Cases and keyboard instruments

Abstract

To provide a case with reduced loss of appearance due to changes in external temperature even when members of different materials are combined, and a keyboard musical instrument equipped with this case.SOLUTION: A case 200 of a keyboard instrument 10 comprises: a lower case 220 made of a first material as a resin material and long in a left-right direction LR as one direction; a plurality of reinforcement members 300 (first reinforcement members 310, second reinforcement members 320) fixed to the lower case 220 and divided and arranged in the left-right direction LR using a steel plate as a second material smaller in linear expansion coefficient than the first material; a front case 250 formed long in one direction and fixed over the plurality of reinforcement members 300; and side cases (left side case 230, right side case 240) arranged adjacent to the front case 250 and fixed to one ends of the reinforcement members 300.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a case and a keyboard instrument.

Background Art

[0002] Conventionally, cases combining members made of different materials have been disclosed. For example, Patent Document 1 discloses a keyboard instrument provided with a case in which a reinforcing member is attached across a front panel that is an extruded product of an aluminum material and a rear panel that is a sheet metal member made of an iron-based material, and an upper case is integrally provided. The front panel and the rear panel have their bent edges facing each other to form a joint surface, and the joint surfaces are surface-joined so that the panel surfaces of the front panel and the rear panel are continuously provided.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Cases of keyboard instruments and the like can enhance the design and reduce the weight by combining members made of different materials. On the other hand, different materials have different linear expansion coefficients, so due to changes in the outside air temperature, gaps may occur in the joint surfaces between members made of different materials, or the joint surfaces may be strongly compressed, causing distortion or cracks in the members. Then, the appearance of the case may be impaired.

[0005] An object of the present invention is to provide a case in which the appearance is less likely to be impaired due to changes in the outside air temperature even when members made of different materials are combined, and a keyboard instrument provided with this case.

Means for Solving the Problems

[0006] This invention For keyboard instruments The case is, Key array Extending in the direction lower part And, as stated above lower part It is fixed to a second material which has a coefficient of thermal expansion smaller than that of the first material, and the Key array Multiple reinforcing members arranged in a divided direction, and the Key array It extends in the direction and is fixed across the plurality of reinforcing members, and consists of a third material which has a different coefficient of thermal expansion from the first material and a larger coefficient of thermal expansion than the second material. front side member It is equipped with the following.

[0007] The keyboard instrument according to the present invention comprises the above-described case. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a case that reduces the deterioration of its appearance due to changes in ambient temperature, even when combining components made of different materials, and a keyboard instrument equipped with this case. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view showing a keyboard instrument according to an embodiment of the present invention. [Figure 2] This is a rear-view perspective view of the case according to an embodiment of the present invention, showing the side case, lower case, front case, and reinforcing member assembled together. [Figure 3] This is a perspective view showing the first reinforcing member of a case according to an embodiment of the present invention. [Figure 4] Figure 3 is a partially enlarged perspective view of a case according to an embodiment of the present invention, as seen from the direction of P1. [Figure 5] This is a perspective view showing a second reinforcing member of a case according to an embodiment of the present invention. [Figure 6] This is a cross-sectional view taken along line VI-VI in Figure 2 of a case according to an embodiment of the present invention. [Figure 7] This is a cross-sectional view taken along line VII-VII in Figure 2 of a case according to an embodiment of the present invention. [Figure 8]This is a cross-sectional view taken along line VIII-VIII in Figure 6 of a case according to an embodiment of the present invention. [Figure 9] This is a cross-sectional view taken along line IX-IX in Figure 7 of a case according to an embodiment of the present invention. [Figure 10] This is a perspective view of the left side portion of the case according to an embodiment of the present invention, with the left side of the case omitted. [Figure 11] This is a perspective view of the right side portion of a case according to an embodiment of the present invention, with the right side case omitted. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. The keyboard instrument 10 shown in Figure 1 comprises a full-size (88-key) keyboard 5 having multiple white keys 3 and multiple black keys 4, and a case 200. In the following description, the front of the keys in the front-to-back direction FB of the keyboard 5 will be referred to as front side F, the rear of the keys in the front-to-back direction FB will be referred to as rear side B, the left side when facing the keyboard 5 will be referred to as left side L, and the right side will be referred to as right side R. The arrangement direction of the keys on the keyboard 5 is left-to-right direction LR. Also, in the up-to-down direction UL of the keyboard instrument 10, the top will be referred to as upper side Up, and the bottom will be referred to as lower side Lo. In this embodiment, the keyboard instrument 10 is an electronic keyboard instrument, but other types of keyboard instruments 10 may also be used. Furthermore, the case 200 is not limited to the keyboard instrument 10, and may be a case 200 for other devices.

[0011] As shown in Figure 1, the case 200 includes an upper case 210, a lower case 220, a left side case 230 and a right side case 240 as side cases, and a front case 250. The upper case 210, lower case 220, and front case 250 are all elongated in one direction, the left-right direction LR. The upper case 210 has a top panel 211 and a rear panel (not shown). The left side case 230 and the right side case 240, which are roughly elongated rectangular shapes that are long in the front-rear direction FB, are positioned adjacent to the left and right ends of the upper case 210 and the front case 250, respectively. The lower case 220 is located below the upper case 210 and the side cases (left side case 230 and right side case 240).

[0012] On the front side F of the upper case 210, between the left side case 230 and the right side case 240, there is provided a keyboard arrangement portion 6 where the keyboard 5 is arranged. Between the left side case 230 and the right side case 240 on the front side F of the keyboard 5, there is provided a substantially plate-shaped front case 250 that is long in the left-right direction.

[0013] On the upper surface panel 211 of the upper case 210, there is provided a rotary knob 12 for adjusting the volume. On the left side case 230, there is provided an operation portion 14 having a pitch bender, push buttons, etc. on the upper surface. Also, on the front surface of the left side case 230, there is provided an earphone jack 18.

[0014] The connection structure of the lower case 220, the front case 250, and the front case 250 and the side cases (left side case 230, right side case 240) will be described in detail below. FIG. 2 shows a view of the state where the lower case 220, the side cases (left side case 230, right side case 240), and the front case 250 are connected and assembled by the reinforcing member 300 as seen from the rear side B. On the rear side B of the front case 250, there is provided a reinforcing member 300. The reinforcing member 300 is divided into a plurality of parts, and the front case 250 is fixed straddling the reinforcing member 300. In the present embodiment, a first reinforcing member 310 is provided on the left side L, and a second reinforcing member 320 is provided on the right side R, and they are provided in two parts. That is, in the present embodiment, the first reinforcing member 310 and the second reinforcing member 320 are the reinforcing members 300 arranged at the left-right ends of the plurality of reinforcing members 300. Also, the first reinforcing member 310 is provided longer than the second reinforcing member 320, and the reinforcing member 300 is asymmetrically divided.

[0015] The lower case 220 is formed by injection molding of a resin material which is the first material. The reinforcing member 300 (first reinforcing member 310, second reinforcing member 320) is formed by sheet metal processing of a steel plate which is the second material. The linear expansion coefficient of the second material is smaller than that of the first material. Also, the front case 250 is made of a wooden member.

[0016] As shown in Figure 3, the first reinforcing member 310 is provided in a roughly L-shape, elongated in the left-right direction (LR). The first reinforcing member 310 has a front plate 311 with a width approximately equal to that of the front case 250 in the vertical direction (UL, width direction), and a lower plate 312 that is bent from the lower edge of the front plate 311 toward the rear side (B) and is sufficiently narrower than the front plate 311. An engaging piece 311a (first projection) is provided at the right end of the front plate 311, which is bent toward the front side (F) in a tongue-like shape with the plate surface oriented in the left-right direction. The right end of the lower plate 312 protrudes further than the right end of the front plate 311.

[0017] As shown in Figure 4, two tongue-shaped engaging pieces 311b and 311c are provided near the left end L of the front plate 311. Of the two tongue-shaped engaging pieces 311b and 311c, the inner (right side R) engaging piece 311b (second projection) is provided by bending the plate surface in the vertical direction UL toward the front F. The engaging piece 311b has a roughly rectangular shape with an inclined portion 311b1 on the outside (left side L, left side case 230 side) so that the tip side is narrower. Of the two tongue-shaped engaging pieces 311b and 311c, the outer (left side L) engaging piece 311c (first projection) is provided by bending the plate surface in the horizontal direction LR toward the front F. The engaging piece 311c has a roughly rectangular shape.

[0018] The left end of the front plate 311 is provided with two vertically aligned protrusions 311d (contact protrusions) (see also Figure 10). Between the two protrusions 311d, a concave groove 311e is provided, extending from the left end L of the front plate 311 to the right end R, reinforcing the left end of the front plate 311. The front side F of the concave groove 311e is concave. In addition, a protruding piece 311f is provided above the left end L of the front plate 311 (upper side of the protrusions 311d), projecting the plate surface in the front-rear direction FB.

[0019] A fixing portion 313 is provided at the left end L of the front plate 311, which is bent to the rear B. The fixing portion 313 includes a vertical plate 313a with its surface facing left to right, an upper horizontal plate 313b bent to the right R from the upper end of the vertical plate 313a with its surface facing up UL, and a lower horizontal plate 313c bent to the left L from the lower end of the vertical plate 313a with its surface facing up UL. The vertical plate 313a is provided with a concave groove portion 313e that connects to the concave groove portion 311e of the front plate 311. A bent portion 313f is provided at the rear B of the vertical plate 313a, which is bent to the right R at approximately a right angle. The lower horizontal plate 313c is provided with a projection piece 313d that is bent upward at approximately a right angle (see also Figure 3). The projection pieces 311f and 313d have their tips bent.

[0020] The front plate 311 is provided with a plurality of (12 in this embodiment) screw holes 31-1 to 31-12 through which screw members 81 (see Figure 2) for fixing to the front case 250 are inserted. The bottom plate 312 is provided with a plurality of (10 in this embodiment) screw holes 32-1 to 32-10 through which screw members 82 for fixing to the lower case 220 are inserted. The edges of the rear side B of the bottom plate 312 corresponding to the screw holes 32-1 to 32-10 and the holes 40-1 to 40-4 described later protrude slightly from the rear side B.

[0021] At the left end L of the front plate 311, two screw holes 31-1 and 31-2 are provided, positioned above and below a concave groove 311e. On the other hand, at the right end R of the front plate 311, two screw holes 31-11 and 31-12 are provided, positioned above and below. The screw holes 31-3 to 31-10 between the screw holes 31-1, 31-2, 31-11, and 31-12 at both ends are spaced approximately equally along the longitudinal direction of the front plate 311 and are arranged alternately above and below. Of the multiple screw holes 31-1 to 31-12 provided in the front plate 311, the screw holes 31-1 and 31-2 at the left end L are round holes. The other screw holes 31-3 to 31-12 are elongated holes that are long in the left-right direction L. The shape of the elongated holes in screw holes 31-3 to 31-12 is the same.

[0022] The screw holes 32-1 to 32-10 provided in the lower plate 312 are all elongated holes that are long in the left-right direction (LR). The length of the elongated hole 32-6, located approximately in the center of the left-right direction (LR) of the front case 250 and the lower case 220, is shorter than the lengths of the other elongated holes 32-1 to 32-5 and 32-7 to 32-10.

[0023] Furthermore, four holes 40-1 to 40-4 provided in the lower plate 312 are through which pins 221 erected from the lower case 220 are inserted (see enclosed diagram Q1 in Figure 2). Hole 40-3, located approximately in the center of the left-right direction LR of the front case 250 and the lower case 220, is a round hole, while the other holes 40-1, 40-2, and 40-4 are elongated holes. The engagement of holes 40-1 to 40-4 and the pins 221 restricts the movement of the first reinforcing member 310 in the front-rear direction FB, while allowing movement in the left-right direction LR.

[0024] The upper horizontal plate 313b of the fixing part 313 is provided with three screw holes 33-1 to 33-3 arranged in the front-to-back direction FB. The front and rear screw holes 33-1 and 33-3 are elongated holes that are long in the left-to-right direction LR. The screw hole 33-2 between the front and rear screw holes 33-1 and 33-3 is a round hole. The lower horizontal plate 313c of the fixing part 313 is provided with a round screw hole 33-4.

[0025] As shown in Figure 5, the second reinforcing member 320 is provided in a substantially L-shape that is long in the left-right direction LR. The length of the second reinforcing member 320 in the left-right direction LR is sufficiently shorter than that of the first reinforcing member 310. The second reinforcing member 320 has a front plate 321 that is provided with a width approximately equal to the vertical direction UL (width direction) of the front case 250, and a lower plate 322 that is bent from the lower end edge of the front plate 321 toward the rear B and is sufficiently narrower in width than the front plate 321. An engaging piece 321a (first projection) is provided at the left end of the front plate 311, which is bent toward the front F in a tongue shape with the plate surface oriented in the left-right direction LR.

[0026] A tongue-shaped engaging piece 321b is provided on the left side L of the center of the front plate 321, and a tongue-shaped engaging piece 321c is provided on the right side R of the center of the front plate 321. The engaging piece 321b (second projection) is provided by bending the plate surface in the vertical direction UL towards the front F. As shown in the enclosed diagram of P3, the engaging piece 321b has a roughly rectangular shape with an inclined portion 321b1 that is inclined outward (right side case 240 side of the right side R) so that the tip side is narrower, with the plate surface in the vertical direction UL. The engaging piece 321c (first projection) is provided by bending the plate surface in the horizontal direction LR towards the front F. The engaging piece 321c has a roughly rectangular shape.

[0027] The right end portion of the front plate 321 is provided with two vertically aligned protrusions 321d (contact protrusions) (see also Figure 11). Between the two protrusions 321d, a concave groove 321e is provided, extending in the left-right direction LR, for reinforcement. The front side F of the concave groove 321e is concave. In addition, a protruding piece 321f is provided above the right end R of the front plate 321 (upper side of the protrusions 321d), projecting the plate surface in the front-rear direction FB.

[0028] A fixing portion 323 is provided at the right R end of the front plate 321, which is bent to the rear B. The fixing portion 323 includes a vertical plate 323a with its surface facing left to right, an upper horizontal plate 323b bent to the left L from the upper end of the vertical plate 323a with its surface facing up to down UL, and a lower horizontal plate 323c bent to the right R from the lower end of the vertical plate 313a with its surface facing up to down UL. The vertical plate 323a is provided with a concave groove portion 323e that is connected to the concave groove portion 321e of the front plate 321 and is provided in the front-to-back direction FB. Furthermore, a bent portion 323f is provided at the rear B of the vertical plate 323a, which is bent to the left L. The lower horizontal plate 323c is provided with a projection piece 323d bent upward Up with its surface facing left to right LR. The projection pieces 321f and 323d have their tips bent.

[0029] The front plate 321 is provided with a plurality of (four in this embodiment) screw holes 34-1 to 34-4 through which screw members 81 for fixing to the front case 250 are inserted. The bottom plate 322 is provided with a plurality of (two in this embodiment) screw holes 35-1 to 35-2 through which screw members 82 for fixing to the lower case 220 are inserted. The rear edge B of the bottom plate 322, corresponding to the screw holes 35-1, 35-2 and the hole portion 41-1 described later, protrudes slightly from the rear B.

[0030] At the right R end of the front plate 321, two screw holes 34-1 and 34-2 are provided, one above the other, flanking a concave groove 321e. On the other hand, at the left L end of the front plate 321, two screw holes 34-3 and 34-4 are provided, one above the other, flanking. Of the multiple screw holes 34-1 to 34-4 provided in the front plate 321, the screw holes 34-1 and 34-2 on the right R are round holes, while the screw holes 34-3 and 34-4 on the left L are elongated holes that are long in the left-right direction (LR).

[0031] The screw holes 35-1 and 35-2 provided in the lower plate 322 are elongated holes that are long in the left-right direction (LR). A pin 221, which is erected from the lower case 220, is inserted through a hole 41-1, which is an elongated hole that is long in the left-right direction (LR) and is provided between the screw holes 35-1 and 35-2 in the left-right direction (LR). The engagement between the hole 41-1 and the pin 221 restricts the movement of the second reinforcing member 320 in the front-rear direction (FB) to position it, while allowing it to move in the left-right direction (LR).

[0032] The upper horizontal plate 323b of the fixing part 323 is provided with three screw holes 36-1 to 36-3 arranged in the front-to-back direction FB. The front and rear screw holes 36-1 and 36-3 are elongated holes that are long in the left-to-right direction LR. The screw hole 36-2 between the front and rear screw holes 36-1 and 36-3 is a round hole. The lower horizontal plate 323c of the fixing part 323 is provided with a round screw hole 36-4.

[0033] The mounting relationship between the reinforcing members 300 (first reinforcing member 310, second reinforcing member 320) and the front case 250 and lower case 220 will be explained. As shown in Figures 6 and 7, the upper end of the front case 250 protrudes to the rear side B in a cross-sectional view, and the front plates 311 and 321 of the reinforcing members 300 (first reinforcing member 310, second reinforcing member 320) are attached below it in a surface-jointed manner. In addition, the lower end of the front case 250 is provided in a stepped shape.

[0034] As shown in Figure 2 (especially enclosed diagrams Q1, Q3, and Q4), screw members 81, which are wood screws, are inserted through the screw holes 31-1 to 31-12 in the front plate 311 of the first reinforcing member 310 and the screw holes 34-1 to 34-4 in the front plate 321 of the second reinforcing member 320 and fastened to the front case 250. In addition, screw members 82, which are screws, are screwed into the female threads provided on the lower case 220, which correspond to the screw holes 32-1 to 32-10 in the lower plate 312 of the first reinforcing member 310 and the screw holes 35-1 and 35-2 in the lower plate 322 of the second reinforcing member 320.

[0035] As shown in the enclosed diagram of section Q1 in Figure 2, the front case 250 is provided with a long, concave engaging recess 251 (first recess) in the left-right direction LR, corresponding to the engaging piece 311c of the first reinforcing member 310. The engaging recess 251 is made slightly larger in the width direction (up-down direction UL) than the width of the engaging piece 311c. Therefore, the engagement between the engaging piece 311c and the engaging recess 251 allows movement of the engaging piece 311c in the left-right direction LR, but restricts movement of the engaging piece 311c in the up-down direction UL. Thus, the front case 250 is positioned in the up-down direction UL relative to the first reinforcing member 310, and movement of the engaging piece 311c in the left-right direction LR is permitted.

[0036] As shown in the enclosed diagram of section Q2 in Figure 2, the front case 250 is provided with a substantially rectangular concave recessed portion 252 (second recess) corresponding to the engaging piece 311b of the first reinforcing member 310. Also, as shown in Figure 10, the flat surface at the left end of the front case 250 abuts against the projection 311d and projection piece 311f of the front plate 311. The front case 250 is positioned in the left-right direction LR relative to the first reinforcing member 310 by the projection 311d. When attaching the front case 250 to the first reinforcing member 310, the left end of the front case 250 abuts against the projection 311d and the recessed portion 252 is pushed into the engaging piece 311b, causing the inclined portion 311b1 of the engaging piece 311b to bite into the wall surface of the recessed portion 252 opposite to the inclined portion 311b1. In this way, the front case 250 is positioned relative to the first reinforcing member 310 and is restricted from easily moving relative to the first reinforcing member 310.

[0037] As shown in the enclosed diagram of section Q4 in Figure 2, the front case 250 is provided with a long, concave recessed area 253 (first recess) in the left-right direction LR, corresponding to the engaging piece 321c of the second reinforcing member 320. The width of the recessed area 253 (up-down direction UL) is slightly larger than the width of the engaging piece 321c. The engagement between the engaging piece 321c and the recessed area 253 allows movement of the engaging piece 321c in the left-right direction LR, while restricting movement in the up-down direction UL. Therefore, the front case 250 is positioned in the up-down direction UL relative to the second reinforcing member 320.

[0038] As shown in the enclosed diagram of section Q3 in Figure 2, the front case 250 is provided with a substantially rectangular concave recessed portion 254 (second recess) corresponding to the engaging piece 321b of the second reinforcing member 320. Also, as shown in Figure 11, the flat surface at the right end of the front case 250 abuts against the projection 321d and projection piece 321f of the front plate 321. The front case 250 is positioned in the left-right direction LR relative to the second reinforcing member 320 by the projection 321d. When attaching the front case 250 to the first reinforcing member 310, the right end of the front case 250 abuts against the projection 321d and the recessed portion 254 is pushed into the engaging piece 321b, causing the inclined portion 321b1 of the engaging piece 321b to bite into the wall surface of the recessed portion 254 opposite to the inclined portion 321b1. In this way, the front case 250 is positioned relative to the second reinforcing member 320 and is restricted from easily moving relative to the second reinforcing member 320.

[0039] Furthermore, as shown in the enclosed diagram of section Q3 in Figure 2, the engaging pieces 311a and 321a of the first reinforcing member 310 and the second reinforcing member 320, respectively, engage with a long, concave recessed recess 255 (first recess) in the left-right direction (LR) that is provided in the front case 250 corresponding to the engaging pieces 311a and 321a. The vertical UL of the recessed recess 255 is slightly larger than the vertical UL (width) of the engaging pieces 311a and 321a. As a result, the front case 250 is positioned vertically relative to the first reinforcing member 310 and the second reinforcing member 320.

[0040] The right end of the first reinforcing member 310 and the left end of the second reinforcing member 320 are designated as division points for the reinforcing member 300, and there is a predetermined gap between the right end of the first reinforcing member 310 and the left end of the second reinforcing member 320. The gap S1 between the front plates 311 and 321 and the gap S2 between the lower plates 312 and 322 are offset in the left-right direction.

[0041] As shown in Figure 6, the upper horizontal plate 313b of the fixing portion 313 of the first reinforcing member 310 is fixed by inserting a screw member 83 through the front and rear screw holes 33-1 and 33-3 (see Figure 4) and screwing it into the female screw portion provided on the boss 222 that rises from the lower case 220. On the other hand, as shown in Figure 8, a screw member 84 is inserted from the lower Lo into the screw hole 33-2 of the upper horizontal plate 313b, which is sandwiched between the front and rear screw holes 33-1 and 33-3, and screwing it into the member constituting the left side case 230 to fix it. In addition, a screw member 85 is inserted from the lower Lo through the lower case 220 into the screw hole 33-4 of the lower horizontal plate 313c and screwing it into the member constituting the left side case 230 to fix it. In this way, the left side case 230 is fixed to one end of the first reinforcing member 310. Furthermore, the hole 224 in the lower case 220 through which the screw member 85 is inserted is an elongated hole that is long in the left-right direction (LR). In addition, the inner surface (right side R) of the projection piece 313d of the lower horizontal plate 313c is close to or in contact with the projection 231 that protrudes downward (Lo) on the left side case 230, thereby positioning the first reinforcing member 310 in the left-right direction (LR) relative to the left side case 230.

[0042] As shown in Figure 7, the upper horizontal plate 323b of the fixing portion 323 of the second reinforcing member 320 is fixed by inserting a screw member 83 through the front and rear screw holes 36-1 and 36-3 (see Figure 4) and screwing it into the female screw portion provided on the boss 223 that rises from the lower case 220. On the other hand, as shown in Figure 9, a screw member 84 is inserted from the lower Lo into screw hole 36-2, which is sandwiched between the front and rear screw holes 36-1 and 36-3 of the upper horizontal plate 323b, and screwing it into the member constituting the right side case 240 to fix it. Also, a screw member 85 is inserted from the lower Lo into screw hole 36-4 of the lower horizontal plate 323c and screwing it into the member constituting the right side case 240 to fix it. In this way, the right side case 240 is fixed to one end of the second reinforcing member 320. Furthermore, the hole 224 in the lower case 220 through which the screw member 85 is inserted is an elongated hole that is long in the left-right direction LR. In addition, the inner surface (left side L) of the projection piece 323d of the lower horizontal plate 323c is close to or in contact with the projection 241 that protrudes downward Lo on the right side case 240, thereby positioning the second reinforcing member 320 in the left-right direction LR relative to the right side case 240.

[0043] This section explains the relationship between the reinforcing members 300, which correspond to the expansion and contraction of the front case 250 and lower case 220 when the outside temperature changes, and the front case 250, lower case 220, and side cases. For example, when the outside temperature rises, the lower case 220, which is made of resin material, expands, and the front case 250, which is made of wood material, contracts. When the outside temperature falls, the lower case 220 contracts, and the front case 250 expands. On the other hand, since the reinforcing members 300 (first reinforcing member 310, second reinforcing member 320) are sheet metal members, their expansion and contraction due to normal changes in outside temperature are sufficiently smaller than that of the lower case 220 and front case 250.

[0044] The fixing portions 313 and 323 of the reinforcing members 300 (first reinforcing member 310, second reinforcing member 320) are fixed to the side cases (left side case 230, right side case 240) via round screw holes 33-2, 33-4, 36-2, and 36-4. Therefore, the first reinforcing member 310 and the second reinforcing member 320 are fixed to the side cases (left side case 230, right side case 240) in such a way that their relative movement is restricted.

[0045] Furthermore, in the first reinforcing member 310, the engaging piece 311b having an inclined portion 311b1 is positioned on the left side case 230 side of the elongated screw hole 31-3 closest to the left side case 230. Moreover, on the left side case 230 side of the engaging piece 311b, the first reinforcing member 310 and the front case 250 are fixed via the round screw holes 331-1 and 31-2. Therefore, the first reinforcing member 310 and the front case 250 are fixed in such a way that relative movement is restricted near the left end of the front case 250. In other words, the gap between the front case 250 and the left side case 230 does not change even when the front case 250 expands or contracts. On the other hand, in the portion inside (right side R) of the engaging piece 311b, the first reinforcing member 310 and the front case 250 are fixed via elongated screw holes 31-3 to 31-12, so that, as will be described later, the first reinforcing member 310 and the front case 250 are fixed in a way that allows for relative movement.

[0046] Similarly, in the second reinforcing member 320, the engaging piece 321b having the inclined portion 321b1 is positioned on the right side case 240 side of the elongated screw holes 34-3 and 34-4 closest to the right side case 240. Therefore, the gap between the right side case 240 and the front case 250 does not change. That is, the second reinforcing member 320 and the front case 250 are fixed in such a way that relative movement is restricted near the right end of the front case 250, while the second reinforcing member 320 and the front case 250 are fixed so as to be able to move relative to each other in the portion inside (left side L) of the engaging piece 321b.

[0047] On the other hand, the reinforcing members 300 (first reinforcing member 310, second reinforcing member 320) are fixed to the lower case 220 via elongated screw holes 32-1 to 32-10, 35-1, and 35-2. The fixing parts 313 and 323 are also fixed to the lower case 220 via elongated screw holes 33-1, 33-3, 36-1, and 36-3. Therefore, the reinforcing members 300 (first reinforcing member 310, second reinforcing member 320) are relatively movable with respect to the lower case 220. In other words, when the lower case 220 expands or contracts due to changes in ambient temperature, the lower surface of the head of the screw member 82, which is attached to the elongated screw holes 32-1 to 32-10, 35-1, 35-2, 33-1, 33-3, 36-1, 36-3, slides against the surfaces of the lower plates 312, 322, the upper horizontal plates 313b, 323b, and the lower horizontal plates 313c, 323c, allowing the reinforcing members 300 (first reinforcing member 310, second reinforcing member 320) to move relative to the lower case 220.

[0048] Similarly, at the locations where the reinforcing members 300 (first reinforcing member 310, second reinforcing member 320) are fixed to the front case 250 via the elongated screw holes 31-3 to 31-12, 34-3, and 34-4 in the front plates 311 and 321, slippage occurs between the jaw portion of the head of the screw member 81 and the front plates 311 and 321.

[0049] Therefore, for example, when the outside temperature rises, the left side case 230 and the first reinforcing member 310 move to the right R in accordance with the contraction of the front case 250, and the right side case 240 and the second reinforcing member 320 move to the left L. As a result, the predetermined gaps S1 and S2 at the portion where the first reinforcing member 310 and the second reinforcing member 320 are separated shrink. At this time, the lower case 220 expands in the left-right direction L, but since the first reinforcing member 310, the second reinforcing member 320 and the lower case 220 are relatively movable, no undue strain occurs in the lower case 220. When the outside temperature drops, each member expands and contracts and moves in the opposite direction.

[0050] Therefore, the gap between the left and right ends of the front case 250 and the side cases (left side case 230, right side case 240) remains constant even when the outside temperature changes. Thus, the gap between the front case 250 and the side cases, which are visible to the performer, does not change, ensuring a high level of aesthetic appeal.

[0051] Furthermore, as shown in Figures 8 and 9, the lower case 220 and the side cases (left side case 230, right side case 240) have elongated screw holes (e.g., holes 224) that connect them, and predetermined gaps S3 and S4 are provided on the lower surface of the case 200 between the lower case 220 and the side cases (left side case 230, right side case 240). As a result, the movement of the side cases (left side case 230, right side case 240) is not restricted by the lower case 220, and since the gaps S3 and S4 are located on the lower surface, they are not visible to the performer.

[0052] Furthermore, since the approximate central portion of the case 200 in the left-right direction (LR) is less affected by expansion and contraction, the length of the screw holes 32-6 (located in the lower plate 312 of the first reinforcing member 310) in this portion is shorter in the left-right direction (LR) than in other parts. Similarly, the holes 40-3 are round holes.

[0053] Furthermore, by positioning the division of the reinforcing member 300 (part Q3 in Figure 2) to the right, avoiding the approximate center of the left-right direction (LR) of the case 200, the rigidity of the approximate center of the left-right direction (LR) of the case 200 is increased. In addition, since the left side case 230, where the operating section 14 is located, is heavier than the right side case 240, where the operating section is not located, positioning the division of the reinforcing member 300 to the right increases the rigidity of the heavier left side case 230 in the case 200.

[0054] Although not shown in the diagram, the lower case 220 and the rear panel are not affected by the behavior of the front case 250, the side cases (left side case 230, right side case 240), and the lower case 220, as the rear panel is appropriately divided into left and right (L and R) sections.

[0055] In the embodiments of the present invention described above, the case 200 comprises a lower case 220 made of a resin material as the first material, which is long in one direction, the left-right direction LR; a plurality of reinforcing members 300 (first reinforcing member 310, second reinforcing member 320) fixed to the lower case 220 and made of a steel plate (sheet metal material) as the second material, which is a material with a coefficient of thermal expansion smaller than that of the first material (resin material), which are divided and arranged in the left-right direction LR; a front case 250 formed to be long in one direction and fixed across the plurality of reinforcing members 300; and side cases (left side case 230, right side case 240) arranged adjacent to the front case 250 and fixed to one end of the reinforcing member 300.

[0056] As a result, even if the amount of expansion and contraction due to changes in ambient temperature differs between the front case 250 and the lower case 220, the divided reinforcing member 300 moves in sync with the side case and the front case 250, and the gap between the side case and the front case 250 remains constant. Therefore, even when combining parts made of different materials, such as the front case 250 and the lower case 220, the appearance is not compromised and no damage to the components occurs.

[0057] Furthermore, the multiple reinforcing members 300 are divided asymmetrically. This allows the division positions to be set according to the area to be reinforced.

[0058] Furthermore, the reinforcing members 300 positioned at one end of the multiple reinforcing members 300, i.e., the first reinforcing member 310 and the second reinforcing member 320 in this two-part embodiment, are fixed to the front case 250 and the side case in such a way that their relative movement is restricted, while they are fixed to the lower case 220 in such a way that they can move relative to each other. Specifically, round screw holes are provided where relative movement is restricted, and elongated holes are provided where they are fixed in such a way that they can move relative to each other. This allows the reinforcing members 300 positioned at the side case and end to move in sync with the expansion and contraction of the front case 250.

[0059] Furthermore, the reinforcing member 300 positioned at one end includes round screw holes 31-1, 31-2, 34-1, 34-2, 33-2, 33-4, 36-2, 36-4 through which screw members are inserted to fix it to the front case 250 and the side case, elongated screw holes 31-3 to 31-12, 34-3, 34-4 through which screw members are inserted to fix it to the front case 250, and elongated screw holes 32-1 to 32-10, 35-1, 35-2 through which screw members are inserted to fix it to the lower case 220. This allows for restricting or enabling relative movement with a simple configuration.

[0060] Furthermore, the reinforcing member 300 has tongue-shaped first projections (engaging pieces 311a, 311c, 321a, 321c), and the front case 250 has first recesses (engaged recesses 251, 255, 253) that engage with the first projections. The engagement of the first projections and the first recesses restricts the movement of the first projections in a direction perpendicular to one direction (left-right direction LR) (up-down direction UL), while allowing movement of the first projections in the other direction (left-right direction LR). This allows for vertical positioning of the reinforcing member 300 and the front case 250 while accommodating expansion and contraction in the left-right direction LR due to changes in ambient temperature.

[0061] Furthermore, the reinforcing member 300 has tongue-shaped second projections (engaging pieces 311b, 321b) with inclined portions 311b1, 321b1 on the side case side to which the reinforcing member 300 is fixed, and the front case 250 has second recesses (engaged recesses 252, 254) that engage with the second projections. This, along with the round screw holes 31-1, 31-2, 34-1, 34-2, allows for the left-right LR positioning of the reinforcing member 300 near both ends of the front case 250.

[0062] Furthermore, the reinforcing member 300 is provided with contact protrusions (protrusions 311d, 321d) that abut against the end face of the front case 250 in one direction. This makes it easier to position the front case 250 relative to the reinforcing member 300.

[0063] Furthermore, the keyboard instrument 10 is equipped with a case 200. This makes it possible to provide a keyboard instrument 10 that reduces the likelihood of its appearance being damaged or the components being damaged due to changes in external temperature, even when different materials are combined.

[0064] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents.

[0065] The invention described in the first claim of this application is listed below. [1] The first material is used as the material, and the lower case is longer in one direction, A plurality of reinforcing members are fixed to the lower case, made of a second material having a coefficient of thermal expansion smaller than that of the first material, and arranged in a divided manner in one direction, A front case formed to be elongated in one of the aforementioned directions and fixed across the plurality of reinforcing members, A side case is positioned adjacent to the front case and fixed to one end of the reinforcing member, A case equipped with this feature. [2] The case according to [1], wherein the plurality of reinforcing members are divided asymmetrically. [3] The case according to [1] or [2], wherein the reinforcing member, which is positioned at one end of the plurality of reinforcing members, includes a portion fixed to the front case so as to be movable relative to it and a portion fixed so as to restrict its relative movement, is fixed to the side case so as to restrict its relative movement and is fixed to the lower case so as to be movable relative to it. [4] The case according to any one of [1] to [3], wherein the reinforcing member positioned at the end in one direction includes a round screw hole through which a screw member is inserted to fix it to the front case and the side case, an elongated screw hole through which a screw member is inserted to fix it to the front case, and an elongated screw hole through which a screw member is inserted to fix it to the lower case. [5] The reinforcing member has a tongue-shaped first projection, The front case has a first recess that engages with the first projection, The engagement of the first projection and the first recess restricts the movement of the first projection in a direction perpendicular to the one direction, and allows the movement of the first projection in the one direction, as in any of the cases described in [1] to [4] above. [6] The reinforcing member has a tongue-shaped second projection which has an inclined portion on the side case side to which the reinforcing member is fixed, The front case is the case according to any one of [1] to [5], having a second recess that engages with the second projection. [7] The case according to any one of [1] to [6], wherein the reinforcing member has a contact projection that abuts against the end face in one direction of the front case. [8] A keyboard instrument comprising the case described in any of [1] to [7] above. [Explanation of Symbols]

[0066] 3 White keys 4 Black keys 5 Keyboard 6 Keyboard layout area 10-key keyboard instrument, 12 knobs 14 Control panel 18 Earphone jack 31-1~31-12, 32-1~32-10, 33-1~33-4 threaded holes 34-1~34-4, 35-1~35-2, 36-1~36-4 threaded holes 40-1~40-4,41-1 Hole 81-85 Screw components 200 Case 210 Upper Case 211 Top panel 220 Bottom case 221 Pin 222 Boss 223 Boss 224 Hole 230 Left side case 231 Protrusion 240 Right side case 241 Protrusion 250 Front case 251-255 Engaged recess 300 Reinforcement member 310 First reinforcement member 311 Front plate 311a Engaging piece 311b Engagement piece 311b1 Inclined part 311c Engagement piece 311d Projection 311e Concave groove 311f Projection piece 312 Lower plate 313 Fixed part 313a Vertical board 313b Upper horizontal board 313c Lower horizontal plate 313d Projection piece 313e Concave groove section 313f Bent section 320 Second reinforcing member 321 Front plate 321a Engagement piece 321b Engagement piece 321b1 Inclined part 321c Engagement piece 321d Protrusion 321e Concave groove 321f Projection piece 322 Lower plate 323 Fixed part 323a Vertical plate 323b Upper horizontal plate 323c Lower horizontal plate 323d Projection piece 323e Concave groove 323f Bending section S1~S4 Gap

Claims

1. The first material is used as the base material, and the lower member extends in the direction of the key arrangement, A plurality of reinforcing members are fixed to the lower member, made of a second material with a coefficient of thermal expansion smaller than that of the first material, and arranged in a divided manner in the direction of the key arrangement, A front member made of a third material having a different coefficient of thermal expansion from the first material and a larger coefficient of thermal expansion than the second material, extending in the direction of the arrangement of the keys and fixed across the plurality of reinforcing members, A case for keyboard instruments equipped with the following features.

2. The keyboard instrument case according to claim 1, wherein the first material is a resin material, the second material is a metal material, and the third material is a wood material.

3. The keyboard instrument case according to claim 1 or claim 2, further comprising a side member positioned adjacent to the front member and fixed to one end of the reinforcing member.

4. The keyboard instrument case according to any one of claims 1 to 3, wherein the reinforcing member includes a portion fixed so as to be movable relative to the front member and a portion fixed so as to restrict relative movement.

5. The case for a keyboard instrument according to claim 3, wherein the reinforcing member is fixed such that its relative movement with respect to the side member is restricted.

6. The case for a keyboard instrument according to any one of claims 1 to 5, wherein the reinforcing member is fixed so as to be movable relative to the lower member.

7. The keyboard instrument case according to any one of claims 1 to 6, wherein the reinforcing member is provided with a contact projection that abuts against the end face of the front member in the direction of the arrangement of the keys.

8. A keyboard instrument comprising a case for a keyboard instrument as described in any one of claims 1 to 7.

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