Collapsible swimming fins system for unidirectional thrust

Abstract

The system is configured as a modified swimming shoe with integrated support for collapsible fins positioned above the arch for short fins or above the arch and at the back of the swimming shoe to accommodate bigger fins. The system allows for maximum thrust during the power stroke while the resistance during the return stroke is no different from that of a barefoot swimmer due to the fins' passively switching to the collapsed position that closely mimics the dimensions of the foot. The resulting net efficiency of the propulsion thrust is much greater, and the complete movement (power stroke and return stroke) requires less energy and oxygen consumption. Collapsible fins offer greatly enhanced maneuverability by allowing abruptly changing direction and speed. The collapsible wrist fins further increase the efficiency of swimming while allowing the hand to remain free for other tasks.

Claims

1. A swimming fin system, comprised of a swimming shoe, and a support frame for the attachment of an assembly of fins/stops above the arch of the foot. The system allows for a manner of swimming that is more suitable for human anatomy, and therefore more efficient. As opposed to movements imitating the undulating fish mode of swimming, collapsible fins also allow for direct backward thrust.

2. The angle of attack, geometry, curvature, and size of the fins may vary depending on the degree of proficiency, comfort, and purpose. Larger fins can be accommodated by suitable modifications of the overall design including (but not limited to) thicker soles, higher positioning of the support frame, additional prongs in the support frame, and additional fin stops or hinges for limiting the range of fins' motion.

3. The support frame can be either integrated with the swimming shoe or made attachable with straps as a separate unit. The design of the support frame may vary depending on aesthetic considerations. It may have, for example, 2, 3 or more prongs, or a solid/perforated surface design, and it can be manufactured from a range of suitable materials including (but not limited to) plastics, resins, or carbon fiber.

4. The required range of motion of fins (from open to closed position) can be achieved using a variety of means including but not limited to external (in relation to fins) stops, 90O or 180O stop-hinges, and internal (in relation to fins) stops. The fins' moving parts, including hinges and armature, can also be integrated within the fin. The fins may also be equipped with straps that lock fins in the collapsed position to allow easy walking on the ground.

5. In yet another embodiment, fins attached to the feet are complemented by similarly constructed wrist fins to further improve the efficiency of swimming, speed, and maneuverability.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0013] FIG. 1 shows from different angles one of the possible designs for a swimming shoe with short collapsible fins and an external flat stop. 1swimming shoe; 2fin; 3external flat stop; 4closed position, minimum resistance during the return movement; 4open position, maximum thrust during the power stroke; 5fins with a flexible connector; 6the support structure integrated with the sole of the swimming shoe.

[0014] FIG. 2. shows from different angles one of the possible designs for a swimming shoe with large collapsible fins extending beyond the heel. A swimming shoe with larger fins and external flat stops. 1larger fins extending beyond the heel; 2closed position, minimum resistance during the return movement; 3open position, maximum thrust during the power stroke; 4modification of the support structure with an additional prong at the back of the swimming shoe; 5an additional external flat stop to limit the motion of the back portion of the extended fin.

[0015] FIG. 3 shows schematics of a range of possible designs for stopping a rotating portion of the fins. Various embodiments of contraptions for limiting the range of fins' motion. 1external flat stop; 2external stop using corners; 3stop attached to the support structure underneath the fins; 4strings or membranes attached to the support structure underneath the fins; 5180O hinge attached to both fins; 690O hinges limiting motion of individual fins.

[0016] FIG. 4 shows an overall design for wrist fins. The illustration of one of the embodiments of the wrist fins with external stop. 1hand; 2wrist glove living fingers uncovered; 3fins; 4external flat stop for fins connected with flexible material.

DETAILED DESCRIPTION OF THE INVENTION

[0017] The following review and figures are considered illustrative of the principles of the invention. The invention itself is not limited to the specific materials, variants of components, combinations thereof, and prototypes chosen for demonstration because there are many possible permutations of the design based on the same principle.

[0018] The invention addresses and resolves major drawbacks of traditional fins. It enhances thrust efficiency, maneuverability, and ease of transition from land to water and vice versa. As per this invention, the ratio of thrust generated during the power stroke and the return movement of the foot decidedly shifts in favor of the power stroke. Since return movement causes the passive collapse of the fins to the closed configuration, the resistance generated by a return movement is not different from the resistance of the foot without the fin. Similarly, minimum resistance during the return movement allows for an abrupt change of direction if necessary. Walking on land is facilitated by the fact that, while the fins are in a collapsed configuration, the edge of the fins is positioned above the sole of the swimming shoe and designed to be not in the way during walking or running.

[0019] The system is integrated with the sole of the swimming shoe (FIG. 1:4) although, in other possible embodiments, it may be constructed as a separate unit attachable to any swimming shoe using straps. The support frame is composed of the sole portion and several prongs (2-4) bent or curved so that they do not go beyond the dimensions of the footprint. The prongs on both sides merge above the arch of the foot at 1 inch or more and form a bridge for the attachment of the fins and stop devices (FIG. 1:4).

[0020] The fins can have various shapes and sizes and be flat or curved to better accommodate the shape and dimensions of the foot in closed position (FIG. 1:2,5,6,7). The primary limitation of fins' size and shape is to not impede the movement of the foot and to remain above the ground when standing and moving on a solid surface. The width of the fins, however, can be extended using increasing the thickness of the sole and/or the height of the support frame. In the variant of the design depicted in the figures (FIG. 1-3), the left and the right fins are connected by a flexible synthetic membrane (FIG. 1:7) at around 0.5 inches or more. The highly flexible synthetic membrane is affixed to the bridge formed by the support frame along the center line between the fins.

[0021] In the variant of the design depicted in the figures (FIGS. 1-3), the optimal rotation angle of the fins is enforced by placing an external stop above the fins (FIG. 1:3, shape and size may vary), so that fins provide the widest area during the power stroke in an open position (FIG. 1:6; FIG. 2:5). In other variants of the system the rotation of fins may be regulated by other types of external/internal stops or hinges (FIG. 3). During the return stroke, the fins passively assume a closed position (FIG. 1:5; FIG. 2:4) thus reducing the area causing resistance to the dimensions of the swimming shoe, i.e., smallest possible.

[0022] When necessary, the system can accommodate longer fins. The attachment of longer fins (FIG. 2:1) requires a modified support frame with a complimentary prong, a bridge for the extended portion of the fins (FIG. 2:6), and the addition of a secondary stop behind the heel of the swimming shoe (FIG. 2:2).

[0023] Utilizing similar principles, the present fin system for feet is complemented by the swimming fin system for wrists (FIG. 4:1). The wrist fins (FIG. 4:4) are curved to follow the curvature of the wrist (FIG. 4:2) and are mounted on the wrist glove (FIG. 4:3) that leaves fingers uncovered to allow underwater activities requiring fine motor skills. In the variant of the design depicted in FIG. 4 the maximum rotation of the fins is limited by the external stop (FIG. 4:5).