JPH0536210B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention provides a dimple provided on the circumferential surface of a golf ball that is not influenced in any way by the mating surfaces of an upper mold and a lower mold having substantially hemispherical depressions. The present invention relates to a golf ball molding die that can be formed without using a golf ball.

(Prior art) Dimples are generally formed on the circumferential surface of a golf ball by injection molding a synthetic resin material into a mold that is divided into upper and lower or left and right halves, and by molding a ball with an unmolded outer skin in advance. It is carried out by press-molding under heat using a mold having a similar configuration.

By the way, a normal molding die used for such molding consists of an upper mold 1 and a lower mold 2 (including cases of left and right molds), as illustrated in FIG. 2, and these upper and lower molds 1 and 2 are Each has a hemispherical depression 3 and a plurality of protrusions 4 formed on the surface of the depression to provide dimples on the circumferential surface of the golf ball.

Here, the mating surfaces 1a and 2a of the upper and lower dies 1 and 2 are as follows:
They have flat surfaces aligned with the equatorial plane of the golf ball to be molded, and their mating surface positions are similar to the dimples of the golf ball 5 to be molded, as shown in cross-section in FIG. 6, the part of the molding burr 7 generated between the mating surfaces 1a and 2a that exists inside the dimple cannot be sufficiently polished away.
Generally, the double-sided mating surfaces 1a and 2a are selected to be located between rows of protrusions arranged in a row in the circumferential direction of the recess 3 along the mating surfaces 1a and 2a, and this prevents the occurrence of This makes it possible to completely remove molding burrs by polishing.

(Problems to be Solved by the Invention) However, according to such a conventional molding die, molding burrs generated between the mating surfaces 1a and 2a of the upper and lower molds 1 and 2 during molding are caused by the molding burrs generated between the mating surfaces 1a and 2a of the upper and lower molds 1 and 2, respectively.
In order to increase the distance between the protrusion rows provided adjacent to each other, as shown in FIG.
In the part corresponding to the mating surfaces 1a and 2a of 2,
The spacing d between the dimple rows formed on the circumferential surface of the golf ball 5 is larger than the spacing between other dimple rows by a distance corresponding to the burr thickness, and the spacing d
However, there was a problem in that this impairs the appearance of the golf ball 5, and also contributes to a reduction in the flight distance of the ball and to the ball becoming oily.

For example, as shown in FIG. There has also been a proposal to prevent the deterioration of the appearance of the golf ball 5 by providing the book band-like land portion 8 in a restrictive manner. This has the problem of impairing the excellent aerodynamic properties of the golf ball 5 which are provided as uniformly as possible over the circumferential surface.

The present invention advantageously solves this problem of the prior art by making the spacing between the rows of dimples of the golf ball provided by the mating surfaces of the upper and lower molds and the corresponding portions almost or completely the same as the spacing in other portions. The present invention provides a mold for molding a golf ball.

(Means for Solving the Problems) The molding die of the present invention has an approximately hemispherical recess, and an upper mold and a lower mold each having a plurality of protrusions on the surface of the recess at approximately equal intervals. The mating surface is formed into an uneven shape between protrusions provided along the mating surface.

(Function) In this mold, the mating surfaces of the upper and lower molds pass between the plurality of protrusions provided on the recessed surfaces to form an uneven shape. Molding burrs that occur on the surface of the ball also avoid the dimples in the dimple rows that are arranged at regular intervals on the circumferential surface of the ball, and are generated on the land between the dimples. In the portion corresponding to , a wide band-like land portion unlike in the prior art does not occur between the dimple rows of the ball.

That is, here, by effectively utilizing the land areas existing between the dimples in the dimple rows provided at appropriate intervals on the circumferential surface of the golf ball and generating molding burrs there, The spacing between the dimple rows in the corresponding part can be made completely or almost the same as that in other parts.

Moreover, according to this molding die, molding burrs are
This occurs in the land area between the dimples, which are located at substantially equal intervals. Therefore, there is no risk of producing a different polished state from that of other dimples. In other words, if a molding burr occurs at a position corresponding to the outline of the dimple, polishing the entire golf ball evenly to completely remove the molding burr will remove the molding burr. Under the condition that the normal outline of the part of the dimple that caused the molding burr disappears and the normal outline of the part of the dimple that causes the molding burr appears, the normal outline of the part of the dimple that does not cause the molding burr and the regular outline of other dimples This is due to the fact that the line has already undergone a considerable amount of polishing, and therefore the amount of polishing of the contour line edged by the forming burr is less than that of the other contour line portions of the dimple. In addition to being forced to distort the dimple, it also causes a difference in size and shape from the dimple that was originally surrounded by a regular contour line. , the aerodynamic properties of the golf ball will be impaired.

(Example) The present invention will be explained below based on illustrated examples.

FIG. 1 is a partial front view showing the main part of an embodiment of the present invention on an enlarged scale.
and the respective mating surfaces 11 and 12 of the lower mold 2,
The protrusions 4 of the protrusion row provided along the mating surfaces 11 and 12 are avoided and are formed in an uneven shape upward and downward.

That is, in the example shown in FIG. 1a, the mating surface 1
1 and 12 are formed in a zigzag shape in the vertical direction and extend in the circumferential direction passing between the respective protrusions 4 spaced at approximately equal intervals, and in the example shown in FIG. 4, and in the example shown in FIG. 1c, both mating surfaces 1
1 and 12 are repeatedly formed into a trapezoidal shape.

In any of these examples, the molding burrs generated between the mating surfaces 11 and 12 during molding of the golf ball 5 are present between the dimples 6 and 6 arranged at a predetermined interval. Since the molding burr does not change the distance between the dimples 6, 6, the dimple row on the circumferential surface of the ball and the distance between the dimples 6, 6 are always kept at a predetermined distance at any part of the circumference. It becomes a constant value. Moreover, here, molding burrs are generated in the land portion between the dimples 6, 6, so each dimple 6 is inevitably polished to remove the molding burrs.
The amount of polishing of the contour line is approximately the same for all dimples 6, and therefore, the relative relationships in shape, size, etc. between the dimples remain constant as expected before and after polishing. The aerodynamic properties of the golf ball are not compromised by polishing.

(Effects of the Invention) Therefore, according to the molding die of the present invention, it is possible to reliably prevent the formation of wide band-like land portions between the dimple rows of the golf ball in the portion corresponding to the mating surfaces of the upper and lower molds. be able to. Moreover, here,
When removing molding burrs by polishing, the contour lines of all dimples are polished almost uniformly, so that the aerodynamic characteristics of the golf ball are not impaired by the polishing.

[Brief explanation of drawings]

Fig. 1 is a partial front view showing an embodiment of the present invention with main parts enlarged, Fig. 2 is a perspective view illustrating a conventional molding die, and Fig. 3 shows the state of occurrence of molding burrs in the dimple. FIG. 4 is a partial front view showing the spacing between dimple rows provided by the prior art, and FIG. 5 is a front view showing the proposed technology. 1... Upper mold, 2... Lower mold, 3... Hollow, 4...
Projections, 11, 12... mating surfaces.

Claims (1)

[Scope of Claims] 1. A top having a substantially hemispherical depression and a plurality of protrusions formed on the surface of each depression to form dimples on the circumferential surface of the golf ball, at substantially equal intervals. A golf ball mold comprising a mold and a lower mold, wherein the mating surfaces of the upper and lower molds are formed into an uneven shape by passing between the protrusions provided along the mating surfaces. .