WO2006021029A1

WO2006021029A1 - Improved surfboard fin box and fin attachment system

Info

Publication number: WO2006021029A1
Application number: PCT/AU2005/001260
Authority: WO
Inventors: John Decourcey Milne
Original assignee: DECOURCEY Pty Ltd
Current assignee: DECOURCEY Pty Ltd
Priority date: 2004-08-25
Filing date: 2005-08-24
Publication date: 2006-03-02
Anticipated expiration: 2007-02-25

Abstract

A surfboard fin box (21) for receiving a fin (11) having a fin body (12) and one or more structures (13) extending from an edge (15) of the fin body (12), includes a cavity (22) and bearing means (24) formed to bear a bearing force orientated in the elongate dimension against complementary bearing means (14) of the fin (11) and retain at least one of the structures (13) of the fin (11) inserted into the cavity (22).

Description

"IMPROVEDSURFBOARDFINBOXANDFINATTACHMENTSYSTEM"

FIELDOFINVENTION

THIS INVENTION relates to an improved surfboard fin box and fin attachment system. The invention is primarily directed to a fin box for the attachment of a fin to the body of a surfboard in such manner that the fin may be removed and replaced without the use of tools. However, the invention is not limited to this field of use.

BACKGROUNDART

The attachment of fins to surfboards (that is, the body of the surfboard) has been made the subject of some arrangements which permit the fin to be removed and replaced into a fin box, the fin box being permanently fixed in the body of the surfboard. Generally, arrangements have been aimed at providing for removable fins thereby providing for the attachment of different fins selected to suit different conditions in the surf or in the style of surfing to be performed. One example is disclosed in Australian Patent No. 657456, in which a removable fin system for surfboards and the like includes a fin having tabs extending from the proximal end which are receivable into complementary cavities of plugs embedded in the board. An obliquely extending grub screw is used to secure the fin by its tabs in the cavities by bearing against a side face of the tabs, one screw for each tab. The plugs can be in the form of a fin box, this latter being a common intermediate device used for attaching fins to boards. However, the angular orientation of the grub screw does not necessarily result in the securing force effected by the screw on the tabs of the fin acting in the most desirable fashion. Such an arrangement requires a tool to loosen and tighten the screw. Moreover, such an arrangement exerts in use a lateral "spreading" force on the sides of the fin box, generally in a direction towards which the fin box is weakest. A similar arrangement is disclosed in Australian Patent Specification No. 81502/94, except that the cavity into which the tab is inserted has a flexible wall against one side, a slot being provided on the other side of the flexible wall from the cavity and instead of a grub screw bearing directly against the side of the tab extension of the fin, a "fastener" in the form of a plug is insertable into the slot to prevent removal of the tab by preventing the flexible wall from flexing by virtue of the presence of the fastener in the slot. This arrangement also requires a tool to turn the screw, and relies on a similar lateral force to retain the fin in the fin box.

In Australian Patent Specification No. 707856, the tabs on the fin are cruciform in section and correspond to complementary cruciform-section cavities in respective plugs each acting as a kind of fin box. An oblique grub screw arrangement is provided in similar fashion to that of Australian Patent No. 657456 hereinbefore described, except that each respective grub screw bears against one of the lateral faces of the respective tabs of the fin.

In Australian Patent Specification No. 34367/02, a fin box is provided having the same arrangement, except that by a simple combination of the arrangements of Australian Patent No. 657456 and Australian Patent Specification No. 81502/94, the oblique grub screw bears against a flexible wall interposed between the cavity into which the tab of a fin is receivable and a slit to provide for movement of the flexible wall when the grub screw is inserted therein to bear against face of the flexible wall remote from the cavity.

It can be seen that in all of the arrangements which include a grub screw or the like, a tool separate from the surfboard is required to remove and replace the fin. Such _ 2 _

arrangements often rely on a lateral force being resisted by the side walls of a fin box, whereby the side walls are generally required to be strengthened structurally to accommodate the forces applied by the screw.

The present invention aims to provide an improved surfboard fin attachment system which alleviates one or more of the disadvantages of the prior art. Other aims and advantages of the invention may become apparent from the following description.

DISCLOSUREOFTHEINVENTION

With the foregoing in view, this invention in one aspect resides broadly in a surfboard fin attachment system including:

a fin box having

a body extending in an elongate dimension, a transverse dimension substantially at right angles to the elongate dimension and a depth dimension generally at right angles to the elongate and transverse dimensions;

an open cavity extending into the body in the depth dimension, the orifice of the cavity being defined by a fin box outer face;

bearing means formed to bear a bearing force oriented substantially in the elongate dimension;

and a fin having

a fin body and one or more structures extending from an edge of the fin body,-

the one or more structures being formed to be received into the cavity of the fin box such that the edge from which the one or more structures extend may substantially mate with the fin box outer face; complementary bearing means operably associated with the one or more structures and co-operable with the bearing means of the fin box;

said bearing means and complementary bearing means being arranged to provide a retaining force on the or at least one of the structures in the depth dimension when the edge of the fin from which the one or more structures extend is substantially mated against the fin box outer face.

In another aspect, this invention resides broadly in a surfboard fin box to which a fin may be attached, the fin being of the type having a fin body and one or more structures extending from an edge of the fin body, the one or more structures being formed to be received into a cavity of a fin box such that the edge from which the one or more structures extend may substantially mate with the fin box outer face, said fin box including:

an open cavity extending into the body in the depth dimension, the orifice of the cavity being defined by a fin box outer face, being the cavity for receiving the structures extending from the edge of the fin; and

and wherein the structures of said fin include complementary bearing means arranged to co-operate with the bearing means of the fin box, said bearing means and complementary bearing means being arranged to provide a retaining force on the or at least one of the structures in the depth dimension when the edge of the fin from which the one or more structures extend is substantially mated against the fin box outer face.

Preferably the bearing means includes two substantially rigid compression members mounted pivotally to a bearing support for pivotal motion back and forth in the depth dimension about a common pivot axis running in the transverse dimension. Preferably, the distal end of each compression member is engageable with a bearing face formed on or in the structure or structures extending from the fin body. In such form, the opposed bearing faces are arranged such that when the fin is placed in operative disposition with respect to the fin box, ready for insertion of the structures extending from the fin body into the cavity of the fin box, the distal ends of the compression members both engage with the opposed faces, the lengths of the compression members and the spacing between the opposed faces being selected to provide an interference fit of the compression members between the opposed faces when the compression members are substantially coaxial, but that at least some of the compression is relived when the compression members are pivoted further into the cavity by virtue of the further insertion of the fin into the fin box. In such form, the compression members, being arranged in opposed pairs, generally provide a reactive force against compression thereof in the elongate dimension, the compression of the compression members being provided by the disposition of the structures extending from the fin body together with the selected spacing between the opposed faces on or in the structure or structures extending from the fin body. Preferably, the size, spacing and pivoting arrangement of the compression members, together with the dimensions of the cavity of the fin box, are selected to accommodate current fin designs wherein typically the structure or structures extending from the fin body are constituted by a pair of tabs generally formed as rectangular prisms of relatively thin form, the thin dimension being substantially commensurate with the thickness of the fin body.

In an alternative form, the compression members may include a rigid portion and a flexible portion in operative association with the mounting to provide the pivotal motion of the compression member described above. However, it is preferred that the compression members are formed from substantially rigid material and pivoted on a hinge pin or the like mounted in the transverse dimension to provide pivoting about an axis in the transverse dimension for relative motion of the distal ends of the compression members back and forth in the depth dimension.

Although arrangements according to the invention may be conceived for providing the bearing and complimentary bearing means with an arrangement where the compression forces described above are negative, it is preferred that a simple lever arrangement be provided the arrangement being such that engagement of the opposed faces causes the lever arms to engage the distal ends and by pivoting from a position at which the spacing between the distal ends is at least slightly smaller than the maximum dimensions in the elongate dimension between the distal ends, a force in the depth dimension after engagement of the distal ends of the lever arms with the opposed faces of the structure or structures beyond an "over centre" position, provides that the lever arms provide a net force in the depth dimension to retain the fin in its appropriate position with respect to the fin box.

In a further preferred form, the central mount is slidable along an axis substantially aligned with the elongate dimension whereby the fin may be mounted to the fin box in a selected disposition with respect to the elongate dimension, the locking of the fin into the fin box by operative engagement of the bearing means and complimentary bearing means also locking the central mount against movement in the elongate dimension. It is further preferred that in such form, the central mount be arranged in sliding engagement with a slot having a slight curvature in the elongate dimension to provide for the body of the fin to be oriented within a range of selected angles by mounting the fin in the fin box within a range of selected dispositions in the elongate dimension.

In a preferred form, the edge from which the structures extend is preferred dimensioned such that it substantially encloses the orifice of the cavity in the fin box, thereby substantially hiding all of the mechanisms constituting the bearing means and complimentary bearing means from view when the fin is in its seated position in the fin box.

BRIEFDESCRIPTIONOFTHEDRAWINGS

In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate preferred embodiments of the invention and wherein: -

Fig. 1 is a diagrammatic partial sectional view from the side of a surfboard fin attachment system according to the invention, shown with the fin spaced from the cavity of the fin box;

Fig. 2 is a diagrammatic partial side view of the surfboard fin attachment system of Fig. 1 with the fin partially inserted into the fin box; Fig. 3 is a diagrammatic partial side view of the surfboard fin attachment system of Figs. 1 and 2 with the fin fully inserted in the fin box;

Fig. 4 is a plan view of the fin box of Figs. 1 to 3 without the fin attached;

Fig. 5 is a plan view of the fin and fin box of the surfboard fin attachment system with the fin inserted or partly inserted into the fin box;

Fig. 6 is diagrammatic partial side view of an alternative surfboard fin attachment system according to the invention, shown with the fin spaced from the fin box,-

Fig. 7 is a diagrammatic partial side view of the alternative surfboard fin attachment system of Fig. 6 shown with the fin fully inserted in the fin box;

Fig. 8 is a diagrammatic partial side view of a third surfboard fin attachment system according to the invention with the fin spaced from the fin box,-

Fig. 9 shows the third surfboard fin attachment system of Fig. 8 with the fin fully inserted in one position;

Fig. 10 shows the third alternative surfboard fin attachment system of Fig. 9, but in a different position in the elongate dimension;

Fig. 11 is diagrammatic transverse sectional view of the third alternative surfboard attachment system of Figs. 8 to 10; Fig. 12 is a diagrammatic partial side view of a fourth surfboard fin attachment system according to the invention with the fin spaced from the fin box;

Fig. 13 shows the fourth surfboard fin attachment system of Fig. 12 with the fin fully inserted;

Fig. 14 is a diagrammatic partial side view of a fifth surfboard fin attachment system according to the invention with the fin spaced from the fin box,-

Fig. 15 shows the fifth surfboard fin attachment system of Fig. 14 with the fin fully inserted; and

Fig. 16 is diagrammatic sectional plan view of the fifth alternative surfboard attachment system of Figs. 14 and 15.

It will be appreciated that since the fin or fins of a surfboard are provided oh the underside of the board, the arrangements being depicted in the drawings are shown upside down only for the purpose of clarity of disclosure.

DETAILEDDESCRIPTIONOFTHEDRAWINGS

The surfboard fin attachment system 10 shown in Figs. 1, 2 and 3 includes a fin 11 having a fin body 12 and a structure 13 extending from one edge 15 of the fin body. The structure is formed to provide opposed bearing faces 14 spaced from one another generally in the elongate dimension as indicated by arrow 16. The system further includes a fin box 21 mounted in a surfboard body 20, the fin box having a cavity 22 extending therein in the depth dimension and being elongate in the elongate dimension, the cavity having an orifice defined by a fin box outer face 23. Two opposed lever arms 24 are mounted to a pivot 25 for pivotal movement in the direction of arrows 27 back and forth in the depth dimension, each lever arm ending at a distal end 26 spaced from the pivot a distance commensurate to provide an interference fit of the two lever arms between the opposed bearing faces of the structure of extending from the edge of the fin body so that, as can be seen in Fig. 2, insertion of the fin into the cavity of the fin box in the direction of arrow 17 causes displacement and/or compression of part of the structure and/or compression or deflection of the lever arms to accommodate the excess length thereof between the opposed bearing faces, but further insertion until the edge of the fin body meets the fin box outer face, the lever arms bearing having their respective distal ends bearing against the opposed bearing faces of the structure provide a net force in the direction of arrow 18.

The arrangement is shown in plan view in Fig. 4 of the fin box, it being appreciated that in all of the views shown in all of the figures, a fin is generally attached to the underside of a surfboard. In use, thus, the drawings representing the fin, surfboard body and associated parts are shown upside down with respect to their normal orientation.

In the alternative surfboard fin attachment system 30 shown in Figs. 6 and 7, the fin body has an alternative structure depending therefrom to form the alternative fin for engagement with an alternative fin box 41 having an alternative cavity 42 in two parts in which alternative lever arms 44 are mounted to alternative pivots 45 for engagement with alternative opposed bearing faces 34 on the alternative structures, the arrangement being similar to that of the surfboard fin attachment system 10 of Figs. 1 to 5 with the exception that the lever arms are provided separately on separate pivot points and bear towards one another against the alternative opposed bearing faces, whereas the lever arms of the surfboard fin attachment system 10 shown in Figs. 1 to 5 has the lever arms bearing away from one another. In the third alternative surfboard fin attachment system 50 shown in Figs. 8 to 11, the fin and its associated fin body and fin structure are substantially the same as that shown in Figs. 1 to 3 and accordingly, the same reference numerals are used to indicate the same parts and elements thereof. However, the third alternative fin box 51 is arranged with a slot 53 to permit a separate pivot mounting post 54 to slide in the elongate dimension indicated by arrow 16, the arrangement working in the same fashion as that described in relation to the surfboard fin attachment system of Figs. 1 to 5, but with the added feature that once the fin is engaged in the fin box cavity, the over centre clamping force, in addition to holding the fin in the cavity in the direction of arrows 18 also retains the mounting post in fixed relationship to the slot by having it bearing relatively upwards (in the orientation shown) in the direction of arrow 19.

In the fourth and fifth alternative surfboard fin attachment systems 60 and 70 respectively shown in Figs. 12 to 16, the fin and its associated fin body and fin structure are substantially the same as that shown in Figs. 1 to 3 and accordingly, the same reference numerals are used to indicate the same parts and elements thereof. However, the forth alternative fin box 61 is arranged with a sloping end wall 62 against which a sliding block 53 can slide in the direction of arrows 66. The sliding block includes a penetration 64 substantially parallel to the sloping wall. Once the fin has been inserted into the slot, a screw or the like may be inserted into and through the penetration and into a fin box penetration 65 in the direction of arrow 67. The direction of arrow 67 includes a component in depth dimension and the elongate dimension as represented by the composite arrow 68, the elongate dimension indicated by arrow 69. In relation to the fifth surfboard fin, two skew apertures 72 are provided through the fin box 71 with an opening to the outer face of the fin box beside the slot and extending to penetrate an inner wall of the fin box at a location at which each meets one of the opposed bearing faces of the fin. A screw 73 threadedly inserted into each skew aperture, thereby engaging against each opposed bearing face of the fin, and it can be seen a component of the direction of the skew aperture is in the elongate dimension.

In use, a fin may be attached to the underside of a surfboard body to form a finned surfboard by providing a fin box having the levers as described biased towards a receiving position substantially as shown in respect of Fig. 1. The biasing may be achieved by a spring or the like, or by having the lever arms arranged with a flexible arrangement. The structures extending from the body of the fin, protrusions, include bearing faces to engage with the distal ends of the lever arms, and insertions of the fin causes the distal ends of the lever arms to engage with the opposed bearing faces to permit the fin to be retained in the cavity after a snap fit function is actuated by operative insertion of the fin into the cavity. The fin may be removed from the fin box by application of sufficient force to overcome the compression of the lever arms against the bearing faces.

Although it will be seen that providing only one lever arm will achieve the same overall result, it is believed that the provision of two lever arms provides a more balanced outcome. In the arrangements shown in Figs. 8 to 11, the fin may be placed at the desired position in the elongate dimension, and if the slot is provided in curved form, then the angle of the fin body may be adjusted with respect of the surfboard body to accommodate surfing in different conditions and/or different surfing styles. In the case of the alternative embodiments shown in Figs. 12 to 16, the fin is inserted into the aperture prior to tightening up screws either to move the blocks or to bear directly against the bearing faces, but it will be appreciated that such arrangements have the disadvantage that the user is required to have a tool for fixing or removing the fin from the fin box.

Although the invention has been described with reference to one or more specific examples, it will be appreciated by persons skilled in the art that the invention may be embodied in other forms which are encompassed within the broad scope and ambit of the invention as claimed by the following claims.

Claims

1. A surfboard fin box to which a fin may be attached, the fin being of the type having a fin body and one or more structures extending from an edge of the fin body, the one or more structures being formed to be received into a cavity of a fin box such that the edge from which the one or more structures extend may substantially mate with the fin box outer face, the structures of said fin include complementary bearing means arranged to bear a bearing force thereagainst, said fin box including:

bearing means formed to bear a bearing force oriented substantially in the elongate dimension against the complementary bearing means of the fin;

said bearing means and said complementary bearing means co¬ operating to provide a retaining force on the or at least one of the structures are inserted into said cavity for retaining said structures against removal from said cavity.

2. A surfboard fin box to which a fin may be attached, the fin being of the type having a fin body and one or more structures extending from an edge of the fin body, the one or more structures being formed to be received into a cavity of a fin box such that the edge from which the one or more structures extend may substantially mate with the fin box outer face, said fin box including:

an open cavity extending into the body in the depth dimension, the orifice of the cavity being defined by a fin box outer face, being the cavity for receiving the structures extending from the edge of the fin,- and

3. A fin box according to Claim 1 or Claim 2, wherein the bearing means includes two substantially rigid compression members mounted pivotally to a bearing support for pivotal motion back and forth in the depth dimension about a common pivot axis running in the transverse dimension.

4. A fin box according to any one of the preceding claims, wherein the distal end of each compression member is engageable with a bearing face formed on or in the structure or structures extending from the fin body, each bearing face being in opposed disposition with respect to the other.

5. A fin box according to Claim 4, wherein the lengths of the compression members and the spacing between the opposed faces are selected to provide an interference fit of the compression members between the opposed faces when the compression members are substantially coaxial and the fin is partially inserted into the cavity, but that at least some of the compression is relived when the compression members are pivoted further into the cavity by virtue of the further insertion of the fin into the fin box.

6. A fin box according to Claim 5, wherein the size, spacing and pivoting arrangement of the compression members, together with the dimensions, of the cavity of the fin box, are selected to accommodate fin designs wherein the. structure or structures extending from the fin body are constituted by a pair of tabs formed as rectangular prisms dimensioned substantially commensurate with the thickness of the fin body.

7. A fin box according to any one of Claims 3 to 6, wherein the compression members are formed from substantially rigid material and pivoted on a hinge pin mounted in the transverse dimension to provide pivoting about an axis in the transverse dimension for relative motion of the distal ends of the compression members back and forth in the depth dimension.

8. A fin box according to any one of the preceding claims, wherein the edge from which the structures of the fin extend is dimensioned such that said edge substantially encloses the orifice of the cavity in the fin box.

9. A surfboard fin attachment system comprising the fin being operatively attachable to the fin box according to any one of the preceding claims .

10. A surfboard fin attachment system including:

a fin box having

an open.cavity extending into the body in the depth dimension, the orifice of the cavity being defined by a fin box outer face;

and a fin having

a fin body and one or more structures extending from an edge of the fin body;

the one or more structures being formed to be received into the cavity of the fin box such that the edge from which the one or more structures extend may substantially mate with the fin box outer face,- complementary bearing means operably associated with the one or more structures and co-operable with the bearing means of the fin box;