Dentaphone (Theatre)
The larger Theatre Dentaphone was manufactured by the American Dentaphone Co. of
Cincinnati, Ohio, beginning in 1880. It consisted of a three-sectioned "fan"
made of hard rubber with a handle at the bottom end.
The larger Theatre Dentaphone measured 14" by 9⅜" overall. When
unfolded, the fan itself was 10½" x 9⅜". It was quite light at 2.8
oz.
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Rear view of the opened Theatre Dentaphone. The Dentaphone came in
two sizes—standard for normal use, and theatre size for use in larger
rooms such as theaters and auditoriums.
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The handle of the Dentaphone showing the nameplate immediately above it.
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The name plate on the Dentaphone reads "The American Dentaphone Co",
"Cincinnati, O." (for Ohio) and below that "Pat'd. Mar. 9th 1880".
Thomas W. Graydon received a US patent no.
2253655
for the
Dentaphone.
Click to read this patent.
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Since the Dentaphone uses bone conduction via the teeth, you held the
Dentaphone against your top teeth and flexed the hard rubber fan. The
sound waves vibrated the flexed fan. These vibrations were transmitted
to the inner ear via bone conduction from the teeth.
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Side view of the Dentaphone in use. By flexing the fan, the top of the
Dentaphone pressed against the upper teeth. Note: you didn't "bite"
the Dentaphone. It was only supposed to touch your top row of teeth.
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View of the post at the top of the handle on the back of the Dentaphone.
You pulled a rubber cord down and looped over the post. This kept the
fan from inadvertently folding while you were putting it up to your
mouth to use it.
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A rubber cord (not shown) was looped through the two holes—one on each
of the outside sections of the fan—then pulled down and looped over the
post. To fold it up again, you just unlooped the cord so the sides would
fold up.
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Front view of the Dentaphone in it's folded position. When folded is
was only 4¼" wide by 14" long.
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A close-up view of one of the six hinges—3 on each side to hold the
folding sections in place.
Note: There was at least one other "hearing aid" that was also called
a Dentaphone. However, this other one was totally different in size and shape.
It was about the size of a large pocket watch and had a wooden
mouthpiece connected to it by two wires. Just about every Internet
website that mentions Dentaphones shows the "Fan" Dentaphone but gives the
description of the "Watch
Dentaphone".
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