WO2015089568A1

WO2015089568A1 - A swim fin

Info

Publication number: WO2015089568A1
Application number: PCT/AU2014/001152
Authority: WO
Inventors: Ian HOGBEN
Original assignee: Hogben Ian
Priority date: 2013-12-19
Filing date: 2014-12-19
Publication date: 2015-06-25

Abstract

A swimming fin (1) including a body (2) for receiving at least a portion of a foot of a swimmer is disclosed. In an embodiment, the body (2) of the swimming fin (1) includes an anterior portion (2a) from which there depends at least one dorsal (20) or plantar shake (30) which extends laterally as it extends distally along the anterior portion so that in use,, as the swimmer moves their associated leg in an anterior direction in the water, the or each stroke creates a hydrodynamic force which urges the foot to rotate inwardly.

Description

A SWIM. FIN

[0001] This application claims priorit -from Australian Provisional Patent Application No. 2013904970 entitled "A Swim Fin" filed on 19 December 2013, the contents of which are to be taken as incorporated .herein by this reference.

TECHNICAL FIELD

[0002] The present invention relates to a swimming fin (or swim fin).

BACKGROUND

[00031 Swimmers wishing to swim faster or reduce associated fatigue should seek to reduce the drag created by their body as they move through the water.

[0004] The freestyle stroke, backstroke and butterfly all comprise kicking component which, if performed incorrectly, increases drag and slows the swimmer, in contrast, correct technique increases efficiency (i.e. reduces the effort required to swim) and increases speed by increasing forward propulsion and reducing dra by raising the swimmer's hips and legs and pointing the toes, thus improving the streamline position of the swimmer's body. However, a significant hurdle to learning correct kicking technique is that it is not intuitive.

[0005] It is against this background and the problems and difficulties associated therewith that the present invention has been developed. f 00061 Certain objects and advantages of the present invention wil t become apparent from the following description, taken in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed.

SUMMARY

| (K)07j For the purpose of this specification, distal means farther from the swimmer's body, proximal means closer to their body, medial means toward the centre line (or sagittal plane) of their body, and lateral means away from the centre line of their body. Moreover, dorsal refers to the top of the swimmer's foot, plantar refers to the bottom of their foot, anterior refers to the front of the swimmer's body, and posterior refers to the back of their body. [0008] Accordin to a first aspect, there is provided a swimming fin comprising a body for receiving at least a portion of a foot of a swimmer, the body compris ing art an terior portion from which there depends at least one dorsal or plantar strake which extends laterally as it extends distally along the anterior portion so that in use, as the swimmer moves their associated kg (i.e. associated with the foot) in an anterior direct-Oft in the water, the or each strake creates a hydrodynamic force which urges the foot to rotate inwardly (that is, towards the centreline of the swimmer). The rotation of the foot ma involve a lateral rotation about the ankle and/or it may involve an inward rotation of the leg from the hip joint, with either or both being attributable to the hydrodynamic force on. at least the dorsal strakes during the "down" stroke of the kicking action. In this respect, an inward rotation of the leg is a rotation of the right ieg in the counter-clockwise direction when viewed from the swimmer's perspective, and rotatio of the left leg in the clockwise direction when viewed from the swimmer's perspective.

[0009] By way of explanation, a strake, like a fin, is an appendage to a larger body which can be used to produce lift or thrust, or provide the ability to steer or stabilise motion while traveling in water, air or other fluid media.

[001 ] In one form, the swim fin further includes a lateral fin extending anterior of the anterior portion of the body thereof. In use, as the swimmer moves their associated leg in an anterior direction in the water, the lateral fin creates a hydrodynamic force which urges the foot toward a plantar flexion and inversion. j 00 i 1.1 Plantar flexion is the pointing of the toes, i.e. increasing the angle between the front part of the foot and the shin. Inversion of the foot is the movemen t of the sole of the foot toward the median (or sagittal) plane- of the swimmer, hi other words, inversion of the foot involves an extension of the lateral aspect of the ankle from the lateral malleolus (lateral ankle bone) to the lateral calcaneus (bone of the heel), thus tensioning the ealcaneofubular ligament. The combined effect of plantar flexion of the foot plus the inversion of the foot creates a slight twisting effect and a foot position known as supination. f 0012] According to a second aspect, there is provided a swimming fin comprising a body for receiving at least a portion of a foot of a swimmer, the body comprising an anterior portion from which there depends at least one dorsal or plantar strake which extends laterally as it extends distally alon the anterior portion, and a lateral fin extending anterior of the anterior portion of the body thereof so that in use, as the swimmer moves their associated leg in an anterior direction in the water, the or each strake creates a hydrodynamic force which urges the foot to rotate inwardly, and the lateral fin creates a hydrodynamic force whic urges the foot towards plantar flexion and inversion. j 0013 ] In one form, the or each strake extends from the anterior portion of the swim fin body to the lateral fin thereof,

[0014] in one form, the or each strake terminates at or near the edge of the lateral fin. f 00 Ϊ 5| in one form, the swim fin includes at least one dorsal strake, and one plantar strake.

[ 0016] la one form, the swim fin includes a plurality of spaced apart dorsal strikes.

[001.7] In one form, the swim fin includes a plurality of spaced apart plantar strakes.

[0018 ] in one form, in an alternative, the or each plantar strake extends cUstaily only. That is to say, the or eac plantar strake does not extend laterally as it extends distally.

1001 ] In one form, in an alternative, the or each plantar strake extends at angle ranging from one matching the angle of the dorsal strakes, through to one aligned with the sagittal or mid-line plane of the foot.

[0020] In one form, in an alternative, the angle at which the or each strake extends can be adjusted and se to provide different flow characteristics, as required by the swimmer or their coach.

[0021 ] In one form, the or each strake can be interchanged with strakes adapted to provide different flow characteristics (such as by being any one or more of a different length, height, thickness or shape), as required by the swimmer or their coach.

[0022 ] In one form, the lateral fin can be interchanged with a lateral fin adapted to provide different flow charac teristics (such as by being an one or more of a different length, height, thickness or shape), as required b the swimmer or their coach.

[0023 ] The above mentioned adjustment features could be incorporated by way of the strake and/or lateral fin comprising one or more attachment pins or lugs, and the fin body comprising one or more holes for receiving the pin(s) or lug(s).

[0024] In one form, the or each dorsal strake guides the foot during an anterior leg movement (i.e. that is, during the. "downward" action of a kicking cycle).

[0025 ] In one form, the or each plantar strake guides the foot during a posterior leg movement (that is, during the "upward" action of the kicking cycle). [0026] Accordin to a third aspect, there is provided a pair of the above described swimming tins, the pair comprising a swimming fin for a left foot of the swimmer, and a swimming .fin for a right foot of the swimmer.

[ 0027] in one form, the body of the swimming fin is shaped like a shoe, and includes an opening for receiving the foot of the swimmer. I one form, in an alternative, the anterior portion of the body includes an opening for receiving the foot of the swimmer, and the body further includes a heel Strap for retaining the anterior portion on the foot of the swimmer.

[0028] According to another aspect there is provided a swimming fm including:

a body for receiving at least a portion of a foot of a swimmer, the body including an anterior portion;

at least one dorsal or plantar stroke depending from the anterior portion of body, the at least one dorsal or plantar strake extending laterally as it extends distaily along the anterior portion; and

a. lateral fin extending anterior of the anterior portion of the body.

(0029] Preferably, the at least one dorsal or plantar strake includes plural stakes aligned in a parallel arrangement substantially entirel along their length. f 0030] In some embodiments, the body includes a foot-shaped upper surface. The at least one dorsal or plantar strake may depend from a toe region of the anterior portion of the foot-shaped upper surface. 00311 A detailed description of one or more embodiments of the invention is provided below along with accompanying figures that illustrate by way of example the principles of the in vention. While the invention is described in connection with such embodiments, it should be understood that the invention is not limited to any embodiment. On the contrary, the scope of the invention is limited onl by the appended claims and the invention encompasses numerous alternatives, modifications and equivalents. For the purpose of example, numerous specific details are set forth in the following description in order to provide a thorough unders tanding of the present invention.

[0032] The present invention may be practiced according to tine claims without some or all of these specific detail s. For the purpose of clarity, technical materi al that is known in the technical fields related to the invention has not been described in detail so that the present invention is not unnecessarily obscured. BRIEF DESCRIPTION OF DRAWINGS

[0033] Embodiments of the present invention will be discussed with reference to the accompanying drawings wherein:

£0034] Figure 1 is an. upper side (dorsal) view of a swimming fin according to a first embodiment of the invention;

[ 0035] Figure 1A is an upper side vide of a pair of swimming fras according to an embodiment of the present invention;

{0036] Figure 2 is an underside (plantar) view of the swimming fin of Figure 1 ; [0037] Figure 3 is a lateral upper side view of tire swimming fin of Figure f ;

[0038] Figure 4 is a lateral upper side view of a swimming fin according to a second embodiment of the invention;

[ 0039 ] Figure 5 is an upper side (dorsal) view of a swimming fin accordi ng to a further embodiment of the invention;

[0040] Figure 6 is a underside (plantar) view of the swimming fin of Figure 5; j 0041 1 Figure 7 is a cross-sectional view through the swimming fin of Figure 5 taken along line A-A; f 0042] Fignre 8 is a cross-sectional view through the swimming fin of Figure 5 taken along line E-E; j 0043] Figure 9 is a cross-sectional view through the swimming fin of Figure 5 taken along line D-D;

[0044] Figure 10 is a cross-sectional vie w through the swimming fin of Figure 5 taken along line G-G;

[0045 ] Figure. 11 is a lateral upper side view of the swimming fin of Figure 5 ;

[0046] Figure 12 is a lateral underside view of the s wimming fin of Figure 5;

[0047] Figure 13 is a lateral upper side vie of a sw imming fin according to a further embodiment of the invention;

[0048] Figures 1 A through I4C illustrate a left side vie of the swimming fin in use; j 0049 ] Figures 15A through 15C illustrate flow patterns of the swimming fm in use; [0050] Figures 16A throug 16D illustrate a right foot swimming fin in use; and J ^'0051 ] Figures 17 A through 1 ?H illustrate a left foot swimming fin in use.

[00521 In the following description, like reference characters designate like or corresponding parts throughout the figures,

DESCRIPTION OF EMBODIMENTS

[0053 ] Referring now to Figure 1, there is shown a swimming fin I comprising a body 2 shaped like a shoe and comprising an opening 4 for receiving a foot of a swimmer, and a sole 5.

[0054] The body 2 includes an anterior portion 2a from which there depends a lateral fin 10 extending anterior (i.e. forward) of and lateral. (i.c. away from the centre line ML of the swimmer's body) to me anterior portio 2a of the body 2. This lateral fin 10 extends from the anterior portion 2a of the body 2 at approximately half a height of a toe portion thereof and from of the medial side of the big toe, distally, and laterally around to a mid-lateral aspect of the foot. As shown in Figure I A, an inner lateral edge 3 (that is, the medial edge of th lateral fm 10) of the lateral fin 10 is shaped so that in use the inner lateral edge of the left and right fins are less likely to collide during kicking. As is shown in Figure 1 A. in some embodiments, the inner lateral edge 3 is substantially parallel with the dorsal strakes 30.

[0055 ] The swimming fi 1 further includes a plurality of (four in this case) dorsal strakes 20, each of which extends from an upper side of the anterior portion 2a to the lateral fm 1 , and laterally (i.e.

outwardly) as they extend distally (i.e. fbrwardly) along the anterior portion 2a. In the present case, the upper side of the anterior portion 2a includes a foot-shaped upper surface.

[0056] In use, the dorsal strakes 20 cause a laminar flow between each strake 2.0 to an approximate level of the height of the strakes 20. Above the level of the height of the strakes 20, water is not constrained b the strakes 20, and thus flows off the dorsal foot in a. similar pattern to that of a bare foot during an anterior kick. In use, the dorsal strakes 20 h w the effect of directing the foot into an inwardly rotatin supine kick with less stretch on ligaments and muscles providing a more natural feel and ma contribute to a reduction in the occurrence of cramping and strain injuries.

[0057 J With reference to Figure 2 it can be seen that the swimming fin 1 further includes a plurality of (four in this case) plantar strakes 30, each of which extends from an underside of the anterior portion 2a to the lateral fin 10, and laterally as they extend distally along the anterior portion 2a. j 0058 ] Referring now to Figure 4, where there is illustrated a swimming fm la, which differs from swimming fin 1 in as much as it includes dorsal strake 20a which are not curved along their leading edge like the strakes 20 of swimming fin 1 , but straigh t edged.

10059 ) Moreover, while all the lateral fin 10 and all of the strakes 20 are illustrated as being perfectly straight lengthwise, these could be curved lengthwise if this gave the desired flow characteristics.

[0060] Referring now to Figures 5 through 12, where there is illustrated a swimming fin lb, which differs from swimming fin j in as much as it includes plantar strakes 30 which extend distally only. That is to say. the plantar strakes 30 do not extend laterally as they extend distally.

[0061} breach of the above described embodiments, the swim fin 1 , 1 a and lb is integrally formed from an elastomeric material, such as a natural or synthetic rubber, or silicon. Construction is not so limited however, for instance* the body 2 could be made of a dissimilar material to the lateral fin 10 and the strakes 20. What is more, the lateral fin 10 and the strakes 20 may be separable from the body 2 so that these may be swapped for a. different lateral fin and/or strakes as. the swimmer improves.

[ 0062-1 With reference to Figures 14 through 17, it can be seen how in use, as the swimmer kicks their associated leg (i.e. the teg associated with the foot wearing the swim fin) in an anterior direction in the water, water pressure on the dorsal (or upper) side of the lateral fin 10 creates a hydrodynamic force which urges the foot towards a plantar flexion (i.e. a pointing of the toes) and inversion. Simultaneously, water pressure on. the lateral (or outer) side of the dorsal strakes 20 creates a hydrodynamic force which urges the foot to rotate inwardly (i.e. movement of the sole toward the median (or sagittal) plane), as a result of either inwar d rotation of the kg from the hip and/or rotation about the ankle.

[0063] The resultant positioning and alignment of the foot caused by the hydrodynamic forces created fay the fin 10 as the swimmer kicks their leg i the anterior direction may produce a more efficient and more powerful kick This is because the combined inward rotation, inversion and plantar flexion, presents a greater foot surface that effects a more caudally directed pressure on the water, thereby botli improving the power of the kick and also improved efficiency of the kick action. ^'0064^'l It is to be noted inversion of the foot may be due to the hydrodynamic force created by the fin 1 in use causing a lengthening of the lateral belly of the gastrocnemius muscle, the peroneus brevis muscle, the soleus muscle and the peroneus longus muscle. It is to be noted that when the foot is in plantar flexion without inversion, these muscle are contracted and often become subject to cramp. Accordingly, the use of the swim fins 1 may reduce or prevent cramp of these muscles in swimmers. [0065] Combined inversion and plantar flexion of the foot may also relieve the muscular contraction of the extensor digitum brevis muscle as the action relies .on passive action rather than muscular contraction in the foot and therefore may minimise or preven t cramping in the plantar aspect of the foot when using_, training fins,

[0066] As can be seen in Figures 16A through 16D, for a righ t foot inward rotation of the foot will be counter-clockwise whe viewed from the swimmer's perspecti e. Figure 16D shows the effect if a foot is over-imvardly rotated, in whic ease water pressure on the dorsal strokes may urge the foot back to the position illustrated in Figure 161⁾. As best shown in Figures 14A through 14C, for a lef foot, rotation of the foot will be clockwise when viewed from the swimmer's perspective. In the example shown in 14A through 14C, Figure 1.4 A depicts the left foot in a normal "straight" position prior to commencing a downward kick. As shown in Figure 14B with as downward pressure is applied the foot assumes a supine position, with plantar flexion (i.e. pointing of the toes) and inversion of the ankle. As shown in Figure 1.4C, as the kick proceeds, in addi tion to supination of the foot, an inward rotation of the leg from the swimmers hip joint is introduced. This inward rotation of the leg is due, at least in part, to hydrostatic forces on the dorsal strokes.

[0067] In the event that inward rotation of the foot becomes too pronounced, a illustrated in Figure 16D, water pressure on the media! (or inner) side of the dorsal strokes 20 will urge a slight outward rotation until the desired degree of rotation, and thus alignment, is reached (see Figure 16C).

1006 1 Referring to Figure 1 , it can be seen that a section of the lateral fin 1 extends from a dorsolateral portion of the body 2 and includes an upper surface which forms a continuum with the body 2, It will of course be appreciated that it is not essential that the lateral fin 10 extends from a dorso-lateral portion of the body 2 since in some embodiments the lateral fin 10 may extend from the sole of the body 2. Nevertheless, it is preferred that the lateral fin 10 includes at least a section which extends from a dorso-lateral portion of the body 2, and mcludes an upper surface which forms a continuum with the body 2, as this arrangement may allow for improved hy.drodynamic flow off a top region of the swimmer's foot which is similar to the natural contour and thus flow from a bare foot, as is more clearly show in Figures 15A and 15C_ In this respect, Figure 15 A depicts a water flow direction (shown as dashed arrows) between the strokes which tend to orientate the swimmer's foot in use, whereas Figure 15B depicts wafer flow direction (shown as dashed arrows) in a region above the level of the strokes. Figure 15C depicts the combined water flo directions depicted in Figure 15A and Figure 1 B.

[0069] Referring now to Figures 17A to 17 E illustrate a full kick cycle for a left foot viewed from the rear. As shown, as the swimmer kicks their leg in the posterior direction, the plantar strokes 30b act to urge eversion of the foot so that the natural alignment of an anterior portion of the foot with respect to the heel is restored. In particular. Figure I.7A depicts an upper most position of the kick cycle, Figure 17B depicts a transition position during the down kick in which the foot becomes supine and commences inward rotation. Figure 1.7C and 17D depicts a supine position with inward rotation of the foot {note that in this position the dorsal strakes 20 are aligned so as to have corrected the alignment of the foot on the down kick). Figure 17.E depicts the upwardly directed (that is, the u kick) part of the kick cycle with the foot coming back into alignment with the heel due, at least in part, to the interaction of flow of water with the plantar strakes. Figures 17F to 17H depict the path of movement of points identified as "A",_. "B" and "C^* over the kick cycle. j 00701 The result of training with the swim fins provides stretching of ankle ligaments that result in an increased likelihood of a correct kicking angle when not wearing the fins. Repeated training sessions reduce the likelihood of the loss of gained ankle flexibility. f 0071 J The swimming fin according to the present invention will be of use to swimmer's at all levels to reduce drag caused by poor foot angle when kicking, and reducing the effort and energy required to produce a kick that will, keep the swimmer's legs higher in the water (to also reduce drag), and over all, improve swimming technique, efficiency and power, while possibl reducing occurrences of foot and leg cramps.

[0072] Throughout the specification and the claims that follow, unless the context requires otherwise, Ac words "comprise" and "include'^'' and variations such as "comprising" and "including" will be understood to imply the inclusion of a stated integer or group of integers, but not the exclusion of any other integer or group of integers. j 0073] The reference to any prior art in this specification. is not, and should not be taken as, an

acknowledgement of any form of suggestion tha t such prior art forms part of the common general knowledge.

[0074] it will be appreciated by those skilled in the art that the invention is not restricted in its use to the particular application described. ^"Neither is the present invention restricted in its preferred embodiment with regard to the particular elements and/or features described or depicted herein. It will be appreciated that the invention is not limited to the embodiment or embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing from the scope of the invention as set forth and defined by the following claims

Claims

1. A swimming fin including a bod for receiving at least a portion of a foot of a swimmer, the body including an anterior portion from which there depends at least one dorsal or plantar .strake which extends laterally as it extends distally along the anterior portion so thai in use, as the swimmer moves their associated leg in an anterior directio in the water, the or each strake creates a hydrodynamic force which urges the foot to rotate inwardly,

2. The swimming fin of claim 1, further including a lateral fin extending anterior of the anterior portion of the body thereof so that in use, as the swimmer moves their associated leg in an an terior direction in the water, the lateral fin creates a hydrodynamic force which urges the foot towards plantar flexion, and inversion.

3. A s wimming fin including a body for receiving at least a portion of a foot of a swimmer, the body including an anterior portion from which there depends at least one dorsal strake which extends laterally as it extends distally along the anterior portion, and a lateral fin extending anterior of the anterior portion of the body thereof so that m use, as the swimmer ^'mo es their associated leg i an anterior direction in the water, the or each strake creates a hydrodynamic force which urges the foot to rotate inwardly, and the lateral fin creates a hydrodynamic force which urges the foot towards plantar flexion and inversion.

4. The swimming fin as in any one of the preceding claims, wherei the or each strake extends from the anterior portion of the swim fin body to the lateral fin th ereof.

5. The swimming fin of claim 4, wherei the or each strake terminates at or near an edge of the lateral fin.

6. The swimming fin as in any one of the preceding claims, wherein the swim fin includes at least one dorsal strake, and one plantar strake,

7. The swimming fi as in any one of the preceding claims, wherein the swim fin includes a plurality of spaced apart dorsal strakes.

8. The swimming fin as in any one of the preceding claims, wherein the swim fin includes a plurality of spaced apart plantar strakes,

9. The swimming fin as in any one of claims 6 through 8, wherein the or each dorsal strake guides the foot during a posterior leg movement.

I.0. A pair of the swimming fins of any one of the precedin claims, the pair includin a swimming fin for a left foot of the swimmer, and a swimming fin for a right foot of the swimmer.

I I . A swimming fin including:

a body for recei ving at least a portion of a foot of a swimmer, the body including an anterior portion; at least one dorsal or plantar strake depending from the anterior portion of body, the at least one dorsal or plantar strake extending laterally as it extends distalfy along the anterior portion; and

a lateral fin extending anterior of the anterior portion of the body.

12. A swimming fin according to claim 1 1 , wherein the at least one dorsal or plantar strake- includes plural strakes aligned in a parallel arrangement substantially entirely along their length.

13. A swimming fin according to claim 12 or 13, wherein the body includes a foot-shaped tipper surface.

14. A swimming fin according to claim 13, wherein the at least one dorsal or plantar strake depend from a toe region of the anterior portion of the foot-shaped outer surface.