Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS3810269 A
Publication typeGrant
Publication dateMay 14, 1974
Filing dateSep 14, 1972
Priority dateSep 14, 1972
Publication numberUS 3810269 A, US 3810269A, US-A-3810269, US3810269 A, US3810269A
InventorsTabata K, Togasaka M
Original AssigneeTabata K, Togasaka M
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Swimmer{40 s foot fin
US 3810269 A
Abstract
A swimmer's foot fin is provided with a blade which slopes at an angle downwardly from a foot receiving portion. This blade includes sloping areas which form an inverse V-section to decrease the profile drag of the blade. Additionally, the lateral edges of the blade have ribs projecting above and below the blade and supplementary propulsive areas that are angled upwardly to form additional flow channels to direct the water during the kicking movement of the swimmer's foot to control turbulent flow and aid the propulsive effect of the kick.
Images(3)
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

nited States Patent [1 1 Tabata et a1.

1451 May 14,1974

1 1 SWIMMER'S FOOT FIN [76] Inventors: Kazuo Tabata, 1-3-17 Higashi-Komagata, Surnido-ku, Tokyo; Masanari Togasaka, 768 Kisone, Yashio-cho, Minami Saitama-gun Saitama. Japan [22] Filed: Sept. 14. 1972 [21] Appl. No.: 289,076

[52] U.S. Cl. 9/309 [51] Int. Cl A63b 31/10 [58] Field of Search 9/309, 301

[56] References Cited UNITED STATES PATENTS I 2,889,563 6/1959 Lamb et a1 9/309 3,411,165 11/1968 Murdoch 9/309 3,019,458 2/1962 Barbieri et al. 9/309 FOREIGN PATENTS OR APPLICATIONS 1,419,398 10/1965 France 9/309 Primary Examiner-Duane A. Reger Assistant Examiner-Gregory W. OConnor Attorney, Agent, or Firm-Flam & Flam [57] ABSTRACT A swimmers foot fin is provided with a blade which slopes at an angle downwardly from a foot receiving portion. This blade includes sloping areas which form an inverse V-section to decrease the profile drag of the blade. Additionally, the lateral edges of the blade have ribs projecting above and below the blade and supplementary propulsive areas that are angled upwardly to form additional flow channels to direct the water during the kicking movement of the swimmers foot to control turbulent flow and aid the propulsive effect of the kick.

1 Claim, 6 Drawing Figures PATENTEWY 14 1914 381 0.269

sum 2 ur a The present invention relates to swimmers foot fins, such as are used for example when skin-diving" or carrying out underwater operations.

It is an object of the present invention to provide a swimmers foot-fin wherein axial configuration of a blade portion is modified so as to allow its smooth entering into the water and to give direction to and increase the water current in the area of surface which acts against the water whereby a turbulent flow is controlled and hence increasing of a propulsive effect is obtained.

Another object of the present invention is to provide a swimmers foot-fin wherein a blade portion thereof is build up thinly in a degree that such construction does not weaken the strength of the blade portion but lighten the total weight of the foot fin so that the swimmers weariness with propulsive movements may be lessened.

Further objects of the present invention and advantages thereof may be best understood by reference to the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective elevation of one embodiment of the foot fin according to the present invention, seen from one side and above;

FIG. 2 is a perspective underplan of the foot fin of FIG. 1;

FIG. 3 is a section on the line X-X of FIG. 1;

FIG. 4 is a section on the line Y-Y of FIG. 1;

FIG. 5 is a schematic diagram to illustrate the manner in which the foot fin operates; and

FIG. 6 is a perspective elevation of another embodiment of the foot fin according to the present invention, seen from one side and above.

Similar reference characters refer to similar parts throughout the several views of the drawings.

Referring now to FIGS. 1 to 5, the foot fin, designated generally by reference numeral 1], is made as a one-piece moulding of a resiliently flexible material such as rubber or plastics and comprises a shoe portion 12 adapted to receive the swimmers foot and a blade portion 13 which forms a forward extension of the shoe portion and which has the effect of obtaining a propulsive effect by the swimmers alternative kicking movements up and down with the foot. The blade portion 13 extends forwardly of the substantially flat plantar region of the shoe portion in such a manner that each of both sides of the blade portion with an axial center line therebetween bends at a suitable angle downwardly thereby to obtain an inverse V-section and to form propulsive slope-areas 13a and 13b. Each ends of these propulsive slope-areas 13a, 13b in the axial direction generally parallel to the axial center line of the blade portion 13 is provided with ribs 14 and 15 which are projecting symmetrically above and below with an acute angle. At a portion immediately below the axial center line of the blade portion 13, there is also provided a rib l6 projecting downwardly with similar acute angle to that of the ribs 14 and 15. Each ends of these propulsive slope-areas 13a, 13b in the axial direction generally parallel to the axial center line of the blade portion 13 and in the extreme lateral portions over the ribs 14, 15, there are provided supplementary propulsive narrow slope-areas 13c, 13d each extending obliquely and upwardly with a suitable angle contrary to as in the case of the propulsive slope-areas 13a, 13b, As will be obvious from FIG. 3, the lateral sides of the blade portion 13 in its axial direction are formed with water-flow channels, each of the channels being defined by the propulsive slope-areas 13a, 13b and the upper ribs l4, 15; by the supplementary propulsive slope-areas 13c, 13d and the upper ribs I4, 15; or by the propulsive slope-areas 13a, 13b and the supplementary propulsive slope-areas 13c, 13d.

The provision of the propulsive slope-areas 13a. 13b will decrease the profile drag of the blade portion 13 and allow its smooth entering into the water, and the provision of the water-flow channels l7, 18 will cause the water-flow divided by the upper ribs 14, 15 during the kick movements of the swimmers foot to ejectively flow toward the direction parallel to the propulsive direction, whereby a turbulent flow of the water is controlled, a balanced swimming and propulsive effect is.

obtained.

Such modification in the axial configuration of the blade portion 13 and the arrangements of the ribs 14, 15 and 16 as shown and described above in connection with FIG. 3, will allow the blade portion to be build up thinly without weakening the strength thereof, so that the total weight of the foot fin 11 is lightened and the swimmers weariness with propulsive movements may be lessened.

The forward end of the blade portion 13 is provided witha slope-area 13c bending slightly downwardly with a suitable angle. Provision of such slope-area 13a is intended to merely obtain a beautiful profile of the footfin 11 and produces no particular advantageous effects on the propulsive movement. In this connection, it will be appreciated that if the slope-area 13a does maintain its designed configuration during the swimmers driving stroke by moving his lower limb 19 upwardly (FIG. 5) without coincidentally and resiliently following the water influence acting thereagainst, the speed of propulsive movement will naturally be decreased by the resistance produced by the water acting against such slope area 132. The slope area 13c according to the present invention, however, is build up toreably thinly in a degree that during the swimmers alternate kicking movements up and down as in FIG. 5 it may conform to the water resistance acting thereagainst and present a generally flat configuration, as will be obvious from FIG. 3. Accordingly, no such drawbacks, as referred to above will not be produced by the provision of the slope-area 13:: at the forward end of the blade portion 13.

Referring now to FIG. 6 showing another embodiment according to the present invention, the foot fin is designated generally by the reference numeral 111. This foot fin 111 is almost identical in its design to the foot fin 11 according to the embodiment previously referred to, and is intended to offer certain advantageous effect. Specifically, each of the forward ends of the upper/lower ribs l4, 15 is provided with vertical blade portions 114 and 115 respectively, these blade portions 114, 115 being made integral with the ribs l4, 15. These vertical blade portions 114, 115 is designed to present a configuration as well as a function like the vertical tail of an airplane shows and offers so that the directional stability of the blade portion 13 in the propulsive movement may advantageously be maintained. In this connection, it is to be noted that the lower vertical blade portions 114, 115 will not be so important as the upper vertical blade portions 114, 115 to obtain the above-mentioned effect. In other words, provision of the lower vertical blade portions 114, 115 will not be a prerequisite.

While the particular embodiments of the present invention has been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

What we claim is:

1. In a swimmers foot fin of one-piece molded plastic wardly at an angle to the plane of said plantar region from a place located near the forward end of said plantar region; said blade portion having two side parts angled laterally from a center line of the fin to define an inverted V-shaped dihedral angle; said side parts having lateral boundaries there being ribs at the lateral boundaries of said side parts and extending from the sides of said plantar region on the outside of said shoe portion to a point located at the frontal portion of said blade portion; there being a central rib extending longitudinally on the under side of said blade portion and operative in conjunction with said ribs to maintain a cup configuration on the underside of said fin upon downward effort being imposed thereon by the user; said blade portion having at the outer sides of said ribs, supplementary propulsive flanges each extending 'obliquely and upwardly to form on the inside and outside of each rib, a pair of companion water flow channels to achieve a controlled turbulent flow and a balanced swimming and propulsive effect.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2889563 *Feb 27, 1956Jun 9, 1959Lamb Edward WSwim flipper
US3019458 *Sep 29, 1958Feb 6, 1962De Barbieri EttoreSpoon-shaped swim-fin
US3411165 *Dec 12, 1966Nov 19, 1968Frank N. MurdochSwim fin
FR1419398A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4233925 *Feb 21, 1979Nov 18, 1980Proctor Douglas B IPaddles for boats
US4664639 *Aug 12, 1985May 12, 1987Schneider John DTube Fisherman's foot fin
US4737127 *Oct 7, 1986Apr 12, 1988Under Sea Industries, Inc.Hydrodynamic swim fin
US4775343 *Nov 12, 1985Oct 4, 1988Undersea Industries, Inc.Hydrodynamic swim fin
US4778423 *Oct 19, 1987Oct 18, 1988Ciccotelli Stephen SThermoplastic swim fin
US4838824 *Nov 6, 1987Jun 13, 1989Mccredie Donald BSwimming flipper
US4887985 *Feb 3, 1988Dec 19, 1989Amf IncorporatedSwim fin provided with a self-shaping, fluid flow conveying and controlling canal-like member
US5183424 *Mar 13, 1992Feb 2, 1993Field John DSwimming flipper
US5421758 *Aug 18, 1993Jun 6, 1995Watson; Michael P.Scuba fin
US5597336 *Feb 27, 1995Jan 28, 1997Evans; Robert B.Unique swim fin
US5899781 *Nov 7, 1997May 4, 1999Mclaughlin; Matthew M.Swim fin incorporating pronation compensation structure
US6053788 *Aug 13, 1998Apr 25, 2000Htm Sport S.P.A.Swimming flipper
US6086440 *Jan 11, 1999Jul 11, 2000Fechtner; RyszardSwim fin and monofin with flapping foil
US6568973Feb 21, 2001May 27, 2003Salvas Sub S.P.A.Swim or dive fin
US6568974Sep 26, 2001May 27, 2003Scubapro Europe S.R.L.Swim and scuba fin
US6585548Jan 4, 2002Jul 1, 2003Mccarthy Peter T.High efficiency hydrofoil and swim fin designs
US6607411Jan 4, 2002Aug 19, 2003Mccarthy Peter T.High efficiency hydrofoil and swim fin designs
US6884134Jul 18, 2003Apr 26, 2005Mccarthy Peter T.High deflection hydrofoils and swim fins
US6918805Jan 22, 2004Jul 19, 2005Mccarthy Peter T.Methods for creating consistent large scale blade deflections
US6979241Aug 6, 2002Dec 27, 2005ZoomersSwim training fin
US7018256Jun 25, 2004Mar 28, 2006Mccarthy Peter TMethods for creating large scale focused blade deflections
US7101240Nov 13, 2003Sep 5, 2006Mccarthy Peter THigh efficiency hydrofoil and swim fin designs
US7465205Jul 19, 2006Dec 16, 2008Mccarthy Peter TMethods for creating consistent large scale blade deflections
US7581997Sep 5, 2007Sep 1, 2009Mccarthy Peter TMethod for creating consistent large scale blade deflections
US7601041Aug 21, 2006Oct 13, 2009Mccarthy Peter THigh deflection hydrofoils and swim fins
US7862395Sep 7, 2007Jan 4, 2011Mccarthy Peter TMethods for creating consistent large scale blade deflections
EP0880379A1 *Jan 9, 1997Dec 2, 1998McCARTHY, Peter ThomasHigh efficiency hydrofoil and swim fin designs
EP0908198A1 *Aug 6, 1998Apr 14, 1999HTM SPORT S.p.A.Swimming flipper
EP1389484A2 *Jul 22, 2003Feb 18, 2004Martin Philip Dr. HullImproved swim training fin
WO1994015676A1 *Jan 18, 1993Jul 21, 1994Robert B EvansUnique swim fin
WO1999024123A1 *Sep 15, 1998May 20, 1999Mclaughlin Matthew MSwim fin incorporating pronation compensation structure
Classifications
U.S. Classification441/64
International ClassificationA63B31/00, A63B31/11
Cooperative ClassificationA63B31/11
European ClassificationA63B31/11