3881775

Information

• Patent Grant
• 3881775

• References
• Source

• Patent Number

  3,881,775

• Date Filed

  Not available

• Date Issued

  Tuesday, May 6, 1975
  50 years ago

• CPC

  • E21B7/28 - Enlarging drilled holes
  • E21B11/06 - with driven cutting chains or similarly driven tools
  • E21B43/29 - Obtaining a slurry of minerals

• US Classifications

  • 299 - Mining or in situ disintegration of hard material
  • 175 - Boring or penetrating the earth
  • 406 - Conveyors: fluid current