Keyboard mechanism of a keyboard instrument

Abstract

To provide a keyboard device of a keyboard instrument that can prevent noise from being generated at a connection part between a first arm and a second arm of a key support mechanism when a key is pressed and also secure smooth action of the connection part so as to impart an excellent touch feeling.SOLUTION: A keyboard device of a keyboard instrument comprises a keyboard chassis 4, a key 2 which is arranged thereon, and a key support mechanism 6 which supports the key 2 from below and allows the key to act to rotate around virtual fulcra P, Q, wherein a first arm rear-side connection part 37 has a connection shaft 37a extending to the right and left, a second arm front-side connection part 45 has an engagement recessed part 45b which has its side face formed in a U shape to be open to the front and engages with the connection shaft 37a, and the engagement recessed part 45b is fitted with an upper buffer member 51 and a lower buffer member 52 which slide in contact with an outer peripheral surface of an engagement shaft 37a while covering an upper part and a lower part of its inner surface, respectively.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a keyboard device for a keyboard musical instrument that is applied to a keyboard musical instrument such as an electronic piano, and operates such that a depressed key rotates around a virtual fulcrum located behind the rear end of the key.

Background Art

[0002] Conventionally, as this type of keyboard device, for example, the keyboard device disclosed in Patent Document 1, which was previously filed by the present applicant, is known. This keyboard device includes a key extending in the front-rear direction, and a link mechanism that supports the key from below. The link mechanism has a front connecting link bar and a rear connecting link bar, each extending a predetermined length in the front-rear direction. A front end portion of the front connecting link bar is rotatably connected to a front portion of the key, while a rear end portion of the rear connecting link bar is rotatably connected to a rear end portion of the key. Each of the connecting link bars described above is rotatably supported via a support pin provided near the center in the length direction, and a rear end portion of the front connecting link bar and a front end portion of the rear connecting link bar are connected to each other rotatably and slidably. More specifically, an elongated hole is formed in the rear end portion of the front connecting link bar, while a central connecting pin that is inserted into the elongated hole is protruded from the front end portion of the rear connecting link bar.

[0003] In the keyboard device configured as described above, when the front end portion of the key is depressed, each connecting link bar of the link mechanism rotates in a predetermined direction around the support pin. In this case, the central connecting pin of the rear connecting link bar slides along the length direction of the elongated hole of the front connecting link bar while rotating. When the front end portion of the key is depressed to the lowest position, the rear end portion of the key is positioned downward by a distance approximately half of that of the front end portion. Accordingly, the key operates to rotate around a virtual fulcrum located rearward at a distance approximately equal to the length of the key itself. As a result, while the length of the key is configured to be shorter than that of a key of an acoustic grand piano, a key operation similar to that of the keyboard of a grand piano can be obtained.

Prior Art Literature

Patent Literature

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-52391 (Figures 3-5) [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In the conventional keyboard mechanism described above, each connecting link bar of the link mechanism is made of a hard material such as metal. Therefore, depending on the relationship between the diameter of the central connecting pin of the rear connecting link bar and the width of the elongated hole in the front connecting link bar, proper key operation may not be possible. Specifically, if the diameter of the central connecting pin is smaller than the width of the elongated hole, and a relatively large gap is created between the central connecting pin and the side of the elongated hole in the width direction, noise may be generated when the key is pressed as the central connecting pin hits the side of the elongated hole. Conversely, if there is almost no gap, the central connecting pin cannot slide smoothly against the elongated hole, and as a result, the touch when pressing down the key may become heavy.

[0006] Furthermore, in the above-mentioned keyboard device, when a key is pressed, for example, near the center along its length, the responsiveness of the front connecting link bar may decrease due to the structure of the link mechanism that supports the key from below. In that case, a good touch sensation may not be obtained.

[0007] The present invention was made to solve the above-mentioned problems, and aims to provide a keyboard device for a keyboard instrument that can prevent the generation of noise at the connection between the first arm and the second arm of the key support mechanism when the key is pressed, and ensure smooth operation of the connection, thereby providing a good touch feel. [Means for solving the problem]

[0008] To achieve the above objective, the invention according to claim 1 comprises a keyboard chassis, a key extending a predetermined length in the front-rear direction and positioned on the upper part of the keyboard chassis, and a key support mechanism that engages with the keyboard chassis and is provided to support the key from below, and when the key is pressed, causes the pressed key to rotate around a virtual pivot point located behind the rear end of the key, wherein the key support mechanism is configured to extend a predetermined length in the front-rear direction and is pivotably engaged with a first pivot shaft provided on the keyboard chassis, and its front end is rotatably and slidably connected to the front of the key, and is configured to extend a predetermined length in the front-rear direction and pivots on a second pivot shaft provided on the keyboard chassis behind the first pivot shaft The device has a second arm that engages freely and whose rear end is rotatably connected to the rear of the key, and whose front connecting portion of the second arm, which is forward of the second support shaft, is rotatably and slidably connected to the rear connecting portion of the first arm, which is backward of the first support shaft of the first arm, and one of the rear connecting portion of the first arm and the front connecting portion of the second arm has an engagement shaft that extends in the left-right direction, and the other of the rear connecting portion of the first arm and the front connecting portion of the second arm is formed in a U-shape with its side shape open in one direction in the front-rear direction, and has an engagement recess that engages with the engagement shaft, and an upper cushioning member and a lower cushioning member are attached to the engagement recess so as to cover the upper and lower parts of the inner surface thereof, respectively, and slide in contact with the outer surface of the engagement shaft.

[0009] In this configuration, the key, which extends a predetermined length in the front-to-back direction and is positioned on the upper part of the keyboard chassis, is supported from below by the key support mechanism having the first and second arms described above, and operates to rotate around a virtual pivot point located behind the rear end of the key when pressed. In the key support mechanism, the rear connecting portion of the first arm and the front connecting portion of the second arm are rotatably and slidably connected. One of these rear connecting portion of the first arm and front connecting portion of the second arm has an engagement shaft extending in the left-to-right direction, and the other has a U-shaped engagement recess whose side shape is open in one direction in the front-to-back direction. An upper cushioning member and a lower cushioning member are attached to the engagement recess, covering the upper and lower parts of its inner surface, respectively, and slidingly contacting the outer surface of the engagement shaft. By attaching the upper and lower cushioning members to the engagement recess in this way, the engagement recess does not directly contact the outer surface of the engagement shaft, and therefore, the generation of noise at the connection between the first and second arms of the key support mechanism when the key is pressed can be prevented. Furthermore, since the upper and lower cushioning members attached to the engagement recesses slide against the engagement shaft, smooth movement can be ensured at the connection between the first and second arms, thereby providing a good tactile feel when pressing the key.

[0010] The invention according to claim 2 is characterized in that, in the keyboard device of the keyboard instrument described in claim 1, the upper cushioning member and the lower cushioning member are configured to have different cushioning properties from each other.

[0011] With this configuration, by configuring the upper and lower cushioning members to have different cushioning properties, the touch feel can be easily adjusted so that a good touch feel can be obtained regardless of the position of the fingertip when the key is pressed down. In this specification, cushioning properties include the hardness of the upper and lower cushioning members, the elastic modulus, and / or the coefficient of friction of the surface that slides against the engaging shaft.

[0012] The invention according to claim 3 is characterized in that, in the keyboard device of the keyboard instrument described in claim 2, the lower cushioning member is made harder than the upper cushioning member.

[0013] With this configuration, the lower cushioning member is made harder than the upper cushioning member, so when, for example, the back of the key is pressed down, a good operational response can be obtained from the first arm, and as a result, a responsive touch can be obtained. [Brief explanation of the drawing]

[0014] [Figure 1] This is a perspective view showing a part (one octave) of the keyboard mechanism of an electronic piano to which the present invention is applied, where (a) shows the external appearance of the keyboard mechanism, and (b) shows the state with all keys except the leftmost white and black keys omitted. [Figure 2] Figure 1(b) is a perspective view showing the keyboard device with the white keys and black keys removed from the keyboard chassis, along with their respective key support mechanisms. [Figure 3] (a) is a plan view of the keyboard device shown in Figure 1(b), and (b) is a cross-sectional view along line AA. [Figure 4] This is a perspective view showing the white keys and key support mechanism; (a) shows the white keys and key support mechanism connected, and (b) shows the white keys and key support mechanism disassembled. [Figure 5] This is a perspective view showing the black keys and key support mechanism; (a) shows the black keys and key support mechanism connected, and (b) shows the black keys and key support mechanism disassembled. [Figure 6] This diagram illustrates the operation of the white keys in a keyboard mechanism, with (a) showing the released state and (b) showing the pressed state. [Figure 7] This diagram illustrates the operation of the black keys in a keyboard mechanism, with (a) showing the released state and (b) showing the pressed state. [Figure 8] These figures illustrate the main parts of the present invention; (a) is a perspective view showing a white key and its key support mechanism, (b) shows the second arm of the key support mechanism, and (c) shows the state with the upper and lower cushioning members removed from the second arm. [Figure 9] It is a right side view of the second arm, and an enlarged cross-sectional view of the upper buffer member and the lower buffer member. [Figure 10] It is a cross-sectional view similar to FIG. 3(b), showing a state where the upper buffer member and the lower buffer member are attached to the second arm. [Figure 11] It is a diagram for explaining forces acting on the key and the second arm due to a difference in the depressed position of the key when the key is pressed, wherein (a) shows a case where the front end of the key is pressed down, and (b) shows a case where the deep side of the key is pressed down. [Figure 12] It is a perspective view illustrating an example of the lower buffer member configured to have a different buffering property from the upper buffer member. MODE FOR CARRYING OUT THE INVENTION

[0015] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1(a) shows only one octave portion of a keyboard device 1 of an electronic piano to which the present invention is applied. In the following description, first, the basic configuration and operation of the keyboard device 1 will be described, and then the essential parts of the present invention will be described.

[0016] FIG. 1(b) shows a state where keys 2 other than the leftmost white key 2a and black key 2b are omitted in the keyboard device 1 of FIG. 1(a), and FIG. 2 shows a state where the white key 2a and the black key 2b together with a key support mechanism 6 are removed from a keyboard chassis 4.

[0017] The keyboard device 1 includes the keyboard chassis 4, a plurality of keys 2 including the white key 2a and the black key 2b arranged side by side in the left-right direction, the key support mechanism 6 rotatably attached to the keyboard chassis 4 for each key 2 and supporting the corresponding key 2 from below, a key switch 3 for detecting key depression information of each key 2, and the like.

[0018] The keyboard chassis 4 includes a chassis body 4a made of a resin molded product of a predetermined shape, formed by injection molding of a predetermined resin material (e.g., ABS resin). As shown in Figure 3, the front part 11, middle part 12, and rear part 13 of this chassis body 4a are all formed to extend in the left-right direction (left-right direction in Figure 3(a)), and these are integrally molded by a plurality of ribs 14 that are spaced apart in the left-right direction and each extends in the front-back direction. In the following description, the front part 11, middle part 12, and rear part 13 of the chassis body 4a of the keyboard chassis 4 will be referred to as "chassis front part 11," "chassis middle part 12," and "chassis rear part 13," respectively.

[0019] The front part 11 of the chassis is primarily for guiding the white keys 2a when pressed and for regulating the upper and lower limits of their front ends. Multiple white key guides 11a are installed on the front part 11 of the chassis, arranged horizontally, and inserted from below for each white key 2a to prevent lateral movement of the white keys 2a. Furthermore, the front part 11 of the chassis is provided with engagement holes 11b, 11b that penetrate vertically on both the left and right sides of each white key guide 11a, and the two upper limit position regulating parts 21, 21 of the white key 2a, described later, engage with these engagement holes 11b, 11b, respectively, with the left and right sides penetrating through them. In addition, the front part 11 of the chassis is provided with a stopper mounting part 11c that protrudes forward and extends horizontally across the entire chassis body 4a, and a key upper limit stopper 16a and a key lower limit stopper 16b for the white keys are attached to the lower and upper surfaces of this stopper mounting part 11c, respectively, so as to extend horizontally. Furthermore, the front part 11 of the chassis is provided with a stopper mounting portion 11d for black keys that extends horizontally across the entire chassis body 4a at a predetermined position behind the white key guide 11a, and a key upper limit stopper 17 for black keys is attached to this stopper mounting portion 11d so as to extend horizontally.

[0020] The chassis intermediate section 12 primarily guides the black keys 2b when pressed and pivotably supports the first arm 31 and second arm 32 of the key support mechanisms 6a and 6b for the white and black keys, which will be described later. This chassis intermediate section 12 has a flat plate-shaped section 12a extending in the left-right direction, and a plurality of black key guides 12b erected on this flat section 12a and arranged at appropriate intervals in the left-right direction. Each black key guide 12b is inserted from below for each black key 2b, preventing the black key 2b from swinging laterally. In addition, a first arm support section 18 is provided at the front of the chassis intermediate section 12 to support the first arm 31 of the key support mechanism 6. This first arm support section 18 has a plurality of first support shafts 18a that are provided between adjacent ribs 14, 14 so as to extend in the left-right direction, and the first arm 31 is pivotably supported on these first support shafts 18a. Furthermore, a second arm support section 19 is provided at the rear of the chassis intermediate section 12 to support the second arm 32 of the key support mechanism 6. This second arm support section 19 has a plurality of second support shafts 19a that are provided between adjacent ribs 14, 14 and extend in the left-right direction. The plurality of second support shafts 19a are arranged on the same axis extending in the left-right direction, at a position rearward and higher than the first support shaft 18a, and the second arm 32 is pivotably supported on these second support shafts 19a. A first arm lower limit stopper 10b is provided at a predetermined position on the middle rail 8, which will be described later, located on the lower side of the chassis intermediate section 12, and extends in the left-right direction across the entire chassis body 4a.

[0021] Furthermore, the key switch 3 is mounted on the lower part of the keyboard chassis 4, between the front part 11 and the middle part 12 of the chassis. This key switch 3 consists of a horizontally elongated printed circuit board 3a extending in the left-right direction, and a plurality of switch bodies 3b, each consisting of a rubber switch mounted on this printed circuit board 3a for each key 2, which is pressed by the first arm 31 when the key is pressed.

[0022] The rear chassis portion 13 primarily serves to guide the key 2 vertically while preventing lateral movement at its rear end, and to regulate the upper limit position of the rear end of the first arm 31. As shown in Figures 2 and 3(a), the rear chassis portion 13 has multiple partition walls 13a spaced apart from each other in the left-right direction to separate adjacent keys 2, 2. Furthermore, as shown in Figure 3(b), a first arm upper limit stopper 10a is provided at a predetermined position on the upper part of the rear chassis portion 13, extending horizontally across the entire chassis body 4a. This first arm upper limit stopper 10a and the first arm lower limit stopper 10b provided in the middle portion 12 of the chassis are, respectively, for regulating the upper limit position when the first arm 31, which functions as a hammer for applying touch weight to the key 2, rotates upward, and the lower limit position when it rotates downward. Furthermore, a metal cover plate 15 is attached to the upper part of the rear section 13 of the chassis, extending horizontally across the entire chassis body 4a and positioned to cover the rear end of the key 2.

[0023] As shown in Figures 2 and 3(a), the chassis body 4a of the keyboard chassis 4 configured as described above is provided with a plurality of first openings 5a that open upward and forward, and a plurality of second openings 5b that open upward. Through each of the first openings 5a, the first arm 31 of the key support mechanism 6 is engaged with the first support shaft 18a from the outside, and through each of the second openings 5b, the second arm 32 is engaged with the second support shaft 19a from the outside.

[0024] Furthermore, in the keyboard chassis 4 described above, multiple chassis bodies 4a are connected to each other in a left-right direction, and are screwed to metal front rails 7, middle rails 8, and rear rails 9, which extend in the left-right direction and are arranged at predetermined intervals from each other in the front-back direction. The keyboard chassis 4 is then fixed to a shelf (not shown) of the electronic piano via the front rails 7 and rear rails 9.

[0025] Next, the key 2 and the key support mechanism 6 will be described. Figure 4(a) shows an enlarged view of the white key 2a and its key support mechanism 6a, and Figure 4(b) shows them in an exploded view. As shown in the figure, the white key 2a is formed by injection molding of a predetermined resin material (e.g., AS resin) to extend a predetermined length in the front-rear direction and to be hollow and open downwards. The front end of the white key 2a is provided with a pair of left and right upper limit position restricting parts 21, 21 that extend downwards from the left and right side walls and whose lower ends are bent forward. As described above, these upper limit position restricting parts 21, 21 engage with the left and right engagement holes 11b, 11b of the front part 11 of the chassis, respectively, by penetrating them.

[0026] Furthermore, a key front connecting portion 22 is provided at the front of the white key 2a at a predetermined position behind the upper limit position restricting portion 21, and is connected to the first arm 31 of the key support mechanism 6a. This key front connecting portion 22 has a connecting recess 22a that is formed in a U-shape with an elongated hole shape on its side and opens forward. A cushioning member 20 is also attached to this connecting recess 22a so as to cover its entire inner circumferential surface, in order to suppress the generation of noise when the connecting shaft 35b of the first arm 31 (described later) slides within the connecting recess 22a. A keyboard weight 30 (see Figure 3) is attached to the front of the white key 2a between the upper limit position restricting portion 21 and the key front connecting portion 22 to impart a desired touch weight when the key is pressed.

[0027] Furthermore, a rear key connecting portion 23 is provided at the rear of the white key 2a, which is connected to the second arm 32 of the key support mechanism 6a. This rear key connecting portion 23 hangs downward from the center of the white key 2a in the left-right direction and has a plate-shaped connecting body portion 23a having a predetermined thickness in the left-right direction, and a pair of left and right engaging protrusions 23b, 23b that protrude coaxially from the left and right sides of the connecting body portion 23a, respectively. In addition, a tool insertion hole 24 is formed at the rear of the white key 2a, which penetrates in the vertical direction, and is used to insert a predetermined tool from above when releasing the connection between the white key 2a and the second arm 32 of the key support mechanism 6a during maintenance of the keyboard device 1.

[0028] On the other hand, the key support mechanism 6a includes a first arm 31 and a second arm 32 that engage with each other and are connected to the front key connecting portion 22 and the rear key connecting portion 23 of the white key 2a, respectively.

[0029] As shown in Figure 4(b), the first arm 31 consists of an arm body 33 and two weights 34, 34 attached to the arm body 33. The arm body 33 is made of a resin molded product of a predetermined shape, such as by injection molding a predetermined resin material (e.g., polyacetal). The arm body 33 extends a predetermined length in the front-rear direction, and a first arm front connecting portion 35 is provided at its front end, which connects to the key front connecting portion 22 of the white key 2a. The first arm front connecting portion 35 has a box-shaped box portion 35a that opens upward and forward, and a connecting shaft 35b that extends in the left-right direction, connecting the front upper ends of the left and right side walls of the box portion 35a. The connecting shaft 35b is rotatably and slidably connected in the front-rear direction to the connecting recess 22a of the key front connecting portion 22 of the white key 2a.

[0030] Furthermore, the arm body 33 has a U-shaped bearing portion 36 with a side shape that opens downward at a predetermined position immediately behind the first arm front connecting portion 35, and this bearing portion 36 rotatably engages with the first support shaft 18a of the keyboard chassis 4. In addition, the arm body 33 is provided with a first arm rear connecting portion 37 that connects to the second arm 32 at a predetermined position behind the bearing portion 36. Specifically, the first arm rear connecting portion 37 has a connecting shaft 37a that extends in the left-right direction, with both ends protruding outward from the left and right sides of the arm body 33. Both ends of this connecting shaft 37a engage with the connecting recesses 45b, 45b of the second arm front connecting portion 45 of the second arm 32, which will be described later.

[0031] Two elongated, plate-shaped weights 34, 34 are attached to the weight attachment section 38 at the rear of the arm body 33, sandwiching the weight attachment section 38 from both sides. Each weight 34 is made of a material with a higher specific gravity than the arm body 33 (for example, a metal such as iron), and is formed into a predetermined shape by pressing a metal plate.

[0032] The second arm 32 is made of a resin molded product of a predetermined shape by injection molding the same resin material as the arm body 33 of the first arm 31. This second arm 32 is shorter than the first arm 31 and extends for a predetermined length in the front-rear direction. The second arm 32 also has a C-shaped bearing portion 41 near the center in the longitudinal direction, with its side shape opening forward, and this bearing portion 41 rotatably engages with the second support shaft 19a of the keyboard chassis 4.

[0033] Furthermore, the rear end of the second arm 32 is provided with a second arm rear connecting portion 42 that connects to the key rear connecting portion 23 of the white key 2a. This second arm rear connecting portion 42 is formed in a bifurcated shape and has two left and right connecting arm portions 43, 43 that extend parallel to each other for a predetermined length along the length direction of the second arm 32. A connecting hole 43a that penetrates in the left-right direction is formed at the rear end of each connecting arm portion 43. The two connecting arm portions 43, 43 sandwich the connecting body portion 23a of the key rear connecting portion 23 of the white key 2a from both sides between their rear ends, and each connecting hole 43a is rotatably fitted into the corresponding engaging projection 23b of the key rear connecting portion 23.

[0034] Furthermore, the front of the second arm 32 is provided with a second arm front connecting portion 45 that connects to the first arm rear connecting portion 37 of the first arm 31. This second arm front connecting portion 45 has a pair of left and right connecting pieces 45a, 45a separated from each other at a predetermined distance in the left-right direction, and each connecting piece 45a has a U-shaped connecting recess 45b formed therein that has an elongated hole shape on its side and opens forward. The left and right connecting pieces 45a, 45a of the second arm front connecting portion 45 are rotatably and slidably engaged with both ends of the connecting shaft 37a of the first arm 31 via their connecting recesses 45b, 45b.

[0035] Figure 5(a) shows an enlarged view of the black key 2b and its key support mechanism 6b, while Figure 5(b) shows them in an exploded view. The black key 2b is formed by injection molding of the same resin material as the white key 2a, making it shorter than the white key 2a, extending a predetermined length in the front-to-back direction, and forming a hollow shape that opens downwards. The front lower end of the black key 2b is provided with a key front connecting portion 26, which is formed in substantially the same way as the key front connecting portion 22 of the white key 2a. This key front connecting portion 26 has a connecting recess 26a that is formed in a U-shape with an elongated hole shape on its side and opens forwards. Furthermore, the key front connecting portion 26 has an extension portion 26b at the lower front end of the connecting recess 26a that extends a predetermined length forward from the front surface of the black key 2b body, and this extension portion 26b functions as an upper limit position regulating portion for the black key 2b. In the following explanation, the same reference numerals will be used for the black keys 2b and key support mechanism 6b as for the white keys 2a and key support mechanism 6a described above, and detailed explanations will be omitted.

[0036] The key support mechanism 6b that supports the black key 2b is configured in almost the same way as the key support mechanism 6a for the white keys described above. Specifically, the arm body 33 of the first arm 31 and the second arm 32 of the key support mechanism 6b are configured to be exactly the same shape and size as the arm body 33 and the second arm 32 of the key support mechanism 6a for the white keys. The two weights 34, 34 on the left and right of the key support mechanism 6b for the black keys are shown to be the same as the weights 34, 34 of the key support mechanism 6b for the white keys, but their shape and length are appropriately changed according to the touch weight required for the key 2.

[0037] Next, the operation of the keys 2 and key support mechanisms 6 in the keyboard device 1 configured as described above will be explained. Figure 6 shows the operation of the white keys 2a and their key support mechanisms 6a, and Figure 7 shows the operation of the black keys 2b and their key support mechanisms 6b.

[0038] In the unlocked state shown in Figure 6(a), when the front end of the white key 2a is pressed down by the player's finger, the front key connecting portion 22 of the white key 2a moves downward, causing the first arm 31 to rotate counterclockwise around the first pivot shaft 18a. As the first arm 31 rotates, the front second arm connecting portion 45, which engages with the connecting shaft 37a of the first arm 31 via the connecting recess 45b, moves upward. As a result, the second arm 32 rotates clockwise around the second pivot shaft 19a. With this rotation of the second arm 32, the rear key connecting portion 23, which is connected via the rear second arm connecting portion 42 at its rear end, is pulled down, causing the rear end of the white key 2a to move downward.

[0039] Furthermore, when the first arm 31 rotates as described above, the box portion 35a of the front connecting portion 35 of the first arm moves downward, and the bottom wall of the box portion 35a presses from above against the switch body 3b of the key switch 3 corresponding to the pressed key 2. As a result, the electronic piano detects the key press information of the pressed key 2, and based on the detected key press information, sound is generated from a speaker (not shown).

[0040] As described above, when the white key 2a is pressed down, the weight 34 of the first arm 31 tilts upward and backward as the first arm 31 rotates counterclockwise, as shown in Figure 6(b), and its rear end contacts the first arm upper limit stopper 10a from below. This prevents the first arm 31 from rotating any further. When the front end of the white key 2a is pressed down to its lowest position, the front end of the white key 2a contacts the key lower limit stopper 16b, preventing the white key 2a from being pressed any further down.

[0041] As described above, the pressed white key 2a operates to rotate around a virtual pivot point P located behind its rear end. The position of this virtual pivot point P is set such that, for example, the distance from the front end of the white key 2a is approximately twice the length of the white key 2a itself. As a result, when the front end of the white key 2a is pushed down to its lowest position, the front end of the white key 2a is located lower by a predetermined key stroke (e.g., 10 mm) and the rear end is located lower by a distance of approximately half the key stroke (e.g., 5 mm) compared to the released state shown in Figure 6(a).

[0042] On the other hand, when the finger is released from the pressed-down white key 2a, the weight of the weight 34 causes the first arm 31 of the key support mechanism 6a to rotate in the opposite direction, and consequently, the second arm 32 also rotates in the opposite direction. As a result, the white key 2a rotates upward around the virtual pivot point P. Then, a predetermined portion of the first pivot shaft 18a on the first arm 31 comes into contact with the first arm lower limit stopper 10b from above, and both upper limit position restricting parts 21, 21 of the white key 2a come into contact with the key upper limit stopper 16a from below, preventing further rotation of the white key 2a and returning it to its original released state.

[0043] Furthermore, the operation of the black key 2b when pressed is the same as that of the white key 2a and the key support mechanism 6a described above. That is, in the released state shown in Figure 7(a), when the front end of the black key 2b is pressed down, the first arm 31 rotates counterclockwise around the first pivot shaft 18a, and the second arm 32 rotates clockwise around the second pivot shaft 19a, causing the black key 2b to rotate around a virtual pivot point Q at the rear. The position of this virtual pivot point Q is set, for example, so that the distance from the front end of the black key 2b is approximately twice the length of the black key itself, similar to the virtual pivot point P of the white key 2a described above. Therefore, when the front end of the black key 2b is pressed down to its lowest position, the front end of the black key 2b is located lower by a predetermined key stroke, and the rear end is located lower by a distance of approximately half the key stroke, compared to the released state shown in Figure 7(a).

[0044] On the other hand, when the finger is released from the pressed-down black key 2b, the first arm 31 and the second arm 32 of the key support mechanism 6b rotate in the opposite direction, and consequently, the black key 2b rotates upward around the virtual pivot point Q. Then, the extended portion 26b of the key front connecting portion 26 of the black key 2b comes into contact with the key upper limit stopper 17 from below, preventing further rotation of the black key 2b and returning it to its original unlocked state.

[0045] Next, the main parts of the present invention will be described with reference to Figures 8 to 11. The main part of the present invention is that, in the second arm 32 of the key support mechanism 6, an upper cushioning member 51 and a lower cushioning member 52 are provided at the front connecting portion 45 of the second arm, which is the connecting portion with the first arm 31, and which slide against the connecting shaft 37a (engagement shaft) of the first arm 31.

[0046] Figure 8(a) shows the white key 2a and its key support mechanism 6a, Figure 8(b) shows the second arm 32 of the key support mechanism 6a, and Figure 8(c) shows the state in which the upper cushioning member 51 and the lower cushioning member 52 have been removed from the second arm 32.

[0047] Both the upper cushioning member 51 and the lower cushioning member 52 are made of molded articles of a predetermined elastic synthetic resin (e.g., thermoplastic elastomer).

[0048] As shown in Figure 8(c), the upper cushioning member 51 has two rectangular tube portions 51a, 51a extending a predetermined length in the front-rear direction, a connecting portion 51b connecting the upper rear ends of both rectangular tube portions 51a, 51a, and locking portions 51c protruding rearward from the rear end of each rectangular tube portion 51a. The upper cushioning member 51 is attached to the front arm connecting portion 45 of the second arm, with the upper protruding portions 45U, 45U of the left and right connecting pieces 45a, 45a of the second arm, respectively, inserted into the two rectangular tube portions 51a, 51a, and each locking portion 51c being locked to the rear upper part of the front arm connecting portion 45 of the second arm, 45. As a result, the upper cushioning member 51 is securely attached to the front arm connecting portion 45 of the second arm, covering the upper part of the inner surface of the connecting recesses 45b, 45b of the left and right connecting pieces 45a, 45a.

[0049] On the other hand, the lower cushioning member 52 is configured in substantially the same way as the upper cushioning member 51 described above, and has two rectangular tube portions 52a, 52a extending a predetermined length in the front-rear direction, a connecting portion 52b connecting the rear ends of both rectangular tube portions 52a, 52a, and a locking portion 52c extending a predetermined length rearward from the rear end of each rectangular tube portion 52a. The lower cushioning member 52 is attached to the front second arm connecting portion 45 with the lower protruding portions 45D, 45D of the left and right connecting pieces 45a, 45a of the front second arm connecting portion 45 being inserted into the two rectangular tube portions 52a, 52a, respectively, and with each locking portion 52c being locked to the rear lower part of the front second arm connecting portion 45. As a result, the lower cushioning member 52 is securely attached to the front connecting portion 45 of the second arm, covering the lower part of the inner surfaces of the connecting recesses 45b, 45b in the left and right connecting pieces 45a, 45a.

[0050] Figure 9 shows a right side view of the second arm 32 to which the upper cushioning member 51 and the lower cushioning member 52 are attached, and also shows an enlarged cross-section of both cushioning members 51 and 52. As shown in the figure, at the front connecting portion 45 of the second arm to which both cushioning members 51 and 52 are attached, the lower surface of the rectangular tube portion 51a of the upper cushioning member 51 slides against the connecting shaft 37a at the rear connecting portion 37 of the first arm 31, and the upper surface of the rectangular tube portion 52a of the lower cushioning member 52 slides against it. In the following description, the lower surface of each rectangular tube portion 51a of the upper cushioning member 51 will be appropriately referred to as the "lower sliding contact surface 51d," and the upper surface of each rectangular tube portion 52a of the lower cushioning member 52 will be appropriately referred to as the "upper sliding contact surface 52d."

[0051] Figure 10 is a diagram of the keyboard device 1, similar to Figure 3(b) described above, showing the state in which the upper cushioning member 51 and the lower cushioning member 52 described above are attached to the front connecting portion 45 of the second arm 32. Figure 11 also shows the force acting on the key 2 and the second arm 32 due to differences in the pressed position of the key 2 when the key is pressed, using the keyboard device 1 shown in Figure 10.

[0052] As shown in Figure 11(a), when the front end of the key 2 is pushed down (see black arrow), the connecting shaft 35b, which is the connection part with the first arm 31, functions as a fulcrum, causing the rear end of the key 2 to attempt to rotate upward (see arc-shaped white arrow). Consequently, a force acts on the second arm 32, which is connected to the rear end of the key 2 via the engaging projection 23b, causing it to rotate counterclockwise around the second pivot shaft 19a as shown in Figure 11(a) (see white arrow at the rear end of the second arm 32). In this case, in the second arm 32, the lower sliding contact surface 51d of the upper cushioning member 51, one of the upper and lower cushioning members 51 attached to the front connecting part 45 of the second arm, is strongly pressed against the connecting shaft 37a, which is the connection part with the first arm 31 (see white arrow at the front end of the second arm 32), causing the connecting shaft 37a to slide towards the back of the connecting recess 45b.

[0053] On the other hand, as shown in Figure 11(b), when the rear side of key 2 is pushed down (see black arrow), the connecting shaft 35b acts as a fulcrum in key 2, causing the rear end of key 2 to rotate downward (see arc-shaped white arrow). Consequently, a force acts on the second arm 32 connected to the rear end of key 2, causing it to rotate clockwise around the second support shaft 19a as shown in Figure 11(b) (see white arrow at the rear end of the second arm 32). In this case, unlike the case in Figure 11(a) described above, the upper sliding contact surface 52d of the lower buffer member 52 of the second arm 32 is strongly pressed against the connecting shaft 37a of the first arm 31 (see white arrow at the front end of the second arm 32), causing the connecting shaft 37a to slide towards the rear side of the connecting recess 45b.

[0054] The difference in the pressing position of the key 2 described above can lead to the following problems. Specifically, as shown in Figure 11(a), when the front end of the key 2 is pressed down, the first arm 31 rotates with good responsiveness, but as shown in Figure 11(b), when the rear end of the key 2 is pressed down, the responsiveness of the first arm 31 decreases, and the desired touch sensation may not be obtained. One possible reason for this is that the cushioning properties of the upper cushioning member 51 and the lower cushioning member 52 attached to the second arm 32 are the same.

[0055] Therefore, by configuring the upper cushioning member 51 and the lower cushioning member 52 to have different cushioning properties, the touch feel when the back side of the key 2 is pressed down is adjusted. For example, by making the lower cushioning member 52 out of a harder material than the upper cushioning member 51, a good operational response of the first arm 31 can be obtained when the back side of the key 2 is pressed down, and as a result, a responsive touch feel can be obtained.

[0056] As described above, according to the keyboard device 1 to which the essential parts of the present invention are applied, an upper cushioning member 51 and a lower cushioning member 52 are attached to the front connecting portion 45 of the second arm 32, covering the upper and lower parts of the inner surface of the connecting recess 45b, respectively, and the connecting shaft 37a of the first arm 31 slides against the lower sliding contact surface 51d of the upper cushioning member 51 and the upper sliding contact surface 52d of the lower cushioning member 52. As a result, the connecting shaft 37a of the first arm 31 does not directly contact the inner surface of the connecting recess 45b of the second arm 32, and therefore, the generation of noise at the connecting portion between the first arm 31 and the second arm 32 of the key support mechanism 6 can be prevented when pressing a key. Furthermore, smooth operation at the connecting portion between the first arm 31 and the second arm 32 can be ensured, thereby providing a good touch when pressing a key.

[0057] Furthermore, as mentioned above, by configuring the upper cushioning member 51 and the lower cushioning member 52 to have different cushioning properties, it is possible to adjust the touch sensation when the back side of the key 2 is pressed down.

[0058] Figure 12 illustrates a lower cushioning member 52 configured to have different cushioning properties than the upper cushioning member 51. In the lower cushioning member 52A shown in Figure 12(a), two grooves 61, 61 extending along the entire length are formed on the upper surface of each rectangular tube 52a. In the lower cushioning member 52B shown in Figure 12(b), numerous protrusions 62 are formed on the upper surface of each rectangular tube 52a. Furthermore, in the lower cushioning member 52C shown in Figure 12(c), two grooves 63, 63 extending along the entire length are formed on the inner ceiling surface of each rectangular tube 52a. By configuring the lower cushioning member 52 in this way, even if the lower cushioning member 52 is made of the same material as the upper cushioning member 51, it is relatively easy to obtain a lower cushioning member 52 with different cushioning properties than the upper cushioning member 51.

[0059] The detailed configurations of the keyboard device 1, key 2, key support mechanism 6, upper cushioning member 51, and lower cushioning member 52 shown in the embodiment are merely illustrative examples and can be modified as appropriate within the scope of the present invention. [Explanation of Symbols]

[0060] 1 Keyboard device 2 keys 2a white key 2b black key 4-key chassis 4a Chassis body 6 Key support mechanism 6a Key support mechanism for white keys 6b Key support mechanism for black keys 18a 1st spindle 19a 2nd spindle 31. First Arm 32. Second Arm 37. Rear connection section of the first arm 37a Connection shaft (engaging shaft) 45 Front connecting section of the second arm 45a Connecting piece 45b Connecting recess 45U upper protrusion 45D Lower protrusion 51 Upper buffer member 51a Corner tube section 51d Lower side folded surface 52 Lower buffer material 52a Corner section 52d upper folded surface

Claims

1. Keyboard chassis and A key extending a predetermined length in the front-to-back direction and positioned on the upper part of the keyboard chassis, A key support mechanism is provided to engage with the keyboard chassis and support the key from below, and when a key is pressed, it causes the pressed key to rotate around a virtual pivot point located behind the rear end of the key. Equipped with, The aforementioned key support mechanism is A first arm is configured to extend a predetermined length in the front-rear direction, and is pivotably engaged with a first support shaft provided on the keyboard chassis, with its front end rotatably and slidably connected to the front of the key, A second arm is configured to extend a predetermined length in the front-rear direction, and is pivotably engaged with a second support shaft provided on the keyboard chassis behind the first support shaft, with its rear end rotatably connected to the rear of the key, and the front connecting portion of the second arm, which is forward of the second support shaft, being rotatably and slidably connected to the rear connecting portion of the first arm, which is behind the first support shaft. It has, One of the rear connecting portion of the first arm and the front connecting portion of the second arm has an engagement shaft extending in the left-right direction. The other of the first arm rear connecting portion and the second arm front connecting portion is formed in a U-shape with a side shape that opens in one direction in the front-rear direction, and has an engaging recess that engages with the engaging shaft. A keyboard device for a keyboard instrument, characterized in that an upper cushioning member and a lower cushioning member are attached to the engagement recess, respectively, covering the upper and lower parts of its inner surface, and slidingly contacting the outer circumferential surface of the engagement shaft.

2. The keyboard device for a keyboard instrument according to claim 1, characterized in that the upper cushioning member and the lower cushioning member are configured to have different cushioning properties from each other.

3. The keyboard device for a keyboard instrument according to claim 2, characterized in that the lower cushioning member is made harder than the upper cushioning member.

Images