FR2818915A1 - Ski or snowboard has cut out portions in reinforcing layer corresponding to relief zones in upper protective surface - Google Patents

Abstract

The ski or snowboard has an upper surface with one or more relief zones and made up of an upper protective layer (10) with an upper reinforcing layer (11) beneath it, and a core (22) made from injected polymer foam. The upper protective layer is of a solid film material while the reinforcing layer has cut out portions corresponding to the edges of the relief zones so that the foam can pass through and fill the relief zones. The cut-away portions of the reinforcing layer can be covered by a mesh (30) that lets the foam through.

Description

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Domaine technique
L'invention se rattache au domaine des sports de glisse, et plus précisément à celui de la fabrication de planches de glisse telles que les skis alpins, les skis de fond ou les surfs des neiges. Elle concerne plus particulièrement les planches de glisse dont la face supérieure possède des zones en relief, c'est-à-dire des bossages ou des évidements présentant de relativement brusques ruptures de pente. Elle vise plus spécifiquement une structure et un procédé permettant d'obtenir de telles planches par injection du noyau in-situ, tout en conservant des qualités mécaniques conférées par la présence d'un renfort rigide. SLIDING BOARD

Technical area
The invention relates to the field of board sports, and more specifically to that of the production of board boards such as alpine skis, cross-country skis or snowboards. It relates more particularly to gliding boards, the upper face of which has raised areas, that is to say bosses or recesses having relatively abrupt breaks in slope. It relates more specifically to a structure and a process making it possible to obtain such boards by injection of the core in situ, while retaining the mechanical qualities conferred by the presence of a rigid reinforcement.

Previous techniques
Gliding boards, and in particular alpine skis, have elaborate shapes which are determined both for technical criteria and for aesthetic considerations.

 Thus, the document FR 2 696 354 has proposed a method for the manufacture of a ski, the upper face of which has recesses. This upper face has relatively marked slope breaks, forming steps of thickness. Such a ski is obtained from a pre-injected core whose upper face has the recesses. This embodiment is costly because it requires machining in the form of the core or, if this core is obtained by injection, the production of a complex mold, as well as pre-gluing of the various constituent elements.

 Another method of manufacturing gliding boards is known, which consists in placing a sole, an upper reinforcing layer and a protective layer in a mold, then injecting between the sole and the upper reinforcing layer, the components of a polyurethane foam capable of reacting in situ by expanding to form the core of the board. When the foam expands, the latter presses the upper reinforcing layer and the upper protective layer on the internal surface of the upper part of the mold.

 With such an in-situ injection process, if one wishes to obtain a board having reliefs on the upper surface, there are three main solutions.

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 In a first solution, a boss is produced firstly in the upper assembly by interposition of an element between the upper reinforcing layer and the protective layer; then, in a second step, the gliding board is carried out in the traditional way. Such a process is described in document FR 2 721 525.

 In a second solution, the upper reinforcement layer used is a flexible fabric. In this case, this layer is pressed by the expansion of the polyurethane foam under the upper protective layer. It therefore follows the variations in curvature of the internal face of the mold. Document DE 44 02 669 describes an example of such an embodiment.

 In a third solution, the upper reinforcing layer is a rigid blade (either metallic or made of polymerized fibers). In this case, this blade is suspended in the structure, at a distance from the upper protective layer and it has holes allowing the expanding foam to pass through it to press the protective layer onto the internal face of the mold.

 It is understood that the use of a complex composed of a rigid upper reinforcing layer assembled with a protective layer is incompatible with a geometry of the upper face comprising areas in relief, which have strong variations in curvature. Indeed, in this case, in the zones of strong curvatures, the upper protective layer, and therefore the upper reinforcement layer which is associated with it, being strongly curved, the mechanical properties of this reinforcement layer are markedly degraded, and the role of mechanical reinforcement is greatly reduced.

 To use a rigid reinforcement element with the technique of injecting the core in situ, it has already been proposed, and in particular in document CH 368 402, to use as upper reinforcement layer a sheet with a large perforation, which allows the passage of the polyurethane during foam expansion. It is understood that this solution which moves the upper reinforcing layer away from the upper protective layer has the drawback of reducing the rigidity of the structure. Indeed, on the one hand, because the upper reinforcement layer has very many recesses, and on the other hand, it is close to the neutral fiber of the board.

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 Document FR 2 714 842 has also described an embodiment in which the upper protective layer of the ski is itself perforated to allow the passage of a solid injected product such as solid polyurethane. This polyurethane is injected above the upper reinforcing layer between the protective layer over its major part, to come, in the indented areas, in contact with the internal surface of the upper part of the mold.

 The problem which the invention proposes to solve is that of allowing the use of an upper rigid reinforcement layer in a board, the upper face of which has areas of different levels with abrupt breaks in slope, while being compatible with a method of manufacturing the board by injecting the core in situ.

supérieure possédant au moins une région en relief, et comportant : . une couche supérieure de protection ; . une couche supérieure de renfort située sous la couche supérieure de protection, et étant collée sur cette dernière sur la totalité de sa surface ; . et un noyau obtenu par injection in situ d'une mousse de polyuréthanne. Statement of the invention
The invention therefore relates to a gliding board having a face

superior having at least one raised region, and comprising:. an upper protective layer; . an upper reinforcing layer located under the upper protective layer, and being bonded to the latter over its entire surface; . and a core obtained by in situ injection of a polyurethane foam.

 This board is characterized in that the upper reinforcing layer is formed from a rigid and full sheet. By rigid sheet is meant that it is made of a material which supports without deformation the expansion pressure of the injected polyurethane constituting the core, which is of the order of ten bars. This sheet can nevertheless be flexible, that is to say undergo deformations with large radii. By full sheet is meant that it is a continuous material, which, over its largest surface, does not allow the polyurethane to pass during the in situ injection, in contrast to openwork structures of the grid type.

 The invention relates to a gliding board having an upper face having at least one raised region, that is to say locally having a significant change in level to form either a boss, that is to say a outgrowth, or a hollow, that is to say a cavity.

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 According to the invention the upper reinforcement layer has locally cutouts located near the borders of the raised region. When the board has bosses, these cutouts form passage zones crossed by the polyurethane foam during the in situ injection. In this way, the polyurethane foam is interposed between the upper level of the upper non-deformed reinforcing layer and the lower level of the upper protective layer to form the raised area.

 In the case where the board has cavities on its upper face, the cutouts allow the passage of the upper protective layer. Thus, the upper protective layer is deformed into a hollow inside this cavity, and comes directly into contact with the polyurethane foam passing below the level of the neighboring upper reinforcing layer.

 In other words, since the upper reinforcing layer does not undergo sudden deformation, it always remains far below the limit values of elastic deformation. The mechanical characteristics of the gliding board are therefore optimized while the upper protective layer undergoes permanent deformation under the combined effect of the shape of the mold comprising cavities and / or reliefs, of the temperature making the constituent material more malleable. and the expansion pressure of the polyurethane foam.

 These cuts can be of various shapes. Thus, in a first variant, the cutouts form the closed contour of a recess in the upper layer of rigid reinforcement. In this case, the polyurethane passes through the upper reinforcing layer to come directly into contact with the upper protective layer at the level of a recess in the interior of the mold, over the whole of the raised area when it '' is about boards having bosses.

When, on the contrary, the boards have cavities, a relief situated in the mold crosses this cut to form a hollow on the board.

 In another variant, the cutouts may be present on the lateral edges of the upper reinforcing layer, the raised regions of the board being located on the edges of the latter. In other words, in certain areas, the upper reinforcing layer has a width less than that of the board,

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 which allows the polyurethane to come directly into contact with the upper protective layer, in these particular cut areas.

 In another variant, the cutouts may have a shape defining an inner tongue which is deformable with respect to the rest of the upper layer of rigid reinforcement. In other words, the partially cut region of the upper reinforcing layer is connected to the rest of said layer by a specific area of reduced size. This zone allows a certain local flexibility of the upper reinforcing layer which is essentially rigid. This cut-out zone forming a tongue moves under the effect of the pressure of the polyurethane to conform to the shape of the raised zone of the board, and thus form a boss.

 In a particular form, the upper reinforcing layer can be curved over the width of the board, that is to say either be concave or convex when the general section of the board is not rectangular, but slightly curved or up or down. This curvature is possible because it has a very large radius of curvature, in comparison with the abrupt breaks in slope that the upper face of the board can have at the borders of the raised areas.

 In a particular embodiment when the board has reliefs forming bosses, it can also include a grid of reinforcing wires located below the upper reinforcing layer, at least at the cutouts. This grid reinforces the upper rigid reinforcement layer made locally fragile in the areas where it is cut. In addition, under the very high pressure of the polyurethane, certain upper reinforcing layers may tend to move too strongly in the cut areas, this grid keeps these elements in place.

 Advantageously in practice, this grid of reinforcing wires can be pre-glued under the upper reinforcement layer.

 In practice, the sheet forming the upper reinforcing layer can be either a prepolymerized fabric of glass, carbon or aramid yarns, or else a metallic sheet, for example of steel or of an aluminum-based alloy.

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 The invention also relates to a method of manufacturing a gliding board. This process consists, in known manner, of placing in a mold, at least:. a sole, + an upper reinforcement layer, associated by bonding to an upper protective layer.

 We also proceed in a known manner, to the injection between the sole and the upper reinforcement layer, components of a polyurethane foam capable of reacting in situ by expanding to form the core of the board, by pressing in in addition to the upper reinforcement layer and the upper protective layer on the internal face of the upper part of the mold.

 This process is characterized in that a rigid and full sheet is used as the upper reinforcing layer, and that cutouts are made in said layer at the level where it is desired to form a raised area on the upper face of the board. In this way, with regard to the raised areas forming bosses, during the in situ injection, the polyurethane foam passes through the cutouts to come into contact with the upper protective layer and deform it to form the raised areas, while in the rest of the board, the upper reinforcing layer substantially retains its shape.

 In other words, firstly, localized cuts are made in the rigid upper reinforcing layer and then, secondly, the molding operation is carried out. The mold cover has a cavity at the level of the boss so that the latter occupies the corresponding volume during the injection of the polyurethane. More specifically, the boss is obtained by the plastic deformation of the upper protective layer under the effect of the foam expansion pressure as well as its temperature.

 As regards the recessed areas, the interior of the mold cover has a boss which pushes the upper protective layer inside the cutouts of the reinforcing layer.

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Brief description of the figures
The manner of carrying out the invention as well as the advantages which result therefrom will emerge clearly from the description of the embodiments which follows, in support of the appended figures in which:
Figure 1 is a top view of a ski produced according to a first embodiment.

 Figure 2 is a sectional view along a plane II-II 'of Figure 1.

 FIG. 3 is a top view of the sheet constituting the upper reinforcement layer used to obtain the ski of FIG. 1.

 Figures 4,5 and 6 are schematic sectional views respectively along the planes IV-IV ', V-V', VI-VI 'of Figure 1.

 Figure 7 is a top view of a ski produced according to an alternative embodiment.

 FIG. 8 is a sectional view along the plane VIII-VIII ′ of FIG. 7.

 FIG. 9 is a bottom view of the upper assembly comprising the protective sheet, the reinforcing layer and the grid used to obtain the skis of FIG. 7.

 10 shows a section along the plane XI-XI 'of Figure 7, of the ski shown in the injection mold before injection.

 Figures 11,12 and 13 are sectional views respectively along the planes XI-XI ', XII-XII', XIII-XIir of Figure 7.

Way of realizing the invention
As already mentioned, the invention relates to gliding boards which have an upper face having raised areas, that is to say protruding areas or hollow areas.

 Thus, the ski (1) illustrated in FIG. 1 has three protruding zones (2,3). The two zones (2) are present at the rear zone (4), on the edges of the board. They form two bosses, the ski having a thickness (e2) greater than its thickness (el) in its middle part corresponding to the body of the ski.

 On the other hand, in its front part (5), the ski (1) has a boss (3), or a protruding area at the level of the longitudinal axis (6) of the ski forming an additional thickness.

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 FIG. 2 schematically represents the upper part of a ski, in which the lower assembly comprising the sole, the edges and the lower reinforcement is not represented. At the borders of the bosses (2,3), the upper face (8) of the ski has a sudden break in slope (7,9). Such a slope (7,9) can easily be absorbed by the upper protective layer (10), which is generally made of elastomeric plastic.

 According to the invention, the ski (1) comprises an upper reinforcing layer (11) as illustrated in FIG. 3. This reinforcing layer (11) is made of a rigid material, chosen to give a certain rigidity to the board. This layer is rigid enough to withstand the pressure of the polyurethane when it expands in situ. This pressure is of the order of ten bars. The materials commonly used to make this type of reinforcement can be polymerized fabrics based on son or fibers of glass, carbon or aramid such as Kevlar. It can also be a metal sheet that can be made from an aluminum alloy such as Zicral, or even steel.

 According to the invention, this reinforcing layer (11) has cutouts (15,16) made directly above the borders of the raised areas (2,3).

 In the form illustrated in FIG. 3, the cutout (16) defines a tongue (18), which is in the illustrated form oriented towards the front (5) of the ski. This tongue (18) is connected to the rest of the reinforcing layer (11) by an area (20) of reduced width with respect to the length of the tongue (18), so that this tongue (18) has a certain flexibility with respect to the main plane of the reinforcement (11).

 In the form illustrated in FIG. 3, the upper reinforcement layer (11) also includes cutouts (15) situated directly above the lateral bosses (2) located in the rear part of the ski (1). These cutouts (15) reduce the width of the upper reinforcement layer (11). These cuts (15) can be obtained either by cutting the polymerized fabric serving as a reinforcing layer, or even by machining.

 First, the upper reinforcement layer (11) is bonded below the upper protective layer (10), then during the core injection operation (22), the expansion of the polyurethane foam exercise a

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 pressure on the upper reinforcement layer (11) and presses it against the internal wall of the mold.

 Thus, in the skate area of the ski, and as illustrated in FIG. 5, the reinforcing layer (11) occupies the entire width of the upper part of the upper protective layer (10) on the upper surface of the ski.

 In the boss area (3) as illustrated in FIG. 6, it can be seen that the tongue (18) of the upper reinforcement layer (11) is embedded in the boss (3) located in the central part of the ski. The tongue (18) is therefore located above the level of the rest of the upper reinforcement layer (11), corresponding to the level of the lateral parts (31, 32) of the reinforcement.

 Thus during the injection of the core (22), the cutout (16) formed in the upper reinforcement layer (11) creates a flexibility in bending of the tongue (18), which allows the polyurethane foam to fill. the boss (3). In this way, in the zones of very strong curvature (34, 35), corresponding to the borders of the boss (3), the upper reinforcement layer (11) is not curved and is not subjected to stresses.

 In the form illustrated in FIG. 6, the ski also comprises a grid of reinforcement wires (30), located below the upper reinforcement layer (11), and intended to limit the displacements of the lateral parts (31,32) of the reinforcing layer (11) at the level of the boss (3).

 This grid (30) can be made from glass son, or metallic son. It is pre-glued under the reinforcing layer to avoid the unexpected separation of the lateral parts (31, 32) of the reinforcing layer (11) at the level of the boss (3). When injecting the polyurethane foam, it passes through the grid (30) at the central level of the ski, and pushes the tongue (18) of the reinforcing layer into the bottom of the boss (3). The polyurethane foam then comes into contact with the edges (34, 35) of the boss.

 In the areas of the rear bosses (2), the upper reinforcing layer (11) is only present at the central level of the board due to the cutouts (15), as illustrated in FIG. 4. Thus, when the core (22) is injected, at the level of the zones

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 side (23, 24), the polyurethane comes directly into contact with the upper protective layer (10), and repels the latter to form the two lateral zones (2) protruding. Thus, although the upper face of the board has strong reliefs, and significant slope breaks, the upper reinforcement layer (11) is not deformed in these areas, it therefore retains its rigidity necessary for the optimal behavior of the ski.

 The cutouts and the relief zones can take different shapes, as illustrated in FIG. 7. Thus, such a ski (40) has, at the front part (41), a boss (42) whose contour (43) is closed. . In the rear part (44), the ski (40) has a cavity (45) whose outline (46) is also closed.

 Such raised areas can be obtained by using an upper assembly comprising an upper reinforcement layer (48), as illustrated in FIG. 9. This layer (48) has recesses (50,51) next to the raised areas (42,45). These recesses (50, 51) are obtained by cutting the contour corresponding to the raised areas and eliminating the corresponding reinforcement part.

 This reinforcing layer (48) is pre-glued to the upper protective layer (47). In addition, a reinforcing grid (60) is pre-glued at the cutouts (43) on the reinforcing layer.

 Thus, as illustrated in FIG. 10, during the manufacturing process, there is inside the mold (19) the lower assembly (17) formed of the sole, the edges and a lower reinforcement. The upper protective layer (47) and the upper reinforcing layer (48) are arranged above as illustrated in FIG. 9.

 Between the upper assembly composed of the upper reinforcing layer (48) associated with the upper protective layer (47), and the lower assembly (17) is defined the volume into which the polyurethane foam will be injected. The mold is then closed with its cover (21) which has a hollow area (25) of shape complementary to that of the future boss (42).

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 Subsequently, and as illustrated in FIG. 11, when the polyurethane of the core (22) expands, it comes into contact with the upper protective layer (47) in the zone which forms the boss (42) passing to through the recess (50) made in the reinforcing layer (48). In this zone, the polyurethane continues its expansion by pressing the upper protective layer against the corresponding face of the mold and thus creating the protuberance of the boss (42). The upper reinforcing layer (48) is thus not deformed and therefore retains all of its mechanical properties for which it was included in the structure.

 The lateral parts (54,55) of the reinforcement (48) located at the level of the boss (42) are pressed against the walls (57,58) of the upper part (21) of the mold to form the upper face of the board.

 As illustrated in FIG. 11, a grid of reinforcement wires (60) can be provided to avoid excessive deformation of the upper reinforcement layer (48) during the passage of the polyurethane in the recess (51).

 The ski according to the invention illustrated in FIG. 12, can also include other types of raised zones (62, 63) such as those presented in lateral parts of the skate zone of the ski of FIG. 7. These zones in relief are similar to the protruding areas (2) illustrated in Figures 1 and 4.

 The ski illustrated in FIG. 7 also includes, in the rear part, a recessed area (45). This recessed area is obtained during the injection of the polyurethane thanks to the presence of a protuberance (26) formed in the cover (21) of the mold. More specifically, when the polyurethane expands under the upper protective layer (47) and the upper reinforcing layer (48), it pushes the latter against the bottom of the mold cover (21). Thus, at the level of the recess (51), the polyurethane foam of the core comes directly into contact with the central zone (69) of the upper protective layer (47) and presses the latter against the protuberance (26) of the cover. of the mold (21). The lateral parts (65,66) of the reinforcing layer (48), and the lateral parts (67,68) of the upper protective layer are pushed back to a level higher than that of the cavity.

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 Obviously, the positions and the geometry of the different raised areas can be adapted according to the type of board to be produced, and are in no way limited to the positions and shapes illustrated.

 It appears from the foregoing that the gliding boards produced in accordance with the invention combine both good mechanical resistance due to the presence of the characteristic upper reinforcement layer, while allowing large deformations of the upper face of the board. , for a type of ski of reduced cost having an injected core.

Claims (14)

 . and a core (22) obtained by in situ injection of a polyurethane foam, characterized in that the upper reinforcement layer (11) is formed from a rigid and full sheet and in that said upper reinforcement layer (11) has cutouts (15,16) located at the borders of the raised region (2,3).

 CLAIMS 1 / Gliding board (1) having an upper face (8) having at least one raised region (2,3), and comprising:. an upper protective layer (10); + an upper reinforcing layer (11) located under the upper protective layer (10), and being bonded to the latter over its entire surface; 2 / Gliding board according to claim 1, characterized in that these cutouts form passage zones crossed by the polyurethane foam during the injection in situ, so that said foam comes, by exerting a push under this part of the lower face of the upper protective layer (10), forming a raised boss (3) passing above the level of the neighboring reinforcing layer (11). 3 / Gliding board according to claim 1, characterized in that inside the cutouts, the upper face of the board has a hollow region (45) inside which the upper protective layer (47) comes directly into contact with the layer of polyurethane foam passing below the level of the neighboring upper reinforcement layer (65,66). 4 / Gliding board according to claims 2 and 3, characterized in that around the cutouts (15,16) the bonding of the upper reinforcing layer (11) on the upper protective layer (10) is hermetic in order to avoid polyurethane infiltration. 5 / board according to claim 1, characterized in that the cutouts (43,46) form the closed contour of a recess (50,51) of the upper rigid reinforcement layer (48). <Desc / Clms Page number 14> 6 / board according to claim 1, characterized in that the cutouts (15; 64, 65) are present on the side edges of the upper rigid reinforcement layer (11; 48), and in that the raised regions (2 ; 62,63) are located on the edges of the board. 7 / board according to claim 1, characterized in that the cutouts (16) have a shape defining an inner tongue (18) deformable relative to the rest of the upper layer of rigid reinforcement (11). 8 / board according to claim 1, characterized in that the upper reinforcing layer is curved over the width of the board. 9 / board according to claim 1, characterized in that it also comprises a grid (30) of reinforcing son located below the upper reinforcement layer (11), at least at the cutouts. 10 / board according to claim 9, characterized in that the grid of reinforcing son is pre-glued under the upper reinforcement layer. 11 / board according to claim 1, characterized in that the sheet forming the upper reinforcing layer is a prepolymerized fabric of glass, carbon or aramid son. 12 / board according to claim 1, characterized in that the sheet forming the upper reinforcing layer is a metal sheet. 13 / Process for manufacturing a gliding board, consisting of:

 . to have in a mold at least: 0 a sole, 0 an upper reinforcement layer, associated by bonding to an upper protective layer,. then injecting between the sole and the upper reinforcement layer the components of a polyurethane foam capable of reacting in situ by expanding to form the core of the board by plating the upper reinforcement layer and the upper protective layer on the internal surface of the upper part of the mold, <Desc / Clms Page number 15>  characterized in that a rigid and full sheet is used as the upper reinforcing layer, which is cut out in the said layer at the level where it is desired to form a raised area on the upper face of the board, so that during the injection in situ, the polyurethane foam comes by exerting a push under the upper protective layer, forming a raised boss passing above the level of the upper layer of resident reinforcement. 14 / Process for manufacturing a gliding board, consisting of:

 + to place in a mold at least: 0 a sole, 0 an upper layer of reinforcement, associated by bonding to an upper layer of protection, + then to inject between the sole and the upper layer of reinforcement the components of a foam of polyurethane capable of reacting in situ by expanding to form the core of the board by plating the upper reinforcing layer and the upper protective layer on the internal surface of the upper part of the mold, characterized in that one uses as upper reinforcing layer a rigid and full sheet, which is made in said layer cutouts at the level where it is desired to form a hollow area on the upper face of the board, so that during the injection in situ , a protuberance present in the mold cover passes through said cutouts while, the pressure exerted by the expanding polyurethane keeps the upper reinforcing layer pressed against the bottom of the mold. e the upper part of the mold.