3818616

Information

• Patent Grant
• 3818616

• References
• Source

• Patent Number

  3,818,616

• Date Filed

  Not available

• Date Issued

  Tuesday, June 25, 1974
  50 years ago

• CPC

  • G09B1/22 - and bearing the symbols on a surface perpendicular to the axis of rotation

• US Classifications

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