对于具有切割头（1），所述凿（24）在有限行程岩石Schrämen（a）用一液压缸 - 活塞单元，轴向可滑动的诸如阀（18）合作，所以建议在缸体活塞单元间歇性地与压力介质 加压，使位（24），其在岩石接合过程中暴露在突如其来的力量。 在不与压力介质加压缸体活塞单元的相位，所述凿（24）被压入其初始位置。 该训练可满足液压和气动气缸 - 活塞装置，该气缸 - 活塞装置的作为在形成作为液压缸 - 活塞单元的阀的结构（18）是优选的，其在同一时间通过一个喷射喷嘴的压力流体的挤压（32） 允许工作面。

For Schrämen of rock with a cutting head (1), the chisel (24) over a limited stroke (a) axially slidable with a cylinder-piston unit, for example a valve (18) cooperating, it is proposed that the cylinder-piston unit intermittently with pressure medium to act upon, causing the bit (24) is exposed to sudden forces during his intervention in the rock. In periods without pressurizing the cylinder-piston unit with pressurized fluid of the chisel (24) to be pushed into its initial position. The training can be hit with both hydraulic and pneumatic cylinder-piston units, which in the formation of a hydraulic cylinder-piston unit the configuration of this cylinder-piston unit as a valve (18) is preferably, soft at the same time a pressing of hydraulic fluid through a spray nozzle (32) allows to the working face.