| 摘要 |
PROBLEM TO BE SOLVED: To suppress vibrations transmitted from a casing pipe to a suspension member, and a noise accompanied by the vibrations, and to efficiently generate vertical vibrations on the casing pipe. SOLUTION: A pair of Uras (R) vibrators 11 are arranged on the outer part of the casing pipe 9 which is filled with sand. The pair of Uras (R) vibrators 11 are arranged in a non-connected state. Each of the Uras (R) vibrators 11 may be rotated and driven in the mutually opposite directions, and the number of rotations is freely changeable by an inverter control. Eight air springs 12 are provided between the casing pipe 9 and the suspension member 5. The air springs 12 are arranged at four positions on both of upper and lower surfaces of a vertically movable plate 30 to enhance the vibration absorbing action. COPYRIGHT: (C)2006,JPO&NCIPI
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