JPS594526Y2 - Piano keyboard movement detection device - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a keyboard movement detection device for a piano for automatic performance.

With the recent development of comprehensive electronics technology, automatic performance devices record piano performances on cassette tapes and replay them as live performances on an unspecified number of pianos.
Also known as piano performance sound, it has been put into practical use.

First, when recording the piano performance sound, the types of information output from the cover board include the time the keys are struck, the timing before and after that, the strength of the keystrokes, and the amount of pedal depression. are detected as electrical signals, A/D converted, and recorded on a cassette tape of a tape recorder. To play this, a solenoid for pressing a key and a solenoid for pressing a pedal are activated. Number of Output Signals: Drive signals for solenoid to press keys by playing back the recorded cassette on a tape recorder, or the length and shortness of time as a pedal depression signal, and the timing can be used as is for other pianos. Or it can automatically repeat the performance on the piano itself.

However, simply installing a mechanical switch as a key sensor is not sufficient to faithfully capture the delicate key touches of a live piano performance or the performance technique in which even slight time differences cannot be ignored.

In other words, in the case of a mechanical switch, the ON/OFF of the contact
Occasionally, a characteristic chattering occurs, and it is necessary to devise a protection circuit to electrically prevent this, or to take measures to receive signals when handling small signals, or because the touch pressure on the key changes due to a mechanical switch, it may cause the recorded data to change. This caused unexpected problems such as noise interference and timing disturbances.

Therefore, in order to eliminate the above-mentioned drawbacks, this proposal adopts a non-contact optical switch that does not feel touch pressure to detect the key press operation, and measures the distance from when the switch first moves until it operates, that is, the operating point. It is an object of the present invention to provide a piano keyboard operation detection switch in which the above-mentioned non-contact optical switches are arranged side by side on a key switch bracket rail so that each switch can be easily adjusted.

The present invention will be described below with reference to the illustrated embodiments.

In FIG. 1, a keyboard 1 is mounted so as to be movable using a balance rail 2 as a fulcrum, and its tip lightly contacts a key rail 3 stretched in the horizontal and longitudinal direction.

On the other hand, the rear end of the keys, that is, the player's side, like the key rail 3, is mounted horizontally on a horizontally installed front rail 4 with an interval corresponding to the key stroke.

The balance rail 2, key rail 3, and front rail 4 are assembled on the bed 5 of the piano body as shown in the figure.

The photointerrupter switch 6 is located below the keyboard 1 configured as described above and is fixed on the key switch bracket rail 7. For example, the photointerrupter switch 6 converts light output from a light emitting diode into an electrical signal using a photo sensor and outputs it. The switch operation for cutting off the light emission is performed by moving the shield 8 provided below the keyboard 1 up and down as the keys are pressed.

Furthermore, the key switch bracket rail 7 mounts the photointerrupter switch 6 as described above, and is equipped with an adjustment screw 9 for adjusting the height of the shield 8 given in advance, so that it can be attached to the bed 5. It is combined.

10 is a capstan attached to the tip of the keyboard 1.

FIG. 2 shows the movement of the keyboard 1 when a key is pressed as an ON operation of the photointerrupter switch 6 and the shield 8.

In addition, although the figure describes the case where the photo interrupter switch 6 is installed between the balance rail 2 and the key rail 3, other installation positions are possible.
It may be provided between the balance rail 2 and the front rail 4.

At that time, the action of the shield 8 is such that light is blocked at the normal keyboard mounting position, and a slit may be provided at a predetermined position in the shield so that light can be transmitted through keystroke operations.

Therefore, according to the present invention, compared to the conventional mechanism for outputting keystroke signals using mechanical switches, a non-contact photo-interrupter system is adopted, so there is no contact nozzle, which is most disliked by piano coders, and chattering when turning ON or OFF. Since there are no such problems, and the feel of the key touch is no different from that of a normal piano, there is no rhythm disturbance caused by this, and it is extremely effective as a key sensor for recording automatic performance pianos.

In addition, since it is small and simple, it can be said to be ideal for this type of application where there are restrictions on installation location.

Furthermore, since the contactless optical switch is configured to be able to adjust the distance from the shield provided on the underside of the keyboard, the distance from when a key is pressed until the contactless optical switch operates, that is, the operating point, can be adjusted. It is easy to perform, and has the effect of faithfully detecting and recording as an electrical signal the performance techniques that cannot be ignored, such as subtle key touches and slight time differences in live piano performance.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram showing the structure of the piano flange board motion detecting device of the present invention, and FIG. 2 is a diagram of the operation when a key is pressed in FIG. 1. 1...Keyboard, 2...Balance rail,
3...Key rail, 4...Front rail, 5...Bed, 6...Photo ink button switch, 7...Key switch Bracket rail, 8...Shield, 9...
...adjustment screw, 10...capstan.

Claims (1)

[Scope of Claim for Utility Model Registration] A piano keyboard mounted swingably on a balance rail installed horizontally on the bed of the piano body, and placed on the bed so that one end of the flange board comes into contact with the piano keyboard. A horizontally installed key rail, a front rail that is installed horizontally on the bed so that the other end of the keyboard comes into contact with it, and a key switch bracket rail that is arranged in series between the keyboard and the bed. A non-contact optical switch is provided on the bottom surface of the keyboard, and the non-contact optical switch is turned on by the rocking motion of the keyboard. A piano comprising: a shield provided for OFF control; a screw for attaching the key switch bracket rail for adjusting the distance between the non-contact optical switch and the shield so as to adjust the height position relative to the bed; keyboard movement detection device.