Keyboard and keyboard component

A keyboard includes a frame and a plurality of mass bodies. The mass bodies are arranged in parallel to each other. Each of the mass bodies is pivotally supported to pivot about a pivot fulcrum with respect to the frame. The mass bodies are at least one of a plurality of keys configured to be directly operated, a plurality of interlocking members configured to pivot in conjunction with a corresponding one of the plurality of keys, embedded members in the plurality of keys or embedded members in the plurality of interlocking members. At least some of the mass bodies include notched portions being arranged in order from a pitch, which is equal to or greater than a lowest pitch, to a highest pitch. The notched portions are different from each other in at least one of size, position, or distance from the pivot fulcrum.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No. 2019-126802, filed on Jul. 8, 2019. The entire disclosure of Japanese Patent Application No. 2019-126802 is hereby incorporated herein by reference.

BACKGROUND

Technical Field

The present invention relates to a keyboard and a keyboard component having a plurality of mass bodies arranged parallel to each other.

Background Information

A keyboard in which a plurality of mass bodies that pivot in conjunction with corresponding keys are arranged parallel to each other in order to impart inertia to an operation of keys on the keyboard is known from the prior art. A keyboard of this type is known in which a weight is attached to each of the main bodies of a plurality of mass bodies, each weight having a hollow portion and the same outer edge shape (Japanese Patent No. 3680687). In this device, the volume of the hollow portion of the weight to be attached is individually set to thereby vary the moment of inertia of each mass body and to achieve key scaling with a tactile sense of the keying operation. That is, in the keyboard of Japanese Patent No. 3680687, a plurality of types of weight thicknesses and a plurality of types of hole sizes formed in the weights are provided, to thereby realize weights of varying mass by means of combinations of thicknesses and hole sizes.

SUMMARY

However, in the keyboard of Japanese Patent No. 3680687, it is necessary to manufacture each weight by managing the combination of thickness and hole size. Specifically, increasing the number of keys that are included in the keyboard necessitates greater manufacturing precision to set the moment of inertia of each mass body to the desired accuracy across the entire sound range. Manufacturing the mass bodies one at a time, on the other hand, would ensure precision but at reduced production efficiency. Thus, there is the problem that efficiently manufacturing various types of mass bodies having different inertia is not a simple matter.

One object of this disclosure is to provide a keyboard that can facilitate the manufacture of a plurality of mass bodies having different moments of inertia.

In one aspect of this disclosure, a keyboard comprises a frame and a plurality of mass bodies. The plurality of mass bodies are arranged in parallel to each other, and each of the plurality of mass bodies is pivotally supported to pivot about a pivot fulcrum with respect to the frame. The plurality of mass bodies are at least one of a plurality of keys configured to be directly operated, a plurality of interlocking members configured to pivot in conjunction with a corresponding one of the plurality of keys, embedded members in the plurality of keys or embedded members in the plurality of interlocking members. At least some of the plurality of mass bodies include notched portions being arranged in order from a pitch, which is equal to or greater than a lowest pitch, to a highest pitch. The notched portions are different from each other in at least one of size, position, or distance from the pivot fulcrum.

In another aspect of this disclosure, a keyboard comprises a frame and a plurality of mass bodies. The plurality of mass bodies are arranged in parallel to each other, and each of the plurality of mass bodies is pivotally supported to pivot about a pivot fulcrum with respect to the frame. The plurality of mass bodies are at least one of a plurality of keys configured to be directly operated or a plurality of interlocking members configured to pivot in conjunction with a corresponding one of the plurality of keys. The plurality of mass bodies are divided into different areas classified according to key type or sound range, each of the plurality of mass bodies has a unique portion and a common portion, the unique portions have shapes that are different from each other between the different areas but identical within a same one of the different areas, and the common portions have shapes that are identical to each other in the different areas except for if a notched portion is provided in the common portions. At least some of the plurality of mass bodies have notched portions within the same one of the different areas being arranged in order from a pitch, which is equal to or greater than a lowest pitch of the same one of the different areas, to a highest pitch of the same one of the different areas. The notched portions of the plurality of mass bodies within the same one of the different areas are configured such that the notched portions are aligned to form a continuous path that is not parallel to an arrangement direction in a state in which the plurality of mass bodies within the same one of the different areas are removed from the frame and arranged parallel to each other side by side in the arrangement direction with either positions of the common portions being aligned or the pivot fulcrum being concentric among the plurality of mass bodies within the same one of the different areas.

In another aspect of this disclosure, a keyboard component comprises a plurality of mass bodies, which are at least one of a plurality of keys configured to be directly operated, a plurality of interlocking members configured to pivot in conjunction with a corresponding one of the plurality of keys, embedded members in the plurality of keys or embedded members in the plurality interlocking members. The plurality of mass bodies are divided into different areas classified according to key type or sound range, each of the plurality of mass bodies has a unique portion and a common portion, the unique portions have shapes that are different from each other between the different areas but identical within a same one of the different areas, and the common portions have shapes that are identical to each other in the different areas except for if a notched portion is provided in the common portions. At least some of the plurality of mass bodies have notched portions within the same one of the different areas being arranged in order from a pitch, which is equal to or greater than a lowest pitch of the same one of the different areas, to a highest pitch of the same one of the different areas. The notched portions of the plurality of mass bodies within the same one of the different areas are configured such that a side surface defining a contour of a notch shape for each of the notched portions is not parallel to an arrangement direction in a state in which the plurality of mass bodies within the same one of the different areas are arranged parallel to each other side by side in the arrangement direction with either positions of the common portions being aligned or the pivot fulcrum being concentric among the plurality of mass bodies within the same one of the different areas.

According to one aspect of this disclosure, it is possible to facilitate the manufacture of a plurality of mass bodies having different moments of inertia.

DETAILED DESCRIPTION OF EMBODIMENTS

First Embodiment

FIG. 1is schematic cross-sectional view of a keyboard1according to a first embodiment. The keyboard1is applied to an electronic keyboard instrument, for example.FIG. 1illustrates an undepressed state (state in which a key K and a mass body HM, described further below, are in a pivot start position). Hereinbelow, a rocking-end side of a key in the aforementioned keyboard1(free end side) (left side inFIG. 1) is referred to as the front, and the key fulcrum-side (right side in the figure) in the keyboard1is referred to as the rear.

The device includes a plurality of keys K (white keys and black keys) that can be depressed, and a plurality of mass bodies HM (keyboard component) corresponding to each of the keys K. Since the configuration corresponding to each of the keys K is basically the same, for the purpose of explanation, unless specifically required, no distinction is made between the white keys and the black keys. A frame10is provided on a shelf, which is not shown. A key support point11is provided at the rear portion of the frame10in correspondence with each key K. Each key K is supported so as to pivot about the corresponding key fulcrum11.

A hammer pivot fulcrum15is provided on the frame10in correspondence with each mass body HM. Each mass body HM is a hammer that is supported so as to pivot about the corresponding hammer pivot fulcrum15. Each key K and the corresponding mass body HM are connected to each other so as to pivot by means of a connecting pin17. When the operating key K pivots, the corresponding mass body HM pivots in conjunction with the aforementioned key. An upper stopper13is provided at the rear portion of the frame10, and a lower stopper14is provided on the shelf. In the undepressed state, the mass body HM strikes the lower stopper14due to its own weight, thereby regulating the pivoting start position of the mass body HM. In addition, in the depressed state, the mass body HM strikes the upper stopper13, thereby regulating the pivoting end position of the mass body HM. When the operation of depressing the key K is released, the mass body HM and the key K return to the pivoting start position in conjunction therewith due to the dead weight of the mass body HM.

In the pivoting stroke from the pivoting start position to the pivoting end position of the mass body HM, the mass body HM presses a switch12provided on the frame10, and the depression operation is thereby detected. Based on this detection result, an unillustrated control unit generates a sound using an unillustrated sound source.

The basic configuration of the mass body HM is common to all the mass bodies HM, and the mass body HM is composed of a first member21and a second member22. As described further below, the shape of the second member22can differ for some or all of the mass bodies HM. The second member22is formed of metal, or the like, in order to function as a weight. The second member22is an integrated member having a unique portion24and a common portion25. A notched portion23(described further below) is formed in the common portion25. On the other hand, the first member21is made of resin, which is a material different from metal. When the mass body HM is molded with a mold, the second member22is insert-molded inside the first member21made of resin by means of simultaneous molding of a resin outsert with respect to the second member22as a metal weight, to thereby produce the mass body HM.

FIG. 2is a schematic plan view of a plurality of mass bodies HM arranged parallel to each other in the aforementioned keyboard1. The area (group) to which a plurality of the mass bodies HM arranged in the aforementioned keyboard1belong is divided into a plurality of areas according to key type or sound range. The mass bodies HM in all the groups are arranged such that the hammer pivot fulcrums15become concentric, and the rear end positions of the second members22are also substantially coincident with respect to each of the mass bodies HM. As an example,FIG. 2shows twelve mass bodies HM belonging to one area of the plurality of areas classified by one-octave unit. The number and method of division of the areas are not limited. Each of the areas can be classified by a plurality of octaves, or sound range, irrespective of octaves. Alternatively, the division need not be with respect to pitch, and the mass bodies HM can be divided into areas corresponding to a plurality of white keys and areas corresponding to a plurality of black keys.

FIG. 3is a view illustrating differences in shape of the second members22for each area. In the example ofFIG. 3, three groups are shown: group A, group B, and group C. These groups are classified according to sound range, and the sound ranges are in the order of group A<group B<group C, where group C is the highest sound range. The number of groups can also be four or more. For example,FIG. 2illustrates the group of the mass bodies HM of the group A. In all the groups, the shapes of the common portions25of the mass bodies HM are the same if no notched portions23are provided. The first member21is common to all mass bodies HM. The shape of the unique portion24of the mass bodies HM belonging to the same group is the same. The shapes of the unique portions24differ for mass bodies HM that belong to different groups.

For example, the length of the unique portion24is shorter for the unique portions24of the group B than for the unique portions24of the Group A, and even shorter for the unique portions24of the group C. As a result, the moment of inertia of the mass body HM is lower in groups closer to the treble notes. Due to the differences in the shapes of the unique portions24, providing gross differences in the moments of inertia for each group is easily achieved. The differences in the shapes of the unique portions24is not limited to differences in length, as long as the differences in shape contribute to differences in the moment of inertia.

On the other hand, the setting of minute differences in the moments of inertia within the same group is achieved by the notched portions23. Regarding the notched portions23, the shape of the notched portions23of the mass bodies HM belonging to the same area is the same, and the positions of the notches (positions of formation) are different from each other. As shown inFIG. 2, all of the notched portions23are inclined in plan view. That is, side surfaces23a,23bof each notched portion23are inclined such that the treble sides thereof are closer to the rear end side. Since the depth of each notched portion23is the same, a bottom surface23cof each notched portion23is essentially parallel to the axial direction of the hammer pivot fulcrum15. In this embodiment, each of the notched portions23is unfilled and free of any materials.

The position of the center of gravity G of each notched portion23in the longitudinal direction (front-rear direction) of the mass body HM will now be considered. First, distances D1from the hammer pivot fulcrum15to the center of gravity G differ for the mass bodies HM belonging to the same area. In addition, distances D2from the rear end position of the second member22to the center of gravity G differ for the mass bodies HM belonging to the same area. That is, the distance D1increases as the corresponding pitch increases among the mass bodies HM belonging to the same area, and the distance D2decreases as the corresponding pitch increases. That is, the notched portion23shifts to the rear end side as the corresponding pitch increases. As a result, although the shape of the second member22excluding the notched portion23is the same within the same group, the moment of inertia is lower in the mass body HM whose corresponding pitch is higher.

Next, the method for manufacturing the keyboard component including the plurality of mass bodies that have notched portions will be described. The method includes forming the notched portions of the plurality of mass bodies such that the notched portions are different from each other in at least one of size or position, or both, and cutting the workpiece.

In one example, the method further includes fixing the workpiece to a fixing jig. The forming of the notched portions is performed by forming a groove on the workpiece after the fixing of the workpiece to the fixing jig, and the forming of the groove is performed by moving a cutter relative to the workpiece. After the forming of the groove, the cutting of the workpiece is performed such that the workpiece is cut into the plurality of mass bodies. More specifically, using Group A as an example, the method for manufacturing the second members22of the mass bodies HM will be described with reference toFIGS. 4 and 5.FIG. 4is a plan view of a workpiece220after the notched portion23has been formed.FIG. 5is a rear view of the workpiece220during the formation of the notched portion23.

The workpiece220is a block-shaped metal member having the same thickness as the total thickness of the second members22for one group. Before the workpiece220is cut into individual second members22, an operator forms continuous groove230in the workpiece220which becomes the notched portions23. First, as shown inFIG. 5, the operator clamps the workpiece220between fixing jigs102,103on a worktable101. The operator then moves a rotary cutter18relative to the workpiece220to thereby form the continuous groove230in a straight line in the workpiece220. At this time, as shown inFIG. 4, the operator sets the direction of movement of the cutter18such that, in a plan view, the rear end surface of the workpiece220and the direction of formation of the continuous groove230form an angle θ, and such that the treble side of the continuous groove230is inclined toward the rear end side. The rear end surface of the workpiece220is essentially parallel to the axial direction of the hammer pivot fulcrum15and the arrangement direction of the second members22, when the mass bodies HM are arranged in the aforementioned keyboard1.

After forming the continuous groove230, the operator cuts out a plurality of the second members22by cutting the workpiece220for each designed thickness of the second member22. The second members22are completed after deburring, and the like. The formation of the notched portions23of the second members22can essentially be formed all at once by forming one continuous groove230, which is efficient. Thereafter, as described above, the operator forms the mass body HM by insert-molding the second members22in the first member21

As described above, the notched portions23of the plurality of mass bodies HM within the same one of the different areas are configured such that a side surface (23a,23b) defining a contour of a notch shape for each of the notched portions23is not parallel to an arrangement direction in a state in which the plurality of mass bodies HM within the same one of the different areas are arranged parallel to each other side by side in the arrangement direction with either positions of the common portions25being aligned or the pivot fulcrum15being concentric among the plurality of mass bodies HM within the same one of the different areas. More specifically, in a state in which the mass bodies HM are arranged in the aforementioned keyboard1(FIG. 2), the side surfaces23a,23bfrom among the constituent surfaces of each notched portion23(side surfaces governing the outline of the notch shape) are not parallel to the arrangement direction of the second members22or the axial direction of the hammer pivot fulcrum15. In addition, of the constituent surfaces of each notched portion23, the bottom surface23cis essentially parallel to the arrangement direction of the second members22and the axial direction of the hammer pivot fulcrum15.

In addition, in a state in which the mass bodies HM are arranged in the aforementioned keyboard1, the side surfaces23aand the side surfaces23bof the notched portions23are substantially parallel but not flush with each other. This is because, although the second members22are arranged essentially without intervals in the step preceding their being cut out from the workpiece220, a prescribed interval is provided between adjacent second members22during their arrangement in the aforementioned keyboard1.

From this standpoint, the above can be expressed as follows. The notched portions23of the plurality of mass bodies HM within the same one of the different areas are configured such that the notched portions23are aligned to form a continuous path that is not parallel to the arrangement direction in a state in which the plurality of mass bodies HM within the same one of the different areas are removed from the frame10and arranged parallel to each other side by side in the arrangement direction with either positions of the common portions25being aligned or the pivot fulcrum15being concentric among the plurality of mass bodies HM within the same one of the different areas. More specifically, it is assumed that a group of mass bodies HM belonging to the same area (group) are removed from the frame10and that the group of mass bodies HM are arranged parallel to each other such that the hammer pivot fulcrums15thereof are concentric (or such that the rear end positions of the common portions25are coincident). Here, there is a prescribed arrangement mode in which the constituent surfaces (side surfaces23a,23b, bottom surface23c) of each of the notched portions23are substantially flush. That the constituent surfaces are “substantially flush” means that the constituent surfaces are included in a common virtual plane and that the surfaces are completely flush. The prescribed arrangement mode in the examples ofFIGS. 4 and 5is an arrangement mode in which the second members22are arranged parallel to each other without intervals therebetween. That is, the prescribed arrangement mode is an arrangement mode in which a set of the notched portions23and the continuous groove230are located. In this arrangement mode, some (side surfaces23a,23b) of the constituent surfaces of the notched portion23are not parallel to the arrangement direction of the mass bodies HM (axial direction of the hammer pivot fulcrum15).

According to the present embodiment, of the plurality of mass bodies HM, the notched portion23is formed in each of the mass bodies HM in a range from a pitch greater than or equal to the lowest pitch to the highest pitch, and the positions of the notches of the notched portions23differ from each other. First, the mass bodies HM belonging to different areas (groups) have unique portions24that have different shapes, as well as common portions25which have the same shape if there are no notched portions23. Differences in the moment of inertia between the mass bodies HM belonging to different areas can be generated as a result of differences in the shapes of the unique portions24. The positions (D2) of the notches of the notched portions23for the group of mass bodies HM belonging to the same area differ from each other (the distances D1from the hammer pivot fulcrum15are different). That is, differences in the moments of inertia between the mass bodies HM belonging to the same area can be generated as a result of differences in the notch positions (D2) of the notched portions23. Thus, it is possible to easily provide various types of mass bodies HM that have different moments of inertia. Moreover, since the notched portions23of the second members22can be formed all at once at the stage of the workpiece220, the manufacturing efficiency is high. Thus, it is possible to facilitate the manufacture of a plurality of the mass bodies HM that have different moments of inertia. It becomes a simple matter to gradually change the moments of inertia of all the mass bodies HM of the keyboard1continuously in accordance with the corresponding pitch, and key scaling with a tactile sense of the keying operation is achieved at low cost.

In one example discussed above, after the continuous groove230on the workpiece220is formed, the workpiece220is separated into individual second members22by cutting the workpiece220, but the method for manufacturing the second members22is not limited thereby. In a modified example, the method further includes fixing the plurality of mass bodies to a fixing jig after the cutting of the workpiece. More specifically, the workpiece is cut into the plurality of mass bodies, and then the plurality of mass bodies are fixed to the fixing jig. The forming of the notched portions is performed by forming a groove on the plurality of mass bodies that are arranged parallel to each other and fixed to the fixing jig. The forming of the groove is performed by moving a cutter relative to the plurality of mass bodies.FIG. 6is a plan view of a plurality of the second members22for explaining the method for manufacturing the second members22according to the modified example. The operator produces one group's worth of the second members22in advance by cutting, or the like. Thereafter, in a state in which the rear end positions of the second members22are matched and all of the second members22are arranged parallel to each other with spacers26interposed between adjacent second members22, the operator clamps the second members22in the width direction with the fixing jigs102,103. Then, the operator moves the rotary cutter18relative to all of the second members22to thereby form the linear continuous groove230all at once.

If the one group's worth of second members22produced in this manner are arranged parallel to each other, maintaining intervals equal to the thickness of the spacer26between adjacent second members22, the constituent surfaces of the notched portions23become substantially flush with each other. This arrangement mode corresponds to the prescribed arrangement mode described above.

It is also possible to form the continuous groove230in a state in which adjacent second members22are brought into contact with each other without using the spacers26. In this case, if the adjacent second members22on which the notched portions23are formed are brought into contact with each other and arranged parallel to each other, the constituent surfaces of the notched portions23become substantially flush with each other. Thus, considering the manufacturing methods shown inFIGS. 4 and 6and a manufacturing method that does not use the spacer26, the efficiency with which the notched portions23are formed can be increased when the following condition is satisfied. That is, in the case that adjacent second members22are arranged parallel to each other while being brought into contact with each or with prescribed intervals provided therebetween, it is sufficient if there is an arrangement mode in which at least some of the constituent surfaces of the notched portions23are substantially flush with each other.

Second Embodiment

A second embodiment will now be described with reference toFIGS. 7 to 9. In the first embodiment, the shape of the notched portions23is the same in the group of the mass bodies HM belonging to the same area, but the positions of the notches (positions of formation) differ from each other. In contrast, in the present embodiment, the position of the notched portions23is the same in the group of the mass bodies HM belonging to the same area, but the amounts of notching (size) of the notches differ from each other. In particular, depths of the notches differ from each other. In this embodiment, each of the notched portions23is unfilled and free of any materials.

FIG. 7is a view illustrating differences in the shapes of the second members22for each area.FIG. 8is a plan view of the workpiece220after forming the notched portions23.FIG. 9is a rear view of the workpiece220during the formation of the notched portions23.FIGS. 7, 8, and 9respectively correspond toFIGS. 3, 4, and 5.

The divisions of the group A, group B, and group C are the same as in the example ofFIG. 3. The common portions25and the unique portions24, if there are no notched portions23, are all the same, as in the first embodiment. Thus, gross differences in the moments of inertia are provided for each group as a result of the differences in the shapes of the unique portions24. On the other hand, the setting of minute differences in the moments of inertia within the same group is achieved by the amount of notching of the notched portions23.

First, the distance from the hammer pivot fulcrum15to the center of gravity G (corresponding to the distance D1inFIG. 2) is shared between the mass bodies HM belonging to the same area. The side surfaces23a,23bof each of the notched portions23are essentially parallel to the axial direction of the hammer pivot fulcrum15. The bottom surface23cof each notched portion23is inclined such that the treble sides thereof are closer to the lower side. That is, the notched portions23are deeper toward the treble side. As a result, although the shape of the second member22excluding the notched portion23is the same within the same group, the moment of inertia is lower in the mass body HM whose corresponding pitch is higher.

Next, using Group A as an example, the method for manufacturing the second member22of the mass body HM will be described with reference toFIGS. 8 and 9. The configuration and the fixing method of the workpiece220are the same as in the first embodiment. As shown inFIG. 8, the operator moves the rotary cutter18relative to the workpiece220to thereby form the continuous groove230in a straight line on the workpiece220. At this time, as shown inFIGS. 8 and 9, the operator sets the direction of movement of the cutter18such that the rear end surface of the workpiece220and the direction of formation of the continuous groove230are parallel, and such that the notch depth becomes deeper toward the treble side. After forming the continuous groove230, the operator cuts out a plurality of the second members22by cutting the workpiece220for each designed thickness of the second member22. The subsequent steps are the same as in the first embodiment.

In a state in which the mass bodies HM are arranged in the aforementioned keyboard1, the side surfaces23a,23bfrom among the constituent surfaces of each notched portion23are essentially parallel to the arrangement direction of the second members22and the axial direction of the hammer pivot fulcrum15. On the other hand, of the constituent surfaces of each notched portion23, the bottom surface23cis not parallel to the arrangement direction of the second members22or the axial direction of the hammer pivot fulcrum15.

It is assumed that a group of mass bodies HM belonging to the same area (group) have been removed from the frame10and that the group of mass bodies HM have been arranged parallel to each other such that the hammer pivot fulcrums15thereof are concentric (or such that the rear end positions of the common portions25are coincident). Here, there is a prescribed arrangement mode in which the constituent surfaces (side surfaces23a,23b, bottom surface23c) of each of the notched portions23are substantially flush. For example, as in the relationship shown inFIG. 8, if the group of mass bodies HM are arranged parallel to each other without intervals such that the second members22are in contact with each other, not only do the side surfaces23a,23bbecome substantially flush but also the bottom surface23cof each notched portion23. If the group of mass bodies HM are arranged parallel to each other while prescribed intervals are maintained in the same manner as shown inFIG. 2, the side surfaces23a,23bof each notched portion23become substantially flush, but the bottom surfaces23cdo not.

According to the present embodiment, differences in the moments of inertia between the mass bodies HM belonging to the same area can be generated as a result of differences in the amount of notching (depths) of the notched portions23. Thus, it is possible to easily provide various types of mass bodies HM that have different moments of inertia. Moreover, since the notched portions23of the second members22can be formed all at once at the stage of the workpiece220, the manufacturing efficiency is high. Thus, the same effect as in the first embodiment can be achieved, with respect to being able to facilitate the manufacture of a plurality of the mass bodies HM that have different moments of inertia.

The continuous groove230can be formed after producing one group's worth of the second members22in the present embodiments as well, in the same manner as the modified example shown inFIG. 6. At this time, spacers may or may not be used. Regardless of whether spacers are used, in the case that adjacent second members22are arranged parallel to each other, as long as the arrangement intervals are appropriately set, there is an arrangement mode in which at least some of the constituent surfaces of the notched portions23are substantially flush with each other.

In each of the embodiments described above, the notched portions23can be formed in all of the mass bodies HM belonging to the same area in a range from the lowest pitch to the highest pitch. However, it is not necessary for the notched portions23to be formed in all of the mass bodies HM belonging to the same area. For example, the notched portion23can be formed in each of the mass bodies HM in a range from a pitch greater than or equal to the lowest pitch of the same area to the highest pitch of the same area. Thus, notched portions23need not be present in a prescribed number of mass bodies HM beginning with the first mass body on the bass side.

In addition, various modified examples as shown inFIGS. 10 to 12are conceivable.FIG. 10is a partial side view of the mass body HM according to a modified example. As a result of forming the entire second members22so as to be embedded inside the first member21, the notched portion23is not exposed. The notched portion23is covered with a resin member, which contributes to corrosion prevention and increased durability. Insert molding was given as an example of a means to incorporate the second member22in the first member21, but the invention is not limited thereto, and any method, such as fitting, can be used. In addition, in the present embodiment, the first member21and the second member22are separate members, but the mass body HM can be configured as a single body. In addition, the material of the first member21is resin, and the material of the second member22is metal, but the materials are not limited thereto.

As in the second member22illustrated inFIG. 11, the direction of the opening of the notched portion23is not limited to the upward direction, and can be the forward, rearward, or downward direction. In addition, the shape of the notched portion23in a side view is not necessarily required to be shaped semi-rectangular, and can be C-shaped, U-shaped, arcuate, or polygonal. In addition, the notched portion23can be understood to be a groove or a hole. The notched portion23is not limited to being formed only on in the common portion25, and can be formed over a part of the unique portion24or a part of the first member21. In addition, a method was described in which the notched portions23are formed by cutting a workpiece with a rotary cutter, but the invention is not limited thereto. For example, when holes of different size are formed as the notched portions23, the notched portions23can be formed by a desired method, such as boring holes in the workpiece with a drill.

In the examples shown inFIGS. 4 and 9, an example was presented in which the moments and mass are changed by linearly changing position and depth, but such linear changes are not essential. For example, as shown by the double-dot chain lines230-1and230-2inFIGS. 4 and 9, the position and depth can be changed in a curvilinear manner. The double-dot chain line230-1inFIG. 4shows an example of the positions of the side surfaces23aof the notched portions23. That is, the arrangement mode in which at least some of the constituent surfaces of each of the notched portions do not become parallel to the arrangement direction of the group of the mass bodies, and the mode in which the side surfaces governing the contour of the notch shape of the notched portion do not become parallel to the arrangement direction are not limited to a plane-to-plane relationship, but also include a plane-to-curved surface relationship, or a curved surface-to-curved surface relationship.

In the embodiments described above, the mass bodies belonging to different areas among the plurality of areas have unique portions that have different shapes from each other, as well as common portions that have the same shape if there are no notched portions, but the configuration may be one in which there is no distinction between a unique portion and a common portion.

According to the embodiments described above, a keyboard1includes a frame10, a plurality of keys K, and a plurality of hammers HM. The plurality of keys K are arranged in parallel to each other and pivotally supported with respect to the frame10about a key pivot fulcrum11. The plurality of hammers HM are arranged in parallel to each other and pivotally supported with respect to the frame10about a hammer pivot fulcrum15. The plurality of hammers MC are connected to the plurality of keys K to pivot in conjunction with a corresponding one of the plurality of keys K on a one-to-one basis to define a plurality of key-hammer arrangements arranged in parallel to each other. At least some of the plurality of key-hammer arrangements include notched portions23being arranged in order from a pitch, which is equal to or greater than a lowest pitch, to a highest pitch. The notched portions23are different from each other in at least one of size, position, distance from the key pivot fulcrum11, or distance from hammer pivot fulcrum15.

It is not necessary that the second member22, which functions as a weight, be applied to the mass body HM that moves in conjunction with an operation of the key K. As shown inFIG. 12, a mass body in which a second member22K, on which a notched portion23K (embedded member) is formed, is embedded in the key K that is directly operated, can be the mass body of this disclosure. In this case, it is not necessary to provide the mass body HM that is interlocked with the key K. In addition, a hammer was described as an example of an interlocking member that moves in conjunction with the key K, but other members can be used. Thus, the mass body HM can be a plurality of the keys K that are directly operated, a plurality of interlocking members that pivot in conjunction with the corresponding key K, or embedded in such keys or interlocking members (embedded members in the plurality of keys or embedded members in the plurality of interlocking members).

When this disclosure is applied, the “keyboard” includes at least a plurality of the keys K, but can also include a plurality of the mass bodies HM. In addition, the “keyboard” can be called a keyboard device or a keyboard unit.

This disclosure was described above based on preferred embodiments, but this disclosure is not limited to the above-described embodiments, and includes various embodiments that do not depart from the scope of the invention. Some of the above-described embodiments may be appropriately combined.