DEVICE FOR COOLING THE BITS OF A CUTTING MACHINE

摘要

The bits (1) of a cutting machine are subjected with water under pressure by means of nozzles (22), water supply to the nozzles (22) being given free by a valve cone (6) as soon as the bit (1) within the bit holder (2) is shifted in axial direction against the force of a spring. Axial movement of the bit (1) is effected by the cutting pressure and the shifting path of the bit (1) is transmitted to the valve cone (6) via a coupling member (9). The force of the spring (5) is rated such that the spring presses the bit (1) against its own weight and against the internal frictional resistances into its starting position in non-loaded condition with simultaneous closing of the valve cone (6). The restoring forces are, with connected conduits for pressurized water, substantially greater than the spring force, the active surface of the valve cone (6) acted upon by the water pressure in closing sense determining the force above which opening of the valve becomes possible. The valve is only opened above a minimum hardness of the rock and thus above a predetermined lower limit for the cutting pressure (FIG. 1).