JPH039219Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to push-button switches used in various input devices such as personal computers and word processors, and more particularly relates to improvements in push-button switches having coil springs. be.

(Prior Art) Among the push button switches used in the above-mentioned various input devices, there is a push button switch having a coil spring, and one example thereof is, although not specifically shown,
There is a structure in which a guide portion of a coil spring is integrally formed with a stem that is supported in a case so as to be movable up and down, and an end portion of, for example, a coil spring that applies upward return force to the stem is attached to the guide portion.

In a push button switch having such a structure, when the end of the coil spring is attached to the guide section, the guide section 2 of the stem 1 is attached as shown in FIG.
Generally, the coil spring 3 was attached by pushing the coil spring 3 in from the outside through a pushing jig 4 and tightly fitting the end 3a of the coil spring 3 to the root 2a of the guide part 2. It goes without saying that the inner diameter of the coil spring 3 is set to be smaller than the outer diameter of the root 2a of the guide portion 2 in the installation by such a strong fit.

(Problems to be Solved by the Invention) However, in this conventional mounting structure, when the end portion 3a of the coil spring 3 is tightly fitted into the guide portion 2,
Basically, it is simply a matter of obtaining a fitted state, so it cannot be denied that the mounting strength naturally decreases.

Moreover, in the case of strong fitting, the allowable dimensional error range between the outer diameter of the root 2a of the guide part 2 and the inner diameter of the coil spring 3 must be made as small as possible, so component accuracy is required and manufacturing process is extremely difficult. It also has some problems.

In addition, when pushing the end 3a of the coil spring 3 to the base 2a of the guide part 2, it is necessary to individually adjust the pushing amount of the pushing jig 4, but depending on the wire diameter of the coil spring 3, the number of turns, and the stem 1. If the dimensions, etc. of It was hot.

(Means for Solving the Problems) The present invention was developed to effectively solve the above-mentioned conventional problems, and includes integrally forming the guide portion of the coil spring on the resin stem. A push button switch having a structure for attaching the end of the coil spring to the guide part is used as the front bank, and the end of the coil spring is fixed to the guide part of the stem by heat welding.

(Function) According to the present invention, since the end of the coil spring is fixed to the guide part of the stem by heat welding, the mounting strength is significantly improved, and the inner diameter of the coil spring and the outer diameter of the guide part are Since dimensional accuracy between diameters is not an issue, not only is the conventional part precision required in terms of manufacturing processing, but also the end of the coil spring can be reliably and easily pushed to the base of the guide part of the stem. is also possible.

(Example) Hereinafter, the present invention will be described in detail based on an example in which the present invention is applied to a push button switch shown in FIG.

The push button switch shown in FIG.
For example, a stem 13 made of resin is supported in a case 12 provided on a panel 11 such as a keyboard panel so as to be movable up and down, and a membrane switch 14 is disposed below the stem 13. In between, a first coil spring 15 that constantly urges the stem 13 upward and a second coil spring 16 that presses the contact portion of the membrane switch 14 as the stem 13 descends are interposed.

Further, as shown in the figure, the first coil spring 15 is installed between the recess 13a in which the stem 13 is formed and the receiving portion 12a of the case 12, and the second coil spring 16 is compared with the free length of the first coil spring 15. death,
The upper end portion 16 is approximately half the size of the
Only the part a is attached to the guide part 17 integrally formed in the recess 13a of the stem 13, and the lower end part does not come into contact with the contact part of the membrane switch 14 when the stem 13 is raised. There is.

Therefore, to briefly explain the operation of such a push button switch, when a key top (not shown) provided on the stem 13 is pressed, the stem 13 initially descends while compressing only the first coil spring 15. However, when a certain amount of force is applied, the second coil spring 16 comes into contact with the contact portion of the membrane switch 14 and is compressed, so that the contact portion of the membrane switch 14 is compressed by the compression spring pressure of the second coil spring 16. Upon contact, the switch turns on, and when the pressure on the key top is released, each coil spring 1
At the same time as the stem 13 rises due to the spring pressure of 5 and 16, the lower end of the second coil spring 16 also separates from the membrane switch 14, so that the switch is automatically turned off.

In this embodiment, when the upper end portion 16a of the second coil spring 16 is attached to the guide portion 17 of the stem 13 under such a configuration, the upper end portion of the coil spring 16 is attached via a heat welding jig to be described later. 16a is fixed to the base 17a of the guide portion 17 by heat welding.

To explain this specifically, the second coil spring 1
6, the inner diameter of the guide portion 17 is the same as before.
If the outer diameter of the second coil spring 16 is smaller than the outer diameter of the second coil spring 7a, as shown in FIG. After fitting, a pair of heat welding jigs 18
Each of the tip heating parts 18a connects the upper end part 16a of the coil spring 16 to two opposing parts of the guide part 17.
At the same time, the tip heating section 18a melts the wall surface of the guide section 17, thereby causing the upper end portion 16a of the coil spring 16 to press against the wall surface of the base 17a.
is fixed to the base 17a of the guide portion 17.

Conversely, the inner diameter of the second coil spring 16 is
If the diameter is larger than the outer diameter of No. 7, the third
As shown in the figure, the large diameter upper end 16 of the coil spring 16
a loosely fitted to the guide portion 17, and at least one portion of the upper end portion 16a in the loosely fitted state is attached to the root 17 of the guide portion 17 via the heat welding jig 18.
Fix it to the wall of a by heat welding. Note that when the large-diameter coil spring 16 is loosely fitted into the guide portion 17, a conventional pushing jig is used or it is done manually.

Therefore, in any case, in this example,
The second portion attached to the guide portion 17 of the stem 13
The upper end 16a of the coil spring 16 is connected to the guide portion 17.
Since it is fixed by heat welding to the coil spring 16, not only the mounting strength is naturally improved, but also the coil spring 16
Since the dimensional accuracy of the inner diameter of the guide portion 17 and the outer diameter of the root 17a of the guide portion 17 is not a problem, the allowable dimensional error range is also expanded, and part precision is not required in terms of manufacturing processing.

As explained in FIG. 3, this makes it possible to attach a coil spring 16 with a larger diameter than the outer diameter of the guide part 17 to the guide part 17, and also makes it possible to use such a large diameter coil spring 16. This makes it possible to lightly and reliably push the guide portion 17 up to the base 17a without using a conventional pushing jig, without using a reaction force. Furthermore, even if a pushing jig is used, there is no need to adjust the pushing amount of the pushing jig each time as in the conventional case.

(Effects of the invention) As described above, the present invention provides a push button switch having a structure in which a guide portion of a coil spring is integrally formed on a resin stem, and an end portion of the coil spring is attached to the guide portion. is fixed to the guide part of the stem by heat welding, which significantly improves the mounting strength compared to conventional methods, and also solves the problem of dimensional accuracy between the inner diameter of the coil spring and the outer diameter of the guide part. Therefore, not only is the conventional part precision not required in terms of manufacturing processing, but it also becomes possible to reliably and easily push the end of the coil spring to the base of the guide portion of the stem.

Therefore, the present invention can ultimately ensure stable operation of a push button switch having a coil spring.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the main parts of a push button switch according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing a state in which the end of a coil spring having a diameter smaller than the outer diameter of the guide part is fixed by heat welding. Figure 3 is an explanatory diagram showing how the end of a coil spring with a diameter larger than the outside diameter of the guide part is fixed by heat welding, and Figure 4 shows the conventional mounting state in which the end of the coil spring is attached to the guide part. FIG. 13... Stem, 16... Second coil spring (coil spring), 16a... Upper end portion, 17... Guide portion, 17a... Root, 18... Heat welding jig, 18
a...Tip heating section.

Claims (1)

[Scope of utility model registration request] In a push button switch having a structure in which a guide portion of a coil spring is integrally formed on a resin stem and an end portion of the coil spring is attached to the guide portion, the end portion of the coil spring is fixed to the guide portion of the stem by heat welding. A push-button switch that is characterized by