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US 4,380,689 AGranted
Electroacoustic transducer for hearing aids
OwnerVittorio Giannettiinventor
Life of this patent
Estimating the term…
Abstract
An electroacoustic transducer is disclosed which is small in size so as to allow its use in hearing aids or like structure, but which maintains the performance characteristics of larger transducers. The transducer minimizes its cross-sectional dimensions by aligning the permanent magnet with the soft iron core instead of placing it outside the core. Adjustment of the magnetic flux is provided by a screw trimmer adjustable from the exterior of the transducer.
Claims12
An electroacoustic transducer comprising:
- (a) a main support having a hollow cylindrical body defining a bore, and a central opening communicating with said bore;
- (b) a body defining a central bore and attached to said main support such that said central bore is disposed about said cylindrical body;
- (c) a closure disc attached to said cylindrical body across said bore;
- (d) an annular, flat permanent magnet located on said closure disc within said bore;
- (e) a magnetizable core attached to, and aligned with said permanent magnet;
- (f) an electrical winding or coil disposed around said magnetizable core and located between said core and said cylindrical body, said winding or coil being electrically connected to an electroacoustic amplifying circuit;
- (g) a vibrating disc;
- (h) means attaching said vibrating disc across said central opening in the main support such that it is in close proximity to an end of said magnetizable core;
- and
- (i) means to adjustably modify the magnetic flux of said annular, flat permanent magnet.
7 more elements
Dependencies are inferred from the claim text.