2218491

Information

• Patent Grant
• 2218491

• References
• Source

• Patent Number

  2,218,491

• Date Filed

  Not available

• Date Issued

  Tuesday, October 15, 1940
  84 years ago

• CPC

  • E21C25/66 - Machines for making slits with additional arrangements for drilling

• US Classifications

  • 173 - Tool driving or impacting
  • 299 - Mining or in situ disintegration of hard material