AU2019219755B2

AU2019219755B2 - Surfboard fin having a rearwardly offset bearing surface

Info

Publication number: AU2019219755B2
Application number: AU2019219755A
Authority: AU
Inventors: Xabi LAFITTE; Philippe Lopez
Original assignee: Maya
Current assignee: Maya
Priority date: 2014-09-04
Filing date: 2019-08-20
Publication date: 2022-07-07
Anticipated expiration: 2035-07-28
Also published as: PT3188961T; US20170283016A1; EP3188961B1; ES2742153T3; AU2015310758A1; AU2019219755A1; WO2016034784A1; EP3188961A1

Abstract

The invention relates to a fin for a surfboard, having a main body (12) which comprises a first edge (20) which is in contact with the board when said fin is secured to the board, a leading edge (22) at the front and a trailing edge (26) at the rear, a rear curve connecting the leading edge (22) and the trailing edge (26), the trailing edge (26) comprising a forwardmost front tip 5 (31), characterized in that the main body (12) is extended rearwards by an arm (14) which extends from a straight line which is perpendicular to the first edge (20) and passes through the front tip of the trailing edge (26), as far as the rear curve, said arm (14) having a length greater than approximately 8 cm. Figure 8

Description

SURFBOARD FIN HAVING A REARWARDLY OFFSET BEARING SURFACE

The present invention relates to a fin for a surfboard, as well as to a surfboard having such a

fin.

Surfboards generally comprise, towards the rear of the board, one or more fins arranged in

vertical planes, comprising, starting from the front, a leading edge forming a convex curve

which, as it descends, is inclined rearwards, and then a lower edge substantially forming a

tip, and, rising again at the rear, the trailing edge, generally with a concave curve.

The fins constitute vertical planes which, in the longitudinal direction, cut through the water

well to reduce drag and braking of the board and, in the lateral direction, offer high

resistance, limiting transverse movement.

The surfer can thus control the trajectory of the board, by using his feet to give said board an

orientation that will substantially constitute its direction of forward travel.

In general, fins of this type may be found on all types of surfboards for various sports which

involve surfing the water.

The fins known in the prior art are relatively compact assemblies with little lateral flexibility,

which tends to limit under all circumstances the lateral drift of the rear part of the board.

Figure 2 shows a first fin 4 comprising a first edge 20 which is up against the underside of a

board 2, forming the boundary with the anchoring portion 16.

Starting from the front of the first edge 20, there are, in succession, a leading edge 22 with a

rearwardly inclined convex curve, a very short lower edge 24 which touches the horizontal

line H at one point, and then a trailing edge 26 of concave curvature which joins up with the

first edge 20 at the rear.

There is a first axis of inclination 30, which runs from the centre 36 of the first edge 20 to the

point of contact 28 between the lower edge 24 and the horizontal line H. A first angle of

inclination 32 of this first axis of inclination is thus defined with respect to the axis 0°

perpendicular to the upper first edge, which in this example is 45°.

Figure 3 shows a second fin 4 which is shorter in the longitudinal direction. The convex curve

of the leading edge 22 and concave curve of the trailing edge 26 are more pronounced. In

this example, the first angle of inclination 32 of the first axis of inclination 30 is 27°.

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Note that in these examples shown in Figures 2 and 3, the rear end of the fin 4 forms a rear

tip 34 connecting the lower edge 24 and the trailing edge 26. For these types of fin 4, the

first angle of inclination 32 of the main axis of inclination 30 rarely exceeds 45°.

Figures 4 and 5 show commercially available fins 4 comprising a main body 12 and a rear tip

34 projecting towards the rear of this main body 12, with a large height.

The main body 12 fits inside a main rectangle 40 comprising a short side which corresponds

to the first edge 20 of the fin. A second angle of inclination 44 is defined, also called the

'sweep' angle, the angle made between the straight line passing through the middle 36 of

the first edge 20 and the upper right-hand corner of the main rectangle 40, and the

perpendicular axis 0°.

The rear tip 34 fits inside a tip rectangle 46 which adjoins the main rectangle 40. A third

angle of inclination 52 is defined, also called the 'rake' angle, the angle made between the

perpendicular axis 0° and the straight line 48 passing through the rear end 38 of the first

edge 20 and the middle 50 of the rear edge of the tip 34, which is in contact with the tip

rectangle 46.

For the fin shown in Figure 4, there is a second angle of inclination 44 of 17° and a third

angle of inclination 52 of 40.

For the fin shown in Figure 5, there is a second angle of inclination 44 of 17° and a third

angle of inclination 52 of 35°.

For the fins shown in Figures 4 and 5, the rear tip 34 is somewhat bulky, and has a large

height. However, this rear tip 34 directly attached to the main body 12 has a high rigidity in

terms of lateral bending, such that the dynamic properties of the fin are quite poor.

It would be desirable to avoid these disadvantages of the prior art.

In accordance with a first aspect of the present invention, there is provided a fin for a

surfboard, configured to be secured, alone or along with other fins, to an underside of a

board, the fin having a main body which comprises a first edge which is in contact with the

board when said fin is secured to the board, a leading edge at a front and a trailing edge at a

rear, a rear curve connecting the leading edge and the trailing edge, the trailing edge

comprising a forwardmost front tip, the main body being extended rearwards by an arm

which extends from a straight line which is perpendicular to the first edge and passes

through the front tip of the trailing edge, as far as the rear curve, said arm having a length

greater than approximately 8 cm, wherein the arm comprises a height reduction, said height

18690581_1 (GHMaers) P105289.AU.1 corresponding to the dimension of the arm perpendicular with the first edge, the arm comprising at a rear of the height reduction a bearing surface with a height greater than the height reduction. There is also described a fin for a surfboard, which is designed to be secured, alone or along with other fins, to the underside of the board, having a main body which comprises a first edge which is in contact with the board when said fin is secured to the board, a leading edge at the front and a trailing edge at the rear, a rear curve connecting the leading edge and the trailing edge, the trailing edge comprising a forwardmost front tip, characterized in that the main body is extended rearwards by an arm which extends from a straight line which is perpendicular to the first edge and passes through the front tip of the trailing edge, as far as the rear curve, said arm having a length greater than approximately 8 cm. According to an embodiment, the rear part of the arm forms a bearing surface which is spaced apart from the main body of the fin, which makes it possible to obtain maximum bending between the rear part of the arm and the main body of the fin, which is connected to the board and which is not very flexible. The fin according to the invention provides, when coming out of a turn, a propulsion and acceleration effect. It is possible to modulate the bending of the arm by adjusting the length of the arm, the dimensions, the geometry and the shapes of the bearing surface(s) located at the rear of the arm. According to another advantage, the fin according to an embodiment makes it possible, owing to the speed and the inclination of the board induced by the surfer in the trajectory, to generate lateral twisting of the arm up to the rear end thereof, along an axis perpendicular to the first edge and passing through the plane of the main body (i.e. perpendicular to the board), which increases control during the turn and which restores propulsion at the end of the trajectory when the surfer releases his weight. Advantageously, the arm comprises a height reduction, the arm comprising at the rear of the height reduction a bearing surface with a height greater than the height reduction. This feature enhances flexibility. According to other features, the height reduction is between 2 and 4 cm and/or the bearing surface has a height of between 3 and 5 cm. Advantageously, the bearing surface is separated from the board by a distance greater than approximately 7 cm.

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According to this feature, the bearing surface still performs the function of limiting the

lateral drift of the board even when it is well out of the water, for example in jumps.

Furthermore, this rear part separated from the board also makes it possible to chase the

power of the swell at depth. According to this configuration, the rear part of the arm is

positioned outside the turbulence which occurs at the surface or along the board.

Preferably, the arm has a total length of between approximately 10 and 20 cm.

According to another feature, the arm comprises at least one wing at the rear.

Tests have shown that, as wings secured to the rear end of an arm have a degree of lateral

flexibility, a dynamic reaction of these wings is obtained, which can give the board

propulsion at the end of a turn in small waves. It also provides better control of the

trajectory in medium or strong waves, which provides greater reassurance for the surfer by

virtue of the increases in speed provided by the fin.

The surfboard fin according to the invention may further comprise one or more of the

following features, which may be combined with one another.

In particular, the fin may have a first angle of inclination formed between an axis of

inclination passing through the centre of the first edge and through a central point of a lower

edge of the wing(s), and an axis perpendicular to the first edge, which is greater than

substantially 45°.

In particular, the fin may have a second angle of inclination formed between an axis of

inclination passing through the centre of the first edge and through a point of inflexion of

the leading edge, and an axis perpendicular to the first edge, which is greater than

substantially 26°.

In particular, the fin may have a third angle of inclination formed between an axis of

inclination passing through the rear end of the first edge and through the rearmost point of

the rear curve, and the axis perpendicular to the first edge, which is greater than

substantially 40°.

Advantageously, the horizontal rectangle starting from the perpendicular line drawn at the

rear end of the upper edge, in which the arm and the wings fit, has a length to width ratio of

greater than approximately 2. This configuration makes it possible to enhance the dynamic

effect of the fin.

In particular, the fin may have a wing projecting downwards from the arm.

18690581_1 (GHMaers) P105289.AU.1

According to one embodiment, the fin comprises a wing which is inclined with respect to the

plane of the main body of the fin.

The fin may comprise two wings arranged symmetrically with respect to the plane of the

main body of the fin. This ensures a degree of resistance of the fin to vertical movements.

Moreover, the fin may comprise a third wing arranged in the plane of the main body of the

fin.

The invention also relates to a surfboard having at least one fin according to one of the

preceding features.

Further features and advantages will emerge from the following description of the invention,

given by way of example only, with reference to the accompanying drawings, in which:

- Figure 1 is a side view of a surfboard comprising a fin according to the invention

positioned behind a fin according to the prior art;

- Figures 2 to 5 show criteria for measuring four fins according to the prior art;

- Figures 6 and 7 show criteria for measuring two fins according to the invention

with a long length;

- Figure 8 shows criteria for measuring a fin according to the invention with a short

length;

- Figures 9a and 9b show the reinforcement by fibres of a fin according to the

invention;

- Figures 10, 11a and 12 schematically show three types of fins according to the

invention as seen from the front, comprising a vertical single wing, an inclined double wing

and a triple wing, respectively;

- Figures 11b and 11c are side and top views, respectively, of the fin shown in

Figure 11a;

- Figures 13a, 13b and 13c are, respectively, a schematic view from the front, and

drawings seen from the side and from the front, of a fin with an inclined wing;

- Figures 14a, 14b, 14c are, respectively, side, top and rear views of a fin with a

curved double wing;

- Figure 15 is a rear view of a fin with an inclined double wing;

- Figures 16a, 16b and 16c are, respectively, side, top and rear views of a fin with a

flat double wing, - Figure 17A is a side view of a fin designed to receive removable wings,

18690581_1 (GHMaers) P105289.AU.1

- Figure 17B is a top view of wings designed to be mounted on the fin shown in Figure 17A, - Figures 17C and 17D are front views of a fin having wings which are removable, in two configurations. Figure 1 shows a surfboard 2 having a front end which is angled upwards so as to surf a wave, and at the rear, in succession along the longitudinal axis, a fin 4 according to the prior art and a fin 10 according to the invention. The fin 10 according to the invention comprises a front main body 12 which is extended upwards by an anchoring portion 16 which is inserted in the board so as to secure the fin, and has a lower edge extended rearwards by a substantially horizontal arm 14, ending in a wing 18 projecting downwards from this arm. All of the fins in the figures are shown upside down, with the upper and lower sides of these fins always referring to their position in operation, and not as they appear in these upside down drawings. Figure 6 shows a fin 10 in which the leading edge 22 of the main body 12 is extended, after its convex curve, by a lower arm edge 60, which is substantially horizontal. The lower arm edge 60 is extended by a concave curve 62 before continuing through a substantially horizontal lower edge 24 of a wing 18, which is lower. After the wing 18 is a convex curve, which ascends and continues through the upper arm edge 64, which is also substantially horizontal, before joining the trailing edge 26 at the rear of the main body 12. Thus, the same vertical plane contains the arm 14 forming a substantially straight structure which extends rearwards, attached to the base of the main body 12, and then the wing 18 descending below this arm, with relatively great lateral flexibility by virtue of the bending of the arm which supports it. Figure 7 shows a fin 10 with a shorter arm 14 having a length which is reduced by approximately half with respect to the fin shown in Figure 6. To give an idea of size, the fin shown in Figure 6 has an arm with a length greater than or equal to about 50 cm (or 20 inches). The fin shown in Figure 7 has an arm with a length of less than or equal to about 25 cm (or 10 inches) and preferably between about 10 and 20 cm (about 4 and 8 inches). As shown in Figure 7, with the rear end of the arm 14 being shifted rearwards and further away from the main body 12, bending is promoted along an axis substantially perpendicular

18690581_1 (GHMaers) P105289.AU.1 to the first edge 20, contrary to the variants of the prior art shown in Figures 4 and 5 which had only a small bending capacity along an axis substantially parallel to the first edge 20.

Such bending along an axis substantially perpendicular to the first edge 20 provides, when

exiting a turn, a propulsion and acceleration effect.

Note that the first angle of inclination 32 is 65° for the fin shown in Figure 6 and 50° for that

shown in Figure 7, which is greater than the limit of 45° which is not substantially exceeded

in known fins 4.

Figure 8 shows a fin 10 with a second angle of inclination 44 of 27° and a third angle of

inclination 52 of 50°.

Thus, the ratio of the surface area of the rear part formed by the arm 14 and the wing 18,

inscribed in its rectangle 46, to the surface area of the front main body 12 inscribed in its

rectangle 40, is 0.75, the ratio of the third angle of inclination 52 to the second 44 is 1.85,

and the ratio of the horizontal side of the tip rectangle 46 to the vertical side thereof, is 2.

The fins 10 according to the invention may be produced by any known method, in particular

by machining a blank, for example made of wood, or by moulding. It is possible in particular

to use composite materials comprising a reinforcement such as glass fibres, carbon fibres or

synthetic linen fibres, and a matrix such as a polyester or epoxy resin.

The chosen materials are distributed according to a particular arrangement, in order to

obtain the desired flexibility for each part giving the dynamic properties that it is desired to

obtain from the fin.

In particular, it is possible to produce the fin from a shaped sheet of composite material,

comprising glass fibres pre-impregnated with epoxy resin, enveloped in, as reinforcement, a

glass fibre fabric with a density of 600 g/m 2 . After the whole is polymerized, a lightweight,

very strong fin is obtained.

Figure 9a shows a fin 10 comprising carbon reinforcing fibres 70 inside the front main body

12, said fibres culminating in a tip which ends slightly above the lower edge. A degree of

flexibility is obtained through this internal reinforcement.

According to another particular feature, in addition to being able to modulate the bending

along an axis perpendicular to the first edge 20 thanks to the geometry of the fin, it is

possible to modulate this bending by virtue of the nature of the materials used. Thus, Figure

9b shows carbon reinforcing fibres 72 forming, on either side, a horizontal strip placed on

the outside, which extends over the entire length of the fin at the mid height of the arm 14.

18690581_1 (GHMaers) P105289.AU.1

Good lateral rigidity is obtained by means of these external reinforcements. By way of example, it is possible to thus rigidify fins with a very long arm so as to obtain a bearing surface which is very long and stiff. This particular feature makes it possible to increase the capacity of the board to keep a straight line in very large waves. Figure 10 shows a fin 10 comprising a single wing 18 in the same plane as the main body 12 of the fin. Figures 11a, 11b and 11c show a fin 10 comprising a double wing 18 with two downwardly inclined wings 80, forming a 'V' in front view. Figure 12 shows a fin 10 comprising a triple wing 18 with two wings 82 positioned flat opposite one another, and a third wing 88 in the plane of the main body 12, oriented downwards. The wings 18 shown in Figures 11a and 12 which comprise a horizontal component, give the board a degree of resistance in the vertical direction for keeping it in contact with the water. Figures 13a, 13b and 13c show a fin 10 comprising a wing 90 in which the part arranged below the arm 14 is slightly inclined to the side with respect to the plane of the main body 12. The inclination in this example is 45° with respect to the vertical plane. In general, the inclination may be between 15 and 75°. A number of particular dynamic effects are obtained, which may be sought with the board shown in the figures. Figures 14a, 14b and 14c show a fin 10 comprising a double wing 18 with two wings 84 fixed horizontally opposite one another at the base of the arm 14, and curved upwards and outwards. This fin design is more particularly suitable for boards for surfing standing up at front of the board ('nose riding'). Figure 15 shows a fin 10 comprising a double wing 18 with two wings 84 fixed opposite one another at the top of the arm 14, forming an upwardly open 'V. Figures 16a, 16b and 16c show a fin 10 comprising a triple wing 18 with two wings 82 fixed horizontally opposite one another at the base of the arm 14. The arm 14 arranged in a vertical plane is extended by a boss over part of the length of the wing 18, forming a third wing 88 oriented upwards. The triple wing 18 thus has a resistance both in the vertical direction with the two horizontal wings 82, and in the horizontal direction with the third wing 88.

18690581_1 (GHMaers) P105289.AU.1

Note that for this fin the edges of the arm 14 are rounded, the variable section of this arm narrowing towards the rear. The horizontal wings provide a counter support at the rear of the surfboard that allows the surfer to position himself at the front of the board, surfing the face of the wave without digging in. Generally, different shapes of wings may be associated with an arm 14 of suitable length and flexibility in order to obtain a particular dynamic behaviour of the board tailored to the skill of the surfer and the sea conditions. According to another variant shown in Figures 17A to 17D, the wings 18 are connected to the rest of the fin in a removable manner. For this purpose, the arm 14 comprises a substantially horizontal slot 92 which is open towards the front of the fin. Complementarily, the wing 18 comprises a slot 94 made in a median position, which delimits two wings 96, 96', and which is open towards the rear of the wing 18. The slots 92 and 94 are dimensioned in such a way as to allow the wing 18 to be assembled to the rest of the fin by nesting. The wing 18 may be flat or V-shaped, the slot 94 being positioned at the base of the V. According to this configuration, different wings may be successively secured to the same fin. According to another advantage, the same wing 18 may be secured in different configurations, the edges of the wings 96, 96' may be oriented downwards as shown in Figure 17C or upwards as shown in Figure 17D. According to a simplified variant, the wing 18 may be integrated into the arm 14. Whatever the variant, the fin has a main body 12 which comprises a first edge 20 which is in contact with the board when the fin is secured to the board, a leading edge 22 at the front and a trailing edge 26 at the rear, a rear curve 27 connecting the leading edge 22 and the trailing edge 26. According to a feature of the invention, the main body 12 is extended rearwards by an arm 14 which extends from a straight line which is perpendicular to the first edge 20 and passes through the front tip of the trailing edge 26, as far as the rear curve 27, the arm 14 having a length L greater than approximately 8 cm (approximately 3 inches). Preferably, the length L is between 12 and 18 cm (approximately between 5 and 7 inches) in order to obtain a degree of flexibility suitable for the acceleration and driving of the board. The front tip of the trailing edge 26 corresponds to the rear tip 38 of the first edge 20 in the case of the variants shown in Figures 6 and 7. In the case of the variant shown in Figure 8,

18690581_1 (GHMaers) P105289.AU.1 the front tip 31 of the trailing edge 26 is shifted towards the front with respect to the rear tip 38. The length L of the arm corresponds to the dimension of the arm parallel to the first edge 20. Thus, according to the invention, the rear part of the arm 14 forms a bearing surface connected by the arm 14 to the main body 12 and rearwardly offset, which makes it possible to obtain flexibility along an axis which is perpendicular to the first edge 20 and passes through the plane of the main body 12 (i.e. perpendicular to the board 2). According to another feature, the arm 14 comprises a height reduction 33, the portion of the arm and/or the bearing surface 35 located to the rear of the height reduction having a height greater than said reduction. The height of the arm corresponds to the dimension of the arm perpendicular to the first edge 20. Preferably, the height reduction is of the order of 2 to 4 cm. The bearing surface 35 has a height of between 3 and 5 cm greater than the height reduction. Advantageously, the bearing surface 35 is separated from the board by a distance greater than approximately 7 cm. In the presence of a height reduction, the leading edge comprises a point of inflection 29. A point of inflection corresponds to a point at which the leading edge crosses the tangent to the point of inflection. The leading edge 22 may comprise a straight portion, the leading edge having a convex curvature to the front of the straight portion and a concave curvature to the rear. In this case, the point of inflection corresponds to the front tip of the straight portion. Preferably, a straight line passing through the rear end 38 of the first edge 20 and the point of inflection 29 of the leading edge 22 is perpendicular to the first edge 20. In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

18690581_1 (GHMaers) P105289.AU.1

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

18690581_1(GHMaters) P105289.A.1

Claims

1. A fin for a surfboard, configured to be secured, alone or along with other fins, to an

underside of a board, the fin having a main body which comprises a first edge which

is in contact with the board when said fin is secured to the board, a leading edge at a

front and a trailing edge at a rear, a rear curve connecting the leading edge and the

trailing edge, the trailing edge comprising a forwardmost front tip, the main body

being extended rearwards by an arm which extends from a straight line which is

perpendicular to the first edge and passes through the front tip of the trailing edge,

as far as the rear curve, said arm having a length greater than approximately 8 cm,

wherein the arm comprises a height reduction, said height corresponding to the

dimension of the arm perpendicular with the first edge, the arm comprising at a rear

of the height reduction a bearing surface with a height greater than the height

reduction .

2. The fin according to Claim 1, wherein the height reduction is between 2 and 4 cm.

3. The fin according to either Claim 1 or 2, wherein the bearing surface has a height of

between 3 and 5 cm.

4. The fin according to any one of Claims 1 to 3, wherein the bearing surface is

separated from the board by a distance greater than approximately 7 cm.

5. The fin according to any one of the preceding claims, wherein the arm has a total

length of between approximately 10 and 20 cm.

6. The fin according to any one of the preceding claims, wherein the arm comprises at

least one wing at the rear.

7. The fin according to claim 6, further comprising a first angle of inclination formed

between an axis of inclination passing through a centre of the first edge and through a

18690581_1 (GHMaers) P105289.AU.1 central point of a lower edge of the at least one wing, and an axis perpendicular to the first edge, which is greater than substantially 45°.

8. The fin according to any one of the preceding claims, further comprising a second angle of inclination formed between an axis of inclination passing through a centre of the first edge and through a point of inflexion of the leading edge, and an axis perpendicular to the first edge, which is greater than substantially 26°.

9. The fin according to any one of the preceding claims, further comprising a third angle of inclination formed between an axis of inclination passing through a point where the trailing edge joins the first edge and a rearmost point of the rear curve, and an axis perpendicular to the first edge, which is greater than substantially 40°.

10. The fin according to any one of the preceding claims, further comprising a rectangle having sides, one of the sides of which coincides with a straight line which is perpendicular to the first edge and passes through a point where the trailing edge joins the first edge, in which the arm and any wings are inscribed, said rectangle having a length to width ratio of greater than approximately 2.

11. The fin according to any one of the preceding claims, further comprising a wing which is inclined with respect to a plane of the main body.

12. The fin according to any one of the preceding claims, further comprising at least two wings arranged symmetrically with respect to a plane of the main body.

13. The fin according to Claim 12, further comprising a third wing arranged in the plane of the main body.

14. A surfboard having at least one fin according to any one of the preceding claims.

186905811 (GHMaers) P105289.AU.1