RED OFTHE INVENTION

The present invention relates to a kiteboard according to the patent claims.

BACKGROUND OFTHE INVENTION Performance characteristics of kiteboards can vary widely depending on the shape of the board, the weather and water conditions. Thus, most users own various kite- boards with different performance characteristics to compensate these effects. Next to being expensive, this has the disadvantage of a high demand of storage space as well as transportation space, if various boards need to be brought along to the water side due to unknown weather and water conditions.

Water boards, such as e.g. surfboards, sail or paddle boards with different config urations, are known. In the following some examples shall be given on adaptable water boards known from the prior art.

US9650114 , published on the 1 6.05.201 7 by Maresh Joseph, relates to a modu- lar floating board. The modular floating board has a nose module, a tail module and an intermediate module. The modules may be coupled together to a functional floating board by an interface connection established between the intermediate module and the nose and tail modules. A tensioning member may compress the modules in longitudinal alignment and prevent the modules of the assembled board from separating. Each of the modules is on its own non-functional.

WO06118949A1 , published on the 09.1 1 .2006 by Thomas Meyerhoffer, dis closes a system of interchangeable components including various front panels, rear panels, adaptors, and interfaces that can be variably and removably assembled to form various customized waterboards with various performance characteristics.

DE202014006073 , published on the 25.09.201 4 by Skywalk GmbH and Co KG, discloses a separable board with at least two parts, which are connectable via a connection device. The connection device has a locking device for locking the con- nected portions and at least two bolts, with the bolts being anchored firmly in a part of the board and being insertable into respective holes of the other part of the board.

CN203345156 U, published on the 1 8.1 2.201 3 by Hongzhou Liangjin Boat Co LTD, relates to an assembly, combining a surfboard, a paddle and a sailing boat in one structure. The assembly comprises a base plate, an end buckle plate, a left buckle plate and a right buckle plate, wherein the end buckle plate is of a U shape. The assembly can be used as a surfboard, a paddle board, or sailing boat by fixedly assembling different parts together.

The boards known from the prior art are difficult to assemble and non-practical for easy transportation. SUMMARY OFTHE INVENTION

It is an object of the invention to provide a kiteboard, which is adaptable to a wide range of different conditions. A further object of the invention is to provide a board which can be easily stored and transported in a space-saving way. A kite board according to the invention comprises a base, at least one front exten sion and/ or at least one back extension. The base comprises a top face and a bot tom face and an outer edge face. The top face is hereby understood as the face, on which the rider stands during riding and the bottom face as the face that during riding is placed in the direction of the water. The outer edge face of the base is extending in a circumferential direction along an outer contour of the top face and the bottom face and comprises a first mechanical interface. The front extension and/ or the back extension also comprise a top face and a bottom face. Further more they comprise an inner edge face. The inner edge face extends between the top face and the bottom face along an inner contour in a circumferential direction and is shaped such that it corresponds at least partially to the outer contour of the base. The inner edge face of the front and/ or the back extension comprises a sec ond mechanical interface, which - in an assembled position - is foreseen to be engaged with a corresponding first mechanical interface of the base. The first and the second interface are engaged with each other to position the front extension, respectively the back extension with respect to the base. Alternatively or in addition, the first and the second mechanical interface can be arranged adjacent to the inner and the outer edge face in the area of the top face. By combining the base with different front and/ or back extensions the width (in a lateral direction) and/ or the length (in a longitudinal direction) of the overall kite- board may be adjusted. Hence, a modular setup can be arranged with a fully func tional base and one or several front and back extension. One base can be intercon- nected with one or several front and back extensions via the first and the second mechanical interface thereby covering the full spectrum of different applications of a kiteboard. Thus, for each user an individual a kit may be provided comprising a base and at least two front extensions and/ or at least two back extensions such that a user can exchange the front and/ or back extension to generate different kiteboards with different performance characteristics. In some applications, the base may thereby be a fully functioning kiteboard in itself. In the situation where the base acts as a kiteboard, the outer edge face of the base, respectively transition region of the outer edge face and the bottom face of the base are developed as a so called riding edge which, during riding, is actively taking influence on the riding behavior as it interacts with the water surrounding the kiteboard. In this case the edge acts as flow breakaway edge. Thus, a riding edge is preferably optimized fluid-mechanically as well as in terms of the structural properties since a riding edge experiences a stronger wear than e.g. the top face of a kiteboard. Therefore the edges of kiteboards, respectively the riding edges, are usually strengthened. This may be done e.g. by turning over the fibers at the edge of a fiber reinforced board such that no ends of fiber layers are exposed at the outer edge face and/ or by using reinforcing fill materials at the edges. Additionally or alternatively, the riding edge may comprise a reinforcing element, preferably a reinforcing strip which in placed on and thus reinforces the outer edge face. The reinforcing element may e.g. be made from ABS-plastic. If the base can be used as a kiteboard, the base may rep resent a narrow kiteboard board which is known to be faster than a wider board. A kiteboard with a greater width can be generated by combining the base with a front and / or a back extension which is results in more stable driving characteristics. Pref- erably, the width of the base is between W _B = 0.26 - 0.38m such that is may be used without front or back extensions. Advantageously, the width of the kiteboard can then be extended up to W _K = 0.5m in various steps by using different front and/ or back extensions. Depending on the application the length of the base may be changed together with the width or independently. Next to the width and the length of the kiteboard, the shape of the overall contour of the kiteboard can be adapted. This may be done by either using both extensions (front and back extension), having different shapes or by using only one of the front or the back extension. E.g. the base may be a so-called "twin-tip" kiteboard, as known from the prior art, which has a symmetrical and longitudinal form and can be used in the positive and the negative longitudinal direction. However, in combination with the front and/ or the back extension an overall shape of a (non- symmetrical) raceboard may be generated. Depending on the application, the front and/ or back extension may further comprise an additional floating member.

For the interconnection of the base with the front and or the back extension, the first and the second mechanical interface can comprise a notch and a thereto cor responding tongue at least partly over the circumferential length of the outer edge face and/ or the inner edge face. Alternatively or in addition other mechanical in terconnection means e.g. such as pins insertable in respective holes may be used. Preferably, the notch is arranged in the outer edge face of the base and the tongue is arranged in the inner edge face of the front and/ or the back extension. If the outer edge face of the base is riding edge, as described above, such that the base may be used as a kiteboard alone (without the first and the second extension), this setup is advantageous in terms of water -board interaction since a tongue extend ing from the base creates unnecessary drag and affects the overall board perfor mance in a negative way. Advantageously, the front extension and/ or the back extension extend in the as sembled position around the base and meet each other at a widest area of the base of the kiteboard, i.e. approximately in the middle with respect to the longitudinal direction of the kiteboard. The widest area is hereby defined as the area where the base has in a lateral direction the greatest width (with the kiteboard extending in longitudinal direction). The front extension may additionally comprise a third me chanical interface on a side face between the top and the bottom face foreseen to abut against a respective forth mechanical interface of the back extension on a side face between the top and the bottom face of said back extension. The third and fourth mechanical interfaces may also comprise a notch and a thereto correspond- ing tongue engaging into each other, as described above.

For an advantageous fluidic design, the bottom face of the front extension and/ or the back extension in the assembled position continuously merges into the bottom face of the base. Thus, if the kiteboard is moved over the water surface, the drag is minimized due to a smooth surface with no abrupt gradients in the bottom face due to the interconnection of the base to the front and/ or back extension.

For a stable interconnection at least one first locking element may be present to (releasable) lock the front extension and/ or the back extension with respect to the base in the assembled position. The locking element hereby preferably intercon nects (respectively the application of interconnection forces), the base, the front and / or the back extension in longitudinal and in lateral direction of the kiteboard, which yields a more robust structural interconnection. Alternatively or in addition to that, the at least one first locking element may also lock the front extension with respect to the back extension in the assembled position. For an advantageous de sign in terms of the fluidic drag, the at least one first locking element is hereby pref erably located on the top face of the base and/ or top face of the front extension and / or the back extension, where no direct water-board interaction takes place. A placement on an outer side face of the kiteboard (extending between the top face and the bottom face in circumferential direction around the kiteboard) is also dis advantageous, since the design and shape of the kiteboards edge is also known to influence the board's performance.

In a preferred variation of the invention, the at least one first locking element com- prises a tension element, at least two deflecting members and one cord. Hereby, the cord is wound around the at least two deflecting members and the tension el ement tightens the chord around said deflecting members. The deflecting member deflects the cord in a way that a deflection angle is generated between the incom ing cord and the outgoing part of the cord at the deflecting member. Preferably, the deflecting member features therefore a guiding indentation such that the chord is prevented from slipping of. In one variation, the tension element may also deflect the chord. The advantage of this arrangement is the easy handling and the possi bility to assemble different combinations. A further advantage is the low profile ar rangement which does not significantly stick above the top surface of the board.

If the parts which shall be interconnected are engaged by means of the first and the second mechanical interface (pre-assembled position), the cord is wound around the respective deflecting members and tensioned by the tension element. For an easy storage of the cord it is further advantageous, if the tension member com prises a feeder roll wish can stash excessive cord and/ or the cord over the full cord length if the cord is not in use.

If both extensions (front and back extension) are used, two first locking elements are preferably placed on the top face of the base and/ or the top face of the front and/ or the back extension, with each locking element located in the area of the intersection of the base, the front extension and the back extension. In this case, at least three but preferably four deflecting members may be used for each locking element. In the case of four deflecting members, the cord forms a rectangle with a deflecting member at each corner of the rectangle, deflecting the cord by 90deg. Thus, if one deflecting member is placed on the front extension, one deflecting member on the back extension and two deflection members on the base the front extension and the back extension are secured against each other meanwhile at the same time the front and the back extension are secured, respectively braced, against the base and against each other- which generates strong and evenly bal anced interconnection forces in the lateral as well as longitudinal direction if the cord is retensioned by the tension member. The latter is hereby preferably placed along a straight part of the (rectangular formed) chord on either part of the kite- board (base, front or back extension) such that only uni-directional forces apply on the tension member.

For a space saving design, the base may further be dividable in at least two parts. This minimizes further the transportation space needed. Therefore a first and a sec ond base part may be provided, each comprising an interconnection face extending between the top face and the bottom face of the base foreseen to abut against each other. Each interconnection face may comprise a mechanical interface, as de scribed above. Furthermore, the first and the second base parts may be secured in an interconnected position by the at least one first locking element in the same way as described above and/ or by at least one second locking element, interconnecting the first and the second part of the base independently. The second locking element may be e.g. a buckle.

In a further variation of the invention, at least one fin is releasably attached to the base and/ or the front extension and/ or the back extension. Therefore, the base and/ or the front extension and/ or the back extension may comprise at least one first insert for the attachment of the fin on the bottom face. Since the optimal place ment of a fin depends on the size of each board, the fin's position is preferably adaptable. Furthermore, the exact placement influences certain board characteris tic such as the turning ability and the grip. Therefore, advantageously, different fins having different sizes and shapes may be places on various locations on the kite- board and can be easily exchanged and/ or relocated. The fin may e.g. be attached by means of a thread or a guick fastener. Depending on the application, the base may comprise at least one second insert for the releasable attachment of a foil on the bottom face. Due to the higher forces on a foil in respect to the forces on a fin, the second insert may be designed, respectively scaled, differently than the first insert. Furthermore, the front and/ or back extension may comprise an additional floating member to compensate the added weight of the foil. Preferably, the first and the second inserts are designed in a way that no reach-through is generated from the bottom face to the top face. Otherwise the pressure differences from the top and the bottom face, caused by the moving kiteboard, might cause the water to be pressed though the insert when the kiteboard is in use and create a fountain.

It is to be understood that both the foregoing general description and the following detailed description present embodiments, and are intended to provide an over view or framework for understanding the nature and character of the disclosure. The accompanying drawings are included to provide a further understanding, and are incorporated into and constitute a part of this specification. The drawings illus trate various embodiments, and together with the description serve to explain the principles and operation of the concepts disclosed. BRIEF DESCRIPTION OFTHE DRAWINGS

The herein described invention will be more fully understood from the detailed de scription given herein below and the accompanying drawings which should not be considered limiting to the invention described in the appended claims. The draw- ings are showing:

Fig. 1 A first variation of the kiteboard according to the invention in the assem bled position in a perspective view;

Fig. 2 a detail of the kiteboard according to Figure 1 ;

Fig. 3 a first variation of a kiteboard kit in a partly disassembled position in a perspective view;

Fig. 4 a detail of the kiteboard kit according to Figure 3;

Fig. 5 a second variation of the kiteboard according to the invention having an additional fin in a perspective view from below

Fig. 6 a third variation of the kiteboard according to the invention having an additional foil in a perspective view from above;

Fig. 7 the kiteboard according to Figure 6 in a perspective view from below. DESCRIPTION OFTHE EMBODIMENTS

Reference will now be made in detail to certain embodiments, examples of which are illustrated in the accompanying drawings, in which some, but not all features are shown. Indeed, embodiments disclosed herein may be embodied in many dif- ferent forms and should not be understood as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal reguirements. Whenever possible, like reference numbers will be used to refer to like components or parts.

Figure 1 shows a first variation of the kiteboard 1 according to the invention in a perspective view and in the assembled position from above. The shown kiteboard 1 comprises a base 2, a front extension 3 and a back extension 4 such that the front extension 3 and the back extension extend around the base 2 and meet each other at a widest area (in the lateral direction y) of the base 2. It can further be seen that in the shown variation the base 2 may be divided in a first part 2a and a second part 2b. In the perspective view of Figure 1 , a top face 5 of the base 2, respectively a top face 1 0 of the front and the back extension 3, 4 are facing upwards (positive z-direction) and can be thus seen in said view. In the assembled position an outer side face 7 extending in a circumferential direction along an outer contour 8 of the top face 5 and the bottom face 8, cannot be seen directly however, an edge of the top face 5 of the base 2 being flush mounted to an edge of the top face 1 0 of the front and back extension 3, 5 can be detected. Furthermore, it can be seen that the bottom face 1 1 of the front extension 3 and/ or the back extension 4 in the assem bled position advantageously merge continuously into the bottom face 6 of the base 2, such that fluidic drag can be reduced, when in use.

On the top faces 5, 1 0 first and second locking elements 1 6, 24 can be seen, which are illustrated in more detail in Figure 2. The first locking element 1 6 locks the front extension 3 and/ or the back extension 4 with respect to the base 2 in an assembled position. Preferably, the at least one first locking element 1 6 also locks the front extension 3 with respect to the back extension 4 in the assembled position. Mean while, the first and the second part 2a, 2b of the base 2 may be interconnected separately by at least one second locking element 24, placed on the top face 5 of the base 2. The first locking element 1 6 herby comprises preferably a tension ele ment 21 , at least two deflecting members 22 and one cord 23. Hereby, the cord 23 is first wound around the at least two deflecting members 22 in a pre-assem- bled position (with the base and front and/ or back extension interconnected at least through the first and second mechanical interfaces) and then the tension ele ment 21 tightens the cord 23 around said deflecting members 22. In the shown application, the deflecting member 22 deflects the cord 23 by a deflecting angel of alpha = 90 deg between the incoming cord 23i and the outgoing part of the cord 23o at the deflecting member 22 (compare Figure 2, deflection member 22d). However, depending on the amount of deflecting members 22 used, the deflection angle may vary. To avoid that the cord 23 may slip from the deflecting members 22, the deflecting members 22 may comprise a guiding indentation 25, in which the cord 23 is guided and secured over the length of the deflection. (In the assem bled position the cord 23 is taut and thus straight between each deflecting member 22. )

In Figure 3 a kit 28 is illustrated comprising a base 2 and at least two front exten- sions 3a, 3b and/ or at least two back extensions 4a, 4b (3b not shown here). In the shown example, combining the base 2 with the back extension 4a and the re spective front extension 3a generates a wider and also a longer kiteboard 1 a than a kiteboard 1 b using the base, the front and back extension 3b, 4b. However, also other front and back extensions shapes may be used in a kit 28. The illustrated kite- board kit 28 can be seen in a partly disassembled position which offers a view on the outer and inner edge faces 7, 1 2. An outer edge face 7 of the base 2 can be seen that is extending in a circumferential direction along an outer contour 8 of the top face 5 and a bottom face 6. Said outer edge face 7 is comprising a first me chanical interface 9 for the interconnection of the front and/ or the back extension via a second mechanical interface 1 3 of the front and/ or the back extension. Hereby an inner edge face 1 2 of the front and/ or the back extension extends be tween the top face 1 0 and the bottom face 1 1 , corresponds at least partially to the outer contour 8 of the base 2 and comprises said second mechanical interface 1 3. In the assembled position the first and the second mechanical interfaces 9, 1 3 are engaged with each other to position the front extension 3 and/ or the back exten sion 4 with respect to the base 2. In the illustrated case, the first and the second mechanical interface 9, 1 3 comprise a notch 1 4 and a thereto corresponding tongue 1 5 with the notch 1 4 being arranged in the outer edge face 7 and the tongue 1 5 being arranged in the inner edge face 1 2. However, other mechanical interconnection means such as e.g. pins party insertable in respective holes may be used.

In Figure 5 a second variation of the kiteboard 1 according to the invention can be seen from a perspective view from below on the bottom faces 6, 1 1 . In this varia tion the kiteboard 1 further comprises at least one first insert 1 7 to which at least one additional fin 1 8 may be attached. In the shown application two (not used ) first inserts 1 7a, 1 7b are located in the base 2. Furthermore, in total four fins 1 8a, 1 8b are illustrated attached to the base 2 and the back extension 4 via further first inserts 1 7, which are concealed by the presence of the fins 1 8a, 1 8b. However, a user may change the position of the fins 1 8a and 1 8b due to personal preferences or according to the local weather and water conditions using other insert positions such as e.g. the positions of the first inserts 1 7a, 1 7b. The amount and the position of the first inserts 1 7 may vary depending on the individual application. In the variation of the kiteboard 1 according to Figure 1 to Figure 5, the base 2 as well as the overall kiteboard 1 have a shape of a so-called twin-tip board with the front and back extensions 3, 4 being essentially U-shaped. However, other shapes of base2, the front and back extensions 3, 4 are also possible: The fins 1 8a 1 8b as illustrated in Figure 5 are therefore also applicable to a kiteboard 1 in the shape of e.g. a raceboard. Figure 6 and Figure 7 illustrate a third variation of the kiteboard 1 according to the invention. Figure 6 shows the perspective view on the top face 5, 1 0 and Figure 7 on the respective bottom face 6, 1 1 . The third variation of the kiteboard 1 is an example of the front extension 3 and the back extension 4 being different from each other such that an overall new shape of the kiteboard 1 is generated in view of the base 2. In this case, the base 2 has the shape of a "twin-tip" board, mean while the kiteboard 1 in the assembled position has the shape of a race board, which has a greater extension in longitudinal direction and may additionally feature a triangular cutout 29 at the end of the back extension. Additionally, the kiteboard 1 may be supplemented with a foil 20. In this variation the kiteboard 1 therefore comprises at least one second insert 1 9 over which at least the additional foil 20 may be attached. Due to the higher forces acting on the foil 20, the at least one second insert 1 9 may be larger in dimension than the first insert 1 7. Additionally of alternatively, the base 2 may comprise a feed-through to insert part of the foil 20 and fixate the foil 20 on the top face 5 (not shown here).

The words used in the specification are words of description rather than limitation and it is understood that various changes may be made without departing from the spirit and scope of the invention. LIST OF DESIGNATIONS

1 Kiteboard 1 6 First locking element

2 Base 1 7 First insert

3 Front extension 1 8 Fin

4 Back extension 1 9 Second insert

5 Top face (base) 20 Foil

6 Bottom face (base) 21 Tension element

7 Outer edge face 22 Deflecting member

8 Outer contour 23 Cord

9 First mechanical interface 24 Second locking element

1 0 Top face (extension) 25 Guiding indentation

1 1 Bottom face (extension) 26 Third mechanical interface

1 2 Inner edge face 27 Forth mechanical interface

1 3 Second mechanical inter 28 Kit

face 29 Cut-out

1 4 Notch 30 Inner contour

1 5 Tongue