HOLE OPENER

The invention relates to drilling technique, in particular, to devices for borehole reaming within a specified interval. The housing has radial holes and a central straight-through channel, in which a spring-loaded rod with holes in the upper and lower parts is located, where the upper holes are covered in extension of the operating elements into working position. On the outer surface of the housing the inclined slots are made, in which legs are fastened with journals, fastened in supports, and on which journals rolling cutters are fixed. The supports are rigidly connected with cylindrical pistons, arranged in inclined bores of the housing, which chambers communicate with its central straight-through channel and are isolated from the annulus. Pistons are connected with the rod by sliders. And the sliders have a possibility of radial movements with respect to the rod and vertical movements in slots of the housing. The invention increases serviceability and reliability of the reamer.