WO2006061511A1

WO2006061511A1 - Surf board floater with hybrid spacers

Info

Publication number: WO2006061511A1
Application number: PCT/FR2005/003058
Authority: WO
Inventors: Jérôme RICART
Original assignee: Salomon S.A.
Priority date: 2004-12-08
Filing date: 2005-12-06
Publication date: 2006-06-15
Also published as: FR2878818A1; FR2878818B1

Abstract

The invention concerns a surf board, of the type comprising an inner structure covered with an outer envelope (12) forming a deck and a bottom, said inner structure comprising at least one spacer (18) which connects the deck to the bottom. The invention is characterized in that said spacer (18) consists of at least two different parts which, in at least one hybrid zone of the spacer, are superimposed along the vertical deck-bottom direction, and in that at least one first of said at least two different parts is compressible and elastic such that the spacer is elastically compressible along the vertical deck-bottom direction.

Description

FLOAT FLOAT ON WATER WITH HYBRID SPACERS

The invention relates to the field of water gliding floats such as a surfboard float or windsurfing. The invention relates more particularly to hollow floats.

In a traditional way, a surf float is made from a foam roll, in particular polyurethane foam, which is formed in a mold. The foam roll is machined by planing and sanding to a small thickness to locally customize its shape and form the core of the float. This core is then coated with a resin-impregnated glass fiber shell which forms an outer reinforcing shell and gives the float its final shape. A decoration and an icing give the float its final appearance.

In some cases, the core is cut longitudinally into two parts which are then glued against a wooden lath which reinforces its structure and imposes a predetermined longitudinal camber.

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

According to another technique of construction resulting from the windsurfing, one starts from a foam roll of relatively low density (for example 18 kg / m3) which one manufactures so as to shape it, or that the mold directly to the shape of the float core. This core is covered with an outer shell, which may comprise a resin impregnated glass fiber skin, and / or a sheet of thermoformed plastic material, and / or a sandwich structure skin. Such a construction method can allow weight gain while maintaining good rigidity underfoot, especially when using a sandwich structure envelope. However, its implementation is relatively complex.

Finally, it is known to make hollow floats with sandwich skins. One can for example make two half-shells which are then assembled together, or even achieve all in a closed mold with an internal bladder that is inflated to push and apply the sandwich skins against the walls of the mold.

The hollow planks whose envelope is made in the form of a sandwich structure have a priori the best ratio between the weight and the rigidity in longitudinal flexion of the float. In WO-02/10011, there are described several embodiments of such a hollow sandwich float.

The object of the invention is to propose a new construction for a hollow glide float which not only makes it possible to obtain a light and rigid float in longitudinal flexion, but which also ensures the float behavior on the water at once lively and tolerant.

For this purpose, the invention provides a float glide on water, of the type comprising an internal structure covered by an outer shell forming a bridge and a hull, said internal structure having at least one spacer which connects the bridge to the hull , characterized in that said spacer is composed of at least two different parts which, in at least one hybrid zone of the spacer, are superimposed in the vertical hull-hull direction, and in that at least one of said at least two different parts is compressible and elastic so that the spacer is elastically compressible in the vertical direction keel-hull.

Other features and advantages of the invention will appear on reading the following detailed description, as well as on the attached drawings in which: FIG. 1 is a schematic view from above of a float in accordance with the teachings of the invention; FIG. 2 is a diagrammatic cross-sectional view from above of the core of the float of FIG. 1; Figure 3 is a schematic longitudinal sectional view of the float of Figure 1; Figures 4 to 8 are schematic views in longitudinal section illustrating several embodiments of a spacer according to the teachings of the invention; Figures 9 and 10 are schematic cross-sectional views illustrating two methods of producing a float with a core according to the teachings of the invention; Figure 11 is a partial cutaway view of a float comprising a spacer according to an alternative embodiment of the invention.

In FIG. 1, the external general shape of a gliding float on the water 10, for example a surf float, and in broken lines, the arrangement inside an outer envelope 12 is illustrated. float, internal structure 14.

In known manner, the outer casing 12, in its upper part, the bridge 12a of the float on which the user is intended to bear, and in its lower part, the hull 12b which bears on the water . The peripheral lateral edge of the outer envelope defines the rails 15 of the float. Of course, the outer casing 12 defines, in a sealed manner, a hollow internal space 17 of the float 10 in which the internal structure is arranged.

14. In order for the float 10 to be considered hollow, the internal structure 14 must occupy only a part of the volume of the internal space 17, for example less than 60% of this volume.

In the first embodiment of the invention illustrated in Figures 1 to 3, the internal structure is formed of spacers 18, in this case three spacers 18, including a central 18a and two side 18b. The spacers 18 are provided to extend over the entire height of the internal space 17 of the float 10 so as to vertically connect the bridge 12a to the hull 12b. In the illustrated examples, the spacers are made in the form of longitudinal retaining walls which extend parallel to one another over almost the entire length of the internal space of the float, substantially in the longitudinal direction of the latter. . Partitions have a width of a few centimeters, for example about 1 to 4 centimeters. However, many other configurations are possible. Thus, it could be provided that the spacers are arranged in the form of partitions of width and / or various orientations, possibly shorter, or forming a regular grid or not. It could be provided that the spacers are arranged in the form of blocks extending over one or more areas corresponding to the main bearing areas of the user on the deck of the float. In fact, the shape, number and arrangement of the spacers can be adapted case by case depending on the type of float desired, depending on the sport practiced, the conditions of the practice, and depending on the user to whom it is intended (especially its weight and level of sport practice). In the example illustrated, the internal structure occupies only a small part of the volume of the space, in this case less than 40%, or even less than 25% of this volume.

However, the internal structure may also include localized reinforcements particularly resistant material, provided that they do not extend over the entire height of the internal space delimited by the envelope, otherwise cancel the benefit of the presence of compressible struts. However, if it is a reinforcement arranged near the peripheral edge of the float (on the sides or at the front or rear ends), such as a reinforcement for housing a flap case, then it can extend over the entire height of the internal space, without preventing that, in the center float or under certain support zones, the bridge remains at least partially decoupled from the hull.

One aspect of the invention is that the spacer is bonded to both the deck and the hull, at least under the stresses / stresses that the float is usually subjected to during its use. In all cases, the contact of the spacer with the bridge and / or the hull may be a continuous or discontinuous contact, extending or not over the entire surface area of the faces facing the spacer and the outer envelope . Similarly, especially if this contact is discontinuous, it can be provided that the contact zones of the spacer with the hull are arranged substantially in the vertical projection of the contact zones of said spacer with the bridge, or that, on the contrary, the respective contact areas are partly or entirely offset.

According to another aspect of the invention, the spacer 18 is compressible vertically in the deck-hull direction. Indeed, it is widely known from the prior art to have, in the gliding floats, stiffening elements arranged in longitudinal or transverse directions. According to the most traditional construction technique, and the most common in the field of surfboards, the foam core is separated in the middle by a wooden slat (often called "stringer") which usually occupies the full height of the board and which is in contact with the deck and with the hull of the float. This wooden batten is particularly rigid in compression.

On the contrary, the spacer or spacers according to the invention are provided to allow a significant variation in the vertical distance separating the bridge from the hull under the effect of the forces and constraints imposed on the one hand by the user on the bridge, and on the other hand by Water on the hull. Indeed, it appeared that the behavior of the float was improved by such a decoupling between the bridge and the hull.

Or ₅ this decoupling is only possible if the deck and hull are free from any rigid connection in the vertical direction, as in the case of completely hollow boards or linked by compressible elements.

Thus, the spacers or spacers will be made to provide both a spring effect and damping effect relative movements of the bridge and the hull in the vertical direction. Furthermore, the fact that these spacers occupy a small volume also allows to ensure good freedom of relative deformation between the bridge and the hull, which allows to obtain the desired decoupling. Full or substantially solid floats in which at least a substantial part of the float is occupied by foam (generally rigid foam such as polyurethane foam, polystyrene foam (in particular extruded), foam of PVC, etc.), do not allow satisfactory decoupling of the deck relative to the hull. According to one aspect of the invention, at least one of the spacer is composed of at least two different superposed parts, at least one of these parts being compressible and elastic.

Thus, in the first exemplary embodiment of the invention which is illustrated in FIG. 3, it can be seen that spacer 18 (18a, 18b) consists of two superimposed materials, each material forming one of the parts. A first material C is arranged in contact with the float bridge and a second material R is arranged in contact with the hull. In this first example, we see that the two materials are superimposed over the entire length (but also over the entire width) Fentretoise. This has a height (in the vertical hull-to-hull direction) that varies along its length, depending, of course, on the available height of the internal space of the float delimited by the outer envelope 12. Here, the two materials represent in all respects, substantially half the height of the spacer.

As a variant, it could be provided that the layer of compressible material C has a smaller thickness than that of the other material R. It would be for example constant over the entire length of the spacer, and for example of the order of 2 to 5 mm, or about 10% of the maximum height of the fentretoise (see Figure 9). In the example illustrated, the first material C, which constitutes the upper layer of

Fentretoise, which is in contact with the bridge, is that of the two materials which is the elastic compressible material.

In the illustrated example, this first material C is a cellular material, more specifically a block of plastic foam. However, not all plastic foams will be suitable.

Indeed, the skilled person has a habit of classifying foams plastic flexible foams on the one hand and stiff foams on the other. Rigid foams have a low elasticity in that as soon as the compression force exceeds a certain value, they deform by collapse, irreversibly or very little reversible. From rigid foams include some polyurethane foams and extruded polystyrene foam which are generally used in the form of foam buns to form the kernels of traditional surfboards. Similarly, some foams of PVC or polyimide generally used as a core in the sandwich structure are unsuitable for constituting the first spacer material according to the invention.

Among the materials that can be used, resilient foams of resilient plastics material will preferably be selected. Tests have shown that foams of expanded polyolefins, in particular polypropylene or even polyethylene, are particularly suitable. x? In the case of expanded polypropylene foams, it is possible, for example, to use grades having apparent densities of between 20 and 100 kg / m 3. These materials generally have a stress at 25% of compressive strain of the order of 100 to 60O kPa. ^{* '' • '}

The principal elements of choice of the material will be its stiffness to the compression, but still more its capacity of elastic deformation (the material will preferably have to recover its initial form after a compression of the order of 25%), and its capacity of restitution of the energy absorbed during compression.

For the constitution of the second part of the spacer, the choice is wider.

We can first choose to make the spacer in a rigid material R, such as the rigid foams mentioned above, honeycomb materials, wood, etc ...

It is also possible to use a compressible material R, which is therefore flexible, but exhibits mechanical characteristics different from those of the first material, particularly with respect to the characteristics of compression behavior. It will thus be possible to choose a stiffer material, and / or a more or less damping material, etc. Optionally, the second material will be, like the first, a plastic foam, and therefore a cellular material, or even a plastic material. same chemical composition but having for example a higher apparent density.

In the example chosen, it is preferred that the compressible material in the sense of the invention is that in contact with the bridge, the material in contact with the hull being chosen preferably more rigid. In this way, a greater stiffness of the hull (favorable to the speed and vivacity of the float) and greater flexibility of the deck (favoring control and tolerance) are favored.

However, for some applications, the opposite may be possible.

An example of a combination of materials is to use a compressible expanded polypropylene foam over extruded polystyrene foam which, by comparison, will be stiffer.

Furthermore, it is also possible to implement the invention with a spacer having three layers of superimposed materials. In this case, it is possible for example to provide that a layer of the first elastic and compressible material is interposed between two layers of a same stiffer material. It can also be expected that the three superimposed layers are formed of different materials. In all cases, it will be ensured that, in at least one selected zone of Fentretoise, there are at least two superposed parts, one of these parts being compressible and elastic. In the example illustrated in Figures 2 and 3, the spacers comprise two parts superimposed over their entire width and over their entire length.

However, the invention may also be implemented in spacers where the superposition according to the invention will be found only in certain areas of the spacers, called hybrid zones. There are several ways to achieve each of the parts, including the second part.

In the example illustrated in Figures 1 to 3, each of the parts consists of a single material, so that the two superimposed parts are summarized in two materials. However, other embodiments are possible.

Thus, in Figure 11, there is illustrated an embodiment of a spacer (cross-sectional view), wherein the spacer 18 comprises a main body 19 which is made of a compressible and elastic material, compatible with the requirement of compressibility and elasticity of the invention. This main body 19 is designed to extend vertically from the deck to the hull, over the entire height of the internal space 17. However, over part of its height, this main body 19 is doubled, on at least one of its lateral faces (in this case on both lateral faces), by at least one lateral veneer 21. These lateral veneers 21 may be made of rigid material, such as fibers impregnated with resin, wood, honeycomb material, rigid foam etc. They can also be made of a compressible and elastic material having mechanical characteristics different from those of the material constituting the main body. In both cases, it can be provided that the veneers 21 are glued on the side faces of the main body 19, or that the veneers are just juxtaposed or even juxtaposed with a space. In the case of gluing, the veneers will block the corresponding part (in this case the lower part) of the main body and prevent it from compressing, or at least limit its compression to a level determined by the veneers. If the veneers 21 are rigid, the lower part of the main body will not compress. If the veneers are soft, the lower part of the main body will follow the movements of the veneers. However, the latter will be effectively solicited in compression only beyond a certain degree of compression of the part of the main body which is free of plating (in this case the upper part of P spacer), which remains obviously compressible and elastic. If the veneers are simply juxtaposed, the entire main body may be compressed, but, beyond a certain bridge and hull closer, the veneers can come into action to give the additional rigidity desired.

Of course, the shape of the veneers will be adapted (in particular in height or in width), according to various parameters such as the materials in the presence, etc ... With such a construction, the spacer has a composite part (in this case the lower part) in which several materials are juxtaposed laterally. The compressibility (or incompressibility) of this part then results from the combined mechanical properties of the juxtaposed materials. Of course, the compressible portion of the spacer could also have a composite construction of the same kind, provided to meet the constraints of compressibility and elasticity.

Regarding the possible arrangements for the hybrid zone or zones, the few non-limiting examples described in FIGS. 4 to 8 give an indication of various possible combinations within the scope of the invention. In Figure 4, the spacer 18 has a single hybrid zone Z, located in an area corresponding for example to a support zone of the feet of a user when using the float. The thickness of the layer of compressible material C is not uniform.

In FIG. 5, the spacer 18 has two distinct and separate hybrid zones Z1 and Z2, each formed of the same compressible material C or of two different compressible materials C1 and C2, as in the case illustrated in FIG. are otherwise adjacent.

In Figure 7, the spacer has a hybrid zone Z where two compressible materials C1 and C2 are superimposed over a layer of a third material. The two layers of compressible materials each have a substantially constant height. In FIG. 8, it can be seen that the spacer 18 comprises an insert of compressible material which, in a central zone, is intended to come into contact with both the bridge and of the hull. This insert has two connection areas with the second material constituting the remainder of the spacer, these connection areas being made according to inclined planes. As a result, the two connection zones being areas in which the two materials are superimposed, they form two hybrid zones Z1, Z2. In each of these two zones, the thickness of the compressible material layer ^is' progressive course. It is noted that the spacer has, between the two zones Z1 and Z2, an area consisting solely of the compressible and elastic material, which extends from the bridge to the hull.

When, as illustrated in FIGS. 1 to 3, the core 14 comprises several spacers 18a, 18b, the spacers may itself be made of different materials, and / or with different hybrid zones, in particular according to their position in the float. However, each of the materials constituting the different spacers must meet the conditions of the specifications defined above.

In all cases, the connection between the bridge and the hull provided by the spacer or spacers must allow an elastic displacement of one relative to the other, at least for stress values corresponding to the values usually encountered during the use of the float. For this, it is necessary that the internal structure 14 does not occupy all the internal space delimited by the outer envelope. The float according to the invention therefore remains a hollow float. The presence of hybrid zones will allow the designer of the gliding device to better control the decoupling between the deck and the hull. Indeed, it was found that it was interesting to have a very flexible bridge-hull connection in the first millimeters of relative approximation during the crushing effect of the bridge relative to the hull. Decoupling is then important: the hull remains little influenced by the forces imposed on the bridge. The bridge is then deformed to adapt to variations of support, while the hull keeps its optimum geometry.

However, it was found that the decoupling could become an obstacle to the vivacity and the control of the float during the more pronounced supports, corresponding to a more pronounced crash of the bridge with respect to the hull.

Thanks to the invention, the compressible part will absorb the first millimeters of deformation by compressing, but, beyond a certain threshold, its compressive strength increases. Below, the second part, if it is chosen stiffer, or even rigid, will stop or prevent a greater connection between the deck and the hull. Thus, the decoupling between the bridge and the hull is progressively managed, as a function of the intensity of the stresses imposed on the float, by obtaining two modes of operation: flexible or steeper, depending on the degree of depression.

The designer, by modifying the height ratios between the first and the second part, will be able to change the moment of transition between the two modes of operations, to obtain the desired behavior of the board. It has been seen that this modification of the height ratios was not only possible from one float to another, but also from one zone of one float to another zone of the same float.

Several methods can be envisaged to ensure the production of a float according to the invention. For the manufacture of the spacers, it is conceivable to separately create each of the elements of the spacer, and to assemble these elements together, for example by gluing, to form a unitary assembly.

The outer casing 12 may, as illustrated in FIG. 9, be in the form of two half-shells 12a, 12b forming respectively the bridge and the hull, the half-shells being assembled one to the other. other, for example by gluing along their joint plane, to form a sealed outer envelope.

In this example of FIG. 9, the two half-shells 12a, 12b have a sandwich construction in which a plate of light material (rigid foam, honeycomb, etc.), forming the core 24 of the sandwich, is imprisoned between two inner 26 and outer 28 layers of reinforcing material which form the skins of the sandwich and which comprise, for example, fiber sheets embedded in a resin. Preferably, the spacers are bonded, for example by gluing with the aid of any glue, to the two half-shells.

In the example of Figure 10, there is illustrated an alternative embodiment of the method of Figure 9 wherein the two half-shells 12a, 12b are assembled to each other before that the outer skin is applied to the layer forming the core 24 of the sandwich. Such a method is similar to that described in WO-02/10011, which will be usefully referred to, and has the advantage of allowing the opportunity to rework the core layer 24 of the sandwich, after assembly of the half-shells 12a, 12b, but before the laying of the outer layers 26 of the sandwich, this in order to customize the shape of the float, if this is desirable.

In both cases illustrated, the outer casing has a sandwich structure which ensures its own strength, which nevertheless allows to benefit from the compressible character of the spacers according to the invention. Indeed, although rigid, these sandwich structures will be deformed, at least locally, under the forces induced by the use of the float.

However, the internal structure according to the invention can also be covered with an outer envelope according to the various techniques known to those skilled in the art of the construction of hollow floats sliding on water.

Claims

1. Float gliding on water, of the type comprising an internal structure (14) covered by an outer casing (12) forming a bridge and a hull, said internal structure comprising at least one spacer (18, 18a, 18b) which connects the bridge to the hull, characterized in that said spacer (18) is composed of at least two different parts which, in at least one hybrid zone (Z, Z1, Z2) of the spacer, are superimposed in the direction vertical keel, and in that at least a first (C, Cl, C2) of said at least two different parts is compressible and elastic so that the spacer is elastically compressible in the vertical direction keel-hull.

2. Glide float according to claim 1, characterized in that the first part consists of a first cellular material (C, Cl, C2).

3. Glide float according to claim 2, characterized in that the first cellular material (C, Cl, C2) is a polyolefin foam.

4. Glide float according to claim 3, characterized in that the first foam material (C, Cl, C2) is a polypropylene foam.

5. Sliding float according to any one of claims 2 to 4, characterized in that the first material (C, Cl, C2) has an apparent density of between 25 and 100 kg / m3.

6. Glide float according to any one of the preceding claims, characterized in that the second part is flexible.

7. Glide float according to claim 6 taken in combination with claim 2, characterized in that the second part consists of a second material which is a cellular material having a bulk density greater than that of the first cellular material.

8. Gliding float according to claim 7, characterized in that the second cellular material has a higher compressive strength than the first cellular material.

9. Gliding float according to any one of claims 1 to 5, characterized in that the second part is rigid.

10. Sliding float according to claim 9, characterized in that the second part comprises a rigid foam.

11. Sliding float according to claim 10, characterized in that the second part comprises an extruded polystyrene foam.

12. Sliding float according to any one of the preceding claims, characterized in that the hybrid zone (s) (Z, Zl, Z2) or the spacers (18, 18a, 18b) are preferably arranged in areas of the float. corresponding to areas of support of a user on the float deck.

13. Floating slide according to any one of the preceding claims, characterized in that the spacer or spacers (18, 18a, 18b) are in the form of one or more partitions connecting the bridge to the hull.

14. Floating slide according to claim 3, characterized in that the spacer or spacers (18, 18a, 18b) comprise at least one longitudinal partition.

15. Floating slide according to any one of the preceding claims, characterized in that the outer casing (12) is made of composite materials.

Slide float according to claim 15, characterized in that the outer casing

(12) comprises at least one portion made in the form of a sandwich structure of composite materials.

17. Sliding float according to any one of the preceding claims, characterized in that at least one part of pentretoise (18) has a composite construction combining several materials.