JP7615912B2 - Shock absorbing flooring - Google Patents

Description

The present invention relates to shock-absorbing flooring, which is particularly effective in preventing femoral fractures in the event of a fall.

Falls and fractures among the elderly are currently a social problem, and are the cause of 10% of elderly people becoming dependent on care. In addition, falls and fractures account for 20-25% of medical accidents. The location of fractures caused by falls varies greatly depending on age, with the risk of femoral fractures increasing sharply after the age of 60. Femoral fractures require hospitalization for treatment and can result in the inability to walk for a long period of time, leading to a decrease in bone mass and a more serious condition of the condition, making it more likely that the patient will become dependent on care. In childcare facilities such as kindergartens, nursery schools, and certified childcare centers, accidents caused by falls and fractures account for just over 20% of all accidents.

For this reason, for example, the following Patent Documents 1 and 2 propose flooring materials that reduce the risk of bone fractures by absorbing the shock of a fall.

Patent No. 3600726 Patent No. 5244927

Yasuhiro Nishio et al., Experimental Mechanics, Vol. 16, No. 4, pp. 307-314, 2016 S. N. Robinovitch et al., Journal of Biomechanical Engineering, vol.113, pp.366-374, Nov. 1991 Amy C. Courtney et al., The Journal of Bone and Joint Surgery, vol.77-A, No.3, pp.387-395, Mar. 1995

The performance of the flooring materials described in Patent Documents 1 and 2 is evaluated based on the floor hardness test stipulated in the Japanese Industrial Standard "JIS A 6519," and they are deemed "safe" if the "G value" obtained in the test is 100G or less.

However, because the floor hardness test described above is a repurposed head injury evaluation, it is difficult to say that it is able to properly evaluate the risk of femoral fracture. For this reason, it is difficult to say that the safety evaluation of the above-mentioned conventional flooring materials against femoral fractures is adequately guaranteed, and they do not adequately address the risk of femoral fractures.

In light of this, the present invention aims to provide a shock-absorbing flooring material that can adequately address the risk of femoral fractures.

The shock-absorbing flooring material according to the present invention, which is for solving the above-mentioned problems, is a shock-absorbing flooring material that suppresses fractures of the femur caused by the impact caused by a user's fall, and comprises a flooring material made of a hard material, a flooring base material made of a soft material provided below the flooring material, and a compressed air container (air cushion layer), and is characterized in that the bending rigidity value of the flooring material over a width of 10 mm of the flooring material is 1 ^Nm2 or more and 200 ^Nm2 or less, and an impact-applying body having a weight and shape based on the pressure distribution applied to the trochanter of the femur when the user falls is dropped from a drop height based on the height of the user's waist, and an impact is applied to a cushioning material made of a material simulating human soft tissue under conditions set so that the standard impact load Fs generated when the impact-applying body is dropped from the drop height and an impact is applied to the flooring material via the cushioning material is 2000 N or more and 5000 N or less.

The impact-absorbing flooring material of the present invention provides good walkability and adequately addresses the risk of femoral fractures in the event of a fall, ensuring a reduction in the incidence of falls and fractures that can lead to the elderly needing care and causing medical accidents.

1 is a schematic structural diagram of a main embodiment of an impact absorbing floor material according to the present invention. 1 is a schematic structural diagram of a main part of a main embodiment of an impact load measuring device for measuring the impact load of an impact absorbing floor material according to the present invention. 10 is a schematic structural diagram of a main part of another embodiment of an impact load measuring device for measuring the impact load of an impact absorbing floor material according to the present invention. FIG. 13 is a schematic structural diagram of a main part of still another embodiment of an impact load measuring device for measuring the impact load of an impact absorbing floor material according to the present invention. FIG. 13 is a schematic structural diagram of a main part of still another embodiment of an impact load measuring device for measuring the impact load of an impact absorbing floor material according to the present invention. FIG. 10 is a schematic structural diagram of another embodiment of the weight of the impact load measuring device for measuring the impact load of the impact absorbing floor material according to the present invention. FIG. 13 is a schematic structural diagram of yet another embodiment of the weight of the impact load measuring device for measuring the impact load of the impact absorbing floor material according to the present invention. FIG.

The following describes an embodiment of the impact absorbing flooring material according to the present invention, but the present invention is not limited to the following embodiment described with reference to the drawings.

[Main embodiment]
A main embodiment of the impact absorbing floor material according to the present invention will be described with reference to Figs.

As shown in FIG. 1, the shock-absorbing flooring material according to this embodiment is a shock-absorbing flooring material 110 that prevents fractures of the femur caused by the shock of the user falling, and includes an upper flooring material 111 made of a hard material, a flooring base material 112 made of a soft material provided below the upper flooring material 111, an air cushion layer 115, a safety valve 116 that releases air at a predetermined pressure, a pattern layer 113 laid on the upper surface of the upper flooring material 111, and a protective layer 114 laid on the upper surface of the pattern layer 113.

The flooring material 111 is made of a hard material such as a wood base material such as plywood, a composite base material made of a mixture of wood powder and plastic, or a resin base material such as polyolefins such as polyethylene (PE) or polypropylene (PP) or polyvinyl chloride (PVC), and forms the floor surface on which users walk.

The floor underlayment 112 is made of soft materials such as resins such as polyolefin, PVC, ethylene vinyl acetate copolymer (EVA), polystyrene (PS), polyurethane (PU), etc., and has a foam structure such as closed or open foam formed by methods such as chemical foaming, physical foaming, and supercritical foaming, and constitutes an impact absorbing section that absorbs impacts.

The pattern layer 113 is a sheet made of the same material as the floor covering 111, such as polyolefin or PVC, with a pattern such as wood grain or a geometric pattern applied to it, which adds a design element and is provided as needed.

The protective layer 114 is made of an acrylic coating, transparent PVC, or the like, and protects the surface to improve durability such as chemical resistance, scratch resistance, and dent resistance, and is provided as needed.

The air cushion layer 115 is made of PVC, PE, etc., and can withstand pressures of 20 to 50 MPa. A safety valve 116 is attached to the air cushion layer, and when an impact is applied to the impact absorbing flooring material 110 and a certain load is applied, air flows out from the safety valve when the internal pressure exceeds the set pressure of the safety valve due to the increase in pressure. Therefore, when an impact occurs, a period of time occurs during which deformation occurs at a constant load corresponding to the set pressure of the safety valve, making it possible to suppress or control the impact load.

The floor covering 111 has a bending stiffness (bending stiffness) value of 1 ^Nm2 or more and 200 Nm2 or ^less in a width of 10 mm.

If the measured value of the bending stiffness (bending stiffness) per unit width of the floor covering 111 is less than ¹ Nm2, the floor covering is likely to bend and become locally compressed, and the floor covering will sink when walking, impairing the walking feel, which is not preferable. From the viewpoint of the walking feel, it is preferable that the bending stiffness is at least 10 ^Nm2 or more. Also, if the measured value exceeds 200 ^Nm2 , it is not preferable because the workability is likely to be poor due to bulkiness, etc.

The bending stiffness (bending stiffness) value of the flooring material 111 per unit width is a value calculated from the product (EI) of Young's modulus E (bending elasticity) and area second moment I obtained by a three-point bending test. If the flooring material 111 is made of a composite material in which multiple materials with different hardness are laminated, it can be obtained by calculating the product (EI) of Young's modulus E (bending elasticity) and area second moment I for each layer of material, and then calculating the sum of these.

The thickness of the floor underlayment 112 is designed based on the impact and dynamic compression characteristics of the underlayment, and there is no limit.

The internal pressure of the air cushion layer is desirably as high as possible from the standpoint of walkability, i.e., ease of walking without sinking, and it is desirable to set the product of the impact load to 2000N or more. In addition, by providing a safety valve that leaks at a specified pressure when a load of 2000 to 5000N is applied to the impact absorbing material, it is possible to gradually reduce the energy applied to the underfloor material at the time of impact and suppress the maximum impact load.

The shock-absorbing flooring 110 is designed such that an impact-applying body having a weight and shape based on the pressure distribution applied to the trochanter of the femur when the user falls is dropped from a drop height based on the height of the user's waist, and the standard impact load Fs generated when the impact is applied to a cushioning material made of a material simulating human soft tissue is set to 6500 N. When the impact-applying body is dropped from the drop height and an impact is applied to the flooring 110 through the cushioning material, the impact load F generated is 2000 N to 5000 N (preferably 3440 N or less). A load of 3440 N or less can sufficiently reduce the risk of fracture.

Here, the impact load measuring device for measuring the impact load F and the amount of displacement (deformation) D is shown in FIG.
The explanation will be based on the above.

As shown in FIG. 2, the impact load measuring device 2 comprises a measurement table 5 installed on the floor FL, a weight drop unit 6 arranged on the measurement table 5, and a load measuring unit 7. A load cell 8 of the load measuring unit 7 is arranged on the measurement table 5, and an evaluation floor material 9 made of the same material as the shock absorbing floor material 110 to be evaluated for safety against fractures is placed on the load cell 8, and a cushioning material 10 is placed on the evaluation floor material 9. The load cell 8 receives the impact load when the impact applying body, weight 11, falls, and outputs the information to an impact load calculation device 12.

The weight drop section 6 is equipped with a support 13 that rises from the measurement table 5, an arm 14 that extends horizontally perpendicular to the top of the support 13, and a height adjustment section 15 such as a dial that changes the height of the arm 14 relative to the support 13. An electromagnet 16 is disposed at the bottom of the tip side of the arm 14, and when an electromagnet ON/OFF device 17 is turned ON, the weight 11 equipped with an accelerometer 18 is attracted to the electromagnet 16, and when the electromagnet ON/OFF device 17 is turned OFF, the weight 11 is separated from the electromagnet 16 together with the accelerometer 18, and the weight 11 drops onto the cushioning material 10 together with the accelerometer 18.

The accelerometer 18 outputs the information to the impact energy and displacement amount calculation device 19. Based on the information from the accelerometer 18, the impact energy and displacement amount calculation device 19 calculates the impact energy SE caused by the collision of the weight 11 and calculates the displacement (deformation) D of the floor underlayment of the evaluation floor material 9. In this embodiment, the weight drop part 6, the electromagnet 16, and the electromagnet ON/OFF device 17 correspond to the weight holding and dropping part.

The impact part 11a on the lower surface of the weight 11, which comes into contact with the cushioning material 10 and strikes it, has a curved surface with a radius of curvature R of 60 mm to 180 mm (preferably 90 mm to 160 mm) that mimics the shape of the trochanter of the femur, and is spherical overall.

The cushioning material 10 is made of an ultra-soft polyurethane resin for modeling that mimics the soft tissue of the human body (for example, "Human Skin Gel" (product name) manufactured by Exseal Co., Ltd.), and mimics the soft tissue of the human body around the femur. The Asker C hardness (based on the Japanese Industrial Standard "JIS K 7312") is greater than 0 and less than 16 (preferably 5 to 10), the Young's modulus is 0.05 MPa to 0.8 MPa (preferably 0.1 MPa to 0.5 MPa), the dynamic viscoelasticity Tan δ (based on the above-mentioned non-patent document 1) at 25°C and a measurement frequency of 1 Hz is 0.1 to 0.7 (preferably 0.2 to 0.5), and the thickness is 7 mm to 80 mm (preferably 9 mm to 30 mm).

The method for measuring the impact load F and the amount of displacement (deformation) D using this type of impact load measuring device 2 will now be described.

First, the height adjustment unit 15 is operated so that the arm 14 of the weight drop unit 6 of the impact load measuring device 2 is set to the drop height Sh of the weight 11, and the weight 11 (together with the accelerometer 18, the weight Sw) is prepared. The electromagnet ON/OFF device 17 is turned ON to cause the electromagnet 16 placed on the arm 14 to attract the weight 11 together with the accelerometer 18. The load cell 8 is placed on the measurement table 5, and a cushioning material 10 with a thickness Ka and hardness Kb is placed on the load cell 8.

Then, by turning off the electromagnet ON/OFF device 17, the weight 11 and accelerometer 18 separated from the electromagnet 16 are dropped onto the cushioning material 10. The impact load calculation device 12 calculates the reference impact load Fs based on the impact load value from the load cell 8, while the impact energy/displacement calculation device 19 calculates the displacement (deformation) D1 of the cushioning material 10 caused by the collision of the weight 11 based on information from the accelerometer 18, and calculates the impact energy SE based on the information from the accelerometer 18, the weight Sw, the drop height Sh, etc.

When the standard impact load Fs is 6500N and the impact energy SE is 28.4J, the conditions such as the drop height Sh and weight Sw of the weight 11, the thickness Ka and hardness Kb of the cushioning material 10 are set as they are, and when the standard impact load Fs is not 6500N or the impact energy SE is not 28.4J, the above conditions are appropriately adjusted so that the standard impact load Fs is 6500N and the impact energy SE is 28.4J, thereby setting the standard impact load Fs of the impact load measuring device 2 to 6500N and the impact energy SE to 28.4J.

The standard impact load Fs is set to 6500 N by multiplying it by 1.15 as a safety factor, since an impact force of 5600 N (in a state of muscle relaxation) is applied to the femur when falling from a standing position (see Non-Patent Document 2). The impact energy SE is a value that is calculated and determined in advance based on the value of the standard impact load Fs and the conditions of the cushioning material 10 (such as thickness and various physical properties), and is often set to 28.4 J.

After setting the standard impact load Fs and impact energy SE of the impact load measuring device 2, the evaluation floor material 9 is placed between the load cell 8 and the cushioning material 10, and the electromagnet ON/OFF device 17 is turned OFF again to drop the weight 11, which has been detached from the electromagnet 16, onto the cushioning material 10 together with the accelerometer 18. The impact load calculation device 12 calculates the impact load F based on the impact load value from the load cell 8, and the impact energy/displacement calculation device 19 calculates the combined displacement (deformation) D2 of the cushioning material 10 and the evaluation floor material 9 caused by the collision of the weight 11 based on information from the accelerometer 18. The difference (D2-D1) between this and the previously calculated displacement (deformation) D1 of the cushioning material 10 is calculated to calculate the displacement (deformation) D of the floor underlayment of the evaluation floor material 9.

If the impact load F thus calculated is less than 2000N, the shock absorbing capacity will be too strong, making walking difficult, which is undesirable, and if it exceeds 5000N, the shock absorbing capacity will be too weak, making it difficult to adequately address the risk of femoral fracture, which is undesirable.

Therefore, the shock-absorbing flooring material 110 according to this embodiment can adequately address the risk of femoral fractures, and can reliably reduce the incidence of falls and fractures that can lead to elderly people needing care and medical accidents.

[Other embodiments]
<Impact load measuring device>
In the above-described embodiment, the impact load F is measured using the impact load measuring device 2 as shown in FIG. 2. However, the present invention is not limited to this. As another embodiment, for example, the impact load F can be measured using an impact load measuring device as shown in FIGS. 3 to 5.

Specifically, in the impact load measuring device 30 shown in FIG. 3, the evaluation floor material 9 is placed on the measurement table 5, and the cushioning material 10 is placed on the evaluation floor material 9. The weight 11, accelerometer 18, and load cell 8 are integrated to form an impact applying body, and the weight 11, accelerometer 18, and load cell 8 together form a weight Sw. Then, when the electromagnet ON/OFF device 17 is turned ON, the weight 11, accelerometer 18, and load cell 8 are attracted and held by the electromagnet 16.

The weight 11 has a cylindrical shape as a whole, with only the impact part 11a on the lower surface that comes into contact with the cushioning material 10 and delivers an impact, and has a curved surface with a radius of curvature R of 60 mm to 180 mm (preferably 90 mm to 160 mm) that mimics the shape of the trochanter of the femur.

In this type of impact load measuring device 30, as in the case of the above-mentioned embodiment, by turning off the electromagnet ON/OFF device 17, the weight 11 can be detached from the electromagnet 16 together with the accelerometer 18 and the load cell 8, and dropped onto the cushioning material 10.

In the impact load measuring device 31 shown in FIG. 4, the evaluation floor material 9 is placed on the measurement table 5, and the cushioning material 10 is placed on the evaluation floor material 9. The weight drop part 6 is structured so that the arm 14 can swing downward around the height adjustment part 15. The accelerometer 18 and load cell 8 are fixed to the tip of the arm 14, and the weight 11 is also fixed to it. In this embodiment, the weight drop part 6 corresponds to the weight holding and dropping part, the height adjustment part 15 corresponds to the rotating part, and the weight 11, accelerometer 18, load cell 8, and arm 14 correspond to the impact applying body.

In this type of impact load measuring device 31, the arm 14 of the weight drop unit 6 is adjusted to the drop height Sh of the weight 11 by operating the height adjustment unit 15 of the impact load measuring device 31. Then, the height adjustment unit 15 is loosened to swing the arm 14 downward, allowing the weight 11 to drop onto the cushioning material 10.

In the impact load measuring device 32 shown in FIG. 5, the floor material laid on the existing floor FL is the evaluation floor material 9. The weight drop section 6 of this impact load measuring device 32 is also structured so that the arm 14 can swing downward around the height adjustment section 15. An accelerometer 18 and a load cell 8 are fixed to the tip of the arm 14, and further, the weight 11 is fixed, and a cushioning material 10 is arranged to cover the lower part of the weight 11. In this embodiment, the weight 11, the accelerometer 18, the load cell 8, the arm 14, and the cushioning material 10 correspond to the impact applying body.

In this type of impact load measuring device 32, the arm 14 of the weight drop unit 6 is adjusted to the drop height Sh of the weight 11 by operating the height adjustment unit 15 of the impact load measuring device 31. Then, by loosening the height adjustment unit 15 and swinging the arm 14 downward, the weight 11 can be dropped through the cushioning material 10 onto the evaluation floor material 9 laid on the floor FL.

<Impact Applicator>
In addition, in the above-mentioned embodiment, a spherical or cylindrical weight 11 having a curved surface with a radius of curvature R of 60 mm or more and 180 mm or less (preferably 90 mm or more and 160 mm or less) is applied so that the impact portion 11a on the lower surface that comes into contact with the cushioning material 10 to deliver the impact mimics the shape of the trochanter of the femur. However, as another embodiment, for example, as shown in Figure 6, it is more preferable to set the radius of curvature R1 (e.g., 175 mm) in one direction (length direction) of the impact portion 11a on the lower surface that comes into contact with the cushioning material 10 to deliver the impact and the radius of curvature R2 (e.g., 65 mm) in the other direction (width direction) perpendicular to the one direction separately, thereby making the impact portion 11a into a weight 11 that further approximates in three dimensions the shape of the trochanter of the femur.

In the above embodiment, the impactor is described as having a striking portion 11a integrally formed with the weight 11. However, the present invention is not limited to this. For example, as shown in FIG. 7, it is also possible to provide an impactor in which the weight 11 is divided into a heavy main body portion 11b and a striking portion 11a that strikes the impact, and a load cell 8, an accelerometer 18, or the like is interposed between the main body portion 11b and the striking portion 11a.

<Load measurement section>
In the above-described embodiment, the impact load is measured directly by utilizing the load cell 8. However, in another embodiment, instead of the load cell 8, it is also possible to obtain the impact load based on, for example, the acceleration measured by the accelerometer 18.

<Cushioning material>
In addition, in the above-described embodiment, the application of the cushioning material 10 made of ultra-soft urethane resin for molding was described, but depending on the conditions, it is also possible to apply cushioning materials made of synthetic rubber, natural rubber and its foams, polystyrene foam, various elastomers and their foams, animal soft tissue, etc.

Ultra-soft polyurethane resin for modeling is highly suitable because it is not only consistent as a material, but also behaves similarly to the soft tissues of the human body, and therefore has a wide range of applicable conditions for the above-mentioned measurement method using the impact load measuring device 2, and is highly versatile as a cushioning material for measuring impact loads caused by falls under various conditions.

The following describes examples that were conducted to confirm the effectiveness of the impact-absorbing flooring material of the present invention, but the present invention is not limited to the examples described below.

[Test specimen]
Test specimens of Examples 1 to 5 and Comparative Examples 1 to 4 of floor covering materials and under-floor materials, and flooring materials consisting of an air cushion layer, shown in Table 1 below, were prepared.

The bending stiffness (bending stiffness) of the flooring material at a width of 10 mm was determined by performing a three-point bending test on a 100 mm x 10 mm test piece with a span of 80 mm to determine Young's modulus E (bending elasticity) and calculating the second moment of area I based on the following formula (1), and then determining it as the product (EI) of the Young's modulus E (bending elasticity) and the second moment of area I.

I=(bh ³ )/12 (1)
Here, b is 1 (unit width) and h is thickness.

[Test Contents]
For the above-mentioned test specimen Examples 1 to 5 and Comparative Examples 1 to 4, the impact load F and the displacement (deformation) D were determined, respectively, using the impact load measuring device 2 described above. However, in the impact load measuring device 2, the weight 11 was divided into a heavy main body portion 11b and a striking portion 11a for applying an impact, as shown in Fig. 7, and a load cell 8 and an accelerometer 18 were interposed between the main body portion 11b and the striking portion 11a to form an impact applying body.

<Device specifications>
・Load cell: "TCLU-5A" (model number) manufactured by Tokyo Measuring Instruments Laboratory Co., Ltd.
- Accelerometer: Showa Sokki Co., Ltd. digital shock and vibration accelerometer "1340B" (model number)
Measurement table/table size: 750mm x 1000mm x 125mm Weight: 185kg
・Main body of weight/Material: Stainless steel ・Striking part of weight/Material: Machined stainless steel Curvature radius R: 100 mm
Impactor/weight Sw: 5.85 kg (including accelerometer)
・Cushioning material: "Human Skin Gel" (product name) manufactured by Exseal Co., Ltd.
Thickness: 20 mm Asker C hardness: 7 Young's modulus: 0.22 MPa
Dynamic viscoelasticity Tan δ: 0.24 (25 ° C, measurement frequency 1 Hz)

<Test Method>
As described in the above embodiment, the weight 11 was dropped (drop height Sh: 50 cm), and the impact loads Fs, F were determined based on the information from the load cell 8, and the displacement of the weight was determined based on the information from the accelerometer.

In addition, the shock absorption performance was evaluated by dividing the load F into the ranks shown in Table 2 below, based on the description in Non-Patent Document 3.

[Test Results]
The results of the above mentioned tests are shown in Table 3 below.

Comments on Examples and Comparative Examples In Example 1, the shock absorption was judged as △ in Table 2, but the walkability was very good and was rated as ◎. Examples 2 and 3 were almost the same, and the shock absorption was judged as △ in Table 2. The walkability was evaluated as ◯, which was slightly inferior to Example 1, but was sufficiently good. In Example 4, the shock absorption was judged as ◯ and the walkability was ◯, both of which were well balanced. In Example 5, the load F rank was the same, but the shock absorption was even better, but the walkability was slightly reduced due to the occurrence of slight sinking. In Comparative Example 1, the shock absorption was in very good condition ◎, but on the other hand, the rigidity of the floor material was insufficient, so the walkability was ×. In Comparative Examples 2 to 4, the air cushion layer was removed from Examples 1 to 3, and the walkability was good ◎, but the shock absorption was ×.

From the above, it has been confirmed that the shock-absorbing flooring material of the present invention can adequately address the risk of femoral fractures.

The shock-absorbing flooring material of the present invention can adequately address the risk of femoral fractures, and can therefore be applied to the floors of a variety of facilities, including nursing homes for the elderly, medical facilities such as hospitals, and childcare facilities such as kindergartens, nursery schools, and certified childcare centers, making it extremely useful in industry.

2, 30 to 32...Impact load measuring device 5...Measuring table 6...Weight dropping section 7...Load measuring section 8...Load cell 9...Evaluation floor material 10...Cushioning material 11...Weight 11a...Striking section 11b...Main body 12...Impact load calculation device 13...Support 14...Arm 15...Height adjustment section 16...Electromagnet 17...Electromagnet ON/OFF device 18...Accelerometer 19...Impact energy/displacement calculation device 110...Impact absorbing floor material 111...Floor top material 112...Floor underlay material 113...Pattern layer 114...Protective layer

Claims (5)

A shock-absorbing flooring material that prevents fractures of the femur caused by the impact of a user falling,
A floor covering made of a hard material;
The floor covering comprises an underfloor material made of a soft material provided below the floor covering, and an air cushion layer having a mechanism for releasing air through a safety valve at a predetermined pressure, the bending rigidity of the floor covering over a 10 mm width of the floor covering is 1 Nm2 or ^more and 200 Nm2 ^or less,
An impact-applying body having a weight and shape based on the pressure distribution applied to the trochanter of the femur when the user falls is dropped from a drop height based on the height of the user's waist, and an impact is applied to a cushioning material made of a material that mimics human soft tissue, under conditions set so that the standard impact load Fs generated when the impact-applying body is dropped from the drop height and an impact is applied to the flooring through the cushioning material, the impact load F generated is 2000N or more and 5000N or less. The air cushion layer according to claim 1,
This shock-absorbing floor material is characterized in that a safety valve is activated to allow air to flow out so that the load applied to the air cushion layer through the upper floor material and the lower floor material is 2000N or more and less than 5000N. The impact absorbing floor material according to claim 1 or 2,
The impact-applying body is provided with an impact portion that contacts the cushioning material to apply an impact, and the impact portion has a curved surface with a radius of curvature R of 60 mm or more and 180 mm or less. In the impact absorbing floor material according to any one of claims 1 to 3,
The shock-absorbing floor material is characterized in that the cushioning material has a thickness of 7 mm or more and 80 mm or less. The impact absorbing floor material according to any one of claims 1 to 4,
The shock-absorbing floor material is characterized in that the cushioning material is made of ultra-soft urethane resin for molding.

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