JPS6140834Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a floor structure for a judo hall that is not only safe and durable, but also inexpensive and has a wide range of adaptability. Conventionally, the floor of a judo hall has generally been constructed by simply placing judo straw tatami mats made of compressed and sewn straw on a rigid floor such as board or concrete. However, although the floor of a judo hall with this structure is strong, it has poor cushioning properties, and as a result, it has flaws in terms of safety, such as the pain felt by the human body when performing Ukemi, etc., and the possibility of injury. Ta. As a means to improve this and reduce the impact that the human body receives, some methods have been used, for example, to use a spring floor as the floor and to place judo straw tatami mats on the spring floor. However, this structure not only requires a large amount of equipment cost for the spring floor device, but once it is installed, it is difficult to convert it to another playground, and it is impossible to install it in an existing dojo due to the structure under the floor. There are many cases. Recently, as a new attempt to improve the above-mentioned problems in the floor structure of judo halls, as disclosed in the specification of Publication of Utility Model Publication No. 47-3461, a so-called bullet substrate made by bonding a polystyrene board to a urethane foam board was first laid on the floor. A method was proposed in which judo straw mats were spread over the bullet board. However, the urethane foam interposed in the bullet substrate inherently has high flexibility. Therefore, if the urethane foam layer in the board is a thin layer, simply placing judo straw tatami on top of the board will cause the layer to be extremely compressed, making its shock absorption ability almost impossible. Become something. In addition, as a result of this, the impact applied to the Styrofoam board becomes excessive, so the Styrofoam board, which is a brittle material with generally low recovery properties, is easily deformed, cracked, and crumbled. The tatami mats in the center of the dojo, where the height is high, tend to sink, sag, and dent, creating a difference in level between the tatami mats and the surrounding tatami mats. This is extremely dangerous when performing movements commonly used in judo, such as suriashi leg feeds or foot sweep techniques. In addition, if the urethane foam in the board is a thick layer, for example, even if the butt lines between the bullet boards and the butt lines between the tatami mats do not match, the urethane foam's original flexibility will be affected. As a result, the floor vibrates violently as a result of the movement, which tends to cause instantaneous differences in level between the tatami mats. Moreover, this idea was difficult due to the complexity of processing, which requires joining two types of foam, and the necessity of arranging the mats so that the butt lines between the bullet boards and the butt lines between the tatami mats do not match. This also has its drawbacks. The purpose of this invention is to provide a floor structure for a judo hall that has excellent safety and durability, has little floor shaking caused by exercise, does not create a step between the tatami mats, and has good shock absorption capacity. do. The second purpose of the present invention is that it is suitable for both plank floors, concrete floors, and those with or without springs installed, and is suitable for not only new construction but also remodeling of existing facilities and temporary construction using other venues. It is easy to process and install, and is inexpensive.
The purpose of the present invention is to provide a highly safe floor structure for a judo hall. In other words, the present invention is based on the optimum stress value of the dynamic impact characteristic curve obtained in accordance with the ASTMD1596-69T method.
Judo is a polyolefin foam that is within the range of 0.04 to 0.15Kg/ ^cm2 , has a minimum impact value of 50G or less, and has a repeated compression residual strain value of 10% or less obtained in accordance with JISK6767 method. The gist of this is a floor structure for a judo hall, which is laid on the floor of the hall, and straw tatami mats for judo are placed on the upper surface of the foam. The present invention will be explained below with reference to the accompanying drawings. FIG. 1 is a graph illustrating the range of dynamic impact characteristics that the polyolefin foam used as the underlay of straw tatami mats for judo in the present invention should have. The polyolefin foam selected by this invention is
The optimal stress value of the dynamic impact characteristic curve obtained according to the test method for dynamic impact characteristics (full surface compression), which will be described later, was established in accordance with the ASTMD1596-69T method.
It is within the range of 0.04 to 0.15 Kg/cm ² and has a minimum impact value of 50 G or less. Therefore, among the six dynamic impact characteristic curves A, B...E, and F illustrated in FIG.
The polyolefin foam of C satisfies the conditions of the present invention. The polyolefin foam used in the present invention satisfies the above conditions and has a repeated compression residual strain of 10% or less as measured in accordance with the test method described below, which was formulated in accordance with the method of JISK6767. The selection of polyolefin foam, which has the above-mentioned properties, as a buffering medium between the floor and straw tatami mats for judo is essential for the present invention to achieve the above-mentioned purpose of the floor structure of a judo hall. It is a requirement. In other words, by laying a polyolefin foam that has the above characteristics at the bottom of straw tatami mats for judo, the vibration of the floor caused by movement on the tatami mats can be suppressed to a range suitable for judo, and the passive movement of the athlete can be suppressed. It is possible to obtain an excellent floor structure for a judo hall that absorbs the severe impact caused by such events into the foam, alleviating the pain felt by the human body, and that does not create a momentary difference in level between the tatami mats, and is also durable. It becomes possible for the first time. Here, the optimum stress value for polyolefin foam is
If it is less than 0.04 Kg/cm ² , for example, as shown in curve 2 in FIG. 1, it is unavoidable that a difference in level between the tatami mats will occur due to the impact caused by the movement on the tatami mat due to its low compressive strength. On the other hand, this value is, for example, 0.15 as shown in the curve in Figure 1.
If it exceeds Kg/cm ² , the cushioning properties of the foam are insufficient in proportion to its high compressive strength, and the pain experienced by the human body during passive activities cannot be alleviated. Additionally, the minimum impact value of polyolefin foam is
For example, when the load exceeds 50G, such as curve E in Figure 1, the shock absorption capacity is not much different from that of straw tatami mats for judo, so polyolefin foam is used as the cushioning medium. We cannot expect an increase in shock absorption capacity due to this. Repeated compression residual strain of polyolefin foam
It is also important that it is 10% or less. If a polyolefin foam with this value exceeding 10% is used, the foam is likely to lose its thickness over time, so-called sagging, depending on the frequency of use at the judo hall, and due to this, the frequency of use may be reduced. It cannot withstand long-term use because there is a difference in level between the different tatami mats. As shown in FIG. 3, the present invention has a simple structure in which polyolefin foam 1 and judo straw tatami mats 3 are stacked on a floor 2 made of board or concrete. In addition, 4 in the figure indicates a frame that fixes the foam 1 and the tatami mat 3 around them in order to prevent them from shifting. However, even with such a simple structure, if the polyolefin foam used therein is selected from a certain range, it is surprisingly safe and durable, making it an extremely ideal judo product. Configure the floor of the venue. The present invention focused on this point, which no one had ever predicted before, and succeeded in elucidating it. The simple property of the floor structure of the present invention is extremely important in the present invention. The superior judo hall floor structure obtained through the use of specific polyolefin foams has increased flexibility due to its simplicity. The floor structure of the present invention is suitable for new construction regardless of whether it is a board floor or a concrete floor, and whether or not a spring device is installed. Modification of existing facilities is also easy.
In addition, it is easy to temporarily set up a judo hall either indoors or outdoors, and it is also easy to remove and restore it. Moreover, commercially available plates of polyolefin foams are easily available, almost no processing is required, and construction is simple and can be carried out satisfactorily even by an amateur. Therefore, the cost is also low. The polyolefin foam used in this invention is 20 to 80
It is preferable to use a thickness in the range of mm. If possible, it is wise to use a commercially available board that falls within the above thickness range. Further, the larger the area, the better, but from the viewpoint of ease of installation and portability, 2000 to 2600 mm in height x 500 to 600 mm in width is appropriate. Next, various test methods used in the present invention are listed. 1 Dynamic impact properties (full surface compression) According to the dynamic compression test method for packaging cushioning materials ASTMD1596-69T, weights of the same weight were dropped 5 times in a row at 1-minute intervals, excluding the 1st time and 4 times from 2nd to 5th times. Find and record the average of the measured impact values of
Further, measurements were taken while changing the weight of the weight, and the dynamic impact characteristic curve/impact value-static stress shown in Figure 1 was drawn. Optimum stress and minimum impact value The lowest impact value on the dynamic impact characteristic curve shown in Figure 1 - impact value - static stress curve is called the minimum impact value, and the static stress value that gives this minimum impact value is the optimum value. It's called stress. Test conditions Weight drop height 60cm Sample thickness 5cm 2 Repeated compression residual strain According to the JISK6767 Repeated Compression Residual Strain Test Method for Polyethylene Foam, the ratio of the difference in thickness before and after the test is the residual strain. Sample size is 50 x 50 x thickness approx. 25mm, 25%
Compression is performed 80,000 times (60 times/min) and the thickness is measured after being left for 24 hours. Repeated compression residual strain = T ₁ - T ₂ /T x 100 (%) where T ₁ : Initial thickness T ₂ : Thickness after test 3 Dynamic impact properties (local compression) ASTMD1596-69T of packaging cushioning material According to the dynamic compression test method, the cylindrical dummy (area
129cm ² ), a local compression drop test was performed, and the dynamic impact characteristic curve and impact value shown in Figure 2 were obtained.
Find static stress. Test conditions: Height of drop of cylindrical dummy: 60cm Thickness of sample: Detailed in Examples 1 and 2 Comparative Example 1 Examples 1 and 2 Comparative Example 1 Judo placed on a wooden floor, which is typical of the conventional judo hall floor structure. Using straw tatami as a comparative example, the floor structure of the present invention has a polyethylene foam board interposed between the floor and the tatami that has the dynamic impact characteristics of curve B shown in Figure 1 and has a repeated compression residual strain of 5%. As an example, the dynamic impact characteristic curves (partial compression) of each were determined. Figure 2 shows a cylindrical dummy simulating a human head according to the test method listed above in the main text of the specification.
The test results were obtained by dropping different weights from a height of 60 cm, performing the test five times for each weight, excluding the first measurement value, and blotting the average value of the second to fifth measurements. In the figure, curved line G is Comparative Example 1 in which judo straw tatami mats were placed on the floor, curved line G is Example 1 in which a 25.9 mm thick polyethylene foam board was interposed between the floor and the tatami mats, and curved line G is Example 1. Example 2 where the foam board of 1 was made 53.1mm thick
It is. The judo straw tatami mats used in the Examples and Comparative Examples were general-purpose products with a thickness of 62.6 mm. As is clear from FIG. 2, curves Q and I have lower impact values at all static stress points than curve G. This means that the floor structure of the example, which resulted in curved chips and chips, exhibits better shock absorption ability against all impacts than the floor structure of the comparative example, which resulted in curved chips, and is therefore safer. This clearly shows that it is extremely high. Example 3 Comparative Examples 2 to 9 Five Judo players with 3rd Dan or higher were commissioned to evaluate the safety, durability, workability, construction efficiency, cost, and adaptability of various floor structures for Judo halls. The items were evaluated and their comprehensive evaluation was conducted. This is shown in Table 1. The following nine types of floor structures were targeted. Example 3: A 50 mm thick polyester foam according to the present invention, which has the dynamic impact characteristics of curve C in Figure 1 and a 10% repeated compression residual strain, is laid on a wooden floor, and a judo foam is placed on top of it. A 60 mm thick straw tatami mat was placed on it. Comparative Example 2: A 50 mm thick polyethylene foam having the dynamic impact characteristics shown in curve 2 in Figure 1 and a repeated compression residual strain of 7% was laid on the wooden floor. A 60 mm thick straw tatami mat for judo was placed. Comparative Example 3: A 50 mm thick polyethylene foam with dynamic impact characteristics for the curve shown in Figure 1 and a repeated compression residual strain of 5% was placed on a wooden floor. A 60 mm thick straw tatami mat for judo is placed on top.Comparative example: A 50 mm thick polyethylene foam with the dynamic impact characteristics of curve E in Figure 1 and a repeated compression residual strain of 7% is placed on the wooden floor. A 60 mm thick straw tatami mat for judo is placed on top of it. Comparative Example 5: A 50 mm thick polyethylene foam with dynamic impact characteristics similar to curve C in Figure 1 but with a repeated compressive residual strain of 15% is placed on the wooden floor. Comparative example 6: 60 mm thick straw tatami for judo is laid on a wooden floor with built-in springs. Comparative example 7: Judo straw tatami is placed on a wooden floor. Lay 60mm thick tatami mats Comparative Example 8: Lay synthetic judo tatami made of 30mm thick judo straw tatami and 30mm thick polyurethane foam on a wooden floor Comparative Example 9: Lay polystyrene foam on a wooden floor A bullet board made of 25mm thick polyurethane foam and polyurethane foam is laid with the polystyrene side facing up, and on top of that, a judo mat is placed so that the butt lines between the bullet boards and judo straw tatami mats do not match. Placing straw tatami mats The evaluation criteria are as follows: 〇 means good, △ means good, and × means bad.

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[Table] As shown in the evaluation table in Table 1, the structure of Example 3 of the present invention had no drawbacks in all of the six evaluation items necessary for a floor structure for a judo hall. Among Comparative Examples 2 to 9, only Comparative Example 6, which had a so-called spring bed structure, received a good rating in the particularly important safety aspect. However, considering that Comparative Example 6 also has drawbacks in workability, cost, and adaptability, it could not be judged as being good overall. Since the floor structure of the judo hall of the present invention has the above-mentioned configuration, the pain felt by the human body during, for example, Ukemi is alleviated, and the structure does not deform or break over a long period of time, and the level difference between the tatami mats can be reduced. It is possible to maintain an extremely high level of safety without causing any problems. In addition, the floor structure of the present invention can be constructed at a low cost by simple construction, so it is easy to construct a new dojo, improve an existing dojo, or construct a temporary dojo using another athletic field, venue, or outdoors. All in all, its usefulness is extremely high.

[Brief explanation of the drawing]

FIG. 1 is a graph illustrating a dynamic impact curve of a polyolefin foam. Figure 2 is a graph illustrating the dynamic impact curve of a judo hall floor. FIG. 3 is a front cross-sectional view of the judo hall floor structure of the present invention. 1... Polyolefin foam, 2... Floor, 3...
... Straw tatami mats for judo halls, 4... Frame, 5... Butt lines between foams, 6... Butt lines between tatami mats.

Claims (1)

[Scope of utility model registration request] The optimum stress value of the dynamic impact characteristic curve obtained in accordance with the ASTM D1596-69T method is within the range of 0.04 to 0.15Kg/ ^cm2 , and the minimum impact value is 50G or less, and in addition, it is in accordance with the JIS K6767 method. A floor structure for a judo hall in which a polyolefin foam having a cyclic compression residual strain value of 10% or less obtained in accordance with the above is laid on the floor of a judo hall, and straw tatami for judo is placed on the top surface of the foam. .