AU2005242175A1 - Board for gliding on water having a braced core - Google Patents

Description

S&F Ref: 744624

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: Salomon of Lieudit La Ravoire, F-74370, Metz- Tessy, France Francois Guers Jerome Ricart Spruson Ferguson St Martins Tower Level 31 Market Street Sydney NSW 2000 (CCN 3710000177) Board for gliding on water having a braced core The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5845c BOARD FOR GLIDING ON WATER HAVING A BRACED CORE The invention relates to the field of boards for gliding on water such as a surf 00 board or sail board.

Traditionally, a surf board is produced from a foam slab, particularly polyurethane foam, which is formed in a mould. The foam slab is machined by planing and sanding to a fine thickness to give an individual touch in places to its shape and to form the core of the board. The core is then covered with a resin-impregnated glass fibre envelope which forms a reinforcing outer shell and gives the board its final shape.

Decoration and glazing provide the board with its final appearance.

In certain cases, the core is cut longitudinally into two parts which are then bonded on to a wooden lath which reinforces its structure and imposes on it a predetermined longitudinal camber.

The drawback of such a construction technique is the final weight of the board.

This is because the foam is relatively dense, typically its density is 50 kg/in 3 And it is not possible a priori to decrease the density of the foam without impairing the mechanical properties of the board.

According to another method of construction deriving from the sail board, construction starts with a slab of foam of relatively low density (for example 18 kg/in 3 which is machined so as to give it its shape, or which is moulded directly in the shape of the core of the board. The core is covered with an external envelope, which can be comprised of resin-impregnated glass fibre skin, and/or a thermoformed plastic sheet, and/or a skin of sandwich construction. Such a method of construction can allow a saving in weight while maintaining appropriate stiffniess underfoot, particularly when a sandwich construction is used. However its implementation is relatively complex.

Finally, production of hollow boards with sandwich skins is known. For example, two half-shells can be produced which are then assembled together, or the whole can even be' produced in a closed mould with an internal bladder which is inflated to press and apply the sandwich skins against the walls of the mould.

The hollow slabs from which the envelope is produced in the form of a sandwich construction have a priori the best balance between weight and longitudinal flexural stiffness of the board. However, fabrication of a predominantly hollow board is delicate and such boards occasionally have some brittleness.

The aim of the invention is to propose a novel construction for a board for gliding on water which allows a board to be produced which is not only light and stiff in IR:\LIBLLJ 17909.doc: L2V longitudinal bending, but which also provides the board with good shock resistance and above all a performance in the water which is both lively and accommodating.

SFor this purpose the invention proposes a board for gliding on water of the type 00 comprising a core covered by an outer envelope forming a deck and hull, characterised in that the core consists of a main part formed from a first honeycomb material, and at least one brace which connects the deck to the hull, the said brace consisting of a second _honeycomb material which has a mechanical resistance to compression greater than that N of the first honeycomb material, and the said brace being elastically compressible in the N deck-hull vertical direction.

tn Other characteristics and advantages of the invention will become apparent by N reading the detailed description which follows, as well as viewing the annexed drawings in which: Figure 1 is a schematic top view of a board conforming to the instructions of the invention; Figure 2 is a schematic top view of the core of the board in Figure 1; Figures 3 to 5 are schematic cross-section views respectively through the lines III-III, IV-IV, V-V of Figure 1; and Figures 6 and 7 are schematic cross-section views illustrating two methods of producing a board equipped with a core conforming to the instructions of the invention.

Figure 1 illustrates the general outer form of a board for gliding on water 10, for example a surf board, and, in dotted lines, the arrangement of a core 14 inside an outer envelope 12 of the board. This core 14 is illustrated on its own in Figure 2. In a wellknown way, the outer envelope forms, in its upper part, the deck of the board on which the user is intended to rest, and in its lower part, the hull which is lying in the water. The peripheral lateral edge of the outer envelope defines the track of the board. Of course, this outer envelope defines, in water-tightness terms, an internal space of the board which is entirely or partially (as in the illustrated example) filled by the core 14.

The illustrated core 14 consists of a main part 16 which here is made in the form of four components: two central components 16a and two side components 16b. The core also includes at least one brace, in this case three braces 18, a central brace 18a and two side braces 18b. As can be seen in Figures 3 to 5, the braces are designed to extend over the full height of the internal space of the board so as to connect the deck to the hull. As will be detailed further on, the shape, number and arrangement of the braces are able to be adapted in each case depending on the desired type of board, the activity undertaken, the [R:\LIBLL] I 7909.doc:LZV conditions experienced and the user for which it is intended (in particular their weight and Nlevel of practising the activity).

a) One of the aspect of the invention is that the brace is connected both to the deck 00oO and the hull, at least under the forces/stresses to which the board is usually subjected during use. In any case, contact of the brace with the deck and/or hull can be a continuous or discontinuous contact, extending or not over the entire area of the surfaces opposite the brace and the outer envelope. Similarly, particularly if the contact is discontinuous, Sprovision can be made that the contact zones of the brace with the hull are arranged more N or less in the vertical projection of the contact zones of the said brace with the deck, or conversely the respective contact zones are partly or completely offset.

SAccording to another aspect of the invention, the brace 18 can be compressed vertically in the deck-hull direction. Actually, in the prior art, the laying out of stiffening components arranged in longitudinal or transverse directions, is comprehensively kniown in boards for gliding on water. According to the most traditional construction technique, and the most widely used in the field of surf boards, the foam core is divided in its middle by a wooden lath (often called "stringer") which generally occupies the entire height of the board and which is thus in contact with the deck and the hull of the board. Now this wooden lath is especially stiff in compression.

In contrast, the brace(s) according to the invention are designed to allow a variation in the vertical distance separating the deck and hull under the effect of loads and stresses imposed firstly by the user on the deck, and secondly by water on the hull. This is because it is apparent that the performance of the board is improved by such a decoupling between the deck and hull.

Now, the decoupling is possible only if the deck and hull are free of any linkage in the vertical direction, as in the case of completely hollow boards, or connected by compressible components.

Thus the brace(s) will be produced so as to provide both a spring action and a damping action on the relative motions of the deck and the hull in the vertical direction.

In the illustrated example, the braces are made in the form of plain blocks of honeycomb material, more precisely in the form of plastic foam blocks.

Trials have shown that not all materials would be suitable. Most obviously, the wood, thermosetting resins or rigid thermoplastic resins which were proposed in the past for making "stringers" turn out to be unsuitable for forming the braces according to the invention. Likewise, all plastic foams can not be suitable.

[R:\LIBLL] 17909.doc:LZV Actually the specialist is in the habit of classifying plastic foams into flexible foams on the one hand, and into rigid foams on the other hand. The rigid foams have low Sflexibility in the sense that'as soon as the compressive force exceeds a certain value, they 00 are deformed by collapsing irreversibly or not very reversibly. Among the rigid foams, the polyurethane foams and extruded polystyrene foams can be cited which are generally used in the form of foam slabs to make the cores of traditional surf boards. Similarly, some PVC foams or polyamide foams generally used as a core in sandwich construction IC are unsuitable for producing the braces according to the invention.

IC Among the usable materials, the plastic flexible foams with an elastic property preferably will be chosen. Tests have shown that the expanded polyolefine foams, notably N, polypropylene foams, or even polyethylene foams, were particularly appropriate.

In the case of expanded polypropylene foams, grades having apparent densities between 25 and 100 kg/m 3 for example can be used. These materials generally have a stress at 25% of compression deformation of the order of 100 to 600 kPa.

The main elements of choice of the material will be its resistance to compression, but even more its elastic deformation capability (the material will have to preferably regain its initial shape after a compression of the order of and its capacity to return the energy absorbed during the compression.

When, as is illustrated in the figures, the core 14 includes several braces 18a, 18b, the braces themselves can be produced in different materials, particularly according to their position in the board. However, each of the materials forming the various braces will have to respond to the conditions of the specifications defined above.

The choice of producing the braces in the form of plain blocks of foam permits the desired properties to be obtained particularly easily and economically, while providing low weight to these components. Nevertheless, other modes of production can be envisaged. Thus provision can be made to use blocs consisting of superimposed different honeycomb materials having different characteristics, in order to refine the "response curve" of the brace to the compression loads. A more or less incompressible material also can be selected to be interposed between the block of honeycomb material(s) and the deck and/or hull (for example to reduce the maximum relative displacement of the deck with regard to the hull).

In any case, the connection between the deck and the hull provided by the brace(s) must allow elastic displacement of one relative to the other, at the very least for stress values corresponding to the usual values encountered during use of the board. But [R:\LIBLL] 1 7909.doc:LZV the invention also provides that the braces are not the only components of the core inside the board.

SIn fact, it is obviously technically advantageous that the braces are 00 supplemented, inside the board, by other core components such as those illustrated in the figures.

These components, which form the main part of the core, are made from honeycomb material with the main aim of filling at least part of the internal space of the board with the lightest possible material. Actually, the main part of the core is relieved of a good part of the loads by means of the braces, and it becomes possible to select the material on criteria other than simple mechanical strength. Consequently the honeycomb CI material forming the main part will have mechanical properties inferior to that of the honeycomb material which is in the brace(s). Preferably the material will have sufficient elasticity to not disrupt the function of the braces, such has just been described.

Preferably a closed-cell foam will be decided on for the main part of the core.

is That will have the advantage of limiting the amount of water likely to be taken on board the board in the case of deterioration of the outer envelope.

To produce the main part of the core, the use can be envisaged of very low density, expanded polystyrene foam, for example with an apparent density less than kg/m 3 or even equal to or less than 18 kg/m 3 However, other materials also can be envisaged, notably materials having a more pronounced elastic property such as the polyolefine foams described previously. Thus polyethylene foams, or even very low density polypropylene foams, for example of the order of 20 kg/m 3 can be used advantageously. In this latter case, the core could, for example, be constructed with a material of the same kind, but in different densities depending on whether it is a matter of the main part of the core or the braces.

As for the braces, it is possible to choose to produce the various components 16a, 16b of the main part 16 of the core 14 with different materials, each one however having to match the above properties.

Furthermore, the core can also include localised reinforcements of especially strong material, provided that the reinforcements do not stretch over the total height of the internal space delimited by the envelope, due to the risk of nullifying the advantage of the presence of the compressible braces. However, if it is a question of a reinforcement constructed close to the peripheral edge of the board (on the sides or fr-ont or rear ends), as for example a reinforcement for accommodating a fin housing, then it can extend over the total height of the internal space, without preventing, at the centre of the board or [R:\LIBLL] 17909.doc:LZV beneath certain support areas, the deck remaining at least partially decoupled from the hull.

SIn the illustrated example, the braces are produced in the form of longitudinal 00 partitions which extend parallel to one another over almost the entire length of the internal space of the board, approximately in the longitudinal direction of the board. The partitions have a width of some centimetres, for example about 1 to 4 centimetres.

However, even other configurations are possible. Thus provision can be made that the C braces are arranged in the form of partitions of various widths and/or orientations, I possibly shorter, or even forming a regular or irregular grid. Provision could be made for the braces to be arranged in the form of blocks extending over one or more zones N, corresponding to the main support areas of the user on the deck of the board.

In the illustrated example, the core does not entirely fill the internal space of the board, so that it allows the hollow internal zones 20 to remain inside the outer envelope.

Here these hollow zones are provided at the front of the board, a zone generally on which the user hardly rests. The presence of hollow zones obviously has a favourable effect on the weight of the board and their distribution will influence the dynamic moment of inertia of the board, which will have an effect on its behaviour in the water, particularly its response to the various pressures and changes in direction imposed by the user.

In this case, the central components 16a of the main part of the core only stretch the rear two thirds of the board, leaving the hollow zones in the front of the board.

Conversely the lateral components 16b extend over the whole length of the board (it is a question obviously of the available length in the corresponding zone of the board).

In Figures 3 to 5, it can be seen that the various components of the main part of the core are, like the braces 18, in contact at the same time with the deck and hull. In that way, a core having a more or less continuous outer surface is obtained, which facilitates the bond with the outer envelope. However in some cases provision could be made that there be a slight vertical separation between one or more of the components 16a, 16b of the main part of the core 14, and the hull or the deck. Such a separation could enable checking that the near-entirety of the vertical compressive forces absorbed by the core are absorbed by the braces, whose mechanical behaviour can be easily controlled precisely.

Furthermore, it can be seen in the figures that some of the components of the core have drilled lightening holes 22. In this case, the lightening holes 22 are cylindrical openings of some centimetres in diameter which go vertically right through the central components of the main part 16 of the core. The lightening holes could have other configurations, like for example having a different shape, being blind holes, etc Their [R:ALIBLL] 17909.doc:I.ZV number and position can be varied, and, in the case of braces with larger dimensions than those illustrated, provision can be made that they are put into the brace(s), in order to Sdecrease weight. Similar processes for lightening the core, such as those described in the 00 documents FR-2.820.712, FR-2.820.713 and FR-2.820.714, can be implemented advantageously within the scope of this invention.

Several processes can be envisaged to undertake the production of a board according to the invention.

i For the production of the core, it is possible to consider creating each of the core I components, both the component(s) of the main core and the braces, and to assemble all O 10 these components together, for example by bonding, to form a unitary whole.

Ni By way of variation, provision can be made for example that the braces are shaped beforehand, by machining or moulding directly into the shape, and that they are introduced into a mould to be moulded onto by the material constituting the main part of the core, the said mould giving the main part of the core either its final shape, or a similar i 5 shape capable of being retouched. In that case, the moulding-on can permit the assembly of the various components of the core to be undertaken, or it may be necessary to make provision for additional operations to put together the different components.

In both cases a complete core is obtained, around which the outer envelope can be constructed. The outer envelope 12 can, as illustrated in Figure 6, be produced in the form of two half-shells 12a, 12b, forming respectively the deck and hull, the half-shells being assembled together, for example by bonding along their joining plane, to form a water-tight, outer envelope.

In the example in Figure 6, the two half-shells 12a, 12b have a sandwich construction in which a sheet of light material (rigid foam, honeycomb, etc forming the core 24 of the sandwich, is confined between two layers (inner layer 26 and outer layer 28) of reinforcing material which form the skins of the sandwich and which consist of layers of fibres embedded in a resin for example.

The example in Figure 7 illustrates a variation in implementing the process of Figure 6 in which the two half-shells 12a, 12b are assembled together before the outer skin is put on to the layer forming the core 24 of the sandwich. Such a process is similar to that described in the document WO-02/10011, reference to which will be useful, and has the advantage of allowing the opportunity of starting work on the layer forming the core 24 of the sandwich, after assembling the two half-shells 12a, 12b, but before fitting the outer layers 26 of the sandwich, so as to individualise the shape of the board, if that is desirable.

[R:LIBLL 17909.doc:LIZV In the two cases illustrated, the outer envelope has a sandwich construction N which provides it with a characteristic strength, which nevertheless allows it to benefit from the compressible nature of the braces according to the invention. Actually, although 00 rigid, the sandwich structures are able to deform, at least locally, under the loads induced by use of the board. The use of an envelope having at least in part a sandwich construction will be especially suitable when the core is only a partial core leaving hollow zones inside the sandwich. In fact, the intrinsic strength of the sandwich, particularly its high resistance in bending, will avoid the hollow zones creating areas of very high NI brittleness in the board.

However, the core according to the invention can also be covered by an outer N1 envelope in accordance with the various well-known techniques of the specialist expert in the construction of boards for gliding on water. These techniques can end up in the envelope not having a sandwich construction but having a simple composite structure comprising for example fibres embedded in a resin, or even a simple layer of plastic material, for example obtained by thermoforming. The more simple envelopes can be suitable particularly for the production of boards in which the core will be more or less full, that is to say filling more or less all the internal space delimited by the outer envelope, and/or for boards for which the aspects of bending stiffness are not essential.

(R:\LIBLL] 17909.doc:LZV

Claims (15)

1. A board for gliding on water, of the type comprising a core covered by 00an outer envelope forming a deck and hull, wherein the core consists of a main part formed from a first honeycomb material, and at least one brace which connects the deck to the hull, the said brace consisting of a second honeycomb material, and the said brace being elastically compressible along the deck-hull vertical direction.

2. A board for gliding on water according to Claim 1, wherein the second to honeycomb material has an apparent density greater than that of the first material.

3. A board for gliding on water according to either of Claims 1 and 2, wherein the second honeycomb material has a mechanical resistance to compression greater than that of the first honeycomb material.

4. A board for gliding on water according to any one of the preceding claims, wherein the second honeycomb material is a flexible material. A board for gliding on water according to any one of the preceding claims, wherein the second honeycomb material is a polyolefine foam.

6. A board for gliding on water according to Claim 5, wherein the second honeycomb material is a polypropylene foam.

7. A board for gliding on water according to any one of the preceding claims, wherein the second honeycomb material has an apparent density between 25 and 100 kg/m 3

8. A board for gliding on water according to Claim 7, wherein the first honeycomb material has an apparent density less than 25 kg/m 3

9. A board for gliding on water according to any one of the preceding claims, wherein the first honeycomb material consists of an expanded polystyrene foam. [R:\LIBLLII 7909.doc: LZV A board for gliding on water according to any one of the preceding N claims, wherein the brace(s) are preferentially arranged in the areas of the board Scorresponding to support areas of the user on the deck of the board. 00

11. A board for gliding on water according to any one of the preceding claims, wherein the brace(s) appear in the form of one or more partitions connecting the deck to the hull. N 12. A board for gliding on water according to Claim 11, wherein 'the 1o brace(s) comprise at least one longitudinal partition.

13. A board for gliding on water according to any one of the preceding claims, wherein the main part of the core is formed of several components.

14. A board for gliding on water according to any one of the preceding claims, wherein the core includes lightening holes. A board for gliding on water according to any one of the preceding claims, wherein the core is a partial core so that the outer envelope of the board delimits hollow internal zones.

16. A board for gliding on water according to any one of the preceding claims, wherein the core is formed of several elements assembled together.

17. A board for gliding on water according to Claim 16, wherein the components of the core are at least partly assembled by bonding.

18. A board for gliding on water according to Claim 16, wherein the components of the core are at least partly assembled by moulding-on.

19. A board for gliding on water according to any one of the preceding claims, wherein the outer envelope is made of composite materials. [R:\LI BLLJ 17909.doc: LZV A board for gliding on water according to Claim 19, wherein the outer o envelope comprises at least one part produced in the form of a sandwich construction of composite materials. 00 s 21. A board for gliding on water, said board being substantially as hereinbefore described with reference to Figs 1 to 5 and either Fig 6 or Fig 7 of the accompanying drawings. Dated 7 December, 2005 00 Salomon S.A. Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON [R:\LIBLL] 7909.doc:LZV