3643421

Information

• Patent Grant
• 3643421

• References
• Source

• Patent Number

  3,643,421

• Date Filed

  Not available

• Date Issued

  Tuesday, February 22, 1972
  52 years ago

• CPC

  • G04C21/20 - by closing a contact to ring an electro-mechanical alarm
  • G04C21/36 - Signal repeating devices

• US Classifications

  • 368 - Horology: time measuring systems or devices
  • 968 - Horology