JP7598804B2 - 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, for example, the one described in Patent Document 1, which has already been filed by the applicant. This keyboard device includes a horizontal, plate-like base, a number of keys that are provided above the base and extend a predetermined length in the front-rear direction, and a number of link mechanisms that are provided on the base and support each key from below. The link mechanism includes a front connecting link bar that extends a predetermined length in the front-rear direction and has a front end that is rotatably connected to the front of the key, and a rear connecting link bar that extends a predetermined length in the front-rear direction and has a rear end that is rotatably and slidably connected to the rear end of the key. The front connecting link bar and the rear connecting link bar are supported rotatably near the center of their respective lengths, and are connected to each other rotatably and slidably. The front connecting link bar and the rear connecting link bar are both made of elongated metal plates and formed into a predetermined shape.

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

Also, a keyboard device in which the keys rotate around a virtual fulcrum located at the rear of the keys is described in Patent Document 2. This keyboard device is composed of a frame of a predetermined shape, a base end provided at the rear end of the frame, a number of keys each extending in the front-rear direction in front of the base end, and a link section provided between each key and the base end. The link section has a number of arms (two or three) each extending a predetermined length in the front-rear direction, and the front and rear ends of each arm are connected to the rear end and the front end of the base end of the key, respectively, and are molded integrally with them. In addition, the link section is set so that the position of each arm differs depending on whether the corresponding key is a white key or a black key. In other words, the link section is configured differently for white keys and black keys. The reason why the link section is configured differently for white keys and black keys is thought to be that the length of black keys is usually shorter than that of white keys, and the key pressing action of such black keys is aligned with the key pressing action of white keys.

JP 2020-52391 A (FIGS. 3 to 5) JP 2010-286694 A (FIG. 9)

The above-mentioned Patent Document 1 describes only a link mechanism for white keys, while Patent Document 2 describes a configuration in which the link parts for the white keys and the black keys are different. Therefore, for example, by making the link mechanism of Patent Document 1 into a dedicated link mechanism for the white keys and the black keys, as in Patent Document 2, it becomes possible to align the key pressing action of the black keys, which are shorter than the white keys, with the key pressing action of the white keys.

However, if the link mechanism is manufactured as a dedicated link mechanism for the white keys and for the black keys, the multiple link bars of the link mechanism must also be manufactured differently for the white keys and for the black keys, resulting in increased manufacturing costs.

The present invention has been made to solve the above problems, and aims to provide a keyboard device for a keyboard instrument that can reduce manufacturing costs while ensuring that the key pressing actions of the white and black keys are synchronized.

In order to achieve the above object, the invention according to claim 1 comprises a keyboard chassis, a plurality of keys, including white keys and black keys, arranged on the upper part of the keyboard chassis, each extending a predetermined length in the front-rear direction and aligned with each other in the left-right direction, and a plurality of key support mechanisms for white keys and black keys, each of which engages with the keyboard chassis and is aligned with each other in the left-right direction to support the corresponding key from below, and which, when a key is pressed, causes the pressed key to rotate around a virtual fulcrum located behind the rear end of the key, and the key support mechanism is configured to extend a predetermined length in the front-rear direction, engages with a first support shaft provided on the keyboard chassis so as to be able to swing, and a first arm front connecting portion forward of the first support shaft is adapted to support the corresponding key from below. The key support mechanism has a first arm that is rotatably and/or slidably connected to a front-key connector provided at the front of the corresponding key, and a second arm that is configured to extend a predetermined length in the front-rear direction and is swingably engaged with a second shaft provided on the keyboard chassis behind the first shaft, and the second arm rear connector behind the second shaft is rotatably connected to a rear-key connector provided at the rear of the corresponding key, and the second arm front connector forward of the second shaft is rotatably and/or slidably connected to a first arm rear connector behind the first shaft of the first arm, and at least one of the first arms and the second arms in the key support mechanism for white keys and black keys are configured to be the same in shape and size.

According to this configuration, a number of keys, including white and black keys, each extending a predetermined length in the front-rear direction, are arranged side-by-side on the top of the keyboard chassis. In addition, a number of key support mechanisms for white and black keys are provided on the keyboard chassis, arranged side-by-side and engaged with the keyboard chassis, and each key support mechanism supports the corresponding key from below, and when a key is pressed, the pressed key rotates around a virtual fulcrum located at the rear.

Each key support mechanism has a first arm and a second arm of the above configuration. The first arm is pivotally engaged with the first support shaft of the keyboard chassis, and the first arm front connecting portion in front of the first support shaft is pivotally and slidably connected to the key front connecting portion provided at the front of the corresponding key. On the other hand, the second arm is pivotally engaged with the second support shaft of the keyboard chassis, and the second arm rear connecting portion behind the second support shaft is pivotally connected to the key rear connecting portion provided at the rear of the corresponding key. In addition, the second arm is pivotally and slidably connected to the first arm rear connecting portion of the first arm at the front of the second support shaft. The front and rear of the key are supported from below by the key support mechanism configured in this way, so that when the front end of the key is pressed down when the key is pressed, the rear end of the key moves downward in conjunction with the front end of the key while maintaining a certain relationship with the front end of the key. In other words, when a white or black key is pressed, the entire key rotates around a virtual fulcrum at the rear.

In addition, according to the above configuration, in the key support mechanisms for the white and black keys, at least one of the first arms and the second arms are configured to have the same shape and size, so at least one of the first arms and the second arms can be made common in the key support mechanisms for the white and black keys. This makes it possible to suppress an increase in the number of types of molds required to mold the arms, for example, when the arms are made of resin molded products, and thus suppresses the manufacturing costs of the keyboard device as a whole.

The invention according to claim 2 is characterized in that in the keyboard device of the keyboard instrument described in claim 1, the black keys are arranged so that their front ends are located rearward of the front ends of the white keys, and the front-side key connecting portion is located near the front end of the key when the key is a black key, and is located at a position corresponding to the front end of the black key when the key is a white key.

According to this configuration, the front-key connecting part is provided in a position in the length direction of the key near the front end of the black key when the key is a black key, and near the front end of the black key when the key is a white key. In other words, the front-key connecting part is provided in the same position whether the key is a white key or a black key, so the first arm connected to the front-key connecting part can be made common regardless of the type of key (white key or black key).

The invention according to claim 3 is characterized in that in the keyboard device of the keyboard instrument according to claim 1 or 2, the rear key connecting portion is provided at the same position in the length direction of the key regardless of whether the key is a white key or a black key.

With this configuration, the rear key connecting part is located at the same position in the length direction of the key whether the key is a white key or a black key, so the second arm connected to the rear key connecting part can be standardized regardless of the type of key.

The invention according to claim 4 is a keyboard device for a keyboard instrument according to any one of claims 1 to 3, characterized in that the first arm extends in the front-rear direction and has an arm body made of a resin molded product, and a weight made of a material with a higher specific gravity than the arm body and attached to the rear of the arm body so as to extend rearward, and the weight attached to the first arm is selected from a plurality of types of weights with different shapes depending on whether the key to which the first arm is connected is a white key or a black key.

With this configuration, the first arm has an arm body made of a resin molded product and a weight made of a material with a higher specific gravity, so the first arm can function as a hammer to impart touch weight to the key. The weight is selected from a number of different types of weights with different shapes depending on the type of key (white key or black key) to which the first arm is connected. As a result, even if the rotation angle of the first arm when a key is pressed differs depending on the type of key, for example, by selecting an appropriate weight from a number of types of weights, it is easy to accommodate stoppers for regulating the rotation position of the first arm.

1A and 1B are perspective views showing a keyboard device according to an embodiment of the present invention with one white key and one black key attached to a keyboard chassis, where FIG. 1A shows the state when viewed from the upper right, and FIG. 1B shows the state when viewed from the upper left. 2 is a perspective view showing the keyboard device shown in FIG. 1 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 and 1B are diagrams for explaining a keyboard chassis, in which (a) is a plan view of the keyboard chassis centered on a single chassis main body, and (b) is a cross-sectional view taken along line AA in (a). 4A and 4B are perspective views showing a white key and a key support mechanism, in which FIG. 4A shows the white key and the key support mechanism connected together, and FIG. 4B 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 is an enlarged perspective view of the rear end portion of the second arm, FIG. 1B is a view of the key and the rear end portion of the second arm when viewed from below while separated from each other, and FIG. 1C is an enlarged plan view of the key and the rear portion of the second arm. FIG. 2 is a plan view of the white keys and their key support mechanisms, and the black keys and their key support mechanisms, in which the white keys and the black keys are indicated by dashed double-dashed lines. 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.

A preferred embodiment of the present invention will be described in detail below with reference to the drawings. Fig. 1 is a perspective view of an electronic piano keyboard device 1 to which the present invention is applied, showing a state in which each of the white keys 2a and black keys 2b is attached to a keyboard chassis 4, (a) showing the state as seen from the upper right, and (b) showing the state as seen from the upper left. Fig. 2 shows the keyboard device 1 shown in Fig. 1 in a state in which the white keys 2a and black keys 2b have been removed from the keyboard chassis 4 together with the key support mechanism 6a for the white keys and the key support mechanism 6b for the black keys that support them from below, respectively.

In both figures, only a portion of the keyboard chassis 4 of the keyboard device 1 is shown, specifically, two chassis bodies 4a, 4a for one octave are shown connected to each other on the left and right. In addition, a metal front rail 8 and a metal rear rail 9 extending in the left and right direction are attached to the front and rear ends, respectively, of the underside of the keyboard chassis 4, and the keyboard chassis 4 is fixed to a shelf board (not shown) of the electronic piano via these rails 8, 9.

In addition, in the following description, when there is no particular distinction between the white keys 2a and the black keys 2b, they will simply be referred to as "keys 2", and when there is no particular distinction between the key support mechanism 6a for the white keys and the key support mechanism 6b for the black keys, they will simply be referred to as "key support mechanism 6".

Figure 3 shows the keyboard chassis 4, focusing on a single chassis body 4a, with (a) being a plan view and (b) being a cross-sectional view taken along line A-A in (a). The chassis body 4a of the keyboard chassis 4 is 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 Figure 3, the front part 11, middle part 12, and rear part 13 of this chassis body 4a are all formed to extend in the left-right direction as a whole (left-right direction in Figure 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 front part 11 of the chassis is mainly for guiding the white key 2a when pressed and for regulating the upper and lower limit positions of the front end of the white key 2a. A number of white key guides 11a are arranged in a left-right direction and stand upright on the front part 11 of the chassis. Each white key 2a is inserted from below and prevents the white key 2a from swaying sideways. The white key guides 11a are formed by attaching a resin guide body 15 of a given shape (only two are shown in Figures 2 and 3(a)) to the top of a number of standing pieces 8a that are formed integrally with the front rail 8 by bending a metal plate of a given shape.

In addition, the front part 11 of the chassis has engagement holes 11b, 11b that penetrate vertically on both the left and right sides of each white key guide 11a, and the two upper limit position regulation parts 21, 21 on the left and right sides of the white key 2a, which will be described later, engage with these engagement holes 11b, 11b in a penetrating state.

The chassis front 11 is further provided at its front end with a stopper attachment portion 11c that protrudes forward and extends left-right across the entire chassis body 4a, and an upper limit stopper 16a for the white keys and a lower limit stopper 16b for the white keys are attached to the lower and upper surfaces of this stopper attachment portion 11c, respectively, so as to extend left-right. The chassis front 11 is further provided at a predetermined position behind the white key guide 11a with a stopper attachment portion 11d for the black keys that extends left-right across the entire chassis body 4a, and an upper limit stopper 17 for the black keys is attached to this stopper attachment portion 11d so as to extend left-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 flat section 12a extending in the left-right direction, and a number 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, preventing the black key 2b from swaying sideways. The black key guides 12b are constructed by attaching a resin guide body (not shown) having a predetermined width to each of a number of standing sections 12c integrally molded with the chassis body 4a.

In addition, a first arm support section 18 that supports a first arm 31 of the key support mechanism 6 is provided at the front of the chassis intermediate section 12. This first arm support section 18 has a plurality of first support shafts 18a that are provided between adjacent ribs 14, 14 so as to extend in the left-right direction, and side guide sections 18b, 18b that are provided at both ends of each first support shaft 18a. The plurality of first support shafts 18a are arranged on the same axis line that extends in the left-right direction, and the first arm 31 is supported by these first support shafts 18a so as to be able to swing freely. In addition, the side guide sections 18b, 18b at both ends of the first support shaft 18a are formed integrally with the rib 14 and protrude toward the first support shaft 18a, and the distance between the two side guide sections 18b, 18b is set to be approximately the same as the left-right width of a bearing 36 of the first arm 31, which will be described later. As a result, when the first arm 31 swings around the first support shaft 18a, the left and right sides of the first arm 31 slide against the side guides 18b, 18b, preventing lateral vibration.

In addition, 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. The 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, and side guide sections 19b, 19b provided at both ends of each second support shaft 19a. 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, the side guide sections 19b, 19b at both ends of the second support shaft 19a are formed integrally with the rib 14 and protrude toward the second support shaft 19a, and the distance between the two side guide sections 19b, 19b is set to be approximately the same as the left-right width of a bearing 41 of the second arm 32 described later. As a result, when the second arm 32 swings around the second support shaft 19a, the left and right sides of the second arm 32 slide against the side guides 19b, 19b, preventing lateral vibration.

As described above, the first support shafts 18a with which the first arms 31 of the key support mechanism 6 engage are arranged on the same axis, and similarly, the second support shafts 19a with which the second arms 32 engage are also arranged on the same axis, so that all of the first arms 31 and all of the second arms 32 of the multiple key support mechanisms 6 in the keyboard device 1 can be uniformly aligned in the left-right direction.

Although not shown in the figures, it is also possible to arrange one of the multiple first support shafts 18a and one of the multiple second support shafts 19a on the same axis, and arrange the other on a different axis depending on the type of corresponding key 2 (white key 2a and black key 2b). In this case, in the multiple key support mechanisms 6, one of all the first arms 31 and one of all the second arms 32 can be uniformly aligned in the left-right direction, and the other can be uniformly aligned in the left-right direction for each type of key 2.

Although not shown, a key switch for detecting key press information of each key 2 is provided at the bottom of the keyboard chassis 4 between the chassis front part 11 and the chassis middle part 12. This key switch is composed of a horizontally elongated printed circuit board extending in the left-right direction and multiple switch bodies made of rubber switches attached to the printed circuit board for each key 2 and pressed by the first arm 31 when the key is pressed.

The chassis rear section 13 mainly guides the key 2 in the up-down direction while preventing lateral vibration at its rear end, and regulates the upper and lower limit positions of the rear end of the first arm 31. As shown in FIG. 3, the chassis rear section 13 has a plurality of partition walls 13a spaced apart at a predetermined interval in the left-right direction to separate adjacent keys 2, 2. In addition, adjacent partition walls 13a, 13a are provided with key guide protrusions 13b, 13b that extend in the up-down direction and protrude inward on the opposing side surfaces. The distance between the two key guide protrusions 13b, 13b is set to be approximately the same as the left-right width of the rear end of the key 2. As a result, when the key 2 is pressed, its rear end is prevented from lateral vibration and smoothly guided in the up-down direction.

As shown in FIG. 3(b), stopper attachment parts 13c and 13d are provided at predetermined upper and lower positions on the rear part 13 of the chassis, and extend in the left-right direction across the entire chassis body 4a. A first arm upper limit stopper 10a and a first arm lower limit stopper 10b are provided on these upper and lower stopper attachment parts 13c and 13d, respectively. These first arm upper limit stopper 10a and first arm lower limit stopper 10b are for regulating the upper limit and lower limit positions of the rear end of the first arm 31, which functions as a hammer to impart touch weight to the key 2. Both stoppers 10a and 10b are made of, for example, urethane, have a rectangular cross section, and are provided to extend across the entire left-right direction of the keyboard chassis 4.

As shown in FIG. 3(a), the ribs 14, 14 corresponding to the side walls at both the left and right ends of the chassis main body 4a are formed in a complementary shape that is continuous in the front-rear direction when the two chassis main bodies 4a are connected to each other. Specifically, the rib 14 at the left end of the chassis main body 4a is formed in a state in which the part corresponding to the chassis middle part 12 is omitted, while the rib 14 at the right end is formed in a state in which the parts corresponding to the chassis front part 11 and the chassis rear part 13 are omitted. Therefore, by connecting the two chassis main bodies 4a to each other adjacent to each other, the connected side wall parts can be configured in the same way as the other ribs 14 without increasing the thickness in the left-right direction. This ensures stable strength and rigidity throughout the entire left-right direction of the keyboard chassis 4.

As shown in FIG. 3(a), the chassis intermediate portion 12 has an engagement recess 12d of a predetermined shape that opens to the left at the left end of the flat portion 12a, and an engagement protrusion 12e of a predetermined shape that protrudes to the right and corresponds to the engagement recess 12d at the right end of the flat portion 12a. Therefore, when connecting two chassis bodies 4a together, the engagement protrusion 12e of one chassis body 4a is fitted into the engagement recess 12d of the other chassis body 4a, making it easy to position the two chassis bodies 4a when connecting them.

As shown in Figs. 3(a) and (b), the chassis body 4a of the keyboard chassis 4 configured as described above is provided with a first opening 5a that opens upward and forward, and a second opening 5b that opens upward. Through the first opening 5a, the first arm 31 of the key support mechanism 6 can be easily engaged with the first support shaft 18a from the outside, and through the second opening 5b, the second arm 32 can be easily engaged with the second support shaft 19a from the outside. In this way, the first arm 31 and the second arm 32 of the key support mechanism 6 can be easily assembled to the keyboard chassis 4, and as a result, the keyboard device 1 can be efficiently assembled.

As described above, the chassis main body 4a is integrally provided with the first support shaft 18a, the second support shaft 19a, the upright portion 12c for the black key guide 12b, the key guide protrusion 13b, the stopper mounting portions 11c, 11d, 13c, 13d, the side guide portion 18b for the first arm 31, the side guide portion 19b for the second arm 32, and the rib 14, and these can be easily obtained by a single molding operation.

In addition, in the chassis main body 4a, all of the multiple ribs 14 other than those on the side walls at both the left and right ends are configured to extend in the front-rear direction from the chassis front part 11 to the chassis rear part 13, but it is also possible to form certain ribs 14 so that some are omitted. For example, it is possible to omit ribs 14 as appropriate between the chassis front part 11 and the chassis middle part 12. This makes it possible to reduce the weight of the chassis main body 4a, and also reduces the manufacturing costs by reducing the material used to mold the chassis main body 4a.

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.

In addition, a front-key connecting part 22 that is connected to the first arm 31 of the key support mechanism 6a is provided at the front of the white key 2a at a predetermined position behind the upper limit position restricting part 21. This front-key connecting part 22 has a connecting recess 22a that is U-shaped and has an elongated hole-like side that opens forward.

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 engagement protrusions 23b, 23b that protrude coaxially from the left and right side surfaces of the connecting body part 23a. In addition, the rear of the white key 2a is formed with a tool insertion hole 24 that penetrates in the up-down direction 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 during maintenance of the keyboard device 1, as described below.

The rear end of the white key 2a is formed so that its width in the left-right direction is smaller than that of the portion in front of it, and is set to be approximately the same as the distance between the key guide protrusions 13b, 13b that face each other at the rear of the chassis 13 described above.

On the other hand, the key support mechanism 6a includes a first arm 31 and a second arm 32 that engage with each other and are connected to the front-side key connecting portion 22 and the rear-side 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 by injection molding a predetermined resin material (e.g., polyacetal). The arm body 33 extends a predetermined length in the front-rear direction, and is provided at its front end with a first arm front connecting portion 35 that connects to the front-side key connecting portion 22 of the white key 2a. The first arm front connecting portion 35 has a box portion 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 portion 35a. The connecting shaft 35b is connected to the connecting recess 22a of the front connecting part 22 of the white key 2a so as to be rotatable and slidable in the front-rear direction. A bush 35c is attached to the connecting shaft 35b to fill the gap between the outer periphery of the connecting shaft 35b and the inner surface of the connecting recess 22a.

The arm body 33 also has a U-shaped bearing 36 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 that connects to the second arm 32 at a predetermined position behind the bearing 36. 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 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.

The weight mounting portion 38, which is the rear of the arm body 33, has two mounting protrusions 38a, 38a that protrude outward at predetermined positions on both the left and right sides, and a mounting hole 38b that penetrates in the left-right direction is formed between them.

The weights 34 are made of a material (e.g., a metal such as iron) with a higher specific gravity than the arm body 33, and are composed of two elongated plate-shaped weights. Each weight 34 is formed into a predetermined shape by pressing a metal plate. Specifically, each weight 34 has two fitting holes 34a, 34a and a mounting hole 34b that correspond to the two mounting protrusions 38a, 38a and mounting hole 38b of the arm body 33, respectively. The weights 34, 34 are fixed to the arm body 33 by crimping rivets (not shown) inserted into the mounting holes 34b, 34b and 38b, with the weight mounting portion 38 of the arm body 33 sandwiched between them.

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

The rear part 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 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 is rotatably fitted into the corresponding engaging protrusion 23b of the key rear connecting part 23. The connecting arms 43, 43 are configured to bend in a state where the distance between their rear ends is widened to allow attachment and detachment of the connecting body part 23a and the engaging protrusion 23b.

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 (connecting shaft 37a) 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 rear of the black key 2b is provided with a rear key connection part 23, similar to the white key 2a, and has a tool insertion hole 24 that penetrates vertically.

On the other hand, 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 shape and size as the arm body 33 and the second arm 32 of the key support mechanism 6a for white keys. In addition, the two weights 34A and 34B on the left and right sides of the key support mechanism 6b for black keys have different rear shapes compared to the weight 34 of the key support mechanism 6a for white keys. In addition, the left weight 34A and the right weight 34B of the key support mechanism 6b have different rear shapes.

Now, referring to FIG. 6, the structure of the rear end of the second arm 32, i.e., the rear end of the two left and right connecting arm parts 43, 43, will be described in more detail. As shown in FIG. 6(a), each connecting arm part 43 is provided with a guide part 44 above the connecting hole 43a for guiding each engagement protrusion 23b of the key 2 into the connecting hole 43a. This guide part 44 has an inclined guide surface 44a that slopes downward toward the front toward the inside of the connecting arm part 43, and front and rear standing guide surfaces 44b, 44b that are provided in an upright state in front and behind the inclined guide surface 44a and facing each other. The upper ends of the front and rear standing guide surfaces 44b, 44b are formed in an arc shape.

Since the two left and right connecting arm portions 43, 43 of the second arm 32 have the guide portions 44, 44 formed as described above, when the key 2 is connected to the second arm 32, the pair of left and right engaging protrusions 23b, 23b of the key 2 are guided by the two guide portions 44, 44 of the second arm 32 into the lower connecting holes 43a, 43a, respectively. This makes it easy to connect the key 2 to the second arm 32 when assembling the keyboard device 1.

In addition, the upper surface of the two connecting arm parts 43, 43 of the second arm 32 has anti-slip parts 43b, 43b at the rear end, which protrude outward in the left-right direction by a predetermined length and prevent each engagement protrusion 23b of the key 2 from coming out of each connecting hole 43a of the second arm 32.

As shown in FIG. 6(c), when the left and right engagement protrusions 23b, 23b of the key 2 are fitted into the two connecting holes 43a, 43a of the second arm 32, the left and right slip-out prevention parts 43b, 43b are located directly below the left and right side walls of the key 2. For this reason, even if the rear end of the key 2 is shifted downward relative to the rear end of the second arm 32 due to a strong keystroke near the rear end of the key 2 when the key is pressed, the left and right side walls of the key 2 come into contact with the left and right slip-out prevention parts 43b, 43b of the second arm 32, preventing the rear end of the key 2 from shifting significantly downward. As a result, the left and right engagement protrusions 23b, 23b of the key 2 can be prevented from coming off the two connecting holes 43a, 43a of the second arm 32.

Figure 7 is a plan view of the white key 2a and its key support mechanism 6a, and the black key 2b and its key support mechanism 6b, with the white key 2a and the black key 2b indicated by two-dot chain lines. As shown in the figure, the white key 2a, the first arm 31, and the second arm 32 are arranged so that the center line extending along the length of the white key 2a (the vertical direction in Figure 7), the center line extending along the length of the first arm 31 of the key support mechanism 6a, and the center line extending along the length of the second arm 32 all coincide with the center line C1 in a plan view. The same is true for the black key 2b. In other words, the black key 2b and the first arm 31 and the second arm 32 of the key support mechanism 6b are arranged so that they coincide with each other's center line C2 in a plan view.

As described above, in the keyboard device 1, each key 2 and the first arm 31 and second arm 32 of the key support mechanism 6 that supports it are positioned so that their center lines in the longitudinal direction coincide with each other in a plan view, so that when a key is pressed, the force exerted on the key 2 can be stably and securely received by the key support mechanism 6. This makes it possible to increase the rigidity and durability of the keyboard device 1 as a whole.

As described above, in the key support mechanism 6a for white keys and the key support mechanism 6b for black keys, the arm bodies 33 of the first arms 31 and the second arms 32 are configured to be the same shape and size, so the arm bodies 33 of the first arms 31 and the second arms 32 can be standardized in the key support mechanisms 6 for white keys and black keys. This allows the number of types of molds required to manufacture the first arms 31 and the second arms 32 to be reduced, compared to when the first arms and second arms are different for each type of key 2, for example, and the manufacturing costs of the keyboard device as a whole can be reduced.

The weight 34 provided on the first arm 31 of the key support mechanism 6 can be selected from a number of different types of weights with different shapes depending on the type of key 2. As a result, even if the rotation angle of the first arm 31 when a key is pressed differs depending on the type of key 2, for example, by selecting an appropriate weight from the number of types of weights, the weight 34 of the first arm 31 can be appropriately abutted against the first arm upper limit stopper 10a when the key is pressed.

Next, we will explain the operation of the keys 2 and the key support mechanism 6 in the keyboard device 1 configured as above. Figure 8 shows the operation of the white key 2a and its key support mechanism 6a, and Figure 9 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. 8(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 rotation of the first arm 31, the front second arm 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. With the rotation of the second arm 32, the rear key connection part 23 connected via the rear second arm connection part 42 at the 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 of the key switch 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.

As described above, when the white key 2a is pressed down, the first arm 31 rotates counterclockwise, causing the weight 34 of the first arm 31 to tilt upward toward the rear as shown in FIG. 8(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.

During the above-mentioned rotation of the first arm 31 having the weight 34, the weight 34 acts on the rear of the first arm 31, and a rotating force acts on the first arm 31 and the second arm 32 so that the front end (first arm front connection part 35) and the rear end (second arm rear connection part 42) of each arm move upward. As a result, the white key 2a is strongly supported from below by the key support mechanism 6a, and therefore, when the white key 2a is pressed down, the touch weight as a reaction force against the press becomes large.

When the front end of the white key 2a is pressed down to the lowest position, it comes into contact with the 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. 8(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 that described above, and the second arm 32 also rotates in the opposite direction to that described above. As a result, the white key 2a rotates upward around the imaginary fulcrum P. Then, both upper limit position regulating parts 21, 21 of the white key 2a come into contact with the upper key 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. 9(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 when the key is released as shown in FIG. 9(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.

As described above in detail, the keyboard device 1 of this embodiment can provide the various effects described above.

In addition, when assembling the keyboard device 1, when connecting the key 2 to the first arm 31, the connecting shaft 35b of the first arm 31 is simply inserted into the connecting recess 22a of the key 2, and the connecting work between the key 2 and the first arm 31 can be easily performed. In addition, when connecting the key 2 to the second arm 32, the connecting body part 23a of the key 2 is inserted between the two connecting arm parts 43, 43 of the second arm 32, while pushing the space between the two connecting arm parts 43, 43 apart, and the two engaging protrusions 23b, 23b of the connecting body part 23a are fitted into the connecting holes 43a, 43a of the two connecting arm parts 43, 43, respectively. This makes it easy to connect the key 2 to the second arm 32. Furthermore, when connecting the first arm 31 and the second arm 32, the connection work between the first arm 31 and the second arm 32 can be easily performed by simply inserting the connecting shaft 37a of the first arm 31 into both connecting recesses 45b, 45b of the second arm 32.

The present invention is not limited to the above-described embodiment, but can be implemented in various forms. For example, in the embodiment, the key 2 and the first arm 31 and second arm 32 of the key support mechanism 6 that supports it are arranged so that their center lines extending along their respective length directions coincide with each other in a plan view. However, the present invention is not limited to this, and at least two of the key 2, the first arm 31, and the second arm 32 may be arranged so that their respective center lines coincide with each other in a plan view.

In the embodiment, in the connection structure between the key front connecting part 22 of the key 2 and the first arm front connecting part 35 of the first arm 31, the connecting recess 22a is provided on the key 2 side and the connecting shaft 35b is provided on the first arm 31 side, but the present invention is not limited to this, and the connecting shaft may be provided on the key 2 side and the connecting recess on the first arm 31 side. In addition, for the above connecting recess 22a, a U-shaped recess with a long hole-like side shape that opens forward is used, but it is also possible to use a recess that is simply formed in a long hole shape. In this case, for example, the connecting shaft 35b of the first arm 31 can be configured so that both left and right ends protrude outward, and the connecting recess 22a can be configured as a pair of left and right connecting recesses, and the left and right connecting recesses can be snapped into both ends of the connecting shaft, etc.

In addition, in the embodiment, in the connection structure between the key rear connection part 23 of the key 2 and the second arm rear connection part 42 of the second arm 32, the connection main body part 23a and the left and right engaging protrusions 23b, 23b are provided on the key 2 side, and the left and right connecting arm parts 43, 43 and connecting holes 43a, 43a are provided on the second arm 32 side, but the present invention is not limited to this, and it is also possible to provide the connecting arm part and the connecting hole on the key 2 side, and the connection main body part and the engaging protrusion on the second arm 32 side.

In the embodiment, in the connection structure between the first arm rear connection part 37 of the first arm 31 and the second arm front connection part 45 of the second arm 32, the connection shaft 37a is provided on the first arm 31 side and the connection recesses 45b, 45b are provided on the second arm 32 side, but the present invention is not limited to this, and the connection recess may be provided on the first arm 31 side and the connection shaft on the second arm 32 side. In addition, for the above-mentioned connection recess 45b, a U-shaped recess with a long hole-like side shape that opens forward is used, but it is also possible to use one that is simply formed in a long hole shape. In this case, it is possible to connect the connection recesses by snapping them into both ends of the connection shaft 37a via a pair of left and right connection pieces 45a, 45a in which long hole-like connection recesses are formed.

In addition, the connection structures between the key 2, the first arm 31, and the second arm 32 are not limited to the connection structures described above, and it is possible to adopt other connection structures between members or other appropriate connection structures as long as the required connection function (rotation and/or sliding) between the members connected to each other can be ensured.

In the embodiment, the weight 34 is provided on the first arm 31 of the key support mechanism 6, but the present invention is not limited to this, and the weight may be provided on the second arm 32 instead of the first arm 31. Furthermore, in the embodiment, the key switch for detecting key press information is configured to be pressed from above by the box portion 35a of the first arm front connecting portion 35 of the first arm 31, but the present invention is not limited to this, and the key switch may be placed within the movable range of the second arm 32 and pressed by the second arm 32.

Furthermore, the detailed configurations of the key 2 and the first arm 31 and second arm 32 of the key support mechanism 6 shown in the embodiment are merely examples 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 22 Front key connection portion 23 Rear key connection portion 26 Front key connection portion 31 for black keys First arm 32 Second arm 33 Arm body 34 of first arm Weight 35 Front first arm connection portion 37 Rear first arm connection portion 42 Rear second arm connection portion 45 Front second arm connection portion P Virtual fulcrum of white key Q Virtual black key

Claims (4)

A keyboard chassis and
A plurality of keys including white keys and black keys, each extending a predetermined length in the front-rear direction and arranged side by side in the left-right direction on an upper portion of the keyboard chassis;
a plurality of key support mechanisms for white and black keys, each of which is engaged with the keyboard chassis and arranged in a left-right arrangement to support the corresponding key from below, and which, when a key is pressed, rotates the pressed key about a virtual fulcrum 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, pivotably engaged with a first spindle provided on the keyboard chassis, and a first arm front connector located forward of the first spindle, which is rotatably and/or slidably connected to a key front connector provided on the front of the corresponding key;
a second arm configured to extend a predetermined length in a front-rear direction, pivotably engaged with a second spindle provided on the keyboard chassis rearward of the first spindle, with a second arm rear connector rearward of the second spindle rotatably connected to a key rear connector provided at the rear of the corresponding key, and a second arm front connector forward of the second spindle rotatably and/or slidably connected to a first arm rear connector rearward of the first spindle of the first arm,
1. A keyboard device for a keyboard instrument, wherein at least one of the first arms and the second arms in the key support mechanisms for white keys and black keys are configured to be identical in shape and size. The black keys are arranged such that their front ends are located rearward of the front ends of the white keys,
2. The keyboard device of a keyboard instrument according to claim 1, wherein the key front connecting portion is provided near the front end of the key when the key is a black key, and is provided at a position corresponding to the front end of the black key when the key is a white key. The keyboard device for a keyboard instrument according to claim 1 or 2, characterized in that the rear key connection part is provided at the same position in the length direction of the key whether the key is a white key or a black key. The first arm is
An arm body extending in the front-rear direction and made of a resin molded product;
a weight made of a material having a larger specific gravity than the arm body and attached to a rear portion of the arm body so as to extend rearward;
having
4. A keyboard device for a keyboard instrument as claimed in any one of claims 1 to 3, characterized in that the weight to be attached to the first arm is selected from a plurality of types of weights having different shapes depending on whether the key to which the first arm is connected is a white key or a black key.

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