JP7751865B1 - Shoe manufacturing method - Google Patents

Abstract

To provide a shoe manufacturing method and auxiliary mold for manufacturing shoes that can be easily put on without using a shoehorn or the like and that can reduce foot fatigue.
[Solution] The shoe includes an upper (12) that defines an internal space for the shoe and a reinforcing structure (14). The upper (12) has a heel portion (20) and a heel guide portion (22) that extends diagonally upward and rearward from the upper end (20a) of the heel portion (20) and defines a guide surface that guides the user's heel into the internal space for the shoe. The reinforcing structure (14) has a plate-shaped first core (38) that is provided along the inner surface of the heel portion (20) and a plate-shaped second core (40) that is provided independently of the first core (38) and along the guide surface of the heel guide portion (22). When manufacturing the shoe, the first core (38) and second core (40) made of thermoplastic resin are attached to the upper (12), and then their shapes are deformed and maintained using a wooden mold (52) and auxiliary molds (54, 64). Next, the first core (38) and second core (40) are heated to soften them, and then cooled.
[Selected Figure] Figure 6

Description

The present invention relates to a method for manufacturing shoes that can be easily put on without using a shoehorn or the like.

An example of a conventional shoe that can be easily put on without using a shoehorn or similar tool is disclosed in Patent Document 1 below. This shoe (shoe with a shoehorn function) has a heel section that covers the area around the heel of the foot, and a heel guide section that extends diagonally upward and rearward from the top end of the heel section. The heel section and heel guide section contain plate-shaped cores to reinforce them. The lower core contained within the heel section and the upper core contained within the heel guide section are integrally formed from synthetic resin.

The shoe disclosed in Patent Document 1 allows the user's heel to slide along the heel guide, making it easy for the user to put on the shoe. However, because the lower core contained within the heel portion and the upper core contained within the heel guide portion are formed as a continuous, integrated unit, the upper part of the heel portion is hard, which creates the problem of the user's feet easily becoming tired when wearing the shoe.

In other words, when a user walks downhill, the ankle tilts backward, causing it to hit the hard part at the top of the heel. On the other hand, when a user walks uphill, the foot slides downward within the shoe, causing the ankle to hit the hard part at the top of the heel. In either case, the user's feet easily become tired.

Utility Model Registration No. 3195071

An object of the present invention is to provide a method for manufacturing shoes that can be easily put on without using a shoehorn or the like and that can reduce foot fatigue.

To achieve the above object, the method for manufacturing a shoe according to the present invention is characterized by the following features: an upper preparation step for preparing an upper having a heel portion curved to fit the heel of a user, and a heel guide portion extending obliquely upward and rearward from the upper end of the heel portion and constituting a guide surface for guiding the heel of the user into the shoe interior; a core attachment step for attaching a plate-shaped first core material made of a thermoplastic resin to the inner surface of the heel portion and attaching a plate-shaped second core material made of a thermoplastic resin to the guide surface of the heel guide portion; and a shoe manufacturing method for manufacturing the shoe having the first and second core materials attached thereto. The method comprises a wooden last attachment step of attaching a wooden last to the upper and aligning the heel portion and the first core material to the wooden last; an auxiliary mold attachment step of inserting a first auxiliary mold between the wooden last and the heel guide portion and aligning the heel guide portion and the second core material to the first auxiliary mold; a heating step of heating and softening the first core material and the second core material whose shapes are maintained by the wooden last and the first auxiliary mold; and a cooling step of cooling and hardening the first core material and the second core material softened in the heating step while their shapes are maintained by the wooden last and the first auxiliary mold.

In this shoe manufacturing method, the first and second cores are softened in a heating process, allowing them to be deformed into a shape that conforms to the wooden last and first auxiliary mold. This eliminates the need to pre-form the first and second cores into a special shape tailored to the shoe specifications, reducing manufacturing costs. Furthermore, because the first and second cores are independent of each other, the first core can be shared with other shoes with different heel guide shapes, reducing manufacturing costs.

Another feature of the shoe manufacturing method of the present invention is that, in the core attachment process, the first core and the second core are positioned so that they do not overlap each other.

With this shoe manufacturing method, the first core and the second core do not overlap each other, so the upper part of the heel does not become stiff, and the user's feet do not get tired easily when wearing the shoes.

Another feature of the shoe manufacturing method of the present invention is that it includes a core preparation step in which the first core and the second core are prepared by cutting them from a single thermoplastic resin sheet.

In this shoe manufacturing method, the first core and second core are cut from a common thermoplastic resin sheet, reducing manufacturing costs. Furthermore, although the first core attached to the inner surface of the heel and the second core attached to the upper surface of the heel guide are different sizes, by appropriately determining the cutting patterns for the first and second cores in the thermoplastic resin sheet, the first and second cores can be cut without waste.

Another feature of the shoe manufacturing method of the present invention is that the core attachment step includes a step of adhering the second core to the guide surface with a hot melt adhesive.

This shoe manufacturing method allows the second core to be temporarily fixed to the guide surface of the heel guide section with hot melt adhesive, preventing the second core from shifting position during subsequent auxiliary mold attachment processes. Furthermore, the hot melt adhesive melts and spreads over a wide area during the heating process, ensuring reliable bonding of the second core to the heel guide section and reinforcing the second core.

Another feature of the shoe manufacturing method of the present invention is that the upper has a sheet-like tongue that covers the instep of the user's foot, the core attachment process includes attaching a plate-like third core formed of a thermoplastic resin to the underside of the tongue, the auxiliary mold attachment process includes inserting a second auxiliary mold between the wooden last and the tongue and aligning the tongue and the third core with the second auxiliary mold, the heating process includes heating and softening the third core whose shape is maintained by the wooden last and the second auxiliary mold, and the cooling process includes cooling and hardening the third core softened in the heating process while its shape is maintained by the wooden last and the second auxiliary mold.

In this shoe manufacturing method, the third core material is softened in a heating process and can be deformed to a shape that conforms to the second auxiliary mold. This eliminates the need to pre-form the third core material into a special shape that matches the shoe specifications, reducing manufacturing costs.

FIG. 1 is a perspective view showing the configuration of a shoe. 1A and 1B are diagrams showing the configuration of a shoe, in which (A) is a plan view and (B) is a front view. (A-1) is a front view showing the configuration of the first core material before suturing, (A-2) is a front view showing the configuration of the first core material after suturing, (B) is a front view showing the configuration of the second core material, and (C) is a front view showing the configuration of the third core material. FIG. 2 is a front view showing a cutting pattern for a core material defined in a single thermoplastic resin sheet. FIG. 2 is a flow chart showing a method for manufacturing shoes according to an embodiment. (A) is a front view showing the bag body, (B) is a front view showing the state in which the wooden mold is attached to the upper, and (C) is a front view showing the state in which the first auxiliary mold is inserted between the wooden mold and the heel guide part and the second auxiliary mold is inserted between the wooden mold and the tongue part. 1A to 1C are diagrams showing the configuration of a first auxiliary mold, in which (A) is a perspective view, (B) is a front view, and (C) is a right side view. 10A to 10C are diagrams showing the configuration of a second auxiliary mold, in which (A) is a perspective view, (B) is a front view, and (C) is a left side view. FIG. 2 is a front view showing the configuration of a heating device for performing a heating step.

Hereinafter, a shoe manufacturing method according to an embodiment of the present invention will be described with reference to the drawings.

(Shoe configuration)
FIG. 1 is a perspective view showing the configuration of shoe 10. FIG. 2 shows the configuration of shoe 10, with FIG. 2(A) being a plan view and FIG. 2(B) being a front view. FIG. 3(A-1) is a front view showing the configuration of first core 38 before sewing, FIG. 3(A-2) is a front view showing the configuration of first core 38 after sewing, FIG. 3(B) is a front view showing the configuration of second core 40, and FIG. 3(C) is a front view showing the configuration of third core 42. FIG. 4 is a front view showing the cutout pattern of the core set in a single thermoplastic resin sheet 46.

The shoe 10 shown in Figure 1 comprises an upper 12 that defines the interior space S, a reinforcing structure 14 that reinforces the upper 12, a lining 16 that covers the inner surface of the upper 12, and a sole 18. Note that although the shoe 10 shown in Figure 1 is a lace-up shoe, the laces are omitted from the drawing.

As shown in FIG. 2(A), the upper 12 has a heel portion 20 curved to fit the user's heel, a heel guide portion 22 that forms a guide surface 22a that guides the user's heel into the shoe interior space S, an inner portion 24 that covers the inside of the user's foot, an outer portion 26 that covers the outside of the user's foot, a toe portion 28 that covers the user's toes, and a tongue portion 30 that covers the user's instep. Because the guide surface 22a is covered by the lining 16, when the user puts on the shoe 10, the user's heel comes into contact with the guide surface 22a via the lining 16.

The upper 12 shown in Figures 2(A) and (B) is constructed by sewing together multiple sheet-like components such as leather. As shown in Figure 2(A), the center of the upper 12 is formed with an opening 32 for inserting the user's foot into the shoe interior space S, and a cutout 34 that is continuous with the opening 32. On both sides of the cutout 34 in the center of the upper 12, a plurality of lace holes 36 are formed for threading shoelaces (not shown).

As shown in Figure 2(A), the heel portion 20 is curved so that it bulges backward in a U-shape when viewed from above, and the heel guide portion 22 extends diagonally upward and backward from the upper end 20a (Figure 2(B)) of the heel portion 20, and is curved so that it bulges backward in a U-shape. The sheet-like components that make up the heel portion 20 and the sheet-like components that make up the heel guide portion 22 are prepared independently and sewn together.

Heel guide 22 extends diagonally upward and rearward, so the upper edge of heel guide 22 is also the rear edge, and the lower edge of heel guide 22 is also the front edge. Furthermore, heel guide 22 is curved to bulge in a U-shape, so guide surface 22a is also the inner surface of heel guide 22.

The inclination angle θ of the center of the heel guide 22 (guide surface 22a) in the left-right direction relative to the vertical line L shown in Figure 2 (B) is set to 15 degrees. Note that this inclination angle θ is not limited to 15 degrees and can be changed as appropriate taking into consideration factors such as heel slipperiness, but it is desirable for it to be within the range of 10 to 45 degrees.

The tongue portion 30 shown in Figures 2(A) and (B) is formed in a rectangular shape (not shown) so as to close the cutout portion 34. In other words, the tongue portion 30 is composed of a rectangular sheet-like part. One longitudinal end of the tongue portion 30, i.e., the front end, is sewn to the toe portion 28 of the upper 12.

As shown in Figure 2 (B), the tongue portion 30 is inclined so that its rear end is higher than its front end. The tongue portion 30 is also curved so that its central portion in the left-right direction bulges upward in a U-shape. At least the region of the tongue portion 30 extending 10 to 15 mm from its rear end is inclined significantly diagonally upward and rearward. Therefore, when a user puts on the shoe 10, the user's toes are less likely to get caught on the rear end of the tongue portion 30.

The material for the upper 12 is not particularly limited, but it is desirable for it to have the property of softening when heated and hardening when cooled; specifically, natural leather or thermoplastic synthetic leather is desirable.

The reinforcing structure 14 shown in FIG. 1 comprises a plate-shaped first core material 38 provided between the heel portion 20 and the lining 16 along the inner surface of the heel portion 20, a plate-shaped second core material 40 provided between the heel guide portion 22 and the lining 16 along the guide surface 22a of the heel guide portion 22, and a plate-shaped third core material 42 provided between the tongue portion 30 and the lining 16 along the underside of the rear end of the tongue portion 30.

The first core 38 is a so-called "moon-shaped core" and is curved to bulge backward in a U-shape in a plan view, so as to fit along the inner surface of the heel section 20. The second core 40 is curved to bulge diagonally downward and rearward in a U-shape, so as to fit along the guide surface 22a of the heel guide section 22. The third core 42 is curved so that the center portion in the left-right direction bulges upward in a U-shape, so as to fit along the underside of the rear end of the tongue section 30, at least in a region 10 to 15 mm from the rear end.

The first core 38, second core 40, and third core 42 are cut into flat plates from the thermoplastic resin sheet 46 shown in Figure 4, heated and deformed in the heating step S7 (Figure 5) described below, and then cooled in the cooling step S9 (Figure 5) to fix their shapes. Therefore, the heel section 20, heel guide section 22, and tongue section 30 shown in Figure 1 are not only reinforced by the first core 38, second core 40, and third core 42, but also retain their shapes.

As shown in Figure 3 (A-1), the flat first core material 38 is formed to cover almost the entire heel portion 20 (Figure 1). In other words, the upper edge 38a of the first core material 38 is curved so as to descend from the left-right center toward both ends, along the upper edge of the heel portion 20. The lower edge 38b of the first core material 38 is linearly formed so as to gradually ascend from the left-right center toward both ends, along the lower edge of the heel portion 20. An inverted V-shaped notch 38c is formed in the lower part of the left-right center of the first core material 38.

As shown in Figure 3 (A-2), the left and right portions of the first core 38 that face each other across the cutout 38c are sewn together with thread 44, giving the first core 38 a three-dimensional shape with a bulging center. Therefore, in the core attachment process S1c (Figure 5) described below, it is easy to align the entire first core 38 with the inner surface of the heel portion 20.

In addition, the top, left, and right ends of the first core 38 (portions outside the dashed dotted line) are formed so that their thickness gradually decreases toward these edges. Therefore, in the core attachment process S1c (Figure 5) described below, it is particularly easy to align the thin top, left, and right ends of the first core 38 with the inner surface of the heel portion 20.

As shown in Figure 3 (B), the flat second core material 40 is formed to correspond to almost the entire heel guide 22 (Figure 1). In other words, the upper edge (rear edge) 40a of the second core material 40 is curved so as to descend from the center toward both ends in the left-right direction, so as to follow the upper edge (rear edge) of the heel guide 22. The lower edge (front edge) 40b of the second core material 40 is linearly formed so as to descend gradually from the center toward both ends in the left-right direction, so as to follow the lower edge (front edge) of the heel guide 22.

In addition, the top, left, and right ends of the second core material 40 (the portions outside the dashed dotted lines) are formed so that their thickness gradually decreases toward these edges. Therefore, in the core material attachment process S1c (Figure 5) described below, it is particularly easy to align the top, left, and right ends of the thinly formed second core material 40 with the guide surface 22a.

As shown in Figure 3 (C), the flat third core material 42 is rectangular so as to cover almost the entire left-right area of the rear end of the tongue section 30 (Figure 1). In other words, the left-right (longitudinal) length of the third core material 42 is set slightly shorter than the left-right length of the rear end of the tongue section 30, and the front-to-rear (transverse) length of the third core material 42 is set sufficiently shorter than the left-to-right length.

The first core 38 shown in Figure 3 (A-1), the second core 40 shown in Figure 3 (B), and the third core 42 shown in Figure 3 (C) are formed by cutting the thermoplastic resin sheet 46 shown in Figure 4, and are adhered to the corresponding parts of the upper 12 (Figure 1) using a hot melt adhesive. The type of thermoplastic resin sheet 46 is not particularly limited, but the shoe 10 uses a sheet made of polyester nonwoven fabric impregnated with styrene butadiene (SBR latex).

(Method for manufacturing shoes according to the embodiment)
FIG. 5 is a flow diagram showing a shoe manufacturing method according to an embodiment. FIG. 6(A) is a front view of the pouch 48, FIG. 6(B) is a front view showing the shoe tree 52 attached to the upper 12, and FIG. 6(C) is a front view showing the first auxiliary die 54 inserted between the shoe tree 52 and the heel guide 22 and the second auxiliary die 64 inserted between the shoe tree 52 and the tongue 30. FIG. 7 shows the configuration of the first auxiliary die 54, with FIG. 7(A) being a perspective view, FIG. 7(B) being a front view, and FIG. 7(C) being a right side view. FIG. 8 shows the configuration of the second auxiliary die 64, with FIG. 8(A) being a perspective view, FIG. 8(B) being a front view, and FIG. 8(C) being a left side view. FIG. 9 is a front view showing the configuration of a heating device 74 used to perform the heating step S7.

In the shoe manufacturing method, the manufacturer performs the bag manufacturing process S1, last attachment process S3, auxiliary mold attachment process S5, heating process S7, cooling process S9, and sole attachment process S11 shown in Figure 5 in this order. In other words, the shoe manufacturing method includes the bag manufacturing process S1, last attachment process S3, auxiliary mold attachment process S5, heating process S7, cooling process S9, and sole attachment process S11.

The pouch manufacturing process S1 shown in Figure 5 is a process for manufacturing the pouch 48 shown in Figure 6 (A). The pouch 48 is the portion of the shoe 10 shown in Figure 1 excluding the sole 18, and is constructed in a pouch shape by sewing a flexible false sole 50 to the bottom of the upper 12.

As shown in Figure 5, in the bag manufacturing process S1, the manufacturer performs the upper preparation process S1a, the core preparation process S1b, the core attachment process S1c, the lining attachment process S1d, and the temporary sole attachment process S1e in this order. In other words, the bag manufacturing process S1 includes the upper preparation process S1a, the core preparation process S1b, the core attachment process S1c, the lining attachment process S1d, and the temporary sole attachment process S1e.

In the upper preparation process S1a shown in Figure 5, the manufacturer prepares the upper 12 of the bag body 48 shown in Figure 6 (A) by sewing together multiple sheet-like components such as leather. As described above, the upper 12 has a heel portion 20 that is curved to fit the user's heel, and a heel guide portion 22 that extends diagonally upward and rearward from the upper end 20a of the heel portion 20 and forms a guide surface 22a that guides the user's heel into the in-shoe space S.

In the core material preparation process S1b shown in Figure 5, the manufacturer prepares the first core material 38 shown in Figure 3 (A-2), the second core material 40 shown in Figure 3 (B), and the third core material 42 shown in Figure 3 (C). In other words, the manufacturer sets cutting patterns for the first core material 38, second core material 40, and third core material 42 on a single thermoplastic resin sheet 46 shown in Figure 4 without waste, and then cuts out the first core material 38, second core material 40, and third core material 42 according to these patterns. Furthermore, as shown in Figure 3 (A-2), the cutouts 38c in the first core material 38 are closed with thread 44 to give the first core material 38 a three-dimensional shape.

In the core attachment step S1c shown in Figure 5, the manufacturer attaches the first core 38 to the inner surface of the heel portion 20 and the second core 40 to the guide surface 22a of the heel guide portion 22. The manufacturer also attaches the third core 42 to the underside of the rear end of the tongue portion 30. As described above, the first core 38, second core 40, and third core 42 are made of thermoplastic resin and are flexible plates. This allows the manufacturer to easily align them with the inner surface of the heel portion 20, the guide surface 22a, and the underside of the rear end of the tongue portion 30.

The specific method for attaching the first core 38, second core 40, and third core 42 to the upper 12 is by bonding them using a hot melt adhesive. In other words, the core attachment process S1c includes the steps of bonding the first core 38 to the inner surface of the heel portion 20 with a hot melt adhesive, bonding the second core 40 to the guide surface 22a with a hot melt adhesive, and bonding the third core 42 to the underside of the rear end of the tongue portion 30 with a hot melt adhesive. Note that this bonding is for temporary fixation; permanent fixation will be performed in the subsequent heating process S7 and cooling process S9.

In the lining attachment process S1d shown in Figure 5, the manufacturer sews the lining 16 (Figure 1) to the inner surface of the upper 12 shown in Figure 6 (A).

In the temporary sole attachment step S1e shown in Figure 5, the manufacturer sews a flexible cloth- or sheet-like temporary sole 50 to the bottom of the upper 12 shown in Figure 6 (A). The temporary sole 50 will be heated in the subsequent heating step S7, so it must have heat resistance at least as great as that of the upper 12.

In the last-fitting step S3 shown in Figure 5, the manufacturer attaches the last 52 shown in Figure 6 (B) to the upper 12 to which the first core 38, second core 40, and third core 42 have been attached. The upper 12 and first core 38 are then deformed to fit the last 52, and this shape is maintained by the last 52.

In the auxiliary mold attachment step S5 shown in Figure 5, the manufacturer attaches the first auxiliary mold 54 shown in Figure 6 (C) to the rear of the upper end of the wooden mold 52, i.e., the first attachment portion 52a, and inserts the first auxiliary mold 54 between the wooden mold 52 and the heel guide portion 22. This causes the heel guide portion 22 and the second core material 40 to deform to fit the first auxiliary mold 54, and this shape is maintained by the first auxiliary mold 54.

As shown in Figures 7(A), (B), and (C), the first auxiliary mold 54 includes a rectangular plate-shaped left wall 56 covering the left surface of the first attachment portion 52a shown in Figure 6(C), a rectangular plate-shaped right wall 58 covering the right surface of the first attachment portion 52a, a rear wall 60 covering the rear surface of the first attachment portion 52a, and an upper wall 62 covering the top surface of the first attachment portion 52a. The front surface 60a of the rear wall 60 shown in Figure 7(C) is formed to fit along the rear surface of the first attachment portion 52a, and the rear surface 60b of the rear wall 60 shown in Figure 7(B) is formed at an angle relative to the front surface 60a to fit along the guide surface 22a of the heel guide portion 22.

The left wall 56, right wall 58, rear wall 60, and top wall 62 are integrally formed from synthetic resin to provide flexibility. The left wall 56, right wall 58, and rear wall 60 are all formed so that their cross-sectional shape is U-shaped and opens forward, and the top wall 62 is also U-shaped and opens forward in plan view. Therefore, the first auxiliary mold 54 can elastically open left and right, and when the first auxiliary mold 54 is attached to the first attachment portion 52a, it is difficult for the first auxiliary mold 54 to detach from the first attachment portion 52a.

The lower ends of the left wall 56, right wall 58, and rear wall 60 are formed so that their thickness gradually decreases toward the bottom edge. This reduces the steps that occur between the outer surface of the wooden mold 52 and the outer surfaces of the left wall 56, right wall 58, and rear wall 60, thereby enhancing the sense of unity between the wooden mold 52 and the first auxiliary mold 54.

Furthermore, in the auxiliary mold attachment step S5 shown in Figure 5, the manufacturer attaches the second auxiliary mold 64 shown in Figure 6 (C) to the inclined portion of the wooden mold 52, i.e., the second attachment portion 52b, and inserts the second auxiliary mold 64 between the wooden mold 52 and the tongue portion 30. This causes the tongue portion 30 and the third core material 42 to deform to fit the second auxiliary mold 64, and this shape is maintained by the second auxiliary mold 64.

As shown in Figures 8(A), (B), and (C), the second auxiliary mold 64 includes a triangular plate-shaped left wall 66 that covers the left surface of the second attachment portion 52b shown in Figure 6(C), a triangular plate-shaped right wall 68 that covers the right surface of the second attachment portion 52b, and an upper wall 70 that covers the upper surface of the second attachment portion 52b. The left wall 66, right wall 68, and upper wall 70 are integrally formed from synthetic resin to be flexible. The lower edges of the left wall 66 and right wall 68 are curved so that they bulge downward when viewed from the front (Figure 8(B)).

The lower surface 70a of the upper wall 70 shown in Figure 8(C) is formed to fit along the upper surface of the second mounting portion 52b. The upper surface 70b of the upper wall 70 shown in Figure 8(B) is inclined relative to the lower surface 70a so as to fit along the lower surface of the tongue portion 30, and is gently curved so as to bulge downward.

In the auxiliary mold attachment step S5, it is not necessary to align the entire upper surface 70b of the upper wall 70 with the underside of the tongue portion 30; the upper surface 70b may be aligned only with the portion of the tongue portion 30 whose shape is to be maintained. In this embodiment, the upper surface 70b is aligned with at least an area of the tongue portion 30 extending 10 to 15 mm from the rear end. The position of the second auxiliary mold 64 relative to the tongue portion 30 is then fixed with a fixing member 72 (Figure 9) such as an annular rubber material.

In the heating step S7 shown in FIG. 5, the manufacturer heats the bag body 48 using a heating device 74 shown in FIG. 9 to heat the first core material 38, second core material 40, and third core material 42 incorporated into the bag body 48. As shown in FIG. 9, the heating device 74 includes a device main body 76 that forms a heating chamber Q, a heater 78 for heating that is disposed in the heating chamber Q, and a control unit 80 that controls the heating temperature and operating time (i.e., heating time) of the heater 78.

When the bag body 48 is heated by the heating device 74, the first core 38, whose shape is maintained by the wooden mold 52, softens and adheres to the inner surface of the heel portion 20, and the hot melt adhesive is melted by heat, thereby adhering the first core 38 to the heel portion 20. The second core 40, whose shape is maintained by the first auxiliary mold 54, softens and adheres to the guide surface 22a of the heel guide portion 22, and the hot melt adhesive is melted by heat, thereby adhering the second core 40 to the heel guide portion 22. The third core 42, whose shape is maintained by the second auxiliary mold 64, softens and adheres to the underside of the rear end of the tongue portion 30, and the hot melt adhesive is melted by heat, thereby adhering the third core 42 to the tongue portion 30. The heating temperature and operating time of the heater 78 are not particularly limited, but in this embodiment, the heating temperature is set to a range of 120 to 140°C, and the operating time is set to a range of 30 to 40 minutes.

In the cooling step S9 shown in Figure 5, the manufacturer cools and hardens the first core material 38, second core material 40, and third core material 42 that were heated and softened in the heating step S7. Note that no special cooling equipment is required to cool the first core material 38, second core material 40, and third core material 42; they can be cooled naturally in the factory environment.

In the sole attachment process S11 shown in Figure 5, the manufacturer glues and sews the sole 18 to the bottom of the upper 12.

(Effects of the embodiment)
The shoe 10 manufactured by the shoe manufacturing method of the embodiment can achieve the following effects due to the above configuration. As shown in Figure 1, the heel portion 20 is reinforced by the first core 38, and the heel guide portion 22 is reinforced by the second core 40. Therefore, even when the heel guide portion 22 is stepped on by the user's foot, the heel portion 20 and the heel guide portion 22 are less likely to deform. This allows the user to easily put on the shoe without using a shoehorn or the like.

As shown in Figure 2 (B), the second core 40 is provided independently of the first core 38, ensuring flexibility of the upper 12 between the first core 38 and the second core 40. In other words, flexibility of the upper part of the heel 20 is ensured. Therefore, when going uphill or downhill, the user's foot can be prevented from hitting the upper part of the heel 20 hard, reducing fatigue in the user's feet.

The heel guide 22 and second core 40 are curved to bulge diagonally downward and rearward in a U-shape, so that even when the rear end of the heel guide 22 is stepped on by the user's foot, the heel guide 22 and second core 40 are less likely to bend, allowing the user to easily put on their shoes without using a shoehorn or other tool.

As shown in FIG. 3 (A-2), the upper end of the first core 38 is formed so that its thickness gradually decreases toward the upper edge 38a, thereby preventing a step from occurring between the inner surface of the heel portion 20 (FIG. 1) and the inner surface of the upper end of the first core 38. Furthermore, as shown in FIG. 3 (B), the upper end (rear end) of the second core 40 is formed so that its thickness gradually decreases toward the upper edge (rear edge) 40a, thereby preventing a step from occurring between the guide surface 22a and the inner surface of the second core 40. Therefore, the user's heel will not get caught on these steps, allowing the user to wear the shoe 10 without any discomfort.

As shown in FIG. 1, the tongue portion 30 and the third core material 42 are curved so that their left-right central portions bulge upward. This makes the tongue portion 30 less likely to deform even when pressed with the toes, allowing the user to easily put on the shoe 10 without using their hands. Furthermore, at least the area 10 to 15 mm from the rear end of each of the tongue portion 30 and the third core material 42 is formed with a large upward and rearward slope. This, combined with the curved shape, makes it less likely that the user's toes will get caught on the rear end of the tongue portion 30 when putting on the shoe 10.

The shoe manufacturing method of this embodiment, with its above-described configuration, can achieve the following effects. Specifically, the first core 38, second core 40, and third core 42 are softened in the heating step S7 (Figure 5) and can be deformed to a shape that conforms to the wooden last 52, first auxiliary mold 54, and second auxiliary mold 64. This eliminates the need to pre-form these cores into a special shape that matches the specifications of the shoe 10, thereby reducing the manufacturing cost of the shoe 10. Furthermore, because the first core 38, second core 40, and third core 42 are independent of each other, the first core 38 can be shared even when manufacturing other shoes 10 with differently shaped heel guide sections 22 or tongue sections 30, thereby reducing the manufacturing cost of the shoe 10.

In the core material preparation process S1b shown in Figure 5, the first core material 38, second core material 40, and third core material 42 are cut from a common thermoplastic resin sheet 46, thereby reducing manufacturing costs. Furthermore, although the first core material 38, second core material 40, and third core material 42 are different sizes, by appropriately defining the cutting pattern in the thermoplastic resin sheet 46, they can be cut out without waste.

In the core attachment process S1c shown in Figure 5, the first core 38, second core 40, and third core 42 are temporarily fixed to the inner surface of the heel section 20, the guide surface 22a of the heel guide section 22, and the underside of the rear end of the tongue section 30 with hot melt adhesive, preventing these from shifting position during the subsequent auxiliary attachment process S5, etc. Furthermore, because the hot melt adhesive melts and spreads over a wide area during the heating process S7, a high adhesive effect can be achieved while minimizing the amount of adhesive used.

In the auxiliary mold attachment step S5 shown in Figure 5, the first auxiliary mold 54 can be easily attached to the wooden mold 52 by simply placing the entire left wall 56, right wall 58, rear wall 60, and top wall 62 of the first auxiliary mold 54 (Figure 7) over the first attachment portion 52a of the wooden mold 52 (Figure 6(C)). Furthermore, by preparing multiple first auxiliary molds 54 with different inclination angles and shapes of the front surface 60a and rear surface 60b of the rear wall 60 (Figure 7(B)), it is possible to accommodate multiple heel guide portions 22 with different inclination angles θ (Figure 2(B)) and shapes.

(Modification)
It should be noted that the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the scope of the present invention. That is, in the above-described shoe 10, the cutout portion 34 formed in the upper portion of the upper 12 shown in FIG. 2(A) is closed by a shoelace (not shown), but the cutout portion 34 may also be closed by a rubber belt or the like.

In the above-described shoe 10, the upper, left, and right ends (portions outside the dashed dotted line) of the first core 38 shown in Figure 3 (A-2) are formed so that their thickness gradually decreases toward these edges. In addition, the lower end of the first core 38 may be formed so that its thickness gradually decreases toward the lower edge 38b. Alternatively, only the upper end of the first core 38 may be formed so that its thickness gradually decreases toward the upper edge 38a. In other words, at least the upper end of the first core 38 may be formed so that its thickness gradually decreases toward the upper edge 38a.

In the shoe 10 described above, the upper, left, and right ends (portions outside the dashed dotted line) of the second core 40 shown in Figure 3 (B) are formed so that their thickness gradually decreases toward these edges. In addition, the lower end of the second core 40 may be formed so that its thickness gradually decreases toward the lower edge 40b. Alternatively, only the upper end of the second core 40 may be formed so that its thickness gradually decreases toward the upper edge 40a. In other words, at least the upper end of the second core 40 may be formed so that its thickness gradually decreases toward the upper edge 40a.

In the shoe manufacturing method of the above embodiment, in the core attachment step S1c shown in Figure 5, the first core 38, second core 40, and third core 42 are temporarily fixed to the corresponding parts of the upper 12 with hot melt adhesive. However, instead of hot melt adhesive, other adhesives or double-sided adhesive tape may be used for temporary fixation.

In the shoe manufacturing method of the above embodiment, the lining attachment step S1d is performed after the core attachment step S1c shown in Figure 5. However, the core attachment step S1c may be performed after the lining attachment step S1d. In this case, in the core attachment step S1c, the first core 38, second core 40, and third core 42 may be inserted through insertion openings provided between the upper 12 and the lining 16, and then adhered to the corresponding parts of the upper 12 with hot melt adhesive.

In the shoe manufacturing method of the above embodiment, the last attachment process S3 is performed after the temporary sole attachment process S1e shown in Figure 5. However, if a method of suspending the upper 12 onto the last 52 is used in the last attachment process S3, the temporary sole attachment process S1e may be omitted.

In the shoe manufacturing method of the above embodiment, the sole attachment process S11 is performed after the heating process S7 and cooling process S9 shown in Figure 5. However, if the sole 18 shown in Figure 1 has heat resistance at least as good as that of the upper 12, the sole attachment process S11 may be performed before the heating process S7 and cooling process S9.

L...vertical line, Q...heating chamber, S...inner space of shoe, 10...shoe, 12...upper, 14...reinforcing structure, 16...lining, 18...sole, 20...heel portion, 20a...upper end, 22...heel guide portion, 22a...guide surface, 24...medial portion, 26...lateral portion, 28...toe portion, 30...tongue portion, 32...opening, 34...cutout portion, 36...lace holes, 38...first core material, 38a...upper edge, 38b...lower edge, 38c...cutout, 40...second core material, 40a...upper edge, 40b...lower edge, 4 2...third core material, 44...thread, 46...thermoplastic resin sheet, 48...bag body, 50...false bottom, 52...wooden mold, 52a...first attachment portion, 52b...second attachment portion, 54...first auxiliary mold, 56...left wall, 58...right wall, 60...rear wall, 60a...front surface, 60b...rear surface, 62...top wall, 64...second auxiliary mold, 66...left wall, 68...right wall, 70...top wall, 70a...bottom surface, 70b...top surface, 72...fixing member, 74...heating device, 76...device main body, 78...heater, 80...control unit.

Claims (5)

an upper preparation process for preparing an upper having a heel portion curved to fit the heel of a user, and a heel guide portion extending obliquely upward and rearward from the upper end of the heel portion to form a guide surface for guiding the heel of the user into a shoe interior space;
a core attachment step of attaching a plate-shaped first core made of a thermoplastic resin to the inner surface of the heel portion and attaching a plate-shaped second core made of a thermoplastic resin to the guide surface of the heel guide portion;
a last-fitting step of fitting a last to the upper to which the first core and the second core are attached and aligning the heel portion and the first core with the last;
an auxiliary mold attachment step of inserting a first auxiliary mold between the wooden mold and the heel guide portion and aligning the heel guide portion and the second core material with the first auxiliary mold;
a heating step of heating and softening the first core material and the second core material whose shapes are maintained by the wooden mold and the first auxiliary mold;
a cooling step of cooling and hardening the first core material and the second core material softened in the heating step while their shapes are maintained by the wooden mold and the first auxiliary mold. The shoe manufacturing method described in claim 1, wherein, in the core attachment process, the first core and the second core are positioned so as not to overlap each other. The shoe manufacturing method described in claim 1, further comprising a core preparation step in which the first core and the second core are prepared by cutting them from a single thermoplastic resin sheet. The shoe manufacturing method according to any one of claims 1 to 3, wherein the core attachment step includes a step of adhering the second core to the guide surface with a hot melt adhesive. The upper has a sheet-like tongue portion that covers the instep of the user's foot,
the core material attaching step includes a step of attaching a plate-shaped third core material formed of a thermoplastic resin to a lower surface of the tongue portion,
The auxiliary mold attaching step includes a step of inserting a second auxiliary mold between the wooden mold and the tongue portion and aligning the tongue portion and the third core material with the second auxiliary mold,
the heating step includes a step of heating and softening the third core material whose shape is maintained by the wooden mold and the second auxiliary mold,
4. The shoe manufacturing method according to claim 1, wherein the cooling step includes a step of cooling and hardening the third core material softened in the heating step while the shape of the third core material is maintained by the wooden mold and the second auxiliary mold.