JP2004105775A - Head cap of metal baseball bat and designing method for metal baseball bat - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To adjust weight and balance of a metal baseball bat and reduce affection toward hitting sound. <P>SOLUTION: A head cap is attached on a tip end part of a metal baseball bat body. The head cap 1 is composed of a resin material or rubber material and loaded with weight adjusting material additives 1H, 1L having different specific gravities from the resin material or the rubber material. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a metal bat, particularly a head cap.

Conventionally, it is known that the weight, balance, moment of inertia, etc. of the metal bat can be adjusted without changing the flight characteristics (repulsion characteristics) etc. by fitting a disk to the tip of the metal bat. (Patent Document 1).
Japanese Utility Model Publication No. 60-7096

However, with this conventional technology, a big change is given to the striking sound peculiar to metal bats. In other words, unlike a wooden bat, a metal bat emits a specific pleasant sound at the time of striking regardless of whether the ball is caught by the core, but when the disc is fitted, this striking sound cannot be predicted. Change. Therefore, for example, a pleasant sound at the time of hitting may not be obtained.

Therefore, the main object of the present invention is to adjust the weight and balance of the metal bat and reduce the influence on the hitting sound.

In order to achieve the above object, according to the present invention, in a head cap attached to the tip of a metal bat body, the resin material or rubber material constituting the head cap has a specific gravity different from that of the resin material or rubber material. A weight adjusting material is added.

According to the present invention, the weight of the metal bat, the balance of the weight, and the moment of inertia around the grip end can be easily changed by changing the weight of the head cap. It is possible to easily set a bat that matches the batter's physical strength while keeping it the same.
In particular, unlike attaching a foreign object such as a disk to the tip of a metal bat, it only changes the weight of the head cap, so the impact sound does not change so much that it cannot be predicted. There is no fear that you will not be able to obtain a pleasant sound.

Also, in the invention of claim 1, unlike the case where a disk is mounted, the number of parts does not increase, so there is almost no risk of increasing the cost.

On the other hand, in the invention of claim 3, since the weight adjusting portion is provided in the central portion in the radial direction of the head cap, the flat rigidity of the head cap is difficult to change. Becomes smaller.

Further, in the invention of claim 4, since the weight mounting recess is provided in the center portion of the head cap, the weight of the metal bat can be changed very easily depending on whether or not the weight is mounted, Similar to the third aspect of the invention, the influence on the hitting sound is reduced.

The metal bat design method of the present invention changes the weight of the metal bat, the balance of the weight, and the moment of inertia around the grip end by changing the weight of the head cap attached to the tip of the metal bat body. It is characterized by that.
The invention of the head cap embodied by this design method includes the following.

That is, according to the first aspect of the present invention, in the head cap attached to the tip of the metal bat body, the resin material or rubber is used as the resin material or rubber material constituting the head cap in FIGS. Weight adjusting materials 1H and 1L having different specific gravities from the materials are added.
In the present invention, the “weight adjusting material” refers to a fibrous material or a granular material having a particle size of 10 μm or more. This is because the powder having a particle diameter smaller than this value is added to a general head cap as a resin additive or a rubber compounding material, and is therefore distinguished from a general additive or the like.

A non-metallic material can be used as the weight adjusting material 1H having a specific gravity larger than that of the polymer (polyurethane resin, polyethylene resin, etc.) constituting the head cap 1 in FIG. 1B. Generally, tungsten, lead, brass, etc. Metal particles such as iron, stainless steel, and aluminum can be preferably used.
On the other hand, a foamed resin can be used as the weight adjusting material 1L having a small specific gravity in FIG.

Here, as the weight adjusting materials 1H and 1L, those which do not easily affect the flat rigidity of the head cap are preferable.
That is, although the head cap 1 has a function of absorbing the impact sound, as shown in FIG. 2, the flat rigidity of the head cap and the peak frequency of the impact sound are in a substantially proportional relationship. This is because the impact sound changes greatly when the flat rigidity changes greatly. The “peak frequency” refers to a frequency having the highest sound pressure among the hitting sounds. Further, “flat rigidity” refers to the rigidity of the head cap 1 when a load is applied to the head cap 1 of FIG.

In order to make it difficult to affect the flat rigidity, lead or brass particles having a small Young's modulus and a large specific gravity are preferable among the metal particles, and the particle size is preferably 100 μm to 2 mm. This is because a metal particle or a fibrous material having a small particle size acts as an aggregate and changes the flat rigidity.

Further, in order to change the weight and balance sufficiently by the head cap 1, it is necessary to make it lighter or heavier than the weight of the conventional head cap (previously 43g to 55g). It is preferable to be 58 g or more.

As shown in FIG. 1A, the head cap 1 has a cylindrical portion 10 fitted to the inner peripheral surface of the metal bat and a closing portion 11 that closes the opening at the tip of the metal bat. Is formed.

The head cap according to the second aspect of the present invention is a head cap mounted on the tip of a metal bat body, and the peripheral edge of the head cap 1 at the center in the radial direction of the head cap 1 shown in FIGS. The weight adjusting part 2 having a specific gravity different from that of the material of the part is provided.

As shown in FIGS. 3A, 3 </ b> B, and 3 </ b> C, the weight adjusting unit 2 may be integrally formed in the central portion in the radial direction of the head cap 1, but is shown in FIG. 4 or FIG. 5. As described above, the head cap 1 may be mounted after the head cap 1 is molded. In the second aspect of the present invention, the reason why the weight adjusting portion 2 is disposed in the central portion in the radial direction of the head cap 1 is to reduce the influence on the flat rigidity of the head cap 1. Here, the weight adjusting unit 2 may be a metal, but a resin or rubber containing metal particles, metal powder, or metal fiber is preferable because it has less influence on flat rigidity.

The head cap according to the third aspect of the present invention is provided with a weight mounting recess 3 at the radial center of the head cap 1 in FIGS. 4 and 5, and the weight mounting recess 3 is engaged with the weight. Engaging elements 3a and 3b are formed.

In the third invention, as the engaging elements 3a, 3b of the weight mounting recess 3, a female screw 3a is formed in the weight mounting recess 3 of FIG. 4, or the weight mounting recess of FIG. 3 can be formed by forming a recess 3b for engagement. Further, the third invention is included in the scope of the third invention regardless of whether or not the weight 4 of FIGS. 4 and 5 is mounted in the weight mounting recess 3. In other words, the weight mounting recess 3 is not mounted with the weight 4 and may be used as a head cap 1 for a light metal bat. On the other hand, by mounting the weight 4 in the weight mounting recess 3, the head cap 1 for a heavy metal bat is obtained. Note that the weight 4 preferably has the same composition (matrix) as the weight adjusting unit 2 described above, and constitutes the weight adjusting unit 2 when mounted in the weight mounting recess 3. Further, the weight 4 has a male screw 4a that is screwed into the female screw 3a of the weight mounting recess 3 in FIG. 4 and an engagement protrusion that engages with the engaging recess 3b in the weight mounting recess 3 in FIG. 4b is provided.

It is the perspective view and enlarged partial sectional view of the head cap which show one Embodiment of 1st invention. It is a graph which shows the relationship between the flat rigidity of a head cap, and the peak frequency of an impact sound. It is the perspective view and sectional drawing of a head cap which show one Embodiment of 2nd invention. It is a disassembled sectional view of the head cap which shows 1st Embodiment of 3rd invention. It is a disassembled sectional view of the head cap which shows 2nd Embodiment of 3rd invention.

Explanation of symbols

1: Head cap 1H, 1L: Weight adjustment material 2: Weight adjustment part 3: Recess for weight mounting 4: Weight

Claims (5)

In the head cap attached to the tip of the metal bat body,
A metal bat head cap, wherein a weight adjusting material having a specific gravity different from that of the resin material or rubber material is added to the resin material or rubber material constituting the head cap. The metal cap head cap according to claim 1, wherein the weight of the head cap is set to 40 g or less or 58 g or more. In the head cap attached to the tip of the metal bat body,
A metal bat head cap, wherein a weight adjusting portion having a specific gravity different from a material of a peripheral portion of the head cap is provided at a central portion in a radial direction of the head cap. In the head cap mounted on the tip of the metal bat main body, a weight mounting recess is provided in the central portion in the radial direction of the head cap, and the engagement element for engaging the weight in the weight mounting recess A metal bat head cap, characterized in that is formed. A method of designing a metal bat,
A method of designing a metal bat in which the weight of the metal bat, the balance of the weight, and the moment of inertia around the grip end are changed by changing the weight of the head cap attached to the tip of the metal bat body.

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