3840272

Information

• Patent Grant
• 3840272

• References
• Source

• Patent Number

  3,840,272

• Date Filed

  Not available

• Date Issued

  Tuesday, October 8, 1974
  50 years ago

• CPC

  • E21B7/208 - using down-hole drives
  • E21D3/00 - Raising shafts

• US Classifications

  • 299 - Mining or in situ disintegration of hard material
  • 173 - Tool driving or impacting
  • 175 - Boring or penetrating the earth
  • 405 - Hydraulic and earth engineering