# US 2016/0258221 A1 · Expandable Diameter Drill Bit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2016/0258221 A1 - Document ID: US20160258221A1 - Status: Published application - Kind: A1 - Application number: 14/636,907 - Filed: 2015-03-03 - Published: 2016-09-08 - Earliest claimed: 2015-03-03 - Inventors: Lawrence L. Macha - Web page: https://patentgrep.com/patent/US20160258221A1 ## CPC - E21B 10/325: {the cutter being shifted by a spring mechanism} - E21B 10/54: the bit being of the rotary drag type, e.g. fork-type bits - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS ## Abstract An expandable diameter drill bit includes a cutting blade having receiving and contacting ends, the receiving end having a pivot shaft and the contacting end having a tip. A drill bit includes a drill head body having an upper attachment portion and a lower body portion, the lower body portion defining a blade opening for receiving the receiving end of the cutting blade and a bolt receiving hole on opposing sides transverse the blade opening. The drill bit includes a torsion spring, a first blade leg, and a second body leg. The blade bolt passes through the bolt receiving holes and the pivot shaft and secured with a set screw. The first blade leg is coupled to the cutting blade with a spring retainer bolt, the second body leg is coupled to the drill head body, and the torsion spring biases the blade outwardly from the drill head body. ## Claims ### Claim 1 An expandable diameter drill bit, comprising: a cutting blade having a receiving end and a contacting end, the receiving end having a pivot shaft and the contacting end having a tip; a drill head body having an upper attachment portion and a lower body portion, the lower body portion defining: a blade opening configured to receive the receiving end of the cutting blade; and a bolt receiving hole on each of two opposing sides transverse the blade opening; and a torsion spring having a helical coil, a first blade leg, and a second body leg; wherein: the blade is received in the blade opening such that the pivot shaft corresponds to the bolt receiving holes; a blade bolt passes through the bolt receiving holes and the pivot shaft and is secured into position with a blade bolt set screw; the first blade leg is secured to the cutting blade with a spring retainer bolt; the second body leg is secured into the drill head body; and the torsion spring biases the blade outwardly from the drill head body. ### Claim 2 (depends on 1) The drill bit of claim 1, wherein an outer edge of the contacting end of the cutting blade includes a serrated configuration. ### Claim 3 (depends on 1) The drill bit of claim 1, wherein an outer edge of the cutting blade is coated with a hardened material selected from the group consisting of tungsten carbide, cubic boron nitride, and diamond. ### Claim 4 (depends on 1) The drill bit of claim 1, wherein the first blade leg is configured to receive an insert, and wherein the insert is coated with a material selected from the group consisting of tungsten carbide, cubic boron nitride, and diamond. ### Claim 5 (depends on 3) The drill bit of claim 3, wherein the lower body portion further includes a fluid discharge hole for discharging fluid away from the drill bit. ### Claim 6 (depends on 1) The drill bit of claim 1, wherein said lower body portion has at least two blade receiving areas, each blade receiving area being configured to receive a separate blade. ### Claim 7 (depends on 6) The drill bit of claim 6, wherein the blades are oppositely biased. ### Claim 8 (depends on 1) The drill bit of claim 1, wherein the upper attachment portion has a generally conically shaped configuration and includes threads. ### Claim 9 An expandable diameter drill bit, comprising: a first cutting blade and a second cutting blade, each cutting blade having a receiving end and a contacting end; a drill head body having an upper attachment portion and a lower body portion, the lower body portion defining a first blade opening and a second blade opening configured to receive respective receiving ends of respective cutting blades, the first blade opening and the second blade opening being separated by a divider; a first torsion spring coupled to the first cutting blade and to the drill head body; a second torsion spring coupled to the second cutting blade and to the drill head body; a blade bolt inserted transversely through the lower body portion and the first and second cutting blades, the first cutting blade and the second cutting blade being configured to pivot about the blade bolt; wherein the first and second torsion springs bias the blades outwardly from the drill head body in opposing directions respectively. ### Claim 10 (depends on 9) The drill bit of claim 9, wherein the cutting blades have serrated edges. ### Claim 11 (depends on 10) The drill bit of claim 10, wherein the serrated edges are coated with a material selected from the group consisting of tungsten carbide, cubic boron nitride, and diamond. ### Claim 12 (depends on 9) The drill bit of claim 9, wherein the first and second cutting blades are coated with a material selected from the group consisting of tungsten carbide, cubic boron nitride, and diamond. ### Claim 13 (depends on 9) The drill bit of claim 9, wherein: the first and second torsion springs each have a central coil, a first leg, and a second leg; a respective first leg is attached to a respective cutting blade and a respective second leg is inserted into a designated cavity in the lower body portion. ### Claim 14 (depends on 13) The drill bit of claim 13, wherein the first and second cutting blades are configured to receive an insert; and the insert is coated with a material selected from the group consisting of tungsten carbide, cubic boron nitride, and diamond. ### Claim 15 (depends on 13) The drill bit of claim 13, wherein: the first blade leg of the first torsion spring is secured in a channel in the first cutting blade with a spring retainer bolt; the second body leg of the first torsion spring is inserted into the drill head body; the first blade leg of the second torsion spring is secured in a channel in the second cutting blade with a spring retainer bolt; and the second body leg of the second torsion spring is inserted into the drill head body. ### Claim 16 (depends on 9) The drill bit of claim 9, wherein the lower body portion defines a fluid discharge hole for discharging fluid away from the drill bit. ### Claim 17 An expandable diameter drill bit, comprising: a first cutting blade and a second cutting blade, each cutting blade having a receiving end and a contacting end; each receiving end having a pivot shaft; a drill head body having an upper threaded portion and a lower body portion, the lower body portion defining: a first blade opening for receiving the receiving end of the first cutting blade; a second blade opening for receiving the receiving end of the second cutting blade; a bolt receiving hole on each of two opposing sides transverse the blade openings, respectively; and a first torsion spring and a second torsion spring, each spring having a helical coil, a first blade leg, and a second body leg; wherein: the first and second blades are received in respective blade openings such that respective pivot shafts correspond to respective bolt receiving holes; a blade bolt is inserted through respective bolt receiving holes and the pivot shafts are secured into position with a blade bolt set screw; the first blade leg of the first torsion spring is secured in a channel in the first cutting blade with a spring retainer bolt; the second body leg of the first torsion spring is inserted into the drill head body; the first blade leg of the second torsion spring is secured in a channel in the second cutting blade with a spring retainer bolt; the second body leg of the second torsion spring is inserted into the drill head body; the torsion springs bias the first and second blades outwardly from the drill head body; and the surface contact ends of the first and second cutting blades are coated in tungsten carbide forming a scalloped surface. ### Claim 18 (depends on 17) The drill bit of claim 17, wherein the blade bolt is secured in place with a blade bolt set screw. ### Claim 19 (depends on 18) The drill bit of claim 18, wherein the first and second blades are oppositely biased. ### Claim 20 (depends on 19) The drill bit of claim 19, wherein the first and second cutting blades have serrated edges.