Retractable swim fins

Retractable swim fins that attach to the legs of a swimmer to aid movement through the water. In one example embodiment, a retractable swim fin includes an upper support frame, a lower support frame, and a sliding assembly connecting the upper support frame to the lower support frame. The upper support frame is configured to be attached to the front of a swimmer's lower leg. The lower support frame includes means for aquatic propulsion and is configured to extend, in a swimming position, to a position beneath the sole of the swimmer's foot. The lower support frame is also configured to retract, in a walking position, to a position above the sole of the swimmer's foot. The walking position enables the swimmer to walk barefoot on a surface without the lower support frame substantially contacting the surface. The sliding assembly is configured to allow the lower support frame to retract.

BACKGROUND

1. Field of Invention

The present invention generally relates to swim fins and, in particular, to retractable swim fins that attach to the legs of a swimmer to aid movement through the water.

2. Description of Related Art

Typical swim fins are worn on the foot of a swimmer to aid movement through the water while surface swimming or participating in swimming-related activities such as bodyboarding, bodysurfing, kneeboarding, riverboarding, snorkeling, and various types of underwater diving. For example, scuba divers use swim fins to move through water efficiently, as human feet provide relatively poor thrust, especially when the diver is carrying equipment that increases hydrodynamic drag.

Unfortunately, typical swim fins have several problems. For example, since typical swim fins attach only to the foot and heel of a swimmer, typical swim fins can cause severe ankle strain and calf muscle fatigue. This is due to the mass of water moved by the fin and the fact that the ankle joint rotates through a complex, non-planar, arc. Further, the ankle does not generally orient the foot optimally for forward thrust, thus reducing the efficiency of the hydrofoil properties of the fin. Further, typical swim fins increase the footprint of the swimmer and are constructed of heavy and bulky materials, thus making it difficult to walk, as is often necessary when entering or exiting water via a shoreline, a boat, or a dock.

Another major problem with typical swim fins is related to an integral foot pocket which at least partially encloses the foot of the swimmer. Unfortunately, foot pockets tend to inadvertently gather foreign objects such as sand or gravel which can chafe the foot of the swimmer making swimming and walking uncomfortable or even painful, and can further risk infection. Also, foot pockets tend to retain some water which can be uncomfortable because the foot of the swimmer does not dry even when the swimmer is out of the water. Further, it can be difficult or impossible to clear foreign objects or water from the foot pocket without completely removing the swim fin from the foot of the swimmer. Also, foot pockets tend to restrict the other types of footwear, such as sandals or water socks, that can simultaneously be worn. Finally, foot pockets deprive the swimmer of the joyful sensation of walking bare-footed across the warm sand of a sandy beach or the cool grass of a grassy lawn.

BRIEF SUMMARY OF INVENTION

A need therefore exists for a swim fin that eliminates the above-described disadvantages and problems.

In one example embodiment, a retractable swim fin includes an upper support frame, a lower support frame, and a sliding assembly connecting the upper support frame to the lower support frame. The upper support frame is configured to be generally positioned along and attached to the front of a swimmer's lower leg between the swimmer's knee and ankle. The lower support frame includes means for aquatic propulsion and is configured to extend, in a swimming position, to a position beneath the sole of the swimmer's foot. The lower support frame is also configured to retract, in a walking position, to a position above the sole of the swimmer's foot. The walking position enables the swimmer to walk barefoot on a surface without the lower support frame substantially contacting the surface. The sliding assembly is configured to allow the lower support frame to retract by sliding upward from the swimming position to the walking position.

In another example embodiment, a retractable swim fin includes an upper support frame, a lower support frame, and a sliding assembly connecting the upper support frame to the lower support frame. The upper support frame is configured to be generally positioned along and attached to the front of a swimmer's lower leg between the swimmer's knee and ankle. The lower support frame includes a lower blade and is configured to extend, in a swimming position, to a position beneath the sole of the swimmer's foot. The lower support frame is also configured to retract, in a walking position, to a position above the sole of the swimmer's foot. The walking position enables the swimmer to walk barefoot on a surface without the lower support frame substantially contacting the surface. The sliding assembly is configured to allow the lower support frame to retract by sliding upward from the swimming position to the walking position.

In yet another example embodiment, a retractable swim fin includes an upper support frame, a lower support frame, and a sliding assembly connecting the upper support frame to the lower support frame. The upper support frame is configured to be generally positioned along and attached to the front of a swimmer's lower leg between the swimmer's knee and ankle. The lower support frame includes a plurality of louvers and is configured to extend, in a swimming position, to a position beneath the sole of the swimmer's foot. The lower support frame is also configured to retract, in a walking position, to a position above the sole of the swimmer's foot. The walking position enables the swimmer to walk barefoot on a surface without the lower support frame substantially contacting the surface. The sliding assembly is configured to allow the lower support frame to retract by sliding upward from the swimming position to the walking position.

These and other aspects, features and advantages of the invention will become more fully apparent from the following detailed description of preferred embodiments and appended claims.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

It will be readily understood that the components of the present invention, as generally described and illustrated in the Figures herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of preferred embodiments is not intended to limit the scope of the invention, as claimed, but it is merely representative of some of the presently preferred embodiments of the present invention.

The present invention is generally directed towards retractable swim fins that are worn on the foot of a swimmer to aid movement through the water while surface swimming or participating in swimming-related activities such as bodyboarding, bodysurfing, kneeboarding, riverboarding, snorkeling, and various types of underwater diving. The swim fins disclosed herein are also specifically designed to be worn by the swimmer while the swimmer is walking in shallow water or out of the water such as on a beach, a boat, or a dock, for example, without interfering with the stride of the swimmer.

Additionally, to assist in the description of the swim fins, words such as top, bottom, front, rear, right, left, up, and down are used to describe the accompanying Figures, which are not necessarily drawn to scale. It will be appreciated, however, that the present invention can be located in a variety of desired positions, including various angles, sideways and even upside down. A detailed description of the swim fins now follows.

As discussed below and shown in the accompanying Figures, the swim fins may be worn by a swimmer in a “swimming position” while swimming as well in a “walking position” while walking along in or out of the water. This dual-functionality avoids the time and hassle of having to remove the swim fins in order to transition from swimming to walking. The dual-functionality also enables the swimmer to comfortably wear the swim fins well in advance of entering the water to swim, even when the swimmer must walk short or long distances before entering the water to swim. Further, the swim fins allow the swimmer to comfortably wear the swim fins even while wearing other footwear, such as sandals or water socks, for example. It is understood, however, that in some applications the swim fins can also be used without activating the retractable feature of the swim fins.

First Example Swim Fin

As disclosed inFIGS. 1-5, a first example swim fin100generally includes an upper support frame102, a lower support frame104, and a sliding assembly106connecting the upper support frame102to the lower support frame104. The sliding assembly106is configured to allow the lower support frame104to retract by sliding upward from a “swimming position,” disclosed inFIGS. 1 and 5, to a “walking position,” disclosed inFIGS. 2 and 4, while the upper support frame102remains securely attached to the lower leg202of a swimmer200.

As disclosed inFIGS. 1 and 5, in the swimming position, the lower support frame104is configured to extend to a position beneath the sole of the swimmer's foot204. The swimming position disclosed inFIGS. 1 and 5enables the swimmer200to swim through water with increased thrust as compared to swimming with a bare foot. As disclosed inFIGS. 2 and 4, in the walking position, the lower support frame104is configured to retract to a position above the sole of the swimmer's foot204. The walking position disclosed inFIGS. 2 and 4enables the swimmer200to walk barefoot on a surface300disclosed inFIG. 4without the lower support frame104substantially contacting the surface300and without the swim fin100interfering with the stride of the swimmer200.

As disclosed inFIGS. 4 and 5, the upper support frame102is configured to be generally positioned along the front of lower leg202of the swimmer200between the knee206and the ankle208. The upper support frame102generally includes two braces108and110and two cross members112and114. The braces108and110are configured to be positioned on either side of the swimmer's lower leg202. The braces108and110are also configured to be attached to the sliding assembly106. The cross members112and114connect and support the braces108and110. The cross members112and114may further be configured to at least partially wrap around the front of the swimmer's lower leg202.

The upper support frame102is configured to be securely attached to the swimmer's lower leg202, instead of to the foot204or ankle208. For example, the upper support frame102may further include a pair of straps116and118configured to attach the upper support frame102to the front of the swimmer's lower leg202. The straps116and118may be adjustable straps to accommodate multiple swimmers with variously sized lower legs. For example, each of the straps116and118may include a buckle, Velcro®, a ratchet buckle, or other adjustable fastener to accommodate various sizes of lower legs. The straps116and118may be formed from various materials or combinations of materials including, but not limited to, polychloroprene.

The upper support frame102can be constructed, by molding for example, from a relatively rigid substance, such as a relatively rigid plastic, in order to provide structural support to the sliding assembly106. It is understood, however, that portions of the upper support frame102, such as middle portions of the two cross members112and114, may be constructed from a less rigid substance in order to allow the upper support frame102to fit snuggly against the swimmer's lower leg202during swimming and walking.

As disclosed inFIGS. 4 and 5, the swim fin100may further include padding120positioned between portions of the upper support frame102and the front of the swimmer's lower leg202and foot204. The padding120is configured to make direct contact with the swimmer's lower leg202and cushion the force of the braces108and110and the cross members112and114of the upper support frame102against the swimmer's lower leg202and foot204as the straps116and118are tightened and as the swimmer200walks and swims wearing the swim fin100. The padding120can be formed, by stamping for example, from a soft and comfortable material, such as polychloroprene.

As disclosed inFIGS. 1-3, the lower support frame104generally includes two braces122and124, two cross members126and128, and a lower blade130. The lower support frame104may also include a blade protector132to protect the distal end of the lower blade130from damage. The braces122and124are configured to be positioned on either side of the swimmer's foot204. The braces122and124are also configured to be attached to the sliding assembly106. The cross members126and128connect and support the braces122and124. The cross members126and128may further be configured to provide support to a portion of the lower blade130. Advantageously, the cross member126and128and the lower blade130may enable the dorsum of the swimmer's foot204to contribute force to the downstroke of the swim fin100without any portion of the swim fin100being attached to the swimmer's foot204.

The lower support frame104can be constructed, by molding for example, from a relatively rigid substance, such as a relatively rigid plastic, in order to provide structural support to the lower blade130and the sliding assembly106. It is understood, however, that portions of the lower support frame104, such as lower portions of the braces122and124, may be constructed in such a way as to allow these portions to flex up (during a downstroke) and down (during an upstroke) while swimming. For example, the cross section of braces122and124could be generally rectangular, and the upper and lower sides of the braces122and124can be grooved to facilitate flexion in the upward and downward directions. Alternatively, or additionally, portions of the braces122and124can be constructed from a less rigid substance in order to allow these portions to flex up and down during swimming. In at least some example embodiments, the flexible portions of the braces122and124enable the lower support frame104to flex up and down, but avoid enabling the braces122and124to flex inward or side to side. For example, the cross members126and128can support the braces122and124in order to avoid the braces122and124from flexing inward toward one another or outward away from one another. Further, the function of the cross members126and128can be augmented by one or more additional cross members, or the cross member128can be removed as disclosed below in connection withFIGS. 8 and 9.

The lower blade130can be formed from a relatively light and flexible material, such as a relatively flexible vinyl, silicon, rubber, or rubberized rip-stop nylon material, in order to allow the lower blade130to flex during swimming. Furthermore, the lower blade130may be made from a partially or totally transparent material in order to avoid impeding the view of the swimmer's foot204during walking Further, the lower blade130may incorporate one or more hydrofoil chutes, such as the hydrofoil chute133, that allow water to be pushed through the lower blade130in a direction that is generally inline with the forward motion of the swimmer200. These hydrofoil chutes may be formed from a material that allows the chutes to transition from protruding from the top surface of the lower blade130(during a downstroke) to protruding from the bottom surface of the lower blade130(during an upstroke) in order to direct water propulsion and provide increased forward thrust during both the up and downstrokes while swimming.

As disclosed inFIG. 3, the sliding assembly106includes two substantially parallel rails134and136attached to the upper support frame102, two slider clamps (not shown) attached to the brace122of the lower support frame104, and two slider clamps138attached to the brace124of the lower support frame104. As disclosed inFIGS. 1,2,4, and5, each slider clamp138at least partially surrounds one of the rails134or136and is configured to allow the lower support frame104to retract by sliding upward along the rails134and136from the swimming position to the walking position and to extend by sliding downward along the rails134and136from the walking position to the swimming position.

It is noted that in this embodiment, the slider clamps138may either be formed as cylindrical slider clamps that each completely surrounds one of the rails134or136, or the slider clamps138may be formed as C-shaped slider clamps that each only partially surrounds one of the rails134or136. Where the slider clamps138are formed as C-shaped slider clamps, the slider clamps138of the lower support frame104may be clipped onto the rails134and136without detaching either end of each rail from the upper support frame102. C-shaped slider clamps thus enable the lower support frame104to be quickly and easily swapped out with another lower support frame, such as any of the lower support frames disclosed inFIG. 8,9, or11, without the use of tools. It is further noted that instead of two slider clamps138, each of the braces122and124of the lower support frame104may include only one slider clamp138or three or more slider clamps138. Further, each slider clamp138may be formed to at least partially surround a greater or lesser length of the corresponding rail134or136.

As disclosed inFIG. 3, the sliding assembly106may also include a pair of support arms140, a pair of fasteners142, a pair of lower stops144and corresponding hooks146, a pair of elastic bands148, a pair of hooks150attached to the lower support frame104, and a pair of spring-loaded posts152. The fasteners142are configured to attach the rails134and136to the support arms140, respectively. The support arms140function to attach the rails134and136, respectively, to the upper support frame102. The support arms140also function to limit the upward travel of the lower support frame104. The lower stops138function to limit the downward travel of the lower support frame104.

As disclosed inFIGS. 3 and 5, the elastic bands148attach between the hooks146and150. It is noted that the hooks146and150disclosed in the Figures could be replaced with hooks configured as slightly opened eyelets in order to more securely retain the elastic bands148. The elastic bands148are configured to automatically slide the lower support frame104from the walking position to the swimming position. The elastic bands148, in combination with a pair of friction bumps154(only one of which is shown inFIG. 5) or other higher-friction surfaces or structures on the rails134and136, are also configured to maintain the lower support frame104in the swimming position. Although not shown in the Figures, the rails134and136may be curved toward the bottom to encourage the lower support frame104to remain in the swimming position or to fine tune the functional orientation of the lower support frame104once extended into the swimming position.

The elastic bands148, in combination with a pair of friction bumps154(only one of which is shown inFIG. 5) or other higher-friction surfaces or structures on the rails134and136, allow the lower support frame104to automatically slide upward if the swimmer200stands on the swim fin100in the swimming position without bending or otherwise damaging the lower support frame104and/or the sliding assembly106of the swim fin100. The bias of the elastic bands148, in combination with a pair of friction bumps154(only one of which is shown inFIG. 5), can also and more typically be overcome by the swimmer grasping the lower support frame104in the swimming position and manually pulling upward, thus sliding the lower support frame104to the walking position

As disclosed inFIGS. 3 and 4, when the lower support frame104is manually slid into the walking position, the elastic bands148are stretched. Once the lower support frame104is fully retracted into the walking position, the spring-loaded posts152function to lock the lower support frame104in the walking position. The four slider clamps138(only two of which are shown in the Figures) may be configured with inner ramped surfaces so that the lower support frame104can manually slid into the walking position without manipulating the spring-loaded posts152. However, in order to allow the elastic bands148to automatically extend lower support frame104into the swimming position, the spring-loaded posts152must be manually pressed into the rails134and136to allow the two lower slider clamps138(only one of which is shown in the Figures) to slide down past the spring-loaded posts152. The two upper slider clamps138(only one of which is shown in the Figures) may be configured with two-way ramped surfaces to automatically slide up or down past the spring-loaded posts152without requiring manual manipulation of the spring-loaded posts152.

The spring-loaded posts152are therefore one example structural implementation of a means for locking the lower support frame104in the walking position. It is noted that a variety of means may be employed to perform the functions disclosed herein concerning the spring-loaded posts152locking the lower support frame104in the walking position. Thus, the spring-loaded posts152comprises but one example structural implementation of a means for locking the lower support frame104in the walking position.

Accordingly, it should be understood that this structural implementation is disclosed herein solely by way of example and should not be construed as limiting the scope of the present invention in any way. Rather, any other structure or combination of structures effective in implementing the functionality disclosed herein may likewise be employed. For example, in some example embodiments of the example swim fin100, the spring-loaded posts152may be replaced or augmented with one or more other locking mechanisms, latches, fasteners, or hooks. For example, a single latch may be employed to lock the lower support frame104to the upper support frame102with the lower support frame104in the walking position. In yet other example embodiments, the locking functionality may be accomplished by some combination of the above example embodiments. Also, although not shown in the Figures, the rails134and136may be curved toward the top to encourage the lower support frame104to remain in the walking position or to fine tune the functional orientation of the lower support frame104once retracted into the walking position to reduce the possibility of one lower support frame104from striking the other. A curve formed toward the top of the rails134and136may thus be another structural implementation of a means for locking the lower support frame104in the walking position.

The lower blade130, including the hydrofoil chute133, functions to propel the swimmer200through the water during downstrokes and upstrokes of the swimmer's lower leg202. The lower blade130is therefore one example structural implementation of a means for aquatic propulsion. It is noted that a variety of means may be employed to perform the functions disclosed herein concerning the lower blade130propelling the swimmer through the water. Thus, the lower blade130comprises but one example structural implementation of a means for aquatic propulsion.

Accordingly, it should be understood that this structural implementation is disclosed herein solely by way of example and should not be construed as limiting the scope of the present invention in any way. Rather, any other structure or combination of structures effective in implementing the functionality disclosed herein may likewise be employed. For example, in some example embodiments of the example swim fin100, the lower blade130may be replaced or augmented with one or more other blades, hydrofoil chutes, or louvers, such as any of the louver disclosed inFIGS. 8-11. In yet other example embodiments, the aquatic propulsion functionality may be accomplished by some combination of the above example embodiments.

First Alternative Swim Fin

With reference now toFIG. 6, aspects of a first alternative swim fin100′ are disclosed. The first alternative swim fin100′ is identical to the first example swim fin100disclosed inFIGS. 1-5, except that the first alternative swim fin100′ includes a first alternative sliding assembly106′ that includes an upper blade156positioned between the two alternative rails134′ and136′. It is noted that the four alternative slider clamps138′ (only two of which are disclosed inFIG. 6) are configured as C-shaped slider clamps with the open portion of the C shape aligning with the position of the upper blade156so that the upper blade156does not impede the sliding of the slider clamp138′ up and down along the rails134′ and136′.

The upper blade156can be formed from any of the material mentioned above in connection with the lower blade130. Furthermore, the upper blade156may be made from a partially or totally transparent material in order to avoid impeding the view of the swimmer's foot204or lower leg202during walking Further, the upper blade156may incorporate one or more hydrofoil chutes, such as the hydrofoil chute158, that allow water to be pushed through the upper blade156in a direction that is generally inline with the forward motion of the swimmer200. These hydrofoil chutes may be formed similarly and function similarly to the hydrofoil chutes, such as the hydrofoil chute133, discussed above in connection with the lower blade130.

The upper blade156, including the hydrofoil chute158, functions to propel the swimmer200through the water during downstrokes and upstrokes of the swimmer's lower leg202, in tandem with the lower blade130. The upper blade156is therefore one example structural implementation of a means for aquatic propulsion. It is noted that a variety of means may be employed to perform the functions disclosed herein concerning the upper blade156propelling the swimmer through the water. Thus, the upper blade156comprises but one example structural implementation of a means for aquatic propulsion.

Accordingly, it should be understood that this structural implementation is disclosed herein solely by way of example and should not be construed as limiting the scope of the present invention in any way. Rather, any other structure or combination of structures effective in implementing the functionality disclosed herein may likewise be employed. For example, in some example embodiments of the example swim fin100′, the upper blade156may be replaced or augmented with one or more other blades, hydrofoil chutes, or louvers, such as any of the louvers disclosed inFIGS. 8-11. In yet other example embodiments, the aquatic propulsion functionality may be accomplished by some combination of the above example embodiments.

It is further noted that the first alternative swim fin100′ could be employed by the swimmer200with the lower support frame104completely removed, leaving only the upper blade156, or other means for aquatic propulsion positioned between the two alternative rails134′ and136′, to propel the swimmer200through the water.

Second Alternative Swim Fin

With reference now toFIG. 7, aspects of a second alternative swim fin100″ are disclosed. The second alternative swim fin100″ is identical to the first example swim fin100disclosed inFIGS. 1-5, except that the second alternative swim fin100″ includes a second alternative sliding assembly106″ in which the rails134and136gradually taper toward each other traveling upward from the bottom of the upper support frame102to the top of the upper support frame102. This tapering of the non-parallel rails134and136requires a lower support frame having flexible cross members and a flexible means for aquatic propulsion (not shown) to enable the braces of the lower support frame (not shown) to collapse toward each other as the lower support frame travels upward along the non-parallel rails134and136.

The second alternative sliding assembly106″ of the second alternative swim fin100″ can function to decrease the width of a corresponding lower support frame (not shown) when the lower support frame is slid into the walking position, thus reducing the possibility of the two lower support frames from contacting one another when the swimmer200is walking wearing a pair of the second alternative swim fins100″.

First Alternative Lower Support Frame

With reference now toFIG. 8, aspects of a first alternative lower support frame104′ are disclosed. The first alternative lower support frame104′ is identical to the lower support frame104disclosed inFIGS. 1-5, except that the first alternative lower support frame104′ is missing the cross member128, the blade130is replaced with louvers160-168, and the blade protector130is replaced with a louver protector170. Each of the louvers160-168may optionally include a pair of pins172connecting each louver to the braces122and124. Further, each of the louvers160-168is connected to the braces122and124with a wedge-shaped elastic webbing173on each side of each louver.

During swimming, each of the louvers160-168automatically rotates downward during an upstroke (as shown for the louver168in phantom lines168′) and automatically rotating upward during a downstroke in order to direct water propulsion and provide increased forward thrust during both the up and downstrokes while swimming. The elastic webbings173tend to constrain the upward and downward rotations of the louvers160-166within a functional arc (as shown for the stretched elastic webbings173in phantom lines173′).

Second Alternative Lower Support Frame

With reference now toFIG. 9, aspects of a second alternative lower support frame104″ are disclosed. The second alternative lower support frame104″ is identical to the first alternative lower support frame104′ disclosed inFIG. 8, except that the louvers160-168are replaced with louvers175-182, the louver protector170is replaced by a louver protector184, and the elastic webbings173are replaced with elastic tabs174.

During swimming, each of the louvers175-182functions similarly to the lovers160-168disclosed inFIG. 8, with each of the louvers175-182automatically rotating downward during an upstroke (as shown for the louver182in phantom lines182′) and automatically rotating upward during a downstroke in order to direct water propulsion and provide increased forward thrust during both the up and downstrokes while swimming. The elastic tabs174allow the automatic downward and upward rotation of the louvers175-182, but do tend to constrain the downward and upward rotations of the louvers175-182within a functional arc (as shown for the stretched elastic tabs174in phantom lines174′).

It is understood that the elastic tabs174can be positioned near the edges of the louvers175-182, as disclosed inFIG. 9, or the elastic tabs174can alternatively be positioned more toward the middle of the louvers175-182. It is further understood that the elastic tabs174can attach each of the louvers175-182to the braces122and124instead of to the surrounding louvers. For example, the louver182can include two tabs (not shown) that attach the louver182to the braces122and124.

Further, as disclosed inFIGS. 9 and 10, each of the louvers175-182includes a pair of relatively rigid plates186that is overmolded with a relatively flexible overmolding188. For example, the plates186may be formed of metal or plastic and the overmolding188may be formed from rubber. The cross member126may also be similarly configured so that both the cross member126and the louvers175-182are able to flex down the middle to enable the braces122and124of the second alternative lower support frame104″ to collapse toward each. This semi-collapsible configuration of the second alternative lower support frame104″ enables the second alternative lower support frame104″ to be employed in the second alternative swim fin100″ with the non-parallel rails134and136disclosed inFIG. 7.

It is noted that the semi-collapsible configuration of the second alternative lower support frame104″ can alternatively be accomplished with relatively rigid plates that are fastened to, instead of being overmolded to, a relatively flexible middle section (not shown).

Third Alternative Lower Support Frame

With reference now toFIG. 11, aspects of a third alternative lower support frame104′″ are disclosed. The third alternative lower support frame104′″ is identical to the first alternative lower support frame104′ disclosed inFIG. 8, except that the louvers160-168are replaced with louvers186-194which do not include the pins172nor the elastic tabs174. Instead, each of the louvers186-194is formed from a semi-rigid material, such as rubber or a rubber-like material, and each is attached to the braces122and124along about one-third of the width of the louver. This relatively flexible construction and relatively sturdy attachment of each of the louvers186-194enables the louvers to function similarly to the louvers160-168without the functionality of the pins172or the elastic tabs174, with each of the louvers186-194automatically rotating downward during an upstroke (as shown for the louver194in phantom lines194′) and automatically rotating upward during a downstroke in order to direct water propulsion and provide increased forward thrust during both the up and downstrokes while swimming.

Other Alternative Embodiments

It is understood that the numbers, sizes, positions, and shapes of the hydrofoil chutes133and158disclosed inFIGS. 1 and 6, respectively, are example numbers, sizes, positions, and shapes only. Other numbers, sizes, positions, and shapes of hydrofoil chutes are possible and contemplated. For example, each of the blades130and156can have zero or more hydrofoil chutes. Further, the size of the hydrofoil chutes on the blades130and156can be smaller or larger than the chutes133and158disclosed inFIGS. 1 and 6, respectively. Also, the positions of the hydrofoil chutes can vary from the positions disclosed inFIGS. 1 and 6. Finally, the shapes of the openings of the hydrofoil chutes can differ from the generally parabolic shape disclosed inFIGS. 1 and 6. For example, the shapes of the hydrofoil chutes can be triagonal, trapezoidal, square, or pentagonal, for example. The openings of the hydrofoil chutes can also have any of a variety of different shapes.

It is further understood that although the braces122and124are disclosed throughout the Figures as having a generally flat configuration, it is understood that the distal ends of the braces122and124can instead be bent forward or backward in order to change the configuration of the walking position and/or swimming position of the braces122and124. It is understood the bending the braces122and124either forward or backward can affect the rotation of the swimmer's ankle208during swimming.

It is also understood that other aspects of the swim fins disclosed herein can be modified and/or combined. For example, the bias of the elastic bands148can be reversed in order to automatically slide the various lower support frames disclosed herein from the swimming position to the walking position. In this example, a means for locking can be employed to allow the lower support frame to lock in the swimming position. The lower support frame can also be configured to lock in one of multiple swimming positions and/or one of multiple walking positions.

It is also understood that although a pair of rails are disclosed in connection with each of the sliding assemblies106,106′, and106″, the functionality of the pair of rails could instead be combined into a single rail, or could be distributed across three or more rails. Further, the rails disclosed herein could be curved instead of straight. For example, the rails could be curved toward the top or bottom to encourage the lower support frame to remain in the walking position or swimming position, respectively. The curved rails can also fine tune the position of the lower support frame, such as the functional orientation of the lower support frame once extended into the swimming position or the functional orientation of the lower support frame once retracted into the walking position to reduce the possibility of one lower support frame from striking the other. In the walking position, the inside rail could also extend outward further than the outside rail to cause the lower support frame to rotate outward, thus reducing the possibility of the lower support frames from striking one another during walking. It is further understood that the functionality of the pair of elastic bands148can be combined into a single elastic band or similar means for biasing such as a corrosion-protected spring.

It is further understood that any of the lower support frames disclosed herein can additionally have a hinge or secondary slider to allow for a further extension of the associated means for aquatic propulsion.

It is also understood that any of the louvers disclosed inFIGS. 9-11may be loosely attached to the braces122and124using a wedge-shaped elastic webbing on each side of each louver, similar to the elastic webbings173ofFIG. 8. The elastic webbing can tend to constrain the degree of the upward and downward rotations of each of the louvers. This functionality can be augment, or replace, the functionality of the elastic tabs174disclosed inFIG. 9or the functionality of the about one-third width attached portions of the louvers disclosed inFIG. 11.

CONCLUSION

The example swim fins disclosed herein thus allow the lower support frame to be quickly and easily placed in the swimming position to allow a swimmer to swim and in the walking position to allow the swimmer to walk. By attaching only to the lower leg of the swimmer, instead of to the foot and heel, the swim fins disclosed herein cause less ankle strain and calf muscle fatigue than typical swim fins. Further, attaching to the leg instead of to the foot and heel of the swimmer allows the swim fins disclosed herein to avoid the problems associated with rotational movement of the ankle joint and to consistently propel the swimmer in a direction that is aligned with the direction of the swimmer's legs and torso. In addition, once slid into the walking position, the swim fins disclosed herein can remain attached to the swimmer's leg without increasing the footprint of the swimmer, thus making the swim fins ideal for walking when entering or exiting water via a shoreline, a boat, or a dock. The swim fins disclosed herein also have relatively efficient hydrofoil properties. These advantages of the swim fins disclosed herein are accomplished without the integral foot pocket included in typical swim fins, and thus the problems associated with foot pockets listed herein are completely avoided. Further, unlike users of typical swim fins, a swimmer can wear the swim fins disclosed herein in the walking position and simultaneously experience the joyful and uninhibited sensation of walking bare-footed across the warm sand of a sandy beach or the cool grass of a grassy lawn. A swimmer can also wear the swim fins disclosed herein while simultaneously wearing various other types of footwear, such as sandals or water socks.

Although this invention has been described in terms of certain preferred embodiments, other embodiments apparent to those of ordinary skill in the art are also within the scope of this invention. Accordingly, the scope of the invention is intended to be defined only by the claims which follow.