EP0650747A1 - Method for molding a ski - Google Patents

Abstract

Method for moulding a ski in a single stage, consisting: . in depositing at least one layer of inner reinforcement (13, 14) in the bottom of a mould; . in positioning an upper reinforcement layer (22) composed of mechanisation elements over this lower assembly (10); . in placing a protective and decorative layer (21) over this upper reinforcement layer (22); . in closing the cover (lid) of the mould; . in injecting a fluid intended to expand the various elements against the walls, between the lower assembly (10) and upper assembly (22); characterised in that at least one additional element (30) intended to vary the relative position of the mechanisation elements of the said reinforcement layer (22) with respect to the faces of the ski is positioned at the level of the upper reinforcement layer (22). <IMAGE>

Description

Technical area

The invention relates to a new method for manufacturing a shaped ski.

It relates more particularly to an improved process for manufacturing a ski in a single step, intended to receive various materials, capable of communicating properties specific to skiing; it relates more particularly to an improved process of the type in question, in which the relative position of the upper reinforcement can be varied relative to the outer surface of the ski.

Prior Techniques

In document US-A-4 725 070, a process has been described for the manufacture of a ski, which takes advantage of the thrust obtained in situ by the expansion of the foam during the injection of the reactive compounds intended to form this foam, to press against the walls of the mold the various assemblies intended to form the envelope and the sliding surface of the ski.

• à déposer dans le fond d'un moule en deux parties, respectivement un fond et un couvercle, un premier ensemble destiné à former l'enveloppe inférieure formant la surface de glisse;
• à positionner sur ce premier ensemble inférieur un second ensemble supérieur destiné à former l'enveloppe supérieure formant les chants et le dessus;
• à intercaler entre les faces en regard de ces deux ensembles, une couche étanche destinée à définir une gaine déformable;
• à fermer le couvercle sur le fond du moule ainsi rempli
• à injecter dans cette gaine un fluide destiné à expanser les deux ensembles jusqu'à venir les plaquer contre les parois du moule;
• et enfin, à refroidir et à ouvrir le moule pour retirer le ski ainsi obtenu.

In document EP-B-0 430 824, the Applicant has described a process for the manufacture of a shaped ski in a single phase, consisting of a body surrounded by a peripheral envelope produced in two parts, respectively lower and which consists essentially of:

• depositing in the bottom of a mold in two parts, respectively a bottom and a cover, a first assembly intended to form the lower envelope forming the sliding surface;
• positioning on this first lower assembly a second upper assembly intended to form the upper envelope forming the edges and the top;
• inserting between the facing faces of these two assemblies, a sealed layer intended to define a deformable sheath;
• to close the lid on the bottom of the mold thus filled
• injecting into this sheath a fluid intended to expand the two assemblies until they are pressed against the walls of the mold;
• and finally, to cool and open the mold to remove the ski thus obtained.

The method advantageously makes it possible to produce a shaped ski in a single step, in particular when the upper assembly consists of a single shell forming a layer of protection and decoration.

To obtain reliefs on the top of the ski, it has been proposed to vary the thickness of the protective layer at the desired locations. This solution weighs down the ski and requires manufacturing in several stages.

To obtain these same reliefs, in the Applicant's method described above, it is possible to provide corresponding cavities in the walls of the cover. Unfortunately, during the pushing, the fibrous reinforcement of the upper envelope undergoes in this cavity deformations in different directions, which weaken and often even can cause the rupture of this fibrous reinforcement, and consequently, cause a significant loss of mechanical characteristics sought.

• . tout d'abord, à fixer sur la face interne du couvercle d'un moule, un noyau rigide, par exemple en bois, en nid d'abeilles, en mousse ou en métal, destiné à former partie du corps, puis à placer sur le dessus d'un fond de moule épousant la section du ski, l'ensemble supérieur destiné à former les chants et le dessus, cet ensemble supérieur comprenant en outre un matériau de remplissage en matière plastique, apte à fluer dans les espaces libres du fond du moule lors de la fermeture du moule;
• . puis, à rapprocher le couvercle du fond ainsi rempli, de manière à ce que le noyau rigide formant poinçon plaque par poussée l'ensemble contre les parois du moule, tout en faisant fluer le matériau de remplissage qui comble ainsi les espaces vides;
• . et enfin, à détacher l'ensemble obtenu pour le placer, dans une seconde phase, sur un ensemble inférieur préalablement réalisé, destiné à former la semelle de glisse.

In document FR-A-2 611 519, a method of manufacturing the ski in several distinct phases has been described, which consists of:

• . first, to fix on the internal face of the cover of a mold, a rigid core, for example in wood, honeycomb, foam or metal, intended to form part of the body, then to place on the top of a mold base conforming to the ski section, the upper assembly intended to form the edges and the top, this upper assembly further comprising a plastic filling material, capable of creeping into the free spaces of the base of the mold when closing the mold;
• . then to bring the cover closer to the bottom thus filled, so that the rigid core forming the punch pushes the assembly against the walls of the mold, while causing the filling material to flow, thereby filling the empty spaces;
• . and finally, detaching the assembly obtained to place it, in a second phase, on a lower assembly previously produced, intended to form the gliding sole.

This technique remains expensive, since it requires the use of at least two distinct phases, namely the manufacture of the body and its assembly with the lower assembly forming the sole. In addition, this technique requires the use of a rigid core previously made, to serve as a punch.

In the additional document FR-A-2 620 628, the walls of the bottom of the mold have a recess or a projection which, when the mold is closed, can be partially filled (see FIG. 14) by an attached plate, in particular by a visco-elastic material, inserted prior to punching between the sheet intended to form the shell and a fibrous reinforcement. However, since the filling of this cavity is essentially ensured by the pushing effect of the rigid core on a together itself resting against the rigid walls of the mold, filling the hollow with the visco-elastic plate is a delicate operation, in particular due to the risks of inclusion of air, formation of small cavities, which can cause defects, in particular of heterogeneity of the ski at this place. The manufacture of these skis is always carried out in several distinct stages and therefore remains expensive. In addition, if this technique makes it possible to position an added plate in a cavity, on the other hand, it does not make it possible to position reinforcing elements inside the ski with respect to the faces of the ski, except for pre-machining the core and use thick filler layers.

The invention overcomes these drawbacks. It relates to a method of manufacturing a ski in a single step of molding and forming, which makes it possible to produce skis whose edges and the top can have complex shapes, such as reliefs, and whose mechanization elements can be arranged in desired locations relative to the faces of the ski, to obtain specific characteristics.

The invention relates more particularly to a single-step process, in which the faces of the ski have varied reliefs without the internal fibrous reinforcing elements matching the accentuated forms of these reliefs.

The invention also relates to a method for producing a ski in a single step, in which the reinforcing elements are positioned relative to the neutral fiber of the ski, in order to obtain suitable characteristics in predetermined locations.

Statement of the Invention

• . à déposer dans le fond d'un moule en deux parties, respectivement un fond et un couvercle, un ensemble inférieur comportant une surface de glisse, des carres et au moins une couche de renfort inférieure ;
• . à positionner sur cet ensemble inférieur, une couche de renfort supérieure composée d'éléments de mécanisation ;
• . à placer sur cette couche de renfort supérieure (22) une couche de protection et de décoration, destinée à former les trois autres faces du ski, à savoir au moins une partie des chants et le dessus, tout en formant une cavité ;
• . à fermer le couvercle sur le fond du moule;
• . à injecter dans la cavité formée entre l'ensemble inférieur et la couche de renfort supérieure, un fluide destiné à expanser les différents éléments contre les parois du moule;
• . et enfin, à refroidir et à ouvrir le moule pour retirer le ski obtenu,

se caractérise en ce que, au niveau de la couche de renfort supérieure, on positionne au moins un élément additionnel destiné à faire varier la position relative des éléments de mécanisation de ladite couche de renfort par rapport aux faces du ski.This process for the manufacture of a shaped ski, in a single step simultaneously ensuring the forming and the molding, which consists:

• . depositing in the bottom of a mold in two parts, respectively a bottom and a cover, a lower assembly comprising a sliding surface, edges and at least one lower reinforcing layer;
• . positioning on this lower assembly, an upper reinforcing layer composed of mechanization elements;
• . placing on this upper reinforcing layer (22) a protective and decorative layer, intended to form the three other faces of the ski, namely at least part of the edges and the top, while forming a cavity;
• . closing the cover on the bottom of the mold;
• . injecting into the cavity formed between the lower assembly and the upper reinforcing layer, a fluid intended to expand the various elements against the walls of the mold;
• . and finally, to cool and open the mold to remove the ski obtained,

is characterized in that, at the level of the upper reinforcement layer, at least one additional element is positioned intended to vary the relative position of the mechanization elements of said reinforcement layer relative to the faces of the ski.

In a preferred embodiment, the invention consists, in a method of manufacturing the ski in a single step by pushing effect during the expansion of the filling foam, to be provided on the walls of the cover, and no longer on the bottom of the mold, at least one relief, then filling this relief with a plate of an appropriate material during the gradual expansion of the foam forming the heart. In this way, the positioning of the plate is carried out gradually and with precision, which avoids the risks of inclusion of air, formation of small cavities and ruptures of the fibrous reinforcing element, and gives the whole a good homogeneity.

• l'élément additionnel est déposé entre les couches de mécanisation de la couche de renfort supérieure;
• l'élément additionnel caractéristique est déposé au-dessus des couches de mécanisation ;
• la face supérieure du ski présente un relief définissant une cavité sur la face interne de la couche de protection, et l'élément additionnel vient combler la cavité laissée entre la couche de protection et les couches de mécanisation, de manière à éviter toute cassure des fibres constituant ces couches fibreuses de mécanisation ;
• cette cavité est ménagée sur la paroi interne du couvercle destinée à définir le dessus du ski, notamment juste en aval de la partie destinée à former la spatule et en amont de la zone du patin, c'est-à-dire dans la partie où est généralement positionné l'ensemble amortisseur de vibrations ;
• la plaque est en un matériau choisi dans le groupe comprenant les matières plastiques rigides, le bois, les métaux, les matériaux composites, d'usage courant dans la fabrication des skis ; ce peut être également une enveloppe fermée contenant un fluide (eau, huile, air) ;
• la plaque est en un matériau viscoélastique, éventuellement associée à une plaque de contrainte;
• le fluide d'expansion est de l'air ou une résine de collage moussante ou non ;
• le fluide d'expansion est constitué par un mélange de réactifs destinés à former in-situ une mousse de matière plastique de remplissage, notamment en polyuréthanne ou en polyester, de sorte que l'ensemble, contrairement à l'état de la technique visé dans le préambule, ne comporte plus de noyau rigide;
• la couche de protection et de décoration est une coque unique épousant la forme du ski.

Advantageously, in practice:

• the additional element is deposited between the mechanization layers of the upper reinforcement layer;
• the characteristic additional element is deposited above the mechanization layers;
• the upper face of the ski has a relief defining a cavity on the internal face of the protective layer, and the additional element fills the cavity left between the protective layer and the mechanization layers, so as to avoid any breakage of the fibers constituting these fibrous mechanization layers;
• this cavity is formed on the internal wall of the cover intended to define the top of the ski, in particular just downstream of the part intended to form the tip and upstream of the pad area, that is to say in the part where is generally positioned the vibration damper assembly;
• the plate is made of a material chosen from the group comprising rigid plastics, wood, metals, composite materials, commonly used in the manufacture of skis; it can also be a closed envelope containing a fluid (water, oil, air);
• the plate is made of a viscoelastic material, possibly associated with a stress plate;
• the expansion fluid is air or a foaming bonding resin or not;
• the expansion fluid consists of a mixture of reagents intended to form a foam of plastic filling material in situ, in particular of polyurethane or polyester, so that the assembly, unlike the state of the art referred to in the preamble no longer has a rigid core;
• the protective and decorative layer is a unique shell conforming to the shape of the ski.

In a practical embodiment, the top of the ski has a relief defining an internal cavity, and this cavity is filled by the characteristic plate formed by a damping assembly constituted by a rigid plate of constraints, having a modulus of elasticity E greater than 10,000 MPa and having a thickness of between 0.5 and three millimeters, preferably of the order of one millimeter; as rigid plate with high modulus of elasticity, aluminum alloys, aluminum / zinc / magnesium alloys are advantageously used, in particular of the type of those which are marketed by the company CEGEDUR-PECHINEY under the registered trademark "ZICRAL" , or thermosetting laminated or thermo-plastic materials reinforced with glass or carbon threads. This stress plate is associated with a layer of a visco-elastic material having a thickness of between 0.5 and two millimeters, preferably close to one millimeter, commonly used in the manufacture of skis, for example butyl rubber, synthetic elastomer, alone, mixed or loaded. Thus, the stress plate and the visco-elastic layer have optimum damping effects, which does not make it possible to obtain the embodiment illustrated in FIG. 14 of document FR-A-2 620 628 cited in the preamble.

The characteristic relief of the invention can be placed both on the edges and on the top of the ski. It is advantageously positioned at a vibration belly, especially just downstream of the spatula and upstream of the skate area. This relief can also be positioned just in the center of the skate area, so as to give extra thickness in this sector.

In a practical embodiment, there is inserted, just before injection, between the two fibrous reinforcing elements respectively lower and upper, a flexible waterproof membrane, such as for example a sheath, of a stretchable plastic material, in which injects the fluid intended to push these elements against the walls of the mold.

Brief description of the drawings

The manner in which the invention can be implemented and the advantages which ensue therefrom will emerge more clearly from the embodiment which follows, supported by the appended figures.

Figure 1 is a schematic sectional representation of a mold, shown in the open position, equipped in accordance with the invention.

Figure 2 is a schematic representation of the same mold in the closed position.

Figure 3 is a longitudinal sectional representation of a ski according to the invention.

Figure 4 is an improved embodiment of a mold in the closed position according to a preferred embodiment of the invention (with cavity).

FIG. 5 is a schematic representation in summary perspective of a ski according to a mode of the invention, shown in section in FIG. 6 along the axis VI-VI ′ of FIG. 5.

Way of carrying out the Invention

The mold comprises (see Figures 1 and 2) two parts, respectively a bottom (1) and a cover (2), whose inclined side walls (4,5) are intended to form the edges, and whose horizontal upper wall ( 3) forms the top of the ski.

• . un matériau fibreux de renfort supérieur (22), constitué d'une nappe textile préimprégnée d'une résine thermodurcissable, par exemple époxyde;
• . une coque thermoplastique (21) de protection par exemple en résine ABS présentant un décor sur l'extérieur.

The bottom (1) has a housing (7) intended to receive a first assembly (10) intended to form the lower assembly forming the sliding surface. This assembly comprises the sole proper (11), the two edges (12 and 12 ') and fibrous reinforcing elements (13) lower, respectively (13 and 14), pre-impregnated with a thermosetting resin, for example epoxy . As taught in document EP-B-0 430 824 of the Applicant cited in the preamble, on this first lower assembly (10), a second assembly is positioned intended to form the upper envelope, and comprising in order:

• . an upper reinforcing fibrous material (22), consisting of a textile sheet impregnated with a thermosetting resin, for example epoxy;
• . a thermoplastic shell (21) for protection, for example made of ABS resin, with a decoration on the outside.

In the cavity space (50) delimited by the two lower (14) and upper (22) reinforcements, and the shell (21), a sealed sheath is inserted, designated by the reference (25), tubular, made of plastic material stretchable, laid flat on the lower assembly (10).

According to a characteristic of the invention, an additional plate (30) is positioned on top of the upper reinforcing fibrous element (22), which may or may not be temporarily secured by any known means, such as sewing, gluing or other. This rigid plate (30), for example made of metal, takes on the shape of a half-moon (see figures), so as to avoid sudden deformation of the fibers of the reinforcing fibrous material (22), sudden deformation, which, as we as is known, causes fiber breakage and, consequently, deterioration of the mechanical properties.

Once all these elements in place, the mold is closed (Figure 2), then injected into the sheath (25) the constituents of a polyurethane foam, namely an isocyanate and a polyol. In known manner, these components react with each other and expand in situ, causing the progressive plating of the upper assembly against the walls (3,4,5) while causing the adhesion of the various constituents to each other and to the foam (26) thus formed. During expansion, the characteristic plate (30) then gradually comes into place against the internal face of the shell (21), itself pressing against the internal face of the top (3) of the cover (2). In this way, the upper fibrous reinforcement (22) comes into place in the desired position relative to the top of the ski.

Thus, thanks to the curvature of the internal face of the additional element (30) and to its dimensions, it is possible to modify the relative positioning of the upper reinforcement (22) of the ski both relative to the top of the ski, and especially by compared to its neutral fiber.

In an advantageous form shown in FIG. 3, this rigid additional element is located longitudinally in the tip (30) and / or heel (30 ') zones, to modify the flexibility of the ski.

In an advantageous embodiment shown in FIG. 4, the horizontal internal wall (3) of the cover (2) has a cavity designated by the reference (6). During expansion, the characteristic plate (30) then gradually comes into place in the cavity (6) until it is completely filled, since its shape and its positioning on the fibrous reinforcing element (22) correspond exactly to those of said cavity (6). Furthermore, once in place, this additional element (30) locally modifies as previously, the relative position of the upper reinforcement (22) relative to the neutral fiber.

In a particular embodiment illustrated in Figures 5 and 6, the filling plate of the cavity (6) forming the relief (40), is constituted by a damping assembly formed on the top in contact with the internal part of the relief (40 ) a stress plate (41), such as for example an aluminum / zinc / magnesium alloy marketed by CEGEDUR / PECHINEY under the brand "ZICRAL", having a modulus of elasticity of 12,000 MPa and a thickness of a millimeter. This constraint plate (41) is associated with a sheet (42) with a high damping coefficient, the two internal and external faces of which, respectively, have been previously coated with an adhesive layer to promote the joining with the constraint plate ( 41) and with the fibrous reinforcing element (22). This visco-elastic sheet (42) of butyl rubber has a thickness of one millimeter and a damping coefficient at 25 ° C, between 0.4 and 1.2, preferably 0.6 and 0.8.

This arrangement simplifies the installation of the damping element which thus is no longer attached to the top of the ski as described in document FR-A-2 611 519 of the Applicant, but is integrated into the ski.

In the embodiment illustrated in Figure 6, the shell (21) has curved side edges (45,46). These edges arranged parallel to the sole (11), bear on the end of the upper reinforcing element (22) and this assembly in turn is supported on edges (47,48) of rigid plastic. These edges (47,48) rest on the edges of the lower element of the ski, and more precisely on the lower reinforcement (13,14) bearing on the edges (12,12 ').

• la simplification de fabrication puiqu'on opère en une seule phase;
• la possibilité de communiquer des propriétés spécifiques à des endroits déterminés, tout en ménageant la disposition sensiblement linéaire des renforts fibreux, évitant par là des causes de rupture.

The skis according to the invention have numerous advantages over those known, and in particular those mentioned in the preamble. We can cite :

• simplification of manufacturing puiqu'on operates in a single phase;
• the possibility of communicating specific properties at determined locations, while sparing the substantially linear arrangement of the fibrous reinforcements, thereby avoiding causes of rupture.

Claims (9)

1 / Method for the manufacture of a shaped ski in a single step simultaneously ensuring the forming and the molding, which consists: . to deposit in the bottom of a two-part mold, respectively a bottom (1) and a cover (2), a lower assembly (10) comprising a sliding surface (11), edges (12,12 ') and at least one lower reinforcing layer (13,14); . positioning on this lower assembly (10), an upper reinforcing layer (22) composed of mechanization elements; . placing on this upper reinforcing layer (22) a protective and decorative layer (21) intended to form the three other faces of the ski, namely at least part of the edges and the top, while forming a cavity (50 ); . closing the cover (2) on the bottom (1) of the mold; . injecting into the cavity formed (50) between the lower assembly (10) and the upper reinforcing layer (22), a fluid intended to expand the various elements against the walls (3,4,5); . and finally, to cool and open the mold to remove the ski obtained, characterized in that, at the level of the upper reinforcing layer (22), at least one additional element (30) is positioned intended to vary the relative position of the mechanization elements of said reinforcing layer (22) relative to the faces ski. 2 / A method according to claim 1, characterized in that the additional element (30) is deposited between the mechanization layers of the upper reinforcement layer (22). 3 / A method according to claim 1, characterized in that the additional element (30) is deposited above the mechanization layers (22). 4 / A method according to claim 1, characterized in that the protective and decorative layer is a single shell (21) thermoplastic conforming to the shape of the ski. 5 / A method according to claim 1, characterized in that the upper face of the ski shell has a relief (40) defining a cavity (6) on the inner face of the protective layer (21), said additional element (30 ) filling this cavity (6) by modifying the relative position of the upper fibrous reinforcing element (22) relative to the top of the ski, without breaking the fibers of this element (22). 6 / A method according to claim 5, characterized in that the cavity (6) is formed on the internal wall (3) of the cover (2) intended to define the top of the ski, just downstream of the part intended to form the tip. and upstream of the pad area, that is to say in the part where the vibration damper assembly is generally positioned. 7 / A method according to claim 1, characterized in that the additional plate (30) is made of a material chosen from the group of materials, commonly used in the manufacture of skis, including plastics, wood, metals, composite materials and visco-elastic materials. 8 / A method according to claim 1, characterized in that the expansion fluid consists of a mixture of reagents intended to form in-situ a foam of plastic filling material (26). 9 / A method according to claim 8, characterized in that the additional element consists of a stress plate (40) associated with a layer (41) of a visco-elastic material.

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