Method for connecting the keyboard unit and internal wall

Abstract

To provide a keyboard device and a method for connecting internal walls that can improve the appearance of the white keys. [Solution] The guide wall 25a is provided with a cutout 251a formed at the connection point with the top wall 21a, and the thickness of the guide wall 25a in the region where the cutout 251a is formed is thinner than the thickness of the guide wall 25a located below the cutout 251a (other parts of the guide wall 25a other than the cutout 251a) and the thickness of the top wall 21a. This suppresses the occurrence of sink marks at the connection point between the top wall 21a and the guide wall 25a when molding the resin white keys 2a, thereby improving the appearance of the white keys 2a.

Description

Technical Field

[0001] The present invention relates to a keyboard device, and more particularly to a keyboard device capable of improving the appearance of white keys and a method for connecting internal walls.

Background Art

[0002] For example, Patent Document 1 describes a technique for resin molding (injection molding) a white key 2a including a top wall 51 whose upper surface serves as a key pressing surface and a pair of side walls 52 that hang downward from both ends on both sides in the scale direction (left - right direction) of the top wall 51. In this technique, since the pair of side walls 52 are connected by a rib wall 55 extending in the scale direction, the rib wall 55 can restrict the tilting of the side walls 52 during the resin molding of the white key 2a.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above - mentioned conventional technology, sink marks may occur at the connection portion between the top wall 51 and the rib wall 55 or at the connection portion between the side wall 52 and the rib wall 55 during resin molding. Therefore, there is a problem that the appearance of the white key 2a is easily impaired.

[0005] The present invention has been made to solve the above - mentioned problems, and an object thereof is to provide a keyboard device capable of improving the appearance of white keys and a method for connecting internal walls.

Means for Solving the Problems

[0006] To achieve this objective, the keyboard device of the present invention comprises a resin white key whose rear end is pivotably supported, the white key comprising a narrow portion that constitutes the rear end portion of the white key, and a wide portion connected to the front end of the narrow portion and having a larger dimension in the scale direction than the narrow portion, the wide portion comprising a top wall whose upper surface is the key-pressing surface, a pair of side walls hanging down from both sides of the top wall in the scale direction, an inner wall formed inward in the scale direction from the pair of side walls, and a front wall connected to the top wall and the side walls in front of the inner wall, the inner wall comprising a weight-reducing portion formed at the connection point with the top wall or the side wall, the thickness of the weight-reducing portion being thinner than the thickness of other parts of the inner wall.

[0007] The present invention relates to a method for connecting an internal wall in a keyboard device having resin white keys whose rear end is pivotably supported, wherein the white key comprises a narrow portion that constitutes the rear end portion of the white key and a wide portion connected to the front end side of the narrow portion and having a dimension in the scale direction that is greater than that of the narrow portion, and the wide portion comprises a top wall whose upper surface is a key-pressing surface, a pair of side walls hanging down from both sides of the top wall in the scale direction, an internal wall formed inward in the scale direction from the pair of side walls, and a front wall connected to the top wall and the side walls in front of the internal wall, wherein a weight-reducing portion is formed in the internal wall at the connection portion between the internal wall and the top wall or the side wall, and the thickness of the weight-reducing portion is formed to be thinner than the thickness of other parts of the internal wall. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view of a keyboard device in one embodiment. [Figure 2] This is a perspective view of the white keys from below. [Figure 3] (a) is a partially enlarged cross-sectional view of the keyboard mechanism along the line IIIa-IIIa in Figure 1, (b) is a partially enlarged cross-sectional view of the keyboard mechanism along the line IIIb-IIIb in Figure 1, and (c) is a partially enlarged cross-sectional view of the keyboard mechanism along the line IIIc-IIIc in Figure 3(a). [Figure 4](a) is a partially enlarged cross-sectional view of the keyboard mechanism along the line IVa-IVa in Figure 3(c), (b) is a partially enlarged cross-sectional view of the keyboard mechanism along the line IVb-IVb in Figure 3(c), and (c) is a partially enlarged cross-sectional view of the keyboard mechanism along the line IVc-IVc in Figure 3(c). [Modes for carrying out the invention]

[0009] The following describes preferred embodiments with reference to the attached drawings. First, the overall configuration of the keyboard device 1 will be described with reference to Figure 1. Figure 1 is a cross-sectional view of the keyboard device 1 in one embodiment. In Figure 1, the guide portion 82 (guide part 9) of the black key 2b, which is hidden by the white key 2a, is shown with a dashed line.

[0010] Furthermore, the arrows UD, FB, and LR in Figure 1 indicate the vertical, horizontal, and horizontal directions of the keyboard device 1, respectively (the direction in which the multiple keys 2 are arranged; hereinafter referred to as the "scale direction"), and the same applies to Figures 2 and beyond. Figure 1 is a cross-sectional view of the keyboard device 1 cut by a plane perpendicular to the scale direction.

[0011] As shown in Figure 1, the keyboard device 1 is a device that constitutes a keyboard instrument (electronic piano or synthesizer) and is equipped with a plurality of keys 2 (88 in this embodiment) formed from a resin material. The keys 2 consist of a plurality of white keys 2a (52 in this embodiment) for playing diatonic notes and a plurality of black keys 2b (36 in this embodiment) for playing derived notes, and these plurality of white keys 2a and black keys 2b are arranged in the scale direction (arrows L and R direction). Hereafter, when white keys 2a and black keys 2b are not distinguished, they will be referred to as keys 2.

[0012] The keyboard device 1 includes a shelf plate 3 for supporting the keys 2, and the shelf plate 3 is formed in a flat plate shape extending in the direction of the scale using synthetic resin or steel plate. A resin chassis 4 is supported on the upper surface of the shelf plate 3. The chassis 4 is fixed to the shelf plate 3 at both ends (in the direction of arrow FB) via channel material 5, and a rotating shaft 40 is provided on the upper surface of the rear end side (arrow B side) of the chassis 4, along the direction of the scale. The rear end portion of the key 2 is rotatably (oscillated) on the rotating shaft 40, and a hammer 6 that is linked to the rotation of the key 2 is provided below the key 2.

[0013] A rotating shaft 41 is provided in the approximate center of the chassis 4 in the front-to-rear direction, and a hammer 6 is rotatably supported on this rotating shaft 41. The hammer 6 comprises a mass portion 60 (mass body) located behind the rotating shaft 41 (towards arrow B) and a pressing portion 61 located in front of the rotating shaft 41 (towards arrow F).

[0014] A receiving portion 62 that is recessed downwards is formed on the upper surface of the pressing portion 61, and a projection 20 that protrudes downwards from the lower surface of the key 2 is inserted into the receiving portion 62. When the key 2 is pressed, the tip of the projection 20 slides along the bottom surface of the receiving portion 62, causing the hammer 6 to rotate around the rotation axis 41, and this rotation of the hammer 6 lifts the mass portion 60. The reaction force accompanying this rotation of the hammer 6 provides the player with the tactile sensation of pressing the key 2.

[0015] Furthermore, a circuit board 7 with a switch 70 on its upper surface is provided below the pressing portion 61. When the key 2 is pressed, the switch 70 is pressed by the downwardly displaced pressing portion 61. The on / off state of this switch 70 detects the key 2's pressing information (note information), and a musical tone signal based on this detection result is output externally.

[0016] When key 2 is released after being pressed, key 2 (hammer 6) rotates in the reverse direction to when it was pressed, and the rotation of key 2 during both pressing and releasing is guided by the guide member 8. The guide member 8 is a metal member attached to the upper surface of the front end side (arrow F side) of the chassis 4.

[0017] The guide member 8 includes a fixing portion 80 fixed to the chassis 4, and guide portions 81 and 82 that rise upward from both front and rear ends of the fixing portion 80, and these portions 80 to 82 are integrally formed by bending a metal plate. A guide component 9 made of rubber or elastomer, which is softer (has a lower hardness) than the key 2, is attached to each of the guide portions 81 and 82.

[0018] The guide component 9 is formed in a cylindrical shape having an insertion hole 90 (see FIGS. 3(a) or 3(b)) that extends upward from its lower surface, and the guide portions 81 and 82 are inserted into the insertion hole 90. The rotation of the white key 2a is guided by the guide portion 81 located on the front end side (arrow F side) of the guide member 8, and the rotation of the black key 2b is guided by the guide portion 82 located on the rear side (arrow B side) of the guide portion 81.

[0019] Next, referring to FIGS. 1 and 2, the configuration of the guiding portion of the white key 2a by the guide portion 81 (guide component 9) will be described. FIG. 2 is a perspective view of the white key 2a viewed from below.

[0020] As shown in FIGS. 1 and 2, the white key 2a includes a narrow-width portion 2a1 that constitutes a portion on its rear end side (arrow B side), and a wide-width portion 2a2 that is connected to the front end side (the end on the arrow F side) of the narrow-width portion 2a1 and has a larger width dimension in the scale direction (arrow L-R direction) than the narrow-width portion 2a1. The narrow-width portion 2a1 is a portion adjacent to the black key 2b (see FIG. 1) in the scale direction, and the wide-width portion 2a2 is a portion located on the front side of the black key 2b. These narrow-width portion 2a1 and wide-width portion 2a2 are formed by integrally molding the following plate-like walls 21a to 28a using a resin material.

[0021] Each of the narrow-width portion 2a1 and the wide-width portion 2a2 is formed in a box shape having an opening on the lower surface side by including a top wall 21a whose upper surface serves as a key-pressing surface, and a pair of side walls 22a that hang downward from both ends in the scale direction of the top wall 21a. The front end side of the space surrounded by the top wall 21a and the side walls 22a is closed by a front wall 23a, and the boundary portion between the narrow-width portion 2a1 and the wide-width portion 2a2 in the space is partitioned by a partition wall 24a.

[0022] Inside the scale direction inside (inside the wide portion 2a2) of the pair of side walls 22a of the wide portion 2a2, a guide wall 25a (refer to the enlarged portion in FIG. 2) for guiding the rotation of the white key 2a is formed, and the guide wall 25a is provided in a pair at intervals in the scale direction. The side surfaces on the inner side in the scale direction of the pair of guide walls 25a (the surfaces where the pair of guide walls 25a face each other) are guide surfaces 250a guided by the guide portion 81, and the guide portion 81 (guide component 9) is inserted between the pair of guide surfaces 250a.

[0023] Next, referring to FIGS. 2 and 3, the detailed configuration of the guide portions of the white key 2a and the black key 2b will be described. FIG. 3(a) is a partial enlarged cross-sectional view of the keyboard device 1 along the line IIIa-IIIa in FIG. 1, FIG. 3(b) is a partial enlarged cross-sectional view of the keyboard device 1 along the line IIIb-IIIb in FIG. 1, and FIG. 3(c) is a partial enlarged cross-sectional view of the keyboard device along the line IIIc-IIIc in FIG. 3(a). In addition, in FIG. 3, only the main parts of the keyboard device 1 are shown.

[0024] As shown in FIGS. 2 and 3, the black key 2b (refer to FIG. 3(b)) is formed in a box shape having an opening on the lower surface side by including a top wall 21b whose upper surface serves as a key-pressing surface and a pair of side walls 22b that hang downward from both ends in the scale direction (arrow L-R direction) of the top wall 21b. The side surfaces on the inner side in the scale direction of the pair of side walls 22b are guide surfaces 220b guided by the guide portion 82, and the guide portion 82 (guide component 9) is inserted between the pair of guide surfaces 220b.

[0025] The distance La in the scale direction between the pair of guide walls 25a (guide surfaces 250a) of the white keys 2a (see Figure 3(a)) is the same as the distance Lb between the pair of side walls 22b (guide surfaces 220b) of the black keys 2b (see Figure 3(b)). That is, the distance La between the guide walls 25a of the white keys 2a (guide width of the white keys 2a) is narrower than the distance between the pair of side walls 22a. Therefore, compared to, for example, the case where the rotation of the white keys 2a is guided using the side walls 22a (inserting a part corresponding to the guide section 81 between the pair of side walls 22a), the guide section 81 and the guide components 9 attached to the guide section 81 can be made smaller. Thus, the manufacturing cost of the keyboard device 1 can be reduced.

[0026] Furthermore, since the guide width La for the white key 2a and the guide width Lb for the black key 2b are the same, a common guide component 9 can be attached to the guide sections 81 and 82 that guide these keys 2. This reduces the number of parts, thereby lowering the manufacturing cost of the keyboard device 1.

[0027] The upper ends of each of the pair of guide walls 25a are connected to the top wall 21a, and in this connection area (the region including the upper ends of the guide walls 25a), a weight-reducing section 251a (see enlarged portion of Figure 2 or Figure 3(a)) is formed by recessing the side surface of the guide wall 25a in a rectangular cross-section. The weight-reducing section 251a is formed in the shape of a groove extending along the front-to-back direction (the direction of connection with the top wall 21a).

[0028] In the region where the weight-reducing portion 251a is formed, the thickness of the guide wall 25a (internal wall) is formed to be thinner than the thickness of the guide wall 25a located below the weight-reducing portion 251a (other parts of the guide wall 25a other than the weight-reducing portion 251a) and the thickness of the top wall 21a. This suppresses the occurrence of sink marks at the connection point between the top wall 21a and the guide wall 25a during the molding of the resin white key 2a, thereby improving the appearance of the white key 2a.

[0029] Furthermore, the guide wall 25a is connected to a first rib wall 26a and a second rib wall 27a (see enlarged portion of Figure 2), which extend inward from the side wall 22a in the scale direction (hereinafter, the first rib wall 26a and the second rib wall 27a are collectively referred to as "each rib wall 26a, 27a"). The first rib wall 26a connects the front end of the guide wall 25a to the side wall 22a in the scale direction, and the second rib wall 27a connects the rear end of the guide wall 25a to the side wall 22a in the scale direction. By connecting the side wall 22a and the guide wall 25a with each rib wall 26a, 27a, the rigidity of the guide wall 25a can be improved, so that the rotation of the white key 2a can be stably guided by the sliding between the guide surface 250a and the guide part 81 (guide component 9).

[0030] In other words, by connecting the guide wall 25a and the side wall 22a with the rib walls 26a and 27a, the load in the scale direction acting when the guide surface 250a and the guide part 81 (guide component 9) slide can be mainly received by the rib walls 26a and 27a. Therefore, the concentration of a similar load on the hollowed-out section 251a can be suppressed, and the thickness of the hollowed-out section 251a can be reduced. By reducing the thickness of the hollowed-out section 251a, sink marks at the connection point between the top wall 21a and the guide wall 25a can be effectively suppressed.

[0031] Furthermore, the weight-reducing portion 251a is formed on the side of the guide wall 25a facing outward in the scale direction (opposite to the guide surface 250a). That is, since the weight-reducing portion 251a is not formed in the sliding region of the guide portion 81 (guide part 9) along the guide surface 250a, the guide portion 81 can slide along the planar guide surface 250a throughout the entire sliding region. Therefore, the rotation of the white keys 2a can be stably guided by the sliding between the guide surface 250a and the guide portion 81 (guide part 9).

[0032] In this embodiment, the front end of the guide wall 25a is connected to the first rib wall 26a. However, it is also possible to connect a guide wall 25a that extends forward (towards arrow F) from this connection point to the front wall 23a. With such a configuration, the rigidity of the guide wall 25a can be improved by the front wall 23a, but shrinkage during resin molding is more likely to occur at the connection point between the guide wall 25a and the front wall 23a.

[0033] In contrast, in this embodiment, the front end of the guide wall 25a is not connected to the front wall 23a (a gap is formed between the respective walls 23a and 25a) (see the enlarged portion of Figure 2). With this configuration, it is possible to reliably prevent sink marks from occurring on the front wall 23a during resin molding of the white key 2a, thereby improving the appearance of the white key 2a. Furthermore, even with a configuration that forms a gap between the guide wall 25a and the front wall 23a, the rigidity of the guide wall 25a can be ensured by the respective rib walls 26a and 27a, as both the front and rear ends of the guide wall 25a are connected to the side wall 22a via the respective rib walls 26a and 27a.

[0034] Similar to the guide wall 25a, the upper end of the first rib wall 26a is connected to the top wall 21a (see Figure 3(c)), while a gap S is formed between the second rib wall 27a and the top wall 21a. This gap S is for allowing the slide core to pass through during the mold forming of the white key 2a, but the details of the mold forming of this white key 2a will be described later.

[0035] A partition wall 28a (see enlarged portion of Figure 2 or Figure 3(c)) is connected to the upper end of the second rib wall 27a. This partition wall 28a is a wall that closes the upper part of a recess 29a formed on the side surface of the side wall 22a (wide portion 2a2). The recess 29a is a recess surrounded by the guide wall 25a and each rib wall 26a, 27a (with the guide wall 25a as the bottom surface). The partition wall 28a that closes the upper end of this recess 29a connects the upper end of the second rib wall 27a to the approximate vertical center of the first rib wall 26a in the front-rear direction (see Figure 3(c)), and also connects the approximate vertical center portion of the guide wall 25a to the side wall 22a in the scale direction (see Figure 3(a)).

[0036] By forming such a partition wall 28a, even if a gap S is formed between the second rib wall 27a and the top wall 21a, the rigidity of the guide wall 25a can be ensured by the rib walls 26a, 27a and the partition wall 28a. Therefore, the rotation of the white key 2a can be stably guided by the sliding between the guide surface 250a and the guide part 81 (guide component 9).

[0037] Next, the configuration of the guide portion of the white key 2a will be further explained with reference to Figures 3 and 4. Figure 4(a) is a partially enlarged cross-sectional view of the keyboard device 1 along the line IVa-IVa in Figure 3(c), Figure 4(b) is a partially enlarged cross-sectional view of the keyboard device 1 along the line IVb-IVb in Figure 3(c), and Figure 4(c) is a partially enlarged cross-sectional view of the keyboard device 1 along the line IVc-IVc in Figure 3(c). Note that in Figures 4(a) and 4(b), the external shapes of the guide portion 81 and the guide component 9 are schematically shown with dashed lines to simplify the drawings.

[0038] As shown in Figures 3 and 4, a weight-reducing section 260a (see Figure 3(c) or Figure 4(c)) is formed at the connection between the first rib wall 26a and the top wall 21a, and a weight-reducing section 261a (see Figure 4(a) or Figure 4(c)) is formed at the connection between the first rib wall 26a and the side wall 22a. These weight-reducing sections 260a and 261a are rectangular recesses formed on the rear surface (the surface facing the arrow B) of the first rib wall 26a. The weight-reducing section 260a is formed in the shape of a groove extending along the scale direction (arrow LR direction) (see Figure 4(c)), and the weight-reducing section 261a is formed in the shape of a groove extending along the vertical direction (see Figure 4(c)).

[0039] The inner end of the cutout portion 260a in the scale direction is connected to the front end of the cutout portion 251a of the guide wall 25a (see Figures 3(c) and 4(c)). Also, the outer end of the cutout portion 260a in the scale direction is connected to the upper end of the cutout portion 261a (see Figure 4(c)).

[0040] In the regions where the weight-reducing portions 260a and 261a are formed, the thickness of the first rib wall 26a (internal wall) is formed to be thinner than the thickness of the parts of the first rib wall 26a other than the weight-reducing portions 260a, and also thinner than the thickness of the top wall 21a and the side walls 22a. This suppresses the occurrence of sink marks at the connection points between the top wall 21a and the first rib wall 26a, and between the side walls 22a and the first rib wall 26a, during resin molding of the white keys 2a, thereby improving the appearance of the white keys 2a.

[0041] Here, in Figure 3(c), the imaginary line V shows the pressing surface (upper surface of the top wall 21a) when the white key 2a is displaced to the end position of the pressing motion. When another white key (not shown) adjacent to white key 2a is pressed, the area above the imaginary line V becomes a visible region Ra where the side surface (side wall 22a) of white key 2a is exposed (visible from the outside), while the area below the imaginary line V becomes an invisible region Rb where the side surface of white key 2a is hidden by the other pressed white key.

[0042] When the white key 2a is displaced from its initial position before being pressed to its final position, the guide portion 81 (guide part 9) constantly slides against the guide surface 250a of the guide wall 25a located in the invisible region Rb. For this reason, it is preferable to increase the rigidity of the guide wall 25a in the invisible region Rb. In addition, while it is necessary to ensure the appearance of the white key 2a in the visible region Ra, it is not particularly problematic if sink marks occur on the side surface (side wall 22a) of the white key 2a in the invisible region Rb.

[0043] Therefore, in this embodiment, the first rib wall 26a located in the visible region Ra has a cutout portion 261a formed at the connection point with the side wall 22a (see Figure 4(a)), while the first rib wall 26a located in the invisible region Rb does not have a cutout portion formed at the connection point with the side wall 22a (see Figure 4(b)).

[0044] As a result, in the visible region Ra, sink marks on the side surface of the white key 2a (side wall 22a) during resin molding can be suppressed, while in the invisible region Rb, the rigidity of the guide wall 25a can be effectively improved by the first rib wall 26a. Therefore, the appearance of the white key 2a can be improved while the rotation of the white key 2a can be stably guided by the sliding between the guide surface 250a and the guide part 81 (guide component 9).

[0045] Furthermore, the lower surface of the partition wall 28a (the upper end of the recess 29a) is located below the imaginary line V (see Figure 3(c)), and the entire recess 29a is formed in the invisible region Rb. This prevents the recess 29a from being exposed in the visible region Ra when other white keys (not shown) are pressed, thereby improving the appearance of the white key 2a.

[0046] Here, for example, when resin molding the white key 2a using a mold consisting of an upper mold and a lower mold, the direction of demolding is mainly the vertical direction of the white key 2a, and with respect to this demolding direction, the hollowed-out portion 251a of the guide wall 25a and the hollowed-out portions 260a, 261a of the first rib wall 26a become undercuts. For this reason, in this embodiment, the hollowed-out portions 251a, 260a, 261a are formed by a slide core that slides (back and forth) through the gap S between the top wall 21a and the second rib wall 27a.

[0047] When using such a slide core, if the configuration involves forming a weight-reducing portion 251a on the guide surface 250a side of the guide wall 25a, then the guide surface 250a also needs to be formed with the slide core. For example, in a configuration where a portion of the upper end of the guide surface 250a is formed by the slide core (the lower end portion of the guide surface 250a is formed by the lower mold), defects such as burrs extending in the front-to-back direction due to the parting line between the slide core and the lower mold are more likely to form on the guide surface 250a.

[0048] Furthermore, even if the entire guide surface 250a is formed by the slide core, similar defects are likely to occur at the lower end of the guide surface 250a. Moreover, in a configuration in which the guide surface 250a is formed by a slide core that slides in the front-rear direction, errors are likely to occur in the width dimension (or formation position) of the guide surface 250a in that direction.

[0049] In contrast, the weight-reducing portion 251a in this embodiment is formed on the side of the guide wall 25a opposite to the guide surface 250a, making it unnecessary to form the guide surface 250a with the slide core (the guide surface 250a can be formed with the lower die). This suppresses defects such as burrs on the guide surface 250a and errors in the width dimension of the guide surface 250a in the front-rear direction, thus enabling the guide surface 250a to be formed with high precision.

[0050] Furthermore, if the objective is to provide a weight-reducing section 260a at the connection point between the top wall 21a and the first rib wall 26a, it is possible to adopt a configuration in which the weight-reducing section 260a is provided on the front side of the first rib wall 26a (the side facing the front wall 23a), and the weight-reducing section 260a is formed by a sliding core that slides back and forth between the first rib wall 26a and the front wall 23a. However, in such a configuration, it is necessary to secure space between the first rib wall 26a and the front wall 23a for the sliding core to slide (by creating a wider gap between each of these walls 23a and 26a), and therefore the first rib wall 26a and the guide wall 25a need to be formed on the rear side (towards arrow B in Figure 3(c)).

[0051] In contrast, in this embodiment, since a weight-reducing portion 260a is formed on the rear surface of the first rib wall 26a, the weight-reducing portion 260a can be formed by a slide core that slides on the rear side of the first rib wall 26a. Therefore, compared to the case where the weight-reducing portion 260a is formed on the front surface of the first rib wall 26a, the first rib wall 26a and the guide wall 25a can be formed on the front side (arrow F side in Figure 3(c)). By forming the guide wall 25a as far forward as possible from the white key 2a, that is, at a position far from the rotation axis 40 of the white key 2a (see Figure 1), the rotation of the white key 2a can be stably guided by the sliding between the guide portion 81 (guide part 9) and the guide surface 250a.

[0052] Furthermore, in this embodiment, a gap S is formed between the top wall 21a and the second rib wall 27a. However, it is also possible to adopt a configuration in which the gap S is closed by connecting the second rib wall 27a to the top wall 21a, and the partition wall 28a is omitted (hereinafter simply referred to as the "configuration that closes the gap S"). In such a configuration that closes the gap S, the weight-reducing portions 260a and 261a of the first rib wall 26a can be formed by using a slide core that slides back and forth between the rib walls 26a and 27a.

[0053] However, in a configuration that closes the gap S, it is necessary to ensure a wide gap between each rib wall 26a, 27a in the front-to-back direction in order to secure space for the slide core to slide. If the gap between each rib wall 26a, 27a is wide, it is not possible to ensure sufficient rigidity of the guide wall 25a.

[0054] Furthermore, when closing the gap S, the sliding direction (scale direction) of the slide core that forms the weight-reducing portion 251a of the guide wall 25a and the sliding direction (front-back direction) of the slide core that forms the weight-reducing portions 260a and 261a of the first rib wall 26a are in different directions. Therefore, a problem arises in which it becomes difficult to form the weight-reducing portions 251a, 260a, and 261a.

[0055] To resolve this problem, it is conceivable to form the weight-reducing portion 251a of the guide wall 25a on the guide surface 250a side (the surface facing the back in the direction perpendicular to the plane of the paper in Figure 3(c)). However, in this configuration, the weight-reducing portion 251a of the guide wall 25a and the weight-reducing portions 260a and 261a of the first rib wall 26a would need to be formed with separate slide cores, thus complicating the mold structure.

[0056] In contrast, in this embodiment, a gap S is formed between the top wall 21a and the second rib wall 27a, and this gap S is formed in an area that overlaps with the entirety of the weight-reducing portions 260a and 261a of the first rib wall 26a when viewed in the front-rear direction (see Figure 4(c)). As a result, the weight-reducing portions 260a and 261a of the first rib wall 26a can be formed by a slide core that slides back and forth through the gap S, so unlike the configuration in which the gap S is closed as described above, there is no need to provide space between each rib wall 26a and 27a for the slide core to slide. Therefore, the distance between each rib wall 26a and 27a can be narrowed, and the rigidity of the guide wall 25a can be effectively improved by each rib wall 26a and 27a.

[0057] Furthermore, if the configuration is such that the weight-reducing portions 260a and 261a of the first rib wall 26a are formed by a slide core passing through the gap S, unlike the configuration in which the gap S is closed as described above, the die-cutting direction of the weight-reducing portion 251a of the guide wall 25a and the die-cutting direction of the weight-reducing portions 260a and 261a of the first rib wall 26a can be aligned. As a result, for example, each weight-reducing portion 251a, 260a, and 261a can be formed with a common slide core, thus simplifying the structure of the mold.

[0058] Furthermore, the gap S between the top wall 21a and the second rib wall 27a is formed to the point where its lower end reaches the invisible region Rb, and the entire second rib wall 27a is formed in the invisible region Rb. As described above, in the invisible region Rb, the rigidity of the guide wall 25a is more important than the appearance of the white keys 2a, so in this embodiment, no weight-reducing section is formed at the connection between the second rib wall 27a and the side wall 22a (see Figure 4(b)). This makes it possible to effectively increase the rigidity of the guide wall 25a with the second rib wall 27a while suppressing deterioration of the appearance of the white keys 2a.

[0059] In this embodiment, the second rib wall 27a located in the invisible region Rb is not configured to have a weight-reducing section formed on its entirety. However, a weight-reducing section may be formed on part or all of the second rib wall 27a at the connection point with the side wall 22a. Similarly, a weight-reducing section may be formed on part or all of the first rib wall 26a located in the invisible region Rb at the connection point with the side wall 22a.

[0060] Although the above-described embodiments have been explained, the present invention is not limited in any way to the above embodiments, and it can be easily inferred that various improvements and modifications are possible without departing from the spirit of the present invention.

[0061] Although not explained in the above embodiment, it is preferable that the thickness of the cutouts 251a, 260a, 261a of the guide wall 25a and the first rib wall 26a be between 1 / 2 and 2 / 3 of the thickness of the wall to which it is connected (for example, the top wall 21a in the case of the cutout 251a). This helps to suppress the occurrence of sink marks in the wall to which the cutouts 251a, 260a, 261a are connected.

[0062] In the above embodiment, the guide wall 25a and the first rib wall 26a were given as examples of internal walls (walls formed inward in the scale direction from the side wall 22a) where the weight-reducing portions 251a, 260a, and 261a are formed, but the embodiment is not limited to these. For example, weight-reducing portions may be formed at the connection points between the partition wall 24a and the top wall 21a and the side wall 22a, or at the connection points between the second rib wall 27a and the partition wall 28a and the side wall 22a. Also, if the upper end of the second rib wall 27a is connected to the top wall 21a, a weight-reducing portion may be formed at that connection point.

[0063] Furthermore, if other internal walls besides the walls 24a to 28a described in the above embodiment are formed inward in the scale direction from the side wall 22a, a weight-reducing portion may be formed at the connection between the other internal wall and the top wall 21a and the side wall 22a. If a weight-reducing portion is formed in such other internal walls, the weight-reducing portions 251a, 260a, and 261a of the guide wall 25a and the first rib wall 26a may be omitted.

[0064] Furthermore, it is preferable that the weight-reducing portion is formed over the entire connection portion with the wall to be connected (for example, from the front end to the rear end of the guide wall 25a), but it is not necessary for the weight-reducing portion to be formed in a part of such connection portion.

[0065] In the above embodiment, an example of the weight-reducing portions 251a, 260a, and 261a is shown as a configuration in which the ends of the guide wall 25a and the first rib wall 26a are recessed into a rectangular shape, but the embodiment is not limited to this. For example, the cross-sectional shape of the weight-reducing portions 251a, 260a, and 261a may be formed into a shape other than a rectangle. Also, in the case where the thickness of the internal wall (e.g., the guide wall 25a) is formed to gradually decrease as it approaches the wall to be connected (e.g., the top wall 21a), the tapered portion corresponds to the weight-reducing portion.

[0066] In the above embodiment, the front and rear ends of the guide wall 25a were described as being connected to the side wall 22a by the rib walls 26a and 27a, but the invention is not limited to this. For example, one or both of the rib walls 26a and 27a may be omitted, or another wall may be connected to the guide wall 25a in addition to the rib walls 26a and 27a.

[0067] In the above embodiment, the case in which the weight-reducing portion 251a is formed on the side surface of the guide wall 25a facing outward in the scale direction (opposite to the guide surface 250a) was described, but it is not necessarily limited to this. For example, the weight-reducing portion 251a may be formed only on the guide surface 250a, or the weight-reducing portion 251a may be formed on both the guide surface 250a and the side surface opposite to the guide surface. Similarly, for the first rib wall 26a, the weight-reducing portions 260a and 261a may be formed only on the front surface of the first rib wall 26a, or the weight-reducing portions 260a and 261a may be formed on both the front and rear surfaces of the first rib wall 26a.

[0068] In the above embodiment, a case was described in which a gap is formed between the front end of the guide wall 25a and the front wall 23a, but this is not necessarily the only case. For example, one or both of the pair of guide walls 25a may be extended forward and connected to the front wall 23a, or a separate wall may be provided to connect the front wall 23a and the first rib wall 26a front to back.

[0069] In the above embodiment, a case in which a gap S is formed between the top wall 21a and the second rib wall 27a has been described, but the invention is not limited to this. For example, the gap S may be closed (the upper end of the second rib wall 27a is connected to the top wall 21a), in which case the partition wall 28a can be omitted, and the weight-reducing portions 260a and 261a of the first rib wall 26a can be formed by slide cores that slide back and forth between the rib walls 26a and 27a. [Explanation of Symbols]

[0070] 1 Keyboard device 2a white key 2a1 Narrow part 2a2 wide part 21a Ceiling wall 22a side wall 23a front wall 25a Guide wall 251a Weight reduction section 26a First rib wall (rib wall) 260a, 261a Weight reduction section 27a Second rib wall (rib wall) 2b black key 21b The Black Keys 22b Side wall of the black key 81 Guide section (white key guide) 82 Guide section (black key guide) 9 Guide parts Ra visible range Rb invisible area S Gap

Claims

1. It features white keys made of resin, with the rear end being pivotably supported. The white key comprises a narrow portion that forms the rear end of the white key, and a wide portion connected to the front end of the narrow portion, the wide portion having a larger dimension in the scale direction than the narrow portion. The wide portion comprises a top wall whose upper surface is a push-key surface, a pair of side walls hanging downward from both sides of the top wall in the scale direction, an inner wall formed inward in the scale direction from the pair of side walls, and a front wall connected to the top wall and the side walls in front of the inner wall. The inner wall is provided with a weight-reducing portion formed at the connection point with the top wall or the side wall. A keyboard device characterized in that the thickness of the weight-reducing portion is thinner than the thickness of other parts of the inner wall.

2. It is equipped with a white key guide that guides the oscillation of the aforementioned white keys, The wide portion comprises a wall that serves as the inner wall, and includes a pair of guide walls facing each other in the scale direction, with the white key guides inserted between them, and rib walls extending outward in the scale direction from each of the pair of guide walls and connected to the side wall. The keyboard device according to claim 1, characterized in that the guide wall has the weight-reducing portion formed at the connection point with the top wall.

3. The keyboard device according to claim 2, characterized in that the weight-reducing portion of the guide wall is formed on the side surface of the guide wall facing outward in the scale direction.

4. The keyboard device according to claim 2, characterized in that the rib wall has the weight-reducing portion formed at the connection point with the top wall or the side wall.

5. The keyboard device according to claim 4, characterized in that the weight-reducing portion of the rib wall is formed in a visible area that can be seen from the outside when adjacent white keys are pressed, while the weight-reducing portion is not formed in the rib wall located below the visible area.

6. The rib wall is composed of at least a first rib wall that connects the front end portion of the guide wall to the side wall, and a second rib wall that connects the guide wall to the side wall further rearward than the first rib wall. The keyboard device according to claim 2, characterized in that the guide wall is not connected to the front wall.

7. The first rib wall includes the weight-reducing portion formed at the connection point with the top wall and the side wall, The keyboard device according to claim 6, characterized in that the weight-reducing portion of the first rib wall is formed in a visible area that is visible from the outside when an adjacent white key is pressed, while the weight-reducing portion is not formed in the first rib wall located below the visible area.

8. The keyboard device according to claim 7, characterized in that the weight-reducing portion formed at the connection between the top wall and the first rib wall is formed on the rear surface of the first rib wall.

9. A gap is formed between the top wall and the upper end of the second rib wall. The keyboard device according to claim 8, characterized in that the gap is formed in a range where the entire weight-reducing portion of the first rib wall overlaps in the front-rear direction.

10. The second rib wall is formed below the visible area, The keyboard device according to claim 9, characterized in that the weight-reducing portion is not formed at the connection portion between the side wall and the second rib wall.

11. It comprises a black key whose rear end is pivotably supported, and a black key guide that guides the pivoting of the black key, The aforementioned black key comprises a top wall whose upper surface is the pressing surface, and a pair of side walls that hang downward from both sides of the top wall of the black key in the scale direction, with the black key guide inserted between them. The keyboard device according to claim 2, characterized in that the distance between the pair of guide walls is the same as the distance between the pair of side walls of the black keys.

12. The system includes guide parts that are formed to be softer than the white keys and the black keys. The keyboard device according to claim 11, characterized in that the guide component common to each of the white key guide and the black key guide is attached to each of them.

13. A keyboard device comprising resin white keys whose rear end is pivotably supported, wherein each white key comprises a narrow portion that constitutes the rear end portion of the white key, and a wide portion connected to the front end of the narrow portion and having a dimension in the scale direction that is greater than that of the narrow portion, and the wide portion comprises a top wall whose upper surface is the key-pressing surface, a pair of side walls hanging downward from both sides of the top wall in the scale direction, an internal wall formed inward in the scale direction from the pair of side walls, and a front wall connected to the top wall and the side walls in front of the internal wall, in a method for connecting the internal wall in the keyboard device, A weight-reducing portion is formed in the inner wall at the connection point between the inner wall and the top wall or the side wall. A method for connecting an internal wall, characterized in that the thickness of the weight-reducing portion is made thinner than the thickness of other parts of the internal wall.

Images