JP7713845B2 - Keyboard device for keyboard instruments - Google Patents

Description

The present invention relates to a keyboard device that is applied to keyboard instruments such as electronic pianos, and operates so that when a key is pressed, it rotates around a virtual fulcrum that is located behind the rear end of the key.

A keyboard device of this type is known from the prior art, for example from Patent Document 1, which has already been filed by the applicant. This keyboard device is equipped with 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 that each extend a predetermined length in the front-rear direction, and the front end of the front connecting link bar is rotatably connected to the front part of the key, while the rear end of the rear connecting link bar is rotatably connected to the rear end of the key. In addition, each of the above connecting link bars is rotatably supported via a support pin provided near the center in the length direction, and the rear end of the front connecting link bar and the front end of the rear connecting link bar are rotatably and slidably connected to each other. More specifically, a long hole is formed in the rear end of the front connecting link bar, while a central connecting pin that is inserted into the long hole is protruded from the front end of the rear connecting link bar.

In the keyboard device configured as described above, when the front end of a key is pressed down, 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 rotates and slides along the length of the long hole of the front connecting link bar. When the front end of the key is pressed down to the lowest position, the rear end of the key is positioned approximately half the distance below the front end. This causes the key to rotate around a virtual fulcrum located to the rear, approximately the same length as the key itself. As a result, the key length is shorter than that of an acoustic grand piano, yet the same key operation as that of a grand piano can be obtained.

JP 2020-52391 A (FIGS. 3 to 5)

In the conventional keyboard device described above, each connecting link bar of the link mechanism is made of a hard material such as metal, so depending on the relationship between the diameter of the central connecting pin of the rear connecting link bar and the width dimension of the long hole of the front connecting link bar, there is a risk that the keys cannot be operated properly. In other words, if the diameter of the central connecting pin is smaller than the width dimension of the long hole and a relatively large gap is created between the central connecting pin and the side of the long hole in the width direction, the central connecting pin may hit the side of the long hole when a key is pressed, causing noise. Conversely, if there is almost no gap, the central connecting pin cannot slide smoothly through the long hole, and as a result, the touch when pressing down on a key may feel heavy. Therefore, there is room for improvement in this keyboard device.

The present invention has been made to solve the above problems, and aims to provide a keyboard device for a keyboard instrument that can prevent noise from occurring at the connection between the first arm and the second arm of the key support mechanism when a key is pressed, while ensuring smooth operation of that connection, thereby providing a good touch feeling.

In order to achieve the above object, the present invention according to claim 1 provides a keyboard comprising: a keyboard chassis, a key extending a predetermined length in the front-rear direction and arranged on an upper portion of the keyboard chassis; and a key support mechanism which engages with the keyboard chassis and is arranged to support the key from below, and which, when a key is pressed, causes the pressed key to rotate about an imaginary fulcrum located behind the rear end of the key. The key support mechanism is configured to extend a predetermined length in the front-rear direction and engages a first support shaft extending in the left-right direction provided on the keyboard chassis via a first bearing portion provided at a predetermined position so as to be swingable, and a first arm whose front end is connected to a front portion of the key so as to be rotatable and slidable, and is configured to extend a predetermined length in the front-rear direction. and a second arm which engages with a second support shaft extending in the left-right direction and provided rearward of the first support shaft via a second bearing portion provided at a predetermined position , and whose rear end is rotatably connected to the rear part of the key, and whose second arm front connecting portion forward of the second support shaft is rotatably and slidably connected to the first arm rear connecting portion rearward of the first support shaft of the first arm, one of the first arm rear connecting portion and the second arm front connecting portion has an engagement shaft extending in the left-right direction, and the other of the first arm rear connecting portion and the second arm front connecting portion has an engagement recess which engages with the engagement shaft, and a cushioning member is attached to the engagement shaft and slides against the inner surface of the engagement recess while covering its outer peripheral surface.

According to this configuration, the key, which extends a predetermined length in the front-rear direction and is arranged on the upper part of the keyboard chassis, is supported from below by the key support mechanism having the first arm and the second arm, and when the key is pressed, it rotates around a virtual fulcrum located behind the rear end of the key. In the key support mechanism, the first arm rear connecting part of the first arm and the second arm front connecting part of the second arm are connected to each other so as to be freely rotatable and slidable. One of the first arm rear connecting part and the second arm front connecting part has an engagement shaft, and the other has an engagement recess. A buffer member is attached to the engagement shaft, which slides against the inner surface of the engagement recess while covering its outer periphery. In this way, by attaching the buffer member to the engagement shaft, the engagement shaft does not directly hit the inner surface of the engagement recess, and therefore, when the key is pressed, noise generation at the connection part between the first arm and the second arm of the key support mechanism can be prevented. In addition, the cushioning member attached to the engagement shaft slides against the engagement recess, ensuring smooth operation at the connection between the first arm and the second arm, which provides a good feel when pressing the key.

The invention according to claim 2 is characterized in that in the keyboard device of the keyboard instrument described in claim 1, the engagement shaft is composed of a left protruding portion and a right protruding portion that protrude to the left and right, respectively, and the buffer member is composed of a molded product made of elastic synthetic resin, and has a left cylindrical portion formed in a cylindrical shape into which the left protruding portion fits, a right cylindrical portion formed in a cylindrical shape into which the right protruding portion fits, and a connecting portion provided to connect the right end face of the left cylindrical portion to the left end face of the right cylindrical portion.

With this configuration, the buffer member is made of a molded product made of elastic synthetic resin, so it can be manufactured relatively cheaply and easily. When attaching the buffer member to the engagement shaft, one of the left and right tubular parts of the buffer member is fitted into one of the left and right protruding parts of the engagement shaft, and the other tubular part is pulled via the connecting part while being fitted into the other protruding part. In this way, the buffer member can be attached to the engagement shaft relatively easily.

The invention according to claim 3 is characterized in that in the keyboard device of the keyboard instrument described in claim 2, the outer peripheral surfaces of the left and right cylindrical parts are formed with a lubricant holding part that is concave and opens outward and that holds a lubricant.

According to this configuration, the outer peripheral surfaces of the left and right cylindrical parts of the buffer member are provided with lubricant retaining portions formed in a concave shape, so that by applying lubricant to the buffer member attached to the engagement shaft, the lubricant can be retained for a long period of time on the outer peripheral surfaces of the left and right cylindrical parts. This ensures smooth operation for a long period of time at the connection between the first arm and the second arm by the engagement shaft and the engagement recess.

The invention according to claim 4 is characterized in that in the keyboard device of the keyboard instrument according to claim 2 or 3, at least one of the left and right cylindrical parts has a cut portion cut along its length.

According to this configuration, at least one of the left and right tubular parts of the buffer member has a cut portion cut along its length, so that the buffer member is attached to the engagement shaft as follows. For example, if only one of the left and right tubular parts has a cut portion, one of the left and right tubular parts that is not cut is fitted to one of the left and right protruding parts of the engagement shaft, and then the other cut tubular part is fitted to the other protruding part via the cut portion. As a result, compared to the buffer member that does not have the aforementioned cut portion, when attaching the buffer member that has a cut portion to the engagement shaft, it can be easily attached to the engagement shaft without pulling the buffer member. Also, if both the left and right tubular parts have cut portions, the buffer member can be attached to the engagement shaft even more easily by fitting each tubular part to the engagement shaft via the cut portion.

The invention of claim 5 is characterized in that, in a keyboard device of a keyboard instrument described in any one of claims 1 to 4, at least one of the inner surface of the engagement recess and the outer surface of the cushioning member is formed in a convex shape protruding from the inner surface of the engagement recess and/or the outer surface of the cushioning member , and is provided with a let-off convex portion for imparting a let-off touch feeling to the pressed key by temporarily obstructing the sliding of the engagement shaft within the engagement recess when the key is pressed.

According to this configuration, at least one of the inner surface of the engagement recess and the outer surface of the buffer member is provided with a let-off protrusion formed in a convex shape protruding from the inner surface of the engagement recess and/or the outer surface of the buffer member . When the engagement shaft slides inside the engagement recess when a key is pressed, the sliding is temporarily inhibited by the let-off protrusion. As a result, the pressed key generates a clicking sensation due to temporary resistance, providing a touch similar to the let-off of an acoustic piano.

1A and 1B are perspective views showing a portion (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 and black keys 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 the black keys, together with their respective key support mechanisms, have been removed from the keyboard chassis; FIG. 1A is a plan view of the keyboard device shown in FIG. 1B, and FIG. 1B 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. 5A and 5B are diagrams for explaining the operation of a white key in a keyboard device, in which FIG. 5A shows a key-released state and FIG. 5B shows a key-depressed state. 5A and 5B are diagrams for explaining the operation of a black key in a keyboard device, in which FIG. 5A shows a key-released state and FIG. 5B shows a key-depressed state. 1A and 1B are diagrams for explaining the main parts of the present invention, in which (a) shows the white key and the key support mechanism connected together, and (b) shows the state in which the connecting portion of the first arm and the second arm of the key support mechanism has been separated and the buffer member has been removed from the connecting shaft of the first arm. 5A, 5B, and 5C are enlarged views of the cushioning member, in which FIG. 5A is a perspective view, FIG. 5B is a front view, and FIG. FIG. 13 is a perspective view showing a modified example of the buffer member. 1A and 1B are diagrams showing a cushioning member for imparting a let-off touch feeling to a pressed key, in which FIG. 1A is a perspective view and FIG. 12 is a diagram showing a connection state between a connecting shaft of a first arm to which the buffer member of FIG. 11 is attached and a connecting recess of a second arm. FIG. 13 is a diagram similar to FIG. 12, in which (a) shows the key-released state and (b) shows the key-depressed state.

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

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

This keyboard device 1 is equipped with a keyboard chassis 4, a number of keys 2 consisting of white keys 2a and black keys 2b arranged in a row in the left-right direction, a key support mechanism 6 that is rotatably attached to the keyboard chassis 4 for each key 2 and supports the corresponding key 2 from below, and a key switch 3 for detecting key press information for each key 2.

The keyboard chassis 4 has a chassis body 4a made of a resin molded product of a predetermined shape, for example, by injection molding a predetermined resin material (e.g., ABS resin). As shown in FIG. 3, the front part 11, middle part 12, and rear part 13 of the chassis body 4a are all formed to extend in the left-right direction as a whole (left-right direction in FIG. 3(a)), and are integrally molded with a plurality of ribs 14 spaced apart in the left-right direction and each extending in the front-rear 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 the "chassis front part 11," the "chassis middle part 12," and the "chassis rear part 13," respectively.

The chassis front 11 is mainly for guiding the white key 2a when the key is pressed and for regulating the upper and lower limit positions of the front end. A plurality of white key guides 11a are arranged in a left-right direction on the chassis front 11, which are inserted from below for each white key 2a to prevent the white key 2a from swaying sideways. In addition, the chassis front 11 is provided with engagement holes 11b, 11b that penetrate in the vertical direction on both the left and right sides of each white key guide 11a, and two upper limit position regulating parts 21, 21 of the white key 2a, which will be described later, are engaged in a state in which they penetrate through both engagement holes 11b, 11b. Furthermore, the chassis front 11 is provided with a stopper attachment part 11c at its front end, which protrudes forward and extends in the left-right direction over the entire chassis body 4a, and a key upper limit stopper 16a and a key lower limit stopper 16b for the white key are attached to the lower and upper surfaces of the stopper attachment part 11c, respectively, so as to extend in the left-right direction. In addition, a black key stopper attachment section 11d is provided on the front of the chassis 11 at a specified position behind the white key guide 11a, and extends left and right across the entire chassis body 4a. An upper key limit stopper 17 for the black keys is attached to this stopper attachment section 11d so as to extend left and right.

The chassis intermediate section 12 mainly guides the black key 2b when the key is pressed, and also supports the first arm 31 and the second arm 32 of the key support mechanism 6a, 6b for the white and black keys so that they can swing freely. The chassis intermediate section 12 has a flat plate-like section 12a extending in the left-right direction, and a plurality of black key guides 12b standing on the flat section 12a and spaced appropriately in the left-right direction. Each black key guide 12b is inserted from below for each black key 2b to prevent the black key 2b from swinging sideways. In addition, a first arm support section 18 that supports the first arm 31 of the key support mechanism 6 is provided at the front of the chassis intermediate section 12. The 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 supported by these first support shafts 18a so that it can swing freely. Furthermore, a second arm support section 19 that supports a second arm 32 of the key support mechanism 6 is provided at the rear of the chassis intermediate section 12. This second arm support section 19 has a plurality of second support shafts 19a that are provided between adjacent ribs 14, 14 so as to 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 supported by these second support shafts 19a so as to be able to swing freely. In addition, a first arm lower limit stopper 10b that extends in the left-right direction over the entire chassis main body 4a is provided at a predetermined position of a middle rail 8 (described later) provided on the lower side of the chassis intermediate section 12.

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

The chassis rear part 13 mainly guides the key 2 in the vertical direction while preventing lateral vibration at its rear end, and regulates the upper limit position of the rear end of the first arm 31. As shown in Figures 2 and 3(a), the chassis rear part 13 has a plurality of partition walls 13a spaced apart from each other at a predetermined interval 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 in the left-right direction over the entire chassis main body 4a is provided at a predetermined position on the upper part of the chassis rear part 13. This first arm upper limit stopper 10a and the first arm lower limit stopper 10b provided on the chassis intermediate part 12 are intended to 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. In addition, a metal cover plate 15 is attached to the top of the rear part 13 of the chassis, extending left and right across the entire chassis body 4a and positioned to cover the rear end of the key 2.

As shown in Figs. 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. Through each of the first openings 5a, the first arm 31 of the key support mechanism 6 engages with the first support shaft 18a from the outside, and through each of the second openings 5b, the second arm 32 engages with the second support shaft 19a from the outside.

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

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

The front of the white key 2a is provided with a key front connecting part 22 that is connected to the first arm 31 of the key support mechanism 6a at a predetermined position behind the upper limit position restricting part 21. This key front connecting part 22 has a connecting recess 22a that is U-shaped and has an elongated hole-like side that opens forward. A key side noise suppression member 20 is attached to this connecting recess 22a so as to cover its entire inner circumferential surface, and is used to suppress noise generated when a connecting shaft 35b of the first arm 31 (described later) slides within the connecting recess 22a.

Furthermore, the rear of the white key 2a is provided with a key rear connecting part 23 that is connected to the second arm 32 of the key support mechanism 6a. This key rear connecting part 23 has a plate-shaped connecting body part 23a that hangs down from the center of the white key 2a in the left-right direction and has 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 side surfaces of the connecting body part 23a. In addition, a tool insertion hole 24 is formed in the rear of the white key 2a, which penetrates in the up-down 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, etc.

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 composed 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 at its front end is provided a first arm front connecting part 35 that connects to the key front connecting part 22 of the white key 2a. The first arm front connecting part 35 has a box part 35a formed in a box shape that opens upward and forward, and a connecting shaft 35b that is provided to extend in the left-right direction while connecting the front upper ends of the left and right side walls of the box part 35a. The connecting shaft 35b is connected to the connecting recess 22a of the key front connecting part 22 of the white key 2a so as to be freely rotatable and freely slidable in the front-rear direction.

The arm body 33 also has a U-shaped bearing 36 (first bearing) with a downwardly open side at a predetermined position immediately behind the first arm front connecting portion 35, and this bearing 36 rotatably engages with the first support shaft 18a of the keyboard chassis 4. Furthermore, the arm body 33 has a first arm rear connecting portion 37 at a predetermined position behind the bearing 36, which connects with 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 from the left and right side surfaces of the arm body 33. Both ends of this connecting shaft 37a engage with connecting recesses 45b, 45b of a second arm front connecting portion 45 of the second arm 32, which will be described later.

Two elongated plate-like 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 (e.g., a metal such as iron) with a higher specific gravity than the arm body 33, and is formed into a predetermined shape by pressing a metal plate, etc.

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. The second arm 32 is shorter than the first arm 31 and extends a predetermined length in the front-rear direction. The second arm 32 has a C-shaped bearing portion 41 (second bearing portion) near the center in the longitudinal direction, the side of which opens forward, and the bearing portion 41 rotatably engages with the second support shaft 19a of the keyboard chassis 4.

The rear of the second arm 32 is provided with a second arm rear connecting part 42 that is connected to the key rear connecting part 23 of the white key 2a. This second arm rear connecting part 42 is bifurcated and has two left and right connecting arms 43, 43 that extend parallel to each other for a predetermined length along the length of the second arm 32. A connecting hole 43a that penetrates in the left-right direction is formed at the rear end of each connecting arm 43. Between their rear ends, the connecting arms 43, 43 hold the connecting body part 23a of the key rear connecting part 23 of the white key 2a from both the left and right sides, and each connecting hole 43a fits rotatably into the corresponding engaging protrusion 23b of the key rear connecting part 23.

Furthermore, a second arm front connecting part 45 is provided at the front of the second arm 32, which is connected to the first arm rear connecting part 37 of the first arm 31. This second arm front connecting part 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 shape is an elongated hole and opens forward. The left and right connecting pieces 45a, 45a of the second arm front connecting part 45 are rotatably and slidably engaged with both ends of the connecting shaft 37a of the first arm 31 via the connecting recesses 45b, 45b.

5(a) shows the black key 2b and its key support mechanism 6b in an enlarged view, and FIG. 5(b) shows them in an exploded view. The black key 2b is formed by injection molding the same resin material as the white key 2a, and is shorter than the white key 2a, extends a predetermined length in the front-rear direction, and is hollow and open downward. The front lower end of the black key 2b is provided with a front-side connecting part 26 formed in a manner similar to the front-side connecting part 22 of the white key 2a. This front-side connecting part 26 has a connecting recess 26a whose side shape is an elongated hole and is formed in a U-shape that opens forward. In addition, the front-side connecting part 26 has an extension part 26b at the lower front end of the connecting recess 26a, which extends a predetermined length forward from the front surface of the main body of the black key 2b, and this extension part 26b functions as an upper limit position regulating part for the black key 2b. In the following explanation, the same components of the black key 2b and key support mechanism 6b as those of the white key 2a and key support mechanism 6a described above will be given the same reference numerals, and detailed explanations will be omitted.

The key support mechanism 6b that supports the black key 2b is constructed in a manner similar to the key support mechanism 6a for white keys described above. Specifically, the arm body 33 of the first arm 31 and the second arm 32 of the key support mechanism 6b are constructed to be exactly the same in shape and size as the arm body 33 and the second arm 32 of the key support mechanism 6a for white keys. The two weights 34, 34 on the left and right of the key support mechanism 6b for black keys have a different rear shape than the weight 34 of the key support mechanism 6a for white keys.

Next, the operation of the keys 2 and the key support mechanism 6 in the keyboard device 1 configured as described above will be described. Figure 6 shows the operation of the white key 2a and its key support mechanism 6a, and Figure 7 shows the operation of the black key 2b and its key support mechanism 6b.

When the front end of the white key 2a is pressed down by the player's finger in the released key state shown in FIG. 6(a), the front key connection part 22 of the white key 2a moves downward, causing the first arm 31 to rotate counterclockwise around the first support shaft 18a. In addition, with the above rotation of the first arm 31, the second arm front connection part 45, which engages with the connection shaft 37a of the first arm 31 via the connection recess 45b, moves upward. As a result, the second arm 32 rotates clockwise around the second support shaft 19a. Then, with this rotation of the second arm 32, the rear key connection part 23 connected via the second arm rear connection part 42 at its rear end is pulled down, and the rear end of the white key 2a moves downward.

When the first arm 31 rotates as described above, the box portion 35a of the first arm front connecting portion 35 moves downward, and the bottom wall of the box portion 35a presses the switch body 3b of the key switch 3 corresponding to the pressed key 2 from above. 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.

When the white key 2a is pressed down as described above, as the first arm 31 rotates counterclockwise, the weight 34 of the first arm 31 tilts upward at the rear as shown in FIG. 6(b), and the rear end abuts against the first arm upper limit stopper 10a from below. This prevents the first arm 31 from rotating any 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 against the key lower limit stopper 16b, preventing the white key 2a from being pressed down any further.

When the white key 2a is pressed as described above, it rotates around the virtual fulcrum P, which is located behind its rear end. The position of this virtual fulcrum P is set, for example, so that the distance from the front end of the white key 2a is approximately twice the length of the white key 2a itself. As a result, when the front end of the white key 2a is pressed down to the lowest position, the front end of the white key 2a is located a predetermined key stroke (e.g., 10 mm) lower, and the rear end is located approximately half the distance of the key stroke (e.g., 5 mm) lower, compared to when the key is released as shown in FIG. 6(a).

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 the above, and the second arm 32 also rotates in the opposite direction to the above. As a result, the white key 2a rotates upward around the virtual fulcrum P. Then, a specific 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 regulating parts 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.

The operation of the black key 2b when it is pressed is the same as that of the white key 2a and the 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, so that the black key 2b rotates around the virtual fulcrum Q at the rear. The position of this virtual fulcrum Q is set so that the distance from the front end of the black key 2b is about twice the length of the black key 2 itself, for example, like the virtual fulcrum P of the white key 2a described above. Therefore, when the front end of the black key 2b is pressed down to the 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 about 1/2 the distance of the key stroke, 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 the second arm 32 of the key support mechanism 6b rotate in the opposite direction, causing the black key 2b to rotate upward around the virtual fulcrum Q. Then, the extension 26b of the front-key connecting part 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 part of the present invention will be described with reference to Figures 8 to 13. The main part of the present invention is that in the first arm 31 of the key support mechanism 6, a buffer member 51 is provided on the outer peripheral surface side of the connecting shaft 37a of the first arm rear connecting part 37, which is the connecting part with the second arm 32. In the following description, the connecting shaft 37a formed integrally with the arm body 33 of the first arm 31 will be referred to as the "connecting shaft 50".

Figure 8(a) shows the white key 2a and its key support mechanism 6a, while figure 8(b) shows the key support mechanism 6a with the connecting portion of the first arm 31 and the second arm 32 separated and the buffer member 51 removed from the connecting shaft 50 of the first arm 31. As shown in figure 8(b), the connecting shaft 50 (engagement shaft) is composed of a left protrusion 50L and a right protrusion 50R that protrude to the left and right from the arm body 33 by the same predetermined length, respectively. These protrusions 50R, 50L are arranged on the same straight line extending in the left-right direction, and are formed into a circle with a predetermined diameter in cross section.

Figure 9 shows an enlarged view of the buffer member 51. The buffer member 51 is made of a molded product made of a predetermined synthetic resin (e.g., thermoplastic elastomer) having elasticity, and is formed into a cylindrical shape. It has a left tube portion 52 and a right tube portion 53 that are arranged at a predetermined interval from each other in the left-right direction and have the same shape, and a connecting portion 54 that is provided to connect these tube portions 52, 53. The left tube portion 52 and the right tube portion 53 have a length and an inner diameter that are approximately the same as the protruding length and diameter of each protruding portion 50L, 50R of the connecting shaft 50, and are formed into a thick-walled cylindrical shape with a predetermined thickness. In addition, the outer circumferential surfaces of the left tube portion 52 and the right tube portion 53 are provided with lubricant retaining portions 52a, 53a that are formed in a concave shape that opens outward.

On the other hand, the connecting portion 54 has an arc-shaped cross section that connects approximately 1/4 of the circumference of the right end face of the left tubular portion 52 and the left end face of the right tubular portion 53.

The cushioning member 51 configured as described above is attached to the connecting shaft 50 with the left tubular portion 52 fitted into the left protruding portion 50L of the connecting shaft 50 and the right tubular portion 53 fitted into the right protruding portion 50R of the connecting shaft 50. When attaching the cushioning member 51 to the connecting shaft 50, one of the left and right tubular portions 52, 53 is fitted into one of the left and right protruding portions 50L, 50R of the connecting shaft 50, and the other of the tubular portions 52, 53 is pulled via the connecting portion 54 while being fitted into the other of the protruding portions 50L, 50R. In this way, the cushioning member 51 can be attached to the connecting shaft 50 relatively easily.

As described above, according to the keyboard device 1 to which the essential parts of the present invention are applied, the cushioning member 51 is attached to the connecting shaft 50 of the first arm 31 with its outer circumferential surface covered, and the left and right cylindrical portions 52 and 53 of the cushioning member 51 slide against the inner surfaces of the connecting recesses 45b, 45b (engagement recesses) of the left and right connecting pieces 45a, 45a of the second arm 32. This prevents the connecting shaft 50 of the first arm from directly hitting the inner surfaces of the connecting recesses 45b of the second arm, thereby preventing noise from being generated at the connecting portion between the first arm 31 and the second arm 32 of the key support mechanism 6 when a key is pressed. In addition, smooth operation at the connecting portion between the first arm 31 and the second arm 32 can be ensured, which provides a good touch when a key is pressed.

In addition, the outer peripheral surfaces of the left and right cylindrical portions 52 and 53 of the buffer member 51 are provided with lubricant retaining portions 52a and 53a formed in a concave shape, so that by applying lubricant to the buffer member 51 attached to the connecting shaft 50, the lubricant can be retained for a long period of time on the outer peripheral surfaces of the left and right cylindrical portions 52 and 53. This ensures smooth operation for a long period of time at the connection between the first arm 31 and the second arm 32 by the connecting shaft 50 and the connecting recess 45b.

Figure 10 shows a modified example of the buffer member 51. As shown in the figure, this buffer member 51A differs from the buffer member 51 described above only in that a cut portion 53b is provided on the right tube portion 53. This cut portion 53b is cut along the length direction of the right tube portion 53. When attaching the buffer member 51 having such a cut portion 53b to the connecting shaft 50, the left tube portion 52 that is not cut is fitted to the left protruding portion 50L of the connecting shaft 50, and then the right tube portion 53 that is cut is fitted to the right protruding portion 50R via the cut portion 53a, specifically while widening the cut portion 53a. As a result, compared to the buffer member 51 described above, when attaching the buffer member 51A having a cut portion to the connecting shaft 50, the buffer member 51 can be easily attached to the connecting shaft 50 without pulling the buffer member 51. Note that in Figure 10, the cut portion 53b is provided only on the right tube portion 53, but a similar cut portion may also be provided on the left tube portion 52. In this case, the left and right tube portions 52, 53 can be fitted to the left and right protrusions 50L, 50R of the connecting shaft 50 through these cut portions, making it even easier to attach the buffer member 51 to the connecting shaft 50.

Figure 11 shows another modified example of the cushioning member 51, (a) being a perspective view and (b) being a right side view. This cushioning member 51B cooperates with the connecting recess 45b of the second arm 32 to give the depressed key 2 a let-off feel.

Specifically, as shown in FIG. 11, the left tubular portion 52 of the buffer member 51B has two let-off protrusions 52c, 52c provided at predetermined positions symmetrical to each other on its outer peripheral surface. Similarly, two let-off protrusions 53c, 53c are provided on the outer peripheral surface of the right tubular portion 53 of the buffer member 51B. Each let-off protrusion 52c, 53c extends over the entire length of the corresponding tubular portion 52, 53 and is formed to protrude outward (radially). Note that each let-off protrusion 52c, 53c is formed so that its periphery is recessed, thereby protruding relatively.

Figure 12 shows the connection state between the connecting shaft 50 of the first arm 31 to which the above-mentioned buffer member 51B is attached and the connecting recess 45b of the second arm 32. As shown in the figure, the connecting recess 45b of each connecting piece 45 of the second arm 32 has two let-off protrusions 45c, 45c at predetermined positions above and below on its inner surface. Each let-off protrusion 45c is formed to protrude a predetermined length from the inner surface of the connecting recess 45b.

13 is a diagram similar to FIG. 12, where (a) shows the key-released state and (b) shows the key-depressed state. As shown in FIG. 13(a), in the key-released state, the let-off protrusions 53c, 53c of the buffer member 51B are located forward of the let-off protrusions 45c, 45c of the engagement recess 45b of the second arm 32. When the key 2 is pressed from this state, as described above, the first arm 31 rotates counterclockwise and the second arm 32 rotates clockwise, causing the buffer member 51B integrated with the connecting shaft 50 to slide to the back side of the engagement recess 45b (the right side in FIG. 13). In this case, each let-off protrusion 53c of the buffer member 51B abuts against each let-off protrusion 45c of the engagement recess 45b from the front and then immediately moves backward (see FIG. 13(b)).

As described above, each of the let-off protrusions 53c of the buffer member 51B temporarily contacts each of the let-off protrusions 45c of the engagement recess 45b, temporarily preventing the connecting shaft 50 of the first arm 31 from sliding inside the engagement recess 45b of the second arm when the key is pressed. This creates a clicking sensation due to temporary resistance on the pressed key 2, providing a touch similar to the let-off of an acoustic piano.

The present invention is not limited to the above-described embodiment, but can be implemented in various forms. For example, in the embodiment, the connecting shaft 50 is provided on the first arm rear connecting portion 37 of the first arm 31, while the engaging recess 45b is provided on the second arm front connecting portion 45 of the second arm 32. However, it is also possible to reverse the positional relationship between the connecting shaft 50 and the engaging recess 45b, that is, to provide the connecting shaft on the second arm 32 and the engaging recess on the first arm 31. In this case, the engaging recess provided on the first arm 31 is configured to open rearward.

In addition, in the embodiment, the cushioning member 51B and the engagement recess 45b of the second arm 32 are provided with the let-off protrusions 52c, 53c, and 45c, but the shape and number of the let-off protrusions are not particularly limited, and as long as the touch sensation of a let-off can be imparted to the pressed key, the let-off protrusions may be provided only on either the cushioning member 51B or the engagement recess 45b of the second arm 32.

Furthermore, in the embodiment in which the essential parts of the present invention are applied, the key support mechanism 6a that supports the white key 2a has been described, but the present invention can of course also be applied to the key support mechanism 6b for the black key 2b. In addition, the detailed configuration of the cushioning member 51 shown in the embodiment is merely an example, and can be modified as appropriate within the scope of the spirit of the present invention.

REFERENCE SIGNS LIST 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 18 First arm support portion 18a First support shaft 19 Second arm support portion 19a Second support shaft 31 First arm 32 Second arm 37 First arm rear connecting portion 37a Connecting shaft 45 Second arm front connecting portion 45b Connecting recess (engagement recess)
45c Let-off convex portion 50 Connecting shaft (engagement shaft)
50L Left protruding portion 50R Right protruding portion 51 Cushioning member 51A Modified example of cushioning member 51B Modified example of cushioning member 52 Left cylindrical portion 52a Lubricant retaining portion 52c Let-off convex portion 53 Right cylindrical portion 53a Lubricant retaining portion 53b Cutting portion 53c Let-off convex portion 54 Connection portion P Virtual fulcrum of white key Q Virtual fulcrum of black key

Claims (5)

A keyboard chassis and
A key extending a predetermined length in the front-rear direction and disposed on the upper portion of the keyboard chassis;
a key support mechanism that is engaged with the keyboard chassis and supports the key from below, and that, when a key is pressed, causes the pressed key to rotate about a virtual fulcrum that is located behind the rear end of the key;
Equipped with
The key support mechanism includes:
a first arm configured to extend a predetermined length in the front-rear direction and to be pivotally engaged with a first support shaft provided on the keyboard chassis and extending in the left-right direction via a first bearing portion provided at a predetermined position , the first arm having a front end portion rotatably and slidably connected to a front portion of the key;
a second arm configured to extend a predetermined length in the front-rear direction, and swingably engaged with a second support shaft provided on the keyboard chassis rearward of the first support shaft and extending in the left-right direction via a second bearing provided at a predetermined position, the second arm having a rear end rotatably connected to the rear of the key, and a second arm front connecting portion forward of the second support shaft rotatably and slidably connected to a first arm rear connecting portion of the first arm rearward of the first support shaft;
It has
one of the first arm rear connecting portion and the second arm front connecting portion 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 has an engagement recess that engages with the engagement shaft,
1 is a perspective view of a keyboard device for a keyboard instrument according to the present invention; and The engagement shaft is composed of a left protruding portion and a right protruding portion protruding to the left and right, respectively,
The buffer member is
It is made of elastic synthetic resin moldings,
a left cylindrical portion into which the left protruding portion is fitted;
a right cylindrical portion formed in a cylindrical shape and into which the right protruding portion is fitted;
a connecting portion provided to connect a right end surface of the left cylindrical portion and a left end surface of the right cylindrical portion;
2. The keyboard device of claim 1, further comprising: The keyboard device for a keyboard instrument according to claim 2, characterized in that the outer peripheral surfaces of the left and right cylindrical portions are formed with lubricant retaining portions that are recessed and open outward and that retain lubricant. The keyboard device of a keyboard instrument according to claim 2 or 3, characterized in that at least one of the left and right cylindrical parts has a cut portion cut along its length. 5. A keyboard device for a keyboard instrument as described in any one of claims 1 to 4, characterized in that at least one of the inner surface of the engagement recess and the outer surface of the buffer member is provided with a let-off convex portion which is formed in a convex shape protruding from the inner surface of the engagement recess and/or the outer surface of the buffer member, and which temporarily obstructs the sliding of the engagement shaft within the engagement recess when a key is pressed, thereby giving the pressed key a let-off touch feeling.