FR3067615A1 - BOARD OF SLIDERS - Google Patents

Abstract

Snow sliding board (1), having a structure including: • a lower set formed (2) of a bordered gliding sole (7) of edges (8) and one or more layers (9) of lower reinforcement ; An upper assembly (3) formed of one or more upper reinforcing layers (12) and an upper protective and decorative layer (11); A core (4) interposed between the lower and upper sets (9) (3); An elongated element (20) extending in the longitudinal direction of the board, separating the core into two parts (21, 22), and coming into contact with the upper (3) and lower (2) assemblies, characterized in that the elongated element (20) is formed by the assembly of at least three layers extending vertically between the upper (3) and lower (2) assemblies, the three layers comprising a central layer (30) made of a material having a transverse Young's modulus greater than the transverse Young's modulus of the core material (21, 22), and two side layers (31, 32) in contact with the core layer (30), and made of an elastomeric material.

Description

SLIDING BOARD

Technical area

The invention relates to the field of sliding sports using a board, and in particular snow sliding sports. It relates more specifically to an internal structure of a board, and in particular of skiing or snowboarding. It relates more particularly to a structure of the internal core of such a board, intended to improve both the performance and the comfort of the user.

Previous techniques

In general, a snow gliding board has a structure comprising a lower assembly and an upper assembly, each including reinforcing layers, which are separated by an internal core making it possible to separate these rigid reinforcement layers from the fiber. neutral. Such a sandwich type structure thus has a rigidity in flexion and in torsion which allows the board to evolve on the snow while ensuring both the contact of the gliding sole on the snow, and grip of the side edges when the board is tilted.

In practice, the reinforcing layers are made of materials having a high rigidity, based on metal, or on fibrous material impregnated with resin in the form of composite material. The core is for its part made of a material which must have multiple qualities which are mainly a mass as small as possible, and a certain resistance to crushing.

Among the materials giving satisfaction for this core, we can note light woods, such as poplar or balsa, or even corrugated cardboard, with regard to the boards whose core is made before the molding of the whole structure. For skis whose core is manufactured during molding, by injecting an expandable material into the space formed between the upper assembly and the lower assembly, the polyurethane foam is

-2 Frequently used. It has already been proposed to produce complex cores, combining different types of materials.

Thus, document EP 2 384 464 describes a gliding board which is in the form of a snowboard, the core of which has an element of greater rigidity in the central part. This element is intended to serve as a side edge when the board is cut in two along a longitudinal plane, in order to ensure the seal vis-à-vis the rest of the core.

We have also described in document FR 2 655 864, a gliding board combining different zones arranged parallel in the longitudinal direction. These different zones are arranged in such a way that they can move relative to one another during the molding of the board, so as to absorb deformations induced by the presence of localized reinforcing elements, or so as to produce cores which have broken shapes.

Statement of the invention

One of the objectives of the invention is to provide a gliding board which has both good grip properties, in particular by improving these properties in transverse bending, with a behavior which is nevertheless comfortable.

To do this, the Applicant has designed a snow gliding board, which has a structure including:

• a lower assembly formed by a gliding sole bordered by edges, and one or more layers of lower reinforcement;

• an upper assembly formed by one or more layers of upper reinforcement, and an upper layer of protection and decoration;

• a core interposed between the lower and upper assemblies;

-3 • a long element extending in the longitudinal direction of the board, separating the core into two parts, and coming into contact with the upper and lower assemblies.

According to the invention, this gliding board is characterized in that the elongate element is formed by the assembly of at least three layers extending vertically at least over the entire height of the core. These three layers comprise a central layer made of a material having a transverse Young's modulus greater than the transverse Young's modulus of the material making up the core, and two lateral layers coming into contact with the central layer, and made of an elastomeric material.

The invention consists in segmenting the core so as to increase its bending stiffness, its transverse bending stiffness, its torsional stiffness compared to a monolithic core without elongate element, while increasing the crushing resistance of the core. These differences in stiffness are however felt to a lesser extent on the board since the lower and upper reinforcements strongly stiffen the core.

In particular, the improvement of the mechanical properties, in particular in transverse bending, thanks to the specific structure of the core makes it possible to favor the use of fibrous reinforcements which have limited transverse mechanical properties, but which are easier to conform than the metallic reinforcements.

Furthermore, the fact of separating the two parts of the core by this elongated element appreciably modifies the dynamic behavior of the board. Indeed, the assembly obtained by the two parts of the core and the elongate element behaves like an assembly formed by a main mass with which is associated a dynamic beater. Thus, when the board tips over the edge, the part of the core located close to the edge in contact with the snow constitutes the main mass and the assembly formed by the other part of the core constitutes the mass of the beater while the element slender constitutes stiffness and / or damping

-4beater. This makes it possible to obtain a shift in the resonance frequencies of the board, or even also a reduction in the level of amplitude at the resonance frequencies, this making it possible to obtain a board vibrating less on the edge, more anchored in its trajectory, the user appreciating thus the comfort obtained due to the reduction in vibrations. The elongated element being formed of three layers of elastomer-reinforcement-elastomer type, this makes it possible to choose the stiffness of the beater, more precisely by the choice of the central reinforcement layer and the damping of the beater by the choice of the elastomeric side layers . In addition, the presence of the central reinforcement makes it possible to avoid significant transverse deformation and a break between the two parts of the core, and makes it possible to create inside the elastomeric layers of the shear to dissipate energy and dampen the level of vibrations. .

The invention can be implemented on different types of cores, and in particular cores made of wood, or of injected foam, typically based on polyurethane.

In practice, the elongate element extends over part of the length of the board, or even over the entire length of the core. In the first case, it can be located at different levels of the board, either at the front or at the rear, preferably with a presence at the level where the forces on the edges are exerted during the turning phases, know at the level of the area where the binding is installed.

In the first case, the characteristic elongated element is associated with the other parts of the core before molding, or even during molding. In the case of an injected ski, the characteristic element can be placed inside the mold, and delimits two volumes into which the foam of the core will be injected during the molding operation.

In practice, the elongate element may have a central layer made of a material chosen from the group comprising aluminum, acrylonitrile butadiene styrene (ABS), or even composite materials based on long or short fibers.

In practice, there are good results in terms of grip of the board when cornering when the material of the central layer has a transverse Young's modulus greater than three times the Young's modulus of the core material, preferably greater than ten. time.

In practice, the central layer of the elongate element may have a width of between 0.3 and 4 mm, preferably between 0.6 and 2 mm

It is possible to adjust the desired mechanical properties by varying both the width of the central layer of the elongate element, and the material used. Thus, good results have been obtained when the combination of these parameters means that the product between the width of the central layer and the Young's modulus of the material constituting it is greater than 10,000 mm.MPa, and preferably 30,000 mm .mpa.

In practice, the side layers of the elongate element can be made of a material chosen from the group comprising rubber, thermoplastic polyurethanes, styrene-ethylene-butadiene-styrenes (SEBS), or even other materials with properties. elastomeric.

In practice, the material of the lateral layers can advantageously be a viscoelastic material, which has a sufficient damping coefficient, and optimized for operation over a temperature range from -20 ° C. to + 5 ° C., which allows d '' ensure efficient dissipation of mechanical energy generated in the structure when the board is deformed.

In practice, these lateral layers can advantageously have a width of between 0.1 and 1 mm, preferably between 0.3 and 0.7 mm.

In particular, in the case where the board is intended for alpine skiing, for example, a first type of comfortable ski is obtained by using a slender element composed of a central layer of ABS of 2mm thickness covered on each of its two lateral sides with a 0.5mm thick rubber layer. A second type of comfortable and more efficient ski can be obtained by using a slender element composed of a layer of central aluminum 0.6mm thick covered on each of its two lateral sides with a layer of rubber 0.5mm thick. thickness.

The principle of the invention can be declined by including several similar elongated elements arranged in parallel, either spaced from one another so as to form a greater number of portions of the core to create several dynamic beaters, or joined to each other to modify the parameters of the dynamic mixer and in particular its parameters of mass, stiffness and / or damping.

Brief description of the figures

The manner of carrying out the invention, as well as the advantages which flow therefrom, will emerge clearly from the description of the embodiment which follows, with the support of the appended figures in which:

FIG. 1 is a cross-sectional view of a gliding board according to the invention,

FIG. 2 is a detailed view of zone II of FIG. 1.

- Figure 3 is a top view of the core of the board of Figure 1.

Of course, the dimensions and proportions of certain components of the invention could have been distorted, exaggerated and deviated from reality, in order to make the invention understood.

-7Manner of carrying out the invention

As illustrated in FIG. 1, the gliding board 1 comprises a lower assembly 2, and an upper assembly 3, separated by a core 4. More specifically, the lower assembly 2 comprises a gliding sole 7, typically based of polyethylene, on which the fins of the metal edges rest laterally. In the illustrated form, this lower assembly 2 also includes a reinforcing layer 9. This layer can be produced from different materials and in particular based on metal, or preferably for questions of overall weight, by composite materials, including high tenacity fibers, such as glass, aramid, basalt or the like, mainly oriented parallel to the longitudinal length of the board. It is of course possible that the lower assembly 2 includes several reinforcing layers, of similar or different nature and size, without departing from the scope of the invention.

The board 1 also includes an upper assembly, which comprises from the top a layer 11 of decoration and protection, resting on a reinforcing layer 12. The layer 11 of decoration and protection can be produced in different ways, and include on its lower face of the printed areas visible from the upper face of the board, or even of the transparent areas, making it possible to make the reinforcing layer 12 visible from the outside. Multiple variants can be envisaged with regard to this layer decoration and protection, without departing from the scope of the invention.

In the illustrated form, the upper assembly 3 comprises a reinforcing layer 12, which can also be produced in different ways, and in particular in metal or preferably in composite material. This reinforcing layer 12 can adopt different geometries as a function of the overall geometry of the board, and in particular of the possibly three-dimensional shape of the upper face of the board. This layer can also be multiple, by combining different thicknesses of identical, similar or different nature.

-8The upper 3 and lower 2 assemblies are separated mainly by the core 4, which is bordered laterally by the edges 5 which protect the core from external humidity, and which ensure the transmission of forces from the upper assembly to the edges 8.

According to one aspect of the invention, this core 4 has a particular structure, since it includes a long element 20, which separates the core 4 into two left side parts 21, and right side 22. This long element extends as illustrated in Figure 3 over the entire length of the core, along its median longitudinal plane. However, in other variants not shown, this elongated element may be shorter, and only extend over part of the length of the core.

As illustrated in FIG. 2, this elongate element 20 extends vertically between the upper 3 and lower 2 assemblies and has a height identical to that of the core. In other variants, the elongate element may be higher than the core and be inserted between two parts of an upper (or lower) reinforcement, penetrating into the upper (or lower as the case may be) assembly. In a variant not illustrated, the upper or lower assembly may each include a localized layer, intended to interface between the elongate element and the rest of the upper or lower assembly.

This elongate element 20 consists of several layers assembled vertically, and interposed between the two parts 21, 22 of the core. The central layer 30 of the elongate element is made of a material much more rigid than the rest of the core, and more precisely which has a Young's modulus in the transverse direction significantly higher than that of the material constituting the rest of the core.

-9Different materials can be used to make this central layer 30, and in particular metallic materials and in particular based on aluminum such as the aluminum alloy 7075, also known under the name "Zicral". Good results have been obtained with a thickness ei of this central layer 30 close to 0.6 mm. The transverse Young's modulus of this material is close to 70,000 MPa, to be compared with the transverse Young's modulus of the woods used for manufacturing cores, is generally between 500 and 1,000 MPa. It will be noted in particular that, given the essentially longitudinal orientation of the fibers of the wood used for manufacturing the cores, the Young's modulus in the longitudinal direction of these materials is generally higher, between 5000 and 15000 MPa.

In an alternative embodiment, it is possible to use to form the central layer 30 of the elongate element 20 a polymeric material, and in particular ABS, with a thickness ei of the order of 2 mm, this material having a modulus de Young of around 1,800 MPa.

According to the invention, this central layer 30 is bordered by two lateral layers 31, 32 which are made of an elastomeric material. Good results have been obtained using rubber, with a thickness e ₂ of the order of 0.5 mm.

The different layers of the elongated element are assembled together and with the rest of the core by gluing for example.

Thanks to the presence of the characteristic elongated element, an increase in the bending stiffness of the core has been observed. It being understood that the bulk of the bending stiffness of the board is imparted by the presence of the reinforcing layers of the upper and lower assemblies, the impact of this increase in bending stiffness of the core on that of the board is, however, marginal. At the same time, there is an increase in the stiffness in transverse bending and in torsion of the core. In

Effect, in particular in the case where the reinforcing layers of the upper and lower assemblies are based on unidirectional fibrous materials, oriented longitudinally, the stiffness in transverse bending imparted by these reinforcements is relatively limited compared to that measured in the longitudinal direction . The rigidity of the characteristic slender element is particularly important for the dynamic behavior of the board. An increase in torsional stiffness has also been observed due to the presence of the characteristic slender element.

In addition, the use of an elastomeric, and advantageously viscoelastic, material makes it possible to generate vertical shear phenomena during the flexural deformation of the board, with energy dissipation making it possible to generate a certain damping.

Overall, the behavior of a board according to the invention, and in particular its dynamic behavior on snow, makes it possible to obtain a board with improved grip, when the board is on the edge and a sharper inscription in the curves. due to the attenuation of vibrations, the board remaining more easily inscribed on its path. At the same time the damping effect generated by the association of a rigid material and an elastomeric material within the elongated element brings to the board a certain softness in the deformation, and therefore a board more comfortable for the user.

Of course, even if the invention has been described in the examples for a “sandwich” type structure, it can also be applied for so-called “shell” overall structures, in which the upper assembly extends laterally vertically up to '' to join the assembly below the plumb of the edges, encompassing the core without requiring side edges.

Claims (9)

1 / Snow gliding board (1), having a structure including: • a lower assembly formed (2) of a gliding sole bordered (7) with edges (8) and one or more layers (9) of lower reinforcement; • an upper assembly (3) formed by one or more upper reinforcement layers (12) and an upper protection and decoration layer (ii); • a core (4) interposed between the lower and upper assemblies (9) (3); • a long element (20) extending in the longitudinal direction of the board, separating the core into two parts (21, 22), and coming into contact with the upper (3) and lower (2) assemblies, characterized in that the elongate element (20) is formed by the assembly of at least three layers extending vertically between the upper (3) and lower (2) assemblies, the three layers comprising a central layer (30) made of a material having a transverse Young's modulus greater than the transverse Young's modulus of the material making up the core (21, 22), and two lateral layers (31, 32) coming into contact with the central layer (30), and made of an elastomeric material. 2 / Gliding board according to claim 1, characterized in that the core (21, 22) is made of wood. 3 / Gliding board according to claim 1, characterized in that the core (21, 22) is made of injected foam, typically based on polyurethane. 4 / Gliding board according to claim 1, characterized in that the central layer (30) is made of a material chosen from the group comprising aluminum, acrylonitrile butadiene styrene, composite materials based on fibers. -125 / Gliding board according to claim 1, characterized in that the material of the central layer (30) has a transverse Young's modulus greater than ten times the Young's modulus of the core material. 6 / Gliding board according to claim 1, characterized in that the central layer (30) has a width of between 0.3 and 4 mm. 7 / Gliding board according to claim 1, characterized in that the product 10 between the width of the central layer and the Young's modulus of the material which constitutes it is greater than 10 000 mm.Mpa. 8 / Gliding board according to claim 1, characterized in that the lateral layers (31, 32) are made of a material chosen from the group Including rubber, thermoplastic polyurethanes, styrene-ethylene-butadiene-styrene. 9 / Gliding board according to claim 1, characterized in that the lateral layers have a width of between 0.1 and 1 mm, 20 preferably between 0.3 and 0.7 mm. 10 / Gliding board according to claim 1, characterized in that it comprises several similar elongated elements arranged parallel in the transverse direction.