Fin

Abstract

The invention relates to a fin, in particular for a flow body such as a surfboard, wherein the fin comprises a connection wall (1) for connection to the flow body, as well as at least two side walls (2a, 2b), wherein at least two of the side walls (2a, 2b) are each connected, in the region of an upper end (2g), to the connection wall (1) and, in the region of a lower end (2h), to one another via a bottom wall (3), and a flow channel (4) having a longitudinal axis (L), at least one first opening (5) and at least one second opening (6) is thus formed by the side walls, the bottom wall (3) and preferably also the connection wall (1), wherein at least one side wall (2a, 2b) has a depth-to-length ratio of less than 1.5, characterised in that at least one side wall (2a, 2b) has, along its entire extension along the longitudinal axis, an obtuse inner angle (A) to the connection wall (1) at least in portions.

Description

[0001] Find

[0002] The invention relates to a fin, in particular for a flow body such as a surfboard, wherein the fin has a connecting wall for connection to the flow body, and at least two side walls, wherein at least two of the side walls are each connected to the connecting wall in the region of an upper end and are connected to one another via a bottom wall in the region of a lower end, and thus a flow channel with a longitudinal axis and with at least one first opening and at least one second opening is formed by the side walls, the bottom wall and preferably also the connecting wall. Fins serve to stabilize the movement of objects in a flow, in particular in air or water currents. They are used in the field of flying objects, but also in vehicles and other means of locomotion and in particular watercraft, especially in sports.For example, they help with propulsion on ships, surfboards, and especially kitesurfboards by directing the flow of the fluid, i.e., air or water. The flow body is preferably a water flow body, i.e., a flow body used for flow in water. In such a case, the water represents the fluid.

[0003] Such fins should be very thin to provide low drag, but also strong enough not to break during handling. At the same time, they should enable a particularly stable ride.

[0004] Fins are typically arranged on the surfaces of flow bodies. Space on these surfaces is often limited, as they often feature flow features such as relief, grooves, flow walls, or the like. If fins extend over such flow features, their function can be disrupted, negatively impacting the stability of the flow body in the flow.

[0005] EP 1 272 388 A1 discloses a fin with two side walls, wherein a central wall between the side walls has a section of its leading edge offset rearward along the longitudinal axis in the region of the connecting section. In contrast, in the region of the bottom wall, the leading edge is arranged at the same height. The two side walls are arranged symmetrically at the same height. The water flowing through the channel formed by the side walls is divided by the central wall, but is otherwise not subjected to any significant flow change - even if the first opening of the channel is subjected to an oblique flow. Furthermore, the fin must either

[0006] Water penetration, or the connecting wall and the fin itself must be designed to be sufficiently wide so that the cross-section of the channel is sufficiently large for effective stabilization. Such a design therefore only allows for insufficient stabilization at large angles of attack and occupies a large area on the flow body. This can lead to disruption of the flow devices on the flow body.

[0007] WO 2013071329 A1 also discloses a fin with three walls, wherein the lengths of the walls are identical along the flow direction and are offset from one another. This results in the opening having a larger inflow area than the cross-section of the resulting channel, particularly in the case of an oblique inflow. This leads to an acceleration of the flow in the channel. However, the equality of the cross-sections means that the second opening has exactly the same offset, meaning that the effect can only be partially exploited, which is particularly problematic with limited component lengths. Furthermore, the walls are essentially parallel to one another, which means they must be very high in order to form large cross-sections. While this enables high efficiency, it reduces mechanical stability and increases the risk of injury when wearing and using the fin.

[0008] The object of the invention is therefore to provide a fin which enables particularly effective, strong stabilization of the ride, but is also robust and easy to assemble, and has the lowest possible risk of injury.

[0009] This object is achieved according to the invention in that at least one side wall has a depth-to-length ratio of less than 1.5, preferably less than 1, and in that at least one side wall has, at least in sections, an obtuse interior angle to the connecting wall along its entire extension along the longitudinal axis.

[0010] By sloping at least one side wall, the cross-section and area of ​​the openings are expanded without requiring a significantly larger connecting wall. This improves the flow behavior, but also does not impede any flow reliefs that may be provided on a flow surface where the fin is arranged. At the same time, the required height of the fin is reduced, resulting in a more stable design and a lower risk of injury.

[0011] Due to its use in kitesurfing, the size of the fin is more limited than in other water sports. The invention is particularly advantageous for kitesurfing fins, as it achieves good stabilization despite requiring little space on the board and the shallow depth due to a smaller design.

[0012] The blunt inner angle results in a fin that isn't too deep, yet still provides sufficient grip. Furthermore, the blunt inner angle ensures that the fin extends deeper into the water when the fin is swung. This improves the fin's effectiveness when swung. This is particularly advantageous for water-flowing bodies like surfboards, as these are typically used in a swung position.

[0013] By "sections," we mean that at least one section of the side wall is provided that has an obtuse interior angle along its entire extension along the longitudinal axis. The interior angle can also vary along the extension along the longitudinal axis. This section is preferably arranged in the region of the connecting wall, and particularly preferably, the section is arranged on the connecting wall.

[0014] An obtuse interior angle is defined as an interior angle greater than 90°. The interior angle is defined as the angle defined in the cross-section of the flow channel.

[0015] The connecting wall is preferably a single, uninterrupted wall. However, it can also be provided that the connecting wall is divided into several partial walls that are not or only partially connected to one another. The connecting wall serves to connect to an adjacent component such as a flow body, for example an outer wall of a hull, such as the underside of a surfboard. It can be provided that the connecting wall has a continuous or interrupted connecting surface or is essentially formed by this connecting wall. This connecting surface is arranged outside the flow channel and is preferably designed to bear at least partially against the flow body.

[0016] The connecting surface is a surface, usually flat, along which the connection to the flow body is established. It is usually defined by a surface of the connecting wall.

[0017] The depth-to-length ratio of a sidewall means the depth of the sidewall divided by the length of the sidewall along the longitudinal axis.

[0018] Depth extension refers to the maximum extension of the side wall from a connecting plane defined by the connecting wall. The connecting plane is the plane along which the connecting wall abuts the flow body. It is therefore the extension normal to the plane. As a rule, the connecting plane extends along the connecting surface, if present. Under certain circumstances, the connecting plane may be uneven, curved, or bent. This is particularly advantageous when the surface of the flow body is uneven, for example, bent or bent.

[0019] A depth-to-length ratio of less than 1.5 ensures that the fin does not protrude too far from the flow body, while still achieving sufficient effect. It is particularly advantageous if the depth-to-length ratio is less than 1, as this achieves a particularly good balance between strong effect and minimal protrusion. Preferably, at least two of the side walls are each connected to the connecting wall at a distance from one another in the region of an upper end. "Each connected to the connecting wall at a distance from one another in the region of an upper end" means that the side walls are spaced apart from one another in the region of their upper ends. The connecting wall is arranged at least partially between them. This allows for a significantly larger cross-section of the flow channel and, at the same time, enables the flattest possible design.

[0020] The connecting wall preferably has at least one connecting element and / or at least one connecting section for a connecting element for connection to an adjacent part. Preferably, at least one connecting section comprises at least one opening through which a screw or similar connecting element can be passed. The opening is preferably threadless.

[0021] By "that the leading edge regions of the two side walls are offset from each other along a longitudinal axis of the flow channel," we mean that one side wall begins earlier along the longitudinal axis than the other. The leading edge regions are therefore arranged at different heights along the longitudinal axis. Due to the offset, one side wall extends further forward in the front area than the other.

[0022] If the leading edge regions have an angle to the longitudinal axis that is greater or less than 90°, the above feature means that the leading edges of the two side walls along a longitudinal axis of the flow channel are offset from one another at the same height along a vertical axis of the flow channel.

[0023] The vertical axis of the flow channel is an axis perpendicular to the longitudinal axis and extends from the connecting wall toward the bottom wall. Typically, the vertical axis is perpendicular to the connecting wall. The offset is preferably present along the entire length of the edge areas. Alternatively, the offset is present in the area of ​​the upper edges, in the area of ​​the lower ends, and / or in the areas between the upper and lower ends of the side walls.

[0024] The longitudinal axis is an axis that extends along the flow channel, which is usually straight. If the flow channel is curved, the longitudinal axis can be curved accordingly.

[0025] It is preferably provided that the side walls are arranged at least partially at the same height along the longitudinal axis and / or that the side walls have lengths along the longitudinal axis which are preferably of different sizes.

[0026] By "that the side walls are arranged at least partially at the same height along the longitudinal axis," we mean that there is at least one area along the longitudinal axis that both side walls reach. Thus, at this height, both side walls delimit the flow channel. In combination with the offset in the case of oblique flow, this enables an accelerated and therefore particularly stable flow in the fin.

[0027] In addition to the side walls, the bottom wall, and preferably also the connecting wall, other parts may be involved in defining the flow channel. For example, the fin may have additional parts or elements that are involved. It may also be the case that parts or elements of the flow channel only become part of the water sports equipment when the fin is properly installed. For example, the underside of a surfboard can become part of the flow channel and at least partially define its upper and / or side boundaries.

[0028] Leading edge areas or trailing edge areas refer to the front ends of the side walls. These can include real, for example, sharp edges. They can also have flat or preferably curved edge surfaces.

[0029] The lower ends of the side walls are connected to each other via a bottom wall. Preferably, at least one lower end of at least one side wall is directly connected to the bottom wall.

[0030] It can be provided that at least one side wall has at least one extension or projecting part that extends beyond the upper end or below the lower end. It can also be provided that at least one extension or projecting part is arranged in the flow channel. For example, these can comprise at least one guide body. Guide bodies refer to devices that can influence or guide the flow; for example, these can be flow obstacles, guide walls, or the like.

[0031] It is preferably provided that the side walls, the bottom wall and the connecting wall form a hollow profile in which the flow channel is arranged.

[0032] Preferably, the cross-section of the flow channel is asymmetrical at least in sections.

[0033] Preferably, at least one side wall has a twist, at least in sections. Twist refers to a rotation of at least one section of the side wall around its extension direction from the connecting wall to the bottom wall. Such a twist, also called a wing twist, enables a better distribution of lift along the side wall and thus improved airflow.

[0034] Preferably, the length of at least one side wall tapers at least partially along the vertical axis toward the bottom wall. Such a taper can also improve the flow behavior of the side wall. In this sense, it can be provided that the taper ratio starting from the connecting wall is less than 1 and preferably greater than 0.

[0035] Preferably, at least a portion of at least one side wall, preferably at least one side wall, particularly preferably both side walls and very particularly preferably the fin, has a modulus of elasticity which is below 4,000 MPa, preferably below 3,000 MPa, preferably below 2,500 MPa, particularly preferably below 2,000 MPa and very particularly preferably below 1,700 MPa or below 1,300 MPa.

[0036] Preferably, at least a portion of at least one side wall, preferably at least one side wall, particularly preferably both side walls and very particularly preferably the fin, has a modulus of elasticity which is above 200 MPa, preferably above 400 MPa, particularly preferably above 500 MPa and very particularly preferably above 700 MPa.

[0037] A modulus of elasticity in these areas enables flexible behavior and bending or twisting of the fin depending on the flow, whereby the shape of the fin is automatically adapted depending on the current flow. This leads to particularly advantageous flow behavior in a wide variety of flow situations. Especially when the sidewall whose leading edge area

[0038] If the fin's longitudinal axis is offset further forward than that of the other side wall, and is located further away from the device's longitudinal axis of the immersion surface than the other side wall, the ranges of the modulus of elasticity just discussed are advantageous. This is because the fin is then deformed particularly preferentially by the incoming airflow. This is because deformation caused by a torque along the fin's longitudinal axis, which arises, for example, from aerodynamic or hydrodynamic forces, can cause a twist in one or more side walls. The direction and extent of the twist depend on factors such as the longitudinal offset and length, the depth and flexibility of the side walls, their overlap, and the placement, shape, and flexibility of the bottom wall.

[0039] Furthermore, it can be provided that the side walls in the region of the first opening have leading edge regions and that the leading edge regions of the two side walls are offset from one another along the longitudinal axis of the flow channel, and that it is preferably provided that the side walls in the region of the second opening have trailing edge regions and the trailing edge regions of the two side walls are offset from one another along the longitudinal axis of the flow channel. This offset of the leading edge regions achieves acceleration inside the flow channel, particularly in the case of oblique flow, without the cross-section having to be narrowed. At the same time, the flows outside the fin are advantageously guided so that no undesirable turbulences, which would have a braking effect, occur. This stabilizes the flow and achieves particularly stable movement within the flow.The offset of the trailing edge regions is particularly advantageous when the fin may be subjected to reversed airflow. This can be particularly advantageous for surfboards such as kitesurfboards. Alternatively, the side walls can also have trailing edge regions in the area of ​​the second opening, and the trailing edge regions of the two side walls are not offset from each other along the longitudinal axis of the flow channel.

[0040] Fins as described in this document may be provided, in which the depth-to-length ratio of both side walls is 1 and / or greater than 1, preferably less than 1.5. In such a case, it is particularly advantageous if the side walls have leading edge regions in the region of the first opening and the leading edge regions of the two side walls are offset from one another along the longitudinal axis of the flow channel.

[0041] The first opening is the opening through which the water at least partially flows in during intended use. Accordingly, the second opening is the opening through which the water at least partially flows out during intended use. It can be provided that the fin is temporarily supplied with water from the other side depending on the situation. In this case, one opening can function as the first and second opening, and another opening can function as the second and first opening, accordingly. It is essential for the invention that the water at least partially flows into the first opening during at least one intended use.

[0042] Preferably, at least one side wall, preferably both side walls, have a preferably asymmetrical profile. It can also be provided, or instead, that the bottom wall and / or the connecting wall have a preferably asymmetrical profile. For the profile to be effective, it must be aligned with the flow. "Profile" refers to an aerodynamic profile, called an "airfoil." Accordingly, it is advantageous if the profile extends along the length of the side wall. Preferably, at least one profile comprises an airfoil.

[0043] If at least one sidewall has a profile, the chord line can be used to determine the length of the respective sidewall. In some cases, it may also be useful to use the camber line to determine the length. In this sense, the sidewalls can be provided with chord lines and / or camber line lengths of different sizes.

[0044] It may be provided that the maximum length of a wall, such as a side wall, is used when determining the length. Alternatively, an average value, preferably an average value of the chords or the skeleton lines of the wall, can be used. This is particularly advantageous if the length of the wall, its chord, or its skeleton line changes transversely to its extension along the side wall.

[0045] Furthermore, it can be provided that the leading edge area of ​​at least one side wall has an opening angle of less than 90°, preferably less than 80°, and particularly preferably less than 70° with respect to the connecting wall. This refers to the inner angle, i.e. the angle pointing towards the fin. This achieves a sloping and large surface area of ​​the first opening. A straight surface reduces the cross-section of the opening and massively increases the flow resistance, offering no advantage with respect to its position in the flow when the board is edged. Furthermore, such an angle allows foreign objects to slide off easily. Furthermore, it can be provided that the leading edge area of ​​at least one side wall has an opening angle of roughly 4° with respect to the connecting wall. U, preferably greater than 45° and particularly preferably greater than 50°. Smaller angles result in significantly shortened sidewalls or significantly elongated fins, which is detrimental to the flow behavior.

[0046] Preferably, the distance between the side walls along the longitudinal axis remains essentially the same, at least in sections. Small differences in distance, which may arise, for example, from a change in the thickness of one or both side walls or a twist, for example due to at least one profile of at least one side wall, are harmless. This avoids an increase in flow resistance. If the side walls are at an angle to one another, i.e. are not parallel to one another, it is advantageous if the distance between the side walls along the longitudinal axis remains essentially the same, at least in sections, at least at one height along a vertical axis.

[0047] It may also be advantageous that the average distance of the side walls, averaged along the vertical axis, remains the same along the longitudinal axis, at least in sections.

[0048] It can be provided that the floor wall has at least one wall section that is at an angle to the connecting wall. "At an angle" means that the chord of the wall section of the floor wall is not parallel to the connecting wall.

[0049] It can be provided that at least one side wall has at least two wall segments that are positioned at different angles to the connecting wall. This allows the cross-section of the flow channel to be precisely adjusted and the flow to be optimized.

[0050] It is also advantageous if the cross-sectional area of ​​the flow channel remains essentially the same along the longitudinal axis. This ensures that there is no increase in flow resistance. The shape of the cross-section of the flow channel can change along the longitudinal axis or remain the same.

[0051] It is particularly advantageous if it is provided that the upper end of at least one side wall and the lower end of the same side wall are arranged at least partially at the same height along the longitudinal axis. This optimizes the flow in the flow channel and the flow channel is completely delimited by the side wall. Furthermore, it is advantageous if it is provided that at least one side has an obtuse internal angle to the connecting wall at least in sections and preferably has an internal angle to the connecting wall between 91° and 140°, particularly preferably between 100° and 140°. The internal angle is particularly preferably less than 125° and most preferably approximately 115°. This expands the flow cross-section of the flow channel. In the case of a flow body, it is particularly advantageous if this side wall is the side wall that is further away from the device's longitudinal axis.At the same time, the bottom wall is not too wide, which would increase the flow resistance.

[0052] It may also be advantageous for at least one side wall to have, at least in sections, an acute interior angle to the connecting wall, and preferably an interior angle to the connecting wall of between 60° and 89°, particularly preferably between 60° and 80°. Such a section is particularly advantageous in the region of the side wall further away from the connecting wall, preferably at the lower end of the side wall.

[0053] Furthermore, it can be provided that the distance between the side walls increases, at least in sections, with increasing distance from the connecting wall. This results in a widening of the cross-section toward the bottom wall. This allows for a larger mass flow and a greater force due to the flow deflection.

[0054] It can also be provided that the distance between the side walls decreases, at least in sections, with increasing distance from the connecting wall. This is particularly advantageous in the area of ​​the floor wall.

[0055] It can be provided that at least one edge between at least one side wall and the base wall and / or the connecting wall is sharp-edged. This clearly defines the height of the side walls. It can also be provided that at least one such edge is rounded and / or curved. In this case, it is usually advantageous if the apex in the cross-section is considered the corresponding end of the side wall or the other wall.

[0056] In order to provide a sufficiently long flow channel, it can be provided that at least one of the side walls has a length-to-width ratio of greater than 1, preferably greater than 1.5.

[0057] It can be provided that the connecting wall defines a connecting plane, and that the lower end of one side wall is closer to the connecting plane than the lower end of the other side wall. In a flow body, it is particularly advantageous if the side wall of the lower end, which is closer to the connecting plane, is arranged closer to the device's longitudinal axis than the other side wall. Preferably, one lower end is between 5° further away from the connecting plane than the other lower end.

[0058] Preferably, at least one side wall has a transition radius to the bottom wall in cross-section. If the radius is selected to be larger, a transition from the side wall to the bottom wall may occur. A transition radius is the radius of the transition area between the side wall and the bottom wall. Alternatively, at least one transition between at least one side wall and the bottom wall can be angular.

[0059] It can also be advantageous to connect the lower end of one sidewall—preferably the sidewall whose lower end is further from the connecting plane—to the bottom wall via a smaller transition radius than the lower end of the other sidewall. This creates a sharper edge on the straighter wing. A larger radius makes it easier for the airflow to flow around this radius. The leading edges sink.

[0060] For the guidance of the flow, it can be advantageous if the cross section of the flow channel is asymmetrical, at least in sections, at least along a vertical axis of the fin.

[0061] In order to achieve a particularly stable and cost-effective embodiment, it can be provided that the connecting wall, the side walls and the bottom wall are in one piece and are preferably manufactured additively.

[0062] It can be provided that the bottom wall has at least one wall section which is at an angle to the connecting wall.

[0063] Furthermore, the floor wall can have at least two wall sections that are at different angles to the connecting wall. Preferably, the wall sections extend substantially along the entire length of the floor wall.

[0064] The invention also relates to a water flow body, in particular a water sports device, such as a surfboard or a kite surfboard, with an immersion surface for at least partial immersion during intended use in water, wherein at least one fin according to the invention is arranged on the immersion surface and the longitudinal axis of the fin is preferably arranged parallel to a device longitudinal axis of the immersion surface. In this way, the flow along the immersion surface can be stabilized and a more stable ride can be achieved. The term flow body here means a body with a flow surface, wherein the flow body is designed to move in a fluid flow, preferably air or water flow. Flow bodies include, for example, vehicles, in particular aircraft or watercraft.

[0065] Preferably, the longitudinal axis of at least one fin is at an angle other than 0° to the device's longitudinal axis. This angle is preferably less than + / - 10°, particularly preferably less than + / - 5°, and most preferably less than + / - 3°. Preferably, the end of the fin that is closer to the device's transverse axis points toward the device's longitudinal axis. This enables improved flow, especially when the device is positioned at an angle in the flow.

[0066] Furthermore, it can be provided that two fins, which are arranged on opposite sides of the device's longitudinal axis and preferably arranged substantially at the same height along the device's longitudinal axis, each have longitudinal axes that are at an angle other than 0° to each other. This angle is preferably less than + / - 10°, particularly preferably less than + / - 5°, and most particularly preferably less than + / - 3°. Preferably, the ends of the fins that are closer to the device's transverse or latitudinal axis point toward the device's longitudinal axis. This enables a so-called tow-in with improved flow behavior.

[0067] It can also be provided that two fins, which are arranged on opposite sides of the device's longitudinal axis and are preferably arranged substantially at the same height along the device's longitudinal axis, each have longitudinal axes which are at mirror-like angles or at different angles to the device's longitudinal axis.

[0068] Furthermore, it can be provided that the side wall whose leading edge area is offset further forward along the longitudinal axis than that of the other side wall is positioned further away from the device's longitudinal axis of the immersion surface than the other side wall. This ensures that, in the case of an oblique flow direction, the flow is not blocked by the opposite side surface.

[0069] It is also advantageous if at least two fins are arranged on the immersion surface, and that they are arranged at the same height along a longitudinal axis of the immersion surface and preferably mirror-symmetrically along the longitudinal axis of the device. This allows asymmetric effects on the flow of a single fin to be compensated.

[0070] Preferably, at least one fin is arranged in at least one corner region of the immersion surface, and fins are preferably arranged in at least two corner regions on opposite sides of the device's longitudinal axis, and particularly preferably in all corner regions of the immersion surface. Fins that are opposite one another along the device's longitudinal axis are very particularly preferably aligned mirror-symmetrically. This enables a comprehensive effect at different flow direction angles.

[0071] It is particularly advantageous if the fins, which are positioned opposite each other along a width axis of the immersion surface perpendicular to the longitudinal axis of the device, are arranged mirror-symmetrically. This allows asymmetric flows to be compensated.

[0072] The invention will now be explained using non-limiting embodiments of the invention. They show:

[0073] Fig. 1a is an oblique view of a fin according to the invention in a first embodiment;

[0074] Fig. lb is a plan view of the first embodiment;

[0075] Fig. 2a is an oblique view of a fin according to the invention in a second embodiment;

[0076] Fig. 2b is a bottom view of the second embodiment;

[0077] Fig. 2c shows a cross-section of the second embodiment normal to the longitudinal axis;

[0078] Fig. 2d is a side view of the second embodiment;

[0079] Fig. 3a is an oblique view of a fin according to the invention in a third embodiment;

[0080] Fig. 3b is a bottom view of the third embodiment;

[0081] Fig. 3c shows a cross-section of the third embodiment normal to the longitudinal axis;

[0082] Fig. 3d is a side view of the third embodiment;

[0083] Fig. 4a is an oblique view of a fin according to the invention in a fourth embodiment;

[0084] Fig. 4b is a bottom view of the fourth embodiment;

[0085] Fig. 4c shows a cross-section of the fourth embodiment normal to the longitudinal axis;

[0086] Fig. 4d is a side view of the fourth embodiment; Fig. 5a is an oblique view of a fin according to the invention in an embodiment;

[0087] Fig. 5b shows a cross-section of the fifth embodiment normal to the longitudinal axis;

[0088] Fig. 6a is an oblique view of a fin according to the invention in a sixth embodiment;

[0089] Fig. 6b is a bottom view of the sixth embodiment;

[0090] Fig. 6c shows a cross-section of the sixth embodiment normal to the longitudinal axis;

[0091] Fig. 7a is an oblique view of a fin according to the invention in a seventh embodiment;

[0092] Fig. 7b is a bottom view of the seventh embodiment;

[0093] Fig. 7c shows a cross-section of the seventh embodiment normal to the longitudinal axis;

[0094] Fig. 7d is a side view of the seventh embodiment;

[0095] Fig. 8a is an oblique view of a fin according to the invention in an eighth embodiment;

[0096] Fig. 8b is a bottom view of the eighth embodiment;

[0097] Fig. 8c shows a cross-section of the eighth embodiment normal to the longitudinal axis;

[0098] Fig. 9a is an oblique view of a fin according to the invention in a ninth embodiment;

[0099] Fig. 9b is a side view of the ninth embodiment;

[0100] Fig. 9c shows a cross-section of the ninth embodiment normal to the longitudinal axis;

[0101] Fig. 10a is an oblique view of a fin according to the invention in a tenth embodiment;

[0102] Fig. 10b is a bottom view of the tenth embodiment; Fig. 10c is a cross-sectional view of the tenth embodiment normal axis;

[0103] Fig. 10d is a side view of the tenth embodiment;

[0104] Fig. 11a is an oblique view of a fin according to the invention in an eleventh embodiment;

[0105] Fig. 11b shows a cross-section of the eleventh embodiment normal to the longitudinal axis;

[0106] Fig. 12a is a bottom view of an embodiment of a water flow body according to the invention in the form of a kite surfboard;

[0107] Fig. 12b is a side view of the embodiment of Fig. 12a;

[0108] Fig. 12c is a front view of the embodiment of Figs. 12a and 12b;

[0109] Fig. 13 is a bottom view of an embodiment of a water flow body in the form of a kitesurfing board according to the invention in an alternative embodiment.

[0110] The embodiments shown have two side walls 2a, 2b, each connected at an upper end 2g to a connecting wall 1 and at a lower end 2h to a bottom wall 3. This results in a flow channel 4 defined by these walls and having a first opening 5 and a second opening 6. The upper ends 2g of the side walls are spaced apart from one another. The lower ends 2h are also spaced apart from one another.

[0111] The connecting wall 1 is designed as a continuous wall which, in particular in the first ten embodiments, extends from one side wall 2a to the other side wall 2b.

[0112] The connecting wall 1 defines a connecting plane E, along which the fin, in the connected state, is connected to a component such as a water sports device.

[0113] The connecting wall 1 has two connecting areas 1a in the form of openings. Screws or other connecting means can be passed through these openings, thus attaching the connecting wall 1 to a flow body such as a water sports device. In the first embodiment, the connecting areas 1a are arranged asymmetrically with respect to the longitudinal axis L of the flow channel 4. In the second to eleventh embodiments, they are arranged symmetrically with respect to the longitudinal axis L.

[0114] In the area of ​​the first opening 5, the side walls 2a, 2b have leading edge regions 2c, 2d, which are arranged at different heights along the longitudinal axis L. This results in an offset V along the longitudinal axis L.

[0115] Both side walls 2a, 2b of the second embodiment are at an obtuse interior angle to the connecting wall 1, with their height and interior angle being equal. This results in a depth extension T that is equal for both side walls 2a, 2b. Due to the obtuse interior angle, the height of the side walls 2a, 2b is greater than their depth extension T.

[0116] In the first embodiment, the side walls 2a, 2b are parallel to each other and they also extend parallel to a vertical axis H. This results in a consistently large cross-sectional area of ​​the flow channel 4.

[0117] In the second, third, fourth, and seventh embodiments, the side walls 2a, 2b form an interior angle A of approximately 105° to the connecting wall 1 and / or the connecting surface 1a in cross-section. Thus, the distance between the side walls 2a, 2b widens along the vertical axis H toward the bottom wall 3a, 3b.

[0118] In the fifth, ninth, and tenth embodiments, a side wall 2b has two wall segments arranged one behind the other along the vertical axis H. One wall segment, preferably the wall segment closer to the connecting wall 1, has an interior angle A' (approximately 120° in the fifth embodiment) with the connecting wall 1. The other wall segment, preferably the wall segment closer to the bottom wall 3, has an interior angle A" (approximately 75° in the fifth embodiment) with the connecting wall 1. In the fifth and tenth embodiments, this is the side wall 2b, which is offset further back along the longitudinal axis L, and in the ninth, it is the side wall 2a, which is offset further forward.

[0119] In the sixth embodiment, the side walls 2a, 2b are parallel to each other, but are at an angle of approximately 80° or 100° internal angle to the connecting wall.

[0120] In the eighth embodiment, the side walls 2a, 2b are curved along their height along the vertical axis H. Fig. 9c shows that the ninth embodiment has a connecting wall 1 that is flat in the W direction and has a connecting surface 1b on the side facing the flow channel. This surface lies on a connecting plane E.

[0121] The first embodiment has leading edge regions 2c, 2d which are parallel to the vertical axis H and normal to the connecting plane E.

[0122] In embodiments two to ten, the leading edge regions 2c, 2d are at an opening angle B to the vertical axis H and also to the connecting wall 1 that is not 90°. In the second embodiment, they have an opening angle B of approximately 45° to the connecting wall 1. In some embodiments, such as embodiment seven, at least one leading edge region 2c, 2d has various subregions with different opening angles B to the connecting wall 1 and / or to the vertical axis H. The smaller opening angle B and the relatively less inclined trailing edge regions 2e, 2f result in a tapering of the side walls 2a, 2b in the direction of the bottom wall 3, 3a, 3b. This is particularly visible in Fig. 2a for side wall 2b.

[0123] In embodiments eight and ten, the side wall 2a or 2b is curved.

[0124] A second side wall 2b of the first embodiment has, at every height along the vertical axis H, a significantly shorter length II along the longitudinal axis L than a length 12 of a first side wall 2a. The second side wall 2b extends along its entire length II at the height of the first side wall 2a along the longitudinal axis L.

[0125] In the second embodiment, the first side wall 2a has a substantially shorter length than the second side wall 2b.

[0126] Preferably, the second opening 6 is located in a plane perpendicular to the longitudinal axis L. This is the case, for example, in the first embodiment. There, the side walls have trailing edge regions 2e, 2f, which are also aligned parallel to the vertical axis H. They are arranged at the same height along the longitudinal axis L.

[0127] In other embodiments, for example the fourth, sixth, eighth or tenth, the trailing edge regions 2e, 2f also have an offset V'.

[0128] As shown in Fig. 2, when the fin is obliquely flowed by a fluid flow 7, more fluid, for example water or air, can flow into the flow channel 4 through the enlarged first opening 5 than into the cross section of the flow channel 4 normal to its longitudinal axis.

[0129] This leads to an acceleration of the flow in the flow channel 4, which also increases the outflow velocity from the second opening 6. This stabilizes the flight. At the same time, however, the cross-section of the flow channel 4 is not constricted, thus keeping the flow resistance low.

[0130] In the first, fifth and sixth embodiments, the bottom wall 3 is planar, i.e. flat.

[0131] In the second, third, and fourth embodiments, the bottom wall 3 has two wall sections 3a, 3b, which are at an angle of approximately 150° to each other. They extend evenly along the longitudinal axis. This creates a lower peak and increases the flow cross-section.

[0132] In some embodiments, such as design nine or eleven, the bottom wall is slightly curved in cross-section.

[0133] In some embodiments, such as embodiments five or eleven, the bottom wall 3 is at an angle to the connecting wall 1 and / or the connecting surface 1a.

[0134] Fig. 2b shows that both side walls 2a, 2b have asymmetrical profiles along their longitudinal axes. The leading edge regions 2c, 2d are designed as profile noses with profile radii. The trailing edge regions 2e, 2f are designed as trailing edges, which are preferably sharp-edged.

[0135] The third embodiment is very similar to the second embodiment. However, it differs in the size of the offset. While the offset V of the second embodiment accounts for approximately 25% of the total length of the fin, the offset V of the third embodiment is approximately 10%.

[0136] In the tenth embodiment, the lower end 2h of one side wall 2b is closer to the connecting plane E than the lower end 2h of the other side wall 2a. The lower lower end 2h has a smaller transition radius 8a than the transition radius 8b of the other lower end 2h.

[0137] The eleventh embodiment in Figs. 11a, 11b shows an embodiment in which the flow channel 4 is formed by the side walls 2a, 2b and the bottom wall 3, but not by the connecting wall 1. The side walls 2a, 2b are not spaced apart from each other at their upper ends, but converge. The connecting wall 1 is essentially formed by a connecting surface 1b, which lies outside the flow channel 4. The connection by means of screws or other connecting elements takes place along the F indicated by the dot-dashed line in Fig. 11b.

[0138] A side wall 2a of the eleventh embodiment has an interior angle of 90° to the connecting surface 1a. This side wall 2a tapers in cross-section toward the bottom wall 3. Thus, it is thicker in the area of ​​the connecting elements and achieves sufficient stability, while not unnecessarily increasing the flow resistance at the bottom.

[0139] The other side wall 2b has an interior angle of approximately 135° to the connecting surface 1a.

[0140] Figures 12a-12c show a water flow body according to the invention, designed as a kitesurfing board. The kitesurfing board has a board body 20, on the underside of which a diving surface 21 is arranged. At least one fin according to the invention, four in the embodiment shown, is arranged on the diving surface 21. Fins are shown in an embodiment similar to the eleventh embodiment.

[0141] At least one fin, preferably each fin as shown in the figures, is arranged in a corner region of the board body 20 and / or arranged such that the longitudinal axis L of the fin is aligned substantially parallel to a device longitudinal axis 22.

[0142] At least one fin, preferably each fin, has offset leading edge regions 2c, 2d, as previously discussed, wherein the leading edge regions 2c, 2d point in the direction of the width axis 23. In other words, the leading edge regions 2c, 2d point in the direction of the front edge 24, which is further away from the fin.

[0143] The side wall 2b of at least one fin, whose leading edge region 2c is offset further forward along the longitudinal axis L than that of the other side wall 2a, is arranged further away from the device's longitudinal axis 22 of the immersion surface 21. This preferably applies to all fins, as shown in the figures.

[0144] The side wall 2b of at least one fin, which has an obtuse interior angle of approximately 135°, is further away from the device's longitudinal axis 22 than the other side wall 2a. This preferably applies to all fins, as shown in the figures.

[0145] Two fins are arranged symmetrically mirrored along the device's longitudinal axis 22.

[0146] Two fins are arranged symmetrically and mirrored along the width axis 23. Fig. 13 shows an embodiment similar to that in Figs. 12a-12c, but only the essential differences are discussed here. Equivalent components have the same reference numerals. It can be seen that on one side of the width axis 23, the two fins are arranged at an angle to one another. The longitudinal axes L of the fins are each at an angle of approximately +3° to the device's longitudinal axis 22, with the end of the fin that is arranged closer to the width axis 23 pointing towards the device's longitudinal axis 22. This results in a so-called tow-in for these two fins.

[0147] The two opposite fins do not have such a tow-in, but it can be provided that they are also inclined inwards, preferably the corresponding angles are mirrored at least around the width axis 23.

Claims

P A T E N T A N S P R Ü C H E 1. Fin, in particular for a flow body such as a surfboard, wherein the fin has a connecting wall (1) for connection to the flow body, and at least two side walls (2a, 2b), wherein at least two of the side walls (2a, 2b) are each connected to the connecting wall (1) in the region of an upper end (2g) and are connected to one another via a bottom wall (3) in the region of a lower end (2h), and thus a flow channel (4) with a longitudinal axis (L) and with at least one first opening (5) and at least one second opening (6) is formed by the side walls, the bottom wall (3) and preferably also the connecting wall (1), characterized in that at least one side wall (2a, 2b) has a depth-to-length ratio of less than 1.5, and in that at least one side wall (2a, 2b) has, at least in sections, an obtuse interior angle (A) to the connecting wall (1) along its entire extent along the longitudinal axis.

2. Fin according to claim 1, characterized in that the side walls (2a, 2b) in the region of the first opening (5) have leading edge regions (2c, 2d) and that the leading edge regions (2c, 2d) of the two side walls (2a, 2b) are offset from one another along the longitudinal axis (L) of the flow channel (4), and that it is preferably provided that the side walls (2a, 2b) in the region of the second opening have trailing edge regions (2e, 2f) and the trailing edge regions (2e, 2f) of the two side walls (2a, 2b) are offset from one another along the longitudinal axis (L) of the flow channel (4).

3. Fin according to claim 1 or 2, characterized in that at least one side wall (2a, 2b), preferably both side walls (2a, 2b), have a preferably asymmetrical profile.

4. Fin according to one of claims 1 to 3, characterized in that the leading edge region (2c, 2d) of at least one side wall (2a, 2b) has an opening angle of less than 90° with respect to the connecting wall (1).

5. Fin according to one of claims 1 to 4, characterized in that the distance of the side walls (2a, 2b) to one another along the longitudinal axis (L) remains substantially the same at least in sections.

6. Fin according to one of claims 1 to 5, characterized in that a cross-sectional area of ​​the flow channel (4) along the longitudinal axis (L) remains substantially the same size.

7. Fin according to one of claims 1 to 6, characterized in that the upper end (2g) of at least one side wall (2a, 2b) and the lower end (2h) of the same side wall (2a, 2b) are arranged at least partially at the same height along the longitudinal axis (L).

8. Fin according to one of claims 1 to 7, characterized in that the side walls (2a, 2b) are arranged at least partially at the same height along the longitudinal axis (L) and / or that the side walls (2a, 2b) have lengths along the longitudinal axis (L) which are of different sizes.

9. Fin according to one of claims 1 to 8, characterized in that at least one side wall (2a, 2b) has, along its entire extension along the longitudinal axis, at least in sections, an internal angle (A) to the connecting wall (1) of between 100° and 140°.

10. Fin according to one of claims 1 to 9, characterized in that at least one side wall (2a, 2b) has, at least in sections, an acute internal angle (A) to the connecting wall (1) and preferably has an internal angle (A) to the connecting wall (1) between 60° and 80°.

11. Fin according to one of claims 1 to 10, characterized in that the distance of the side walls (2a, 2b) to one another increases, at least in sections, with increasing distance from the connecting wall (1).

12. Fin according to one of claims 1 to 11, characterized in that the distance of the side walls (2a, 2b) to one another decreases at least in sections with increasing distance from the connecting wall (1).

13. Fin according to one of claims 1 to 12, characterized in that the connecting wall (1) defines a connecting plane (E) and that the lower end of one side wall (2a, 2b) is closer to the connecting plane (E) than the lower end (2h) of the other side wall (2a, 2b).

14. Fin according to one of claims 1 to 13, characterized in that the lower end (2h) of a side wall (2a, 2b) - preferably the side wall (2a, 2b) whose lower end (2h) is further from the connecting plane (E) - is connected to the bottom wall (3) via a smaller transition radius (8a, 8b) than the lower end (2h) of the other side wall (2a, 2b).

15. Fin according to one of claims 1 to 14, characterized in that the cross section of the flow channel (4) is asymmetrical at least in sections at least along a vertical axis (H) of the fin.

16. Fin according to one of claims 1 to 15, characterized in that the connecting wall (1), the side walls (2a, 2b) and the bow wing (5) are in one piece and are preferably manufactured additively.

17. Fin according to one of claims 1 to 16, characterized in that the bottom wall (3) has at least one wall section (3a) which is at an angle to the connecting wall (1).

18. Water flow body, in particular water sports equipment, such as a surfboard or a kite surfboard, with an immersion surface (21) for at least partial immersion during intended use in the water, characterized in that at least one fin according to one of the preceding claims is arranged on the immersion surface (21) and that the longitudinal axis (L) of the fin is preferably arranged parallel to a device longitudinal axis (22) of the immersion surface (21).

19. Water flow body according to claim 18, characterized in that the side wall (2a, 2b) which is arranged further away from the device longitudinal axis (22) of the immersion surface (21) than the other side wall (2a, 2b) has, at least in sections, an obtuse internal angle (A) to the connecting wall (1) along its entire extent along the longitudinal axis (L).

20. Water flow body according to claim 18 or 19, characterized in that the side wall (2a, 2b) whose front edge region (2c, 2d) is offset further forward along the longitudinal axis (L) than that of the other side wall (2a, 2b) is arranged further away from the device longitudinal axis (22) of the immersion surface (21) than the other side wall (2a, 2b).

21. Water flow body according to claim 18 or 19, characterized in that at least two fins are arranged on the immersion surface (21) and that they are arranged along a device longitudinal axis (22) of the immersion surface (21) at the same height and preferably mirror-symmetrically along the device longitudinal axis (22).

22. Water flow body according to one of claims 18 to 21, characterized in that at least one fin is arranged in at least one corner region of the immersion surface (21) and fins are preferably arranged at at least two corner regions on opposite sides of the device longitudinal axis (22) and particularly preferably at all corner regions of the immersion surface (21), and that very particularly preferably fins which are opposite one another along the device longitudinal axis (22) are aligned mirror-symmetrically.

23. Water flow body according to one of claims 18 to 22, d characterized in that fins which are opposite one another along a width axis (23) of the immersion surface (21) which is normal to the overlying longitudinal axis (22) are arranged mirror-symmetrically. 2025 04 10 MT / MT

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