1721023

Information

• Patent Grant
• 1721023

• References
• Source

• Patent Number

  1,721,023

• Date Filed

  Not available

• Date Issued

  Tuesday, July 16, 1929
  95 years ago

• CPC

  • H04R9/042 - by pressurised air

• US Classifications

  • 335 - Electricity: magnetically operated switches, magnets, and electromagnets