Drill bits

EFIXED CONSTRUCTIONS E21Mining E21BEARTH DRILLING

E21B10/00Drill bits

E21B10/003with cutting edges facing in opposite axial directions E21B10/006providing a cutting edge which is self-renewable during drilling E21B10/02Core bits E21B10/04with core destroying means E21B10/06Roller core bits E21B10/08Roller bits E21B10/083with longitudinal axis E21B10/086with excentric movement E21B10/10with roller axle supported at both ends E21B10/12with discs cutters E21B10/14combined with non-rolling cutters other than of leading-portion type E21B10/16characterised by tooth form or arrangement E21B10/18characterised by conduits or nozzles for drilling fluids E21B10/20characterised by detachable or adjustable parts E21B10/22characterised by bearing, lubrication or sealing details E21B10/23with drilling fluid supply to the bearings E21B10/24characterised by lubricating details E21B10/246with pumping means for feeding lubricant E21B10/25characterised by sealing details E21B10/26Drill bits with leading portion, i.e. drill bits with a pilot cutter Drill bits for enlarging the borehole E21B10/28with non-expansible roller cutters E21B10/30Longitudinal axis roller reamers E21B10/32with expansible cutting tools E21B10/322cutter shifted by fluid pressure E21B10/325the cutter being shifted by a spring mechanism E21B10/327the cutter being pivoted about a longitudinal axis E21B10/34of roller-cutter type E21B10/345cutter shifted by fluid pressure E21B10/36Percussion drill bits E21B10/38characterised by conduits or nozzles for drilling fluids E21B10/40with leading portion E21B10/42Rotary drag type drill bits with teeth, blades or like cutting elements E21B10/43characterised by the arrangement of teeth or other cutting elements E21B10/44Bits with helical conveying portion E21B10/445percussion type E21B10/46characterised by wear resisting parts E21B10/48the bit being of core type E21B10/485with inserts in form of chisels, blades or the like E21B10/50the bit being of roller type E21B10/52with chisel or button type inserts E21B10/54the bit being of the rotary drag type E21B10/55with preformed cutting elements with blades having preformed cutting elements mounted on a distinct support E21B10/56Button type inserts E21B10/567with preformed cutting elements mounted on a distinct support E21B10/5673having a non planar or non circular cutting face E21B10/5676having a cutting face with different segments E21B10/573characterised by support details E21B10/5735Interface between the substrate and the cutting element E21B10/58Chisel type inserts E21B10/60characterised by conduits or nozzles for drilling fluids E21B10/602the bit being a rotary drag type bit with blades E21B10/605the bit being a core-bit E21B10/61characterised by the nozzle structure E21B10/62characterised by parts E21B10/627with plural detachable cutting elements E21B10/633independently detachable E21B10/64characterised by the whole or part thereof being insertable into or removable from the borehole without withdrawing the drilling pipe E21B10/66the cutting element movable through the drilling pipe and laterally shiftable