JP3919959B2 - Baseball bat - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a baseball bat and a method for manufacturing the same, which can reduce the impact force at the time of hitting to suppress the flight distance and avoid danger and can be used safely.
[0002]
[Prior art]
There is no reason why a regular bat must be used to check the batting form or improve the feeling of batting in baseball batting practice. In particular, since the practice of hitting is performed away from the actual battle, such as checking the form and checking the hitting position, the objective can be sufficiently achieved even with practice with a simulated bat. In particular, when hitting a ball directly, a certain amount of space is required even if it is protected by a net. In addition, when using a regular bat, there is a problem that consideration must be given to paying attention to outsiders in consideration of safety.
[0003]
On the other hand, if you enjoy playing baseball in a limited area, or if you and other unskilled players enjoy playing baseball, it is necessary to avoid this because batting is a dangerous action. In this case, there is no reason to use a regular bat with a high risk because there is no need to obtain a large flight distance.
[0004]
In the past, a simulated bat was proposed following a regular bat in view of such a situation, and the impact of the bat itself was reduced by molding the plastic bat and the entire bat with a low material risk with an elastic body. There has been proposed a bat that avoids the danger and can also enjoy baseball safely even in a narrow place by controlling the flight distance of the hit ball.
[0005]
One example is the baseball bat described in Japanese Patent Publication Nos. 59-10228 and 62-106784. These are made of foamed resin, and the bat itself is molded, or a baseball bat is manufactured by forming a striking part with an elastic material around a semi-rigid core. The purpose is to provide a highly bat.
[0006]
[Problems to be solved by the invention]
These conventional bats are sufficient for their intended safety, but the entire bat is made of an elastic material such as foamed resin, or a semi-rigid material is used for the core. Since it is soft as a whole, safety is ensured instead of lacking the rigidity that can be obtained from a regular bat. It was not enough to enjoy playing baseball.
[0007]
The present invention has been developed in view of such circumstances, and the object of the present invention is to ensure the safety during use and at the same time obtain a feeling of use close to that of a regular bat, and at the time of hitting, the flying of the hit ball. To provide a baseball bat that can be used safely at a reduced distance, and to manufacture a stable baseball bat that can be manufactured stably in consideration of durability and manufacturability. It is to be provided.
[0008]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention has a pipe core material that has the required rigidity and is lightweight, and has a grip portion that can be directly gripped at one end, and covers the entire length of the core material excluding the grip portion. The present invention also provides a baseball bat integrally formed with an elastic hitting portion made of a synthetic resin material having appropriate elasticity such as urethane foam.
The required rigidity of the core material, for example, aluminum pipe material, provides the rigidity and stability of the entire bat. On the other hand, by wrapping the entire length other than the grip part with an elastic material to reduce the impact force at the time of hitting, the danger at the time of swing is avoided, and further the flight distance of the hit ball It is to provide a baseball bat that can suppress the above.
[0009]
Further, the present invention will be described in detail. The feature is that a pipe material having a required length is used as a core material, a grip portion is set on one end side thereof, and the grip end is expanded at the end portion of the grip portion. Another object of the present invention is to provide a baseball bat in which an elastic striking portion having a required thickness is integrally formed on a circumferential surface extending over the entire length of the core member excluding the grip portion.
[0010]
Another object of the present invention is to provide a baseball bat characterized in that the base material is a lightweight metal pipe material.
[0011]
In the present invention, the grip end portion is formed as a circular body having a male screw portion, and is separated from the core material. On the other hand, a female screw portion is formed on the inner peripheral surface of the end opening of the grip portion of the core material. An object of the present invention is to provide a baseball bat in which a grip end portion is formed at an end portion of a grip portion by buttering the male screw portion on a screw portion.
[0012]
Another object of the present invention is to provide a baseball bat characterized in that the elastic hitting portion is formed of a synthetic resin foam having a required elasticity.
[0013]
Furthermore, in the baseball bat according to the present invention, the elastic hitting portion is gradually reduced in diameter from the middle of the length toward the boundary portion with the grip portion, while the grip portion is wound with a grip tape over the entire length. An object of the present invention is to provide a baseball bat which is formed by covering the surface of a core material.
[0014]
In addition to providing the above-described baseball bat, the present invention is intended to provide a method for efficiently and stably manufacturing the bat.
A metal pipe material is cut into a predetermined length to form a core material, and one end thereof is set as a grip portion, and an internal thread portion is formed on the inner peripheral surface of the end opening portion of the grip portion, and the other end Sealing the opening of
Inserting the core material along the center of a molding die that matches the outer shape of the baseball bat excluding the grip portion, and holding and fixing the grip portion exposed to the outside of the die When,
Injecting a foaming stock solution into the mold, foaming between the core material and the inner surface of the mold, solidifying and integrally forming an elastic striking part on the core material surface;
A step of demolding after the elastic striking portion is solidified;
A step of winding a grip tape on the surface of the grip part after demolding, and screwing a male thread part of a circular grip end member to a female thread part formed in an end opening of the grip part, Forming a part;
A baseball bat manufacturing method comprising:
[0015]
Furthermore, the present invention provides a method in which a needle hole is appropriately formed through the surface skin layer while the foaming stock solution is injected into the molding die to form an elastic impact portion in the above-described manufacturing method, while the foaming stock solution is solidified. Another object of the present invention is to provide a method for manufacturing a baseball bat, wherein the bubble cells in the hitting portion are communicated with each other.
[0016]
In the present invention, a metal pipe material is cut to a predetermined length to form a core material, one end thereof is set as a grip portion, and an internal thread portion is formed on the inner peripheral surface of the end opening portion of the grip portion. And sealing the opening at the other end,
The core material is inserted along the center portion of the molding die that matches the outer shape of the baseball bat excluding the grip portion, and the grip portion is held outside the die to hold the core material. Fixing the mold to the mold,
A foaming agent, a pigment, a weathering agent, etc. are mixed and added to the solution foaming stock solution in the mold, heated in the mold, liquid foamed between the core material and the inner surface of the mold, and solidified to be elastic. Forming the striking portion integrally on the core surface;
A step of demolding after the elastic striking portion is solidified;
A step of winding a grip tape on the surface of the grip portion after demolding, and screwing a male screw portion of a circular grip end member into a female screw portion formed in an end opening of the grip portion, thereby grip end Forming a part;
A baseball bat manufacturing method comprising:
Hereinafter, the present invention will be described based on examples, and the features thereof will be clarified.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
【Example】
1 to 3 show an example of a baseball bat according to the present invention. 1 is a front view with a part of the bat as a cross section, FIG. 2 is a front view of the central longitudinal section omitting the enlarged portion of the main part, and FIG. 3 is a cross-sectional view taken along line AA in FIG. 1 is a bat according to the present invention, 2 is a core material, 3 is a grip part, and 4 is an elastic hitting part.
[0018]
The core material 2 in this embodiment is an aluminum pipe material having a required wall thickness, which is obtained by cutting a pipe material manufactured in a long length into a predetermined length. This core material 2 is cut to a predetermined length (actually the length of the bat required), and then an internal thread portion 5 is formed on the inner peripheral surface of the opening at the end on the side where the grip portion 3 is to be formed. It is provided for mounting of the end member 6.
[0019]
The reason why the aluminum pipe material is selected as the material of the core material 2 is that it is light and rigid as a metal material and has a desired resilience, but it is easy to obtain a uniform material. In addition, it is excellent in manufacturability in mass production. In addition, one of the major reasons for selecting metal pipe materials such as aluminum pipe materials is that the core material is deformed by heat and foaming pressure when the elastic hitting part made of synthetic resin, which will be described later, is foamed, and the entire bat is deformed By being effective in preventing
[0020]
The grip portion 3 is determined by arbitrarily setting a range of a required length from one end side with respect to the core material 2. In other words, the minimum length range is arbitrarily determined from the balance based on the weight of the bat, based on the length that can be grasped with both hands.
[0021]
The grip portion 3 is substantially a part of the core material 2 and in the manufacturing process, the grip portion protects the hand, stabilizes the grip, further selects the thickness, or for decoration. The tape 7 is wound as will be described later.
Although a tape is selected here, a rubber tube or the like may be attached to replace the tape winding.
[0022]
On the other hand, the elastic hitting portion 4 is formed so as to wrap the entire length of the core material 2 excluding the grip portion 3, and the hitting portion 4 relaxes the impact force at the time of hitting by elasticity and suppresses the flight distance to the hitting ball. At the same time, when a human body is accidentally touched during use, a large impact force is applied like a regular bat to prevent injury. For this reason, rubber or a soft synthetic resin material having elasticity, particularly its foam, is suitable.
[0023]
In addition to the weight of the core material 2, the elastic hitting portion 4 is required to have an appropriate weight in order to approximate the entire weight to the weight of the regular bat, and to exhibit the required elasticity, In order to adapt to the diameter of the film, it is formed to have a predetermined thickness.
[0024]
Further, in this embodiment, the striking portion 4 resembles the outer shape of a regular bat, so that the diameter gradually increases toward the other end (tip) starting from the boundary with the grip portion 3 to form a tapered shape. In addition, the outer shape of the regular bat that is normally seen is shown in the figure so as to be aligned with a substantially constant diameter from the middle to the tip.
[0025]
The protective tape 7 wound around the grip portion 3 is wound in a spiral shape in a range extending from the boundary portion to the end portion of the hitting portion after the elastic hitting portion 4 is formed on the core material 2, and the end portion is taped. To prevent peeling.
After the tape is wound (or may be before the tape is wound), the grip end member 6 is attached to the female screw portion 5 of the end opening to complete the tape.
[0026]
Since the grip end member 6 is difficult to be integrally formed with the core material 2 and the cost is high, the grip end member 6 is formed separately from the core material and is attached later. Here, the metal shaft body 8 is used. A rubber crown 11 is provided so that the enlarged diameter portion 9 is provided at one end and a male screw portion 10 is formed on the other circumferential surface of the other end and a screw shaft body formed in a substantially bolt shape is used as a base to wrap the enlarged diameter portion 9 on the circumferential surface. It is assumed that it is formed by covering. The member 6 is assembled by screwing the male screw portion 10 to the female screw portion 5 of the core member, thereby forming a grip end portion.
[0027]
Although the structure of the baseball bat according to the present invention has been described with reference to the drawings, it will be described in detail through actual manufacturing.
The core material 2 is not particularly limited as long as it is a pipe material, but the material implemented here is an aluminum pipe material, and more specifically, the diameter of the pipe material on the premise of manufacturing a child bat. 21.5 mm, a length of 665 mm, and a pipe wall thickness of 1.75 mm are selected, and a female screw portion 5 is formed in advance on the inner peripheral surface of one end opening thereof.
[0028]
On the other hand, a case where a synthetic resin foam is used as the elastic hitting portion 4 and a urethane resin foam in this embodiment will be described. A molding die (not shown) is prepared for forming the hitting portion.
Here, the mold is premised on molding by the mold foam method, but when other resins, that is, various elastomers are selected as materials, an injection molding method can be adopted. Hereinafter, the manufacturing process will be described.
[0029]
First, the end of the aluminum pipe core member 2 obtained by forming the female screw portion 5 is sealed by fitting a stopper or by attaching a tape to the front end side opening portion of the core material 2 so as to infiltrate the resin liquid. Preventive measures are taken, and an adhesive is applied to the circumferential surface of the entire length of the core member 2 excluding the grip portion 3.
[0030]
The adhesive used here is for the purpose of integrating the core material 2 and the elastic hitting portion 4 described later. Needless to say, an adhesive that exhibits an adhesive force corresponding to the material forming the hitting portion 4 is used. You will be asked to choose.
[0031]
On the other hand, a molding die adapted to the outer shape of the bat that manufactures the inner shape is opened, and a release agent such as wax, soaps, or oil is applied to the inner surface, and a paint for coating the surface of the bat is applied. . At this time, the paint is selected in accordance with the material used for the elastic striking portion 4 described later.
[0032]
After the preparation of the mold, the core material 2 is inserted along the center of the mold from the end side where the adhesive is applied, and then the mold is closed and the entire adhesive is applied. The grip part 3 at the other end is placed outside the mold and is fixed to the mold in this state while being positioned at the center of the mold.
[0033]
After completing the setting of the mold, the mold is heated and held at 40 ° C. to 45 ° C., and a urethane resin foaming stock solution is injected, and foamed in the space between the mold inner surface and the outer peripheral surface of the core material 2. The elastic striking portion 4 made of urethane foam is solidified to cover the peripheral surface of the core material 2.
[0034]
In addition, in obtaining the urethane resin foaming stock solution, predetermined additives for polyurethane resin, such as a catalyst, a crosslinking agent (chain extender), a foaming agent, a foam stabilizer, a release agent, a colorant, a hydrolysis inhibitor, Additives such as antioxidants and ultraviolet absorbers are appropriately mixed and adjusted.
What is important at this time is the hardness of the elastic hitting portion 4 obtained by foaming and solidifying. Since this hardness directly affects the flying of the ball, it is necessary to pay attention to its setting. However, the range of hardness (JIS S6050) 60 to 70 is appropriate for safety in use.
[0035]
After the resin foaming stock solution injected in the mold is foamed and fills the space to form the shape of the hitting portion 4, it is solidified. Then, a needle hole is made through the surface skin layer of the foam and becomes independent inside. The foam cells communicate with each other.
The communication of the foamed cells is a measure for preventing deformation due to heat and pressure at the time of mold forming, and is effective for stabilizing the shape of the striking portion 4.
[0036]
After the resin is solidified, the mold is opened to remove the mold, and then the grip end member 6 is screwed with the male threaded portion 10 to the female threaded portion 5 at the end of the core member 2, and the grip 7 is taped 7 Wrapping will complete the manufacture of the bat.
The paint applied to the surface of the elastic striking portion 4 is effective in improving the weather resistance and heat and moisture resistance in addition to enhancing the decorative effect, and increases the durability of the bat itself.
[0037]
The baseball bat of the present invention can be mass-produced because the elastic striking portion 4 can be easily and uniformly formed by a molding die using urethane resin as a material as described above, and is provided at a low cost. can do.
[0038]
In producing the baseball bat, the elastic hitting portion 4 is the most important part for exerting its characteristics. For example, in the case of the foam, the density, the hardness, the tensile strength, the elongation rate, the tear strength. Needless to say, an appropriate value is selected in consideration of the purpose of use of the bat such as rebound resilience and strain, and the intended user.
[0039]
In particular, the foaming density and elongation rate mainly determine the impact force, and the hardness, tensile strength, and tear strength determine the durability thereof. Will be set.
Of course, in addition to the selection of such materials, the weight of the striking part is important from the balance of the entire bat, and it is necessary to select the appropriate length and diameter for each application and user. It goes without saying that there is.
[0040]
By the way, although the polyurethane resin was adopted as the material of the elastic hitting part 4, there are, for example, tolylene diisocyanate, diphenylmethane diisocyanate, tolidine diisocyanate, isophorone diisocyanate and the like as the polyisocyanate as the raw material, and as the polyol, for example, polyester polyol, There are polyether polyols, acrylic polyols, polybutadiene polyols and the like. What is necessary is just to select the material suitable for shaping | molding of the striking part calculated | required considering each characteristic.
[0041]
In the case of using the injection molding method for forming the striking part 4, a foaming agent, a pigment, a weathering agent, etc. are mixed with a thermoplastic elastomer, heated in an injection molding machine, melted and foamed, and injected into a mold and solidified. become.
Examples of resin materials in this case include polystyrene, polyolefin, polyurethane, polyester, polyamide, 1,2, polybutadiene, ethylene / vinyl acetate, polyvinyl chloride, natural rubber, fluororubber, and chlorination. There are polyethylene-based, trans-polyisoprene-based and the like.
[0042]
【The invention's effect】
Although the present invention has been described in detail based on the embodiment, the striking portion that hits substantially the entire bat excluding the grip portion is formed of an elastic material such as a resin foam. There is no worry that the hit ball will fly, so it is convenient when used for bats for tossball batting, etc. Also, since the impact force is small, it will not cause a large destructive force even if it hits a person accidentally, and there is no worry about injury etc. There is an advantage that can be used.
[0043]
In addition, the bat according to the present invention is stable because it can be directly gripped and batting a part of the core material with which required rigidity is ensured, and is not different from a regular wooden or metal bat. There is an advantage that it can be used by touch.
[0044]
In addition, since the rigid core material is embedded over the entire length of the bat according to the present invention, the core material in the central portion maintains the rigidity even if the impact at the time of impact is absorbed by the elastic impact portion. Since the shaft does not bend or deform, there is an advantage that there is no feeling of softness and a feeling of use similar to a regular bat can be obtained.
[0045]
Further, according to the manufacturing method of the present invention, the striking part can be formed by inserting the core material into the mold and injecting the resin foaming stock solution, and further, the tape is applied to the grip part which is a part of the core material. Since it can be manufactured by winding or mounting a cylindrical member and mounting a grip end member, there is an advantage that a uniform product can be mass-produced at low cost and can be provided at low cost.
[0046]
Furthermore, further, it is possible to easily obtain desired bats having different thicknesses by changing the mold shape, and it is possible to manufacture various products at low cost.
[Brief description of the drawings]
FIG. 1 is a front view with a cross section of a part of a bat.
FIG. 2 is a front view of a central longitudinal section, omitting a portion showing an enlarged main part.
FIG. 3 is a cross-sectional view taken along line AA in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Butt 2 Core material 3 Grip part 4 Elastic hitting part 5 Female thread part 6 Grip end member 7 Tape 10 Male thread part

Claims (4)

By cutting the lightweight metal pipe to a predetermined length to form a core material, with its one end to the grip portion to form a grip end portion at an end portion of the grip portion, except while the grip portion A synthetic resin foam is formed on the peripheral surface of the entire length of the core material so as to have a required thickness to form an elastic striking portion, and from the middle of the length of the elastic striking portion toward the boundary with the grip portion. The baseball bat is characterized in that the diameter is gradually reduced to adjust the outer shape of the bat, and a grip tape is wound around the entire length of the grip portion to cover the exposed surface . 2. The baseball bat according to claim 1, wherein the grip end portion is a circular grip end member having a male screw portion and is formed separately from the core material, and the inner periphery of the end opening of the grip portion of the other core material. the surface forms a female threaded portion, baseball bat is characterized in that by screwing the male threaded portion to said female threaded portion to form a grip end portion to the grip portion end. A core that cuts a metal pipe material to a predetermined length, sets one end thereof to a grip portion, forms an internal thread portion on the inner peripheral surface of the end opening portion of the grip portion, and seals the opening portion of the other end Material molding process;
The core material is inserted along the center portion of the molding die that matches the outer shape of the baseball bat excluding the grip portion, while the core material is held while the grip portion is exposed to the outside of the die. Fixing to the mold,
And a step of integrally formed on the surface of the core material is foamed, the elasticity striking part is solidified between the foaming stock solution injected the core material and the inner surface of the mold into the mold,
A step of demolding after solidification of the elastic striking part,
The screwed a male threaded portion of the circular grip end member tapes grip step of winding, and the female screw portion formed at an end portion opening of the grip portion to the demoulding after the grip surface, the grip end Forming a part;
The manufacturing method of the baseball bat which consists of. A core that cuts a metal pipe material to a predetermined length, sets one end thereof to a grip portion, forms an internal thread portion on the inner peripheral surface of the end opening portion of the grip portion, and seals the opening portion of the other end Material molding process;
The core material is inserted along the center portion of the molding die that matches the outer shape of the baseball bat excluding the grip portion, while the core material is held while the grip portion is exposed to the outside of the die. Fixing to the mold,
A foaming agent, pigment, weathering agent, etc. are mixed and added to the solution foaming stock solution in the mold, heated in the mold, liquid foamed between the core material and the mold inner surface, solidified, and elastic Forming the striking part integrally on the surface of the core material;
A step of demolding after solidification of the elastic striking part,
The screwed a male threaded portion of the circular grip end member tapes grip step of winding, and the female screw portion formed at an end portion opening of the grip portion to the demoulding after the grip surface, the grip end Forming a part;
The manufacturing method of the baseball bat which consists of.

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