3712071

Information

• Patent Grant
• 3712071

• References
• Source

• Patent Number

  3,712,071

• Date Filed

  Not available

• Date Issued

  Tuesday, January 23, 1973
  51 years ago

• CPC

  • E21D19/04 - for use in drifting galleries
  • E21D9/0879 - the shield being provided with devices for lining the tunnel
  • E21D11/03 - using timber- setting machines

• US Classifications

  • 405 - Hydraulic and earth engineering