3909557

Information

• Patent Grant
• 3909557

• References
• Source

• Patent Number

  3,909,557

• Date Filed

  Not available

• Date Issued

  Tuesday, September 30, 1975
  49 years ago

• CPC

  • H04R7/20 - Securing diaphragm or cone resiliently to support by flexible material, springs, cords, or strands
  • H04R9/042 - by pressurised air

• US Classifications

  • 381 - Electrical audio signal processing systems and devices