2840179

Information

• Patent Grant
• 2840179

• References
• Source

• Patent Number

  2,840,179

• Date Filed

  Not available

• Date Issued

  Tuesday, June 24, 1958
  66 years ago

• CPC

  • E04B1/8409 - sheet-shaped
  • G10K11/172 - using resonance effects
  • E04B2001/8414 - with non-planar face
  • E04B2001/8433 - with holes in their face
  • E04B2001/8447 - with two faacing trays
  • E04B2001/8461 - layered
  • E04B2001/8485 - the opening being restricted

• US Classifications

  • 181 - Acoustics