US Patent 7490912 Round shaft chisel

A round shaft chisel with a clamping sleeve, wherein the round shaft chisel has a chisel head and a chisel shaft rotatably maintained in the clamping sleeve. A pivot bearing is between an inner contour of the clamping sleeve and a shaft contour of the chisel shaft so that a center longitudinal axis of the round shaft chisel is pivotably seated with respect to a center longitudinal axis of the clamping sleeve. As a result of the induced tumbling motion of the round shaft chisel within the clamping sleeve 30, improved dirt removal can be assured during operations. The improved rolling action results in reduced wear between the clamping sleeve and the chisel shaft, which has advantageous results regarding the service life.