US5065660A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Piano tuning system
Assignee: Individual
•
Filing: 1990-05-29
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Granted: 1991-11-19
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Expires: 2010-05-29
Abstract
Abstract A system for tuning pianos and other string instruments utilizes a clamp-on probe with a feedback loop to induce a controlled vibration of the string and its natural frequency of vibration. This frequency is electronically compared to an accurate reference frequency. An associated electronic circuit controls an electric motor driven mechanism which adjusts the string tension until the correct frequency is achieved.
Inventors
- 👤 Eric de Buda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:04
CPC Classifications
G; G10; G10G; G10G7/00; G10G7/02; G10C; G10C9/00; Y; Y10; Y10S; Y10S84/00; Y10S84/18
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
146 words
A system for tuning piano strings, comprising: means for inducing a controlled vibration in the string at its natural frequency, comprising a sensor for sensing the string vibration, an actuator for transmitting controlled time-varying forces to the string, and a feedback loop comprising a signal processor modifying the phase of the signal from the sensor, feeding the actuator with processed signals from the sensor having the correct phase shift such that the string is caused to vibrate at its natural frequency; means for sensing the frequency of the vibration; means for comparing the vibration frequency against a reference frequency representing a desired frequency of vibration for the string; means for determining the frequency error of the vibration frequency relative to the reference frequency; control means for determining a motion required to reduce the frequency error; and means for adjusting string tension responsive to the control means.
Claim 2
Independent Claim
146 words
A system for tuning piano strings, comprising: means for inducing a controlled vibration in the string at its natural frequency, comprising a sensor for sensing the string vibration, an actuator for transmitting controlled time-varying forces to the string, and a feedback loop comprising a signal processor modifying the phase of the signal from the sensor, feeding the actuator with processed signals from the sensor having the correct phase shift such that the string is caused to vibrate at its natural frequency; means for sensing the frequency of the vibration; means for comparing the vibration frequency against a reference frequency representing a desired frequency of vibration for the string; means for determining the frequency error of the vibration frequency relative to the reference frequency; control means for determining a motion required to reduce the frequency error; and means for adjusting string tension responsive to the control means.
Claim 3
Independent Claim
82 words
A system for tuning piano strings, comprising: means for inducing a controlled vibration in the string at a chosen frequency close to its natural frequency; means for sensing the phase shift of the response of the string; means for determining the natural frequency error relative to a desired reference frequency, using information derived from the phase shift signal; control means for determining a motion required to reduce the natural frequency error; and means for adjusting string tension responsive to the control means.
Claim 4
Independent Claim
82 words
A system for tuning piano strings, comprising: means for inducing a controlled vibration in the string at a chosen frequency close to its natural frequency; means for sensing the phase shift of the response of the string; means for determining the natural frequency error relative to a desired reference frequency, using information derived from the phase shift signal; control means for determining a motion required to reduce the natural frequency error; and means for adjusting string tension responsive to the control means.
Claim 5
Dependent Claim
24 words
A system for tuning piano strings according to claim 2, wherein the signal processor compensates for signal delays in the sensor and the actuator.
Claim 6
Dependent Claim
43 words
A system for tuning piano strings according to claim 2 or 3, wherein means for inducing controlled vibration or means for sensing the controlled vibration is aligned with a string by a damper which is pivotally connected to a probe supporting said means.
Claim 7
Dependent Claim
46 words
A system for tuning piano strings according to claim 2, wherein the means for determining frequency error comprises a phase change detector measuring the phase between a reference frequency signal and a sensor signal for each cycle and comparing these measurements to measurements for previous cycles.
Claim 8
Dependent Claim
44 words
A system for tuning piano strings according to claim 2 or 3, wherein an indication or control signal is produced by a compensating circuit which causes the string to be tightened to a slightly higher frequency than the desired frequency to compensate for hysteresis.
Claim 9
Dependent Claim
73 words
A system for tuning piano strings according to claim 2 or 3, wherein the means for adjusting string tension comprises: a socket which mates with a tuning pin; a level arm which supplies torque to the socket; and anchoring means attached to an actuating device including a motor which provides force to the lever arm; whereby the anchoring means when affixed to the piano frame accommodates the reaction torque of a tuning motion.
Claim 10
Dependent Claim
62 words
A probe for inducing a controlled vibration in a string of a musical instrument comprising an actuator, a sensor, aligned with the actuator, for sensing the inherent frequency or phase of the vibration, a clamp for frictionally engaging a string in the vicinity of the string being actuated by the probe, wherein the sensor comprises a transmit coil and a receive coil.
Claim 11
Dependent Claim
62 words
A probe for inducing a controlled vibration in a string of a musical instrument comprising an actuator, a sensor, aligned with the actuator, for sensing the inherent frequency or phase of the vibration, a clamp for frictionally engaging a string in the vicinity of the string being actuated by the probe, wherein the sensor comprises a transmit coil and a receive coil.
Claim 12
Dependent Claim
22 words
A probe as defined in claim 8, wherein the transmit coil is mounted at substantially a right angle to the receive coil.
Claim 13
Dependent Claim
81 words
A probe for inducing a controlled vibration in a string of a musical instrument comprising an actuator, a sensor, aligned with the actuator, for sensing the inherent frequency or phase of the vibration, a clamp for frictionally engaging a string in the vicinity of the string being actuated by the probe, and a damper pivotally mounted in substantial alignment with the clamp to maintain the probe in proper alignment with the actuated string and damp out vibration in an adjacent string.
Claim 14
Dependent Claim
81 words
A probe for inducing a controlled vibration in a string of a musical instrument comprising an actuator, a sensor, aligned with the actuator, for sensing the inherent frequency or phase of the vibration, a clamp for frictionally engaging a string in the vicinity of the string being actuated by the probe, and a damper pivotally mounted in substantial alignment with the clamp to maintain the probe in proper alignment with the actuated string and damp out vibration in an adjacent string.
Claim 15
Dependent Claim
42 words
A system for tuning piano strings according to claim 3, wherein the means for inducing a controlled vibration comprises an actuator transmitting controlled time-varying forces to the string at a frequency within a range wherein the string will give a resonant response.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-11-18 | 1995-05-20 | 1995-11-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-11-18 | 1999-05-20 | 1999-11-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-11-18 | 2003-05-20 | 2003-11-19 | $7700.00 | Window Closed / Lapsed |