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

Claim 11:
12. 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 at least one elongated harder portion made with said significantly harder thermoplastic material that is disposed in said blade member adjacent to said blade member longitudinal center axis and extends along a significant portion of said blade member length, said elongated harder portion having harder portion outer side edges and a harder portion transverse plane of reference that extends between said harder portion outer side edges;
(c) providing said blade member with two elongated flexible membrane members made with said flexible thermoplastic material that are each disposed in said blade member in an area between said harder portion outer side edges and said blade member outer side edges, each of said membranes having a membrane outer side edge region adjacent said blade member outer side edges and a membrane inner side edge region adjacent to said harder portion outer side edges, each of said membranes having a membrane transverse dimension between said membrane outer side edge region and said membrane inner side edge region, said blade member having a membrane region outer edge transverse plane of reference that extends across the width of said blade member between each said membrane outer side edge region of said two elongated flexible membrane members, each of said membranes having a membrane transverse cross section shape that extends between said membrane outer side edge region and said membrane inner side edge region;
(d) providing a biasing force that urges said membrane transverse cross sectional shape to have at least one transversely inclined membrane resting state alignment that is oriented at transversely inclined angle relative to said membrane outer edge region transverse plane of reference when said swim fin is in a motionless state of rest, said biasing force urging said at least one transversely inclined membrane resting state alignment to have an orthogonally directed 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;
(e) arranging said two elongated flexible membrane members to experience transverse pivoting around a substantially lengthwise axis adjacent to each said membrane outer side edge region wherein said transverse pivoting causes each said membrane inner side edge and said harder portion 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 harder portion to move relative to said rib member midpoint transverse plane of reference to a first orthogonally deflected harder portion position occurring during a first kicking stroke direction within said repetitive reciprocating kicking stroke cycles and a second orthogonally deflected harder portion 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
(f) arranging said reciprocating orthogonal movement to occur over a harder portion orthogonal reciprocating deflection distance that extends between said first orthogonally deflected harder portion position and said second orthogonally deflected harder portion position during said repetitive reciprocating kicking stroke cycles, said transversely inclined membrane resting state alignment within each of said membranes being sufficiently transverse to said orthogonal direction of said reciprocating orthogonal movement to create significantly reduced membrane bending resistance to said reciprocating orthogonal movement so as to permit said harder portion orthogonal reciprocating deflection distance to extend to at least 3% of said blade member transverse dimension along a majority said blade member length.