3325217

Information

• Patent Grant
• 3325217

• References
• Source

• Patent Number

  3,325,217

• Date Filed

  Not available

• Date Issued

  Tuesday, June 13, 1967
  57 years ago

• CPC

  • E21D9/1053 - for making a slit along the perimeter of the tunnel profile, the remaining core being removed subsequently

• US Classifications

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