3378305

Information

• Patent Grant
• 3378305

• References
• Source

• Patent Number

  3,378,305

• Date Filed

  Not available

• Date Issued

  Tuesday, April 16, 1968
  56 years ago

• CPC

  • E21D9/0873 - the shield being provided with devices for lining the tunnel
  • E21D9/065 - with devices for provisionally supporting the front face
  • E21D9/087 - with a rotary drilling-head cutting simultaneously the whole cross-section

• US Classifications

  • 299 - Mining or in situ disintegration of hard material
  • 405 - Hydraulic and earth engineering