JPH0742951U - Automatic tuning device for stringed instruments - Google Patents

Abstract

(57) [Summary] [Purpose] A string instrument having a plurality of strings and a plurality of string winding knobs 4 around which the strings are respectively wound can be mounted as needed and automatically tune. An object of the present invention is to provide an automatic string tuning device 10 capable of performing the above. [Structure] A case 12 which can be detachably fixed to a portion of a stringed instrument where a string winding knob 4 is provided, and a frequency of a string to be tuned is input, and the input frequency is a preset correct frequency of the string. Output control circuit 70 that outputs a predetermined electric signal until reaching a temperature of at least one, and at least one motor 24 that is supported by the case 12 and that is driven to rotate forward and backward in response to the output electric signal from the output control circuit 70; And a rotational drive force transmission mechanism 30 for decelerating and transmitting the rotational drive force of the motor 24 to the string winding knob 4 around which the string to be tuned is wound. The force transmission mechanism 30 has a clamp 48 that is movable in the axial direction of the string winding knob 4 around which the string to be tuned is wound and that can be fitted into the knob 4 and rotated.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an automatic stringing device for a stringed instrument, and more particularly to an automatic stringing device particularly suitable for use in a Taisho koto.

[0002]

[Prior art]

 Stringed instruments with multiple strings, such as guitars, violins, and Taisho koto, require those strings to be precisely tuned to a predetermined chord in order to produce the correct sound. Especially when many players play the same song with the same instrument, it is necessary that all the instruments are tuned correctly. However, in tuning a stringed instrument like this, it is necessary to accurately recognize the pitch of the sound and then fine-tune the string winding knob to match the correct sound by hand. This is a difficult task for a person with a weak pitch.

Therefore, various devices for tuning a stringed instrument have been proposed. For example, the original frequency of the sound of each string is set on the scale beforehand, the frequency when the string to be tuned is played is displayed with a pointer, and the pointer indicates the original frequency of the string. There is a tuning device that indicates that the string has been tuned correctly when it matches the height.

However, this kind of device merely indicates whether or not the pitch, that is, the frequency of the string to be tuned matches the frequency of the chord that the string originally should have. Therefore, in order to tune correctly with this device, while watching the swing of the pointer while playing the string with one hand, use the string winding knob on which the string is wound so that the swing of the pointer matches the reference scale. Fine adjustment work is required. This kind of fine adjustment of the string knob while watching the deflection of the pointer is difficult for elderly beginners, and even if it can be done, it takes a long time.

In particular, the Taisho koto is a musical instrument for the masses and is often learned by the elderly. Therefore, many people cannot tune well with a string tuning device using such a display with a deflection of the pointer. Moreover, since many players play the same piece of music when performing, all kotos must be tuned accurately. Is actually spent.

In view of such a problem, some automatic string tuning devices capable of automatically tuning the strings of a stringed instrument have been proposed. For example, the device described in Japanese Patent Laid-Open No. 56-32185 is known. ing.

In this device, a reference frequency is set in advance, the motor is rotated while the string is being played so that the frequency of the string is synchronized with the reference frequency, and the rotation of the motor is reduced by a speed reduction mechanism. The winder is installed in the winder, and the winder directly winds or loosens the string, thereby adjusting the tension of the string.

However, in this device, as described above, the strings are directly wound or loosened through the winder by the rotation of the motor, and the motor and the winder are built in the main body of the stringed instrument. Incorporating this kind of tuning mechanism inside the musical instrument not only increases the cost of the musical instrument, but is a mechanism that is not necessary for those who can tune themselves, thus limiting the audience for the instrument. It will be. Also, such tuning work is usually required before starting playing the instrument, and once the strings have been set correctly, it is not necessary to equip the instrument with such a tuning device. Wear. Therefore, there is a demand for an automatic tuning device that can be detachably attached to the instrument body that can be used only when necessary, that is, only during the tuning work before starting playing the instrument.

[0009]

[Problems to be solved by the device]

 The present invention has been made in view of the above problems, and its main purpose is to provide an automatic tuning device that can be mounted on a stringed instrument and used only when tuning.

Another object of the present invention is to provide an automatic string tuning device particularly suitable for tuning a Taisho koto, which can be shared by a plurality of Taisho kotos.

Further, another object of the present invention is to provide an automatic tuning device that can be automatically set in a musical instrument regardless of the direction of rotation of the string winding knob during tuning.

[0012]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention can be installed as needed to a stringed instrument having a plurality of strings and a plurality of string winding knobs around which the strings are respectively wound. It is an automatic tuning device that can be tuned dynamically, and a case that can be detachably fixed to the part of the stringed instrument where the string winding knob is provided, and the frequency of the string to be tuned is input. A frequency detection / output control circuit that outputs a predetermined electric signal until the frequency reaches a preset correct frequency of the string, and a forward / reverse operation depending on the output electric signal from the output control circuit, which is supported by the case. At least one motor that is rotationally driven, and a rotational drive force transmission device that is supported by the case and that decelerates and transmits the rotational drive force of the motor to a string winding knob around which the string to be tuned is wound. The rotary drive force transmission mechanism is a clamp that is movable in the axial direction of a string winding knob around which a string to be tuned is wound and that can be rotated by fitting to the knob. It is characterized by having.

As described in claim 2, the clamp preferably has a groove portion into which the string winding knob fits, the first position where the groove portion fits into the string winding knob, and the string It is configured to be movable between a second position that is axially above the winding knob.

The clamp may preferably be a U-shaped member having a single groove into which the string knob can be fitted, as described in claim 3. Further, as described in claim 4, it is possible to adopt a configuration in which grooves into which the string knobs can be fitted are provided so as to intersect in an X shape.

Further, as described in claim 5, the clamp portion is biased by the biasing means from the second position toward the first position, and moves from the second position to the first position. It is also possible to perform the automatic tuning operation after this.

Further, as described in claim 6, when it is detected that the clamp is at the second position when the automatic tuning device is set on the stringed instrument, the motor associated with the clamp is set. Means can be provided to drive the clamp to rotate it to a position where it can be mated with the corresponding string knob.

[0017]

According to the automatic string tuning device of the present invention, the motor and the string for which the rotational driving force of the motor is to be tuned are provided in the case that can be detachably fixed to the part of the stringed instrument where the string winding knob is provided. A rotary driving force transmission mechanism for decelerating and transmitting the rotation is supported by the wound winding knob. This case is set in advance on a predetermined part of the musical instrument, and the clamp provided in this rotary drive force transmission mechanism is set on the corresponding string winding knob. In this state, when you hit the string to be tuned, the frequency of the string is input to the frequency detection / output control circuit and the motor is rotated until it matches the preset reference frequency. The rotation of the motor is transmitted to the string winding knob through the clamp of the rotary drive force transmission mechanism, and the string winding knob rotates until the string wound thereabout reaches a correct sound.

[0018]

【Example】

 Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of an automatic stringing device according to the present invention, in which reference numeral 2 denotes a string winding knob mounting portion of a pillow portion of a Taisho koto on which a string is adjusted by the automatic stringing device. The six string winding knobs 4 are divided into left and right three pieces and are arranged at predetermined intervals. A string (not shown) is wound around each of the string winding knobs 4.

The automatic string tuning device 10 includes a case 12 that can be detachably fixed to the string winding knob mounting portion 4 of the Taisho koto. The case 12 has a pair of U-shaped support frames 14 and 16 provided at intervals. Each of the support frames 14 and 16 is composed of a pair of leg portions 14a, 14b, 16a and 16b and connecting portions 14c and 16c for connecting one ends thereof. These supporting frames 14 and 16 are connected to each other by connecting members 18a and 18b at the corners formed by the legs and the connecting portions, and form a box-shaped frame whose lower side is open as a whole.

The support frames 14 and 16 and the connecting members 18a and 18b are preferably formed of a thin plate metal such as aluminum or plastic, and have appropriate flexibility. The connecting portions 14c and 16c of the supporting frames 14 and 16 are formed to be slightly shorter than the width of the string winding knob attachment portion 2. As a result, in this case 12, as shown in FIG. 1, the string winding knob mounting portion 4 is attached to the string winding knob mounting portion 2 of the Taisho koto between the leg portions 14a, 14b, 16a, 16b of the support frames 14 and 16. It can be attached by sandwiching it from both sides. With the structure of the support frames 14 and 16 as described above, a sufficient holding force to withstand the rotation of the motor described later is generated when the support frame is mounted on the Taisho harp, and it is possible to cope with a slight dimensional difference due to a difference in model. it can. Although the case 12 is shown only by a frame in the drawings, it is actually formed so as to cover the outside with a panel or the like to form a box body. Further, instead of the frame having such a frame structure, a plate-shaped member bent to have a U-shaped cross section may be used as a case. Even when the case is constructed in this way, it is necessary to ensure that sufficient holding force is generated at both ends when it is attached to the Taisho koto.

An upper support plate 18 is installed on the connecting portions 14c and 16c of the support frames 14 and 16. Long holes 19a and 19b extending in the width direction of the Taisho harp are formed at both ends of the upper support plate, and the support frames 14 and 16 are attached to the support frames 14 and 16 through the screws 20a and 20b inserted into the long holes 19a and 19b. It is installed. As a result, the upper support plate 18 is configured to be movable in the width direction of the Taisho koto by the length of the long holes 19a and 19b by adjusting the screws 20a and 20b.

A lower support plate 22 is provided below the upper support plate via a spacer 21. Motors 24 and 26 are attached to the lower side of the lower support plate 22. As shown in FIG. 2, the motors 24 and 26 are mounted so that the rotary shafts 24a and 26a respectively project into the space between the upper and lower support plates 18 and 22. Pinion gears 24b and 26b are attached to the rotary shafts 24a and 26a of these motors.

The rotation of the motor 24 is decelerated and transmitted to the string winding knob 4 via the rotational driving force transmission mechanism 30. The rotational driving force transmission mechanism 30 includes a speed reducing mechanism 32 including a plurality of gears as shown in FIG. 2, and a string winding knob adjusting mechanism 38 that rotates at a low speed via the speed reducing mechanism 32.

That is, this reduction mechanism 32 is rotatable between two shafts 34 and 36 arranged between the upper and lower support plates 18 and 22 in the same direction as the rotation shaft of the motor 24. And gears 34a, 34b, 36a, 36b, respectively, which are operably attached. More specifically, the pinion gear 24b of the motor 24 is engaged with the lower first gear 34a of the shaft 34, and the first gear 36a of the shaft 36 is connected to the gear 34a, and the first gear 36a of the shaft 36 is connected to the gear 36a. The second gear 34b of the shaft 34 is engaged with the second gear 36b of the shaft 36, and the rotation of the motor 24 is decelerated and transmitted.

On the other hand, the string knob control mechanism 38 includes a hollow inner cylinder 42 rotatably supported by bearings 40 a and 40 b provided at corresponding positions of the upper and lower support plates 18 and 22, and the inner cylinder 42. A hollow outer cylinder 44, which is partially overlapped and fixed to the outside of the lower projecting portion of the lower support plate 22 of 42, and a string knob clamp member 46 provided below the outer cylinder 44. Is equipped with.

A gear 42 a that engages with the final gear 36 b of the speed reduction mechanism 32 is attached to the inner cylinder 42 between the upper and lower support plates 18 and 22, and is rotated with the rotation of the motor 24. Is configured. The gear ratio of the pinion gear 24a, the gears 34a, 34b, 36a, 36b of the reduction mechanism 32 and the gear 42a attached to the inner cylinder 42 is preferably such that the inner cylinder 42 rotates about 1 to 4 times per second. It is desirable to set so that the rotation of the motor is decelerated and transmitted as described above.

As shown in FIGS. 3 and 4A and 4B, the clamp member 46 includes a clamp rod 47 slidably inserted in a hollow portion of the outer cylinder 44, and the rod. And a string knob clamp 48 attached to the tip of the. A coil spring 50 for urging the rod 47 downward is arranged between the upper end surface of the rod 47 inserted into the outer cylinder 44 and the end surface of the inner cylinder 42 inserted from the upper portion of the outer cylinder. Has been done. On the other hand, the outer cylinder 44 is formed with an elongated hole 44a extending in the axial direction. The positioning regulating pin 47a fixed to the tip of the rod 47 projects from the elongated hole 44a, and the positioning regulating pin 47a extends into the elongated hole 44a. The downward movement position of the rod 47 is regulated by engaging with the lower edge of the rod 47.

As shown in detail in FIGS. 5 (A), (B) and (C), the string knob clamp 48 is bent in a U-shape having a groove to be fitted into the string knob 4 of Taisho Koto. And a lower end of the rod 47 is fixed to an upper end surface of the clamp 48. With these configurations, the clamp 48 is configured to be movable between the first position (FIG. 4 (A)) that engages with the knob 4 and the second position (FIG. 4 (B)) above the knob. Has been done.

Further, as shown in FIG. 4, the upper end surface of the clamp rod 47 on the side opposite to the clamp 48 penetrates the coil spring 50 and the inner cylinder 42 arranged in the outer cylinder 44. The switch operating rod 52, which is extended, is fixed so that the limit switch 54 provided on the upper surface of the upper support plate 18 is turned on and off as the clamp 48 moves between the first position and the second position. Has become. That is, as shown in FIG. 4 (A), the clamp rod 47 is constantly urged downward by the spring 50 to be located in the first position, and at this time, the switch operating rod 52 is pressed. Turns off the limit switch 54. On the other hand, as shown in FIG. 4 (B), when the automatic tuning device is attached to the Taisho koto, the direction of the groove of the clamp 48 does not match the direction of rotation of the string winding knob 4, and the upper side of the knob 4 If it seems that the user has got on it, the clamp 48 moves from the first position to the second position against the biasing force of the coil spring 50. In this case, the switch operating rod 52 turns on the limit switch 54. As a result, it can be detected that the clamp 48 is not normally fitted to the knob 4. When it is detected that the clamp 48 is not properly fitted to the string winding knob 4 when the automatic tuning device is set on the Taisho koto, the clamp 48 is connected to the clamp 48 through a control circuit described later. The associated motor 24 is driven to rotate the clamp 48. With this rotation, when the direction of the groove of the clamp 48 matches the direction of the string winding knob 4, the clamp 48 moves from the second position to the first position by the urging force of the spring 50, and the limit switch 54 is turned on. It is turned off to indicate that the clamp 48 is normally fitted to the knob 4, and the driving of the motor 24 is stopped. In this way, after it is confirmed that the clamp 48 has been set normally, the automatic tuning operation described later is performed.

FIG. 6 shows a modified example of the clamp 48, which has an X-shaped engaging groove. According to this structure, it can be fitted in the string knob 4 by rotating about 45 °, and the clamp can be easily set. Also, with such a configuration, the area under the clamp is wider than that of the U-shaped clamp described above, and when the automatic tuning device is set on the Taisho koto, the position of the string tuning knob and the normal position of both of them are normal. It is possible to prevent the situation where the vehicle is mistakenly placed in the first position even though it is not fitted in. It goes without saying that, in addition to the X-shaped groove, three or more engaging grooves may intersect with each other.

Although only two motors and rotational driving force transmission mechanisms are shown in the above-described embodiments, it is preferable to provide them in correspondence with the number and position of the string winding knobs 4. Immediately, it is preferable that each of the string winding knobs 4 is provided with an individual motor and a rotational driving force transmission mechanism, and each of the string winding knobs 4 is individually adjusted. Further, the rotational driving force transmitting mechanism may be provided in the number corresponding to each of the string winding knobs 4, and only the motor may be shared. In this case, unlike the above embodiment, a switching mechanism for arbitrarily switching to which rotary drive transmission mechanism the rotation of the motor is transmitted is provided.

Further, in the above-described embodiment, when the clamp 48 is not properly fitted to the string winding knob 4, the limit switch 54 detects the abnormality, but such a detection mechanism is not provided. When setting the automatic stringing device to the Taisho koto, hold each clamp in the second position by the attraction force of the magnet etc., set the rotation position of the string winding knob manually, then release the attraction by the magnet and set each clamp. It may be moved to the first position and fitted to the string knob 4.

Next, the frequency detection / output control circuit of the automatic tuning device according to the present invention will be described.

FIG. 7 shows a basic configuration of the frequency detection / output control circuit 70 according to an embodiment of the present invention. Reference numeral 72 in the figure is a voice-voltage conversion circuit, which is used to input a voice, that is, a sound generated when a string is played, by a microphone or the like and convert it into an electrical signal. The signal from the voice-voltage conversion circuit 72 is input to the input level detection circuit 74, where the volume of the input sound is detected based on this input signal. It outputs Hi, and otherwise outputs Low. This prevents the device from malfunctioning due to external noise. The input signal is also input to the frequency detection circuit 76, where it is determined whether or not the frequency of the input signal is within a constant frequency range, that is, the pitch of the sound is detected and If it is present, Hi is output. This is to prevent a malfunction when a string other than the one to be tuned is mistakenly played.

The outputs from the input level detection circuit 74 and the frequency detection circuit 76 are input to the switch SW1 via the AND circuit 77. As a result, when the signal input to the input level detection circuit 74 is above a certain level and the frequency of the input signal is within a certain range, that is, it is confirmed that the string to be tuned has been played. If so, there is an output from the AND circuit 77 and the switch SW1 is turned on.

On the other hand, the input signal is also input to the frequency comparison circuit 78, where the frequency (fi) of the input signal and the frequency (f0) at which the string is to be tuned, that is, the tone that the string should originally have. It is compared with the frequency (comparison frequency / reference frequency) and the difference is output as a voltage value. That is, a positive voltage is output when fi> f0, and a negative voltage is output when fi <f0. The output from the frequency comparison circuit 78 is output to the tuning end detection circuit 80. The tuning end detection circuit 80 is configured to output Low when it detects that tuning has ended, that is, fi = f0, and outputs Hi otherwise. . The output of the tuning end detection circuit 80 is input to the switch SW2. The switch SW2 is turned off when the output from the tuning end detection circuit 80 is Low, that is, when the frequency of the string to be tuned matches the reference frequency. The switch SW2 is connected to the motor 24 via the motor driver 82.

According to the above system, when a string is played in order to tune, a Hi signal is output from both the input level detection circuit 74 and the frequency detection circuit 76, and SW1 is turned on via the AND circuit 77. In this state, when the frequency of the sound of the string to be tuned does not match the reference frequency, SW2 is ON, and the motor 24 is controlled by the motor driver 82 so that the frequency of the string becomes the comparison frequency. Drive in the same direction. That is, when fi> f0 (when the input frequency is higher than the comparison frequency-when the string is too tight), the motor 24 is rotated in the direction of decreasing fi (in the direction of loosening the string). On the other hand, when fi <f0 (when the input frequency is lower than the comparison frequency-when the string is stretched loosely), the motor 24 is rotated in the direction in which fi increases (in the direction in which the string is stretched strongly). Then, when it is confirmed by the frequency comparison circuit 78 that fi = f 0 is satisfied (when the height of the string to be tuned matches the comparison frequency-when the tuning is finished), The SW2 output from the tuning end detection circuit 80 is turned off, and the rotation of the motor 24 is stopped.

If the above steps are performed for each string winding knob, all strings can be tuned correctly.

FIG. 8 is a block diagram of the frequency detection / output control circuit 90 of the embodiment according to the present invention. Since it is basically the same as the basic system described with reference to FIG. 7, the same parts will not be described. By giving the same reference numerals, detailed description will be omitted.

The difference between the frequency detection / output control circuit 90 and the basic system of FIG. 7 described above is that a reference frequency setting circuit 92, a frequency display device 94, and a comparison frequency adjusting circuit 96 are provided. These are, for example, when the frequency of the sound that each string should originally have is set as the reference frequency according to the pure articulatory scale, and then the reference frequency cannot be used as it is as the comparison frequency due to differences in the model or style. The reference frequency is corrected to set the comparison frequency f0.

That is, the reference frequency setting circuit 92 outputs the reference frequency, that is, the frequency (fref) of the original sound of each string to be tuned. The output (fref) from the reference frequency setting circuit 92 is input to the frequency comparison circuit 78 via SW11. That is, this SW11 is designed to switch between the A contact side and the B contact side. When it is connected to the A contact side, the signal from the audio-voltage conversion circuit 72 is the same as in the basic system. That is, when a signal corresponding to the sound of the string to be tuned is input to the frequency comparison circuit 78 and connected to the B contact side, the output signal (fref) from the reference frequency setting circuit 92 is input. It is supposed to be done. On the other hand, from the comparison frequency adjusting circuit 96, the comparison frequency (f0) obtained by correcting the reference frequency is input and compared with the reference frequency fref. In this case, the output V1 of the frequency comparison circuit 78 becomes a negative voltage when f0 <fref and a positive voltage when f0> fref.

The output from the frequency comparison circuit 78 is output to the frequency display unit 94 via the switch SW12 and displayed on the meter (not shown) of the operation panel, and the comparison frequency is set based on this meter. . That is, the switch SW12 is switched between the A contact side and the B contact side, and when connected to the B contact side, -V1 is input to the frequency display unit 94. The frequency display section 94 displays a minus sign when fref> f0 and a plus sign when fref <f0. Then, while observing this display, the setting level of the frequency comparison circuit 78 is adjusted. In this case, the range of the detection frequency of the frequency detection circuit 76 is similarly adjusted by the signal from the comparison frequency adjustment circuit 96, and as a result, the detection frequency range is also changed in accordance with f0 to prevent a malfunction in the tuning operation.

The comparison frequency f0 is set prior to the tuning operation, and the switch 13 connected between the output side of the frequency comparison circuit 78 and the switch 1 is set between these settings. Is switched to the B contact side, so that the motor 24 does not rotate. The arrows shown by dotted lines in the figure indicate that these switches SW11, SW12, and SW13 operate in conjunction with each other.

The frequency detection / output control circuit 90 performs the same operation when tuning each string. When a plurality of motors are provided, the output of each motor is switched via the motor driver 82. Furthermore, when the direction of the groove of the clamp 48 does not coincide with the string winding knob 4 when the above-mentioned tuning device is set and the clamp is in the second position, the motor 24 is driven based on the signal from the limit switch 54. Is driven. It should be noted that a circuit for this purpose is not shown in the drawing because a known circuit is used. The above frequency detection / output control circuit 90 can be preferably configured to be housed in the case.

The method of use and the operation of the automatic tuning device according to the present invention having the above structure will be described.

First, the automatic tuning device 10 is set on the string knob mounting portion of Taisho Koto. At this time, each clamp 48 is positioned so as to coincide with the position of the corresponding string winding knob 4, and the stringer knob mounting portion is clamped from both sides by the customer portions 14a, 14b, 16a, 16b of the supporting frames 14, 16. And set. In this state, if the rotation angle of the winding knob 4 and the groove direction of the clamp 48 do not match, the clamp 48 moves to the second position shown in FIG. 4B, the limit switch 54 is turned on, and the clamp 48 is turned on. Indicates that it is not set correctly on the string knob 4. When such a state is detected, the motor 24 associated with the string winding knob 4 is driven to rotate the clamp 48. When the direction of the groove of the clamp 48 coincides with that of the string knob 4, the clamp 48 moves to the first position by the urging force of the spring 50, and the limit switch 54 also turns off accordingly, indicating that the clamp 48 is set normally. , The motor 24 also stops.

In this state, the comparison frequency f0 is set as described above. In this case, if the reference frequency fref is used as it is as the comparison frequency, this step can be omitted.

Next, the microphone is set, the string to be tuned is played, and the current sound of the string is input to the voice-voltage conversion circuit 72. Here, as described above, the input level detection circuit 74 prevents malfunction due to external noise, and the frequency detection circuit 76 prevents malfunction when another string is accidentally played. It is supposed to be done. When it is confirmed by these circuits that the sound is a string to be tuned, the switch SW1 is turned on, the motor 24 is rotated via the motor driver 82, and the rotation driving force transmission mechanism 30 and the clamp 48 are rotated. Tighten or loosen the winding knob 4 via. In this state, continue to play the string, and if it is confirmed that the frequency of the string matches the comparison frequency f0, the switch SW2 is turned off by the signal from the tuning end detection circuit 80, and the rotation of the motor 24 is started. Stops and the tuning operation ends.

When the motor and the clamp 48 are provided corresponding to each of the string winding knobs 4, the same operation is performed on the remaining strings while maintaining the installed state of the case 12. On the other hand, when only two motors and clamps are provided as shown in Fig. 1, in order to adjust the remaining string winding knobs, the fixed position of the case with respect to the string winding knob mounting portion is appropriately moved, and those string winding knobs are moved. Tune the strings wound on the knob. In some cases, the screw 20 engaged with the long hole 19 of the upper support plate 18 is loosened, and the support plate 18 is slid to be aligned with the position of the string knob 4. By performing this kind of work, all strings of Taisho Koto can be tuned automatically. Further, unlike the above embodiment, the clamp 48 may be manually fitted to each of the string knobs 4. In this case, the direction of the knob 4 may be adjusted in advance to the direction of the groove of the clamp, and in such a case, the detection mechanism such as the limit switch 54 is unnecessary.

Although the above embodiments have been described with respect to the case where the automatic tuning device according to the present invention is used in a Taisho koto, the present invention can be applied to other stringed instruments such as a guitar and a violin. . In such a case, of course, the shape of the case and the position of the clamp will be modified to match the position of the string knob of the target instrument.

[0051]

[Effect of device]

 According to the above-described automatic string tuning apparatus for a stringed instrument of the present invention, it can be used as needed for a stringed instrument that requires tuning, and if the string is simply played, the correct tuning string is automatically obtained. Because it can be done, it is very practical. In particular, when using the automatic tuning device when playing the same piece of music with multiple musical instruments, there is no individual difference in the articulation and uniform tuning is possible.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of an automatic tuning device according to the present invention.

FIG. 2 is a cross-sectional view showing a motor and a rotational driving force transmission mechanism of the above embodiment.

FIG. 3 is a front view showing a configuration of a string winding knob adjusting mechanism of the above embodiment.

FIG. 4 is a cross-sectional view showing an operating state of the string winding knob adjusting mechanism of the above embodiment, where FIG. 4 (A) shows the clamp in the first position and FIG. 4 (B) shows the clamp in the second position. The case is shown.

5 is a diagram showing the structure of the clamp, FIG.
Is a front view, FIG. 5 (B) is a side view, and FIG. 5 (C) is a plan view.

FIG. 6 is a perspective view showing another modified example of the clamp.

FIG. 7 is a block diagram showing a basic system of a frequency detection / output control circuit of the automatic tuning device according to the present invention.

FIG. 8 is a block diagram showing a system of a frequency detection / output control circuit of the automatic tuning device according to the present invention.

[Explanation of symbols]

 2 String winding knob mounting portion 4 String winding knob 10 Automatic tuning device 12 Case 14, 16 Support frame 14a, 14b, 16a, 16b Leg portion 14c, 16c Connecting portion 18 Upper supporting plate 18a, 18b Connecting member 19a, 19b Long hole 20a, 20b Screw 21 Spacer 22 Lower support plate 24,26 Motor 24a, 26a Rotation shaft 24b, 26b Pinion gear 30 Rotational driving force transmission mechanism 32 Reduction mechanism 34, 36 Shaft 34a, 34b, 36a, 36b Gear 38 String winding knob adjustment mechanism 40a, 40b Bearing 42 Inner cylinder 42a Gear 44 Outer cylinder 44a Long hole 46 Knob clamp member 47 Clamp rod 47a Positioning regulation pin 48 String winding knob clamp 50 Coil spring 52 Switch operating rod 54 Limit switch 70 Frequency detection / output control circuit 72 voice-voltage conversion circuit 74 input level detection circuit 76 frequency detection circuit 77 AND circuit 78 frequency comparison circuit 80 tuning end detection circuit 82 motor driver 90 frequency detection / output control circuit 92 reference frequency setting circuit 94 frequency display device 96 comparison frequency Adjustment circuit

Claims (6)

[Scope of utility model registration request] 1. An automatic tuning which can be mounted as needed on a stringed instrument having a plurality of strings and a plurality of string winding knobs around which the strings are respectively wound, and which can automatically tune the strings. A device, wherein the automatic tuning device has a case that can be detachably fixed to a portion of a stringed instrument where a string winding knob is provided, a frequency of a string to be tuned is input, and the input frequency is preset. Frequency detection / output control circuit that outputs a predetermined electric signal until the correct frequency of the string is reached, and forward / reverse rotation drive supported by the case according to the output electric signal from the frequency detection / output control circuit. At least one motor, and a rotational driving force transmission device for decelerating and transmitting the rotational driving force of the motor to the string winding knob around which the string to be tuned is wound. The rotary drive force transmission mechanism includes a clamp that is movable in the axial direction of the string winding knob around which the string to be tuned is wound and that can be rotated by fitting to the string winding knob. An automatic string tuning device for a stringed instrument, characterized by having. 2. The clamp has a groove portion into which the string winding knob fits, and the groove portion fits into the string winding knob.
The automatic stringing device according to claim 1, wherein the automatic stringing device is configured to be movable between a position and a second position that is axially above the string knob. 3. The automatic stringing device according to claim 2, wherein the clamp is a U-shaped member having a single groove into which a string knob can be fitted. 4. The automatic stringing apparatus according to claim 2, wherein the clamp is provided with a groove into which a string winding knob can be fitted so as to intersect in an X shape. 5. The clamp portion is urged by an urging means from the second position toward the first position, and an automatic tuning operation is performed after moving from the second position to the first position. The automatic tuning device according to claim 2, wherein 6. If the clamp is detected to be in the second position when the automatic tuning device is mounted on a stringed instrument, the motor associated with the clamp is driven to respond to the clamp. 6. The automatic tuning device according to claim 2, further comprising means for rotating the string winding knob to a position where it can be fitted.