JPH0442027B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is applicable to tennis, badminton, etc.
This invention relates to a racket that forms a net surface by stretching strings.

(Prior Art) As disclosed in Japanese Patent Laid-Open No. 56-8074, tennis rackets have traditionally been provided with a string holding part called a crown to tension the strings and form a string net surface. As in Publication No. 44-27260, protrusions for fixing the gutt are formed on the front and back surfaces of the frame, or as in Publication No. 52-76758, a protrusion is formed along the inner circumference of the frame, and the gutt is inserted into the protrusion. Some have a mesh surface formed by providing holes.

Also, rackets have been disclosed in which the net surface is made of a single surface, and in which two net surfaces are arranged parallel to each other with an interval in the ball hitting direction.

However, in commonly used racket frames made of fiber-reinforced resin (hereinafter abbreviated as FRP), the string mesh surface is a single surface, and the string insertion holes are perpendicular to the string mesh surface of the frame. A gutt insertion hole is formed by penetrating from the outer peripheral surface to the inner peripheral surface in the center of the thickness in the direction, that is, on the same plane as the gutt net surface, and the gutt is stretched in the insertion hole to form the gutt net. It formed a surface.

Furthermore, since the racket can be molded with fiber-reinforced resin, as disclosed in Japanese Utility Model Publication No. 58-46838, it is possible to widen the sweet spot by making the area of the string net wider than that of conventional regular size rackets. So-called large size rackets or semi-large size rackets are known.

(Problems to be Solved by the Invention) However, when strings are attached to these large size rackets and semi-large size rackets, the following problems occur.

In other words, large-sized and semi-large-sized rackets have larger frames than conventional regular-sized rackets, so they are more flexible, and if you tension them with the same tension as regular-sized rackets, they will not be tensioned. The ball was loose, which resulted in a high coefficient of restitution, which caused the ball to fly too far and become difficult to control.

In order to reduce the coefficient of restitution and improve ball control, the tension in the guts must be greater than when tensioning a regular-sized racket, but increasing the tension naturally reduces stress on the frame. It will become larger and require more force. Furthermore, the tension of the strings gradually decreases with repeated use of the racket, so the strings must be re-tensioned from time to time.
This also caused the FRP frame to easily cave in or break.

(Means for Solving the Problems) Therefore, in view of these conventional drawbacks, the present invention aims to reduce the tension of the strings of tennis rackets, especially large rackets and semi-large rackets, to the tension of the strings of conventional large rackets and semi-large rackets. Compared to the above, the mesh surface of the string has a tension that allows the desired coefficient of restitution to be obtained without making it too large, and furthermore, the loosening of the string that occurs due to repeated use is minimized, This was designed to provide a racket that can prevent the frame from collapsing or breaking. To explain the structure of the present invention based on drawings of a tennis racket, FIG. 1 shows the front of a racket 1 of the present invention, which is composed of a frame 2, a throat section, and a grip section, and the frame 2 has a string 6 attached to it. The mesh surface 3 is provided to form a mesh surface 3. FIG. 2 is an enlarged sectional explanatory view taken along the line A-A in FIG. It is an enlarged perspective view of a point. FIGS. 4 and 5 are explanatory views of other embodiments, and FIGS. 6 and 7 are explanatory views of conventional racket frames.

The feature of the present invention is that when forming the string net surface 3 on the frame 2 of the fiber-reinforced resin racket 1, the string insertion hole 4 for string tensioning has a thickness in the direction orthogonal to the string net surface 3 of the frame 2. From the outer peripheral surface side 5 central part to the inner peripheral surface side gutt mesh surface 3
This is a racket frame made of fiber-reinforced resin, characterized in that the holes are formed in a direction that is not on the same plane as the racket and is at an angle with the gutt mesh surface.

Therefore, as shown in FIGS. 2 and 3, there is a gap between the string mesh surface and the opening 4' of the string insertion hole 4.
It has a structure having a vertical distance D vertically with the string mesh surface as the center, and the strings 6a and 6b, which are stretched in the string insertion holes 4 and 6a, are stretched from the string insertion holes 4a and 6b, respectively, at right angles to the strings 6a and 6. It is bent and stretched with respect to the string 6A facing the string 6A, that is, the string surface 3.

When comparing the structure of a conventional racket and one embodiment of the present invention, the difference is clear. FIG. 6 shows a conventional racket 11, which consists of a frame 12, a throat section, and a grip section, and a gutted mesh surface 13 is formed on the frame. FIG. 7 shows a sectional view taken along the line CC in FIG. 6.

That is, in the conventional racket, the opening 14' of the string insertion hole 14 appearing on the inner circumferential surface side 13 of the frame is located at the center of the thickness in the direction perpendicular to the string surface of the frame. Therefore, if the strings 6 are stretched in these string insertion holes 14, at least the string surface 1 will be covered.
3 and the opening 14' are formed so as to be located substantially in the same plane.

On the other hand, according to the tensioning method shown in FIG. 2 which shows an example of the present invention, for example, the adjacent gutts 6a and 6b are
Each of the gutt insertion holes 4a, 4b is formed so as to have a vertical distance D from above and below, centering on the gutt mesh surface.

(Function) In the present invention, when drilling a string through hole for the purpose of forming the string mesh surface 3, the string insertion hole is formed from the center part on the outer peripheral surface side of the thickness of the frame to the string hole on the inner peripheral surface side. Since the gutt is drilled in a direction that is not on the same plane as the net surface and has an angle with the gutt net surface, if the gutt is stretched through the gutt insertion hole drilled in this way, The guts are stretched three-dimensionally as appropriate on the periphery of the inner circumferential surface of the frame, and as shown in FIG. Conversely, the gut 6b is pushed up at the contact B2 of the gut 6A.

That is, the point B1 that contacts the guts 6a and 6b,
Since they are stretched so that they are pulled in opposite directions using B2 as a fulcrum, it becomes like knitting the gutts, and the net surface of the gutts can be tightly connected with less tension than before, and the stretched gutts are Since they are intertwined with each other, they are difficult to loosen.

In addition, the stress applied to the frame when tensioning the strings is
Unlike the conventional case, the load is not applied directly to the gut insertion hole, but is distributed over the vertical distance D, thereby preventing the frame from collapsing or breaking.

(Other Embodiments) The gutt insertion holes of the present invention are bored on both sides of the widest vertical direction of the gutt net surface of the frame, on both sides of the horizontal direction, or in an arbitrary range on both sides of both directions. can be set.

At that time, as shown in FIGS. 4 and 5, a protrusion 8 is provided that extends in the direction of the center of the mesh surface in a direction horizontal to the mesh surface of the frame, and a hole is formed in the side surface 7 of the protrusion 8. It is also possible to drill a gut insertion hole so that the portion 4' is exposed. At this time, insert the insertion hole 4a downwardly at a position having a vertical distance D from the center of the outer circumferential surface of the frame in the direction perpendicular to the stringed mesh surface to the upper side of the stringed mesh surface on the inner peripheral surface side. If 4b is drilled at the same time at a position having a vertical distance D, when adjusting the gut,
The adjuster can arbitrarily select and adjust either of the insertion holes.

(Effects) When attaching strings to a large or semi-large size racket, the strings had to be pulled with much stronger force than conventional regular size rackets. According to the racket of the present invention, the string insertion hole 4 is arranged perpendicularly between the thickness of the frame 2 in the direction orthogonal to the string mesh surface 3 from the center part on the outer peripheral surface side to the string mesh surface on the inner peripheral surface side 7. Since the holes are drilled at a distance D, when strings are stretched, adjacent strings pull orthogonal strings in opposite directions, creating a so-called braided string shape. Therefore, the tension of the gut can be effectively utilized to form a tight mesh surface of the gut. Therefore, the distribution of the spring constant on the Guttu net surface can be made uniform, so that relatively uniform ball repulsion properties can be obtained over the entire Guttu net surface.

In addition, the frame of the ball hitting part has the largest deflection,
Therefore, by implementing the present invention in an arbitrary range centered on the widest part of the gutt net surface in the vertical and horizontal directions, where the tensile force of the guttation is least applied,
The stress applied to the frame when the strings are stretched is not directly applied in the direction parallel to the string surface of the frame, but is dispersed by the vertical distance D, reducing the stress burden on the frame and increasing its durability. In addition, since the gut is supported by the opening 4' on the inner circumferential surface side, vibration of the gut when a ball is hit can be suppressed, and abnormal sounds of the racket can be prevented.

Also, depending on the structure or design of the racket, the vertical distance D of the string insertion hole from the string surface
It can also be adjusted.

Furthermore, as shown in FIGS. 4 and 5, a protrusion 8 extending toward the center of the mesh surface is provided on the inner peripheral surface of the frame, and openings 4' are formed on both sides of the projection. If the gut insertion holes are drilled so that they appear at the same time at positions having a vertical distance D between the top and bottom from the center, no special reinforcement is required for the frame when drilling the holes, so manufacturing is easy, and the protrusion 8
By incorporating a weight for balance adjustment, the moment of inertia can be improved and the sweet spot can be expanded.

Thus, outside of tennis rackets, badminton,
It is advantageous to implement this method on skates, racquet balls, and other racquets that form a tight net surface.

[Brief explanation of drawings]

FIG. 1 is a front view showing an embodiment of a racket according to the present invention. FIG. 2 is an explanatory enlarged cross-sectional view taken along the line A-A in FIG. 1. FIG. 3 is an enlarged perspective view of point B in FIG. FIGS. 4 and 5 are enlarged perspective views of point B in another embodiment. FIG. 6 is a front view showing a conventional racket, and FIG. 7 is a sectional view taken along line C-C. 1, 11... Tennis racket, 2, 12... Frame, 3, 13... Gut mesh surface, 3'... Inner peripheral surface side, 4, 4a, 4b, 14... Gut insertion hole,
4', 14'...Opening part, 5...Outer peripheral surface side, 6, 6
a, 6b, 6A...gut, 7...side, 8...
Projection, 10...inner circumferential surface.

Claims (1)

[Claims] 1. In a fiber reinforced resin racket frame,
The string insertion hole for stringing the string is located at a position from the center of the outer peripheral surface of the frame in the direction orthogonal to the string mesh surface of the frame to a position that is not on the same plane as the string mesh surface on the inner peripheral surface. A racket made of fiber-reinforced resin characterized by being perforated in a direction that is at an angle to the net surface. 2 The gut insertion holes are located on both sides of the frame in the widest vertical direction, on both sides in the horizontal direction, or
2. The fiber reinforced resin racket according to claim 1, wherein the racket is provided with holes in arbitrary ranges on both sides in both directions.