| 摘要 |
In a railway track ballast tamping device, a tamping unit is carried for vertical adjustment by a support mounted on the frame structure of a vehicle and comprises at least one pair of jointly-operating tamping tools crossing each other. The arm of these tools are adapted to pivot on opposite eccentric cranks formed on an eccentric shaft rotatably mounted in a bearing rigidly fastened to the support; the upper ends of the arms, opposite the pick-forming thereof, are each pivotally connected to a hydraulic cylinder inclined not in excess of 30 DEG to the vertical; the planes passing through the axis of rotation on the eccentric shaft and the center of the opposite eccentric cranks thereof form between them an angle of 40 DEG to 80 DEG in order to warrant a symmetrical, synchronous oscillatory motion of the packers carried by the lower ends of the picks. To prevent the transmission of detrimental vibration to the support during the rotation of the eccentric shaft, there are provided, in addition to out-of-balance weight carried by a flywheel rigid with the eccentric shaft, balance weights fastened to the hydraulic cylinders and disposed above the level of the pivotal connections between these cylinders and the support. Furthermore, the tamping tools of a pair disposed on the same side of a tie have their upper ends rigidly interconnected.
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