateral direction and the anterior-posterior direction, with the midfoot region being stretched in the mediolateral direction and the anterior-posterior direction on the inner-side while the outer-side of the midfoot region is compressed in the mediolateral direction and the anterior-posterior direction. When the foot kicks on the ground, the toe region of the foot is compressed in the mediolateral direction and the anterior-posterior direction, with the midfoot region compressed in the mediolateral direction and the anterior-posterior direction on the inner-side while the outer-side of the midfoot region is stretched in the mediolateral direction and the anterior-posterior direction. Hence, if a material which has negative Poisson's ratios is inserted to the toe region 21 or the midfoot region 25 of the upper 2, the upper 2 is stretched in both the mediolateral direction and the anterior-posterior direction simultaneously, or compressed in both the mediolateral direction and the anterior-posterior direction simultaneously. In other words, the toe region, the midfoot region and the upper 2 deform their behavior in the same pattern throughout all phases of running activities, and therefore natural movements of the foot is not obstructed by the upper 2.
Next, description will cover an example where the material which has negative Poisson's ratios is used in various places in the upper 2. Reference will be made to
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In addition to the upper 2, the material should be used as the shoe lace 6 by rolling a sheet of negative Poisson's ratios material into a three-dimensional string. By using the material here, the lace becomes less prone to loosening.
In the embodiments described thus far, the shoe lace 6 is routed through the eyelet regions 51 and the loop regions 52 in the tightening region 50 and then the lace is tightened. Besides such a configuration as the above, the present invention can also be applied to shoes having other lace-tightening designs. Examples include a tightening region 50 provided with buckle (s) so that a belt (s), for example, is inserted through the buckle(s) and then tightened.
All of the embodiments disclosed herein are to show examples, and should not be considered as of a limiting nature in any way. The scope of the present invention is identified by the claims and is not by the descriptions of the embodiments given hereabove, and it is intended that the scope includes all changes falling within equivalents in the meaning and extent of the Claims.
This application is a continuation of U.S. application Ser. No. 14/910,367 filed on Feb. 5, 2016, which is a national stage under 35 USC 371 of PCT/JP2013/071415 filed on Aug. 7, 2013, the disclosures of which are incorporated herein by reference.
Number | Date | Country | |
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Parent | 14910367 | Feb 2016 | US |
Child | 17206759 | US |