1678621

Information

• Patent Grant
• 1678621

• References
• Source

• Patent Number

  1,678,621

• Date Filed

  Not available

• Date Issued

  Tuesday, July 24, 1928
  97 years ago

• CPC

  • G09B1/28 - the elements being slidable

• US Classifications

  • 434 - Education and demonstration
  • 040 - Card, picture, or sign exhibiting