3673712

Information

• Patent Grant
• 3673712

• References
• Source

• Patent Number

  3,673,712

• Date Filed

  Not available

• Date Issued

  Tuesday, July 4, 1972
  52 years ago

• CPC

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

• US Classifications

  • 434 - Education and demonstration