| 摘要 |
In a machine for cutting a slit trench, a plow member that projects downwardly into the ground is caused to move in an orbital cutting path by means of a rotary eccentric drive shaft that is connected with an above ground portion of the plow assembly at a first selected point of attachment and restraining means that is connected to the above ground portion of the plow assembly at a second selected point of attachment, the plow assembly being both supported and driven by said eccentric shaft and said restraining means, and being characterized in that the restraining means comprises a link extending transversely of the plow assembly at said second point of attachment. The link is pivotally mounted at one end of the machine frame and is pivotally connected at its other end to the plow assembly at said second point of attachment, thereby to limit the transverse movement of said second point, i.e., in the direction of the link, but without impairing the longitudinal movement of said second point, thereby compelling the lower end of the plow to move in an elliptical orbital path. As an alternative, producing essentially the same results, the link may be replaced by an oscillatory eccentric idler shaft.
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