JPS6139329A - Keyboard switch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a keyboard switch, and more particularly to a keyboard switch widely used as an input device for information processing equipment, office equipment, industrial equipment, and the like.

[Conventional technology]

Conventionally, this type of keyboard switch has a structure as shown in FIG. The outer edge 7-1 of the leaf spring 7 is in contact with the upper part of the peripheral fixed contact 9-1, 9-2 provided on the lower housing 8.

The plate via has a shape in which the center portion protrudes upward.

As a result, there is a gap between the fixed contact 9-3 and the central fixed contact 9-3. The actuator 5 is inserted along a guide device 6 integrally formed with the lower housing 8, and is thereby able to slide up and down. The lower end of the coil spring 4 pushes the actuator 5 downward.
is inserted inside. A plunger 3 is located at the top of the upper housing 2 to push down the top end of the coil spring 4. The plunger 3 is slidable along the inner circumference of the upper housing 2 in the axial direction. The upper housing 2 and the lower housing 8 are connected to the hook 8-1 of the lower housing 8.
are coupled by engaging with the shoulder 2-1 of the upper housing 2. The key top 1 is press-fitted into the plunger 3 and fixed.

Next, an example of operation will be explained with reference to FIGS. 2(a) and 2(b).

When key top 1 is pressed as shown in Figure 2(b),
The plunger 3 receives a downward load. This load acts on the leaf spring 7 via the coil spring 4 and the actuator 5, thereby causing the leaf spring 7 to bend. That is, the leaf spring 7 deforms so as to protrude downward. Since the outer edges 7-1 and 7-2 of the leaf spring 7 are always in contact with the fixed contacts 9-1 and 9-2 in the peripheral part, the back surface of the leaf spring 7 is in contact with the fixed contact 9-3 in the central part. Then, the fixed contact 9-3 at the center and the fixed contacts 9-1, 9-2 at the periphery are electrically connected to close an electric circuit. When the pressing force of the key top 1 is released, the leaf spring 7 returns to its initial state due to its self-restoring force, and the fixed contact 9-3 in the center and the fixed contacts 9-1, 9-2 in the peripheral part
The electrical circuit is therefore opened.

[Problem that the invention seeks to solve]

According to the above structure, the plunger 3 and the upper housing 2
Since the area between the sliding part and the contact part is open,
Abrasion powder generated when the plunger 3 slides within the upper housing 2 enters the contact portion and tends to cause contact failure.

SUMMARY OF THE INVENTION An object of the present invention is to provide a keyboard switch that prevents abrasion powder generated at the sliding part between the plunger and the housing from entering the contact part and guarantees stable contact function over a long period of time. shall be.

[Means for solving problems]

According to the present invention, a hollow housing, a key top exposed above the housing, and a plunger fixed to a lower part of the key top and slidably incorporated in an upper part of the nose ring in the vertical direction; an actuator that is located inside the housing and receives the pressing force of the plunger via a coil spring; and a guide device that guides the actuator in the vertical direction.

a dome-shaped leaf spring that also serves as a movable contact facing the lower end of the actuator, and a dome-shaped leaf spring installed opposite to the leaf spring;
In the keyboard switch, the guide device includes a cylindrical portion that slidably receives the actuator, and a cylindrical portion that extends in a radial direction from an outer peripheral surface of the cylindrical portion, and a fixed contact that selectively contacts the leaf spring. - A keyboard switch is obtained, which is characterized by having a flange supported by the side wall of the housing.

〔Example〕

Next, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 3 is an exploded perspective view of an embodiment of the keyboard switch according to the present invention.

Figure 4(a) shows the assembled keyboard switch
FIG. 4(b) is a sectional view of the FF state and the same ON state.

Referring to FIGS. 6 and 4, a guide device 11 is provided inside the lower housing 12 and is made separately from the lower housing 12. As shown in FIG. The guide device 11 is.

The actuator 5 is provided in a cylindrical portion 11-1' which receives the actuator 5 so as to be slidable up and down. This cylindrical portion 11-1 plays the same role as the guide device 6 in the conventional example shown in FIGS. 1 and 2. A radially expanding collar portion 11-2 is integrally formed on the outer peripheral surface of the cylindrical portion 11-1. Brim part 11
The outer peripheral end portion of -2 is sandwiched and fixed between the lower end of the upper housing 2 and the upper surface 8-1 of the lower housing 12. As a result, the lower end of the cylindrical portion 11-1 is connected to the lower housing 1.
It is far from the inner base of 2.

Note that explanations of the configuration and operation similar to those of the conventional example shown in FIGS. 1 and 2 will be omitted.

Now, when the plunger 3 is moved up and down by the operation of the key dog 1, the inner surface of the upper housing 2 and the plunger 3
Abrasion powder is generated by sliding. This abrasion powder falls, and most of it accumulates on the upper surface of the collar portion 11-2 of the guide device 11. Therefore, wear particles do not enter the contact portion.

〔Effect of the invention〕

As described above, according to the keyboard switch of the present invention,
Since the contact portion is isolated from the worn portion by the guide device, contact damage caused by wear powder applied to the contact portion is completely eliminated, and the contact function is stable over a long period of time.
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[Brief explanation of the drawing]

Figure 1 is an exploded perspective view of a conventional keyboard switch, Figure 2 is an exploded perspective view of a conventional keyboard switch.
Figures (a) and (b) are longitudinal sectional views of a conventional keyboard switch, Figure 6 is an exploded perspective view of an embodiment of the keyboard switch according to the present invention, and Figure 4 (a). (b) is a longitudinal sectional view of an embodiment of the keyboard switch according to the present invention. 1...Key top, 2...Upper nousing. 3...Plunger, 4...Coil spring. 5... Actuator, 6... Guide device. 7... Leaf spring, 7-1.7-2... Leaf spring outer edge. 7-3...Central part of leaf spring, 8...Lower housing. 9-1.9-2.9-3... Fixed contact, 11... Guide device. 11-1...Cylindrical part, 11-2...Brim part, 12.
...lower howe Fig. 4 Co) Fig. 4(b)

Claims (1)

[Claims] 1. A hollow housing, a key top exposed above the housing, a plunger fixed to the bottom of the key top and slidably built into the top of the housing in the vertical direction, and a plunger inside the housing. , an actuator that receives the pressing force of the plunger via a coil spring, a guide device that guides the actuator in the vertical direction, a dome-shaped leaf spring that also serves as a movable contact facing the lower end of the actuator, and the leaf spring. In the keyboard switch, the guide device includes a cylindrical portion that slidably receives the actuator, and a fixed contact that is installed opposite to the plate spring and selectively contacts the leaf spring. A keyboard switch comprising a radially extending collar supported by a side wall of the housing.