|7296641||Rock drill bit having outer and inner rock-crushing buttons|
A rock drill bit for percussive drilling includes a front face which has radially outer and inner portions. Fluid channels are disposed in the head portion in communication with the inner portion of the front face. The inner portion of the front face carries a plura...
|6845827||Rock drill head|
A drill head for rock drilling comprising cutting edges (1) made of hard material, which is detachably connected axially, over a bearing surface (3), with a drilling shaft (4) with at least one radially projecting driver blade (5a
|5836408||Rotary percussion blow assisted drill|
A rotary percussion blow assisted drill has an axially extending shank (1) with at least one main helically extending groove (4) in its axially extending outside surface (2) for conveying drilled material along the shank. A cutting plate (6) with hard met...
|4722402||Electromagnetic drilling apparatus and method|
Oil well drilling apparatus for drilling deep boreholes. The apparatus includes a high frequency, high voltage, AC generator at the surface of the ground which is connected to an electromagnetic hammer drill bit located at the bottom of the borehole. Elec...
|4716976||Rotary percussion drill bit|
A rotary percussion rock drill bit has a body and a symmetrical cross-like arrangement of crushing and cutting inserts secured on the body. The bit body has a rearward shank portion and a forward boring head portion with a front face. The cylindrical crus...
|4265325||Percussion rock bit|
In a percussive rock bit or similar tool wherein cemented carbide cutting inserts are retained in open radial slots in the head of the tool, an improved method of mechanically retaining the inserts. The inserts are provided with a plurality of elongated r...
|4185708||Bit for drilling holes in rocks|
A bit for drilling holes in rocks comprising inserts of sintered carbide, the base of which in a plane perpendicular to the edge of its drill point follows a downward convex curve along the symmetry axis of the cross-section of the insert. The insert has ...
Rotary percussive drill bits comprising a body having a longitudinal axis, side face, end face, and cutting inserts, arranged such that during rotary percussive drilling wear tends to take place over a clearance face of the insert thus preserving the lead...