JP2882878B2 - Click spring for switch - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a click spring for a switch, and more particularly, to a click spring for a switch, which is manufactured by pressing a thin metal plate, has a polygonal planar shape, and has a dome portion at the center. The present invention relates to a click spring for a switch having a protruding portion.

(Prior Art) In recent years, circular click springs having a dome portion formed in the center and having a circular planar shape are being used as click contact switches used for numeric keys such as push phones which have become widespread in recent years. .

When such a circular click spring is used as a switch, the vicinity of the top of the dome is pressed to make the dome concave, and the switch is turned on. On the other hand, when the pressing force for pressing the dome is released, the dome returns to the original convex state by the elastic force of the dome itself, and the switch is turned off.

Such a switch using a conventional circular click spring,
In particular, in a switch in which a click spring placed on a printed circuit board is covered with a sheet or the like, it is required to increase the stroke length of the click spring in order to clarify the ON / OFF operation of the switch.

In order to meet such a demand, the present inventors prototyped a click spring shown in FIGS.

The click spring A 'shown in FIGS. 4 and 5 has a dome portion 30 protruding from a metal plate 101 having a substantially triangular planar shape.

At each corner of the metal plate 101 of the click spring A ',
The protruding portion 70 is formed by bending the tip of each corner to the opposite side to the protruding direction of the dome portion 30.

The protrusion 70 is a portion for supporting the click spring A ', and the stroke length H of the click spring A' is defined between the lower surface of the protrusion 70 and the bottom of the concave portion 50 provided near the vertex of the dome 30. It is.

Such a click spring A 'is generally manufactured by press working, and as shown in FIG. 3, a plurality of click springs A' are connected to a thin metal plate 100 by hanging portions 90. , When mounted on the device,
90 ... are cut.

(Problems to be Solved by the Invention) Click spring A 'having a substantially triangular planar shape shown in FIGS. 3 to 5 (hereinafter sometimes referred to as a triangular click spring).
The stroke length H can be increased as compared with a conventional circular click spring in which the planar shape is circular and it is difficult to form the protrusion 70.

However, it was found that the triangular click springs shown in FIGS. 3 to 5 cracked in a shorter time than the circular click springs and were inferior in durability.

In particular, the triangular click spring is indicated by, for example, an X mark in FIG.
It was also found that when a load (eccentric load) was repeatedly applied to the position 210, cracks were likely to occur early.

When the click spring in which such cracks are generated presses the dome portion to be in a concave state, even if the pressing force for pressing the dome portion is released, it is difficult for the dome portion to return to the original convex state. Devices that use springs cannot be used.

For this reason, a click spring having poor durability significantly reduces the reliability of the device in which the click spring is used.

Accordingly, an object of the present invention is to provide a click spring having a polygonal planar shape with significantly improved durability even when an eccentric load is applied.

(Means for Solving the Problems) The present inventors first observed the appearance of cracks in the triangular click spring.
(FIG. 4), it was found that it occurred in the direction of the concave portion 50 of the dome portion 30 from the vicinity of FIG.

The protruding piece 190 is located near the center between the corners where the protruding portions 70 are formed, and is a mark of the hanging portion 90 for connecting the triangular click spring to the thin metal plate 100 as shown in FIG. .

Based on such findings, the present inventors consider that the position of the projecting piece 190 is important in the occurrence of cracks, and have studied variously the position of the hanging portion 90, and as a result, have reached the present invention.

That is, the present invention is formed by pressing a thin metal plate, the hanging portion extending from the thin metal plate is cut and separated from the thin metal plate, the planar shape is polygonal, and the dome portion is formed at the center. In the projecting switch click spring, at least three corners of the click spring are formed with projecting portions projecting in opposite directions to the projecting direction of the dome portion so that the click spring can be supported. And the hanging portion extending near the corner portion is cut at a position close to the click spring.

In the present invention having such a configuration, the click spring can be stably supported by the projection by setting the planar shape of the click spring to be substantially triangular.

(Operation) Although the detailed reason why the durability of the polygonal click spring can be remarkably improved by the present invention has not been clarified, it is presumed as follows.

In other words, as shown in FIG. 3, when the click spring A 'is connected to the thin metal plate 100 by the thin hanging portions 90, stress is concentrated on the hanging portions 90 by pressing or the like. However, it is considered that some kind of defect has occurred in the vicinity of the protruding piece 190, which is a connecting portion between the click spring A 'and the hanging portion 90.

Therefore, when the dome portion 30 of the click spring A 'moves up and down, the protruding piece 190 is located near the center between the corners where the amount of displacement is the largest on the periphery of the click spring A'. Then, a large displacement is repeatedly applied to the vicinity of the protruding piece 190.

For this reason, the stress concentration generated due to the repetition of the defect and the large displacement that have already occurred in the vicinity of the projecting piece 190 rapidly expands, and a crack occurs.

In this regard, in the click spring A of the present invention, the position where the click spring A is connected to the hanging portion 9 is located near the corner where the projection 7 having the smallest displacement is provided.

As a result, a large amount of displacement is not repeatedly applied to the vicinity of the projecting piece 19, so that stress concentration occurring near the projecting piece 19 is eliminated, and the durability of the click spring A can be improved.

(Example) The present invention will be described in further detail with reference to the drawings.

FIG. 1 is a front view showing an embodiment of the present invention, in which a plurality of click springs A are formed in a longitudinal direction of a metal thin plate by pressing a band-shaped thin metal plate 10. As shown in FIG.

The click spring A has a substantially triangular front shape, and is connected to a thin metal plate 10 via a hanging portion 9.

Like the click spring shown in FIGS. 3 to 5, the click spring A has a dome portion 3 projecting from a thin metal plate 10 having a substantially triangular planar shape.

Further, at each corner of the thin metal plate 10 of the click spring A, a protrusion 7 is formed by bending the tip of each corner to the opposite side to the direction in which the dome portion 3 projects.

The protrusion 7 is a portion that supports the click spring A, and the stroke length H of the click spring A is between the lower surface of the protrusion 7 and the bottom of the concave portion 5 provided near the vertex of the dome portion 3. .

The small holes 12 shown in FIG. 1 are positioning holes for positioning the strip-shaped metal sheet 10.

In the click spring A of the present embodiment, the three hanging portions 9 for connecting the thin metal plate 10 are the outer peripheral edges of the click spring A and the corners where the respective protrusions 7 are formed. It is connected near.

When each of the click springs A shown in FIG. 1 is mounted on a device or the like, as shown in FIG. 2, the hanging parts 9 are cut off, and the click springs A and the hanging parts 9 are formed. The projecting pieces 19... That were the connecting portions remain as traces of the hanging portions 9.

An eccentric load is applied to the click spring A of FIG. 2 separated from the metal sheet 10 in this manner, that is, a load is applied to the position indicated by the mark 21 in FIG. The test was performed.

As a result, the number of vertical movements of the click spring A shown in FIG. 2 could be approximately three times the number of vertical movements of the click spring A ′ shown in FIG. 4 in the same durability test.

In the above-described embodiment, the click spring A having a substantially triangular planar shape has been described as an example. However, the planar shape may be a polygon having more than a triangle.

(Effect of the Invention) Since the click spring of the present invention has remarkably improved durability, even if the click spring is mounted on a device such as a push phone and an eccentric load is applied, it is possible to avoid a situation where the click spring is cracked. The reliability of the device can be improved.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of the present invention, and FIG.
FIG. 3 is a front view showing a click spring taken out by cutting the hanging portion 9 shown in FIG. 3, FIG. 3 is a front view showing a conventional click spring, and FIG. 4 is a drawing taken out by cutting the hanging portion 90 shown in FIG. FIG. 5 is a front view showing the click spring, and FIG. 5 is a cross-sectional view of the click spring shown in FIG. In the figure, A: click spring, 3: dome part, 5: concave part, 7
... Projecting part, 9 ... Hanging part, 10 ... Metal sheet, 12 ... Positioning hole, 19 ... Projecting piece, 21 ... Eccentric load position.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01H 11/00 H01H 13/48 H01H 5/30

Claims (2)

(57) [Claims] 1. A sheet metal formed by pressing a sheet metal,
A switch click spring having a polygonal planar shape and a dome portion protruding at the center portion, wherein the hanging portion extending from the metal sheet is cut and separated from the metal sheet, and the click spring can be supported. As described above, at each of at least three corners of the click spring, a protruding portion that protrudes in a direction opposite to a protruding direction of the dome portion is formed, and the suspension extending near the corner is provided. A click spring for a switch, wherein a portion is cut at a position close to the click spring. 2. The click spring for a switch according to claim 1, wherein the planar shape of the click spring is substantially triangular.