| 摘要 |
In an inflatable ball, a substance is conveyed within its inner chamber which sticks to the inner surface subtending a small portion of the entirety of that inner surface. A rubber based catalyst is a particularly suitable substance because, when cured, it remains soft and pliable, enhancing its ability to remain adhered to the inner surface of an inflatable ball and to conform to the shape of that surface whether or not the ball is inflated. A heavy substance such as lead shot or stainless steel balls can be embedded into the liquid material prior to curing to increase the weight. Any substance embedded into the liquid material is introduced through the valve and port of the inflatable ball. With the center of gravity of the ball permanently altered, the ball has a tendency to rest in a position with the weighted material therewithin facing the ground surface on which the ball sits, and the ball has a tendency to stay in that position or to return to that position when an attempt is made to roll it in any direction away from that position. If a user succeeds in rolling the ball to a position where the portion of the inner surface engaging the weighted material rises to the top of the ball as it is rolled, when the ball is let go, it will move in an erratic way.
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