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

Claim 18:
19. 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;
(b) providing said swim fin with a pivoting blade region that is arranged to pivot to a lengthwise reduced angle of attack of at least 10 degrees around a transverse axis that is between the heel portion of said foot attachment member and said longitudinal midpoint during at least one kicking stroke direction that uses a cruising speed kicking stroke force used to achieve a cruising speed while swimming;
(c) arranging at least one of said opposing surfaces of said blade member within said pivoting blade portion to form an orthogonally spaced resting state transversely concave surface region that is orthogonally spaced away from said rib member midpoint transverse plane of reference to an orthogonally spaced resting state position when said swim fin is in a motionless state of rest so as to create an orthogonally spaced resting state scoop region having an orthogonally spaced resting state scoop volume that exists between said orthogonally spaced resting state transversely concave surface region and said transverse plane of reference when said swim fin is in said motionless state of rest wherein said orthogonally spaced resting state scoop volume has an orthogonally spaced resting state transverse cross sectional shape having an orthogonally spaced resting state scoop transverse dimension that is at least 40% of said blade member transverse dimension along a significant portion of said blade member length, said orthogonally spaced resting state scoop volume having an orthogonally spaced resting state vertical dimension between at least one orthogonally spaced portion of said orthogonally spaced resting state transversely concave surface region and said rib member midpoint transverse plane of reference that is at least 3% of said blade member transverse dimension along a majority of the surface area said second half portion, and said orthogonally spaced resting state scoop volume having an orthogonally spaced scoop longitudinal dimension that is at least 20% of said blade member length;
(d) providing said swim fin with a biasing force arranged to urge said at least one orthogonally biased portion of said orthogonally spaced concave surface region in a first orthogonal direction away from said rib member midpoint transverse plane of reference and toward said at least one orthogonally spaced position at said orthogonally spaced resting state vertical dimension of at least 3% of said blade member transverse dimension along a majority of said blade member length while said swim fin is in said motionless state of rest;
(e) arranging said biasing force to permit said orthogonally spaced resting state vertical dimension to be substantially maintained along a significant portion of said concave scoop shaped contour under the exertion of water pressure created when said orthogonally spaced resting state transversely concave surface region is the attacking surface through the surrounding water while using a maneuvering kicking force that is used to maneuver aggressively while swimming;
(f) 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, a significant portion of said at least one elongated harder portion is arranged to experience reciprocating orthogonal movement relative to said rib member midpoint transverse plane of reference during a reciprocating kicking stroke cycle that uses said cruising speed kicking force;
(g) providing said blade member with two elongated flexible folded membrane members made with said flexible thermoplastic material, each of said two elongated flexible folded membrane members being disposed in said blade member on in an area between said harder portion outer side edges and said blade member outer side edges, each of said two 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 two folded membranes having a folded membrane apex portion in between said first membrane portion outer side edge and said second membrane outer side edge;
(h) arranging each of said two elongated folded membrane members to experience expansion from a substantially folded condition existing when said swim fin is in said motionless state of rest to a significantly expanded condition under said exertion of water pressure created during at least one phase of said reciprocating kicking stroke cycle while using said cruising speed kicking stroke force, said expanded condition of said expandable folded membrane being arranged to cause a majority of the surface area of said three quarter portion of said blade member to experience a blade portion orthogonal movement relative to said rib member midpoint transverse plane of reference from a resting state blade portion position existing when said swim fin is in said motionless state of rest to an orthogonally spaced expanded state position under said exertion of water pressure that is orthogonally spaced from said resting state blade portion position by an orthogonally spaced expanded state vertical dimension that is at least 5% of said blade member transverse dimension along a majority of said second half portion of said blade member under said exertion of water pressure created during said at least one phase of said reciprocating kicking stroke cycle that uses said cruising speed kicking stroke force.