3902325

Information

• Patent Grant
• 3902325

• References
• Source

• Patent Number

  3,902,325

• Date Filed

  Not available

• Date Issued

  Tuesday, September 2, 1975
  49 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
  • E21D23/0039 - and supported by a strut or by a row of struts parallel to the working face

• US Classifications

  • 405 - Hydraulic and earth engineering