Key guide structure of keyboard instruments

Abstract

To provide a key guide structure for a keyboard instrument that can prevent side walls from collapsing during key formation, thereby preventing lateral swing of a key during key pressing, while smoothly and stably guiding the rotating key, and also easily disengaging the key and key guide during maintenance.SOLUTION: The present invention provides a key guide structure for a keyboard instrument for guiding a key 2 that rotates in accordance with key pressing, in which each of a plurality of keys 2 comprises a rib wall 55 provided inside the key 2 and extending in a left-right direction between left and right side walls 52, 52 of a white key, and two guide walls 56 provided on the left and right inside the key 2 and spaced at a predetermined distance in the left-right direction from each other and extending forward for a predetermined length from the rib walls 55. The keyboard chassis is provided with a plurality of white key guides 11a protruding upward for each key 2, which are inserted from below between the two guide walls of the corresponding key 2 and sliding against both guide walls.SELECTED DRAWING: Figure 8

Description

Technical Field

[0004] , , , , , , , ,

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[0001] The present invention relates to a key guide structure for a keyboard instrument, which is applied to a keyboard instrument such as an electronic piano and guides a key that rotates as a key is pressed.

Background Art

[0002] As a conventional key guide structure for a keyboard instrument, for example, the one described in Patent Document 1 already filed by the applicant is known. The keyboard device of an electronic piano to which this key guide structure is applied includes a plurality of keys each having an inverted U-shaped cross section extending in the front-rear direction and composed of a top wall and left and right side walls, and a keyboard chassis that holds these keys in a side-by-side state in the left-right direction and supports each key rotatably at the rear end. A key guide for guiding the rotating key is provided for each key on this keyboard chassis. Further, in this keyboard device, both the keys and the keyboard chassis are constituted by molded products made of a hard synthetic resin. Each key guide is erected below the vicinity of the front wall of the corresponding key and is formed in a plate shape having a width dimension substantially the same as the distance between the left and right side walls of the key.

[0003] In the above key guide structure, in the key-released state, the upper end portion of the key guide engages in a state of slightly entering the inside of the key. When the key is pressed from this key-released state, the key guide engages so as to deeply enter the inside of the key, and guides the rotating key while preventing the key from swaying in the left-right direction, that is, preventing the lateral movement of the key.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, since the above keys are molded from synthetic resin, shrinkage during molding can cause the left and right side walls to bend slightly inward, resulting in what is known as "collapse." Figure 11 shows an example of collapse (the part indicated by the white arrow in the figure) occurring in the front part of the white key 60 extending in the front-to-back direction (left-to-right direction in the figure). When such collapse of the side walls occurs, if the side walls and the key guide come into strong contact with each other, the friction between them increases, which may prevent the rotating key from being guided smoothly. Of course, by setting a relatively large gap between the side walls of the key and the key guide, it is possible to avoid contact between the side walls of the key and the key guide, and the increased friction that would result if they did come into contact, even if the above collapse occurs during key molding. However, in this case, the large gap between the side walls of the key and the key guide makes it easier for the key to wobble laterally when pressed, and for example, when performing a glissando during playing, adjacent keys may collide with each other, potentially generating noise.

[0006] Furthermore, in keyboard systems like the one described above, during maintenance, the keys are generally slid forward or backward relative to the keyboard chassis to remove them. However, in the conventional key guide structure described above, the key guide on the keyboard chassis side is located immediately behind the front wall of the key, making it impossible to slide the key backward. In addition, keyboard instruments generally have components such as mouthpieces that extend in the left-right direction directly in front of the keys. Therefore, in the above-mentioned keyboard system, in order to remove the keys from the keyboard chassis during maintenance, it is necessary to remove components such as mouthpieces and the entire keyboard system from the keyboard instrument, making the maintenance work very complicated and time-consuming.

[0007] The present invention was made to solve the above-mentioned problems, and aims to provide a key guide structure for a keyboard instrument that can prevent the side walls from collapsing during key molding, thereby preventing lateral movement of the key when pressed, while smoothly and stably guiding the rotating key, and also allowing for easy disengagement of the key and key guide during maintenance. [Means for solving the problem]

[0008] To achieve the above objective, the invention according to claim 1 relates to a keyboard instrument having a plurality of keys, each made of synthetic resin, formed in a hollow shape extending in the front-rear direction and open downwards, and supported on the upper part of a keyboard chassis so as to be rotatable in the vertical direction, wherein each of the plurality of keys has a rib wall provided inside the key and extending in the left-right direction between the left and right side walls, and a rib wall provided inside the key and separated from each other at a predetermined distance in the left-right direction. It is spaced apart from the left and right side walls in the left-right direction, and Rib wall front The keyboard chassis is characterized by comprising two guide walls on the left and right that extend forward for a predetermined length, and each key is provided with a plurality of key guides that protrude upward and are inserted from below between the two guide walls of the corresponding key and slide in contact with both guide walls.

[0009] In this configuration, each key has a rib wall extending horizontally between the left and right side walls. This rib wall prevents the left and right side walls from collapsing near the rib wall during key molding. In addition, each key has two guide walls on the left and right, while the keyboard chassis has a key guide that is inserted from below between the two guide walls and slides against both guide walls. The two guide walls are, It is spaced apart from the left and right side walls in the left-right direction, and The above rib wall front Because it is positioned to extend forward, unlike conventional designs, it is not affected by the collapse of the side walls during key molding, and the distance between the two guide walls can be maintained at a predetermined distance. As a result, the key guide on the keyboard chassis side engages in sliding contact with the two guide walls on the key side, preventing lateral movement when the key is pressed and allowing the rotating key to be guided smoothly and stably.

[0010] The invention according to claim 2 is characterized in that, in the key guide structure for a keyboard instrument described in claim 1, the rib wall is provided at a predetermined position in front of the key, and the two guide walls are provided at a predetermined distance from the front wall of the key.

[0011] In this configuration, a rib wall is provided at a predetermined position on the front of the key, and two guide walls are provided on the front side thereof, so that the rotating front of the key can be smoothly guided. Furthermore, since the two guide walls are provided at a predetermined distance from the front wall of the key, by setting this predetermined distance to a distance sufficient to slide the key backward and remove it from the keyboard chassis, the key can be easily removed from the keyboard chassis by sliding the key backward during maintenance of the keyboard instrument, thereby disengaging the engagement between the two guide walls on the key side and the key guide on the keyboard chassis side.

[0012] The invention according to claim 3 is characterized in that, in the key guide structure for a keyboard instrument described in claim 2, the front ends of the two guide walls are formed to curve toward opposite sides in the left-right direction.

[0013] With this configuration, when a key is removed from the keyboard chassis during maintenance of a keyboard instrument, it is reattached to the keyboard chassis as follows: First, the key is placed on top of the keyboard chassis with the key guide inserted from below, so that the key guide on the keyboard chassis side is positioned in front of both guide walls on the key side. Next, the key is slid forward, causing the key guide to be positioned between the two guide walls and engage in sliding contact with them. With the above configuration, since the front ends of the two guide walls are formed to curve in opposite directions in the left-right direction, the distance between the front ends of the two guide walls is wider in the left-right direction compared to their rear. As described above, when the key is slid forward after being placed on top of the keyboard chassis, the key guide can be easily positioned between the two guide walls, and as a result, the key can be efficiently attached to the keyboard chassis. [Brief explanation of the drawing]

[0014] [Figure 1] This is a perspective view showing a part (one octave) of the keyboard mechanism of an electronic piano to which the present invention is applied, where (a) shows the external appearance of the keyboard mechanism, and (b) shows the state with all keys except the white and black keys on the far left omitted. [Figure 2] In the keyboard device shown in FIG. 1(b), it is a perspective view showing the state where the white keys and the black keys are removed from the keyboard chassis together with their respective key support mechanisms. [Figure 3] (a) is a plan view of the keyboard device with keys other than the leftmost white and black keys omitted, and (b) is a cross-sectional view taken along line A-A. [Figure 4] It is a perspective view showing the white key and the key support mechanism, where (a) shows the state where the white key and the key support mechanism are connected, and (b) shows the state where the white key and the key support mechanism are disassembled. [Figure 5] It is a perspective view showing the black key and the key support mechanism, where (a) shows the state where the black key and the key support mechanism are connected, and (b) shows the state where the black key and the key support mechanism are disassembled. [Figure 6] It is a diagram for explaining the operation of the white key in the keyboard device, where (a) shows the key-off state and (b) shows the key-pressed state. [Figure 7] It is a diagram for explaining the operation of the black key in the keyboard device, where (a) shows the key-off state and (b) shows the key-pressed state. [Figure 8] It is a diagram for explaining the main part of the present invention, where (a) is a plan view of the white key, (b) is a cross-sectional view taken along line B-B, and (c) is a plan view of the state where the front part of the white key is horizontally cut. [Figure 9] It is a diagram for explaining the relationship between the white key and the white key guide, where (a) is a perspective view showing the state where the front end of the white key is vertically cut and the front part of the white key is looked up from below, and (b) is a diagram showing an enlarged view of the front part of the white key in FIG. 8(c). [Figure 10] It is a diagram for explaining the relationship with the white key guide when removing the white key from the keyboard chassis, where (a) shows the state where the white key guide is located between the two guide walls of the white key, and (b) shows the state where the white key guide is disengaged from the two guide walls. [Figure 11] It is a diagram for explaining the collapse of the left and right side walls during key forming.

Embodiments for Carrying Out the Invention

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

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

[0017] This keyboard device 1 includes a keyboard chassis 4, a plurality of keys 2 composed of white keys 2a and black keys 2b and arranged side by side 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, a key switch 3 for detecting key - pressing information of each key 2, and the like.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

[0045] Next, the main components of the present invention will be described with reference to Figures 8 to 10. The main component of the present invention is to provide a key guide structure that smoothly guides the white key 2a, which rotates when pressed, in the vertical direction without lateral movement.

[0046] Figure 8(a) is a plan view of the white key 2a, Figure 8(b) is a cross-sectional view along line BB, and Figure 8(c) is a plan view of the front of the white key 2a cut horizontally. Figure 9 shows the front of the white key 2a, with (a) showing its internal structure and (b) showing its relationship with the white key guide 11a. As shown in these figures, the white key 2a is equipped with a top wall 51, left and right side walls 52, 52 and a front wall 53, each having a predetermined thickness. Wooden boards 54, 54 are attached to the outer surfaces of the left and right side walls 52, 52, respectively.

[0047] Furthermore, in the hollow portion in front of the white keys 2a, a rib wall 55 is provided at a predetermined position behind the front wall 53, extending horizontally between the left and right side walls 52, 52 and hanging downward from the top wall 51 for a predetermined length. On the front side of this rib wall 55, a pair of left and right guide walls 56, 56 are provided, connected to the rib wall 55 and the top wall 51, and extending forward from the rib wall 55 for a predetermined length, separated from each other by a predetermined distance in the left-right direction (up-down direction in Figure 9(b)).

[0048] As shown in Figure 9(b), the distance between the two guide walls 56, 56 is set to be approximately the same as the width of the white key guide 11a in the left-right direction. The white key guide 11a, which is positioned inserted from below between these guide walls 56, 56, is in sliding contact with both guide walls 56, 56.

[0049] Furthermore, both guide walls 56, 56 are provided at a predetermined distance from the front wall 53, and the front ends of both guide walls 56, 56 are formed to curve in opposite directions in the left-right direction.

[0050] Figure 10 shows the relationship between the white key 2a and the white key guide 11a when removing the white key 2a from the keyboard chassis 4. When performing maintenance on a keyboard instrument, the white key 2a can be easily removed from the keyboard chassis 4 by sliding it backward (to the right in Figure 10) from the state shown in Figure (a) to the state shown in Figure (b), thereby releasing the engagement between the two guide walls 56, 56 on the white key 2a side and the key guide 11a on the keyboard chassis 4 side.

[0051] On the other hand, the white key 2a removed from the keyboard chassis 4 is attached to the keyboard chassis as follows. First, as shown in Figure 10(b), the key guide 11a on the keyboard chassis 4 side is inserted from below the white key 2a so that it is positioned in front of both guide walls 56, 56 on the white key 2a side, and the white key 2a is placed on top of the keyboard chassis 4. Next, as shown in Figure 10(a), the white key 2a is slid forward, so that the key guide 11a is positioned between both guide walls 56, 56 and engages with both guide walls 56, 56 in a sliding contact state.

[0052] When installing the white key 2a as described above, the shape of the front ends of the two guide walls 56, 56 as described above causes the distance between the front ends of the two guide walls 56, 56 to be wider in the left-right direction compared to the rear. As described above, when sliding the white key 2a forward after placing it on the top of the keyboard chassis 4, the key guide 11a can be easily positioned between the two guide walls 56, 56, and as a result, the white key 2a can be efficiently installed on the keyboard chassis 4.

[0053] As described above, according to the key guide structure of this embodiment, a rib wall 55 extending in the left-right direction between the left and right side walls 52, 52 is provided inside the white key 2a. Therefore, unlike the key 60 in Figure 11 mentioned above, it is possible to prevent the left and right side walls 52, 52 from collapsing near the rib wall 55 during the molding of the white key 2a. Furthermore, since each guide wall 56 provided inside the white key 2a is formed to extend forward from the rib wall 55, unlike conventional designs, it is not affected by the collapsing of the side walls 52 during the molding of the white key 2a. As a result, both guide walls 56, 56 can be kept in sliding contact with the key guide 11a, and as a result, the rotating white key 2a can be smoothly and stably guided while preventing lateral movement when the key is pressed.

[0054] It should be noted that the present invention is not limited to the embodiments described above and can be implemented in various forms. For example, although the embodiment described the case in which the key guide structure of the present invention is applied to the white keys 2a, it can also be applied to the black keys 2b. Furthermore, the rib walls 55 and guide walls 56 of the white keys 2a and the detailed configuration of the key guide 11a of the keyboard chassis 4 shown in the embodiment are merely examples and can be modified as appropriate within the scope of the spirit of the present invention. [Explanation of symbols]

[0055] 1 Keyboard device 2 keys 2a white key 2b black key 4-key chassis 6 Key support mechanism 11a White Key Guide 51 White Keys 52 Side walls of the white keys 53 White Key Front Wall 55 Rib wall 56 Guide Wall

Claims

1. A keyboard instrument comprising a plurality of keys, each made of synthetic resin, extending in the front-to-back direction and formed in a hollow shape that opens downwards, and supported on the upper part of a keyboard chassis so as to be rotatable in the vertical direction, wherein the key guide structure of the keyboard instrument is for guiding the keys that rotate when pressed, Each of the aforementioned multiple keys is A rib wall is provided inside the key, extending horizontally between the left and right side walls, The key is provided with two guide walls, one on the left and one on the right, which are spaced apart from each other in the left-right direction, and which are spaced apart from the left and right side walls in the left-right direction and extend forward for a predetermined length from the front surface of the rib wall, Equipped with, The keyboard chassis is provided with a plurality of key guides that protrude upward for each key and are inserted from below between the two guide walls of the corresponding key and slide in contact with both guide walls.

2. The rib wall is provided at a predetermined position in front of the key, The key guide structure for a keyboard instrument according to claim 1, characterized in that the two guide walls are provided at a predetermined distance from the front wall of the key.

3. The key guide structure for a keyboard instrument according to claim 2, characterized in that the front ends of the two guide walls are formed to curve toward opposite sides in the left-right direction.

Images