UNDERWATER EARPHONE

• US 3,764,966 A
• Filed: 03/08/1972
• Issued: 10/09/1973
• Est. Priority Date: 03/08/1972
• Status: Expired due to Term

• Current Assignee: Louis A. Abbagnaro
• Original Assignee: Louis A. Abbagnaro
• Inventors: Abbagnaro, Louis A.
• Primary Examiner(s): Farley, Richard A.
• Application Number:
  US05/232,800
• Time in Patent Office: 580 Days
• Field of Search: 340/5R,5T,8PC,8LF,14
• US Class Current: 367/171
• CPC Class Codes: G01S 1/72 using ultrasonic, sonic or infrasonic waves
• CPC Class Codes: H04R 13/00 Transducers having an acoustic diaphragm of magnetisable material directly co-acting with electromagnet

Abstract

An underwater earphone having a cylindrical casing sealed at one end by the vibratable diaphragm and at the other end by a flexible rubber diaphragm. The casing, including pole pieces and energizing coils is filled with silicone oil providing damping. This construction equalizes the pressure on either side of the vibratable diaphragm and prevents the ingress of water.

Claims

1. An earphone for use in an underwater environment comprising:

a cylindrical casing;

an electromagnetic circuit contained in said casing including;

a pair of soft iron pole pieces, a permanent magnet affixed between the ends of said pole pieces, and a pair of series-connected coils, each of which surrounds one of said pair of pole pieces;

a vibratable diaphragm completing said circuit thru an air gap and sealingly secured at its periphery to the front end of said casing;

a flexible diaphragm sealedly secured at its periphery to the rear end of said casing; and

an incompressible fluid completely filling said casing, whereby an ambient pressure on the face of said vibratable diaphragm is counteracted by an equal and opposite pressure from the inside of said casing transmitted through said fluid and by said flexible diaphragm in contact with the environment.

2. The earphone of claim 1 wherein said vibratable diaphragm is composed of Vanadium Permandue.

3. The earphone of claim 2 wherein said flexible diaphragm is composed of rubber.

4. The earphone of claim 3 wherein said imcompressible fluid comprises silicone oil.

5. The earphone of claim 4 wherein said electromagnetic circuit is secured to said casing by an apertured disc whereby flow of said silicone oil is permitted from the front to the rear of said casing.