JPH07299170A - Manufacture of metal bat - Google Patents

Abstract

PURPOSE:To intensify a bouncing force of a ball hitting part while increasing the strength thereof by working a plain cylinder for a metal bat at a position where the ball hitting part is formed by swaging to reduce diameter by a specified value. CONSTITUTION:In this manufacturing method of a metal bat, a swaging is performed on one side of an aluminum cylinder 1 for a bat to form a grip side 6 of the bat, an aluminum reinforcing cylinder 3 is fitted inside a ball hitting part 2 and the ball hitting part 2 is reduced in diameter. For example, after the fitting of the reinforcing cylinder 3 with a outer diameter of 65mm inside the aluminum cylinder 1 with an outer diameter of 69mm, the aluminum cylinder 1 is reduced in diameter by a specified value by swaging down to 65mm in outer diameter. This working enables the putting of the internal wall 1a of the aluminum cylinder 1 tightly on the external wall of the reinforcing cylinder 3 thereby eliminating fear of movement of the reinforcing cylinder during the use. Then, a tip part 4 is closed and a grip end 5 is fixed to make a metal bat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a metal bat for the purpose of retaining strain in the hitting portion of a bat, enhancing strength and improving resilience.

[0002]

2. Description of the Related Art Conventionally, there has been known a technique of providing an interior or fitting a reinforcing pipe to the outside in order to reinforce the hitting portion of a metal bat (Japanese Patent Laid-Open No. 5-57042).

[0003]

The above-mentioned conventional reinforcing structure is
When a bat body and a reinforcement pipe are used while the bat is in use, when a thin-walled pipe is fitted and fixed to the outside of the hitting part and there is a possibility that it may give a foreign appearance and the deformation during processing is not sufficient. There is a problem that a gap is generated in the contacting part with.

[0004]

According to the present invention, the hitting portion of a bat material is reduced in diameter by swaging (1% to 10%).
By doing so, the above-mentioned conventional problems have been solved.

That is, the present invention is a method for manufacturing a metal bat, which is characterized in that the hitting portion forming position of the metal bat bare cylinder is reduced in diameter by a predetermined amount by swaging. Still another invention is a method of manufacturing a metal bat, characterized in that a reinforcing metal cylinder is fitted inside a ball striking portion of a metal bat blanket, and then the ball striking portion is swaged to reduce a diameter by a predetermined amount. is there.

Next, regarding the diameter reduction ratio in the present invention,
There is no best value, but 1% to 10% to achieve the purpose
% Is normal and 2% to 9% is a preferable range.

Although the preferable diameter reduction ratio differs depending on the structure (thickness, outer diameter, single cylinder or double cylinder), it is usually 2
The purpose can be achieved by reducing the diameter to 9% to 9%.

In the above description, there is a case where the reinforcing metal cylinder is fitted into the hitting portion and a case where the reinforcing metal cylinder is not fitted therein, but in any case, it is clear that the elastic force can be enhanced by the diameter reduction processing.

[0009]

According to the present invention, the hitting portion of the bat is reduced in diameter, so that the resilience at hitting can be improved and the portion can be reinforced.

[0010]

EXAMPLE A bat gripping side 6 is formed on one side of an aluminum cylinder 1 for bats by swaging, and then an aluminum reinforcing cylinder 3 is fitted inside the hitting portion 2 and then the portion is compressed. Diameter. For example, after the reinforcing cylinder 3 having an outer diameter of 65 mm is fitted inside the aluminum cylinder 1 having an outer diameter of 69 mm, the aluminum cylinder 1 is reduced in diameter by swaging until the outer diameter of the aluminum cylinder 1 becomes 65 mm. By this processing, the inner wall 1a of the aluminum cylinder 1 and the outer wall 3a of the reinforcing cylinder 3 are in close contact with each other, so that the reinforcing cylinder 3 does not move during use.

Next, the tip 4 is closed and the grip end 5
By fixing (welding) to each other, the bat of the present invention can be formed.

[0012]

According to the present invention, since the hitting portion is reduced in diameter, the resilience of the portion can be enhanced and the strength can be increased. The strength varies depending on the material and the presence or absence of the reinforcing cylinder, but when compared with the one not subjected to the diameter reduction processing, there is a second increase in the Rockwell B scale (HRB).

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of an embodiment of the present invention.

FIG. 2 is a front view in which a part of the bat barrel is also omitted.

FIG. 3 is a front view of the diameter reducing portion.

[Explanation of symbols]

 1 Aluminum tube 2 Hitting ball section 3 Reinforcing tube 4 Tip section 5 Grip end

Claims (3)

[Claims] 1. A method of manufacturing a metal bat, characterized in that a hitting portion forming position of a metal bat bare cylinder is reduced in diameter by a predetermined amount by swaging. 2. A method of manufacturing a metal bat, characterized in that a reinforcing metal tube is fitted inside the ball striking portion of the metal bat barrel, and the ball striking portion is swaged to reduce the diameter thereof by a predetermined amount. 3. The method for producing a metal bat according to claim 1, wherein the diameter reduction amount is 2 to 9% of the outer diameter.