UNIT CELL OF A NETWORKED STRUCTURE

Abstract

UNIT CELL OF A NETWORK STRUCTURE One aspect of the invention relates to a unit cell (1) of a network structure (5), characterized in that it comprises three levels: a first level I of star-shaped polygonal form with branches (2, 20, 21) of different heights, alternating or not; a second level II connected to the first level I and forming a surface of revolution (3) terminated by an S-shaped rim (30); and a third level III connected to the second level II and comprising flexible lamellae (4) distributed uniformly around the periphery of the S-shaped rim (30). Figure to be published with the abbreviation: Figure 6

Description

Title of the invention: UNIT CELL OF A NETWORKED STRUCTURE TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of a network structure and more particularly the unit cells composing it as well as its use.

[0002] The present invention relates to a unit cell, the network structure and a body protection. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] A multitude of network structures exist for various applications, including protecting certain parts of the body. However, although deformable, these structures are often not flexible enough to allow sufficient freedom of movement to make one "forget" that one is wearing protection.

[0004] Indeed, it is necessary to protect the backs of users during a violent fall on hard surfaces while allowing freedom of rotational movement. For sliding sports such as skiing, snowboarding, rollerblading, skateboarding, and downhill biking, protective gear exists to ensure safety during acrobatic maneuvers and to allow users to push their limits without fear for their safety.

[0005] Existing solutions are presented in the form of superimposed layers of foam of different hardnesses or of absorbent structure in the form of injected thermoplastic plate.

[0006] Thus, some protective devices are made of rigid plastic, others of molded foam or reinforced textile. However, these devices may not be flexible enough to follow the body's movements and therefore cannot offer optimal protection against injury.

[0007] Rigid back protectors are therefore not flexible enough to follow the movements of the body, which can lead to a lack of protection or even injuries.

[0008] Reinforced textile protectors also exist, but they are not designed to adapt to body movements. Textile protectors can also be difficult to clean and maintain.

[0009] Molded foam protectors may be more comfortable, but they are not strong enough to effectively protect against injuries.

[0010] There is document FR2976775 disclosing a back protection device comprising a deformable support and a network structure extending over a surface of said support to provide back protection against impacts. However, it does not provide the necessary freedom of movement to allow you to "forget" that you are wearing protection, it is also not breathable which makes it difficult to wear for long periods.

[0011] There is therefore a need for protection that is flexible, breathable and sufficiently rigid to protect a user. Summary of the invention

[0012] The invention offers a solution to the problems mentioned above, by allowing the realization of a network structure from a particular unit cell.

[0013] One aspect of the invention relates to a unit cell of a network structure, characterized in that it comprises three levels: • a first level I of star-shaped polygonal form with branches of different heights, alternating or not, • a second level II connected to the first level I and forming a surface of revolution ending in an S-shaped rim and, • a third level III connected to the second level II and comprising flexible strips evenly distributed around the periphery on an S-shaped rim.

[0014] Each level has specific characteristics. The first level is used for force transmission and shock absorption; it ensures a certain rigidity and prevents perforations. The second level offers high compression resistance, notably thanks to the S-shaped rim, which is important for distributing the impact force over a larger surface area, thus helping to reduce the severity of impact damage. The third level provides shock absorption and improved comfort.

[0015] The branches of the star will preferably be of identical shape.

[0016] Advantageously, the surface of revolution is a cone of revolution or a cylinder of revolution. The cone of revolution, like the cylinder of revolution, are shapes that have good compressive strength and, because they are hollow, they remain lightweight.

[0017] Advantageously, the cone of revolution has a flared portion oriented towards the first level. In this case, the second level is formed by the stacking of two coaxial cones along the axis of revolution of said cones, the second cone being constituted by a portion of the S-shaped rim. The apex of the lower cone is connected to the lower cone by a surface that follows the shape of a Fermat spiral (S-shape), creating a tangential transition.

[0018] Advantageously, the flexible slats are curved outwards. The outward curvature of the slats provides a larger shock-absorbing surface area.

[0019] Advantageously, the star polygonal shape comprises an even number of branches, preferably six. The minimum even number of branches is four. This allows for better cooperation between the branches (the most optimal) of the cells in a network structure.

[0020] Advantageously, the star polygonal shape comprises an odd number of branches. The minimum number of branches is then three.

[0021] Advantageously, the unit cell comprises the same number of flexible lamellae and star-shaped polygonal branches. This facilitates the construction of a network structure.

[0022] A second aspect of the invention relates to a network structure comprising unit cells with at least one of the preceding characteristics. The alternating vertical branches of the first level of the star-shaped polygonal unit cell allow an upper branch of one unit cell to interlock with a lower branch of an adjacent unit cell. The upper and lower branches can thus adjust to absorb impacts and reduce pressure on certain parts of the network structure.

[0023] Advantageously, the lamellae of two adjacent unit cells are linked together, forming a continuous link. The unit cells of the network structure are thus linked to one another, making it possible to create a continuous network structure.

[0024] Advantageously, the network structure is produced by additive manufacturing. Additive manufacturing can be used with a thermoplastic material such as polyurethane (TPU), and the process can be, for example, HP's Multi Jet Fusion (MJF). TPU is a flexible and durable material that is often used in the production of 3D products, such as flexible parts and coatings.

[0025] A third aspect of the invention is a body protection comprising the preceding network structure.

[0026] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0027] The figures are presented by way of example and in no way limit the invention.

[0028] [Fig. 1] is a cross-section of a unit cell according to the invention,

[0029] [Fig.2] is a top perspective view of a first level of two cells nested unitary units,

[0030] [Fig.3] is a section of a second level of a unit cell,

[0031] [Fig.4] is a top perspective view of a second level of a cell unitary,

[0032] [Fig.5] is a top perspective view of a third level of a cell unitary,

[0033] [Fig.6] is a top perspective view of several unit cells forming a network structure,

[0034] [Fig.7] is a profile view of a folded network structure on the side of the third level,

[0035] [Fig.8] is a profile view of a folded network structure on the side of the first level. DETAILED DESCRIPTION

[0036] Unless otherwise specified, the same element appearing on different figures has a unique reference.

[0037] In the rest of the description, "top" or "upper" will refer to the top of figures 1 to 6, and "bottom" or "lower" to the bottom of said figures.

[0038] The unit cell 1 illustrated in [Fig. 1] is composed of three interconnected levels: • a first level I of star-shaped polygon with branches 2 of different heights, alternating or not, • a second level II comprising a surface of revolution 3 ending in an S-shaped rim 30, and • a third level III comprising flexible slats 4.

[0039] The first level I, located at the top and shaped like a star, comprises upper arms 20 and lower arms 21. The center of the star, passing through an axis X, has a central space 22. This difference in height allows an upper arm 20 of one unit cell to be fitted with a lower arm 21 of another unit cell. The central space 22 allows air to circulate, reducing raw material consumption and facilitating sanding during manufacturing. Preferably, the upper arms 20 and lower arms 21 are identical in shape. The arms are uniformly spaced, meaning that, viewed from above, all adjacent arms form the same angle. The lower arms 21 include a projection 210 at the bottom for connection with the second level II. The length of each side and the number of sides of each arm 2 are determined by the precise geometric specifications related to the intended use.

[0040] The second level II comprises a surface of revolution 3 with axis X, a cone of revolution 31 in the illustrated example. This surface of revolution 3 is hollow, defining an intermediate cavity 33, and terminates at its upper part by a base ring 32 which is connected to the first level I. This base ring 32 is thicker than the rest of the surface of revolution 3, which allows for a better connection with the protrusions 210 of the first level I. The surface of revolution 3 terminates at its lower part by a rim 30 in the shape of S, the lower end 300 of the S is preferably directed outwards from the surface of revolution 3. The S shape of the rim 30 acts as a shock absorber in case of impacts, allowing the second level II to collapse and absorb the energy.

[0041] The third level III, located in the lower part, comprises several flexible lamellae 4, preferably of identical shape, connected at the top to the rim 30 at the lower end 300 of the S. The number of lamellae 4 may be identical to the number of branches 20 and 21 of the star shape. These lamellae 4 are preferably curved radially outwards.

[0042] The unit cell 1 enables the realization of a visible network structure 5 [Fig. 6]. This structure 5 connects several identical unit cells 1 on two levels in the following way: • for the first level I: the upper branches 20n of a first unit cell In overlap with a lower branch 21n+l of a neighboring unit cell ln+1 (or ln-1), • for the third level III: the 4n lamellae of a first unit cell In is connected with a 4n+l lamella of a neighboring unit cell ln+1.

[0043] Thus in the illustrated example, the unit cell 1 has six branches 2 comprising three upper branches 20 and three lower branches 21, and six lamellae 4. The six lamellae 4 are preferably placed below the six branches 2.

[0044] It can be seen [Fig. 6] that each of the upper branches 20n can be superimposed with a lower branch 21n+l of a neighboring unit cell ln+1, and each lamella 4n can be connected with a lamella 4n+l of a neighboring unit cell ln+1. The resulting network structure is continuous by means of the lamellae 4 and nested by the branches 2.

[0045] The alternating upper and lower sections allow for optimal distribution of the load applied to the network structure 5, thereby improving its mechanical resistance, like scales. The upper branches 20 and lower branches 21 can adjust to absorb impacts and reduce pressure on certain parts of the structure. Furthermore, the geometric shape of the regular star polygon offers greater stability, which is particularly suitable for applications requiring impact protection because, in this case, the upper branches 20 can rest on the adjacent lower branches 21 and thus reinforce the structure.In the event of an impact, the upper section, consisting of all the upper branches 20, transmits the impact energy from the affected upper branch to other nearby upper branches via the lower branches 21, which can then absorb the energy and limit the bending caused by collisions in the neighboring branches. The upper section also provides additional protection in the event of perforation by an object. The deformation of the network structure 5 when a force or impact is applied to it can be seen [Fig. 8]. In the upper part of the network structure 5, this deformation leads to a hardening of the network structure. The branches overlap compactly without leaving any gaps, thus providing effective protection.

[0046] The S-shaped rim 30 connects the second level II and the third level III. This rim 30 acts as a shock absorber, allowing the second level II to compress and absorb the energy. The second level II offers high compressive strength, which is important for distributing the impact force over a larger area, thus helping to reduce the severity of impact damage.

[0047] Furthermore, the cone shape of the illustrated example maximizes rigidity while minimizing weight, which is important for applications such as body or back protection where additional weight can cause discomfort for the user. The use of a cone shape also allows for a smooth transition between the different parts of the structure, which helps reduce localized stress points and ensures a uniform distribution of impact force across the entire network structure. Finally, the cone is a design that is easy to produce using 3D printing techniques, which can help reduce production costs and lead times.

[0048] The connection of the adjacent slats 4 allows for perfect cooperation between the different unit cells 1 without requiring further assembly. These junctions between the unit cells 1 allow for an extension of the network structure 5 during user movements due to the flexibility of the slats 4. The third level III can transmit the impact force to other parts of the network structure 5, thus improving comfort and providing better protection for the user. The arrangement of the slats around the intermediate section also allows for better adaptation to the user's movements for increased comfort. As can be seen [Fig. 7], the deformation of the network structure 5 on the side of the third level III, in contact with the user, is very flexible, giving the network structure suppleness when a force is applied on that side.

[0049] The network structure 5 is preferably produced by additive manufacturing using a thermoplastic material such as polyurethane (TPU), thermoplastic polyamide (TPA), polyethylene (PE), polypropylene (PP), polyvinyl (PVC), or polystyrene (PS). TPU is a flexible and durable material often used in the production of 3D printed products, such as flexible parts and coatings. The network structure is preferably made of a single material, which simplifies production processes, enabling the rapid and efficient production of customized protective devices for users, and these thermoplastics can be recycled.

[0050] The choice of materials can also determine mechanical properties such as TPU offers excellent compressive strength, flexibility, impact resistance, and durability. It is a flexible and durable material that is also water and impact resistant, making it particularly suitable for use in protective equipment.

[0051] An HP™ Multi Jet Fusion (MJF) printer, a 3D printer, or other additive manufacturing equipment may be used to produce the network structure 5. This process uses a print head that sprays molten plastic powder onto a powder bed to build the object. The print head is guided by digital files that define the shapes, dimensions, and properties of the finished product. The molten powder is solidified to form a solid, uniform layer, and then a new layer of powder is sprayed onto the bed to build the next layer of the object.

[0052] The process can be adjusted to fine-tune the mechanical and flexibility properties of the body protection. With MJF technology, it is possible to produce a one-piece network structure without having to assemble the individual parts. This minimizes assembly errors and improves the quality of the final product. Furthermore, one-piece production optimizes material consumption and minimizes waste. Using MJF technology, it is possible to produce high-quality objects with optimal mechanical properties for use in industrial or sporting applications.

[0053] The network structure 5 can be used for sports protective equipment such as body protection such as back protectors, shin guards, knee protectors, shoulder pads, elbow pads, etc. In this case, the first level I is placed on the outside and the third level III as close as possible to the user.

[0054] Depending on the maximum impact that the network structure must absorb, its thickness is calculated by simulation and defines the dimensions of a cell. The length and thickness of each junction are dimensioned to minimize resistance to elongation and allow for movement. Thanks to its numerous voids, the network structure offers high breathability and reduced weight.

Claims

Claims

1. Unit cell (l) of a network structure (5), characterized in that it comprises three levels: - a first level I of polygonal star shape with branches (2, 20, 21) of different heights, alternating or not - a second level II connected to the first level I and forming a surface of revolution (3) terminated by an S-shaped rim (30) and, - a third level III connected to the second level II and comprising flexible strips (4) distributed uniformly on the periphery of the S-shaped rim (30).

2. Unit cell (1) according to claim 1, characterized in that the surface of revolution (3) is a cone of revolution or a cylinder of revolution.

3. Unit cell (l) according to the preceding claim, characterized in that the cone of revolution has a flared part oriented towards the first level I.

4. Unit cell (1) according to one of the preceding claims, characterized in that the flexible slats (4) are curved outwards.

5. Unit cell (1) according to one of the preceding claims, characterized in that the star-shaped polygonal shape comprises an even number of branches (2, 20, 21), preferably six.

6. Unit cell (1) according to one of claims 1 to 4, characterized in that the star-shaped polygonal shape comprises an odd number of branches (2, 20, 21).

7. Unit cell (1) according to one of the preceding claims, characterized in that it comprises the same number of flexible slats (4) and branches (2) of the star-shaped polygonal shape.

8. Network structure (5) comprising unit cells (1) according to one of the preceding claims.

9. Network structure (5) according to the preceding claim characterized in that the slats (4) of two adjacent unit cells (1) are connected to each other forming a continuous link.

10. Network structure (5) according to claim 8 or 9, characterized in that it is produced by additive manufacturing.

11. Body protection comprising a network structure (5) according to one of claims 8 to 10.