JPH01131678A - Foot fin - Google Patents

Abstract

PURPOSE: To enhance a propelling efficiency by effectively preventing the generation of a resisting vortex as resistance on the periphery of a footweb part by making the width and the projection area of the footweb part satisfy a specified relation to let a water flow run along a foot fin. CONSTITUTION: A footweb part 1 and a foot placing part 2 are integrally made of rubber or a rubber-like elastic material. The plane of the footweb part 1 is made roughly semi-oval in shape and a free end part of the footweb part 1 to be separated from a heel strap 3 is removed in a roughly semicircular form. The width of the footweb part 1 is represented by b(mm) and the projection area thereof by S(mm<2> ) and when a ratio λ (=b<2> /s) thereof is changed as parameter to meet λ>1, preferably λ>=1.5 or more, the generation of a vortex is reduced. As the λ is increased gradually, the width (b) of the footweb part grows. Thus, preferably, the width (b) is selected in a range of 150<=b<=500 and λ in a range of 1.0<λ<=2.5.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to flippers used for diving, swimming, etc., and in particular to flippers that can efficiently convert the movement of the lower limbs into propulsive force. be.

(Prior Art) A foot pad that has been widely used in the past has a webbed part 1 and a foot insertion part integral with the webbed part 1, as shown in FIG. 4(a), for example. 2, and rubber heel straps 3 whose end portions are connected to both sides of the foot insert 2, and which normally extend in the direction of water flow (the direction indicated by arrow A in the figure). It has an elongated shape. Note that reference numeral 4 is a fastening fitting for connecting the heel strap 3 to the foot insert 2.

(Problems to be Solved by the Invention) However, in conventional flippers, as schematically shown in FIG. It is known that relatively large vortices are generated. The part where such a vortex is generated has a lower pressure than the pressure near the foot insertion part 2, so a vortex is generated due to this pressure difference, and this vortex acts on the flippers as resistance. , which caused the propulsion efficiency to decrease.

The present invention was made in view of such problems,
It is an object of the present invention to provide a flipper with low resistance and excellent propulsion efficiency as described above.

(Means for solving the problem) In order to achieve this object, the invention of this application includes at least a foot insertion part and a webbed part, and the webbed part has a width b.
, when the projected area is S, satisfies the relationship λ=b''/S>1.

(Function) When the webbed part satisfies the relationship λ>■, the generation of vortices along the lateral edges of the webbed part is suppressed, and therefore the resistance acting on the flippers is reduced.

(Embodiment) FIG. 1 is a perspective view showing a first embodiment of the present invention. Components having the same function as the symbols shown in FIG. 4(a) are indicated by the same symbols. 2 is a webbed part, 2 is a foot-socket part, 3 is a heel strap, and 4 is a fastening fitting for connecting the heel strap to the foot-socket part.

In this embodiment, the webbed part 1 and the foot insertion part 2 are integrally formed.
Constructed of rubber or rubber-like elastic material.

The planar shape of the webbed part 1 is approximately semi-elliptical, and the protruding end of the webbed part 1 separated from the heel strap 3 is removed to form a substantially semicircular shape.

In this embodiment, the width of the webbed portion 1 is b (mm), the projected area is 5 (I11...2), and the ratio λ
(-b2/S) was changed as a parameter to investigate the generation of vortices in the webbed part and eventually in the flippers, and it was found that λ
It has been found that the generation of vortices is reduced when >l, preferably λ>1.5 or more. However, as λ gradually increases, the width of the web also increases, so the width is selected within the range of 150≦b≦500, and λ≦2.5.
Therefore, λ is 1.0<λ≦
It is preferable to select it so that it is in the range of 2.5.

FIG. 2 is a perspective view showing another embodiment of the invention,
There is no difference in operation from the embodiment shown in FIG. 1, except that the webbed part 1 and the footrest part 2 are connected via a connecting rod 5 made of synthetic resin or rubber material.

Note that the web portion may have various shapes, some of which are schematically shown in FIGS. 3(a) to 3(e). Further, for the sake of simplicity, in the case of a device having a foot insert 2 and a rod 4, the rod is also omitted from the illustration. For comparison, a conventional flipper is shown in FIG. 3(f).

Note that the present invention is not limited to these embodiments, and various modifications can be made within the scope of the claims.

(Effects) As detailed above, according to the flippers of the present invention, water flows along the flippers, effectively preventing the generation of vortices that act as resistance at the periphery of the flippers, and improving propulsion efficiency. In addition, its length is shorter than that of conventional flippers, making walking easier.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of the present invention, and FIG. 2 is a perspective view showing an embodiment of the present invention.
Perspective views showing other embodiments of the present invention, FIGS. 3(a) to 3(e)
) is a diagram schematically showing the planar shape of the webbed part suitable for the present invention, FIG. 3(f) is a reference diagram showing a conventional flipper, and FIG. 4(
Figures a) and (b) are schematic diagrams showing conventional flippers and their state of use. 1... Webbed part 2... Foot insertion part 3...
・Heel strap 4... Fastening fittings Fig. 1 Fig. 2 Fig. 3 (H) (b) (C) (d) (e) (f)

Claims (1)

[Claims] 1. When the web has at least a foot part and a webbed part, and the width of the webbed part is b and the projected area is S, then λ=b^2
A flipper characterized by satisfying the relationship: /S>1.