3320751

Information

• Patent Grant
• 3320751

• References
• Source

• Patent Number

  3,320,751

• Date Filed

  Not available

• Date Issued

  Tuesday, May 23, 1967
  57 years ago

• CPC

  • E21D23/06 - Special mine caps or special tops of pit-props for permitting step-by-step movement
  • E21D17/0206 - Hydraulically operated extension devices
  • E21D23/063 - Retractable cantilever extensions therefor

• US Classifications

  • 405 - Hydraulic and earth engineering
  • 248 - Supports