Resources Contact Us Home
Browse by Category: Main > Communications
Class Information
Number: 181/138
Name: Acoustics > Mechanical telephone
Description: Subject matter wherein sound is transmitted by the vibrations of molecules set up by mechanical means in a wire, string or flexible member strung taut.

Patents under this class:

Patent Number Title Of Patent Date Issued
5579398 Electro-acoustic transducer Nov. 26, 1996
5127870 Echo-type toy megaphone Jul. 7, 1992
4195707 Communicating device Apr. 1, 1980
4194095 Fluid flow control speaker system Mar. 18, 1980
4187635 Method and apparatus for sound production Feb. 12, 1980
4002897 Opto-acoustic telephone receiver Jan. 11, 1977

  Recently Added Patents
Chair structure
Magnetic circuit and speaker using same
Contact sensor, driver device, and care bed
Communications in an asynchronous cellular wireless network
Smooth silicon-containing films
Reducing voltage stress in a flyback converter design
  Randomly Featured Patents
Medical examining lamp
Method and device for a data processing and communication system comprising such device
Self-timed differential comparator
Size independent modular web processing line and modules
Objective lens drive device with tracking error correction with flux of opposite direction
Method for making a high-temperature superconducting field-effect transistor with thick superconducting channel layer
Smetic liquid crystal compound
Supercritical fluid fractionation process for phytosterol ester enrichment vegetable oils
Combustion gas powered tool
Catalyst based on an organic-inorganic hybrid support and its use in hydrorefining and hydroconversion