A surfboard

Abstract

A surfboard having a core, a first elongate spring member located adjacent an upper side of the core, and a second elongate spring member located adjacent a 5 lower side of the core, wherein the first elongate spring member extends substantially from a nose portion of the surfboard to a tail portion of the surfboard. ABSTRACT2019 2019283772 16 Dec Fi gu re 1 1 / 6 22 14 16 10 24 12 34 20 19 28 37 72 1 6 D ec 2 01 9 14 10 1 16 22 1 / 6 24 34 12 Figure 1

Description

FIELD OF INVENTION The present invention relates to a surfboard. The present invention has particular but not exclusive application for a surfboard with energy recovery. The patent specification describes this use but it is by way of example only and the invention is not limited to this use. BACKGROUND OF THE INVENTION Surfboards are typically made of polyurethane or polystyrene foam covered with layers of fiberglass cloth, and polyester or epoxy resin. The use of these materials results in a light and strong surfboard that is buoyant and manoeuvrable. Fiberglass surfboards typically have a degree of flex. Flex allows a surfboard to build energy through turns by bending into a turn, this results in a greater vertical curve of the surfboard between the nose and the tail and stored energy. As the surfboard comes out of a turn, the surfboard snaps back to its original shape, releasing the stored energy and propelling the surfboard out of the turn. However, there is typically a trade-off between strength and flexibility, with more flexible surfboards typically more likely to snap or lose their springiness over time. Many surfboards have one or more stringers to increase the surfboard's overall strength. However, these stringers also reduce a surfboards flexibility. A single stringer down a board’s centre will provide strength but less flexibility along the centre of the board and can lead to torsional flex which can slow down a surfboard. Some boards have two stringers, each close to a rail of the surfboard. Surfboards with two stringers are typically stronger than surfboards with a single stringer, with the flex coming from the centre of the surfboard with two stringers. OBJECT OF THE INVENTION It is an object of the present invention to overcome or at least alleviate one or more of the above mentioned problems with surfboards and / or provide the consumer with a useful or commercial choice. 2019283772  16 Dec 2019 SUMMARY OF THE INVENTION In one aspect, the present invention broadly resides in a surfboard having a core; 5         a first elongate spring member located adjacent an upper side of the core; and a second elongate spring member located adjacent a lower side of the core; wherein the first elongate spring member extends substantially from a nose portion of the surfboard to a tail portion of the surfboard. 0          Preferably, the core is made predominantly from a foamed material. Preferably the core is a foam core. Preferably the foamed material is polyurethane foam. In another embodiment, the foam is polystyrene foam. Preferably the polystyrene foam is expanded polystyrene foam. Alternatively, the polystyrene foam can be extruded polystyrene foam. 5          Preferably the core includes a channel in a top surface thereof to accommodate the first elongate spring member. Preferably the channel in the upper surface is located centrally relative to a longitudinal axis of the surfboard. Preferably the core includes a channel in a lower surface thereof to accommodate the second elongate spring member. Preferably the channel in the lower surface is located 0 centrally relative to a longitudinal axis of the surfboard. Preferably the channel in the upper surface extends substantially from the nose portion of the surfboard to the tail portion of the surfboard. Preferably the channel in the lower surface extends substantially from the nose portion of the surfboard to the tail portion of the surfboard. Preferably the channel in the upper 25 surface has a depth of substantially between 1mm to 5mm. More preferably the channel in the upper surface has a depth of substantially between 1mm to 3mm. Preferably the channel in the lower surface has a depth of substantially between 1mm to 5mm. More preferably the channel in the lower surface has a depth of substantially between 1mm to 3mm. 30          Preferably the channel in the upper surface has a width of substantially between 30mm to 200mm. More preferably the channel in the upper surface has a width of substantially between 40mm to 80mm. Preferably the channel in the lower surface has a width of substantially between 30mm to 200mm. More preferably the channel in the lower surface has a width of substantially between 40mm to 80mm. 2019283772  16 Dec 2019 Preferably the channel in the upper surface tapers to a point at or towards the nose portion of the surfboard. Preferably the channel in the lower surface tapers to a point at or towards the nose portion of the surfboard. Preferably the channel in the lower surface tapers to a point towards the tail portion of the surfboard. In one embodiment, the channel in the upper surface tapers to a point at or towards the tail portion of the surfboard. Preferably the first elongate spring member is made of a resilient material. In one embodiment, the first elongate spring member is made of a fibreglass composite material. Preferably the first elongate spring member is made of a fibreglass and resin composite material. In another embodiment, the elongate spring member is made of a carbon fibre composite material. Preferably the elongate spring member is made of a carbon fibre and resin composite material. Preferably the first elongate spring member tapers from a thicker portion to a thinner portion towards the nose portion of the surfboard. Preferably the first elongate spring member tapers from a thicker portion to a thinner portion towards the tail portion of the surfboard. Preferably the first spring member has a width that is greater than the thickness of the first spring member. Preferably the width is in the direction of the rails of the surfboard. Preferably the first elongate spring member has a thickness of substantially between 1mm to 5mm. More preferably the first elongate spring member has a thickness of substantially between 1mm to 3mm. Preferably the first elongate spring member has a width of substantially between 15mm to 200mm. Preferably the first elongate spring member has a width of substantially between 15mm to 80mm. More preferably the first elongate spring member has a width of substantially between 20mm to 40mm. Preferably the first elongate spring member tapers to a point at or towards the nose portion of the surfboard. Preferably the first elongate spring member comprises a plurality of layers of resilient material. Preferably the number of layers of resilient material define the thickness of the first elongate spring member. Preferably the number of layers of resilient material is greater in a central portion of the first elongate spring member compare to the first elongate spring member towards the nose portion of the surfboard, and compared to the first elongate spring member towards the tail portion of the surfboard. Preferably the plurality of layers of resilient material is between 2 to 2019283772  16 Dec 2019 8 layers of resilient material. More preferably the plurality of layers of resilient material is between 4 to 6 layers of resilient material. Preferably in use, the inner layer(s) of resilient material towards the core are / is shorter than the outer layer(s) of resilient material. Preferably each layer of the plurality of layers of resilient material 5 has a different length. Preferably the plurality of layers are bonded together to form the first elongate spring member. More preferably the plurality of layers are bonded together using an epoxy to form the first elongate spring member. Preferably a thin portion of the first elongate spring member is less than 50% of the thickness compared to a thick portion of the first elongate spring member. Preferably the thin 0 portion includes 1 to 2 layers of resilient material. Preferably the thick portion includes 4 to 6 layers of resilient material. In one embodiment, the first elongate spring member is pretensioned. Preferably the first elongate spring member is pretensioned in a first direction. Preferably the first elongate spring member is biased to bend away from the core. 5 Alternatively the first elongate spring member is pretensioned in a second direction, biased to bend towards the core. Preferably the first elongate spring member is formed in the channel in the upper surface of the core. Alternatively the first elongate spring member is pressed into the core to create the channel in the upper surface of the core. 0          Preferably the second elongate spring member is made of a resilient material. Preferably the second elongate spring member is made of a fibre and resin composite material. Preferably the fibre is substantially unidirectional. Preferably the fibre is substantially unidirectional in the longitudinal direction of the surfboard. In one embodiment, the second elongate spring member is made of a fibreglass 25 composite material. Preferably the second elongate spring member is made of a fibreglass and resin composite material. In another embodiment, the second elongate spring member is made of a carbon fibre composite material. Preferably the second elongate spring member is made of a carbon fibre and resin composite material. 30          Preferably the second elongate spring member tapers from a thicker portion to a thinner portion towards the nose portion of the surfboard. Preferably the second elongate spring member tapers from a thicker portion to a thinner portion towards the tail portion of the surfboard. Preferably the second spring member has a width that 2019283772  16 Dec 2019 is greater than the thickness of the second spring member. Preferably the width is in the direction of the rails of the surfboard. Preferably the second elongate spring member has a thickness of substantially between 1mm to 5mm. More preferably the second elongate spring member has a thickness of substantially between 1mm to 3mm. Preferably the second elongate spring member has a width of substantially between 15mm to 200mm. Preferably the second elongate spring member has a width of substantially between 15mm to 80mm. More preferably the second elongate spring member has a width of substantially between 20mm to 40mm. Preferably the second elongate spring member tapers to a point at or towards the nose portion of the surfboard. Preferably the second elongate spring member tapers to a point at or towards the tail portion of the surfboard. Preferably the second elongate spring member comprises a plurality of layers of resilient material. Preferably the number of layers of resilient material define the thickness of the second elongate spring member. Preferably the number of layers of resilient material is greater in a central portion of the second elongate spring member compare to the second elongate spring member towards the nose portion of the surfboard, and compared to the second elongate spring member towards the tail portion of the surfboard. Preferably the plurality of layers of resilient material is between 2 to 8 layers of resilient material. More preferably the plurality of layers of resilient material is between 4 to 6 layers of resilient material. Preferably in use, the inner layer(s) of resilient material towards the core are / is shorter than the outer layer(s) of resilient material. Preferably each layer of the plurality of layers of resilient material has a different length. Preferably the plurality of layers are bonded together to form the second elongate spring member. More preferably the plurality of layers are bonded together using an epoxy to form the second elongate spring member. Preferably a thin portion of the second elongate spring member is less than 50% of the thickness compared to a thick portion of the second elongate spring member. Preferably the thin portion includes 1 to 2 layers of resilient material. Preferably the thick portion includes 4 to 6 layers of resilient material. In one embodiment, the second elongate spring member is pretensioned. Preferably the second elongate spring member is pretensioned in a first direction. Preferably the second elongate spring member is biased to bend towards the core. 2019283772  16 Dec 2019 Alternatively the first elongate spring member is pretensioned in a second direction, biased to bend away from the core. Preferably the second elongate spring member is formed in the channel in the lower surface of the core. Alternatively, the second elongate spring member is 5 pressed into the core to create the channel in the lower surface of the core. Preferably the first elongate spring member and the second elongate spring member are spaced from one another by the core. In another embodiment, the first elongate spring member and the second elongate spring member are connected by one or more connection members. 0          Preferably the surfboard includes a shell layer. Preferably the shell layer substantially covers the core. Preferably the shell layer substantially covers the first elongate spring member. Preferably the shell layer substantially covers the second elongate spring member. It will be understood that a shell layer may also be referred to as a skin layer. Preferably the shell layer includes a fibreglass and resin 5 composite material. Alternatively or additionally the shell layer can include a carbon fibre and resin composite material. Preferably the shell layer is bonded to the core. Preferably the shell layer is bonded to the first elongate spring member. Preferably the shell member is bonded to the second elongate spring member. Preferably the surfboard is between 170cm to 260cm in length. More 0 preferably the surfboard is between 180cm to 210cm in length. Preferably the surfboard has a partially concave lower surface. Preferably the surfboard has a partially convex upper surface. In another aspect, the present invention broadly resides in a surfboard having a core; and 25         a first elongate spring member located adjacent an upper side of the core; wherein the first elongate spring member extends substantially from a nose portion of the surfboard to a tail portion of the surfboard, and wherein the first elongate spring member has a width which is greater than a thickness of the first elongate spring member. 30          Preferably the width is in the direction of rails of the surfboard. Preferably the surfboard further includes a second elongate spring member located adjacent a lower side of the core. In a further aspect, the present invention broadly resides in a method of manufacturing a surfboard, including the steps of 2019283772  16 Dec 2019 shaping a foam core; forming a channel in a top surface of the foam core, the channel extending from a tail portion of the surfboard to a nose portion of the surfboard; inserting a first elongate spring member in the channel in the top surface of the foam core, such that the first elongate spring member is located adjacent the top surface of the core; and covering the foam core and the first elongate spring member with a shell layer. Preferably the method further includes the step of forming a channel in a lower surface of the foam core, the channel extending from a tail portion of the surfboard to a nose portion of the surfboard. Preferably the method further includes the step of inserting a second elongate spring member in the channel in the lower surface of the foam core, such that the second elongate spring member is located adjacent the lower surface of the core. Preferably the step of inserting a first elongate spring member in the channel in the top surface of the foam core includes forming the first elongate spring member in the channel in the top surface of the foam core. Preferably the step of inserting a second elongate spring member in the channel in the lower surface of the foam core includes forming the second elongate spring member in the channel in the lower surface of the foam core. Preferably the step of covering the foam core and the first elongate spring member with a shell layer includes covering the second elongate spring member with the shell layer. Preferably the surfboard is a surfboard as described in this specification. In another aspect, the present invention broadly resides in a surfboard having a core; and a second elongate spring member located adjacent a lower side of the core; wherein the second elongate spring member extends substantially from a nose portion of the surfboard to a tail portion of the surfboard, and wherein the second elongate spring member has a width which is greater than a thickness of the second elongate spring member. Preferably the width is in the direction of rails of the surfboard. Preferably the surfboard further includes a first elongate spring member located adjacent an upper side of the core. 2019283772  16 Dec 2019 In one embodiment, the surfboard is a paddleboard. The features described with respect to one aspect also apply where applicable to all other aspects of the invention. Furthermore, different combinations of described features are herein described and claimed even when not expressly stated. BRIEF DESCRIPTION OF THE DRAWINGS In order that the present invention can be more readily understood reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention and wherein: Figure 1 is a perspective top view of a surfboard according to an embodiment of the present invention; Figure 2 is a bottom perspective view of the surfboard of Figure 1; Figure 3 is a top view of the surfboard of Figure 1; Figure 4 is a bottom view of the surfboard of Figure 1; Figure 5 is a lateral section view of the surfboard of Figure 1; and Figure 6 is an exploded section view of the surfboard of Figure 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to Figures 1-6 there is shown a surfboard 10. The surfboard 10 has a core 12 made of foamed polyurethane. A first elongate spring member 14 is located adjacent an upper side 16 of the core 12. The first elongate spring member 14 is made of a plurality of layers (best seen in Figure 6) of unidirectional carbon fibre and resin. A second elongate spring member 18 located adjacent a lower side 20 of the core 12. The second elongate spring member 18 is made of a plurality of layers (best seen in Figure 6) of unidirectional carbon fibre and resin. The first elongate spring member 14 extends from a nose portion 22 of the surfboard to a tail portion 24 of the surfboard 10. The first elongate spring member 14 is located in a centrally located channel 26 in the upper surface 16 of the surfboard 10 (Figure 5 shows the channel 26 with the first elongate spring member 14 removed for clarity). The first elongate spring member 14 is formed in the channel 26 during the manufacture of the surfboard 10. 2019283772  16 Dec 2019 The first elongate spring member 14 has a width (in the direction of rails 30,32) that is greater than a thickness (depth) of the first elongate spring member 14. The second elongate spring member 18 extends from a nose portion 22 of the surfboard to a tail portion 24 of the surfboard 10. The second elongate spring 5 member 18 is located in a centrally located channel 28 in the lower surface 20 of the surfboard 10 (Figure 5 shows the channel 28 with the second elongate spring member 18 removed for clarity). The second elongate spring member 18 is formed in the channel 28 during the manufacture of the surfboard 10. The second elongate spring member 18 has a width (in the direction of rails 0   30,32) that is greater than a thickness (depth) of the second elongate spring member 18. The surfboard 10 includes a shell layer 34 which covers the core 12, the first elongate spring member 14 and the second elongate spring member 18. The shell layer 34 is formed of a fibreglass and resin composite material. 5 The surfboard also includes a plurality of fin boxes 40,42,44. The fin boxes 40,42,44 are inserted into the core 12 prior to the shell layer 34 covering the core 12. ADVANTAGES An advantage of the preferred embodiment of the surfboard includes 0 providing desired flex whilst enhancing longitudinal strength. Another advantage of the preferred embodiment of the surfboard includes the ability to control the amount and location of the flex by positioning the plurality of layers of the first and / or second elongate spring members in a desired location during the manufacture of the surfboard. A further advantage of the preferred embodiment of the surfboard 25 includes a reduction in torsional flex compared to a surfboard with a single centrally located stringer. VARIATIONS While the foregoing has been given by way of illustrative example of this 30 invention, all such and other modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as is herein set forth. 2019283772  16 Dec 2019 Throughout the description and claims of this specification the word “comprise” and variations of that word such as “comprises” and “comprising”, are not intended to exclude other additives, components, integers or steps.

Claims

1. A surfboard havinga core;5         a first elongate spring member located adjacent an upper side of the core; anda second elongate spring member located adjacent a lower side of the core; wherein the elongate spring members are pretensioned;wherein the first elongate spring member is located within a channel in the upper side of the core, and the second elongate spring member is located within a10 channel in the lower side of the core;wherein the first elongate spring member extends substantially from a nose portion of the surfboard to a tail portion of the surfboard, wherein the second elongate spring member tapers from the nose portion of the surfboard to a point at or towards the tail portion of the surfboard, and wherein each elongate spring member includes a15 plurality of layers of resilient material, wherein in use, the plurality of resilient material are bonded together to form each respective elongate spring member, and wherein the number of layers of resilient material is greater in a central portion of each respective elongate spring member compared to a portion of the respective elongate spring member towards the nose portion of the surfboard and compared to a portion20 of the respective elongate spring member towards the tail portion of the surfboard, and the plurality of layers of resilient material are arranged along the length of the surfboard and the inner layer(s) of resilient material towards the core are / is shorter than the outer layer(s) of resilient material so that there are more layers of resilient material in a central portion of the surfboard to make the central portion of the surfboard more25 resilient than each end of the surfboard, while maintaining strength along the length of the surfboard.

2. A surfboard as claimed in claim 1, wherein the first elongate spring member has a width which is greater than a thickness of the first elongate spring member, and30 wherein the second elongate spring member has a width which is greater than a thickness of the second elongate spring member.

3. A surfboard as claimed in any one of the preceding claims, wherein each elongate spring member is made of a carbon fibre composite material.2019283772   30 Sep 20264. A method of manufacturing a surfboard, including the steps ofshaping a foam core;forming a channel in a top surface of the foam core, the channel extending from5 a tail portion of the surfboard to a nose portion of the surfboard;forming a channel in a lower surface of the foam core, the channel tapering from the nose portion of the surfboard to a point at or towards the tail portion of the surfboard;inserting a pretensioned first elongate spring member in the channel in the top10 surface of the foam core, such that the first elongate spring member is located adjacent the top surface of the coreinserting a second elongate spring member in the channel in the lower surface of the foam core, such that the second elongate spring member is located adjacent the lower surface of the foam core,15          wherein the elongate spring members include a plurality of layers of resilientmaterial, wherein in use, the plurality of layers of resilient material are bonded together to form each respective elongate spring member, and wherein the number of layers of resilient material is greater in a central portion of each respective elongate spring member compared to a portion of the respective elongate spring member towards the20 nose portion of the surfboard and compared to a portion of the respective elongate spring member towards the tail portion of the surfboard, and the plurality of layers of resilient material are arranged along the length of the surfboard and the inner layer(s) of resilient material towards the foam core are / is shorter than the outer layer(s) of resilient material so that there are more layers of resilient material in a central portion25 of the surfboard to make the central portion of the surfboard more resilient than each end of the surfboard, while maintaining strength along the length of the surfboard; and covering the foam core and the first elongate spring member with a shell layer.

5. A method as claimed in claim 4, wherein the surfboard is a surfboard as claimed 30 in any one of claims 1 to 3.

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