WO2017044328A1

WO2017044328A1 - Selachimorphic swim fins

Info

Publication number: WO2017044328A1
Application number: PCT/US2016/049150
Authority: WO
Inventors: Alex HANSEN
Original assignee: Hansen Alex
Priority date: 2015-09-11
Filing date: 2016-08-26
Publication date: 2017-03-16

Abstract

Selachimorphic swim fins have high aspect ratios, are asymmetric and have high leg attachment angles. Selachimorphic swim fins enable swimmers to propel themselves through water with ease and efficiency.

Description

Selachimorphic Swim Fins

Related Applications

[01] This application claims priority to and the benefit of US Provisional Application Number 62/283,779, "Selachimorphic Swim Fins" filed on 09/11/2015 and US Provisional Application Number 62/387,989, "Selachimorphic Swim Fins" filed on 01/12/2016, both of which are incorporated herein by reference.

Technical Field

[02] The present technology relates to swim fins for swimming and diving.

Background

[03] Swim fins are essential for scuba diving and snorkeling, and are fun when swimming for any reason. Swim fins enable a person to swim much faster than they could otherwise. In addition to recreational use, swim fins have applications in military and commercial diving operations. A conventional swim fin is illustrated in Fig. 1A.

[04] Early swim fins were first conceived centuries ago and modern swim fins were first demonstrated in 1914 by de Corlieu. Since then many different designs have appeared.

However, there is still room for improvement and therefore what is needed are swim fins that help a person move through water ever more quickly and easily.

Brief Description of the Drawings

[05] Fig. 1A shows a conventional swim fin.

[06] Fig. IB shows a selachimorphic swim fin with no medial blade. [07] Fig. 2 shows a pair of selachimorphic swim fins worn by a swimmer. [08] Figs. 3A - 3C show selachimorphic swim fins having various leg angles.

[09] Figs. 4A and 4B show selachimorphic swim fins having various leg angles. The fins shown in Figs. 4A and 4B do not have trailing edge notches.

[10] Fig. 5 shows a selachimorphic fin worn by a swimmer.

[11] Figs. 6A - 6D show a set of 40° leg angle selachimorphic fi ns having various aspect ratios. The fins shown in Figs. 6A - 6D do not have media l fin blades.

[12] Figs. 7A - 7E show a set of equal area selachi morphic fins having various leg angles. The fins shown in Figs. 7A - 7E do not have media l fin blades.

[13] Fig. 8 shows an exa mple selachimorphic fin with mid-foot attachment.

[14] Fig. 9 shows an exa mple selachimorphic fin with toe attachment.

[15] Fig. 10 shows a n exa mple selachimorphic fin with toe attachment.

Detailed Description

[16] Selachimorphic swim fins enable a swi mme r to move through water easily a nd efficiently.

[17] Fig. IB shows an example of a selachimorphic swim fi n. Compared to the conventional fin of Fig. 1A, the selachimorphic fin has a high aspect ratio and a la rge fin span, b.

[18] The selachimorphic fin of Fig. IB looks like it would not work very well. However, in- water testing has shown that the twisti ng force on a wearer's ankle is much sma ller than expected a nd the fin provides good thrust in the water. A sma ll medial fin blade may be added to further reduce twisting.

b²

[19] Selachimorphic swim fins have high aspect ratios. Aspect ratio is defined by A R—— where b is the fin span as shown in Figs. 1, 6 a nd 7, and S is the fi n a rea as shown in Figs. 6 and 7. Selachimorphic swim fins have aspect ratio greater than one. The aspect ratio of the selachimorphic fin in Fig. IB is about 2.3, while the aspect ratio of the conventional fin in Fig. 1A is only about 0.7.

[20] Selachimorphic swim fins are asymmetric. Selachimorphic swim fins have a large lateral fin blade and a small medial fin blade, or no medial fin blade. The small or non-existent medial fin blade makes selachimorphic swim fins compatible with a natural, left-right flutter kicking motion.

[21] Selachimorphic swim fins have a high leg-attachment angle. The leg attachment angle, i.e. the angle between the leading edge of the lateral fin blade and the leg axis or boot axis is between about 20 degrees and about 70 degrees, with leg angles between about 30 degrees and about 50 degrees being preferred.

[22] Selachimorphic swim fins have a lateral fin blade with leading edge reinforcement or a mid-chord stiffener.

[23] Each of these features of selachimorphic swim fins is illustrated in the figures.

[24] Fig. 2 shows a pair of selachimorphic swim fins worn by a swimmer. In Fig. 2, each selachimorphic swim fin includes an optional notch in the trailing edge of its lateral fin blade. The medial fin blades are small enough to allow the swimmer to use a natura l flutter kicking motion.

[25] Figs. 3A - 3C show selachimorphic swim fins having various leg angles. Higher leg angles are preferred for fast swimming. Leg angle is measured between the leading edge of the lateral fin blade and the boot axis or the axis of a wearer's lower leg as shown in the figures. The fins of Figs. 3A - 3C have leg angles of about 60, 45 and 20 degrees respectively.

[26] The fins in Figs. 3A and 3C include small medial fin blades and their lateral fin blades have a notch in the trailing edge. The fin in Fig. 3B does not have a medial fin blade and the trailing edge of its lateral fin blade does not have a notch.

[27] Figs. 4A and 4B show selachimorphic swim fins having various leg angles. The leg angle of the fin in Fig. 4A is about 50 degrees; in Fig. 4B it is about 60 degrees. The fins in Figs. 4A - 4B do not have a trailing edge notch. [28] Fig. 5 shows a selachimorphic fin worn by a swimmer. The fin is on the swimmer's left leg. In this example, the fin has a reinforcing stiffener. The stiffener is located between the leading and trailing edges of the fin. In the chord direction, it is located about 30% of the way from the leading edge to the trailing edge.

[29] The lateral fin blade is the part of the fin on the lateral side of the boot axis; the medial fin blade is the part of the fin on the medial side of the boot axis. The fin boot axis is parallel to wearer's lower leg axis in normal use. Fin span, b, is measured perpendicular to the boot axis; see Figs. 1, 6 and 7.

[30] Figs. 6A - 6D show a set of 40° leg angle selachimorphic fins having various aspect ratios. The fins shown in Figs. 6A - 6D do not have medial fin blades. Aspect ratio is defined by i)²

AR = where b is the fin span and S is the fin area as shown in the figure. Fin span is measured perpendicular to the fin boot axis. The fins in Figs. 6A - 6D do not have medial fin blades, but if they did the medial fin blades would increase both b and S for each fin.

[31] The table in the lower right part of Figs. 6A - 6D lists approximate values for the length (L), width (W), area (S), span (b) and aspect ratio (AR) for each of the fins in the figure. L, W, S and b are given in arbitrary units. The approximate aspect ratios for the fins in Figs. 6A - 6D are 1.4, 1.9, 2.6 and 2.7, respectively.

[32] Figs. 7A - 7E show a set of equal area selachimorphic fins having various leg angles. The fins shown in Figs. 7A - 7E do not have medial fin blades. Leg angle is measured between the leading edge of the lateral fin blade and the axis of the fin boot. The fins in Figs. 7A - 7E do not have medial fin blades, but if they did the medial fin blades would increase both b and S for each fin.

[33] The table in the lower right part of 7A - 7E lists approximate values for the area (S), span (b) and aspect ratio (AR) for each of the fins in the figure. S and b are given in arbitrary units. The area, S, of each fin is about the same. The approximate aspect ratios for the fins in Figs. 7A - 7E are 1.2, 1.9, 2.9, 4.1 and 5.2, respectively.

[34] Fig. 8 shows an example selachimorphic fin with mid-foot attachment. Many manufacturing methods exist that are suitable for making selachimorphic swim fins. Materials may be similar to, or the same as, those used to make conventional fins. Typical materials used in fin manufacturing include rubber, polyurethane and carbon reinforced plastics.

[35] The leading edge of the lateral fin blade is reinforced to make it stiffer. The trailing edge of the lateral fin blade is flexible.

[36] The small medial fin blade shown in the figure is optional. The fin in Fig. 8 has its fin blades attached in the mid foot region of the fin boot.

[37] Fig. 9 shows an example selachimorphic fin with toe attachment. The leading edge of the lateral fin blade is reinforced to make it stiffer. The trailing edge of the lateral fin blade is flexible.

[38] The small medial fin blade shown in the figure is optional. The fin in Fig. 9 has its fin blades attached in the toe region of the fin boot. This fin also has vortex generators.

[39] Fig. 10 shows an example selachimorphic fin with toe attachment. The lateral fin blade includes a stiffener located part way between the leading and trailing edges in the chord direction.

[40] The small medial fin blade shown in the figure is optional. The fin in Fig. 10 has its fin blades attached in the toe region of the fin boot.

[41] Selachimorphic swim fins have high aspect ratios, are asymmetric and have high leg attachment angles. Selachimorphic swim fins enable swimmers to propel themselves through water with ease and efficiency.

[42] The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the principles defined herein may be applied to other embodiments without departing from the scope of the disclosure. Thus, the disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[43] All elements, parts and steps described herein are preferably included. It is to be understood that any of these elements, parts and steps may be replaced by other elements, parts and steps or deleted altogether as will be obvious to those skilled in the art. [44] Broadly, this writing discloses at least the following: Selachimorphic swim fins have high aspect ratios, are asymmetric and have high leg attachment angles. Selachimorphic swim fins enable swimmers to propel themselves through water with ease and efficiency.

[45] The following table may help with interpreting the figures:

This writing also presents at least the following concepts:

1. A swim fin comprising : a boot having an axis that is parallel to a wearer's lower leg when worn; and a lateral fin blade having a leading edge, wherein : the leading edge of the lateral fin blade forms an angle with the boot axis of between 20 degrees and 70 degrees, and the swim fin has an aspect ratio greater than one.

2. The swim fin of Concept 1 wherein the leading edge of the lateral fin blade forms an angle with the boot axis of between 30 degrees and 50 degrees.

3. The swim fin of Concepts 1 or 2 wherein the leading edge of the lateral fin blade is reinforced.

4. The swim fin of Concepts 1, 2 or 3 wherein the lateral fin blade includes a stiffener between its leading and trailing edges.

5. The swim fin of any one of Concepts 1 - 4 wherein the lateral fin blade is attached to a mid-foot region of the boot.

6. The swim fin of any one of Concepts 1 - 4 wherein the lateral fin blade is attached to a toe region of the boot.

7. The swim fin of any one of Concepts 1 - 5 further comprising an asymmetric medial fin blade.

8. The swim fin of Concept 7, the medial fin blade being small enough so as not to interfere with a wearer's flutter kicking motion.

Claims

What is claimed is:

1. A swim fin comprising: a boot having an axis that is parallel to a wearer's lower leg when worn; and a lateral fin blade having a leading edge, wherein ; the leading edge of the lateral fin blade forms an angle with the boot axis of between 20 degrees and 70 degrees, and the swim fin has an aspect ratio greater than one.

2. The swim fin of Claim 1 wherein the leading edge of the lateral fin blade forms an angle with the boot axis of between 30 degrees and 50 degrees.

3. The swim fin of Claim 1 wherein the leading edge of the lateral fin blade is reinforced.

4. The swim fin of Claim 1 wherein the lateral fin blade includes a stiffener between its leading and trailing edges.

5. The swim fin of Claim 1 wherein the lateral fin blade is attached to a midfoot region of the boot.

6. The swim fin of Claim 1 wherein the lateral fin blade is attached to a toe region of the boot.

7. The swim fin of Claim 1 further comprising an asymmetric medial fin blade.

8. The swim fin of Claim 7, the medial fin blade being small enough so as not to interfere with a wearer's flutter kicking motion.