JPH0446312Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a key device for an electronic keyboard instrument such as an electronic piano.

(Prior Art) As shown in FIG. 6, a conventional device of this type has one end of a U-shaped leaf spring a connected to the back end c of a key b.
Another known method is to have the other end hooked to the chassis d to obtain the return force for the key b.

(Problems to be Solved by the Invention) However, according to the above conventional device, as shown in FIG. 7, the static touch characteristic of the key does not become a hysteresis characteristic, that is, the key touch when operating the key Since there is no hysteresis characteristic in the row load and return load, when you press down on a key with your fingers, if you weaken the force of your fingers even a little, the key will rise, making it easy for the key to wobble during play, and it will cause problems such as piano touch. This creates an inconvenience that makes subtle expression difficult.

In addition, the equivalent mass of the keys is small, and as shown in FIG. 7, the dynamic touch characteristics of the keys are smaller than those of a piano, resulting in the inconvenience that there is no response when the keys are pressed like on a piano.

Furthermore, it is necessary to remove the leaf spring when removing the key.
Moreover, there is an inconvenience that requires skill to attach and detach the leaf spring.

The object of the present invention is to eliminate the disadvantages of the conventional devices described above.

(Means for Solving the Problems) In order to achieve the above object, the present invention fits a groove of a rotating shaft into a substantially horizontal or vertical locking part of a chassis, and a recess of a rotor is fitted to the rotating shaft. are fitted to make the rotor rotatable, one end of the rotor is brought into contact with the rear end of the fulcrum of the key, and a heavy mass is placed at the other end located across the center of rotation of the rotation shaft with respect to the one end. form,
A key return spring is provided between the rotor and the chassis, and a stopper portion is formed on the chassis to prevent the rotor from swinging, so that when the key is pressed or released, one end of the rotor is fixed. The key is characterized in that a rear end of the fulcrum of the key is slid to generate a frictional force between the rotor and the key, and a frictional force is generated between the rotating shaft and the recessed portion of the rotor. .

(Function) The present invention has the above configuration, and according to this, when the key is pushed in with a finger, there is a gap between the rear end of the fulcrum of the key, one end of the rotor, the wall surface of the recess of the rotor, and the rotating part. Since a frictional force acts in the same direction as the spring force, the fourth
As shown by X in the figure, the touch load on the key becomes heavier.

Conversely, when the key is returned to its original position, the frictional force acts in the opposite direction to the spring force, so the touch load on the key becomes lighter, as shown by Y in FIG.

In this way, the static touch characteristic of the key becomes a hysteresis characteristic. Furthermore, since the heavy mass part is formed at the other end of the rotor, the equivalent mass of the key becomes large, and the dynamic touch characteristics of the key can be made closer to those of a piano, as shown by Z in FIG.

Furthermore, the key can be removed by simply pulling the rotor and rotating shaft slightly toward the rear of the key.

(Example) Examples of the present invention will be described below based on the drawings.

1 and 2, reference numeral 1 indicates a chassis fixed to a shelf board 2, a rotating shaft 3 is locked to the chassis 1, and a rotor 4 is fitted in the recess 5 of the rotating shaft 3. combined and made rotatable.

One end of the rotor 4 contacts the upper surface of the fulcrum rear end 7 of the key 6, and a heavy mass portion 8 is formed at the other end located across the center of rotation of the rotor 3 from the one end.

A coil spring 9 for key return is stretched between the rotor 4 and the chassis 1.

To explain the above structure in more detail, as shown in FIG. It consists of a stopper part 12 horizontally installed below the rotor 4 and an L-shaped fixing part 13 which is a separate member from these. A plurality of windows 14 are formed into which the stopper 12 is inserted.
is provided with a cushioning material 15 such as felt.

The spring load can be adjusted by tilting the spring receiving portion 11 back and forth. The rotating shaft 3 has a circumferential surface formed in a circular button shape over most of its circumferential surface, and has a groove 16 for engaging the chassis 1.

The rotor 4 has a recess 5 coated with a lubricant such as grease in the middle part of the upper surface and fits into the rotating shaft 3, and the lower surface of one end of the recess 5 allows the key 6 to smoothly contact the upper surface of the rear end 7 of the fulcrum. A groove 17 in which one end of the spring 9 is locked is formed on the upper surface of the other end, and a weight 18 is attached by adhesive or the like to the lower surface of the other end to form the heavy mass part 8. There is.

In FIG. 2, reference numeral 19 denotes a vibration isolator made of, for example, sponge, which is bonded to the upper surface of the rotor 4 in order to prevent the vibration of the spring 9, and 20 denotes a retainer that fits into the groove 16 of the rotary shaft 3. The stop portions 21 and 22 represent, for example, a Teflon tape and an elastic material underneath, which are pasted so that the rotor 4 can slide smoothly.

The key 6, rotor 4, and coil spring 9 are configured as follows in order to reduce the increase in key touch load with respect to the key stroke, eliminate the feeling of pressure on the fingers during playing, and make playing easier. Relationships are selected.

In FIG. 3, A is the fulcrum of the key 6, B is the contact point between the rotor 4 and the key 6, C is the center of rotation of the rotor 4, and D
is the point of action of the coil spring 9 on the rotor 4, E is the center of gravity of the rotor 4, and G is the locking point of the coil spring 9 on the chassis 1.

The condition that the touch load on the key 6 does not increase is F ₁ l ₁ ≧F ₁ ′l ₁ ′ …(1) However, F ₁ l ₁ and F ₁ ′l ₁ ′ are the key rotation before and after the key stroke. moment, strictly speaking, F ₁ l ₁ ≒
However, in reality, there is a slight increase in the load due to a keyboard switch (not shown), so taking this into account, _{F 1 l 1 >} F ₁ 'l ₁ ' is also included.

Before the stroke of the key 6, from the balance of moments around the rotation center C of the rotor 4, F ₂ l ₂ = F ₃ l ₃ −F ₄ l ₄ …(2) Here, F ₃ = F cos θ ₃ , F ₄ = mg cos θ ₄ (F; spring force of coil spring (9)) Since the normal force of the rotor 4 and the normal force of the key 6 are equal, F ₁・1/cos θ ₁ = F ₂・1 /cos θ ₂ …(3) holds true.

From equation (3), F ₁ = cos θ ₁ / cos θ ₂・F ₂ = (Fl ₃ cos _{θ 3} − mgl ₄ cos θ ₄ )/l ₂ cos θ ₂ cos θ ₁ …(4) Equation (4) is Since it holds even after the stroke, F ₁ ′= (F′l ₃ ′cos θ ₃ ′−mgl ₄ ′cos θ ₄ ′)/l ₂ ′cos
θ ₂ ′・cos θ ₁ ′…(4)′ Comparing equations (4) and (4)′, l ₂ ≒l ₂ ′, l ₃ ≒l ₃ ′l ₄ ≒l ₄ ′ l ₁ ≒l ₁ ′, so in order for F ₁ ≒ F ₁ ′, F l ₃ cos θ ₃ −mg l ₄ cos θ ₄ )/cos θ ₂・cos
θ ₁ = (F′l ₃ ′cos θ ₃ ′−mg l ₄ ′cos θ ₄ ′)/cos
It is necessary that the relationship θ ₂ ′・cos θ ₁ ′ hold.

That is, F′>F, θ ₁ ′≧θ ₁ , θ ₂ ′≦θ ₂ , θ ₃
′≧
The fulcrum A of the key ₆ , the contact point B between the rotor ₄ and the key ₆ , the center of rotation C, the point of action D of the coil spring 9, and the rotor so as to satisfy some of the angle conditions of θ 3 , θ 4 ′≦θ 4 By arranging the center of gravity E of the coil spring 4 and the locking point G of the coil spring 9, the increase in key touch load is reduced.

In this case, when the key 6 is pushed in with a finger, the sliding friction force caused by one end of the rotor 4 sliding on the Teflon tape at the rear end 7 of the fulcrum of the key 6, and the friction between the rotor 4 and the rotating shaft 3. The viscous frictional force caused by the lubricant between the two acts in the same direction as the spring force, as shown by the solid arrow in FIG. When the key is returned to its original position, both frictional forces act in the direction opposite to the spring force, as shown by the dashed arrows in Figure 1, in other words, to weaken the returning force of the key due to the spring force. It becomes heavier when moving (going forward) and lighter when releasing the key (returning), and the static touch characteristic of key 6 has a hysteresis characteristic similar to that of a piano.

Further, when the key 6 is pressed, the rotor 4 rotates around the rotating shaft 3, and the weight 18 also rotates. At this time, weight 18
Due to the inertia of the rotor 4, the rotor 4 starts rotating later than the key 6. From this, the finger pressing the key 6 feels a large reaction force due to the inertial mass of the weight 18. This is almost similar to the reaction force that occurs when an action hammer acts behind the key when the key is pressed on a piano, and the dynamic touch characteristics of the key 6 are similar to those of a piano.

Furthermore, when the key 6 is pressed in, the other end of the rotor 4 hits the cushioning material 15 of the stopper part 12, so that the vibration of the rotor 4, which has a large inertial mass, is immediately suppressed, and the finger pressing the key 6 is not affected. In addition, the rotation range of the rotor 4 is controlled so that the key 6 and the rotor 4 are always interlocked.
It has been designed to have an effect similar to that of a piano's back check, which improves the performance of repeated hits.

In addition, when the key 6 is to be removed, it is possible to do so by simply pulling out the rotor 4 and the rotating shaft 3 slightly toward the rear of the key 6 without removing the spring 9.

FIG. 5 shows another embodiment of the present invention, in which the upright portion 10 and fixed portion 13 of the chassis 1 are made of the same material, and one end of the coil spring 9 is attached to the upper surface of one end of the rotor 4. Although the heavy mass part 8 was formed by locking the rotor 4 and attaching a weight 18 to the upper surface of the other end of the rotor 4, the operation and effect thereof are not particularly different from those of the embodiment shown in FIGS. 1 and 2, so a description thereof will be omitted.

In the two embodiments described above, since the spring is formed of a coil spring 9, high dimensional accuracy can always be obtained and the touch load of the key 6 does not vary. Since it is composed of springs, the dimensional accuracy tends to decrease during manufacturing and assembly operations, and the touch load of the key varies, as in the conventional example. This has the effect of eliminating the inconvenience of having to adjust the bending angle, which is troublesome, time-consuming, and requires skill.

In addition, since the spring force of the coil spring 9 acts in the direction in which the rotor 4 rotates, the restoring force of the leaf spring always acts to push the fulcrum in the direction of the fulcrum of the key. This has the effect of not causing the disadvantage that the related dimensions change over time.

(Effects of the invention) As described above, when the present invention is used, the increase in key touch load with respect to the key stroke is small, and the static touch characteristics and dynamic touch characteristics of the keys, which are similar to those on a piano, can be obtained. It has the effect of making it possible to produce a touch expression that is very similar to that of a piano, by providing a firm yet firm response.

In addition, the key can be removed simply by pulling out the rotor and rotating shaft to the rear of the key, which has the effect of simplifying the key removal operation compared to the conventional method in which the leaf spring must be removed.

Furthermore, when the key is pushed in, the operating energy of the rotor can be absorbed by the stopper portion, and free vibration of the rotor can be suppressed, which has the effect of improving the performance of repeatedly hitting the key.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an example of the implementation of the present invention, FIG. 2 is an exploded perspective view of the main parts, FIG. 3 is an explanatory diagram for obtaining conditions for reducing the increase in key touch load, and FIG. Fig. 4 is a key touch load/key stroke characteristic diagram, Fig. 5 is a side view showing another embodiment of the present invention, Fig. 6 is a side view of a conventional key device, and Fig. 7 is a key touch load/key stroke characteristic diagram. It is a key stroke characteristic diagram. 1... Chassis, 3... Rotating shaft, 4... Rotor, 5... Recess, 6... Key, 7... Rear end of fulcrum, 8
...Heavy mass part, 9...Key return spring, 12...Stopper part.

Claims (1)

[Scope of utility model registration request] The groove of the rotating shaft is fitted into the substantially horizontal or vertical locking part of the chassis, and the recess of the rotor is fitted to the rotating shaft to make the rotor freely rotatable, and one end of the rotor is set as the fulcrum of the key. forming a heavy mass part at the other end that is in contact with the rear end and located across the center of rotation of the rotating shaft with respect to the one end, and a key return spring is stretched between the rotor and the chassis; Furthermore, a stopper part for suppressing vibration of the rotor is formed on the chassis, and when a key is pressed or released, one end of the rotor slides on the rear end of the fulcrum of the key, and is moved between the rotor and the key. generates a frictional force in
A key device for an electronic keyboard instrument, characterized in that a frictional force is generated between the rotating shaft and a recessed portion of the rotor.