DEVICE FOR WIDENING BORE-HOLES IN GROUND Russian patent published in 1998 - IPC

FIELD: construction engineering. SUBSTANCE: increased drilling speed and simplified mounting and operation are achieved due to making shoulder movable in axial direction relative to body of pneumatic puncher and possibility of its fixing in any required position. Shoulder is provided with surface which embraces smaller stage of longitudinal sections of widener. Aforesaid surface can be made cylindrical or tapered. This embodiment of device simultaneously ensures optimization of bore-hole driving speed depending on density of ground, prevents radial or axial displacement of widener relative to body of pneumatic puncher, simplifies erection of widener on pneumatic puncher and removal of device from bore-hole. EFFECT: higher efficiency. 4 cl, 5 dwg