DEVICE FOR MAKING HOLES IN GROUND Russian patent published in 1994 - IPC

FIELD: hole making equipment. SUBSTANCE: device has drive shaft, eccentric bushings and rollers. Bushings are successively arranged on drive shaft. Each roller is installed on respective bushing for rotation. Outer diameter of rollers successively increases from main roller. Roller symmetry longitudinal axes are successively turned round longitudinal symmetry axis of drive shaft and displaced relative to it. Roller symmetry longitudinal axes are positioned at an angle to shaft longitudinal axis. Drive shaft has projections. Each bushing, except for the main one, has recess on its inner surface to receive corresponding projection of drive shaft. Bushings are installed for limited turning round longitudinal symmetry axis of drive shaft during shaft reverse. Recess length on respective bushings is determined by design formula. EFFECT: higher efficiency. 4 dwg