JP2002126144A - Bat for baseball or softball - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bat more excellent in the resilience and durability than a conventional one whose hitting part is integrally formed from the top through the tapered part. SOLUTION: The hitting part 3 of the bat consists of a core material 3a, an elastic body 3b mounted around the core material 3a, and a hitting part pipe 3c set in the elastic body 3b. The elastic body 3b and the hitting part pipe 3c are separate from a top wall surface 6 and a tapered part wall surface 7 of the bat.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in rebound characteristics of a baseball or softball bat.

[0002]

2. Description of the Related Art Baseball or softball bats (hereinafter referred to as "bats") are made of wood, metal bats such as titanium, titanium alloys and aluminum alloys, as well as carbon fiber and glass fibers impregnated with a matrix resin. Bats made of various materials, such as fiber reinforced plastic bats, are supplied to the market.

Further, in the conventional bat, there is disclosed a bat in which various materials and structures are devised in order to improve the resilience and durability of the bat. For example, in Japanese Utility Model Publication No. 51-13265, a ball striking surface is formed by inserting a rubber or synthetic resin plate or a pipe into an intermediate layer of a double pipe, and has a strong repulsive force and excellent durability.
A metal baseball bat that absorbs vibration when hitting a ball is described.

In Japanese Utility Model Laid-Open No. 5-51377, a porous elastic cylinder is tightly fitted inside a hitting portion of a hollow bat body, and a carbon pipe is fitted and fixed on the inner side wall thereof to provide elasticity and durability. Are described.

Japanese Patent Application Laid-Open No. 2000-202080 describes an FRP bat which has a weak boundary layer (WBL) layer between layers of a fiber reinforced plastic material to improve rebound performance and satisfy durability. .

[0006]

As the thickness of the hitting portion of the bat becomes thinner, the deformation of the bat at the time of hitting becomes greater, and the restoring force when the hitting portion is restored from the deformed state to the original shape is obtained. This allows the ball to fly farther.
However, in the bat of Japanese Utility Model Publication No. 51-13265, the hitting portion has a three-layer structure, which has the effect of absorbing the vibration of the bat, but the flattening rigidity of the hitting portion increases, and the hitting portion deforms. It becomes difficult. Also, in the bat of Japanese Utility Model Laid-Open No. 5-51377, the hitting portion has a three-layer structure, the flat portion has a high flat rigidity, and the hitting portion is less likely to be deformed than a single hitting portion. JP 20
In the bat of No. 00-202080, the bat has a multilayer structure, and the outermost layer is made thin so that the outermost layer is not damaged even if the amount of deformation of the hitting portion is increased, but the hitting portion changes from the tip portion to the tapered portion. Since the ball is integrally formed over the entire surface, the deformation of the hitting ball cannot be so large.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a baseball or softball bat comprising a tip portion, a hitting portion, a tapered portion, and a grip portion. An elastic body provided around the core of the hitting portion, a hitting portion pipe fitted into the elastic body, and having an outer diameter of the hitting portion core at the boundary between the hitting portion and the tip portion and an outer diameter of the tip portion. By having a configuration in which the tapered portion wall surface between the outer diameter of the ball portion core material and the outer diameter of the tapered portion at the boundary between the tip portion wall surface and the hitting portion and the tapered portion, and the elastic body and the hitting portion pipe are separated, It is excellent in durability and can further improve the resilience characteristics compared to the conventional bat.

[0008]

FIG. 1 is a side sectional view of a baseball or softball bat embodying the present invention.
FIG. 2 is a sectional view taken along line AA of FIG. 1. The bat of the embodiment of FIG. 1 has a tip portion 2, a hitting portion core material 3 a, a tapered portion 4,
The grip portion 5 is formed of the same material, an elastic body 3b is provided around the hitting portion core material 3a, and a hitting portion pipe 3c is fitted on the elastic body 3b to form the hitting portion 3. Accordingly, the tip wall surface 6 between the outer diameter of the hitting portion core 3a and the outer diameter of the tip portion 2 at the boundary between the hitting portion 3 and the tip portion 2 and the hitting portion core at the boundary between the hitting portion 3 and the taper portion 4 The tapered portion wall surface 7 between the outer diameter of the tapered portion 3a and the outer diameter of the tapered portion 4 is separated from the elastic body 3b and the hitting portion pipe 3c. Note that the hitting portion core material 3a
Although the elastic body 3b and the elastic body 3b and the hitting portion pipe 3c may be separated from each other without being bonded, it is preferable to bond them using an adhesive or a double-sided tape.

[0009] By forming the hitting ball portion in this manner,
When the ball is hit, the elastic body is compressed, and the ball and the ball hitting portion move in the direction of the core of the hitting portion. After the elastic body is restored, the ball and the ball hitting portion move in the direction of the outer surface of the bat, and the ball is hit. It will be. In a conventional bat, the ball struck at the time of hitting is bent and the ball is greatly deformed, and the ball is launched while restoring the ball at the hitting surface. In the bat of the present invention, the ball and the ball hitting portion pipe are deformed after the elastic body is compressed without significantly deforming the ball at the time of hitting, and the deformation amount of the ball at the time of hitting is smaller than the conventional bat. In addition, energy loss due to deformation of the ball is reduced, and resilience characteristics are improved. In addition, by bonding the core of the hitting part and the elastic body, and the elastic body and the hitting part pipe, the elastic body and the hitting part pipe do not rotate at the time of hitting, and the collision energy at the time of hitting is efficiently converted to the compression energy of the elastic body. Can be converted.

The tip portion, the core portion of the hitting portion, the tapered portion, and the grip portion can be formed of wood, FRP, or metal. However, since the elastic member and the hitting portion pipe are attached to the hitting portion, It is desirable to have a structure in which the tip portion is attached to the hitting portion core material. In addition, the same material as a conventional wooden bat, an FRP bat, or a metal bat can be used for the wood, FRP, and metal.

The elastic body may be a material having a low energy loss rate when it is restored after elastic deformation. In addition to a material such as foamed polyurethane elastomer, EVA, ionomer, butadiene rubber, an air bag may be used. However, considering the weight and energy loss rate, the hardness is asker C type hardness tester (Japan Rubber Association Standard SRIS01).
Rubber sponge having a specific gravity of about 20 ° at a specific gravity of about 0.1 is preferable.

Next, results of two kinds of experiments performed to confirm the effect of the rubber sponge will be described. First, FIG. 3 shows a schematic view of an experimental apparatus used for a rebound test of a hit ball model. The experimental apparatus includes a pitching machine 10, a high-speed video camera 11, an image analyzer (not shown), only an iron plate as a collision object, an elastic plate attached to an iron plate, and an elastic member attached to an iron plate. An aluminum alloy plate was stuck on the body to form a hitting part model 12. In the experiment, a ball 13 launched from the pitching machine 10 was caused to collide with a fixed hitting part model 12, and this collision was detected from the side of the high-speed video camera 11 from the side.
, And the coefficient of restitution was calculated from the speed of the ball 13 before and after the collision.

The elastic body used in the ball hitting part model is a rubber sponge having a hardness of 20 degrees and a specific gravity of 0.07 as measured by an Asker C-type hardness meter, each having a square shape of 10 cm square and a thickness of 3 mm. An experiment was performed by attaching one to five rubber sponges. The aluminum alloy plate to be stuck on the rubber sponge is a square of 10 cm square and has a thickness of 2 cm.
mm.

This experiment was conducted using a rubber-ball baseball. This is because, when hitting a rubber ball of a softball or softball than a leather ball of a hardball or softball, the elastic deformation of the ball is greater and the rebound characteristics of the bat can not be fully utilized, There is a problem that there is no remarkable difference in repulsion characteristics even with a bat, and in order to confirm the configuration of a hitting portion that can increase the repulsion characteristics of a bat even with such a soft ball, a rubber ball is used. It is. Therefore, the resilience characteristics can be increased even in leather balls such as hardball and softball.

Next, the formula for calculating the coefficient of restitution e of the hitting part model and the description of the sign are shown in Expression 1, and the method of measuring the data is shown below.

E = V · BALL (OUT) / V · BALL (IN) (Equation 1) e: Coefficient of restitution V · BALL (IN): Center of gravity velocity of ball before collision (m
/ B) V · BALL (OUT): The velocity of the center of gravity of the ball after collision (m / s)

The velocity of the center of gravity of the ball in the above formula was obtained by performing image analysis on an image taken by a high-speed video camera with an image analyzer.

Tables 1 and 2 show the resilience test results of the hitting part model.
Shown in

[0019]

[Table 1]

[0020]

[Table 2]

As can be seen from the experimental results in Tables 1 and 2,
The higher the collision speed of the ball, the greater the deformation of the ball, and the lower the coefficient of restitution due to energy loss due to the deformation. On the other hand, as the number of rubber sponges increases,
The deformation of the ball is reduced, the energy loss is reduced, and the coefficient of restitution is increased. Further, the coefficient of restitution is slightly higher in the case where the aluminum alloy plate is stuck on the rubber sponge than in the case where only the rubber sponge is stuck.

Next, FIG. 4 shows a schematic view of an experimental apparatus used for the bat rebound test. The experimental apparatus was composed of a pitching machine 10, a high-speed video camera 11, an image analyzer (not shown), and a bat table 14. In the experiment, the ball 1 launched from the pitching machine 10
3 was caused to collide with a bat 15 placed on a bat placing table 14, and the resilience coefficient was calculated by an image analyzer.

The main specifications of the bat of the present invention and the conventional bat used in the above experiments are as shown in Table 3.

[Table 3]

Table 4 shows the results of an experiment in which a rubber ball was hit against the hitting portion of the bat at 130 km / h.

[Table 4]

As can be seen from the results in Table 4, the product of the present invention has a higher coefficient of restitution by about 5%. The relative speed between the ball and the bat at the time of the actual hit is about 200 k.
m / h, it is considered that the difference in the restitution coefficient between the conventional product and the invention product is further increased, and the difference in the flight distance is also increased.

From the above experimental results, it can be seen that the configuration in which a hard plate is stuck on a thick elastic body has the largest coefficient of restitution. Therefore, it is desirable that the hitting portion of the bat is configured such that an elastic body is provided around the hitting portion core material and the hitting portion pipe is fitted around the elastic body.

The hitting pipe is made of metal such as aluminum alloy or F
It is desirable to form with RP. The wall thickness of the hitting portion pipe varies depending on the type of bat, but in the case of a metal pipe, there is no problem in strength and durability as long as the thickness is equal to or slightly smaller than that of a current metal bat. In the case of the FRP pipe, various combinations can be used depending on the amount of the prepreg or the type and orientation angle of the prepreg to be used. Preferably, the prepreg is a combination of 9 to 10 carbon prepregs and glass prepregs, and has a thickness of 5.4 to 6 .0m
m is appropriate. However, even if the thickness is not increased, it is possible to increase the rigidity even with a thinner thickness than the current product by changing the type and orientation angle of the fiber used, and various specifications can be changed.

The bat can be formed integrally with a tip portion, a hitting portion core material, a tapered portion, and a grip portion.
From the standpoint of ease of manufacture, elasticity, and ease of mounting the hitting portion pipe, a structure in which the tip is attached to the hitting portion core material is desirable.
As shown in FIG. 5 (a), the tip mounting portion 3d may be protruded from the hitting portion core 3a, and the tip mounting portion 3d and the tip 2 may be screwed in. When the tip 2 is formed of a synthetic resin as shown in FIGS.
d may be protruded and attached so as to embed the tip attachment portion 3d.

The material of the tip portion may be the same material as the core material of the hitting portion, the tapered portion, and the grip portion, but may be formed of another material. Therefore, only the tip is made of metal and made heavy, or made of resin and made light,
You can also adjust the weight and balance of the bat.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a wooden soft bat according to the present invention will be described with reference to the drawings. In the bat of this embodiment, as shown in FIGS. 1 and 2, the distal end portion 2, the hitting portion core material 3 a, the tapered portion 4, and the grip portion 5 are formed by machining.
And the hitting portion core material 3a are joined by screwing as shown in FIG. 5 (a). The elastic body 3b and the hitting portion pipe 3c are attached to the hitting portion core material 3a having an outer diameter of 35 mm with a thickness of 15 mm.
A 2 mm thick aluminum alloy pipe is fitted into the rubber sponge. The hitting portion core 3a and the rubber sponge are adhered with a double-sided tape, and the rubber sponge and the aluminum alloy pipe are adhered with an adhesive.

The rubber sponge has a tensile strength of 0.38.
MPa, elongation 170%, tear strength 120N / cm
However, those having higher strength are preferable from the viewpoint of durability. Aluminum alloy pipe is AST
Although M-7000 series is used, a titanium alloy pipe may be used.

[0032]

According to the present invention, since the ball hitting portion is not formed integrally from the tip portion to the tapered portion unlike the conventional bat, the ball and the ball hitting portion pipe are not greatly deformed at the time of hitting, and the elastic body is formed. Is compressed and deformed, and the ball is launched by the restoration of the elastic body. Therefore, the energy loss due to deformation of the ball and the hitting part pipe is reduced,
The resilience characteristics are improved. Also, since the deformation of the hitting portion pipe is smaller than that of the conventional one, the durability is also excellent.

Further, since the ball hitting portion pipe separates from the tip portion and the tapered portion and the vibration is absorbed by the elastic body, the vibration of the hitting surface at the time of hitting is not transmitted to the grip portion, and the hand becomes numb at the time of hitting. There is no. Further, by increasing the contact time between the ball and the hitting portion pipe, the feeling that the ball is on the bat is obtained, and the shot feeling is improved.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a bat according to an embodiment.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a schematic diagram of a repulsion test apparatus for a hitting ball model.

FIG. 4 is a schematic diagram of a bat rebound test apparatus.

FIG. 5 is an explanatory view of how to attach a tip.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Baseball or softball bat 2 Tip part 3 Hitting part 3a Core part of hitting part 3b Elastic body 3c Hitting part pipe 3d Tip attaching part 4 Tapered part 5 Grip part 6 Tip part wall surface 7 Tapered part wall surface 10 Pitching machine 11 High Speed video camera 12 hitting part model 13 ball 14 bat table 15 bat

Claims (2)

[Claims] 1. A baseball or softball bat (1) comprising a tip portion (2), a hitting portion (3), a taper portion (4), and a grip portion (5), wherein the hitting portion (3) is a hitting portion. A core material (3a), an elastic body (3b) provided around the hitting part core material (3a), and a hitting part pipe (3) fitted on the elastic body (3b).
c), the tip end wall (6) and the hitting ball between the outer diameter of the hitting portion core (3a) and the outer diameter of the tip (2) at the boundary between the hitting portion (3) and the tip (2). A tapered wall surface (7) between the outer diameter of the hitting portion core (3a) and the outer diameter of the tapered portion (4) at the boundary between the portion (2) and the tapered portion (4), and the elastic body (3b) And a baseball or softball bat (1), wherein the hitting portion pipe (3c) is separated. 2. The baseball or softball bat (1) according to claim 1, wherein the elastic body (3b) provided around the hitting portion core (3a) is a rubber sponge.