JPH0241791Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an improvement of an illuminated push button switch.

[Conventional technology] Conventionally, when pressing the key top, the LED
Illuminated push-button switches are known that indicate their operating status by lighting up an illuminated lamp.

As shown in FIG. 1, for example, such an illuminated push button switch has one contact mounting part 2 formed in a dome shape made of a rubber material and which comes into contact with one side of the bottom surface of a key top 1. There is one in which an illumination lamp 3 is disposed in a recess that opens at the bottom of the other side of the lamp. The contact mounting portion 2 is provided with a movable contact, and a fixed contact is provided at a position facing and separated from the movable contact.

In this case, in order to prevent the light from the illumination lamp 3 from being blocked, the contact mounting portion 2 is arranged at a position offset from the center of the key top pressing surface.

Then, by pressing the key top pressing surface, the contact mounting portion 2 is bent and deformed, the movable contact comes into contact with the fixed contact, and the illumination lamp 3 is turned on.

[Problem to be solved by the invention] However, because the center position 2c of the contact mounting part 2 is deviated from the center position 1c of the key top 1 due to restrictions on the mounting position of the illumination lamp 3,
When the outer surface of the key top 1 is pressed (from the top to the bottom in the figure), the key top 1 tilts toward the illumination lamp 3 and its operating direction deviates from the operating center line 2c of the contact mounting portion 2. This has resulted in the problem that the movable contact shifts laterally, making contact with the fixed contact unstable.

This invention was made in view of the above problems, and its purpose is to make the key top tilt by aligning its operating center direction with the operating center line of the contact mounting part when the key top is pressed. To provide a push button switch with illumination which prevents the light from falling off.

[Means for Solving the Problems] In order to achieve the above-mentioned problems, the illuminated push button switch according to this invention has an opening in the bottom surface for accommodating the illumination lamp at the lower part of the pressing surface at a position offset from the center. a key top provided with a recess to press the key top; a movable contact that is pushed down by the pressure of the key top and comes into contact with a fixed contact; and two contact attachments that are formed of a dome-shaped rubber member and that come into contact with the bottom surface of the key top. , the contact mounting portions are arranged on a straight line passing through the center of the pressing surface with the recess sandwiched therebetween, and each repulsive force against the pressing force when pressing the key top is directed toward the center of the pressing surface. It is characterized by being placed in a position that is inversely proportional to the distance from.

[Function] With the illuminated push button switch according to this invention, the pressed key top moves without tilting due to the balance between the pressing force and the repulsive force applied to each of the two contact mounting parts, resulting in stable pressing operation. Become.

[Example] Hereinafter, an example of the illuminated push button switch according to this invention will be described based on the drawings.

In FIG. 2, the key top 4 has a recess for accommodating an illumination lamp 6 on the bottom surface of one side of the key top 4, which is a lower portion offset from the center of the key top pressing surface. The head of the key top 4 is inserted into the sliding hole 5a formed in the frame 5, and the flange portions 4a and 4b abut against the peripheral edge of the sliding hole 5a, so that the key top 4 slips out upward. It prevents In this flange portion, one flange portion 4a is formed to be slightly wider than the other flange portion 4b.

A rubber sheet 9 is attached to the printed circuit board 7 to which the illumination lamp 6 is fixed, and this rubber sheet 9 has dome-shaped rubber members formed at symmetrical positions with respect to the center of the illumination lamp 6. Contact mounting portions 10 and 11 are provided. In addition, the illumination lamp 6 housed in the recess
is arranged at a position 3c separated by a distance from the center position 4c of the key top 4, so that the illumination light from the illumination lamp 6 can be seen through the transparent part 4A.

The two contact mounting parts 10 and 11 are on a straight line passing through the center of the pressing surface of the key top 4 with the recess in between, and are spaced apart from the center position 4c of the key top 4 by a distance a ₁ and a ₂ , respectively. Position 10c, 11c
The movable contacts 12 and 13 are provided on the inner surface of each contact mounting portion 10 and 11, respectively. Furthermore, the movable contacts 12 and 13 are in contact with the bottom surface of the key top 4, and are pushed down by the pressed bottom surface of the key top 4, thereby
A printed circuit board 7 faces each movable contact 12, 13.
The fixed contacts 14 and 15 provided thereon are contacted, and the illumination lamp 6 is turned on.

In this way, when the key top 4 is pressed or released, the skirt portions of the contact mounting portions 10 and 11 are elastically compressed or returned, thereby causing the movable contact 1
2 and 13 and fixed contacts 14 and 15 are brought into contact and separated from each other. In this case, the two movable contacts 12 and 13 are
Fixed contact 14, 1, one of which faces this
By contacting or separating from 5, a switching operation of the contact can be performed. Note that 8 is a hole formed in the rubber sheet 9 in order to attach the terminal portion of the illumination lamp 6 to the printed circuit board 7.

In addition, the contact mounting portion 1 formed on the rubber sheet 9
0 and 11 are asymmetrical, for example, the thicknesses t ₁ and t ₂ of each skirt portion are made thicker than the other. As a result, when the key top 4 is pushed in, the repulsion force is greater at the contact mounting portion 11 than at the contact mounting portion 10, for example.

To explain this relationship more specifically, if the repulsive force of the contact mounting portion 10 is g ₁ and the repulsive force of the contact mounting portion 11 is g ₂ , then g ₁ /g ₂ = a ₂ /a ₁ holds true. In other words, the distance from the center position 4c of the key top 4 to each contact mounting portion 10, 11 is set so that each repulsive force against the pressing force when pressing the key top 4 is inversely proportional to the distance from the center of the pressing surface of the key top 4.
a ₁ , a ₂ , or each repulsive force g ₁ , g ₂ is set.
The ratio g ₁ /g ₂ of such repulsive force is determined at each position 10c, 1 when the center position 4c of the key top 4 is pressed.
It coincides with the pressure ratio acting on 1c. In addition, when setting these repulsive forces, contact mounting part 10,
Not only the thickness of 11 but also the shape may be changed.

Next, the operation of the illuminated push button switch shown in the above embodiment will be explained.

By pressing the key top 4 with the center of action near the center position 4c, the contact mounting portion 10
The pressing force distributed to the contact mounting portion 11 is smaller than that of the contact mounting portion 11, and the repulsive force of the contact mounting portion 10 is correspondingly smaller than that of the contact mounting portion 11.
Therefore, the operating forces are balanced and the key top 4 operates smoothly. At this time, each contact mounting portion 10,
The 11 compression amounts are equal to each other.

In this way, the two contact mounting parts 10 and 11 are
By arranging the key top 4 in a position where its operating force (repulsion force) is balanced, the key top 4 does not tilt and moves in parallel, preventing lateral displacement, and the movable contacts 12, 13 and fixed contacts 14, 15 are in reliable contact, allowing switch operation. becomes stable.

[Effects of the invention] As explained above, the illuminated push-button switch according to the invention has a recess opening at the bottom for accommodating the illumination lamp at the lower part of the pressing surface at a position offset from the center. The key top has a movable contact that is pushed down by the pressure of the key top and comes into contact with a fixed contact, and is formed of a dome-shaped rubber member and has two contact attachment parts that come into contact with the bottom surface of the key top, Both of the contact mounting portions are arranged on a straight line passing through the center of the pressing surface across the recess, and each repulsive force against the pressing force when pressing the key top is inversely proportional to the distance from the center of the pressing surface. It is characterized by its location.

Therefore, when the key top is pressed, the direction of its operating center coincides with the operating center line of the contact mounting part, and the key top moves without tilting, making it possible to perform the pressing operation of the key top in a well-balanced manner, resulting in smooth operation. Switch operation is possible.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional illuminated push button switch, and FIG. 2 is a sectional view of an illuminated push button switch according to this invention. 4...Key top, 6...Illumination lamp, 10,
11... Contact mounting part, 12, 13... Movable contact,
14, 15...Fixed contacts.

Claims (1)

[Claims for Utility Model Registration] A key top provided with a recess opening at the bottom for accommodating an illumination lamp in the lower part of the pressing surface at a position offset from the center, and a fixed contact that is pushed down by the pressure of the key top. The key top has a movable contact that contacts the key top, and two contact mounting portions that are formed of a dome-shaped rubber member and that contact the bottom surface of the key top, and the two contact mounting portions sandwich the recess. An illuminated push button characterized in that the push button is arranged on a straight line passing through the center of the pressing surface and at a position where each repulsive force against the pressing force when pressing the key top is inversely proportional to the distance from the center of the pressing surface. Switch.