JP2018033705A - Toe box - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide, in a toe box having shock resistance satisfying prescribed specifications, a resin toe box for safety shoes and the like having shock resistance satisfying higher performance specifications than the prescribed specifications without significantly changing an external shape, weight, or the like.SOLUTION: A toe box 1 for protecting toes, to be incorporated in a shoe tip of a work shoe, includes: a toe box body 2 that is integrally formed of a synthetic resin material so as to cover toes by a shell continuing across a tip end wall 3, a left side wall 4, a right side wall 5, and an upper wall 6 in a gentle curve; and a woven cloth that forms the front/back of the upper wall 6 into a planar surface without any irregularity, and is formed of nylon resin fibers on the surface of the upper wall 6 via an adhesive layer. Further the toe box body 2 is formed of nylon resin reinforced by glass fibers.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a tip used for work shoes such as safety shoes.

Patent Document 1 discloses a thin-layer reinforcing structure in which a reinforcing layer is provided on a base layer body. The thin-layer reinforcing structure has a base layer body such as a safety shoe head manufactured from a fiber-reinforced thermosolid resin, and the base layer body is provided with a reinforcing layer. The reinforcing layer is produced by immersing a thermoplastic resin fiber woven fabric in a thermosolid resin, and is provided in a single layer or a plurality of layers in the form of a laminated structure inside the base layer body.
The base layer is manufactured by adding a fiber such as glass fiber to a heat solid resin such as epoxy resin or phenol resin, and the thermoplastic resin fiber woven fabric is a fiber having a melting point of 160 to 260 degrees such as nylon and PET fiber. 900 to 4800 denier woven fabric is best described.

  The thin-layer reinforcing structure is intended to increase the strength of a safety shoe head or the like by providing a reinforcing layer on the surface of the base layer body. This reinforcing layer is manufactured from a fiber-reinforced thermosolid resin. The base layer body is used to immerse a thermoplastic resin fiber woven fabric in a thermosolid resin. That is, when the base layer body is constructed, it is immersed in a thermosolid resin (thermosetting resin) such as an epoxy resin or a phenol resin, and the reinforcing layer is integrally provided together with the curing of the thermosolid resin constituting the base layer body. is there.

Utility Model Registration No. 3094797 Japanese Patent No. 5154699

Since the thin layer type reinforcing structure is provided with a reinforcing layer integrally with the resin constituting the base layer body, the resin constituting the base layer body is injected after the reinforcing layer is disposed inside the mold. Requires a process.
In addition, the thin layer type reinforcing structure is cured in such a state that the thermosolid resin constituting the base layer body enters the cloth of the woven fabric constituting the reinforcement layer. A fine unevenness is formed. That is, fine irregularities such as a stitch pattern are formed on the surface of the base layer body (boundary with the reinforcing layer). However, when it is intended to suppress the occurrence of cracks that occur when subjected to an impact, it is preferable not to form irregularities on the surface portion of the base layer body.

  Further, as an evaluation method of the tip for safety shoes, there is an impact resistance test in which a striker is allowed to fall freely and collide. In this impact resistance test, there are H class (100J), S class (70J), L class (30J) and Canadian CSA standard class I (120J) as defined in Japanese JIS standards. J is a joule and is a unit representing the striker's fall energy (collision energy). The applicant has implemented the steel tip as described in Patent Document 2 above, but also implemented a resin tip that is formed of a resin containing glass fiber in a shape in which the side edge is extended to the little finger side similar to this. doing. This resin-made lead core is formed so as to satisfy the above-mentioned S type (70J) of the JIS standard, but it is necessary to further satisfy the CSA standard (120J).

  The present invention has been invented in view of the above circumstances, and has impact resistance performance that satisfies the CSA standard 120J without greatly changing the outer shape, weight, etc. of the tip that satisfies the S type of the JIS standard. An object of the present invention is to provide a resin tip for safety shoes.

A tip for protecting the toes built in the shoe tips of the work shoes,
With a synthetic resin material, the front end wall, the left side wall, the right side wall, and the top wall have a toe core body that is integrally formed so as to cover the foot tip with a continuous curved body with a gently curved surface,
The top and bottom surfaces of the upper surface wall are formed into a smooth surface without irregularities, and a woven fabric formed of nylon resin fibers is provided on the upper surface of the upper surface wall via an adhesive layer.

The present invention relates to a tip core built in a shoe for protecting a foot tip such as a safety shoe, and provides a structure and a manufacturing method of a resin tip core having improved impact strength.
That is, the present invention is a nylon resin having a tip core body formed so as to satisfy a certain degree of impact resistance, such as JIS standard S type (70J), and bonded to the top wall of the tip core body. The fiber was able to greatly improve the impact resistance.
In this structure, the tip core body is formed so as to satisfy a certain degree of impact resistance, but the mechanical properties of the tip core body are not deteriorated by attaching the nylon resin fiber. And, as shown in the test results to be described later as an example, only affixing the nylon resin fiber has an effect that a significant improvement in impact resistance performance of 70J to 120J or more can be realized.

Also, the tip core body is made of resin reinforced with so-called glass fiber, but if there are corners or irregularities on the surface, cracks are likely to occur due to impact, so the surface is formed as a smooth surface without acute corners or irregularities Yes.
In addition, since the invention only applies the nylon resin fiber woven fabric through an adhesive, the surface of the tip core body is not damaged, and no solvent or adhesive that affects the composition is used. The woven fabric application itself has the effect of not reducing the strength inherent to the core body.

It is an external appearance perspective view of the lead core concerning this embodiment. It is a top view of the tip which concerns on this Embodiment. It is a bottom view of the lead core concerning this embodiment. 3 is an appearance photograph showing the result of an impact resistance test of Sample A. 3 is an appearance photograph showing the result of an impact resistance test of Sample B. 3 is an appearance photograph showing the result of an impact resistance test of Sample C. 3 is an appearance photograph showing the result of an impact resistance test of Sample D. It is explanatory drawing of a test method.

Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings.
FIG. 1 is an external perspective view of a toe for work shoes (hereinafter referred to as “tip”) 1 such as safety shoes according to the present embodiment. FIG. 2 is a plan view of the tip 1 seen from the upper surface side, and FIG. 3 is a bottom view of the tip 1 seen from the back side. 1 to 3 show the tip to be built in the shoe for the left foot, but the tip to be built in the shoe for the right foot has a shape symmetrical to that shown in the drawings. Since the function and effect are the same, the explanation for the right foot is omitted.

The tip 1 has a tip core body 2 in which a synthetic resin containing glass fiber (glass fiber) is formed as an integral shell by pressure molding with heating. As this synthetic resin, polycarbonate, PC alloy (copolymer resin such as polycarbonate and PBT resin), ABS, PET, preferably polypropylene, nylon having excellent chemical resistance, etc. excellent in impact resistance, ease of molding, etc. Can be adopted.
The toe core body 2 is formed as a shell constituting the toe portion of the shoe, and has a shape that protects the toe portion with the finger at the center by being incorporated in the tip portion of the upper of the shoe. have. The tip core body 2 has a tip wall 3 constituting a tip portion on the foot tip side, a left side wall 4 facing rearward from the tip wall 3, a right side wall 5, and an upper surface wall 6 covering an upper portion of the tip portion. Each wall is formed as a shell having a bowl-shaped portion formed so as to be continuous with a gentle curved surface. The inner surface of the mold for molding the lead core body 2 is formed without irregularities so as not to form sharp corners, and the surface portion visible from the appearance of the molded lead core body 2 is smooth without scratches or irregularities. It is formed as a surface.

  Further, at the lower ends of the tip wall 3, the left side wall 4, and the right side wall 5, an edge portion (skirt 7) having a predetermined width is provided by bending the lower end edge inward. The skirt 7 prevents the tip 1 from being deformed by a load or an impact, and prevents the tip 1 from sinking into a shoe sole formed of a resilient material such as rubber or urethane. It has the effect | action which prevents constriction of the space which accommodates a foot tip, and prevents pressure on a foot tip.

  Further, the tip core body 2 has a shape in which the rear end of the side wall on the little finger side of the tip core body 2 is extended rearward longer than the rear end edge 11 of the top wall in order to protect the side surface side of the little finger. doing. An upper surface wall is not provided on the extended side wall portion 8 so as not to disturb the bending operation of the toes during walking or in the heel posture.

A woven fabric (first woven fabric) 9 formed of nylon resin fibers is attached to the surface on the upper surface side of the upper surface wall 6 of the tip core body 2 having the above-described shape through an adhesive layer. The first woven fabric 9 is optimally woven at a high density satisfying the performance that can be used for an in-vehicle airbag. For example, a woven fabric woven from nylon 66 and nylon 6 fibers is used. ing.
This woven fabric is affixed to the surface of the top wall of the tip core body 2 using an adhesive. A urethane-based adhesive is used as the adhesive. Urethane adhesives are highly flexible and have excellent impact resistance.
In addition, a woven fabric (second woven fabric) 10 formed of nylon resin fibers is attached to the back surface of the top wall of the tip core body 2 via an adhesive layer. The second woven fabric 10 is optimally woven at a high density that satisfies the performance that can be used for an in-vehicle airbag. For example, a woven fabric woven from fibers formed of nylon 66 and nylon 6 is used. ing. The second woven fabric 10 is formed in a substantially semicircular shape in accordance with the shape of the back surface of the upper surface wall, and the straight portion is substantially coincided with the rear end edge 11 of the upper surface wall. It is pasted so as to form a fan shape from the approximate center toward the front part.

  The first woven fabric 9 and the second woven fabric 10 are bonded to the core body 2 using an adhesive. As this adhesive, a component that does not dissolve or damage the first woven fabric 9 and the second woven fabric 10 made of nylon is used. Further, since heating and pressurization that change the composition of the woven fabric at the time of bonding are not performed, the reinforcing action of the core body 2 can be exhibited without impairing the strength and mechanical properties of the woven fabric. It is like that.

The first woven fabric 9 is formed in a substantially semicircular shape in accordance with the shape of the upper surface of the upper surface wall 6, and the linear portion is substantially coincided with the rear edge 11 of the upper surface wall. It is affixed so as to form a fan shape from the approximate center to the front part.
The upper surface wall is a portion formed as a slope that gently slopes downward toward the front and sides with the approximate center of the rear end edge 11 as a vertex, and is formed as a smooth surface that forms a gently curved surface. The tip wall 3, the left side wall 4, and the right side wall 5 described above are connected so as to hang down through a curved portion 12 bent downward with a curvature that does not form a square portion in the outer periphery of the upper surface wall 6. ing.

The first woven fabric 9 is bonded to the upper surface of the upper surface wall 6 but is provided so as not to cover the surface of the curved portion connecting the tip wall 3, the left side wall 4, and the right side wall 5 described above.
The outer skin that forms the exterior of the shoe attached to the shoe sole is called the upper body. The upper body is formed by sewing a sheet of leather or the like, and is formed into a three-dimensional bag shape according to the shape of the foot using a shoe shape (wooden shape) together with an insole. At this time, a process of pulling and fixing the lower end of the upper body to the insole side is performed, and the upper body is brought into close contact with the shoe mold to which the tip 1 is attached, thereby adjusting the shape as the footrest portion. ing.

The above-described suspension pulls the outer periphery of the outer skin (also referred to as “skin”) including the toe portion toward the shoe sole side, and has the effect of closely contacting the surface of the tip 1. At this time, it is possible to prevent wrinkles from occurring in the portion constituting the toe portion due to the tension acting on the outer skin, to keep the aesthetic appearance of the shoe tip portion and to hold the tip 1.
The outer skin in contact with the surface of the tip 1 is strongly pressed against the tip 1 by pulling, but a resistance force against pulling is also generated by the accompanying frictional force. In this case, if the surface of the tip 1 is smooth, the outer skin is slippery and there is little resistance to pulling. However, if the surface is uneven or rough, the resistance increases and the entrainment becomes insufficient. In particular, since a strong pressing force acts on the curved portion 12 connecting the tip wall 3, the left side wall 4, the right side wall 5 and the upper surface wall 6, if the surface of the part is a rough surface, the suspension becomes insufficient. End up.
For this reason, the first woven fabric is used so that the surface of the curved portion 12 connecting the tip wall 3, the left side wall 4, the right side wall 5 and the upper surface wall 6 does not become rough due to the texture of the first woven fabric 9. The curved portion 12 is not covered. That is, the first woven fabric 9 is provided on the upper surface of the upper surface wall 6 excluding the curved portion 12.

Next, the result of the impact test of the tip 1 having the above configuration will be described. The test is to test whether or not the above-mentioned CSA standard (120J) is satisfied. A cylindrical striker with a diameter of 25.4 mm (1 inch) having a tip formed on a spherical surface with a radius of 25.4 mm (1 inch). ST is performed by dropping from a height of 1 m with a 12 kg weight.
Table 1 shows the results of the impact resistance test in the case of the type of woven fabric affixed to the main body and the absence of the woven fabric. The tip core bodies used for the samples A to D to be tested are all made of the same shape and the same material, and different types of woven fabrics are attached to each sample to make each sample. The core body is formed of a material obtained by adding glass fibers to nylon 6 at a volume ratio of 40%.

Explain the contents and test results of each sample.
Sample A uses a woven fabric formed of nylon resin fibers having a wire diameter of 0.021 mm (actual value) with respect to the front core body, using an adhesive on the upper and lower surfaces (upper surface and back surface) of the upper surface wall of the front core body. It is pasted. The thickness of the woven fabric was 0.3 mm.
In the test, the oil clay N formed in a cylindrical shape is accommodated in the tip core body (the inner surface of the opening is 44 mm in height), and the striker is dropped in this state to deform the oil clay N (the height of the inner surface is 44 mm). -Oil clay N residual height) and the presence or absence of damage to the core body (see FIG. 8).
The test result of sample A was 18.8 mm in the downward deformation amount of the core body calculated from the deformation amount of the oil clay N, and the deformation ratio with respect to the total height of 44 mm was about 42.7 percent. In the impact resistance test of Sample A, no damage was caused to the tip body as shown in the photograph in FIG. 4A shows the appearance of the sample A on the plane (upper surface) side, and FIG. 4B shows the appearance of the sample A on the bottom surface side.

Sample B is a woven fabric formed of nylon resin fibers having a wire diameter of 0.043 mm (actual value) attached to the front core body using an adhesive on the front and back of the top wall of the front core body. is there. The thickness of the woven fabric was 0.3 mm. Sample B is made by attaching a woven fabric made of nylon resin fibers in the same manner as Sample A, but uses nylon resin fibers having a large wire diameter used for the woven fabric.
The test result of sample B was that the amount of deformation of the tip core body calculated downward from the amount of deformation of oil clay N was 19.0 mm, and the deformation ratio with respect to the total height of 44 mm was about 43.2 percent. In the impact resistance test of Sample B, no damage was caused to the tip body as shown in the photograph shown in FIG. 5A shows the appearance of the sample B on the plane (upper surface) side, and FIG. 5B shows the appearance of the sample B on the bottom surface side.

In Sample C, a woven fabric formed of polyester fiber (product number: T5110S NT251) having a wire diameter of 0.028 mm (actual value) is used for the front core body, and adhesive is used on the front and back of the top wall of the front core body. Is pasted. The thickness of the woven fabric was 0.2 mm.
The test result of Sample C was that the amount of deformation of the tip core body calculated from the amount of deformation of the oil clay N was 19.9 mm, and the deformation ratio with respect to the total height of 44 mm was about 45.2 percent. Then, in the impact resistance test of sample C, as shown in the photograph shown in FIG. 6, the tip core body was cracked (see C1 location in FIG. 6 (a), C2 location in FIG. 6 (b)). Here, FIG. 6A shows the appearance of the sample C on the plane (upper surface) side, and FIG. 6B shows the appearance of the sample C on the bottom surface side.

Sample D is formed so as to satisfy Japanese JIS standard S type (70J), and is a core body itself to which a woven fabric is not attached.
The test result of Sample D was a deformation amount of 22.1 m and a deformation ratio with respect to the total height of 44 mm was about 50.2 percent. As shown in the photograph of FIG. 7, the tip core body was damaged (refer to the D1 position in FIG. 7A and the D2 position in FIG. 7B). That is, although it can withstand the above-mentioned S type (70J), it could not withstand an impact load of 120J, which exceeds this by 50J. 7A shows the appearance of the sample D on the plane (upper surface) side, and FIG. 7B shows the appearance of the sample D on the bottom surface side.

As described above, the deformation ratio of the sample A is about 42.7%, and the deformation ratio of the sample B is about 43.2%. In these cases, the tip core body is not damaged. On the other hand, the deformation ratio of sample C was about 45.2%, and the deformation ratio of sample D was about 50.2%. In these cases, the tip core body was damaged.
From the above results, nylon resin fiber woven fabric can reduce the amount of deformation when subjected to impact load compared to woven fabric of other materials, thereby preventing damage to the tip. It is possible.

  The non-reinforced nylon 66 has a tensile strength of 48-67 Mpa, and the nylon 6 has a tensile strength of 41-166 Mpa. On the other hand, the tensile strength of polyethylene is 23-31 MPa. Comparing the mechanical properties considered to be involved in deformation resistance, it can be said that nylon is about twice as good as polyethylene, and this also indicates that nylon was suitable as a woven fabric.

Since the tip core 1 according to the present invention is affixed with a nylon resin fiber woven fabric only through an adhesive, it does not have a structural influence such as damaging the surface of the tip core body. The strength and properties of the main body are not impaired.
Further, as a method of providing a woven fabric on the surface of the tip core body, a woven fabric is placed in advance in a molding die, and a resin body that has been injection molded or heated in this state is pressure-molded like forging. A method is conceivable. However, in any case, since the woven fabric arranged in the mold moves due to pressure, it is difficult to integrally provide the woven fabric during molding. In this embodiment, the tip core body is formed of nylon resin mixed with glass fiber, but if the nylon resin is heated to melt or soften, the performance of the woven fabric made of nylon resin will naturally deteriorate. . From this point of view, the woven fabric cannot be provided using the mold. Further, if the woven fabric is to be bonded through the heating process, irregularities due to the texture of the woven fabric are formed on the surface of the tip core body, which causes a decrease in strength.
In this impact resistance test, a work shoe tip having a side wall portion 8 formed by extending the little finger side wall rearward was used, but a tip shape having a general shape without the side wall portion 8 ( For example, even when a Japanese Industrial Standard (JIS) “JIS T 8101” shaped tip is used, a test result substantially similar to the above test result can be obtained.

  As described above, as one of the means to greatly improve the impact resistance performance, a woven fabric made of nylon resin fibers is attached to the upper surface and the back surface of the top wall of the lead core body through an adhesive layer made of an adhesive. Has been found as the best method. This is because the top wall can be made into a multilayer structure by a relatively simple process without requiring a large facility, and the impact resistance of the tip core is made possible by the strength of each layer and the effect of interaction with the multilayer structure. It is intended to improve performance.

  The present invention can be used as a tip for safety shoes.

DESCRIPTION OF SYMBOLS 1 Lead core 2 Lead core main body 3 Front end wall 4 Left side wall 5 Right side wall 6 Upper surface wall 7 Skirt 8 Side wall part 9 Woven cloth 10 Woven cloth 11 Rear edge 12 Curved part

Claims (3)

A tip for protecting the toes built in the shoe tips of the work shoes,
With a synthetic resin material, the front end wall, the left side wall, the right side wall, and the top wall have a toe core body that is integrally formed so as to cover the foot tip with a continuous curved body with a gently curved surface,
A tip having a smooth surface with no irregularities on the front and back surfaces of the top wall, and a woven fabric formed of nylon resin fibers through an adhesive layer on the top surface of the top wall.   The tip core according to claim 1, wherein a woven fabric formed of nylon resin fibers is provided on the back surface of the top wall in addition to the top surface of the top wall through an adhesive layer.   The tip core according to claim 1 or 2, wherein the tip core body is made of a nylon resin reinforced with glass fiber.