Swimming flipper with controlled-flexibility blade

Abstract: Swimming flipper including a shoe portion (1) and a blade portion (2), two ribbings (102) being provided along the outer lateral rims of said flipper, said ribbings (2) being symmetrical to the plane of said blade portion (2) and extending along a substantial portion of said shoe (1) with a decreasing height towards the free end of said blade portion (2); two carvings (112, 122) are provided on each of said ribbings (102) near the shoe portion (1) of said flipper, substantially V-shaped, above and below the plane of the blade portion (2), placed at a suitable distance one from the other, arranged so as to create two bending lines of the plane of said blade (2), and contrast means (202, 302; 402) for the bending movement of said blade (2) being provided on the upper surface of said blade portion (2).

Description: The present invention relates to a swimming flipper, and in particular to a flipper in which at least one blade portion shows a certain degree of controlled flexibility with respect to the shoe of the flipper itself. In flipper swimming the thrust obtained by means of the flipper is not due to the whole movement made by the swimmer's foot, but only to the stage in which his/her leg is bending. The other stage, known as passive stage, therefore causes an extra labour for the diver, with no advantages from the point of view of movement. This negative aspect is even more evident with commonly used flippers, in which the blade portion is made of a relatively stiffer material; such configuration, though being advantageous on the one hand because it improves the thrusting power of the flipper, increases, on the other hand, the useless expenditure of energy in the so-called passive stage. Therefore, it has been thought to reduce the diver's effort considerably during this stage, by conveying a certain degree of controlled flexibility to the flippers, that is to say, by making them flexible only during the passive stage. In the co-pending European Patent EP-A-998 962 of the same Applicant, a swimming flipper is described whose blade is hinged onto the shoe so as to show a controlled degree of flexibility. Another solution concerning this includes two carvings, substantially V-shaped, on each of the lateral ribbings stiffening the blade, said carvings being placed above and below the plane of the blade itself, one opposite the other and arranged so as to create on the blade plane a bending line, which is located near the shoe of the flipper itself, perpendicularly to the longitudinal axis of the flipper. However, the bending control only depends on the power of reciprocal contrast between the sloping surfaces of the carvings, said power being rather limited and therefore effective to a limited degree for this purpose. Moreover, the blade area where the bending takes place is extremely weakened. US-A-3 082 442 also discloses a swimming flipper corresponding to the preamble of claim 1. The present invention aims at providing a swimming flipper having said controlled flexibility for the blade, without hinging the latter to the shoe, that is to say, without carrying out the sole portion of the shoe and the blade separately and connecting them afterwards. The object of the present invention is therefore a swimming flipper including a shoe portion and a blade portion, two ribbings being provided along the outer lateral rims of said flipper, said ribbings being symmetrical to the plane of said blade portion and with decreasing height towards the free end of said blade portion, characterised in that two carvings, substantially V-shaped, are provided on each of said ribbings near the shoe portion of said flipper, above and below the plane of the blade portion, said ribbings being placed at a suitable distance and staggered one with respect to the other, so as to create two bending lines for the plane of said blade, and contrast means for the bending being provided on the upper surface of said blade portion of the flipper. Said carvings are advantageously carried out on each ribbing, placed at a distance one from the other so that the point of maximum depth of one carving corresponds to one of the points of minimum depth of the other carving. In particular, the configuration in which the carving above the blade plane is turned towards the free end of the blade seems to be more effective. In a form of embodiment the outer rims of the ribbings are coated with beads made of elastomeric material, so as to ensure the elastic response to the bending movements and therefore to reduce the load placed onto the blade portion participating in said movements. Further advantages and features will be evident from the following description of some forms of embodiment of the swimming flipper according to the present invention, carried out as a mere non limiting example, referring to the enclosed drawings, where: fig. 1 is a perspective view of a first form of embodiment of the flipper according to the present invention; fig 2 is an enlarged detail in lateral elevation of the flipper in fig. 1; and fig. 3 is an execution variant of the flipper according to the present invention. Figure 1 shows a swimming flipper according to the present invention; the numeral 1 indicates the shoe portion of said flipper, provided with the heel belt 101 connected to the buckles 201. The flipper includes the blade portion 2, along whose lateral rims there are the ribbings 102 going up along a substantial portion of the shoe 1. Such ribbings are symmetrical to the plane of the blade 2, and their height decreases towards the free ends of said blade. On both ribbings 102 the carvings 112 and 122 are provided above and below the plane of the blade 2 and near the portion of the shoe 1, said carvings being substantially V-shaped and with a blunted vertex. Beads 132 made of elastomeric material are provided on both rims, the lower and the upper one of each ribbing. The blocks 202, 302 are located, obtained as one piece or applied onto the upper surface of the blade 2, in the area corresponding to the one which contains the carvings 112, 122 and near the ribbings 102. The blocks 202, 302 show flat surfaces 212, 312, one opposite the other and inclined with a given angle with respect to the plane of the blade 2. From figure 2 it is possible to verify that in each of the ribbings 102, the carving 112 above the plane of the blade 2 and the carving 122 below such plane are not placed opposite each other. As a matter of fact, the axes of the two carvings are located at such a distance d that the point of maximum depth of the carving 112 corresponds to a point of minimum depth of the carving 122, the carving 112 being turned towards the free end of the blade 2. Figure 3 shows an execution variant of the swimming flipper according to the invention; the same parts are indicated with the same numerals. A single block 402, obtained integrally with or applied to said blade 2, is centrally placed on the upper surface of said blade 2. Such block is opposite a levelling surface 301, obtained on the front end of the shoe 1. Both the levelling surface 301 and the flat surface 412 of the block 402 are inclined so as to contrast the bending of the blade 2. The working of the flipper according to the present invention will be evident from what follows. The carvings 112, 122 located on the ribbings 102 allow the blade to bend in the area between the lines connecting the axes of said carvings. Such area, though limited in its breadth, is nevertheless broader than a mere line, thus ensuring a better resistance to the bending load. Moreover, said resistance is increased by the beads 132 made of elastomeric material, working as elements of elastic response. The distance d between the axes of the carvings is established considering a minimum value, below which the two carvings would practically be one opposite the other and the structure of the blade 2 would be weakened, and a maximum value, above which there would be no interaction between the two carvings in the bending movement of said blade. Moreover, also the inclination of the lateral walls of said carvings 112, 122 must be such as to promote the bending movement without endangering the structural integrity of the blade. In practice, there is an angle 20° to 45° between the plane of the blade 2 and the lateral wall of the carving. The contrast means for the bending movement during the active stage of flipper swimming, that is to say, the blocks 302 and 202 in the form of embodiment of figure 1 and the block 402 and the levelling surface 301 on the front end of the shoe 1 are shaped so as to limit the bending angle of the blade. The flat surfaces bound to come into contact reciprocally are inclined with respect to the plane of the blade so as to limit as much as possible the bending range during the passive stage of flipper swimming; the angle between said surfaces and the plane of the blade 2 is preferably of 60-80°.

Claims: Swimming flipper including a shoe portion (1) and a blade portion (2), two ribbings (102) being provided along the outer lateral rims of said flipper, said ribbings (102) being symmetrical to the plane of said blade portion (2) and extending along a substantial portion of said shoe (1) with a decreasing height towards the free end of said blade portion (2), with two carvings (112, 122) on each of said ribbings (102) near the shoe portion (1) of said flipper, said carvings (112, 122) being substantially V-shaped, above and below the plane of the blade portion (2), the carvings are placed at a suitable distance and staggered one with respect to the other, so as to create two bending lines of the plane of said blade (2), and contrast means (202, 302; 402) for the bending of said blade (2) being provided on the upper surface of said blade portion (2). Swimming flipper according to claim 1, in which said carvings (112, 122) are carried out on each ribbing (102) at such a distance that the point of maximum depth of one carving (112) corresponds to one of the points of minimum depth of the other carving (122). Swimming flipper according to claim 2, in which the carving (112) on the plane of the blade (2) is turned towards the free end of said blade (2). Swimming flipper according to one of the previous claims 1 to 3, in which said carvings (112, 122) have rounded vertices. Swimming flipper according to any of the claims 1 to 4, in which the lateral walls of said carvings (112, 122) are inclined towards the plane of the blade portion (2) with an angle between 20° and 45°. Swimming flipper according to any of the previous claims 1 to 5, in which the outer rims of the ribbings (102) are coated on their whole length with beads (132) made of elastomeric material. Swimming flipper according to any of the previous claims 1 to 6, in which said contrast means for the bending movement of said blade (2) include at least a pair of contrast elements (202, 302; 402, 301), protruding out of the plane of said blade (2), placed near the bending lines of said plane and with their surfaces (212, 312; 412, 301) opposite one to the other, flat and inclined of a given angle with respect to the plane of said blade (2). Swimming flipper according to claim 7, in which said contrast means include two pairs of contrast elements (202, 302), each of them being located near one of the ribbings (102) of said blade. Swimming flipper according to claim 7, in which one of said contrast elements (301) is obtained directly on the front end of the shoe portion (1), the other one (402) being placed opposite to the first. Swimming flipper according to any of the claims 7 to 9, in which said opposite flat surfaces (212, 312; 412, 301) of said contrast elements (202, 302; 402, 301) are inclined with respect to the plane of the blade (2) with an angle of about 60-80°.

Inventors: GAROFALO GIOVANNI, VIALE MARIO, GAROFALO, GIOVANNI, VIALE, MARIO
Applicants: HTM SPORT SPA, HTM SPORT S.P.A.
Application year: 2000
Main classification: A63B31
IPC codes: A63B31