JPS62197079A - Sand containing athletic field made of artificial turf - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a sand-filled artificial lawn consisting of an artificial lawn laid on a substantially flat base and dry sand filled within the grain of the lawn. Regarding turf sports stadiums.

[Traditional technique]

The applicant has previously developed an artificial turf field laid on a substantially flat base by filling it with dry sand within the turf grains, thereby making it comparable in appearance and playing performance to a natural turf athletic field. Developed an earthen athletic field with artificial turf filled with sand (Registered utility model No. 11)
No. 74248) and has been used in many public and private sports facilities, including the official tennis courts of the Kobe Universiade. In addition, many technological developments were subsequently carried out to increase the practical value of the above-mentioned stadiums, such as the
He has applied for several dozen inventions, including No. 8-7005 and Utility Model Application Publication No. 128608/1983.

By the way, sand, which is a component of this type of stadium and is filled into the turf grains of artificial turf, is used to improve construction efficiency and to improve construction efficiency, as is clear from the contents of the public gazette cited above. Although it plays an extremely important role in providing excellent athletic performance in stadiums, drainage performance during rain, and maintaining these performances, it also includes practical problems that still need to be resolved.

〔Problems to be solved〕

Function of dry sand in sand-containing artificial turf earthen sports stadiums
One example of this is the movement of the sand particles and the buffering function due to the mutual friction between the particles, especially in the case of tennis courts, where the sand layer is too thick. If it moves easily, it will have a negative effect on the bouncing performance of the ball, so it is preferable that it is moderately compacted. Therefore, the particle size is approximately 0.1 to 1.7
Dry sand is used which lies within a wide range of mm.

With this configuration, a so-called "fine structure" (see Figure 3) in which relatively small-diameter sand particles are packed between relatively large-diameter sand particles within the above-mentioned range is created, and an appropriate hardness is created on the stadium surface. can be granted.

In the case of rugby fields, soccer fields, or golf course walking paths, the bouncing performance of the ball is not required to be as strict as in the case of tennis courts, and in fact, the easier movement of sand particles causes fatigue to the players' legs and lower back. This is preferable because it does not cause problems or problems.

Furthermore, in sand-containing artificial turf earthen sports stadiums, the sand layer generally becomes excessively compacted over time due to repeated wet conditions due to rainwater, tread pressure from athletes, etc. The buffering function may be lost due to movement and mutual friction. In addition, in the invention of Utility Model Application Publication No. 57-128608, which was developed earlier by the present applicant,
The problem of the sand compacting over time is solved by mixing granules with rubber elasticity, such as rubber chips or crushed pieces of foamed plastic, into the sand.

[Purpose of the invention]

In view of the above-mentioned circumstances, the present invention is suitable for athletic fields where ball bounce performance is not so strictly required, such as soccer fields, rugby fields, or golf course walking paths, and which also has problems with compaction over time in the sand layer. The purpose of this project is to provide an earthen athletic field with sand-filled artificial turf that solves the problem.

[Specific measures]

In order to achieve the above object, the sand-filled artificial turf earthen athletic field according to the present invention is provided with a sand-filled artificial turf made by filling dry sand into the turf of an artificial turf laid on a substantially flat base. In the earthen sports stadium, the dry sand is based on the JIS standard (Z8801-1982
) is characterized by being distributed within a particle size range of two levels, upper and lower, based on the standard sieve nominal size specified in (1).

For the sake of explanation, we will use the “
A part of the "Standard Sieve Nominal Dimensions" is reproduced in the table below.

- (Table 1) - -Table 2- Referring to the above table, the "sand distributed within the particle size range of two levels, upper and lower, based on the nominal size of a standard sieve" used in the present invention will be explained in detail, for example. , the standard particle size was set to 0.6 mm (
600μm), two levels above and below it, i.e. 8
Particles having a size that passes through a 50 μm sieve but remain on a 424 μm sieve are used. In addition, when the standard particle size is 2.0 mm, the nominal sieve size is
2゜0III11'' is the standard, and passes through two levels above and below, that is, 2.80 mm, but 1.40 mm.
Use sand with a particle size within the range that will remain on the sieve mesh. Incidentally, if the grain size range of the sand commonly used in the known artificial turf earthen sports stadiums mentioned above is expressed according to the above method, it will be 100 (μm) to 1.7<mm), which means that there are 19 levels. There will be a difference between Therefore, as shown in the experimental results later, relatively small-diameter particles are filled into the gaps formed between relatively large-diameter particles, which suppresses the movement of each particle. It will be further compacted due to the infiltration of rainwater.

Note that "sand" usually has a particle size of 1/16 mm to about 3 mm.
Since there are particles within this range, the maximum particle size of the sand used in the present invention is naturally limited to this range.

Although any known artificial lawn can be used in the present invention,
Polyamide, polyethylene terephthalate, polyurethane, and polyvinylidene chloride are more similar to natural grass in terms of appearance and texture, and in terms of physical and mechanical properties such as set resistance, tensile strength, tear strength, and weather resistance. ,
Either slit yarn obtained by cutting a film such as polypropylene into thin pieces is used as pile yarn, or flat yarn is made by melt spinning through a nozzle having irregularly shaped cross-sectional holes, and this is used as pile yarn, and these pile yarns are flocked onto the backing base fabric. A formed water-permeable or water-impermeable structure is preferred. The length of the pile threads that make up the grass is 81II11 to 40m.
The above-mentioned dry sand is filled into the grass grains so that the tips of the grass leaves protrude by about 15 mm. Note that this filling ratio of dry sand is a guideline for a state in which the sand is almost stable after being filled into the grass grain. Alternatively, the artificial lawn may be fixed to a substantially flat base using adhesive or stakes, or simply fixed onto the base using the weight of the sand filled within the turf grains. It can be left as a place.

[Action/Effect]

As described in detail above, the sand-containing artificial turf earthen athletic field according to the present invention is based on the JIS standard, in which the dry sand filled in the grains of the artificial turf has a particle size of about 0.6 or more. Standard (Z
8801-1982) to be distributed within the particle size range of two levels, upper and lower, in accordance with the standard sieve nominal size specified in
In other words, compared to the sand used in conventional artificial turf earthen athletic fields, dry sand with a larger diameter and a narrower particle size distribution range is used. As mentioned earlier, sand filled in the grass grains has a so-called "fine structure" in which relatively small-diameter sand particles fit into the gaps between relatively large-diameter sand particles (see Figure 3). ,
In the present invention, sand with a relatively narrow particle size distribution range, so-called "uniform grain" sand, is used to create a "coarse and dense structure" (see Figure 1), and appropriate voids are secured between each particle of sand. Each sand particle moves relatively freely and is not compacted over time due to repeated wet conditions due to rainwater or pressure from the player's foot, and can maintain the free fluidity for a long period of time. The effect of maintaining the free-flowing property or preventing compaction of the sand in the present invention is clarified by experimental data shown in the following examples.

(Example) Examples of the present invention will be described in detail below.

(Example-1) FIG. 1 is a partially enlarged sectional view of the surface layer of a sand-containing artificial turf earthen sports field according to an example of the present invention.

The surface layer of the stadium in this example is formed by planting pile threads (Z) made of polypropylene with a length of about 30 mm on a base fabric (3), and is laid on a substantially flat base (G). from a water-permeable artificial lawn Tl) and dry sand (4) filled in the grass grain of the lawn (1) to a thickness of about 70% of the length of the pile yarn (Z), that is, about 21 mm. Become.

The dry sand (4) is based on a particle size of 0.61, and the "standard sieve nominal size" according to the JIS standard mentioned above is 850 μm.
A particle having a particle size distribution that passes through a sieve of 425 μm and remains on the sieve of 425 μm is used. The fluidity and compaction prevention effect of the dry sand (4) in this example was confirmed by the following experiment, and the experimental results are shown in Figure 2.
Indicated by curve (A).

■Experiment method: First, a circular shape with an inner diameter of 60 mm, a depth of 40 mm, and a wall thickness of 8 mm was prepared according to the "Method for measuring the maximum and minimum density of sand" specified in the "Soil Testing Method" published by the 9D Society of Soil Engineering. The dry sand used in this example was placed in a container, and the container was hit 1000 times with a mallet to compact the sand.

Next, a cylindrical indenter with a diameter of 2 cm was pushed into the dry sand using a penetration testing device, and the correlation between compressive force and penetration depth was observed.

■Experimental results: Comparing the curve (A) in Figure 2 showing the above experimental results with the curve (C) showing the experimental results for the comparative example described later,
The rate of increase in compressive force with increasing blind depth of the indenter in the sand of this example is clearly smaller.

<Example-2> “Sand” was placed in the grass grain of an artificial lawn (1) similar to Example-1.
2.0 mm (nominal sieve size - 2.0 mm), which is close to the maximum particle size of
Based on 0), a sand-filled artificial turf earthen athletic field is created by passing through a sieve with a nominal size of 2.80 mm and filling the remaining dry sand (4) on the sieve with the same size of 1.40 mm. was constructed.

The same experiment as in the previous example was conducted for the dry sand (4) used in this example, and the results are shown by curve (B) in FIG. As is clear from this experimental result, the rate of increase in compressive force with respect to the increase in indenter penetration depth in this example is:
It is much smaller and slower than those of the previous example (see curve A) and the comparative example (curve C).

<Comparative Example> In order to clarify the effect of the present invention by comparing it with that of a known sand-containing artificial turf earthen athletic field, dry sand ( 4) Passes through a 1.70 mm sieve and has a diameter of 100 μm
When we selected the particles with a particle size distribution that remained on the sieve mesh and conducted the same experiment as in the example, we found that as shown in the curve (C) in Figure 2, compared with those of Example 1 and the same 2 The compressive force increases rapidly as the indenter penetrates deeper. This means that the sand remains tightly compacted.

Of course, such a "fine structure" is necessary in the case of a playing field where ball bounce performance is strictly required, such as a tennis court, so it cannot be said to be a drawback in general. It cannot be denied that there is a possibility of excessive compaction at a relatively early stage due to repeated wet conditions due to tread pressure and rainwater.

〔Effect of the invention〕

As detailed above, the present invention is suitable for athletic fields where ball bounce performance is not so strictly required, such as soccer fields, rugby fields, and golf course walking paths.
Moreover, it is possible to provide an earthen athletic field with sand-containing artificial turf that solves the problem of compaction over time in the sand layer.

[Brief explanation of drawings]

FIG. 1 is a partially enlarged sectional view of a sand-containing artificial turf earthen athletic field according to an embodiment of the present invention, and FIG. 2 is a graph showing experimental results regarding the compaction prevention effect of the embodiment of the present invention and a comparative example. , FIG. 3 is a schematic diagram showing the density state of the sand layer in a conventional sports stadium. The meanings of the symbols in the figure are as follows. □■=Artificial grass, 2: Pile yarn, 3: Base fabric, 4;
Dry sand, G: base.

Claims (1)

[Claims] (1) In a sand-containing artificial turf earthen athletic field formed by filling dry sand into the turf of an artificial turf laid on a substantially flat base, the dry sand has a grain size of about 0.6 or more. An athletic field made of sand-containing artificial turf, characterized in that the grain size is distributed within two levels, upper and lower, based on the standard sieve nominal size specified in the JIS standard (Z8801-1982).