JPH0683331A - Key drive unit fitting structure of automatic piano - Google Patents

Abstract

PURPOSE:To provide the key drive unit fitting structure of the automatic piano which is made high in the performance of the actuator of an upright automatic piano. CONSTITUTION:The rear end of the shelf plate 8 of the piano is made short and a key drive unit 1 is arranged behind the shelf plate 8; and both the end parts of the key drive unit 1 are supported by the master plate of a piano body respectively and the center part of the key drive unit 1 is supported by the frame 14 of the piano body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic piano, and more particularly to a key drive unit mounting structure for mounting a key drive unit for driving a key on a piano body.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Publication No. 3-55834 has been proposed as a key drive unit mounting structure. That is, the common yoke, which is formed in a substantially U shape and extends in common for a plurality of keys, is arranged on the upper surface of the rear end portion of the shelf plate via the placket. The common yoke is
It is arranged at an inclination angle that is almost the same as the inclination angle of the key, and a plurality of electromagnetic plungers corresponding to each key are arranged in a zigzag pattern, so that it is divided into a front row electromagnetic plunger and a rear row electromagnetic plunger. ing.

In this case, since the common yoke is inclined so as to face the lower surface of the key in parallel, the distances between the push-up buttons of all the electromagnetic plungers and the lower surface of the key are set to be equal. Further, the stroke of the push-up button of the front row electromagnetic plunger is set to be smaller than the stroke of the push-up button of the rear row electromagnetic plunger by about 1 to 2 mm, whereby the depth at which the front end of the key is depressed is set to be equal.
Further, the stroke of the key is finely adjusted and the impact is absorbed by the back rail.

According to this structure, the back rail is arranged on the upper surface of the rear end of the shelf plate via the common yoke and the placket. That is, the key drive unit is incorporated between the back rail and the balance pin.

[0005]

By the way, according to the above-mentioned conventional technique, the space is limited (particularly the height) and the performance of the actuator cannot be improved. That is,
There is a problem in that the coil length of the key driving solenoid cannot be increased and it is difficult to flatten the thrust characteristic (plunger stroke-to-thrust characteristic). Further, since the lever ratio causes an unreasonable force to be applied to the keyboard, the keyboard is easily lifted up, and the keyboard pressing force by the keyboard pressing is required. Therefore, there is a drawback that the playback performance of the automatic playing piano is poor. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a key drive unit mounting structure for an automatic piano in which the performance of an actuator is improved in a vertical automatic piano.

[0006]

In order to solve the above-mentioned problems, according to the present invention, a key drive unit mounting structure for mounting a key drive unit formed by connecting a plurality of key driving solenoids to a piano body is provided. The rear end of the shelf plate is shortened, the key drive unit is arranged behind the shelf plate, and both ends of the key drive unit are supported by the master plate of the piano body.

[0007]

With the above structure, the key drive unit supported by both ends of the main plate of the piano body is arranged behind the shelf plate with the rear end of the shelf plate of the piano shortened. Easy to adjust.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 are views showing a main part of a key drive unit mounting structure according to an embodiment of the present invention. In these figures, reference numeral 1 is a key drive unit for driving a piano key, and the same number of solenoids 3, 3, ... As the keys are attached to a long attachment member 2 in a zigzag form in plan view. In this case, a plunger pin (not shown) is vertically provided at the upper end of the plunger 3a of each solenoid 3, and the key drive head 4 made of resin or the like is attached to the upper end of the plunger pin. Reference numeral 5 is a buffer member that prevents noise when the key driving head 4 returns.

Then, the above-mentioned key drive unit 1
Is behind the piano shelf 8, and as shown in FIG.
It is arranged below the rear end of the key 9. In addition, shelves 8
Has a rear end portion shorter than the conventional shelf board by the width of the key drive unit 1. The minimum value of the predetermined dimension is determined so that the key drive heads 4 of the rear row side solenoids in a staggered arrangement can contact the lower surface of the rear end of the key. Next, in FIG. 1, reference numeral 11 is a right side parent plate of the piano, an L-shaped angle 12 is attached to the left side surface of the parent plate 11, and the right end portion of the key drive unit 1 is attached to the horizontal portion of the angle 12. Is attached. Similarly, although not shown, an angle is attached to the left main plate, and the left end of the key drive unit 1 is attached to this angle.

Next, in FIG. 2, reference numeral 14 is a piano frame. An extension fitting 15 formed by bending a steel plate is attached to a protrusion (a nose of a tengu) 14a provided at two positions in the width direction of the frame 14 with a bolt 16, and a spacer 17 is attached to a tip of the extension fitting 15 via a spacer 17. The rear end of the shelf plate 8 is attached by screwing. Further, the bolt 2a that can be tightened from the upper surface of the mounting member 2 of the key drive unit 1 and projects to the lower surface thereof comes into contact with the protrusion 14a, so that the key drive unit 1
Is supported. That is, the bolt 2a that engages with the protrusion 14a has a function of preventing the key drive unit 1 from bending and also serves as an adjuster for height adjustment. Therefore, it is possible to adjust the heights of the two central portions of the key drive unit 1 in accordance with the warp caused by the individual variation of crying.

A back rail 20 is attached to the upper surface of the rear portion of the shelf plate 8 and includes a mounting bracket 20a having a Z-shaped cross section and a felt (shock absorber) 20b mounted on the upper surface of the mounting bracket 20a. There is. The back rail 20 receives the rear end of the key 9, and is attached to the front side of the conventional piano somewhat. In addition, in the conventional piano, the upper surface of the felt 20b is parallel to the upper surface of the shelf board 8. In this embodiment, however, the upper surface of the felt 20b is parallel to the lower surface of the key 9 due to the bending angle of the mounting bracket 20a. It prevents the disturbance of pacing according to the inclination of.

Next, the effect of the above embodiment will be described. (1) Attach the back rail 20 to the mounting bracket 20a and the bolt 2
Since it is configured with b, it has good dimensional stability and little change over time. (2) Since the upper surface of the back rail 20 is parallel to the lower surface of the key 9, the sound of the keyboard falling can be reduced more than ever, and the pacing can be stabilized. (3) Further, the mounting height of the key drive unit 1 can be adjusted by the tightening condition of the bolt 2a. (4) Since the back rail 20 and the shelf plate 8 are not directly connected, there is an effect that mechanical noise of the key drive unit 1, particularly falling sound of the plunger 3a is hard to be heard. (5) With the configuration described above, a keyboard rear end push-up method for improving playback performance can be realized, and a penetrating solenoid with no collision noise can be used as the plunger. That is, the absolute thrust force and thrust-stroke characteristics of the solenoid can be improved, and the degree of freedom in designing the solenoid and the performance thereof can be increased.

In this embodiment, the frame 14
Although the extension fitting 15 is used to fix the shelf plate 8 to the shelf plate 8, the frame 14 may be extended. According to this, without using the extension fitting 15, the frame 1
4 and the shelf plate 8 can be fixed to each other. Further, the key driving head 4 of the key drive unit 1 may be configured to receive the lower surface of the rear end of the key. In this case, the back rail 20 is unnecessary.

[0014]

As described above, according to the present invention, the rear end of the shelf of the piano is shortened, the key drive unit is arranged behind the shelf, and both ends of the key drive unit are respectively connected to the piano. Since the mounting structure is supported by the main plate of the main body, the performance of the actuator can be improved.

[Brief description of drawings]

FIG. 1 is a front view showing the configuration of an embodiment of the present invention.

FIG. 2 is a side view showing the configuration of an embodiment of the present invention.

[Simple explanation of symbols]

1 ... Key drive unit, 2 ... Mounting member, 3 ...
Solenoid, 3a ... Plunger, 4 ... Key drive head, 5 ... Buffer member, 8 ... Shelf plate, 9 ... Key, 11 ...
... Parent board, 12 ... angle, 14 ... frame, 14a
...... Protrusion, 15 ...... Extension metal fitting, 2a ...... Bolt, 17 ...
... Spacer, 20 ... Back rail, 20a ... Mounting metal, 20b ... Felt.

Claims (1)

[Claims] 1. A key drive unit mounting structure for mounting a key drive unit formed by connecting a plurality of key driving solenoids to a piano body, wherein a rear end of a shelf plate of the piano is shortened and the key drive unit is arranged behind the shelf plate. A key drive unit mounting structure for an automatic piano, characterized in that both end portions of the key drive unit are supported by a main plate of the piano body.