ENERGY ABSORBING BALL
An energy absorbing ball has a spherical resilient shell having a smooth inner surface and a smooth outer surface. A fill material is introduced into the shell via a fill opening in the shell. The fill material includes a liquid and a solid particulate having a density greater than the liquid, and with the fill material substantially entirely filling the shell. A plug in the fill opening seals the fill material within the shell, optionally with a recess over the plug. The smooth inside and outside surfaces of the she are spherical and free of any projections or obstructions.
1 . An energy absorbing ball, comprising:
a spherical resilient shell having a smooth inner surface and a smooth outer surface;
a hollow fill stem projecting radially inward from the smooth inner surface, the hollow fill stem having a fill opening extending from the smooth outer surface to an interior cavity of the spherical resilient shell;
a fill material within the interior cavity, the fill material comprising a liquid and a solid particulate having a density greater than the liquid, and with the fill material substantially entirely filling the shell; and
a plug in the hollow fill stem and obstructing the fill opening to seal the fill material within the interior cavity,
wherein the plug is disposed below the smooth outer surface such that an empty recess is formed below the smooth outer surface to a top portion of the plug.
2 . The ball of claim 1 with the fill material sealed within the shell only by the plug.
3 . The ball of claim 1 with the ball containing substantially no air or gas.
4 . The ball of claim 1 with the shell having a uniform wall thickness generally of about 2-4 millimeters.
5 . The ball of claim 4 with the shell having an outer diameter of 6-8 cm.
6 . The ball of claim 5 with the smooth inner surface of the shell free of any projections or obstructions other than the hollow fill stem.
7 . The ball of claim 6 with the liquid comprising oil and the particulate comprising iron sand.
8 . The ball of claim 6 with the particulate comprising metal filings, sand, metal beads or glass beads.
9 . The ball of claim 8 with the ball weighing 375 to 475 grams.
10 . The ball of claim 1 , wherein:
the spherical resilient shell is formed of rubber or plastic, the shell having a uniform wall thickness of 2-4 millimeters and an outer diameter of 6-8 cm;
the hollow fill stem is molded into the shell; and
the liquid of the fill material is oil and the particulate of the fill material has a density greater than the oil.
11 . The ball of claim 10 with the smooth inner surface of the shell free of any projections or obstructions other than the hollow fill stem.
12 . The ball of claim 11 with the ball weighing 375 to 475 grams.
13 . The ball of claim 11 with the particulate comprising 60 to 90% by weight of the fill material.
14 . The ball of claim 1 , wherein no sealing material is disposed on the plug.