Keyboard mechanism of a keyboard instrument

Abstract

To provide a keyboard device of a keyboard instrument, which enables a key support mechanism having a first arm and a second arm to be easily incorporated into a keyboard chassis during assembly and enables efficient assembly.SOLUTION: The keyboard device of the keyboard instrument includes: a keyboard chassis 4 having a first support shaft 18a and a second support shaft 19a as well as a flat plate part 12a provided to extend laterally between them; keys 2 arranged in an upper part of the keyboard chassis; and a key support mechanism 6 provided to engage with the keyboard chassis 4 and to support the keys 2 from below. The flat plate part 12a has relief parts 12c, 12d for avoiding interference with a first arm 31 of the key support mechanism 6 during assembly.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a keyboard device of a keyboard instrument, such as an electronic piano, which is applied to a keyboard instrument and includes a rotating member that rotates as a key is pressed.

Background Art

[0002] Conventionally, as a keyboard device of this type of keyboard instrument, for example, the one described in Patent Document 1 already filed by the applicant is known. This keyboard device includes a keyboard chassis formed of a resin molded product having a predetermined shape, a plurality of keys including white keys and black keys rotatably supported on the upper part of the keyboard chassis, and a plurality of hammers rotatably attached to the keyboard chassis for each key. In this keyboard device, the front end of the hammer is pushed down by an actuator portion protruding downward from the front portion of the key when the key is pressed, and the hammer is rotated.

[0003] In addition, a substantially horizontal flat plate portion is provided between the keys and the hammers on the keyboard chassis of the keyboard device, and a key guide for guiding the rotating black key in the vertical direction and preventing lateral sway is erected on this flat plate portion. Below the front end of the flat plate portion, a support shaft for rotatably supporting the hammer is provided. Therefore, when assembling the keyboard device, the hammer is inserted into the inside of the keyboard chassis through the opening on the front side of the flat plate portion and engaged with the support shaft, whereby the hammer is attached to the keyboard chassis.

[0004] In recent years, in addition to the above-described hammers, a keyboard device has been developed that includes an arm that connects a key and a hammer and is rotatably supported by a keyboard chassis. In such a keyboard device, the key is supported from below by a key support mechanism having the above-described hammer and arm (hereinafter, referred to as "first arm" and "second arm" respectively in this column), and the pressed key rotates around a virtual fulcrum located behind the rear end of the key.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2012-189872 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, when assembling the key support mechanism having the first and second arms described above into the aforementioned keyboard chassis, the assembly process can become complicated. Specifically, for example, when connecting the first arm to the second arm after rotatably mounting the second arm to the keyboard chassis, the connection point between the two arms is located below the flat plate portion of the keyboard chassis, making it difficult to see the connection point from the outside. Moreover, the presence of the flat plate portion in the keyboard chassis restricts the range of motion of the first arm when connecting the two arms, which can make the connection with the second arm more difficult.

[0007] The present invention was made to solve the above-mentioned problems, and aims to provide a keyboard device for a keyboard instrument in which a key support mechanism having a first arm and a second arm can be easily assembled to the keyboard chassis during assembly, thereby enabling efficient assembly. [Means for solving the problem]

[0008] To achieve the above objective, the invention according to claim 1 comprises a keyboard chassis having a first support shaft extending in the left-right direction, a second support shaft positioned at a predetermined distance behind and above the first support shaft and extending in the left-right direction, and a flat plate portion provided between the first and second support shafts so as to extend in the left-right direction; a key extending a predetermined length in the front-rear direction and positioned on the upper part of the keyboard chassis; and a key support mechanism provided to engage with the keyboard chassis and support the key from below, wherein the key support mechanism is configured to extend a predetermined length in the front-rear direction, and includes a first arm that is rotatably and detachably engaged with the first support shaft and whose front end is rotatably connected to the front of the key, and extends a predetermined length in the front-rear direction The keyboard chassis is configured such that it has a second arm which is rotatably and detachably engaged with the second support shaft, and whose rear end is rotatably connected to the rear of the key, and whose front connecting portion of the second arm, which is in front of the second support shaft, is rotatably and detachably connected to the rear connecting portion of the first arm, which is in rear of the first support shaft of the first arm, and the flat plate portion of the keyboard chassis is characterized in that, when the first arm and the second arm are attached to the keyboard chassis during assembly, the rear connecting portion of the first arm of the first arm is connected to the front connecting portion of the second arm of the second arm, which is held below the front end of the flat plate portion, while the second arm remains engaged with the second support shaft, thereby avoiding interference with the first arm.

[0009] In this configuration, the first and second arms of the key support mechanism are rotatably supported on the first and second support shafts of the keyboard chassis, respectively, and the keys, which extend in the front-to-back direction, are supported from below by both arms. In addition, a flat plate portion is provided on the keyboard chassis between the first and second support shafts, extending in the left-to-right direction.

[0010] When assembling the keyboard mechanism, when attaching the first and second arms to the keyboard chassis, the second arm is first attached to the second support shaft, and while maintaining this position, the second arm is rotated to position the front connecting portion of the second arm below the front end of the flat plate. Then, the first arm is inserted between the first support shaft and the flat plate, and the rear connecting portion of the first arm is connected to the front connecting portion of the second arm. In this case, since the flat plate is provided with a relief portion to avoid interference with the first arm, the first arm can be moved relatively far, and the first arm can be connected to the second arm while the relief portion functions as a guide. As a result, the key support mechanism having the first and second arms can be easily assembled to the keyboard chassis, and assembly can be performed efficiently.

[0011] The invention according to claim 2 is a keyboard device for a keyboard instrument as described in claim 1, characterized in that the relief portion penetrates vertically and opens forward, and its planar shape is formed in a U-shape.

[0012] With this configuration, when assembling the key support mechanism corresponding to the key to the keyboard chassis, a U-shaped relief section is provided in the planar shape, so that the first arm can be easily connected to the second arm while avoiding interference between the first arm and the flat plate section during the assembly of the keyboard device.

[0013] The invention according to claim 3 is a keyboard device for a keyboard instrument as described in claim 1, characterized in that a key guide for guiding the key is erected on the flat plate portion, and the relief portion is provided below the key guide and is formed in the shape of a recessed groove that opens from the front downwards.

[0014] With this configuration, the key guide is erected on the flat plate, and when assembling the key support mechanism corresponding to the key to the keyboard chassis, a recessed groove-shaped relief section that opens from front to rear is provided on the underside of the key guide. This allows the first arm to be easily connected to the second arm while avoiding interference between the first arm and the flat plate during the assembly of the keyboard device. [Brief explanation of the drawing]

[0015] [Figure 1] This is a perspective view showing a part (one octave) of the keyboard mechanism of an electronic piano to which the present invention is applied, where (a) shows the external appearance of the keyboard mechanism, and (b) shows the state with all keys except the white and black keys on the far left omitted. [Figure 2] Figure 1(b) is a perspective view showing the keyboard device with the white keys and black keys removed from the keyboard chassis, along with their respective key support mechanisms. [Figure 3] (a) is a plan view of the keyboard assembly with all keys except the leftmost white and black keys omitted, and (b) is a cross-sectional view along line AA. [Figure 4] This is a perspective view showing the white keys and key support mechanism; (a) shows the white keys and key support mechanism connected, and (b) shows the white keys and key support mechanism disassembled. [Figure 5] This is a perspective view showing the black keys and key support mechanism; (a) shows the black keys and key support mechanism connected, and (b) shows the black keys and key support mechanism disassembled. [Figure 6] This diagram illustrates the operation of the white keys in a keyboard mechanism, with (a) showing the released state and (b) showing the pressed state. [Figure 7] This diagram illustrates the operation of the black keys in a keyboard mechanism, with (a) showing the released state and (b) showing the pressed state. [Figure 8] This diagram shows the keyboard chassis, with (a) being an external perspective view and (b) being a plan view. [Figure 9] This is an explanatory diagram illustrating the sequential attachment of the first and second arms to the keyboard chassis during the assembly of the keyboard unit. [Figure 10] This is an explanatory diagram following Figure 9. [Modes for carrying out the invention]

[0016] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1(a) shows only one octave of the keyboard device 1 of an electronic piano to which the present invention is applied. In the following description, first, the basic configuration and operation of the keyboard device 1 will be described, and then the main part of the present invention will be described.

[0017] FIG. 1(b) shows a state in which keys 2 other than the leftmost white key 2a and black key 2b are omitted in the keyboard device 1 of FIG. 1(a), and FIG. 2 shows a state in which the white keys 2a and black keys 2b are removed from the keyboard chassis 4 together with the key support mechanism 6.

[0018] This keyboard device 1 includes a keyboard chassis 4, a plurality of keys 2 composed of white keys 2a and black keys 2b arranged side by side in the left-right direction, a key support mechanism 6 that is rotatably attached to the keyboard chassis 4 for each key 2 and supports the corresponding key 2 from below, a key switch 3 for detecting key depression information of each key 2, and the like.

[0019] The keyboard chassis 4 includes a chassis body 4a made of a resin molded product having a predetermined shape by injection molding a predetermined resin material (for example, ABS resin). As shown in FIG. 3, in this chassis body 4a, its front part 11, middle part 12, and rear part 13 are all formed so as to extend in the left-right direction (the left-right direction in FIG. 3(a)) as a whole, and these are integrally molded by a plurality of ribs 14 spaced apart in the left-right direction and each extending in the front-rear direction. In the following description, in the keyboard chassis 4, the front part 11, middle part 12, and rear part 13 of the chassis body 4a will be referred to as the "chassis front part 11", "chassis middle part 12", and "chassis rear part 13", respectively.

[0020] The front part 11 of the chassis is primarily for guiding the white keys 2a when pressed and for regulating the upper and lower limits of their front ends. Multiple white key guides 11a are installed on the front part 11 of the chassis, arranged horizontally, and inserted from below for each white key 2a to prevent lateral movement of the white keys 2a. Furthermore, the front part 11 of the chassis is provided with engagement holes 11b, 11b that penetrate vertically on both the left and right sides of each white key guide 11a, and the two upper limit position regulating parts 21, 21 of the white key 2a, described later, engage with these engagement holes 11b, 11b, respectively, with the left and right sides penetrating through them. In addition, the front part 11 of the chassis is provided with a stopper mounting part 11c that protrudes forward and extends horizontally across the entire chassis body 4a, and a key upper limit stopper 16a and a key lower limit stopper 16b for the white keys are attached to the lower and upper surfaces of this stopper mounting part 11c, respectively, so as to extend horizontally. Furthermore, the front part 11 of the chassis is provided with a stopper mounting portion 11d for black keys that extends horizontally across the entire chassis body 4a at a predetermined position behind the white key guide 11a, and a key upper limit stopper 17 for black keys is attached to this stopper mounting portion 11d so as to extend horizontally.

[0021] The chassis intermediate section 12 primarily guides the black keys 2b when pressed and pivotably supports the first arm 31 and second arm 32 of the key support mechanisms 6a and 6b for the white and black keys, which will be described later. This chassis intermediate section 12 has a flat plate-shaped section 12a extending in the left-right direction, and a plurality of black key guides 12b erected on this flat section 12a and arranged at appropriate intervals in the left-right direction. Each black key guide 12b is inserted from below for each black key 2b, preventing the black key 2b from swinging laterally. In addition, a first arm support section 18 is provided at the front of the chassis intermediate section 12 to support the first arm 31 of the key support mechanism 6. This first arm support section 18 has a plurality of first support shafts 18a that are provided between adjacent ribs 14, 14 so as to extend in the left-right direction, and the first arm 31 is pivotably supported on these first support shafts 18a. Furthermore, a second arm support section 19 is provided at the rear of the chassis intermediate section 12 to support the second arm 32 of the key support mechanism 6. This second arm support section 19 has a plurality of second support shafts 19a that are provided between adjacent ribs 14, 14 and extend in the left-right direction. The plurality of second support shafts 19a are arranged on the same axis extending in the left-right direction, at a position rearward and higher than the first support shaft 18a, and the second arm 32 is pivotably supported on these second support shafts 19a. A first arm lower limit stopper 10b is provided at a predetermined position on the middle rail 8, which will be described later, located on the lower side of the chassis intermediate section 12, and extends in the left-right direction across the entire chassis body 4a.

[0022] Furthermore, the key switch 3 is mounted on the lower part of the keyboard chassis 4, between the front part 11 and the middle part 12 of the chassis. This key switch 3 consists of a horizontally elongated printed circuit board 3a extending in the left-right direction, and a plurality of switch bodies 3b, each consisting of a rubber switch mounted on this printed circuit board 3a for each key 2, which is pressed by the first arm 31 when the key is pressed.

[0023] The rear chassis portion 13 primarily serves to guide the key 2 vertically while preventing lateral movement at its rear end, and to regulate the upper limit position of the rear end of the first arm 31. As shown in Figures 2 and 3(a), the rear chassis portion 13 has multiple partition walls 13a spaced apart from each other in the left-right direction to separate adjacent keys 2, 2. Furthermore, as shown in Figure 3(b), a first arm upper limit stopper 10a is provided at a predetermined position on the upper part of the rear chassis portion 13, extending horizontally across the entire chassis body 4a. This first arm upper limit stopper 10a and the first arm lower limit stopper 10b provided in the middle portion 12 of the chassis are, respectively, for regulating the upper limit position when the first arm 31, which functions as a hammer for applying touch weight to the key 2, rotates upward, and the lower limit position when it rotates downward. Furthermore, a metal cover plate 15 is attached to the upper part of the rear section 13 of the chassis, extending horizontally across the entire chassis body 4a and positioned to cover the rear end of the key 2.

[0024] As shown in Figures 2 and 3(a), the chassis body 4a of the keyboard chassis 4 configured as described above is provided with a plurality of first openings 5a that open upward and forward, and a plurality of second openings 5b that open upward. Through each of the first openings 5a, the first arm 31 of the key support mechanism 6 is engaged with the first support shaft 18a from the outside, and through each of the second openings 5b, the second arm 32 is engaged with the second support shaft 19a from the outside.

[0025] Furthermore, in the keyboard chassis 4 described above, multiple chassis bodies 4a are connected to each other in a left-right direction, and are screwed to metal front rails 7, middle rails 8, and rear rails 9, which extend in the left-right direction and are arranged at predetermined intervals from each other in the front-back direction. The keyboard chassis 4 is then fixed to a shelf (not shown) of the electronic piano via the front rails 7 and rear rails 9.

[0026] Next, the key 2 and the key support mechanism 6 will be described. Figure 4(a) shows an enlarged view of the white key 2a and its key support mechanism 6a, and Figure 4(b) shows them in an exploded view. As shown in the figure, the white key 2a is formed by injection molding of a predetermined resin material (e.g., AS resin) to extend a predetermined length in the front-rear direction and to be hollow and open downwards. The front end of the white key 2a is provided with a pair of left and right upper limit position restricting parts 21, 21 that extend downwards from the left and right side walls and whose lower ends are bent forward. As described above, these upper limit position restricting parts 21, 21 engage with the left and right engagement holes 11b, 11b of the front part 11 of the chassis, respectively, by penetrating them.

[0027] Furthermore, a key front connecting portion 22 is provided at the front of the white key 2a at a predetermined position behind the upper limit position restricting portion 21, and is connected to the first arm 31 of the key support mechanism 6a. This key front connecting portion 22 has a connecting recess 22a that is formed in a U-shape with an elongated hole shape on its side and opens forward. A cushioning member 20 is also attached to this connecting recess 22a so as to cover its entire inner circumferential surface, in order to suppress the generation of noise when the connecting shaft 35b of the first arm 31 (described later) slides within the connecting recess 22a. A keyboard weight 30 (see Figure 3) is attached to the front of the white key 2a between the upper limit position restricting portion 21 and the key front connecting portion 22 to impart a desired touch weight when the key is pressed.

[0028] Furthermore, a rear key connecting portion 23 is provided at the rear of the white key 2a, which is connected to the second arm 32 of the key support mechanism 6a. This rear key connecting portion 23 hangs downward from the center of the white key 2a in the left-right direction and has a plate-shaped connecting body portion 23a having a predetermined thickness in the left-right direction, and a pair of left and right engaging protrusions 23b, 23b that protrude coaxially from the left and right sides of the connecting body portion 23a, respectively. In addition, a tool insertion hole 24 is formed at the rear of the white key 2a, which penetrates in the vertical direction, and is used to insert a predetermined tool from above when releasing the connection between the white key 2a and the second arm 32 of the key support mechanism 6a during maintenance of the keyboard device 1.

[0029] On the other hand, the key support mechanism 6a includes a first arm 31 and a second arm 32 that engage with each other and are connected to the front key connecting portion 22 and the rear key connecting portion 23 of the white key 2a, respectively.

[0030] As shown in Figure 4(b), the first arm 31 is composed of an arm body 33 and two weights 34, 34 attached to the arm body 33. The arm body 33 is made of a resin molded product of a predetermined shape, such as by injection molding a predetermined resin material (e.g., polyacetal). The arm body 33 extends a predetermined length in the front-rear direction, and a first arm front connecting portion 35 is provided at its front end, which connects to the key front connecting portion 22 of the white key 2a. The first arm front connecting portion 35 has a box-shaped box portion 35a that opens upward and forward, and a connecting shaft 35b that extends in the left-right direction, connecting the front upper ends of the left and right side walls of the box portion 35a. The connecting shaft 35b is rotatably and slidably connected in the front-rear direction to the connecting recess 22a of the key front connecting portion 22 of the white key 2a.

[0031] Furthermore, the arm body 33 has a U-shaped bearing portion 36 with a side shape that opens downward at a predetermined position immediately behind the first arm front connecting portion 35, and this bearing portion 36 rotatably engages with the first support shaft 18a of the keyboard chassis 4. In addition, the arm body 33 is provided with a first arm rear connecting portion 37 that connects to the second arm 32 at a predetermined position behind the bearing portion 36. Specifically, the first arm rear connecting portion 37 has a connecting shaft 37a that extends in the left-right direction, with both ends protruding outward from the left and right sides of the arm body 33. Both ends of this connecting shaft 37a engage with the connecting recesses 45b, 45b of the second arm front connecting portion 45 of the second arm 32, which will be described later.

[0032] Two elongated, plate-shaped weights 34, 34 are attached to the weight attachment section 38 at the rear of the arm body 33, sandwiching the weight attachment section 38 from both sides. Each weight 34 is made of a material with a higher specific gravity than the arm body 33 (for example, a metal such as iron), and is formed into a predetermined shape by pressing a metal plate.

[0033] The second arm 32 is made of a resin molded product of a predetermined shape by injection molding the same resin material as the arm body 33 of the first arm 31. This second arm 32 is shorter than the first arm 31 and extends for a predetermined length in the front-rear direction. The second arm 32 also has a C-shaped bearing portion 41 near the center in the longitudinal direction, with its side shape opening forward, and this bearing portion 41 rotatably engages with the second support shaft 19a of the keyboard chassis 4.

[0034] Furthermore, the rear end of the second arm 32 is provided with a second arm rear connecting portion 42 that connects to the key rear connecting portion 23 of the white key 2a. This second arm rear connecting portion 42 is formed in a bifurcated shape and has two left and right connecting arm portions 43, 43 that extend parallel to each other for a predetermined length along the length direction of the second arm 32. A connecting hole 43a that penetrates in the left-right direction is formed at the rear end of each connecting arm portion 43. The two connecting arm portions 43, 43 sandwich the connecting body portion 23a of the key rear connecting portion 23 of the white key 2a from both sides between their rear ends, and each connecting hole 43a is rotatably fitted into the corresponding engaging projection 23b of the key rear connecting portion 23.

[0035] Furthermore, the front of the second arm 32 is provided with a second arm front connecting portion 45 that connects to the first arm rear connecting portion 37 of the first arm 31. This second arm front connecting portion 45 has a pair of left and right connecting pieces 45a, 45a separated from each other at a predetermined distance in the left-right direction, and each connecting piece 45a has a U-shaped connecting recess 45b formed therein that has an elongated hole shape on its side and opens forward. The left and right connecting pieces 45a, 45a of the second arm front connecting portion 45 are rotatably and slidably engaged with both ends of the connecting shaft 37a of the first arm 31 via their connecting recesses 45b, 45b.

[0036] Figure 5(a) shows an enlarged view of the black key 2b and its key support mechanism 6b, while Figure 5(b) shows them in an exploded view. The black key 2b is formed by injection molding of the same resin material as the white key 2a, making it shorter than the white key 2a, extending a predetermined length in the front-to-back direction, and forming a hollow shape that opens downwards. The front lower end of the black key 2b is provided with a key front connecting portion 26, which is formed in substantially the same way as the key front connecting portion 22 of the white key 2a. This key front connecting portion 26 has a connecting recess 26a that is formed in a U-shape with an elongated hole shape on its side and opens forwards. Furthermore, the key front connecting portion 26 has an extension portion 26b at the lower front end of the connecting recess 26a that extends a predetermined length forward from the front surface of the black key 2b body, and this extension portion 26b functions as an upper limit position regulating portion for the black key 2b. In the following explanation, the same reference numerals will be used for the black keys 2b and key support mechanism 6b as for the white keys 2a and key support mechanism 6a described above, and detailed explanations will be omitted.

[0037] The key support mechanism 6b that supports the black key 2b is configured in almost the same way as the key support mechanism 6a for the white keys described above. Specifically, the arm body 33 of the first arm 31 and the second arm 32 of the key support mechanism 6b are configured to be exactly the same shape and size as the arm body 33 and the second arm 32 of the key support mechanism 6a for the white keys. The two weights 34, 34 on the left and right of the key support mechanism 6b for the black keys are shown to be the same as the weights 34, 34 of the key support mechanism 6b for the white keys, but their shape and length are appropriately changed according to the touch weight required for the key 2.

[0038] Next, the operation of the keys 2 and key support mechanisms 6 in the keyboard device 1 configured as described above will be explained. Figure 6 shows the operation of the white keys 2a and their key support mechanisms 6a, and Figure 7 shows the operation of the black keys 2b and their key support mechanisms 6b.

[0039] In the unlocked state shown in Figure 6(a), when the front end of the white key 2a is pressed down by the player's finger, the front key connecting portion 22 of the white key 2a moves downward, causing the first arm 31 to rotate counterclockwise around the first pivot shaft 18a. As the first arm 31 rotates, the front second arm connecting portion 45, which engages with the connecting shaft 37a of the first arm 31 via the connecting recess 45b, moves upward. As a result, the second arm 32 rotates clockwise around the second pivot shaft 19a. With this rotation of the second arm 32, the rear key connecting portion 23, which is connected via the rear second arm connecting portion 42 at its rear end, is pulled down, causing the rear end of the white key 2a to move downward.

[0040] Furthermore, when the first arm 31 rotates as described above, the box portion 35a of the front connecting portion 35 of the first arm moves downward, and the bottom wall of the box portion 35a presses from above against the switch body 3b of the key switch 3 corresponding to the pressed key 2. As a result, the electronic piano detects the key press information of the pressed key 2, and based on the detected key press information, sound is generated from a speaker (not shown).

[0041] As described above, when the white key 2a is pressed down, the weight 34 of the first arm 31 tilts upward and backward as the first arm 31 rotates counterclockwise, as shown in Figure 6(b), and its rear end contacts the first arm upper limit stopper 10a from below. This prevents the first arm 31 from rotating any further. When the front end of the white key 2a is pressed down to its lowest position, the front end of the white key 2a contacts the key lower limit stopper 16b, preventing the white key 2a from being pressed any further down.

[0042] As described above, the pressed white key 2a operates to rotate around a virtual pivot point P located behind its rear end. The position of this virtual pivot point P is set such that, for example, the distance from the front end of the white key 2a is approximately twice the length of the white key 2a itself. As a result, when the front end of the white key 2a is pushed down to its lowest position, the front end of the white key 2a is located lower by a predetermined key stroke (e.g., 10 mm) and the rear end is located lower by a distance of approximately half the key stroke (e.g., 5 mm) compared to the released state shown in Figure 6(a).

[0043] On the other hand, when the finger is released from the pressed-down white key 2a, the weight of the weight 34 causes the first arm 31 of the key support mechanism 6a to rotate in the opposite direction, and consequently, the second arm 32 also rotates in the opposite direction. As a result, the white key 2a rotates upward around the virtual pivot point P. Then, a predetermined portion of the first pivot shaft 18a on the first arm 31 comes into contact with the first arm lower limit stopper 10b from above, and both upper limit position restricting parts 21, 21 of the white key 2a come into contact with the key upper limit stopper 16a from below, preventing further rotation of the white key 2a and returning it to its original released state.

[0044] Furthermore, the operation of the black key 2b when pressed is the same as that of the white key 2a and the key support mechanism 6a described above. That is, in the released state shown in Figure 7(a), when the front end of the black key 2b is pressed down, the first arm 31 rotates counterclockwise around the first pivot shaft 18a, and the second arm 32 rotates clockwise around the second pivot shaft 19a, causing the black key 2b to rotate around a virtual pivot point Q at the rear. The position of this virtual pivot point Q is set, for example, so that the distance from the front end of the black key 2b is approximately twice the length of the black key itself, similar to the virtual pivot point P of the white key 2a described above. Therefore, when the front end of the black key 2b is pressed down to its lowest position, the front end of the black key 2b is located lower by a predetermined key stroke, and the rear end is located lower by a distance of approximately half the key stroke, compared to the released state shown in Figure 7(a).

[0045] On the other hand, when the finger is released from the pressed-down black key 2b, the first arm 31 and the second arm 32 of the key support mechanism 6b rotate in the opposite direction, and consequently, the black key 2b rotates upward around the virtual pivot point Q. Then, the extended portion 26b of the key front connecting portion 26 of the black key 2b comes into contact with the key upper limit stopper 17 from below, preventing further rotation of the black key 2b and returning it to its original unlocked state.

[0046] Next, the main parts of the present invention will be described with reference to Figures 8 to 10. The main part of the present invention is to configure the keyboard chassis 4 so that the key support mechanism 6 having the first arm 31 and the second arm 32 can be easily assembled when assembling the keyboard device 1.

[0047] Figure 8 shows the keyboard chassis 4, where (a) is an external perspective view and (b) is a plan view. As shown in this figure and in Figure 3(b) above, the keyboard chassis 4 has a flat section 12a (flat plate section) extending in the left-right direction between the first support shaft 18a, which rotatably supports the first arm 31, and the second support shaft 19a, which rotatably supports the second arm 32. A plurality of (five in Figure 8) black key guides 12b are erected on this flat section 12a.

[0048] The flat portion 12a described above has multiple relief sections 12c and 12d formed therein, corresponding to each key support mechanism 6, to prevent interference between the first arm 31 and the flat portion 12a when assembling the keyboard device 1 and attaching the key support mechanism 6 to the keyboard chassis 4.

[0049] Specifically, the relief section corresponding to the key support mechanism 6a for the white keys (hereinafter referred to as the "white key relief section 12c" as appropriate) penetrates vertically and opens forward, and its planar shape is formed in a U-shape. As shown in Figure 8, in this keyboard chassis 4, seven white key relief sections 12c are formed in the flat section 12a along the left-right direction.

[0050] On the other hand, the relief section corresponding to the key support mechanism 6b for the black keys (hereinafter referred to as the "black key relief section 12d") is provided on the lower side of the black key guide 12b and is formed in the shape of a recessed groove that opens from the front downwards. As shown in Figure 8, in this keyboard chassis 4, five black key relief sections 12d are formed in the flat section 12a along the left-right direction.

[0051] The aforementioned relief sections 12c for each white key and 12d for each black key are formed during the molding of the chassis body 4a.

[0052] Here, with reference to Figures 9 and 10, the method for attaching the first arm 31 and the second arm 32 of the key support mechanism 6a for the white keys to the keyboard chassis 4 during the assembly of the keyboard device 1 will be explained.

[0053] As shown in Figure 9(a), first, the second arm 32 is inserted from above into the second opening 5b of the keyboard chassis 4 in a position slightly tilted backward relative to the vertical. In this case, the opening of the bearing portion 41 of the second arm 32 is aligned with the second support shaft 19a of the keyboard chassis 4, and the second support shaft 19a is inserted into the bearing portion 41. As a result, as shown in Figure 9(b), the second arm 32 is attached to the second support shaft 19a in a rotatable state.

[0054] Next, as shown in Figure 9(c), the second arm 32 is rotated clockwise around the second support shaft 19a to hold it in a nearly horizontal position. In this case, the connecting recess 45b of the front connecting portion 45 of the second arm is located below the front end of the flat portion 12a and is slightly angled upward relative to the horizontal.

[0055] Next, as shown in Figure 10(a), the first arm 31 is inserted from the front into the first opening 5a of the keyboard chassis 4 with the arm tilted slightly downward and backward relative to the horizontal. Then, while pushing the first arm 31 backward, the connecting shaft 37a of the first arm 31 is inserted from the front into the connecting recess 45b of the second arm 32, as shown in Figure 10(b). In this case, as shown in Figure 10(b), the diagonally upper portion of the connecting shaft 37a of the first arm 31 fits into the white key relief portion 12c. This prevents the first arm 31 from interfering with the front end of the flat portion 12a, and allows the connecting portion 37a of the first arm 31 to be easily inserted into the connecting recess 45b of the second arm 32, with the white key relief portion 12c acting as a guide. In this way, the first arm 31 is rotatably and slidably connected to the second arm 32 via the connecting shaft 37a.

[0056] Then, while maintaining the connection between the first arm 31 and the second arm 32, the front part of the first arm 31 is moved downward, as shown in Figure 10(c), and the first support shaft 18a of the keyboard chassis 4 is inserted into the bearing portion 36 of the first arm 31. As a result, the first arm 31 is attached to the first support shaft 18a in a rotatable state. With this, the attachment of the first arm 31 and the second arm 32 to the keyboard chassis 4 is completed.

[0057] On the other hand, the method of attaching the first arm 31 and the second arm 32 of the black key support mechanism 6b to the keyboard chassis 4 is almost the same as that of the white key support mechanism 6a described above, so the explanation will be omitted. The only difference in the attachment of the first arm 31 and the second arm 32 of the black key support mechanism 6b to the keyboard chassis 4 is that, as shown in Figure 10(b) above, when the connecting shaft 37a of the first arm 31 is connected to the connecting recess 45b of the second arm 32, the diagonally upper portion of the connecting shaft 37a of the first arm 31 is inserted into the black key relief portion 12d.

[0058] As described in detail above, according to this embodiment, the flat portion 12a of the keyboard chassis 4 is provided with a white key relief portion 12c and a black key relief portion 12d, corresponding to the white key and black key support mechanisms 6a and 6b, respectively. This allows the first arm 31 to move relatively far, and the first arm 31 can be connected to the second arm 32 while both relief portions 12c and 12d function as guides. As a result, the key support mechanism 6 having the first arm 31 and the second arm 32 can be easily assembled to the keyboard chassis 4, and assembly can be carried out efficiently.

[0059] It should be noted that the present invention is not limited to the embodiments described above and can be implemented in various forms. Furthermore, the detailed configurations of the white key relief portion 12c and the black key relief portion 12d shown in the embodiments are merely illustrative and can be modified as appropriate within the scope of the spirit of the present invention. [Explanation of symbols]

[0060] 1 Keyboard device 2 keys 2a white key 2b black key 4-key chassis 5a 1st opening 5b 2nd opening 6 Key support mechanism 6a Key support mechanism for white keys 6b Key support mechanism for black keys 12a Flat area 12b Black Key Guide (Key Guide) 12c White key relief section (relief section) 12d Black key escape section (escape section) 18. First arm support section 18a 1st spindle 19. Second arm support section 19a 2nd spindle 31. First Arm 32. Second Arm 36 Bearing section 37. Rear connection section of the first arm 37a Connecting shaft 45 Front connecting section of the second arm 45b Connecting recess P (White Key) Virtual pivot point Q: Virtual pivot point of the black key

Claims

1. A keyboard chassis having a first support shaft extending in the left-right direction, a second support shaft positioned a predetermined distance behind and above the first support shaft and extending in the left-right direction, and a flat plate portion provided between the first and second support shafts so as to extend in the left-right direction, A key extending a predetermined length in the front-to-back direction and positioned on the upper part of the keyboard chassis, A key support mechanism is provided to engage with the keyboard chassis and to support the key from below, Equipped with, The aforementioned key support mechanism is A first arm is configured to extend a predetermined length in the front-rear direction, is rotatably and detachably engaged with the first support shaft, and its front end is rotatably connected to the front of the key, A second arm is configured to extend a predetermined length in the front-rear direction, and is rotatably and detachably engaged with the second support shaft, with its rear end rotatably connected to the rear of the key, and the front connecting portion of the second arm, which is forward of the second support shaft, being rotatably and detachably connected to the rear connecting portion of the first arm, which is backward of the first support shaft. It has, The keyboard device for a keyboard instrument is characterized in that the flat plate portion of the keyboard chassis has a relief portion to avoid interference with the first arm when the second arm is attached to the keyboard chassis during assembly, while the second arm is engaged with the second support shaft, and the rear connecting portion of the first arm is connected to the front connecting portion of the second arm which is held below the front end of the flat plate portion.

2. The keyboard device for a keyboard instrument according to claim 1, characterized in that the relief portion penetrates vertically and opens forward, and its planar shape is formed in a U-shape.

3. A key guide for guiding the key is erected on the flat plate portion. The keyboard device for a keyboard instrument according to claim 1, characterized in that the relief portion is provided below the key guide and is formed in the shape of a recessed groove that opens from the front downwards.

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