JPS6028023Y2 - Keyboard device for electronic musical instruments - Google Patents

Description

[Detailed description of the invention] This invention is based on a printed circuit board on which a plurality of fixed contacts are formed corresponding to the arrangement spacing of a plurality of keys, and a movable integrated structure connected to the plurality of fixed contacts. The present invention relates to a keyboard device for an electronic musical instrument in which a key switch configured by arranging contacts is attached to a keyboard frame.

In conventional keyboard devices for electronic musical instruments, key switches made of metal contacts such as leaf contacts were provided separately and independently for each line, so the structure of the key switch and its installation was complex and the number of parts was large. In many cases, many man-hours are required for assembly, which not only makes the keyboard device complicated, large, and expensive, but also has drawbacks such as the tendency for the switch contacts to chatter when they are in contact.

This idea was made in view of the above points, and by applying recent digital technology, it is possible to determine which key was pressed by time-division scanning of the key press operation of each line using a movable contact of a connected and integrated structure. As the applicant has developed an electronic musical instrument that detects and generates a musical tone corresponding to the pressed key using a musical tone composition circuit, the electronic musical instrument is printed in accordance with the arrangement spacing of the movable contacts and each line. A key switch having a simple structure, which is formed on a board and includes a fixed contact that is turned on and off by the movable contact, is easily and reliably attached to the keyboard frame together with the printed board, and prevents warping or deformation of the printed board. It is designed to be preventable.

Hereinafter, embodiments of this invention will be described with reference to the accompanying drawings.

FIG. 1 partially shows a key switch used in a keyboard device according to this invention.

In the figure, reference numeral 1 denotes a printed circuit board, and fixed contacts 2 are formed on the upper surface of the printed circuit board 1 along its longitudinal direction in correspondence with the arrangement intervals of the respective lines.

Each fixed contact 2 consists of a pair of electrodes 2at2b formed in a printed pattern close to each other, one electrode 2at2b.
a are commonly connected for each octave, and the other electrode 2b
are commonly connected to each note via a diode 3.

A movable contact 4 is placed on the printed circuit board 1 over the entire width in the direction in which the keys are arranged.

This movable contact 4 has a hollow structure movable part 4 on which electrodes 5 made of conductive rubber are divided into octaves and pasted on the bottom surface.
a, and thick fixed parts 4b and 4c disposed on both sides parallel to the movable part, and each of these parts is connected to the movable part 4a.
The electrodes 5 affixed to the printed circuit board 1 are connected to each other via thick support pieces 4d and 4e, respectively, so as to be arranged at a slight distance from the fixed contacts 2 formed on the printed circuit board 1.

The portion of the movable contact 4 other than the electrode 5 is made of an insulating elastic material such as silicone rubber.

Alternatively, the entire movable contact 4 may be made of conductive rubber, and an insulating spacer may be interposed between the fixed parts 4b, 4c and the printed circuit board 1.

FIG. 2 shows a keyboard device for an electronic musical instrument, which is an embodiment of the present invention and incorporates the key switch 7 constructed on the printed circuit board 1 in this manner.

In the same figure, reference numeral 11 is a key, the rear end of which protrudes somewhat from a window 12a provided at the rear rising portion of the keyboard frame 12, and a fulcrum groove 11a provided on the top surface of the key 11 extends from the window 12a.
It fits on the upper edge of the.

Then, the spring ring holding hole 11b and the keyboard frame 12
The arm portion 1 is rotated upwardly by a compression spring 14 interposed between the spring holder 13 provided in the arm portion 1
1c comes into contact with the lower surface of the upper limit stopper 15 to restrict its upward movement position and is maintained in a substantially horizontal state.

11d is an actuator fixed to the lower surface of the key 11 for operating the key switch.

Further, reference numeral 16 denotes a key guide that restricts the swinging of the key 11 in the left and right direction when the key is pressed.
The area around b is made of synthetic resin or the like.

A printed circuit board 1 constituting the key switch 7 explained with reference to FIG. Fixing parts 4b and 4c (first
It is placed with the side of the figure (see figure) pressed against it.

Note that details of these structures will be described later.

Then, when the key 11 is pushed down in the direction of arrow A by pressing the key, the actuator lid descends, passes through the through hole 12c formed in the key frame 12, and presses and deforms the movable part 4a of the fixed contact 4. , the electrodes 2a and 2b of the fixed contact 2 formed on the printed circuit board 1 are short-circuited by an electrode 5 made of conductive rubber stuck to the lower surface thereof.

Therefore, the fixed contact 2 corresponding to the key depression is closed (see FIG. 1).

Then, which key is pressed is detected by time-division scanning using a circuit (not shown).

Next, the structure of the substrate holder 17 will be explained in detail with reference to FIGS. 3 to 5.

Figure 3 is an enlarged sectional view of the main part of Figure 2, and Figure 4 is the arrow B.
FIG. 5 is a plan view of only the substrate holder 17 viewed from the -B direction, and a cross-sectional view taken along the line D-D.

FIG. 3 corresponds to a sectional view taken along line CC in FIG. 4.

The substrate holder 17 has a first holding part 21 and a second holding part 22.
, a connecting portion 23 that connects the two, a movable contact holding portion 24, and an auxiliary connecting portion 25 that connects it to the second holding portion 22, and are integrally formed of, for example, synthetic resin.

The first holding portion 21 has a continuous side surface 21a having a length substantially equal to the length in the longitudinal direction of the printed circuit board 1.
A groove 21b having a width approximately equal to the thickness of the printed circuit board 1 is provided along the longitudinal direction of the printed circuit board 1.

The second holding part 22 has a planar movable contact holding surface 22 on the inside.
a, and is formed into a protruding body, for example, a columnar body, which is inserted into a through hole 1a formed in the printed circuit board 1.

On the outside, a thin arc-shaped pawl is integrally formed with a protrusion 22b that holds the printed circuit board 1 from above and a pawl 22c that holds the printed circuit board 1 from below and engages an engagement hole 1b formed in the printed circuit board 1. It includes a holding part 22d.

A plurality of second holding parts 22 are provided along the longitudinal direction of the first holding part 21 at appropriate intervals.

Reference numeral 26 denotes a screw hole provided in the first and second holding parts, and a small protrusion 27 for screw locking protrudes from the inner circumferential surface of the hole, and the mounting screw 18 is self-retained when attached to the keyboard frame 12. to make your work easier.

The printed circuit board 1 is mounted on the circuit board holder 17 configured in this way.
To mount the printed circuit board 1, the second board holder 22 is inserted into the through hole 1a of the printed circuit board 1 from above in FIG. 3, and the movable contact holding protrusion 24 is inserted into the through hole (not shown). It is only necessary to push it in the direction of arrow E so that the side edge portion 1e fits into the groove 21b of the first holding portion 21.

In this way, the side edge 1e in the longitudinal direction of the printed circuit board 1, that is, in the longitudinal direction of the keyboard, is aligned with the R of the first board holder 21.
21b, and a claw 22c is inserted into the engagement hole 1b.
engages to prevent horizontal movement of the printed circuit board 1,
The intermediate portion of the printed circuit board 1 is held between the protrusion 22b of the second holding portion 22 and the claw holding portion 22d.

The inner surface 21a of the first holding part 21 and the second holding part 22
The distance between the movable contact holding surface 22a and the inner surface of the movable contact holding protrusion 24 is a dimension that regulates the position of the movable contact 4 in the width direction.
If it is placed on the printed circuit board 1 so that the side surface of 4c is held in pressure contact, its position is correctly regulated.

The key switch assembled in this manner so as to be able to operate as a switch may be fixed to the keyboard frame 12 with the mounting screws 18.

Then, the fixed parts 4b and 4c of the movable contact 4 are held between the printed circuit board 1 and the keyboard frame 12 at the top and bottom, and the side surfaces are held by the eleventh and second holding parts, so that the movable contact 4 can be positioned and held more reliably.

In addition, although the movable contact holding part 24 is provided in the above embodiment, the movable contact holding part 24 is not necessarily necessary if a relatively large number of second holding parts 22 are provided.

Furthermore, if a board holder like the one in the above embodiment is used, mounting of the printed circuit board is easy and reliable, and it is convenient because the board holder can be assembled together before attaching the key switch to the keyboard frame. However, it is not always necessary to use such a substrate holder.

For example, various types can be used, such as one in which the first and second holding parts are separate parts, and one in which the second holding part simply holds the printed circuit board by sandwiching it from both sides.

As described in detail above, according to this invention, the structure of the key switch is extremely simple, the number of parts can be reduced, and the assembly process can be simplified. Since the side surface of the thick fixed part is held under pressure, the movable contact can be held accurately and reliably, and the same operation can be performed for each wire.

Furthermore, if conductive rubber is used for the movable contact, it will have good adhesion to the fixed contact, and chattering can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a perspective view partially showing a key switch used in a keyboard device according to this invention, and FIG. 2 is a side sectional view in the longitudinal direction of a key of a keyboard device for an electronic musical instrument showing an embodiment of this invention. 3 is an enlarged sectional view of the main part of FIG. 2, FIG. 4 is a plan view of only the substrate holder seen from the direction of arrow BB in FIG. 3, and FIG.
The figure is a sectional view taken along the line DD in FIG. 4. 1... Printed circuit board, 2... Fixed contact, 4... Movable contact, 4a... Movable part,
4b, 4c... Fixed part, 7... Key switch, 11... Key, 12... Keyboard frame, 17... Board holder Ingredients, 21...
1st holding part, 22...2nd holding part.

Claims (1)

[Claims for Utility Model Registration] 1. A keyboard frame on which a plurality of keys are mounted, and a keyboard frame fixed to the frame via a board holder in parallel with the frame, and a plurality of fixed contacts are formed corresponding to each line. A printed circuit board is arranged on the printed circuit board, and has a common connection integral structure for the plurality of fixed contacts, and has a central movable part and a thick wall mounted on both sides thereof via thin supporting pieces. and a key switch constituted by a movable contact having a fixed part, and the board holder has first and second holding parts, and at least the first holding part allows the printed circuit board to be held. By holding the side edges in the longitudinal direction of the keyboard, the printed circuit board is prevented from warping, deforming, etc., and the movable contacts arranged on the board are fixed by the first holding part and the second holding part. A keyboard device for an electronic musical instrument in which the side surfaces of the parts are held in pressure contact. 2. The second holding part of the board holder is a protrusion that is fitted into a through hole drilled in a printed circuit board to hold the printed board; A keyboard device for an electronic musical instrument according to claim 1, which is integrally connected with a holding portion.