JPH035949Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new and improved rubber cover member for a keyboard device.

In recent years, as a keyboard device for various electronic and electrical devices, a plurality of fixed contact electrodes and required circuit wiring are mounted on a printed circuit board, with or without a spacer member, on the bottom surface thereof. A keyboard device having a structure in which a sheet-like rubber cover member integrally carrying a plurality of movable contacts is placed and integrated in opposition to a fixed contact electrode has come to be widely used.

Adoption of such a rubber cover member greatly simplifies the assembly and integration with the printed circuit board when manufacturing the keyboard device, but as the size of the rubber cover member increases, it becomes difficult to use fixed contact electrodes. A major problem was that alignment with the movable contact became increasingly difficult. The reason why this positioning is difficult is due to molding shrinkage that occurs during molding of the rubber cover member and expansion and contraction during use. In the case of a rubber cover member with a side length of up to 20 cm, molding shrinkage occurs by several percent relative to the mold dimensions, and as a result, the rubber cover material shrinks by several percent relative to the mold dimensions. The movable contact of the member becomes misaligned with the expansion and contraction of the rubber cover member during use, and as a result, it comes to face the adjacent fixed contact, causing malfunction.

For this reason, conventionally, when molding this rubber cover member, it has been designed to be slightly larger in anticipation of molding shrinkage and expansion and contraction during use, thereby solving the above-mentioned difficulty in positioning. Mold shrinkage and expansion and contraction during use vary depending on the size and shape of the rubber cover member for the keyboard device, as well as the rubber material used. In extreme cases, the mold shrinkage rate may vary even with the same material but with different lot numbers. However, due to the different expansion and contraction ratios during use, accurate alignment was still difficult.

In view of the above, the present invention provides a new and improved rubber cover member for a keyboard device whose positioning is easy. Each of the rubber cover members 2 has at least one small positioning hole 4 in the base portion thereof.
The rubber cover member for a keyboard device according to the present invention is characterized in that it is provided with a thin partitioning band 3 which is divided into at least two areas, each of which includes a keyboard and a plurality of push button control units 1. When assembling the device, the purpose is to adjust the dimensional error of the rubber cover member for the keyboard device with respect to the printed circuit board using the thin section band.

Hereinafter, the present invention will be described in detail based on the accompanying drawings.

FIG. 1 shows a typical embodiment of the rubber cover member for a keyboard device according to the present invention, which consists of a rubber cover member 2 provided with a plurality of square dome-shaped push button control parts 1. A movable contact is integrally supported below each push button control section 1. The characteristic feature of the rubber cover member for a keyboard device of the present invention is the presence of a thin partition band 3 provided on the base portion of the rubber cover member 2. In this embodiment, the two thin partition bands 3, 3 The rubber cover member 2 is divided into three regions.

The thin section band 3 in the rubber cover member for a keyboard device of the present invention is formed by stretching the rubber cover member 2 mainly at this portion to widen the band width or compressing the rubber cover member 2 to narrow the band width.
This is to correct the dimensional error of the rubber cover member for the keyboard device with respect to the printed circuit board, and to accurately oppose the movable contact to the fixed contact electrode.
This can also be effectively used in cases where the dimensional error cannot be absorbed by simply widening the width of the thin section band, and when the band is cut into each area and then aligned.

Therefore, the thickness of the thin section band is approximately 0.1 to 0.5 mm, whereas the thickness of the rubber cover member is usually around 1 mm, and the band width is 1 mm.
It is desirable to set it to about 5 mm.

Further, regarding this thin partition band 3, an example is shown in FIG. 1 in which a simple U-shaped or V-shaped groove is formed on the surface of the base portion of the rubber cover member 2. The rubber cover member may have a cross-sectional shape as shown in FIGS. 3 and 3, which makes it easier to stretch or contract the rubber cover member when aligning it with the printed circuit board. moreover,
FIG. 1 shows an example in which two thin dividing bands 3 are provided so as to divide the rubber cover member 2 into approximately three equal parts. , which can be provided in various patterns as required.

To assemble and integrate a keyboard device using the rubber cover member for a keyboard device according to the present invention,
As with conventional keyboard devices of this kind, a rubber cover member for the keyboard device is arranged on a printed circuit board via a spacer member if necessary, and the guide pins provided on the printed circuit board are connected to the rubber cover member 2.
between the printed circuit board and the rubber cover member 2 by inserting a mounting screw into a small hole 4 provided in the printed circuit board and the rubber cover member 2, or by inserting a mounting screw into a small hole provided in both the printed circuit board and the rubber cover member 2. After alignment, they may be joined and integrated using a suitable adhesive or adhesive, or they may be tightened and integrated using the above-mentioned mounting screws.

During the above alignment, even if the dimensions of the rubber cover member for the keyboard device are smaller or larger than the predetermined dimensions of the printed circuit board, stress acts on the rubber cover member, and this stress causes the above-mentioned guide pins or mounting screws to act on the rubber cover member. If the concentrated stress is concentrated around the small hole 4 for insertion, and the concentrated stress is large, the rubber cover member 2 may be damaged or deformed from the small hole portion, so the small hole 4 is shown in FIG. In this way, thick protrusions 5 are provided around small holes where stress is particularly concentrated, such as small holes located on the periphery of the rubber cover member 2, and if necessary, thick protrusions 5 are provided around all small holes 4. It is desirable to provide section 5. Note that the shape of the thick protrusion 5 may, of course, be cylindrical as shown in the drawings, or may be prismatic, circular, or pyramidal.

As explained above, the rubber cover member for a keyboard device of the present invention has a simple structure in which a thin dividing band is provided on the base portion to divide the member into at least two areas. When assembling and integrating with the printed circuit board, dimensional errors caused by molding shrinkage of the rubber cover member for the keyboard device relative to the printed circuit board and expansion and contraction during use can be easily adjusted by changing the band width of the thin section band mentioned above. In particular, the length of one side is
Even in the case of a rubber cover member for a large keyboard device up to 20 cm, the movable contact on the rubber cover carried by the push button control unit 1 can be accurately opposed to the fixed contact electrode on the printed circuit board. , its practical value is enormous.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a typical embodiment of the rubber cover member for a keyboard device according to the present invention;
FIG. 3 is an enlarged sectional view of different embodiments of the thin section. DESCRIPTION OF SYMBOLS 1...Square push button control part, 2...Rubber cover member, 3...Thin section band, 4...Small hole, 5...Thick wall protrusion.

Claims (1)

[Scope of utility model registration request] A rubber cover member 2 is provided with a plurality of push button control parts 1 integrally carrying movable contacts on its lower surface, and each member 2 is attached to the base part of the rubber cover member 2, each having at least one small positioning hole 4 and a plurality of push button control parts. 1. A rubber cover member for a keyboard device, characterized in that the rubber cover member is provided with a thin dividing band 3 which is divided into at least two regions.