JPH08117363A - Badminton racket - Google Patents

Abstract

PURPOSE: To obtain a higher flexibility by forming multiple ribs extending in the shaft axis direction at least at part of inner surface of the shaft of a badminton racket which is composed of a face, hollow shaft, and grip. CONSTITUTION: The badminton racket is designed such that a face part 5 is formed at the top end of a shaft 4, and a grigp 6 is formed at the base end. In the shaft 4, multiple ribs 4b, that extend in the longitudinal direction of the shaft 4, are projected at the inner surface of a hollow cylinder body 4a. The ribs 4b are formed only at side surfaces of the inner circumference of the hollow cylinder body 4a viewed from the front direction of the face part 5. The ribs 4b are formed only at portions and near the portions where the face part 5 and the hollow cylinder body 4a intersect in the inner circumference of the shaft. This increases a torsional rigidity of the shaft 4 as well as a swinging feeling.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a badminton racket, and more particularly to a badminton racket having a shaft portion with improved bending characteristics.

[0002]

2. Description of the Related Art As shown in FIG. 2, a badminton racket is provided with a face portion 2 at the tip of a shaft portion 1 and a grip portion 3 at the base end side. Conventionally,
The shaft part 1 of a widely used badminton racket is, as shown in FIG. 3, made of a hollow cylindrical member having a true circular cross section.

As another shaft section having another cross-sectional shape, as shown in FIG. 4, there is an elliptical shaft section 1A in which the major axis direction is arranged in a direction perpendicular to a surface including a face surface of the face section 2A.

As a shaft portion having another sectional shape,
As shown in FIG. 5, the width direction of the face portion (face portion 2
There is an elliptic shaft portion 1B in which the major axis direction is arranged in the direction including the face surface of B).

[0005]

The shaft of a badminton racket is required to have an appropriate flexibility when the badminton racket is shaken.
As shown in the figure, in the shaft portion 1 having a perfect circular cross section,
Since the bending rigidity in the direction along the face surface (B and B'directions in FIG. 2) and the bending rigidity in the direction perpendicular to the face surface (C and C'directions) are equal, when the racket is shaken, The shaft portion 1 easily bends in the direction along the axis. Also,
The torsional rigidity (D, D ') around the shaft center of the shaft portion 1 is also small.

The shaft portion 1A shown in FIG. 4 has the advantage that the air resistance when swinging the racket is small,
The bending in the direction perpendicular to the face surface is poor, and the bending rigidity in the direction along the face surface is small.

The shaft portion 1B shown in FIG. 5 has good bending in the direction perpendicular to the face surface, but since it is wide in the racket width direction, it has a large air resistance.

The shaft portions 1A and 1B shown in FIGS.
In both cases, the torsional rigidity around the shaft center of the shaft portion is not so much improved.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a badminton racket having a shaft portion having a good bending property.

More specifically, it is an object of the present invention to provide a badminton racket having a shaft portion which is improved in the direction perpendicular to the racket face surface and has a large rigidity in the direction along the racket face surface. To do.

[0011]

A badminton racket according to claim 1 is a badminton racket having a face portion, a hollow shaft portion, and a grip portion, and at least a part of an inner surface of the shaft portion has a shaft portion axis line. It is characterized in that a rib extending in a direction along the rib is provided.

A badminton racket according to a second aspect of the present invention is the badminton racket according to the first aspect, wherein the rib is provided only on a side surface portion of the shaft portion which is located laterally in a front direction of the face portion. It is characterized by that.

[0013]

By providing the rib, the bending rigidity and the torsional rigidity of the shaft portion are increased.

In the badminton racket of the second aspect, since the rib is provided only on the side surface of the shaft portion, the badminton racket is improved in the direction perpendicular to the face surface as compared with the direction along the face surface. The shaft portion does not need to be wide in the width direction of the face portion, and air resistance is small.

[0015]

EXAMPLES Examples will be described below with reference to the drawings. FIG. 1 (a) is a front view of a badminton racket according to an embodiment, FIG. 1 (b) is a sectional view taken along line BB of FIG. 1 (a), and FIG. 1 (c) is the same (b). ) Is a cross-sectional view taken along the line CC, and FIG. 1D is an enlarged view of the end face of the cut portion taken along the line BB in FIG.

Also in this badminton racket, the face portion 5 is provided on the tip side of the shaft portion 4, and the grip portion 6 is provided on the base end side. This shaft part 4
Is composed of a hollow cylindrical main body 4a having a true circular cross-section, and a rib 4b protruding from the inner surface of the main body 4a and extending in the longitudinal direction of the shaft 4.

In this embodiment, the ribs 4b are provided only on the side surface portion of the shaft portion located laterally in the front surface direction of the face portion 5 on the inner peripheral surface of the main body portion 4a. That is, the ribs 4b are provided only on the inner peripheral surface of the shaft portion where the surface including the face surface intersects the main body portion 4a and the vicinity thereof.

In this embodiment, three ribs 4b are provided on each of the left side surface and the right side surface of FIG. Each rib 4b is a tip 4f of the shaft portion 4.
To the rear end 4r.

The badminton racket having the shaft portion 4 thus constructed has a direction (second direction) along the face surface in a direction perpendicular to the face surface (directions C and C'in FIG. 2).
B) and B'direction). Moreover, the torsional rigidity of the shaft portion 4 is high. In addition, it is not necessary to increase the diameter of the shaft portion 4 in the racket width direction. Therefore, this badminton racket has a very good swing-out property.

In the present invention, the ribs may be provided only on a part of the shaft portion rather than the entire lengthwise direction. For example, like the shaft portion 7 in FIG. 6, ribs are provided separately in the range on the front end side and the range on the rear end side (that is, no rib is provided in the portion between and). Then, the bending rigidity of the portion becomes small. Therefore, the position of the kick point of the shaft portion of the badminton racket can be adjusted by adjusting the position of the portion where the rib is not provided.

The shaft portion of the badminton racket of the present invention is preferably made of fiber reinforced synthetic resin. To manufacture this fiber-reinforced synthetic resin shaft part, a mandrel in which a concave line corresponding to a rib is extended in the longitudinal direction,
A prepreg sheet in which carbon fiber, glass fiber, etc. are impregnated with a synthetic resin is wound, and the outer periphery thereof is wrapped with a special molding tape (for example, polypropylene tape). Next, the resin is heat-cured, the mandrel is pulled out, and the shaft portion made of the fiber-reinforced synthetic resin pipe is manufactured. The thin SMC material may be partially wound around the mandrel and then the prepreg sheet may be wound.

As a concrete manufacturing method, a synthetic resin is impregnated into reinforcing fibers, a unidirectionally aligned sheet and / or a woven fabric is wound around a mandrel, and then a resin impregnated roving of these fibers is applied to a shaft core. The fiber-reinforced synthetic resin pipe can be manufactured by winding the resin at an angle of 5 to 60 ° and curing by heating.

Further, a prepreg impregnated with a thermosetting resin is wound around a mandrel, a heat shrinkable tube is coated on the outer circumference of the wound sheet, and a tape is tightly wound around the outer circumference, and then the above impregnation is carried out by a conventional method. The fiber-reinforced synthetic resin pipe may be manufactured by subjecting the resin to a curing treatment in accordance with the conditions described above and molding by peeling off the tape and the heat-shrinkable tube in this order.

Further, a heat resistant film made of polyester, polypropylene or the like is attached to a prepreg in which reinforcing fibers are impregnated with a thermosetting resin such as phenol, epoxy, unsaturated polyester, etc. It is wound in a tubular shape so that the side is located on the inner surface, and the tubular body is inserted into an airtightly-maintaining tubular outer die whose inner surface in the axial direction is formed into a predetermined shape. Alternatively, a gas is injected to press the tubular body against the inner diameter surface of the outer die, and heat treatment is further applied to expand air or gas to tension the tubular body against the inner diameter surface of the outer die, followed by resin-cured tubular body. The fiber-reinforced synthetic resin pipe may be manufactured by pulling out from the outer mold. In this case, a smooth surface layer may be formed on the inner surface of the heat-resistant film with a release agent, and an outer mold having a smooth surface layer formed with a release agent on the inner diameter surface may be used. Is also good.

As the fiber-reinforced synthetic resin of the material forming the shaft portion, vinyl ester resin, polyester resin, unsaturated polyester resin and the like are used in addition to epoxy resin and phenol resin, among which epoxy resin and phenol resin are used. Resins are preferred and epoxy resins are particularly preferred.

Examples of the reinforcing fiber include carbon fiber, glass fiber, various ceramic fibers, metal fiber such as polon fiber, steel and stainless steel, organic fiber such as amorphous fiber and aromatic polyamide (for example, Kevlar fiber and Tyranno fiber). Mixed fabrics thereof are used, of which carbon fibers and glass fibers are preferable, and carbon fibers are particularly preferable.

When a phenol resin is used as the matrix resin, glass fiber is preferable.

The thickness of the reinforcing fiber is generally 3 to 13 μm.
Is preferable and 3-4 micrometers is especially preferable.

Generally, the proportion of reinforcing fibers in the prepreg sheet is preferably 60 to 75% by weight, and 67 to 72.
The weight% is particularly preferable, but in the sheet wound directly on the mandrel (or the sheet close to the mandrel), it is preferable to use a prepreg sheet having a large resin ratio (reinforcement fiber ratio of 50 to 60% by weight). By doing so, the resin easily enters the groove provided on the surface of the mandrel, and the rib can be formed with good moldability.

In order to make it easier for the reinforcing fibers to enter the groove,
The prepreg wound directly around the groove preferably has an orientation angle parallel to it.

The rib formed by such a manufacturing method is not attached to the inner surface of the shaft main body with an adhesive, but is integrally formed with the main body when the shaft is formed. Is extremely high.

In the shaft portion 4 made of this fiber reinforced synthetic resin pipe, the outer diameter (diameter) is 6 to 10 mm, the inner diameter (diameter) is 4.0 to 8.0 mm, and the thickness of the main body portion 4a (outer circumference). The difference between the radius of the surface and the radius of the inner peripheral surface is 1.5 to 2.5 m
It is preferably m. As for the ribs, the height (height in the radial direction) is 0.3 to 1.5 mm, the thickness (the thickness of the inner peripheral surface in the circumferential direction) is 0.5 to 2.5 mm, and the number (the inner peripheral The number of ribs in the circumferential direction of the surface) is preferably 2 to 10.

It is preferable that the ribs are arranged in a range in which the angle θ in FIG. 1 (d) is 30 ° to 90 °.

The shaft portion 4 may be straight, but it is preferable that the distal end side is thinner than the proximal end side, and the diameter on the distal end side is about 60 to 80% of the diameter on the proximal end side. Is preferred. Shaft length is 2
It is preferably about 50 to 350 mm.

[0035]

According to the badminton racket of the first and second aspects, the bending rigidity and the torsion rigidity of the shaft portion are high. Also,
It is also possible to adjust the kick point.

According to the badminton racket of the second aspect, the bending in the direction perpendicular to the face surface is good, the bending in the lateral direction of the racket along the face surface is small, and the swingability is very good.

[Brief description of drawings]

1A and 1B show a badminton racket according to an embodiment of the present invention, in which FIG. 1A is a front view, FIG. 1B is a sectional view taken along line BB of FIG. 1A, and FIG. (A) is a cross-sectional view taken along the line CC of FIG. 7 (d), and FIG.

FIG. 2 is a front view of a conventional badminton racket.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a shaft portion 1A of a conventional badminton racket.
FIG.

FIG. 5: Shaft portion 1B of a conventional badminton racket
FIG.

FIG. 6 is a front view of a badminton racket according to another embodiment.

[Explanation of symbols]

 1, 1A, 1B, 4, 7 Shaft part 2, 2A, 2B, 5 Face part 3, 6 Grip part 4a Main body part 4b Rib

Claims (2)

[Claims] 1. A badminton racket having a face portion, a hollow shaft portion, and a grip portion, wherein at least a part of an inner surface of the shaft portion is provided with a rib extending in a direction along an axis of the shaft portion. Badminton racket characterized by. 2. The badminton according to claim 1, wherein, of the inner surface of the shaft portion, the rib is provided only on a side surface portion of the shaft portion located laterally in a front direction of the face portion. racket.