# US 10,501,997 B2 · Drill bit with recessed cutting face > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,501,997 B2 - Document ID: US10501997B2 - Status: Granted - Kind: B2 - Application number: 15/505,995 - Filed: 2015-06-15 - Published: 2017-09-21 - Granted: 2019-12-10 - Earliest claimed: 2014-08-25 - Assignees: Sandvik Intellectual Property AB - Applicants: Sandvik Intellectual Property AB - Inventors: Andreas Rindeskar - Web page: https://patentgrep.com/patent/US10501997B2 ## CPC - E21B 10/38: characterised by conduits or nozzles for drilling fluids - E21B 10/36: Percussion drill bits ({with helical conveying portion E21B10/445;} characterised by wear resisting parts E21B10/46) - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS ## Abstract A percussive rock drill bit includes a head having an annular gauge collar and a central island. An annular cutting channel is defined between the collar and the island such that specifically positioned cutting buttons are effective to create an annular ridge in the cut rock face having a reduced rock breaking resistance. ## Claims ### Claim 1 A percussive rock drill bit head provided at one end of an elongate shank having an internal bore extending axially along a longitudinal axis from one end of the shank towards the head, the head comprising: an axially forward facing annular crushing face; a generally annular gauge collar projecting axially forward from the crushing face at a perimeter of the head and having a gauge face positioned axially forward of the crushing face; a central island being axially raised from the crushing face and having a front face positioned axially forward from the crushing face; a first and second generally annular shear face extending axially between the crushing face and the gauge face and the crushing face and the front face respectively, wherein the first and second shear faces are inclined at an angle to extend transverse to the longitudinal axis of the shank; at least one cutting button provided on each of the crushing, gauge, front and first and second shear faces; a plurality of curved flushing grooves in communication with the internal bore and extending radially outward from the island towards and through the gauge collar to separate the gauge collar into collar segments; and an annular channel being defined between the island and the gauge collar configured to create an annular ridge in the rock and accordingly reduce the rock breaking resistance. ### Claim 2 (depends on 1) The head as claimed in claim 1, wherein the crushing face is substantially planar or concave relative to a plane extending perpendicular to a longitudinal axis of the shank. ### Claim 3 (depends on 1) The head as claimed in claim 1, wherein the plurality of curved flushing grooves extend radially inward within regions of the island. ### Claim 4 (depends on 1) The head as claimed in claim 1, wherein the plurality of curved flushing grooves are recessed into the crushing face. ### Claim 5 (depends on 1) The head as claimed in claim 1, wherein the front face is positioned axially forward of the gauge face. ### Claim 6 (depends on 1) The head as claimed in claim 1, wherein the front face includes an axial depression to provide a fluid flow pathway between radially inner regions of the flushing grooves. ### Claim 7 (depends on 1) The head as claimed in claim 1, further comprising a plurality of flushing bores in communication with the internal bore and extending through the gauge collar to exit at the gauge face. ### Claim 8 (depends on 1) The head as claimed in claim 1, wherein the angle by which the first shear face is inclined relative to the longitudinal axis is in the range 1 to 20°. ### Claim 9 (depends on 1) The head as claimed in claim 1, wherein the angle by which the second shear face is inclined relative to the longitudinal axis is in the range 20 to 40°. ### Claim 10 (depends on 1) The head as claimed in claim 1, wherein along a radius extending from a centre of the head to a radially outermost perimeter, a separation distance between a radially innermost part of a cutting button on the first shear face and a radially outermost part of a closest cutting button on the second shear face is in the range 10 to 30% of the radius. ### Claim 11 (depends on 10) The head as claimed in claim 10, wherein said range is 15 to 25%. ### Claim 12 (depends on 1) The head as claimed in claim 1, wherein a radial distance of the crushing face defined between the first and second shear faces is 5 to 20% of a radius of the head defined between a centre of the head and a radially outermost perimeter part of the cutting buttons at the gauge collar. ### Claim 13 (depends on 1) The head as claimed in claim 1, wherein an axial separation distance between the front face and the crushing face is in the range 25 to 45% of an axial length of the head defined between an axially forwardmost part of the cutting button at the front face and an axially rearwardmost part of a skirt that represents an axially rearwardmost part of the gauge collar extending directly from the shank. ### Claim 14 (depends on 13) The head as claimed in claim 13, wherein said range is 30 to 40%.