Keyboard device for electronic musical instrument

A keyboard device includes hammers 16w, 16b that rock with the rocking movement of plural white and black keys 11w, 11b. The plural white and black keys 11w, 11b include drive units that drive the hammers 16w, 16b. The drive unit is provided on a front end of the key. A positional relationship between a plane including a key support portion of each white key 11w and black key 11b and the front end of the white key 11w and black key 11b, and a top face of each white key 11w and black key 11b is set such that the top faces of the plural white keys 11w and black keys 11b are located on the same plane, when the rocking angles of the plural white keys 11w and black keys 11b reach a predetermined angle respectively.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a keyboard device for an electronic musical instrument such as an electronic organ, an electronic piano, and the like.

2. Description of the Related Art

There has conventionally been known a keyboard device for an electronic musical instrument described in Japanese Patent No. 3074794. In this keyboard device described above, a key touch feeling (reaction force against a key depression/release operation) on a front end of a key, to which a higher pitch is assigned, is set lighter in order to generate a key touch feeling similar to a key touch feeling of an acoustic piano. This keyboard device has plural hammers, each of which rocks through an engagement with the corresponding key so as to apply reaction force against the depression/release operation of the corresponding key. The plural hammers are common components. In this keyboard device, the length from the pivot point of the key, formed on a back end, to the front end of the key becomes gradually longer toward the keys on the high-pitched side from the keys on the low-pitched side. In addition, the position of the pivot point of each hammer is gradually shifted backward from the low-pitched side toward the high-pitched side, by which the distance from the pivot point of the key to the engagement position between the hammer and the key is set to be the same for all keys.

The conventional keyboard device described above has a stopper for restricting the rocking movement of the key, and the maximum depth during the key depression is the same for all keys. However, since the pivot point of each hammer is shifted in the longitudinal direction, the range of the rocking angle of each hammer is different among the assigned pitches. Therefore, it is necessary to set the position and performance of a rubber switch, which is pushed by the rocking movement of the hammer, to be different among the assigned pitches. In order that the height of the front end of each key and the tilt angle of each key during the key release and the key depression are set to be the same for all keys to make the appearance of the keyboard device similar to the appearance of an acoustic piano, the position and thickness of the stopper for restricting the rocking movement of each key have to be different among the assigned pitches. Accordingly, a large variety of components are needed, so that the productivity of the keyboard device is low.

SUMMARY OF THE INVENTION

The present invention is accomplished to solve the above-mentioned problem, and aims to reduce cost for the keyboard device, which creates a key touch feeling and appearance similar to those of an acoustic piano by shifting the position of the pivot point of each key in the longitudinal direction, and to enhance productivity of the keyboard device. For easy understanding of the present invention, a numeral of a corresponding portion in an embodiment is written in a parenthesis in the description below of each constituent of the present invention. However, each constituent of the present invention should not be construed as being limited to the corresponding portion indicated by the numeral in the embodiment.

In order to attain the foregoing object, the present invention provides a keyboard device for an electronic musical instrument, the keyboard device including: plural white keys and black keys (11w,11b) that are supported by a key support portion (Kw, Kb) in order that front ends thereof rock in the vertical direction by a key depression/release operation by a performer, each white key having an edge line extending in the longitudinal direction on a crossing portion of a side face and a top face, and each black key having an edge line extending in the longitudinal direction on a crossing portion of a lower side face and an upper side face tilting inward with respect to the lower side face, wherein a pitch is assigned to each of the plural white keys and black keys, each of plural white keys and each of black keys include an operation portion that is depressed and released by the performer, and a drive unit (11w1,11b1) extending downward on a front end of the operation portion, and a length from the front end of the operation portion to the key support portion is different among the plural white keys and black keys; plural hammers (16w,16b), each of which includes an engagement portion engaged with the drive unit of each of the plural white keys and the drive unit of each of the plural black keys, and each of which is supported by a hammer support portion (Hw, Hb) in order to rock with the rocking movement of each of the plural white keys and black keys; and a restricting member (20,21) that is arranged to extend in the direction of the arrangement of the plural white keys and black keys, and that restricts the rocking movement of the plural hammers in order to restrict the rocking range of the plural white keys and the plural black keys, wherein, when a first key out of the plural white keys and the plural black keys and a second key having the distance longer than the distance of the first key have a predetermined rocking angle respectively, the first key and the second key being both white keys or both black keys, a positional relationship between a plane including the key support portion of the first key and the front end of the operation portion of the first key, and the top face of the first key is set in order that the position of the front end of the operation portion of the first key in the vertical direction and in the longitudinal direction is the same as the position of the front end of the operation portion of the second key in the vertical direction and in the longitudinal direction, and the top face of the first key is in plane with the top face of the second key. In a state in which braking force for stopping the hammer by the restricting member is transmitted via the engagement portion between the key and the hammer, it is regarded that the rocking movement of the key is substantially restricted by the restricting member of the hammer.

In this case, it is preferable that the key support portion of the first key is located below a reference plane (S1, S3) including the key support portion of the second key and the front end of the second key in the state in which the second key is released, and when the first key and the second key are released, the front end of the operation portion of the first key is located posterior to the front end of the operation portion of the second key.

In this case, it is preferable that the first key and the second key are adjacent white keys, and the edge line of the black key between the first key and the second key is located between the top face of the first key and the top face of the second key, in a state in which the first key, the second key, and the black key are released.

In this case, it is preferable that the first key and the second key are adjacent white keys, and the edge line of the black key between the first key and the second key is located below the top face of the first key and the top face of the second key, in a state in which the first key, the second key, and the black key are depressed, and the rocking movements of the first key, the second key, and the black key are restricted. The state in which the rocking movement is restricted means the state in which the same load is applied to the front end of the white key and the front end of the black key to restrict the rocking movement of the keys. The present invention includes the case in which a part of the edge line of the black key on the front end is located below the top face of the first key and the top face of the second key.

In this case, it is preferable that the distance from the leading end to the hammer support portion of the plural hammers is the same for all of the plural hammers. Each of the plural hammers includes a mass member that becomes light from a low-pitched side toward a high-pitched side, and a key touch feeling becomes gradually light from the low-pitched side toward the high-pitched side. The mass member for the hammer for the white key is heavier than the mass member for the neighboring hammer for the black key. The length from the front end to the back end of the plural white keys becomes shorter toward the high-pitched side from the low-pitched side, and the length from the front end to the back end of the plural black keys becomes shorter toward the high-pitched side from the low-pitched side.

According to the keyboard device configured as described above, the appearance can be made close to the appearance of a keyboard on an acoustic piano without a need to adjust the height of the front end of the key for each key in the key released state and the key depression state. Therefore, the number of components can be reduced, compared to the case where the height of the front end of the key is adjusted for each key, whereby the cost for the keyboard device can be reduced. When the plural white keys and the black keys are depressed, and their rocking movement is restricted, in particular, the top face of the white key and the top face of the black key are located on the same plane, resulting in that the present invention can generate the appearance similar to the appearance of the acoustic piano in the key depression state. The rocking angle is an angle of the plane including the edge line of the key with the key released state being defined as a reference. The front end of the operation portion of the key from which the drive unit extends is a region where at least a part of a region on which the front end of the key passes when the key rocks and a part of a region on which the engagement portion between the drive unit and the hammer passes are superimposed in the longitudinal direction as viewed in a plane.

Another aspect of the present invention is that the distance between the plane including the edge line of the first key and the key support portion of the first key is set to be the same as the distance between the plane including the edge line of the second key and the key support portion of the second key. In this case, it is preferable that the positions of the key support portion of the first key and the key support portion of the second key are set to be the same. By virtue of this configuration, the part other than the part involved with the length of the key can be the same as much as possible. In addition, the support member (frame) for supporting the key can easily be designed. The support member is easily processed, whereby precision can be enhanced. When the distance between the plane including the edge line of the first key and the key support portion of the first key is set to be the same as the distance between the plane including the edge line of the second key and the key support portion of the second key, and the positions of the key support portion of the first key and the key support portion of the second key are set to be the same, the top face of the first key and the top face of the second key are located on the same horizontal plane in the key depression state. Consequently, the appearance similar to the keyboard of the acoustic piano can be generated.

DESCRIPTION OF THE PREFERRED EMBODIMENT

One embodiment of the present invention will be described below with reference to the drawings. In the description below, a side close to a performer is defined as a “front side”, while a side far from the performer is defined as a “rear side”. A high-pitched side is defined as a “right side”, while a low-pitched side is defined as a “left side”.

A keyboard device includes plural white keys11wand plural black keys11bas illustrated inFIGS. 1 to 3. A different pitch is assigned to each of plural white keys11wand each of plural black keys11b. In the present embodiment, one of “C3”, “D3”, . . . “C6” is assigned to the white keys11w, while one of “C#3”, “D#3”, . . . “B#5” is assigned to the black keys11b. The white keys11wand black keys11bare integrally formed to have a long shape by a synthetic resin. The white keys11ware configured such that the length thereof is gradually shorter toward the white key11won the high-pitched side from the white key11won the low-pitched side. The black keys11bare configured such that the length thereof is gradually shorter toward the black key11bon the high-pitched side from the black key11bon the low-pitched side. The back end of the black key11bis located posterior to the back end of the adjacent white key11w.

The white keys11w, each having a different assigned pitch, have different length in the longitudinal direction, but the other structures are the same. The black keys11b, each having a different assigned pitch, have different length in the longitudinal direction, but the other structures are the same. Each of the white keys11whas a width in the vertical direction smaller than that of the black key11b, and has a width in the lateral direction larger than that of the black key11b. The white key11wand the black key11bhave a hollow shape including a thin top wall extending in the longitudinal direction, and thin sidewalls extending downward from left and right ends of the top wall respectively, with no bottom.

Through-holes Kw and Kb that are opposite to each other are formed on the rear part of the sidewall of the white key11wand the black key11b. The distance from the through-holes Kw and Kb to the back end of each key is the same for all keys. The white key11wand the black key11bare supported by a key support portion13wand a key support portion13bof a later-described key frame12with the through-holes Kw and Kb.

The back end of the white key11wgoes into a casing of the electronic musical instrument, when the keyboard device is assembled to the electronic musical instrument. The portion of the white key anterior to the portion going into the casing is referred to as an apparent portion of the white key11w. An edge line is formed on the portion where the side face and the top face of the white key11wcross each other. The black key11bhas a portion projecting upward from the top face of the white key11win a state in which the black key11bis not depressed, and the adjacent white keys11ware not depressed. The projecting portion is referred to as an apparent portion of the black key11b. The portion lower than the apparent portion of the black key11bis referred to as a body. A performer depresses or releases the apparent portions of the white key11wand the black key11b. Specifically, the apparent portion corresponds to an operation portion in the present invention. The width of the apparent portion of the black key11bin the lateral direction becomes narrower toward the top end, and the width of the body in the lateral direction is the same for all black keys. An edge line is formed on the boundary between the lower end of the apparent portion of the black key11band the portion lower than the lower end of the apparent portion.

The key frame12has a top plate12aextending in the longitudinal direction and lateral direction. The position of the front end of the top plate12aat the low-pitched side and the position of the front end at the high-pitched side are the same, but the back end at the low-pitched side is located posterior to the back end at the high-pitched side. The key frame12also has a front plate12bvertically extending downward from the front end of the top plate12a, a bottom plate12chorizontally extending from the lower end of the front plate12b, and a front plate12dvertically extending upward from the front end of the bottom plate12c. The key frame12also includes a rear plate12evertically extending downward from the back end of the top plate12a, and a bottom plate12fhorizontally extending rearward from the lower end of the rear plate12e. The height of the lower surface of the bottom plate12cand the height of the lower surface of the bottom plate12fare the same. The keyboard device is supported by a frame FR of an electronic musical instrument by the structure in which the lower surface of the bottom plate12cand the lower surface of the bottom plate12fare brought into contact with the frame FR of the electronic musical instrument and fixed thereto. The above-described key support portion13wand the key support portion13bare formed to project upward from the upper surface of the top plate12a. The key support portion13bis located posterior to the adjacent key support portion13w. The key support portion13wand the key support portion13brespectively include two opposing plates, and a projection13w1and projection13b1that project inward. The projections13w1and13b1are fitted to the through-holes Kw and Kb respectively. Therefore, the white key11wand the black key11bare supported to be rotatable about the projections13w1and13b1, and their front ends can rock in the vertical direction with the through-holes Kw and Kb and the center axes of the projections13w1and the projections13b1being defined as a pivot center. The distance between the top face of the apparent portion of the white key11w(i.e., the plane including the right and left edge lines of the white key11w) and its pivot center in the vertical direction is the same for all white keys11w. The distance between the top face of the operation portion of the black key11b(i.e., the plane including the right and left edge lines of the black key11b) and its pivot center in the vertical direction is the same for all black keys11b.

A drive unit11w1extends downward from the front end of the apparent portion of the white key11w. The drive unit11w1has a hollow shape including a thin front wall extending in the vertical direction, and thin sidewalls extending rearward from left and right ends of the front wall, and is open to the rear. The lower end of the drive unit11w1is closed by a lower end wall. The length of the drive unit11w1in the vertical direction is the same for all white keys11w. On the other hand, the black key11walso has a drive unit11b1same as the drive unit11w1of the white key11w. The length of the drive unit11b1in the vertical direction is also the same for all black keys11b.

The positions of the drive units11w1of the plural white keys11win the longitudinal direction are the same, and the positions of the lower end walls of the drive units11w1in the vertical direction are the same, when the plural white keys11ware released. The positions of the drive units11b1of the plural black keys11bin the longitudinal direction are the same, and the positions of the lower end walls of the drive units11b1in the vertical direction are the same, when the plural black keys11bare released. In other words, the drive units11w1and the drive units11b1are arranged side by side in the lateral direction.

Since the length of the drive unit11w1in the vertical direction is the same for all white keys11w, and the positions of the lower ends of the drive units11w1in the vertical direction and in the longitudinal direction are the same during the key release, the position of the front end of the apparent portion in the vertical direction is almost the same as illustrated inFIG. 4. As illustrated inFIG. 5, the white key11wtilts such that the back end is lower than the front end during the key release, and the front end of the white key11whaving the shorter length in the longitudinal direction is located posteriorly. In the present embodiment, the length in the longitudinal direction becomes gradually shorter from the white key11won the low-pitched side toward the white key11won the high-pitched side. Therefore, the front end of the apparent portion of the white key11won the high-pitched side is located posteriorly. In a state in which two adjacent white keys11wand the black key11bbetween the two adjacent white keys11ware released, the edge line R of the black key11bis located below the top face of one on the low-pitched side of the two white keys11w, and above the top face of one on the high-pitched side of the two white keys11w.

In a state in which the white key11w(C6) to which a pitch “C6” is assigned and the white key11w(B5) to which a pitch “B5” is assigned are released, for example, the front end of the white key11w(C6) is located slightly posterior to the front end of the white key11w(B5) (seeFIG. 5). The pivot center of the white key11w(C6) is located below a plane S1including the pivot center of the white key11w(B5) and the front end of the apparent portion of the white key11w(B5).FIG. 5illustrates the posture when the white key11w(B5) and the white key11w(C6) are released and depressed. Specifically, the white key11w(B5) that is released is indicated by a bold broken line, and the white key11w(B5) that is depressed is indicated by a thin broken line. The white key11w(C6) that is released is indicated by a bold solid line, and the white key11w(C6) that is depressed is indicated by a thin solid line. InFIG. 5, the length of the white key11w(C6) and the length of the white key11w(B5) are greatly different in order to indicate the difference between the positions of the front ends of the apparent portions of the white keys11win the longitudinal direction, each having a different length in the longitudinal direction. However, the difference between the lengths of the adjacent keys is actually small, so that the difference in height between the white keys11wis also small. InFIG. 5, the shape of each key is simplified in order to simplify the drawing.

As described above, the tilt angle of the white key11whaving the shorter length in the longitudinal direction is larger in the key release state. The positional relationship between the plane including the pivot center and the front end of the apparent portion and the top face for each white key11wis set such that the top faces of the plural white keys11ware horizontal when the plural white keys11ware depressed, and their rocking angles from the key release state reach the same predetermined rocking angle (i.e., when the hammer13wis brought into contact with a buffer member20bto restrict the rocking movement of the white key11was described later). In other words, the angle of the top face with respect to the plane including the pivot center and the front end of the apparent portion is set for each of the white keys11w. The position of the front end of the apparent portion of the white key11win the vertical direction and in the longitudinal direction is the same for all white keys11win the state in which the top face of each of the plural white keys11wis horizontal.

Since the length of the drive unit11b1in the vertical direction is the same for all black keys11b, and the positions of the lower ends of the drive units11b1in the vertical direction and in the longitudinal direction are the same during the key release as described above, the position of the front end of the apparent portion in the vertical direction is almost the same, when the black key11bis released. The black key11btilts such that the back end is lower than the front end during the key release, and the key having the shorter length in the longitudinal direction has the larger tilt angle. The front end of the black key11bhaving the shorter length in the longitudinal direction is located posteriorly. In the present embodiment, the length in the longitudinal direction becomes gradually shorter from the black key11bon the low-pitched side toward the black key11bon the high-pitched side. Therefore, the front end of the apparent portion of the black key11bon the high-pitched side is located posteriorly. For example, in a state in which the black key11b(G#5) to which a pitch “G#5” is assigned and the black key11b(A#5) to which a pitch “A#5” is assigned are released, the front end of the black key11b(A#5) is slightly posterior to the front end of the apparent portion of the black key11b(G#5) as illustrated inFIG. 6. The pivot center of the black key11b(A#5) is located below a plane S2including the pivot center of the black key11b(G#5) and the front end of the apparent portion of the black key11b(G#5).FIG. 6illustrates the posture when the black key11b(G#5) and the black key11b(A#5) are released and depressed. Specifically, the black key11b(G#5) that is released is indicated by a bold broken line, and the black key11b(G#5) that is depressed is indicated by a thin broken line. The black key11b(A#5) that is released is indicated by a bold solid line, and the black key11b(A#5) that is depressed is indicated by a thin solid line. InFIG. 6, the length of the black key11b(G#5) and the length of the black key11b(A#5) are greatly different in order to indicate the difference between the height of the front ends of the apparent portions of the black keys11b, each having a different length in the longitudinal direction. However, the difference between the lengths of the adjacent keys is actually small, so that the difference in height between the black keys11bis also small. InFIG. 6, the shape of each key is simplified in order to simplify the drawing.

The positional relationship between the plane including the pivot center and the front end of the apparent portion and the top face for each black key11bis set such that the top faces of the plural black keys11bare horizontal when the plural black keys11bare depressed, and their rocking angles from the key release state reach the same predetermined rocking angle (i.e., when the hammer13bis brought into contact with a buffer member21bto restrict the rocking movement of the black key11bas described later). In other words, the angle of the top face with respect to the plane including the pivot center and the front end of the apparent portion is set for each of the black keys11b. The position of the front end of the apparent portion of the black key11bin the vertical direction and in the longitudinal direction is the same for all black keys11bin the state in which the top face of each of the plural black keys11bis horizontal.

The lower ends of the drive unit11w1and the drive unit11b1are respectively engaged with front ends of hammers16wand16bin the opening formed between the front plate12band the front plate12d. In the key released state, contact portions Pw1and Pb1between the lower ends of the drive unit11w1and the drive unit11b1and the front ends of the hammers16wand16bare located on the same straight line extending respectively in the lateral direction (the direction parallel to the key arrangement direction).

The hammer16wincludes a base16w1made of synthetic resin, a connection rod16w2made of metal, and a mass member16w3. Like the hammer16w, the hammer16bincludes a base16b1, a connection rod16b2, and a mass member16b3. The base16w1and the base16b1are plate-like members, and formed with through-holes Hw and Hb, respectively, from the right side face to the left side face. The base16w1is longer than the base16b1in the longitudinal direction. A hammer support portion18wand a hammer support portion18bare formed to project downward from the lower surface of the top plate12a. The hammer support portions18wand18bare formed to have two opposing plates, and respectively have projections18w1and18b1projecting inward. The projections18w1and18b1are respectively fitted to the through-holes Hw and Hb. With this structure, the bases16w1and16b1are supported to be rotatable about the projections18w1and18b1. Specifically, the hammer16wand the hammer16bare supported such that the front ends and the back ends can be rocked in the vertical direction. The positions of the hammer support portion18wand the hammer support portion18bin the longitudinal direction and in the vertical direction are the same for all hammers. Specifically, plural hammer support portions18wand18bare arranged side by side in the lateral direction, wherein the positions of the pivot center of the hammers16wand16bin the longitudinal direction and in the vertical direction are the same for all hammers16wand16b. In other words, the pivot centers of the hammers16wand16bare located on the same straight line extending in the lateral direction.

The base16w1includes a pair of leg portion Fw1and leg portion Fw2on its front end. The upper leg portion Fw1is formed to be shorter than the lower leg portion Fw2. Like the base16w1, the base16b1includes a pair of leg portion Fb1and leg portion Fb2on its front end. An elongated slit-like opening12b1extending in the vertical direction is formed on the front plate12bfor each of the hammers16wand16b. The front end of each hammer16wand the front end of each hammer16bproject forward of the front plate12bthrough the opening12b1. The wall of the lower end of the drive unit11w1enters between the leg portions Fw1and Fw2, while the wall of the lower end of the drive portion11b1enters between the leg portions Fb1and Fb2. The leg portions Fw1and Fb1enter between the walls of the lower ends of the drive units11w1and11b1and intermediate walls that form gaps with the walls of the lower ends in the drive units11w1and11b1. A shock absorbing material such as rubber, urethane, or felt is fitted and fixed on the wall of the lower end of each of the drive units11w1and11b1. The shock absorbing material absorbs shock caused by the collision between the lower end of the drive unit11w1and the upper surface of the leg portion Fw2, the collision between the lower end of the drive unit11b1and the upper surface of the leg portion Fb2, the collision between the lower end of the drive unit11w1and the lower surface of the leg portion Fw1, and the collision between the lower end of the drive unit11b1and the lower surface of the leg portion Fb1.

The front end of the connection rod16w2and the front end of the connection rod16b2are assembled to the back end of the base16w1and the back end of the base16b1, respectively. The connection rods16w2and16b2extend rearward. The position of the back end of the connection rod16w2and the position of the back end of the connection rod16b2in the longitudinal direction are the same. The mass member16w3and the mass member16b3, described later, are assembled to the back end of the connection rod16w2and the back end of the connection rod16b2, respectively. The distance from the leading ends to the hammer support portions (the pivot centers) of the hammers16wand16bis the same for all hammers16wand16b.

As described above, the position of the pivot point of the key is different depending upon the assigned pitch. Therefore, the distance from the pivot center of the white key11wto the contact portion Pw1of the leg portion Fw2and the drive unit11w1is different depending upon the assigned pitch. The distance from the pivot center of the black key11bto the contact portion Pb1of the leg portion Fb2and the drive unit11b1is also different depending upon the assigned pitch. Therefore, if the masses of the mass members for all hammers are equal, a key touch feeling is heavier on the middle-pitched part than on the low-pitched part, and the key touch feeling is heavier on the high-pitched part than on the middle-pitched part, on key depression/release operation positions W0and B0, because of the principle of leverage.

In addition, in this case, the key touch feeling of the white keys11wand the black keys11bin each range is not equal. Specifically, the key touch feeling of the key11bis heavier than the key touch feeling of the adjacent two white keys11w. In view of this, the mass of the mass member16w3and the mass of the mass member16b3are adjusted for each key as illustrated inFIG. 7. Specifically, as illustrated in a characteristic curve indicating the masses of the mass members16w3and16b3in the order of pitches, the masses of the mass members16w3and16b3are adjusted such that the characteristic curve of the mass member16w3and the characteristic curve of the mass member16b3are parallel downward-sloping curves, wherein the characteristic curve of the mass member16b3is located below the characteristic curve of the mass member16w3. In other words, the mass member16w3for the white key11wis heavier than the mass member16b3for the neighboring black key11b. Thus, as illustrated by a chain line inFIG. 8, the key touch feeling on the key depression/release operation positions W0and B0becomes gradually lighter toward the high-pitched side from the low-pitched side. Therefore, as illustrated by a broken line inFIG. 8, the key touch feeling on key depression/release operation positions W1and B1located posterior to the key depression/release operation positions W0and B0by a distance d also becomes gradually lighter toward the high-pitched side from the low-pitched side. Since the length of the key to which a higher pitch is assigned is shorter, the difference between the key touch feeling on the key depression/release operation positions W0and B0and the key touch feeling on the key depression/release operation positions W1and B1becomes larger toward the high-pitched side from the low-pitched side. Specifically, the difference in the key touch feeling caused by the longitudinal difference of the key depression/release operation position is small on the low-pitched side, moderate in the middle-pitched side, and large on the high-pitched side.

When the white key11wand the black key11bare released, the front ends of the hammers16wand16bdisplace upward due to their own weight of the hammers16wand16b. In this case, the drive unit11w1and the drive unit11b1are biased upward by the leg portion Fw2and the leg portion Fb2respectively, whereby the front ends of the white key11wand the black key11bdisplace upward. On the other hand, when the white key11wand the black key11bare depressed, the lower surfaces of the drive unit11w1and the drive unit11b1press the upper surfaces of the leg portion Fw2and the leg portion Fb2respectively, whereby the front ends of the hammer16wand the hammer16brespectively displace downward.

A lower-limit stopper20is provided to the key frame12. During the key depression, the lower-limit stopper20is brought into contact with the upper surfaces of the mass member16w3and the mass member16b3of the hammer16wand the hammer16bso as to restrict the upward displacement of the back ends of the hammer16wand the hammer16b, thereby restricting the downward displacement of the front ends of the white key11wand the black key11b. The lower-limit stopper20includes a stopper rail20aand a buffer material20b. The stopper rail20aprotrudes downward from the lower surface at the middle of the top plate12a, and extends in the lateral direction. The stopper rail20ais located above the mass member16w3and the mass member16b3. The projection amount of the stopper rail20afrom the lower surface of the top plate12aon the contact portion between the stopper rail20aand each hammer is constant in the lateral direction. The buffer material20bis fixed to the lower end surface of the stopper rail20a. The buffer material20bis a long member made of a shock-absorbing material such as rubber or felt. The sectional shape of the buffer material20bis uniform from one end to the other end.

An upper-limit stopper21is provided to the middle portion of the frame FR. During the key release, the upper-limit stopper21is brought into contact with the lower surfaces of the mass member16w1and the mass member16b1of the hammer16wand the hammer16bso as to restrict the downward displacement of the back ends of the hammer16wand the hammer16b, thereby restricting the upward displacement of the front ends of the white key11wand the black key11b. Like the lower-limit stopper20, the upper-limit stopper21includes a stopper rail21aand a buffer material21b. Specifically, the stopper rail21aalso extends in the lateral direction, and the projection amount thereof from the frame FR is constant in the lateral direction. The buffer material21bis fixed on the upper surface of the stopper rail21a. Like the buffer material20b, the sectional shape of the buffer material21bis uniform from one end to the other end. The stopper rail20aand the stopper rail21amay continuously extend in the lateral direction, or may discontinuously extend. The stopper rail20aand the stopper rail21amay be formed integral with the top plate12aand the frame FR respectively, or may be formed as separate components and assembled to the top plate12aand the frame FR respectively.

In the state in which the white key11wand the black key11badjacent to the white key11ware depressed respectively by the same depression force, and their rocking movement is restricted, the edge line R of the black key11bis located below the top face of the white key11w. The buffer member20band the buffer member21bhave elasticity. Therefore, when the key is depressed more after the hammer is brought into the buffer member during the key depression, the buffer member is elastically deformed, so that the front end of the key slightly displaces downward.

A switch drive unit AC1is provided on the lower surface of each of the white key11wand the black key11bon the middle part. The switch drive unit AC1is a plate-like member extending in the vertical direction in each of the white key11wand the black key11b, and the lower end surface of the switch drive unit AC1is brought into contact with the upper surface of a switch SW1. The switch SW1is provided for each key. The switch SW1is pressed by the corresponding key to detect whether the corresponding key is depressed or released. Specifically, when the switch SW1is depressed by the key, a rubber main body is deformed to make two contacts, which are formed on a circuit board23, short-circuit, thereby being turned ON. The circuit board23extends in the lateral direction. A through-hole penetrating from the upper surface to the lower surface is formed on the circuit board23. The through-hole corresponds to a boss24formed integral with the upper surface of the top plate12a. When a screw is threaded to the boss24through the through-hole, the circuit board23is fixed to the key frame12. The main bodies of the plural switches SW1, each corresponding to each key, are arranged on the upper surface of the circuit board23in the lateral direction. The position of the switch SW1for the white key11wand the position of the switch SW1for the black key11bin the longitudinal direction are the same. A distance Lw1from the front end of the white key11wto the switch SW1in the longitudinal direction is within 30% of the distance Lw2from the front end of the white key11wwith the highest pitch to the through-hole Kw, and a distance Lb1from the front end of the apparent portion of the black key11bto the switch SW1is within 30% of the distance Lb2from the front end of the apparent portion of the black key11bwith the highest pitch to the through-hole Kb. The switch SW1for the white key11wand the switch SW1for the black key11bmay be arranged side by side in the lateral direction, and the positions of both switches in the longitudinal direction may be shifted.

Key guides25wand25bfor guiding the rocking movement of the white key11wand the black key11bare formed to project upward from the top surface at the front end of the top plate12a. The key guide25wis inserted into the white key11wfrom below, and during the key depression and key release, the side face of the key guide25wand the inside face of the sidewall of the white key11ware in sliding contact with each other. This structure can prevent a slight displacement of the white key11win the lateral direction during the key depression and key release. The key guide25bis inserted into the black key11bfrom below, and during the key depression and key release, the side face of the key guide25band the inside face of the sidewall of the black key11bare in sliding contact with each other. This structure can prevent a slight displacement of the black key11bin the lateral direction during the key depression and key release.

In the keyboard device having the configuration described above, the appearance can be made close to the appearance of a keyboard on an acoustic piano without a need to adjust the height of the front end of the key for each key in the key released state and the key depression state. When the plural white keys11wand the black keys11bhave the maximum depth during the key depression, the top faces of the white keys11wand the black keys11bare horizontal. Therefore, the appearance similar to the appearance of the acoustic piano in the key depression state can be created. Accordingly, the number of components can be reduced, compared to the case where the height of the front end of the key is adjusted for each key, whereby the cost for the keyboard device can be reduced. The front end of the white key11wis gradually located posteriorly from the white key11won the low-pitched side toward the white key11won the high-pitched side during the key release, and the front end of the black key11bis gradually located posteriorly from the black key11bon the low-pitched side toward the black key11bon the high-pitched side during the key release. Specifically, the difference in the positions of the front end between the adjacent white keys11wand between the adjacent black keys11bin the longitudinal direction is small in the key released state. Accordingly, the present embodiment can create comfortable appearance in the key released state.

The distance from the top face of the apparent portion of the white key11wto the pivot center is the same for all white keys11w, and the distance from the top face of the body of the black key11bto the pivot center is the same for all black keys11b. Accordingly, when the through-holes Kw and Kb are formed in a different process after a process of molding the outer shape of the white key11wand the black key11b, the different process can commonly be carried out for all keys to enhance productivity of the keys.

All components of the hammer16w, except for the mass member16w3, are the same for all hammers16w. In addition, all components of the hammer16b, except for the mass member16b3, are the same for all hammers16b. Accordingly, the variety of the components can be reduced, so that the cost for the keyboard device can be reduced. The positions of the pivot centers of the hammers in the longitudinal direction and in the vertical direction are the same for all hammers, and the positions of the upper-limit stopper21and the lower-limit stopper20in the longitudinal direction and in the vertical direction are the same for all hammers. Therefore, the upper-limit stopper21and the lower-limit stopper20can easily be assembled. The number of components can be reduced, compared to the case in which the stopper is provided for each hammer, resulting in that the cost for the keyboard device can be reduced. As described above, the positions of the pivot centers of the hammers and the positions of the upper-limit stopper21and the lower-limit stopper20in the longitudinal direction and in the vertical direction are the same for all hammers. Therefore, the ranges of the rocking angle of the hammers can be the same for all hammers.

In the present embodiment, when the white key11wis assembled to the key frame12, the wall of the lower end of the drive unit11w1has to be inserted between the leg portion Fw1and the leg portion Fw2. When the black key11bis assembled to the key frame12, the wall of the lower end of the drive unit11b1has to be inserted between the leg portion Fb1and the leg portion Fb2. In the present embodiment, the positions of the contact portions Pw1in the longitudinal direction and in the vertical direction during the key release are the same for all white keys11wand all hammers16w. With this structure, the walls of the lower ends of the drive units11w1for the plural white keys11ware easy to be simultaneously inserted between the leg portions. The positions of the contact portions Pb1in the longitudinal direction and in the vertical direction during the key release are the same for all black keys11band all hammers16b. With this structure, the walls of the lower ends of the drive units11b1for plural black keys11bare easy to be simultaneously inserted between the leg portions. Specifically, plural white keys11wand black keys11bcan be assembled at a time, whereby an assembling property for assembling the keys to the key frame12can be enhanced.

Since the ranges of the rocking angles of the hammers are the same for all hammers, the rocking range of the front end of the apparent portion of the white key11wis the same for all white keys11w. The rocking range of the front end of the apparent portion of the black key11bis also the same for all black keys11b. In the present embodiment, the distances Lw1and Lb1are set to be sufficiently smaller than the distances Lw2and Lb2respectively. Therefore, a performer is easy to play the keyboard device.

Plural switches SW1, each corresponding to each key, are arranged side by side in the lateral direction. The maximum depth of the front end of each key during the key depression is almost the same for all white keys11was described above. Therefore, if the switches SW1are arranged side by side in the lateral direction near the front end of the white key11w, the depth of the key during the key depression when the ON/OFF state of each switch SW1is changed is almost the same. Therefore, this can realize that the switches SW1for all white keys11whave the same characteristics. Like the switches SW1for the white keys11w, the characteristics of the switches SW1for all black keys11bcan be the same. Specifically, not only the variety of the components can be reduced to reduce the cost for the keyboard device, but also the key depression/release state of each white key11wand each black key11bcan be detected respectively by the same process in the electronic musical instrument to which this keyboard device is applied. The circuit board23including the contacts of the plural switches SW1is provided to extend in the lateral direction. Therefore, the assembling property for the assembling operation can be enhanced, compared to the case in which the switch SW1is assembled for each key.

Upon embodying the present invention, the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the scope of the present invention.

For example, instead of the switch SW1, or in addition to the switch SW1, an optical sensor, a magnetic sensor, a capacitance sensor, or a pressure-sensitive sensor may be used to detect whether the key is depressed or released.

In the present embodiment, the pivot centers of the hammers16wand the hammers16bare formed on the middle part of the respective hammers16wand16b, for example. The engagement portions between the white key11wand the hammer16was well as between the black key11band the hammer16bare formed on the front end of the hammer16wand the front end of the hammer16b, respectively. However, the pivot center of each hammer and the position of the engagement portion are not limited to those described in the above embodiment. For example, the pivot centers may be formed on the back end of the hammer16wand the back end of the hammer16b. The engagement portions may be formed on the middle part of the hammer16wand on the middle part of the hammer16b, and the mass member16w3and the mass member16b3may be mounted on the front end of the hammer16wand the front end of the hammer16brespectively. In this case, the front ends of the hammer16wand the hammer16bare biased upward by an elastic member such as a spring or rubber during the key release. In this case too, the pivot centers of the respective hammers and the engagement portions may be arranged side by side in the lateral direction, and the stopper for restricting the rocking movement of the hammers16wand16bmay be arranged in the lateral direction. With the configuration in which the front ends of the hammers16wand16brock in the vertical direction about the back ends of the hammers16wand16bas described above, the effect same as that of the above-mentioned embodiment can also be obtained.

For example, in the present embodiment, the mass member16w3and the mass member16b3are mounted to the back ends of the connection rod16w2and the connection rod16b2. However, the mass member16w3and the mass member16b3are not mounted, but the leading ends of the connection rod16w2and the connection rod16b2may be folded back to the front so as to concentrate the mass on the back ends of the hammer16wand the hammer16b. By adjusting the length of the folded portion, the mass at the back ends of the hammer16wand the hammer16bmay be adjusted.

In the embodiment described above and its modifications, the masses of the mass member16w3and the mass member16b3are adjusted to make the key touch feeling on the front end of the key gradually light toward the keys on the high-pitched side from the keys on the low-pitched side. However, the present invention is not necessarily configured as described above. The key touch feeling on the front end of the key in each range may be set to be the same, and the key touch feeling may be made light in a stepwise manner for each range toward the high-pitched range. It may also be configured such that the key touch feeling may become light in the order of pitches in only a certain range. Alternatively, it may be configured such that the key touch feeling may be set to be the same for all keys.

In the embodiment described above and its modifications, the length of the white key11wbecomes gradually shorter toward the white keys11won the high-pitched side from the white keys11won the low-pitched side, while the length of the black key11bbecomes gradually shorter toward the black keys11bon the high-pitched side from the black keys11bon the low-pitched side. However, the present invention is not necessarily configured as described above. The positions of the pivot centers of plural keys may be shifted in the longitudinal direction, and the positions of the respective portions for these keys may be set to be the same. For example, the whole range is divided into plural ranges, and the length of each of the keys belonging to each of the divided ranges may be set to be the same (i.e., the positions of the pivot centers of the keys in the longitudinal direction and in the vertical direction are set to be the same), while the length of the keys may be set to be different among the divided ranges. The positions of the respective portions in each of the divided plural ranges may be set to be the same. According to this configuration, the effect same as the above-mentioned embodiment can be obtained.

In the embodiment and its modification described above, the distance from the top face of the apparent portion of the white key11wto its pivot center is the same for all white keys11w. The distance from the top face of the body of the black key11bto its pivot center is the same for all black keys11b. The height of the pivot center is the same for all keys. However, the distance from the top face of the apparent portion of the white key11wto its pivot center, the distance from the top face of the body of the black key11bto its pivot center, and the height of the pivot center may be different for each key. Specifically, the distance from the top face of the apparent portion of the white key11wto its pivot center, and the height of the pivot center may be set such that the top faces of the apparent portions of the plural white keys11ware located on the same plane on any rocking position within the rocking range of the plural white keys11w. The distance from the top face of the apparent portion of the black key11bto its pivot center, and the height of the pivot center may be set such that the top faces of the apparent portions of the plural black keys11bare located on the same plane on any rocking position within the rocking range of the plural black keys11b.

The top faces of the white keys11wduring the key release may be located on the same plane, although this structure creates an appearance slightly different from the appearance of an acoustic piano. The top faces of the black keys11bduring the key release may be located on the same plane. In this case, when two keys having different length are compared, the pivot center of the shorter key may be located in the planes S1and S3(seeFIGS. 5 and 6) of the longer key.

In the embodiment described above and its modifications, the distance from the leading end to the hammer support potion of each of the hammers16wand16bin the longitudinal direction is set to be the same. However, the distance from the leading end to the hammer support potion of each of the hammers16wand16bmay be set to be gradually shorter toward the high-pitched side from the low-pitched side. In this case, the rate of change of the distance from the leading end to the hammer support potion of each of the hammers16wand16bfrom the low-pitched side toward the high-pitched side may be set constant, and the lower-limit stopper20and the upper-limit stopper21on the high-pitched side may be arranged anterior to the lower-limit stopper20and the upper-limit stopper21on the low-pitched side. Specifically, the lower-limit stopper20and the upper-limit stopper21may be arranged diagonally, as viewed on a plane, in order that the ranges of the rocking angle of the hammers are the same for all hammers. With this structure, the number of components can be reduced, and the cost for the keyboard device can be reduced, compared to the case in which the stopper is provided for each hammer.

In the embodiment described above and its modifications, the white key11wand the black key11bare supported by the key support portions13wand13bof the key frame12by fitting the projections13w1and13b1to the through-holes Kw and Kb respectively so that the front ends of the white key11wand the black key11bcan rock in the vertical direction. However, the white key11wand the black key11bcan be mounted on the key frame12by using various supporting mechanisms, if the white key11wand the black key11bare supported by the key frame12so that the front ends of the white key11wand the black key11bcan rock in vertical direction. For example, the rear ends of plural keys (the white key11wand/or the black key11b) may be are supported by the key frame12through elastic deformation members so that the front ends of the plural keys can rock in vertical direction. Concretely, the rear ends of the plural keys are connected to a fixing member fixed to the key frame12through thin and elastic connection members, wherein the fixing member is extended in the lateral direction, the connection members are extended horizontally or vertically, and the plural keys, the connection members and the fixing member are formed integrally. In this case, for example, the connection members for the white keys11ware extended horizontally, and the connection members for the black keys11bare extended vertically.