JP2007029559A - Bat for ball game and formation method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bat for ball games which can preserve display performance on it even under a prolonged period of use and provide its formation method. <P>SOLUTION: A recess 1A hollowed in the surface of a bat body 1 is formed on a hitting part A4 and a character/decoration display 2 is applied on the bottom surface of the recess 1A while an elastic layer 3 made of a transparent rubber based or a synthetic resin based material is disposed in the recess 1A. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a ball game bat, and more specifically, for a ball game in which a hitting portion is formed with a recess in which the surface of the bat main body is recessed, and an elastic layer made of a rubber or synthetic resin material is provided in the recess. The present invention relates to a bat and a method for forming the bat.

Ball game bats differ in terms of the size and hardness of the ball to be hit depending on the type of ball game such as hard baseball, soft baseball, softball, etc., so there is a dedicated bat for each. Yes.
These ball bats were originally made of wood, but in recent years, in addition to wooden bats, they are mainly made of aluminum that is durable and has a great flight distance. Metal bats and carbon bats such as FRP that are bent from this metal bat are manufactured, and a concave portion in which the surface of the bat body is recessed is formed in the striking portion. A ball game bat provided with an elastic layer is also manufactured.
In such a ball game bat, characters / decoration displays such as trademarks, designs, decorations, etc. are mainly printed on the outer surface of the hitting portion of the bat body, and a soft elastic layer is provided in the recess of the hitting portion. In some cases, a display is printed on the inner surface of a transparent sheet of a synthetic resin having a thickness of 0.1 mm to 1 mm provided as a protective layer on the outer surface of the elastic layer (see Patent Document 1).

Japanese Patent Laying-Open No. 2003-19236 (page 9-10, FIG. 4)

However, in the display structure of the wooden bat, metal bat, and carbon bat described in the former, the damage is likely to be caused by hitting, which tends to cause dullness, and the transparent sheet of the synthetic resin itself is torn. In addition, there is a problem that the appearance of the bat is deteriorated such that the visibility of the character / decorative display decreases as the number of uses increases.
Further, in the display structure of the ball game bat described in the latter, the display is located at the boundary between the soft elastic layer and the thin protective layer, so that a large impact force is generated from the thin protective layer. There is a problem that the display is likely to be damaged due to deformation due to the elastic deformation of the elastic layer due to the addition and the impact at the time of impact.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a ball game bat capable of maintaining display characteristics in a bat over a long period of use, and a method for forming the ball game bat. The point is to provide.

  The characteristic configuration of the first ball game bat of the present invention is that the hitting portion is formed with a recess having a concave surface on the surface of the bat body, and a character / decorative display is provided on the bottom surface of the recess. Is provided with an elastic layer made of a rubber-based or synthetic resin-based material having transparency.

  According to the above characteristic configuration, since the character / decorative display is applied to the bottom surface of the concave portion of the hard bat body, it forms a display structure that is difficult to peel off, and the impact at the time of hitting the ball directly affects the character / decorative display. Since the character / decoration display is applied to the bottom surface of the concave portion through a thick elastic layer, there is no deterioration in display such that the character / decoration display is peeled off.

  Therefore, the wooden bat, the metal bat, the carbon bat on which the character / decoration display is printed on the outer surface of the bat striking portion as in the prior art, and the outer surface of the elastic layer provided in the recess formed in the bat striking portion. In addition, the visibility of character / decorative displays should be ensured over a long period of time compared to a ball bat with a transparent, thin-walled protective film coated with a transparent, thin-walled inner surface. Therefore, the display property of the bat can be improved.

  The characteristic configuration of the second ball game bat of the present invention is that the elastic layer has a thickness of 2 mm to 8 mm.

  According to the above-mentioned characteristic configuration, it is possible to form a thick elastic layer that does not directly affect the character / decorative display when hitting the ball, and the character / decorative display applied to the bottom surface may be peeled off. In addition to forming a thickness sufficient for protection without causing display degradation, the lens effect is such that the character / decoration display can be seen through the thick elastic layer. Can be generated.

  Therefore, in addition to maintaining the visibility of the character / decorative display over a long period of use, it is possible to improve the appearance of the bat by providing a lens effect.

  The third feature of the ball game bat of the present invention is that the elastic layer has a rubber hardness (Shore A) set to 40 to 90 degrees.

According to the above characteristic configuration, the ball side is restored from the deformed state due to the collision due to the hit between the time when the hit ball starts to hit the elastic layer of the hitting portion and the time when the ball is separated from the elastic layer by repulsion in the above setting range. After the elastic layer side receives the deformation of the ball due to the collision with the viscoelasticity, the elastic state of the elastic layer and the elastic layer are substantially synchronized with respect to the ball state in which the elastic layer is separated from the elastic layer, Realization of high resilience to the ball and high flight distance becomes possible.
Here, when the rubber hardness is 40 degrees or less, the elastic layer becomes too soft and the elastic layer is easily detached from the recesses during the use process. On the contrary, when the rubber hardness is 90 degrees or more, the elastic layer is too hard. As a result, the elastic restoring force of the viscoelasticity at the time of hitting becomes extremely fast, and the flying distance tends to be suppressed by detaching from the elastic layer in a state where the ball side cannot be elastically restored.
In addition, since the rubber hardness of the elastic layer is set to 40 to 90 degrees, it is difficult for soil, mud, dust or the like to adhere to the surface of the elastic layer or to be damaged, and high transparency. It has been proved by experiments that it can be maintained, and is set to make full use of the transparency of the elastic layer. This is because when the rubber hardness of the elastic layer having transparency is 40 degrees or less, soil, mud, dust and the like are easily attached and difficult to remove, and when the rubber hardness of the elastic layer is 90 degrees or more, for example, As in the case where an elastic layer is formed from a urethane resin, there is a tendency to show a decrease in the transparent quality, such that the transparency is lowered and becomes white.

  Therefore, compared to a general ball game bat that does not have an elastic layer in the hitting part, for example, during a game where dirt, mud, dust, etc. are likely to adhere, the character / decoration display has high visibility, In addition, excellent bat performance can be exhibited in terms of flight distance and the like.

  In the fourth feature configuration of the ball game bat of the present invention, the elastic layer has a storage elastic modulus of 9 to 19 MPa at a temperature of 20 ° C. and a frequency of 100 Hz.

  According to the above characteristic configuration, in particular, when the ball hit at the hitting part is hit with the bat axis slightly off the upper part, a large storage elastic modulus acts in addition to an appropriate frictional force. In the state where the ball is turned to repulsion, it is possible to easily form a state of flying with a high repulsive force at an angle with good flight distance.

Therefore, even when the ball hit by the hitting portion is hit with the bat axis slightly off, the hit ball can be hit with a high repulsive force at an angle with good flight distance. It is possible to improve the impact performance.
Here, conventionally, there is an elastic layer whose impact performance is improved by having a storage elastic modulus of 1.4 Mpa or less at a temperature of 20 ° C. and a frequency of 100 Hz (Japanese Patent Laid-Open No. 2004-242738). However, since the storage elastic modulus belongs to the region lower than 9 to 19 Mpa which is the storage elastic modulus of the present invention, the knowledge that the conspicuousness exists also in the high region due to the difference in the conditions such as rubber hardness. It has gained.

  According to the characteristic configuration of the fifth ball game bat of the present invention, the end of the recess is formed in a curved shape that gradually becomes deeper toward the bottom, and at least the base agent is applied to the end of the recess. The elastic layer is joined through the gap.

  According to the above characteristic configuration, for example, when the end of the recess has a right-angled inner corner shape, and a hit ball corresponds to the end of such a recess, stress concentration occurs in the bat body via the right-angled inner corner shape. In addition, compared with the problem that the bat body is deformed or broken, the end of the recess is curved, and the end of the recess and the elastic layer are integrally joined via the base agent. When the hit ball corresponds to the end of the recess, the stress is distributed to the bat body via the elastic layer integrally joined to the curved end without causing the elastic layer to be displaced from the recess and damaging the elastic layer. Thus, the bat body can be prevented from being deformed or broken.

  Accordingly, since the bat body can be maintained against concentrated stress due to the hit ball while maintaining the high resilience of the elastic layer, a highly reliable ball game bat can be formed.

According to the characteristic configuration of the sixth ball game bat forming method of the present invention, the display for applying the character / decoration display to the bottom surface of the concave portion in which the hitting portion surface of the bat main body is recessed all around. Forming process;
A base layer forming step of applying a base agent to the concave portion of the hitting portion on which the character / decorative display is applied;
In the striking part of the bat body in a vertical position where the bat center axis is substantially vertical, a split mold having an inner peripheral surface formed in the surface shape of the striking part is placed in a surrounding state to form a mold, A mold installation process for forming a filling space between the mold and the mold;
An elastic layer filling step of filling the filling space without gaps from the lower part of the space to the upper part by pouring an elastic material having transparency in a fluid state through an injection path communicating with the upper end of the space;
A deaeration process for naturally flowing out air bubbles mixed in the elastic material by filling from the injection path;
It waits for the filled elastic material to harden and then removes the bat body from the mold to complete a ball game bat in which an elastic layer is integrally formed at the hitting portion.

  According to the above characteristic configuration, the elastic layer, which is entirely cylindrical, is integrated with no gap in the recess of the hitting portion of the bat main body, and is uniformly uniform by eliminating bubbles and the like. An elastic layer having transparency can be formed.

  Therefore, the concave portion and the elastic layer can be integrally joined without a gap, and even in a usage environment where dust or rainwater adheres to the surface of the bat when using the bat, such a case is present at the joint boundary between the concave portion and the elastic layer. Therefore, it is possible to improve the display performance such that the character / decoration display displayed in the concave portion through the elastic layer can be visually recognized even in a bad environment.

  Hereinafter, a ball bat to which the present invention is applied will be described with reference to the drawings.

Embodiment
In this embodiment, an example in which the present invention is applied to a ball bat A for soft baseball will be described with reference to the drawings.
In this ball game bat A, as shown in FIGS. 1 (a), (b), and (c), a grip A2, a taper part A3, and a hitting part A4 are continuously formed from the grip end A1 at the base end along the tip. ing.
The bat main body 1 constituting the skeleton portion that is the base of such a ball game bat A is formed of FRP (fiber reinforced plastic).

  The ball game bat A is formed with a recess 1A in which the surface of the bat main body 1 is recessed over substantially the entire length of the hitting portion A4, and a character / decoration display 2 is provided on the bottom surface 1B of the recess 1A. In addition, an elastic layer 3 made of a rubber-based or synthetic resin-based material having transparency and high hitting ball resilience is provided in the recess 1A.

  1 A of said recessed parts are formed over the perimeter of striking part A4, and the edge part 1C of the butt front end side and butt base end side in this recessed part 1A is formed in the curved shape which becomes deep gradually toward the bottom part 1, and others. The depth of the portion is configured uniformly.

  The bottom surface 1B of the recess 1A is coated with a base material 4 made of a polyurethane base material having the same type of transparency as the material constituting the elastic layer 3 on the top surface on which the character / decorative display 2 is applied. The elastic layer 3 is integrally joined to the recess 1A through the base material 4.

  Further, since the elastic layer 3 corresponding to the end portion 1C of the recess 1A is integrally joined by the base material 4, even when the ball is hit with the elastic layer 3 corresponding to the end portion 1C, the elastic layer 3 is not recessed. The striking can be supported without shifting with respect to 1A. Therefore, the impact force of the ball when hit with the elastic layer 3 corresponding to the end 1C is received by the curved portion of the end 1C, so that the stress due to the hit is well dispersed and concentrated on the bat body 1. The joint structure is free from stress.

  The bat body 1 is formed of, for example, a hollow shell made of FRP material and having a thickness of about 4 mm. The total length is about 840 mm. The so-called sweet point is set.

  The elastic layer 3 is made of a polyurethane resin, which is an artificial rubber material having a rubber hardness (Shore A) of 40 degrees to 90 degrees, preferably 55 degrees to 70 degrees. Since the polyurethane resin is rich in reactivity, it is used as both a thermosetting resin and a thermoplastic resin. In this embodiment, casting polyurethane is used.

  The polyurethane resin used has a specific gravity of about 1.03 and a rubber hardness in the range of 70 degrees to 72 degrees, and the amount filled in the space of the recess 1A where the striking part A4 is formed is the total amount of bat The weight is set not to exceed the weight.

In this embodiment, the depth of the concave portion 1A of the striking portion A4 is about 4 mm, and the thickness of the elastic layer 3 provided on the concave portion 1A is also about 4 mm.
In this embodiment, it has been found that a high ball hitting repulsion is formed from a thickness of a minimum thickness of about 2 to 3 mm, which forms a high hitting ball repulsion in the elastic layer 3, which is a difference from the recess 1A. About 2 to 1 mm, the bat weight is optimized by adding the shortage of the bat weight.

  Therefore, in the ball game bat A according to the embodiment, it is possible to form an elastic layer structure having a high resilience in the entire hitting portion A4 while being able to form the ball game bat A having an appropriate bat weight. .

  Further, by adding the thickness dimension of the elastic layer 3, higher hitting ball resilience is formed, but by further increasing the thickness of the elastic layer 3, the resilience coefficient is increased and the hitting distance is improved. However, it is also known that there is an upper limit, and that the resilience does not change even if the thickness is increased beyond this upper limit. Therefore, by forming bats having different wall thicknesses within a range where the hit ball is repelling, it is possible to form a bat having an optimum weight corresponding to the user.

  The character / decoration display 2 is pre-printed with a product name or pattern on the bottom surface 1B of the recess 1A, for example, silk screen printing, pad printing, engraving, or a product name or pattern on the surface, and is adhered to the back surface. It is applied by sticking a sticking sheet provided with a layer or transferring it with a water transfer seal or a heat transfer seal.

  The elastic layer 3 is integrally joined to the recess 1A with a polyurethane resin base material 4 applied to the bottom surface 1B interposed therebetween.

Next, a method for forming the ball game bat A will be described.
First, the bat body 1 itself is formed from a wooden material that is an original bat material, formed from a metal material mainly composed of aluminum, or formed from FRP. . In the case of the bat body made of the wood material, a recess can be formed in the hitting portion by cutting, and in the case of the bat body made of the metal material, the recess can be formed in the hitting portion by narrowing.

  The bat body 1 made of the FRP is formed as follows, for example.

  First, a sheet-like prepreg made of carbon fiber and glass fiber impregnated with a thermosetting resin (epoxy) is placed on a mandrel, which is a taper-rod-shaped core with a length of 1 bat body, with a uniform layer thickness throughout. Winding is performed to form a first in-process forming body corresponding to the butt portion from the grip A2 through the tapered portion A3 to the hitting portion A4. Also, although not shown in the drawing, a second in-process forming body formed in a cylindrical shape corresponding to the shape of the butt tip and a third in-process forming body formed in a ring shape corresponding to the form of the grip are prepared.

  Next, the first to third in-process forming bodies are housed in corresponding positions in a two-part matching mold in which an inner peripheral surface corresponding to the concave portion 1A over the entire circumference of the striking portion A4 is formed, and A long tube formed of soft PVC or the like is accommodated in the inside of the hole formed in the end portion of the first in-process forming body.

  Next, heat molding is performed in this state. At the time of molding, air is press-fitted into the tube, and the first to third in-process formation bodies are integrally joined, and a rough portion along the mold as shown in FIG. A bat body 1 'is formed.

  Next, after removing the rough bat body 1 ′ from the mating mold C, removing the debulked tube from the rough bat body 1 ′ through deburring and the like, filling the hole in the grip end with epoxy resin and closing it. Surface polishing with putty is performed for the purpose of closing the pinhole.

  Next, after the primer treatment is performed on the surface of the rough bat main body 1 ′, the base is coated with a polyurethane-based paint to form the bat main body 1 as shown in FIG.

  Next, a forming method for forming the elastic layer 3 through which the character / decorative display 2 can be seen through on the bat body 1 formed in this way will be described.

  As shown in FIG. 2 (c), a character / decoration display 2 for displaying a product name, a pattern, etc., on the recess 1A in which the surface of the hitting part A4 of the bat body 1 is recessed over the entire circumference, as shown in FIG. Apply by screen printing, pad printing, water transfer seal, thermal transfer seal, engraving, etc. (Display formation process)

  Next, a base material 4 made of polyurethane is further applied to the concave portion 1A of the hitting portion A4 to coat the character / decorative display 2. (Underlayer forming process)

Next, as shown in FIG. 3, the split mold in which the inner peripheral surface is formed in the outer surface shape of the striking portion A4 from the striking portion A4 to the tip portion of the bat main body 1 in the vertical posture in which the bat center axis is vertical. The mold C is formed by installing the CA in an enclosed state, and a filling space S is formed between the striking part A4 and the mold C. (Mold setting process)
Here, a release agent 6 is coated on the inner surface of the mold C.

  Next, as shown in FIG. 4 (a), from the polyurethane resin material having transparency in the fluidized state through the injection path S2 communicating with the upper space S1 with the gate G opened with respect to the filling space S. The elastic material 3 ′ to be formed is injected through the injection tool 7 and filled from the space lower part S3 to the space upper part S1 without a gap. (Elastic layer filling process)

  Here, the mold C in this embodiment is provided with a gate G corresponding to each divided mold CA.

  Next, the air bubbles mixed in the elastic material 3 'by filling are naturally discharged from the filling space S to the outside via the injection path S2 and the communication path S2a. (Deprivation process)

  Next, as shown in FIG. 4B, after the mold C is pre-heated through the heating means 5 such as a heater with the gate G closed, the mold C is removed from the mold C, and then the heating furnace The elastic material 3 ′ is cured in a heated atmosphere such as a ball game bat A in which an elastic layer is integrally formed at the hitting portion. (Die removal process)

  Next, the release agent is wiped off, and a grip tape is wound around the grip A2 of the ball bat A according to the type of the bat.

  According to the ball game bat A having such a configuration, the elastic layer 3 has high resilience to the hit ball while the character / decorative display 2 can be visually recognized due to the presence of the elastic layer 3 in the hitting part A4. Can respond to a hit ball. Moreover, it is possible to form a thick elastic layer 3 that does not directly impact the character / decoration display 2 when hitting a ball, and the character / decoration display 2 applied to the bottom surface 1B is peeled off. Such display deterioration does not occur.

  In addition to forming a thick elastic layer 3 without bubbles, the entire elastic layer can have uniform transparency, and in addition to forming a sufficient thickness for protection, It is possible to produce a lens effect that the decorative display can be seen through the thick elastic layer.

[Experimental example]
A comparison experiment between a ball bat A in which the elastic layer 3 is formed on the hitting portion A4 of the FRP bat main body 1 and a metal bat (for soft baseball).

<Contrast condition>
A ball game bat A having a total length of 840 mm and a ball hitting position set to the center position of the hitting portion A4 150 mm before the tip of the bat main body is used.
As the elastic layer 3, a layer having a specific gravity of about 1.03 and a rubber hardness in the range of 70 to 72 degrees was used.
The dynamic storage elastic modulus of the elastic layer 3 is 11 to 16.5 Mpa in a frequency dispersion measurement at a measurement temperature of 20 degrees and a frequency of 100 Hz, and 10 to 15 Mpa in a frequency dispersion measurement at a measurement temperature of 25 degrees and a frequency of 10 Hz. What was in the range was used. Here, conventionally, there is an elastic layer whose impact performance is improved by having a storage elastic modulus of 1.4 Mpa or less at a temperature of 20 ° C. and a frequency of 100 Hz (Japanese Patent Laid-Open No. 2004-242738). However, the storage elastic modulus belongs to a region lower than 9 to 19 Mpa which is the storage elastic modulus of this embodiment, and conventionally, the elastic layer has a storage elastic modulus at a temperature of 25 ° C. and a frequency of 10 Hz. Although there exist what aimed at the improvement of impact performance by being 0.01 Mpa-6Mpa (JP, 2004-242738), the area | region where the storage elastic modulus is lower than 9-16 Mpa which is the storage elastic modulus of this embodiment Therefore, it has been found that, depending on the difference in conditions such as rubber hardness, the experimental conditions are the same, but there is another conspicuousness even in high regions.

  The dynamic loss elastic modulus of the elastic layer 3 is about 0.5 to 1 Mpa in frequency dispersion measurement at a measurement temperature of 20 degrees and a frequency of 100 Hz, and 0.4 in frequency dispersion measurement at a measurement temperature of 25 degrees and a frequency of 10 Hz. The one in the range of about 0.7 Mpa was used.

  An example of repeatedly measuring the ball rebound speed immediately after hitting by changing the bat batting speed (bat speed) and the ball speed (using a soft ball) under these conditions is shown.

<First experiment result>
In the metal bat, the batting speed was 111.82 Km / h, the ball speed was 104, 29 Km / h, and the ball repulsion speed was 112.28 Km / h.
In the bat that forms an elastic layer in the hitting portion, the batting speed is 109.53 Km / h, the ball speed is 104.59 Km / h, and the ball repulsion speed is 118.10 Km / h. An increase of 5.18% in speed was observed.

<Second experiment result>
The metal bat had a batting speed of 103.39 Km / h, a ball speed of 95.71 Km / h, and a ball repulsion speed of 99.0 Km / h,
Bat that forms an elastic layer in the striking part: Batting speed is 98.65 Km / h, ball speed is 95.91 Km / h, ball repulsion speed is 107.17 Km / h, and the ball rebound speed is higher than metal bat. An increase of 8.24% was confirmed.

<Discussion>
Although it was a comparison experiment in the approximate range, a significant difference was seen in the rebound velocity of the ball, confirming the improvement in the flight distance of the ball.

  The reason why the rebound speed of the ball is higher than the slower one of the bat and the ball is faster than the faster one is as described above. It is presumed that a high repulsive force acts on the ball because the elastic recovery of the viscoelasticity of the elastic layer on the side of receiving the ball tends to be synchronized with the elastic recovery of the deformed ball.

  In addition, in the soft baseball bat, the ball rebound speed was better in the low hardness region than in the high hardness region, and good results were not obtained when the rubber hardness was 70 or more. In a similar experiment with a softball bat having an elastic layer at the hitting portion and a softball, good results were obtained up to a rubber hardness of 90 degrees in the high hardness region.

  Although the above comparison experiment was performed corresponding to each numerical value of rubber hardness between 40 degrees and 90 degrees, the same tendency was shown in the results, and the correlation was recognized within the above hardness range. When the hardness was 40 degrees or less or 90 degrees or more, good results were not obtained in the ball rebound speed.

  Experiments have shown that by setting the rubber hardness of the elastic layer in the range of 40 to 90 degrees, it is difficult for soil, mud, dust, etc. to adhere to or scratch the surface of the elastic layer. The hardness is set to take full advantage of the transparency of the elastic layer. This is because when the rubber hardness of the elastic layer having transparency is 40 degrees or less, dirt, mud, dust, etc. are easily attached and difficult to remove, and when the rubber hardness of the elastic layer is 90 degrees or more, it is transparent. It was difficult to mold and showed a tendency to form a white cloudy elastic layer.

[Another embodiment]
1) Although the depth of the concave portion 1A of the striking portion A4 in each of the above embodiments has been described as having a uniform depth except for both ends, the present invention is not limited to this, as shown in FIG. In the vicinity of the center of the hitting portion A4, the depth of the recess is the smallest and the depth of the recess is shallowest, and the depths of the recesses h2 and h3 increase from the center to the butt tip side and from the center to the grip side. The elastic layer 3 may be provided with a thickness dimension corresponding to the depth dimensions h1, h2, and h3.

  In this case, when the ball is hit at the center of the hitting portion A4 by setting the minimum thickness dimension that forms a high hitting ball resilience, the thickness dimension of the elastic layer 3 corresponding to the minimum depth portion is high. In addition to being able to form a striking state with a high flight distance by acting on the ball, for example, even if the ball is hit at a part deviating back and forth from the center of the hitting part, the minimum depth that causes high resilience The ball is hit by the elastic layer 3 deeper than the size, and a high repulsive force can be imparted to the ball while the hit is off the center of the hitting portion A4, so that the hitting performance can be improved.

2) In the above-described embodiment, an example in which the substantially elastic striking portion A4 and the wide elastic layer 3 are formed over the entire circumference has been described. However, the present invention is not limited thereto, and the striking portion A4 has a substantially full length. And the structure which forms the wide elastic layer 3 over the perimeter may be sufficient.
Further, the elastic layer 3 may be formed only in a specific range including the center of the striking portion A4 without extending over the substantially entire length and the entire circumference of the striking portion A4.

3) In the above embodiment, an example in which the bat body 1 forms a ball game bat using FRP as a bat material has been described. However, the present invention is not limited to this, and is applied to a ball game bat using wood as a bat material. Alternatively, it may be applied to a ball game bat made of metal as a bat material, or may be applied to a ball game bat formed by integrally combining bat parts made of bat materials having different hitting parts and grip parts. .
In the above embodiment, an example in which the present invention is applied to a ball game bat which is a soft baseball bat has been described. However, the present invention is not limited thereto, and is not limited to this. The present invention may be applied to a bat or the like.

  4) In the above embodiment, the elastic layer 3 of the striking portion A4 has been described as being formed by thermosetting a polyurethane material made of casting polyurethane. However, the present invention is not limited to this, and the elastic layer of the striking portion A4. 3, the polyurethane material may be formed by thermoplasticity.

  5) The elastic layer 3 of the above embodiment has been described as being formed from a polyurethane material made of transparent casting polyurethane. However, the present invention is not limited to this, and has transparency and rubber hardness. Silicone rubber, olefin (polypropylene, polyethylene, etc.) elastomer, halogen (vinyl chloride) elastomer, styrene (polystyrene, etc.) elastomer, or a composite thereof It may be a composite material or the like.

  6) In the above embodiment, an example in which the elastic layer 3 is integrally bonded to the concave portion 1A through the base material 4 coated on the entire bottom surface 1B of the concave portion 1A in the hitting portion A4 has been described. However, the elastic layer may be integrally joined to at least the end portion of the recess via a base material.

7) In the above embodiment, in the mold C for forming the elastic layer 3 on the bat body 1, the example in which the gate G is provided corresponding to each divided mold CA has been described. As shown in (b), the same effect can be obtained by using a mold C provided with a gate G in one split mold CA.
In addition, the same code | symbol is attached | subjected to the same component as the said embodiment, and the detail is abbreviate | omitted.

  8) The mold C according to each of the above embodiments closes the gate G so as to block the communication state between the filling space S and the injection port S2, and makes the filling space S in the mold C isolated. As described above, the present invention is not limited to this. For example, as shown in FIG. 7, an open inlet S <b> 2 is formed on the upper part of one pair of split molds CA, and both split molds CA are combined. In this state, a communication path S2a in which the injection port S2 and the filling space S communicate with each other is formed in the other split mold CA, and the installation state in which the injection port S2 communicates with the upper end portion of the recess 1A of the striking portion A4. Thus, the mold C may be formed in the lower part of the butt tip part and in the lower part of the mold space 8 in which the bat body 1 can be moved downward.

  In the case of this mold C, as shown in FIG. 7 (a), the elastic material 3 ′ is injected into the filling space S through the injection path S2 through the injection tool 7, and the lower space S3 of the filling space S is obtained. After filling from the injection path S2 to the injection path S2, the air bubbles mixed in the elastic material 3 'are naturally discharged from the filling space S to the outside via the injection path S2 and the communication path S2a.

  Then, as shown in FIG. 7 (b), the bat body 1 is pushed down toward the lower mold space 8 relative to the mold C, and the communication state between the filling space S, the inlet S2, and the communication passage S2a is established. In addition to shutting off, the filling space S is isolated in the mold C, and the elastic material 3 ′ filled in the filling space S is pre-heat-molded, and after demolding from the mold C, a heating furnace, etc. The ball material bat A in which the elastic layer 3 is integrally formed at the hitting portion can be formed by curing the elastic material 3 ′ in a heated atmosphere. Here, the air in the mold inner space 8 below the mold C is released from the joint between the divided molds CA when the bat body 1 is pushed down.

  According to such a forming method, it is possible to form the elastic layer 3 having a good surface quality. Further, for example, in a mold type as shown in FIGS. 4 and 6, the elastic material 3 ′ is filled in the filling space S. Since the injection port S2 is opened when the filling is completed and the injection port S2 is closed when the filling is completed, the closing surface of the gate G corresponds to the upper space S1 of the filling space S, and the surface of the elastic layer 3 is slightly The quality can be improved without leaving such traces as compared with those that leave traces.

  Subsequently, as this other mold C, for example, as shown in FIG. 8, an open inlet S2 is formed at the upper part of a pair of one split mold CA, and both split molds CA are combined. A communication passage S2a in which the injection port S2 and the filling space S communicate with each other through the gate G is formed in the other divided mold CA, and the upper end of the injection port at the upper part of the mold and the recess 1A of the striking part A4. A mold internal space 8 in which the bat main body 1 can be moved downward may be formed in the lower part of the butt tip in the installed state where the parts communicate.

  In the case of such a mold C, as shown in FIG. 8A, the gate G is opened, and the elastic material 3 ′ is injected into the filling space S through the injection path S2 via the injection tool 7. After filling from the lower space S3 of the filling space S to the injection path S2 without a gap, the air bubbles mixed in the elastic material 3 'by filling are transferred from the filling space S to the outside via the injection path S2 and the communication path S2a. Let it flow naturally.

  Then, as shown in FIG. 8B, the gate G is closed to cut off the communication state between the filling space S, the inlet S2 and the communication passage S2a, and the bat body 1 is placed below the mold C. After pushing down toward the mold space 8, the filling space S is isolated in the mold C, and the elastic material 3 'filled in the filling space S is preheated and then removed from the mold C. After that, the elastic material 3 ′ is cured in a heating atmosphere such as a heating furnace to form the ball game bat A in which the elastic layer is integrally formed on the hitting portion.

Even in such a forming method, the elastic layer 3 having a good surface quality can be formed. Further, for example, in the mold type as shown in FIGS. 4 and 6, the elastic material 3 ′ is provided in the filling space S. When filling, the injection port S2 is opened, and when the filling is completed, the injection port S2 is closed, so that the closing surface of the gate G corresponds to the upper space S1 of the filling space S, and the surface of the elastic layer 3 is slightly increased. Compared with what leaves a trace, quality can be improved without leaving such a trace.
In addition, the same code | symbol is attached | subjected to the same component as the said embodiment, and the detail is abbreviate | omitted.

An explanatory view showing the structure of a ball game bat to which the present invention is applied (a) is an explanatory view showing the appearance of the bat (b) is an explanatory view showing an elastic layer of a hitting section in cross section (c) is a cross section of the entire bat Explanatory diagram An explanatory view showing a method for forming a ball game bat (A) is an explanatory view showing a rough bat main body in which a concave portion is formed in a hitting portion by a mold (B) is an explanatory view showing a bat main body having a concave portion formed in the hitting portion. (C) is an explanatory view showing a bat body with a character / decoration display on the bottom of the recess. Simplified longitudinal sectional view showing a state where the hitting part of the bat body is installed in the mold An explanatory diagram (a) showing a method for forming an elastic layer is an explanatory diagram showing a state in which an elastic material is filled in a filling space in a mold (b) is an explanatory diagram showing a state in which preheating is performed The principal part expanded sectional view of the bat for ball games to which the present invention is applied An explanatory view (a) showing a method for forming an elastic layer to which the present invention is applied is an explanatory view showing a state in which an elastic material is filled in a filling space in a mold (b) is an explanatory view showing a state in which preheating molding is performed An explanatory view (a) showing a method for forming an elastic layer to which the present invention is applied is an explanatory view showing a state in which an elastic material is filled in a filling space in a mold (b) is an explanatory view showing a state in which preheating molding is performed An explanatory view (a) showing a method for forming an elastic layer to which the present invention is applied is an explanatory view showing a state in which an elastic material is filled in a filling space in a mold (b) is an explanatory view showing a state in which preheating molding is performed

Explanation of symbols

A Ball game bat A4 Strike part 1 Bat body 1A Recess 1B Bottom 1C End 2 Character / decoration display 3 Elastic layer 3 'Elastic material

Claims (6)

  The striking part is formed with a concave part with the concave surface of the bat body, and a character / decorative display is provided on the bottom of the concave part, and the concave part is made of a rubber-based or synthetic resin-based material having transparency. Ball game bat provided with an elastic layer.   The ball bat according to claim 1, wherein the elastic layer has a thickness of 2 mm to 8 mm.   The ball bat according to claim 1 or 2, wherein the elastic layer has a rubber hardness (Shore A) of 40 degrees to 90 degrees.   The ball bat according to claim 1, wherein the elastic layer has a storage elastic modulus of 9 to 19 MPa at a temperature of 20 ° C. and a frequency of 100 Hz.   The end of the recess is formed in a curved shape that gradually becomes deeper toward the bottom, and at least the elastic layer is bonded to the end of the recess via a base agent. The ball bat as set forth in claim 1. A display forming step for applying a character / decoration display to the bottom surface of the concave portion in which the hitting portion surface of the bat main body is recessed over the entire circumference;
A base layer forming step of applying a base agent to the concave portion of the hitting portion on which the character / decorative display is applied;
In the striking part of the bat body in a vertical position where the bat center axis is substantially vertical, a split mold having an inner peripheral surface formed in the surface shape of the striking part is placed in a surrounding state to form a mold, A mold installation process for forming a filling space between the mold and the mold;
An elastic layer filling step of filling the filling space without gaps from the lower part of the space to the upper part by pouring an elastic material having transparency in a fluid state through an injection path communicating with the upper end of the space;
A deaeration process for naturally flowing out air bubbles mixed in the elastic material by filling from the injection path;
A method for forming a ball game bat, comprising a mold removal step of waiting for the filled elastic material to harden and then removing the bat body from the mold to complete a ball game bat in which an elastic layer is integrally formed at a hitting portion.

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