JPS5939756Y2 - electric piano signal generator - Google Patents

Description

[Detailed description of the invention] An electric piano requires a signal generator that converts string vibrations into electrical signals.

Conventionally, this signal generation device includes a method in which electrostatic electrodes are placed opposite the strings and changes in capacitance due to string vibration are used, or a coil is placed opposite the strings and the impedance changes are utilized. It was getting worse.

However, the former requires a high-frequency power source, and the latter has a complicated structure.

Moreover, both have the disadvantage that the output is small, the noise is large, and changes in the strength of the sound are eliminated.

The present invention provides a signal generator for an electric piano that does not have the above-mentioned drawbacks.

Fig. 1 is a longitudinal cross-sectional view of a signal generator according to an embodiment of the present invention, and Fig. 2 is a plan view thereof.A piezoelectric element holder 1 in the shape of a metal cylinder with a bottom is provided with a collar 2 at the bottom. At the same time, a through hole 3 for the lead wire is formed, and a screw 4 is provided on the outer surface.

A cylindrical insulator spacer 5, a disk-shaped signal electrode 7 having a lead wire 6, and a columnar piezoelectric element 8 are sequentially inserted into this holder 1 in this order, and a The bottom cylindrical ground electrode 9 is fitted to the lead wire 6.
The holes in the spacer 5 and the holes 3 in the holder are drawn out to the outside.

The enlarged opening of the ground electrode 9 is inserted into the interior of the cylindrical holder 1 and brought into contact with the inner surface thereof.

FIG. 3 is a longitudinal sectional view showing an example of an electric piano equipped with the above-mentioned signal generator, and FIG. 4 is a partially enlarged view.

That is, a keyboard 11 is provided at the front of the housing 10, and hammers 12 are interlocked with the base ends of each weight.

Further, a metal base plate 13 is provided on the back surface of the casing 10, and strings 16 of each scale are stretched around pins 14, 15, etc. implanted in this base plate.

A hammer 12 linked to each weight faces each of the strings 16, and when a key is struck, the hammer 12 rotates in the direction of arrow a and applies an impact to the string 16, so that the string has a predetermined frequency. Vibrate.

Further, a recess 17 is provided in the base plate 13, and the signal generator 18 is screwed into the bottom of the recess 17. It is a structure that has been strung up.

In the electric piano described above, when the strings 16 vibrate, the vibrations are applied to the piezoelectric element 8 via the bridge 19.

Therefore, an alternating voltage corresponding to the vibration is generated between the ground electrode 9 and the signal electrode 7 which are in contact with both ends of the piezoelectric element 8.

Moreover, since the electrode 9 is connected to the base plate 13 via the holder 1, a signal voltage is sent from the lead wire 6 of the electrode 7 by grounding the base plate.

That is, as shown in FIG. 4, by amplifying this signal with an amplifier 20 and applying it to a speaker 21, a sound of a scale corresponding to each weight of the keyboard 11 can be obtained.

As described above, in the electric piano signal generating device according to the present invention, the crown-shaped ground electrode is exposed at the tip of the holder and is in direct pressure contact with the bridge. It can be received directly and converted into an electrical signal, so high-order overtones are not absorbed by the base board and can be picked up directly.A sufficiently large output is obtained, there is little noise, and it is easy to adjust the force with which the keys are struck. Correspondingly, the sound quality with changes in strength is faithfully conveyed.

Further, in the signal generating device for an electric piano according to the present invention, the base plate and the holder screwed into the through hole of the base plate are made of metal, and a ground electrode is in contact with the tip of the holder. Since the holder and the base plate also serve as lead wires for the ground electrode, it is only necessary to provide lead wires for the signal electrodes with respect to the holder.

Therefore, the signal generating device for an electric piano according to the present invention is easy to manufacture, and the electric piano to which such a device is attached becomes extremely easy to wire the lead wires.

Furthermore, since the electric piano signal generating device according to the present invention is provided with a collar at the base of the holder, if the holder is rotated by grasping the outer circumferential surface of the holder, the screws of the holder can be removed. The rotational moment is larger on the outer peripheral surface of the collar than on the groove surface, so the holder can be rotated extremely easily without any processing on the base plate. Screwing into the through hole and adjusting the contact pressure of the ground electrode to the piece can be easily performed.

As described above, the practical value of the present invention is extremely limited.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a signal generator according to an embodiment of the present invention, FIG. 2 is a plan view of the signal generator of FIG. 1, and FIG.
FIG. 4 is a longitudinal cross-sectional view showing an example of an electric piano equipped with the signal generator shown in FIG. 4, and FIG. 4 is an enlarged view of a part of FIG. In the figure, 1 is a holder for the piezoelectric element, 2 is a collar, and 3 is a holder for a piezoelectric element.
1 is a hole, 4 is a screw, 5 is a spacer, 6 is a lead wire, 7 is a signal electrode, 8 is a piezoelectric element, 9 is a ground electrode, 10 is a housing, 1
1 is a keyboard, 12 is a hammer 13 is a base plate, 14. 15
is the pin, 16 is the string, 17 is the four parts, 18 is the signal generator, 1
9 is a piece, 20 is an amplifier, and 21 is a speaker.

Claims (1)

[Scope of utility model registration request] The bridge is equipped with a string-strung bridge, a base plate disposed adjacent to the bridge, and a signal generator. A signal generator is screwed onto the string with its tip pressed against the string, and the signal generator is provided with a screw groove on its outer periphery to be screwed into the through screw hole of the base plate, and has a threaded groove on its tip. is provided with a bottomed cylindrical piezoelectric element holder provided with an opening, and an insulator spacer, a signal electrode, and a piezoelectric element are housed in this order on the bottom of the holder, and the signal electrode In the signal generating device for an electric piano, a lead wire is connected to the substrate and the holder, and the lead wire passes through the insulator spacer, passes through the lead wire through hole of the holder, and is led out. is made of metal, and a piezoelectric element is fitted into the tip of the holder so as to protrude to the outside, and the cap-shaped ground electrode is in contact with the top of the piezoelectric element, and covers the top of the piezoelectric element; , the ground electrode is inserted into the holder and brought into contact with the holder; further, the ground electrode is pressed against the piece, and a hub is installed on the outer periphery of the holder. Electric piano signal generator.