Keyboard device for keyboard instruments

Abstract

To provide a keyboard device of a keyboard instrument, in which assemblability during manufacturing can be improved and resolvability during maintenance can be improved with respect to a key support mechanism assembled to a keyboard chassis.SOLUTION: A keyboard device of a keyboard instrument includes: a keyboard chassis 4; keys 2 arranged above the chassis; and a key support mechanism 6 for supporting the keys 2 from below, operating the pressed keys 2 to rotate with virtual fulcrums P and Q as centers when the keys are pressed. A first arm 31 and a second arm 32 of the key support mechanism 6 are configured to be attached to the keyboard chassis 4 while one of the firs arm 31 and the second arm 32 remains rotatably engaged with the keyboard chassis 4, and the other of the first arm 31 and the second arm 32 is connected to the other during attachment to the keyboard chassis 4 at assembly.SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] The present invention relates to a keyboard device for a keyboard instrument such as an electronic piano, in which a depressed key rotates around a virtual fulcrum located behind its rear end. [Background technology]

[0002] A known example of this type of keyboard device is disclosed in Patent Document 1, which was previously filed by the same applicant. This keyboard device includes a horizontal, plate-shaped base, a plurality of keys mounted above the base and extending a predetermined length in the front-to-rear direction, and a plurality of link mechanisms mounted on the base and supporting each key from below. The link mechanisms include a front connecting link bar extending a predetermined length in the front-to-rear direction and having its front end rotatably connected to the front end of the key, and a rear connecting link bar extending a predetermined length in the front-to-rear direction and having its rear end rotatably and slidably connected to the rear end of the key. The front connecting link bar and the rear connecting link bar are rotatably supported near the center of their respective lengths and are rotatably and slidably connected to each other. Both the front connecting link bar and the rear connecting link bar are made of elongated metal plates and formed into a predetermined shape.

[0003] In a keyboard device configured as described above, when the front end of a key is pressed down, the front connecting link bar and the rear connecting link bar each rotate in a predetermined direction, and when the front end of the key is pressed down to its lowest position, the front end is positioned a predetermined distance (e.g., 10 mm) lower than when the key is released, and the rear end moves downward a distance that is approximately half of the predetermined distance (e.g., 5 mm). In other words, in this keyboard device, when a key is pressed, the key rotates around a virtual fulcrum, as if there was a fulcrum (virtual fulcrum) at a predetermined position behind the rear end of the key. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-52391 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-mentioned keyboard device, the front and rear connecting link bars of the link mechanism that supports the keys are both made of metal plates. Therefore, to rotatably support the front and rear connecting link bars, support pins extending in the left-right direction are inserted into the corresponding connecting link bars at the upper ends of support parts erected on the base and fixed to the support parts. Furthermore, to rotatably and slidably connect the front and rear connecting link bars to each other, a long hole is formed in the front connecting link bar, and a connecting pin protruding in the left-right direction is provided in the rear connecting link bar, and this connecting pin is inserted into the long hole.

[0006] The link mechanism configured as described above is complicated to assemble during the manufacture of the keyboard device, and is not easily disassembled for maintenance. Therefore, there is room for improvement in the keyboard device.

[0007] The present invention has been made to solve the above-mentioned problems, and aims to provide a keyboard device for a keyboard instrument that can improve the assembly efficiency of the key support mechanism attached to the keyboard chassis during manufacturing, etc., and can also improve the disassembly efficiency during maintenance. [Means for solving the problem]

[0008] In order to achieve the above object, the invention according to claim 1 comprises a keyboard chassis, a key extending a predetermined length in the front-rear direction and arranged on the upper part of the keyboard chassis, and a key support mechanism that engages with the keyboard chassis and is provided to support the key from below, and that, when a key is pressed, causes the pressed key to rotate about an imaginary fulcrum located behind the rear end of the key, the key support mechanism being configured to extend a predetermined length in the front-rear direction, and including a first arm that rotatably and detachably engages with a first spindle provided on the keyboard chassis and whose front end is rotatably and slidably connected to the front part of the key, and and a second arm that rotatably and detachably engages with a second support shaft provided on the chassis behind the first support shaft, and whose rear end is rotatably connected to the rear of the key, and whose front connecting portion of the second arm forward of the second support shaft is rotatably, slidably and detachably connected to a rear connecting portion of the first arm behind the first support shaft of the first arm, and is characterized in that when attaching the first arm and second arm to the keyboard chassis during assembly, one of the first arm and second arm can be attached to the keyboard chassis while remaining rotatably engaged with the keyboard chassis, and the other of the first arm and second arm is connected to the other.

[0009] According to this configuration, a key extending a predetermined length in the front-to-rear direction and positioned at the top of the keyboard chassis is supported from below by a key support mechanism having a first arm and a second arm that rotatably engage with the keyboard chassis, and when pressed, rotates around an imaginary fulcrum located behind the rear end of the key. In the key support mechanism, the first arm rear connector of the first arm and the second arm front connector of the second arm are rotatably and slidably connected. Furthermore, the first arm and the second arm detachably engage with the keyboard chassis and are detachably connected to each other.

[0010] The first and second arms configured as described above are attached to the keyboard chassis during assembly as follows: First, one of the first and second arms is rotatably engaged with the keyboard chassis. Next, the other of the first and second arms is attached to the keyboard chassis while connected to one of them. In this case, the arm attached to the keyboard chassis first is rotated as needed, and the arm to be attached to the keyboard chassis later is connected to the arm attached first and attached to the keyboard chassis.

[0011] In this way, the first arm and the second arm can be attached to the keyboard chassis relatively easily, which improves the ease of assembly of the key support mechanism having the first arm and the second arm during manufacturing, etc. Furthermore, the first arm and the second arm can be removed from the keyboard chassis by reversing the procedure described above, which improves the ease of disassembling the key support mechanism during maintenance.

[0012] The invention of claim 2 is characterized in that, in the keyboard device of the keyboard instrument described in claim 1, the front connecting portion of the second arm has a first protrusion and a second protrusion that are spaced a predetermined distance from each other and protrude a predetermined length forward of the second arm, is open to the front of the second arm, and has a U-shaped side shape, and one front end of the first protrusion and the second protrusion is formed so as to protrude further forward than the other front end of the first protrusion and the second protrusion.

[0013] According to this configuration, the second arm front coupling portion of the second arm coupled to the first arm has the above-mentioned first protruding portion and second protruding portion, and these protruding portions open to the front of the second arm and form a U-shaped side surface. Therefore, when coupling the first arm and the second arm, the first arm and the second arm are coupled by inserting the first arm rear coupling portion of the first arm into the second arm front coupling portion of the second arm, i.e., from the front of the U-shape formed by the first protruding portion and the second protruding portion.

[0014] Furthermore, the front end of one of the first and second protrusions of the second-arm front connector is formed to protrude further forward than the front end of the other of the first and second protrusions. As a result, when connecting the first and second arms as described above, the distal end or inner surface of the protrusion that protrudes further forward of the first and second protrusions can be brought into contact with the first-arm rear connector while the connecting operation is performed, and the protrusion can be used as a guide. This facilitates the connection of the first and second arms.

[0015] The invention of claim 3 is characterized in that, in the keyboard device of a keyboard instrument described in claim 1 or 2, the second arm has a C-shaped side shape and a bearing portion that engages with the second support shaft by snap-fitting.

[0016] According to this configuration, the second arm has a C-shaped side surface and a bearing portion that rotatably engages with the second support shaft. This bearing portion engages with the second support shaft by snap-fitting. Therefore, when attaching or detaching the second arm to or from the second support shaft, applying a certain amount of force to the second arm can elastically deform the open portion of the bearing portion, allowing the second arm to be easily attached to or detached from the second support shaft.

[0017] The invention of claim 4 is characterized in that, in the keyboard device of the keyboard instrument described in claim 3, the second arm is provided with a tool engagement portion with which a specified tool engages when removing it from the keyboard chassis during maintenance.

[0018] According to this configuration, when removing the second arm from the keyboard chassis during maintenance, the second arm, whose bearing portion is engaged with the second support shaft by snap-fit, can be easily removed from the keyboard chassis by engaging a specified tool with the tool engagement portion and operating the tool in a specified direction. [Brief explanation of the drawings]

[0019] [Figure 1] 1A and 1B are perspective views showing a part (for one octave) of a keyboard device of an electronic piano to which the present invention is applied, in which (a) shows the appearance of the keyboard device, and (b) shows a state in which keys other than the white and black keys on the left end are omitted. [Figure 2] 1(b) is a perspective view showing the keyboard device shown in FIG. 1(b) with the white keys and black keys, together with their respective key support mechanisms, removed from the keyboard chassis. FIG. [Figure 3] 1(b) is a cross-sectional view taken along line AA of the keyboard device shown in FIG. 1(b). [Figure 4] 1A and 1B are perspective views showing a white key and a key support mechanism, in which FIG. 1A shows the white key and the key support mechanism connected together, and FIG. 1B shows the white key and the key support mechanism disassembled. [Figure 5] 1A and 1B are perspective views showing the black key and the key support mechanism, in which FIG. 1A shows the black key and the key support mechanism connected together, and FIG. 1B shows the black key and the key support mechanism disassembled. [Figure 6] 1A and 1B are diagrams for explaining the operation of a white key in a keyboard device, in which FIG. 1A shows a key-released state and FIG. 1B shows a key-depressed state. [Figure 7] 1A and 1B are diagrams for explaining the operation of black keys in a keyboard device, in which (a) shows the key-released state and (b) shows the key-depressed state. [Figure 8] FIG. 4 is an enlarged side view of the second arm. [Figure 9] FIG. 2(a) is a side view showing the state in which the first arm and the second arm are attached to the keyboard chassis, and FIG. 2(b) is an enlarged view showing the second support shaft on which the second arm is supported and its surroundings. [Figure 10] 5A and 5B are enlarged views for explaining the shapes and sizes of the second support shaft and the bearing portion of the second arm, where (a) shows the second support shaft and (b) shows the bearing portion of the second arm. [Figure 11] 10A and 10B are explanatory diagrams for sequentially explaining the attachment of the first arm and the second arm to the keyboard chassis, showing the case where the second arm is attached to the tip of the first arm. [Figure 12] FIG. 12 is an explanatory diagram following FIG. [Figure 13]10A and 10B are explanatory diagrams for sequentially explaining the attachment of the first arm and the second arm to the keyboard chassis, showing the case where the first arm is attached to the tip of the second arm. [Figure 14] FIG. 10 is an enlarged side view of the second arm provided with a tool engagement portion used when removing the second arm from the keyboard chassis; [Figure 15] 10A to 10C are explanatory diagrams for sequentially explaining the removal of the second arm from the keyboard chassis. DETAILED DESCRIPTION OF THE INVENTION

[0020] A preferred embodiment of the present invention will be described in detail below with reference to the drawings. Figure 1(a) shows only one octave of a keyboard device 1 of an electronic piano to which the present invention is applied. In the following explanation, the basic configuration and operation of the keyboard device 1 will be explained first, and then the main parts of the present invention will be explained.

[0021] Figure 1(b) shows the keyboard device 1 of Figure 1(a) with all keys 2 omitted except for the white key 2a and black key 2b on the left end, and Figure 2 shows the white key 2a and black key 2b removed from the keyboard chassis 4 together with the key support mechanism 6.

[0022] This keyboard device 1 includes a keyboard chassis 4, a plurality of keys 2 consisting of white keys 2a and black keys 2b arranged in a row in the left-right direction, a key support mechanism 6 rotatably attached to the keyboard chassis 4 for each key 2 and supporting the corresponding key 2 from below, and a key switch 3 for detecting key depression information for each key 2.

[0023] The keyboard chassis 4 includes a chassis main body 4a made of a resin molded product of a predetermined shape, obtained by injection molding a predetermined resin material (e.g., ABS resin). As shown in Figure 3, the chassis main body 4a has a front portion 11, a middle portion 12, and a rear portion 13, all of which are formed to extend in the left-right direction (the left-right direction in Figure 3(a)) as a whole, and are integrally formed with a plurality of ribs 14 spaced apart in the left-right direction and each extending in the front-to-rear direction. In the following description, the front portion 11, middle portion 12, and rear portion 13 of the chassis main body 4a of the keyboard chassis 4 will be referred to as the "chassis front portion 11," the "chassis middle portion 12," and the "chassis rear portion 13," respectively.

[0024] The chassis front section 11 primarily guides the white keys 2a when they are pressed and regulates the upper and lower limit positions of their front ends. A plurality of white key guides 11a are arranged side-by-side in the left-right direction on the chassis front section 11. Each white key guide 11a is inserted from below into the corresponding white key 2a to prevent the white key 2a from swaying sideways. The chassis front section 11 also has engagement holes 11b, 11b penetrating vertically on both the left and right sides of each white key guide 11a. Two upper limit position regulation sections 21, 21 (described later) of the white key 2a penetrate the engagement holes 11b, 11b, respectively. Furthermore, the chassis front section 11 is provided with a stopper mounting section 11c at its front end, which protrudes forward and extends laterally across the entire chassis body 4a. An upper limit key stopper 16a and a lower limit key stopper 16b for the white keys are attached to the lower and upper surfaces of the stopper mounting section 11c, respectively, so as to extend laterally. In addition, a stopper mounting portion 11d for the black keys is provided at a predetermined position behind the white key guide 11a on the front part 11 of the chassis, extending in the left-right direction across the entire chassis body 4a, and an upper key limit stopper 17 for the black keys is attached to this stopper mounting portion 11d so as to extend in the left-right direction.

[0025] The chassis intermediate section 12 primarily guides the black keys 2b when pressed and swingably supports the first and second arms 31 and 32 (described later) of the key support mechanisms 6a, 6b for the white and black keys. The chassis intermediate section 12 includes a flat section 12a extending laterally and a plurality of black key guides 12b arranged vertically on the flat section 12a and spaced apart appropriately in the left-right direction. Each black key guide 12b is inserted into each black key 2b from below to prevent the key from swaying laterally. The front of the chassis intermediate section 12 includes a first arm support section 18 that supports the first arm 31 of the key support mechanism 6. The first arm support section 18 includes a plurality of first support shafts 18a extending laterally between adjacent ribs 14. The first arms 31 are swingably supported by these first support shafts 18a. Furthermore, a second arm support section 19 that supports a second arm 32 of the key support mechanism 6 is provided at the rear of the chassis intermediate section 12. 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 that extends in the left-right direction, at a position rearward and higher than the first support shaft 18a, and the second arm 32 is supported by these second support shafts 19a so that it can swing freely. Note that a first arm lower limit stopper 10b that extends in the left-right direction across the entire chassis main body 4a is provided at a predetermined position on a middle rail 8 (described later) that is provided below the chassis intermediate section 12.

[0026] The key switch 3 is attached to the bottom of the keyboard chassis 4, between the chassis front section 11 and the chassis middle section 12. The key switch 3 is composed of a horizontally elongated printed circuit board 3a extending in the left-right direction, and multiple switch bodies 3b made of rubber switches attached to the printed circuit board 3a for each key 2 and pressed by a first arm 31 when the key is pressed.

[0027] The chassis rear section 13 primarily guides the key 2 vertically at its rear end while preventing lateral movement, and regulates the upper limit position of the rear end of the first arm 31. As shown in FIGS. 2 and 3(a), the chassis rear section 13 has multiple partition walls 13a spaced at predetermined intervals in the left-right direction to separate adjacent keys 2. Also, as shown in FIG. 3(b), a first arm upper limit stopper 10a extending left-right across the entire chassis main body 4a is provided at a predetermined position on the upper part of the chassis rear section 13. This first arm upper limit stopper 10a and the first arm lower limit stopper 10b provided on the chassis intermediate section 12 regulate the upper limit position and the lower limit position, respectively, of the first arm 31, which functions as a hammer for applying a touch weight to the key 2, when the first arm 31 rotates upward and downward. Furthermore, a metal cover plate 15 is attached to the upper part of the chassis rear part 13, extending in the left-right direction across the entire chassis body 4a and arranged to cover the rear end of the key 2.

[0028] 2 and 3(a), the chassis main 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 also open upward. The first arm 31 of the key support mechanism 6 engages with the first support shaft 18a from the outside through each of the first openings 5a, and the second arm 32 engages with the second support shaft 19a from the outside through each of the second openings 5b.

[0029] In the keyboard chassis 4, multiple chassis bodies 4a are connected to one another in a line up in the left-right direction, and are placed on and screwed to metal front rails 7, middle rails 8, and rear rails 9 that extend left-right and are arranged at a predetermined distance from one another in the front-to-rear direction. The keyboard chassis 4 is then fixed to a shelf board (not shown) of the electronic piano via the front rails 7 and rear rails 9.

[0030] Next, the key 2 and the key support mechanism 6 will be described. FIG. 4(a) shows an enlarged view of the white key 2a and its key support mechanism 6a, while FIG. 4(b) shows them exploded. As shown in the figure, the white key 2a is formed by injection molding a specific resin material (e.g., AS resin) to extend a specific length in the front-to-rear direction and to have a hollow shape that opens downward. The front end of the white key 2a is provided with a pair of left and right upper limit position restrictors 21, 21 that extend downward from the left and right side walls and are formed so that their lower ends are bent forward. As described above, these upper limit position restrictors 21, 21 are engaged in a state in which they penetrate the left and right engagement holes 11b, 11b of the chassis front part 11, respectively.

[0031] Additionally, a front-key connecting portion 22 is provided at the front of the white key 2a, at a predetermined position rearward of the upper limit position restrictor 21, for connecting to the first arm 31 of the key support mechanism 6a. This front-key connecting portion 22 has a connecting recess 22a with an elongated hole-like side and a U-shaped opening toward the front. A buffer member 20 is attached to the connecting recess 22a, covering its entire inner circumferential surface, to suppress noise generated when a connecting shaft 35b (described later) of the first arm 31 slides within the connecting recess 22a.

[0032] Furthermore, a key rear connector 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 key rear connector 23 hangs down from the center of the white key 2a in the left-right direction and has a plate-like connector body 23a with 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 connector body 23a. In addition, a tool insertion hole 24 is formed at the rear of the white key 2a, penetrating vertically. This tool insertion hole 24 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, for example during maintenance of the keyboard device 1.

[0033] On the other hand, the key support mechanism 6a includes a first arm 31 and a second arm 32 that are engaged with each other and connected to the front-key connecting portion 22 and the rear-key connecting portion 23 of the white key 2a, respectively.

[0034] As shown in FIG. 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 a resin molded product of a predetermined shape, typically obtained by injection molding a predetermined resin material (e.g., polyacetal). The arm body 33 extends a predetermined length in the front-to-rear direction, and its front end is provided with a first-arm front connector 35 that connects to the front-side connector 22 of the white key 2a. The first-arm front connector 35 has a box-shaped box portion 35a that opens upward and forward, and a connecting shaft 35b that extends left and right and connects the front upper ends of the left and right side walls of the box portion 35a. The connecting shaft 35b is connected to the connecting recess 22a of the front-side connector 22 of the white key 2a so as to be rotatable and slidable in the front-to-rear direction.

[0035] The arm main body 33 also has a U-shaped bearing 36 with a downwardly open side at a predetermined position immediately rearward of the first arm front connecting portion 35, and this bearing 36 rotatably engages with the first support shaft 18a of the keyboard chassis 4. Furthermore, the arm main body 33 has a first arm rear connecting portion 37 at a predetermined position rearward of the bearing 36, which connects to the second arm 32. Specifically, the first arm rear connecting portion 37 has a connecting shaft 37a that extends in the left-right direction and has both ends that protrude outward beyond the left and right side surfaces of the arm main body 33. Both ends of this connecting shaft 37a engage with connecting recesses 45b, 45b of a second arm front connecting portion 45 of the second arm 32, which will be described later.

[0036] Two elongated plate-like weights 34, 34 are attached to weight attachment portion 38 at the rear of arm main body 33, sandwiching weight attachment portion 38 from both sides. Each weight 34 is made of a material (e.g., a metal such as iron) with a higher specific gravity than arm main body 33, and is formed into a predetermined shape by pressing a metal plate, for example.

[0037] The second arm 32 is made of a resin molded product of a predetermined shape, which is injection molded from the same resin material as the arm body 33 of the first arm 31. The second arm 32 is shorter than the first arm 31 and extends a predetermined length in the front-to-rear direction. The second arm 32 also has a C-shaped bearing portion 41 near the center in the longitudinal direction, with the side surface opening forward, and this bearing portion 41 rotatably engages with the second support shaft 19a of the keyboard chassis 4.

[0038] Additionally, a second-arm rear connecting portion 42 that connects to the key rear connecting portion 23 of the white key 2a is provided at the rear of the second arm 32. This second-arm rear connecting portion 42 is bifurcated, with two left and right connecting arms 43, 43 that extend parallel to each other a predetermined length along the length 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 43. Between their rear ends, the connecting arms 43, 43 sandwich the connecting main body 23a of the key rear connecting portion 23 of the white key 2a, and each connecting hole 43a rotatably fits into the corresponding engaging protrusion 23b of the key rear connecting portion 23.

[0039] Furthermore, a second arm front connecting portion 45 is provided on the front portion of the second arm 32, which is connected 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 spaced a predetermined distance from each other in the left-right direction, and each connecting piece 45a is formed with a U-shaped connecting recess 45b whose side surface is elongated and open 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 the connecting recesses 45b, 45b, respectively.

[0040] FIG. 5(a) shows an enlarged view of the black key 2b and its key support mechanism 6b, while FIG. 5(b) shows them in exploded view. The black key 2b is injection-molded from the same resin material as the white key 2a. It is shorter than the white key 2a, extends a predetermined length in the front-to-back direction, and is hollow and open downward. The front lower end of the black key 2b is provided with a front-side connecting portion 26, which is formed in a manner similar to the front-side connecting portion 22 of the white key 2a. This front-side connecting portion 26 has a connecting recess 26a that is elongated and U-shaped and opens forward. The front-side connecting portion 26 also has an extension 26b at the front end below the connecting recess 26a, which extends a predetermined length forward beyond the front surface of the black key 2b. This extension 26b functions as an upper limit position limiter for the black key 2b. In the following description, the same components of the black key 2b and key support mechanism 6b as those of the white key 2a and key support mechanism 6a are designated by the same reference numerals, and detailed description thereof will be omitted.

[0041] The key support mechanism 6b that supports the black keys 2b is configured in a manner similar to the key support mechanism 6a for 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 identical in shape and size to the arm body 33 and second arm 32 of the key support mechanism 6a for white keys. However, the two weights 34, 34 on the left and right of the key support mechanism 6b for black keys have a different rear shape than the weight 34 of the key support mechanism 6a for white keys.

[0042] Next, we will explain the operation of the keys 2 and key support mechanism 6 in the keyboard device 1 configured as above. Figure 6 shows the operation of the white keys 2a and their key support mechanism 6a, and Figure 7 shows the operation of the black keys 2b and their key support mechanism 6b.

[0043] 6(a), when the player presses down on the front end of the white key 2a with his / her finger, the front-key connector 22 of the white key 2a moves downward, causing the first arm 31 to rotate counterclockwise around the first support shaft 18a. Accompanying the rotation of the first arm 31, the front-key connector 45 of the second arm, which engages with the connecting shaft 37a of the first arm 31 via the connecting recess 45b, moves upward. This causes the second arm 32 to rotate clockwise around the second support shaft 19a. Accompanying the rotation of the second arm 32, the rear-key connector 23 connected via the rear-key connector 42 at its rear end is pulled down, causing the rear end of the white key 2a to move downward.

[0044] During the above-described rotation of the first arm 31, as the box portion 35a of the first arm front connecting portion 35 moves downward, 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 key press information of the pressed key 2, and a sound is generated from a speaker (not shown) based on the detected key press information.

[0045] As described above, when the white key 2a is pressed down, as the first arm 31 rotates counterclockwise, the weight 34 of the first arm 31 tilts upward at the rear as shown in Figure 6(b), and its rear end abuts against the first arm upper limit stopper 10a from below, thereby preventing further rotation of the first arm 31. Then, when the front end of the white key 2a is pressed down to the lowest position, the front end of the white key 2a abuts against the key lower limit stopper 16b, preventing further depression of the white key 2a.

[0046] When the white key 2a is pressed as described above, it rotates around an imaginary fulcrum P located behind its rear end. The position of this imaginary fulcrum P is set, for example, so that 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 pressed down to the lowest position, the front end of the white key 2a is positioned a predetermined keystroke (e.g., 10 mm) lower, and the rear end of the white key 2a is positioned approximately half the keystroke (e.g., 5 mm) lower, compared to when the key is released as shown in Figure 6(a).

[0047] On the other hand, when the pressed white key 2a is released, the weight of the weight 34 causes the first arm 31 of the key support mechanism 6a to rotate in the opposite direction to that described above, and accordingly, the second arm 32 also rotates in the opposite direction to that described above. As a result, the white key 2a rotates upward around the imaginary fulcrum P. Then, a predetermined portion of the first arm 31 behind the first support shaft 18a abuts against the first arm lower limit stopper 10b from above, and both upper limit position restriction portions 21, 21 of the white key 2a abut against the key upper limit stopper 16a from below, preventing further rotation of the white key 2a and returning it to its original key-released state.

[0048] Furthermore, the operation of the black key 2b when pressed is similar to that of the white key 2a and key support mechanism 6a described above. Specifically, when the front end of the black key 2b is depressed in the key-released state shown in FIG. 7(a), the first arm 31 rotates counterclockwise around the first support shaft 18a, and the second arm 32 rotates clockwise around the second support shaft 19a, causing the black key 2b to rotate around a virtual fulcrum Q at the rear. Similar to the virtual fulcrum P of the white key 2a described above, the position of this virtual fulcrum Q is set so that its distance from the front end of the black key 2b is approximately twice the length of the black key 2 itself. Therefore, when the front end of the black key 2b is depressed to its lowest position, the front end of the black key 2b is positioned a predetermined keystroke lower than in the key-released state shown in FIG. 7(a), and the rear end of the black key 2b is positioned approximately half the keystroke lower.

[0049] On the other hand, when the pressed black key 2b is released, the first arm 31 and the second arm 32 of the key support mechanism 6b rotate in the opposite direction, causing the black key 2b to rotate upward around the virtual fulcrum Q. Then, the extension 26b of the front-key connecting portion 26 of the black key 2b abuts against the upper key stopper 17 from below, preventing further rotation of the black key 2b and returning it to its original released state.

[0050] Next, the main parts of the present invention will be described with reference to Figures 8 to 14. The main parts of the present invention are that the key support mechanism 6, which is assembled to the keyboard chassis 4 and has the first arm 31 and the second arm 32, is configured to improve assembly during manufacturing and the like, and is configured to improve disassembly during maintenance.

[0051] Fig. 8 shows an enlarged side view of second arm 32. As described above, second arm 32 is provided with C-shaped bearing portion 41 near the center in the longitudinal direction, and with second arm front coupling portion 45 at its front portion. This second arm front coupling portion 45 has a pair of left and right coupling pieces 45a, 45a (only the front one is shown in Fig. 8), and each coupling piece 45a is formed with a coupling recess 45b.

[0052] The connecting recess 45b is formed into a U-shape that opens forward, with a first protrusion 51 and a second protrusion 52 arranged above and below. The first protrusion 51 and the second protrusion 52 are spaced apart from each other in the vertical direction by a predetermined distance and protrude forward by a predetermined length. As shown in FIG. 8, the lower second protrusion 52 is formed so that its front end protrudes forward by a predetermined length s relative to the upper first protrusion 51.

[0053] 9(a) shows the state in which the first arm 31 and the second arm 32 are attached to the keyboard chassis 4, and FIG. 9(b) shows an enlarged view of the second support shaft 19a on which the second arm 32 is supported and its surroundings. The position of the second arm and the positional relationship of the bearing part 41 with the second support shaft 19a shown in FIG. 9 are those when the key 2 is not pressed (key-released state).

[0054] FIG. 10(a) shows an enlarged view of the second support shaft 19a. As shown in the figure, the second support shaft 19a has an oval cross-sectional shape, which is a circle with two notches cut out from its center. The outer peripheral surface of the second support shaft 19a is formed in an outwardly convex arc shape. The outer peripheral surface of the second support shaft 19a is composed of a pair of curved surface portions 19c, 19c that face each other at a predetermined distance, and a pair of flat surface portions 19d, 19d that are connected to the ends of the pair of curved surface portions 19c, 19c and face each other parallel to each other at a predetermined distance. Furthermore, in the second support shaft 19a, the distance D1 between the vertices of the pair of curved surface portions 19c, 19c is set to be larger than the distance D2 between the pair of flat surface portions 19d, 19d. As shown in Figure 9, this second support shaft 19a is formed so that its long axis, which passes through the axis and extends along the opposing direction of the pair of curved portions 19c, 19c, is inclined at a predetermined angle rearward (to the right in Figure 9) with respect to the vertical line.

[0055] On the other hand, as shown in FIG. 10(b), the bearing portion 41 of the second arm 32 has an inner peripheral surface 41a whose side surface is arcuate, and an opening 41b that opens to the front end side of the second arm 32. The diameter of the inner peripheral surface 41a is set to a value that is approximately the same as the distance D1 between the vertices of the pair of curved surface portions 19c, 19c of the second support shaft 19a. In other words, the inner peripheral surface 41a of the bearing portion 41 has approximately the same curvature as each of the curved surface portions 19c of the second support shaft 19a. Furthermore, the opening dimension D3 of the opening 41b of the bearing portion 41 is set to a value that is slightly larger than the distance D2 between the pair of flat surface portions 19d, 19d of the second support shaft 19a, and smaller than the distance D1 between the pair of curved surface portions 19c, 19c (D2 <D3<D1)。

[0056] 11 and 12 show the order in which the first arm 31 and the second arm 32 are attached to the keyboard chassis 4 during the manufacture of the keyboard device 1. This attachment procedure involves attaching the first arm 31 after the second arm 32 has been attached to the keyboard chassis 4 first.

[0057] As shown in Figure 11(a), first, the second arm 32 is inserted from above into the second opening 5b (see Figure 2) of the keyboard chassis 4 with the second arm 32 tilted slightly backward relative to the vertical. In this case, the opening 41b of the bearing portion 41 of the second arm 32 is aligned with the upper curved portion 19c of the second support shaft 19a of the keyboard chassis 4, and the second support shaft 19a is inserted into the bearing portion 41, as shown in Figure 11(b). In this way, the second arm 32 is attached to the second support shaft 19a in a freely rotatable state.

[0058] 11(c), the second arm 32 is rotated clockwise around the second support shaft 19a and held in a substantially horizontal position, with the connecting recess 45b of the second arm front connecting portion 45 facing slightly upward relative to the horizontal.

[0059] Next, as shown in FIG. 12(a), the first arm 31 is inserted from the front into the first opening 5a (see FIG. 2) of the keyboard chassis 4 with the arm tilted slightly downward and rearward relative to the horizontal. Then, while pushing the first arm 31 rearward, 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 FIG. 12(b). In this case, the lower second protrusion 52 of the second arm front connecting portion 45 protrudes further forward than the upper first protrusion 51. Therefore, by connecting the arms 31 and 32 while bringing the tip and inner surface of the second protrusion 52 into contact with the connecting shaft 37a of the first arm 31, the second protrusion 52 can be used as a guide, facilitating the connecting operation. In this way, the first arm 31 is rotatably and slidably connected to the second arm 32 via the connecting shaft 37a.

[0060] Then, while maintaining the first arm 31 and second arm 32 connected together, the front of the first arm 31 is moved downward as shown in Figure 12(c) and the first support shaft 18a of the keyboard chassis 4 is inserted into the bearing portion 36 of the first arm 31. This causes the first arm 31 to be attached to the first support shaft 18a in a freely rotatable state. This completes the attachment of the first arm 31 and second arm 32 to the keyboard chassis 4.

[0061] Next, referring to FIG. 13, a method of attaching the second arm 32 after first attaching the first arm 31 to the keyboard chassis 4, which is the reverse of the above-mentioned attachment procedure, will be described.

[0062] The second arm 32, which is attached to the keyboard chassis 4 using the above method, is configured to engage with the second support shaft 19a of the keyboard chassis 4 by snap-fitting via its bearing portion 41. That is, as mentioned above, although the opening dimension D3 of the opening 41b in the bearing portion 41 of the second arm 32 is smaller than the maximum diameter D1 of the second support shaft 19a (see FIG. 10), by applying a slight force to press the second arm 32 toward the second support shaft 19a while the opening 41b of the bearing portion 41 of the second arm 32 is in contact with the second support shaft 19a, the opening 41b temporarily widens, allowing the second support shaft 19a to pass through.

[0063] 13(a) shows the state in which the first arm 31 is attached to the first support shaft 18a of the keyboard chassis 4. To attach the first arm 31 to the keyboard chassis 4, as described above, the first arm 31 is inserted from the front into the first opening 5a of the keyboard chassis 4 with the first arm 31 tilted slightly downward and rearward from the horizontal, and the bearing portion 36 is engaged with the first support shaft 18a.

[0064] 13(b), the first arm 31 is rotated slightly counterclockwise around the first support shaft 18a and held in this position. In this case, the second arm 32 is inserted from above into the second opening 5b of the keyboard chassis 4, and the opening 41b of the bearing portion 41 of the second arm 32 is brought into contact with the second support shaft 19a, and the inner surface of the tip of the second protrusion 52 of the second arm front connecting portion 45 is brought into contact with the connecting shaft 37a of the first arm 31.

[0065] Then, from the above state, the second arm 32 is pushed diagonally downward and forward onto the second support shaft 19a, so that the bearing portion 41 of the second arm 32 engages with the second support shaft 19a with a snap fit, and the connecting recess 45b of the second arm front connecting portion 45 engages with the connecting shaft 37 of the first arm 31. As a result, as shown in Figure 13(c), the second arm 32 is rotatably attached to the second support shaft 19a, and is rotatably and slidably connected to the connecting shaft 37a of the first arm 31. With the above, the attachment of the first arm 31 and the second arm 32 to the keyboard chassis 4 is completed.

[0066] Next, a method for removing the first arm 31 and the second arm 32 of the key support mechanism 6 from the keyboard chassis 4 during maintenance will be described.

[0067] First, the first arm 31 and the second arm 32 attached by the procedures shown in Figures 11 and 12 can be removed from the keyboard chassis 4 by reversing the procedures shown in both figures. That is, from the state shown in Figure 12(c), the first arm 31 is removed from the first support shaft 18a of the keyboard chassis 4 (see Figure 12(b)), and then the connection of the second arm 32 with the second arm front connecting portion 45 is released (see Figure 12(a)), and the arm is pulled out to the outside of the keyboard chassis 4. After that, the second arm 32 is rotated counterclockwise as shown in Figure 11(b), and the bearing portion 41 of the second arm 32 is removed from the second support shaft 19a of the keyboard chassis 4 (see Figure 11(a)), and the arm 32 is pulled out to the outside of the keyboard chassis 4. This completes the removal of the first arm 31 and the second arm 32 from the keyboard chassis 4.

[0068] On the other hand, for the first arm 31 and the second arm 32 that are attached by the procedure shown in Figure 13 described above, that is, when the second arm 32 is configured to engage with the second support shaft 19a by snap-fitting, it is preferable to provide the second arm 32 with a tool engagement portion 53 that can be engaged with a specified tool when removing it from the second support shaft 19a.

[0069] 14 shows second arm 32A provided with tool engagement portion 53. As shown in the figure, tool engagement portion 53 is integrally provided on the upper surface of second arm 32A at a predetermined position in front of bearing portion 41, and protrudes upward by a predetermined length.

[0070] FIG. 15 shows the procedure for removing the second arm 32A from the second support shaft 19a of the keyboard chassis 4. As shown in FIG. 15(a), first, insert a rod-shaped tool T, such as a screwdriver, from above the keyboard chassis 4, and bring its tip into contact with the upper surface of the second arm 32A and the front surface of the tool engagement portion 53. Next, tilt the tool T at a predetermined angle so that the upper end of the tool T moves diagonally downward and forward. In this case, the part of the tool T that abuts against the flat portion 12a of the chassis intermediate portion 12 serves as a fulcrum, and the tip of the tool T serves as a point of application, using the principle of leverage to push the second arm 32A diagonally upward and backward. This disengages the bearing portion 41, which was engaged by a snap fit, from the second support shaft 19a. In this way, the second arm 32A, which was attached by a snap fit, can be easily removed from the keyboard chassis 4 using the tool T.

[0071] As described above, according to this embodiment, the first arm 31 and the second arm 32 can be attached to the keyboard chassis 4 relatively easily, which improves the ease of assembly during manufacturing, etc., of the key support mechanism 6 having the first arm 31 and the second arm 32. Furthermore, the first arm 31 and the second arm 32 can be removed from the keyboard chassis 4 in the reverse order of the above-described procedure, which improves the ease of disassembling the key support mechanism 6 for maintenance.

[0072] The present invention is not limited to the above-described embodiment, and can be embodied in various forms. In the embodiment, the second protrusion 52 at the front end of the second arm 32 is formed to protrude further forward than the first protrusion 51, but it is also possible to form the first protrusion 51 to protrude further forward than the second protrusion 52. Furthermore, in the second arm 32A that engages with the second support shaft 19a by snap-fitting, the tool engagement portion 53 is formed to protrude from the upper surface of the second arm 32A, but it is sufficient if the tip of the tool T can be engaged when the second arm 32A is removed. For example, the tool engagement portion can be formed in a recessed shape on the upper surface of the second arm 32A.

[0073] Furthermore, the detailed configurations of the keyboard chassis 4, key support mechanism 6, first arm 31 and second arm 32 shown in the embodiment are merely examples and can be modified as appropriate within the spirit and scope of the present invention. [Explanation of symbols]

[0074] 1 Keyboard device 2 keys 4-key chassis 5a 1st opening 5b 2nd opening 6 Key support mechanism 18 First arm support part 18a 1st spindle 19 Second arm support part 19a 2nd spindle 19c Curved surface of second support shaft 19d Flat surface of second support shaft 31 First Arm 32 Second Arm 37a Connecting shaft 41 Bearing part of second arm 41a Inner surface of bearing portion 41b Opening of bearing 45 Front connection part of second arm 45a Connecting piece 45b Connection recess 51 1st protrusion 52 Second protrusion Virtual fulcrum of P white key Q Virtual fulcrum of black key

Claims

1. Keyboard chassis and A key extending a predetermined length in the front-rear direction and disposed on the top of the keyboard chassis; a key support mechanism that engages with the keyboard chassis and supports the key from below, and that, when a key is pressed, causes the pressed key to rotate about a virtual fulcrum that is located behind the rear end of the key; Equipped with The key support mechanism includes: a first arm configured to extend a predetermined length in the front-rear direction, rotatably and detachably engaged with a first support shaft provided on the keyboard chassis, and having a front end rotatably and slidably connected to the front portion of the key; a second arm configured to extend a predetermined length in the front-to-rear direction, rotatably and detachably engaged with a second support shaft provided on the keyboard chassis rearward of the first support shaft, with its rear end rotatably connected to the rear of the key, and with its second arm front connector forward of the second support shaft rotatably, slidably and detachably connected to a first arm rear connector of the first arm rearward of the first support shaft; It has A keyboard device for a keyboard instrument, characterized in that, when attaching the first arm and the second arm to the keyboard chassis during assembly, one of the first arm and the second arm can be attached to the keyboard chassis while remaining rotatably engaged with the keyboard chassis, and the other of the first arm and the second arm can be connected to the one of the first arm and the second arm.

2. the second arm front connecting portion has a first protruding portion and a second protruding portion spaced apart by a predetermined distance and protruding forward of the second arm by a predetermined length, the second arm front connecting portion is open forward of the second arm, and has a U-shaped side surface; 2. The keyboard device for a keyboard instrument according to claim 1, wherein a front end portion of one of the first protrusion and the second protrusion is formed so as to protrude further forward than a front end portion of the other of the first protrusion and the second protrusion.

3. 3. The keyboard device for a keyboard instrument according to claim 1, wherein the second arm has a C-shaped side surface and a bearing portion that is engaged with the second support shaft by snap-fitting.

4. 4. The keyboard device for a keyboard instrument according to claim 3, wherein the second arm is provided with a tool engagement portion with which a predetermined tool is engaged when the second arm is removed from the keyboard chassis for maintenance.

Images