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US 4,088,052 AGranted
String instrument tuning apparatus
OwnerW. David Hedrickinventor
Life of this patent
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OwnerW. David Hedrickinventor
Estimating the term…
This disclosure pertains to an apparatus utilized to detect the pitch in a string instrument, comparing it with a known standard, and providing an output error signal to an audio amplifier which drives a motor and gear train. The output shaft of the gear train is removably attached to the string tensioning pin. A timer activates the correcting motor in short bursts facilitating the manual striking of the string so as to produce a tone that may be measured. When the motor successfully adjusts the pitch produced by the string, the error signal is reduced sufficiently to prevent further motorized adjustments of the string tension. A meter is provided to indicate the relative pitch produced by the string by displaying the amplitude of the error signal. Locking means prevents the output shaft from being rotated by the motor, thereby enabling the user to manually adjust the pin when desired.
A string instrument tuning apparatus comprising a handheld tuning apparatus, a musical string instrument, string tensioning pin receiving receptacle, said pin receiving receptacle rotatably journalled to said tuning apparatus, a motor, said motor for rotating said pin receiving receptacle, audible detection means for receiving tones produced by said musical string instrument, voltage generating means for selectively producing one of a plurality of standard frequency voltages, selector switch means for separately electrically selecting said one of said plurality of standard frequency voltages, comparator means for providing an error signal voltage whose amplitude is proportioned to the difference in frequency of said tones and said one of said plurality of standard frequency voltages, motor energizing means for energizing said motor from said error signal voltage, timing means for intermittently controlling the timed duration of energization of said motor.
Dependencies are inferred from the claim text.