electromagnetic tuning fork
Date1910-1915
Inventory Number2005-1-0020
ClassificationTuning Fork
Subject
Maker
Western Electric Company
1869 - 1995
Cultural Region
Place of Origin
Dimensions15.2 x 20 x 54.6 cm (6 x 7 7/8 x 21 1/2 in.)
Material
DescriptionA steel tuning fork is fixed at one end of a rectangular base. On the base, four connectors are added to power the apparatus in electricity. Two other connectors are supported by a steel bridge in the middle of the apparatus. When the electromagnetic coil is powered, it forces the tuning fork to vibrate (the frequency of the vibration is fine-tuned by the big knob at the front, which to do so moves an adjustment slider in between the forks). A fine metallic strip is added to each fork, and when the latter vibrates the strips come on and off contact with the elevated connectors supported by that bridge. It is what produces or regulates the transmission of a multiplicity of sound signals. A switch turns the whole apparatus on and off.
Signedon front: Western Electric / COMPANY
Inscribedon tag: From / American Telephone and Telegraph Co. / 195 Broadway, New York, N. Y. / Electro-magnetically driven / tuning fork for operating / Phonic-wheel motor
on top of base: MULTIPLEX / DRIVING FORK I-A
on right side: PATENTED IN U.S.A. / DECEMBER 13, 1904 / PATENT APPLIED FOR
on right side: 194
beneath base, under switch: H & H / PAT. NOV. 30-97 / OCT. 11-10 / 2082
FunctionThis device was used in operating a phonic-wheel motor, which was itself used in the transmission of electrical signal carrying the voice in early telephony. This being a multiplex tuning fork, it could dispatch several different signals at the same time.
Louis Jules Duboscq
Date: circa 1870
Object number: 1997-1-0929
Louis Jules Duboscq
Date: circa 1870
Object number: 1997-1-0930
Rudolph Koenig
Date: circa 1865
Object number: 1996-1-0421
Rudolph Koenig
Date: circa 1889
Object number: 1997-1-0884
Rudolph Koenig
Date: circa 1890
Object number: WJ0042
Rudolph Koenig
Date: circa 1865
Object number: 1997-1-0892f