Swimming flipper

Abstract: Swimming flipper of the type in which the flipper part (1) has at least two or more channels (3,3',4,4') for restricting and directing the streams of fluid generated during swimming, characterized in that said channels (3,3',4,4') are made with opposite concavities.

Description: The present invention relates to swimming flippers and especially to flippers of the type in which the flipper part has two or more channels for restricting and directing the streams of fluid generated during swimming. More specifically, but not exclusively, the invention relates to flippers of the type described above, in which said channels are made in a more pliable material than that of the rest of the flipper part. FR-A-2355529 disclose a swim fin in which the flipper part comprises a central channel and two through openings disposed at both sides of said central channel, and cooperating with two flap valve-like elements. In document EP-A-0308998 is disclosed a method for the production of a swim fin having the shoe portion made of relatively supple material and the blade portion of a comparatively stiff material, said blade portion being provided with at least one longitudinally extending deformable membrane-like element, this element being obtained by molding the same supple moldable material of the shoe portion into slits formed on the said blade portion. The main drawback of the known flippers of the type mentioned above is that said channels cause an excessive deformation or "elastic yielding" of the flipper part when the flipper stroke is in a direction which coincides with the concavity of said channels, whereas when the flipper stroke is in the opposite direction, the flipper part tends to become excessively rigid. These and other objects which will be detailed below are achieved by the swimming flipper according to the invention which comprises: a shoe portion; a flipper part extending forwardly from said shoe portion to a fore edge, said flipper part being of a first material which is relatively stiff and having longitudinal slits therein, a flow channel being formed in each of said longitudinal slits and extending rearwardly from said fore edge of the flipper part, said flow channels being of a second material which is less stiff than said first material; characterized in that said flipper part comprises at least two side flow channels and one central flow channel, the side channels extending concavely away from the flipper part in one direction and the central channel extending concavely away from the flipper part in the opposite direction. Advantageously, according to the preferred embodiment of the invention, the flippers have four adiacent channels on each flipper part, the two centermost channels being made with opposite concavities relative to those of the two side channels. According to an additional feature of the invention, in the case of a flipper with three or more channels, the central channels are preferably made narrower than the side channels in order to limit even further the "elastic yielding" of the flipper part. Further features and advantages of the flipper according to the invention will emerge more clearly on reading the following description of certain preferred embodiments of said flipper, said description being made with reference to the appended drawings in which: Figure 1 is a perspective view of a swimming flipper having four flow channels according to the invention, in which the shoe part of the flipper has been partially cut away. Figure 2 is a cross-section along the line II-II of Figure 1, and Figure 3 is a cross-section, similar to that of Figure 2, of an embodiment of a flipper having three flow channels. With reference to the drawings, and with particular reference to Figures 1 and 2 thereof, the flipper illustrated is of the type comprising a flipper part 1, obtained by moulding a relatively rigid material, joined by means of a further moulding operation to a shoe part 2 which is made of a softer material, of the consistency of rubber. The flipper part 1 has slits 101, 101', 102, 102' formed in it which extend from the leading edge 201 of the flipper part 1 towards the middle in the direction of the base part 202 of said flipper part 1. The flow channels 3, 3', 4, 4' are formed inside these slits 101, 101', 201, 201' by moulding using the same material as that used to mould the shoe part 2. Advantageously, the material used to form the flow channels 3, 3' is directed into the rear ends of the side slits 101, 101' at the time of moulding of the shoe 2, via injection ducts 301 formed in the flipper part 1, and comes out of the front of these side slits 101, 101' after having formed the flow channels 3, 3' by running along a front duct formed between the front end of the mould and the leading edge of the flipper, where it forms the front edge 401, then travelling as far as the two central slits 102, 102', at which point it forms the flow channels 4, 4'. In accordance with the invention, the flow channels 4, 4' have an opposite concavity to that of the flow channels 3, 3', as clearly illustrated in Figures 1 and 2. The flipper is completed in the usual way by the two side ribs 5, 5' and has a series of small fins 6, 6', 7 which, in addition to stabilizing the flipper during swimming, are also used to help position the flipper part 1 correctly in the mould in which the shoe part is injected, so as to prevent the sides of the flipper part moving during moulding of the channels 3, 3'; 4, 4'. The advantages resulting from the flipper described will be self-evident. The channels 3, 3', 4, 4' with opposite concavities allow: a) improved channelling of the flow of fluid in both directions of flipper stroke, and b) excellent bending of the flipper in both stroke directions. As illustrated, the central channels 4, 4' are narrower than the side channels so as to further limit the "elastic yielding" of the flipper part 1 during swimming. Figure 3 shows a variant, three-channelled embodiment of the flipper shown in Figures 1 and 2. According to this variant, the flipper part 1 has a single channel 4'' at its centre, this channel having an opposite concavity to that of the side channels 3, 3', for the same purposes as those described with reference to the four-channelled flipper.

Claims: Swimming flipper comprising: a shoe portion (2); a flipper part (1) extending forwardly from said shoe portion (2) to a fore edge (401), said flipper part being of a first material which is relatively stiff and having longitudinal slits therein (101, 101', 102, 102'), a flow channel (3, 3', 4, 4') being formed in each of said longitudinal slits (101, 101', 102, 102'), extending rearwardly from said fore edge (401) of the flipper part (1), said flow channels (3, 3', 4, 4') being of a second material which is less stiff than said first material; characterized in that said flipper part (1) comprises at least two side flow channels (3, 3') and at least one central flow channel (4, 4'), the side channels (3, 3') extending concavely away from the flipper part (1) in one direction and the central channel (4, 4') extending concavely away from the flipper part (1) in the opposite direction. Flipper according to Claim 1, characterized in that it has four channels, said channels comprising a first pair of side channels (3, 3') and a second pair of central channels (4, 4'). Flipper according to claim 2, characterized in that said central channels (4, 4') are narrower than the side channels (3, 3'). Flipper according to Claim 1 to 4, characterized in that it has a series of small projections or fins (6, 6', 7) located on the areas of the flipper part (1) which separate the individual flow channels. Method of manufacturing a flipper comprising at least two side channels and at least one central channel according to the Claims 1 to 4 above, of the type consisting of a flipper part made of relatively rigid material on which a shoe part, made of softer material is moulded, said method comprising: forming a series of slits in the flipper part which consist of two side slits and at least one central slit which extend from the leading edge of the flipper part in the direction of the base part thereof; forming a series of injection channels in said flipper part which extend from the base area of the flipper as far as the rear ends of the two side slits of the flipper part; injecting a material forming said flow cannels into said slits, via said injection channels; characterized in that the injected material is directed along the leading edge of the flipper up to said central slits, with said material running into said central slits, thereby forming said central flow channels. Method according to Claim 5, in which said flipper part has, at least n the areas separating said slits, a series of projections which can be inserted into corresponding recesses in the mould so as to prevent the end parts of the flipper from moving during moulding of the channels. Method according to Claim 6, in which said projections are in the form of small fins.

Inventors: GAROFALO GIOVANNI, GAROFALO, GIOVANNI
Applicants: HTM SPORT SPA, HTM SPORT S.P.A.
Application year: 1993
Main classification: A63B31
IPC codes: A63B31