LAST, METHOD FOR PRODUCING LAST, AND METHOD FOR PRODUCING SHOE UPPER

Provided is a last for shaping a shoe upper. The last includes at least an outer peripheral portion composed of a plastic material that is reversibly transformed between a solid state where the plastic material has a certain shape when the shoe upper is shaped, and a plasticized state where the plastic material has fluidity and is thereby deformable.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Applications No. 2019-191353 filed on Oct. 18, 2019 and No. 2020-084988 filed on May 14, 2020, the disclosures of which are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to a last for shaping a shoe upper, a method for producing the last, and a method for producing the shoe upper.

BACKGROUND OF THE INVENTION

In producing custom-made shoes tailored to a user's feet, lasts are exclusive for the user. Thus, after shoe uppers are shaped using lasts to produce shoes, the lasts are no longer used unless stored for future use.

US 2018/0014609 A discloses that footwear is produced in a portable housing. US 2016/0206049 A discloses a last pre-form that is composed of a shape memory polymer and thereby re-shapeable. CN 109732913 A discloses that a last is formed by 3D printing. U.S. Pat. No. 1,550,232 B discloses a last including paper pulp thereinside.

However, none of the abovementioned prior art documents specifically and explicitly discloses recycling of lasts that are no longer used.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a recyclable last, a method of producing the last, and a method of producing a shoe upper.

The present invention provides a last for shaping a shoe upper, the last including: at least an outer peripheral portion composed of a plastic material that is reversibly transformed between a solid state where the plastic material has a certain shape when the shoe upper is shaped, and a plasticized state where the plastic material has fluidity and is thereby deformable.

The present invention further provides a method for producing a last for shaping a shoe upper, the method including forming the last by layering a pulp aggregate in which a plurality of pulp materials are aggregated, in an inward and outward direction with reference to a foot of a shoe wearer, by 3D printing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

An embodiment of the present invention will be exemplified with reference to the drawings. Hereinafter, regarding the term representing the direction “inward and outward direction”, the inward direction is a direction toward a foot of a shoe wearer, and the outward direction is a direction toward the outside of the shoe. Further, when a description is given below on a shoe upper2before and after being shaped, the shoe upper2before being shaped can be referred to as an unshaped upper2A while the shoe upper2after being shaped can be referred to as a shaped upper2B for separate identification of the respective states.

A last (shoe last)1of this embodiment is mainly not a last for shoes for mass production, but a custom-made last1tailored to a user's foot F. However, the present invention does not intend to completely deny its application to a last for shoes for mass production, but can be applicable thereto. The last1can be produced at a shoe retailer, or can be produced at a factory located away from the retailer by transmission and reception of 3D printing data and data on a user's foot using a communication device, as will be described later. The last1of this embodiment has at least an outer peripheral portion (i.e., a portion coming into contact with the shoe upper2when the shoe upper2is shaped) composed of a plastic material. The “plastic material” herein means a material that is reversibly transformed between a solid state where the material has a certain shape (see the shape of the last1shown inFIG. 1B) when the shoe upper2is shaped by placing a material of the shoe upper2(i.e., an unshaped upper2A) on the last1followed by heating or the like for shaping, and a plasticized state where the material has fluidity (seeFIG. 1C). Any material that is irreversibly transformed is excluded from examples of the “plastic material”. The “fluidity” means a property of liquid (or a material similar to liquid), the property allowing the liquid or the material similar to liquid to freely change its form (outer shape). The shoe upper2is, for example, formed of fabric, and in this embodiment formed of fabric composed of a heat-shrinkable fiber sheet.

The plastic material in this embodiment includes a solid content aggregate in which a plurality of solid contents are aggregated, and a shaping material mixed in the solid content aggregate and used for solidifying the solid content aggregate into the certain shape. In this embodiment, a pulp material (i.e., pulp pieces formed into particles or fibers that each are smaller than the last1as a whole) is used as the solid contents. That is, the solid content aggregate in this embodiment is a pulp aggregate. This configuration allows the last1to be formed of the pulp material, which is a general paper material, and thus to be formed of a readily available material.

The shaping material is dissolved from the solid state to thereby allow the plastic material to have fluidity. The dissolution occurs, for example, by adding a different material (water in this embodiment) to the shaping material, by heating the shaping material, or by irradiating the shaping material with light (e.g., ultraviolet rays). The material used as the shaping material is a water-soluble material, such as starch paste or a water-soluble resin, which exhibits fluidity when water is added thereto. The shaping material is, for example, a liquid in the initial state, and turns to a solid when left for a certain period of time in the state of being in contact with the pulp aggregate. The shaping material is thereafter caused to dissolve so that a liquid with the solid pulp aggregate mixed therein can be made. When a water-soluble shaping material is used, the shaping material is dissolved in water and thereby plasticized; thus, it is advantageous that no special chemical or apparatus is required for dissolution.

A mixing ratio between the pulp aggregate and the shaping material can be determined in consideration, for example, of hardness required when the outer peripheral portion of the last1is used (i.e., before and after the shoe upper2is shaped), the roughness of the surface of the last1, atmospheric humidity when the last1is used, and a period of time required for the dissolution.

The last1thus configured can be transformed from the solid state to the plasticized state after the shoe upper2is shaped, and thereafter transformed back to the solid state. This transformation occurs reversibly. Thus, the last1is recyclable.

The last1is formed of the pulp aggregate layered in the inward and outward direction. The last1can be multi-layered or single-layered. The last1, which can be shaped by the layering, can be formed without the use of a forming mold. Thus, the last1can be, for example, shaped using a 3D printer as shown inFIG. 2.

The last1may be solid, but is preferably hollow inside (see the partial cross section inFIG. 2). In the case where the last1is formed to be hollow, a body11that includes the plastic material is formed to surround an internal space1a,which corresponds to a hollow portion of the last1. The last1formed to be hollow can still ensure the strength by allowing the body11to have a certain thickness, and thus has no functional problem. The last1formed to be hollow eliminates the necessity to arrange a material in the center portion thereof, and can thus save the material. This configuration can save the time required for forming the last1. Further, this configuration can save the weight of the last1, and therefore allows the last1to be easily handled. As described above, this configuration has various advantages.

As shown inFIG. 3A, the last1can include a central part12and a peripheral part13. The central part12is formed in advance as a core member of the last1, and is constantly held in a solid state. The central part12may be solid or hollow. The central part12formed to be hollow can save the weight of the last1. The peripheral part13is formed on an outer peripheral portion of the central part12. The peripheral part13is composed of the plastic material. That is, in this configuration, the central part12is positioned in the internal space1ain the aforementioned configuration. This configuration can save the time required for forming the last1, similar to the aforementioned configuration. This configuration can reduce the amount of the plastic material used for forming the last1as compared with the configuration in which the last1is solid and entirely formed in a uniform manner. In the case where shoes are produced at a factory, use of the central part12as a core material allows only the central part12, which is slightly smaller than the last1, to be stored in the factory for a long period of time. Thus, the number of central parts12stored per specific space can increase as compared with the case where the lasts1are entirely kept, and the storage space can be thereby saved. Even when the lasts1of different sizes are required, their central parts12can be made to have the same shape (size) so that the necessity to store the lasts1by size is eliminated.

In the case where the last1includes the central part12, the central part12can be formed of a material of higher heat conductivity than that of the peripheral part13. For example, the central part12can be formed of metal (e.g., an aluminum alloy). This configuration causes the central part12of the last1to be heated when the shoe upper2is heated for shaping (seeFIG. 4), and thereby allows the shoe upper2to be heated also from the side of the central part12(that is, the unshaped upper2A is to be heated from both inside and outside). This configuration can thus shorten the heating time compared to the case where heating is performed only from outside, and allows the shoe upper2to be shaped efficiently (i.e., within a short time).

As shown inFIG. 3B, the last1can include the body11, and the protective part14having a layer shape or a film shape and covering the outer periphery (outer surface) of the body11. As aforementioned, the body11corresponds to: a portion surrounding the internal space1ain the case where the last1is hollow; the entire last1(except the protective part14) in the case where the last1is solid; and the peripheral part13in the case where the last1includes the central part12and the peripheral part13(seeFIG. 3A). With this configuration, the body11can be protected from damage by the protective part14. The protective part14can be configured to allow the last1to be resistant to heat or ultraviolet rays. Further, the protective part14can be configured to be removed from the body11. To allow the protective part14to be removed, for example, the protective part14is attached to the body11using adhesive configured to be removable after being attached, or the protective part14composed of a material having small adhesiveness to the body11is formed. This configuration allows the protective part14when attached to the last1to protect the body11, and at the same time allows the protective part14when peeled off the last1to make the body11easily recyclable.

Examples of the protective part14include a metal film (e.g., aluminum film), a ultraviolet curing resin that is applied and cured (e.g., epoxy resin), a silicon resin, and rubber. The protective part14may be a layer composed of small particles (e.g., sand) blown on the outer periphery of the body11. The protective partl4may be a film formed on the body11by soaking the body11in liquid resin. Further, the protective part14can be a film formed by blowing liquid resin onto the body11, or by applying liquid resin to the body11using a brush, a roller or the like.

Next, a method for producing the last1will be described. The last1is formed by layering the plastic material (mixture of the pulp aggregate and the shaping material) in the inward and outward direction by 3D printing. This forming is performed so that the last1has a hollow shape, as shown in the partial cross section inFIG. 2. In the case where the last1includes the central part12and the peripheral part13, the portion serving as the peripheral part13is layered on the outer periphery of the central part12(seeFIG. 3A). Use of the 3D printing technique allows the last1to be easily formed without use of a forming mold. 3D printing is carried out using a 3D printer including a nozzle N as shown inFIG. 2. The mixture in the plasticized state is discharged through the nozzle N and sequentially piled up from the bottom as shown inFIG. 2to shape the last1.FIG. 2shows a last1bbeing shaped.

In the case where the last1is formed by 3D printing, a forming speed of the last1bthat is being shaped can be considered. The entire last1can be formed at a uniform speed; or for example, for the purpose of shortening the shaping time, an instep portion of the last1, which corresponds to a portion of a shaped upper2B that significantly affects wearing feeling of the user, can be precisely shaped at a low speed and the other portions can be coarsely shaped at a high speed. Further, the outer layer of the last1with which the shoe upper2comes into contact at the time of being shaped can be precisely shaped at a low speed and the inner layer thereof can be coarsely shaped at a high speed. Still further, the last1can be shaped to have the outer layer of high density and the inner layer of low density.

Before the last1is formed, a data acquiring step of acquiring the user's foot shape data, and a data generating step of generating 3D printing data from the user's foot shape data acquired are performed. Thereafter, a last forming step of layering the pulp aggregate based on the generated 3D printing data is performed. Performing these steps enables forming the custom-made last1tailored to the user's foot F.

The 3D printing data is created based on the user's foot shape data, which is individually generated for each of a plurality of users. The 3D printing data thus generated allows the shoe upper2to be finely customized for each user.

The user's foot shape data refers to, for example, measurement data of each part of the user's foot F generated from image data obtained by capturing an image of the user's foot F as shown inFIG. 1A. Thus, the user's foot shape data can be easily generated using, for example, a digital camera or a smartphone P (seeFIG. 1A). In the case, for example, where the smartphone P is used, the foot shape data can be generated based on the image data by software that is installed in advance in the smartphone P. The foot shape data can also be created by calculation using both the captured image data and data owned by a shoemaker in their server.

The image data can be acquired at the user's home or at a retailer (dealer) the user visits. In this case, the image data is transmitted to the server of a shoemaker and the foot shape data is generated at a factory of the shoemaker, so that the lasts1and shoes conforming thereto can be subsequently produced at the factory. It is also possible to acquire the image data at a retailer and produce the lasts1and shoes conforming thereto at the retailer. It is of course possible to produce the lasts1and shoes conforming thereto respectively at different places. The retailer is not limited to a fixed store but may be a mobile store using a car or a trailer.

A dissolving step is performed when the last1is no longer required after being used for shaping the shoe upper2. In the dissolving step, the last1after being used is dissolved and fluidized to obtain a dissolved material1F (seeFIG. 1C).FIG. 1Cshows the state where the dissolved material1F is placed in a container. The shape of the container for retaining the dissolved material1F therein is no particularly limited. The dissolved material1F is adjusted to have such fluidity as to be capable of being discharged to the outside through the nozzle N of the 3D printer. In the case where the last1includes a water-soluble shaping material, the last1after being used (i.e., after being used for shaping the shoe upper2) is fluidized by adding water thereto. The dissolved material1F in this case is composed of the pulp material as a dispersoid that is dispersed in water as a dispersion medium. The water constituting the dissolved material1F includes the shaping material (e.g., starch paste) dissolved therein. The shaping material is additionally dissolved in the dissolved material1F as required. Further, a curing accelerator for accelerating curing after discharged through the nozzle N can be added to the dissolved material1F. To prevent the pulp material from being deposited in the container, a chemical can be added to the dissolved material1F, or the dissolved material1F can be stirred in the container. The dissolving step thus performed allows the solid content aggregate (pulp aggregate) to turn back to the plasticized state, and enables 3D printing using the aggregate in the plasticized state. The last1after being used can be thus recycled as a last1for another user.

To carry out the dissolving step within a short period of time, hot water can be added to the last1after being used. Further, a parting line can be in advance formed on the last1at the time of shaping the last1. Still further, a mechanical device such as a cutter (e.g. shredder) or a device for crushing the aggregates or the like of the last1can be used before or after adding cold or hot water to promote dissolution by the cold or hot water.

Next, a method for producing the shoe upper2using the last1will be briefly described. For example, a material of the shoe upper2(i.e., the unshaped upper2A) composed of a fiber sheet including heat-shrinkable yarns is prepared. Then, carried out are a first shaping step of placing the unshaped upper2A on the last1, and a second shaping step of shaping the unshaped upper2A in conformity with the shape of the last1by heating to obtain the shaped upper2B, as shown inFIG. 4. A steam heating means is used as a heating means in the second shaping step. As schematically shown inFIG. 4, for example, the unshaped upper2A is placed in a heating box31, and heated with high-temperature steam32discharged from the inner surface of the heating box31. This steam heating allows the unshaped upper2A to be entirely and uniformly heated. This configuration allows the unshaped upper2A to be uniformly deformed in conformity with the shape of the last1to obtain the shaped upper2B. In the second shaping step, hot-air heating, hot water heating, or the like can be used other than the steam heating. Further, the unshaped upper2A can be heated not entirely but partially.

Performed after the second shaping step is a sole attaching step, in which the shaped upper2B is attached to a separately prepared sole by, for example, adhesive. Other than adhesive, heat fusion bonding, for example, can be applied to perform the sole attaching step simultaneously with the second shaping step. In this case, the heat fusion bonding can be efficiently performed using the last1having the central part12formed of a material of high heat conductivity (for example, a metal such as aluminum, copper, or stainless steel). Forming a shoe tongue, trimming a wearing opening, making eyelets for passing shoelace therethrough, attaching decoration members and tags, printing a logo, and attaching an insole can be performed as appropriate, during any of the aforementioned steps or after all the steps.

Hereinafter, the configurations and operational effects according to the embodiment of the present invention will be summarized. Provided in this embodiment is a last1for shaping a shoe upper2, the last1including: at least an outer peripheral portion composed of a plastic material that is reversibly transformed between a solid state where the plastic material has a certain shape when the shoe upper2is shaped, and a plasticized state where the plastic material has fluidity and is thereby deformable.

This configuration allows the last1to be transformed from the solid state to the plasticized state after the shoe upper2is shaped, and transformed back to the solid state, thereby allowing the last1to be recyclable.

The plastic material may include a pulp aggregate in which a plurality of pulp materials are aggregated, and a shaping material for solidifying the pulp aggregate into the certain shape, and the shaping material may be configured to be dissolved from the solid state to thereby cause the plastic material to have fluidity.

This configuration allows the pulp material, which is a general paper material, to be used, and thus allows a readily available material to be used.

The shaping material can be water-soluble.

This configuration allows the shaping material to be dissolved in water, and thus eliminates the necessity of preparing special chemicals or devices for dissolution.

The last1can be formed of the pulp aggregate layered in an inward and outward direction with reference to a foot of a shoe wearer.

This configuration allows the last1to be formed by layering without a use of a forming mold, and thus to be shaped, for example, by 3D printing.

The last1can be hollow inside.

This configuration eliminates the necessity to arrange a material in the center portion of the last1, and can thus save the material.

The last1can further include: a central part12formed in advance as a core and constantly held in the solid state; and a peripheral part13that is formed on an outer peripheral portion of the central part12and that is formed of the plastic material.

This configuration can shorten the time required for forming the last1, and can reduce the amount of the plastic material used, as compared with the configuration in which the last1is entirely uniformly formed.

The central part12may be formed of a material having a higher heat conductivity than that of the peripheral part13.

This configuration allows the shoe upper2to be heated also from the central part12side at the time of shaping the shoe upper2by heating, and thus allows the shoe upper2to be efficiently shaped.

The last1can further include: a body11including the plastic material; and a protective part14covering an outer periphery of the body11.

This configuration allows the protective part14to protect the body11.

The protective part14may be capable of being removed from the body11.

This configuration allows the protective part14to be removed from the last1, and thus allows the body11to be easily recyclable.

Provided in this embodiment is a method for producing a last1for shaping a shoe upper2, the method including: forming the last1by layering a pulp aggregate in which a plurality of pulp materials are aggregated, in an inward and outward direction with reference to a foot of a shoe wearer.

The production method thus configured allows the last1to be easily formed without a use of a forming mold.

The method for producing the last1can further include forming the last1to be hollow by the 3D printing.

The production method thus configured can shorten the time required for forming the last1, and can save the material.

The configuration of the method for producing the last1can be such that the last1includes: a central part12formed in advance as a core; and a peripheral part13formed on an outer peripheral portion of the central part12. According to this method, a portion to be formed by the 3D printing can be limited to the peripheral part13.

The production method thus configured can shorten the time required for forming the last1, and can reduce the amount of the plastic material used, as compared with the configuration in which the last1is entirely uniformly formed.

The method for producing the last1can further include: acquiring a user's foot shape data; generating 3D printing data from the user's foot shape data; and forming the last by layering the pulp aggregate based on the 3D printing data.

The production method thus configured allows the last1to be formed tailored to the user's foot.

The method for producing the last1can further include creating the 3D printing data based on the user's foot shape data individually generated for each of a plurality of users.

The production method thus configured allows the shoe upper2to be customized for each user.

The user's foot shape data can be generated from image data obtained by capturing an image of the user's foot.

The production method thus configured allows the foot shape data to be easily generated using, for example, a digital camera or a smartphone P.

The configuration of the method for producing the last1can be such that the last1includes a water-soluble shaping material for solidifying the pulp aggregate into a certain shape, and that the method further includes adding water to the last1after being used to fluidize the last1.

The production method thus configured allows the last1after being used to be recyclable as a last1for another user.

Provided in the aforementioned embodiment is a method for producing a shoe upper2, the method including: placing an unshaped upper2A on the last1, the unshaped upper2A composed of a fiber sheet including heat-shrinkable yarns; and shaping the unshaped upper2A in conformity with the shape of the last1by heating to obtain a shaped upper2B.

The production method thus configured allows the shoe upper2to be produced using a recyclable last1.

The present invention has been described by taking an embodiment, but the description is merely an exemplification. The last1, the method for producing the last1, and the method for producing the shoe upper2, according to the present invention, are not limited to the aforementioned embodiment. Thus, various modifications can be made for the last1, the method for producing the last1, and the method for producing the shoe upper2, according to the present invention, without departing from a gist of the present invention. The modifications include, for example, partially replacing or partially omitting a plurality of elements constituting the aforementioned embodiments, and combining an element pertaining to an embodiment with an element pertaining to another embodiment as appropriate. The modifications also include combining matters pertaining to common technical knowledge regarding the last1, the method for producing the last1, and the method for producing the shoe upper2.

For example, the plastic material may be a resin. In the case where a thermoplastic resin is used as the resin, the thermoplastic resin can be transformed to a plasticized state by being heated and to a solid state by being cooled.

The aforementioned embodiment has been described by taking, for example, the case where the pulp material is used as the solid content, without limitation thereto. For example, wood pieces (e.g., wood chips), bamboo pieces, natural fiber pieces (e.g., yarn waste or cut pieces of plant fibers), resin pieces (preferably heat-resistant resin pieces), metal pieces, paper pieces (larger than the pulp material and kept in a paper form), fabric pieces, plant pieces (e.g., cut pieces of dry grasses), sand, soil, or mud can be used.

The shaping material may be any material molten by heat or dissolved in a solvent other than water.

In the aforementioned embodiment, a description has been given on, for example, the method for producing the last1in which the material is layered by 3D printing, but the last1may be formed by, for example, producing a forming mold4shown inFIG. 5Bbased on the foot shape data and pouring a plastic material into the forming mold4. The forming mold4can be formed by 3D printing.

In this case, as shown inFIG. 5B, the forming mold4can be formed by combining a first forming mold4ahaving a recess41formed to correspond to one side (for example a right side) in the width direction of the last1and a second forming mold4bhaving the recess41formed to correspond to the other side (for example a left side) in the width direction of the last1.

First, as shown inFIG. 5A, the recess41is formed in each of the first forming mold4aand the second forming mold4busing, for example, a cutting tool C, so as to conform to the shape of the last1to be formed. The forming mold4before being cut may have a small recess formed in advance. In this case, the recess to be formed in advance may have a size corresponding to the standard size of the last1so that additional processing using, for example, a cutting tool C can be minimized. The completed forming mold4is as shown inFIG. 5B. The last1is formed as shown inFIG. 5Cby pouring the plastic material into the recess41of the forming mold4.

In pouring the plastic material into the forming mold4, the plastic material can be poured into each of the first forming mold4aand the second forming mold4bto form a pair of last components (left and right components), which are subsequently joined together to form the last1, or the plastic material can be poured into the forming mold4of after the first forming mold4aand the second forming mold4bare joined together, to form the last1.

This forming mold4may also be composed of the plastic material as in the case of the last1so that the forming mold4after being used can be dissolved and recycled for a forming mold4for forming a last1having a different shape.

The last1can be formed by combining together a plurality of masses composed of a plastic material and each smaller than the last1, such as beads5and6shown inFIGS. 6 to 9. The last1shown inFIG. 6is constituted by a plurality of spherical beads5. The plurality of beads5are composed of, for example, polyvinyl alcohol. Water is sprayed to the plurality of beads5arranged into the shape of the last1by, for example, placing the beads5in a mold to allow each adjacent beads5abutting each other to adhere to each other. This adhesion allows the last1to be formed. The last1after being used can be molten by adding water thereto or heating.

The last1shown inFIG. 7andFIG. 8is constituted by a plurality of cylindrical beads6. The plurality of beads6arranged into the shape of the last1by, for example, placing the beads6in a mold are heated to allow each adjacent beads6abutting each other to adhere to each other. This adhesion allows the last1to be formed. The last1after being used can be molten by heat. The cylindrical beads6can be arranged with their axial direction oriented in the vertical direction, as shown inFIG. 7, or with their axial direction oriented in the horizontal direction, as shown inFIG. 8. Further, as shown inFIG. 9, the configuration can be such that a hind portion of the last1is constituted by an integrated portion7composed of the plastic material layered by 3D printing, as in the aforementioned embodiment, and the remaining portion is formed of an aggregate of the plurality of beads6. Although not shown, only the hind portion of the last1may be formed of an aggregate of the plurality of beads6.

The last1may be formed to entirely conform to the shape of the user's foot F, but may be formed to have a specific portion having a desired dimension inconsistent with the shape of the user's foot F for design or functional reasons.

The method for producing the shoe upper2is not limited to the aforementioned embodiment in which the fiber sheet including heat-shrinkable yarns are heat-shrunk, but various methods such as: knitting yarns to form fabric surrounding the last1; or layering a material using a 3D printer can be employed.

The last, the method for producing the last, and the method for producing the shoe upper, of this embodiment are as described above, but the present invention is not limited to the aforementioned embodiment, and the design can be appropriately modified within the scope intended by the present invention. The operational advantages of the present invention are also not limited to the foregoing embodiments. The embodiments disclosed herein should be construed in all respects as illustrative but not limiting. The scope of the present invention is not indicated by the foregoing description but by the scope of the claims Further, the scope of the present invention is intended to include all the modifications equivalent in the sense and the scope of the claims.