JPH04329228A - Push button switch with drip-proof structure - Google Patents

Abstract

PURPOSE:To provide a push button with a drip-proof structure capable of completely stopping permeation of humidity and water entering from the keytop side, requiring only a small number of parts to suit a reduction in size and in thickness, and free from limitation in terms of its mounting position and thus able to be mounted even to a curved surface portion, such as a corner portion, of an appliance casing. CONSTITUTION:A loop-like drip-proof frame 17 is formed using a flexible resin material by a resin mold watertightly with respect to a resin film 16 in such a manner as to enclose a specified range of the resin film 16. Key-tops 18 are resin molded within the frame 17 and are made watertight with respect to the resin film 16, thus being made to serve as switch operating members. Resin sheets 13, 14 formed with a stationary contact 12a and a movable contact 14a are disposed on a base body 11 whose surface is curved. The frame 17 and the base-body 11 surface are disposed in a watertight condition.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a push-button switch having a so-called drip-proof structure that prevents external moisture and moisture from entering contact portions.

0002

2. Description of the Related Art In recent years, with the miniaturization of electronic devices, there has been a demand for push button switches used in the operating sections of such devices to be smaller and thinner. Many of these electronic devices are used in a variety of environments, and there is a particular demand for push button switches with a so-called drip-proof structure, which prevents moisture and moisture from entering the contact portions from the outside.

[0003] In order to meet these demands, FIG.
There was a structure shown in . In FIG. 11, 61,6
Reference numeral 2 denotes a sheet on which a contact pattern is formed, and the sheets 61 and 62 are arranged on the bottom surface of the switch frame 69 vertically facing each other with a spacer 63 interposed therebetween, and are integrated with a panel 65 arranged on the upper part of the sheet 61. By pressing the formed hinge-type key top 64, a contact pattern (movable contact) is formed on the sheet 61 via the click spring 68.
The push button switch is configured such that the contact pattern (fixed contacts) formed on the sheet 62 can be brought into contact with the contact pattern (fixed contacts).

[0004] In the push button switch having the above structure, the external
A drip-proof sheet 6 is provided between the sheet 61 and the key top 64 to prevent moisture and moisture from entering the cabinet 65 mainly from the key top side from penetrating into the switch contacts.
6, the drip-proof sheet 66 and the cabinet 65
A rubber packing 67 is interposed between them to provide a drip-proof structure. FIG. 12 is a plan view showing the shapes of the rubber packing 67 and the drip-proof sheet 66.

[0005]

[Problems to be Solved by the Invention] The push button switch having the above structure prevents moisture and moisture from entering the contact portion from the outside.
Although it has a so-called drip-proof structure, it is not suitable for thinning because it has a large number of parts and requires a predetermined operating stroke of the key top, and furthermore, the key top does not have a hinge mechanism with a predetermined length. Because of this, they are not suitable for miniaturization, and are also not perfect in terms of so-called drip-proofing, which blocks moisture and moisture from entering from the outside from penetrating into the contact areas.

[0006] Furthermore, as recent electronic devices are pursued to be miniaturized to the utmost, it is not possible to freely select the mounting position of the push button switch for operating the device. It may be necessary to install the However, in the conventional push button switch described above, since the switch frame 69 has a planar shape, there is a restriction that the switch frame 69 must be mounted on a flat part.

The present invention has been made in view of the above-mentioned points, and can completely block the penetration of moisture and water from the key top side, has a small number of parts, is suitable for miniaturization, and is suitable for downsizing and thinning. It is an object of the present invention to provide a push button switch having a drip-proof structure that can be mounted on a curved surface such as a corner of a device housing without being restricted by the mounting position.

[0008]

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a fixed contact and a movable contact formed on a resin sheet surface and arranged facing each other, and a fixed contact and a movable contact arranged above the movable contact. A push-button switch equipped with a key top to be pressed, in which a loop-shaped drip-proof frame is molded with a flexible resin material into a resin film so as to surround a predetermined area of the resin film in a watertight state with the resin film. At the same time, a key top is resin-molded in a loop-shaped drip-proof frame and formed in a watertight state with the resin film to form a switch operating body.A resin sheet with fixed contacts and movable contacts is molded with a curved surface. The drip-proof frame surrounds at least the portion of the resin sheet where the fixed contacts and movable contacts are formed, and the switch operating body is placed on the base surface so that the key top is located above the movable contacts. It is characterized by the droplet frame and the base surface being arranged in a watertight state.

[0009]

[Function] As mentioned above, a loop-shaped drip-proof frame is resin-molded to surround a predetermined area of the resin film to form a watertight state with the resin film, so that water will not enter from the key top side. Moisture and moisture can be blocked out by this drip-proof frame, and the key tops are also molded into a resin film within this drip-proof frame to make them watertight.
This moisture and moisture can be completely blocked from entering the contact area.

Furthermore, since the resin sheet and the drip-proof frame on which the fixed contacts and movable contacts are formed can be mounted in a watertight manner on curved surfaces such as corners of flexible electronic equipment casings, the mounting position can be changed. There are no restrictions.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. 1 to 7 are diagrams showing the structure of a key top, a drip-proof sheet, and a drip-proof frame used in a push-button switch with a drip-proof structure according to the present invention. FIG. 1 is a cross-sectional view of the push-button switch, and FIG. 2 is a switch operating body. 3 is a sectional view taken along line AA in FIG. 2, FIG. 4 is a back view of the switch operating body, FIG. 5 is a sectional view taken along line BB in FIG. ) are views showing the plane, cross section, and back surface of the key top, respectively, and FIG. 7 is a plan view of the resin sheet of the switch section.

In FIG. 1, reference numeral 11 denotes a base whose upper surface, such as a corner of an electronic device housing, is curved. The base 11
Resin sheets 12 and 14 are disposed above and below with a spacer 13 interposed between them. A fixed contact pattern 12a of the switch is formed on the lower resin sheet 12, and a movable contact pattern 14a of the switch is formed on the upper resin sheet 14. The fixed contact 12a and the movable contact 14a face each other.

A click spring 15 is disposed on the upper resin sheet 14, and a key top 18 is disposed on the click spring 15, which is watertightly provided on a resin film 16, as will be described in detail later. . Reference numeral 17 denotes a drip-proof frame provided in a watertight manner on the resin film 16 so as to surround a predetermined area of the film, as will be described in detail later. In addition, number 19 is a curved panel, and the key top 18
The upper part of the panel 19 passes through a hole 20 provided in the panel 19,
exposed at the top. Further, the drip-proof frame 17 and the panel 19 are fitted in a watertight manner by groove fitting, as will be described in detail later. Further, the drip-proof frame 17 is also attached to the base body 11 in a watertight manner.

By pressing the key top 18,
The movable contact 14a comes into contact with the fixed contact 12a. Moreover, as will be detailed later, the key top is attached to the resin film 16 in a watertight manner, and the drip-proof frame 17 is attached to the resin film 16 in a watertight manner.
The structure is such that moisture, humidity, etc. that enter through the holes 20, etc. of the panel 19 do not penetrate into the contact portions made of the resin sheets 12, 13, etc. Hereinafter, the structure of each part of the push button switch having the above structure will be explained in detail.

As shown in FIGS. 2 to 5, a loop-shaped drip-proof frame 1 is attached to the resin film 16 so as to surround a predetermined area thereof.
7 is formed by resin molding on the resin film 16 in a watertight state. Further, a key top 18 is formed in this drip-proof frame 17 in a watertight state with the resin film 16.

As shown in FIG. 5, the drip-proof frame 17 is formed with an upper part 17b and a lower part 17c with a resin film 16 in between, and a long groove 17a having a rectangular cross section is formed on the upper surface of the upper part 17b. A fixing portion 17d for fixing to the base body is integrally formed on the lower surface of the frame 17. Here, the drip-proof frame 17 is formed with a loop-shaped upper part 17b and a loop-shaped lower part 17c sandwiching the resin film 16, and the upper part 17b and the lower part 17c are connected through a hole 21 formed in the resin film 16. Therefore, moisture and moisture will not penetrate between the drip-proof frame 17 and the resin film 16. That is, the space between the resin film 16 and the drip-proof frame 17 has a watertight structure that prevents moisture from penetrating. The drip-proof frame 11 is made of a flexible synthetic resin, such as a styrene elastomer or a polyester elastomer.

As shown in FIG. 6, the key top 18 is formed with a key top part 18b at the upper part and an annular holding part 18c at the lower part with the resin film 16 in between, and further has a lower surface for pressing the movable contact of the switch. A protrusion 18a is formed for this purpose. The key top 12 is made of thermoplastic polycarbonate resin or acrylic resin. Here, in the key top 18, the resin film 16 is sandwiched between the key top part 18b and the annular holding part 18c, and the key top part 18b and the annular holding part 18c are connected to the hole 22 shown in FIG.
Since the key tops 18 and the resin film 16 are only connected through the key top 18, moisture and moisture will not penetrate between the key tops 18 and the resin film 16. That is, the space between the resin film 16 and the key top 18 has a watertight structure that prevents moisture from penetrating.

FIG. 8 is a plan view showing the shapes of the upper and lower resin sheets 12, 14. As shown in the figure, the upper and lower resin sheets 12 and 14 are formed by cutting a single resin sheet, and the upper resin sheet 12 has a fixed contact pattern 12a,
12a, 12a and the fixed contact patterns 12a, 12a,
12a is formed in series, and the lower resin sheet 14 has movable contact patterns 14a, 1
4a, 14a and the movable contact patterns 14a, 14a, 1
Wiring patterns 14b, 14 connected to each of 4a
b, 14b are formed, and a groove 24 is provided between the movable contact patterns 14a and 14a to facilitate mutual bending. Moreover, a notch 23 having substantially the same shape is formed between the upper resin sheet 12 and the lower resin sheet 14, and is open at the locations where the fixed contact pattern 12a and the movable contact pattern 14a are located. The above notch 2
A contact portion is formed by interposing a spacer (not shown) between the upper resin sheet 12 and the lower resin sheet 14 and bending the upper resin sheet 12 and the lower resin sheet 14 at the center point 3 .

The key top 18 is formed, as shown in FIG. 9, by using an upper mold 105 having a cavity 110 having the same shape as the key top portion 18b (see FIG. 6) and an annular holding portion 12c (see FIG. 6). A lower mold 10 having a cavity 111 having the same shape as the projection 18a and a cavity having the same shape as the protrusion 18a.
By sandwiching the resin film 16 between the keys 6 and 6 and injecting the molten resin from the pin gate 107 provided at the upper part of the protrusion 18a of the key top 18, the molten resin is poured into the cavity 110 of the upper mold 105 and the lower part. It flows into the cavity 112 of the mold 106 and also flows into the cavity 111 of the lower mold 106 through the hole 22 of the resin film 16. The key top 18 is formed by solidifying this molten resin.

The drip-proof frame 17 is formed by forming a cavity 112 having the same shape as the frame upper part 17b (see FIG. 5), as shown in FIG.
The resin film 16 is sandwiched between an upper mold 101 having a frame lower part 17c (see FIG. 5) and a lower mold 102 having a cavity 113 of the same shape, and by injecting molten resin from a pin gate 103, the molten resin is poured into a resin reservoir. 23 into the cavity 112 of the upper mold 101, and further passes through the hole 21 of the resin film 16 and flows into the cavity 113 of the lower mold 102. A drip-proof frame 17 is formed so as to surround a predetermined range of the resin film 16 in a state where the resin is individualized.

Next, the installation of the main push button switch to the main body of the device will be explained. First, the resin sheets 12 and 14 on which the fixed contact pattern 12 and the movable contact pattern 14a are formed are placed on the base surface having a curved surface as shown in the figure, with the spacer 13 interposed between the resin sheets 12 and 14, and the notch 23 centered on the base surface. Place the folded item on the Next, the fixing parts 17d (10 pieces in the embodiment) of the drip-proof frame 17 are press-fitted into the fitting holes provided on the surface of the base body.

Here, 2 in the longitudinal direction of the drip-proof frame 17
The reason why the fixed portion 17d on the opposite side is provided is to keep the switch operating body at a constant distance from the base surface having a curved surface. Next, the fitting protrusion 19a provided on the curved panel 19 is fitted into the long groove 17a formed on the top surface of the drip-proof frame 17, completing the installation of the push button switch.

[0023]

As explained above, according to the present invention, a loop-shaped drip-proof frame is resin molded on a resin film so as to surround a predetermined area of the resin film, and is formed in a watertight state with the resin film. This drip-proof frame can block moisture and water that enters from the key top side, and the key top is also molded into a resin film within this drip-proof frame to make it watertight, so this moisture can be blocked. It is possible to provide a push button switch that is excellent in drip-proofing and can completely block the intrusion of water and moisture into the contact portion.

Furthermore, since the resin sheet and drip-proof frame on which the fixed contacts and movable contacts are formed can be installed in a watertight manner on curved surfaces such as corners of flexible electronic equipment casings, the mounting area can be Restrictions become extremely small.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the structure of a push button switch with a drip-proof structure according to the present invention.

FIG. 2 is a plan view of the switch operating body.

FIG. 3 is a sectional view taken along line AA in FIG. 2;

FIG. 4 is a back view of the switch operating body.

FIG. 5 is a sectional view taken along line BB in FIG. 2;

6A, 6B, and 6C are diagrams showing a plane, a cross section, and a back surface of the key top, respectively; FIG.

FIG. 7 is a plan view of a drip-proof resin film.

FIG. 8 is a plan view showing the shapes of upper and lower resin sheets forming the switch section.

FIG. 9 is a diagram for explaining a resin mold of a key top.

FIG. 10 is a diagram for explaining a resin mold of the drip-proof frame.

FIG. 11 is a diagram showing a structural example of a conventional push button switch having a drip-proof structure.

FIG. 12 is a plan view showing the shapes of a conventional rubber packing and a drip-proof sheet.

[Explanation of symbols]

11 Base 12 Upper resin body 13 Spacer 14 Lower resin body 15 Click spring 16
Resin film 17 Drip-proof frame 18 Key top 19 Panel 20 Hole 21 Hole 22 Hole 23 Hole

Claims (1)

[Claims] 1. A push button switch comprising a fixed contact and a movable contact formed on a resin sheet surface and arranged to face each other, and a key top arranged on the movable contact and pressing the movable contact, A loop-shaped drip-proof frame is formed on the resin film by resin molding with a flexible resin material so as to surround a predetermined area of the resin film, and a loop-shaped drip-proof frame is formed within the loop-shaped drip-proof frame. The key top is resin-molded and formed in a watertight state with the resin film to form a switch operating body, and the resin sheet on which the fixed contacts and movable contacts are formed is disposed on a base surface having a curved surface. , the drip-proof frame surrounds at least a portion of the resin sheet where the fixed contact and the movable contact are formed, and the key top is positioned above the movable contact. A push button switch with a drip-proof structure, characterized by a watertight base surface.