Playground cushioning system comprising a stack of one layer of elastomeric granules and one layer of wood chips

Abstract

This playground cushioning device (1) comprises a layered structure including: - A layer of elastomeric granules (5) resting on a surface (3); and - A layer of wood chips (7) resting by gravity on the layer of elastomeric granules (5). Figure for the abbreviation: Fig. 1

Description

Title of the invention: Playground cushioning device comprising a stack of a layer of elastomeric granules and a layer of wood chips. Technical field

[0001] The present invention relates to the field of public playgrounds, particularly for children.

[0002] In particular, the present invention relates to the field of cushioning floors and devices used in children's play areas, for example positioned near attractions in order to reduce the risk of injury during falls.

[0003] In general, the invention applies to any damping device. Previous techniques

[0004] In the field of children's play areas installed in public spaces, the French and European standard NF EN 1176 requires a certain level of cushioning.

[0005] To meet this requirement, there are several techniques and materials that can be used.

[0006] The most common solution is the use of a layer of elastomeric granules mixed with glue, the granules being more commonly called EPDM (ethylene-propylene-diene monomer).

[0007] For example, between 10% and 20% of the weight of the EPDM granules must be added as glue in order to make the shock-absorbing floor strong enough not to degrade over time.

[0008] Furthermore, the thickness of the layer varies according to the fall heights defined by the approval of the installed structures, this thickness being able to range from 10 to 120 mm to meet the standard NF EN 1176.

[0009] Thus, for an average play area of ​​100 m2, with a thickness of 5 cm, 4000 kg of EPDM granules and 500 kg of glue are required.

[0010] This solution is the most used because, despite its significant manufacturing and installation cost, maintenance costs are lower.

[0011] However, this alternative is very glue-intensive, particularly using PU (polyurethane) glue, and causes pollution during its manufacture and recycling, if applicable. Indeed, the use of glue and EPDM granules generates microplastics.

[0012] Moreover, there are inherent dangers in the application of the glue, the latter generating exposure of the respiratory tract of an operator during installation, not to mention allergies related to the use of glues, cleaners and smoothers.

[0013] A second solution is a shock-absorbing floor made of wood chips simply piled up to a certain thickness.

[0014] This solution has several advantages due to the absence of glue or granules in EPDM, thus generating no microplastics and requiring no chemical products for installation.

[0015] However, this method has a disadvantage since the wood chips are prone to rotting: as soon as rainwater seeps into the wood chip damping soil, the wood chips in contact with the soil potentially come into contact with stagnant water. Mycelium develops, these wood chips rot and contaminate the other wood chips, so that the entire damping soil is subject to rot and must be completely renewed regularly, which represents a significant cost in terms of materials and labor.

[0016] Furthermore, since the wood chips are not glued, users of the playground often scatter them through repeated foot traffic on the impact-absorbing surface. It is therefore necessary for an operator to replace them daily on the impact-absorbing surface, or even to add more regularly to ensure that the thickness of the impact-absorbing surface remains sufficient at all times. Description of the invention

[0017] The present invention therefore aims to overcome the aforementioned disadvantages and to provide a playground damping device that is as environmentally friendly as possible, while also being as durable as possible with regard to its maintenance.

[0018] The present invention relates to a damping device for a playground comprising a layer stack characterized in that it comprises:

[0019] - A layer of elastomeric aggregates resting on a soil. The soil is, for example in the ground and the layer of elastomeric aggregates prevents the formation and development of mycelium and generally prevents the rotting of the entire subsequent layer of wood chips; and.

[0020] - A layer of wood chips resting by gravity on the layer of aggregates in elastomer.

[0021] Thus, the invention offers the same advantages as a shock-absorbing wood chip floor while exhibiting high resistance to rot, since only the elastomeric granule layer is in contact with the ground, and therefore with standing water. Because the elastomer is rot-resistant, the wood chips will not deteriorate and will have a much longer lifespan.

[0022] In a particular embodiment, the sum of the thicknesses of the elastomer aggregate layer and the wood chip layer is between 16 and 50 centimeters, preferably between 20 and 40 centimeters.

[0023] For example, the layer of elastomeric granules measures between 10 and 15 cm thick and the layer of wood chips measures between 20 and 25 cm thick depending on the fall height of the playground structure intended to accommodate the cushioning device.

[0024] Advantageously, the damping device further comprises a top layer comprising a mixture of elastomeric granules and glue, preferably polyurethane glue, and resting on the layer of wood chips.

[0025] Other types of top layer can also be applied, including by other methods.

[0026] In a particular embodiment, the upper layer comprising a mixture of elastomeric granules and glue also comprises wood chips, preferably at least 30% wood chips.

[0027] Advantageously, the wood chips have an average size of between 1 and 100 millimeters, preferably between 5 and 80 millimeters, and wherein the elastomer granules have an average size of between 1 and 50 millimeters, preferably between 1 and 10 millimeters.

[0028] Advantageously, the thickness of the elastomeric aggregate layer is between 1 and 15 centimeters, preferably between 5 and 10 centimeters.

[0029] Preferably, the damping device further comprises a layer of textile, preferably geotextile, permeable to water and positioned between the layer of wood chips and the layer of elastomeric granules. This textile layer prevents the layer of wood chips and the layer of elastomeric granules from mixing.

[0030] Advantageously, the damping device comprises a layer of textile, preferably geotextile, permeable to water and positioned between the layer of elastomeric aggregates and the soil.

[0031] In one embodiment, the damping device comprises a board, preferably made of plastic, positioned horizontally and such that one of the dimensions of said board extends vertically, the two layers of textile being fixed at different heights of said board according to its vertical dimension.

[0032] The present invention also relates to a method for manufacturing a damping device as defined above, which comprises the following steps:

[0033] - Laying a first layer of textile on a floor;

[0034] - Fixing a board to the first layer of textile;

[0035] - Laying a layer of elastomeric granules on the first layer of textile;

[0036] - Laying a second layer of textile on the layer of elastomer granules;

[0037] - Fixing the second layer of textile to the board; and

[0038] - Laying a layer of wood chips on the second layer of textile. Brief description of the drawings

[0039] Other objects, features and advantages of the invention will become apparent from the following description, given solely by way of non-limiting example, and made with reference to the accompanying drawings in which:

[0040] [Fig.1] is a schematic cross-sectional view of the layers of the damping device according to the invention; and

[0041] [Fig.2] is a schematic representation of the steps in the manufacturing process of the damping device according to the invention. Detailed description of at least one embodiment

[0042] A schematic cross-sectional view of a damping device 1 for a public playground, for example a children's playground, is shown in [Fig.1].

[0043] The damping device 1 shown comprises a stack of layers arranged on a surface 3, such as soil in a park. The damping device 1 may be arranged on an undisturbed surface 3 or in a hole made in said surface 3.

[0044] Essentially, the damping device 1 comprises a layer of elastomeric granules 5 resting on a floor 3, as well as a layer of wood chips 7 resting by gravity on the layer of elastomeric granules 5.

[0045] The elastomeric granules 5 thus allow the wood chips 7 to be isolated from the ground 3 where water may stagnate. Spaces formed between the elastomeric granules 5 allow rainwater and air to enter, enabling the damping device 1 to dry quickly. The wood chips 7 are thus prevented from rotting.

[0046] Furthermore, the present damping device 1 contains few elastomeric granules 5 for damping equivalent to a state-of-the-art shock-absorbing surface. The damping device 1 therefore offers ecological advantages compared to the state of the art, and playground managers will thus be more inclined to use wood chips as a damping material.

[0047] Furthermore, neither the elastomeric granule layer 5 nor the wood chip layer 7 contains any glue. No glue, in particular no polyurethane glue is not used in one of these layers, which presents a strong ecological and health benefit.

[0048] The term elastomer means a rubber, preferably a synthetic rubber. In particular, the synthetic rubber may be of the ethylene-propylene-diene monomer (EPDM) type, preferably recycled.

[0049] In a particular embodiment, the elastomer granules 5 are of average size, otherwise called granularity, between 1 and 50 millimeters, preferably between 1 and 10 millimeters.

[0050] The thickness of the elastomer aggregate layer 5 is between 1 and 15 centimeters, for example between 5 and 10 centimeters.

[0051] The layer of wood chips 7 completes the damping device 1 so as to obtain a total thickness, in other words the sum of the thicknesses of the layer of elastomer granules 5 and the layer of wood chips 7, of between 16 and 50 centimeters, preferably between 20 and 40 centimeters.

[0052] Wood chips 7 are defined as chips, preferably untreated, of medium size, i.e., a particle size, between 1 and 100 millimeters, preferably between 5 and 80 millimeters. The wood used to make these wood chips 7 is, for example, bark or wood of pine, cedar, or any other tree. The wood comes, for example, from the recycling of shredded pallets.

[0053] Preferably, the wood chips undergo prior heat treatment by passing them through an oven at a predetermined temperature for a specified time. This heat treatment is applied to bring out the tannins so that the wood chips are more resistant to rotting.

[0054] In a particular embodiment, the layer of wood chips 7 is 20 to 30 cm thick while the layer of elastomer granules 5 is 10 to 15 cm thick so as to obtain a damping device 1 with a total thickness of between 20 and 45 cm, preferably between 30 and 40 cm.

[0055] Advantageously, the damping device 1 comprises a first layer of textile 9, preferably geotextile, permeable to water and positioned between the layer of elastomeric aggregates 5 and the soil 3.

[0056] This first layer of textile 9 allows water to infiltrate as much as possible into the soil 3 while preventing the elastomer granules 5 from mixing with said soil 3, for example from mixing with earth.

[0057] Preferably, the damping device 1 further comprises a second layer of textile 11, preferably geotextile, permeable to water and positioned between the layer of wood chips 7 and the layer of elastomer granules 5.

[0058] This second layer of permeable textile 11 allows water to seep into the ground 3, the ground 3 thus not being impermeable, while preventing the elastomer granules 5 and the wood chips 7 from mixing.

[0059] Geotextile is understood to be a permeable fabric, for example made of polymer.

[0060] The thickness of each of the textile layers 9 and 11 is small, for example between 0.1 millimeter and 1 centimeter.

[0061] Optionally, the damping device 1 includes a board 13, for example made of plastic, positioned horizontally and such that one of the dimensions of said board 13 extends vertically, the first and second layers of textile 9 and 11 being fixed at different heights of said board 13 according to its vertical dimension.

[0062] Thus, the distance separating the two textile layers 9 and 11 remains constant over time. The board 13, preferably extending over the entire thickness of the damping device 1, also forms a lateral barrier and prevents the elastomer granules 5 and wood chips 7 from escaping laterally, thus forming a tray for the damping device 1.

[0063] Advantageously, the damping device 1 further comprises a top layer 15 comprising a mixture of elastomeric granules and glue, preferably polyurethane glue, and resting on the layer of wood chips 7.

[0064] In a particular embodiment, and in order to reduce the quantity of elastomer granules used, the upper layer 15 comprising a mixture of elastomer granules, for example colored, and glue also includes wood chips, preferably at least 30% wood chips, even more preferably at least 50% wood chips.

[0065] This upper layer 15 contains glue and thus forms a rigid layer that prevents wood chips from the lower wood chip layer 7 from escaping. Therefore, it is no longer necessary for an operator to regularly add wood chips to the wood chip layer 7.

[0066] Alternatively, or in addition, the upper layer 15 includes a net preventing wood chips 7 from escaping.

[0067] Schematically represented in [Fig.2] are the steps of the manufacturing process of the damping device 1 as described above.

[0068] In order to implement said damping device 1, a step El is first carried out of laying the first layer of textile 9 on the floor 3.

[0069] Then, a step E2 is carried out of fixing a board 13 to the first layer of textile 9. Obviously, several boards 13 are positioned to delimit the perimeter of the damping device 1.

[0070] The boards 13 are for example positioned along metal rods (not shown) positioned vertically.

[0071] The next step E3 consists of placing the layer of elastomeric granules 5 on the first layer of textile 9.

[0072] Next, a step E4 is carried out of laying the second layer of textile 11 on the layer of elastomer granules 5.

[0073] The second layer of textile 11 is fixed to the board 13 so as to join all of these layers 9, 5, 11 in a step E5.

[0074] Then, step E6 is carried out, which involves placing the layer of wood chips 7 onto the second layer of textile IL

[0075] Finally, and optionally, a step E7 is carried out to lay the top layer 15 comprising a mixture of elastomeric granules and adhesive. This top layer 15 has, for example, a thickness of between 1 and 10 centimeters, preferably between 2 and 5 centimeters.

[0076] Regarding the damping performance of the damping device 1, a Head Injury Criterion (HIC) test was carried out with a 10-centimeter-thick layer of elastomeric granules 5 and a 20-centimeter-thick layer of wood chips 7. The total thickness of the damping device 1 is therefore 30 centimeters, which is the thickness recommended by French and European standards for a tray filled solely with wood chips for a playground structure with a fall height greater than 1.50 m, a 30 cm deep tray being recommended for a structure with a fall height of 0 to 1.50 m.

[0077] The HIC test was carried out according to method 2 of standard NF EN 1177+A1 and for drop heights between 1.50 and 3 meters. Compared with a wood chip tray according to the prior art, the damping device 1 according to the invention surprisingly exhibits damping capacities that are on average 55% higher.

[0078] Thus, the present invention offers performance superior to the prior art in every respect. For the same damping capacity, the thickness of the damping device 1 according to the invention could consequently be reduced compared to a conventional damping surface in order to reduce the amount of material used. The present invention also has the advantage of requiring less excavation and less labor, partly because the depth of the pits to be excavated for the damping system would be less due to the improved damping performance.

Claims

Demands

1. Damping device (1) for playground comprising a layer stack characterized in that it comprises: - A layer of elastomeric granules (5) resting on a ground (3); and - A layer of wood chips (7) resting by gravity on the layer of elastomeric granules (5).

2. Device according to claim 1, wherein the sum of the thicknesses of the elastomer aggregate layer (5) and the wood chip layer (7) is between 16 and 50 centimeters, preferably between 20 and 40 centimeters.

3. Device according to any one of claims 1 and 2, further comprising a top layer (15) comprising a mixture of elastomeric granules and glue, preferably polyurethane glue, and resting on the layer of wood chips (7).

4. Device according to claim 3, wherein the upper layer (15) comprising a mixture of elastomeric granules and glue also comprises wood chips, preferably at least 30% wood chips.

5. Device according to any one of claims 1 to 4, wherein the wood chips have an average size of between 1 and 100 millimeters, preferably between 5 and 80 millimeters, and wherein the elastomer granules have an average size of between 1 and 50 millimeters, preferably between 1 and 10 millimeters.

6. Device according to any one of claims 1 to 5, wherein the thickness of the elastomeric aggregate layer (5) is between 1 and 15 centimeters, preferably between 5 and 10 centimeters.

7. Device according to any one of claims 1 to 6, further comprising a layer of textile (11), preferably geotextile, permeable to water and positioned between the layer of wood chips (7) and the layer of elastomeric granules (5).

8. Device according to any one of claims 1 to 7, comprising a layer of textile (9), preferably geotextile, permeable to water and positioned between the layer of elastomeric aggregates (5) and the soil (3).

9. Device according to claims 7 and 8, comprising a board (13), preferably made of plastic, positioned horizontally and such that one of the dimensions of said board (13) extends vertically, the two layers of textile (9; 11) being fixed at different heights of said board (13) according to its vertical dimension.

10. A method for manufacturing a damping device 1 according to claim 9, comprising the following steps: - Laying (step E1) a first layer of textile (9) on a floor (3); - Fixing (step E2) a board (13) to the first layer of textile (9); - Laying (step E3) a layer of elastomeric granules (5) on the first layer of textile (9); - Laying (step E4) a second layer of textile (11) on the layer of elastomeric granules (5); - Fixing (step E5) the second layer of textile (11) to the board (13); and - Laying (step E6) a layer of wood chips (7) on the second layer of textile (11).

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