1331728

Information

• Patent Grant
• 1331728

• References
• Source

• Patent Number

  1,331,728

• Date Filed

  Not available

• Date Issued

  Tuesday, February 24, 1920
  104 years ago

• CPC

  • G09B13/02 - Dummy practice keyboard apparatus

• US Classifications

  • 434 - Education and demonstration
  • 400 - Typewriting machines