JPS646862Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention was developed for baseball fields, soccer stadiums, competition tracks, etc., which are constructed by laying artificial grass on the surface.
This invention relates to the improvement of athletic fields such as tennis courts, especially their artificial turf surfaces.

In recent years, an increasing number of baseball stadiums have adopted artificial turf, but there have been reports of physical injuries among players that appear to be caused by the artificial turf. Although the medical explanation of the cause and effect relationship has not yet been clarified, there are cases where a player's spikes stick into the grain of the artificial turf and cause him to trip, or when the sole of his shoe hits when he tries to stop quickly to catch or throw a ball. This is due to the fact that the artificial turf cannot sufficiently absorb the enormous load instantaneously applied through the grass, and as a result, a strong impact is applied to the ankles, knee joints, thighs, etc. of the players as a reaction force. Guessed. In order to respond to this situation,
Athletic shoes equipped with hemispherical spikes have already been proposed, but the hemispherical spikes are not practical and have not been widely used because they encourage slipping on artificial turf.

In view of this situation, the present applicant first added silicate mineral grains (i.e., inorganic granules) such as river sand, sea sand, and silica sand, cork grains, coarsely crushed coconut shell grains, By scattering and filling vulcanized rubber particles (i.e. organic granules) etc. to a predetermined thickness, the plastic deformation of the granules (sand) instantly applies impact force, just like a golf ball hit into a bunker. Invention that can effectively prevent the tip of a spike from getting caught in the grass grain (patent application filed in 1983)
No. 105993 (Japanese Unexamined Patent Application Publication No. 1983-7005)).
According to this invention, in addition, it has an appropriate water absorbency that absorbs water droplets on the artificial lawn surface during rain, and a water retention capacity that prevents water from puddles on the lawn surface after rain, allowing play to be resumed within a short time. It has the advantage of being possible. However, subsequent experiments have shown that, especially when mineral particles are used, the wear of the artificial turf is accelerated by the friction between the artificial turf and granular materials such as fine sand that move as the player moves. It has been found.

Therefore, the purpose of this invention is to create an artificial lawn using granules filled in the grass grains without sacrificing the advantages of the previously proposed invention, namely, excellent shock-absorbing capacity and adequate water absorption and water retention capacity. The object of the present invention is to provide an athletic field in which wear can be prevented as much as possible.

This invention will be described in detail below based on embodiments shown in the accompanying drawings.

This athletic field includes an artificial lawn 2 laid on a foundation 1. The foundation 1 is made up of a layer of grain-grained crushed stone 3 and a dense-grained asphalt layer layered one after another on a roadbed (not shown) constructed by digging down the ground.
It consists of 4 concrete layers. The artificial lawn 2 may be of any known type; for example, it may have a structure in which countless elongated strips are integrally erected on the base 1 by molding using a synthetic resin such as polyamide or polyurethane. However, it is preferable to use artificial turf that is more similar to natural grass in terms of appearance and texture, and that has resistance to set and is closely related to conditions in athletics such as ball bounce and slipping of shoe soles. From the viewpoint of physical and mechanical properties such as tensile strength, tear strength, weather resistance, and dimensional stability, which are related to durability, polyamide,
Slit yarn made by slicing films such as polyethylene terephthalate, polyurethane, polyvinylidene chloride, polypropylene, etc. can be used as pile yarn, or
Or, by melt-spinning, a flat yarn is made through a nozzle with an irregularly shaped cross-sectional hole, and this is used as a pile yarn.
A structure formed by flocking these pile yarns to the backing base fabric 5 is preferable.

A granular material layer 6 mainly made of inorganic material is formed within the grass grains of this artificial lawn 2. This granular material layer 6 is filled in the turf by scattering it on the artificial lawn 2, and the granular materials used include silicate mineral particles (i.e., inorganic mineral particles) such as river sand, sea sand, and silica sand. Particularly, after adjusting the particle size of the mineral particles, the dried particles are heated and dehydrated to absorb the water retained in the artificial lawn 2 and more quickly restore the dry state. In addition, the particle size is preferably about so-called silica sand No. 5 to No. 8. The thickness of the granular material layer 6 is determined in consideration of the buffering performance, spike prevention ability, moisture absorption ability, etc. required depending on the type of stadium to which it is applied (baseball, soccer, tennis, etc.). It will be done. For example, artificial grass 2 with a length of 5-30 mm
In this case, the granular material layer 6 is scattered and filled into the grass grain so that the leaf tips 2a protrude by about 2 to 15 mm.
Incidentally, organic particles having appropriate elasticity in addition to water absorbency, for example, crushed particles such as cork grains and coconut shells may be mixed into the granular material layer 6. Also,
In addition, it is also possible to use pulverized vulcanized rubber or plastic, especially foamed plastic, as the organic particles. Although these pulverized products are not as good as the aforementioned silica sand or cork grains in terms of water absorption, they are effective in reinforcing the sagging resistance of the artificial lawn 2 and giving it appropriate elasticity. and,
In this invention, at least the surface layer of the granular material layer 6 is composed of spherical granular materials 7 that are artificially formed in advance into a substantially spherical shape. The spherical particles 7 are made of, for example, glass beads, and have a particle size of 1 mm or less, preferably about 200 μm. The shape may be any rounded shape with no corners, such as a perfect round sphere or an elliptical sphere. Further, the thickness of the surface layer made of the spherical particles 7 is preferably at least about 1/3 of the thickness of the granule layer 6.
Of course, the granule layer 6 may be entirely composed of spherical granules 7, but this would be expensive, so the amount described above is sufficient to achieve the purpose of this invention.

According to this invention, as described above, the surface layer of the granular material layer 6 mainly composed of mineral grains such as river sand or sea sand, which is scattered and filled into the turf of the artificial lawn, is composed of spherical granular materials 7 such as glass beads. Because it has been
These spherical particles 7 act like a lubricant,
Abrasion of artificial grass caused by rubbing against mineral grains is reduced. Therefore, the useful life of the artificial lawn can be greatly extended without impairing its shock-absorbing ability or appropriate water absorption and water retention ability, making it extremely practical.

[Brief explanation of the drawing]

The drawing is a partial cross-sectional view of an artificial grass sports stadium according to this invention. In the figure, 1 is a base, 2 is an artificial lawn, 6 is a layer of granular material such as river sand, and 7 is a spherical granular material such as glass beads.

Claims (1)

[Scope of Claim for Utility Model Registration] In an athletic field formed by laying an artificial lawn on a base made of cement, asphalt, etc., and scattering and filling inorganic granules, mainly river sand, into the turf of the artificial lawn, the above-mentioned: An athletic field made of artificial grass, characterized in that the surface layer of the granular material is made of spherical granular material such as glass beads that are artificially formed into a substantially spherical shape.