Patent Description:
The present invention relates to a body for a stringed instrument and a stringed instrument provided with the body.

A stringed instrument such as an electric guitar is provided with a body, a neck, and a head. In such a stringed instrument, vibration of a string is also transmitted to the body and the neck, with the body and neck also vibrating. The vibration energy of the string is consumed by the vibration of the body and the neck, whereby the vibration of the string is attenuated. For this reason, the vibration characteristics of the body and the neck influence the vibration of the string and the sound quality of the stringed instrument.

"<NPL>> discloses an electric guitar that includes a body that has been subjected to a cutaway process removing a portion of the body in order to make the electric guitar easy to play. In the body subjected to the cutaway process, the portions not cut away are formed as protrusions.

In this way, when protrusions are formed on the body in consideration of playability and the appearance design of the stringed instrument, the vibration characteristics of the body differ compared with the case where protrusions are not formed. Therefore, in a stringed instrument having a body in which protrusions are formed, there is room for improving the vibration characteristics of the body and for improving the sound quality.

<CIT> discloses a guitar body having a protrusion serving as a mounting portion for a strap and a rigidity reinforcing member attached to the back surface of the guitar body and not extending into said protrusion. In <CIT> an acoustic guitar is disclosed having brace members and a lower load displacement component designed to transfer the load from various connecting members to a soundboard area proximate to a faux bridge. <CIT> discloses a pickguard or scratch plate made of plywood. From <CIT> a body for a stringed instrument is known according to the preamble part of claim <NUM>.

The present invention was achieved in view of the above circumstances, and has as its object to provide a body for a stringed instrument that can improve sound quality even when protrusions are formed, and a stringed instrument provided with the same body.

A body for a stringed instrument according to the present invention is provided as defined in claim <NUM>. Advantageous embodiments can be configured according to any of claims <NUM>-<NUM>.

A body for a stringed instrument according to the present invention is provided with a body unit having a protrusion, and a rigidity adjusting member that is affixed to the body unit and that suppresses bending deformation of the protrusion in the body unit.

A stringed instrument according to the present invention is provided as defined in claim <NUM>.

A preferred embodiment of the present invention will be described in detail hereinbelow with reference to <FIG>. In the present embodiment, an electric guitar <NUM> is represented as an example of a stringed instrument according to the present invention.

As shown in <FIG>, the electric guitar <NUM> according to the present embodiment includes a body <NUM>, a neck <NUM>, and a string <NUM>.

The neck <NUM> is connected to an end portion of the body <NUM> and extends from the body <NUM> in the X-axis direction of <FIG>. A head <NUM> forming a distal end of the neck <NUM> in the lengthwise direction is provided with a tuning peg <NUM> onto which one end of a string <NUM> is wound. The string <NUM> is stretched along the lengthwise direction (string tensing direction, X-axis direction) of the neck <NUM>.

The body <NUM> of the electric guitar <NUM> includes a body unit <NUM> and a rigidity adjusting member <NUM>.

The body unit <NUM> is made of a solid body with no hollow portions inside. That is, the body unit <NUM> is formed in a plate shape. The body unit <NUM> is made of wood such as alder, maple, or mahogany. For example, the body unit <NUM> may also be constituted by combining two or more kinds of different wood materials.

In the following description, the lengthwise direction (string tensing direction, X-axis direction) of the neck <NUM>, which is a direction orthogonal to the thickness direction (Z-axis direction) of the body unit <NUM>, is referred to as the lengthwise direction of the body unit <NUM>. A direction (Y-axis direction) orthogonal to both the thickness direction and the lengthwise direction of the body unit <NUM> is referred to as the width direction of the body unit <NUM>.

The body unit <NUM> has a main body <NUM> and two protrusions <NUM> that are formed integrally.

The main body <NUM> is formed in a plate shape and constitutes a major portion of the body unit <NUM>. The main body <NUM> is connected to the neck <NUM> at a first end in the lengthwise direction. A connecting portion between the main body <NUM> and the neck <NUM> is located at an intermediate portion in the width direction of the main body <NUM>. In the present embodiment, the length of the main body <NUM> in the lengthwise direction is longer than the length of the main body <NUM> in the width direction.

A bridge <NUM>, an electromagnetic pickup <NUM>, and controllers are mounted on a surface of the main body <NUM>. The bridge <NUM>, the electromagnetic pickup <NUM>, and the controllers are mounted on a front surface 11a of the body unit <NUM> in the thickness direction (Z-axis direction).

The bridge <NUM> is located at a central portion in the width direction of the main body <NUM>. One end of the string <NUM> is held at the bridge <NUM>. The electromagnetic pickup <NUM> is positioned between the neck <NUM> and the bridge <NUM> in the lengthwise direction of the main body <NUM>. In the present embodiment, two electromagnetic pickups <NUM> are arranged side by side in the lengthwise direction of the main body <NUM>. The controllers adjust the volume, tone, and the like of a sound signal output from the electromagnetic pickup <NUM>. The controllers include two volume switches <NUM> and a pickup selector <NUM> for switching the electromagnetic pickup <NUM> to be operated.

The body unit <NUM> includes two protrusions <NUM> protruding from an edge of the main body <NUM>. Specifically, the protrusions <NUM> protrude in a direction orthogonal to the thickness direction of the main body <NUM> from an edge of the main body <NUM> (a portion indicated by an imaginary line L1 in <FIG>). The thickness of the protrusions <NUM> in the Z-axis direction is equal to the thickness of the main body <NUM>. Widths W3 and W4 of the protrusions <NUM> in the XY plane are formed in a shape that gradually decreases in the protrusion direction of each of the protrusions <NUM>.

In the body unit <NUM> of the present embodiment, the two protrusions <NUM> are formed spaced apart from each other. Although the number of the protrusions <NUM> in the present embodiment is two, the number is not limited thereto, and there may be one or three or more.

In the present embodiment, the two protrusions <NUM> are positioned at the first end portion of the main body <NUM> in the lengthwise direction. The two protrusions <NUM> are also positioned at both ends of the main body <NUM> in the width direction. That is, the two protrusions <NUM> are arranged with a space therebetween, sandwiching the neck <NUM> in the width direction of the main body <NUM>.

When vibration is applied to the body unit <NUM> constituted as described above, a predetermined vibration mode is excited in the body unit <NUM> at a predetermined natural frequency.

<FIG> shows vibration in the body unit <NUM> that is excited in a "torsional mode" in which the body unit <NUM> vibrates so as to be twisted about an axis A1 of the body unit <NUM> extending in the lengthwise direction of the body unit <NUM>. In the grayscale of <FIG>, a whiter portion indicates a greater vibration displacement, while a blacker portion indicates a smaller vibration displacement.

A portion of the body unit <NUM> where the vibration displacement is large corresponds to an antinode of a standing wave in a "torsional mode" (hereinafter referred to as a torsional mode antinode). In the present embodiment, as shown in <FIG>, four portions located at both ends in the lengthwise direction of the body unit <NUM> and at both ends in the width direction of the body unit <NUM> correspond to torsional mode antinodes. In this embodiment, of those four portions, vibration displacement at the two portions where the protrusions <NUM> are formed is greater than the vibration displacement at the other two portions.

On the other hand, a portion of the body unit <NUM> where there is no displacement or where the vibration displacement is small, which is indicated by the color black in the drawing, corresponds to a node of a standing wave in the "torsional mode" (hereinafter referred to as a torsional mode node). In the present embodiment, as shown in <FIG>, a central portion <NUM> of the body unit <NUM> located mainly in the middle of the body unit <NUM> in the lengthwise direction and in the middle of the body unit <NUM> in the width direction corresponds to the torsional mode node.

<FIG> shows vibration in the body unit <NUM> that is excited in a "bending mode" in which the body unit <NUM> vibrates so as to curve in the width direction around an axis A1 of the body unit <NUM>. In the grayscale of <FIG>, a whiter portion indicates a greater vibration displacement, while a blacker portion indicates a smaller vibration displacement.

A portion of the body unit <NUM> where the vibration displacement is large, which is indicated by the color white, corresponds to an antinode of a standing wave in a "bending mode" (hereinafter referred to as a bending mode antinode). In the present embodiment, as shown in <FIG>, bending mode antinodes are positioned at both ends of the body unit <NUM> in the width direction, particularly both ends of the body unit <NUM> in the width direction located on a second end portion side of the body unit <NUM> in the lengthwise direction. The second end portion of the body unit <NUM> is an end portion located on the side opposite to the first end portion of the body unit <NUM> in the lengthwise direction of the body unit <NUM>.

On the other hand, a portion of the body unit <NUM> where there is no displacement or where the vibration displacement is small, which is indicated by the color black, corresponds to a node of a standing wave in the "bending mode" (hereinafter referred to as a bending mode node). In the present embodiment, as shown in <FIG>, the bending mode node is positioned in the middle of the body unit <NUM> in the width direction.

Referring again to <FIG>, the rigidity adjusting member <NUM> is affixed to the body unit <NUM> so as to adjust the rigidity of the body unit <NUM> in order to change the aforementioned vibration characteristics of the body unit <NUM>, in particular the frequency characteristic of vibration. That is, the rigidity adjusting member <NUM> is affixed to the body unit <NUM> so as to suppress bending deformation of the protrusions <NUM> of the body unit <NUM>. Specifically, the rigidity adjusting member <NUM> extends from the central portion <NUM> of the body unit <NUM> to each of the protrusions <NUM>. The central portion <NUM> of the body unit <NUM> is located in the main body <NUM> of the body unit <NUM>. In <FIG>, the rigidity adjusting members <NUM> are indicated by dotted hatching.

In the present embodiment, the above-described torsional mode node is located at the central portion <NUM> of the body unit <NUM>. A distal ends of the rigidity adjusting member <NUM> in the extension direction thereof should at least reach the protrusion <NUM>. The distal ends of the rigidity adjusting member <NUM> need not for example reach the distal end of the protrusion <NUM> in the projecting direction thereof. In the present embodiment, the distal end of the rigidity adjusting member <NUM> reaches the distal end of the protrusion <NUM> in the projecting direction thereof.

As shown in <FIG> and <FIG>, the rigidity adjusting member <NUM> has a contact surface <NUM> for making contact with the body unit <NUM>. The entire contact surface <NUM> of the rigidity adjusting member <NUM> contacts and is affixed to the body unit <NUM>.

The fixing surface of the body unit <NUM> in the present embodiment is the front surface 11a of the body unit <NUM>. The rigidity adjusting member <NUM> should be affixed to the front surface 11a of the body unit <NUM> by bonding or the like, rather than by screw fastening at a plurality of places. That is, the rigidity adjusting member <NUM> should be affixed to the body unit <NUM> over a surface rather than being fixed at points.

In the present embodiment, the rigidity adjusting member <NUM> is formed in a band shape extending from the central portion <NUM> of the body unit <NUM> to the protrusion <NUM>. The contact surface <NUM> of the rigidity adjusting member <NUM> is a surface facing in the plate thickness direction of the rigidity adjusting member <NUM>.

The specific rigidity of the rigidity adjusting member <NUM> is higher than that of the body unit <NUM>. The rigidity adjusting member <NUM> of the present embodiment is made of a fiber-reinforced member containing fibers harder than the body unit <NUM>. A direction of the fibers (lengthwise direction of the fibers) is oriented in the extension direction of the rigidity adjusting member <NUM> in the X-Y plane (that is, in the direction from the central portion <NUM> of the body unit <NUM> to the protrusion <NUM> in <FIG>). While the direction of the fibers may completely agree with the extension direction of the rigidity adjusting member <NUM>, the direction may also may be somewhat inclined with respect to the extension direction, for example. That is, provided the fiber direction is at least not perpendicular to the extension direction of the rigidity adjusting member <NUM>, the direction is not particularly limited. The fiber-reinforced member constituting the rigidity adjusting member <NUM> may be made of carbon fiber reinforced plastic (CFRP) or the like containing carbon fibers, for example. Constituting the rigidity adjusting member <NUM> with a fiber-reinforced member enables a reduction in weight of the rigidity adjusting member <NUM>.

In the X-Y plane, widths W1 and W2 of the respective rigidity adjusting members <NUM>, which are orthogonal to the extension direction of the rigidity adjusting members <NUM>, may be equal to or greater than half of the widths W3 and W4 of the protrusions <NUM> and equal to or less than the widths W3 and W4.

The body <NUM> of the present embodiment is provided with two rigidity adjusting members <NUM>. The two rigidity adjusting members <NUM> respectively extend to the two protrusions <NUM>. That is, the number of the rigidity adjusting members <NUM> is the same as the number of the protrusions <NUM>.

The two rigidity adjusting members <NUM> may for example be formed separately. In the present embodiment, the two rigidity adjusting members <NUM> are integrally formed. The two rigidity adjusting members <NUM> are joined to each other by a connecting portion <NUM> at the center portion <NUM> of the body unit <NUM> (the torsional mode node).

As described above, the two protrusions <NUM> in the body unit <NUM> of the present embodiment are positioned at the first end of the main body <NUM> in the lengthwise direction. Therefore, each of the rigidity adjusting members <NUM> extends from the central portion <NUM> of the main body <NUM> (the torsional mode node) toward the first end side of the main body <NUM>.

Further, at the first end of the main body <NUM>, the two protrusions <NUM> are positioned at both ends in the width direction of the main body <NUM>. Therefore, heading in the lengthwise direction of the main body <NUM> from the central portion <NUM> of the main body <NUM> toward the first end, the rigidity adjusting members <NUM> each extend in a sloping manner so as to approach both ends in the width direction of the main body <NUM>. As a result, the rigidity adjusting members <NUM> form a V shape as a whole.

In addition, the rigidity adjusting members <NUM> are formed so as not to extend from the central portion <NUM> of the main body <NUM> (the torsional mode node) toward the bending mode antinodes of the main body <NUM>. Specifically, the rigidity adjusting members <NUM> are not provided at portions of the main body <NUM> at both ends in the width direction adjacent to the central portion <NUM> of the main body <NUM>, and at portions adjacent to those ends on the second end side in the lengthwise direction.

As illustrated in <FIG>, the connecting portion <NUM> of the two rigidity adjusting members <NUM> extends toward the second end side in the lengthwise direction of the main body <NUM> and reaches the second end. In this case, the width of the connecting portion <NUM> in the Y-axis direction is preferably small enough not to protrude from the bending mode node of the main body <NUM> (the center portion in the width direction of the main body <NUM>). As shown in <FIG>, the connecting portion <NUM> may also be positioned apart from the second end of the main body <NUM> so as not to reach the second end of the main body <NUM>. The connecting portion <NUM> may also be located only in the central portion <NUM>.

The body <NUM> of the electric guitar <NUM> of the present embodiment configured as described above has the vibration frequency characteristic shown by the solid line F1 in <FIG>. The broken line F2 in <FIG> shows the vibration frequency characteristic in the body of a comparative example that does not have the rigidity adjusting member <NUM>.

In a body of the comparative example, vibration in the torsional mode occurs at natural frequency f <NUM>, and vibration in the bending mode occurs at natural frequencies f21 and f23. On the other hand, in the body <NUM> of the embodiment, vibration in the torsional mode occurs at natural frequency f12, and vibration in the bending mode occurs at natural frequencies f22 and f24.

As shown in <FIG>, the natural frequency f12 corresponding to the torsional mode in the body <NUM> of the embodiment is higher than the natural frequency f11 corresponding to the torsional mode in the body of the comparative example. That is, attaching the rigidity adjusting member <NUM> to the body unit <NUM> has the effect of raising the natural frequency corresponding to the torsional mode.

In addition, two natural frequencies f22, f24 corresponding to the bending mode in the body <NUM> of the embodiment are higher than two respective natural frequencies f21, f23 corresponding to the bending mode in the body of the comparative example. That is, attaching the rigidity adjusting members <NUM> to the body unit <NUM> has the effect of raising the natural frequencies corresponding to the bending mode.

However, the respective differentials between the two natural frequencies f22, f24 corresponding to the bending mode in the embodiment and the two natural frequencies f21, f23 corresponding to the bending mode in the comparative example are smaller than the differential between the natural frequency f12 corresponding to the torsional mode in the embodiment and the natural frequency f11 corresponding to the torsional mode in the comparative example. This is because the rigidity adjusting member <NUM> of the present embodiment extends from the torsional mode node of the body unit <NUM> toward the torsional mode antinodes (protrusions <NUM>), but does not extend from the bending mode node toward the bending mode antinodes.

As described above, the rigidity adjusting member <NUM> can change the vibration characteristic (vibration frequency characteristic) of the body <NUM> of the embodiment with respect to the vibration characteristic of the body of the comparative example. Therefore, the rigidity adjusting member <NUM> can improve the sound quality of the electric guitar <NUM> having the body <NUM> of the embodiment compared to the sound quality of an electric guitar having the body of the comparative example.

As described above, the body <NUM> of the electric guitar <NUM> of the present embodiment is provided with the rigidity adjusting member <NUM> extending from the torsional mode node (the central portion <NUM>) located in the main body <NUM> to the protrusion <NUM>. In addition, the entire contact surface <NUM> of the rigidity adjusting member <NUM> is affixed to the fixing surface (surface 11a) of the body unit <NUM>. Therefore, bending deformation of the protrusion <NUM> with respect to the main body <NUM> is suppressed, and so the rigidity of the body <NUM> can be partially increased. As a result, as shown in <FIG>, the natural frequency of the body <NUM> vibrating in a predetermined vibration mode (torsional mode, bending mode) can be increased. Accordingly, the vibration characteristic of the body <NUM> can be improved by the rigidity adjusting member <NUM>, and the sound quality of the electric guitar <NUM> can be improved.

In the body <NUM> of the electric guitar <NUM> of the present embodiment, the rigidity adjusting member <NUM> is made of a fiber-reinforced member containing fibers harder than the body unit <NUM>. Moreover, the fiber direction is oriented in the extension direction of the rigidity adjusting member <NUM>. Therefore, it is possible to effectively suppress bending deformation of the protrusion <NUM> with respect to the main body <NUM> while reducing the weight of the rigidity adjusting member <NUM>. Thereby, the natural frequency of the body <NUM> corresponding to a predetermined vibration mode (torsional mode, bending mode) can be further increased.

Further, in the body <NUM> of the electric guitar <NUM> of the present embodiment, by changing the rigidity of the rigidity adjusting member <NUM> and the hardness of the fibers of the fiber-reinforced member constituting the rigidity adjusting member <NUM>, it is possible to adjust the degree of suppressing bending deformation of the protrusion <NUM> with respect to the main body <NUM> (the rigidity of the body <NUM> and the degree of increase in the natural frequency of the body <NUM>).

Further, in the body <NUM> of the electric guitar <NUM> of the present embodiment, a plurality of the rigidity adjusting members <NUM> respectively extend to a plurality of the protrusions <NUM>. Therefore, even if the body <NUM> has a plurality of the protrusions <NUM>, it is possible to suppress bending deformation of the protrusions <NUM> with respect to the main body <NUM> by the plurality of rigidity adjusting members <NUM>.

In addition, in the body <NUM> of the electric guitar <NUM> of the present embodiment, the rigidity of the body <NUM> with respect to the torsional mode can be enhanced by integrally forming the plurality of rigidity adjusting members <NUM>. This makes it possible to actively increase the natural frequency of the body <NUM> corresponding to the torsional mode.

In the body <NUM> of the electric guitar <NUM> of the present embodiment, the rigidity adjusting member <NUM> extends from the torsional mode node toward the first end side of the main body <NUM> to which the neck <NUM> is connected. Therefore, it is possible to prevent the rigidity adjusting member <NUM> from being formed so as to spread out from the torsional mode node in the width direction of the main body <NUM>. This makes it possible to suppress an increase in the natural frequency of the body <NUM> corresponding to the bending mode to a small value while actively increasing the natural frequency of the body <NUM> corresponding to the torsional mode.

More specifically on this point, displacement of vibration of the body <NUM> in the bending mode is large at portions on both sides of the torsional mode node in the width direction of the main body <NUM>. In contrast, in the present embodiment, the rigidity adjusting member <NUM> is formed so as not to reach portions on both sides of the torsional mode node. Therefore, it is possible to prevent the rigidity adjusting members <NUM> from excessively inhibiting vibration in the bending mode. Thereby it is possible to suppress an increase in the natural frequency of the body <NUM> corresponding to the bending mode to a small value.

Further, in the body <NUM> of the electric guitar <NUM> of the present embodiment, the respective widths W1 and W2 of the rigidity adjusting members <NUM> are equal to or greater than half of the widths W3 and W4 of the protrusions <NUM> and equal to or less than the widths W3 and W4. Therefore, compared with the case of the widths W1 and W2 of the rigidity adjusting members <NUM> being smaller than half of the widths W3 and W4 of the protrusions <NUM>, bending deformation of the protrusions <NUM> with respect to the main body <NUM> can be effectively suppressed.

With these effects, it is possible to improve the sound quality of the electric guitar <NUM> provided with the body <NUM>.

While preferred embodiments of the invention have been described and illustrated above, it should be understood that these are exemplary of the invention and are not to be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the scope of the present invention. Accordingly, the invention is not to be considered as being limited by the foregoing description, and is only limited by the scope of the appended claims.

In the present invention, when the body unit has a plurality of protrusions, the number of the rigidity adjusting members may for example be smaller than the number of the protrusions. That is, the rigidity adjusting member may extend from the torsional mode node in the body portion to for example one or some of the plurality of protrusions. For example, when there are three protrusions, two rigidity adjusting members may respectively extend to two of the protrusions, or one rigidity adjusting member may extend to one protrusion.

The body of a stringed instrument of the present invention is applicable not only to an electric guitar of the above embodiment but also to any stringed instrument having a body.

Claim 1:
A body (<NUM>) for a stringed instrument (<NUM>) that includes a neck (<NUM>) connected to the body and a bridge (<NUM>) that supports a plurality of strings (<NUM>) extending between a distal end of the neck and the body, the body comprising:
a solid body (<NUM>) with a front surface (11a) and a back surface (11b), and a distal end on a side where the neck (<NUM>) extends from the solid body, the solid body being shaped to provide a first protrusion (<NUM>) that extends outwardly on the side of the distal end; and
a first rigidity adjusting member (<NUM>) that extends from a central portion of the solid body (<NUM>),
wherein the first rigidity adjusting member (<NUM>) is affixed to the front surface (11a) of the solid body (<NUM>), where the bridge is disposed, and extends to the first protrusion in an extension direction of the first rigidity adjusting member (<NUM>), the first rigidity adjusting member (<NUM>) being made of a fiber-reinforced member,
characterized in that the fiber-reinforced member includes fibers harder than the solid body, with the direction of the fibers being oriented in the extension direction of the first rigidity adjusting member (<NUM>).