JP2022001909A - Opening amount adjustment device - Google Patents

Abstract

To provide an opening amount adjustment device capable of easily adjusting an opening amount of a sound hole.SOLUTION: An opening amount adjustment device 10 is provided, for example, at a sound hole for emitting sound and opened at a stringed instrument such as a guitar, and includes: a movable member 12 moving so as to change the opening amount of an opening part of the sound hole; and an operation member 13 for operating the movable member. Thereby, the adjustment of sound volume, which has been conventionally difficult, can be performed easily, and the sound volume and tone can be changed during musical performance.SELECTED DRAWING: Figure 2

Description

The present invention relates to an opening amount adjusting device provided in a sound hole.

A stringed instrument such as a guitar is provided with an opening called a sound hole, and the volume emitted from this sound hole is often higher than the volume emitted from other parts. Further, a percussion instrument such as a cajon may also be provided with a sound hole. Further, not only musical instruments but also speakers may be provided with sound holes for the purpose of adjusting sound effects and the like.

Patent Document 1 discloses a lid that reduces the volume during performance by being attached to a sound hole of a guitar.
However, with the lid of Patent Document 1, it was not possible to finely adjust the volume. Also, for example, it was difficult to adjust the volume during a performance.

Japanese Unexamined Patent Publication No. 2008-209871

An object of the present invention is to provide an opening amount adjusting device capable of easily adjusting the opening amount of a sound hole.

The present invention solves the above-mentioned problems by the following solution means. In addition, in order to facilitate understanding, the description will be given with reference numerals corresponding to the embodiments of the present invention, but the present invention is not limited thereto.

The first invention is provided in a sound hole (2) that emits sound, and is provided with a movable member (12, 22, 32) that is provided with a movable member (12, 22, 32) that can change the opening amount of the opening of the sound hole (2). The device (10, 20, 30).

The second invention is the operating member (13, 23, 36, 37) that operates the movable member (12, 22, 32) in the opening amount adjusting device (10, 20, 30) according to the first invention. The opening amount adjusting device (10, 20, 30) is characterized by the above.

A third aspect of the invention is the opening amount adjusting device (30) according to the second invention, wherein the operating members (36, 37) are removable. be.

A fourth aspect of the invention is the opening amount adjusting device (20, 30) according to any one of the first to third inventions, wherein the opening amount adjusting device (20, 30) is an existing sound hole (20, 30). It is an opening amount adjusting device (20, 30) characterized in that it can be retrofitted to 2).

According to the present invention, it is possible to provide an opening amount adjusting device capable of easily adjusting the opening amount of a sound hole.

It is a figure which shows the 1st Embodiment of the guitar 1 using the opening amount adjusting apparatus 10 by this invention. It is a perspective view of the opening amount adjusting apparatus 10 of 1st Embodiment. FIG. 3 is an exploded perspective view of the opening amount adjusting device 10 of the first embodiment as viewed diagonally from the front. FIG. 3 is an exploded perspective view of the opening amount adjusting device 10 of the first embodiment as viewed diagonally from the rear. It is a figure which shows the movable member 12 in a closed state. It is a figure which shows the movable member 12 in the intermediate position between the closed state and the open state. It is a figure which shows the movable member 12 in an open state. It is a perspective view of the opening amount adjusting apparatus 20 of 2nd Embodiment. It is a side view of the opening amount adjusting apparatus 20 of 2nd Embodiment. FIG. 3 is an exploded perspective view of the opening amount adjusting device 20 of the second embodiment as viewed diagonally from the front. FIG. 3 is an exploded perspective view of the opening amount adjusting device 20 of the second embodiment as viewed diagonally from the rear. It is a partial cross-sectional view of the state which attached the opening amount adjusting apparatus 20 of 2nd Embodiment to the sound hole 2 of a guitar 1. It is a figure which shows the movable member 22 in a closed state. It is a figure which shows the movable member 22 in the intermediate position between the closed state and the open state. It is a figure which shows the movable member 22 in an open state. The opening amount adjusting device 20 is detachably attached to and detached from the sound hole 2 by using the magnet M. The opening amount adjusting device 20 is detachably attached to and detached from the sound hole 2 by using the screw B from the front side. The opening amount adjusting device 20 is detachably attached to and detached from the sound hole 2 by using the screw B from the rear side. It is a figure which shows the mounting form which provides the male thread shape 20a corresponding to the size of a sound hole 2 in the opening amount adjusting device 20. It is a perspective view which shows the structure which makes the opening amount adjustment device 20 detachable with respect to a sound hole 2 by the shape which applied the bayonet mount. It is a figure explaining the embodiment which attaches the opening amount adjusting device 20 when the front plate of a guitar is a curved surface. It is a figure which shows the form which the movable member 101 slides and moves. It is a figure which shows the form which the two movable members 102, 103 slide and move. It is a figure which shows the form which the movable member 104 rotates. It is a figure which shows the form which a plurality of louver-shaped movable members 105 rotate. FIG. 3 is an exploded perspective view of the opening amount adjusting device 30 of the third embodiment as viewed diagonally from the front.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings and the like.

(First Embodiment)
FIG. 1 is a diagram showing a first embodiment of a guitar 1 using the opening amount adjusting device 10 according to the present invention.
In addition, each figure shown below including FIG. 1 is a diagram schematically shown, and the size and shape of each part are shown by exaggerating or omitting them as appropriate for easy understanding. ing.
Further, in the following description, specific numerical values, shapes, materials and the like will be described, but these can be changed as appropriate.
In the following description, the front side shown in FIG. 1 will be referred to as the front side, and the opposite side will be referred to as the rear side.

As shown in FIG. 1, the guitar 1 is an acoustic guitar. A sound hole 2 is opened on the front side of the guitar 1, and an opening amount adjusting device 10 is attached to the opening of the sound hole 2. Note that FIG. 1 shows a closed state in which the opening amount adjusting device 10 is completely closed.

FIG. 2 is a perspective view of the opening amount adjusting device 10 of the first embodiment.
FIG. 3 is an exploded perspective view of the opening amount adjusting device 10 of the first embodiment as viewed diagonally from the front.
FIG. 4 is an exploded perspective view of the opening amount adjusting device 10 of the first embodiment as viewed diagonally from the rear.
The opening amount adjusting device 10 of the first embodiment includes a cam member 11, a movable member 12, an operating member 13, and a cover member 14. Each member constituting the opening amount adjusting device 10 can be appropriately made of a material such as resin, metal, wood, etc. However, for example, when a polyacetal resin is used, the slidability can be improved, so that the wear resistance is improved. It is desirable because it is excellent and easy to mold.

The cam member 11 is formed in a substantially annular shape, and a cam groove 11a is provided on the front surface side. In this embodiment, 10 cam grooves 11a are provided, which is the same number as the number of movable members 12 described later.

The movable member 12 is composed of a plate-shaped member having a substantially quadrangular shape, and 10 members having the same shape are provided. A cam pin 12a projects from the rear surface side of the movable member 12. The cam pin 12a is fitted with the cam groove 11a. A guide rib 12b projects from the front surface side of the movable member 12. The guide rib 12b is fitted with the guide groove 13a of the operation member 13 described later. Further, the movable member 12 of the present embodiment is configured to have a thickness of about 2 mm in order to prevent the movable member 12 itself from vibrating and generating an abnormal noise at the time of sounding.

The operation member 13 is formed in a substantially annular shape, and the movable member 12 is arranged so as to be sandwiched between the movable member 12 and the cam member 11. On the rear surface side of the operating member 13, ten guide grooves 13a are provided, which is the same number as the number of movable members 12. Further, the operation knob portion 13b protrudes from the front surface side of the operation member 13 to facilitate the operation. The operation member 13 is rotatable and can be rotated by the operation of the user.

The cover member 14 is formed in a substantially annular shape, and the movable member 12 and the operating member 13 are arranged so as to be sandwiched between the cam member 11. The cover member 14 and the cam member 11 are fixed by screws (not shown).

In the opening amount adjusting device 10 having the above configuration, the joint surface 14a of the cover member 14 is fixed to the inner wall surface of the front plate of the guitar 1 by using an adhesive or double-sided tape.

FIG. 5 is a diagram showing a movable member 12 in a closed state.
FIG. 6 is a diagram showing a movable member 12 at an intermediate position between a closed state and an open state.
FIG. 7 is a diagram showing the movable member 12 in the open state.
It should be noted that FIGS. 5 to 7 show a fluoroscopic form in which a part configuration necessary for explanation is appropriately selected.
When the operating member 13 is operated by the user, the guide groove 13a pushes the guide rib 12b, so that the movable member 12 moves as shown in FIGS. 5 to 7. Since the movement of the movable member 12 is regulated by the guide groove 13a and the cam groove 11a, the movable member 12 can move on a predetermined locus and can move from the open state to the closed state. Further, the user can set the opening amount of the sound hole formed by the movable member 12 to an arbitrary opening amount by stopping the operating member 13 at an arbitrary position.

As described above, in the first embodiment, since the opening amount adjusting device 10 is provided in the sound hole of the guitar 1, the size of the sound hole can be increased, decreased, or closed. You can make a nice tone. In addition, since the opening amount of the sound hole can be changed during the performance, it is possible to realize the expression of the performance for the player and the diversification of the performance technique. When the sound hole is fully opened, the bass is rich and thick, and the overtones and miscellaneous taste of the strings tend to be faint. Also, when the sound hole is fully closed, the sound pressure drops, but it is possible to emit a sound with a strong impact like a musical instrument that originally does not have a sound hole such as biwa. Also, unlike a lid that simply closes a hole, it can not only be fully opened and fully closed, but can also produce a little bass. Therefore, it leads to diversification of tones, expressions, and playing techniques that could not be produced by conventional musical instruments, and can bring new experiences to players and audiences.

(Second Embodiment)
FIG. 8 is a perspective view of the opening amount adjusting device 20 of the second embodiment.
FIG. 9 is a side view of the opening amount adjusting device 20 of the second embodiment.
The opening amount adjusting device 20 of the second embodiment is attached to the sound hole (opening) of the guitar in the same manner as the opening amount adjusting device 10 of the first embodiment. The opening amount adjusting device 10 of the first embodiment has a configuration attached to the inner surface side of the guitar 1, and was attached at the time of manufacturing the guitar 1. On the other hand, the opening amount adjusting device 20 of the second embodiment has a structure that can be attached to and detached from the guitar 1, and is conventionally commercially available for existing guitars (the opening amount adjusting device is not provided). It can be attached to or removed from the sound hole of guitar) 1.

The opening amount adjusting device 20 of the second embodiment basically has the same configuration as that of the first embodiment. Therefore, the same reference numerals are given to the parts that perform the same functions as those of the first embodiment described above, and duplicate description will be omitted as appropriate.

FIG. 10 is an exploded perspective view of the opening amount adjusting device 20 of the second embodiment as viewed diagonally from the front.
FIG. 11 is an exploded perspective view of the opening amount adjusting device 20 of the second embodiment as viewed diagonally from the rear.

The opening amount adjusting device 20 of the second embodiment includes a cam member 21, a movable member 22, an operating member 23, a cover member 24, and a mounting member 25.

The cam member 21 has the same configuration as the cam member 11 of the first embodiment, and includes a cam groove 21a.

The movable member 22 has the same configuration as the movable member 12 of the first embodiment, and 10 members having the same shape are provided. A cam pin 22a projects from the rear surface side of the movable member 22. The cam pin 22a is fitted with the cam groove 21a. A guide rib 22b projects from the front surface side of the movable member 22. The guide rib 22b is fitted with a guide groove 23a of the operation member 23 described later.

The operation member 23 has the same configuration as the operation member 13 of the first embodiment, and is arranged so as to sandwich the movable member 22 with the cam member 21. On the rear surface side of the operating member 23, 10 guide grooves 23a are provided, which is the same number as the number of movable members 22. Further, the operation knob portion 23b protrudes from the front surface side of the operation member 23. The operation member 23 is rotatable and can be rotated by the operation of the user.

The cover member 24 is formed in a substantially annular shape, and the movable member 22 and the operating member 23 are arranged so as to be sandwiched between the cam member 21 and the cover member 24, as in the case of the cover member 14 of the first embodiment. It is a composition. On the other hand, since the opening amount adjusting device 20 of the present embodiment is attached to the sound hole 2 of the guitar 1 afterwards, the front side of the cover member 24 has an appearance that has a sense of unity with the operating member 23, and has a design. I'm raising it.

The mounting member 25 is a member newly provided in the second embodiment. The mounting member 25 is formed in a substantially annular shape, and is fixed to the rear surface of the cam member 21 with an adhesive or the like. Further, the mounting member 25 is made of flexible rubber and has a fin-shaped engaging shape 25a protruding to the rear side.

FIG. 12 is a partial cross-sectional view of a state in which the opening amount adjusting device 20 of the second embodiment is attached to the sound hole 2 of the guitar 1.
The opening amount adjusting device 20 of the second embodiment is attached to the sound hole 2 of the guitar 1 by utilizing the elastic deformation of the engaging shape 25a. The specific shape of the engagement shape 25a, the hardness of the rubber, and the like may be appropriately changed according to the size of the sound hole 2 and the plate thickness around the sound hole 2.
By providing the mounting member 25, the opening amount adjusting device 20 of the second embodiment can be attached to and detached from the existing guitar 1, and the opening amount can be adjusted even in the existing guitar.

FIG. 13 is a diagram showing a movable member 22 in a closed state.
FIG. 14 is a diagram showing a movable member 22 at an intermediate position between a closed state and an open state.
FIG. 15 is a diagram showing a movable member 22 in an open state.
It should be noted that FIGS. 13 to 15 show a fluoroscopic form in which a part configuration necessary for explanation is appropriately selected.
When the operating member 23 is operated by the user, the movable member 22 moves as shown in FIGS. 13 to 15, and the movable member 22 is in the open state to the closed state in the same manner as in the first embodiment. It is possible to move with. Further, the user can set the opening amount of the sound hole formed by the movable member 22 to an arbitrary opening amount by setting the operating member 23 at an arbitrary position.

As described above, in the second embodiment, by providing the mounting member 25, the opening amount adjusting device 20 of the second embodiment can be attached to and detached from the existing guitar 1, and the existing guitar can also be used. It is possible to adjust the opening amount. That is, by attaching the opening amount adjusting device 20 of the second embodiment to an existing acoustic instrument currently distributed in the world market, it leads to diversification of tones, expressions, and playing techniques that cannot be produced by conventional musical instruments, and can be used by players and players. It can bring a new experience to the audience.
Further, the opening amount adjusting device 20 of the second embodiment can be attached to an acoustic guitar currently on the market, regardless of the size of the musical instrument, without requiring a major modification of the musical instrument itself.

(Deformed form of the mounting form of the second embodiment)
In the second embodiment described above, an example in which the opening amount adjusting device 20 is detachable by utilizing the elastic deformation of the rubber of the mounting member 25 has been described. Not limited to this, other forms can be used for the configuration in which the opening amount adjusting device 20 is detachable from the sound hole. Hereinafter, a specific example will be described. In the following description, the opening amount adjusting device 20 will be described, but the opening amount adjusting device 20 is not provided with the mounting member 25, and the form is appropriately changed according to the mounting form. And.

FIG. 16 shows a configuration in which the opening amount adjusting device 20 is detachably attached to and detached from the sound hole 2 by using the magnet M.
The magnet M is arranged on the inner surface side of the guitar 1 through the sound hole 2. The cam member 21 of the opening amount adjusting device 20 is made of iron or the like, or a ferromagnetic material such as iron or a magnet is fixed to the rear surface side of the cam member 21 to open the opening using the magnet M. The amount adjusting device 20 can be attached to and detached from the sound hole 2.

FIG. 17 shows a configuration in which the opening amount adjusting device 20 is detachable from the sound hole 2 by using the screw B from the front side.
FIG. 18 shows a configuration in which the opening amount adjusting device 20 is detachable from the sound hole 2 by using the screw B from the rear side.
As shown in FIG. 17 or FIG. 18, the opening amount adjusting device 20 may be attached to the sound hole 2 by using the screw B. In the case of FIG. 18, in the case of the size of the sound hole 2 where it is difficult to turn the screw B, the screw B with a head so that the screw B can be turned by hand may be used.
Further, the present invention is not limited to the form in which the screw B is fixed by biting into the member around the sound hole 2 as in the above-mentioned example. For example, a through hole is provided in the member around the sound hole 2 and the opening amount is adjusted by bolts and nuts. The device 20 may be sandwiched and fixed.

FIG. 19 is a diagram showing a mounting mode in which the opening amount adjusting device 20 is provided with the male screw shape 20a corresponding to the size of the sound hole 2.
As shown in FIG. 19, by providing the male screw shape 20a corresponding to the size of the sound hole 2 in the opening amount adjusting device 20, the male screw shape 20a is screwed into the sound hole 2 while rotating the entire opening amount adjusting device 20. Therefore, the opening amount adjusting device 20 can be attached to and detached from the sound hole 2. Here, since the members around the sound hole 2 are often relatively hard, it is desirable that the portion of the male screw shape 20a is formed into a tapping screw shape by an elastic body such as rubber. Since the portion of the male screw shape 20a is formed by an elastic body, the rubber follows the hard base material of the diaphragm and can be easily fixed.
It should be noted that the sound hole 2 may be screwed into the male screw shape 20a by performing additional machining of the female screw shape.

FIG. 20 is a perspective view showing a configuration in which the opening amount adjusting device 20 is detachable from the sound hole 2 by a shape to which a bayonet mount is applied.
In FIG. 20, the mounting member 26 is mounted on the cam member 21 instead of the mounting member 25 of the second embodiment. A plurality of claw portions 26a are provided on the rear surface side of the mounting member 26. Further, the sound hole 2 is provided with a notch portion 2b at a position corresponding to the claw portion 26a. Further, a protrusion that regulates the rotation of the claw portion 26a is attached to the inside of the front plate of the guitar 1. Due to the shape to which the bayonet mount is applied, the opening amount adjusting device 20 can be attached to and detached from the sound hole 2.

(Deformed form corresponding to curved surface mounting of the second embodiment)
In the above example, the description has been made on the assumption that the front plate of the guitar 1 is flat. However, with existing guitars, the front plate may be curved. An attachment form in such a case will be described.
FIG. 21 is a diagram illustrating a form in which the opening amount adjusting device 20 is attached when the front plate of the guitar is a curved surface.
In the example shown in FIG. 21, in the opening amount adjusting device 20 of the second embodiment, the spacer 27 is provided between the cam member 21 and the mounting member 25. One surface of the spacer 27 has a shape that follows the surface shape of the guitar 1, and the mounting member 25 is also deformed accordingly. Therefore, even a guitar 1 having a curved surface can be attached without play.

(Deformed form of movable member)
In the above-mentioned example, the movable member exemplifies a form in which the movable member operates like a diaphragm in a photographing lens. Not limited to this, the movable member may have any form as long as the opening amount of the sound hole can be changed. Hereinafter, the modified form will be illustrated.

FIG. 22 is a diagram showing a form in which the movable member 101 slides and moves. 22 (a) shows a closed state, and FIG. 22 (b) shows an open state.
FIG. 23 is a diagram showing a form in which the two movable members 102 and 103 slide and move. FIG. 23 (c) shows a closed state, and FIG. 23 (d) shows an open state.
FIG. 24 is a diagram showing a form in which the movable member 104 rotates. FIG. 24 (a) shows a closed state, and FIG. 24 (b) shows an open state.
As shown in FIGS. 22 to 24, the opening amount of the sound hole can be changed to an arbitrary amount even with a simple configuration. Further, in these forms, since the structure is simple, the opening amount adjusting device can be provided at a lower cost.

FIG. 25 is a diagram showing a form in which a plurality of louver-shaped movable members 105 rotate. FIG. 25 (a) shows a closed state, and FIG. 25 (b) shows an open state.
By using the louver-shaped movable member 105 as shown in FIG. 25, in addition to being able to adjust the opening amount of the sound hole, it is possible to control the sound spreading direction by the direction of the louver.

(Third Embodiment)
FIG. 26 is an exploded perspective view of the opening amount adjusting device 30 of the third embodiment as viewed diagonally from the front.
The opening amount adjusting device 30 of the third embodiment basically has the same configuration as that of the second embodiment. Therefore, the same reference numerals are given to the parts that perform the same functions as those of the second embodiment described above, and duplicate description will be omitted as appropriate.
The opening amount adjusting device 30 of the third embodiment includes a cam member 31, a movable member 32, a driving force transmission member 33, and a cover member 34.
The cam member 31, the movable member 32, and the cover member 34 have the same configurations as the cam member 21, the movable member 22, and the cover member 24 in the second embodiment, respectively.

The driving force transmission member 33 is formed in a substantially annular shape, and the movable member 32 is arranged so as to be sandwiched between the movable member 32 and the cam member 31. On the rear surface side of the driving force transmission member 33, there are 10 guide grooves (not shown) similar to the guide grooves 23a provided on the rear surface side of the operation member 23 of the second embodiment, which is the same number as the number of movable members 32. It is provided.
On the front surface side of the driving force transmitting member 33, three engaging convex portions 33a and three magnets 33b are provided. The number of the engaging protrusions 33a and the magnets 33b can be changed as appropriate.
The engaging convex portion 33a and the magnet 33b correspond to an engaging concave portion (not shown) provided on the rear surface side of the operating member 36 or the operating member 37, which will be described later, and a magnet (or a ferromagnet), respectively. It is placed in a position.

The opening amount adjusting device 30 of the third embodiment is further selectively attached with the operating member 36 or the operating member 37.
The operating member 36 is formed in a substantially annular shape. Two slightly protruding operation knobs 36a are provided on the front surface side of the operation member 36.
On the rear surface side of the operating member 36, an engaging concave portion (not shown) and a magnet (or a ferromagnet) are provided at positions corresponding to the engaging convex portion 33a of the driving force transmitting member 33 and the magnet 33b, respectively. Have been placed. The operation member 36 can be attached to the driving force transmission member 33 from the front side with the cover member 34 attached. With the above configuration, the operating member 36 can be detachably attached to the driving force transmitting member 33 by the magnetic force of the magnet 33b. Further, by engaging the engaging convex portion 33a with the engaging concave portion, the rotational driving force of the operating member 36 is transmitted to the driving force transmitting member 33, and the driving force transmitting member 33 can rotate, so that the movable member 32 can rotate. Can open and close.

Like the operating member 36, the operating member 37 is formed in a substantially annular shape. On the front surface side of the operating member 37, an operating lever portion 37a, which is not provided on the operating member 36 but extends long in the outer diameter direction and protrudes, is provided.
On the rear surface side of the operating member 37, an engaging concave portion (not shown) and a magnet (or a ferromagnet) are provided at positions corresponding to the engaging convex portion 33a of the driving force transmitting member 33 and the magnet 33b, respectively. Have been placed. The operation member 37 can be attached to the driving force transmission member 33 from the front side with the cover member 34 attached. With the above configuration, the operating member 37 can be detachably attached to the driving force transmitting member 33 by the magnetic force of the magnet 33b. Further, by engaging the engaging convex portion 33a with the engaging concave portion, the rotational driving force of the operating member 37 is transmitted to the driving force transmitting member 33, and the driving force transmitting member 33 can rotate, so that the movable member 32 can rotate. Can open and close.

Since both the operation member 36 and the operation member 37 can be easily attached and detached, both can be easily selected and used. The above-mentioned operation member 36 and the operation member 37 have different operation feelings, and can be replaced according to the user's preference. Further, although the above two examples are illustrated here, more operating members may be prepared. For example, it may be in a different color, or it may be an operating member with various decorations.

As described above, according to the third embodiment, since the plurality of operating members are easily and detachably configured, the operating members can be replaced according to the user's preference. Therefore, it is possible to newly manufacture and improve only the operation member for various purposes such as further improving the operability and further improving the design. In this case, the operating member may be not limited to the person (trader) who manufactured the opening amount adjusting device 30, but may be manufactured by another person (trader), and both the user and the industry concerned may be able to use it. For us, we can expect useful and developmental development.

(Deformed form)
Not limited to the embodiments described above, various modifications and changes are possible, and these are also within the scope of the present invention.

(1) In each embodiment, a configuration in which the movable member is made thick so that abnormal noise is not generated is illustrated. Not limited to this, for example, the movable member may be made thinner and the movable member may be intentionally vibrated so that different acoustic effects can be obtained. Further, by making the movable member thin, the movable members can overlap each other and retract, and the device can be made thinner.

(2) In each embodiment, an example in which an opening amount adjusting device is provided in a sound hole of a guitar has been described. Not limited to this, for example, the opening amount adjusting device of the present invention may be provided in the sound hole of a percussion instrument such as a cajon, or the opening amount adjusting device of the present invention may be provided in the sound hole (opening) of the speaker. ..

Although each embodiment and modified form can be used in combination as appropriate, detailed description thereof will be omitted. Further, the present invention is not limited to each of the embodiments described above.

1 Guitar 2 Sound hole 2b Notch 10 Opening amount adjusting device 11 Cam member 11a Cam groove 12 Movable member 12a Cam pin 12b Guide rib 13 Operating member 13a Guide groove 13b Operating knob 14 Cover member 14a Joint surface 20 Opening amount adjusting device 20a Shape 21 Cam member 21a Cam groove 22 Movable member 22a Cam pin 22b Guide rib 23 Operation member 23a Guide groove 23b Operation knob 24 Cover member 25 Mounting member 25a Engagement shape 26 Mounting member 26a Claw 27 Spacer 30 Opening amount adjusting device 31 Cam member 32 Movable member 33 Driving force transmission member 33a Engagement convex part 33b Magnet 34 Cover member 36 Operation member 36a Operation knob part 37 Operation member 37a Operation lever part 101, 102, 103, 104, 105 Movable member B screw M magnet

Claims (4)

An opening amount adjusting device provided in a sound hole that emits sound and including a movable member that can change the opening amount of the opening of the sound hole. In the opening amount adjusting device according to claim 1,
Provided with an operating member for operating the movable member,
An opening amount adjusting device characterized by. In the opening amount adjusting device according to claim 2,
The operating member is removable.
An opening amount adjusting device characterized by. In the opening amount adjusting device according to any one of claims 1 to 3.
The opening amount adjusting device can be retrofitted to an existing sound hole.
An opening amount adjusting device characterized by.

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