JP7717564B2 - Keyboard device for keyboard instruments - Google Patents

Description

The present invention relates to a keyboard device for keyboard instruments such as electronic pianos, which is equipped with hammers that rotate in conjunction with the depression of keys.

A known example of this type of keyboard device is described in Patent Document 1. This keyboard device includes a key that extends in the front-to-rear direction and rotates around its rear end as a fulcrum; a mass body that also extends in the front-to-rear direction and is rotatably mounted below the key and rotates in response to key depression; and a key frame that rotatably supports the key and mass body. A downwardly protruding driving piece is provided at the front of the key, and an elastic member is attached to the lower end of this driving piece. Meanwhile, the front end of the mass body is U-shaped with a side that opens forward, and includes upper and lower engagement pieces that protrude forward and are spaced apart vertically. The lower end of the key's driving piece is engaged between the upper and lower engagement pieces via an elastic member.

In the above keyboard device, when a key is pressed, the mass body corresponding to that key rotates while its front end is pressed downward. When that key is released, the mass body rotates while its front end moves upward, returning together with the key to its original position before the key was pressed.

Japanese Patent Application Laid-Open No. 2007-52400

However, in the above keyboard device, when a pressed key is released, the mass body that rotates in conjunction with the key may bounce due to inertia, and at that time, the lower end of the key's driving hanging piece, specifically the part of the driving hanging piece that holds the elastic member, may come into direct contact with the upper or lower engagement piece of the mass body. Because the driving hanging piece and the upper and lower engagement pieces of the mass body are generally made of hard synthetic resin, the collision between them when the key is pressed can generate noise.

In addition, the elastic member attached to the key's driving hanging piece has arcuate surfaces with different curvatures at its upper and lower parts, and the upper and lower arcuate surfaces contact the upper and lower engagement pieces of the mass body, respectively. An elastic member with such arcuate surfaces cannot move smoothly between the upper and lower engagement pieces of the mass body when the key is pressed, which can result in a heavy feel when pressing the key.

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 noise from being generated at the connection between the key and the hammer when the key is pressed, while also ensuring smooth operation of that connection, thereby providing a good feel for the touch.

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, and hammers extending in the front-to-rear direction, rotatably supported on the keyboard chassis below the keys via hammer spindles, and rotating in conjunction with the depressed keys. The keys and hammers are each provided with a key-side connecting portion and a hammer-side connecting portion forward of the hammer spindle, which are rotatably and slidably connected to each other. One of the key-side connecting portion and the hammer-side connecting portion has an engagement shaft extending in the left-to-right direction, and the other has a U-shaped side that opens to one side in the front-to-rear direction and has an engagement recess that engages with the engagement shaft. The engagement recess is fitted with a buffer member that prevents the engagement shaft from hitting its inner surface and makes sliding contact with the engagement shaft.

According to this configuration, the key and hammer are provided with a key-side connecting portion and a hammer-side connecting portion, respectively, which are connected to each other so as to be freely rotatable and slidable. One of the key-side connecting portion and the hammer-side connecting portion has an engagement shaft extending left and right, while the other has a U-shaped side that opens in one direction, front and rear, and an engagement recess that engages with the engagement shaft. A buffer member is attached to the engagement recess to prevent the engagement shaft from hitting its inner circumferential surface. This prevents the engagement shaft from directly hitting the inner circumferential surface of the engagement recess when the key is pressed, preventing noise from being generated. Furthermore, because the key-side connecting portion and the hammer-side connecting portion are connected by the engagement shaft and the engagement recess with the buffer member attached, smooth operation at the connection portion is ensured when the key is pressed, resulting in a good touch.

The invention of claim 2 is characterized in that, in the keyboard device of the keyboard instrument described in claim 1, the buffer member is composed of a molded product made of elastic synthetic resin, and has an upper wall mounting portion attached to the upper wall of the engagement recess so as to cover its underside, a lower wall mounting portion attached to the lower wall of the engagement recess so as to cover its upper surface, and connecting portions connected to the upper wall mounting portion and the lower wall mounting portion, respectively, and provided to cover the inner surface of the back wall of the engagement recess.

With this configuration, the buffer member is made of a molded, elastic synthetic resin, making it relatively inexpensive and easy to manufacture. Furthermore, because the buffer member has the upper wall mounting portion, lower wall mounting portion, and connecting portion described above, by attaching the upper wall mounting portion and lower wall mounting portion to the upper and lower walls of the engagement recess, respectively, the entire inner surface of the engagement recess can be easily covered by the buffer member.

The invention of claim 3 is characterized in that, in the keyboard device of the keyboard instrument described in claim 2, the upper wall mounting portion and the lower wall mounting portion are attached to the engagement recess with the tip ends of the upper wall and lower wall of the engagement recess inserted into them, respectively .

According to this configuration, the cushioning member can be easily attached to the engagement recess by inserting the tip ends of the upper and lower walls of the engagement recess into the upper wall attachment portion and lower wall attachment portion of the cushioning member, respectively .

The invention of claim 4 is characterized in that, in the keyboard device for a keyboard instrument described in claim 3, the engagement recess is provided in the key, and one of the upper and lower walls of the engagement recess protrudes forward beyond the buffer member and is configured to abut from below against a stopper that determines the upper limit position of the key when the key is released.

With this configuration, an engagement recess is provided on the key. Furthermore, one of the upper and lower walls of the engagement recess abuts from below against a stopper that defines the upper limit position of the key when the key is released, preventing the key from moving upward any further and stabilizing the key's position when the key is released. Furthermore, even when a buffer member is attached to the key's engagement recess, the key's stable position when the key is released can be ensured.

The invention of claim 5 is characterized in that, in the keyboard device for a keyboard instrument described in any one of claims 2 to 4, the lower surface of the upper wall mounting portion and the upper surface of the lower wall mounting portion are configured to be parallel, and the engagement shaft has a circular cross section and is positioned so as to slide against the lower surface of the upper wall mounting portion and the upper surface of the lower wall mounting portion.

With this configuration, the lower surface of the upper wall mounting portion of the buffer member is parallel to the upper surface of the lower wall mounting portion. The engagement shaft has a circular cross section and is in sliding contact with the lower surface of the upper wall mounting portion and the upper surface of the lower wall mounting portion. As a result, when a key is pressed, the engagement shaft rotates and slides smoothly relative to the engagement recess while in sliding contact with the buffer member. This ensures smooth operation of the connection between the key and hammer when the key is pressed.

The invention of claim 6 is characterized in that, in the keyboard device for a keyboard instrument described in claim 5, lubricant retaining grooves for retaining lubricant are formed on the lower surface of the upper wall mounting portion and the upper surface of the lower wall mounting portion.

With this configuration, lubricant-retaining grooves are formed on the underside of the upper wall mounting portion and the upper side of the lower wall mounting portion of the buffer member. By applying lubricant to the inner surface of the buffer member attached to the engagement recess, the lubricant can be retained for a long period of time on the underside of the upper wall mounting portion and the upper side of the lower wall mounting portion of the buffer member. This ensures smooth operation of the connection between the key and hammer, via the engagement shaft and engagement recess, for a long period of time.

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 external appearance of the keyboard device, and (b) shows a state in which keys other than the white key and black key on the left end are omitted. 2 is a perspective view showing the keyboard device shown in FIG. 1B in a state where the white keys and black keys, together with their respective key support mechanisms, have been removed from the keyboard chassis. FIG. 1(a) is a plan view of the keyboard device shown in FIG. 1(b), and FIG. 1(b) is a cross-sectional view taken along line AA. 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. 1A and 1B are perspective views showing a black key and a 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. 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. 1A and 1B are diagrams for explaining the operation of black keys in a keyboard device, in which FIG. 1A shows a key-released state and FIG. 1B shows a key-depressed state. 1A and 1B are perspective views for explaining the main parts of the present invention, in which (a) shows an enlarged view of the connection portion between the key and the first arm, and (b) shows the state in which the key and the first arm are separated and the buffer member is removed from the key. 5A, 5B, and 5C are enlarged views of the buffer member, in which FIG. 5A is a perspective view, FIG. 5B is a front view, and FIG. 5C is a side view. 4A and 4B are enlarged cross-sectional views of the connecting portion between the key and the first arm, in which FIG. 4A shows the key released state and FIG. 4B shows the key pressed state.

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

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 side, 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.

This keyboard device 1 includes a keyboard chassis 4, a plurality of keys 2, each 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 press information for each key 2.

The keyboard chassis 4 includes a chassis main body 4a made of a resin molded product of a predetermined shape, typically by injection molding a predetermined resin material (e.g., ABS resin). As shown in Figure 3, the front portion 11, middle portion 12, and rear portion 13 of this chassis main body 4a are all formed to extend in the left-right direction (left-right direction in Figure 3(a)) as a whole, and are integrally molded with a plurality of ribs 14 that are spaced apart in the left-right direction and each extend 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.

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

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 below) of the key support mechanisms 6a, 6b for the white and black keys. The chassis intermediate section 12 has a flat, plate-like section 12a extending laterally, and multiple black key guides 12b standing on the flat section 12a and spaced appropriately apart laterally. 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 also 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 has multiple first support shafts 18a extending laterally between adjacent ribs 14, 14. The first arms 31 are swingably supported by these first support shafts 18a. Furthermore, a second arm support section 19 that supports the 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 multiple second support shafts 19a that extend in the left-right direction between adjacent ribs 14, 14. The multiple 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. 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 the middle rail 8 (described below) that is provided below the chassis intermediate section 12.

The key switch 3 is attached to the bottom of the keyboard chassis 4, between the chassis front section 11 and chassis middle section 12. This 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 this printed circuit board 3a for each key 2. When a key is pressed, the rubber switches are pressed by the first arm 31.

The chassis rear section 13 primarily serves to guide the key 2 vertically at its rear end while preventing lateral movement, 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 chassis rear section 13 has multiple partition walls 13a spaced at predetermined intervals in the left-right direction to separate adjacent keys 2, 2. Also, as shown in Figure 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 respectively regulate the upper limit position of the first arm 31, which functions as a hammer for applying touch weight to the key 2, when the first arm 31 rotates upward and the lower limit position when the first arm 31 rotates downward. Furthermore, a metal cover plate 15 is attached to the top of the rear chassis 13, extending left and right across the entire chassis body 4a and positioned to cover the rear end of the key 2.

As shown in Figures 2 and 3(a), the chassis body 4a of the keyboard chassis 4 configured as described above has a plurality of first openings 5a that open upward and forward, and a plurality of second openings 5b that 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.

In addition, in the keyboard chassis 4, multiple chassis bodies 4a are connected to each other 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, which all extend left-right and are arranged at a predetermined distance from each other in the front-to-back direction. The keyboard chassis 4 is then fixed to the shelf board (not shown) of the electronic piano via the front rails 7 and rear rails 9.

Next, the key 2 and 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, while Figure 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 mentioned above, these upper limit position restrictors 21, 21 engage with the left and right engagement holes 11b, 11b on the front chassis 11 while passing through them, respectively.

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

Furthermore, the rear of the white key 2a is provided with a key rear connector 23 that connects to the second arm 32 of the key support mechanism 6a. This key rear connector 23 hangs downward from the left-right center of the white key 2a and has a plate-shaped connector main 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 main body 23a. The rear of the white key 2a also has a tool insertion hole 24 that penetrates vertically and is used to insert a specific tool from above when releasing the connection between the white key 2a and the second arm 32 of the key support mechanism 6a, such as during maintenance of the keyboard device 1.

On the other hand, the key support mechanism 6a has 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.

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 formed 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.

The arm 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. This bearing 36 rotatably engages with the first support shaft 18a on the keyboard chassis 4. Furthermore, the arm body 33 also 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 sides of the arm body 33. Both ends of this connecting shaft 37a engage with connecting recesses 45b, 45b of the second arm front connecting portion 45 of the second arm 32, which will be described later.

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

The second arm 32 is made of a resin molded product of a predetermined shape, 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. Near the center of its length, the second arm 32 also has a C-shaped bearing portion 41 with a side that opens forward, and this bearing portion 41 rotatably engages with the second support shaft 19a on the keyboard chassis 4.

The rear 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 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. The rear end of each connecting arm 43 is formed with a connecting hole 43a that penetrates in the left-right direction. 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.

Furthermore, a second arm front connecting portion 45 is provided at the front of the second arm 32, which 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 spaced a predetermined distance from each other in the left-right direction, and each connecting piece 45a has a U-shaped connecting recess 45b whose side is elongated and open to the front. The left and right connecting pieces 45a, 45a of the second arm front connecting portion 45 rotatably and slidably engage with both ends of the connecting shaft 37a of the first arm 31 via these connecting recesses 45b, 45b.

Figure 5(a) shows an enlarged view of the black key 2b and its key support mechanism 6b, while Figure 5(b) shows them exploded. The black key 2b is injection-molded from the same resin material as the white key 2a, and 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 with an elongated side shape and a U-shaped opening toward the front. Furthermore, the front-side connecting portion 26 has an extension portion 26b at the front end below the connecting recess 26a, which extends a predetermined length forward beyond the front surface of the main body of the black key 2b. This extension portion 26b functions as an upper limit position limiter for the black key 2b. In the following explanation, the same components of the black keys 2b and key support mechanism 6b as those of the white keys 2a and key support mechanism 6a described above will be assigned the same reference numerals, and detailed explanations will be omitted.

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

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

In the key-released state shown in Figure 6(a), when the player presses down on the front end of the white key 2a with their 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. As the first arm 31 rotates, 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. As the second arm 32 rotates, the rear-key connector 23, which is 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.

When the first arm 31 rotates as described above, the box portion 35a of the first arm front connecting portion 35 moves downward, causing the bottom wall of the box portion 35a to press 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 a sound is generated from a speaker (not shown) based on the detected key press information.

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 the first arm upper limit stopper 10a from below. This prevents the first arm 31 from rotating further. 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 the key lower limit stopper 16b, preventing the white key 2a from being pressed down any further.

When a white key 2a is pressed in this manner, it rotates around an imaginary fulcrum P, which is 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 its lowest position, the front end of the white key 2a is positioned a predetermined keystroke (e.g., 10 mm) lower than when the key is released as shown in Figure 6(a), and the rear end is positioned approximately half the keystroke (e.g., 5 mm) lower.

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 the second arm 32 also rotates in the opposite direction. 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 restricting 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 released state.

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. That is, when the front end of the black key 2b is pressed down 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. As a result, the black key 2b rotates around the virtual fulcrum Q at the rear. Note that, like 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 pressed down to its lowest position, the front end of the black key 2b is positioned a predetermined keystroke lower, and the rear end is positioned approximately half the keystroke lower, compared to the key-released state shown in FIG. 7(a).

On the other hand, when the pressed black key 2b is released, the first arm 31 and second arm 32 of the key support mechanism 6b rotate in the opposite direction, causing the black key 2b to rotate upward around the imaginary 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.

Next, the main features of the present invention will be described with reference to Figures 8 to 10. The main feature of the present invention is that the buffer member 20 is attached to the connecting recesses 22a, 26a (engagement recesses) at the key front connecting portions 22, 26 (key side connecting portions) of the key 2, which connect to the first arm front connecting portion 35 (hammer side connecting portion) of the first arm 31 in the key support mechanism 6. Note that the connecting recess 22a of the white key 2a and the connecting recess 26a of the black key 2b are configured in almost the same way, so the following explanation will focus on the connecting recess 22a of the white key 2a as a representative example, and will focus on attaching the buffer member 20 to this.

Figure 8(a) shows an enlarged view of the connection portion between the key 2 and the first arm 31, while Figure 8(b) shows the connection portion between the key 2 and the first arm 31 separated and the buffer member 20 removed from the connection recess 22a of the front-key connection portion 22 of the key 2. As shown in Figure 8(b), the connection recess 22a of the key 2 is formed into a U-shape with a forward-opening side by an upper wall 22b, a lower wall 22c, and a rear wall 22d. Specifically, the upper wall 22b and the lower wall 22c face each other at a predetermined vertical distance, and their opposing surfaces are parallel. The rear wall 22d is connected to the rear ends of the upper wall 22b and the lower wall 22c, and has an arc-shaped side.

Figure 9 shows an enlarged view of the buffer member 20. The buffer member 20 is composed of a molded product made of a specific elastic synthetic resin (e.g., a thermoplastic elastomer). As shown in the figure, the buffer member 20 has an upper wall mounting portion 51 that is attached to the upper wall 22b of the connecting recess 22a of the key 2, a lower wall mounting portion 52 that is attached to the lower wall 22c of the connecting recess 22a, and a connecting portion 53 that connects to the rear end of each of the upper wall mounting portion 51 and the lower wall mounting portion 52.

The upper wall mounting portion 51 is formed in a rectangular cylindrical shape extending a predetermined length in the front-to-rear direction. The ceiling of the upper wall mounting portion 51 has a notch 51a that opens to the rear. Meanwhile, the lower wall mounting portion 52, like the upper wall mounting portion 51, is also formed in a rectangular cylindrical shape. The bottom of the lower wall mounting portion 52 has a through-hole 52a that penetrates in the vertical direction. Furthermore, the rear end of the bottom surface of the lower wall mounting portion 52 has a downwardly protruding convex portion 52d. The lower surface 51b of the upper wall mounting portion 51 and the upper surface 52b of the lower wall mounting portion 52 are parallel to each other, and two lubricant retaining grooves 51c and 52c are formed on each of the lower surface 51b and upper surface 52b, extending parallel to each other in the front-to-rear direction.

The connecting portion 53 is connected to the bottom of the upper wall mounting portion 51 and the ceiling of the lower wall mounting portion 52, and is curved convexly backward, with a side surface formed in an arc shape with approximately the same curvature as the back wall 22d of the connecting recess 22a on the key 2 side.

The cushioning member 20 configured as described above is attached to the connecting recess 22a by inserting the upper wall 22b and lower wall 22c of the connecting recess 22a into the upper wall mounting portion 51 and lower wall mounting portion 52 from the rear, respectively. In this case, the upper wall mounting portion 51 of the cushioning member 20 is attached to the upper wall 22b of the connecting recess 22a so as to cover its underside, with the tip of the upper wall 22b inserted and the upper upright portion of the upper wall 22b inserted into the notch 51a. Meanwhile, the lower wall mounting portion 52 is attached to the lower wall 22c so as to cover its upper side, with the tip of the lower wall 22c of the connecting recess 22a inserted and the bottom of the lower wall 22c fitted into the through-hole 52a. The connecting portion 53 is provided to cover the inner surface of the rear wall 22d of the connecting recess 22a.

Figure 10 shows an enlarged cross section of the connection between the key 2 and the first arm 31, with (a) showing the key in the released state and (b) showing the key in the pressed state. As shown in Figure 10 (a), when the buffer member 20 is attached to the connecting recess 22a of the key 2, the entire inner surface of the connecting recess 22a is covered by the buffer member 20. Furthermore, the connecting shaft 35b of the first arm 31 connected to the key 2 has a circular cross section and is in sliding contact with the lower surface 51b of the upper wall mounting portion 51 and the upper surface 52b of the lower wall mounting portion 52 of the buffer member 20, and is located near the connecting portion 53 in the released state.

When the key 2 is pressed in the above-described key-released state, the front-key connecting portion 22 of the key 2 moves downward. Accordingly, the connecting shaft 35b of the first arm 31 also moves downward, causing the first arm 31 to rotate counterclockwise around the first support shaft 18a, as described above. In this case, the connecting shaft 35b slides forward relative to the connecting recess 22a of the key 2, as shown in Figure 10(b).

When the pressed key 2 is then released, the first arm 31 rotates in the opposite direction, and the connecting shaft 35b moves upward and slides backward relative to the connecting recess 22a, returning the key 2 and first arm 31 to their original released state.

In this case, as shown in FIG. 5, the black key 2b has an extension 26b that protrudes forward from the lower wall of the connecting recess 26a, which corresponds to the lower wall 22c of the connecting recess 22a of the white key 2a, and extends further forward than the lower wall mounting portion 52. As shown in FIG. 10(a), the extension 26b abuts against the upper key stopper 17 (stopper) for the black key from below. This prevents the black key 2a from moving upward any further, stabilizing the position of the black key 2b when the key is released.

As described above, with the keyboard device 1 incorporating essential features of the present invention, the buffer member 20 is attached to the connecting recess 22a of the key 2, preventing the connecting shaft 35b of the first arm 31 from directly hitting the inner surface of the connecting recess 22a when the key is pressed, thereby preventing noise generation. Furthermore, the connecting shaft 35b and the connecting recess 22a to which the buffer member 20 is attached connect the front-key connecting portion 22 and the front-first-arm connecting portion 35, ensuring smooth operation of the connecting portions 22, 35 when the key is pressed, resulting in a good touch.

Furthermore, by attaching the buffer member 20, which has an upper wall mounting portion 51, a lower wall mounting portion 52, and a connecting portion 53, to the connecting recess 22a of the key 2, the entire inner surface of the connecting recess 22a can be easily covered and the buffer member can be easily and securely attached to the connecting recess 22a.

Furthermore, lubricant-retaining grooves 51c, 52c are provided on the underside 51b of the upper wall mounting portion 51 and the upper side 52b of the lower wall mounting portion 52 of the buffer member 20. Therefore, by applying lubricant to the buffer member 20 attached to the connecting recess 22a, the lubricant can be retained for a long period of time on the underside 51b of the upper wall mounting portion 51 and the upper side 52b of the lower wall mounting portion 52. This ensures smooth operation of the connection between the key 2 and the first arm 31, via the connecting shaft 35b and connecting recess 22a, for a long period of time.

The present invention is not limited to the above-described embodiment and can be implemented in various forms. For example, in the embodiment, the connecting recess 22a is provided in the key front connecting portion 22 of the key 2, and the connecting shaft 35b is provided in the first arm front connecting portion 35 of the first arm 31. However, it is also possible to reverse the positional relationship between the engaging connecting recess 22a and the connecting shaft 35b, i.e., to provide the connecting recess on the first arm 31 and the connecting shaft on the key 2. In the embodiment, the connecting recess 22a is configured to open forward, but it is also possible to configure it to open rearward.

In addition, 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 configuration of the buffer member 20 shown in the embodiment is merely an example and can be modified as appropriate within the spirit and scope of the present invention.

1 Keyboard device 2 Key 2a White key 2b Black key 4 Keyboard chassis 6 Key support mechanism 6a Key support mechanism for white keys 6b Key support mechanism for black keys 17 Upper key stopper (stopper) for black keys
18 First arm support portion 18a First support shaft (hammer support shaft)
20 Cushioning member 22 Key front side connecting portion (key side connecting portion)
22a Connection recess (engagement recess)
22b Upper wall 22c Lower wall 22d Back wall 26a Connecting recess (engagement recess)
26b Extension portion 31 First arm (hammer)
32 Second arm 35 First arm front side connecting portion (hammer side connecting portion)
35b Connecting shaft 51 Upper wall mounting portion 51b Lower surface 51c Lubricant retaining groove 52 Lower wall mounting portion 52b Upper surface 52c Lubricant retaining groove 53 Connecting portion P Virtual fulcrum of white key Q Virtual fulcrum of black key

Claims (6)

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 in conjunction with the key being pressed;
Equipped with
The key and the hammer are respectively provided with a key-side connector and a hammer-side connector, which are pivotally and slidably connected to each other, in front of the hammer spindle;
One of the key-side connecting portion and the hammer-side connecting portion has an engagement shaft extending in the left-right direction,
the other of the key-side connecting portion and the hammer-side connecting portion has a U-shaped side surface that is open 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 a buffer member is attached to the engagement recess to prevent the engagement shaft from hitting its inner circumferential surface and to make sliding contact with the engagement shaft. The buffer member is
It is made of a molded product made of elastic synthetic resin,
an upper wall mounting portion attached to the upper wall of the engagement recess so as to cover the lower surface thereof;
a lower wall mounting portion attached to a lower wall of the engagement recess so as to cover an upper surface of the lower wall;
a connecting portion that is connected to the upper wall mounting portion and the lower wall mounting portion and that is provided so as to cover the inner surface of the back wall of the engagement recess;
2. The keyboard device for a keyboard instrument according to claim 1, further comprising: 3. The keyboard device for a keyboard instrument according to claim 2, wherein the upper wall mounting portion and the lower wall mounting portion are attached to the engagement recesses with the tip ends of the upper wall and lower wall of the engagement recesses inserted therein. The engagement recess is provided on the key,
4. The keyboard device for a keyboard instrument according to claim 3, wherein one of the upper wall and the lower wall of the engagement recess protrudes forward beyond the buffer member and is configured to abut from below against a stopper that defines an upper limit position of the key when the key is released. The lower surface of the upper wall mounting portion and the upper surface of the lower wall mounting portion are configured to be parallel to each other,
5. A keyboard device for a keyboard instrument according to claim 2, wherein the engagement shaft has a circular cross section and is arranged so as to be in sliding contact with the lower surface of the upper wall mounting portion and the upper surface of the lower wall mounting portion. A keyboard device for a keyboard instrument as described in claim 5, characterized in that lubricant retaining grooves for retaining lubricant are formed on the lower surface of the upper wall mounting portion and the upper surface of the lower wall mounting portion.