Patent ID: 11944873
Assignee: NATURE'S WING FIN DESIGN, LLC
Field: Furniture, games (Other fields)
Classification: CPC A | IPC A

Claim 5:
6. A method for providing a swim fin, said method comprising:
(a) providing a foot attachment member and a blade member in front of said foot attachment member, said blade member having a longitudinal alignment relative to said foot attachment member, said blade member having opposing surfaces, blade member outer side edges and a blade member transverse dimension between said blade member outer side edges, two sideways spaced apart elongated rib members that are connected to said blade member adjacent to said blade member outer side edges, said elongated rib members each having a rib upper edge portion and a rib lower edge portion with a vertical rib dimension between said rib upper edge portion and said rib lower edge portion and a rib vertical midpoint that is midway between said rib upper edge portion and said rib lower edge portion, a rib member midpoint transverse plane of reference that extends in a transverse direction between said rib vertical midpoints of said two sideways spaced apart elongated rib members, a root portion adjacent to said foot attachment member and a free end portion spaced from said root portion and said foot attachment member, a blade member length between said root portion and said free end portion, a longitudinal midpoint between said root portion and said free end portion, a three quarter position between said root portion and said midpoint, a one quarter position between said longitudinal midpoint and said free end portion, a first half portion between said root portion and said longitudinal midpoint, a second half portion between said longitudinal midpoint and said free end portion, a three quarter portion between said three quarter position and said free end portion, and a one quarter portion that is between said one quarter position and said free end portion, said blade member having a blade member longitudinal center axis midway between said outer side edges, at least one portion of said blade member being made with a significantly flexible thermoplastic material, at least one portion of said blade member being made with a significantly harder thermoplastic material that is substantially harder than said significantly flexible thermoplastic material, said significantly flexible thermoplastic material being connected to said significantly harder thermoplastic material with a thermal-chemical bond created during at least one phase of an injection molding process;
(b) providing said blade member with two elongated flexible folded membrane members made with said flexible thermoplastic material that are each disposed in said blade member on in an area between said blade member outer side edges, each of said folded membranes having a first membrane portion outer side edge, a second membrane outer side edge that is transversely spaced from said first membrane portion outer side edge, each of said folded membranes having a folded membrane apex portion in between said first membrane portion outer side edge and said second membrane outer side edge, said blade member having a folded membrane apex transverse plane of reference that extends transversely across said blade member between said folded membrane apex portions on each of said folded membranes, each of said folded membranes having a first membrane portion between said first membrane portion outer side edge and said folded membrane apex portion, each of said folded membranes having a second membrane portion between said folded membrane apex portion and said second membrane portion outer side edge, said first membrane portion having a first membrane portion transverse cross sectional alignment that extends between said first membrane portion outer side edge and said folded membrane apex portion, said second membrane portion having a second membrane portion transverse cross sectional alignment that extends between said folded membrane apex portion and said second membrane portion outer side edge, said first membrane portion transverse cross sectional alignment is arranged to be substantially more vertically oriented than transversely oriented when said swim fin is in a motionless state of rest, said second membrane portion transverse cross sectional alignment is arranged to be sufficiently more transversely oriented than said first membrane portion transverse cross sectional alignment when said swim fin is in said motionless state of rest;
(c) providing each of said folded membranes with a biasing force that urges a significant portion of said first membrane portion away from said folded membrane apex transverse plane of reference and to said first membrane portion transverse cross sectional alignment and urges said second membrane portion to said second membrane portion transverse cross sectional alignment when said swim fin is in said motionless state of rest, said biasing force urging at least two transversely spaced apart portions of each said folded membrane to be orthogonally spaced apart from each other by an orthogonal vertical dimension that is at least 3% of said blade member transverse dimension along a majority of said blade member length when said swim fin is in said motionless state of rest;
(d) arranging each of said folded membranes to experience reciprocating orthogonal movement in an orthogonal direction relative to said rib member midpoint transverse plane of reference in response to the exertion of water pressure occurring in said orthogonal direction during reciprocating kicking stroke directions that occur within repetitive reciprocating kicking stroke cycles when using a cruising speed kicking stroke force that is used to achieve a cruising speed while swimming, said reciprocating orthogonal movement causing said folded membranes to move relative to said rib member midpoint transverse plane of reference to a first orthogonally deflected position occurring during a first kicking stroke direction within said repetitive reciprocating kicking stroke cycles and to a second orthogonally deflected position occurring during a second kicking stroke direction that is oppositely directed to said first kicking stroke direction within said repetitive reciprocating kicking stroke cycles; and
(e) said reciprocating orthogonal movement is arranged to occur over an orthogonal reciprocating deflection distance between said first orthogonally deflected harder portion position and said second orthogonally deflected harder portion position during said repetitive reciprocating kicking stroke cycles that is at least 5% of said blade member transverse dimension over a majority of said blade member length during said repetitive reciprocating kicking stroke cycles when using said cruising speed kicking stroke force.