3240021

Information

• Patent Grant
• 3240021

• References
• Source

• Patent Number

  3,240,021

• Date Filed

  Not available

• Date Issued

  Tuesday, March 15, 1966
  58 years ago

• CPC

  • E21D17/082 - of sliding type
  • E21D17/0206 - Hydraulically operated extension devices
  • E21D17/08 - Cap joints for obtaining a coal-face free of pit-props
  • E21D23/063 - Retractable cantilever extensions therefor

• US Classifications

  • 405 - Hydraulic and earth engineering
  • 052 - Static structures
  • 248 - Supports