Classifications

• • A—HUMAN NECESSITIES
  • A63—SPORTS; GAMES; AMUSEMENTS
  • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
  • A63B31/00—Swimming aids
  • A63B31/08—Swim fins, flippers or other swimming aids held by, or attachable to, the hands, arms, feet or legs
  • A63B31/10—Swim fins, flippers or other swimming aids held by, or attachable to, the hands, arms, feet or legs held by, or attachable to, the hands or feet
  • A63B31/11—Swim fins, flippers or other swimming aids held by, or attachable to, the hands, arms, feet or legs held by, or attachable to, the hands or feet attachable only to the feet
• • A—HUMAN NECESSITIES
  • A63—SPORTS; GAMES; AMUSEMENTS
  • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
  • A63B31/00—Swimming aids
  • A63B31/08—Swim fins, flippers or other swimming aids held by, or attachable to, the hands, arms, feet or legs
  • A63B31/14—Swim fins, flippers or other swimming aids held by, or attachable to, the hands, arms, feet or legs with valve-flaps
• • A—HUMAN NECESSITIES
  • A63—SPORTS; GAMES; AMUSEMENTS
  • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
  • A63B31/00—Swimming aids
  • A63B31/08—Swim fins, flippers or other swimming aids held by, or attachable to, the hands, arms, feet or legs
  • A63B31/10—Swim fins, flippers or other swimming aids held by, or attachable to, the hands, arms, feet or legs held by, or attachable to, the hands or feet
  • A63B31/11—Swim fins, flippers or other swimming aids held by, or attachable to, the hands, arms, feet or legs held by, or attachable to, the hands or feet attachable only to the feet
  • A63B2031/115—Swim fins, flippers or other swimming aids held by, or attachable to, the hands, arms, feet or legs held by, or attachable to, the hands or feet attachable only to the feet with blade at an angle to the plane of the foot when in use, e.g. to reduce plantar flexion
• • A—HUMAN NECESSITIES
  • A63—SPORTS; GAMES; AMUSEMENTS
  • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
  • A63B2225/00—Miscellaneous features of sport apparatus, devices or equipment
  • A63B2225/01—Special aerodynamic features, e.g. airfoil shapes, wings or air passages

Definitions

• the present invention relates to swim fins and particularly to fins having each at least one single- piece longitudinal member attached to the front of the foot pocket, with a blade part attached to such longitudinal member and consisting of one or more flap elements .
• the foils which are also rigid, also rotate about two axes, inserted in the two longitudinal members, also rigid, and their rotation is limited both by locks integral with the longitudinal members and by webs made of rubberized fabric which are connected both to the longitudinal members and to the ends of the rigid foils.
• the rotational movement is obviously caused by the airflow generated by kicking strokes, but the orientation of the foils cannot be controlled throughout the kicking stroke to be at the best angle of attack a° .
• the invention has the object of providing improved swim fins that can provide, with the same physical effort, a greater transformation of the force exerted by the forward-propelling body.
• the invention fulfills the above object by the provision of swim fins as defined in the main claim 1.
• Fig. 1 shows a plan view and a side view of a first embodiment, relating to a fin with constant- chord flaps .
• Fig. 2 shows the plan view and the side view of a further embodiment, relating to a fin with tapered flaps and the detail of the bent and twisted flap.
• Fig. 3 shows the plan view and the side view of a further embodiment, relating to a fin with two longitudinal members and arrow-shaped flaps.
• Fig. 4 is a detail view of a constant-chord flap embedded in the longitudinal member.
• Fig. 5 shows the bent longitudinal member with the flap embedded therein and aligned with the longitudinal axis of the longitudinal member to form an angle ⁇ ° .
• Fig. 6 shows the constant-chord flap with a diagram D, with the projection of the deformed shape of the bent flap.
• Fig. 7 is an axonometric view of the detail of the deformed shape of the flap with the diagram D.
• the fins 1 of the present invention are composed of a closed or open foot pocket 2 having a string or an adjustable strap.
• the front of the aforementioned foot pocket 2 has the root of a longitudinal member 3 permanently attached to its end, such member being adapted to bend about axes 11 perpendicular to the axis 9 and perpendicular to the plane of symmetry 10 where the orientation of the orthogonal foil section of the longitudinal member 3 opposes the lowest resistance.
• the foil sections are so designed as to provide a programmed cylindrical deformed shape 20 for the longitudinal member 3.
• a series of sheet-like flaps 4 are attached to each of the two lateral surfaces of the aforementioned longitudinal member 3, and may be parallel although independent of each other. Their apexes are free, whereby they are able to move vertically up or down relative to the axis 9 of the longitudinal member 3.
• the section of the flaps may have any foil profile .
• these sheet-like flaps 4 have sections with orthogonal airfoils 17 and efficient airfoils 18, whose foci 7 on their chords 5 or 6 are obviously situated on their longitudinal axis 8. Nevertheless, as discussed above, in certain alternative variant embodiments, the flaps may also have different foil profiles, particularly other than airfoils .
• foils 17 and 18 may be either symmetric or asymmetric.
• the flaps 4 may also have different foil profiles along the same flap 4 and generally have a tapering thickness toward their apex.
• the aforementioned flaps 4 are attached at their root to the two sides of the longitudinal member 3 and form a supplementary acute angle ⁇ ° with their own longitudinal axis 8 and with the longitudinal axis 9 of the longitudinal member, which opens away from the foot pocket 2.
• the longitudinal axes 8 of the flaps 4 may also not be straight, with a different angle ⁇ ° being formed for each point of the longitudinal axis 8 between the tangent on the curvilinear longitudinal axis 8 of the flap 4 and the straight longitudinal axis 9 of the longitudinal member 3.
• the foot pocket 2 the longitudinal member 3 and the flaps 4 generally form a one-piece unit manufactured by a single molding step.
• the fins 1 are composed of foot pockets 2, which can receive therein, by means of suitable quick connectors 21, assemblies of the longitudinal member 3 and the flaps 4 having different hydrodynamic properties to best fit the needs of scuba diver.
• a further embodiment of the fins 1 consists of a foot pocket 2, two longitudinal members 22 attached to each side of the foot pocket 2 and a series of flaps 23 which have a peculiar arrow shape, whose distal ends of their branches are elastically joined to the inner walls of the two longitudinal members 22.
• the branches of the flaps 23 will bend about axes perpendicular to the axis of symmetry 10 of the foot pocket 2 under moments MP equal to the summation of their lifts dP times their respective distances 1, i.e. : P x 1 x cos (1/2 interior angle of the arrow) , with 1 being equal to the distance between the dPs and the tip of the arrow level 25 with the common focus 7 of the two branches.
• the flaps may be also designed to be independent of the longitudinal member/s and connected thereto by means of elastic articulations, characterized by having one or more degrees of freedom.
• each fin 1 is equipped with a hydrodynamic assembly consisting of a single straight and elastic longitudinal member 3 with sheet-like flaps 4 attached at its sides and free at their ends, whose sections are airfoils 17 orthogonal to the longitudinal axis 8 or efficient airfoils 18 having the same axis 8, which forms a supplementary acute angle ⁇ ° with the longitudinal axis 9 of the longitudinal member 3, but also on the synergistic hydrodynamic behavior of the longitudinal member 3 and the flaps 4 attached thereto.
• This flow may be essentially deemed to consist of two flows :
• the flow generated by the fins 1 may be in turn divided, to simplify calculations, into two components: a horizontal component and a vertical component which reverses its direction at each half kicking cycle.
• the resultant of these components of the three flows deforms by reaction the flaps 4 and hence the longitudinal member 3 such that the flow thereby generated may impact the flaps 4 with the best possible angle of attack a° .
• the simultaneous deformations of the longitudinal member 3 and the flaps 4 caused by the kicking strokes are those that correspond to the deformation of the programmed synergistic hydrodynamic attitude of the longitudinal member 3 providing the best possible angle of attack a° of all the flaps 4.
• Such optimization is only limited by the areas close to the embedment of the flaps 4 in the longitudinal member 3, where deformations are necessarily limited and there is an excessive angle of attack a° .
• a further important feature is the provision of a supplementary acute angle ⁇ ° between the longitudinal axis 8 of the flaps 4 and the longitudinal axis 9 of the longitudinal member 3.
• chords 6 of the efficient airfoils 18 have a slope ⁇ ° of arcsin ( (l/2*chord 6*cos9° *tg5° ) /chord6) , if the curve falling between the point H and the point h has the same radius. This slope necessarily affects, i.e. reduces, the angle of attack a° .
• Another important feature relates to the angle of torsion ⁇ ° about the longitudinal axis 8 of the flap 4 embedded in the longitudinal member 3, with an angle ⁇ ° being significantly formed between the axis 8 and the axis 9, such angle providing a torsional moment component, orthogonal to the longitudinal axis 8, which progressively reflects, along the axis 8, into a decrease ⁇ ° of the angle of attack a° .
• the moments of some of the airfoils 18 might be usefully used, due to their coefficients Cm, whether different foils are used for the various flaps 4 or different values are taken relative to the angles of attack of the lift.
• the foils 18 will advantageously have an orientation that will allow proper utilization thereof during the downward kicking stroke. If the velocity vector of the flow is known, then the moment will be easily determined with the known relationship, and hence the corresponding angular deflection ⁇ ° which will cause a torsion of ⁇ ° degrees according to the resistance opposed by the sections of the foils.
• the most industrially interesting embodiment consists in a fin 1 having a foot pocket 1 with the root of a flexible longitudinal member 3 incorporated at its front, such member being able to bend up and down and having sheet-like flaps incorporated at its sides and shaped with airfoil sections 17, 18.
• These flaps 4 are only stably fixed by their roots on the two sides of the longitudinal member 3, whereas their longitudinal axis 8 forms a supplementary acute angle ⁇ ° with the longitudinal axis 9 of the longitudinal member 3.

Landscapes

• Health & Medical Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Physical Education & Sports Medicine (AREA)
• Footwear And Its Accessory, Manufacturing Method And Apparatuses (AREA)
• Toys (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=58765870

Family Applications (1)

Country Status (2)

Cited By (1)

Citations (2)

• 2016
  • 2016-04-06 CH CH00443/16A patent/CH712321A2/it not_active Application Discontinuation
• 2017
  • 2017-04-05 WO PCT/IB2017/051954 patent/WO2017175151A1/en not_active Ceased

Patent Citations (2)

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