JPH0128956B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention prevents the keys from tilting or wobbling during key press operations, and also involves deburring the insertion holes punched into the keyboard frame or applying tape to hide the burrs. The present invention relates to a keyboard device for an electronic musical instrument that eliminates the need for.

Traditionally, keyboard devices in electronic musical instruments such as electronic organs have been manufactured by press working and a plurality of keys integrally formed of synthetic resin, with the plurality of keys on the top surface rotating in the vertical direction. The keyboard frame includes a freely disposed keyboard frame, and a return spring that is interposed between each key and the keyboard frame to give the keys a constant return habit. In this case, each key has an engagement recess provided at its rear end that engages with one side edge of an insertion hole punched in the keyboard frame or with a fulcrum plate, and the key is rotated using this engagement recess as a rotation fulcrum. It is configured as follows. That is, FIG. 1 shows a conventional example in which a key 3 is supported by a fulcrum plate 2 fixed to the rear end surface of a keyboard frame 1. A substantially trapezoidal engagement recess 4 into which the upper end of the key 3 engages is provided, and a return spring 5 made of a tension coil spring constantly biases the key 3 so that the front end of the key 3 rises. On the other hand, in FIG. 2, a fulcrum plate 2 is integrally provided at the rear end of the keyboard frame 1 by bending.
A protrusion 7 integrally protruding from the rear end surface of the key 3 is inserted into an insertion hole 6 punched and formed in the key 3, and a return spring made of a compression coil spring is inserted into the engagement recess 4 provided on the upper surface of the protrusion 7. The upper edge 6a of the insertion hole 6 is engaged with the upper end edge 6a of the insertion hole 6 with a force of 5.

However, in such conventional keyboard devices,
In both cases, the recess 4 of the key 3 is supported by the upper end of the fulcrum plate 2 or the upper edge 6a of the insertion hole 6 only by the force of the return spring 5, so that the force when pressing the key is shifted from the center of the key 3. When this happens, in addition to the force that rotates the key 3 downward, there is also a force that tends to tilt the key 3 in the left-right direction, and if this force is stronger than the spring force, the key 3 will be tilted easily and the touch feeling will deteriorate. At the same time, it had the disadvantage of generating noise.

Therefore, as a method to prevent such drawbacks, the third method is
A keyboard device as shown in the figure is known. In this keyboard device, an insertion hole 6 is provided on the surface of a keyboard frame 1, and a mounting foot 8 integrally provided on the lower surface of the rear end of the key 3 is inserted into the insertion hole 6, and the engaging recess 4 is inserted into the insertion hole 6. It is engaged with the rear end edge 6b by the force of the return spring 5. According to such a keyboard device, the key 3 is given a clockwise rotational habit by the return spring 5 and is also urged backward, so that the inclination of the key 3 forms the recess 4. It is almost completely regulated by the upper and lower side walls 4a, 4b and the rear end edge 6b of the insertion hole 6. Therefore, it can be said that this is superior to the conventional examples shown in FIGS. 1 and 2 in that the key 3 has less rattling and noise and can perform good key operations, but on the other hand, Another problem is that the rotation fulcrum has poor durability.

That is, since the keyboard frame 1 is usually formed of a metal plate and the insertion hole 6 is punched out using a press machine, there is no sagging around the entire edge of the insertion hole 6 as shown in FIGS. 4a and 4b. 9 and burr 10 inevitably occur. Note that Figure A shows the case where the insertion hole 6 is punched out from the front side of the keyboard frame 1, and Figure B shows the case where it is punched out from the back side. This kind of sauce 9 and bari 10
Among them, the burr 10 in particular protrudes toward the front or back side of the keyboard frame 1, so when the engagement recess 4 comes into contact with the rear end edge 6b of the insertion hole 6, the burr 10 is caused to protrude toward the side wall 4a or 4b. Root part 11 of
a or 11b. Therefore, when the key 3 rotates during a key press operation, the burr 10 bites into the base portion 11a or 11b, and is gradually scraped off during long-term use. This scraping phenomenon becomes more severe as the key is pressed more strongly, because the fulcrum portion, that is, the engagement recess 4 is more likely to swing, thereby increasing the width W of the recess 4. This increase in width W causes the key 3 to rattle in the vertical direction, and this rattle further promotes scraping by the burr 10. Therefore, good key operation cannot be obtained, noise is generated, and if the scraped debris adheres to the keyswitch etc. located below the keyboard frame 1, it may cause contact failure and cause the instrument to not produce sound. This will have a negative impact on its own performance, reliability, etc.

Therefore, it is possible to remove the burr 10 through post-processing or cover the burr 10 with adhesive tape, but in that case, extra processing and tape attachment work are required. This results in the inconvenience of high manufacturing costs. Also, the third
In the fulcrum structure shown in the figure, since the engagement recess 4 constitutes an undercut, a slide core is required, which makes the mold complicated and expensive, and its maintenance is also very troublesome. There were flaws.

This invention was made in view of the above-mentioned points, and prevents the inclination of keys, scraping due to burrs, and noise generation, provides stable and good key pressing operation, and eliminates the need for slide cores, deburring work, etc. This provides a keyboard device for an electronic musical instrument that can be manufactured at low cost without having to use the keyboard frame. a return spring that imparts a return habit, and an engagement recess and a chevron-shaped receiving part that cooperate with each other to constitute a rotational fulcrum of the key are provided at the rear end of the key, the engagement recess consists of a bottom portion that comes into contact with one end edge of the insertion hole punched in the keyboard frame, and an inclined side wall portion that faces the peripheral edge of the insertion hole on the sagging side surface of the keyboard frame; The portion is provided to be offset in the width direction of the key with respect to the engagement recess, and of the two slopes, the slope located on the side wall portion side is on the burr generation side surface of the keyboard frame and is located at the peripheral edge of the insertion hole. opposing sides substantially forming the other side wall of the engagement recess, and causing the ridgeline part of the chevron-shaped receiving part to abut against the peripheral edge of the insertion hole on the burr-generating side surface of the keyboard frame. It is.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 5 is a sectional view showing a first embodiment of the keyboard device according to the present invention, and FIG. 6 is a bottom view of the key. In these figures, reference numeral 21 denotes a key integrally formed of synthetic resin, and the key 21 is formed by hollowing out the back surface, so that the cross-sectional shape is approximately U-shaped, and there is a key on the bottom surface of the rear end. are both side plates 21 of the key 21
A protrusion 22 is provided that extends downward from a and 21b, and an engagement recess 23 that constitutes a rotation fulcrum is provided on the front surface of this protrusion 22. Further, the detailed structure of the projection 22 and the engagement recess 23 will be explained based on FIGS. 7 and 8. The projection 22 is provided in a substantially rectangular cylindrical shape to protrude along the inner surfaces of the side plates 21a and 21b. By this, the width is the same as the distance between the inner surfaces. The engagement recess 23 is formed over the entire length of the protrusion 22 in the width direction,
It has one side wall portion 25 and a vertical bottom surface 27 that is flush with the front surface 22a of the protrusion 22. The side wall portion 25 is constituted by the upper surface of a protrusion portion 26 that protrudes forward from the lower end of the front surface of the protrusion 22, and is inclined downwardly to the left as shown in FIG. The surface of the insertion hole 31 on the opposite side to the burr generation side surface, which will be described later, is opposite to the peripheral edge of the insertion hole 31 on the sag generation side surface. The height h of the bottom surface 27 is set to be approximately equal to the thickness t of the keyboard frame 1 (h=t). In this case, the height h is set by the substantially ∨-shaped chevron-shaped receiving portions 28 provided at the lower end sides of the rear ends of both side plates 21a and 21b of the key 21, and the side wall portions 25. The chevron-shaped receiving portion 28 is formed such that its ridgeline portion 28A coincides with the bottom surface 27 of the engagement recess 23, and the slope 29 on the front side of the ridgeline portion 28A substantially covers the upper side wall portion of the engagement recess 23. It consists of Furthermore, as shown in FIG. 5, the rear end of the key 21 is formed with a mold extraction hole 30 that opens on the upper and lower surfaces of the key 2, and this extraction hole 30 allows the formation of the engagement recess 23 to be made. It makes it possible. Therefore, the engagement recess 23 is easily formed using only a pair of upper and lower molds without using a slide core.

A rectangular insertion hole 31 is punched out on the rear end surface of the keyboard frame 1 in correspondence with the projection 22, and the key 21 is supported by the insertion hole 31 so as to be rotatable in the vertical direction. There is. That is, key 2
1 inserts the protrusion 22 into the insertion hole 31 from above and moves it forward, bringing the bottom surface 27 of the engagement recess 23 into close contact with the front edge 33 of the insertion hole 31, thereby moving the engagement recess 23 to the pivot point 0. The side wall portion 25, in other words, the protrusion portion 26 is located on the back side of the peripheral edge of the insertion hole 31, thereby preventing it from coming off upward. Each ridge line portion 28A of the chevron-shaped receiving portion 28 comes into contact with the peripheral surface of the insertion hole 31, and this and the protrusion portion 26 prevent the key 21 from shaking in the vertical direction. Note that rattling of the key 21 in the left-right direction can be prevented by forming the width of the insertion hole 31 to be approximately the same as or slightly larger than the protrusion 22. Returning again to FIGS. 5 and 6, the structure of the key 21 will be explained. This key 21 further has a substantially hook-shaped stopper 35 hanging from the lower surface of the front end of the side plates 21a, 21b. The lower end of the stopper 35 is engaged in a through hole 60 formed in the front surface of the keyboard frame 1 so as to be movable up and down.
Therefore, the key 21 is allowed to rotate by a small angle in the vertical direction due to the height dimension of the through hole 60, and is always given a return habit in the clockwise direction in FIG. 5 by the force of the return spring 36, which will be described later. ing. Then, when the front end of the key 21 is pressed against the return spring 36, the key 21 rotates downward in the counterclockwise direction with the engagement recess 23 as the rotation fulcrum 0, and as a result, one side plate 21
An actuator 37 installed vertically at b operates a key switch 38 fixed to the keyboard frame 1, thereby electrically generating a musical tone corresponding to the key 21.

A pair of spring receiving walls 41 and 42 which are long in the front and back direction are vertically provided at the center of the inner bottom surface 40 of the key 21, and the lower ends thereof are curved in an arc shape as shown in the figure. Moreover, these pair of spring receiving walls 41, 42
Projections 43 and 44 are provided vertically at the lower ends of the tips of the key 21, and these pair of projections 43 and 44 and the lower ends of the tips of the spring receiving walls 41 and 42 constitute a spring locking portion 45 of the key 21. ing.

The return spring 36 is made of a flat spring having a shape as shown in FIG. 9 by punching out a metal plate of an appropriate thickness, and one end 36A of the return spring 36 is rotatable by a spring locking portion 45 of the key 21. The other end 36B is inserted into a later-described spring locking portion 46 provided on the keyboard frame 1 and is rotatably locked.
One end 36A and the other end 36 of the return spring 36
The width _W2 of B is smaller than the width of the spring body 36C,
In addition, the distance D between the pair of protrusions 43 and 44 is set to be somewhat smaller. And the return spring 36
One end 36A is inserted between the pair of protrusions 43 and 44 from behind and is rotatably locked to a spring locking portion 45. At this time, the spring body 36C and one end 3
Step portions 49 and 50 provided at the border of 6A abut against the back surfaces of the pair of projections 43 and 44.

The spring locking portion 46 of the keyboard frame 1 is connected to the key 21.
and the other end 36B of the return spring 36.
is rotatably locked as shown in FIG. That is, this spring locking part 45 is formed by bending a substantially T-shaped spring hole 51 provided in the keyboard frame 1 and a part of the narrower side edges of this spring hole 51 upward as shown in the figure. The other end 36B of the return spring 36 and the spring body 36 are configured by a pair of left and right spring receiving steps 52A, 52B.
It rotatably receives stepped portions 53 and 54 provided at the boundary with C, and prevents the spring from coming off downward.

The return spring 36 maintains a flat plate state in its natural state before being assembled, and is installed between the key 21 and the keyboard frame 1 in a buckled state. This is key 2
The distance between the spring locking part 45 of 1 and the spring locking part 46 of the keyboard frame 1 is the spring body 36 of the return spring 36.
This is because the length C is set to be somewhat shorter than the length L, and when the key 21 is attached, the return spring 36 is compressed in the longitudinal direction by the spring locking part 45.
As shown in the figure, the key 21 is buckled and deformed in an arc shape, and the reaction force P of the spring 36 generated by this deformation applies a restoring force to the key 21. In this case, the reaction force P has component forces P ₁ and P ₂ in the direction connecting the rotational fulcrum 0 of the key 21 and the spring locking part 45, and in a direction perpendicular thereto, and P ₁ causes the key 21 to be pushed upward. At this time, the rotational moment P ₁ ×L (where L is the distance from the rotational fulcrum 0 to the spring locking portion 45) becomes equal to P×l. On the other hand, P ₂ presses the engagement recess 23 of the key 21 against the front edge of the insertion hole 31. However, the vertical component of P ₂ urges the protrusion 26 provided at the lower part of the engagement recess 23 up and down, and presses it against the back side of the front edge of the insertion hole 31 .

In this case, if the return spring 36 is installed immediately after buckling, the key touch feeling will be similar to that of a conventional compression coil spring.
It is relatively lighter than when a tension coil spring or the like is used, and it is possible to obtain a touch feeling more similar to that of a general piano. In other words, when the leaf spring continues to be compressed in the longitudinal direction and reaches a certain load, the leaf spring suddenly buckles and begins to bend. After that, the bending gradually increases without increasing the load, and the reaction force of the leaf spring tends to decrease. Therefore, key 2
1, as shown in FIG. 11, even if the key 21 bends in the longitudinal direction by Δd due to the deviation between the rotational fulcrum 0 of the key 21 and the rotational fulcrum of the return spring 36 (spring locking part 46). Δd is extremely small, and unlike compression coil springs and tension coil springs, the reaction force P' does not increase significantly in proportion to the amount of displacement, and due to the lowering of the spring locking part 45, P' becomes closer to the horizontal than P. Since the moment of trying to lift the key 21 becomes smaller, as a result, as the key 21 is pushed in, the touch feeling of the key becomes lighter.

The keyboard frame 1 further includes a spring locking piece 61.
is provided. This spring locking piece 61 is attached to the key 21
This is for temporarily locking one end 36A of the return spring 36 before installing the keyboard frame 1.
A covering member 62 made of rubber, soft synthetic resin, or the like is provided integrally with the frame by cutting and bending a portion thereof and extending upwardly. Further, the spring locking piece 61 is located slightly in front of the return spring 36, so that the one end 36A of the spring 36 does not come into contact with the cover 62 when the key is pressed. and,
The spring locking piece 61 is inserted into the interior of the key 21 through the opening on the lower surface thereof, thereby functioning as a key guide and preventing the key 21 from rotating in the left-right direction. In addition, when temporarily locking one end 36A of the return spring 36 directly with the spring locking piece 61 without using the cover 62, it is preferable to provide a recess so that the spring can be locked at a certain position.

The return spring 36 is inserted into the spring hole 51 from below the keyboard frame 1 before the key 21 is installed, and its one end 36A abuts against the back surface of the cover 62 as shown by the dashed line 63 in FIG. 5, and the other end 36B is locked by the spring locking portion 46 of the keyboard frame 1, so that it is temporarily fixed on the keyboard frame 1 in a buckled and deformed state. Next, with the key 21 tilted forward and downward, the stopper 35 is inserted into the through hole 60 and the rear end of the key 21 is lowered. come down on both sides of one end 36A and press the stepped portions 49, 50 (see FIG. 9) with the back surfaces of the protrusions 43, 44.
For this reason, the return spring 36 is connected to the dashed line 63 in FIG.
36A is further compressed and deformed than the state shown in FIG.
The spring locking portion 45 locks. When the rear end of the key 21 is further lowered, the protrusion 22 is inserted into the insertion hole 31, and the key 21 moves slightly forward due to the reaction force of the return spring 36, and the engagement recess 23 is inserted into the insertion hole 31. The installation operation of the key 21 is completed by engaging the front edge of the key 21.

According to the keyboard device having such a configuration, the keys 21 can be supported stably and reliably, allowing for good key pressing operations. That is,
When the insertion hole 31 is punched out from the back side of the keyboard frame 1 and the burr 10 is made to protrude to the front side as shown in FIG. Chevron receiver 28 that restricts the downward movement of the key 21 only in part
Since the ridgeline portion 28A is located on the side of the engagement recess 23 and is in contact with the peripheral surface of the insertion hole 31, it is not scraped off by the burr 10 (actually, the opening end of the insertion hole 31 Although the inner end that contacts the edge is slightly scraped off, it can be ignored because the length is equal to the thickness of the side plates 21a and 21b), and the height h of the bottom surface 27 of the engagement recess 23 is kept constant. . This is because the presence of the burr 10 can be practically ignored as a result of the rotation fulcrum being formed by the engagement recess 23 and the chevron-shaped receivers 28 provided on both sides of the engagement recess 23. To prevent the key 21 from rattling and from generating noise. Note that a part of the bottom surface 27 and the ridgeline 28A are scraped off by the burr 10, but once a certain amount is scraped off, no more is scraped off, and the scraped part is used to prevent the rotation of the key 21. Since it does not constitute a fulcrum, there is no adverse effect on the key pressing operation of the key 21. As a result, the durability of the pivot portion of the key 21 is dramatically improved, and deburring, tape attachment, etc. are no longer necessary. Furthermore, since the engaging recess 23 can be molded without using a slide core, manufacturing and maintenance of the mold are easy and can be manufactured at low cost. In addition, the ridge portion 26 of the protrusion 22 and the chevron-shaped receiving portion 28 can prevent the key 21 from tilting in the left-right direction.

As a way to more reliably prevent the key 21 from tilting in the left and right direction, as shown in FIG.
7 height H (from the root of the slope 25 to the ridgeline 28A)
These two parts form the pivot point) are slightly smaller than the plate thickness t of the keyboard frame 1 (H<
t) At the same time as setting the ridgeline part 28A from the bottom surface 27
It is better to shift it forward by d ₁ . In this case, the engagement recess 23 will bite into the front edge 33 of the insertion hole 31, and a slight friction will occur due to the sliding effect between it and the keyboard frame 1. It is possible to completely prevent directional wobbling.

On the other hand, when the height H is set to be slightly larger than the plate thickness t (H>t), the force of the engagement recess 23 biting into the insertion hole 31 is very small, so that slippage between the engagement recess 23 and the keyboard frame 1 may occur. Friction due to the effect is less likely to occur, and it is possible to obtain a clear fulcrum structure. However, in this case, the inclination of the key 21 in the left-right direction becomes a slight sacrifice.

Note that even if the height H is changed, the portion that is shaved by the burr 10 does not pose any problem to the pivot point of the key 21, as described above, so the durability of the pivot point portion may be impaired. There isn't.

FIG. 14 is a perspective view of essential parts showing a second embodiment of the invention. As mentioned above, in this embodiment, the engagement recess 23 is provided on the lower end side of the back surface of the protrusion 22, and this engagement recess 23 is engaged with the rear end edge 70 of the insertion hole 31 by the force of a return spring (not shown). This embodiment is different from the first embodiment and has the same structure in other respects. In this case, since it is necessary for the return spring to bias the key 21 backward, a spring mounting structure as shown in FIG. 3 is adopted.

Even in such a configuration, if the burr 10 is generated on the surface side of the peripheral edge of the insertion hole 31 as shown by the thick line, the rotation fulcrum of the key 21, that is, the side wall portion 25
It is clear that the same effect as in the first embodiment can be obtained without cutting off the root portion 25a and the ridgeline portion 28A.

FIG. 15 is a perspective view of main parts showing a third embodiment of the present invention. In this embodiment, a pair of protrusions 75A, 7
5B are provided in succession on the lower surface of the rear end of each side plate 21a, 21b, and a substantially ∨-shaped chevron-shaped receiving portion 76 is provided between the pair of projections 75A, 75B. In this case, the pair of protrusions 75A, 75B are formed into a substantially L-shape and integrally have a protrusion 78,
The upper surface 78a of this protruding portion 78 and the chevron receiving portion 76
The rear side slope 76a constitutes a side wall portion of the engagement recess 80.

On the other hand, on the surface of the keyboard frame 1, a pair of left and right elongated holes 8 are formed corresponding to the pair of protrusions 75A and 75B.
1 and 82 are formed by punching, and these long holes 8
The engagement recesses 80 are respectively engaged with the rear end edges 83 of 1 and 82. As a result of this engagement, the ridgeline portion 84 of the chevron-shaped receiving portion 76 comes into contact with the surface of the keyboard frame 1 and on a straight line connecting the rear end edges 83 of the elongated holes 81 and 82. In addition, the burrs 10 of each long hole 81, 82
is provided on the front side of the keyboard frame 1.

In such a configuration, since the ridge line portion 84 is sufficiently long compared to the first and second embodiments, the influence of the burr 10 can be further reduced.
This has the advantage that the durability of the rotation fulcrum can be improved.

FIGS. 16 and 17 are a perspective view of a main part and a sectional view taken along the line A--A, showing a fourth embodiment of the present invention. This embodiment is a modification of the third embodiment shown in FIG. 15, in which the protrusions 78 of each protrusion 75A, 75B are provided to protrude forward. In this case, each side plate 21a, 21b has an engaging recess 80.
A groove 90 for forming a groove is provided in the height direction,
This prevents interference with the mold during mold release.

FIGS. 18 and 19 are a perspective view and a sectional view of essential parts showing a fifth embodiment of the present invention. In this embodiment, a protrusion 101 is integrally provided on the upper surface of a protrusion 100 protruding from the rear end surface of the key 21, and an engagement recess 1 is provided.
02 is provided. In this case, the protrusion 100
is formed by the interval between the inner surfaces of the side plates 21a and 21b, and the rear end surfaces of each side plate 21a and 21b are formed in a substantially >-shape, thereby forming the chevron-shaped receiving portion 103. The protrusion 100 is the keyboard frame 1.
The insertion hole 10 of the fulcrum plate 2 is integrally provided at the rear end of the
5, the engagement recess 102 is inserted into the upper edge 105 of the insertion hole 105 by the force of the return spring 106.
a. As a result, the side wall portion of the engagement recess 102, that is, the inclined front surface 10 of the protrusion portion 101
7 is located on the back side of the fulcrum plate 2 to prevent the key 21 from coming off, and the ridgeline part 108 of the chevron-shaped receiving part 103 comes into contact with the front side of the fulcrum plate 2.

It will be obvious that even in such a configuration, the same effects as in the first to fourth embodiments described above can be obtained simply by moving the rotational fulcrum of the key 21 to the upper surface side.

FIG. 20 is a perspective view of essential parts showing a sixth embodiment of the present invention. In this embodiment, contrary to the fifth embodiment, an engagement recess 102 is provided on the lower surface of the projection 100, and this engagement recess 102 is engaged with the lower edge 105b of the insertion hole by the force of a return spring 110. be. Note that the other configurations are designated by the same reference numerals as in FIGS. 18 and 19, and their explanation will be omitted.

In the fifth and sixth embodiments, since the engagement recesses 102 are provided on the upper and lower surfaces of the protrusion 100, there is a drawback that the key 21 is likely to tilt in the left-right direction. As in other embodiments, there is no possibility that the
The durability of the rotation fulcrum can be ensured.

As described above, the keyboard device for an electronic musical instrument according to the present invention is composed of the engagement recess and the chevron-shaped receiver, in which the rotational fulcrum of the key is shifted in the width direction of the key.
The rotational fulcrum is not scraped off by burrs generated on the periphery of the insertion hole during punching, allowing stable and reliable key pressing operation and improving the durability of the rotational fulcrum. In addition, since there is no influence from burrs, there is no need for deburring, tape pasting, etc., and manufacturing and assembly are easy. Furthermore, the engagement recess does not constitute an undercut, and therefore, it is possible to mold with a simple mold that does not use a slide core, and the manufacturing cost can be reduced, which is very effective.

[Brief explanation of drawings]

Figures 1 to 3 are side views, sectional views, and side sectional views of main parts showing the support structure of a conventional keyboard device, Figures 4a and b are diagrams for explaining the effects of burrs, and Figure 5 is a diagram showing the support structure of a conventional keyboard device. 6 is a bottom view of the key, FIGS. 7 and 8 are perspective views and rear views of the main parts of the key, and FIG. 9 is a return spring. FIG. 10 is a perspective view showing the spring locking portion of the keyboard frame, and FIG.
The figure is a diagram for explaining the action of the return spring.
Figure 2 is a diagram for explaining the effects of this invention.
Fig. 3 is a diagram showing a modification in which the bottom height of the engaging recess is changed, Fig. 14 is a perspective view of main parts showing a second embodiment of the invention, and Fig. 15 is a diagram showing a third embodiment of the invention. 16 and 17 are perspective views of essential parts and sectional views taken along the line A-A, and FIGS. 18 and 19 are perspective views of main parts showing a fourth embodiment of the present invention.
Main part perspective view and side sectional view showing the embodiment, No. 20
The figure is a perspective view of essential parts showing a sixth embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Keyboard frame, 21...Key, 22...Protrusion, 23...Engagement recess, 25...Side wall part, 26...
...Protrusion portion, 27...Bottom surface, 28...Chevron receiving portion, 2
8A...Ridge line portion, 29...Slope, 36...Returning spring, 80, 102...Engagement recess, 76, 103
...Chevron receiving part, 84,108...Ridge line part.

Claims (1)

[Claims] 1. In a keyboard device for an electronic musical instrument, which has a key arranged on a keyboard frame so as to be freely rotatable in the vertical direction, and a return spring that imparts a return habit to the key, the rear end of the key is provided with a key that cooperates with each other. and receives an engagement recess and a chevron-shaped receiving part that constitute a rotation fulcrum of the key, and the engagement recess has a bottom surface that abuts one end edge of an insertion hole punched in the keyboard frame, and It consists of an inclined side wall part facing the peripheral edge of the insertion hole on the surface of the keyboard frame on the sag generation side, and the chevron-shaped receiving part is provided offset in the width direction of the key with respect to the engaging recess, and the two Among the slopes, the slope located on the side wall side substantially constitutes the other side wall of the engagement recess on the burr generation side surface of the keyboard frame, and substantially constitutes the other side wall of the engagement recess. A keyboard device for an electronic musical instrument, wherein a ridgeline portion of the keyboard frame contacts a peripheral edge of the insertion hole on a burr-generating side surface of the keyboard frame.