JP5052912B2 - Shoes manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a shoe with a built-in tip by injection molding.

Conventionally, a manufacturing method of a safety boot with a toe core in which a tip is attached to a last mold as a core mold, and a sock-like lining cloth is put on the last mold on which the tip is attached is known. (Patent Document 1).
JP 2003-334870 A

  In the manufacturing method of the safety boot described in Patent Document 1, a backing cloth is put on the last mold on which the tip is attached in order to prevent the tip attached on the last mold from falling off. Therefore, on the inner side of the completed shoe, the portion without the tip is exposed by the backing cloth, but the portion having the tip has no backing cloth. That is, in the safety boot according to the manufacturing method, since there is no backing cloth at the toe portion, the injection-molded rubber or vinyl ground comes into direct contact with the user's foot. This gives the user an unpleasant comfort such as being easily stuffy due to sweat and slipping in wet shoes.

  The present invention relates to a method for manufacturing a shoe in which a backing cloth is exposed throughout the shoe including the toe portion, and the tip core attached to the core die is fixed to the core die at the time of manufacture without dropping. Etc. to be provided.

In order to solve the above problems, the invention described in claim 1 of the present application is characterized by having the following configuration. That is,
A shoe manufacturing method formed by a core mold that forms the inside of a shoe and a cavity mold that forms the outer shape of the shoe,
Having a toe with a lower bent portion to be attached to the toe part of the core mold,
The toe portion of the core mold to which the tip is attached is provided with an upper projection that protrudes from the upper surface and a bottom projection that protrudes from the bottom surface, forming a gap with the tip,
Preventing the tip from dropping off from the core mold by forming an engaged portion that engages with a bottom protrusion of the core mold on the upper surface of the lower bent portion of the tip;
A gap is formed on the inner side surface of the tip core between the upper side surface and the bottom side surface of the core mold, and the thermoplastic resin is also formed in the gap formed by the tip core and the core mold during injection molding. A method for manufacturing a shoe, characterized in that the shoe is filled.

The invention according to claim 2 of the present application has the following configuration. That is,
The shoe manufacturing method according to claim 1, wherein the tip is formed of a synthetic resin.

In the method for manufacturing a shoe according to the present invention, the tip core attached to the mold is prevented from falling off by fitting the mold with the mold. Therefore, there is an effect that it is not necessary to hit the tip with a die forcibly and attach it to the mold for the purpose of preventing falling off or to cover with a backing cloth after the tip is attached.
Further, the engaging means used for fitting the tip and the mold also acts as a spacer for forming a gap between the mold and the inner surface of the tip, so that the tip is placed inside the shoe after molding. It has the effect that the inner surface of the surface does not appear.
Furthermore, the shoe manufacturing method according to the present invention can attach the tip after the mold is covered with the lining cloth, so that the lining cloth can be disposed on the entire inner surface of the shoe in contact with the foot. There is an effect that comfortable shoes can be provided.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.
1 and 2 are schematic views of an injection molding apparatus 1 to which a shoe manufacturing method according to the present invention is applied. This Embodiment demonstrates the case where the boots 2 are manufactured as an example of the manufacturing method of shoes.
The mold used for the injection molding apparatus 1 is composed of a core mold 3 that forms the inner surface of the boots 2 and a cavity mold that surrounds the core mold 3. The cavity mold is constituted by side molds 4 and 5 divided into two in the left-right direction and a bottom mold 6 mainly forming a shoe sole.

The process of manufacturing the boots 2 will be briefly described. The boots 2 (FIG. 2B) are prepared by injecting a molten thermoplastic resin into a gap (molding space) formed by the core mold 3 and the cavity mold at a high pressure and cooling the thermoplastic resin. The mold is opened to take out boots as a molded product.
As a process, first, before injection of the thermoplastic resin, a sock-shaped backing cloth 7 like a stocking is put on the core mold 3, and the tip core 8 is covered with the core mold 3 while further covering the backing cloth 7. Attach to the toe. The engagement between the tip 8 and the core mold 3 will be described in detail later. The periphery of the core mold 3 to which the backing cloth 7 and the tip 8 are attached is surrounded by the side molds 4, 5 and the bottom mold 6, filled with a thermoplastic resin, and cooled to obtain a boot 2 having a predetermined shape.
FIG. 2A shows a state in which the core mold 3 to which the backing cloth 7 and the tip 8 are attached is surrounded by the side molds 4 and 5. The apparatus shown in FIGS. 1 and 2 (a) is shown in a simplified manner for the sake of explanation, and details such as the shape and the injection port of the thermoplastic resin are omitted.

The tip 8 used in the present embodiment is made of synthetic resin. FIG. 3 is an explanatory view of the tip 8, FIG. 3A is a sectional view of the tip 8 (a sectional view taken along line AA in the rear view shown in FIG. 3B), and FIG. FIG. 3C is a bottom view of the tip 8 corresponding to the cross-sectional view, and FIG. 3D is a skirt of the tip 8 (lower bent portion). It is explanatory drawing of the protrusion provided in the upper surface.
The tip 8 is a so-called resin tip made of a synthetic resin, and is formed as a shell having an opening 9 provided on the foot insertion side and an opening 10 provided on the sole side. The illustrated tip 8 is formed by injection molding of a polycarbonate that does not contain a reinforcing material such as glass fiber, but may be formed of polypropylene (PP) kneaded with glass fiber or the like. In that case, the shape such as the thickness is appropriately changed according to the physical properties such as the strength of the material. As other materials, synthetic resins such as nylon, polybutylene terephthalate, polyoxymethylene, acrylonitrile butadiene styrene (ABS), polyethylene terephthalate (PET), those obtained by adding glass fibers, or the above synthetic resins You may form by what mixed the mineral etc. in this and heightened the intensity | strength, or a polymer alloy.

The thickness of the shell constituting the tip 8 is approximately 2 to 9 mm although it varies depending on the part. In particular, the toe portion is formed to have a thickness of 5 to 9 mm and has high impact resistance and pressure resistance.
The tip 8 is a bowl-shaped body (flattened hemispherical dome) having a curved surface that gently descends over the toe side and the surrounding side surface with the upper part of the foot opening 9 being the highest position. The accommodation space 12 having a volume enough to cover the entire foot is formed on the inner surface.

A lower side bent portion 13 that is a flange-like band width edge that is bent inward is provided on the outer periphery of the lower end of the lead core 8. The lower side bent portion 13 is a portion generally referred to as a skirt. In the case of a steel tip, the lower side bent portion 13 is a portion whose shape and the like are defined by JIS standards. In the present embodiment, the width of the lower side bent portion 13 is not uniform, and the width of the left and right portions in the vicinity of the tip portion and the opening 9 is formed wide as protruding pieces (14, 15, 16).
The lower side bent portion 13 will be described with reference to the bottom view shown in FIG. 3C. The outer shape is a tapered shape as a shoe tip like the lower end shape of the shell, and the shape of the sole side opening 10 is M. The shape is similar to the mold. The thickness of the lower bent portion 13 is about 1 to 2 mm.
Further, two triangular pyramidal projections 17 (17a, 17b, 17c, 17d) are provided on the upper surfaces of the left and right lower bent portions (protruding pieces 15, 16) in the vicinity of the foot opening 9 respectively. ing. The height of the protrusion 17 is about 1 mm, and has a gently inclined edge from the apex toward the opening 2, and the portion from the apex toward the tip side has an inclined surface with a relatively steep angle. (See FIG. 3D).
The protrusion 17 is designed to bite into the engaging portion on the bottom surface of the core mold when the tip 8 is attached to the shoe mold, and has a gentle resistance due to the gentle inclined edge so that it does not come out due to the sharp side surface. It acts on. The shape of the protrusion 17 is not limited to the shape shown in the figure, and it is preferable that the protrusion 17 has a small resistance when mounted and a large resistance in the drop-off direction.

FIG. 4 is an explanatory view showing the side surface of the core mold 3 with the backing cloth 7 and the tip 8 attached as a cross-sectional view.
Engagement means for forming a gap t with the tip 8 and engaging with the tip 8 is provided at the toe portion of the core mold 3 to which the tip 8 is mounted. An example of the engaging means is an upper projection 18 projecting from the upper surface and a bottom projection 19 projecting from the bottom surface. A plurality of upper protrusions 18 are provided on the toe part upper surface of the core mold 3, and a space t is provided between the inner surface of the tip 8 and the core mold 3, and the pressing force accompanying the elasticity of the tip 8 is used. It has a function of generating a frictional force and fixing the tip 8.
The upper projection 18 can also adopt a structural fitting structure with the tip 8 similarly to the bottom projection 19 described below. In this case, engagement means corresponding to the upper projection 18 is also formed on the inner surface of the tip 8.

The bottom projection 19 faces the projection 17 (17a, 17b, 17c, 17d) which is a projection provided on the skirt portion (lower side bent portion 13) of the tip 8 on the bottom surface of the core mold 3. They are formed to engage with each other.
The shape of the bottom projection 19 is a quadrangular columnar shape in which a recess 20 is formed in the center of the tip surface (top surface), and by engaging the protruding end of the projection 17 provided on the lower bent portion 13 with the recess 20, The tip 8 attached to the core mold 3 is prevented from falling off.
Further, a protrusion (tip protrusion) 21 is also provided at the tip of the toe portion of the core mold 3, and the gap t between the core mold 3 and the tip 8 can be appropriately maintained together with the above-described protrusions. It is like that.
Since the tip 8 is made of a synthetic resin and the projecting pieces 15 and 16 are formed near the opening end of the tip 3, the tip 8 is fixed when the tip 8 is fixed to the core mold 3. The eight protruding pieces 15 and 16 are easily elastically deformed in a direction away from the bottom protrusion 19 and can be easily fixed by human power.

Next, some examples relating to the structure of the engaging portion on the bottom surface of the core mold 3 and the engaged portion formed in the lower side bent portion 13 of the tip 8 will be described based on the table shown in FIG.
FIG. 5 shows the first to sixth examples in which the shape of the engaged portion on the front core side is the left column, the shape of the engaging portion on the mold side is the middle column, and the engaging portions are fitted together. Cross-sectional views simply showing the state are shown in the right column. In addition, the engagement between the engaged portion and the engaging portion shown in each example is performed in a state where a backing cloth constituting the inner surface of the shoe is interposed, and the shapes of the engaged portion and the engaging portion are Although it is designed on the assumption that the backing cloth is interposed, the explanation of the backing cloth is omitted in the following description.

  The first example relates to the above-described embodiment, and is provided with a triangular pyramid-shaped protrusion 17 having a different inclination angle from the apex in the front-rear direction at the lower side bent portion 13 of the lead core, and the bottom surface of the core mold 3 As the bottom projection 19, a quadrangular prism-shaped projection having a recess 20 formed in the center of the tip surface (top surface) is formed. The engagement state between the projection 17 of the tip 8 and the bottom projection 19 of the core mold shown in this example is as shown in the simplified cross-sectional view in the right column of the table, and the tip of the recess 20 on the tip surface of the bottom projection 19 is the tip. The tip of the protrusion 17 of the core 8 enters, and both are joined by the elasticity of the material of the tip 8. The engagement structure as described above is employed in order to exert an effect that it is easy to fit and is not easily released by utilizing the property of the tip 8 formed of synthetic resin. In addition, the engagement structure is not limited to the above structure, and a structure in which a protrusion having a shape such as a bottom protrusion 19 is provided in the lower bent portion 13 and a protrusion such as a protrusion 17 is provided on the bottom surface of the core mold 3 is employed. It doesn't matter.

  In the second example, the shape of the engaged portion formed on the tip 8 is a triangular pyramidal projection 17 as in the first example, whereas the shape of the engaging portion on the bottom surface of the core mold 3 is the same. Is a ridge 21 shaped like a rectangular column lying down sideways. The protrusions 21 are provided such that the longitudinal direction is substantially perpendicular to the mounting direction of the tip 8, and the protrusion 17 of the tip 8 protrudes by a relatively gentle inclined edge when the tip 8 is mounted. After overcoming and overcoming the strip 21, it is difficult to return by the action of the steeply inclined surface of the protrusion 17. Further, since the ridges 21 protrude toward the inner surface of the tip 8, a fixed gap t is formed between the surface of the core mold and the inner surface of the tip 8. Further, the engagement structure is not limited to the above structure, and a structure in which a protrusion having a shape like the ridge 21 is provided in the lower bent portion 13 and a protrusion such as the protrusion 17 is provided on the bottom surface of the core mold 3 is provided. It does not matter.

  The third example is constituted by hemispherical protrusions 22 in which the engaged parts formed on the tip 8 are arranged at equal intervals, and the engaging part on the bottom surface of the core mold 3 facing the arrangement of the protrusions 22 is also provided. It is constituted by hemispherical protrusions 23 arranged at almost equal intervals. The arrangement intervals of the hemispherical protrusions 22 and 23 facing each other are substantially equal, and the position is fixed when one protrusion enters the gap between the other protrusions. The advantage of this structure is that, even if the opposing position of the engaged portion of the tip 8 and the engaging portion of the bottom surface of the core mold 3 is not accurate, any of the protrusions are engaged with each other and the gap t is maintained. That is, it is possible to prevent the tip 8 from dropping from the mold 3.

In the fourth example, the engaged portion formed on the tip 8 is formed as a prismatic ridge 24 having a parallelogram-shaped cross section in which the front and rear surfaces are parallel inclined surfaces having substantially the same angle. The engaging portion of the bottom surface of the core mold 3 is also formed as a prismatic ridge 25 similar to the ridge 24 having both front and rear surfaces having parallel inclined surfaces having substantially the same angle.
The inclined surfaces of both convex shapes 24 and 25 form substantially the same angle in a state of being opposed to each other, and when the tip 8 is mounted, the ridge 24 of the tip 8 gets over the ridge 25 of the core mold. When the front core 8 tries to return after getting over, the inclined surfaces act so as to draw each other and prevent the front core 8 from falling off the core mold.
In addition, although the illustrated example has shown the case where the convex shape 24 and the convex line 25 are each one, it is good also as a structure which provided the same multiple convex line.

In the fifth example, the engaged portion formed on the tip 8 is configured as a plurality of ridges 26 having a triangular cross section, and the engaging portion on the bottom surface of the core mold 3 is also triangular in cross section. In this configuration, a plurality of convex ridges 27 are provided.
The inclined surfaces of the two ridges 26 and 27 are formed at substantially the same angle in a state of being opposed to each other, and the ridge 26 of the tip 8 gets over the protrusion 27 of the core mold 3 when the tip 8 is mounted. After climbing over, the inclined surfaces are engaged with each other to prevent the tip 8 from falling off the core mold 3.

  In the sixth example, the engaged portion formed on the tip 8 is a cone 28 having a triangular cross section, and the engaging portion on the bottom surface of the core mold 3 is engageable with the apex portion of the cone 28. The concave portion 29 is used. The apex portion of the cone 28 of the attached tip 8 enters the concave portion 29 of the core mold by the elasticity of the tip 8 and is pressed to prevent the tip 8 from falling off the core mold 3. In addition, the engagement structure is not limited to the above structure, and a structure in which a recess having a shape like a recess 29 is provided in the lower bent portion 13 and a projection such as a cone 28 is provided on the bottom surface of the core mold 3. It does not matter.

As described above, the method for manufacturing a shoe according to the present invention provides an engagement portion on a core mold, and an engagement portion that engages with the engagement portion is also formed on the tip of the core mold. In addition to preventing the tip from falling off, a gap filled with the injected synthetic resin can be provided between the core mold and the tip.
In some large-sized injection molding apparatuses, the core mold is arranged in a vertical orientation as shown in FIG. That is, the tip of the toe is facing down, but when the tip is attached to the tip of the core mold in this state, the tip will drop if there is no appropriate engagement means. In the case of an iron tip, the tip can be adsorbed by providing a neodymium magnet on the surface of the core mold. However, an adsorption method using a magnet cannot be employed with a tip made of synthetic resin. In the present invention, even in a molding apparatus in which such a toe faces downward, the core die can hold the tip.
In addition, although the injection molding device has different injection port positions depending on the manufacturer, for example, when the injection port is provided near the heel, the molding material flows from the heel side toward the toe side. There is a possibility that the core material 3 may fall off when pressed against the toe side by the molding material. In order to prevent such inconvenience, if the injection port 30 is arranged on the toe side as shown in FIG. 6 and the tip 8 is injected so as to be pressed toward the heel direction by the injection material, the tip 8 falls off. Can be prevented.
Moreover, this invention can arrange | position a back cloth on the inner surface of shoes also in the toe part which provided the tip. Often used as a lining fabric for boots is a knitted fabric of synthetic fibers having a thin wire diameter, as typified by pantyhose for women. Since the backing cloth has a fine mesh, the injected resin is solidified with the backing cloth pressed against the core mold, and as a result, the backing cloth appears on the inner surface of the shoe. Further, since the synthetic fiber knitted fabric with a small wire diameter is thin, soft and flexible, it has a property that it is difficult to inhibit the engagement between the engaging portion of the core mold and the engaged portion of the tip. Yes, it is an optimal backing fabric in the present invention.
As shown in FIG. 7, the molded boots are demolded by pulling the heel portion away from the bottom surface 32 of the core mold 3 (in the direction of arrow A). For this reason, the inner bottom 31 of the boots is easily separated from the bottom surface 32 as it is closer to the heel, and is less likely to be separated from the bottom surface 32 as it is closer to the toe. Therefore, it is easier to remove the protrusion 17 of the tip 8 as close to the heel as possible, and the configuration in which the protrusions 17 are provided on the lower bent portions 13 and 15 as in this embodiment is suitable. I can say that.

The invention of the present application can be used for a method of manufacturing a shoe incorporating a tip by injection molding.

It is the schematic of the manufacturing apparatus of the shoes used for this invention. It is explanatory drawing for demonstrating the manufacturing process of shoes. It is explanatory drawing of the tip used for this invention. It is explanatory drawing which shows the mounting state body of the tip with respect to a metal mold | die. It is explanatory drawing which shows the example of mounting | wearing with a metal mold | die and a tip. It is sectional drawing of the manufacturing apparatus of the shoes used for this invention. It is explanatory drawing (sectional drawing) for demonstrating a process of the molded boots from a metal mold | die.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Injection molding apparatus 2 Boots 3 Core metal mold | die 4, 5 Side mold 6 Bottom mold 7 Back cloth 9 Opening 10 Opening 13 Lower side bending part 14, 15, 16 Projection piece 17 (17a, 17b, 17c, 17d) Protrusion 19 Bottom part Projection 20 Dimple 21 Projection 22 Projection 23 Projection 24 Projection 25 Projection 26 Projection 27 Projection 27 Projection 28 Cone 29 Concave

Claims (2)

A shoe manufacturing method formed by a core mold that forms the inside of a shoe and a cavity mold that forms the outer shape of the shoe,
Having a toe with a lower bent portion to be attached to the toe part of the core mold,
The toe portion of the core mold to which the tip is attached is provided with an upper projection that protrudes from the upper surface and a bottom projection that protrudes from the bottom surface, forming a gap with the tip,
Preventing the tip from dropping off from the core mold by forming an engaged portion that engages with a bottom protrusion of the core mold on the upper surface of the lower bent portion of the tip;
A gap is formed on the inner side surface of the tip core between the upper side surface and the bottom side surface of the core mold, and the thermoplastic resin is also formed in the gap formed by the tip core and the core mold during injection molding. A method for manufacturing a shoe, characterized in that the shoe is filled. The shoe manufacturing method according to claim 1, wherein the tip is formed of a synthetic resin.