JPS6027430Y2 - electric piano frame structure - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a frame structure for an electric piano that allows easy positioning and attachment of mechanical and electrical transducers.

In an electric piano, the vibrations of the strings when the strings are struck are converted into electrical signals, which are then output as they are or after being amplified with a slight change in tone and then emitted from the speaker. A piezoelectric element is used as an example of a conversion element.

FIG. 1 is a block diagram showing the structure of a conventional mounting structure for this type of piezoelectric element.

To explain this with reference to the figure, the string 1 has both ends locked to tuning pins 3 and frame pins 4, which are implanted on the top surface of a frame 2 integrally formed in a frame shape of cast iron, etc., and the middle part Each string 1 is supported under pressure by a string support member 5 provided corresponding to each string 1, thereby being stretched with a predetermined tension.

The string support member 5 is fixed on a fixing member 12 disposed in a recess 7 of a pedestal 8 fixed to the upper surface of the frame 2, and a mechanical and electrical connection is provided between the fixing member 12 and the pedestal 8. A conversion element 6 is interposed.

The electromechanical transducer 6 includes a pair of electrodes 10a and 10b, and a piezoelectric element 9 disposed between these electrodes 10a and 10b.
and an insulator 11 disposed between the electrode 10b and the pedestal 8.

However, in such a structure, since the vibration of the string 1 is transmitted to the frame 2 via the pedestal 8, there is a significant loss of vibration of the string, and not only is the sound elongated poorly, but also the pedestal 8 is made of adhesive and set screws. Since it is fixed to frame 2 by
The positioning and installation work is extremely troublesome and has the drawback of poor workability.

Furthermore, because adhesive is used for the pedestal attachment part of the frame 2, gold powder coating cannot be applied, which causes rust and deteriorates the product image.

This idea was made in view of the above points, and by reducing the number of parts, it is possible to reduce sound transmission loss and improve sound quality, and also to precisely arrange each electromechanical transducer at a predetermined interval. The present invention provides a frame structure for an electric piano that can be installed on the frame, and its feature is that a plurality of positioning protrusions are provided on the surface of the frame to form a mounting part for a mechanical-electrical transducer and to restrict its movement. The structure is such that the electromechanical transducer is arranged directly on the frame.

An embodiment of this invention will be described below with reference to the drawings.

FIG. 2 is a perspective view of the main part of the frame structure according to this invention, and FIG. 3 is a plan view of the main part of FIG. 2.

In these figures, mounting portions 20a, 20b are provided at predetermined locations on the upper surface of the frame 2, corresponding to the electromechanical transducers 6, 6 that pick up the vibrations of the strings 1, 1 at each pitch.

Each of these mounting portions 20at20b includes a plurality of positioning protrusions 21a to 21e, 22a to 22 (in this example, five protrusions are provided) integrally protruding from the frame 2.
e (22b to 22d are not shown).

Then, a positioning protrusion 21a constituting the mounting portion 20a
Of the protrusions 21a and 21b, the protrusions 21a and 21b are arranged opposite to each other with an interval that is approximately equal to or slightly larger than the width dimension (the length of the side surface orthogonal to the string 1) of the electromechanical transducer 6, and
c, 21d and 21e are arranged opposite to each other with an interval approximately equal to or slightly larger than the length dimension of the electromechanical transducer element 6 (the length of the side surface parallel to the string 1).

Then, the electromechanical transducer 6 is connected to the positioning protrusion 21.
The lower end portion thereof is inserted into the space surrounded by a to 21e via a punching 23 made of a material such as urethane, so that it is disposed on the upper surface of the frame 2.

In this case, the positioning protrusions 21a to 21e are provided so that only the side surfaces 24a to 24d of the electromechanical transducer 6 are in contact with each other, and each corner 25a to 25d is positioned between adjacent protrusions to escape. The mounting allows the positioning and insertion of the electromechanical transducer 6 to be performed more accurately and easily.

The punching 23 fixes the electromechanical transducer 6 to the frame 2 by pasting double-sided adhesive tape on its upper and lower surfaces, respectively.

Note that the positioning protrusions 22a to 22e of the mounting portion 20b are provided in the same manner as the positioning protrusions 21a to 21e described above, and therefore their description will be omitted.

Thus, according to such a mounting structure for the electromechanical transducer 6, the mounting portion 20a corresponding to each electromechanical transducer 6,
Since 20b is provided integrally with the frame 2, positioning work for the electromechanical transducer 6 can be eliminated.

In addition, since each mounting portion 20a, 20b contacts only each side surface of the electromechanical transducer 6 and leaves the corners free, it is easier to insert and install is more certain.

In other words, when the periphery of the electromechanical transducer 6 is completely surrounded, it is difficult to adhere the hook corner to the mounting part due to precision, so the entire lower surface of the electromechanical transducer 6 is bonded uniformly to the frame. However, if the corners are removed as in the present invention, the entire bottom surface can be brought into close contact with the frame without requiring high precision, which improves the reliability of the mounting surface. be able to.

In addition, since the electromechanical transducer 6 is placed directly on the frame 2 without using a pedestal as a damping material as in the past, the transmission loss of sound to the frame 2 is reduced, resulting in a high volume and crisp sound. It provides a jazz-like sound quality and is suitable as a component type electric piano.

Furthermore, since no adhesive is used when attaching the electromechanical transducer 6, the entire frame 2 can be coated with gold powder, eliminating the occurrence of rust.

``Although the above embodiment describes the case where the string 1 is directly supported by the electromechanical transducer 6, the present invention is not limited to this.For example, the string support member may be made of synthetic resin, and the electromechanical transducer 6 may be molded therein. You may.

Further, if the frame 2 integrally equipped with the mounting parts 20a and 20b is formed by casting using a casting method disclosed in Japanese Patent Publication No. 50-840 and already in practical use, the mounting parts 20a and 20b can be formed by casting. uniformly and with high precision,
In addition, the casting surface is smooth, requiring almost no surface processing after casting, and the casting can be formed in one piece.

As described above, according to the frame structure of the electric piano according to the present invention, a mounting portion integrally protrudes from a predetermined location on the upper surface of the frame and discontinuously surrounds the peripheral side surface of each mechano-electrical transducer to allow the corners to escape. Therefore, it is possible to easily and accurately arrange the elements at predetermined intervals without the need for positioning work, and as a result, the reliability of the element mounting surface can be further improved.

In addition, since the elements are placed directly on the frame, the number of parts can be reduced, and the practical effects are very large, such as reducing sound transmission loss to the frame and improving sound quality and volume. It is.

[Brief Description of the Drawings] Fig. 1 is a sectional view showing an example of the mounting structure of a piezoelectric element in a conventional electric piano, and Fig. 2 is a perspective view of essential parts showing an example of the frame structure of the electric piano according to this invention. FIG. 3 is a plan view of the main part of FIG. 2. 1...Strings, 2...Frame, 6...
... Mechanical and electrical variable detection elements, 21a to 21e. 22a to 22e...Positioning protrusions.

Claims (1)

[Scope of utility model registration request] In an electric piano in which string vibration is detected by a mechano-electric conversion element arranged on a frame and converted into an electric signal, a plurality of electric pianos in which only each side surface of the mechano-electric conversion element is in contact with the upper surface of the frame and corners are escaped. A frame structure for an electric piano characterized by integrally protruding positioning protrusions.