JPS62152485A - Production of hard ball for baseball - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method of manufacturing a hardball baseball ball.

More specifically, the present invention relates to a method of manufacturing this type of ball having a double structure made of synthetic resin.

[Prior Art] As is well known, currently officially recognized hardball baseballs are made of animal skin sewn together on the side. However, after such balls are used for a certain amount of time, the seams tend to rupture, and the undone balls must be discarded or re-sewn and reused. In any case, the cost and effort required for replenishing or repairing balls is a heavy burden on those involved.

In order to solve the above problem, the applicant has already applied for the
No. 192849 (Utility Model Application No. 58-98960) proposed a ball as shown in the partially cutaway view of FIG. This ball 10 has a double structure consisting of a core 12 and sides 16 in order to obtain a predetermined repulsion force, weight, etc. and surface feel.The core 12 is made of hard synthetic resin, and the sides 16 are made of a hard synthetic resin. Molded from soft synthetic resin. The core 12 is provided with a plurality of corners 14 for a centering effect when molding the side 16 and for fixing the connection between the core 12 and the side 16, and the side 16 is provided with a hammer-like unevenness 18. is formed.

[Problems to be Solved by the Invention] In the previously proposed ball, however, if excessive force is applied during use, cracks will occur from the vicinity of the corner 14 of the core 12 to the side 16, and cracks will occur. Concomitantly core 12 and side 16
There was a problem in that it could become unusable due to separation.

The present invention has been made based on this point of view, and eliminates the drawbacks of the above-mentioned prior art, and while taking advantage of the advantages of the double structure, cracks are less likely to occur on the sides and separation between the core and the sides is less likely to occur. The purpose of the present invention is to provide a manufacturing method for a ball for hardball baseball.

[Means for Solving the Problems] In order to achieve the above object, the present invention mainly focuses on the centering of the core and the connection and fixation between the core and the sides. In the method of the present invention, first, a thin wire member longer than the diameter of the final product ball is placed in a core mold coated with a mold release agent. Then, the core mold is closed, and the molten core synthetic resin is poured into it to form a core in which the thin wire member protrudes to the outside. Thereafter, the molded core is removed from the mold, and the mold release agent adhering to its surface is washed off.

The molded core is then transferred to a side mold, and the side mold has a seating part for the thin wire member, and when the core with the thin wire member molded in the above process is placed in the seating part, , the core is formed so as to be located at the center of the formwork. A molded core is placed inside the side mold, the side mold is closed, and a molten side synthetic resin is poured into the mold, and the core is covered with the side to form a ball with a thin wire member protruding outside. mold. Then, the molded ball is taken out of the mold and the @ wire member is pulled out from the ball to complete the product ball.

[Function] According to the method for manufacturing a hardball baseball having the above structure, centering of the core within the side mold can be performed via a thin wire member. In addition, bonding between the core and the sides is possible by washing off the mold release agent on the core surface at an intermediate stage, and a microscopic layer is formed by melting and bonding the resins at the interface between the core and the sides. Become.

[Example 2] FIG. 2 is a partially cutaway view showing a ball manufactured by the method of the present invention. This ball 20 also has a double structure consisting of a core 22 and a side 26, similar to the already proposed ball 10 shown in FIG. It is molded from. core 22 and f
The composition, size, etc. of the material of f1l1213 are determined by comprehensively considering the predetermined repulsion force, M feel, surface feel, etc. In this embodiment, the core 22 is smaller and the sides 26 are thicker compared to the previously proposed ball 10, and the composition of the materials of both members 22, 26 is therefore somewhat different from the previously proposed ball 10. It has become a thing. Also core 2
No corners are formed in the core 22 and the side 26, and the core 22 and the side 26 are connected and fixed at the interface 24 between the two through a microscopic layer in which the resins are melted and bonded to each other. In addition, seam-like unevenness 18 is formed on the side 26 similarly to the previously proposed ball 10.

FIGS. 1a to 1d are schematic diagrams that do not show the method for manufacturing the ball according to the present invention in a step-by-step manner.

In FIG. 1a, 30 is a formwork for the core (only half of which is shown), and this formwork 30 has a 90° angle around the mold 32.
Four grooves 34 are bored at equal intervals. The groove 34 functions as a seating portion for an II wire member 36, which will be described later.
The Rn product ball is formed to protrude slightly outward from the diameter of the product ball. In the present invention, first, these W2
As shown in B5, two thin wire members 3 made of piano wire, etc.
1 in a cross shape of 6! hand over. Both wire braid members 36 extend fully from end to end of groove 34, so that both wire braid members are somewhat longer than the diameter of the R cotton product ball. Further, the thin wire members 36 intersect at approximately the center of the core sphere. Note that a mold release agent is applied to the inner surface of the mold 32 of the mold frame 30 in advance.

Next, the core mold 30 is closed, and the molten core synthetic resin is poured into it to form the core 22 in which the thin wire members 36 radially project outward as shown in FIG. 1b. The molded core 22 is then taken out from the mold 30, and the mold release agent adhering to the surface of the core 22 from the mold 30 during molding is washed off using kerosene or the like. As will be described later, this operation is important in forming a layer in which the resins are fused together at the interface 24 between the core 22 and the side 26, and therefore it is desirable to perform this operation carefully.

In FIG. 1C, 40 is a side formwork (only half of which is shown), and this formwork 40 also has 90
Four grooves 44 are bored at equal intervals of '. The groove 44 functions as a seating portion for the thin wire member 36, and is formed to extend to the same diameter as the groove 34 of the mold 30, that is, to extend slightly further outward than the diameter of the final product ball. These grooves 44 are such that when the thin wire member 36 of the core 22 with the thin wire member 36 molded in the above process is placed therein, the core 22 is located at the center of the formwork 40. Further, a mold release agent is also applied to the inner surface of the mold 42 of the mold frame 40 in advance.

After the thin wire member 36 is seated in the groove 44 in the manner described above and the core 22 is placed at the center within the side formwork 40, the side formwork 40 is closed, and the molten side synthetic material is poured into the side formwork 40. The core 22 is coated on the sides 26 by pouring resin. During molding of this side 26, since the mold release agent on the surface of the core 22 has been sufficiently washed off as described above, the surface of the core 22 is also microscopically melted by the heat of the molten synthetic resin for the side. At the interface 24 between the core 22 and the side 26, a layer is formed in which the resins are fused together.

By forming this microscopic fusion bonding layer, the core 22 and the side 2
A strong bond with 6 is obtained.

The resulting ball 20 taken out from the side formwork 40 has a thin wire member 36 projecting radially to the outside as shown in FIG. Final product ball 2 shown in Figure 2
0 is completed.

[Effects of the Invention] According to the method for manufacturing a hardball baseball according to the present invention, since the core does not have a protrusion such as a corner that weakens the strength of the side, the ball does not easily break due to cracks on the side. There is no. Furthermore, since the core and the sides are connected and fixed with their resins melted and bonded to each other at the interface between the two, separation between the core and the sides does not easily occur.

[Brief explanation of drawings]

Figures 1a to 1d are schematic diagrams showing the method of manufacturing a ball according to the present invention step by step, Figure 2 is a partially cutaway view showing a ball manufactured by the method of the present invention, and Figure 3 is a diagram showing a ball manufactured by the method of the present invention. FIG.

Claims (1)

[Claims] In a method for producing a hardball baseball comprising a core made of hard synthetic resin located at the center and a side made of synthetic resin softer than the core covering the core, the core is coated with a release agent. The process of placing a thin wire member longer than the diameter of the final product ball in the core mold, closing the core mold, and pouring the molten core synthetic resin into it, causing the thin wire member to protrude outside. a step of molding the core; a step of taking out the molded core from the mold and washing off mold release agent adhering to its surface; and a seating portion for the thin wire member, and the fine wire member molded in the above step on the seating portion. placing the core in a side formwork formed such that the core is located at the center of the formwork; and closing the side formwork and placing the molten material therein. A step of pouring synthetic resin for the sides and molding a ball with a thin wire member protruding outward by covering the core with the side, and a step of taking out the molded ball from the mold and extracting the thin wire member from the ball. A method for manufacturing a hardball baseball, characterized by: