Keyboard device for keyboard instrument

Abstract

Keyboard device (1) for a keyboard instrument, comprising: several keys (3), each of which extends in a front / back direction and has a pivot shaft (24) extending from a rear end of the key (3) in a left / right direction, and a keyboard frame (2) having several key support parts (17) to support the keys (3) so that each of the keys (3) can pivot about an associate of the pivot shafts (24), and which is configured to hold the keys (3) in a state arranged in the left / right direction, wherein Each of the key support parts (17) comprises: a lower support section (18) to support the pivot shaft (24) of an associated button (3) from below, and a pair of left and right upper support sections (19) that are oriented and configured upright at a predetermined mutual distance in the left / right direction, to support from above a section of the rear end of the button (3) that is located above the pivot shaft (24), and wherein when the key (3) is attached to the key support part (17), the distance between the pair of upper support sections (19) is increased by the rear end of the key (3), causing the pair of upper support sections (19) to be elastically deformed to allow the rear end of the key (3) to pass through, and, after the rear part of the key (3) has passed through, the pair of upper support sections (19) returns to its original state and cooperates with the lower support section (18) to hold the rear end of the key (3) in a restrained state.

Description

Background of the invention; Field of the invention

[0001] The present invention relates to a keyboard device used for a keyboard instrument, such as an electric piano, and in particular to a key support structure to pivotally support the keys. Description of the state of the art

[0002] Traditionally, keyboard devices have been known, for example, those disclosed in the Japanese patent publications (Kokai) JP 2011-027854 A and JP 2003-330450 A, filed by the current applicant. Each of the keyboard devices disclosed in the Japanese patent publications (Kokai) JP 2011-027854 A and JP 2003-330450 A has a keyboard frame and several keys, including white keys and black keys. The keys extend in a front / back direction and are arranged in a left / right direction, with their respective rear ends pivotably supported on the keyboard frame. Furthermore, in each of the keyboard devices, the keyboard frame and each of the keys are formed by injection molding of predetermined synthetic resins.Specifically, an ABS resin is used for the keyboard frame, and an AS resin, which has a higher hardness than the ABS resin, is used for the keys to prevent the keys from being easily scratched.

[0003] In the keyboard device disclosed in the Japanese patent publication (Kokai) JP 2011-027854 A, each key and the keyboard frame are constructed as follows: The key has pivot shafts projecting outwards from its respective left and right rear ends. On the other side, the keyboard frame has a first support element, which is arc-shaped, to support the key's pivot shafts. A pivot shaft bearing element, which has a second support element that cooperates with the first support element to form a bearing for the pivot shafts, is removablely attached to the keyboard frame by screws. According to the keyboard device constructed as described above, it is possible to improve the ease of assembly during the manufacturing process and disassembly during a disposal process, while ensuring stable pivoting movement of the keys.

[0004] On the other hand, in the keyboard device disclosed in the Japanese patent publication (Kokai) JP 2003-330450 A, each key and the keyboard frame are constructed as follows: The key has an upper wall with a rear end cut into a U-shape, and left and right side walls with corresponding rear ends shaped to project downwards for the most part, and corresponding inner surfaces formed with opposing projections. On the other hand, the keyboard frame has a keyboard support element provided on a key-wise base to support each key.A left-to-right oriented engagement hole runs through the key support, designed to engage with the two projections on the rear ends of the key's side walls when inserted from opposite sides of the support. When the key is mounted on the keyboard frame, the rear end of the key is pressed against its corresponding side of the support, causing the rear end to deform elastically. This deforms the left and right side walls of the key laterally, increasing the distance between them. Then, as the key is pressed further downwards, the two projections snap into the engagement hole of the key support by the elastic return of the opposite side walls of the key's rear end to their original position.According to the keyboard device described above, it is possible to reduce manufacturing costs by decreasing the number of component parts and assembly steps, while ensuring stable pivoting movement of the keys.

[0005] However, in the case of the keyboard device disclosed in the Japanese patent publication (Kokai) JP 2011-027854 A, it is necessary to attach the pivot shaft bearing element as a separate component to the keyboard frame in order to support the associated key and to secure it with screws, which increases the number of component parts and assembly steps. Furthermore, if the pivot shaft bearing element is attached to the keyboard frame with a faulty fastening, the pivot shafts of the key become loose, which is responsible for the noise generated when the key is pressed.On the other hand, the keyboard device disclosed in the Japanese patent publication (Kokai) JP 2003-330450 A allows for a reduction in the number of component parts and assembly steps compared to the keyboard device disclosed in the Japanese patent publication (Kokai) JP 2011-027854 A. However, since the key is made of AS resin, which has a hard property due to the requirements of its aforementioned properties, there is a concern that when the key is attached to or removed from the keyboard frame, the left and right side walls of the rear end of the key are forcibly pushed laterally outwards, overcoming considerable resistance to increase the distance between them. This could result in damage, such as cracking. Furthermore, there is a concern that if the keyboard is damaged due to an impact, e.g.,During transport, when the key is pushed forward, the side walls of the key are deformed in a direction in which they move away from each other, thereby releasing the projections of the rear end from the engagement hole of the keyboard support part.

[0006] Patent documents DE 10 2010 031 565 A1, JP 2013-073099 A and JP 2000-056768 A show further keyboard devices according to the prior art. Summary of the invention

[0007] The present invention provides a keyboard device for a keyboard instrument in which it is possible to easily attach each key to a keyboard frame while ensuring a stable pivoting movement of the key without damaging the key during the fastening process.

[0008] The present invention provides a keyboard device for a keyboard instrument, comprising: several keys, each extending in a front / back direction and having a pivot shaft extending from a rear end of the key in a left / right direction, and a keyboard frame having several key support parts to support the keys, such that each of the keys can move about an associate of the pivot shafts, and configured to hold the keys in a state arranged in the left / right direction, each of the key support parts having a lower support part to support the pivot shaft of an associate of the keys from below, and a pair of left and right upper support sections oriented and configured with a predetermined distance between them in the left / right direction, and a section of the rear end of the key arranged above the pivot shaft.to support from above, comprising and wherein the pair of upper support sections is elastically deformed to allow the rear end of the key to pass between them, and, after the rear end of the key has passed through, the pair of upper support sections returns to an original state thereof and interacts with the lower support section to hold the rear end of the key in a restrained state.

[0009] With this keyboard mechanism for a keyboard instrument, each key, extending in the front / back direction, has a pivot shaft extending in the left / right direction, formed at the rear end of the key. The keys are held on the keyboard frame in a left / right oriented position and are supported by their respective key supports, allowing each key to pivot about an associated pivot shaft. Each key support supports the pivot shaft of its associated key from below through its lower support section and supports the portion of the rear end of the key located above the pivot shaft from above through its oriented left and right upper support sections.

[0010] When the key is attached to the key support, the pair of upper support sections deforms as follows: When the rear end of the key is pressed to be inserted between the upper support sections, the distance between the two upper support sections expands, allowing the rear end of the key to pass between them. Then, after the rear end of the key has passed through, the upper support sections elastically return to their original state and work together with the lower support section to hold the rear end of the key in a restrained position. This ensures that the key, supported by the key support, performs a stable pivoting motion around the pivot shaft of the rear end of the key. Furthermore, even if the keyboard mechanism receives an impact, e.g.,During transport, it is possible to prevent a problem where the rear end of the key becomes detached from the keyboard frame.

[0011] Furthermore, unlike the prior art disclosed in the Japanese patent publication (Kokai) JP 2011-027854 A, which requires separate component parts and screwing operations to attach each key to the keyboard frame, it is possible to simply ensure that the rear end of the key is supported by the key support part of the keyboard frame. This not only prevents noise from being generated due to a component fastening error, but also reduces the number of component parts and assembly steps.Furthermore, when each key is attached, unlike in the prior art disclosed in the Japanese patent publication (Kokai) JP 2003-330450 A, in which each key is attached to the keyboard frame while its rear end is elastically deformed, the upper support sections of the key support part of the keyboard frame, but not the key itself, are elastically deformed, so that the key cannot be damaged during a process of attaching the key to the keyboard frame.

[0012] Additionally, since the upper support sections of the key support, which deform elastically when the key is attached to the keyboard frame, are oriented with a left / right spacing between them and support the section of the key located above the pivot shaft, it is possible to increase the height of the upper support sections, for example, compared to the case where the pivot shaft is supported from above. This reduces the stress generated when the upper support sections deform during key attachment and thus prevents damage to the upper support sections.

[0013] Preferably, each of the pairs of upper support sections has a support surface formed to be concavely curved along a concentric circle around the pivot shaft of an associate of the keys, while the rear end of the key has a sliding surface formed to be convexly curved along a concentric circle around the pivot shaft and to be brought into sliding contact with the support surface.

[0014] In this preferred embodiment, the key is supported in the key support section of the keyboard frame in such a way that it can pivot about the pivot shaft. The lower support section supports the pivot shaft from below, while each of the two upper support sections supports the rear end of the key via its support surface in a state that is kept in contact with the sliding surface of the key. The support surface of each of the upper support sections is formed to be concavely curved along a concentric circle around the pivot shaft of an associated key, while the sliding surface of the rear end of the key is formed to be convexly curved along a concentric circle around the pivot shaft and is brought into sliding contact with the support surface of the upper support section.Therefore, it is possible to easily ensure that the button performs a smooth and stable pivoting movement around the pivot shaft.

[0015] The above and other items, features and advantages of the present invention will become more apparent from the following description, which is given in conjunction with the accompanying drawings. Brief description of the drawings Fig. Figure 1 is a perspective view of a keyboard device (for an octave section) according to an embodiment of the present invention. Fig. 2A is a top view of the keyboard device, which is located in Fig. 1 is shown. Fig. 2B is a cross-sectional view, which is on line b--b of the Fig. 2A is taken. Fig. 3A is a perspective exploded view of a keyboard frame and the keys of the keyboard device in Fig. 1. Fig. 3B is an enlarged perspective view of a section that is in Fig. 3A is circled, at the rear end of the keyboard frame. Fig. Figure 4 is a perspective view of a white key and a black key. Fig. 5A is an enlarged top view of the rear section of a key. Fig. 5B is an enlarged left-side view of the rear section of the key. Fig. 6A is a perspective view of the appearance of a hammer. Fig. 6B is a perspective exploded view of the hammer, disassembled into a hammer body and weights. Fig. 7A and Fig. 7B are views that are useful to explain a support structure for the pivoting movement of the keyboard frame key, in which: Fig. 7A is a top view showing the respective rear sections of the keyboard frame and key, and Fig. 7B is a partial side-section view showing the respective rear sections of the keyboard frame and key. Detailed description of preferred embodiments

[0016] The present invention will now be described in detail with reference to the drawings which show its preferred embodiment. Fig. 1, Fig. 2A and Fig. Figure 2B shows a keyboard device of an electric piano according to an embodiment of the present invention, which is in a state with a released key. It should be noted that Fig. 1, Fig. 2A and Fig. 2B only shows a range of one octave of the keyboard device.

[0017] As in the Fig. 1, Fig. 2A and Fig. As shown in Figure 2B, the keyboard device 1 comprises a keyboard frame 2, several keys 3 including white keys 3a and black keys 3b which are pivotably mounted on the keyboard frame 2 and arranged in the left / right direction, several hammers 4 which are pivotably mounted on the keyboard frame 2 in conjunction with the respective keys 3, and a key switch 5 for detecting the information of the keys being pressed down via the keys 3.

[0018] The keyboard frame 2 is formed as a resin-molded object, which is brought into a predetermined shape by injection molding a predetermined resin material (e.g., an ABS resin). As in Fig. As shown in Figure 3A, the keyboard frame 2 has a front part 11, a middle part 12, and a rear part 13, each extending as a whole in the left / right direction. The front part 11, the middle part 12, and the rear part 13 are connected to each other by several ribs 14, which are arranged at appropriate intervals between them in the left / right direction. It should be noted that in the following description, the front part 11, the middle part 12, and the rear part 13 of the keyboard frame 2 will each be referred to as "the frame front 11," "the frame middle 12," and "the frame back 13," respectively.

[0019] The frame front 11 serves to guide the white keys 3a. The frame front 11 has several guide parts 11a for the white keys (of which only seven are in Fig. 3A), which are erected on it and each is inserted from below into an associate of the white keys 3a to prevent lateral swinging of the white key 3a. Furthermore, the front of the frame has 11 engagement holes 11b and 11b extending vertically through it, formed on the respective left and right sides of each of the guide parts 11a of the white keys. A pair of left and right regulating parts 21a and 21b of the upper limit position, to which reference is made below, of the white keys 3a engage in the corresponding engagement holes 11b and 11b in a state in which they are inserted through them.

[0020] The frame center 12 serves to guide the black keys 3b. Similar to the frame front 11, the frame center 12 has several guide parts 12a for the black parts (of which only seven are in Fig. 3a), which are erected on it and each is inserted from below into an associate of the black keys 3b to prevent lateral swinging of the black key 3b. Furthermore, a hammer support part 15 is arranged at a point in front of the frame center 12 to support the hammers 4.

[0021] The hammer support part 15 has several support shafts 15a extending along a single straight line in the left / right direction, and the hammers 4 are each pivotably supported by the support shafts 15a.

[0022] Furthermore, the push-button switch 5 is attached between the hammer support part 15 and the front of the frame 11. The push-button switch 5 comprises a laterally extended printed circuit board 5a, which extends in the left / right direction, and several switch bodies 5b, each formed by a rubber switch and attached to the printed circuit board 5a in conjunction with each button 3.

[0023] The rear frame 13 serves to support the keys 3 at their rear ends so that the keys 3 can pivot in the vertical direction. As in Fig. As shown in Figure 3b, the rear of the frame 13 is provided with several partitions 16, which are formed with a predetermined distance between them in the left / right direction, so that adjacent keys 3 and 3 are separated from each other. Furthermore, a predetermined key support element 17 is formed between each pair of adjacent partitions 16, which has a laterally symmetrical shape and is configured to pivotally support an associated key 3. Specifically, the key support element 17 has left and right lower support sections 18 and 18 (of which only the left one is in Fig. 3B is shown), to support from below left and right pivot shafts 24 and 24, which are referred to below, and a pair of left and right upper support sections 19 and 19 to support from above a section of a rear end of the key 3 extending from the upper surface of the key 3 to its rear surface.

[0024] Key 3, for example, is formed by injection molding a predetermined resin material (e.g., an AS resin) into a hollow mold that extends over a predetermined length in the front / back direction and opens downwards. As in Fig. 3A and Fig. As shown in Figure 4, the white key 3a has its front end formed by the pair of left and right regulating parts 21 (21a) of the upper limit position, which extend downwards from the respective side walls of the front end of the white key 3a and each have a forward bend at their lower end. The regulating parts 21 (21a) of the upper limit position engage in the corresponding left and right engagement holes 11b and 11b of the frame front 11 in a state in which they are inserted through them. Furthermore, the white key 3a has an actuator part 22 (22a) that projects downwards and is formed at a predetermined location behind the regulating parts 21a of the upper limit position. The actuator part 22a engages in an engagement recess 34, which is referred to below, of the hammer 4 in a state in which it is received therein.On the other side, the black key 3b has a front end formed with a regulating part 21 (21b) and an actuator part 22 (22b), each having the same functions as the function of each of the regulating parts 21 of the upper limit position and the actuator part 22a of the white key 3a.

[0025] As in Fig. 4, Fig. 5A and Fig. As shown in Figure 5B, the key 3 has a rear portion including a rear body 23, which is formed to have a smaller width than the portion of the key 3 forward of it and extends in the front / back direction. The pivot shafts 24 and 24, which project outwards (i.e., to the left and right respectively), are formed on the left and right side surfaces of the rear body 23 at corresponding predetermined locations near an extreme rear end of the rear body 23. Each of the pivot shafts 24 and 24 has a lower half formed as a semicircular section 24a having a curved lower surface and a semicircular side face, and a projection 24b in the front / back direction that extends upwards from the center of the semicircular section 24a.It should be noted that the semicircular section 24a of each of the pivot shafts 24 has a groove 24c formed in its curved lower surface, so that when a lubricant, such as grease, is applied to the curved lower surface of the semicircular section 24a, the grease can be retained in it for a long time.

[0026] The rear body 23 has a rear end formed by a curved surface 25 that extends with a predetermined curvature from the upper surface of the rear body 23 to its rear surface. In side view, the curved surface 25 is convexly bent along a concentric circle around the pivot shaft 24 of the key 3. Furthermore, the rear end of the rear body 23 has a conical section 26 that is continuous with the curved surface 25 and has a lateral width that decreases progressively downwards. It should be noted that the curved surface 25 is formed with a groove 25a, which has the same function as the groove 24c of the pivot shaft 24.

[0027] As in Fig. 6A and Fig. As shown in Figure 6B, the hammer 4 comprises a hammer body 31 and two weights 32 and 333 attached to the hammer body 31. The hammer body 31 is formed as a resin-molded object, produced, for example, by injection molding a predetermined resin material (e.g., POM (polyacetal resin)) into a predetermined mold. The hammer body 31 extends over a predetermined length in the front / back direction and has a bearing section 33 formed at a predetermined location forward of the center of the hammer body 31 in the front / back direction. In side view, the bearing section 33 has a downward-facing, inverted U-shaped opening and pivotably engages the support shaft 15a of the hammer support part 15 of the keyboard frame 2. The engagement recess 34 for engagement with the actuator part 22 of the button 3 is formed in the front half of the hammer body 31 at a point in front of the bearing section 33.The engagement recess 34 is open upwards and forwards, and the lower section of the actuator part 22 of the button 3 is received in the engagement recess 34 in a state where a lower end of the actuator part 22 is held in contact with a lower surface of the engagement recess. Furthermore, several switch actuation sections 35 are formed below the engagement recess 34 in the front half of the hammer body 31 to depress the switch body 5b of the push-button switch 5.

[0028] A weight mounting part 36, forming a rear half of the hammer body 31, has two pairs of engagement projections 37 and 38, i.e., front and rear, formed on the respective left and right side surfaces of the weight mounting part at predetermined locations, projecting outwards from the weight mounting part 36, i.e., to the left and right respectively, and a mounting hole 38 formed at a location near the rear pair of engagement projections 37, extending through the weight mounting part 36 in the left / right direction. It should be noted that a cutout 36a is formed in a central section of the weight mounting part 36 to prevent screws and similar components that attach the keyboard assembly 1 to the keyboard bed 10 of an electronic piano (see Figure 1) from being forced into the cutout. Fig. 2B) attach, with the hammer 4 striking each other when the keyboard device 1 is in the key-released state.

[0029] The weights 32 are made of a material (metal, such as steel) that has a greater specific gravity than the hammer body 31 and are formed as two long and narrow plates. Each weight 32 is formed by pressing a long metal plate, having a predetermined thickness and width, into a predetermined shape. Specifically, the weight 32 is formed with two engagement holes 41 and 42 (front and rear), a mounting hole 42, and a recess 43, which correspond to the two engagement projections 37 and 37, the mounting hole 38, and the cutout 36a formed in the hammer body 31. The two weights 32 and 32 are firmly secured to the hammer body 31 by rivets 44 inserted through the mounting holes 42, 42, and 38 in a state where the weight mounting part 36 of the hammer body 31 is inserted.

[0030] One of the weights attached to each of the hammers 4 (hereinafter referred to as "the normal weight 32A") has a predetermined length and is common to all hammers 4. The other weight (hereinafter referred to as "the adjustment weight 32B") is designed to have a length equal to or less than that of the normal weight 32A. Therefore, it is possible to change the weight of the hammer 4, including both weights 32A and 32B, by adjusting the length of the adjustment weight 32B.

[0031] In the keyboard device 1, constructed as above, the movement occurs when key 3 is in the released state, which is described in Fig. 1 and Fig. As shown in Figure 2B, when the button is pressed down, it pivots downwards around the left and right pivot shafts 24 and 24 of the rear end of the button 3. In accordance with this pivoting movement of the button 3, the actuator part 22 of the button 3 pushes downwards the engagement recess 34 of the hammer 4. As a consequence, the hammer 4 pushes the associated switch bodies 5b of the button switch 5 downwards through the switch actuation sections 35, while pivoting around the support shaft 15a of the hammer support part 15 in the counterclockwise direction, as shown in Figure 2B. Fig. 2B is seen. In this case, the rear end of the hammer 4 (i.e., the rear end of the normal weight 32A) is brought from below to a stop by a hammer stopping device 13a on the rear of the frame 13, thus blocking further pivoting movement of the hammer 4. Through the above-described process of pressing down the button, a predetermined contact weight, corresponding to the weight and torque of the hammer 4, is transmitted to the button 3, and the information about pressing down the button via the button 3 is simultaneously detected by the key switch 5.

[0032] On the other hand, when the pressed button 3 is released, the hammer 4 moves pivotally in a clockwise direction, as shown in Fig. 2B is seen. In accordance with this pivoting movement of the hammer 4, the key 3 is pushed upwards by the actuator part 22 and pivots upwards. As a consequence, each of the key 3 and the hammer 4 returns to its released state, as seen in the Fig. 1 and Fig. As shown in 2B, the regulating parts 21 of the upper limit position of the front end of the key 3 are brought from below to the stop with a predetermined stopping device 20 of the keyboard frame 2, thereby blocking further pivoting movement of the key 3.

[0033] Next, a more detailed description of the keyboard device 1 according to the present invention will be given, which relates to a pivotable motion support structure of the key 3, which is built on the keyboard frame 2 by the key support parts 17. Fig. 7A and Fig. Figure 7B shows the rear frame 13 of the keyboard frame 2 and the rear end of a key 3. As in the Fig. 7A and Fig.As shown in Figure 7B, the pair of left and right upper support sections 19 and 19 of each of the key support parts 17 are oriented in the rear frame 13 with a distance between them that is smaller than the lateral width of the rear body 23 of the key 3. Each of the upper support sections 19 has a front surface formed with a support surface 19a that is concavely curved along a concentric circle around the pivot shaft of the key 3. On the other side, the key 3 has the curved surface 25 at the rear end of the rear body 3, as previously described. The curved surface 25 (sliding contact surface) is convexly curved along a concentric circle around the pivot shaft 24 of the key 3 and is in sliding contact with the support surface 19a of each of the upper support sections 19 of the key support part 17.

[0034] Furthermore, the left and right lower support sections 18 and 18 of the key support part 17 support the respective left and right pivot shafts 24 and 24 of the key 3 from below, and the left and right upper support sections 19 and 19 of the key support part 17 support the respective left and right peripheral sections of the curved surface 25 of the key 3 via the support surfaces 19a and 19a of the respective upper support sections 19 and 19 from above. Thus, when the key 3 is pressed down, the key 3 performs a stable pivoting movement about the pivot shafts 24 and 24.

[0035] When key 3 is attached to the key support part 17 of the keyboard frame 2, the rear end (the conical section 26) of key 3 is pressed down from above so that it is inserted between the left and right upper support sections 19 and 19. As a consequence, the upper support sections 19 and 19 are each pressed outwards, i.e., to the left and right, respectively, to deform elastically and thus allow the rear end of the key to pass downwards between them. After the rear end of key 3 has passed downwards, the two upper support sections 19 and 19 elastically return to their original state and work together with the left and right lower support sections 18 and 18 to hold the rear end of key 3 in a restrained position.

[0036] As described above, according to the present embodiment, the rear end of the key is pivotably supported by the key support part 17, which has the lower support sections 18 and 18 and the upper support sections 19 and 19, thus ensuring stable pivoting movement of the key 3 about the pivot shafts 24 and 24. Furthermore, unlike in the prior art, the key 3 is not elastically deformed during its attachment to the keyboard frame 2, and therefore the key 3 can be easily attached to the keyboard frame 2 without being damaged.

[0037] It should be noted that the present invention is by no means limited to the embodiment described above, but can be implemented in various ways. For example, although the left and right pivot shafts 24 and 24 of the rear end of the button 3 are formed in the present embodiment in such a way that they project from the respective left and right side surfaces of the rear body 23, it is possible to use a single pivot shaft extending in the left / right direction.

[0038] It is also self-evident to a person skilled in the art that the foregoing is a preferred embodiment of the invention and that various modifications and adaptations can be made without deviating from the inventive concept and the scope of protection.

Claims

[1] Keyboard device (1) for a keyboard instrument, comprising: several keys (3), each of which extends in a front / back direction and has a pivot shaft (24) extending from a rear end of the key (3) in a left / right direction, and a keyboard frame (2) having several key support parts (17) to support the keys (3) so that each of the keys (3) can pivot about an associate of the pivot shafts (24), and which is configured to hold the keys (3) in a state arranged in the left / right direction, wherein Each of the key support parts (17) comprises: a lower support section (18) to support the pivot shaft (24) of an associated button (3) from below, and a pair of left and right upper support sections (19) that are oriented and configured upright at a predetermined mutual distance in the left / right direction, to support from above a section of the rear end of the button (3) that is located above the pivot shaft (24), and wherein when the key (3) is attached to the key support part (17), the distance between the pair of upper support sections (19) is increased by the rear end of the key (3), causing the pair of upper support sections (19) to be elastically deformed to allow the rear end of the key (3) to pass through, and, after the rear part of the key (3) has passed through, the pair of upper support sections (19) returns to its original state and cooperates with the lower support section (18) to hold the rear end of the key (3) in a restrained state. [2] Keyboard device (1) according to claim 1, wherein each of the two upper support sections (19) has a support surface (19a) which is designed to be concavely curved along a concentric circle around the pivot shaft (24) of an associated key (3), and the rear end of the key (3) has a sliding surface (25) which is designed to be convexly curved along a concentric circle around the pivot shaft (24) and can be brought into sliding contact with the support surface (19a).

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