| 摘要 |
At the end of a vehicle-carried crane arm a vertically extending frame is supported which at its lower end carries a movable split head with spreadable chopping blades. A ram raisable to the top of the frame drives, when released, by the impact on the split head the blades into the center of a tree stump that is to be extracted from the earth. Then the blades are spread to break the stump into separate portions which are easily individually removable in a direction substantially following the extension of the roots. |
