JPH0227469Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a push button switch mounting structure for attaching a key top to a stem for operating a switch element.

As push button switches used in keyboards and the like, for example, the ones shown in FIGS. 1 to 3 are considered. In FIG. 1, 1 is a case, and this case 1 has an element mounting hole 2 and a stem insertion hole 3 formed therein. The element mounting hole 2 and the stem insertion hole 3 communicate with each other via a slit 4 extending vertically. 5 is a switch element mounted in the element mounting hole 2. This switch element 5
The device includes an element body 6, a movable contact plate 7 and a fixed contact plate 8 attached to the element body 6, and a leaf spring 9 attached to the element body 6. Note that the movable contact plate 7 and the fixed contact plate 8 have terminals 1
0 and 11 are provided integrally with each other, and the plate spring 9 is provided with a pressing piece 9a for pressing the movable contact plate 7. In the figure, 12 is a spring, 13 is a stem, 14 is a lid, and 15 is a key top.

In a push button switch equipped with such parts, the switch element 5 is fitted into the element mounting hole 2, the spring 12 and the stem 13 are inserted in this order into the stem insertion hole 3, and then the cover body 14 is inserted as shown in FIG. By attaching it to the upper opening end of case 1 as shown in
Each component is assembled into the case 1. The stem 13, which penetrates the lid body 14 and projects in and out of the case 1, is integrally provided with a protrusion 16 for operating a pressing piece.
When the pressing piece 9a is displaced against the spring force of the projection 16, the pressing piece 9a is bent toward the movable contact plate 7, and the movable contact plate 7 is bent by the pressing piece 9a, and the fixed contact plate 8 is bent. It is becoming more and more likely that people will be turned away from the government. Therefore, the push button switch shown in FIG. 1, which has a normally closed contact, is turned off by pressing the stem 13 in the axial direction (entering operation), and the spring force of the spring 12 returns the stem 13 to its original state (extracting operation). Then it becomes ON state.

By the way, stem 1 of such a push button switch
The end protruding from the case 1 of No. 3 has an end surface 13a.
A mounting hole 17 is formed that opens to the bottom. Also,
As shown in FIG. 3, a protrusion 19 (the other not shown) is formed on the opposing walls 18, 18 of the mounting hole 17, and a prismatic mounting shaft 20 is integrally formed in the center of the key top 15. It is provided. Therefore, by fitting the mounting shaft 20 into the mounting hole 17, the lower part of the skirt part 15a of the key top 15 covers the upper part of the case 1, and the height of the push button switch can be lowered. By using this in the keyboard, the keyboard can be made thinner.

However, since the attachment shaft portion 20 and the stem 13 are fixed only by the frictional fixation force between the attachment shaft portion 20 and the protrusion 19, the fixation force of the attachment shaft portion 20 to the stem 13 is relatively small. As a result, in a push button switch with a large key, that is, a large key top, the mounting shaft 20 is attached to the end of the key top in the mounting hole 1.
Even if a small force is applied in the direction of thrusting from 7, a large force is applied to the mounting shaft 20 due to the lever principle, so there is a risk that the key top 15 may easily come off from the stem 13.

This idea applies a large frictional fixing force between the key top's mounting shaft and the stem's mounting hole.
To provide a key top mounting structure for a push button switch which prevents the key top from easily coming out of a stem mounting hole even in a large key push button switch.

Based on this purpose, this invention provides a stem that penetrates a case and protrudes into and out of the case, and that operates a switch element within the case by moving the stem forward and backward in the axial direction. A mounting structure for a key top of a push button switch, wherein a mounting hole opening to the end surface is formed in the end protruding from the case, and a prismatic mounting shaft integral with the key top is fitted and fixed into the mounting hole. , a flat mounting protrusion protrudes from the bottom of the mounting hole to form the mounting hole in an annular shape; ribs extending along the side edges are provided on both sides of the mounting protrusion; A protrusion is provided on both sides, a protrusion is provided on a portion of the inner surface of the mounting hole that corresponds to the protrusion, and a fitting hole that opens at the end face is formed in the mounting shaft so that the mounting shaft becomes a rectangular cylinder. By press-fitting the mounting shaft portion and the mounting protrusion into the mounting hole and the fitting hole, respectively, the rib and the inner surface of the fitting hole are frictionally engaged, and the rectangular cylindrical shape A push button switch in which the side part of the mounting shaft is held between the two protrusions to create a large frictional resistance between the mounting shaft and the inner surface of the mounting hole, thereby fixing the key top to the stem. Key top mounting structure.

This invention will be explained below based on FIGS. 4 to 8. In this description, parts or members that are the same as or equivalent to those of the prior art are given the same reference numerals and redundant description will be omitted.

In FIG. 4, the stem 13 has an oval cross-sectional profile. On both sides of the stem 13, through holes 21, 21 are formed as shown in FIGS. 5 and 6, which open to the upper and lower end surfaces 13a, 13b. The bottom wall 22 of the mounting hole 17 has the mounting hole 17
and communication holes 23, 2 that open to the through holes 21, 21.
3 are formed along the opposing walls 18,18.

A mounting protrusion 24 is integrally formed in the center of the bottom wall 22. The attachment protrusion 24 has an elongated and flat cross-sectional shape as shown in FIG. 5, and extends to the same height as the end surface 13a of the stem 13. On both sides of the mounting projection 24, ribs 25, 25 and 26, 26 parallel to the axis of the stem 13 are integrally formed along the side edges as shown in FIGS. Both sides 24a, 2
4a has protrusions 27, 2 opposite to the protrusions 19, 19.
7 are integrally formed. Moreover, rib 25,
The cross-sectional contours of the protrusions 25, 26, and 26 are formed in a circular arc shape, and the vertical cross-sectional contours of the protrusions 27 and 27 are formed in a circular arc shape. Note that the mounting hole 17 is the mounting protrusion 2.
4, it is formed into an annular shape.

Further, the mounting shaft portion 20 of the key top 15 is formed with a fitting hole 28 that opens at the end surface 20a. By providing this fitting hole 28, the mounting shaft portion 20 is formed into a rectangular tube shape. And the eighth
As shown in the figure, the mounting shaft 20 is press-fitted into the mounting hole 17, and the fitting hole 28 has a mounting protrusion 2.
4 is press-fitted.

Next, the function of the key top mounting structure of the push button switch having such a configuration will be explained.

In such a mounting structure, key top 1
The mounting shaft portion 20 on the 5 side is held between the protrusions 19 and 19, and the side portion of the mounting shaft portion 20, that is, the opposing wall 20
b, 20b are held between the protrusions 19, 27 and 19, 27, respectively. In other words, the protrusion 19,1
9 is in elastic contact with the outer surfaces of the opposing walls 20b, 20b, and the protrusions 27, 27 are in contact with the inner surfaces of the opposing walls 20b, 20b. As a result, the protrusions 19, 19, 2
A frictional fixing force is generated between 7 and 27 and the opposing walls 2b and 20b. Moreover, four ribs 25,2
5, 26, 26 are in elastic contact with the inner surface of the fitting hole 25 of the mounting shaft portion 20, so each rib 25, 2
A frictional fixing force is also generated between 5, 26, 26 and the inner surface of the fitting hole 28. Therefore, key top 1
Since a large frictional fixing force is generated between the mounting shaft portion 20 on the 5 side and the inner surface of the mounting hole 17 of the stem 13, the key top 15 is securely and firmly fixed to the stem 13. A small force acting on the end of the stem 1 causes the mounting shaft 20 to
It will not come out from the fitting hole 3.

As explained above, this invention includes a stem that penetrates a case and protrudes into and out of the case, and that operates a switch element inside the case by moving the stem forward and backward in the axial direction. A mounting structure for a key top of a push button switch, wherein a mounting hole opening to the end face is formed in an end protruding from a case, and a prismatic mounting shaft integral with the key top is fitted and fixed into the mounting hole, A flat mounting protrusion is protruded from the bottom of the mounting hole to form an annular shape, and ribs extending along the side edges are provided on both sides of the mounting protrusion. A protrusion is provided on the surface, a protrusion is provided on a portion of the inner surface of the mounting hole corresponding to the protrusion, and a fitting hole is formed in the mounting shaft portion to open at an end surface, so that the mounting shaft portion is shaped like a rectangular tube. By press-fitting the mounting shaft portion and the mounting protrusion into the mounting hole and the fitting hole, respectively, the rib and the inner surface of the fitting hole are frictionally engaged, and the rectangular tube-shaped A side portion of the mounting shaft portion is held between the two protrusions to create a large frictional resistance between the mounting shaft portion and the inner surface of the mounting hole,
Since the key top of the push button switch has a mounting structure in which the key top is fixed to the stem,
Even in the case of a large key push button switch, the key top can be surely prevented from easily coming off from the mounting hole of the stem.

[Brief explanation of the drawing]

Figure 1 is an exploded perspective view showing an example of a push button switch, Figure 2 is a perspective view showing a state in which parts other than the key top in Figure 1 are assembled, and Figure 3 is a partially broken view of the stem in Figure 2. FIG. 4 is a partially exploded perspective view showing the relationship between the assembly and the key top; FIG. 4 is a partially exploded perspective view similar to FIG. 3 of the push button switch according to this invention; FIG. 5 is a plan view of the stem in FIG. 4; Figure 6 is a sectional view taken along the - line in Figure 5, Figure 7 is a sectional view taken along the - line in Figure 5, and Figure 8 is a sectional view showing the key top attached to the stem in Figure 4. be. 1... Case, 5... Switch element, 13...
Stem, 13a... end face, 15... key top,
17...Mounting hole, 19...Protrusion, 20...Mounting shaft, 20a...End face, 22...Bottom wall, 24...Mounting protrusion, 25, 26...Rib, 27...Protrusion,
28... Fitting hole.

Claims (1)

[Scope of claim for utility model registration] Penetrating the case and protruding into and out of the case,
and a stem that operates a switch element in the case by moving forward and backward in the axial direction,
A mounting structure for a key top of a push button switch, wherein a mounting hole opening on the end face is formed in the end of the stem protruding from the case, and a prismatic mounting shaft integral with the key top is fitted and fixed into the mounting hole. A flat mounting protrusion is protruded from the bottom of the mounting hole to form the mounting hole in an annular shape, and ribs extending along the side edges are provided on both sides of the mounting protrusion, and the mounting protrusions are provided on both sides of the mounting protrusion, and a protrusion is provided on a portion of the inner surface of the mounting hole that corresponds to the protrusion, and a fitting hole is formed in the mounting shaft portion at an end face thereof, so that the mounting shaft portion is is formed into a rectangular tube shape, and the mounting shaft portion and the mounting protrusion are press-fitted into the mounting hole and the fitting hole, respectively, thereby frictionally engaging the rib and the inner surface of the fitting hole, and A side part of the rectangular cylindrical mounting shaft is held between the two protrusions to create a large frictional resistance between the mounting shaft and the inner surface of the mounting hole, thereby fixing the key top to the stem. The key top mounting structure of a push button switch is characterized by: