2221392

Information

• Patent Grant
• 2221392

• References
• Source

• Patent Number

  2,221,392

• Date Filed

  Not available

• Date Issued

  Tuesday, November 12, 1940
  84 years ago

• CPC

  • E21B25/14 - mounted on pivot transverse to core axis

• US Classifications

  • 175 - Boring or penetrating the earth