Abstract: When a tree stump has been split into several parts by a chopping action, the invention provides a gripping, shaking and cutting unit rigidly connected to the end of a vehicle-carried rotatable crane boom, having an adjustable effective length, for pulling out the stump parts along with their roots one by one from the earth in a direction substantially corresponding to the extension of the roots, and then shaking and cutting the stump parts.

Abstract: 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.

Abstract: A crane jib includes a support, a base arm pivoted in the support, and a jib lever pivotally connected to the base arm. The jib lever supports at its free end a work tool and is oscillated on its support by two hydraulic jacks, the first of the jacks is placed at a point from the journal place of the base arm, while the second jack is placed adjacent the jib lever. The second hydraulic jack has its line of action approximately parallel to a line through the bearing points of the base arm, while its lower bearing point is disposed at a lower level than the bearing place of the base arm.