1642885

Information

• Patent Grant
• 1642885

• References
• Source

• Patent Number

  1,642,885

• Date Filed

  Not available

• Date Issued

  Tuesday, September 20, 1927
  97 years ago

• CPC

  • E21F1/006 - Ventilation at the working face of galleries or tunnels
  • E21C27/06 - with a slewing frame

• US Classifications

  • 299 - Mining or in situ disintegration of hard material