JPS59133591A - Keyboard of electronic musical instrument - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a keyboard device for an electronic musical instrument that enables smooth and reliable key operations, improves touch feeling, and improves durability.

Traditionally, keyboard devices in electronic keyboard instruments such as electronic organs include a plurality of keys integrally formed from synthetic resin,
A keyboard frame manufactured by press working on which the plurality of keys are vertically swingably disposed, and a return spring, etc., which is interposed between each key and the keyboard frame and imparts a return habit to the key. It is equipped with

[Prior art]

By the way, the fulcrum structure of the key has traditionally been shown in Figures 1 to 3.
The one shown in the figure is generally adopted and implemented. That is, in FIG. 1, a key 3 is supported at the upper end of a fulcrum plate 2 fixed to the rear end surface of a frame 1 of a keyboard 7, and a key 3 is supported on the lower surface of the rear end of the key 3. A substantially trapezoidal engagement recess 4 into which the upper end engages is provided, and a return spring 5 engages the key 3.
The key 3 is given a return behavior in the direction in which the front end of the key 3 rises, that is, in the clockwise direction.

However, in the fulcrum structure of such a keyboard device, the engagement recess 4 is supported by the upper end of the fulcrum plate 2 only by the force of the return spring 5, so that the force when pressing the key is applied to the left-right center line of the key 3. If the force is applied to a position that is deviated from the spring force, a force will be generated that tilts the key 3 to the left and right in addition to a force that rotates the key 3 downward. If this force is stronger than the spring force, the key 3 will be easily tilted and the key 3 will not be touched. This has the disadvantage that it makes the user feel uncomfortable and at the same time generates noise.

FIG. 2 shows a fulcrum plate 2 integrally provided at the rear end of a keyboard frame 1 by bending and forming, and a projection integrally provided on the rear end surface of a key 3 through an insertion hole 6 punched in the fulcrum plate 2. 7 is inserted, and the retaining portion 4 provided on the upper surface of the projection γ is engaged with the upper edge 6a of the insertion hole 6 by the force of a return spring 5 made of a compression coil spring. . However, since such a fulcrum structure is basically the same as the fulcrum structure shown in FIG. 1, it has the same drawbacks.

Fig. 3 was made to solve the drawbacks caused by the fulcrum structure shown in Figs. 1 and 2. An insertion hole 6 is provided on the surface of the keyboard frame 1, and an insertion hole 6 is provided integrally on the lower surface of the rear end of the key 3. Insert the attached mounting foot 8 into the insertion hole 6 and the engagement recess 4
is pressed against the rear end edge 6b of the insertion hole 6 by the force of the return spring 5.

According to such a fulcrum structure, the key 3 is given a clockwise return habit by the return spring 5 and is also urged backward, so that the inclination of the key 3 is maintained and the vertical inclination of the four parts 4 is maintained. The lock can be almost completely controlled by the wall 4b and the rear edge 6b of the insertion hole 6, so that the key 3 can be operated with less rattling and noise. Therefore, it can be said that this fulcrum structure is superior to the fulcrum structures shown in Figures 1 and 2, but both fulcrum structures had problems with the durability of the rotating fulcrum part, as they were largely the same. .

That is, since the keyboard frame 1 is usually formed of a metal plate and the insertion hole 6 is punched out by press working, the edge of the insertion hole 6 does not sag over the entire circumference as shown in FIG. 9 and B IJ 10 will inevitably occur. Note that (a) in the same figure shows the keyboard frame 1.
0. The insertion hole 6 is punched out from the front side, and FIG. Here, among the sag 9 and the burr 10, 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 edge 6b of the insertion hole 6, the burr 10 10 abuts on the root portion 111 or 11b of the inclined wall 4 & or 4b. Therefore, when the key 3 is rotated by pressing the key,
), the burr 10 bites into the lower root portion 11b, which is the center of rotation of the key 3, and in the configuration shown in FIG. During this time, these root portions 11m and 11b are gradually scraped off. This scraping phenomenon significantly increases the bottom width W of the engagement recess 4 because the more strongly the key is pressed, the more likely the key 3 is to be tampered with. This increase in the bottom width W causes the key 3 to rattle in the vertical direction, and furthermore, this rattling promotes the removal of the burrs by the burr 10. As a result, it becomes impossible to obtain good key operation, and noise is generated. In addition, if scraped debris falls and adheres to the key switch, it may cause contact failure, resulting in no sound, which may affect the performance and reliability of the musical instrument itself. etc. have a negative impact.

In addition, support structures shown in FIGS. 5 and 6 have also been adopted. In other words, FIG. 5 can be said to be an improved version of the fulcrum structure shown in FIG. The body 15 is fitted and fixed. In such a fulcrum structure, there is no direct friction between the fulcrum plate 2 and the key 3, and there is no dimensional clearance due to the deformation of the elastic body 15, so rattling and noise can be prevented. It has advantages. However, there is friction between the fulcrum plate 2 and the elastic body 15 and between the key 3 and the elastic body 15. Of course, if the elastic body 15 is completely elastically deformed in response to the rotation of the key 3, it seems that there will be no friction, but in reality, there will always be slight friction. Since the elastic body 15 is intended to actively cause elastic deformation, a flexible material is used; however, such a material generally has low abrasion resistance due to rubbing, and therefore the above-mentioned minute It is also prone to wear due to heavy friction.

Furthermore, in the areas where the keyboard frame 1 and the elastic body 15 rub against each other, cracks are likely to occur due to burrs or the like on the keyboard frame 1, resulting in poor durability.

On the other hand, regarding the touch feeling, since only slight rubbing occurs, it can be said that there are relatively few variations in touch, stick-slip, etc. due to non-uniform rubbing as in the fulcrum structure shown in FIG. However, on the other hand, since the elastic body 15 is intended to be elastically deformed in response to the rotation of the key 3, the elastic pressure acts on the touch pressure. It exhibits properties similar to the sudden increase in touch pressure due to the Paris wedging phenomenon described above.Moreover, if this phenomenon occurs uniformly for each key, there would be no problem, but in reality, Intertwined with the minute friction mentioned above, it is difficult for elastic deformation to occur uniformly.It is difficult to achieve a stable touch for each thumb key, and variations in the touch feel are likely to occur.Next, Fig. 6 In this case, the rear end of the key 3 is rotatably supported by a horizontal shaft 16, and the key 3 is rubbed more actively.In this case, the friction between the key 3 and the shaft 16 is as described above. Unlike the friction in any of the fulcrum structures, it does not become a defect; on the contrary, it compensates for the defect.
This is because the cross-sectional shape of the hole 17 into which the shaft 16 is inserted is circular, and the key 3 can be smoothly rotated about the shaft 16. In this case, shaft 16 and hole 1
The closer γ is to a perfect circle, the smoother the rotation will be and the better the sliding characteristics can be obtained.

Here, in the fulcrum structure shown in Figs. 1 to 3 and 5, it is possible to provide an arc-shaped sliding surface, but such a sliding surface is extremely difficult and expensive to machine. I'd say it's close to possible. In other words, since the keyboard frame 1 is press-worked, the edges of the insertion holes 6 (see FIGS. 2 and 3) will inevitably have the sagging 9 and burrs 10 shown in FIG. Even if the clearance between the punch and die of the mold is adjusted so that the sag comes out in a semicircular shape, it will only be a part of a perfect circle.

On the other hand, since the aforementioned shaft 16 is formed by cutting or the like, it is technically possible to obtain a shaft close to a perfect circle.

Furthermore, by increasing the precision of the shaft 16 and the hole 1T and making it a so-called rubbing surface, the contact area can be ensured over the entire circumference of the shaft 16, and the friction characteristics can also be improved.

In this way, the fulcrum structure shown in Fig. 6 allows for more stable and smooth key operation than the fulcrum structures shown in Figs. The major drawback is that the work is troublesome.

That is, the key 3 cannot be removed unless the shaft 16 is removed from the key 3 and the bracket 18. Furthermore, since the keys are generally arranged very close to each other, the all-key-shaft method is usually adopted. Therefore, even if one wishes to remove one key 3, it cannot be removed unless the shaft is removed from all the keys, and all the keys fall apart.

Also, when assembling it, it is extremely difficult to assemble it unless all the keys are lined up in reverse order as the shaft will not pass through.

In addition, since all keys are shaft-based, it is difficult to provide the locking function for the horizontal movement of the keys on the shaft, and the side surface of the stand cut into the keyboard frame 1 can be used to prevent horizontal movement. must be regulated and prevented. In this case, since friction occurs not only between the key 3 and the shaft 16 but also between the inner surface of the key 3 and the stand when the key is rotated, it is necessary to consider the frictional characteristics of those parts. Therefore, it has been considered to interpose a washer or the like with good friction characteristics between the key 3 and the stand, but this would increase the number of parts and cause an increase in costs, as well as worsening assembly workability. [Summary of the Invention] This invention has been made in view of the above-mentioned circumstances, and includes a rotation fulcrum member having a circular or arcuate cross-sectional shape disposed on the keyboard frame, By providing a substantially semicircular bearing portion that is pressed against the circumferential surface of the rotation fulcrum member,
An object of the present invention is to provide a keyboard device for an electronic musical instrument that provides stable and good key operation and improves assembly workability.

〔Example〕

The present invention will be described in detail below based on embodiments shown in the drawings.

FIG. 7 is a sectional view showing a first embodiment in which the keyboard device according to the present invention is applied to white keys. In the same figure, 21
is a white key integrally formed from synthetic resin, and the white key 21 is formed by hollowing out the back surface, so that the cross-sectional shape is approximately U-shaped, and the rear end surface 22 has an approximately semicircular shape. A bearing section 23 consisting of four parts is provided.

On the surface of the rear end of the keyboard frame 1, an insertion hole 6 is punched out by pressing or the like, into which an extension 25 extending from the lower surface of the rear end 21A of the white key 21 is inserted. A rotation fulcrum member 26 is fitted and fixed to the rear end edge 6b of this insertion hole 6. The rotation fulcrum member 26 has a circular cross-sectional shape, and the bearing portion 23 is slidably fitted to the outer peripheral surface of the rotation fulcrum member 26, thereby supporting the white key 21 so as to be rotatable in the vertical direction. The rotation fulcrum member 26 is made of plastic or the like, and has a radial fitting groove 27 into which the rear end edge 6b of the insertion hole 6 is fitted. On the other hand, the insertion hole 6
A removal prevention plate 28 is attached to the front edge 6a of the white key 2 so as to partially block the insertion hole 6.
This prevents the extended portion 25 of 1 from coming out of the insertion hole 6.

A substantially hook-shaped stopper 29 is integrally provided vertically on the lower surface of the front end of the white key 21, and a vertical rotation range of the white key 21 is provided on the upper and lower surfaces of the front end 30 of the keyboard frame 1. A lower limit stopper 31 and an upper limit stopper 32 are fixed to each other. A weight 33 is provided on the lower surface of the front end of the white key 21 via a gasket 34. This heavy pad 33 is intended to make the white keys 21 heavier so that the key touch feeling similar to that of a general piano can be obtained, and is detailed in Japanese Patent Application No. 10450/1983 filed earlier by the present applicant. This is a statement. In this case, FIG. 7 shows a state in which the lower surface of the front end of the white key 21 comes into contact with the lower limit stopper 31 due to the key depression operation of the white key 21, and the white key is pressed by the force of the return spring 35, which will be described later. 21
When the rotation returns, the contact surface 29m of the stopper 29 is configured to contact the lower surface of the first upper limit stopper 32.

Further, when the white key 21 is pressed against the return spring 35, an actuator 36 provided integrally with the white key 21 operates a key switch 37 fixed to the back surface of the keyboard frame 1. Thus, the musical tone corresponding to the white key 21 is electrically generated (11-).

A spring holder is integrally provided with a wall 39 near the rear end of the inner surface of the white key 21, and one end 351 of the return spring 35 is locked by the wall 39 of the spring holder. direction,
The other end 35 of the return spring 35 is locked by a locking portion 40 provided on the top surface of the keyboard frame 1.

The return spring 35 is a belt-shaped flat spring formed by punching out a metal plate of an appropriate thickness, and is mounted between the white key 21 and the keyboard frame 1 in a buckled state as shown in the figure. be done.

This is because the spring holder is connected to the locking part 39m of the wall 39 and the keyboard frame 1.
This is because the straight line distance between the locking portion 40 and the return spring 35 is set to be somewhat shorter than the natural length of the return spring 35, so that the return spring 35 is compressed in the longitudinal direction when the white key 21 is attached. The spring 3 undergoes buckling deformation in a horizontal arc shape, and is caused by this deformation.
The reaction force of 5 imparts a clockwise return habit to the white key 21 and presses the bearing portion 23 against the outer periphery of the rotation fulcrum member 26.

Note that 43 is a key guide provided integrally with the keyboard frame 1 to restrict and prevent the white keys 21 from rotating in the left-right direction.

Now, when considering the fulcrum structure of the white key 21 having the above configuration, it can be said that it basically employs relative sliding between a shaft and a hole. However, although a cone generally rotates in the vertical direction, it does not have an extreme angle of displacement;
It is a small angle of about 2 to 5 degrees at most. Furthermore, when the shaft and the hole are in close contact over 360 degrees, the frictional force therebetween is extremely large and prevents smooth sliding, so that only a portion of the shaft and the hole come into contact and slide, and a clearance is created in the other portion. Therefore, in the present invention, the bearing part 23 is formed into a substantially semicircular shape, and is brought into sliding contact with the front half of the rotation fulcrum member 26.

Now, whether the bearing portion 23 and the rotation fulcrum member 26 make rolling contact or sliding contact is determined by the direction of the radial load occurring between them. That is, when the direction of the radial load changes with the rotation of the bearing part 23, the contact part with the rotation fulcrum member 26 moves and performs rolling contact sliding, and when the direction of the radial load does not change, If you simply slide it, it becomes . On the other hand, if a radial load is applied from the direction facing the bearing portion 23, that is, from the rear of the rotation fulcrum member 26, the two will separate and no longer function as a fulcrum. Therefore, if the direction of the radial load is regulated and the bearing part 23 is always in contact with the rotation fulcrum member 26, there is no need to make the bearing part 23 into a hole, whether it is rolling contact or sliding contact. It is possible to provide substantially the same function as the conventional fulcrum structure with a shaft and hole.

Here, to explain the radial load, since the white key 21 is urged backward and diagonally upward by the spring force of the return spring 35, this spring force is the radial load R shown in FIG.
Acts on the rotational fulcrum member as a rotational fulcrum member. This radial load R passes through the center O of the rotation fulcrum member 26 and presses the bearing portion 23 against the rotation fulcrum member 26 . The larger the distance l between the point A on which the radial load R acts and the lower edge Bi of the bearing part 23, the easier the bearing part 23 will slide, and the smaller the coefficient of friction between the bearing part 23 and the rotation fulcrum member 26. Easy to slide. In addition, the larger the intersection angle α between the tangents at points A and B of the rotation fulcrum member 26, the easier it is to slide. In addition,
The distance l is determined by the angle AOB, and ZAOB is α
Since ZAOB is equal to , the larger ZAOB is, the more stable sliding can be obtained. On the other hand, as long as you understand the above theory and select the direction of the radial load R, the setting of ZAOB, the material with a small friction coefficient, etc., it is possible to set the bearing part 23 in an arc shape with an angle smaller than 180°. It is.

Thus, with this kind of fulcrum structure, the same effect as the fulcrum structure with a shaft and hole, that is, good sliding characteristics, can be obtained.
The white key 21 can be rotated smoothly. Further, since the rotation fulcrum member 26 is attached to the through hole 6 provided in the keyboard frame 1 and supports the white key 21, if the removal prevention member 28 is removed, the white key 21 can be inserted into the other key. and can be separately and independently removed from the keyboard frame 1, thereby realizing a single-key key system. Furthermore, the work of attaching and detaching the rotation fulcrum member 26 is easy.

15- By the way, the direction in which the radial load is applied is the white key 2.
Since it changes in accordance with the key press operation 1, the situation will be described in detail based on FIGS. 9 and 10 (i to (a)).

FIG. 9 shows the initial position of the white key 21, and P is the spring pressure exerted by the return spring 35. At this time, the white key 21 is given a return habit with a clockwise moment of P×11 around the center 0 of the rotation fulcrum member 26. When the white key 21 is rotated counterclockwise to its full stroke against the return spring 35, the locking portion 39 of the white key 21 moves to the position C, and the action of the return spring 35 is activated. The direction is the locking part 40
and the point C, and the spring pressure also changes to P'. Therefore, the moment arm becomes 12 and the moment also changes to P'X12. This moment) P'
This creates a playable key.

Next, considering the state in which this white key 21 is to be rotated with a load W, the force applied to the white key 21 is as shown in FIG. These are its own weight W1. Both W and Wl are forces that try to turn the white key 21 counterclockwise, so if the resultant force of these is W2, the forces P and W2 are applied to the white key 21.0 and Since these forces are in equilibrium as moments around the zero point, the resultant force R is always a force directed toward the zero point, which is the radial load mentioned above. On the other hand, if we consider a case where the white key 21 moves to its full stroke and W' is still applied even after it hits the lower limit stopper 31 as shown in FIG. 10(b),
At this time, since the white key 21 receives a counterclockwise rotational moment about the lower limit stopper 31, an upward force R' passing through the zero point is generated.

Since the radial load R was originally acting, the resultant force R' of R and R' will act on the rotation fulcrum member 26. This R' is the radial load when force W' is applied. Therefore, when the position where the force V is applied is shifted between the lower limit stopper 31 and the rotation fulcrum member 26, the directions of the R' and R'' change as shown in FIG. 10(c).

In other words, since the key press position with respect to the white key 21 changes depending on the performance, the direction of the radial load R'' at that time changes within the range of angle θ of 180 or less, as shown in Fig. 11. Therefore, if the bearing portion 23 and the rotation fulcrum member 26 are in minimum contact within the range of the angle θ, the two will not separate, and a fulcrum structure that provides the above-mentioned effects will be constructed.

12(,) to (d) show a second embodiment, in which the rotation fulcrum member 26 is located inside the rear end of the white key 21, the return spring 35 is installed in the opposite direction, and the bearing part 23 is in sliding contact with the rear half of the rotation fulcrum member 26, which is different from the first embodiment. Note that (,) in the same figure shows the spring pressures p and p' of the return spring 35 in the initial position state and at the time of key press operation.
The figure (b) shows the direction of the radial load R due to the spring pressure P and the white key 21's own weight W1, and the figure (e) shows the direction of the white key 2.
The resultant force R of the radial loads R and R' when the force 10-W' is still applied even after pressing 1 to the full stroke and hitting the lower limit stopper 31.
FIG. 3(d) is a diagram showing the direction of the resultant force R'' when the position at which the force W' is applied is shifted rearward from the lower limit stopper 31.

Even in this case, since the direction of the resultant force R' changes within a range of 1800 degrees or less, it is obvious that the bearing portion 23 can be formed into a substantially semicircular shape. In addition, if the bearing part 23 is formed in an arc shape with an angle range of 180 degrees or less, it can be attached to and detached from the rotation fulcrum member 26 freely, and even if the all-key-shaft method is adopted, each weight can be controlled independently. The assembly work efficiency can be greatly improved.

Furthermore, since the direction in which the key can be separated is opposite to the direction of the radial load generated between the key and the rotation fulcrum member 26 during normal performance, the key will never separate during normal performance.
Therefore, stable key press operation is possible.

In addition, since the arc-shaped bearing portion 23 and the rotation fulcrum member 26 do not need to be separated by relative movement in the axial direction,
As shown in Figures 1 and 14, it is possible to add a function to the fulcrum structure itself to restrict and prevent the left and right movement of the key.

That is, FIG. 13 shows a third embodiment of the present invention, in which a plurality of protrusions 51 are integrally provided on the outer periphery of the rotation fulcrum member 26 corresponding to each weight 50, and the bearing portion of the key 50 is 23 is provided with a fitting groove 52 into which the protruding strip body 51 is fitted. In this case, the rotation fulcrum member 26 adopts a full cone-shaft system, and has an integrally hook-shaped leg portion 53, which is fixed onto the keyboard frame 1 with screws. .

On the other hand, in the fourth embodiment shown in FIG. 14, the keyboard frame 1 and the rotation fulcrum member 26 are integrally formed by an outsert molding method, and a plurality of fitting grooves 52 are formed on the outer periphery of the rotation fulcrum member 26. , and a protrusion 51 is formed on the bearing portion 23 of each weight 50.
It has been established.

Note that the rotation fulcrum member 26 integrally has a frame portion 54.

FIG. 15 is a perspective view of a rotation fulcrum member showing a fifth embodiment of the present invention. This embodiment shows a rotation fulcrum member 26 of a one-key, one-shaft type, with an upper semicircular part 20 part 26A and a lower semicircular part 26B having a sufficiently small width.
Both semicircular parts 26A have integral parts.

A groove 60 is provided between 26B and 26B, and the rear end edge 6b of the insertion hole 6 is fitted into the groove 60.

Furthermore, a series of projecting stripes 51 are provided on the surfaces of the upper and lower semicircular portions 26A and 26B to prevent the key from moving in the left-right direction.

FIGS. 16(a) and 16(b) are sectional views of essential parts showing a sixth embodiment of the present invention and views for explaining effects.

This sixth embodiment can also be called a modification of the fifth embodiment shown in FIG. 15, and differs only in that the rear end of the lower semicircular portion 28B is removed. Therefore, the rotation fulcrum member 26
The side surface shape is arcuate over a range of approximately 270 mm. On the other hand, the bearing portion 23 of the key 50 is formed in an arc shape of about 200 degrees.

The reason for this formation is that even if the bearing portion 23 is at an angle of 180° or more, the two can be easily connected and separated. In other words, as shown in FIG.
When 7 is facing downward (or upward), the bearing part 23 is 1
Even though the diameter is more than 800, the interference part can be eliminated due to the dimensional difference in di and d2, so if the rotation fulcrum member 26 is pulled in the direction of arrow 70, it can be easily removed from the bearing part 23. Conversely, when assembling it, it is sufficient to insert it from the direction opposite to the arrow 70. in this case,
The rotation fulcrum member 26 is fitted and fixed into the insertion hole 6 of the rear keyboard frame 1 assembled to the bearing portion 23 of the key 50.

FIG. 17 is a side sectional view of a main part showing a seventh embodiment of the present invention. This embodiment can also be called a modification of the sixth embodiment described above, in which the upper end of the removal stopper piece 71 attached to the back surface of the keyboard frame 1 is connected to the four parts 73 provided on the extended lower surface T2 of the rotation fulcrum member 26. This is to prevent the rotation fulcrum member 26 from coming off the insertion hole 6.

In addition, 5th. Although the sixth and seventh embodiments both show the rotation fulcrum member 26 of the one-key, one-shaft type, it can also be used as an all-key-shaft type if it is formed to a length that extends commonly to all keys. Of course it is possible. Further, in FIG. 17, the removal stopper piece 17 is placed on the cut and raised piece 75, but it may be fixed to the back surface of the keyboard frame 1 with screws.

FIG. 18 is a sectional view showing an eighth embodiment of the invention.

In this embodiment, a rotation fulcrum member 26 having a circular arc surface 80 with a relatively large radius r is used, and the circular arc surface 80 is designed to cover the above-mentioned angular range in which the radial load changes (see FIG. 11). This is what I did. Further, the bearing portion 23 of the key 50 is formed in a circular arc shape corresponding to the circular arc surface 80.

When the radius of curvature r of the rotation fulcrum member 26 is increased, the bearing portion 23 is moved away from the virtual rotation center 0 of the key 50, which has the advantage that the overall length of the key 50 can be shortened by that amount. In addition, a general key is formed long in order to achieve smooth movement and touch feeling, but in this embodiment, a circular arc surface 80 with a large radius of curvature is used to increase the contact area with the bearing part 23. Even though the length of 50 is shortened, it is possible to obtain good and smooth key operation and touch feeling. In addition, the shorter the length of the key 50, the less material is used, which can reduce costs. In addition, the depth dimension of the keyboard frame 1 can also be reduced.

FIG. 19 is a side sectional view showing a ninth embodiment of the present invention. In this embodiment, a bearing part 23 is provided on the lower surface of the middle of the key 50, a recess 90 is provided on the lower part of the rear end surface, and the rear end edge 91m of a hole 91 provided in the keyboard frame 1 is inserted into this recess 90 without contact. It is. The center of rotation of the key 50 is the recess 90
It is located in the center of The radial load R during normal key press operation is received by the rotation fulcrum member 26, and the radial load R' or R'' generated by pressurization even after the key press operation is applied.
is received by the recess 90 and the rear end edge 91m. in this case,
Since the key 50 is no longer rotating when R' or R'' occurs, there is no need to give special consideration to the friction characteristics, shape, etc. of the recess 90 and the rear end 911L.

Even in such a configuration, the rotation fulcrum member 26 and the bearing portion 2
It will be clear that the key 50 operates well and smoothly by sliding with the key 3, thereby improving the touch feeling.

〔Effect of the invention〕

As explained above, in the keyboard device for an electronic musical instrument according to the present invention, a circular or fan-shaped rotational fulcrum member is disposed on the keyboard frame, and a substantially semicircular bearing portion is provided on the key that slides in contact with the rotational fulcrum member. Since the fulcrum structure based on these contact and sliding movements is adopted, the key operation can be performed smoothly and a good touch feeling can be obtained. In addition, it is easy to attach and remove the key from the rotational fulcrum member, and there is no need to worry about bumps or cracks, which makes it possible to use not only the all-key-shaft method but also the single-key, single-shaft method, which increases the durability of the sliding surface. Its effects are extremely large, such as being able to prolong the lifespan of musical instruments.

In addition, if a weight is provided on the lower surface of the front end of the key, an even better touch feeling can be obtained.

[Brief explanation of drawings]

Figures 1 to 3 are side views, sectional views, and side sectional views of main parts showing the fulcrum structure of a conventional keyboard device, and Figure 4 (a) (
Fig. 5 and Fig. 6 are side views of main parts showing the fulcrum structure of a conventional keyboard device, and Fig. 7 shows a first embodiment of the keyboard device according to the present invention. Figure 8 is a diagram showing the radial load, Figure 9 is a diagram showing changes in the spring pressure of the return spring, and Figures 10 (,) to (C) are diagrams showing changes in the direction of the radial load. , Fig. 11 is a diagram showing the range of change in radial load, Fig. 12 is a diagram showing the second embodiment, (a) is a diagram showing changes in spring pressure, (b) + (c) + (d) 13 is a perspective view of a rotation fulcrum member and a bearing portion showing a third embodiment of the present invention, and FIG. 14 is a perspective view of a rotation fulcrum member and a bearing portion showing a fourth embodiment of this invention. A perspective view of a fulcrum member and a bearing part, FIG. 15 is a perspective view of a rotating fulcrum member showing a fifth embodiment of the present invention, and FIG. 16(') l (b) shows a sixth embodiment of the present invention. 17 is a side sectional view of essential parts showing a seventh embodiment of the invention; FIG. 18 is a sectional view showing an eighth embodiment of the invention; FIG.
The figure is a side sectional view of a main part showing a ninth embodiment of the invention. 1...Keyboard frame, 21...Black keys, 23...
... Bearing part, 26 ... Rotation fulcrum member, 35 ...
Return spring, 50...Key 0 Patent applicant Nippon Gakki Mfg. Co., Ltd. agent Masaki Yamakawa (□) 1 person) (Riki ＾ Tanane ＾ 0

Claims (1)

[Claims] A key disposed on a keyboard frame so as to be swingable in the vertical direction, and a return spring for imparting a return habit to the key, and a turn having a circular or arcuate cross-sectional shape on the keyboard frame. An electronic device characterized in that a movable fulcrum is provided, and a substantially semicircular bearing portion is provided at the rear end of the key to slidably abut on a surface of the rotary fulcrum member and is pressed against by the return spring. A musical instrument keyboard device.