Device for intermittently subjecting axially shiftable bits of a cutting

Abstract

The device for intermittently subjecting axially shiftable bits of a cutting head to the action of pressurized fluids comprises bit holders in which the bits are supported for a limited movement in axial direction. The bits are subjected to the action of a percussion piston which is intermittently supplied with pressurized fluid. A distributor 6 is provided for intermittently supplying pressure and includes a bushing-shaped distributing slide valve 18. The distributing slide valve 18 is provided in its mantle surface with radial perforations 22 which can be brought in alignment with passages 7 of a cutting head 3. There is provided an interpositioned gearing comprising a sun wheel 13, intermediate gear wheels 11 bearingly supported on a carrier 10 fixed for not being rotatable and a hollow gear wheel 15 non-rotatably connected with the cutting head 3. The bushing-shaped distributing slide valve 18 is non-rotatably connected with the sun wheel 13 being rotated in this manner by the cutting head 3, noting that the distributing slide valve 18 is rotated in a sense opposite to the sense of rotation of the cutting head 3. Supply of water is effected via an intermediate piece 20 into an axial water supply bolt 9 from which the water is intermittently supplied to the percussion pistons within the bit holders via the perforations 22 of the distributing slide valve 18.