WO1992011176A1

WO1992011176A1 - Single swim fin for both feet

Info

Publication number: WO1992011176A1
Application number: PCT/US1990/007555
Authority: WO
Inventors: Robert B. Evans
Original assignee: Evans Robert B
Priority date: 1990-12-20
Filing date: 1990-12-20
Publication date: 1992-07-09

Abstract

A single swim fin which has a planar trapezoidal shaped flexible base (24) with a pair of symmetrical upwardly curved tips (30). A pair of foot retainers (34) are integrally located on the base at the rear and are slightly pointed inward. The retainers have a rearward opening (36) and a forward opening (38) of a size to secure each foot of a swimmer. A strap (40) with a stiffening sleeve (44) and buckler (46) hold each foot into the swim fin. The base is planar in the middle and tapers toward the outside edge. The tips are flexible enough so that they are responsive to a force urged against the upper surface, causing an arcuate shaped path curling away from the foot retainers creating a build-up of water pressure within the flexed surface, subsequently when the direction of travel is reversed a snapping action takes place producing a propelling force through the water.

Description

SINGLE SWIM FIN FOR BOTH FEET TECHNICAL FIELD

The invention pertains to the general field cf swim fins which are attached to a swimmer's feet tc improve propulsion through the water and more particularly to a single fin that fits on both feet and utilizes the snapping action of the swim fin tips.

BACKGROUND ART

Previously, many types of swim fins have beer used to provide an effective means to assist a person in propelling themselves through the water. A single fin has been the generally accepted method, with one fin on each foot, moving the feet in opposite directions to accomplish the forward thrust. Some approaches have employed both feet simultaneously duplicating a flipper or fluke, others simply attach two fins together either rigidly or hinged with little attention given to the action of the fin other than its resistance to the water.

A search of the prior art did not disclose any patents that read directly on the claims of the instant invention, however, the following U.S. patents were considered related:

PATENT NO. INVENTOR ISSUED

4,857,024 Evans 15 August 19E9

4,781,637 Oaires 1 November 1888

4,541,810 Wenzel 17 September 1995

3,987,509 Patterman 26 October 1976

3,934,290 Levasseur 27 January 1976 3,714,921 Gibson 6 February 1973

3,344,449 Grilli 3 October 1967 3,165,764 Christiansen 19 January 1965

2,172,938 Kahn 12 September 1 939 1,603,616 Long 19 October 1926

1,530,560 Heminger 25 March 1925

1,237,392 Schneider 21 August 1917

1,142,652 Wirsig 8 June 1915

Of particular relevance is the patent issued to Evans who is also the inventor of the present application, while this patent is for a single fin for an individual foot much of the same action of the fin is incorporated into this invention in combination, other elements are different enough as to make the combination distinguish over the inventors own prior art.

Oaires discloses a swimming fin having a foot pocket 102 with a hell end 104 and a toe end 106 for receiving the swimmer's feet in a spaced apart, side-by-side relationship, a hydrofoil fin 108 extending from the pocket at an angle defined by the soles of the swimmer's feet, and a rod 708 and a plate 710 to provide stiffening of the fin. A wall 114 divides the pocket 102 into left and right foot chambers 112 and. 110, respectively.

Wenzel also discloses a tail having a flipper 11, a foot-receiving pocket 14 that accommodates both feet of the user and straps 20,22 for securing the user's feet in the pocket 14. A resilient Y-shaped frame 15 made of metallic sheet or tubing material gives the flipper 11 its structural integrity. The frame 15 is covered, by a plastic webbing 17.

Patterman discloses a swimming tail consisting of left and right rubber flippers 12 and 1 4, respectively, and foot openings 28,30 having a toe end 34 and a heel end 36. Flippers 12,14 are identical in shape but are laid in a side-by-side relationship in opposite directions. Flippers 12,14 have an elongated. fin of teardrop cross-sectional shape which tapers to a point. The elongated fin of the left flipper 12 projects from the heel end 36, whereas that of the right flipper 14 projects from the toe end 34.

Levasseur discloses a full-body swimming suit having a single foot fin with a large fluke and two openings leading to foot pockets separated by a cushion. The foot fluke portion 2 has a broad, laterally extended fluke 12 with a distal edge 14. Holes 16 let water out of foot pockets in the foot-receiving portion 13. Port openings 20 connect diagonal passageways with lower rearward ports 22.

Gibson discloses a water float with paddle extensions. The float comprises a buoyant body 10 connected to a pair of buoyant paddles 12,14 by a hinge 24, and straps 30 for securing the user's feet in the paddles 12, 14. The space between paddles 12,14 may be spanned by a web 26 of flexible material.

Grilli discloses a one-piece swimsuit comprising a tubular sock, or bag-like structure terminating in a tail fin. The swimsuit is designed to be worn on the lower part of a person's body. The fin portion of the device at its proximal end is equipped with aligned pairs of through holes 42 in a pocket designed to accommodate the feet of the wearer. water pouring through the aligned perforations 42 in the pocket 24 and fin structure 30 provide additional propulsion energy and drive. Additionally, the distal portion of the fin comprises a plurality of spaced ribs 50 to provide reinforcement.

Christiansen discloses a detachable coupling for a swimming fin. The pertinent part of this art is a pair of swimming fins 10.11 that are detachably secured together in a side-by-side relationship by a clamp 18. The clamp is releasataly attached to the inner reinforcing ribs 12,13 :f the fins 10.11 respectively, It should be noted that the fin does not have straps to retain the swimmer's feet.

For background purposes and as indicative of the art to which the invention relates, reference may be made to the remaining cited patents of Wirsig, Schneider, Heminger, Long and Kahn.

DISCLOSURE OF THE INVENTION

The prior invention of the inventor described previously operates in a manner which is substantially opposite to that of the prior art devices.

Specifically, during the portion of a stroke which would be considered the power stroke by the prior art swim fins, that portion of the stroke would be considered the reset stroke. conversely, what traditionally is the reset stroke for the prior art swim fins is the power stroke for the present fin such that the swim fin of the present invention produces a propelling force during the portion of a swimmer's stroke when a swimmer's leg is moved from a position substantially parallel with that of the swimmer's body into a position where the feet are located below the swimmer's body.

It was found that by altering the entire approach to the improvement of swim fins, that using both feet into a single fin, instead of just one, the novelty of the snapping action of the prior invention could be combined with the use of both feet achieving new and unexpected results. Without this combination, no substantial improvement was made to the swim fin by simply adding a second foot retainer, as others have produced flippers or flukes using both feet for a considerable amount of time with little public acceptance. It is, therefore, the primary object of the invention to employ a single fin for a swimmer attaching both feet side-by-side into the fin using a pair of bridge type retainers and straps along with a flexible fin having sufficient resiliency and a cross-sectional area to allow the power stroke to be employed in conjunction with a snapping action of the tip of the fin.

An important object of the invention is further directed to the ease of use of the fin. As both feet are attached together, the swimmer's muscles are used in unison and the entire body is bowed and arched in a porpoise-like movement with the snap action of the tips creating additional thrust, particularly when both legs simultaneously push against the resistance of the water at the moment the tips are acutely bent. Also, the swimmer's movement is continually smooth and hydrodynamic as no eddy currents are created between the swimmer's feet, as normally occurs when a pair of fins are used. This flowing tranquil rhythm permits equivalent velocity in the water with less energy expenditure as the legs are not overcoming the directional differences and resistance describe:¹ previously.

Another object of the invention completely eliminates the problem of hitting the fins together when they pass by each other when individual fins are used. Normally, the swimmer's legs are placed apart, in order to not have this conflict necessitating a rather awkward angle. The use of a single fin overcomes these problems and places the feet almost together at a slight inward angle, allowing a comfortable and natural position of the feet and legs.

Still another object of the invention is directed to a fin that is smaller and lighter than two individual fins and. ultimately displaces the water, as there is only one peripheral edge instead of two. As the resistance to the water is based on area and shape, the leading edge of the single fin is considerably smaller, than a pair as if two were placed side-by-side, these contiguous surfaces could be eliminated completely in a single double footed fin.

Yet, another object of the invention is that the swim fin may be utilized without the necessity of a strap, or, if a strap is broken or becomes disconnected, the swim fin will remain on a swimmer's foot due to the direction of the force vectors urging the fin thereagainst during the power stroke.

Further, the swim fin has its foot receiving portion and its flexible fin portion formed of a resilient material which is molded into an integral one-piece molding of the resilient material.

These and. other objects and advantage of the present invention will become apparent from the subsequent detailed description of the preferred embodiment and the appended claims taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGURE 1 is a partial isometric view of the preferred embodiment looking from the top.

FIGURE 2 is a top plan view of the preferred embodiment.

FIGURE 3 is a right side elevation view of the preferred embodiment.

FIGURE 4 is a bottom view of the preferred embodiment.

FIGURE 5 is a left side elevation view of the preferred embodiment.

FIGURE 6 is a front view of the preferred embodiment. FIGURE 7 is a rear view of the preferred embodiment.

FIGURE 2 is a cross-sectional view taken along lines 8-8 Of FIGURE 2.

FIGURE 9 is a right side elevational view of the second embodiment with ribs.

FIGURE 10 is a bottom view of the second embodiment with ribs.

FIGURE 11 is a right side elevational view of the third embodiment with the tips straight.

FIGURE 12 is a right side elevational view of the fourth embodiment with the tips straight and ribs on the bottom surface.

FIGURE 13 is a cross-sectional view taken along lines 13-13 of FIGURE 10 depicting the ribs in the body.

FIGURE 14 is a cross-sectional view taken along lines 14-14 of FIGURE 2 depicting the foot retainers on the body.

FIGURE 15 is a cross-sectional view taken along lines 15-15 of FIGURE 2 depicting the body in the central portion.

FIGURE 16 is a cross-sectional view taken along lines 16-16 of FIGURE 2 depicting the tips.

FIGURE 17 is a pictorial representation of a swimmer's foot within the fin at the beginning of a power stroke.

FIGURE 18 is a pictorial representation of a swimmer's foot within the fin at the middle of a power stroke.

FIGURE 19 is a pictorial representation of a swimmer's foot within the fin at the end of a power stroke.

FIGURE 20 is a pictorial representation of a swimmer's foot within the fin at the beginning of a reset stroke. FIGURE 21 is a pictorial representation of a swimmer's foot within the fin at the middle of a reset stroke.

FIGURE 22 is a pictorial representation of a swimmer's foot within the fin at the end of a reset stroke.

REST MODE FOR CARRYING OUT THE INVENTION

The best mode for carrying out the invention is presented, in terms of a preferred, second, third and fourth embodiments,

In order to describe the complete relationship of the invention, it is essential that some description be given to the manner and practice of functional utility and description of the fins action relative to the water and the movement of the swimmer. in using the fin of the present invention, a swimmer will normally utilize his legs to develop a kick stroke, in developing a kick stroke, each foot of a swimmer is displaced from a position which is normally in the plane of the body into a position where the foot is located at a position below the plane of the body and the legs are pivoted above the hip socket to move the leg, foot and swim fin affixed to the foot through a predetermined angle. For purposes of this description, a "power stroke" refers to that portion of a swimmer's movement wherein the foot and fin is moved from a position which is substantially planar to the position of the swimmer's body to a position where the foot and fin are moved to a point located below the swimmer's body and further into the water. The term "reset stroke" refers to that portion of the kicking action wherein the foot of a swimmer is moved from the position located at a point below the plane of the swimmer's body and in the water to a position wherein the foot and associated fin is moved to a point which is in a plane substantially parallel to the plane of the swimmer's body.

The preferred embodiment, as shown in FIGURES 1 through 4 and 14 through 22 is comprised of a planar trapezoid shaped flexible base 24 with converging sides 26 and a centrally located inwardly converging contour 28 in a vee-shape forming tips 30 on either side. The base 24 is wider at the forward portion than the rearward portion, and the sides 26 are in an acute angular relationship. The tips 30 are turned upward 32, as illustrated in FIGURES 1, 2, 5, 6 and 7. The upward orientation is related to the normal usage, as attached to the swimmer's feet. The flexibility causes this shape to flatten somewhat when the fin is placed horizontal due to the effect of gravity. The drawings depict the fin without this outside influence, or as i t wou l d appear i n the water w ith no force aga inst i t .

The length of the tips 30 are at least 25 percent of the length of the overall base 24 and the tips are disposed at an acute angle inward relative to the base center, as shown in FIGURES 6 and 7. This allows each tip 30 to have a compound angular relationship, both upward and inward from the balance of the base 2M .

A pair of foot retainers 34 are formed integrally with the base 24 on the rearward narrowed portion, each having a rearward opening 36, the same approximate size a.= the swimmer's foot. A forward opening 38 is formed at the opposite end, permitting the user's toes to protrude therefrom. Each retainer 34, therefore, is in a hollow bridge shape and. are positioned side-by-side at a forwardly extending acute angle. This orientation placer the swimmer's feet with the toes pointed slightly inward providing a comfortable stance with the legs allowed to employ the muscles at the optimum position.

The entire fin, including the base 24, tips 30 and foot retainers 34 is formed as an integral one-piece molding of resilient material, such as a polyurethane plastic. while this material is preferred, any other type of substance may be used with equal ease and functional capability.

In the preferred embodiment, the force developed during the power stroke by a swimmer results in the feet receiving portion of the fin being urged tightly against each foot of a swimmer such that the swimming fin will remain on the swimmer's feet without the need of fastening means. However, in order to provide additional security so that a fin will not fall off when the user is not swimming or so that contact with other objects will not pull the fin off of the swimmer, a strap 40 with fastening means 42 connected to the fin may be utilized to maintain the swim fin in engagement with the swimmer's foot.

This strap 40, shown in FIGURES 1 through 12, is therefore employed. Each strap 40 is preferably made of a woven thermoplastic or cotton fiber and is attached, to the foot retainers 34 by fastening means 42, such as riveting, screws and nuts, etc., all well known in the art. Further, the strap 40 contains a stiffening sleeve 44 in the center to distribute the force evenly on the swimmer's heel. This sleeve is also made of a hollow thermoplastic material that is resilient, yet pliable enough to conform to the swimmer's heels. In order to make the strap 40 adjustable in length, a buckle 46 is employed, also well known in the art. This buckle 46 may be metal or Plastic with a high grade of rigid thermoplastic being preferred, such as polyurethane, polyamide, phenol i c polyester, reinforced polycarbonate, or the like. The tips 30 of the base 24 have a movable end, which is deflectable when the swimmer applies force in one direction or the other. This end of the tip 30 is formed with a cross-section, as shown in FIGURE 16, and varies in thickness from the sides tapered to a parallel center portion inbetween. The end of the tip 30 tapers similarly from the extreme forward point, allowing a predetermined flexibility and a streamlined shape for traversing through the water with a minimum of turbulence. The rearward portion of the base 30 is somewhat thicker, as illustrated in FIGURE 8, which provides sufficient structural integrity to maintain a grip on the swimmer's feet and provide a structural base to support the foot retainers 34.

The tips 30 and forward and middle portion of the base 24 are flexible and deflect when forced by the water, as the cross-section shown in FIGURES 14 through 16, is tapered on the outside edges. Further, the base 24 is parallel and. relatively flat in the middle, and, along with the tapered edges, permits a predetermined amount of flexibility which is optimum for the swimmer using the fins. The rearward portion of the base 24 is somewhat thicker than the parallel middle section, which provides sufficient strength to maintain a firm grip on the swimmer's feet.

The tips 30 of the base 24 are responsive to a hydraulic force urged against the upper surface of the fin permitting a flexure of the tips through an arcuate shaped path curling away from the forward opening 36 of the foot retainer 34 creating a build-up of water pressure within the lower surface, as it is responsive to a reaction force produced by the thicker cross-sect ion of the rearward portion when the hydraulic force being urged against is discontinued immediately deflecting the tips 30, causing a snapping action when the tips 30 abruptly reverse direction. The combination of flexing and snapping produce the desired propelling force as water is channeled through the inwardly diverging contour over and under the tapered edges of the flexible base 24. The snapping action is the novelty of the invention in combination with both feet of the swimmer being used together creating the combined propulsion force that allows the fin to easily propel the swimmer through the water. The snapping action of the tips 30 and middle portion of the base 24 is illustrated in a sequence in FIGURES 17 and 19.

Further, FIGURES 20 through 22 depict the fins in the reset stroke relative to the force of the water completing the action produced by the swimmer during the propulsion cycle of the fin. FIGURES 17 and 19 illustrate the position of the fin at the beginning, intermediate and bottom part of the power stroke, each viewed from the same position, The swimmer's feet are positioned within the retainers 34 such that the toes extend through the forward opening 38 as each swimmer's foot is moved in any direction toward the toes, the upper surface of the base 24 is urged against the water which generates a force in the direction shown by arrow 100. The force 100 deflects the tips 30 away from the forward opening 38 causing them to snap and deflect in a direction toward the base 24 at the rearward portion. AS illustrated in FIGURE 17, the feet of the swimmer are at a position midway during the power stroke and the force of the water illustrated by arrow 100 deflects the flexible fin such that the tips 30 are deflected along an arcuate path towards the rearward portion of the fin. The deflection of the fin base 24 combined with the snapping action of the upwardly extending movable tips 30 generate a propelling force which moves the swimmer through the water. FIGURE 18 illustrates that the deflected end of the upwardly extending movable tips 30 have undergone a snapping action to generate the propulsion force and that the same are deflected toward the integral rearward portion of the base 24.

FIGURE 19 illustrates the feet of a swimmer at the end of a power stroke. The force generated by the water, illustrated by arrow 100, is urged against the upper surface of the fin which urges the body 24 such that the tips are located at a distance which is spaced from and substantially parallel to the rearward portion of the base 24.

In conclusion, the propelling force is generated by the deflection of the tips 30 against the water force illustrated by arrow 100 and the snapping action of the tips 30 to propel the swimmer ahead.

FIGURE 20 through 22 illustrated the "reset stroke" with the feet of the swimmer located at the beginning, center and end of the reset stroke, respectively.

FIGURE 20 illustrates that as the feet of the swimmer are moved in a direction toward the heel that the force of the water represented by arrow 102 is urged against the lower surface of the base which urges the tips 30 toward the swimmer's toes and causes the tips 30 to be deflected toward each other which has the effect of reducing the total surface of the base 24 which is in contact with and reacts with the water.

FIGURE 21 illustrates that as the feet of the swimmer are moved into their intermediate position, the tips 30 are urged along an arcuate shaped path toward the swimmer's toes and the forward opening 38 by the force of the water illustrated by arrow 102.

FIGURE 22 illustrates the position of the feet of a swimmer at the end of the reset stroke wherein the force generated by the water illustrated by the arrow

102 has caused the tips 30 to be deflected' forward approximately 45 degrees forming an arcuate shaped cup member which retains a substantial volume of water and which generates a slightly negative pressure on the inner surface due to the fact that the water is moving across and spills across the lower surface of the base 24 along with the tips 30.

At the end of the reset stroke, the swimmer abruptly reverses the direction of foot movement which results in an abrupt reversal of the force generated by the water being reversed from the lower surface to the upper surface of the base 24. When the swimmer reverses the stroke, the tip 30 is deflected from a substantially forward position, as illustrated in

FIGURE 17 which causes a switching condition to occur abruptly. As the tips 30 are deflected from their forward position illustrated in FIGURE 20 to its rearward position illustrated in FIGURE 22, the tips 30 are moved in an arcuate shaped path which causes a

"snapping action". The combination of the deflection of the base 24 and the "snapping action" of the movable tips 30 produces the propelling motion as previously discussed.

The second, embodiment is illustrated in FIGURES 10 and. 11 and is identical to the preferred embodiment, except a number of ribs 48 are added integral with the underside of the base 24. These ribs 48 control the amount of flexibility of the fin, particularly in the forward portion and the tips 30. The ribs 48 may project from the bottom surface any convenient distance, however, it has been found that an extension of 0.38 inches (0.96 cm) is ideal for a normal sized fin.

The third embodiment is also basically the same as the preferred and is shown pictorially in FIGURE 9. The only difference is that the entire flexible base 24 is slightly turned upward base 50 relative to the user's feet starting just beyond the swimmer's toes where they contact the base 24 when they are not effected, by the stresses and. movement during use. The difference may appear to be slight, however, the functional characteristics change sufficiently to make a noteworthy difference.

The fourth embodiment is a combination of the second and third, having the ribs 48 and upwardly turned base 50, both previously described. This embodiment is illustrated in FIGURE 12 and, again, provides its own unique characteristics of functional operation.

While the invention has been described in complete detail and pictorially shown in the accompanying drawings, it is not to be limited to such details, since many changes and modification may be made in the invention without departing from the spirit and the scope thereof. Hence, it is described to cover any and all modifications and forms which may come within the language and scope of the appended claims.

Claims

CLA IMS

1. A single swim fin adapted to be interjoined by both feet of a swimmer comprising:

a) a planar trapezoid shaped flexible base having a forward portion, a rearward portion and a pair of converging sides, said forward portion further having a centrally located, vee-shaped inwardly converging contour defining a pair of tips distal from the rearward portion in a symmetrical orientation with the forward portion wider than the rearward portion and the sides having an equal acute angular relationship, b) a pair of foot retainers integral with the rearward portion of said base, each retainer having a rearward opening adaptable to receive a foot and a forward opening of a proportion allowing toes to protrude therethrough, each retainer defining a bridge formed in unity with the base and in concert with each other, c) said tips of the base each having a movable end which are deflectable, further, said tips having a cross-sectional shape varying in thickness from the sides in a tapered manner to a parallel portion inbetween. and in like manner from the extreme forward portion allowing flexibility in a predetermined manner with said rearward portion somewhat thicker than the parallel base between the sides providing sufficient structural integrity to maintain a grip on the wearer's feet, and,

d) said tips of the base being responsive to a force urged against an upper surface thereof to flex the tips through an arcuate shaped path curling away from the forward opening of the foot retainer creating a build-up of water pressure within a flexed lower surface, also being responsive to a reaction force produced by the thicker cross-section of the rearward portion when the force being urged against is discontinued immediately deflecting the tips causing a snapping action wherein the tips abruptly reverse direction with the combination of flexing and snapping producing a propelling force, as water is channeled through the inwardly diverging contour over and under the tapered edges of the flexible base.

2. The swim fin as recited in claim 1 wherein said foot retainers are disposed adjacent to each other at a forwardly extending acute angle positioning a user's feet such that one's toes are pointed slightly inward providing a comfortable relationship at the strongest muscular orientation.

3. The swim fin as recited in claim 1 wherein said tips are turned, upward on the forward portion relative to the user in the normal state without the effect of outside influence's.

4. The swim fin as recited in claim 1 wherein the flexible base is slightly turned upward relative to the user's feet starting just beyond a position where the user's toes are in contact with the base in a normal state uneffected by outside influences.

5. The swim fin as recited in claim 1 wherein the length of the tips of the base are at least 25 percent of the length of the overall base and the tips are disposed at an. acute angle inward relative to the base center for providing resistance on a power stroke thus limiting resistance when collapsing towards an upper surface of the fin on a reset stroke.

6. The swim fin as recited in claim 1 further- comprising an adjustable strap attached to each foot retainer at each side of the rearward opening in a looping manner extending around the user's heel holding both swimmer's feet securely within the retainers while in use and allowing the strap to be shortened or lengthened to accommodate the size of the swimmer's feet.

7. The swim fin as recited in claim 1 further comprising a plurality of ribs formed integrally with the flexible base on a side opposite the foot retainers controlling the amount of flexibility of the fin. particularly in the forward portion.

8. The swim fin as recited in claim 7 wherein said ribs extend from the base 0.38 inches (0.96 cm).

9. The swim fin as recited in claim 1 wherein the entire fin is formed as an integral one-piece molding of resilient material.

10. The swim fin as recited in claim 9 wherein said resilient material further comprises a polyurethane thermoplastic.