Keyboard device for keyboard instruments

Abstract

To provide a keyboard device of a keyboard instrument capable of suppressing occurrence of bounding of keys by suppressing bounding when a rotating hammer returns to its original position in linking with depression of keys and capable of reducing generation of noise by the hammer.SOLUTION: A keyboard device includes: a hammer 31 rotating vertically in linking with a pressed key 2; and a cushion 52 that is provided below the hammer 31, and with which the hammer 31 comes into contact from above when the hammer 31 rotating upward following depression of keys returns to its original position following release of keys. The hammer 31 has multiple projections 51 that are mutually separated with a gap and project downward each toward the rear from a hammer support shaft 18a. The cushion 52 is composed of multiple cushions 52a, 52b, 52c, and 52d that successively come into contact toward those away from the hammer support shaft 18a from those close to it among the multiple projections 51 when the hammer 31 comes into contact from above.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a keyboard device for a keyboard instrument such as an electronic piano, which is equipped with hammers that rotate in conjunction with the depression of a key. [Background technology]

[0002] A keyboard device of this type is known, for example, from Patent Document 1. In this keyboard device, a hammer is rotatably mounted below each key extending in the front-rear direction. When the key is released, each hammer extends in the front-rear direction with a downward tilt toward the rear, and its rear end abuts against a stopper from above. The stopper is composed of a stopper rail extending horizontally in the left-right direction and a buffer material on the top surface of the stopper rail, the cross section of which is formed into a constant rectangular shape along the entire length.

[0003] In a keyboard device having such a stopper, when a key is pressed, the hammer corresponding to that key rotates in a predetermined direction, and the rear end of the hammer moves above the stopper. When the key is released, the hammer rotates in the opposite direction, and the rear end of the hammer abuts against the stopper from above. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-10374 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-described keyboard device, only one stopper is provided at a position corresponding to the rear end of the hammer. In this case, the rear end of the rotating hammer is farthest from the fulcrum of the hammer's rotation, resulting in a large amount of kinetic energy when it strikes the stopper. As a result, the hammer is likely to bounce when it strikes the stopper, and it may take a long time to completely stop. As a result, the top surface of the key corresponding to that hammer may vibrate up and down until the hammer completely stops, a phenomenon known as bouncing. Another problem is that the rear end of the hammer, which has a large amount of kinetic energy, strikes a single stopper, which can easily generate noise.

[0006] 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 suppress the occurrence of key bounce by suppressing the bounce when the hammer, which rotates in conjunction with the key being pressed, returns to its original position, and can also suppress the generation of noise caused by the hammer. [Means for solving the problem]

[0007] In order to achieve the above object, the invention of claim 1 comprises a keyboard chassis, keys extending in the front-to-rear direction and arranged on the upper part of the keyboard chassis, hammers extending in the front-to-rear direction and rotatably supported on the keyboard chassis below the keys via hammer spindles, and rotating up and down in conjunction with the keys being pressed, and cushions provided below the hammers, on which the hammers are placed when the keys are released, and against which the hammers come into contact from above when the hammers, having rotated upward when the keys are pressed, return to their original position when the keys are released, the hammers having a plurality of convex parts formed rearward from the hammer spindle at intervals from one another and each protruding downward, and the cushions are composed of a plurality of cushions corresponding to the plurality of convex parts, and which come into contact with the plurality of convex parts in order from those closest to the hammer spindle to those furthest from the hammer spindle when the hammers come into contact from above.

[0008] According to this configuration, when the hammer rotates upward upon key depression and returns to its original position upon key release, the hammer abuts against the cushion from above. The hammer has multiple protrusions spaced apart from one another and projecting downward from the hammer pivot toward the rear, while the cushion is composed of multiple cushions corresponding to the multiple protrusions on the hammer. When the multiple protrusions on the hammer abut against the corresponding cushions, they abut against the corresponding cushions in order, starting from the protrusion closest to the hammer pivot and proceeding from the protrusion furthest away. This gradually reduces the kinetic energy of the rotating hammer through the multiple cushions, thereby suppressing the hammer from bouncing when all of the hammer's protrusions abut against the cushions. As a result, even when the key is configured to move in tandem with the hammer, key bouncing can be suppressed. Furthermore, when the hammer abuts against the cushion, as described above, the hammer abuts against the multiple cushions in order, gradually reducing the speed and momentum of the rotating hammer. This reduces noise compared to conventional systems in which the hammer abuts against a single stopper.

[0009] The invention according to claim 2 is characterized in that in the keyboard device for a keyboard instrument according to claim 1, at least one of the plurality of protrusions is formed in a downwardly tapered shape.

[0010] With this configuration, at least one of the multiple protrusions is tapered downward, so when the protrusion of the hammer contacts the corresponding cushion from above, the contact area between the protrusion and the cushion can be made to gradually increase, which makes it possible to reduce noise when the hammer contacts the cushion compared to when the contact area between the hammer and the cushion is large from the start.

[0011] The invention of claim 3 is characterized in that, in the keyboard device of the keyboard instrument described in claim 1, the multiple cushions are made of an elastic material with lower resilience the closer they are to the hammer spindle.

[0012] With this configuration, the cushions against which the hammer's protrusions respectively contact are made of an elastic material with lower resilience the closer they are to the hammer spindle, effectively suppressing noise when the protrusions contact the cushions while gradually reducing the kinetic energy of the rotating hammer, thereby effectively suppressing noise when the hammer contacts the cushions and key bounce.

[0013] The invention of claim 4 is a keyboard device for a keyboard instrument as defined in any one of claims 1 to 3, characterized in that the hammer has a hammer body made of synthetic resin, extending in the front-to-rear direction and supported rotatably on the hammer spindle, and a weight made of metal, extending in the front-to-rear direction, attached to the rear of the hammer body and formed so as to extend rearward beyond the rear end of the hammer body, and the hammer body and weight are provided with at least one of a plurality of convex portions.

[0014] According to this configuration, in a hammer having a hammer body made of synthetic resin and a weight made of metal, the hammer body and the weight are each provided with at least one protrusion that abuts against a cushion. As a result, by using elastic materials suitable for the hammer body and the weight as cushions against which the protrusions of the hammer body and the weight abut, respectively, it is possible to effectively mitigate the impact when the hammer abuts. [Brief explanation of the drawings]

[0015] [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] 3A and 3B are diagrams for explaining the main parts of the present invention, in which (a) is a cross-sectional view similar to FIG. 3B, (b) is an enlarged view of the rear part of the first arm and its surroundings, and (c) is an enlarged view of only the rear part of the first arm. [Figure 9] 10A to 10C are diagrams sequentially showing states in which a plurality of protrusions on the rear portion of the first arm come into contact with the cushion. DETAILED DESCRIPTION OF THE INVENTION

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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).

[0043] 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.

[0044] 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.

[0045] 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.

[0046] Next, the main features of the present invention will be described with reference to Figures 8 and 9. The main features of the present invention are that the first arm 31 (hammer) of each key 2 is provided with a plurality of protrusions 51 at the rear, and a plurality of cushions 52 against which the protrusions 51 respectively contact from above.

[0047] 8(a) and 8(b), the keyboard device 1 of the present invention has four protrusions 51 spaced apart in the front-to-rear direction at the rear (right side in FIG. 8(a)) of the first arm 31 of each key 2. Additionally, four cushions 52 fixed onto the rear rail 9 are provided below these four protrusions 51, respectively.

[0048] In the following description, the four protrusions 51 will be referred to as the first protrusion 51a, the second protrusion 51b, the third protrusion 51c, and the fourth protrusion 51d, in order from the front side (left side in Figure 8) closest to the first support shaft 18a (hammer support shaft), and the four cushions 52 will be referred to as the first cushion 52a, the second cushion 52b, the third cushion 52c, and the fourth cushion 52d, in order from the front side.

[0049] As shown in Figure 8(c), the first protrusion 51a and the second protrusion 51b protrude downward by a predetermined length and are formed integrally with the hammer body 33. The first protrusion 51a has a flat bottom surface, while the second protrusion 51b is tapered downward.

[0050] The third convex portion 51c and the fourth convex portion 51d protrude downward by a predetermined length and are formed integrally with the weight 34. The third convex portion 51c has a flat bottom surface, while the fourth convex portion 51d is tapered downward.

[0051] On the other hand, the four cushions 52 are made of an elastic material such as urethane, extend a predetermined length in the left-right direction (front-to-back direction in Figure 8) along the rear rail 9, and have a constant rectangular cross section throughout the entire length, with a horizontal top surface.

[0052] The four cushions 52 are configured so that the closer they are to the first support shaft 18a, the lower their resilience is. That is, of the four cushions 52, the first cushion 52a has the lowest resilience and the fourth cushion 52d has the highest resilience.

[0053] 9A and 9B show how the four protrusions 51 of the first arm 31 sequentially contact the corresponding cushions 52 from above when the first arm 31, which has rotated upward in response to a key depression, returns to its original position in response to a key release. Specifically, as shown in FIG. 9A, the first protrusion 51a of the first arm 31 first contacts the first cushion 52a. Then, as shown in FIG. 9B, the second protrusion 51b contacts the second cushion 52b. Next, as shown in FIG. 9C, the third protrusion 51c contacts the third cushion 52c. Finally, as shown in FIG. 9D, the fourth protrusion 51d contacts the fourth cushion 52d. Thus, when the first arm 31 having the four protrusions 51 contacts the four cushions 52 from above, the protrusions 51 closest to the first support shaft 18a contact the corresponding cushions 52 in order.

[0054] In the keyboard device 1 having the first arm 31 with the four convex portions 51 and the four cushions 52 configured as described above, when the four convex portions 51 of the first arm 31 abut against the four cushions 52, the kinetic energy of the rotating first arm 31 is gradually reduced by the four cushions 52, thereby suppressing the bounding of the first arm 31 when all of the convex portions 51 of the first arm 31 abut against the cushions 52. As a result, the occurrence of bouncing, in which the upper surface of the key 2 that is linked to the rotation of the first arm 31 vibrates up and down, is suppressed. Furthermore, when the first arm 31 abuts against the cushions 52, the first arm 31 abuts against the four cushions 52a to 52d in order, gradually reducing the speed and momentum of the rotating first arm 31. This suppresses the generation of noise compared to conventional systems in which the hammer abuts against a single stopper.

[0055] Furthermore, since the second protrusion 51b and the fourth protrusion 51d of the four protrusions 51 of the first arm 31 are tapered downward, these protrusions 51b, 51d come into contact with the corresponding cushions 52b, 52d so that the contact area gradually increases. This makes it possible to suppress the generation of noise when the first arm 31 comes into contact with the cushion 52, compared to when the contact area when the first arm 31 comes into contact with the cushion 52 is large from the beginning.

[0056] Furthermore, the four cushions 52 are configured so that the closer they are to the first support shaft 18a, the lower their resilience, which effectively suppresses noise generated when each protrusion 51 of the first arm 31 abuts against the cushion 52, while gradually reducing the kinetic energy of the rotating first arm 31. This effectively suppresses noise generated when the first arm 31 abuts against the cushion 52 and bouncing of the key 2.

[0057] The present invention is not limited to the above-described embodiment, but can be embodied in various forms. For example, in the embodiment, four protrusions 51 are provided on the first arm 31, and four corresponding cushions 52 are provided, but the present invention is not limited to this, and the number of protrusions 51 on the first arm 31 can be two, three, or five or more. In these cases, cushions 52 are provided according to the number of protrusions 51.

[0058] Furthermore, in the embodiment, the present invention has been described as being applied to a keyboard device 1 in which a depressed key 2 rotates around virtual fulcrums P and Q at the rear, but the present invention is not limited to this and can of course also be applied to a general keyboard device in which the key rotates around its own rear end and does not have a second arm 32. Furthermore, the detailed configurations of the first arm 31, protrusion 51, and cushion 52 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]

[0059] 1 Keyboard device 2 keys 4-key chassis 9 Rear rail 18a First spindle (hammer spindle) 31 First Arm (Hammer) 33 Arm body 34 Weight 51 Convex part 51a First convex part 51b Second convex part 51c Third convex part 51d 4th convex part 52 cushion 52a First cushion 52b Second cushion 52c Third cushion 52d Fourth cushion Virtual fulcrum of P white key Q Virtual fulcrum of black key

Claims

1. Keyboard chassis and A key extending in the front-rear direction and disposed on the upper part of the keyboard chassis; a hammer extending in the front-rear direction, rotatably supported by the keyboard chassis via a hammer support shaft below the key, and rotating up and down in conjunction with the key being pressed; a cushion provided below the hammer, on which the hammer is placed when the key is released, and against which the hammer abuts from above when the hammer returns to its original position after rotating upward in response to key depression; Equipped with The hammer has a plurality of protrusions formed rearward from the hammer spindle at intervals from one another and each protruding downward, a keyboard device for a keyboard instrument, characterized in that the cushions are composed of a plurality of cushions that respectively correspond to the plurality of protrusions and abut against the plurality of protrusions in order from those closest to the hammer spindle to those furthest from the hammer spindle when the hammer abuts against them from above.

2. 2. The keyboard device for a keyboard instrument according to claim 1, wherein at least one of the plurality of protrusions is tapered downward.

3. 2. The keyboard device for a keyboard instrument according to claim 1, wherein the plurality of cushions are made of an elastic material having a lower resilience the closer they are to the hammer spindle.

4. The hammer a hammer body made of synthetic resin, extending in the front-rear direction, and rotatably supported on the hammer support shaft; a weight made of metal, extending in the front-rear direction, attached to the rear of the hammer body, and extending rearward beyond the rear end of the hammer body; It has 4. The keyboard device for a keyboard instrument according to claim 1, wherein the hammer body and the weight are provided with at least one of the plurality of protrusions.

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