EP0088430B1 - Fin for a windsurf board - Google Patents

Description

The invention relates to a fin for a windsurf board, which is pivotally mounted about an axis in a fin box connected to the windsurf board, the pivot position being ascertainable in various intermediate positions by a resilient latching device, and the pivot point of the fin being arranged in the fin box which is open at the bottom is.

A fin of this type was proposed for the first time for windsurfing according to an earlier proposal by the applicant (DE-U 7732145). In this known fin, which is generally referred to as a folding fin, the aim is to make it possible to adjust the fin with regard to the different speeds at which fins of different lengths would be optimal. Furthermore, by folding down the known fin, the possibilities of injury during handling and damage to the fin during base runs are to be avoided.

However, the applicant's earlier proposal of a fin of the type defined in the introduction has the disadvantage that even the folded-down fin still protrudes considerably beyond the underside of the windsurfing board.

In addition, in the development of windsurfing, especially with so-called fun and diving boards, extremely rigid and sharp-edged fins were developed for reasons of aquadynamic efficiency, which have a strong inclination or lengthening to the rear to lengthen the relatively short-form windsurfing boards of this type. This is to extend the flow line of the short boards. In many cases, such fins with their rearward inclined region even protrude beyond the rear edge of the board. It has now been shown that these fins pose a considerable risk of injury (cf. Windsurfing Journal No. 2, February 1982, pages 50/51 "Killer fin"), which can even lead to deep flesh wounds.

The invention has for its object to provide a fin of the type specified above, which when a selectable load, be it from ground contact or body contact, detaches itself from the fin box and therefore no longer presents any risk of injury or damage.

This object is essentially achieved in a fin of the type specified above in that the axis is formed by two axle stubs projecting laterally from the fin, and in that each axle stub is held in the fin box by a releasable coupling device which, when one or both end positions are exceeded Axle stub releases.

It is obvious that the separation of fin and fin box, which is guaranteed in the construction proposed according to the invention, avoids any risk of injury to the user and, at the same time, any risk of damage to the fin under selectable circumstances.

In a preferred embodiment according to the invention, a coupling device is formed by a spring element, which is mounted in the fin box, the spring element holding the stub shaft with partial positive locking. This embodiment is particularly robust and simple, the force exerted on the stub axle being overcome to pull out or separate the fin from the fin box.

In particular, the invention can be further developed in that the spring element is T-shaped with a cross piece and a foot directed downwards, the cross piece being mounted in front of and behind the stub axle in the fin box, that the foot has a slot open at the bottom and a has the stub receiving bore in connection with the slot, and that the slot forms two legs of the foot, the springs of which releases the stub from the bore. This embodiment of the spring element represents a simple and reliable form of coupling device which holds the fin securely under normal stresses and yet ensures that the axle stub can be released from its bearing when such stresses are exceeded.

In order to enable easy reinstallation of the fin after such a violent separation, it is advantageous for the slots in the spring elements to be flared or funnel-shaped.

In a particularly preferred embodiment according to the invention, the ends of the crossbar are held biased by additional spring elements against an upper wall of a bearing recess in the sword case. This ensures a smooth triggering of the coupling device and, at the same time, advantageously enables the fin to be latched into its various positions, as explained below. The spring elements can be coil springs, disc springs, rubber pads or the like.

In this case, it is preferred to provide a device for adjusting the spring force of the spring elements exerted on the crosspiece. In particular, this device can be designed as adjustable screws in threads in the fin box, the ends of which engage with the spring elements. For reasons of strength, the threads are made of metal. This embodiment offers the advantage that the latching of the fin in the selected position can be set correspondingly hard in accordance with the present driving conditions or expected loads.

The spring element described can preferably be embodied as a plastic part, in which case a to improve the suspension properties above the bore for the stub axles is provided with a continuation of the slot in connection relief opening.

Likewise, rounded relief notches can be provided at the transition between the crosspiece and the foot part. This configuration of the T-shaped spring element improves its suspension properties and at the same time prevents damage to the spring element itself. In addition, this configuration allows spring elements of sufficient width to be used with the necessary spring properties in order to ensure secure mounting of the stub axles.

In a particularly preferred embodiment according to the invention, securing clips are provided on the spring elements or T-pieces, which hold the T-pieces in the bearing recesses.

This embodiment can be further developed in detail in that the securing brackets consist of a spring steel wire with a round cross section. Specifically, the safety brackets consist essentially of U-shaped pieces with two legs and a connecting section, the two legs abutting the legs of the foot of the T-piece and the connecting section is cranked to the side and runs parallel to the crossbar at the top of the foot . In this embodiment, the additional advantage is achieved that the spring force exerted on the stub axle of the T-piece can be significantly higher than is possible with a plastic part. This ensures with the simplest design that the fin is only triggered when it really encounters a serious obstacle.

In order to facilitate the insertion of the fin into the spring elements, it is preferred to design the securing bracket with respect to the fin to be pivotable laterally around the connecting section between an open and a closed position. In the open position, therefore, only the spring force of the spring element, which is preferably made of a plastic part, has to be overcome, while in the closed position, a much higher spring force is exerted on the stub axles. A particularly simple embodiment of the invention can be created in that the legs of the securing bracket have a bend in the plane parallel to the fin, the angle of which is such that the section lying below the bend in the closed position of the securing bracket rests parallel to the side of the fin . Furthermore, it is preferred to provide the securing bracket with a catch section for the stub axles, the catch section being designed as a hook-shaped extension of one of the legs which protrudes beyond the underside of the fin box. In this way it is achieved that, for example, when the ground comes into contact, the fin is only partially released from the fin box and is then moved out of the safety brackets when the pressure increases. At the same time, the hook-shaped extension serves as a handle for pivoting the safety bracket in the lateral direction.

To insert the fin, the free end of the extension is at a greater distance from the underside of the fin box than it corresponds to the diameter of the stub axle.

With increasing pressure on the fin after the stub axles have moved into the catching section, the round cross section of the securing bracket is brought into the open position as a cam surface for pivoting the securing bracket, so that when this pressure is overcome the fin is completely released from the fin box.

In the case of the fin according to the invention, it is particularly preferred to connect the fin to the fin box by means of a lanyard so that it is not lost when overloaded. In particular, it is preferred for this purpose to use a round rubber which is fastened in the region of the front edge of the section of the fin accommodated by the fin box and is guided through a bore in the fin to the rear edge of the section.

From the hole, the safety line should preferably be routed along one of the rear edges of the fin section to an anchor in the area of the lower edge of the fin box.

This configuration, in particular in connection with a round rubber as a safety line, allows the fin itself to be held simultaneously with a slight pretension with regard to a pivoting movement, so that the selected pivoting position of the fin is reliably maintained.

In a particularly preferred embodiment according to the invention, the section of the fin accommodated by the fin box is designed with an approximately semicircular upper edge and with at least one rounded hump on the upper edge, which can optionally be brought into engagement with corresponding humps in the upper wall of the fin box. This configuration allows the fin to be securely locked in the selected position, which is possible without additional locking means or spring means due to the resilient configuration of the coupling devices.

In this embodiment, it is preferred that two bumps on the fin receive a bump of the fin box between them in the locked position.

Furthermore, it is preferred to make the flanks of the first and last peaks of the fin box facing the fin flatter than the other cusps. This makes it easier to trigger the fin.

In a particularly preferred embodiment according to the invention, a locking device is additionally provided for the spring elements, which rigidly presses the transverse web of the T-piece 21 against the upper wall of the bearing recess. This embodiment ensures that the fin does not accidentally ver is set and still a safe triggering of the fin is ensured when hitting an obstacle.

The locking device can be designed in detail by locking screws that can be screwed into the fin box. The locking screws can be screwed into the threaded inserts of the fin box instead of the set screws.

A particularly preferred development of the invention can be created in that the set screws are designed as hollow screws with an internal thread and the locking screws engage in the internal thread. This embodiment makes it possible to choose both modes of operation of the fin in a compact design.

An advantageous development of the invention can be created in that the above-mentioned anchoring is designed as an elastic stop for the rear edge of the fin.

It is preferred here to fasten the anchoring to the fin box by means of a screw, which at the same time holds a cable lug or the like fastened to the rubber cord as a holder on the fin box.

• Fig. 1 eine seitliche, teilweise aufgebrochene Schnittansicht des von einem Finnenkasten aufgenommenen Kopfteils einer Finne nach der Erfindung in etwa natürlicher Grösse;
• Fig. 2 eine verkleinerte Schnittansicht des Finnenkastens;
• Fig. 3 eine Draufsicht auf den Finnenkasten gemäss Fig. 2;
• Fig. 4 eine Schnittansicht des Oberteiles der Finne in verkleinertem Massstab in der Ebene der Schwenkachse;
• Fig. 5 eine Seitenansicht der Finne;
• Fig. 6 eine Schnittansicht der Finne gemäss Fig. 5 in der Ebene Vl;
• Fig. 7 eine Schnittansicht in der Ebene VII der Finne gemäss Fig. 5;
• Fig. 8 eine Ansicht in Richtung des Pfeiles VIII von Fig. 5;
• Fig. 9 eine besonders bevorzugte Ausführungsform nach der Erfindung in einer seitlichen, teilweise aufgebrochenen Schnittansicht, wobei die Darstellung der Darstellung gemäss Fig. 1 entspricht und einige Einzelteile in auseinandergezogener Darstellung wiedergegeben sind;
• Fig. 10 eine Fig. 4 entsprechende Schnittansicht der Ausführungsform gemäss Fig. 9 in vergrösserter Darstellung und
• Fig. 11 eine Schnittdarstellung einer Einzelheit einer besonders bevorzugten Ausführungsform der Stellschraubeneinrichtung.

The invention is explained in more detail below on the basis of exemplary embodiments illustrated in the drawings. It shows:

• Figure 1 is a side, partially broken sectional view of the head part of a fin according to the invention, accommodated by a fin box, of approximately natural size;
• Figure 2 is a reduced sectional view of the fin box.
• 3 shows a plan view of the fin box according to FIG. 2;
• Figure 4 is a sectional view of the upper part of the fin on a reduced scale in the plane of the pivot axis.
• Fig. 5 is a side view of the fin;
• 6 shows a sectional view of the fin according to FIG. 5 in the plane VI;
• FIG. 7 shows a sectional view in plane VII of the fin according to FIG. 5;
• Fig. 8 is a view in the direction of arrow VIII of Fig. 5;
• 9 shows a particularly preferred embodiment according to the invention in a lateral, partially broken-away sectional view, the representation corresponding to the representation according to FIG. 1 and some individual parts being shown in an exploded view;
• FIG. 10 shows a sectional view corresponding to FIG. 4 of the embodiment according to FIG. 9 on an enlarged scale and
• 11 is a sectional view of a detail of a particularly preferred embodiment of the set screw device.

In the embodiment according to the invention illustrated by way of example in the drawings, a sectional illustration of a fin box 2 recessed into the windsurfing board 1 is illustrated in FIG. 1 approximately in natural size in the rear region of a windsurfing board 1. FIG. 1 shows here only the section of the fin 3 which is received by the fin box 2 and which is shown in more detail in FIG. 5. The head section 4 of the fin 3 illustrated in FIG. 1 is essentially semicircular and has two bumps 5, 6 in its upper edge. The bumps protrude beyond the radius of the semicircular section 4.

In the associated center of the semicircular section 4 of the fin 3, as illustrated in FIG. 8, two stub axles 7, 8 are provided on the fin 3, which can also be formed as a continuous axis in a bore in the fin 3.

In the partially broken sectional view according to FIG. 1, only the stub axle 7 lying at the rear with respect to the plane of the fin 3 shown is visible.

As can also be seen from FIG. 1, in the sectional view the top wall 9 is in a region which corresponds to the region within which the fin 3 can be adjusted in different positions, with corresponding inward bumps 9, 10, 11, 12, 13 , 14, between which recesses 15, 16, 17, 18, 19 are formed, in which the bumps 5, 6 can engage in a form-fitting manner in the different positions of the fin 3.

As shown in the example of the stub axle 7 in FIG. 1, the stub axles 7 and 8 are held on both sides of the fin 3 in a coupling device, generally designated 20, in the fin box 2. The coupling device 20 serves to make it possible to move the fin 3 completely out of the fin box 2, should a force act upon the fin 3 when it comes into contact with the ground or when it falls, which tries to push the bumps 5 and 6 in the upper edge of the section 4 to move beyond one of the end positions, as defined by the recess 15 or 19 in the top wall 9 of the fin box 2.

In the illustrated embodiment, a coupling device 20 consists of a spring element 21, which is T-shaped with a transverse web 22 and a downward foot 23.

The spring element is mounted in the bearing recesses 24 provided on both sides of the fin 3 in the fin box 2 by the crossbar 22 being pressed against an upper wall 27 of the bearing recess by further spring elements 25, 26.

As sketched in Fig. 1, the further spring elements 25, 26 can be designed either as a coil spring or as a rubber cushion.

To accommodate the stub axles 7 and 8, each spring element 21 has a bore 28 which is connected to a slot 29 at the top and bottom. Ends above the bore 28 the slot 29 in a comparatively large relief bore 30. Below the bore 28, the slot 29 is flared or funnel-shaped.

At the transition of the foot 23 to the crossbar 22, relief notches 31, 32 are provided on both sides of the spring element. It is obvious that this shape of the spring element, similar to a clothespin, enables the legs 33, 34 formed on both sides of the slot 29 to be moved apart in a spring-like manner, in which case the stub axle 7 or 8 can be moved out of the bore 28. Apart from the material used, which is preferably a plastic, the suspension properties of the spring element 21 can be determined by appropriate design of the relief opening 30 or relief notches 31, 32.

As can be seen in particular from FIGS. 3 and 4, the mounting recesses for the spring elements 21 are provided in side housings 35, 36 of the fin box 2. 1 shows that the opening 38 of the bearing recess 24 leading to the underside 37 of the fin box 2 and thus to the bottom surface of the windsurfing board 1 is also funnel-shaped or conically widening downwards in order to enable the legs 33 and 34 to spring open.

Since the fin 3 detaches itself from the coupling device 20 from the fin box 2 when the axle stub 7, 8 is torn out, in the preferred embodiment, as shown in FIG. 1, a safety line 38 is also provided, which connects the fin 3 to the fin box 2. In the exemplary embodiment, the safety line 38 is formed by a round rubber 39 which has an anchoring 41 in the region of the front edge 40 of the head section 4 of the fin 3. The round rubber 39 is guided from the anchoring 41, which is arranged in a recess 43 in the front edge 40, through a bore 42 to the rear edge 44 of the head section 4. In order to facilitate threading, an opening 45 is also provided in the head section 4, which also serves to save the weight of the fin 3. From the exit end of the bore 42 in the rear edge 44 of the head section 4, the round rubber is guided downward in an open groove 46 and fastened to the lower edge of the fin box 2 in an anchorage, generally designated 47. The described guidance of the safety line 38 serves, on the one hand, to enable the various positions of the fin 3 in the fin box 2 by means of elasticity without hindrance and, on the other hand, to hold the fin with sufficient play when the fin is torn out, so that it no longer offers any risk of injury.

FIG. 2 shows the fin box 2 in a lateral sectional view that is reduced compared to FIG. 1. As shown, the top wall 9 of the fin box 2 has a substantially semicircular shape, a rear wall section 48 having a radius which corresponds to the radius of the rear edge 44 corresponds to the head section 4. Furthermore, the tips of the inwardly directed cusps 10, 11, 12, 13 and 14 lie on this radius.

A front wall section 49 of the wall 9 lies on the radius of the base of the depressions 15 to 19 formed between the bumps 10 to 14. This radius corresponds to the radius of a leading edge 50 (see FIG. 5) of the fin 3.

As further shown, the most forward bump 14 of the wall 9 is formed with a steep front flank, which forms a stop 51. When pivoting the fin 3 around the stub axle 7, in the most vertical position of the fin 3, a stop 52 engages with this stop, which through the transition edge from the radius of the rear edge 44 or front edge 40 of the head section 4 to the larger radius of the leading edge 50 is formed. This position represents the planned foremost or most vertical position of the fin 3 without triggering the coupling devices 20.

The most pivoted backward position of the fin 3 is illustrated in Fig. 1, in which the bumps 5, 6 sit in the recesses 18, 19. This position without triggering the coupling devices 20 is determined by striking the rear edge 53 against a stop 54 provided at the rear end of the fin box 2. In the exemplary embodiment, the stop 54 forms part of the anchoring 47 of the suspension line and is preferably formed from a hard rubber or the like, so that the trailing edge can strike the stop 54 without damage.

In the illustrated embodiment, the swivel range of the fin 3 with respect to the fin box 2 is 20 89 ° without triggering the coupling devices.

If a force is exerted on the fin by the running up of the windsurf board due to or, for example, when falling through the body of the athlete beyond the limits of the swivel range, which force can strike in any direction, either the mutual abutment of the stops 51, 52 or the contact of the rear edge 53 of the fin 3 on the stop 54 as a lever point about which the fin 3 is tilted, overcoming the holding force of the coupling device. Here, the stub axles 7, 8 are moved out of the bore 28 while the legs 33, 34 are widened, so that ultimately the fin 3 is torn out of the fin box 2 and is only held by the suspension line 38. There is no longer any risk of injury. To reinsert the fin 3, only the stub axles 7, 8 are inserted into the flared area of the slot 29 and moved back under pressure into the snap holder of the bore 28.

In this context, it should be noted that the coupling devices 20 also trigger on the fin 3 in the event of violent lateral impacts, in which case only one of the first Axle stub is moved down out of the coupling device.

From the above description, it is also evident that the additional spring elements 25, 26, which hold the spring element forming the clutch 20, provide a simple possibility of carrying out the adjustment of the fin 3 in the pivoting direction within the fin box 2. When the bumps 5, 6 are passed over the corresponding counter bumps of the upper wall 9, the spring element 21 or both spring elements 21 are briefly moved downward against the pressure of the spring elements 25, 26.

The particularly preferred embodiment according to FIGS. 9 to 11 is described below, the basic structure of which corresponds to the embodiment according to the description above, so that the same reference numerals have been used for the same parts.

Reference is first made to the illustration according to FIG. 9. In this embodiment, a device, generally designated 55, is provided in order to adjust the spring force of the helical springs 25, 26 exerted on the transverse web 22 of the spring element 21. In the illustrated embodiment, this device is designed as set screws 56, which can be screwed and unscrewed in metal inserts 57 in the fin box 2 in the direction of the crossbar. The free ends 58 of the set screws 56 are in engagement with the coil springs 25, 26, which sit with their opposite ends in recesses 59 in the crosspiece 22.

In the embodiment illustrated in FIG. 9, each of the spring elements or T-pieces 21 is assigned a securing bracket 60, the function of which will be discussed in more detail with reference to FIG. 10. In the preferred embodiment, the safety bracket 60 is formed from a spring steel wire with a round cross-section essentially U-shaped. The securing bracket has two legs 61, 62 and a connecting section 63 connecting them. The two legs 61, 62 rest on the legs 33, 34 of the foot 23 and thus reinforce the spring force exerted by the legs 33, 34 on the stub axles 7, 8 of the fin 3, so that they only exert considerable pressure from the T- Be moved out. The connecting section 63 of the securing bracket 60 is cranked laterally and lies at the upper end of the foot 23 parallel to the crosspiece 22.

As can be seen from the view according to FIG. 10, the securing brackets 60 are designed to pivot laterally with respect to the fin 3 around the bent portion of the connecting section 63 between an open and a closed position. Here, the legs 61, 62 have a bend 64 in the plane parallel to the fin 3, the angle of which is such that the section 65 of the legs 61, 62 lying below the bend 64 in the closed position of the securing bracket 60 parallel to the side of the fin 3 is present.

As can also be seen from FIG. 9, the securing brackets 60 are provided with a catch section, generally designated 66, for the stub axles 7, 8, which in the exemplary embodiment shown consists of a hook-shaped extension 67 of the leg 61. The hook-shaped extension 67 protrudes over the underside 37 of the fin box 2 and at the same time forms a handle for the pivoting movement of the securing bracket 60 illustrated in FIG. 10.

A distance is provided between the free end 68 of the hook-shaped extension 67 and the underside of the fin box 2, which is greater than the diameter of the stub axles 7 and 8. This allows the fin with its stub axles 7 and 8 into the area of the T-piece or spring element 21 are brought without the safety bracket 60 having to be pivoted into the open position.

If, for example, the fin 3 is moved out of the bearing while overcoming the spring force of the legs 33, 34 of the T-piece 21 and the spring force additionally exerted by the legs 61, 62, for example with light ground contact, the fin 3 is initially only partially triggered and held by the catch section 66 of the safety bracket. If the stress exerted on the fin 3 increases, the round cross section of the spring wire of the securing bracket 60 acts as a cam surface, so that the securing bracket is deflected laterally and the fin is completely detached from the fin box 2 and is only held on the windsurf board 1 by the rubber cord 38 becomes.

In order to reinsert the fin 3 into the fin box 2, the securing brackets 60 are then folded into the outwardly pivoted open position illustrated in FIG. 10, in which the legs 61, 62 do not have any additional spring force on the legs 33, 34 exercise. Consequently, when the fin 3 is inserted, only the substantially lower spring force of the legs 33, 34 has to be overcome.

As can also be seen from FIG. 9, in each of the desired pivot positions of the fin 3, the two bumps 5, 6 receive one of the bumps 10, 11, 12 or 13 between them. This results in the illustrated embodiment four pivot positions of the fin 3, which the user can choose according to the desired trim of the windsurf board 1. To facilitate triggering when hitting an obstacle, the flanks 69, 70 of the last hump 14 or the first hump 71 on the fin box 2 are flatter than the flanks of the other humps.

If one of the trim positions of the fin 3 has proven to be optimal, it is possible in the embodiment according to FIG. 9 to fix it by the spring elements 25, 26, wel che press the ends of the crossbar 22 against the upper wall 27 of the bearing recess 24 of the fin box 2, be put out of function. In the embodiment illustrated in FIG. 9, as a locking device generally designated 72 for this process, a pair of locking screws 73 is provided, which are used instead of the set screws 56 and the coil springs 25, 26 to hold the T-piece 21 by the Blocking screws 73 are screwed into the threaded inserts 57.

A particularly preferred embodiment of the locking device 72 is illustrated in an enlarged view in FIG. 11. Are the set screws 56 formed as hollow screws 75, which are provided with slots 76 for engagement with the screwdriver. As a result, the hollow screws 75 retain their function as set screws.

In this embodiment, the blocking screws 73 are dimensioned such that they can be screwed into an internal thread 77 provided in the hollow screws 75 and fit through the inside diameter of the coil springs 24 and 25, respectively.

In this embodiment, to block a selected position of the fin 3, it is therefore not necessary to remove the set screws 56 together with the coil springs 24, 25, but rather only subsequently screw the blocking screw into the internal thread of the hollow screws 75 until the end of the blocking screw is firmly in place the recess 59 of the cross bar 22 sits and presses it against the wall of the bearing recess 24.

In both embodiments of the locking device 72, the function of the T-piece 21 as a releasable coupling is fully retained.

9 shows a preferred embodiment of the anchor 47 for the rubber cord 38. In the preferred embodiment, the rubber cord 38 is provided at its end facing the anchoring 47 with a cable lug 79 or the like having a bore 78, the stop 54 for the trailing edge 53 of the fin 3 likewise being provided with a bore 80. The anchoring 47 is formed by a screw 81 which is passed through the bore 80 and the bore 78 into a threaded insert 82 made of metal provided in the fin box 2.

It is obvious that the described embodiment ensures two basic functional principles of the fin 3, namely the adjustable grid system and the system blocked in the selected pivot position. In both systems, four different fin positions are possible for reasons of trimming and for safety, and at the same time, a total triggering of the fin is guaranteed in the event of overuse.

In the adjustable system, the fin 3 folds back and forth due to the suspension in the event of unforeseen resistance, without jumping out of the T-piece 21. The fin 3 is only released from the bearing when the pressure does not drop.

In the system which locks a fixed setting, the spring mechanism is deactivated by the locking device 72, so that the fin jumps out of the bearing without any change in position and without any change in position.

In the illustrated embodiment, an easy assembly of the fin 3 is also possible if it should be carried separately for transport reasons, for example. For this purpose, the rubber cord 38 is first inserted into the groove 46 in the rear edge 44 of the head section 4 of the fin and the cable lug 79 located at the free end is threaded with its bore 78 onto the end of the screw 81, which previously passed through the bore 80 of the stop 54 has been. This arrangement is then screwed onto the fin box 2 by means of the screw 81 by screwing the screw 81 into the threaded insert 82. Then both safety clips 60 are pressed into the open, laterally pivoted-away position, and the fin 3 with its stub axles 7, 8 is pressed until it audibly snaps into place between the legs 33, 34 of the T-piece 21. Then both safety brackets 60 are pivoted into the closed position.

The selected pivot position of the fin 3 can then optionally be fixed using the locking device 72.

It is obvious that the various changes and modifications of the described embodiment will be familiar to the person skilled in the art without departing from the basic idea of the invention, which is seen in giving a fin of a windsurfing board with a possible possible adjustment which can be triggered to separate the fin from the board to avoid injury.

Claims (25)

1. A fin for a windsurfing board, which fin is mounted in a fin-box connected to the windsurfing board and is pivotally movable in said box between two end positions and adapted to be fixed in various angular positions by a resilient detent mechanism, the axle being disposed in the open-bottomed fin-box, characterized in that the axle (7, 8) is constituted by two stub axles (7, 8), which laterally protrude from the fin (3), and each stub axle (7, 8) is held in the fin-box (2) by a releasable coupling device (20), which releases the stub axles (7, 8) in response to a movement beyond one or each end position.

2. A fin according to claim 1, characterized in that a coupling device (20) is constituted by a spring element (21), which is movably mounted in the fin-box (2) and non-positively holds the stub axle (7, 8) and partly interengages therewith.

3. A fin according to claim 2, characterized in that the spring element (21) is T-shaped and comprises a crosspiece (22) and a depending stem (23), the crosspiece (22) is movably mounted in the fin-box (2) before and behind the stub axles (7, 8), the stem (23) has an open-bottomed slot (29) and a bore (28), which communicates with the slot, and the slot defines two legs (33, 34) of the stem (23), which legs are resiliently spreadable to release the stub axle (7 or 8) from the bore (28).

4. A fin according to claim 3, characterized in that the slot (29) flares downwardly below the bore (28) in conical or funnel shape.

5. A fin according to claim 3 or 4, characterized in that the ends of the crosspiece (22) are prestressed by additional spring elements (25, 26) against a top surface (27) defining a mounting recess (24) in the fin-box (2).

6. A fin according to claim 5, characterized by means (55) for adjusting the spring force exerted by the spring elements (25, 26) on the crosspiece (22).

7. A fin according to claim 6, characterized in that the means (55) consist of adjusting screws (56), which are adjustable in screw threads of the fin-box (2) and have ends (58) which interengage with the spring elements (25, 26), and the screw threads of the fin-box (2) are preferably formed by metal inserts (57).

8. A fin according to claims 5 to 7, characterized in that the spring elements (25, 26) consist of helical springs or rubber pads.

9. A fin according to any of the preceding claims, characterized in that the spring element (21) consist of a plastic element.

10. A fin according to claim 9, characterized in that the spring element (21) is formed above the bore (28) with a relief opening (30), which communicates with the slot (29).

11. A fin according to any of the preceding claims, characterized in that rounded relief indentations (31, 32) are provided at the transition between the crosspiece (22) and the stem (23).

12. A fin according to any of the preceding claims, characterized in that bent locking members (60) are provided at the spring elements or the T-shaped members (21) and retain the T-shaped members (21) in the mounting recesses (24) and the bent locking members (60) consist particularly of spring steel wire which is circular in cross-section.

13. A fin according to claim 12, characterized in that the bent locking members (60) are substantially U-shaped and comprise two legs (61, 62) and a connecting portion (63), the two legs (61, 62) engage the legs (33, 34) of the stem (23), the connecting portion (63) is formed with a lateral offset and at the top end of the stem (23) is parallel to the crosspiece (22), and the bent locking members (60) are pivotally movable relative to the fin (3) in a lateral direction about the connecting portion (63) between opened and closed positions.

14. A fin according to claim 13, characterized in that the legs (61, 62) of the bent locking members (60) have in the plane that is parallel to the fin (3) a bend (64) at such an angle that in the closed position of the bent locking members (60) that portion (65) which is disposed below the bend (64) is parallel to the fin (3) and in contact with the same on one side.

15. A fin according to any claims 12 to 14, characterized in that the bent locking members (60) have a portion (66) for receiving the stub axles (7, 8).

16. A fin according to claim 15, characterized in that the receiving portion (66) consists of a hook-shaped extension (67) of one of the legs (61 or 62), said extension protrudes beyond the underside (37) of the fin-box (2), and the distance from the free end (68) of the hook-shaped extension (67) to the underside (37) is larger than would correspond to the diameter of the stub axles (7, 8).

17. A fin according to claims 12 and 15 to 16, characterized in that the round cross-section of the bent locking members (60) provides a cam face for the pivotal movement of the bent locking members (60) to their open position.

18. A fin according to any of the preceding claims, characterized in that the fin (3) is connected to the fin-box (2) by a safety line (38), which consists particularly of a round rubber cord (39).

19. A fin according to claim 18, characterized in that the safety line (38) is secured adjacent to the forward edge (40) of the top portion (4) of the fin (3), which top portion (4) is accommodated in the fin-box (2), the safety line (38) extends through a bore (42) in the fin (3) to the rear edge of the top portion (4) and extends from the bore (42) in a groove formed in the rear edge (44) of the top portion (4) and extends as far as to anchoring means (47) provided adjacent to the rear lower edge of the fin-box (2).

20. A fin according to any of the preceding claims, characterized in that the top portion (4) of the fin (3) is accommodated in the fin-box (2) and has a substantially semicircular top edge provided with at least one rounded hump (5, 6), which is selectively engageable with corresponding humps (10 to 19) on the top wall (9) of the fin-box (2), and the two humps (5, 6) on the fin (3) receive between them one of the humps (10 to 13) on the fin-box (2).

21. A fin according to claim 20, characterized in that the lateral edge faces (69, 70) of the first and last humps (71, 14) are narrower than the lateral edge faces of the remaining humps (10 to 13).

22. A fin according to any of the preceding claims, characterized in that locking means (72) are provided for the spring elements (25, 26) and rigidly urge the crosspiece (22) of the T-shaped member (21) againstthetop surface of the mounting recess (24).

23. A fin according to claim 22, characterized in that the locking means (72) is constituted by blocking screws (73), which are adapted to be screwed through the fin-box (2) and into the screw-threaded inserts (57).

24. A fin according to claim 22, characterized in that the adjusting screws (56) consist of hollow screws (75) having female screw threads (77) and the blockings screws (73) are screwed into the female screw threads (77).

25. A fin according to any of claims 19 to 24, characterized in that the anchoring means (47) comprise a resilient stop (54) for engagement with the rear edge (53) of the fin (3), and said stop (54) is secured to the fin-box (2) by a screw (81), which serves also to hold to the fin-box (2) a thimble (79) or the like which is secured to the rubber cord (38) and serves as a retainer.

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