Patent ID: 6712656
Filing Date: 2004-03-30
Classification: A63B

Abstract:
A method for improving the performance of a swim fin, comprising:(a) providing a foot attachment portion; (b) providing at least one substantially flexible elongated load bearing rib member connected to said foot attachment portion and extending in front of said foot attachment portion, said rib member having a rib root portion near said foot attachment portion and said rib member having a rib free end portion remote from said rib root portion and said foot attachment portion, said rib member having a predetermined length between said rib root portion and said rib free end portion, said rib having a longitudinal midpoint between said rib root portion and said rib free end portion, said rib member having a first half portion located between said rib root portion and said midpoint, said rib having a second half portion located substantially between said midpoint and said rib free end portion; (c) providing at least one blade portion connected to said rib member; (d) providing said rib member with an extensible load bearing material, said extensible load bearing material being arranged to provide a major portion of the structural support of said at least one blade portion relative to said foot attachment portion as relatively light load conditions are exerted on said at least one blade portion during a light kicking stroke such as used by a swimmer to in an effort to reach a relatively slow to moderate swimming speed; (e) providing said rib member with a predetermined degree of flexibility, said predetermined flexibility is arranged to permit a predetermined light kick deflection angle of at least 10 degrees under said light load conditions, said rib taking on a corresponding light kick bend around a light kick bending radius; and (f) providing said rib member with a sufficiently tall vertical rib dimension relative to said light kick bending radius to permit a tension surface portion of said extensible load bearing material to experience a predetermined light kick elongation of at least 5 percent during said light kick deflection, said rib having a predetermined cross sectional shape along said length of said rib that is arranged to substantially reduce the occurrence of excessive buckling along said rib during said light kick deflection, said cross sectional shape of said rib is arranged to permit a significant amount of said light kick bend to occur within said first half portion of said rib member, said extensible material is sufficiently extensible to permit said tension surface portion to experience said light kick elongation range during said light kick deflection, said extensible material having sufficient elastic memory to permit the energy stored within said light kick elongation range to be released in the form of a substantially strong snapping motion at the end of said stroke.