3640574

Information

• Patent Grant
• 3640574

• References
• Source

• Patent Number

  3,640,574

• Date Filed

  Not available

• Date Issued

  Tuesday, February 8, 1972
  52 years ago

• CPC

  • E21D17/0206 - Hydraulically operated extension devices

• US Classifications

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