DE29600900U1 - Flipper - Google Patents

Description

Oceanic Europe SrL, Pomezia / Italy

SWIM FIN

The invention relates to a swimming fin with higher efficiency.

Fins are already known from the state of the art which have a shoe part made of a relatively soft material, while the fin part is made of a material with greater rigidity. Such fins represent a significant advance compared to the designs that were common up to that point, but it is still difficult to achieve an appropriate elastic behavior of the fin part, as is necessary for effective propulsion.

Another disadvantage of commercially available fins is that they do not allow the fin part to behave in a way that is completely tailored to the swimmer’s muscular strength, since their surface is not optimized in relation to the swimmer’s muscular strength.

This means that swimmers with moderate or even less muscle strength than those for which the fin was designed may have to exert excessive effort and may be more likely to develop cramps.

The mechanical energy expended by the water sportsman is converted into hydrodynamic energy during swimming. Part of the energy expended is used as useful work to create buoyancy, and part is lost in the wake or consumed by the viscous friction forces. The strongest muscle group in humans is the quadriceps group in the front part of the thigh, while on the other hand the adductor muscle group in the back part is less developed; during swimming the quadriceps is mainly responsible for pedaling forward, while the adductor is the muscle used mainly for pedaling backward. Thus the quadriceps is the muscle that performs the most in transferring energy from the water sportsman to the water.

The present invention is therefore based on the object of developing a swimming fin with which it is possible to change its geometry during the kicking phase and the pull-on phase in such a way that the greater part of the energy expended with the fin in the kicking phase is transferred from the swimmer to the water, whereby the energy loss in the wake and as a result of friction is reduced.

This object is achieved according to the invention with a swimming fin of the type mentioned at the outset in that a rib is provided on the lower middle section of the fin part, which rib has such a thickness that it is greatest at the front end section of a shoe part and approaches zero shortly before the end region of the fin part, whereby the rib allows the stiffening of the fin part at the connection point between the shoe part and the fin part and allows unhindered bending of the end region of the fin part as well as the execution of movements for expanding and contracting the V-shape of the fin part.

The swimming fin according to the invention has a special V-shape, which makes it possible to achieve a more or less variable

Geometry and thus a variable surface, also depending on the muscle strength of the muscles used, so that the power and performance are always tailored to the muscle mass of the water sports enthusiast.

When you kick downwards, for which, as already mentioned, the quadriceps femoris muscle on the front of the thigh is opened up further and further, thus increasing the usable area and the thrust; when you pull up, for which, as already mentioned, the adductor is used, the V-shape of the fin narrows and reduces the resistance and thus also the wasted energy.

Part of the energy applied by the water sportsman to the fin is used, as explained in detail above, for an appropriate thrust work, while the remaining part is lost as energy in the wake or in friction, both phenomena that arise essentially as a result of the form drag, the frictional drag and the resistance of the wake. When designing a swimming fin according to the invention, particular attention was paid to designing the fin in such a way that a significant reduction in hydrodynamic drag can be achieved.

In order to reduce the form drag, the fin forming the subject of the invention has a cross-section of the main part which gradually changes significantly and the outer edges are rounded so that the flow remains in contact with the body without causing vortex formation until the trailing edge of the fin is reached, thereby achieving optimal results from the point of view of hydrodynamic penetration. In order to reduce the frictional drag, the surface of the fin is made extremely smooth so that there is a laminar flow over it, which is accompanied by low frictional drag. In order to reduce the wake drag, two lateral ribs have been formed which prevent the formation of two lateral main vortices.

and a central rib which reduces the formation of vortices at the trailing edge, thus achieving a low wake drag. To maintain the flow in one direction, radial ribs are provided in such a way that when the fin begins to move in a wave-like manner, the propulsive forces drive the flow towards the trailing edge, achieving a more effective expulsion of the fluid from the body. The ribs are of such a thickness that the fin gains rigidity, particularly at the connection with the shoe part, i.e. at the point where the water sportsman transfers the energy to the fin, but with absolute flexibility at the trailing edge; in this way, immersion in the flow is maintained along the entire surface and, as a result, a fin is obtained which functions optimally from a hydrodynamic point of view.

The invention has been described rather briefly so far; for better understanding, it is now described in more detail below with reference to the accompanying drawing, in which:

Fig. 1 shows a plan view of the fin according to the invention;

Fig. 2 is a side view of the same fin;

Fig. 3 is a sectional view;

Fig. 4 shows a crack in the underside of the fin; and

Fig. A to R each show a cross-section at different points of the fin.

From these figures, the swimming fin according to the invention, designated 1, can be seen, which is formed from a molded body with one end having a shoe part 2 that is open in the rear section and which, towards the opposite end, turns into a fin part

3, whereby the shoe part is made of soft material, which, in conjunction with the special design, makes it possible to cover the needs of consumers to a large extent with only two sizes. On the side of the shoe part, at points 4 and 5, the connections for attaching the strap are provided, which are higher than usual, so that the strap running in the upper heel area ensures a better fit and thus offers protection against a possible loss of the fin.

The fin part has a V-shape which, as can be seen from the attached figures, and in particular from the sectional views I to R, gradually becomes more and more pronounced, starting from a quasi-flat formation at the cross-sectional line closer to the end section of the shoe part 2 and reaching a strongly pronounced V-shape at the end of the fin part 3 with the section line R.

A rib 6 arranged in the lower central region of the fin part 3 has a considerable height near the end section of the shoe part towards the fin (see sectional view I) and gradually decreases until it ends shortly before the end of the fin (see sectional view Q). In the manner explained below, this rib together with the above-mentioned ribs provides increased stiffness of the fin at the shoe part, at the point where the energy is transmitted from the swimmer, while allowing unhindered bending of the end section of the fin and making it possible to carry out the movement explained above for expanding and contracting the V-shape of the fin.

On the upper part of the fin 3 there are two lateral ribs 7 and 8 which follow the outer profile of the fin 3 up to the cross-sectional line E, as well as two inner ribs 9 and 10 which start from the cross-sectional line I at the point where the shoe part 2 ends and continue up to the end of the fin 2.

The ribs 7, 8, 9 and 10 have a radial course along the surface of the fin 3 and contribute to the flow

medium in this direction, so that when the wave-like movement of the fin 3 caused by the swimmer begins, the propulsion forces push the flow towards the trailing edge, resulting in a jet of the ejected flow medium and thus an optimized propulsion force, which increases the efficiency of the fin. In particular, the two lateral ribs 7 and 8, together with the middle rib, prevent the formation of two lateral vortices and prevent the formation of vortices at the trailing edge.

Like the lower middle rib 6, the ribs 9 and 10 also have a strength or thickness that is greater near the connection between the fin 3 and the shoe part 2 and virtually disappears completely at the end of the fin, so that the fin retains its flexibility and the escaping flow medium adheres to the surface of the fin, thereby greatly reducing the formation of vortices, reducing friction and significantly increasing performance, among other things due to the fact that the surface of the fin is extremely smooth.

OCE 1/96 PMÜ-3/96

REFERENCE SIGNS

Moulded body Shoe part Ploss part Point

Point

rib

lateral rib lateral rib inner rib inner rib

1 sagging body

2 shoes

3 pala

4 points

5 points

6 costolature

7 lateral costolature

8 lateral costolature

9 internal framing 10 internal framing

Cuts A-R

sections

Claims (5)

Expectations 1 . Swimming fin with higher efficiency,
characterized in that a rib (6) is provided on the lower middle section of the fin part (3), which rib has a thickness such that it is greatest at the front end section of a shoe part (2) and approaches zero shortly before the end region of the fin part, the rib (6) allowing the stiffening of the fin part (3) at the connection point between the shoe part (2) and the fin part (3) and allowing unhindered bending of the end region of the fin part (3) as well as the execution of movements for expanding and contracting the V-shape of the fin part. 2. Swimming fin with higher efficiency according to claim 1,
characterized, that it consists of a shaped body (1) with one end, on which a shoe part (2) is provided which is open in the rear area and which is made of soft material and continues towards the opposite end with a fin part (3) which has a clearly pronounced V-shape in the end section of the fin part (3), which goes towards zero near the shoe part (2), the V-shape tending to widen under the effect of the swimmer's pedaling movement and to contract in the pulling phase. -2- 3. Swimming fin with higher efficiency according to the preceding claims, characterized, that two lateral ribs (7, 8) are provided on the upper side of the fin part (3), which follow the outer profile of the fin part (3) from the front end point of the shoe part (2) to the end of the fin part (3). 4. Swimming fin with higher efficiency according to the preceding claims, characterized, that two radial inner ribs (9, 10) are provided on the upper side of the fin part (3), which together with the lateral ribs (7, 8) help to keep the flow medium in the same direction,
and that the propulsive forces during swimming drive the flow towards the trailing edge, forming a jet of the flow medium which increases the effect of the fin and at the same time prevents the formation of vortices. 5. Swimming fin with higher efficiency according to claim 1,
characterized, that fastening points (4, 5) for straps on the shoe part (2) are formed at a location that is higher than the normal position, so that the strap running in the upper part of the heel ensures a better fit.