EP1224114B1 - Subassembly designed to produce an aquatic gliding board and its manufacturing process - Google Patents

Abstract

The sub-assembly comprises a hollow inner shell (7) made from resin-impregnated fibres with optional reinforcement or support, covered with a layer (8) of a high-density foam which can be reinforced locally by a plastic or cardboard honeycomb structure. The shell has a wall thickness of 0.1 - 2 mm; the foam has a density of 50 - 70 kg/cu m and is 3 - 20mm thick.

Description

The invention relates to a subassembly provided for producing a float glide on water including a surf float.

It also relates to a method of manufacturing such a subassembly and a float made from the subset in question.

In the traditional way, a surf float is made from a foam cake, especially polyurethane foam, which is formed in a mold. The mousse bread is machined by planing and sanding on a thin layer to locally customize its shape then it is coated with a fiberglass casing impregnated with resin that forms an outer reinforcing shell and gives the float its final shape. A decoration and a icing give the float its final appearance.

In some cases, the foam bread is cut longitudinally into two parts which are then glued against a wooden slat that strengthens its structure and imposes on it a predetermined longitudinal camber.

The disadvantage of such a construction technique is the weight of the float in the end. In Indeed, the foam is relatively dense, typically its density is 50kg / m3. And it is not possible in principle to reduce the density of the foam without harming the mechanical characteristics of the float.

According to another technique of construction resulting from the windsurfing, one starts from a bread relatively low density foam that is milled so as to shape it. We covers this bread with a fiberglass skin impregnated with resin. We report around this subassembly a foam envelope of higher density. Then we apply tablecloths resin-impregnated glass fibers to form the outer shell.

Such a construction mode allows a weight gain of about 20% or more while keeping a good rigidity under the feet. However, its implementation is relatively complex. In addition the central foam roll is generally made of polystyrene foam. This material has the defect of taking water. It happens that during its existence the float is struck against a reef or a rock. If the outer shell is damaged, we run the risk to have infiltrations of water, the water weighing the float and being particularly difficult to clear out.

Finally, it is known to make hollow floats with sandwich skins. Or we produces two half-shells which are then assembled together, for example in US-A-4 964 825, which corresponds to the preamble of claim 1, or else all in a closed mold with an internal bladder that is inflated to grow and apply the sandwich skins against the walls of the mold.

This manufacturing technique makes it possible to produce light boards. However, he It is not possible to customize the shape of the float. In this case the shape of the hull external depends exclusively on the shape of the mold.

An object of the invention is to propose an improved subassembly which makes it possible to realize lighter surf floats while retaining a customizable shape, or more bulky for equal weight.

This object is achieved by a structural subset as defined by claim 1.

The float is characterized by the fact that it comprises the previously defined set covered with at least one sheet of resin impregnated fibers.

The invention also relates to a manufacturing method as defined by claim 11.

La figure 1 est une vue de dessus d'un flotteur de surf.

la figure 2 est une vue de côté du flotteur de la figure 1.

La figure 3 est une vue en section transversale d'un flotteur réalisé conformément à la technique antérieure.

La figure 4 représente, en section transversale, le sous-ensemble structurel selon un premier mode de mise en oeuvre de l'invention.

La figure 5 est une vue en section longitudinale du flotteur réalisé à partir du sous-ensemble de la figure 4.

La figure 6 représente le même flotteur en coupe transversale.

La figure 7, 8 et 9 sont des vues en section transversale illustrant trois variantes de mise en oeuvre de l'invention.

Les figures 10 à 13 illustrent en section transversale une quatrième variante de réalisation de l'invention dans laquelle le sous-ensemble structurel est réalisé sous la forme de deux demi-coques.

The invention will be better understood by reference to the description below and attached drawings attached thereto.

Figure 1 is a top view of a surf float.

Figure 2 is a side view of the float of Figure 1.

Fig. 3 is a cross-sectional view of a float constructed in accordance with the prior art.

FIG. 4 represents, in cross-section, the structural subset according to a first embodiment of the invention.

FIG. 5 is a view in longitudinal section of the float made from the subset of FIG. 4.

Figure 6 shows the same float in cross section.

Figure 7, 8 and 9 are cross-sectional views illustrating three alternative embodiments of the invention.

Figures 10 to 13 illustrate in cross section a fourth embodiment of the invention wherein the structural subassembly is formed in the form of two half-shells.

Referring to FIGS. 1 and 2, in a known manner, a surf float presents itself as an elongate board with a central portion 2, a tapered front spatula and slightly raised 3, and a rear heel 4 slightly raised and with a decreased width.

In the traditional way, as shown in FIG. 3, the float is made from of a foam roll 5, typically 50 kg / m3 density polyurethane foam, which is covered with a ply 6 of fibers coated with resin. Usually, the foam bread is manufactured in mold, and it is available according to different models of length, width, volume and a variable camber. Once chosen by the manufacturer, the mousse bread is put to the desired final shape by local planing on a thin layer, and then only, it receives its outer coating. This coating increases the characteristics mechanical foam, and also protect the foam bread.

Figures 4 and 5 show, respectively in cross section and in section longitudinal, a structural subset of the float according to the invention, that is to say the subset which is located under the outer coating of the final float.

According to this first embodiment of the invention, the subassembly is formed by an inner shell 7 which is coated with a foam envelope 8.

The inner shell is hollow. This is a structural element for example made in fiberglass, carbon fiber or other synthetic material impregnated with resin, resin polyester, epoxy or other.

For example, the inner shell is made with a thickness of between 0.15 and 0.2 millimeters, or between 0.10 and 0.25 millimeters, or even more according to the intended use for the float and the type of resin used. In some cases and depending on the material used, the thickness can reach 1 to 2 millimeters.

The inner shell can be made according to different techniques. For example, she is formed around a central core made of polystyrene beads glued with vinyl glue which is then dissolved in hot water. Other types of dissolvable mandrels can be used or even an inflatable bladder.

According to another embodiment technique, the shell is made in several parts assembled together. For example the shell can be made from two half-shells (or half-shells) that fit one into the other. Both parties are assembled by gluing or any other suitable means. Other possibilities still exist.

The shell 7 can also be constructed of other materials than fibers impregnated with resin, for example a thermoplastic material, filled thermoplastic of fibers, of fibers with a polyester matrix, of stamped metal or any other material with high elastic modulus.

The shell is coated with an envelope 8. The envelope is foam, but different types of foams can be used. One can for example use a PVC foam relatively dense, with a density of 50 to 70 kg / m3. We can also choose to use less dense foams, for example polyurethane foams of about 50 kg / m3. We can also use polystyrene foams (extruded or expanded) from 30 to 50 kg / m3 or more polyetherimide foams or any other waterproof foam.

The thickness of the envelope is determined to allow a subsequent machining of this subset on this thin layer while having in the end a subset resistant and lightweight. For example, the thickness is between 3 and 15 millimeters or even 20 millimeters. Optionally, a greater thickness can be provided along the lateral edges and front / rear of the subassembly, and lower on the top and bottom. We can also provide different thicknesses on the top and bottom, on the front and back.

To make the foam envelope, we just stick foam plates that we curve to the shape of the shell by applying a pressure, for example under vacuum leaving inside the shell at atmospheric pressure so as not to distort this shell. An alternative is to place the shell in the center of a mold in which the foam is injected, or to sink or spray this foam on the shell and leave it to expand in the open air. The polymerization of the foam ensures its superficial cohesion with the shell. A primer can be applied to the surface of the shell to improve performance.

The subassembly thus produced has the advantage of being lightweight and resistant. Indeed, as the inner shell 7 is hollow, we obtain a significant weight saving by compared to a traditional mousse bread.

It is more resistant than a traditional foam bread considering its structure, with the inner shell and the relatively dense foam envelope. Both elements intervene in a complementary way, the shell by its own resistance and by the effect of closed shell, and the foam by its own resistance and the effect of spreading stresses that it produces on the surface of the shell and the core role in the final sandwich after contribution of the last superficial layer.

In addition, thanks to the previously mentioned weight gain, one can choose a foam more resistant and denser than a traditional foam while maintaining a weight significantly lower than that of a traditional float.

In addition, thanks to the low thickness of foam used and the support of the shell, can locally reinforce the surface under the feet by the addition of a nest structure bee (plastic, cardboard, aluminum ...) at the time of the realization of the foam.

Other filling materials, such as wood, or overall any material of density less than 1.

The subassembly can be machined in the same way as a traditional foam roll, according to the desire of the manufacturer, provided that the machining thickness remains less than the thickness of the the foam.

As for traditional breads, the invention provides for making several models of structural subassemblies with length, width, volume and camber variable. However, the same shell model can be used for several models of board, and play on the shape and thickness of the foam wrap to get the shapes final desired.

Finally, once shaped, the structural subset with its layer of foam machined 8 'is intended to be covered with a ply 9 of glass fibers or other coated with resin, and to receive finishing operations in the same way as for a float traditional. This is shown in FIG.

During its use, since the inner shell is hollow, a user will have less problem to evacuate the water which will be infiltrated if necessary as a result of a shock thanks in particular to the incorporation of a drain screw. In this regard, we can predict inside the shell an inflated bladder that reduces the penetration of water inside the shell. This bladder can even be inflated with a gas lighter than air, for example Helium, to further lighten the structure.

Figure 7 relates to an alternative embodiment of the invention. According to this variant, the inner shell 10 is reinforced by a central partition 11. Such a partition is used routinely especially for long floats, in order to give them a determined camber and better longitudinal rigidity.

In this case, the central partition 11 is for example foam or wood. She extends over the length of the shell. The shell 10 is formed around this partition. Optionally, the partition is lined with two layers 13 and 14 of fibers impregnated with resin, which connect continuously with the wall of the shell.

As in the previous case, the shell 10 is coated with a foam envelope 12.

FIG. 8 relates to another variant, in which the upper wall of the shell 15 is supported by a foam plate 16 previously curved.

To make the subassembly, for example, the plate 16 is shaped by thermoforming or any other suitable technique.

At first, the lower wall of the shell, on which in place the plate 16.

Then, we complete the shaping of the shell by covering the plate 16 with the fiber web impregnated with resin, then the foam envelope 17 is formed.

This plate 16 improves the resistance to driving of the upper part of the subassembly, that is to say under the feet of the surfer.

According to the variant illustrated in FIG. 9, the plate 18 is in two parts 18a, 18b which join at the level of a central partition 19 of the same nature as the partition 11. As in the previous case, the shell 20 is closed above the plate 18 and the envelope 21 is formed around the shell 20.

FIGS. 10 to 13 show another embodiment variant of FIG. the invention in which the structural subassembly is made from two half-shells assemblies. The subassembly can thus be formed of an upper half-shell 22, which will form the bridge of the final float, and a lower half-shell 24 which will form the hull. Each half-shell is formed of a foam plate 26, 28 which is first thermoformed in a mold then covered, on an inner face 30, 32, with at least one layer of fabric impregnated with resin. Advantageously, the lamination operation of the inner face 30, 32 half-shells 22, 24 will be made under vacuum while the foam plate previously thermoformed 26, 28 is still in the thermoforming mold, so that the layer of Resin-coated fabric hardens on the blister plate while it is still pressed against the mold. This ensures the best shape of the front half-shell assembly.

When the two half-shells 22, 24 are assembled to one another, for example by bonding, we obtain directly on the one hand the rigid internal shell 7, which is formed by the layers of resin-coated fabrics disposed on the inner faces of the half-shells, and on the other hand the envelope of external foam capable of being machined 8. The foams used are for example extruded polystyrene foam plates with a density of about 30 to 50 kg / m3.

For the implementation of this variant, it may be interesting to provide that one of the half-shells, for example the lower half-shell 24, is also laminated on its face outside 34 before assembling the two half-shells. The half-shell thus laminated on its two faces 32, 34 is then particularly rigid during assembly with the other half-shell, which makes it possible to better control the precision of the assembly, and therefore the precision of the shape of the subset. Of course, the foam envelope covering the shell is then more suitable to be machined on all its surface. Indeed, one of the faces being already laminated at the time of assembly, the geometry of this face can no longer be deeply modified. However, it has been found that, in order to significantly modify the final behavior of the gliding float, it is often enough to modify the geometry of the side edges of the float (usually called the float rails). Now this geometry can be modified even if one of the external faces of the float (for example the underside) is already stratified.

In the example illustrated in FIGS. 10 to 13, it can be seen that the two half-shells are not symmetrical. Indeed, it can be seen that the lower half-shell 24 does not comprise no side edges. When formatting, the plate is curved in the direction longitudinal (which is not visible in the drawings) to follow the camber curve longitudinal (sometimes called "rocker" or "scoop" curve). It could also be curved in the transverse direction, for example to form a hull V or double concave, but in the example shown the lower half-shell has no curvature cross. In this case, since the deformation of the foam plate with respect to at its initial plan state is relatively small, the shaping of the plate can be done without thermoforming, simply by pressing the plate against the mold by depression at the moment of stratification. After curing the resin, the stiffness of the resin-coated fabric is sufficient to maintain the plate to the desired shape of the half-shell.

On the contrary, the upper half-shell 22 is thermoformed so as to be curved longitudinally, but also transversely to form recurved lateral edges 36 down. According to the invention the internal faces (that is to say the lower face 30 of the half-shell upper 22 and the upper face 32 of the lower half-shell 24) are laminated with one or more layers of fiber fabrics impregnated with thermosetting resin. As can be seen in FIG. 10, the lower face 34 of the lower half-shell 24 is it also stratified, before assembling the two half-shells.

As can be seen in FIG. 11, the assembly of the two half-shells is obtained by gluing the lower edge of the lateral flanges 36 of the upper half-shell 22 against the face upper 32 of the lower half-shell 24. The glue will be chosen so as not to be too difficult to machine, that is to say, so as not to create a hard point in the foam constituent of the lateral edge of the subassembly.

With this construction, we see in Figure 12 (which illustrates in more detail the side edge of the subassembly just after assembly) that most of the height of the edge side 38 of the structural assembly is formed by the lateral flanges 36 of the half-shell upper whose outer face 40 is made of foam. The bottom part of these edges side is formed by the side edge of the lower half-shell which has a framed foam thickness 28 (top and bottom) by two layers of impregnated fabrics 32, 34. As the fabric thicknesses 32, 34 are very small, they do not form obstacle to the shaping by machining of the lateral edges. Thus, in FIG. see that the geometry of the lateral edge 38 of the structural subset has been modified on any the height of the lateral edge 38, for example by planing and sanding.

However, alternatively (not shown), we can make sure that the part device of the upper face 32 of the lower half-shell 24 is devoid of stratification so that the lateral flanges 36 of the upper half-shell 22 are resting against the foam 28, in order to ensure a better continuity of the material forming the side edge 38 which then consists of foam.

The stratification of the outer surface, in this case the lower surface 34 of the lower half-shell, can be total (as shown). It can also concern only one part of the surface, for example the central part to preserve perfect machinability of the side edge 38.

With this construction, the precise assembly of the two half-shells is facilitated by the high rigidity of the lower half-shell, and the sub-assembly remains able to be machined on its entire upper surface and on its lateral edges, which leaves a great capacity for customization of the subset. Once customized, the structural subset is covered with an outer layer of resin-impregnated fibers. Depending on the case, we can choose to also cover the already laminated outer surface 34 of the subassembly with this outer layer, to increase the rigidity and strength of the float, or on the contrary choose from do not cover this already laminated surface 34, in order to limit the weight of the float.

Of course, in the case where one wishes to privilege the possibility of personalizing the float hull, one could predict that the half-shell laminated on both sides is the upper half-shell, the lower half-shell then being laminated only on its face 32. In both cases, the subset thus produced is a subset which, at meaning of the invention, includes a hollow and rigid inner shell, and a shell of foam capable of being machined which completely covers this inner shell. optionally a part of this envelope (which we do not want to change the geometry, for example the upper face of the upper half-shell or the lower face of the lower half-shell), can be covered with a rigid outer layer.

As in the case of the embodiments of FIGS. 7 and 9, it will be possible advantageously provide to provide the subset of Figures 10 to 13 of a partition longitudinal central vertically connecting the two half-shells.

Naturally, this description is only indicative, and one could adopt other implementations of it without departing from the scope of this invention. For example we could double the inner shell and thus perform a stacking alternately comprising fiber webs and foam layers for the subassembly. We could still have several longitudinal, transverse or other partitions appropriate directions, these partitions forming links between the bridge and the hull of the float. Eventually, these partitions can create a partitioning of the inner shell in several watertight compartments.

In addition, the invention could be applied for the construction of floats other than surf floats, for example for windsurfing floats, floats intended for swimming in the waves and overall, any nautical practice in which the float Mostly works in the preview mode.

Claims (12)

1. Structural subassembly provided to produce an aquatic gliding board, the subassembly having a shape close to the final shape of the board, characterized in that it includes a hollow inner shell (7, 10, 15, 20) which is covered with a casing (8, 12, 18, 21) made of foam capable of being shaped, the foam defining at least in part the external surface of the assembly.
2. Subassembly according to claim 1, characterized in that the inner shell (7, 10, 15, 20) is made of resin-impregnated fibers.
3. Subassembly according to claim 1, characterized in that the inner shell (7, 20) is reinforced by a central partition (14, 17).
4. Subassembly according to claim 1, characterized in that the upper wall of the inner shell (15, 20) is supported by a curved plate (16, 18) located within the shell.
5. Subassembly according to claim 2, characterized in that the wall of the shell is 0.1-2 millimeters thick.
6. Subassembly according to claim 1, characterized in that the casing is made of polystyrene foam.
7. Subassembly according to claim 1, characterized in that the casing is made of polyurethane foam.
8. Subassembly according to claim 1, characterized in that the casing is made of PVC foam.
9. Subassembly according to claim 1, characterized in that the foam casing is locally reinforced by a honeycombed structure.
10. Subassembly according to claim 1, characterized in that the thickness of the foam casing is comprised between 3 and 20 millimeters.
11. Method of manufacturing a structural subassembly provided to produce an aquatic gliding board, characterized in that it comprises the following steps:

    forming an upper half-shell comprising a foam layer capable of being shaped, covered on its lower surface with an inner layer of thermosetting resin-impregnated fibers;

    forming a lower half-shell comprising a foam layer capable of being shaped, covered on its upper surface with an inner layer of thermosetting resin-impregnated fibers;

    assembling the two half-shells so that said inner layers of thermosetting resin-impregnated fibers form a hollow shell covered with a casing made of foam capable of being shaped.
12. Method according to claim 11, characterized in that, before the assembly of the half-shells, the method comprises the supplemental step of covering a portion of at least one of the half-shells with an outer layer of thermosetting resin-impregnated fibers, nevertheless leaving a part of the foam casing free of outer layer.

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