Patent ID: 8291992

Claim:
A mobile soil working device comprising a machine frame ( 23 ), a drive comprising a pushrod ( 5 ), a guide element ( 4 ) movably guided at the machine frame ( 23 ), the guide element being provided for at least one penetration tool ( 3 ) adapted to be driven into the soil and to be pulled therefrom, a tool holder ( 2 ) for the penetration tool ( 3 ), which tool holder is supported about a first pivot axis ( 40 ) in the guide element ( 4 ) movable up and down by the drive via the pushrod ( 5 ), such that the penetration tool ( 3 ) can be pivoted against a spring force while in the soil, wherein the pushrod ( 5 ′, 5 ″) is compressible against a spring force, it being possible for the at least one penetration tool ( 3 ) to penetrate into the soil, given a normal soil resistance, and for the penetration tool ( 3 ) to deflect, when the soil resistance is substantially higher than a normal soil resistance, and the drive is adapted for up and down movement, and between the tool holder and the guide element a torsion element is provided coaxially with the first pivot axis, which torsion element, under a force effect on the at least one penetration tool, allows the tool holder to pivot relative to the guide element and, when the force effect ceases, exerts a restoring moment on the tool holder so that the penetration tool pivots back to a home position after having been pulled from the soil.