Producing method of ball for ball game

Abstract

A producing method of ball for ball game including a ball cover and a bladder is disclosed. The method includes steps of (a) inflating a bladder and providing a web layer by coating at least a thread on an outer surface of the bladder thereafter, (b) fabricating a plurality of panels in a predetermined shape, (c) sewing the plurality of panels edge to edge together excluding a portion thereof by a sewing machine to form a ball cover including an inlet opening, (d) inserting the bladder obtained at step (a) into the ball cover obtained at step (c) through the inlet opening, (e) sewing the inlet opening of the ball cover, and (j) inflating the ball for ball game to a predetermined pressure within a shaping mold.

Description

BRIEF EXPLANATION OF THE DRAWING

FIG. 1 is a graph showing the relationship between the internal pressure and deformation amount (distance) of a ball used for calculating compression hardness, compression energy and compression restoring property of a ball.

BEST MODE FOR CARRYING OUT THE INVENTION

A producing method of ball for ball game according to the present invention includes following steps:

Step I: Inflate a bladder provided with a valve stem.

Step II: Coat the bladder with at least an elongated thread.

Step III: Form a reinforced bladder by winding the reinforcing thread evenly around an outer surface of the bladder until the bladder is embraced by a web layer.

Step IV: Cut a ball cover material, for example natural leather, synthetic leather including a sponge material made of forming polyurethane or polyvinyl chloride or laminated material, into a predetermined number of panels in a predetermined shape. At step IV, 12 pieces of pentagonal panels and 20 pieces of hexagonal panels are cut for a soccer ball, and 18 pieces of panels in two kinds of rectangular shape are cut for a volleyball.

Step V: Sew the panels edge to edge together by a sewing machine to form a ball cover which has a valve hole provided thereon. A section of the panels are not sewn together to form an inlet opening at this step.

Step VI: Turn the ball cover right side out and insert the reinforced bladder into the ball cover through the inlet opening.

Step VII: Align and adhere the valve stem of the bladder with the valve hole of the ball cover.

Step VIII: Semi-inflate the bladder to make sure that the bladder would prop against the ball cover.

Step IX: Sew the inlet opening of the ball cover together to form the ball for ball game.

Step X: Fully inflate the ball for ball game to more than a standard pressure within a shaping mold to ensure a permanent structure and shape of the bladder and ball cover.

In the same manner as in the sportsball disclosed in U.S. Pat. No. 5,772,545, a primary stress supporting portion of the ball for ball game of the present invention is the reinforced bladder having flexibility and impact resistance.

Accordingly, the ball for ball game is advantageous in that the ball cover enables not only reducing the impact of a header but also reducing the impact of kicking a ball with a foot.

In the ball for ball game according to the present invention, the portion which supports the stress and bears the impact is also the reinforced bladder. Therefore, expensive leather panels and laminated material of the ball cover may be formed thinner in order to decrease costs.

The present invention is further explained by way of examples. However, the present invention is not limited to such examples.

EXAMPLE

Five samples of the ball for ball game were manufactured in accordance with the producing method of the present invention, and compression hardness (LC), compression energy (WC) and compression restoring property (RC) were calculated by utilizing a handy compression testing machine. With respect to the compression hardness (LC), compression energy (WC) and compression restoring property (RC), LC is obtained by dividing the sum of the areas of region a and region b by the area of a triangle ABC in the graph of FIG. 1, WC is obtained by summing the areas of region a and region b in the graph of FIG. 1, and RC is obtained by dividing the area of region b in the graph of FIG. 1 by the sum of the areas of region a and region b and multiplying by 100. With respect to LC it is determined that the hardness increases as the value approaches to 1, with respect to WC it is determined that the ball is likely to be compressed with the increase in value, and with respect to RC it is determined that there is increased restoring property as the value approaches to 100%.

The calculated result is shown in Table 1.

COMPARATIVE EXAMPLE

Five samples were manufactured in accordance with the manufacturing method disclosed in U.S. Pat. No. 5,772,545, and compression hardness (LC), compression energy (WC) and compression restoring property (RC) were calculated by utilizing a handy compression testing machine in the same manner as the above-described example.

The calculated result is shown in Table 1.

TABLE 1
			Data obtained by
Measuring		Data obtained by	measurement with web
item	Measuring method	measurement with ball	bladder (average of n = 5)
Rebound	Measure the height of rebound	Example: 143 cm	Example: 154 cm
	with 2 m free fall	Comparative Example: 138 cm	Comparative Example: 148 cm
Impact value	Measure impact value when ball	Example: 55.9	Example: 43.3
(kgf)	hits the ground with 1 m free fall:	Comparative Example: 57.5	Comparative Example: 45.6
	An index indicating softness when
	ball hits the ground (softer as the
	value decreases)
Compression	Compression energy when load of	Example: 8.2
energy	5 kgf is applied with 2 cm2	Comparative Example: 7.9
(gfcm/cm2)	pressurized area (work load):
	An index indicating softness when
	ball is pressed with finger (softer
	as the value increases)
Compression	Increased restoring property as the	Example: 83.2
restoring	value approaches to 100%	Comparative Example: 80.2
property
(gfcm/cm2)

Claims

1. A producing method of ball for ball game, comprising steps of: (a) inflating a bladder and providing a web layer by coating at least a thread on an outer surface of the bladder thereafter;(b) fabricating a plurality of panels in a predetermined shape;(c) sewing the plurality of panels edge to edge together excluding a portion thereof by a sewing machine to form a ball cover including an inlet opening;(d) inserting the bladder obtained at step (a) into the ball cover obtained at step (c) through the inlet opening;(e) sewing the inlet opening of the ball cover; and(j) inflating the ball for ball game to a predetermined pressure within a shaping mold.

2. A producing method of ball for ball game, comprising steps of: (k) inflating a bladder having a valve stem thereon;(l) coating the bladder with at least an elongated thread;(m) winding the reinforcing thread evenly around an outer surface of the bladder until the bladder is embraced by a web layer of the reinforcing thread;(n) cutting a ball cover material into a plurality of panels in a predetermined shape;(o) sewing the plurality of panels edge to edge together by a sewing machine to form a ball cover having a valve hole provided thereon and forming an inlet opening by not sewing a portion of the plurality of panels;(p) inserting the bladder into the ball cover through the inlet opening;(q) aligning the valve stem of the bladder with the valve hole of the ball cover to apply an adhesive agent;(r) inflating the bladder at a pressure lower than a predetermined pressure;(s) sewing the inlet opening of the ball cover together by hand; and(t) inflating the ball for ball game to more than a standard pressure within a shaping mold.