Acoustic coupler for earphones
United States Patent 2584402
US Patent References:
Telephone receiver
- - 1642776
Audiphone
- - 1753817
Electrically and acoustically excited hearing aid
- - 2363175
Hearing aid earpiece
- - 2430229
Telephone receiver
- - 1642776
Audiphone
- - 1753817
Electrically and acoustically excited hearing aid
- - 2363175
Hearing aid earpiece
- - 2430229
Inventors:
John, Volkmann
Publication Date:
02/05/1952
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Export Citation:
Assignee:
John, Volkmann
Primary Class:
Other Classes:
381/382, D14/242, D24/174
International Classes:
H04R25/02