2804754

Information

• Patent Grant
• 2804754

• References
• Source

• Patent Number

  2,804,754

• Date Filed

  Not available

• Date Issued

  Tuesday, September 3, 1957
  67 years ago

• CPC

  • E21D9/0873 - the shield being provided with devices for lining the tunnel

• US Classifications

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