Bat for baseball or softball, bat base material, and elastic body sleeve

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to improving the resilience characteristics of a baseball or softball bat.

【0002】

[Conventional technology]

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 fiber reinforced plastic fibers, glass fibers, etc. impregnated with matrix resin and cured. Bats made of various materials, such as plastic bats, are on the market.

【0003】

However, since it is difficult to significantly change the characteristic value of a bat with a bat composed of only the above materials, a bat combining various materials has been developed.

【0004】

Further, in order to greatly change the repulsive characteristic value of the bat, various types coated with an elastic body have been developed. For example, Japanese Patent Application Laid-Open No. 62-106784 discloses a cushion bat in which an elastic body is coated on a core portion over the entire length of the bat and the shape is the same as that of an existing bat. Japanese Patent Publication No. 63-156667 discloses a sponge rubber packing bat in which two sponge rubbers are bonded to a wooden core. Further, Japanese Patent Application Laid-Open No. 2000-153013 discloses a baseball bat in which an elastic body is coated on a peripheral surface excluding a grip portion of a core material of a lightweight metal pipe. Further, Japanese Patent No. 3003829 discloses a ball game bat in which a core material made of carbon fiber is coated with a hard urethane layer, and a protective layer made of glass fiber impregnated with a synthetic resin is provided on the hard urethane layer.

【0005】

[Problems to be Solved by the Invention]

In the bat disclosed in Japanese Patent Application Laid-Open No. 62-106784, Japanese Patent Application Laid-Open No. 63-156667, and Japanese Patent Application Laid-Open No. 2000-153013, the purpose of coating the elastic body is to reduce the impact and vibration at the time of striking. It is to obtain a bat that can be used safely by suppressing the flight distance of the hit ball. Therefore, elastic bodies are used that have physical characteristics that prevent the ball from flying, and these bats are suitable for use in narrow places, for hitting ping-pong balls, and for toss batting. In addition, Patent No. 3003829 aims to improve the manufacturing cost and manufacturing process, as well as the hitting sound and weight adjustment method, and the appearance and resilience performance are no different from those of the conventional bat.

【0006】

However, the characteristics required for bats used in baseball and softball are bats that are durable and fly well, and it has been difficult for the above-mentioned conventional bats to satisfy such requirements.

【0007】

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is a bat capable of extending the flight distance of a hit ball while exhibiting excellent durability, such a bat. It is to provide a bat base material and an elastic body sleeve which comprises.

【0008】

[Means for solving problems]

The inventor has completed the present invention as a result of various studies on the configuration of a bat capable of extending the flight distance of a hit ball. That is, it is effective to increase the repulsion characteristic value of the bat in order to extend the flight distance of the hit ball. Then, as a result of research, the inventor has found that it is effective to reduce the deformation of the ball at the time of hitting as a means for increasing the repulsion characteristic value.

【0009】

In order to reduce the deformation of the ball at the time of hitting the ball, it is conceivable to use a means such as covering the surface of the bat with an elastic body. However, bats used in baseball and softball games are not only durable and repulsive, but also mass and balance are important characteristics. If the elastic body is covered over the entire bat, the mass of the bat becomes large, and it becomes difficult to design these characteristics in a well-balanced manner.

【0010】

Based on the above-mentioned findings of the inventor, the baseball or softball bat according to the first aspect of the present invention is a baseball or softball bat composed of a tip portion, a hitting portion, a tapered portion, and a grip portion. In the above, the concave portion of the ball striking portion is coated and integrated with an elastic body having a physical property that increases the repulsion characteristic value.

【0011】

In this way, since the elastic body is compressionally deformed at the time of hitting the ball, the energy loss due to the deformation of the ball can be suppressed. Further, since the restoring force of the elastic body is applied to launch the ball, it is possible to obtain a well-flying bat having better repulsion characteristics than the conventional bat. That is, the deformation of the ball at the time of hitting can be reduced by the presence of the elastic body, and the restoring force of the elastic body can be utilized, so that the flight distance of the hit ball can be extended. In particular, even when hitting a soft ball such as a softball or a rubber softball, the resilience characteristic of the bat can be increased.

【0012】

Further, since the elastic body is coated only on a part of the bat called the concave portion of the ball striking portion, an increase in the mass of the bat can be suppressed as compared with the case where the elastic body is coated on the entire bat.

【0013】

Also, in a game, the bat is released when running after hitting a ball, but if the tip of the bat is covered with an elastic body, the tip may be damaged early due to friction with the ground. In the bat according to the present invention, there is no risk of the elastic body being covered only in the hitting portion (when the player releases the bat after hitting the ball, there is a risk that the ground and the elastic body come into contact with each other and the elastic body is damaged. Can be reduced).

【0014】

Further, in the bat according to the present invention, the tip portion, the hitting portion having a concave portion, the tapered portion, and the grip portion can be formed of a material having the same rigidity as the conventional bat, so that the bat has rigidity comparable to that of the conventional bat. Can be. Therefore, it can be a durable bat.

【0015】

Further, in the bat according to the present invention, since the vibration at the time of hitting the ball is absorbed by the elastic body, the batter's hand does not become numb at the time of hitting the ball. Further, since the elastic body is deformed at the time of hitting the ball, the contact time between the ball and the hitting portion is lengthened, so that the feeling that the ball is on the bat is obtained and the hitting feeling is improved.

【0016】

In the baseball or softball bat according to the above 1 aspect, the concave portion is provided in order to avoid damage due to stress concentration at the bottom corner of the concave portion and to avoid damage due to hitting the upper corner. , The boundary between the central part of the hitting part having an outer diameter smaller than the outer diameter of the hitting part, the tip side end to the tip part of the hitting part center part, and the taper part side end to the tapered part of the hitting part central part. It is desirable to increase the outer diameter up to.

【0017】

Further, in a baseball or softball bat according to the above aspect 1, the concave portion of the hitting portion has a central bottom whose distance from the central axis of the bat is smaller than the distance from the central axis to the outermost peripheral portion of the hitting portion. It is located at both ends of the wall and the central bottom wall in the direction along the central axis, the distance from the central axis is larger than the distance from the central axis to the central bottom wall, and from the central axis to the outermost part of the ball striking part. Further, it may include a stepped bottom wall extending in a direction substantially the same as the extending direction of the central axis, and a side wall connecting the central bottom wall and the stepped bottom wall. Further, the side wall may be inclined with respect to the central axis.

【0018】

Further, by forming the bottom wall of the stepped portion at the end portion of the concave portion, a convex portion is formed on the side wall of the concave portion. Therefore, the contact area between the wall surface of the recess and the elastic body can be increased. Therefore, even when hit by the end of the elastic body, there is no risk of peeling, and a bat having excellent durability can be obtained.

【0019】

In a baseball or softball bat according to the above aspect 1, the hitting portion is located in an area other than the concave portion, and is the outermost outer peripheral portion having the largest outer diameter and the wall surface of the concave portion, which is outside the outermost peripheral portion. A small outer diameter portion having an outer diameter smaller than the diameter and a wall surface of a recess extending in substantially the same direction as the extension direction of the central axis of a baseball or softball bat, which is located at the end of the recess and is small. It may include a middle outer diameter portion having an outer diameter larger than the outer diameter of the outer diameter portion and smaller than the outer diameter of the outermost outer diameter portion.

【0020】

In a baseball or softball bat according to the above aspect 1, the elastic body has a JIS C hardness of 20 to 80, a specific gravity of 0.25 to 0.70, and a tensile stress at 300% elongation of 1.0 MPa to 4.0 MPa. It is preferably a synthetic resin foam of. More preferably, the hardness of the elastic body is 20 to 50 in JISC hardness, the specific gravity is 0.25 to 0.50, and the tensile stress at 300% elongation is 1.0 MPa to 1.8 MPa. In this case, by using the so-called soft synthetic resin foam as described above, the repulsion characteristic value of the bat can be effectively increased.

【0021】

Further, in a baseball or softball bat according to the above aspect 1, it is desirable to use foamed polyurethane as the synthetic resin foam from the viewpoint of manufacturing cost and moldability. That is, if so-called soft polyurethane foam is used as the elastic body, the flight distance of the hit ball can be effectively extended and the increase in the manufacturing cost of the bat can be suppressed.

【0022】

Generally, polyurethane can be classified into three types, soft, semi-hard and hard, but the soft foamed polyurethane used as an elastic body in the present invention includes those classified into soft and semi-hard polyurethane. Hard polyurethane is not included. Here, the elongation of the hard polyurethane is generally several% to several tens of%, and the rigid polyurethane having an elongation of only this degree does not correspond to the foamed polyurethane as an elastic body in the present invention.

【0023】

The baseball or softball bat according to the above aspect 1 may include a protective film formed on the outermost layer of the elastic body.

【0024】

In this case, the protective film can suppress wear of the elastic body. Therefore, the durability of the bat can be improved. In particular, when a soft synthetic resin foam as described above is used as the elastic body, the durability of the bat can be effectively improved by forming the protective film.

【0025】

In a baseball or softball bat according to the above aspect 1, the protective film may include at least one of a synthetic resin sheet and a synthetic resin tube.

【0026】

In a baseball or softball bat according to the above aspect 1, the thickness of the protective film is preferably 0.1 mm or more and 1.0 mm or less, and the protective film preferably contains thermoplastic polyurethane.

【0027】

In this case, the workability in the work of forming the protective film and the adhesiveness between the elastic body and the protective film can be effectively improved.

【0028】

That is, in order to improve the durability of the bat, it is desirable to coat and mold the outermost layer of the synthetic resin foam with a synthetic resin sheet or tube having excellent wear resistance. Further, in consideration of workability and adhesiveness, it is desirable that the synthetic resin sheet or tube is a thermoplastic polyurethane sheet or tube having a thickness of 0.1 mm to 1.0 mm.

【0029】

In this case, the durability as a bat can be improved without impairing the characteristics of the elastic body enclosed inside the recess.

【0030】

Further, it is desirable that the thermoplastic polyurethane sheet or the thermoplastic polyurethane tube is transparent or translucent. By printing on one side of the sheet and fusing the sheet to the elastic body surface in a tube shape so that the printed side is on the inside, the printing can be seen through clearly and the appearance of the bat becomes beautiful. Furthermore, even if the bat is used for a long period of time, the print does not peel off.

【0031】

In a baseball or softball bat according to the above aspect 1, it is preferable that the recess is formed over the entire circumference of the hitting portion.

【0032】

In this case, the flight distance of the hit ball can be improved regardless of which part of the entire circumference of the hitting portion hits the ball.

【0033】

The bat base material according to another aspect of the present invention is a bat base material constituting a baseball or softball bat composed of a tip portion, a hitting portion, a tapered portion and a grip portion, and is a region to be a hitting portion. Is characterized in that a recess is formed in the.

【0034】

When such a bat base material is used, a bat according to the present invention can be easily manufactured by coating and integrating an elastic body in the recess.

【0035】

In the bat base material according to the other aspects described above, the region to be the hitting portion is located in the region other than the concave portion, and is the outermost outer peripheral portion having the largest outer diameter and the wall surface of the concave portion, which is outside the outermost peripheral portion. A small outer diameter portion having an outer diameter smaller than the diameter and a wall surface of a recess extending in substantially the same direction as the extension direction of the central axis of the bat, located at the end of the recess, and the outer diameter of the small outer diameter portion. It may include a middle outer diameter portion having an outer diameter larger and smaller than the outer diameter of the outermost outer diameter portion.

【0036】

In this case, since a thin region can be formed at the end of the elastic body covered with the concave portion, a bat in which the elastic body is hard to be peeled off from the bat base material can be easily formed.

【0037】

An elastic body sleeve according to another aspect of the present invention constitutes a baseball or softball bat composed of a tip portion, a hitting portion, a tapered portion and a grip portion, and is an elastic body fitted in a recess formed in the hitting portion. A sleeve that is located in the center of the elastic sleeve and has the smallest inner diameter and the end of the elastic sleeve, and has an inner diameter larger than the inner diameter of the minimum inner diameter. It is provided with an inner diameter expanding portion extending in substantially the same direction as the extending direction.

【0038】

By using such an elastic sleeve, the bat according to the present invention can be easily manufactured by covering and integrating the elastic sleeve in the recess of the ball striking portion.

【0039】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings below, the same or corresponding parts will be given the same reference number and the explanation will not be repeated.

【0040】

(Embodiment 1) FIG. 1 is a schematic side sectional view showing the first embodiment of the bat according to the present invention. FIG. 2 is a schematic cross-sectional view of the line segment II-II of FIG. Embodiment 1 of the bat according to the present invention will be described with reference to FIGS. 1 and 2.

【0041】

The bat of the present invention is an elastic body having the largest resilience characteristic confirmed by various experiments, which is coated and integrated in a concave portion of a ball striking portion. As shown in FIGS. 1 and 2, the baseball or softball bat 1 includes a tip portion 10, a ball striking portion 11, a taper portion 12, and a grip portion 13. The bat base member 7 as a bat base material constituting the bat 1 has a recess 2 formed in a portion to be a hitting portion 11. The recess is formed from the point of view of the durability of the bat to the boundary between the central portion 11a of the hitting portion having an outer diameter smaller than the outer diameter of the hitting portion 11 and the tip side end 11b of the central portion 11a of the hitting portion to the tip portion 10. It is desirable to increase the outer diameter from the tapered portion side end 11c of the ball striking portion central portion 11a to the boundary with the tapered portion 12. An elastic body 3 is coated and integrated in the recess 2 formed over the entire circumference of the ball striking portion 11. The recess 2 may be formed in a part of the ball striking portion 11 in the circumferential direction. Further, at the terminal portion of the grip portion 13, the grip end 4 is fitted and fixed to the butt base member 7.

【0042】

In such a bat 1 according to the present invention, since the elastic body 3 is compressively deformed at the time of hitting a ball, the energy loss due to the deformation of the ball can be suppressed. Further, since the restoring force of the elastic body 3 is added to launch the ball, it is possible to obtain a well-flying bat 1 having better repulsion characteristics than the conventional bat. In particular, even when hitting a soft ball such as a softball or a rubber softball, the repulsive characteristic of the bat 1 can be increased.

【0043】

Further, since the elastic body 3 is covered only with a part of the bat 1 called the recess 2 of the ball striking portion 11, the increase in the mass of the bat 1 can be suppressed as compared with the case where the elastic body 3 is covered with the entire bat 1.

【0044】

Also, in the game, the bat 1 is released when running after hitting the ball, but if the tip 10 of the bat is covered with an elastic body, the elastic body may be damaged early due to friction with the ground. There is. In the bat 1 according to the present invention, since the elastic body 3 is coated only on the hitting portion 11, there is no fear of it.

【0045】

Further, in the bat 1 according to the present invention, the ball striking portion 11 having the tip portion 10, the concave portion 2, the tapered portion 12, and the grip portion 13 can be formed of a material having the same rigidity as that of the conventional bat as described later. It can be made to have rigidity comparable to that of the bat. Therefore, a durable bat 1 can be obtained.

【0046】

Further, in the bat 1 according to the present invention, since the vibration at the time of hitting the ball is absorbed by the elastic body 3, the batter's hand does not become numb at the time of hitting the ball. Further, since the elastic body 3 is deformed at the time of hitting the ball, the contact time between the ball and the hitting portion 11 becomes longer, so that the feeling that the ball is on the bat 1 can be obtained, and the hitting feeling is improved.

【0047】

Further, since the recess 2 is formed over the entire circumference of the hitting portion 11, the flight distance of the ball can be extended regardless of which portion of the hitting portion 11 hits the ball.

【0048】

As shown in FIG. 3, the bottom corner 2a and the top corner 2b of the recess 2 are rounded, and the side wall 2c of the recess 2 is perpendicular to the central axis 6 (see FIG. 1) in the length direction of the bat. It can also be formed. FIG. 3 is a schematic partial cross-sectional view for explaining the first modification of the first embodiment of the bat according to the present invention shown in FIGS. 1 and 2.

【0049】

The entire bat (bat base member 7) having the recess 2 formed in the ball striking portion 11 can be formed of any of wood, metal, and fiber reinforced plastic using a conventional material. The tip portion 10 and the grip end 4 may be formed integrally with the bat base member 7 as the entire bat, but may be formed and attached separately.

【0050】

It is desirable that the elastic body 3 is coated and integrated with the recess 2 of the ball striking portion 11 by injection molding or casting molding of a synthetic resin. The elastic body 3 as the elastic body sleeve may be formed as a separate body so as to match the shape of the concave portion 2 of the ball striking portion 11 and may be adhered.

【0051】

The elastic body 3 may be made of a material having a low energy loss rate when restored after elastic deformation, and a material such as ionomer or butadiene rubber or an air bag can be used, but the mass and energy loss can be used. Considering the rate, manufacturing cost and ease of molding, foamed polyurethane with a hardness of 20 to 80 for JIS C hardness, a specific gravity of 0.25 to 0.70, and a tensile stress of 1.0 MPa to 4.0 MPa at 300% elongation is preferable. .. The above numerical range was determined for the following reasons. That is, when the hardness is 20 or less, molding as a bat becomes difficult, and when the hardness is 80 or more, the repulsion characteristics are not so different from those of the conventional bat. Similarly, when the specific gravity is 0.25 or less, molding as a bat becomes difficult, and when it is 0.70 or more, the repulsion characteristics are not so different from those of the conventional bat. Further, when the tensile stress at 300% elongation is 1.0 MPa or less, molding as a bat becomes difficult, and when it is 4.0 MPa or more, the repulsion characteristics are not so different from those of the conventional bat.

【0052】

When emphasizing repulsion characteristics, use polyurethane foam with a hardness of 20 to 50 for JIS C hardness, a specific gravity of 0.25 to 0.50, and a tensile stress of 1.0 MPa to 1.8 MPa at 300% elongation as the elastic body 3. Is preferable.

【0053】

FIG. 4 is a schematic side sectional view for explaining a second modification of the first embodiment of the bat according to the present invention. Figure 4 corresponds to Figure 1. A second modification of the bat will be described with reference to FIG.

【0054】

As shown in FIG. 4, the bat 1 basically has the same structure as the bat 1 shown in FIGS. 1 and 2, but a sheet 5 as a protective film is formed on the surface of the elastic body 3.

【0055】

In this way, since the elastic body 3 is protected by the sheet 5, the durability of the bat 1 can be improved. In particular, when a synthetic resin foam is used as the elastic body 3, the durability of the bat can be effectively improved by arranging such a sheet 5.

【0056】

As the sheet 5 coated and molded on the outermost layer of the elastic body 3 made of the synthetic resin foam or the like, it is desirable to use a synthetic resin sheet or tube having excellent wear resistance. Considering workability and adhesiveness, it is desirable that the synthetic resin sheet or tube is a thermoplastic polyurethane sheet or tube having a thickness of 0.1 mm or more and 1.0 mm or less.

【0057】

Here, if the thickness of the synthetic resin sheet or tube is less than 0.1 mm, the strength of the sheet or tube itself is insufficient, and it does not become a factor for increasing the durability. Further, if it exceeds 1.0 mm, the sheet 5 itself becomes hard, and there is a drawback that the characteristics of the elastic body 3 enclosed inside are impaired. In addition, the above thermoplastic polyurethane sheet or tube has JIS A hardness of 80 to 100 and tensile strength of 450 to 500 kg / cm.²It is desirable to use one. If the JIS A hardness is less than 80, the strength of the sheet or tube itself will be insufficient, and it will not be a factor to improve durability. Further, when the JIS A hardness exceeds 100, the sheet 5 itself becomes hard, and there is a drawback that the characteristics of the elastic body 3 enclosed inside are impaired. The same can be said about the tensile strength.

【0058】

Further, it is desirable that the synthetic resin sheet used as the sheet 5 is transparent or translucent, so that one side of the sheet 5 is printed, and the sheet 5 is fused in a tube shape so that the printed side is on the inside. Furthermore, by molding the above tube integrally with the elastic body 3, the print can be seen through clearly and the appearance becomes beautiful, and even if the bat 1 is used for a long period of time, the print does not peel off. Is possible.

【0059】

(Embodiment 2) FIG. 5 is a schematic side sectional view showing the second embodiment of the bat according to the present invention. FIG. 6 is a schematic cross-sectional view of the line segment VI-VI of FIG. FIG. 7 is a schematic partial cross-sectional view for explaining the recess of the bat shown in FIG. A second embodiment of the bat according to the present invention will be described with reference to FIGS. 5 to 7.

【0060】

As shown in FIGS. 5 to 7, the bat 1 basically has the same structure as the bat shown in FIG. 4, but the shape of the recess 2 is different. That is, the recess 2 has a ball hitting portion central portion 11a in which the distance from the central axis 6 of the baseball or soft ball bat 1 is smaller than the distance R1 (see FIG. 7) from the central axis 6 to the outermost peripheral portion of the hitting section 11. It is located at both ends of the central part bottom wall 8 as a small outer diameter part of the ball and the central part 11a of the ball striking part in the direction along the central axis 6, and the distance from the central axis 6 is from the central axis 6 to the central part 11a of the ball striking part. The distance to the bottom wall 8 at the center of the ball is larger than R2 (see FIG. 7), and the distance from the central axis 6 to the outermost peripheral portion 9 of the ball striking portion 11 is less than R1. Includes an end region 15 (see FIG. 5) as the bottom wall of the step portion extending to, and a side wall 26 connecting the central portion 11a of the ball striking portion and the end region 15 as the middle and outer diameter portions. Further, the side wall 26 is inclined with respect to the central axis 6.

【0061】

In this case, the thickness of the inner diameter enlarged portion 17 (see FIG. 5), which is the end of the elastic body 3 (see FIG. 5) as the elastic sleeve located on the end region 15, is the center of the elastic body 3. It is relatively thinner than the minimum inner diameter portion 16 (see FIG. 5), which is a portion (the elastic body 3 is located at the minimum inner diameter portion 16 having the smallest inner diameter and the end portion of the elastic body 3, and the inner diameter of the minimum inner diameter portion 16 It has a larger inner diameter and includes an inner diameter expanding portion 17 extending in substantially the same direction as the extending direction of the elastic body 3 (extending direction of the central axis 6).

【0062】

Further, by forming the end region 15 at the end of the concave portion 2, a convex portion (stepped portion 14 (see FIG. 7)) is formed on the side surface of the concave portion 2. Therefore, the contact area between the side surface of the recess 2 and the elastic body 3 can be increased. Therefore, even when the ball is hit by the end portion of the elastic body 3, there is no possibility that the elastic body 3 is peeled off, and the bat 1 having excellent durability can be obtained.

【0063】

The shape of the recess 2 of the bat 1 can be specifically as follows. For example, as shown in FIG. 7, the distance R1 from the central axis 6 of the bat 1 to the outermost circumference of the hitting portion 11 (see FIG. 5) is 34.5 mm, and the distance R2 from the central axis 6 to the hitting portion central portion 11a is 20 mm. Consider the case. In this case, the distance T, which is the depth from the outermost peripheral surface of the ball striking portion 1 (see FIG. 5) to the surface of the end region 15, can be 1.0 mm or more and 10.0 mm or less. Further, it is preferable that the distance T is 1.5 mm or more and 7.0 mm or less. Further, it is more preferable that the distance T is 2.0 mm or more and 4.0 mm or less. Here, if the distance T is less than 1.0 mm, the thickness of the elastic body 3 (see FIG. 5) arranged on the end region 15 becomes too thin, so that the elastic body 3 is easily peeled off or the elastic body 3 is easily peeled off. There is a problem that it is easy to cut. If the distance T exceeds 10.0 mm, there is a risk that the strength of the bat base member 7, which is the main body of the bat 1 (see FIG. 5), will be problematic (sufficient strength cannot be obtained).

【0064】

Further, the width L of the end region 15 may be 3.0 mm or more and 30.0 mm or less. Further, it is preferable that the width L is 5.0 mm or more and 25.0 mm or less. Further, it is more preferable that the width L is 10.0 mm or more and 20.0 mm or less. Here, if the width L is less than 3.0 mm, the contact area between the elastic body 3 (see FIG. 5) and the end region 15 becomes small, so that the elastic body 3 easily peels off from the end region 15. Further, when the width L exceeds 30.0 mm, the size of the portion where the elastic body 3 having a sufficient thickness is arranged in the ball striking portion 11 (see FIG. 5) becomes small. That is, the portion where the flight distance of the hit ball can be increased most becomes smaller.

【0065】

Further, the inclination angle of the surface of the end region 15 with respect to the central axis 6 of the bat 1 (see FIG. 5) can be -18 ° or more and + 18 ° or less. Here, the inclination angle of -18 ° means that the tip portion 10 (see FIG. 5) side of the butt 1 of the end region 15 is tilted toward the central axis 6 side, and the surface of the end region 15 in FIG. Assuming a straight line along, it means that the intersection angle between the straight line and the central axis 6 is 18 °. Further, the inclination angle of + 18 ° means that the grip portion 13 (see FIG. 5) side of the bat 1 of the end region 15 is tilted toward the central axis 6 side, and is on the surface of the end region 15 in FIG. Assuming a straight line along, it means that the intersection angle between the straight line and the central axis 6 is 18 °. Further, the inclination angle is preferably -12 ° or more and + 12 ° or less, and more preferably -6 ° or more and + 6 ° or less.

【0066】

Here, when the inclination angle of the end region 15 is less than -18 ° or more than + 18 °, the elastic body 3 and the butt base member 7 (see FIG. 5) are likely to be separated from each other.

【0067】

Further, as shown in FIG. 7, the side wall 26 connecting the end region 15 and the central bottom wall 8 of the ball striking portion central portion 11a (central portion of the recess 2) is inclined with respect to the central axis 6. It may extend substantially perpendicular to the central axis 6.

【0068】

FIG. 8 is a schematic side sectional view showing a modified example of the second embodiment of the bat according to the present invention. FIG. 8 corresponds to FIG. A modified example of the second embodiment of the bat according to the present invention will be described with reference to FIG.

【0069】

As shown in FIG. 8, the bat 1 basically has the same structure as the bats shown in FIGS. 5 to 7, but a sheet 5 (see FIG. 5) is formed on the surface of the elastic body 3 of the ball striking portion 11. Not. That is, the surface of the elastic body 3 is exposed. In this case as well, the same effect as that of the bat shown in FIGS. 5 to 7 can be obtained.

【0070】

Next, the results of two types of experiments conducted to confirm the effect of polyurethane foam used as the material of elastic body 3 (see Fig. 1) are shown.

【0071】

First, a repulsion experiment of the hitting part model was carried out using the experimental device as shown in FIG. FIG. 9 is a schematic schematic diagram of the experimental device used for the repulsion experiment of the ball striking part model.

【0072】

As shown in FIG. 9, the experimental apparatus includes a pitching machine 20, a high-speed video camera 21, and an image analyzer (not shown). As the ball striking part model 22 which is a collision symmetric object that causes the ball 23 to collide, only an iron plate and one in which an elastic body is attached to the iron plate are prepared. In the experiment, the ball 23 launched from the pitching machine 20 was made to collide with the fixed ball striking part model 22. Then, this collision was photographed from the side by a high-speed video camera 21, and the coefficient of restitution was calculated from the speed of the ball 23 before and after the collision.

【0073】

The elastic body used for the ball striking part model is a foamed polyurethane sheet with JIS C hardness of 40 to 80 and specific gravity of 0.35 to 0.66, which is a square with a side of 10 cm and a thickness of 10 mm.

【0074】

This experiment was conducted using a softball baseball. This is a problem that when a rubber ball is hit in a softball or softball, the elastic deformation of the ball is large, the repulsive characteristics of the bat cannot be fully utilized, and there is no significant difference in the repulsive characteristics of any bat. In order to confirm the configuration of the hitting portion that can increase the repulsive characteristic of the bat even in such a soft ball, a softball baseball is used. Therefore, similar effects can be obtained with varying degrees of hardball baseball and leather softball.

【0075】

Next, the calculation formula of the coefficient of restitution e and the explanation of the code are shown in Equation 1, and the data measurement method is shown below.

【0076】

[Number 1]

<img file="JP2003019236A_D0001.tif" />【0077】

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

【0078】

Next, Table 1 shows the results of a repulsion experiment in which a softball baseball ball collided with each hitting part model at a speed of 30 m / s.

【0079】

[table 1]

<img file="JP2003019236A_D0002.tif" />【0080】

As can be seen from the experimental results in Table 1, the coefficient of restitution is higher when the elastic body is attached than when it is made to collide with an iron plate having a flat surface. Further, the lower the hardness of the elastic body, the smaller the specific gravity of the elastic body, and the smaller the elastic modulus of the elastic body, the higher the coefficient of restitution.

【0081】

Next, a repulsion experiment of the bat was performed using the experimental device as shown in FIG. FIG. 10 is a schematic schematic diagram of the experimental device used for the repulsion experiment of the bat.

【0082】

As shown in FIG. 10, the experimental apparatus consisted of a pitching machine 20, a high-speed video camera 21, an image analyzer (not shown), and a bat stand 24.

【0083】

In the experiment, the ball 23 launched from the pitching machine 20 collided with the bat 25 placed on the bat stand 24. Then, this collision was photographed from directly above by a high-speed video camera 21, and the coefficient of restitution was calculated from the speed of the ball 23 before the collision, the speed of the ball 23 after the collision, and the speed of the bat 25. The coefficient of restitution e was calculated by Equation 2.

【0084】

[Number 2]

<img file="JP2003019236A_D0003.tif" />【0085】

Using the experimental device shown in FIG. 10, the coefficient of restitution was determined for the bat according to the present invention shown in FIGS. 1 and 2. The bats used in the repulsion experiment were the conventional metal softball bat and the fiber reinforced plastic softball bat shown in FIGS. 1 and 2 according to the present invention. The main specifications are shown in Table 2. As shown. The elastic body of the bat of the present invention is polyurethane foam with JIS C hardness of 43, specific gravity of 0.35, elastic modulus (tensile stress at 300% elongation) of 1.23 MPa, and a thickness of 20 mm in the recess of the ball striking part. The coating is integrated.

【0086】

[Table 2]

<img file="JP2003019236A_D0004.tif" />【0087】

Table 3 shows the results of an experiment in which a softball baseball ball was made to collide with the hitting part of the bat at 130 km / h.

【0088】

[Table 3]

<img file="JP2003019236A_D0005.tif" />【0089】

As can be seen from the results in Table 3, the product of the present invention has a higher coefficient of restitution of about 10%, and it can be said that the product of the present invention flies better than the conventional product.

【0090】

In addition, the coefficient of restitution was determined for the bat according to the present invention shown in FIGS. 5 and 6 using the experimental device shown in FIG. The bats used in the repulsion experiment were the conventional metal softball bat and the fiber reinforced plastic softball bat shown in FIGS. 5 and 6 according to the present invention. The main specifications are shown in Table 4. As shown.

【0091】

Further, the distance T, which is the depth of the end region 15 in the recess 2 (see FIG. 5) of the bat according to the present invention used in the experiment, is 4.0 mm, the width L of the end region 15 is 15.0 mm, and the bat 1 (see FIG. 5). The inclination angle of the surface of the end region 15 with respect to the central axis 6 (see FIG. 7) was set to 0 ° (the surface of the end region 15 is substantially parallel to the central axis 6).

【0092】

The elastic body of the bat according to the present invention is polyurethane foam having a JIS C hardness of 43, a specific gravity of 0.35, and an elastic modulus (tensile stress at 300% elongation) of 1.23 MPa, and is thick at the center of the recess of the ball striking part. The coating is integrated at a hardness of 20 mm. Furthermore, the outermost layer of polyurethane foam as elastic body 3 (see Fig. 5) has a JISA hardness of 91 and a tensile strength of 474 kg / cm.²A thermoplastic polyurethane tube as a sheet 5 (see FIG. 5) having a thickness of 0.3 mm obtained by fusing the sheets of the above is integrally molded with the elastic body.

【0093】

[Table 4]

<img file="JP2003019236A_D0006.tif" />【0094】

Table 5 shows the results of an experiment in which a softball baseball ball was made to collide with the hitting portion of the bat at 130 km / h in the same manner as in the case of the bats shown in FIGS. 1 and 2 of the present invention.

【0095】

[Table 5]

<img file="JP2003019236A_D0007.tif" />【0096】

As can be seen from the results in Table 5, the coefficient of restitution of the product of the present invention is about 7% higher, and it can be said that the product of the present invention flies better than the conventional product.

【0097】

As described above, the bats according to the present invention shown in FIGS. 1 and 2 or 5 and 6 all have a higher coefficient of restitution than the conventional products. This is considered to be due to the following reasons. That is, in the conventional bat, the hitting surface bends at the time of hitting and the ball is greatly deformed, and the hitting surface and the ball are restored while the ball is launched. On the other hand, in the bat of the present invention, the impact energy at the time of hitting a ball is first converted into compression energy by compressing a thermoplastic polyurethane tube having a thickness of 0.3 mm and an elastic body (or elastic body 3 (see FIG. 1)). To. After that, since the ball is compressed and deformed, the amount of deformation of the ball at the time of hitting is smaller than that of a conventional bat. As a result, it is considered that the energy loss due to the deformation of the ball is reduced, the restoring force of the elastic body is added, and the repulsion characteristic is improved.

【0098】

Further, it goes without saying that the thermoplastic polyurethane tube integrally molded with the outermost layer of the elastic body functions without impairing the characteristics of the elastic body enclosed inside, and is excellent in durability.

【0099】

[Example]

Hereinafter, examples of the Japanese-style baseball bat of the present invention will be described with reference to the drawings.

【0100】

(Example 1) In order to confirm the effect of the bat according to the present invention shown in FIGS. 1 and 2, an actual striking test was conducted.

【0101】

The softball bat 1 which is an example of the bat according to the present invention shown in FIGS. 1 and 2 used in the test is a hollow bat made of fiber reinforced plastic, and has a tip portion 10, a ball striking portion 11 having a recess 2, and a tapered portion. 12. The outer shell (butt base member 7) of the grip portion 13 is formed by an internal pressure molding method, and the grip end 4 separately molded with synthetic resin is inserted and bonded to the end of the grip portion 13. Then, after the concave portion 2 of the ball striking portion 11 is sandblasted, the concave portion 2 is cast-molded using a mold designed so that the elastic body 3 can be coated and integrated with the concave portion 2. The elastic body 3 was made of foamed polyurethane having a JIS C hardness of 43, a specific gravity of 0.35, and an elastic modulus (tensile stress at 300% elongation) of 1.23 MPa.

【0102】

The outer diameter of the hitting portion 11 is 70 mm, and the outer diameter of the hitting portion central portion 11a from the position 40 mm from the tip of the bat to 260 mm is 30 mm. Then, the outer diameter from the tip side end 11b of the hitting portion central portion 11a to the boundary with the tip portion 10 and the outer diameter from the tapered portion side end 11c of the hitting portion central portion 11a to the boundary with the tapered portion 12 are increased. It is formed by letting it.

【0103】

An actual hit test was conducted using the above-mentioned softball baseball bat 1 according to the present invention and a conventional metal softball baseball bat. The results are shown in Table 6.

【0104】

[Table 6]

<img file="JP2003019236A_D0008.tif" />【0105】

The result of the above-mentioned actual hitting test is an average value of five amateur baseball members, but the result predicted from the result of the repulsion experiment, that is, the bat according to the present invention has a longer flight distance than the conventional product. Was confirmed.

【0106】

(Example 2) Next, in order to confirm the effect of the bat according to the present invention shown in FIGS. 5 and 6, an actual striking test similar to the experiment in Example 1 was performed.

【0107】

The softball bat 1 shown in FIGS. 5 and 6 is a hollow bat made of fiber reinforced plastic having basically the same structure as the bat of the first embodiment, and has a tip portion 10, a ball striking portion 11 having a recess 2, and a taper. The outer shells of the portion 12 and the grip portion 13 are formed by an internal pressure molding method, and the grip end 4 separately molded with synthetic resin is inserted and bonded to the end of the grip portion 13. As shown in FIG. 5, an end region 15 is formed at the end of the recess 2 formed in the ball striking portion 11. Then, after sandblasting the recess 2 of the ball striking portion 11, a tube as a sheet 5 obtained by fusing an elastic body 3 to the recess 2 and a thermoplastic polyurethane sheet having a thickness of 0.3 mm to the outermost layer is formed. It is cast-molded using a mold designed so that the coating can be integrated. As the elastic body 3, polyurethane foam having a JIS C hardness of 43, a specific gravity of 0.35, and an elastic modulus (tensile stress at 300% elongation) of 1.23 MPa was used as in the bat of Example 1. As the sheet 5 formed on the surface of the elastic body 3, a tube obtained by fusing a 0.3 mm thermoplastic polyurethane sheet was used. This tube is JIS A hardness is 91, tensile strength is 474 kg / cm²Met.

【0108】

The outer diameter of the hitting portion 11 is 70 mm, and the outer diameter of the hitting portion central portion 11a from the position 40 mm from the tip of the bat to 260 mm is 30 mm. Then, as shown in FIG. 7, the side wall 26 connecting the end regions 15 located at both ends of the recess 2 and the bottom wall of the central portion of the recess 2 is provided with respect to the central axis 6 of the bat 1 (see FIG. 5). (As shown in FIG. 5, the outer diameter from the tip side end 11b of the hitting portion central portion 11a to the boundary with the end region 15 located on the tip portion 10 side and the hitting portion central portion 11a. The outer diameter from the tapered end 11c to the boundary with the end region 15 located on the tapered 12 side is increased).

【0109】

An actual hit test was conducted using the softball bat 1 of the above embodiment and a conventional metal softball bat. The results are shown in Table 7.

【0110】

[Table 7]

<img file="JP2003019236A_D0009.tif" />【0111】

The result of the above-mentioned actual hitting test is an average value of five amateur baseball members, but as predicted from the result of the repulsion experiment, the bat according to the present invention has a longer hitting distance than the conventional product. Was confirmed.

【0112】

[Effect of the invention]

As described above, in the present invention, the elastic body is compressionally deformed at the time of hitting the ball, the energy loss due to the deformation of the ball is suppressed, and the restoring force of the elastic body is added to launch the ball. It can be a well-flying bat with excellent resilience characteristics.

【0113】

In particular, even when hitting a soft ball such as a softball or a rubber softball, the resilience characteristic of the bat can be increased.

【0114】

Furthermore, by coating the outermost layer of the elastic body with a thermoplastic polyurethane sheet or tube with a thickness of 0.1 mm to 1.0 mm, which has excellent wear resistance, it can be used as a bat without impairing the characteristics of the elastic body enclosed inside. Durability can be improved. Further, the elastic body and the thermoplastic polyurethane sheet do not peel off even at the end due to the step portion (end region) provided near the tip portion and the step portion (end region) provided near the taper portion. It has excellent durability.

【0115】

It is desirable that the thermoplastic polyurethane sheet is transparent or translucent, and by printing on one side of the sheet and fusing the sheet in a tube shape so that the printed side is on the inside, the printing can be clearly seen through. It looks and looks beautiful, and even if the bat is used for a long period of time, the print does not peel off.

【0116】

In the game, the bat is released when running after hitting the ball, but if the tip of the bat is covered with an elastic body, the tip may be damaged early due to friction with the ground. In the bat of the present invention, since the elastic body is coated only on the hitting portion, there is no fear of it.

【0117】

Further, in the bat of the present invention, the tip portion, the ball striking portion having a concave portion, the tapered portion, and the grip portion are formed of the same rigid material as the conventional bat, so that the rigidity is comparable to that of the conventional bat. It has and can be a durable bat.

【0118】

Further, in the bat of the present invention, since the vibration at the time of hitting the ball is absorbed by the elastic body, the hand does not become numb at the time of hitting the ball. Further, since the contact time between the ball and the hitting portion is lengthened, the feeling that the ball is on the bat is obtained, and the hitting feeling is improved.

[Simple explanation of drawings]

[Figure 1]

It is a side partial cross-sectional schematic diagram which shows Embodiment 1 of the bat by this invention.

[Figure 2]

It is sectional drawing of the line segment II-II of FIG.

[Fig. 3]

It is a partial cross-sectional schematic diagram for demonstrating the 1st modification of Embodiment 1 of the bat according to this invention shown in FIG. 1 and FIG.

[Fig. 4]

FIG. 5 is a schematic side sectional view for explaining a second modification of the first embodiment of the bat according to the present invention.

[Fig. 5]

It is a side partial cross-sectional schematic diagram which shows Embodiment 2 of the bat by this invention.

[Fig. 6]

It is sectional drawing of the line segment VI-VI of FIG.

[Fig. 7]

It is a partial cross-sectional schematic diagram for demonstrating the concave part of the bat shown in FIG.

[Fig. 8]

It is a side partial cross-sectional schematic diagram which shows the modification of Embodiment 2 of the bat by this invention.

[Fig. 9]

It is the schematic schematic diagram of the experimental apparatus used for the repulsion experiment of the hitting part model.

[Fig. 10]

It is the schematic schematic diagram of the experimental apparatus used for the repulsion experiment of a bat.

[Explanation of symbols]

1 Baseball or softball bat, 2 Recess, 2a Bottom corner, 2b Top corner, 2c, 26 Side wall, 3 Elastic body, 4 Grip end, 5 Seat, 6 Central axis, 7 Bat base member, 8 Central part Bottom wall, 9 outermost part, 10 tip part, 11 hitting part, 11a hitting part center part, 11b tip side end, 11c taper part side end, 12 taper part, 13 grip part, 14 step part, 15 end area , 16 minimum inner diameter, 17 inner diameter enlargement, 20 pitching machine, 21 high speed video camera, 22 ball hitting model, 23 balls, 24 bat stand, 25 bats.