| 摘要 |
FIELD: mining industry. ^ SUBSTANCE: device has body with axial channel and apertures, sub onto drilling column, pilot chisel, expander chisels, paws of which have threaded tail pieces, and placed in apertures of body, holders of expander chisels. Holders are made in form of closed threaded bushings with teeth in upper part, and sub on drilling column is made flanged with teeth in lower part, mounted with possible interaction with teeth of holders bushings. In body and holders radial channels are made, connecting hollows of axial channel of body and axial channels of expander chisels. ^ EFFECT: higher speed of operation. ^ 1 dwg |
