US20090253319A1

US20090253319A1 - Floating hydrodynamic fin system

Info

Publication number: US20090253319A1
Application number: US12/061,658
Authority: US
Inventors: Massimo Ferru
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-04-03
Filing date: 2008-04-03
Publication date: 2009-10-08

Abstract

Floating hydrodynamic fin system, useful for surfboard and windsurf, modifying its fin lift trim by a calibrate and controlled spring and an asymmetric shape of the fin-base that leaves a gap between said fin-base and the fin-box, allows the floating of the system rearward and/or forward. This happens by:

- 1) reducing the resistance of the water flow against the fin.
- 2) influencing the critical point of the board by the vector lift force displacement rearward in one or more critical times.
- 3) reducing the fin lift surface due to a part displacement of the fin into the fin-box.

Said system can also works by a limited and calibrated movement of a fin-box into another fin-box controlled by a spring calibrate device and by a suitable fin-box shape that leaves a gap between the inside and outside box allowing the floating of the system.

Description

FIELD OF INVENTION

This invention is related to water planning crafts, such as surf and windsurf, and the function of the fin lift to enhance planning, maneuverability and specific tacks.

BACKGROUND ART

Fins are generally described by different shapes and hardness and are made of several lengths, width and twist response: it may change relative to the size board, sea and wind conditions, specific requirements. Fins available in the market typically are done to be located into a fin-box in a fixed position and the fin lift trim typically carries on its function by the fin in a static position near the rear of the board, so the desire to enhance such function is an objective of surfboard and fin constructors. In the present invention the fin can float in a limited calibrate oscillation.

DETAILED DESCRIPTION OF THE INVENTION

The present invention discloses “floating hydrodynamic fin system” for windsurf and surf. The fin systems available in the market don't float because the fin is stopped in a fixed beforehand position under the board, near its rear.
In the present invention the fin can float in a limited calibrate oscillation toward the rear-board. This fin floating is due:

- a) to a particular spring calibrate device or any other device that achieves the same function;
- b) to an asymmetric shape of the base of the fin which leaves a gap between the fin-base and the fin-box.

The spring is calibrated to let float the fin when the board is starting in a manner to reduce the resistance of the water flow against the fin and to displace said fin in a better hydrodynamic position.
Such device is adjusted by one or more springs in a manner to leave when the force generated by the water flow is pushing.
Said spring is located in the screw that locks the fin to the board by its head, and by a nut and lock nut (or blind nut) into the fin-box, at the same time the screw allows the movement of the fin and the spring, after compression, will relax floating in hydrodynamic mode.
The spring setting of the floating Fin system is done in accordance with the different kind of windsurf, surf, sea and wind conditions, or/and specific requirements.
The floating fin system changes the lift trim by a displacement toward the rear-board. When the board is jumping out of the water (critical start planning) said displacement carries on its function by the following:

- 1) reduction of the resistance of the water flow against the fin.
- 2) influence of the critical point of the rear side of the board in the critical time by a temporary vector lift force rearward.
- 3) reduction of the fin lift surface due to a part of the fin hiding into the fin-box.

Due to these hydrodynamic advantages the board, by such floating can plane earlier, can maintain the planning for more time and distance and can plane earlier another one.
The floating of the fin lift trim enhances its hydrodynamic function in a better temporary rear position during the board planning phases and maneuvers. The fin lift surface can decrease because the force generated from the speed that pushes on the fin surface enhancing its lift function.
The fin can also float toward the front direction of the board giving more flexibility and better maneuverability to typical windsurf and surf such as freestyle, this is possible:

- a) by the pivot that hooks the fin to the board positioned in the middle of the base of said fin, the screws and the calibrate springs positioned in the extremities of the above mentioned base;
- b) by a special shape which leaves a gap between the fin-base and the fin-box, useful for the above mentioned floating fin system.

The setting of the calibrate spring system will be done in accordance with specific requirements and priority and to obtain different performance.

BEST MODE FOR CARRYING OUT THE INVENTION

The best mode to carrying out this invention is: by a common fin-box that floats into another fin-box and by a pivot locked to the last one said fin-box in a two possible options:

- a) fixing the pivot (for the lock into the fin box) in the front side of the fin-box and the calibrate springs, or any other device, in the back side between the two said fin-boxes. Said system is useful for the fin floating toward rear-board;
- b) fixing the pivot in the middle of the fin-box, that is inserted into the other fin-box, and the spring devices, or any other device, in the front and back side between the two said fin boxes. Said system allows the movement of the fin both rearward and forward.

In a) and b) options the floating fin-box is limited by a shutter or another device that restricts the box displacement into the other fin-box.
Said inside fin-box will be made in a manner to leave a gap between inside and outside fin-box.
Some or more of all details to realize or complete this invention may change but remaining into this patent dominion.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

In the detailed description which follows, reference will be made to the drawing of the following figures:

FIG. 1 is a side lateral view of the floating hydrodynamic fin system where the dark area of the fin (1) shows the before start lift trim, and the light area shows the during start lift trim displacement rearward (2). The fin-box (3) is positioned in the rear of the board.

FIG. 2 is a view of the fin lift trim (8) in its modifying toward the rear-board (4) by the compression of the spring (5) put in the screw (6). The fin is stopped by the pivot (7) into the front side of the fin box of the board.

FIG. 3 is an under back side of the board showing the initial position of the fin before the starting of the board (1).

FIG. 4 is an under back side of the board showing the floating of the fin (2) after the pushing of the water flow force.

FIG. 5 is a side lateral view of the fin floating system where the pivot (3) stops it in the front side of the fin-box of the board. Said fin system by the screw (4) into the spring (5) and by an asymmetric shape of the fin-base (6) leaves a space to the floating rearward.

FIG. 6 is a side lateral view of the fin floating system where the pivot (7) hooks it in the middle position of the fin-box of the board; Said fin system by the screws into the springs (8 and 9) and by a typical shape of the fin-base (10 and 11) leaves a gap between said fin-base and the fin-box useful for the floating system toward front and rear-board.

FIG. 7 is a view of the screw (6) into the spring (7) which allows the fin swinging and the blind nut (8) that locks the fin to the board.

FIG. 8 is a fin-box (3) inserted into another fin-box (4) locked by a pivot (1) and swinging by the springs (2) where corresponds the floating fin from the original start position (5) to the after start rearward position (6). Such fin-box movement is restricted by a shutter (7) or any other device. The shape of the inside box (3) is asymmetric and leaves a gap between the two boxes allowing the swinging.

FIG. 9 is a fin-box (4) inserted and locked by a pivot (1) into another fin-box (5) and swinging by the springs (2 and 3) where corresponds the fin (6) floating toward front (7) and rear-board (8). Such fin-box movement is restricted by a shutter (9 and 10) or any other device. The shape of the inside box (4) leaves a gap between the two boxes allowing the swinging of the fin-box.

FIG. 10 shows the fin lift trim floating toward the front (1) and the rear-board (2).

BRIEF SUMMARY OF THE INVENTION

Floating hydrodynamic fin system useful for water planning crafts, such as surf and windsurf, works by a fin floating in a manner to modify its lift trim by the following device: a particular spring calibrate device or any other device that achieves the same function, and by an asymmetric shape of the fin-base that leaves a gap between said fin-base and the fin-box.
Such device changes the lift trim floating toward the rear and/or the front, thus enhancing the early planning of the board and the next displacement of the lift trim toward rear/front improves the maneuverability by the factors:

- 1) reducing the resistance of the water flow, against the fin.
- 2) influencing the critical point of the board by the vector lift force displacement rearward in one or more critical times.
- 3) reducing the fin lift surface due to a part displacement of the fin into the fin-box.

By such factors the board can also maintain the planning for more time and distance and can earlier plane another one.

Claims

1) Floating Hydrodynamic Fin System useful for surf and windsurf is characterized by:

A fin box located near the rear of the surfboard,

A fin located within the fin box,

A spring device located in the rear between the fin and the fin box and composed of the following parts: a steering and calibrated spring located in a screw that hooks the fin to the board by its head and by a blind nut to the fin box,

Said Spring device appositely built in order to compress the spring itself when the speed causes a certain amount of resistance in the water, When, the pressure on the fin is reduced, the fin returns to its original position relaxing the spring,

A plurality of motions of the fin rearward and forward for enhancing early planning, maintenance of planning for more time and distance and maneuverability of the board.

2) Floating Hydrodynamic Fin System as claimed in claim 1) is further characterized by:

The timing of the fin lift displacement: When the hoard overtakes the critical speed, starting to plane, and it is getting ready for the maneuvers, the system lets move the fin lift trim for enhancing early planning and easier, maneuverability of the board.

3) Floating Hydrodynamic Fin System as claimed in claim 1) is further characterized by:

A fin box into another fin box controlled by one or more calibrate springs and by a suitable fin box shape which leaves a space between the inside and outside box allowing a limited and calibrated movement of the fin system, Said limited and controlled motion both rearward and forward happens simultaneously and automatically while changing the fluid resistance depending on the planning phases and maneuvers of the board.