3383868

Information

• Patent Grant
• 3383868

• References
• Source

• Patent Number

  3,383,868

• Date Filed

  Not available

• Date Issued

  Tuesday, May 21, 1968
  56 years ago

• CPC

  • E21D23/066 - Pivoted cantilever extensions therefor
  • E21D17/0206 - Hydraulically operated extension devices
  • E21D23/0052 - with advancing shifting devices connected therewith
  • E21D23/06 - Special mine caps or special tops of pit-props for permitting step-by-step movement
  • E21D23/081 - forming parts of the roof supports

• US Classifications

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