Adjustable fin system

Abstract

An adjustable fin for use on a surfboard, the adjustable fin comprising: a base which comprises a mounting means for mounting the adjustable fin to a surfboard, and a member extending in a direction contrary to the mounting means. The adjustable fin further comprises a fin section comprising two outer fin surfaces which meet at a leading edge and a trailing edge; an underside surface comprising an opening to an internal cavity, the internal cavity configured to house the member and enable slidable movement of the member in a direction towards the leading edge or the trailing edge; and a locking means that is manipulate and which projects into the internal cavity, wherein the locking means can releasably couple to the member at one of two or more locking positions thereby preventing slidable movement of the member. The fin section can be adjusted relative to the base by manipulating the locking means to uncouple the locking means from the member at a first locking position, slidably move the member through the internal cavity, and releasably couple the locking means to the member at a second locking position.

Claims

1. A dual fin for use on a surfboard, the dual fin comprising: a fin section comprising two outer fin surfaces which meet at a leading edge and a trailing edge, wherein the fin section is elongated in a first direction from the leading edge to the trailing edge; a second fin section comprising two outer fin surfaces which meet at a leading edge and a trailing edge, wherein the second fin section is elongated in a second direction from the leading edge to the trailing edge, and a base, comprising a mount for attaching the dual fin to a surfboard wherein an outer fin surface of the fin section is positioned adjacent to and facing an outer fin surface of the second fin section such that the first direction and second direction are substantially parallel.

2. A dual fin according to claim 1, wherein the second fin section is attached to the fin section by an attachment.

3. A dual fin according to claim 2, wherein the attachment comprises a rib.

4. A dual fin according to claim 2, wherein the attachment preserves a minimum distance between the fin section and the second fin section of between approximately 0.25 mm and 1.5 mm.

5. The dual fin according to claim 1, wherein the fin section comprises a flat foil having a flat outer fin surface, and a curved outer fin surface.

6. The dual fin according to claim 5, wherein the second fin section comprises a flat foil having a flat outer fin surface and a curved outer fin surface, wherein the flat outer fin surface of the second fin section and the flat outer fin surface of the fin section both face a same direction.

7. The dual fin according to claim 6, wherein the flat outer fin surface of the fin section faces the curved outer fin surface of the second fin section.

8. The dual fin according to claim 1, wherein the second fin section is positioned parallel to the fin section and offset such that the leading edge of the second fin section is not aligned with the leading edge of the fin section.

9. The dual fin according to claim 1, comprising a passage through the second fin section through which water can pass, wherein the passage comprises an opening on the two outer fin surfaces of the second fin section through which water can enter and/or exit.

10. The dual fin according to claim 9, comprising a passage through the second fin section through which water can pass, wherein: the passage comprises an opening on the flat outer fin surface, and an opening on the curved outer fin surface, and the opening on the curved outer fin surface is located between the trailing edge of the second fin section and the minimum distance between the fin section and the second fin section; the opening of the passage on the flat outer fin surface is located closer to the leading edge of the second fin section than the opening of the passage on the curved outer fin surface of the second fin section; and water can enter the opening on the flat outer fin surface, pass through the passage, and exit through the opening on the curved outer fin surface.

11. The dual fin according to claim 10, wherein water can enter the opening of the passage on the flat outer fin surface, pass through the passage, and exit through the opening of the passage on the curved outer fin surface.

12. The dual fin according to claim 1, wherein the mount comprises a mounting block capable of attaching to fin plug and fin box systems.

13. The dual fin according to claim 1, wherein the mount comprises a base attachment surface and an adhesive for mounting the dual fin to an outer surface of a surfboard.

14. The dual fin according to claim 1, comprising an extended base, wherein when the dual fin is mounted on a surfboard, the extended base forms a gap between the outer surface of the surfboard and the fin section and second fin section.

15. The dual fin according to claim 14, wherein the gap is between approximately 10 mm and 20 mm long.

16. The dual fin according to claim 1, for mounting to any one of the boards in the group comprising: surfboard, shortboard, kneeboard, longboard, minimal, soft board, kiteboard, wind surfer, stand up paddleboard, wakeboard, rescue board, bodyboard, or another board used in surface water sports or activities.

17. A process comprising the step of mounting a dual fin according to claim 1, to any one of the boards in the group comprising: a surfboard, a shortboard, a kneeboard, a longboard, a minimal, soft board, a kiteboard, a wind surfer, a stand up paddleboard, a wakeboard, a rescue board, a bodyboard, or another board used in surface water sports or activities.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1. are illustrations showing oblique views of an exploded (A) and assembled (B) example of the first embodiment of the adjustable fin of the invention. Mount comprises mounting blocks which attach to FCS fin plugs.

(2) FIG. 2. are illustrations showing a top view (A), oblique view (B), side view (C) and front view (D) and the internal mechanism of an example of the first embodiment of the adjustable fin of the invention. Mount comprises mounting blocks which attach to FCS fin plugs.

(3) FIG. 3. are illustrations showing oblique views of an exploded example of the first embodiment of the adjustable fin of the invention (A) and when mounted to a surfboard (B). Mount comprises a base attachment surface and an adhesive.

(4) FIG. 4. are illustrations showing a side view (A), the opposing side view (B), front view (C) and top view (D) of an example of the second embodiment of the adjustable dual fin of the invention. Mount comprises mounting blocks which attach to FCS fin plugs.

(5) FIG. 5. are illustrations showing an oblique view (A), blueprint of the oblique view (B), side view (C), blueprint of the side view (D), and an exploded oblique view (E) of an example of the second embodiment of the adjustable dual fin of the invention. Mount comprises mounting blocks which attach to FCS fin plugs.

(6) FIG. 6. are illustrations showing oblique view (A), oblique exploded view (B), and (clockwise from top left) top, side, oblique and front view (C) of adjustable fins of the invention mounted by a base attachment surface and an adhesive to a surfboard, with adjustable dual fins of an example of the second embodiment of the invention mounted as side fins, and an adjustable fin of an example of the first embodiment of the invention mounted as the centre fin.

DESCRIPTION OF PREFERRED EMBODIMENTS

(7) Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. It is to be understood that the invention includes all such variations and modifications. The invention also includes all of the steps, features, compositions and compounds referred to or indicated in the specification, individually or collectively and any and all combinations or any two or more of the steps or features.

(8) The present invention is not to be limited in scope by the specific examples described herein, which are intended for the purpose of exemplification only. Functionally equivalent products, compositions and methods are clearly within the scope of the invention as described herein.

(9) 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 integer or group of integers but not the exclusion of any other integer or group of integers.

(10) Other definitions for selected terms used herein may be found within the detailed description of the invention and apply throughout. Unless otherwise defined, all other scientific and technical terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which the invention belongs.

(11) Features of the invention will now be discussed with reference to the following preferred examples.

First Embodiment of the Invention

(12) A preferred example of the first embodiment of the adjustable fin of the invention is shown in FIG. 1. FIG. 1A illustrates an exploded view (and FIG. 1B an assembled view) wherein the fin section 100 has a leading edge 102 and a trailing edge 104 and outer fin surfaces 106 of which only one is visible in FIGS. 1A and 1B.

(13) The base 200 comprises a mount 214 having two mounting blocks 202 which are compatible with the existing commercially available FCS fin plugs fitted to a majority of existing surfboards. When the adjustable fin is mounted on to a surfboard, the mounting blocks 202 are secured within FCS fin plugs and the underside surface 108 of the fin section 100 and bottom surface 204 of the base abut, i.e. align with the bottom surface of the surfboard.

(14) The base 200 comprises an insert member 206 which extends in a direction contrary to that of the mounting blocks 202. The insert member 206 comprises a planar surface with a hole 208 cut out. The hole 208 is shaped to comprise teeth 210 and valleys 212.

(15) The fin section 100 comprises a lock 110 which is shown in FIG. 1A disassembled into three components, one component comprising the button 112 of the lock 110, another component comprising a button support 116, and the other component comprising a button support pin 118 that connects the button support 116 to the button 112. FIG. 1B shows that the button 112 on the assembled fin lies flush to the outer fin surface 106. The underside of the button 112 comprises a slot 114 which when the button 112 is depressed on the assembled adjustable fin, the slot 114 aligns with the teeth 210 enabling the teeth 210 which have a width thinner than the width of the slot 114, to pass through the slot 114. The button 112 is biased towards releasably coupling the lock 110 to the insert member 206, and lying flush to the outer fin surface 106.

(16) FIG. 2 illustrates the internal mechanism and interaction between fin section 100 and base 200 when this preferred example of the first embodiment of the adjustable fin of the invention is assembled.

(17) In FIG. 2, the lock 110 is releasably coupled in a locking position formed by a valley 212 in the hole 208 of the insert member 206. The internal cavity 120 in the fin section 100 is configured to enable the insert member 206 to slidably move by manual force in a direction towards the trailing edge 104. This can take place after the lock 110 is uncoupled from the insert member 206 when the button 112 is depressed by manual force and the slot in the button 112 is aligned with the teeth 210 allowing the teeth 210 to pass through the slot of the button 112. When the lock 110 is in alignment with another locking position, for example, formed by a second valley 220, release of the button 112 will move the slot of the button 112 out of alignment with the teeth 210 and the teeth 210 will no longer be able to pass through the slot of the button 112. As a result, the lock 110 will be restrained in the locking position formed by the second valley 220 and therefore releasably coupled to the insert member 206.

(18) FIG. 3A shows an illustration of an example of the first embodiment of the adjustable fin of the invention with a mount on the base 200 which comprises a base attachment surface 230 to which an adhesive and, in some non-limiting examples, screws, are used to attach the adjustable fin to a surfboard (FIG. 3B).

Second Embodiment of the Invention

(19) In an example of the second embodiment of the present invention, an adjustable dual fin is shown in FIG. 4. The adjustable dual fin comprises the adjustable fin of the first embodiment of the invention with a fin section 300 and a base 400, wherein a second fin section 350 is attached to the fin section 300 by five attachments 310 of different lengths. Both the fin section 300 and the second fin section 350 are flat foils with substantially flat outer fin surfaces on one side and curved outer fin surfaces on the other side. The leading edge of the fin section 300 is positioned forward of the leading edge of the second fin section. Leading edge passages 352 and trailing edge passages 354 through the second fin section 350 are angled towards the curved outer fin surface which forces water to pass through the passage and into the gap between the fin section 300 and second fin section 350. The example further comprises an extended base member 410 such that when the adjustable dual fin is mounted on a surfboard, there is a gap 411 between the outer surface of the surfboard and the underside surfaces of the fin section 300 and second fin section 350. The bases of the example comprise mounting blocks which can attach to existing available FCS fin plugs.

(20) Without wanting to be limited by any one theory, it is believed that this example of the adjustable dual fin of the second embodiment of the invention provides a benefit of increased thrust and therefore speed in a direction substantially towards the front of a surfboard it is mounted to when in normal use, for the following reasons.

(21) As shown in the example in FIG. 4, the distance between the flat outer fin surface 320 of the fin section 300, and the curved outer fin surface 360 of the second fin section 350 is nearest at the peak 362 of the curved outer fin surface 360 of the second fin section 350. This distance is preferably between approximately 0.1 mm and 5 mm, more preferably between approximately 0.25 mm and 1.5 mm, and even more preferably approximately 1 mm. The proximity and position of the fin section 300 and the second fin section 350 forms a V-shaped channel 364 between the peak 362 and the leading edge 366 of the fin section 300 and the leading edge 368 of the second fin section 350, the V-shaped channel 364 extending along the curved length of the fin sections to their tips 370. On the other side of the peak 362 is a rear chamber 372 formed between the peak 362 and the trailing edge 374 of the fin section 300 and the trailing edge 376 of the second fin section 350.

(22) During normal use when mounted on a surfboard, water passes into the V-shaped channel but only a small amount of this water can pass between the thin gap between the fin section and the second fin section. The majority of the water is forced along the length of the V-shaped channel towards the tip of the fin sections at a higher velocity than the normal speed that water is passing the fin sections. This higher velocity is generated due to the higher pressure behind the water forced into the channel than the pressure of the water in front of the water leaving the channel adjacent to the tips of the fin sections according to Newton's 2nd law. In accordance with Bernoulli's principle, the increase in the velocity of the water occurs simultaneously with a decrease in pressure. Therefore, a region of low pressure is created in this V-shaped channel.

(23) Conversely, some water passes through the thin gap between the fin section and the second fin section, and passages direct water through the second fin section from the side of the substantially flat outer fin surface into the rear chamber. The effect of forcing all of this water into the limited space of the rear chamber results in the creation of a region of high pressure.

(24) The pressure differential between the area of low pressure in the V-shaped channel and the area of high pressure in the rear chamber results in a lift force acting perpendicular to the direction of the fluid flow in the V-shaped channel. That is, in a direction towards the front of the fin on a slight downward angle. The thrust provided by this lift force acts to increase the overall speed of the fins in this direction, and therefore, the board through the water.

(25) FIGS. 5B and 5D show the internal structure and mechanism from different views of the same example of the second embodiment of the adjustable dual fin of the invention shown in FIGS. 5A and 5C, respectively. FIG. 5E shows an exploded view of the same example. The bases comprise mounting blocks which can attach to existing available FCS fin plugs.

(26) Example of the adjustable fin and adjustable dual fin of the invention which have been mounted onto a surfboard are shown in FIG. 6. The mount for these examples comprises a base attachment surface which attaches to the surfboard by an adhesive. An adjustable fin according to the first embodiment of the invention is mounted to the surfboard as a centre fin. Mounted to the surfboard as side fins are adjustable dual fins according to examples of the second embodiment of the invention.