초록 ▼

Designs and methods are disclosed for permitting permit scooped shaped swim fin blades (184) to flex around a transverse axis to a significantly reduced angle of attack while reducing or preventing the scooped blade portion (254) from collapsing or buckling under the longitudinal compression forces

Designs and methods are disclosed for permitting permit scooped shaped swim fin blades (184) to flex around a transverse axis to a significantly reduced angle of attack while reducing or preventing the scooped blade portion (254) from collapsing or buckling under the longitudinal compression forces (222) exerted on the scooped portion during a large scale blade deflection (212) by strategically alleviating or controlling such compression forces (222). Method are also disclosed for increasing flow capacity, effective scoop length, scoop depth over a greater length of the blade, reducing blade resistance to large scale deflections, reducing bending resistance within scooped blade portions (254) that are experiencing high levels of blade deflection. Methods are also provided for reducing lost motion and increasing propulsion during the inversion phase of a reciprocating kicking stroke cycle while also increasing the formation of a scooped blade region (254) during the inversion phase of the stroke cycle.

대표청구항 ▼

1. A method for providing a propulsion hydrofoil, comprising:(a) providing said hydrofoil with a blade member connected to a predetermined body, said blade member having an attacking surface, a lee surface, outer side edges, a root portion near said predetermined body and a free end portion spaced f

1. A method for providing a propulsion hydrofoil, comprising:(a) providing said hydrofoil with a blade member connected to a predetermined body, said blade member having an attacking surface, a lee surface, outer side edges, a root portion near said predetermined body and a free end portion spaced from said predetermined body, said blade member having a predetermined length between said root portion and said free end portion, said blade member having a longitudinal midpoint between said root portion and said free end portion, said blade member having a first half blade portion between said root portion and said longitudinal midpoint and a second half portion between said longitudinal midpoint and said free end portion, said blade member having sufficient flexibility to bow between said outer side edges to form a longitudinal channel shaped contour, said longitudinal channel shaped contour extends from said free end portion toward said root portion to base of said longitudinal channel shaped contour, said base being located a predetermined distance from said predetermined body, said longitudinal channel shaped contour having a predetermined longitudinal dimension between said free end portion and said base; (b) providing said first half blade portion of said blade member with sufficient flexibility to experience a predetermined lengthwise deflection from a predetermined neutral orientation to a predetermined reduced lengthwise angle of attack around a transverse axis during use, said transverse axis being located within said first half portion of said blade member; (c) providing said blade member with sufficient spring-like tension during said predetermined lengthwise deflection so as to permit said blade member to experience a significantly strong snapping motion from said predetermined lengthwise deflection toward said predetermined neutral position; (d) controlling the build up of longitudinally directed compression forces within said blade member sufficiently to permit said predetermined longitudinal dimension of said channel shaped contour to extend over a majority of said predetermined length of said blade member as said channel shaped contour experiences said predetermined lengthwise deflection to said predetermined reduced lengthwise angle of attack during use; and (e) arranging said blade member to have sufficient flexibility alone said predetermined longitudinal dimension to permit said blade member to form an S-shaped sinusoidal wave during the inversion portion of a reciprocating propulsion stroke, said blade member is arranged to control said longitudinally directed compression forces sufficiently to permit said blade member to form said channel shaped contour as said S-shaped sinusoidal wave is created. 2. The method of claim 1 wherein said blade member includes a stopping device arranged to prevent said predetermined lengthwise reduced angle of attack from reaching an excessively reduced angle that is not efficient at generating propulsion.3. The method of claim 1 wherein said snapping motion is sufficient to reduce the occurrence of lost motion during the inversion portion of a reciprocating stroke cycle.4. The method of claim 1 wherein spring-like tension is created as a portion of said blade member is forced to experience elastic elongation of at least 2% during said predetermined deflection.5. The method of claim 1 wherein spring-like tension is created as a portion of said blade member is forced to experience elastic elongation of at least 10% during said predetermined deflection.6. The method of claim 1 wherein a region of reduced material is disposed within said blade member near said base of said longitudinal channel shaped contour, said region of reduced material being arranged to permit said blade member to move sufficiently toward said predetermined body during said predetermined lengthwise deflection to significantly reduce the tendency for said blade member to experience lengthwise buckling between said base and said free end portion of said blade member.7. The method of claim 6 wherein said region of reduced material is a flexible region of reduced thickness within said blade member arranged to buckle around a relatively small radius near said base so as to relieve said longitudinally directed compression forces created within said channel shaped contour during said lengthwise deflection.8. The method of claim 6 wherein said region of reduced material is a gap having sufficient longitudinal dimension to prevent said blade member from pressing excessively against said predetermined body.9. The method of claim 1 wherein a plurality of angled stiffening members are disposed within said blade member and arranged to substantially reduce the tendency for said blade member to experience excessive buckling along said predetermined longitudinal dimension of said channel shaped contour.10. The method of claim 1 wherein a plurality of stiffening members are disposed within said blade member and arranged in a substantially staggered manner to substantially reduce the tendency for said blade member to experience excessive buckling along said predetermined longitudinal dimension of said channel shaped contour.11. The method of claim 10 wherein said blade member has a lengthwise alignment and at least one of said plurality of stiffening members is oriented at an angle to said lengthwise alignment.12. The method of claim 1 wherein two elongated stiffening members are connected to said blade member near said outer side edges, said elongated stiffening members having at least one notch.13. The method of claim 12 wherein said elongated stiffening members are formed within a thermoplastic material having a significantly high modulus of elasticity at said notch.14. The method of claim 12 wherein said notch is near said root portion.15. The method of claim 12 wherein said notch is near said base.16. The method of claim 1 wherein two elongated stiffening members are connected to said blade member near said outer side edges, said elongated stiffening members having an upper surface portion and a lower surface portion, said upper surface portion having a upper surface notch, said upper surface notch having an upper notch longitudinal dimension and an upper notch vertical depth, the ratio between said upper notch longitudinal dimension and said upper notch vertical depth being at least 3 to 1.17. The method of claim 16 wherein said ratio is not less that 4 to 1.18. The method of claim 16 wherein said lower surface portion of said elongated stiffening members have a lower surface notch having a lower notch longitudinal dimension and a lower notch vertical depth, said lower notch longitudinal dimension being different than said upper notch longitudinal dimension.19. The method of claim 16 wherein said lower surface portion of said elongated stiffening members have a lower surface notch having a lower notch longitudinal dimension and a lower notch vertical depth, said lower notch vertical depth being different than said upper notch vertical depth.20. The method of claim 1 further providing at least one elongated stiffening member connected to said blade member, said at least one elongated stiffening member having an upper surface notched portion and a lower surface notched portion, said upper surface notched portion having a predetermined upper notched shape, said lower surface notched portion having a predetermined lower notched shape, said predetermined lower notched shape being different than said predetermined upper notched shape.21. The method of claim 1 further providing at least one elongated stiffening member connected to said blade member, said at least one elongated stiffening member having an upper surface notched portion and a lower surface notched portion, said upper surface notched portion having a predetermined upper notched size, said lower surface notched portion having a predetermined lower notched size, said predetermined lower notched size being different than said predetermined upper notched size.22. The method of claim 21 wherein said upper surface notched portion has a predetermined upper notched vertical depth and a predetermined upper notched longitudinal dimension, said lower surface notched portion having a predetermined lower notched longitudinal dimension and a predetermined lower notched vertical depth, said predetermined lower notched longitudinal dimension being different than said predetermined upper notched longitudinal dimension.23. The method of claim 21 wherein said upper surface notched portion has a predetermined upper notched vertical depth and a predetermined upper notched longitudinal dimension, said lower surface notched portion having a predetermined lower notched longitudinal dimension and a predetermined lower notched vertical depth, and said predetermined lower notched vertical depth being different than said predetermined upper notched vertical depth.24. The method of claim 1 further providing at least one elongated stiffening member connected to said blade member, said at least one elongated stiffening member having an upper surface notched portion and a lower surface notched portion, said upper surface notched portion having a predetermined upper notched vertical depth and a predetermined upper notched longitudinal dimension, said lower surface notched portion having a predetermined lower notched longitudinal dimension and a predetermined lower notched vertical depth, the ratio between said predetermined upper notched longitudinal dimension and said predetermined upper notched vertical depth along said upper surface notched portion being at least 3 to 1.25. The method of claim 24 wherein said ratio is not less that 4 to 1.26. The method of claim 24 wherein said ratio is not less that 5 to 1.27. The method of claim 24 wherein said ratio is not less that 7 to 1.28. The method of claim 24 wherein said ratio is not less that 10 to 1.29. The method of claim 1 further providing at least one elongated stiffening member connected to said blade member, said at least one elongated stiffening member having an upper surface notched portion and a lower surface notched portion, said upper surface notched portion being arranged to create a different resistance to expanding during use than said lower surface notched portion.30. A method for providing a propulsion hydrofoil, comprising:(a) providing said hydrofoil with a blade member connected to a predetermined body, said blade member having an attacking surface, a lee surface, outer side edges, a root portion near said predetermined body and a free end portion spaced from said predetermined body, said blade member having a predetermined length between said root portion and said free end portion, said blade member having a longitudinal midpoint between said root portion and said free end portion, said blade member having a first half blade portion between said root portion and said longitudinal midpoint and a second half portion between said longitudinal midpoint and said free end portion, said blade member having sufficient flexibility to bow between said outer side edges to form a longitudinal channel shaped contour having, said longitudinal channel shaped contour extends from said free end portion toward said root portion to base of said longitudinal channel shaped contour, said base being located a predetermined distance from said predetermined body, said longitudinal channel shaped contour having a predetermined longitudinal dimension between said free end portion and said base; (b) providing said first half blade portion of said blade member with sufficient flexibility to experience a predetermined lengthwise deflection from a predetermined neutral orientation to a predetermined reduced lengthwise angle of attack around a transverse axis during use, said transverse axis being located within said first half portion of said blade member; (c) providing said blade member with sufficient spring-like tension during said predetermined lengthwise deflection so as to permit said blade member to experience a significantly strong snapping motion from said predetermined lengthwise deflection toward said predetermined neutral position; (d) controlling the build up of longitudinally directed compression forces within said blade member sufficiently to permit said predetermined longitudinal dimension of said channel shaped contour to extend over a majority of said predetermined length of said blade member as said channel shaped contour experiences said predetermined lengthwise deflection to said predetermined reduced lengthwise angle of attack during use; and (e) providing at least one elongated stiffening member connected to said blade member, said at least one elongated stiffening member having an upper surface notched portion and a lower surface notched portion, said upper surface notched portion having a predetermined upper notched size, said lower surface notched portion having a predetermined lower notched size, said predetermined lower notched size being different than said predetermined upper notched size. 31. The method of claim 30 wherein said blade member is arranged to have sufficient flexibility along said predetermined longitudinal dimension to permit said blade member to form an S-shaped sinusoidal wave during the inversion portion of a reciprocating propulsion stroke during use, said S-shaped sinusoidal wave being sufficient to increase the efficiency of said hydrofoil.32. The method of claim 30 wherein said upper surface notched portion has a predetermined upper notched vertical depth and a predetermined upper notched longitudinal dimension, said lower surface notched portion having a predetermined lower notched longitudinal dimension and a predetermined lower notched vertical depth, said predetermined lower notched longitudinal dimension being different than said predetermined upper notched longitudinal dimension.33. The method of claim 30 wherein said upper surface notched portion has a predetermined upper notched vertical depth and a predetermined upper notched longitudinal dimension, said lower surface notched portion having a predetermined lower notched longitudinal dimension and a predetermined lower notched vertical depth, and said predetermined lower notched vertical depth being different than said predetermined upper notched vertical depth.34. The method of claim 33 wherein the ratio between said predetermined upper notched longitudinal dimension and said predetermined upper notched vertical depth along said upper surface notched portion being at least 3 to 1.35. The method of claim 34 wherein said ratio is not less that 4 to 1.36. The method of claim 34 wherein said ratio is not less that 5 to 1.37. The method of claim 34 wherein said ratio is not less that 7 to 1.38. The method of claim 34 wherein said ratio is not less that 10 to 1.39. The method of claim 30 wherein said upper surface notched portion has a predetermined upper notched shape, said lower surface notched portion has a predetermined lower notched shape, said predetermined lower notched shape being different than said predetermined upper notched shape.40. The method of claim 30 wherein said upper surface notched portion is arranged to create a different resistance to expanding during use than said lower surface notched portion.