Patent Application
20100089219
Many stringed instruments, and guitars in particular, require periodic tuning to remain playable. Due to the stresses on the strings and the tuning mechanisms imposed during the normal course of use of the instrument, constant tuning may be required, even during the course of a single performance. The need for constant tuning may disrupt the flow of a performance and is a distraction for the musician.
Automatic tuners for guitars are well known in the art. Most are built into a guitar or require major modification to retrofit into a guitar and consist of a sensor for sensing the pitch of a string and a means for tensioning the string to achieve the proper tension.
Such a system is described in U.S. Pat. No. 6,437,226, issued Aug. 20, 2002 to Oudshoorn, et al. The patent describes system wherein a signal is induced onto a string under tension by a linear displacement motor. The resonance signal generated by the string is picked up by a transducer, converted to a digital signal and analyzed by a microprocessor. The motors then tension or slacken the string in response to the analysis to achieve the proper tuning.
Another such system is sold by Tronical, GmbH of Hamburg, Germany. The Tronical system requires that the musician strum the strings of the instrument to generate a test frequency, which is then analyzed by a microprocessor. The strings are tensioned or slackened by machine heads which are driven by servo motors.
Both the Oudshoorn system and the Tronical system are capable of tuning a guitar, regardless of how far out of tune. Such systems, however, not only are expensive, but have the drawback of requiring permanent installation in a guitar. Therefore, it would be desirable to have a device for keeping a stringed instrument in tune that could be used with any instrument, without the requirement of major modification to the guitar for permanent installation.
The present invention is a retro-fit device that may be used with any stringed instrument having a neck, such as a guitar, banjo, bass or violin. The device is not meant to perform the function of tuning the instrument from scratch, but instead is designed to maintain the instrument in tune after it has been hand-tuned, such as during the course of a performance.
The device consists of a mechanical portion that is attached to the neck of the instrument, much like a capo. The device has built-in sensors to pick up the frequency of a string and a microprocessor to determine when the strings have drifted from their tuned frequencies. The strings may then be “micro-tuned” by a series of cams which may be rotated to further tension or slacken each of the strings.
The device is completely self-contained and battery-powered, and has the advantages over the prior art systems of relatively low cost and portability. The device may quickly be attached and removed from the neck of the instrument.
a) is a top view of a guitar having the device attached thereto.
b) is a side view of a guitar having the device attached thereto.
a) shows a to view of a sub-assembly of the device
b) shows a side view of a sub-assembly of the device.
The invention herein described may be used with any stringed instrument having a neck defining a fretboard. The example used to show the embodiments of the invention utilize a guitar for explanation purposes only. This is not meant to limit the invention in any way. In addition, the device is meant to be compatible with guitars of all configurations, including 6 and 12 string varieties, as well as those guitars having all machine heads on one side of the headstock or divided between both sides of the headstock.
The device is preferably attached to the guitar like a capo, via a hinged clasp mechanism secured by a latch. The bottom brace of the clasp engages the rear of the headstock 52 or fretboard 50 of the guitar opposite the strings, while the top brace consists of the main body of the device. Preferably, the bottom brace is lined with a scratch-resistant material, such as rubber, neoprene or felt to prevent scratching the guitar, while still providing enough gripping power to keep the device securely fastened in place.
a) and 1(b) show top and side views respectively of the tuning device 100 mounted on a guitar in the preferred position. Tuning device 100 preferably sits between nut 107 and the first machine head 70 on headstock 52 of the guitar, with felt pad 106 resting on nut 107.
The body of tuning device 100 consists of a subassembly, shown in
With reference now to
Cams 110 may be driven by a driving device (not shown), such as a motor, a solenoid, or a servo, that may generate a mechanical, electromechanical, pneumatic or hydraulic force upon the pins to drive them in direction 109. Any means of performing this function well known in the art may be used for this purpose.
In an alternate embodiment of the invention, cams 110 may be eliminated and pins 108 may be caused to press directly upon strings 60 of the guitar. In such a case, pins 108 may be spring loaded such as to be forced in the direction opposite direction 109.
With respect to both embodiments shown in
A third embodiment of the invention is shown in
Preferably, as shown in
In an alternate to embodiment 3, strings 60 could be wound multiple times around pins 108, such as to eliminate the need for machine heads 70. In some cases, entire headstock 52 could be eliminated. In this embodiment, pins 108 may take on a concave outer profile, such as to provide room for multiple windings of string 60 around pin 108. In addition, pins 108 may define a hole therein to accept the end of string 60. In this alternate embodiment, the guitar could become a completely self-tuning instrument, being able to tune to different pre-programmed ranges.
Also included as part of the invention, but not shown in the drawings, is a means of detecting the frequency of strings 60 as they are strummed by the musician. This means will likely consist of a plurality of audio input transducers which will pick up an analog signal from each of the strings. The analog signal would likely be converted to a digital signal via an analog to digital converter and then analyzed by either a programmed microprocessor or a specialized circuit capable of analyzing the received audio input and determining if the string needs to be retensioned to bring it back into tune.
In another aspect of the invention, the device cold be outfitted with a wireless transceiver such that a signal picked up by sensors from one or more of the strings could be sent wirelessly to a base station for amplification or processing, or may be supplied to a computer as a MIDI signal.
In operation, tuning device 100 would be initialized by zeroing the cams, such that the cams are deflected half way against the strings, or, as in the third embodiment, partially twisted around each of the pins. The guitar is then manually tuned utilizing machine heads 70 for each string in the normal manner. After a period of use, the guitar may have drifted out of tune. To have tuning device 100 perform the micro tuning adjustments to the strings to bring the instrument back into tune, the strings may be strummed either one at a time or in series while alerting tuning device 100 that a tuning operation has begun by, for example, depressing a button on the device.
It is also contemplated that tuning device 100 may assist the musician in the manual tuning of the guitar by providing an indication that each of the strings is sharp, flat or tuned to the correct frequency by providing some form of feedback to the musician, such as a light or series of lights which indicate if the string is sharp, flat or properly tuned.
Although the invention is shown having pins pushing against the cams to rotate them, it is contemplated that other means of rotating the cams could be used such as a direct drive of the cams with a servo providing a rotational force or a force exerted through a series of gears such as to provide rotational movement in both directions of the cams, thus allowing the pins to be eliminated. In addition, it is possible that the driver or servo mechanism could sit higher on the headstock than the rest of the device, such as between the machine heads, and be connected to the cams via a linkage.
The device is contemplated to be battery powered, with the batteries likely resident in the bottom brace of the device. It is also contemplated that the frequency detection circuitry and mechanical driver portions be located within the top portion 102 of the device, but in certain configurations, could also be located in the bottom brace, and thus be resident on the underside of fretboard 52 of the guitar and be linked via mechanical linkage to the cams.
