To protect a valve function by mounting a tight cap consisting of natural rubber, a synthetic rubber or a thermoplastic resin inside of an air injecting needle insertion hole opened at an air injecting valve so as to prevent the entering of foreign matters such as sand, soil to keep the airtightness of filled compressed air.
In order to prevent the entering of the foreign matters, a cylindrical tight cap 9 made of natural rubber or the synthetic rubber is mounted to the needle insertion hole 6. This cap 9 consists of a base part 9a and a head part 9b. The part 9a of the cap 9 is formed to be a little larger than the aperture of the hole 6 to improve adhesion with the hole 6. As the part 9b of the cap 9 is formed to be a little larger than the outer diameter of a mail valve 3 and restrained to a recess formed on the outer tip of the valve 3 to be housed the surface of a ball main body, the cap 9 never comes into direct contact with a user's body at the time of using a ball.
KIKUMOTO YOSHITAKA
NINOMIYA NORIKAZU
