HOLE OPENER

摘要

The invention relates to drilling engineering, in particular to devices for enlarging the diameter of a hole within a specified range. The body of the inventive hole opener comprises radial orifices, a central through channel and a spring-loaded rod which is arranged in said channel and provided with orifices in the lower and top sections thereof. The top orifices are closed when the working members of the hole opener are in an operating position. Inclined slots are embodied on the external surface of the body and arms provided with pins are arranged therein. Said arms are arranged on supports with drilling cutters mounted thereon. Said supports are rigidly connected to cylindrical pistons which are arranged on the inclined borings of the body and whose cavities are connected to the central through channel thereof and tighten from environment. Said pistons are connected to the rod by means of sliders which are arranged in such a way that they are radially movable with respect to the rod and vertically movable along the slots of the body. Said invention increases the operating capacity and reliability of the opener.