JPS604403Y2 - Footwear bottom structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sole structure for footwear having high punch-through resistance.

・Conventionally, in order to provide footwear with trample resistance, a thin iron plate was inserted in the bottom of the footwear, but this method reduced the warp resistance of the bottom of the footwear, so there was one problem. If a strong bending force is applied to the bottom, problems such as peeling between the flexible rubber outsole and the steel plate occur.

In addition, if it is necessary to protect the toe area, it is necessary to insert a steel protective cover into the toe area1, but it is difficult to insert a toe cover into shoes with a steel plate in the bottom. there were.

Furthermore, jikatabi with steel plates for use at construction sites cannot provide sufficient sensation in the soles of the feet, which is required when crossing a narrow footpath.

Therefore, a prior art technique is known in which short glass fibers such as glass fibers are impregnated with a resin to form a sheet and then lined in the sole of the shoe.

However, according to this precedent, the glass fibers are not intertwined with each other and are bonded via resin, so if a sharp object such as a nail pierces the glass fibers,
The resin portion is expanded and the glass fibers are expanded accordingly.

In this way, the distance between the glass fibers increases and they are unable to maintain sufficient puncture resistance to withstand nails and the like.

In view of the above, an object of the present invention is to provide a sole structure for footwear that is lightweight, has both punch resistance and flexibility.

Hereinafter, the present invention 7 will be explained in detail with reference to the embodiments shown in the drawings.The sole structure of the footwear according to the present invention includes an outsole 1 and an insole 2, as only the bottom is shown in FIG. In between, a sheet 3 according to the present invention is interposed and fixed.

The sheet 3 is made by intertwining aromatic polyamide fibers 3a (trade name "KEVLAR" of DuPont Company, hereinafter referred to as Kevlar fibers) by means such as needle punching to form a felt-like cloth, as shown in FIGS. 2 I and II. As shown in the figure, the surface layer or the entire layer of this cloth is impregnated with a flexible synthetic resin or synthetic leather rubber 3b (hereinafter simply referred to as resin), and then heated to form a cloth.

The above-mentioned "needle 4 run" refers to a means of moving a needle with an arrowhead-shaped tip up and down within the fiber threads accumulated in no direction, thereby intertwining the mutual fibers and threads.

Further, the sheet 3 is made by knitting or weaving the fiber threads.

The fabric formed by this process may be impregnated with the resin 3b and heated.

Note that depending on the method of impregnation with the resin 3b, bubbles may remain in the sheet 3, but this does not pose any problem.

Kevlar fiber yarn 3a is lightweight and has high strength, and has approximately 5 times the tensile strength of polyester fiber (25 kg per denier), and is superior to other fiber yarns in terms of flexibility and heat insulation properties. Therefore, it is most suitable as the fiber yarn used for the sheet 3.

In the sheet 3 using the above felt cloth, the Kevlar fiber threads 3a are intricately intertwined, and the resin 3b fixes the Kevlar fiber threads 3a in an intertwined state, so there is no so-called stitch or weave.

That is, since there are few gaps between the Kevlar fiber threads 3a, the penetrating force against sharp objects such as nails is high.

That is, in the sheet 3, the Kevlar fiber threads 3a are closely intersected, and the resin 3b or synthetic rubber impregnated in the sheet 3 is closely bonded to the Kevlar fiber threads 3a in an entangled state. Therefore, the frictional force of the filled portion and the high tensile strength of the Kevlar fiber yarn group 3a effectively prevent the sharp object from entering.

At this time, since the mutual Kevlar fiber threads 3a are strongly bonded by the resin 3b, the spaces between the fiber threads 3a will not be forced apart by the sharp object.

In order to further improve the punch-through resistance, as shown in FIG. 3, an appropriate number of sheets, for example, three sheets 3□, 3□, 33, may be arranged in a layer and bonded to each other.

In this case, the sheet 3 made of felt cloth is used as the sheets 31 and 33, and the sheet made by the above-mentioned Knitting and Oribe is used as the sheet 3□, and various arrangements can be made depending on the intended use of the footwear. .

Of course, a soft rubber sheet may be interposed between each of the sheets to increase cushioning properties.

Here, A case where one piece of felt-like cloth with a thickness of 2 mm using the above-mentioned Kevlar fiber thread 3a is placed between the outsole and the inner sole of conventional firefighting rubber boots, and case B where two pieces are placed. The results of the punch-through resistance test are shown in C, a case in which one heated sheet impregnated with synthetic rubber to a thickness of 0.5 mm is placed on both surface layers of the felt-like cloth, and C in a case in which two sheets are placed. It is as follows.

This test was conducted using the test method specified in JIS5508 (Ta205), that is, the length was 65±31ftM1.
The test was conducted in accordance with a test method in which a round iron nail with a diameter of 3.05±0.08 mm was applied perpendicularly to the sole of a shoe, and then a static load was applied between the two.

As shown in the above test results, when two sheets are arranged, it is possible to prevent the round nail from penetrating even if a load equivalent to the body weight is applied to the shoe.

Of course, the punch-through resistance can be further improved by increasing the number of sheets and by using a sheet in which all layers of the felt cloth are impregnated with resin or synthetic rubber.

By the way, in order to provide conventional firefighting boots with enough punch-through resistance to prevent the nail from penetrating when an object weighing 50 cm and 9 is dropped onto which a 5-inch nail is applied, It is necessary to arrange a steel plate with a thickness of 0.5 mm or more between the outer sole and the inner sole.

On the other hand, since the bottom structure of the footwear of the present invention uses the sheet 3 having the above-mentioned configuration, it is possible to obtain the desired trample resistance without impairing flexibility and lightness, and therefore it is suitable for use in firefighting activities. Optimal.

In addition, since the sole structure of the footwear according to the present invention has a flexible sole, the force acting on the tread surface, that is, the shape of the object being stepped on, can be sensed with the sole of the foot.
It is effective as footwear, such as jikatabi, when working at high places such as on a framework.

Of course, the sole structure of the footwear of the present invention can also be applied to the sole structure of other types of footwear that require push-through resistance, such as athletic shoes, mountain climbing shoes, spikes, and flip-flops.

For example, in the above-mentioned flip-flops, the bottom part is made of the sheet 3 and a suitable woven fabric (for example, polyester fiber).
The cover of the toe portion is formed by impregnating the cloth shown in the above configuration example with a hard synthetic resin.

This makes it possible to obtain even greater punch-through resistance.

Other examples of the structure of the sheet 3 are as follows.

Arrange the Kevlar fibers in no direction, apply adhesive on top,
Next, Kevlar fibers are arranged on top of it in no direction, and adhesive is applied from above.

This process is repeated to form a felt-like cloth.

As mentioned above, according to the bottom structure of the footwear of the present invention,
Aromatic polyamide fibers are intertwined to form a felt-like cloth, and at least one surface layer of this cloth is impregnated with a flexible resin or synthetic rubber. Since the surface layer impregnated with the above-mentioned resin or synthetic rubber is placed on the front and bottom side, it is lighter than the conventional steel plate or glass fiber impregnated with resin. This makes it possible to improve flexibility and punch-through resistance.

In particular, since the aromatic polyamide fibers are shaped into a felt-like cloth, the knots are strong and can prevent sharp objects from penetrating without being pushed open.

In addition, since only the surface layer of the sheet is impregnated with resin or synthetic rubber, when a nail, etc. penetrates the surface layer and reaches the layer of fiber threads, the fiber threads will move freely as the tip of the nail penetrates. It deforms and absorbs pressure through its cushioning effect.

Therefore, the punch-through resistance can be significantly improved.

[Brief explanation of drawings]

Fig. 1 is a side view conceptually showing only the bottom part of an embodiment of the sole structure of footwear according to the present invention, and Figs. 2 I and II are
FIG. 3 is a partially enlarged vertical cross-sectional view showing how each sheet is impregnated with resin or synthetic rubber, and FIG. 3 is a partially enlarged vertical cross-sectional view showing one mode when a plurality of sheets are laminated. 1... Outer sole, 2... Inner sole, 3.3.
, 3□, 33...Sheet, 3a...Aromatic polyamide fiber (Kepler fiber yarn), 3b...
...Resin or synthetic rubber.

Claims (1)

[Scope of utility model registration request] Aromatic polyamide fibers are intertwined to form a felt-like cloth, and at least one surface layer of this cloth is impregnated with a flexible resin or synthetic rubber. 1. A bottom structure for footwear, characterized in that a surface layer impregnated with the above resin or synthetic rubber is placed between the bottom and the bottom of the footwear.