DRAG DRILL BIT Russian patent published in 2002 - IPC

FIELD: rock-breaking tools. SUBSTANCE: drag drill bit has body with central hole, blades with plug-in cutting picks, flexible branch pipe attached with upper end to body. Lower end of flexible branch pipe is fitted with extension piece and weight coming in the form of bushing. Upper part of one of blades in space of central hole has either geometrical form or geometrical dimensions different from other blades. Operation of one of blades differing from other blades leads to formation of force by flow of flushing fluid that deflects flexible branch pipe. Coriolis and centrifugal forces will act on branch pipe in process of rotation of drill bit. As result of action of these forces lower end of branch pipe will run on surface of one of blades. Under action of flows repelled from surface of blade flexible branch pipe will deviate from surface of blade and so on. Lower end of branch pipe will make complicated motion relative to drill bit. Due to this motion of lower end of flexible branch pipe flow of flushing fluid will be directed in sequence to one or another sector and so forth. As result sliming of interpick spaces is prevented which increases efficiency and reliability of operation of drag drill bit. EFFECT: increased efficiency and reliability of operation of drag drill bit. 4 dwg