JP3358205B2 - Key drive for automatic performance piano - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a key drive device for playing a piano by automatically pushing up the keys of the piano.

[0002]

2. Description of the Related Art Conventional techniques include, for example,
There is a key drive device shown in 2-149094, in which a collision type solenoid is staggered in a common yoke. FIG. 7 is a sectional view showing the configuration of the key driving device.

In this drawing, a common yoke 2 formed in a substantially U-shape is disposed in a key driving device 1 below a rear end portion of keys 3 so as to be substantially parallel to the lower surface of the keys. Have been. Inside the common yoke 2, solenoids 4A, 4
B are arranged in a zigzag pattern corresponding to the keys 3 and 3, respectively. The solenoid 4A is provided in the front row (front side of the piano), and the solenoid 4B is provided in the rear row. These solenoids 4A and 4B drive a plunger (not shown) by supplying a drive current. At this time, the rear end of the key 3 corresponding to the solenoid 4A is pushed up by being pushed by a push-up button 5A provided at the upper end of the plunger, and the rear end of the key 3 corresponding to the solenoid 4B is located at the upper end of the plunger. It is pushed up by being pushed by the push-up button 5B provided. When a hammer linked to each key strikes a string (not shown), a corresponding musical tone is emitted.

[0004]

However, in the above-described key driving device for an automatic performance piano, a collision type solenoid is used, so that the following problems have occurred.

FIG. 8 shows a thrust (stroke to plunger) characteristic of a solenoid of a conventional key driving device. In this figure, the horizontal axis represents the stroke of the plunger, and the vertical axis represents the thrust of the solenoid. In the conventional key drive device, as shown in FIG. 8, the thrust (stroke to plunger) characteristic of the solenoid is not smooth. However, since the thrust is largely displaced in accordance with the displacement of the plunger, there is a problem that it is difficult to use the key drive.

[0006] In addition, solenoids 4A and 4
Since the distance from B is small, magnetic interference may occur between the solenoids adjacent to each other, and the operation of the plunger may be irregular. For example, if the winding directions of the adjacent solenoid wires are the same, the thrusts are mutually weakened, and conversely, if the winding directions of the adjacent solenoid wires are different, the thrusts are mutually strengthened, and the keying strength is accurately adjusted. There was a problem that playback was not possible.

Further, when the solenoid is operated, a problem arises in that a collision sound between the plunger and the yoke 2 is generated and noise is generated. A way to alleviate this was taken. However, in this method, the collision sound cannot be completely eliminated, and the structure becomes complicated, so that the plunger stroke position where the solenoid can obtain the most thrust cannot be used to prevent the collision portion. .

The present invention has been made in view of the above circumstances, and all plungers can obtain a sufficient thrust corresponding to the key at the initial stage of each drive, and magnetic interference between adjacent solenoids can be obtained. To provide a key drive device for an automatic performance piano, which can prevent irregularities in the operation of the plunger due to the above and can prevent the collision sound (noise) between the plunger and the yoke with a simple configuration. I have.

[0009]

In order to solve the above-mentioned problems, according to the first aspect of the present invention, a plurality of penetrating solenoids penetrating a plunger are arranged in a staggered arrangement on a common yoke capable of magnetically shielding. A key drive device for a piano, wherein the common yoke includes a plurality of yoke portions disposed above the solenoid and a portion disposed below the solenoid, and each of the plurality of yoke portions is It is provided in common for at least some of the plurality of solenoids, has a plurality of openings that penetrate the plunger, and staggers the solenoids on one yoke and attaches the other yoke around the solenoid. And a plunger having a larger diameter than the opening of the yoke portion disposed above the solenoid. Provided with a Jaheddo, characterized in that it is inserted to allow the respective solenoids extraction above the yoke disposed in said upper.

[0010]

According to the first aspect of the present invention, since a plurality of penetrating solenoids are used and a common yoke capable of magnetically shielding is provided, the thrust (stroke with respect to the plunger) characteristic is smoothed and an appropriate keying strength is obtained. Is obtained. Further, when the solenoid is not operated, the plunger head comes into contact with the yoke disposed above the solenoid, so that the plunger inserted into the solenoid does not drop. And
When the solenoid is actuated, even if the plunger moves upward, there is no object other than the key to collide, so at the same time as the piano sound generated by the plunger pushing the key,
It is possible to prevent the generation of an extra collision sound. Further, since the position of the plunger with respect to the common yoke is determined only by inserting the plunger into each opening of the yoke portion, the mounting of the plunger becomes easy.

[0011]

Next, an embodiment of the present invention will be described with reference to the drawings. In the drawings shown below, portions corresponding to those in FIGS. 7 and 8 are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 1 is a sectional view showing the structure of an embodiment of the present invention. In this figure, solenoids 11A, 1
1B corresponds to the adjacent keys 3 and 3, respectively, and is provided in the front row (the front side of the piano) and the rear row, respectively. The periphery is covered by the upper yokes 12A and 12B.

The solenoids 11A and 11B are
It is configured by winding a conductive wire around A, 13B. Then, inside the bobbins 13A, 13B, the plungers 14A, 14B are movable so as to be able to reciprocate. The plungers 14A, 14
Plunger heads 16A and 16B are connected to the upper part of B through plunger shafts 15A and 15B.
The diameter of the plunger heads 16A and 16B is the bobbin 13A,
Since it is larger than the through hole of 13B and the opening diameter of the upper yokes 12A and 12B, the plungers 14A and 14B stop at the illustrated positions when not driven.

In addition, cushion felts 17A and 17B are provided below each of the plunger heads 16A and 16B to absorb the impact of the plunger heads 16A and 16B with the upper yokes 12A and 12B.

FIG. 2 shows the above-mentioned solenoids 11A and 11A.
FIG. 2 is a cross-sectional view taken along line AA ′ of FIG. In this figure, solenoids 11A, 11B,
, 11B, 11A are arranged in a staggered arrangement, and are attached to the lower yoke 18 in correspondence with the keys 3, 3, ..., 3, 3. Also, the upper yokes 12A, 12A
By dividing B,..., 12A, and 12B into low, middle, and treble parts, maintainability is improved, and
In order to be able to adjust the height of the lower yoke 18, the lower yoke 18 has a flexible structure. If the front row and the rear row are set at the same position, the division positions of these bass, middle, and treble parts are too weak in structure, so they are shifted as shown in FIG. 2 in order to obtain a predetermined strength.

The adjusting screws 19, 19 are located between the position where the upper yoke 12A is divided into a low-frequency portion and the middle frequency portion and the position where the upper yoke 12B is divided into a low-frequency portion and a medium frequency portion. One location, two locations in the middle between the location where the upper yoke 12A is divided into a mid-tone section and a treble section and the location where the upper yoke 12B is divided into a mid-tone section and a treble section It is provided in.

Further, as shown in FIG.
Are mounted on a mounting bracket 20 connected to a piano frame via springs by adjusting screws 19 and 19. Therefore, when the adjustment screw 19 is turned, the key driving device 1
0 moves up and down with reference to the mounting bracket 20. Therefore, the initial keying height of the plunger 14 (the distance between the lower surface of the keyboard and the upper surface of the plunger head) can be freely changed.

As shown in FIG. 1, a drive board 21 is mounted on a board mounting bracket 22 below the key driving device 10. When driving a selected key, the solenoid 1
A drive current is supplied to 1A or 11B. The board mounting bracket 22 also serves as a stand for the key drive device 10, and prevents the key drive device 10 from falling over even when placed alone.

FIG. 4 is a perspective view of the key driving device 10. In this drawing, the lower yoke 18 has slits 23A and 23A.
3B is provided through the lead wires 24A, 24A.
B is a slit 23A from the solenoids 11A and 11B,
It is connected to the drive board 21 through 23B. The above-described drive current is supplied to the solenoids 11A and 11B via the lead wires 24A and 24B.

Next, a description will be given of a process in which the keys 3 and 3 of the piano are pushed up by the key driving device 10 and corresponding musical sounds are emitted in the above-described configuration.

In FIG. 1, when drive current is supplied to the solenoids 11A and 11B by the drive board 21, the plungers 14A and 14B are moved to the bobbins 13A and 13B.
Inside B, it is driven upward. As described above, when the plunger 14A or 14B is driven, the corresponding keys 3, 3 are pushed up from below on the plunger heads 16A, 16B, and the corresponding piano musical sound is emitted. Then, when the supply of the drive current to the solenoids 11A and 11B is stopped, the plungers 14A and 14B return to their original positions. At this time, the plunger heads 16A and 16B
The upper yokes 12A, 12B are provided via cushion felts 17A, 17B provided as cushioning materials below the upper yokes.
As a result, it is possible to return to the original position quietly without generating a collision sound. Furthermore, the volume and other elements on the drive board 21 can be adjusted from the front of the piano,
Excellent maintainability.

Further, since the solenoids 11A and 11B are of the penetrating type, the thrust (stroke with respect to the plunger) characteristic of the solenoid shown in FIG. 5 is smoothed as compared with the conventional one shown in FIG. Therefore, the range of the stroke of the plunger in which the solenoid can obtain a substantially constant thrust is widened. In addition, the plunger 1 is fixed by two adjusting screws 19,19.
Since the height positions of 4A, 14B,..., 14B, 14A can be changed, plungers 14A, 14B,.
It can be adjusted to a position where the thrust of 4B and 14A works effectively.

The front row and rear row solenoids 11A,
If the intervals of 11B are sufficiently large, irregularities in the operation of plungers 14A and 14B due to magnetic interference can be prevented, so that upper yoke 25 is not divided and shared, as shown in FIG. good.

[0024]

As described above, according to the first aspect of the present invention, since the through solenoid is used,
The thrust (stroke to plunger) characteristic of the solenoid is smoothed. Therefore, the thrust of the solenoid can be effectively used for keying. Further, since the common yoke capable of magnetic shielding is provided for the plurality of solenoids, irregularities in the operation of the plunger due to magnetic interference between adjacent solenoids are prevented. As a result, the advantage that the keying strength can be accurately reproduced can be obtained. Further, since this key driving device has a configuration in which the plunger which can be taken out is provided above the penetrating solenoid, it is possible to prevent the generation of an extra collision sound with a simple configuration. Further, since the position of the plunger with respect to the common yoke is determined only by inserting the plunger into each opening of the yoke portion, the mounting of the plunger becomes easy.

[Brief description of the drawings]

FIG. 1 is a sectional view of a key driving device showing a configuration of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line A-A 'of FIG.

FIG. 3 is a cross-sectional view showing attachment of the key driving device 10 shown in FIG.

FIG. 4 is a perspective view of the key driving device 10 shown in FIG.

FIG. 5 is a diagram showing a thrust (stroke to plunger) characteristic of the solenoid 11 shown in FIG.

FIG. 6 is a sectional view showing a configuration of another embodiment of the present invention.

FIG. 7 is a cross-sectional view showing one configuration of a conventional key driving device.

8 is a diagram showing a thrust (stroke to plunger) characteristic of the solenoid 4 shown in FIG.

[Explanation of symbols]

3 ... key, 10 ... key drive device, 11A, 11B ...
... Solenoid, 12A, 12B ... Upper yoke, 13
A, 13B ... bobbin, 14A, 14B ... plunger, 15A, 15B ... plunger shaft, 16
A, 16B ... Plunger head, 17A, 17B ...
... cushion felt, 18 ... lower yoke, 19 ...
... Adjustment screw, 20 ... Mounting bracket, 21 ... Drive board, 22 ... Board mounting bracket

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-B-48-33689 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) G10F 1/02 G10F 5/02

Claims (1)

(57) [Claims] 1. A key drive device for an automatic performance piano in which a plurality of penetrating solenoids for penetrating a plunger are arranged in a staggered manner on a common yoke capable of magnetically shielding, wherein the common yoke is disposed above the solenoid. And a plurality of yoke portions disposed below the solenoid, wherein the plurality of yoke portions are provided in common for at least some of the plurality of solenoids, and a plurality of the yoke portions penetrate the plunger. An opening is provided, and a solenoid is staggered and mounted on one yoke, and the other yoke is provided so as to cover the periphery of the solenoid. The plunger is disposed above the solenoid. A plunger head having a diameter larger than the opening is provided, and the plunger head is taken out above a yoke disposed above the plunger head. Capable lock driving device for an automatic player piano, characterized in that it is inserted into the solenoids.