WO2005085058A1

WO2005085058A1 - Fin plug

Info

Publication number: WO2005085058A1
Application number: PCT/AU2005/000319
Authority: WO
Inventors: Anthony Rodier
Original assignee: Surfing Hardware International Holdings Pty Ltd
Priority date: 2004-03-05
Filing date: 2005-03-07
Publication date: 2005-09-15

Abstract

A fin plug (10), adapted for installment within a surfcraft comprising a top surface (11) having a single cavity (12) for receiving a fin tab, engagement means for removably securing the fin tab within the cavity (12) and a surrounding side wall (14) having a plurality of rib portions (15) extending substantially longitudinally from about a base portion (16) of the fin plug (10) to near the top surface (11) of the fin plug (11).

Description

Fin Plug

Technical Field This invention relates to fin plugs designed to be rigidly affixed to a surfcraft, such as a surfboard. The relevant fin plug is also generally adapted to receive a tab of a surfboard fin for removably attaching the surfboard fin to the surfcraft.

Background to the Invention In recent years removable fins have largely replaced fixed fins in surfboards and other surfcraft. Removable fins are generally attached to the surfcraft by means of one or more tabs extending from the base of the fin which fit within corresponding slots in a fin plug within the surfcraft. The fin plugs which are in common use at the present time consist of generally cylindrical bodies having a rectangular shaped cavity for receiving a fin tab. The fin plugs also generally include screw means for releaseably securing the fin tab within the rectangular cavity. Such fin plugs are generally described in Australian patent application no. 34088/93 in the name of Fin Control Systems Pty Ltd. Such fin plugs are secured within the surfcraft in the manner generally described in AU 34088/93, which is incorporated herein by reference. One of the problems with the fin plugs made according to the disclosure in AU 34088/93 is that the circular side wall does not always form a perfectly rigid bond with the hardened resin which surrounds it and holds it in place in the surfcraft. US Patent No. 6,139,383, in the name of Pat-Tech Pty Ltd, discloses a similar arrangement, including a fin with a fin tab and a fin plug for removably attaching the fin to a surfcraft. The fin plug of US 6,139,383 comprises two plug sockets separate by a connecting bridge. US 6,139,383 discloses a number of embodiments of the relevant fin plug, all of which contain two plug sockets joined by a connecting bridge. The differences between the embodiments relate primarily to the cross-sectional shape and the structure of the outer walls of the plug. For example, in one embodiment (shown in figure 2 of 6,139,383) each plug socket has a series of bites located circumferentially around the outer surface thereof. In another embodiment, the outer surface of the fin plug, including each plug socket and the connecting wall, includes a series of substantially identical, sequential ridges and channels (see figures 8 and 9 of US 6,139,383). One of the problems with the fin plug of US 6,139,383 is that the distance between the plug sockets is fixed. This means that the fin plug will only be adapted for use with fins that have fin tabs separated by the same distances as the distance between the cavities in the corresponding fin sockets. The limits the range of fins which can be used with these fin plugs. Another problem with the fin plugs described above is that different portions of the fin plugs have substantially different thicknesses. Accordingly, when the fin plugs are made of plastic using injection moulding techniques (which is commonly how they are formed), different portions of the plug will cool at different rates and over different time periods. This can result in warping and structural inconsistencies within the body. With the above problems in mind, the present invention is directed towards a fin plug which can be more securely affixed to a surf craft and which is less prone to warping and/or air bubble retention during the formation process.

Summary of Invention In a first aspect, the present invention provides a fin plug, adapted for instalment within a surfcraft, comprising: a top surface having a single cavity for receiving a fin tab; engagement means for removably securing the fin tab within the cavity; a surrounding side wall having a plurality of rib portions extending substantially longitudinally from about a base portion of the fin plug to near the top surface of the fin plug. Preferably, the longitudinally extending rib portions substantially inhibit the possibility of any clockwise or counter-clockwise rotation of the fin plug when affixed within the surfcraft. More preferably, at least one of the rib portions is defined by channels extending along each side of said rib portion. Typically, each rib portion is defined by such channels extending along each side thereof. Preferably, the surrounding side wall has between 2 to about 8 rib portions.

More preferably, the surrounding side wall has 6 rib portions. In this embodiment, the surrounding side wall may have 3 rib portions located on each of two opposing sides of the side wall. Preferably the surrounding side wall is substantially circular in profile. In this embodiment, an external face of each rib portion may form part of the side wall, in which case the channels located alongside the rib portions are recessed from the side wall. Preferably, a recess is formed in an external face of at least one of the rib portions. Preferably, 2 or more of the rib portions include at least one such recess. A particular rib portion may include 2 or more of said recesses. Preferably, at least one of the rib portions comprises at least one stub extending from a side face of said rib portion. Preferably, more than one rib portion comprises at least one stub. Such rib portions preferably include 2 stubs extending from said side face. The abovementioned recesses and stubs are adapted to inhibit longitudinal movement of the fin plug when located within a surfcraft. Preferably, the fin plug is of generally uniform material thickness throughout. This effectively means that most portions of the fin plug (eg including the side wall, the ribs and the stubs) have a material thickness which is generally similar or comparable. A benefit of this is that, when a fin plug according to this invention is formed from injection moulding (or similar) techniques, involving heated (liquid) polycarbonate or some other plastic material, the various portions will cool down at substantially similar rates. This in turn reduces the likelihood of warping occurring and it tends to result in a product having improved structural consistency and/or integrity. Preferably, the side wall of the fin plug further comprises a recessed bite extending circumferentially about at least a portion of said side wall. This is adapted further to inhibit any longitudinal movement of the fin plug when affixed within a surfcraft. Preferably, the fin plug also includes a plurality of laterally extending supporting arms for aligning and positioning the fin plug in a hole on the surface of a surfcraft during the installation process. The supporting arms are located peripherally on the surrounding side wall near the top surface of the fin plug. Preferably, the engagement means is in the form of a grub screw located within a screw hole. The grub screw and screw hole are adapted so that, upon rotation of said grub screw, it may selectively be moved into and out of the cavity into which a fin tab is positioned. This enables the fin tab to be removably secured within the cavity. Preferably, the fin plug is formed of polycarbonate. A particularly preferred polycarbonate is GE Lexan™ 123 polycarbonate. In a second aspect, the present invention provides a surfcraft which includes therein a fin plug according to the first aspect of this invention. Other aspects, advantages and modifications within the scope of this invention will be apparent to those skilled in the art to which this invention relates. Throughout this specification, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps. Any discussion of documents, acts materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed in Australia before the priority date of each claim of this application. In order that the present invention may be more clearly understood, preferred forms will be described with reference to the following drawings and examples.

Brief Description of the Drawings Figure 1 (a) is a top view of one embodiment of a fin plug in accordance with the present invention; (b) is a right side view of one embodiment of a fin plug in accordance with the present invention; (c) is a bottom view of one embodiment of a fin plug in accordance with the present invention; (d) is a front view of one embodiment of a fin plug in accordance with the present invention; (e) is a perspective view of one embodiment of a fin plug in accordance with the present invention. Figure 2(a) is a left perspective view of another embodiment of a fin plug in accordance with the present invention; (b) is a front view of another embodiment of a fin plug in accordance with the present invention; (c) is a right perspective view of another embodiment of a fin plug in accordance with the present invention; (d) is a bottom view of another embodiment of a fin plug in accordance with the present invention; (e) is a left side view of another embodiment of a fin plug in accordance with the present invention; (f) is a top view of another embodiment of a fin plug in accordance with the present invention; (g) is a right side view of another embodiment of a fin plug in accordance with the present invention; (h) is a front view of another embodiment of a fin plug in accordance with the present invention.

Detailed Description of a Preferred Embodiment(s) Referring to the drawings, the fin plug 10 comprises a top surface 1 1 having a cavity 12 for receiving a fin tab (not shown) and screw hole 13 for receiving a grub screw (not shown). The grub screw is adapted to extend into or out of the cavity 12 by rotation of said screw. Accordingly, the grub screw is thereby adapted to enable the fin tab to be selectively removably secured within the cavity 12. The fin plug also comprises a surrounding side wall 14 which has a plurality of rib portions 15 extending substantially longitudinally from about a base portion 16 of the fin plug to near the top surface 11 of the fin plug. As shown in Figures 1 (a) to 1 (e) and 2(a) to 2(h), the surrounding side wall 14 of the fin plug 10 is substantially circular in profile. The plurality of rib portions 15 are located circumferentially about the fin plug 10. In the embodiment of the invention shown in the drawings, there are 6 rib portions 15. 3 of these are located on one side of the fin plug and the other 3 are located on an opposite side. Alongside each of the ribs 15 is a channel 17. A recess 18 extending from an outer surface of a rib portion 15 is located in at least one of the rib portions. Preferably, when the fin plug is being installed within a surf craft, this arrangement of ribs, channels and recesses enables hardening resin, which is placed around the fin plug, to flow into the channels, recesses etc. This results in a fin plug which is able to be more rigidly secured within the surf craft. Figures 2(a) to 2(h) illustrate a preferred embodiment of the fin plug 10 in which the fin plug incorporates a relatively complex arrangement of ribs, channels and recesses adapted to more securely affix the fin plug within a surfcraft when surrounded by hardened resin. In this further embodiment, the fin plug 10 again incorporates a plurality (eg 6) rib portions, having an equal number (eg 3) on opposite sides of the fin plug. Adjacent each rib portion 15 is a corresponding channel 17. The central rib portion 19 on each side has one or two recesses 18 formed (or carved) therein. Stubs 20 extend from a side face of each outer rib portion 21. These are intended further to inhibit longitudinal movement of the fin plug when installed in the surf craft. A particularly desirable feature of the fin plug according to the present invention is that various different portions of the fin plug have thicknesses which are very similar. This is particularly so in respect of the further preferred embodiment of the invention shown in Figures 2(a) to 2(h). A consequence of a plug having generally uniform thickness is that, during formation of the fin plug by injection moulding techniques, the plastic material will cool at generally the same rate over substantially the same time period. Consequently, the various portions of the fin plug are less likely to suffer warping and the product as a whole tends to have more consistent structural integrity. To install the fin plugs into a surfcraft, holes are bored into the underside of the surfcraft (not shown) in predetermined positions relative to each other to create a mounting cavity within the surfcraft. Each mounting cavity is adapted to receive a fin plug. Resin is placed into the bottom of each mounting cavity and the fin plug 10 placed into the cavity. The supporting arms 22 rest on the surface of the surfcraft so as to align and position the fin plug within the mounting cavity. Further resin is then applied into the hole and allowed to move in and around the complex arrangement of ribs, channels and recesses. Once the resin has hardened sufficiently, the surfcraft is then sanded, removing the supporting arms 22 and the top section of the side wall protruding above the surface of the surfcraft. Surfcraft fins may then be fitted into the fin plugs and secured into the cavity 12 by the grub screws in the screw holes. From the foregoing, it is evident that the present invention provides a fin plug which is adapted to be more securely embedded within a surfcraft. Also, the fin plug of this invention is less prone to warping during the plug manufacturing process. Also, the fin plug according to the present invention tends to have improved structural uniformity and/or integrity. The arrangement whereby the fin plug comprises various channels and cavities allows less material to be used in the formation of the fin plugs, and results in a product which is advantageously lighter and which is likely to be cheaper to manufacture. It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiment are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

The claims defining the invention are as follows:

1. A fin plug, adapted for instalment within a surfcraft, comprising: a top surface having a single cavity for receiving a fin tab; engagement means for removably securing the fin tab within the cavity; • a surrounding side wall having a plurality of rib portions extending substantially longitudinally from about a base portion of the fin plug to near the top surface of the fin plug.

2. A fin plug according to claim 1 , wherein at least one of the rib portions is defined by channels extending along each side of said rib portion.

3. A fin plug according to claim 2, wherein each rib portion is defined by said channels extending along each side of said rib portions.

4. A fin plug according to any one of the preceding claims, wherein the surrounding side wall has between 2 and about 8 rib portions.

5. A fin plug according to claim 4, wherein the surrounding side wall has 6 rib portions.

6. A fin plug according to claim 5, wherein 3 of said rib portions are located on one side of said fin plug and the other 3 said rib portions are located on an opposite side of said fin plug.

7. A fin plug according to any one of the preceding claims, wherein at least one of the rib portions comprises at least one stub extending from a side face of said rib portion.

8. A fin plug according to claim 7 wherein a plurality of the rib portions comprise at least one of said stubs.

9. A fin plug according to any one of the preceding claims, wherein at least one of the rib portions has at least one recess formed in an external face thereof.

10. A fin plug according to claim 11 wherein said at least one rib portion has 2 or more said recesses.

11. A fin plug according to any one of the preceding claims, wherein the fin plug is of generally uniform material thickness throughout.

12. A fin plug according to claim 9, wherein a majority of individual portions of said fin plug have a material thickness which is substantially the same.

13. A fin plug according to any one of the preceding claims, wherein the side wall further comprises a recessed bite extending circumferentially about at least a portion of said side wall.

14. A fin plug according to any of the preceding claims, wherein the surrounding side wall has a generally circular profile.

15. A fin plug according to any one of the preceding claims, wherein the engagement means is a grub screw located within a screw hole within said fin plug, said grub screw being adapted selectively to extend into and out of the cavity in said top surface.

16. A fin plug according to any one of the preceding claims, wherein the fin plug further comprises a plurality of laterally extending supporting arms for aligning and positioning the fin plug in a hole in a surface of a surfcraft during installation.

17. A fin plug according to claim 16, wherein the supporting arms are positioned peripherally on the surrounding side wall near the top surface of the fin plug.

18. A fin plug according to any one of the preceding claims, wherein the fin plug is formed of polycarbonate.

19. A fin plug according to claim 18, wherein the polycarbonate is GE Lexan™ 123 polycarbonate.

20. A surfcraft having formed therein, a fin plug according to any one of the preceding claims.

21. A fin plug, adapted for instalment within a surfcraft, said fin plug being substantially as hereinbefore described with reference to any one of the drawings.