JPH05281959A - Device for driving key of automatic playing piano - Google Patents

Abstract

PURPOSE:To smooth the thrust (stroke to a plunger) characteristics of a solenoid for an automatic piano, to prevent the plunger from operating disorderly owing to magnetic interference with a nearby solenoid, and to prevent the plunger and a yoke from generating a collision sound (noise) with simple constitution. CONSTITUTION:Through type solenoids 11A and 11B which have smooth thrust (stroke to the plunger) characteristics are arrayed zigzag between upper yokes 12A and 12B and a lower yoke 18; and the magnetic interference between the respective contiguous solenoids 11A and 11B is prevented by the upper yokes, and cushion felt is interposed between the plunger heads 16A and 16B and upper yokes to prevent the collision sound.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art As a conventional technique, for example, the actual development 6
There was a key drive device shown in No. 2-149094 in which collision type solenoids were arranged in a zigzag pattern on a common yoke. FIG. 7 is a sectional view showing the structure of the lock driving device.

In this figure, a key driving device 1 is provided with a common yoke 2 bent in a substantially U-shape and disposed below the rear ends of the keys 3 and 3 so as to face the lower surface of the key substantially in parallel. Has been done. Inside the common yoke 2, solenoids 4A, 4
Each B is arranged in a zigzag pattern corresponding to the keys 3 and 3. The solenoids 4A are provided in the front row (front side of the piano), and the solenoids 4B are provided in the rear row. These solenoids 4A and 4B drive a plunger (not shown) by being supplied with a drive current, respectively. At this time, the rear end of the key 3 corresponding to the solenoid 4A is pushed up by the push-up button 5A provided on the upper end of the plunger, and the rear end of the key 3 corresponding to the solenoid 4B is moved to the upper end of the plunger. It is pushed up by being pushed by the push-up button 5B provided. Then, a hammer interlocking with each key strikes a string (not shown) to produce a corresponding musical sound.

[0004]

By the way, in the above-mentioned key driving device of the automatic playing piano, since the collision type solenoid is used, the following problems occur.

FIG. 8 shows a thrust (a plunger stroke) 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 force of the solenoid. In the conventional key drive device, as shown in FIG. 8, the thrust force of the solenoid (against the stroke of the plunger) is not smooth. However, since the thrust force is largely displaced according to the displacement of the plunger, there is a problem that it is difficult to use for driving the lock.

Further, the solenoids 4A and 4 are arranged in a staggered arrangement.
Since the distance from B is narrow, magnetic interference may occur between solenoids that are close to each other, and the operation of the plunger may be irregular. For example, when the winding directions of the conducting wires of the adjacent solenoids are the same, the thrusts are weakened each other.On the contrary, when the windings of the conducting wires of the adjacent solenoids are different, the thrusts are mutually strengthened and the keystroke strength is accurate. There was a problem that it could not be played.

Further, when the solenoid operates, there is a problem that a collision sound between the plunger and the yoke 2 is generated and becomes a noise. Therefore, by inserting a felt piece or the like between the plunger and the yoke 2, a collision sound is generated. The method of alleviating was taken. However, this method has a problem that the collision sound cannot be completely eliminated, the structure is complicated, and the stroke position of the plunger 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-mentioned circumstances, and all the plungers can obtain a sufficient thrust corresponding to the key at the initial stage of each driving, and the magnetic interference between the adjacent solenoids. With the aim of providing a key driving device for an automatic playing piano, it is possible to prevent irregular movements of the plunger due to the movement of the plunger and to prevent collision noise (noise) between the plunger and the yoke with a simple configuration. There is.

[0009]

In order to solve the above-mentioned problems, in the present invention, in a key driving device for an automatic playing piano in which a plurality of solenoids are arranged in a staggered manner on a common yoke, the plurality of solenoids are penetrating type. A common yoke capable of magnetically shielding is provided to the plurality of solenoids.

[0010]

Since a plurality of through-type solenoids are used and a common yoke capable of magnetically shielding is provided, the thrust (stroke with respect to the plunger) characteristics are smoothed, collision noise is not generated, and proper keystroke strength is obtained. ..

[0011]

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

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

The solenoids 11A and 11B are the bobbin 13
It is configured by winding a conductive wire around A and 13B. The plungers 14A and 14B are movable inside the bobbins 13A and 13B so that they can reciprocate. The plunger 14A, 14
Plunger heads 16A and 16B are connected to the upper part of B through plunger shafts 15A and 15B.
The diameters of the plunger heads 16A, 16B are the bobbin 13A,
Since the through holes of 13B and the opening diameters of the upper yokes 12A and 12B are larger, the plungers 14A and 14B stop at the positions shown in the drawing when not driven.

Cushion felts 17A and 17B are provided at the bottom of each of the plunger heads 16A and 16B to absorb the impact with the upper yokes 12A and 12B due to the drop of the plunger heads 16A and 16B.

FIG. 2 shows the solenoids 11A and 11 described above.
FIG. 2 is a cross-sectional view taken along the line AA ′ in FIG. 1, showing a position where B is arranged on the lower surface of the key. 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 ,. Also, the upper yokes 12A, 12
By dividing B, ..., 12A, 12B into low-pitched part, mid-pitched part, and high-pitched part, maintainability is improved and
In order to adjust the height of the lower yoke 18, it has a structure that is easily bent. The dividing positions of the low-pitched sound portion, the middle-pitched sound portion, and the high-pitched sound portion are structurally too weak when the front row and the rear row are arranged at the same position, and are thus shifted as shown in FIG. 2 in order to obtain a predetermined strength.

The adjusting screws 19 and 19 are located between the position where the upper yoke 12A is divided into the low-pitched portion and the middle-tone portion and the position where the upper yoke 12B is divided into the low-pitched portion and the middle-tone portion. 1 place, 1 position in the middle of the position where the upper yoke 12A is divided into the mid-tone part and the high-pitched part and the position where the upper yoke 12B is divided into the mid-tone part and the high-pitched part, 2 places in total It is provided in.

Further, as shown in FIG. 3, the lock driving device 10
Is installed on a mounting bracket 20 that is connected to the piano frame via a spring by adjusting screws 19 and 19. Therefore, when the adjusting screw 19 is turned, the lock driving device 1
0 moves up and down based on the mounting bracket 20. Therefore, the initial keystroke 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.

At the lower part of the lock driving device 10, as shown in FIG. 1, a drive board 21 is attached to a board mounting bracket 22. 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 of the lock driving device 10, and prevents the board mounting bracket 22 from tipping over even when mounted alone.

FIG. 4 is a perspective view of the lock driving device 10, in which the lower yoke 18 has slits 23A and 2A.
3B are provided so as to penetrate therethrough, and lead wires 24A, 24
B is a slit 23A from the solenoid 11A, 11B,
It is connected to the drive board 21 through 23B. The drive current described above is supplied to the solenoids 11A and 11B by 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 in the above-mentioned structure and a corresponding musical sound is emitted.

In FIG. 1, when drive current is supplied to the solenoids 11A and 11B by the drive board 21, the plungers 14A and 14B move to the bobbins 13A and 13B.
Driven upwards inside B. In this way, when the plunger 14A or 14B is driven, the corresponding keys 3 and 3 are pushed up by the plunger heads 16A and 16B from below, and the corresponding musical sound of the piano 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 are
Upper yokes 12A, 12B are provided through cushion felts 17A, 17B provided as cushioning materials under the upper yokes 12A, 12B.
Since it is stopped at, it is possible to return to the original position quietly without making a collision sound. Furthermore, elements such as the volume 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 through type, the thrust force (stroke of 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 stroke of the plunger in which the solenoid can obtain a substantially constant thrust is expanded. In addition, the plunger 1 is adjusted by the two adjusting screws 19 and 19.
Since the height positions of 4A, 14B, ..., 14B, 14A can be changed, the plungers 14A, 14B ,.
It can also be adjusted to a position where the thrust of 4B and 14A works effectively.

Further, the solenoids 11A in the front row and the rear row,
When the distances of 11B are sufficiently separated, the irregularities of the movements of the plungers 14A and 14B due to magnetic interference are prevented, so that the upper yoke 25 is not divided but is made common as shown in FIG. good.

[0024]

As described above, according to the present invention, since the penetrating solenoid is used, the thrust force (stroke with respect to the plunger) of the solenoid is smoothed. Therefore, the thrust of the solenoid can be effectively used for keying. Further, since the common yoke capable of magnetically shielding is provided in the plurality of solenoids, the irregular movement of the plunger due to the magnetic interference between the adjacent solenoids is prevented.
As a result, there is an advantage that the keystroke strength can be accurately reproduced. Further, since the penetrating solenoid is used, there is an advantage that it is possible to prevent a collision noise that may occur during driving with a simple configuration.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view taken along the line A-A ′ of FIG.

FIG. 3 is a sectional view showing how the lock driving device 10 shown in FIG. 1 is attached.

FIG. 4 is a perspective view of the lock driving device 10 shown in FIG. 1.

5 is a diagram showing thrust (a stroke of a plunger) characteristic of the solenoid 11 shown in FIG. 1. FIG.

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

FIG. 7 is a sectional view showing a configuration of a conventional lock driving device.

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

[Explanation of symbols]

3 ... key, 10 ... key driving device, 11A, 11B ...
... Solenoids, 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

Claims (1)

[Claims] 1. A key driving device for an automatic playing piano in which a plurality of solenoids are arranged in a zigzag arrangement on a common yoke. The plurality of solenoids are of a penetrating type, and a magnetically shieldable common yoke is provided on the plurality of solenoids. A key driving device for an automatically playing piano, which is characterized in that