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US 4,729,746 AGranted
Buoy having excellent resistance against external pressure
AssigneesThe Yokohama Rubber Co., Ltd., Japan Drilling Co., Ltd.
InventorEiji Takemae
Life of this patent
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Abstract
Disclosed is a buoy which comprises a high density polyethylene foam as a buoyant member, and an outer skin covering the surface of the foam. The buoy has excellent resistance against external force and the loss of the buoyancy by the reduction of the volume is minimized.
Claims1
A buoy of the type, the volume of which varies depending upon the external pressure and which has excellent resistance against external pressure, comprising:
- a high density polyethylene foam as a buoyant member and;
- an outer skin covering the surface of the foam;
- said polyethylene foam having an expansion ratio of 10 to 40 and made from a high density polyethylene having a specific gravity of 0.945 to 0.965 and a heat distortion temperature of 60.degree. to 82.degree. C.
Dependencies are inferred from the claim text.