RU215089U1 - FIN FOR SWIMMING - Google Patents

Abstract

The utility model relates to devices for swimming, underwater movement and muscle training and can be used in the construction of a fin worn on the foot. The swimming fin contains a device 1 for attaching to the swimmer's foot and a blade 2 connected to it, including an elongated bracket 5 and at least two water-blown blades 7, 8. The blades 7, 8 are pivotally mounted on an elongated bracket 5 on both sides of it with the possibility rotation relative to the longitudinal axis 9 of the elongated bracket 5 in both directions at a given angle. The elongated bracket 5 bends relative to the device 1 for fastening to the swimmer's foot during the flipper swing. The device 1 for attaching to the swimmer's foot is provided with a sole reinforcement 26, to which an elongated bracket 5 is connected. The elongated bracket 5 can be made elastically deformable and rigidly connected to the sole amplifier 26. In another embodiment, the elongated bracket 5 can be made resiliently deformable and attached to the sole reinforcement 26 by means of a hinge 27 with a return spring 30. The technical result of the utility model is to increase the efficiency of the fin. 8 w.p. f-ly, 12 ill.

Description

The utility model relates to devices for swimming, underwater movement and muscle training and can be used in the construction of a fin worn on the foot.

A flipper is known, described in the patent of the Russian Federation for the invention No. 2075320 C1 (published on March 20, 1997).

The fin contains a foot pocket and a rowing device, which has two longitudinal side ribs and transverse hydraulic blades attached between the ribs. The connecting element between the galoshes and the rowing device ensures the rotation of the rowing device relative to the horizontal axis in both directions from the initial position with an elastic return to the initial position. Both side ribs may contain a number of weakening to ensure the bending of the blade during operation. The rigidity of the side ribs continuously or discretely decreases towards the trailing edge of the propulsion device.

The described construction of the flipper ensures the rotation of the hydraulic blades at a slight angle only in conjunction with the longitudinal ribs, which is possible only with significant effort. Various types of rubbers and/or thermoplastic elastomers used to make fins have elastic properties, but not enough to allow the side ribs to rotate through a significant angle to provide high fin performance. Significant weakening of the connecting sections will allow the side ribs to rotate through a significant angle, but may, with constant bending, lead to their accelerated destruction.

The utility model patent of the Federal Republic of Germany No. 202007004633 U1 (published on October 25, 2007) describes a fin made in the form of a single complex part, consisting of a foot mount and a blade containing a set of transverse blades located at a distance from each other between two sidewalls connected to the bow of the foot attachment. The blades are installed with the possibility of elastic deviation during operation relative to the sidewalls in both directions from the neutral position, in which the geometric axes of the blades cross sections coincide.

In the considered design, the deviation of each blade is carried out due to the elastic deformation of the weakened section of the connecting section between the blade body and the bridge between the sidewalls of the propulsion device. Various types of rubbers and/or thermoplastic elastomers used to make fins have elastic properties, but not to a sufficient extent that would allow the blades to rotate through a significant angle to ensure high efficiency of the fin. Significant weakening of the connecting section will allow the blades to rotate through a significant angle, but may, with constant bending, lead to its accelerated destruction.

Known flipper, described in US patent for invention No. 8926385 B1 (publ. 01/06/2015), consisting of a mount for the foot and a propeller blade containing a set of transverse blades located at a distance from each other between two longitudinal side bars connected to the bow of the foot attachment. The blades are installed with the possibility of rotation relative to the side rails in both directions due to the hinge fastening on both sides to the side rails, while the hinges are located in a part made of elastic material connected to the blade and the side rail and tending to keep the blade in a neutral position. The edges of the blades and side rails are connected by flexible fabric bridges that open when the blade turns and hold the blade at the maximum angular deviation in both directions from the neutral position during the operation of the flipper.

The described flipper design has complex hinges made of a combination of axles and parts made of elastic material. Also, the design is complex in terms of assembling the longitudinal side slats with hinges and flexible fabric jumpers. In addition, the presence of a large number of flexible fabric jumpers will lead to a significant deterioration in the hydrodynamic resistance of the fin, especially when the swimmer glides in the water.

From US patent No. 4944703 (publ. 06/31/1990) a fin is known, consisting of a fastener for the foot and a blade containing a set of transverse blades located at a distance from each other between two side bars connected to the nose of the fastener for the foot. The blades are installed with the possibility of rotation relative to the side bars in both directions from the neutral position, in which the axes of the cross sections of the blades coincide. The flipper is equipped with devices for limiting the rotation of each blade in both directions and returning the blade to a neutral position. The limitation and return device is formed by a figured recess in the side bar of the propulsion device and a protrusion fixed on the end of the blade located in the recess, through which the axis of rotation of the blade passes. On the ledge, there are thrust zones to limit the rotation of the blade and an elastic tongue to return the blade to the middle position.

In the considered design, hinges with a return mechanism that are very difficult to manufacture are used. These hinges with return mechanisms, in addition to high cost, have small parts that will become clogged with sand and algae, which reduces the reliability of their operation.

A common disadvantage of the fins described above is their increased hydrodynamic resistance due to the presence of two side rails in the rowing device, which also leads to an increase in mass and the need to strengthen the junction of the blade with the foot mount.

An auxiliary device for swimming is known, described in US patent No. 3084355 (published on 04/09/1963), consisting of a foot mount and a blade formed by a base with transverse rotary blades. The base is made of rods joined to each other at an obtuse angle, coming out of the toe of the foot attachment, the first in its continuation parallel to the sole, and the second down from the sole with a slight inclination towards it. The edge of the base, facing away from the foot and forming an obtuse angle, is stepped on each rod, each transition zone between the steps is provided with a transverse double-sided axis, on which a rotary blade with a central edge cutout is installed on both sides of the rod for free rotation on the rod. The edges of the blade adjacent to the cutout are formed in the form of loops, covering both sides of the axle with a gap, thus, each blade is mounted on the axle with its edge.

The operation of the described device is designed for the rotational movement of the swimmer's legs under water, while the center of rotation, in a particular case, is the knee joint.

When the swimmer's leg rotates down, the blades of the first rod, on which the water pressure is carried out behind the axes, turn on the axes under the pressure of the water so that their total area is minimal in the direction perpendicular to the pressure, respectively, the resistance is minimal. The blades of the second rod at the same time perceive the water pressure to the axes and tend to turn in the direction opposite to the pressure, but rest against the surface of the rod and form a common surface of the maximum area, through which the swimmer is repelled from the water.

When the leg is rotated upward, the blades of the second rod, on which the water pressure is carried out behind the axes, turn on the axes under the pressure of the water so that their total area is minimal in the direction perpendicular to the pressure, respectively, the resistance is minimal. The blades of the first rod at the same time perceive the water pressure to the axes and tend to turn in the direction opposite to the pressure, but rest against the surface of the rod and form a common surface of the maximum area, through which the swimmer is repelled from the water.

Thus, each of the rods of the base of the propulsion device works in only one direction, which reduces the effectiveness of the auxiliary device for swimming with a significant increase in its mass (inert properties) and resistance to movement in water. In addition, in the described device, you can only move in the water, to move along the bottom or on land, it must be removed due to the presence of a second rod protruding downward from the sole.

Also known is the technical solution of the flipper described in US patent No. 3081467 (published March 19, 1963), consisting of a fastening for the foot and a blade formed by a rod with transverse rotary blades. The shank operably extends from the toe of the foot binding down from the sole, but can be moved to a transport position up from the sole substantially parallel to the wearer's foot. The edge of the rod, facing away from the foot, is provided with transverse double-sided axes fixed in it, on each of which a rotary blade with a central edge cutout is installed on both sides of the rod for free rotation on the rod. Blade edges adjacent to the notch are formed in the form of loops covering both sides of the axle with a gap.

In another version, the blade can be made of two parts, each part is mounted on an axis on opposite sides of the rod. With this arrangement, means for centralizing the blades are provided to connect the two parts together so that rotation beyond the 180 degree limit is prevented and both parts function as one blade. In the example shown, the parts of the blade are connected to each other by means of a clamp located across the rod and limiting the movement of the blade against the rod.

The operation of the described flipper is designed for the swinging movement of the swimmer's legs under water.

When the swimmer's leg is bent, the blades of the rod, on which the water pressure is carried out behind the axes, turn on the axes under the pressure of the water so that their total area becomes minimal in the direction perpendicular to the pressure, respectively, the resistance is minimal.

When the swimmer's leg is extended, the blades of the rod perceive the pressure of the water to the axes and tend to turn in the direction opposite to the pressure, but rest against the surface of the rod and form a common surface of the maximum area, through which the swimmer is repelled from the water and rushes forward.

In the described solution, the shortcomings of the flipper design with two longitudinal side rails are significantly reduced, since the hydrodynamic resistance is significantly reduced using a single carrier rod with blades.

The technical problem of the design is the work of the considered flipper for repulsion in only one direction, in which either a completely closed area of interaction with water or a completely open area for returning to the pushing position is formed. Efficient use of such a flipper for the uniform movement of a swimmer who periodically moves his legs up and down is difficult.

The closest is the flipper technical solution described in the French patent No. 2931690 (published on December 4, 2009), which includes a foot pocket connected to one or more blades. The blade includes an elongated bracket with a cylindrical socket that passes through it perpendicular to its length, and a rowing device consisting of two streamlined blades, fixed with their end part on one side and the other on the axis, and the attack edge of the blades runs parallel to this axis. mounted with the possibility of rotation in the socket of the bracket.

For greater clarity, it is clarified that the terms "angle of attack", "edge of attack", "chord", "blade" are borrowed from aerodynamics.

The operation of the described flipper is designed for the swinging movement of the swimmer's legs under water. In this case, the blades will freely rotate about the axis until they rest against the limiter. Then the blades are repulsed from the water with the transfer of reactive force to the swimmer.

Although the description indicates that the angle of rotation of the blades changes automatically depending on the speed of the swimmer, no real automatic control mechanism is presented.

In the description of the flipper, a version of the design is presented, which includes blade rotation limiters, which are connected to a rod that moves inside the bracket and has a thread at the end, onto which a knurled roller is screwed for adjustment. It is also indicated that to change the angle of the blades, the swimmer must manually rotate the knurled roller at the end of the bracket. This will change the angle of inclination of the blades relative to the bracket.

To perform this operation, each time it will be necessary to stop moving in the water, stop and make this adjustment. It should be additionally noted that without removing the fin from the foot, it is not very convenient to do this.

In this technical solution, it is indicated several times that the bracket is made rigid in order to exclude deformation during the operation of the fin. A rigid non-deformable bracket is also necessary so that the mechanism for changing the angle of attack of the blades is not blocked. The description also says that the bracket has a downward slope of about 10 degrees relative to the sole of the foot. Such a design of the bracket significantly complicates the entry of the fins from land into the water, if they are worn on the foot.

All of the above patents state that the efficiency of the flipper is increased by using multiple blades mounted on one or two longitudinal bars (brackets).

A dyno was used to evaluate the efficiency of the flipper. The schematic diagram of the stand is shown in figure 12. The technique for evaluating the effectiveness of the flipper was as follows:

the test fin was installed on the lower horizontal bar of the stand;

the drive of the stand provided a constant frequency of strokes of the horizontal rod;

during the entire cycle, measurements were made of the angle of rotation of the horizontal rod, the magnitude of the force required to drive the stand, and the magnitude of the reactive force (push);

calculations of the efficiency of the flipper and plotting were carried out.

Comparative tests in the pool on a dynamometer showed that the fin made according to the description of the French patent No. 2931690 has a slight increase in efficiency compared to the modern classic fin (trademark AQUALUNG).

There are two main reasons for its low efficiency:

first - a modern classic fin is made using high quality modern materials and technologies and has good efficiency,

the second is the imperfection of the dynamics of a flipper with several blades fixed on one or two longitudinal bars (brackets), shown in figure 10. It can be seen from this figure that at the beginning of the swing of the flipper, the angle of attack of the blade is small. The flow of water G does not receive significant resistance when exposed to the blade. Further, as the flipper swings, the resistance of the blade to the flow of water increases. At the moment the flipper passes through the bisector of the angle of mach, the value of the reactive force reaches its maximum value. But after the flipper passes through the bisector, the value of the reactive force begins to decrease, and the resistance of the blade to the flow of water increases sharply. More clearly, the change in forces during the swing of the last is shown by the example of one blade in figure 11.

During the stroke, water pressure P acts on the blade surface. As a result, a force Q appears, which is directly proportional to the product of this pressure and the projection of the blade area

Q=k*P*S*Sinα,

where k - constant for a given flow rate, coefficient;

P - water pressure;

S - blade area;

α - angle of attack of the blade.

The direction of force Q is perpendicular to the plane of the blade. In this case, due to the force Q, a reactive force R arises, which is directed along the axis of motion forward. The value of the reactive force R is calculated by the formula

R=Q*Cosα.

During the swing of the flipper, the blade has to overcome the drag of the water. In this case, the drag force will be

F=Сх* Q,

where Cx is the drag coefficient.

The blades of the flipper for this case should be attributed to the plates, Cx will be close to "1". And, accordingly, we can take F=Q. The force applied to the flipper to overcome the drag F will be the expenditure of energy that is converted into reactive force R. Accordingly, the efficiency η of the blade(s) will be calculated by the formula

η=R/Q.

The three diagrams (a, b, c) of figure 11 clearly show that the blade efficiency is greatest at the beginning of the fly-fin. Then, in the middle of the last swing (diagram b), we have the greatest value of the force R, with a simultaneous decrease in efficiency. Further, the reactive force R decreases, and the drag force increases rapidly, leading to a significant decrease in the efficiency of the blade.

Having performed simple calculations, we see that for the special case of circuit "a" the efficiency is η=0.88, for the special case of circuit b the efficiency is η=0.64, and for the special case of circuit c the efficiency is η=0.34. This shows that it is precisely the sharp decrease in efficiency after the flipper has passed the bisector of the fly angle that leads to the insufficient efficiency of such a flipper with several blades as a whole. Here are the results of the ideal efficiency calculations. Real efficiency is always less than ideal.

All this shows that the increase in the efficiency of the flipper declared in the French patent No. 2931690 is not implemented enough, which is the technical problem of the considered design, taken as a prototype.

The indicated technical problem in a flipper for swimming, containing a device for attaching to the swimmer's foot and a blade connected to the device for attaching to the swimmer's foot, containing an elongated bracket and at least two streamlined blades pivotally mounted on an elongated bracket on both sides of it with the possibility of rotation about the longitudinal axis of the aforementioned elongated bracket in both directions at a given angle, it is solved by bending the elongated bracket relative to the attachment device to the swimmer's foot during the flipper swing.

The foot attachment device typically comprises a reinforced outsole to which an elongated blade bracket is attached.

The elongated bracket is predominantly elastically deformable and is rigidly attached to the sole reinforcement of the foot attachment device.

The elongated bracket is preferably elastically deformable and can be connected to the sole reinforcement of the foot attachment device by means of a hinge. In this case, the hinge is advantageously provided with at least one return spring.

The longitudinal axis of the elongated bracket is oriented forward relative to the foot attachment device and is preferably located at an angle of 0° to 20° to the longitudinal axis of the foot attachment device.

The blades are usually mounted on an elongated bracket using a common axis.

The elongated blade bracket may be at least partially composed of modules with water-blown blades.

The elongated bracket, at least on its one side, is provided with at least one protrusion limiting the rotation of the water-cooled blade.

The technical result of the utility model is to increase the efficiency of the flipper.

The given set of features in comparison with the prior art allows us to conclude that the proposed technical solution complies with the condition of patentability "novelty". At the same time, the claimed technical solution is applicable in the design of a fin for scuba diving, so it meets the condition of "industrial applicability".

The inventive fin for swimming is shown in the following figures.

In FIG. 1 shows a fin in axonometric projection.

In FIG. 2 shows an explosion diagram of a flipper in axonometric projection.

In FIG. 3 shows a fin with a hinge connecting the sole reinforcement and an elongated bracket, side view.

In FIG. 4 shows the stages of the work of the flipper when swinging it down.

In FIG. 5a and fig. 5b shows how the flipper works when it is swung up and down.

In FIG. 6 shows a water-blown blade.

In FIG. 7a shows a fin with a rigid connection of the sole reinforcement and an elongated bracket, side view.

In FIG. 7b and 7c are diagrams of the operation of the flipper as it swings upwards under elastic deformation of the elongated blade arm.

In FIG. 8 shows the inventive fin with a modular design of the blade.

In FIG. 9 shows a variant of the collapsible design of the flipper.

In FIG. 10 shows the steps of the prototype flipper according to French patent No. 2931690 when swinging it down.

In FIG. 11 shows diagrams of applying forces to the blades of the prototype flipper according to French patent No. 2931690 at the stages of work when swinging them down.

In FIG. 12 is a schematic diagram of a fin test dynamometer.

In figures 1-12 adopted the following position numbers.

1 - device for attaching to the swimmer's foot;

2 - blade;

3 - a device for attaching to the swimmer's foot, made in the form of a galosh;

4 - device for attaching to the swimmer's foot, made in the form of a pocket with fixing straps;

5 - elongated bracket;

6 - toe of the fastening device;

7 - 7i, 8 - 8i - streamlined blades;

9 - longitudinal axis of the elongated bracket/

10 - longitudinal axis of the attachment device to the swimmer's foot;

11 - module with water-blown blades;

12 - 12i - holes in the elongated bracket;

13 - 13i - common connecting rotating axis of the water-cooled blades;

14 - plane of symmetry of the blade;

15 - swing movement of the swimmer's leg up;

16 - swing movement of the swimmer's leg down;

17 - leading edge (edge of attack) of a streamlined blade;

18 - trailing edge of the water-cooled blade;

19 - axis of rotation of the streamlined blade;

20 - lateral edge of the water-cooled blade;

21 - streamlined surface of the blade;

22 - the length (chord) of the water-cooled blade;

23 - width of the streamlined blade;

24 - through holes for water bypass;

25 - 25i - protrusions on an elongated bracket, forming limiters for the rotation of the streamlined blades;

26 - sole reinforcement;

27 - hinge;

28 - eye;

29 - hinge axis;

30 - return spring;

31 - stabilizer;

32 - connecting device;

33 - flipper drive;

34 - flipper angle sensor;

35 - torque heads;

36 - horizontal bar;

37 - vertical bar;

38 - test fin;

39 - vertical thrust;

40 - stand frame;

41 - control device;

42 - recording device;

α - angle of attack of the blade;

β ₁ , β _2i , β ₃ …β _i - the angles formed between the plane of symmetry of the blade and the longitudinal axis of the elongated bracket in their rigid design when swinging the flipper up;

γ ₁ , γ _2i , γ ₃ ... γ _i - the angles formed between the plane of symmetry of the blade and the longitudinal axis of the elongated bracket in their rigid design when swinging the flipper down;

ϕ - the angle of deviation of the axis of the elongated bracket from the bisector of the angle of the flapper.

The fin consists of a device 1 for attaching to the swimmer's foot and a blade 2 connected to the device 1 for attaching to the foot.

The device 1 for attaching to the foot is preferably made of rubber and/or thermoplastic elastomer in the form of overshoes 3 (Fig. 1), but there may be other versions, for example, in the form of a pocket (half overshoes) 4 with a set of fixing straps (Fig. 2).

The device 1 fastening to the foot is made with a rigid sole and may for this purpose contain an amplifier 26. The amplifier 26 of the sole can be made integral with the galoshes 3 of a polymeric material, and can also be made of any other material, for example, metal, polymer, reinforced with carbon and / or other fibers, plywood, fiberglass, etc. In this case, such reinforcement 26 can be attached to the sole of the foot attachment device 1 using rivets, threaded connections, glue, welding and/or poured into the "body" of the sole of the foot attachment device 1. The front part of the foot attachment device 1 contains an eyelet 28 for attaching an elongated bracket 5.

The blade 2 contains an elongated bracket 5, oriented forward relative to the toe 6 of the fastening device 1, and at least two water-blown blades 7, 8. The longitudinal axis 9 of the elongated bracket 5 along its long side is predominantly parallel to the longitudinal axis 10 of the overshoe 3, but can also be located under an angle of up to 20° to the longitudinal axis 10 of the overshoe 3. The elongated bracket 5 can be attached to the foot attachment device 1 (Fig. 3) using the hinge 27.

The hinge 27 consists of an eyelet 28, which can be part of both an elongated bracket 5 and a foot attachment device 1, as well as a counterpart of the hinge 27 and an axle 29 connecting them. The hinge 27 allows the elongated bracket 5 to pivot relative to the foot attachment device 1. While the longitudinal axis 9 of the elongated bracket 5 can change its position relative to the longitudinal axis 10 of the device 1 attachment to the foot.

The hinge 27 is usually provided with at least one return spring 30. The return spring 30, directly or as part of a spring device, returns the elongated arm 5 to its middle starting position after the end of the leg swing. The characteristic of the spring 30 or spring device is selected in such a way as to ensure the efficient use of the efforts of the swimmer. The characteristic of the spring 30 or spring device can be either linear or non-linear.

The elongated bracket 5 is preferably elastically deformable (Fig. 7a, Fig. 7b, Fig. 7c).

For resiliently deformable bracket 5, it is also possible to rigidly attach to the device 1 fastening to the foot, for example, by means of a connecting device 32. In this case, the longitudinal axis 9 of the elongated bracket 5 is bent together with the elongated bracket 5 relative to the longitudinal axis 10 of the device 1 fastening to the foot due to the elastic deformation of the elongated bracket 5 during the swing of the foot and/or due to the presence of a weakened area on the elongated bracket 5.

The elongated bracket 5 is usually made in one piece, but at least partially, it can be assembled from several modules 11 (Fig. 8) with water-blown blades 7i, 8i.

The elongated bracket 5 is provided with at least one stabilizer 31 in the form of an end extension in a plane perpendicular to the axis 19 of rotation of the streamlined blades 7 - 7i, 8 - 8i.

The elongated bracket 5 can be made of metal, polymer reinforced with carbon and/or other fibers, plywood, fiberglass, etc.

The streamlined blades 7, 8 are pivotally mounted on an elongated bracket 5 on both sides of it on a common connecting rotating axis 13 located in the hole 12, as a rule, with the possibility of joint rotation of the streamlined blades 7, 8 together with the axis 13 connecting them relative to the above-mentioned elongated bracket 5 in both directions at a given angle. As a rule, rotation in one direction is possible at an angle βi between the longitudinal axis 9 of the elongated bracket 5 along its long side and the symmetry plane 14 of the i-th streamlined blade 7, 8 when the swimmer's leg swings 15 upwards. In the other direction, the rotation is possible at an angle γ _i between the named axis 9 and the plane 14 with the swing 16 of the swimmer's foot down. In this case, the symmetry plane 14 of the i-th streamlined blade 7, 8 passes through the leading edge 17 of the blade 7, 8, its trailing edge 18 and the rotation axis 19 of the blade 7, 8. The angles β _i and γ _{i of} rotation of the blades 7 - 7i, 8 - 8i may differ for the paddles located near the foot attachment device 1 and those located at the far end of the bracket 5 of the blade 2 of the fin.

In a particular case, the streamlined blades 7, 8 can be made removable from the elongated bracket 5. The shape of the streamlined blades 7, 8 is predominantly trapezoidal in plan with rounded corners, but may also have a different shape. Each streamlined blade 7, 8 has a leading edge 17 (attack edge) facing the foot attachment device 1, a trailing edge 18, two side edges 20 and two streamlined surfaces 21 between them (Fig. 6). A common connecting rotating axis 13 is inserted into each streamlined blade 7, 8, located in the first third of the length 22 (chord) of the blades 7, 8 from the side of the leading edge 17.

The leading edge 17 of the blade is curved and/or straight, but located at an angle to the axis 19 of rotation of the blade 7, 8. The leading edge 17 of the blade 7, 8 can also be made in the form of a broken line.

The streamlined blades 7, 8 on one side of the elongated bracket 5 can be the same or different in size, for example, in length 22 and/or width 23, with the streamlined blades 8, 7 on the other side of the elongated bracket 5. The blades 7, 8 can be equipped with through holes 24 for bypassing water and reducing pressure on the blades 7, 8.

The common connecting rotating axis 13 of the water-blown blades 7, 8 can also serve to increase the rigidity of the above-mentioned blades. In this case, the aforementioned axle 13 is inserted into the blade 7, 8 to a considerable depth.

The blade 2 is usually equipped with two or more pairs of water-cooled blades 7 - 7i, 8 - 8i. In this case, the dimensions of each pair of water-blown blades are preferably the same, but can be different, both for all pairs and for one or more pairs. The streamlined blades 7, 8 are predominantly rigid, retaining their shape when exposed to water flow, however, they can be made elastic with the possibility of bending in the longitudinal and/or transverse directions relative to the longitudinal axis 9 of the elongated bracket 5 along its long side.

The blade 2 is equipped with a limiter for turning the streamlined blades 7, 8 at a predetermined angle, preferably together with a common connecting rotating axis 13 connecting them. streamlined blades 7, 8 in the extreme position of its rotation (Fig. 5a, 5b). The protrusion 25 on the elongated bracket 5 is preferably cylindrical on the side of the elongated bracket, but may have a different shape. As a rule, each pair of streamlined blades 7 - 7i, 8 - 8i corresponds to a ledge 25 - 25i.

It is possible to perform limiting protrusions 25 on opposite sides of the elongated bracket 5 for each hydrofoil blade 7 or 8, at least one protrusion 25 on different sides relative to the axis 19 of rotation of the hydrofoil blades 7, 8. The protrusions 25 can be made integral with the elongated bracket 5 or mounted on it as separate parts.

A rubber material can be applied to the limiting rotation of the blade 7, 8 ledge 25 to soften the contact of the blade 7, 8 with the ledge 25. Also, another material can be used for this, providing damping of the contact. The ledge 25 itself on the elongated bracket 5 can be made entirely of a material that provides damping and/or softening of the contact between the blade 7, 8 and the limiting ledge 25.

In a particular case, the fin can be made of materials with positive buoyancy.

Last works as follows.

The swimmer in the process of moving in the water makes swings 15 up and swings 16 down, shown in Fig. 4, 5a, 5b, 7b.

During the stroke 15, when the flipper moves upwards, under the action of water pressure, the streamlined blades 7, 8 turn by an angle Pi (similarly to Fig. 6a).

The blades 7, 8, when turning in the extreme position, rest against the limiting ledges 25 located on the elongated bracket 5. Then the blades 7, 8 are repelled from the water, transmitted to the swimmer through the elongated bracket 5 and the device 1 for attaching to the foot. Further, when the flipper moves upwards, the water pressure on the blade 2 increases due to the fact that the angle of attack of the streamlined blade 7, 8 has increased. Under the action of increased water pressure, the elongated bracket 5 is elastically deformed and its longitudinal axis 9 is bent relative to the device 1 fastening to the foot. Due to the bending of the elongated bracket 5, the angle of attack of the streamlined blade decreases, which leads to a decrease in the resistance of the blade 2 and an increase in the reactive force. Further, as the flipper performs and the water pressure on the blade 2 continues to increase, the elongated bracket 5 elastically bends to an even greater angle relative to the foot attachment device 1, thus reducing the angle of attack of the blade 7, 8. This makes it possible to reduce the resistance of the blade 2 and increase push force. When the flapping movement of the fin stops, the elongated bracket 5 is elastically straightened, and the blade 2 returns to its original position relative to the foot attachment device 1, providing an additional impetus to the swimmer.

Then, during the stroke 16, when the flipper moves down, under the action of water pressure, the streamlined blades 7, 8 rotate through an angle γ _i (similarly to Fig. 5b). The blades 7, 8, when turning in the extreme position, rest against the limiting ledges 25 located on the elongated bracket 5. Then the blades 7, 8 are repelled from the water, transmitted to the swimmer through the elongated bracket 5 and the device 1 for attaching to the foot. Further, when the flipper swings upwards, the water pressure on the blade 2 increases due to the fact that the angle of attack of the streamlined blade has increased. Under the action of increased water pressure, the elongated bracket 5 is elastically deformed and its longitudinal axis 9 is bent relative to the device 1 fastening to the foot. Due to the bending of the elongated bracket 5, the angle of attack of the streamlined blades 7, 8 decreases, which leads to a decrease in the resistance of the blade 2 and an increase in the reactive force. Further, as the flipper performs and the water pressure on the blade 2 continues to increase, the elongated bracket 5 elastically bends to an even greater angle relative to the foot attachment device 1, thus reducing the angle of attack of the blade 7, 8. This makes it possible to reduce the resistance of the blade 2 and increase reactive force. When the flapping movement of the fin stops, the elongated bracket 5 is elastically straightened, and the blade 2 returns to its original position relative to the foot attachment device 1, providing an additional impetus to the swimmer.

In another version of the flipper, the resiliently deformable elongated bracket 5 can be attached to the foot attachment device 1 (Fig. 3) using a hinge 27.

During the swing 15, when the flipper moves up (Fig. 6a), under the action of water pressure, the streamlined blades 7, 8 rotate through an angle β _i . The blades 7, 8, when turning in the extreme position, rest against the limiting ledges 25 located on the elongated bracket 5. Then the blades 7, 8 are repelled from the water, transmitted to the swimmer through the elongated bracket 5 and the device 1 for attaching to the foot. Further, when the flipper moves upwards, the water pressure on the blade 2 increases due to the fact that the angle of attack of the streamlined blade 7, 8 has increased. Under the action of increased water pressure, the elongated bracket 5 overcomes the force of the spring 30 and rotates in the hinge 27, through which it is attached to the device 1 for attaching to the foot. Due to the rotation of the elongated bracket 5, the angle of attack of the streamlined blade decreases, which leads to a decrease in the resistance of the blade 2 and an increase in the thrust force. Further, as the flipper performs and the water pressure on the blade 2 increases, the elongated bracket 5 rotates at an even greater angle relative to the foot attachment device 1, thus reducing the angle of attack of the blade 7, 8. This reduces the resistance of the blade 2. stops, then, under the action of the spring 30 of the hinge 27, the blade 2 returns to its original position relative to the attachment device 1 to the foot and provides an additional impetus to the swimmer.

Then, during the swing 16, when the flipper moves down (Fig. 5b), under the action of water pressure, the streamlined blades 7, 8 rotate through an angle γ _i . The blades 7, 8, when turning in the extreme position, rest against the limiting ledges 25 located on the elongated bracket 5. Then the blades 7, 8 are repelled from the water, transmitted to the swimmer through the elongated bracket 5 and the device 1 for attaching to the foot. Further, when the flipper moves down, the water pressure on the blade 2 increases due to the fact that the angle of attack of the streamlined blade 7, 8 has increased. Under the action of increased water pressure, the elongated bracket 5 rotates in the hinge 27, through which it is attached to the device 1 for attaching to the foot. Due to the rotation of the elongated bracket 5, the angle of attack of the streamlined blades 7, 8 decreases, which leads to a decrease in the resistance of the blade 2 and an increase in the reactive force. Further, as the flipper performs and the water pressure on the blade 2 increases, the elongated bracket 5 rotates at an even greater angle relative to the foot attachment device 1, thus reducing the angle of attack of the blade 7, 8. This reduces the resistance of the blade 2. stops, then, under the action of the spring 30 of the hinge 27, the blade 2 returns to its original position relative to the attachment device 1 to the foot and provides an additional impetus to the swimmer.

Presented flippers allows you to optimize the angles β and γ of rotation for each pair of blades 7 - 7i, 8 - 8i. In this case, smaller values of the angles β and γ of rotation of the blades 7 - 7i, 8 - 8i provide a greater impetus to the swimmer. And the large angles β and γ of rotation of the blades 7 - 7i, 8 - 8i contribute to the economical use of the swimmer's muscular strength.

Changing the position of the longitudinal axis 9 of the elongated bracket 5 relative to the longitudinal axis 10 of the device 1 for fastening to the swimmer's foot during flapping makes it possible to obtain high efficiency in the use of the swimmer's muscular strength.

The next element that increases the efficiency of the presented flipper is the elastic deformation of the blades 7, 8 under the influence of water pressure on it. The bend of the blade, increasing from the axis of rotation 19 to the trailing edge 18, helps to reduce its hydrodynamic resistance.

Also, a significant increase in the efficiency of the blades can be achieved by making bypass through holes 24 in the streamlined blades 7 - 7i, 8 - 8i (Fig. 6).

Changing the size of the area of the streamlined blades 7, 8 allows you to adjust the push pulse.

The use of only one elongated bracket 5 associated with the device 1 fastening to the swimmer's foot, provides a significant reduction in hydrodynamic resistance when swinging flippers.

Since the swimmer, when moving in the water, makes reciprocating movements with his legs, the mass of the flipper affects the inertia force that must be overcome during such a movement. The use of only one elongated bracket 5 makes it possible to reduce the mass of the fin, which also has a positive effect on the efficiency of using the swimmer's muscular strength.

Also, the use of only one elongated bracket 5 leads to an easy solution to the problem of disconnecting it from the toe-foot part of the device 1 fastening to the foot (Fig. 9). This disconnection reduces the overall size of the fin and makes it easier to transport to the place of use.

Unlike other designs, the use of only one elongated bracket 5 makes it easier to attach to it and detach from it the streamlined blades 7 - 7i, 8 - 8i. This makes it even easier to transport the fin to the point of use.

The ease of attachment and detachment of the 7 - 7i, 8 - 8i water-cooled blades allows the use of several blade sets with different characteristics. At the same time, the main part of the flipper (an elongated bracket 5 with a device 1 for fastening to the swimmer's foot) remains the same. The vane sets 7 - 7i, 8 - 8i are optimized: one for swimming with powerful pushing, the other for calm swimming with minimal energy consumption.

The proposed fin also provides for modularity of the design. This means that the basic construction of the fin contains, for example, three pairs of water-blown blades 7, 7a, 7b, 8, 8a, 8b and operates according to the principles outlined above. It is assumed that with 3 pairs of blades, calm swimming is performed with minimal energy consumption. And for the purpose of increasing the pushing power, an additional module 11 is installed with additional streamlined blades 7i, 8i (Fig. 8).

It is also easy to replace the return spring 30 or the spring device with others having different characteristics. It also allows you to get a fin with a powerful push or for a smooth swim.

It should be noted that the above embodiments are illustrative and not restrictive of the apparatus shown, and that those skilled in the art will be able to develop many alternative embodiments without departing from the scope of the appended claims. By itself, the fact that certain criteria are listed in mutually different dependent claims of a utility model does not indicate that a combination of these criteria cannot be used to obtain a positive effect.

Claims (9)

1. Fins for swimming, containing the attachment device to the swimmer's foot; a blade connected to the device for attaching to the swimmer's foot, containing an elongated bracket and at least two water-blown blades pivotally mounted on an elongated bracket on both sides of it with the possibility of rotation relative to the longitudinal axis of the above elongated bracket in both directions at a given angle, characterized in that the elongated the bracket bends relative to the attachment device to the swimmer's foot while swinging the fin. 2. A fin according to claim 1, characterized in that the device for fastening to the foot contains a sole with an amplifier, to which an elongated blade bracket is attached. 3. The fin according to claim 2, characterized in that the elongated bracket is elastically deformable and is rigidly attached to the sole reinforcement of the foot attachment device. 4. Fin according to claim 2, characterized in that the elongated bracket is elastically deformable and is connected to the sole reinforcement of the foot attachment device by means of a hinge. 5. A flipper according to claim 4, characterized in that the hinge is provided with at least one return spring. 6. Fin according to claim 1, characterized in that the longitudinal axis of the elongated bracket is oriented forward relative to the foot attachment device and is located at an angle of 0° to 20° to the longitudinal axis of the foot attachment device. 7. Fin according to claim 1, characterized in that the blades are mounted on an elongated bracket using a common axis. 8. The fin according to claim 1, characterized in that the elongated blade bracket is at least partially composed of modules with water-blown blades. 9. The flipper according to claim 1, characterized in that the elongated bracket, on at least one side of it, is provided with at least one protrusion that limits the rotation of the water-cooled blade.

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