EP1446321A1

EP1446321A1 - Removable and adjustable surf fin system

Info

Publication number: EP1446321A1
Application number: EP02776595A
Authority: EP
Inventors: William Thomas Mccausland; Graeme Bennett; Gary Mountford
Original assignee: Sunbum Pty Ltd
Current assignee: Sunbum Pty Ltd
Priority date: 2001-11-13
Filing date: 2002-11-12
Publication date: 2004-08-18
Also published as: US20030092334A1; CN1608016A; JP2005508798A; WO2003042031A1

Abstract

A removable fin mounting assembly comprising a fin (20), a fin plug assembly (24), a cam and a worm gear. The fin plug assembly (24) defines a cavity (40) adapted to receive a portion of said fin (20). The cam has gears and is positioned within the fin plug assembly (24) adjacent to the cavity (40). The worm gear is positioned within the fin plug assembly (24) and adapted to engage with said gears of the cam. Turning said worm gear causes the cam to rotate and secure said portion of the fin (20) received in the cavity (40).

Description

REMOVABLE AND ADJUSTABLE SURF FIN SYSTEM [0001] Field of the Invention:

[0002] This invention relates to a removable and adjustable fin system for surfcraft such as surfboards, and a method for installing the fin system on a surfboard. [0003] Background of the Invention

[0004] In the manufacture of surfboards, a body of plastic foam material is shaped and then covered with a layer of fibre-reinforced resin, normally fibreglass. The body of surfboards has an upper side or ride surface for supporting a surfer and a lower surface that is directed into the water. One or more fins, most commonly three, are fixed to the body of the surfboard on the lower surface. The fins may be fixed permanently to the board, for example, by utilising fibre-reinforced resin around the base of the fin.

[0005] There are, however, many disadvantages to permanently mounting a fin to a surfboard in that the fin cannot be easily removed and replaced when the fin is damaged or when it is desirable to replace the fin with another fin having different hydrodynamic performance properties. Further, it may be desirable to remove the fins to minimise the potential for damage to the surfboard or to the fins during transport and storage. In order to accommodate removal and overcome the disadvantages of permanent mounting, fin assembly systems that allow removal of the fins from the surfboards have been developed. Such removable fin systems are disclosed, for example, in the United States Patent Nos. 5,328,397 and 5,975,974. The removable fin systems known in the art have shortcomings, however, and there is room for improvement.

[0006] The existing fin systems require physical manoeuvring, i.e. loosening of small grub screws, before the fins can be installed or removed from the surfboard. Further, in most systems, an Allen key or other special tool is required and damage or corrosion of the grub screws may make the removal and replacement process difficult and time consuming. In addition, existing systems do not provide for an easy adjustment of the fins once installed. It is often desirable to change the f re-aft position of the fins, in particular, the rear or centre fin, depending on the surf conditions and the desired surfboard performance. Current fin systems are designed for fixed or limited positions where the fins are inserted and secured, and provide no or difficult adjustment capability to move the fins forward or backward once installed.

[0007] Other problems associated with existing systems relate to the installation of the fin fixing system into the body of the surfboards. The two-plug fixing system as described in the United States Patent No. 5,328,397, for example, requires the accurate alignment of the plugs at a predetermined spacing of the plugs during the installation process. Any slight offset of the plugs may result in a less than perfect alignment of the plugs and could make it difficult or impossible to install the fins. The plugs could also lose alignment due to physical stress and tempering on the surfboards during the installation process. Further, the installation methods known in the art often require multiple marking and positioning jigs or templates and other tools and accessories, i.e. putty, tape, foam, centre punch, etc. More significantly, conventional installation methods typically involve multiple steps of marking, positioning, removal and repositioning of the jigs or templates, and are often difficult and time-consuming. It would therefore be desirable to have a complete control jig system that would allow an easy and accurate installation of a fin fixing system. [0008] Therefore, there is a need for a fin fixing system that allows a convenient and quick installation, removal, and adjustment of the fins. An installation jig system that would allow an easy and accurate installation of a surf fin fixing system in a surfboard would also be a useful improvement.

[0009] The applicant does not concede that the prior art discussed in the specification forms part of the common general knowledge in the art at the priority date of this application.

[00010] Summary of the Invention

[00011] The present invention provides a removable fin mounting assembly comprising: a fin; a fin plug assembly defining a cavity adapted to receive a portion of said fin; a cam having gears, said cam positioned within said fin plug assembly adjacent to said cavity; and a worm gear positioned within said fin plug assembly and adapted to engage with said gears of said cam, wherein turning said worm gear causes said cam to rotate and secure said portion of said fin received in said cavity.

[00012] The fin can further comprises a tab wherein said tab is received in said cavity.

[00013] The length of said cavity can be greater than the length of said tab allowing a fore-aft adjustment of said fin within said cavity.

[00014] The cam can further comprise a flat portion and a bulging portion.

[00015] Turning said worm gear in one direction will rotate said cam to an engaging position while turning said worm gear in an opposite direction rotates said cam to a disengaging position.

[00016] The bulging portion of said cam can be aligned with said fin in said engaging position while said flat portion of said cam can be aligned with said fin in said disengaging position. The bulging portion can include a rubber material.

[00017] The worm gear can further comprise an opening adapted to receive a means for turning said worm gear. The opening can be substantially rectangular and said means for turning

[00018] The fin include a rubber material. The fin can have a side surface, said side surface being adjacent to said cam when said fin is received in said cavity. The fin can also have a side surface having a concave portion, said concave portion being adjacent to said cam when said fin is received in said cavity. Alternatively, the fin can have a side surface having a cut out portion, said cut out portion being adjacent to said cam when said fin is received in said cavity.

[00019] The fin mounting assembly as described above can further comprise an upper part and a lower part, wherein said upper part includes a plurality of supporting arms.

[00020] The fin plug assembly can be adapted to be embedded in a body of a surfcraft.

[00021] The worm gear can be positioned vertically.

[00022] The fin can be adapted to move fore-aft within said cavity, with the cavity having built-in tilt angle.

The built-in tilt angle can be 3° to 5°.

[00023] The present invention also provides a fin comprising: a body portion defining a hydrodynamic foil, said body portion configured to extend generally perpendicularly relative to a lower surface of a surfcraft; and a mounting portion attached to said body portion, said mounting portion configured to be received and frictionally held in a cavity defined by a fin plug assembly embedded in said surfcraft. [00024] The mounting portion can include a soft, malleable material. The soft, malleable material is preferably rubber. The mounting portion can include at least one tab. The tab can extend away from said fin. The fin can have a first side with a sloping undercut adapted to engage with a fin plug assembly. [00025] The tab can have a second side, where at least a portion of the second side is corrugated and adapted to associate with a sidewall formed within a cavity. The portion of the second side of the tab that is corrugated can also or alternatively be located on a front portion.

[00026] The portion of the second side of the tab that is corrugated can also or alternatively be located on a back portion.

[00027] The portion of the second side of the tab that is corrugated can also or alternatively be located on a middle portion.

[00028] The portion of the second side of the tab that is corrugated can also or alternatively be located substantially the second side.

[00029] The second side can be corrugated to form a sine wave. The second side can also or alternatively be corrugated to form a saw-tooth configuration.

[00030] The present invention also provides a combination of a fin mounting assembly as described above, with a fin as described above.

[00031] The invention further provides a method of installing a fin plug assembly in a surfcraft comprising: positioning a complete control jig system on a lower surface of said surfcraft where said fin plug assembly is to be embedded; removing a centre portion of said complete control jig system; creating a mounting cavity within said surfcraft, said mounting cavity having a substantially same shape and size as said centre portion; positioning said fin plug assembly within said mounting cavity, wherein said fin plug assembly has a plurality of supporting arms; removing depth cut outs of said complete control jig system; aligning and positioning said supporting arms of said fin plug assembly into said depth cut outs; filling said mounting cavity with a resin; and sanding off said complete control jig system, a top surface and said supporting arms of said fin plug assembly.

[00032] The method can further comprise: fitting a dummy fin into said fin plug assembly; and placing a variable amount of putty into said depth cut outs and adjusting a vertical tilt angle of said fin plug assembly.

[00033] The centre portion and said depth cut outs can be pre-cut. The centre portion can be in a substantially similar shape as an outline of said fin plug assembly.

[00034] The method can further comprise removing materials extending from said mounting cavity and creating a space for said resin to fill. This space can extend substantially to a skin- of an upper surface of said surfcraft.

[00035] The present invention also provides a system for releasably securing a tab of a fin, comprising: a fin plug assembly having a cavity adapted to receive a tab extending from a fin; a worm gear having teeth adapted to rotate within the fin plug assembly; a cam between the worm gear and the cavity, where the cam is adapted to engage with the teeth of the worm gear such that rotation of the worm gear causes the cam to engage with the tab of the fin within the cavity. [00036] The tab can have a first side with a sloping undercut adapted to engage with the cam, where rotation of the worm gear causes the cam to engage with the sloping undercut to secure the tab within the cavity of the fin plug assembly.

[00037] The counter rotation of the worm gear can cause the cam to release the sloping undercut of the tab within the cavity. Preferably the sloping undercut extends to a base of the tab. The sloping undercut can also terminate above a base of the tab.

[00038] The tab can have a second side, where at least a portion of the second side is corrugated, with the cavity having a side wall adapted to associate with the second side of the tab that is corrugated.

[00039] The portion of the second side of the tab that is corrugated is on a front portion.

[00040] The portion of the second side of the tab can also or alternatively be corrugated on a back portion

[00041] The portion of the second side of the tab can also or alternatively be corrugated on a middle portion.

[00042] The portion of the second side of the tab can also or alternatively be corrugated on substantially the second side.

[00043] The second side can be corrugated to form a sine wave. The second side can also or alternatively be corrugated to form a saw-tooth configuration.

[00044] The invention further provides a system for engaging a fin to a surfcraft, comprising: a worm gear having teeth adapted to be actuated within a fin plug assembly that has a cavity adapted to receive a tab extending from a fin, where actuation of the worm gear causes the tab to be secured within the cavity.

[00045] The system can further include a cam between the tab and the worm gear, where the cam have teeth to engage with the teeth of the worm gear.

[00046] The invention also provides a system for engaging a fin to a surfcraft, comprising: a worm gear having teeth adapted to actuate within a fin plug assembly; and a tab having a first side adapted to engage with the teeth of the worm gear, where rotation of the worm gear causes the tab to secure within the cavity.

[00047] The first side of the tab can have a thread that engages with the teeth of the worm gear that causes the tab to secure within the cavity with the rotation of the worm gear.

[00048] The first side of the tab can have an undercut that engages with the teeth of the worm gear that causes the tab to secure within the cavity with the rotation of the worm gear. The teeth can have a pitch angle that increases with rotation of the worm gear to engage the undercut on the first side of the tab to secure the tab within the cavity with the rotation of the worm gear.

[00049] The longitudinal axis of the worm gear can be substantially parallel with the longitudinal axis of the tab.

[00050] A counter-rotation of the worm gear can cause the tab to be released from the cavity.

[00051] The invention can also provide a system for engaging a fin for a surfcraft, comprising: a worm gear having teeth adapted to actuate in a fin plug assembly that has a cavity adapted to receive a tab extending from a fin; and a cam between the worm gear and the cavity, where the cam is adapted so that actuation of the worm gear causes the cam to engage with the tab from the fin.

[00052] The cam can have teeth to engage with the teeth of the worm gear. [00053] The invention further provides a method for engaging a fin to a surfcraft, comprising: forming a tab protruding from a fin for a surfcraft; inserting the tab into a cavity formed within a plug assembly formed within a surfcraft; and engaging a side of the tab within the plug assembly to secure the fin to the surfcraft.

[00054] The method can also include: undercutting the side of the tab to engage with a cam within the plug assembly; and actuating a worm gear that causes the cam to engage with the undercutting.

[00055] The method can also include: threading the side of the tab; actuating the worm gear that has teeth; and engaging the teeth of the worm gear to the threading to hold the tab within the cavity.

[00056] The method can further including: undercutting the side of the tab; increasing a pitch angle of a teeth on a worm gear; rotating the worm gear to engaging the teeth with the undercutting on the side of tab to engage the tab within the plug assembly.

[00057] The present invention also provides a surfcraft having: a removable fin mounting assembly as described above; a fin as described above; a combination of a fin and fin mounting assembly as described above; a system for engaging a fin as described above; a fin which engages the surfcraft by the method described above; or a fin plug assembly installed by the method described above. The said surfcraft can be a surfboard.

[00058] Other systems, methods, and features of the invention will be or will become apparent to one with skill in the art upon examination of the following Figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims.

[00059] Brief Description of the Drawings

[00060] The invention can be better understood with reference to the following Figures. The components in the Figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the Figures, like reference numerals designate corresponding parts throughout the different views.

[00061] Figure 1 is an exemplary view illustrating how fins are installed in fin plug assemblies on the lower surface of a surfboard according to one embodiment of the present invention;

[00062] Figure 2 is a cross sectional view of the fin plug assembly and the fin of Figure 1 along the line 2-2 in Figure 1;

[00063] Figure 3 is a perspective top view of the fin plug assembly according to one embodiment of the invention;

[00064] Figure 4 is a cross sectional view of the fin plug assembly along the line 4-4 in Figure 3 according to one embodiment of the present invention;

[00065] Figure 5 is a cross sectional view of the fin plug assembly along the line 4-4 in Figure 3 according to another embodiment of the present invention;

[00066] Figure 6 is a cross sectional view of the fin plug assembly along the line 4-4 in Figure 3 according to yet another embodiment of the present invention;

[00067] Figure 7 is a perspective inside view of the fin plug assembly according to one embodiment of the invention; [00068] Figure 8 is a perspective view of a complete jig system according to one embodiment of the invention;

[00069] Figure 9 is another perspective view of the complete jig system according to one embodiment of the invention; and

[00070] Figure 10 is an exemplary view of the fin plug assemblies and a centre fin according to one embodiment of the present invention;

[00071] Figure 11 is a cross sectional view of the surfboard and a mounting cavity formed therein according to one embodiment of the present invention;

[00072] Figure 12 is a cross sectional view of a fin plug assembly engaging a tab with an undercut;

[00073] Figure 13 is a cross sectional view of a fin plug assembly engaging a tab with a modified undercut;

[00074] Figure 14 is a side view of a fin;

[00075] Figure 15 is a bottom view of the fin;

[00076] Figure 16 is a top view of a tab having corrugation inserted into the cavity of a fin plug assembly;

[00077] Figure 17 is a top view of a fin plug assembly engaging a tab;

[00078] Figure 18 is a bottom view of a tab having a corrugation on the front portion of the tab;

[00079] Figure 19 is a bottom view of a tab having a corrugation on the backside of the tab;

[00080] Figure 20 is a bottom view of a tab having corrugation along certain portions of the tab;

[00081] Figure 21 is a side view of a fin having corrugation along the longitudinal axis of the tab;

[00082] Figure 22 is a top view of a fin plug assembly where the tab of the fin and the cavity formed in the fin plug assembly engaging to lock in place.

[00083] Figure 23 is another embodiment of a fin plug assembly; and

[00084] Figure 24 is still another embodiment of a fin plug assembly.

[00085] Detailed Description of the Preferred Embodiments

[00086] This description is not to be taken in a limiting sense, but is made for the purpose of illustrating the general principles of the invention. The section titles and overall organisation of the present detailed description are for the purpose of convenience only and are not intended to limit the present invention. [00087] Figure 1 illustrates by way of example how fins 20, 30 are installed in a surfboard 22 using fin plug assemblies 24 of the present invention. Figure 1 shows a lower surface 26 of a surfboard 22 which is received in the water. The other side of the surfboard (not shown) is an upper ride surface for supporting a surfer. A centre or rear fin 30 as well as two side fins 20 may be installed into the fin plug assemblies 24 (shown by dotted lines). The fin plug assemblies 24 for both the rear fin 30 and the side fins 20 may have the same size, but typically the fin plug assembly 24 for the rear fin 30 is larger than the fin plug assembUes 24 for the side fins 20 as shown in Figure 1.

[00088] Generally, the side fins 20 and the rear fin 30 have an end surface 32 and one or more tabs 34 extending from the end surface 32. The tab 34 is configured to be received in a cavity 40 of the fin plug assembly 24, and the side fin 20 or the rear fin 30 is secured within the fin plug assembly 24 by inserting a key 60 into a slot 64 (Figure 3) of a worm gear 62 and turning the key 60. When the side fin 20 or the rear fin 30 is properly installed, the end surface 32 preferably abuts against the fin plug assembly 24 and sits substantially flush with the lower surface 26 of the surfboard 22 and a top surface 74 (Figure 3) of the fin plug assembly 24.

[00089] In Figure 1, the rear fin 30 is depicted in a position at the far rear end of the cavity 40. However, by making the longitudinal length of the cavity 40 longer than that of the tab 34 of the rear fin 30, the fin 30 may be moved and positioned fore and aft within the cavity 40. The fore-aft movement/adjustment can be made quickly and easily, even in the surf. The side fins 20 may also be moved and positioned fore and aft within the cavity 40 in the same manner as described above.

[00090] The fore-aft movement/adjustment is more clearly demonstrated with reference to Figure 2, which shows a cross-sectional view of the fin plug assembly 24 and the rear fin 30 along the line 2-2 of Figure 1. In one embodiment of the present invention, the fin plug assembly 24 allows the fore-aft movement of the rear fin 30 up to around 15 mm. The fore-aft movement of the side fins 20 is usually more restricted, allowing for displacement of only up to around 5 mm. The 5-15 mm movement allowance is, however, not absolute and a greater or lesser allowance may be easily achieved by either making the cavity 40 longer or the tab 34 shorter.

[00091] The cross sectional view in Figure 2 shows the rear fin 30 with the tab 34 received in the cavity 40. The end surface 32 of the fin may abut against and sit substantially flush with a portion of the lower surface 26 of the surfboard 22 and the top surface 74 of the fin plug assembly 24. As shown in Figure 2, the rear fin 30 may be moved forward or backward along the direction indicated by the arrow 27, and the rear fin 30 may be moved to the foremost position or anywhere between the fore and aft positions, and locked in place. [00092] Figure 3 shows a perspective top view of the fin plug assembly 24 according to one embodiment of the present invention. The fin plug assembly 24 is to be embedded into the surfboard 22 as shown in FIGS. 1 and 2. As shown in Figure 3, the fin plug assembly 24 has the cavity 40 to receive the fin 20, 30, and a worm gear 62 with a generally rectangular shaped slot 64 to receive a key 60 (shown in Figure 1). The fin plug assembly 24 in Figure 3 is generally shaped as three overlapping cylinders, and has three temporary supports or outriggers 66 for positioning the fin plug assembly 24 on the lower surface 26 of the surfboard 22 during installation. The fin plug assembly 24 also has a plurality of recesses 70 and a collar 72 projecting upwardly from the top surface 74 thereof around the peripheral edge of the fin plug assembly 24. The role of the outriggers 66, recesses 70 and the collar 72 will be discussed in more detail hereinafter.

[00093] Different shapes, i.e. rectangular, oval, square, etc., for the fin plug assembly 24 may be used, and the three overlapping cylinder shape of the fin plug assembly 24 is not meant to be restrictive or limiting. [00094] The details of the fin plug assembly 24 and the operation and inter-relationship between the worm gear 62 and an associated cam 80 are illustrated by an exemplary cross sectional view shown in Figure 4. The worm gear 62 is vertically aligned within the fin plug assembly 24. The slot 64 of the worm gear 62 is substantially rectangular as shown, but it could be in any appropriate shape. The key 60, a screwdriver, a car or house key or other similarly shaped device may be inserted into the slot 64 to turn the worm gear 62. [00095] Located within the fin plug assembly 24 is the cam 80 which is horizontally placed and has gears or teeth 82. The cam 80 is adapted to fit with the worm gear 62 and rotate and engage the tab 34 of the fin 20, 30. The term "horizontal" used herein refers to the alignment which is longitudinally parallel to the cavity 40 of the fin plug assembly 24. [00096] In the embodiment shown in Figures 3 and 4, turning the worm gear 62 in the clockwise direction is designed to rotate the cam 80 to hold or engage the tab 34 of the fin 20, 30 inserted into the cavity 40, while turning the worm gear 62 in the counter-clockwise direction allows the cam 80 to disengage the tab 34 of the fin 20, 30 from the fin plug assembly 24.

[00097] As illustrated in Figure 4, the fin plug assembly 24 includes a lower part 42 and an upper part 44, which are as a final product sealed together using an ultrasonic welding process or other methods well known in the art. Positioned in the fin plug assembly 24 is the worm gear 62 having a plurality of gears or teeth 68, and the worm gear 62 is vertically placed within the fin plug assembly 24 as shown in Figure 4. The upper part 44 and the lower part 42 of the fin plug assembly 24 form a built in bearing 46 which is adapted to receive the cam 80. The cam 80 is positioned in the bearing 46 between the worm gear 62 and the cavity 40. The cam 80 has a plurality of matching gears or teeth 82 to fit with the gears 68 of the worm gear 62. The cam 80 has a flat or disengaging portion 84 and a bulging or engaging portion 86.

[00098] The cam 80 is generally circular in shape except in the flat portion 84 and in the region where the gears 82 are positioned. The phrase "bulging portion" used herein refers to the generally circular portion of the cam 80 which is aligned with and engages the tab 34 of the fin 20, 30. Alternatively, the bulging portion may be designed to protrude outwardly relative to the truly circular portion of the cam 80. For example, the bulging portion may have an oval shape to make it better fit with the tab 34 of the fin 20, 30. The phrase "bulging portion" used herein therefore means the portion of the cam 80 which is aligned with and engages the tab 34, whether it is substantially circular or alternatively, oval or protruding relative to the truly circular part of the cam. [00099] The cam 80 rotates smoothly on its axle 87 (Figure 7) within the bearing 46 relative to its horizontal axis, and has a stopper 88 on each end of the cam. The bearing 46 has a shape that is substantially similar to that of the cam 80 and is also shaped to receive the stoppers 88 and the axle 87 (Figure 7) located in each end of the cam 80. The fin plug assembly 24 is designed so that an engaging position is achieved by turning the worm gear 62 in a pre-selected direction, i.e., clockwise in the embodiment shown in Figs. 2 and 4, and a disengaging position is achieved by turning the worm gear 62 in the opposite direction, i.e. counter clockwise. Given the relative configuration of the worm gear 62 and the cam 80, clockwise rotation causes the cam 80 to engage the tab 34 of the fin 20, 30 with both a horizontal and vertical force thus pulling the tab 34 down into the cavity 40 and increasing the integrity of the engagement of the fin 20, 30.

[000100] Figure 4 illustrates how the cam 80 is rotated to the engaging position by turning the worm gear 62. In the engaging position, the bulging portion 86 of the cam 80 abuts a side surface 35 of the tab 34 of the fin 20, 30, and creates sufficient friction to prevent the fin from moving or dislodging. When the cam 80 is rotated to the disengaging position, the flat portion 84 is aligned with the side surface of the tab 34, and this allows easy removal/insertion of the fin from/into the cavity 40 and fore/aft adjustment of the position of the fin 20, 30 in the cavity 40. Thus, the present fin plug assembly is designed to receive and secure the fin by controlling the rotation of the cam 80 and aligning the tab 34 of the fin with either the bulging portion 86 or the flat portion 84 of the cam 88. Unlike other known systems, the cam 80 is not designed to extend forward or retract backward to bear against the tab 34 to secure the fin. [000101] The fin plug assembly 24 may be made of a relatively hard plastic or other similar material well known in the art. Preferably, the cam 80 and the worm gear 62 are made of a harder material, i.e. engineering grade plastic, which is less susceptible to distortion, twist, bending, or chipping.

[000102] Because both the cam 80 and the tab 34 are relatively hard, it may be desirable to incorporate softer, malleable rubber materials on certain areas of the tab 34 and/or the bulging portion 86 of the cam 80 to create a more versatile friction fit. By incorporating certain rubber materials, when the cam 80 is rotated to the engaging position, the friction between the bulging portion 86 and the tab 34 may be increased or decreased to provide a more or less secure fit as desired or provide a desired controlled friction. In other words, the malleable rubber material incorporated in the tab 34 and/or the cam 80 allows flexibility and control over the friction desired between the tab 34 and the cam 80, and the force required to cause the fin to be pulled from the fin plug assembly under sudden impacts may also be controlled.

[000103] Figure 5 is a cross sectional view of the fin plug assembly 24 according to another embodiment of the present invention. The cam 80 is rotated to the engaging position in Figure 5 so that the bulging portion 86 is received in a concave portion 36 of the tab 34. The concave portion 36 on the tab 34 has a substantially curved shape and is designed to receive and bear against the bulging portion 86 of the cam 80. Alternatively, as shown in Figure 6, the tab 34 may include a cut out portion 38 which is designed to receive the bulging portion 86 of the cam 80. The embodiment shown in Figure 6 allows greater flexibility in the alignment of the tab 34 and the cam 80.

[000104] In summary, shown in Figures 1 to 6 is a surf fin plug assembly 24 in which turning the worm gear 62 in one direction allows the bulging portion 86 of the cam 80 to align with and engage the tab 34 and secure the fin which is inserted into the cavity 40, while turning the worm gear 62 in the opposite direction allows the flat portion 84 of the cam 80 to align with and disengage the tab 34 for removal or adjustment of the fin. [000105] The fin plug assembly 24 may be used for both the side fins 20 and the rear fin 30. However, the fin plug assembly 24 used for the rear fin 30 may be larger to allow a greater fore-aft movement of the rear fin 30. In addition, as described in more detail below, the fin plug assembly 24 used for the side fins 20 may have a vertical built-in tilt angle while the fin plug assembly 24 for the rear fin 30 preferably does not.

[000106] Figure 7 illustrates more clearly the positioning and relationship between the worm gear 62, the cam 80, and the cavity 40 of the fin plug assembly 24. The cam 80 on each of the two ends has an axle 87 and the stopper 88. The cam 80 also has a plurality of teeth or gears 82 which are designed to fit with the gears of the worm gear 62. By turning the worm gear 62 in one direction, i.e., clockwise, the cam 80 is rotated to engage the bulging portion of cam 80 against the tab 34 of the fin received in the cavity 40. The worm gear 62 has the slot 64 which is substantially rectangular to receive a specially designed key, a screwdriver, a car or house key or other similarly shaped device. The slot 64 of the worm gear 62 may be of any appropriate shape. The fin plug assembly 24 of the present invention also allows a gradual tightening or adjustment of the fin by turning the worm gear 62 only partially or to the point of the desired tension.

[000107] As shown in Figs. 1 and 7, the fin 20, 30 generally has a body portion and a mounting portion. The body portion defines a hydrodynamic foil and is configured to extend generally perpendicularly relative to the lower surface 26 of the surfboard 22. The mounting portion is attached to the body portion and is configured to be received and frictionally held in the cavity 40 of the fin plug assembly 24. The mounting portion preferably includes at least one tab 34 and may incorporate malleable rubber materials to control the friction between the tab 34 and an engaging means, i.e., the cam 80, of the fin plug assembly 24.

[000108] Described now is the installation process of fin plug assemblies using a complete control jig system 90 according to the present invention. Typically, installation of the fin plug assemblies known in the art requires multiple marking and positioning jigs or templates and other tools and accessories, i.e. putty, tape, foam, centre punch, etc. In addition, the conventional installation methods require multiple steps of marking, positioning, removal, and repositioning of the jigs or templates that are often difficult, inaccurate, and time-consuming. The complete control jig system 90 of the present invention allows an easy, quick, and accurate installation of fin plug assemblies.

[000109] Figures 8 and 9 illustrate by way of example a complete control jig system 90 and a method of installing the fin plug assembly using the complete control jig system 90. Figure 8 shows the complete jig system 90 having a pre-cut centre portion 92 which is substantially the same shape as the fin plug assembly to be installed. For the purpose of illustration, the fin plug assembly to be installed is the assembly shown in FIGS 1 to 7 and described above.

[000110] The complete control jig system 90 is used to install the fin plug assembly generally utilising the following process. Before the complete control jig system 90 is placed on the lower surface 26 of the surfboard 22, the surface area where the fin plug assembly is to be installed is generally sanded. Then, marks are made on the surface marking the spots where the front and rear ends of the fin will be after the fin plug assembly is installed, and a line 94 is drawn through the marks. Figures 8 and 9 illustrate the positioning of the complete control jig system 90 for a side fin plug assembly. Once the line 94 is drawn, a peel-off cover 96 on the bottom of the complete control jig system 90 is removed, preferably exposing a self-adhesive surface, and the complete control jig system 90 is positioned along the line 94 as shown in Figures 8-9. The bottom portion of the complete control jig system 90 includes glues, and is positioned on the lower surface 26 of the surfboard 22. When placed on the lower surface 26 of the surfboard 22, the centre portion 92 is removed from the complete control jig system 90.

[000111] Once the complete control jig system 90 is properly placed on the lower surface 26 of the surfboard 22 and the centre portion 92 is removed, a drill with a hole-cutting device, router or other cutting device is used to create a mounting cavity 98 within the surfboard 22. The complete control jig system 90 is designed to guide the drill, router or other cutting device as it is moved around forming the mounting cavity 98. Once the mounting cavity 98 is formed, depth cut outs 97 are removed from the complete control jig system 90 and the surf fin plug assembly 24 as shown in Figure 7 is positioned within the mounting cavity 98The depth cut outs 97 are removed from the complete control jig system 90 so that the outriggers 66 (in Figure 7) of the fin plug assembly 24 are properly aligned and touching the lower surface 26 of the surfboard 22. The temporary supports or outriggers 66 locate the fin plug assembly 24 at the appropriate height relative to the surrounding surface of the surfboard. Preferably, a dummy fin (not shown) may be fitted into the fin plug assembly 24 before the fin plug assembly is positioned into the mounting cavity 98 to insure the proper positioning and installation of the fin plug assembly 24.

[000112] Once the fin plug assembly 24 is properly aligned and positioned within the mounting cavity 98, the space between the fin plug assembly 24 and the mounting cavity 98 within the surfboard 22 is slowly filled with a resin or other hardenable material well known in the art. The complete control jig system 90 is preferably high enough to act as a dam to contain the liquid resin or other hardenable material from overflowing. After the resin or hardenable material has set, the complete control jig system 90, the outriggers 66 and the collar 72 (in Figure 3) of the fin plug assembly 24 are then sanded off so that the top surface 74 of the fin plug assembly 24 is substantially flush with the lower surface 26 of the surfboard 22. The complete control jig system should thus be made of materials suitable for removal by sanding.

[000113] Also, as illustrated by a way of example in Figure 11, the foam material 99 in the body of the surfboard 22, particularly the material extending from the mounting cavity 98 may be further removed to provide additional space 100 for resin or other hardenable material to enter, thereby increasing the stability of the fin plug assembly 24 installed. In one embodiment, a hand tool or other cutting device well known in the art may be used to remove material from a region extending from the base (which is indicated by a dotted line in Figure 11) of the mounting cavity 98 substantially to the skin, typically fibre-glassed, of an upper surface 25 of the surfboard 22. This space 100 is filled with resin or other hardenable material to provide greater structural strength and stability to the fin plug assembly 24 which is installed in the surfboard 22.

[000114] Alternatively, a spiking tool may be used to spike material from regions extending from the side and/or the base of the mounting cavity 98 to create additional space for resin or other hardening material to enter. Such space 102, 104 may extend vertically or at an angle as shown in Figure 11, and when a spiking tool is used, the foam material around the spiked point is also compressed and the compressed foam material 101 provides additional structural support. If needed, the space 102 created by the spiking tool can substantially touch to the skin, typically the fibre-glassed, of the upper surface 25 of the surfboard 22.

[000115] The complete control jig system 90 of the present invention also allows an easy adjustment of the tilt angle for the fins. As discussed above, it may be desirable for the fins to have a vertical tilt angle. Typically, the side fins are vertically tilted toward the outwardly direction at about 4°. The term "outwardly" used herein refers to the direction opposite to the centre portion of the surfboard 22. The rear fin 30 usually does not require a tilt angle. To accommodate the desired tilt angle for the side fins, the fin plug assembly 24 for the side fins 20 according to the present invention has a built-in tilt angle, typically 3°-5°, and preferably 4°. [000116] If it is desirable to have a tilt angle greater than 3°-5°, a small amount of putty may be pushed into the depth cut outs 97 of the complete control jig system 90. The fin plug assembly 80 can now be tilted using the putty to control the depth of the outriggers 66.

[000117] The complete control jig system 90 controls and guides the installation of fin plug assemblies 24. The installation process utilising the complete control jig assembly 90 of the present invention is easy, accurate and less time consuming, and provides a significant improvement compared to other conventional systems. [000118] Figure 10 is an exemplary view illustrating how multiple units of the fin plug assembly 24 according to the present invention may be used to fix the fin 30 with multiple tabs 34. Shown in Figure 10 are two fin plug assemblies 24 embedded within the surfboard 22. The arrangement shown in Figure 10 is particularly useful for securing larger rear fins which require greater anchoring. The rear fin 30 in Figure 10 has two tabs 34, and each tab 34 may be inserted and secured into a separate fin plug assembly 24. Alternatively, each fin plug assembly 24 may also receive one and more tabs 34. [000119] Figure 12 illustrates a cross sectional view of the fin plug assembly 24 where the tab 34 has an undercut 100 that cuts into a first side 102 of the tab 34 at a predetermined position 104 and terminates in a slopping angle at the base 106 of the tab 34. The undercut 100 may form an angle θl with the vertical line 108. The angle 01 may vary depending on the contour of the bulging portion 86 of the cam 80. The angle θl may be set so that as the cam 80 rotates in a counter-clockwise direction, the bulging portion 86 engages with the undercut 100 to pull down the tab 34 into the cavity 40 until the tab is securely held in place. The angle θl may be between about 5° and about 45°. One of the advantages of having an undercut 100 to engage with the cam 80 is that the bulging portion 86 may engage with any portion of the undercut 100 between the predetermined position 104 and the base 106 to ensure that the tab securely engages within the cavity 40. [000120] Figure 13 illustrates the tab 34 having an undercut 110 that terminates above the base 106. This way the undercut angle Θ2 may be greater than θl as shown in Figure 12 without having to cut deep into the first side wall 102 along the predetermined position 104. Having the undercut at a steeper angle may allow the bulging portion to engage better with the undercut.

[000121] Figurel4 illustrates a side view of a fin with a tab 34 extending from the end surface 32. As further illustrated in Figure 15, the tab 34 may have the first side 102 and a second side 112, where the first side 102 engages with the cam 80 and the second side 112 engages with a side wall 114 formed within the cavity 40 as illustrated in Figure 16. The second side 112 and the sidewall 114 may have corrugation 111 to associate with each other so that when the worm gear 62 is activated the corrugated second side 112 may flush against the corrugated sidewall 114 within the cavity as illustrated in Figure 17. With the second side 112 and the side wall 114 being both corrugated, the tab 34 may be substantially locked in place from back forth movement along the longitudinal axis of the tab, and substantially prevented from being pulled out of the cavity when the side fin or the rear of the fin accidentally hits a rock or an impending object during surfing. Alternatively, either the sidewall 114 or the second side 112 may be corrugated, but not both sides.

[000122] Figures 18-20 illustrated that certain portions of the second side may be corrugated rather than being substantially corrugated along the entire second side 112. For example, Figure 18 illustrated that the corrugation may be formed on the forward sides 116 of the tab 34. Figure 19 illustrates that the corrugation may be formed on the rear side 118 of the tab 34. Figure 20 illustrates that corrugation may be formed both on the forward side 116 and the rear side 118 but not on the centre portion of the tab 34. Figure 21 illustrates that the corrugation may run along the longitudinal access 120 of the fin 34 rather than vertically as illustrated in Figure 14. In such a case, the sidewall 114 within the cavity 40 may also be corrugated to match the corrugation that is formed along the longitude and the access of the tab 34. The corrugation may have a variety of shapes such as a sinusoidal configuration as illustrated in Figure 15. Alternatively, corrugation may have triangle and rectangle shapes. For example, as further illustrated in Figure 22, the corrugation between the side wall 114 and the second side 112 may engage so that the fin does not get removed from the cavity due to any bending force on the fin caused by the fin hitting a rock for example.

[000123] Figure 23 illustrates another fin plug assembly 200 that includes a worm gear 62 position adjacent to the cavity 40 formed within the fin plug assembly 200. The worm gear 62 may have teeth that protrudes into the cavity 40 that is adapted to engage with thread 206 formed on the first side 102 of the tab 34. In this embodiment, as the worm gear 62 is actuated by rotation for example, the teeth 68 engages with the thread 206 to secure the tab 34 within the cavity 40 of the assembly 200. With the fin plug assembly 24, the need for the cam may be eliminated.

[000124] Figure 24 illustrates a fin plug assembly 24 including a worm gear 302 that has teeth 304 adapted to associate with an undercut 306 form on the first side 102 of the tab 34. Teeth 304 may have a pitch angle that increases as the worm gear 302 is rotated so that as the worm gear is rotated in a certain direction, the thread 304 pushes down on the undercut 306 to secure the tab 34 within the cavity 40. As illustrated in Figure 24, to insert the tab 34 into the cavity 40, the worm gear 302 may be positioned so that the teeth 304 has a pitch angle αl facing the undercut 306. And as the worm gear 302 is rotated to engage the tab 34 within the cavity 40, the pitch angel increases until the pitch angle α2 engages with the undercut 306. The rotation action of the worm gear 302 may draw the tab 34 into the cavity because of the downward force of the teeth 304 on the undercut 306 as the pitch angle increases. When the worm gear 302 is rotated so that it is fully engaged, the pitch angle α2 may be substantially equal to the angle Θ3 formed on the undercut 306 so that the surface area of the teeth 304 substantially engage the surface area of the undercut 306.

[000125] It will be understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text. All of these different combinations constitute various alternative aspects of the invention.

[000126] Having thus described different embodiments of the invention, other variations and embodiments that do not depart from the spirit of the invention will become readily apparent to those skilled in the art. The scope of the present invention is thus not limited to any one particular embodiment, but is instead set forth in the appended claims and the legal equivalents thereof.

Claims

CLAIMS:

1. A removable fin mounting assembly comprising: a fin; a fin plug assembly defining a cavity adapted to receive a portion of said fin; a cam having gears, said cam positioned within said fin plug assembly adjacent to said cavity; and a worm gear positioned within said fin plug assembly and adapted to engage with said gears of said cam, wherein turning said worm gear causes said cam to rotate and secure said portion of said fin received in said cavity.

2. A removable fin mounting assembly as claimed in claim 1, said fin further comprising a tab wherein said tab is received in said cavity.

3. A removable fin mounting assembly as claimed in claim 2, wherein the length of said cavity is greater than the length of said tab allowing a fore-aft adjustment of said fin within said cavity.

4. A removable fin mounting assembly as claimed in any one of claims 1 to 3, wherein said cam further comprising a flat portion and a bulging portion.

5. A fin mounting assembly as claimed in any one of claims 1 to 4, wherein turning said worm gear in one direction rotates said cam to an engaging position while turning said worm gear in an opposite direction rotates said cam to a disengaging position.

6. A fin mounting assembly as claimed any one of claims 4 or 5 when dependent on claim 4, wherein said bulging portion of said cam is aligned with said fin in said engaging position while said flat portion of said cam is aligned with said fin in said disengaging position.

7. A fin mounting assembly as claimed in any one of claims 4, or 5 and 6 when dependent upon claim 4, wherein said bulging portion includes a rubber material.

8. A fin mounting assembly as claimed in any one of claims 1 to 7, said worm gear further comprising an opening adapted to receive a means for turning said worm gear.

9. A fin mounting assembly as claimed in claim 8, wherein said opening is substantially rectangular and said means for turning said worm gear includes a plastic key, a screwdriver, and a car or house key.

10. A fin mounting assembly as claimed in any one of claims 1 to 9, wherein said fin includes a rubber material.

11. A fin mounting assembly as claimed in any one of claims 1 to 10, wherein said fin has a side surface, said side surface being adjacent to said cam when said fin is received in said cavity.

12. A fin mounting assembly as claimed in any one of claims 1 to 11 , wherein said fin has a side surface having a concave portion, said concave portion being adjacent to said cam when said fin is received in said cavity.

13. A fin mounting assembly as claimed in any one of claims 1 to 11 , wherein said fin has a side surface having a cut out portion, said cut out portion being adjacent to said cam when said fin is received in said cavity.

14. A fin mounting assembly as claimed in any one of claims 1 to 13, further comprising an upper part and a lower part, wherein said upper part includes a plurality of supporting arms.

15. A fin mounting assembly as claimed in any one of claims 1 to 14, wherein said fin plug assembly is adapted to be embedded in a body of a surfcraft.

16. A fin mounting assembly as claimed in any one of claims 1 to 15 wherein said worm gear is positioned vertically.

17. A fin mounting assembly as claimed in any one of claims 1 to 16, wherein said fin is adapted to move fore-aft within said cavity.

18. A fin mounting assembly as claimed in any one of claims 1 to 17, wherein said cavity has built-in tilt angle.

19. A fin mounting assembly as claimed in claim 18, wherein said built-in tilt angle is 3° to5°.

20. A fin comprising: a body portion, said body portion configured to extend generally perpendicularly relative to a lower surface of a surfcraft; and a mounting portion attached to said body portion, said mounting portion configured to be received and frictionally held in a cavity defined by a fin plug assembly embedded in said surfcraft.

21. A fin as claimed in claim 20, wherein said mounting portion includes a soft, malleable material.

22. A fin as claimed in claim 21, wherein said soft, malleable material is rubber.

23. A fin as claimed in any one of claims 20 to 22, wherein said mounting portion includes at least one tab.

24. A fin as claimed in claim 23, wherein said tab extends away from said fin.

25. A fin as claimed in any one of claims 23 or 24, wherein said fin has a first side with a sloping undercut adapted to engage with a fin plug assembly.

26. A fin as claimed in claim 24, where the tab has a second side, where at least a portion of the second side is corrugated and adapted to associate with a sidewall formed within a cavity.

27. A fin as claimed in claim 26 , where the portion of the second side of the tab that is corrugated is on a front portion.

28. A fin as claimed in any one of claims 26 to 27, where the portion of the second side of the tab that is corrugated is on a back portion.

29. A fin as claimed in any one of claims 26 to 28, where the portion of the second side of the tab that is corrugated is on a middle portion.

30. A fin as claimed in any one of claims 26 to 29, where the portion of the second side of the tab that is corrugated is substantially the second side.

31. A fin as claimed in any one of claims 26 to 30, where the second side is corrugated to form a sine wave.

32. A fin according to any one of claims 26 to 31, where the second side is corrugated to form a saw-tooth configuration.

33. A combination of a fin mounting assembly as claimed in any one of claims 1 to 14, with a fin as claimed in any one of claims 20 to 32.

34. A method of installing a fin plug assembly in a surfcraft comprising: positioning a complete control jig system on a lower surface of said surfcraft where said fin plug assembly is to be embedded; removing a centre portion of said complete control jig system; creating a mounting cavity within said surfcraft, said mounting cavity having a substantially same shape and size as said centre portion; positioning said fin plug assembly within said mounting cavity, wherein said fin plug assembly has a plurality of supporting arms; removing depth cut outs of said complete control jig system; aligning and positioning said supporting arms of said fin plug assembly into said depth cut outs; filling said mounting cavity with a resin; and sanding off said complete control jig system, a top surface and said supporting arms of said fin plug assembly.

35. A method as claimed in claim 34, further comprising fitting a dummy fin into said fin plug assembly.

36. A method as claimed in any one of claims 34 or 35, further comprising placing a variable amount of putty into said depth cut outs and adjusting a vertical tilt angle of said fin plug assembly.

37. A method as claimed in any one of claims 34 to 36, wherein said centre portion and said depth cut outs are pre-cut.

38. A method as claimed in any one of claims 34 to 37, wherein said centre portion is in a substantially similar shape as an outline of said fin plug assembly.

39. A method as claimed in any one of claims 34 to 38, further comprising removing materials extending from said mounting cavity and creating a space for said resin to fill.

40. A method of claim 39, wherein said space extends substantially to a skin of an upper surface of said surfcraft.

41. A system for releasably securing a tab of a fin, comprising: a fin plug assembly having a cavity adapted to receive a tab extending from a fin; a worm gear having teeth adapted to rotate within the fin plug assembly; a cam between the worm gear and the cavity, where the cam is adapted to engage with the teeth of the worm gear such that rotation of the worm gear causes the cam to engage with the tab of the fin within the cavity.

42. A system as claimed in claim 41, where the tab has a first side with a sloping undercut adapted to engage with the cam, where rotation of the worm gear causes the cam to engage with the sloping undercut to secure the tab within the cavity of the fin plug assembly.

43. A system as claimed in claim 42, where counter rotation of the worm gear causes the cam to release the sloping undercut of the tab within the cavity.

44. A system as claimed in any one of claims 42 or 43, where the sloping undercut extends to a base of the tab.

45. A system as claimed in any one of claims 42 to 44, where the sloping undercut terminates above a base of the tab.

46. A system as claimed in any one of claims 41 to 45, where the tab has a second side, where at least a portion of the second side is corrugated, where the cavity has a side wall adapted to associate with the second side of the tab that is corrugated.

47. A system as claimed in claim 46, where the portion of the second side of the tab this is corrugated is on a front portion.

48. A system as claimed in any one of claims 46 or 47, where the portion of the second side of the tab is corrugated on a back portion

49. A system as claimed in any one of claims 46 to 48, where the portion of the second side of the tab is corrugated on a middle portion.

50. A system as claimed in any one of claims 46 to 49, where the portion of the second side of the tab is corrugated on substantially the second side.

51. The system as claimed in any one of claims 46 to 50, where the second side is corrugated to form a sine wave.

52. A system as claimed in any one of claims 46 to 51 , where the second side is corrugated to form a sawtooth configuration.

53. A system for engaging a fin to a surfcraft, comprising: a worm gear having teeth adapted to be actuated within a fin plug assembly that has a cavity adapted to receive a tab extending from a fin, where actuation of the worm gear causes the tab to be secured within the cavity.

54. A system as claimed in claim 53, further including a cam between the tab and the worm gear, where the cam have teeth to engage with the teeth of the worm gear.

55. A system for engaging a fin to a surfcraft, comprising: a worm gear having teeth adapted to actuate within a fin plug assembly; and a tab having a first side adapted to engage with the teeth of the worm gear, where rotation of the worm gear causes the tab to secure within the cavity.

56. A system as claimed in claim 55 where the first side of the tab has a thread that engages with the teeth of the worm gear that causes the tab to secure within the cavity with the rotation of the worm gear.

57. A system as claimed in any one of claims 55 or 56, where the first side of the tab has an undercut that engages with the teeth of the worm gear that causes the tab to secure within the cavity with the rotation of the worm gear.

58. A system as claimed in claim 57, where the teeth has a pitch angle that increases with rotation of the worm gear to engage the undercut on the first side of the tab to secure the tab within the cavity with the rotation of the worm gear.

59. A system as claimed in any one of claims 55 to 58, where the longitudinal axis of the worm gear is substantially parallel with the longitudinal axis of the tab.

60. A system as claimed in any one of claims 55 to 59, where a counter-rotation of the worm gear causes the tab to be released from the cavity.

61. A system for engaging a fin for a surfcraft, comprising: a worm gear having teeth adapted to actuate in a fin plug assembly that has a cavity adapted to receive a tab extending from a fin; and a cam between the worm gear and the cavity, where the cam is adapted so that actuation of the worm gear causes the cam to engage with the tab from the fin.

62. A system as claimed in claim 61, where the cam has teeth to engage with the teeth of the worm gear.

63. A method for engaging a fin to a surfcraft, comprising: forming a tab protruding from a fin for a surfcraft; inserting the tab into a cavity formed within a plug assembly formed within a surfcraft; and engaging a side of the tab within the plug assembly to secure the fin to the surfcraft.

64. A method as claimed in claim 63, further including: undercutting the side of the tab to engage with a cam within the plug assembly; and actuating a worm gear that causes the cam to engage with the undercutting.

65. A method as claimed in any one of claims 63 or 64, further including: threading the side of the tab; actuating the worm gear that has teeth; and engaging the teeth of the worm gear to the threading to hold the tab within the cavity.

66. A method as claimed in any one of claims 63 to65, further including: undercutting the side of the tab; increasing a pitch angle of a teeth on a worm gear; rotating the worm gear to engaging the teeth with the undercutting on the side of tab to engage the tab within the plug assembly.

67. A surfcraft having a removable fin mounting assembly as claimed in any one of claims 1 to 19.

68. A surfcraft having a fin as claimed in any one of claims 20 to 32.

69. A surfcraft having a combination of a fin mounting assembly and fin as claimed in claim 33.

70. A surfcraft having a fin plug assembly installed by the method of any one of claims 34 to 40.

71. A surfcraft having system for engaging a fin as claimed in any one of claims 41 to 62.

72. A surfcraft having a fin which is engaged by the method of any one of claims 63 to 66.

73. A surfcraft as claimed in any one of claims 67 to 72, wherein said surfcraft is a surfboard.