3387892

Information

• Patent Grant
• 3387892

• References
• Source

• Patent Number

  3,387,892

• Date Filed

  Not available

• Date Issued

  Tuesday, June 11, 1968
  56 years ago

• CPC

  • E21D9/118 - with independently driven central head
  • E21D9/113 - having a central part for making a pilot tunnel and a follow-up part for enlarging the pilot tunnel

• US Classifications

  • 299 - Mining or in situ disintegration of hard material
  • 175 - Boring or penetrating the earth