JPS61165917A - 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 the Invention This invention relates to a keyboard switch for a personal computer or the like.

Prior Art A conventional keyboard switch of this type had a structure as shown in FIG.

That is, the case 1 is provided with a boss 1a for fixing the printed circuit board 2 with screws 3, and the case 1 is connected to the printed circuit board 2 on which the rubber sheet 4, which has a hole 4a penetrating the boss 1a' and has carbon contacts 2a printed thereon, is connected to the case 1. sandwiched between the carbon contact 4b of the rubber sheet 4 and the carbon contact 2a of the printed circuit board 2,
It is configured such that a switching operation can be performed by operating the button portion 4c of the rubber sheet 4 by external force.

Problems to be Solved by the Invention However, with this type of structure, there is a limit to securing the insulation distance against static electricity, and when designing a printed circuit board, it is difficult to set up live parts (patterns, electrical components). There were problems such as being subject to restrictions.

This is due to the following reasons.

In other words, when your hand touches the button part 4C of the rubber sheet 4, static electricity will spread over the shortest distance (...
(indicated by ...). Therefore, it is set to printed circuit board 2. The carbon contact 2b and the electrical component 2C must be set outside the range of φD to ensure an insulation distance, which limits the high-density mounting of the printed circuit board 2.

Furthermore, as a conventional example of this type, as shown in FIG. 7, there is a case in which a cylindrical portion 4d of a rubber sheet 4 is provided around the boss 1a of the case 1, but the insulation distance is changed from the hypotenuse of the previous example.
In this case, it is necessary to secure a constant value for the S dimension in the figure, which has disadvantages such as being limited in terms of space and affecting the feeling. Furthermore, even with the combination of rubber sheet 4 and button 10 shown in FIG. 8, the insulation distance is the same as that shown in FIG. do not have.

Further, as shown in FIG. 9, between the boss 1a of the case 1 and the printed circuit board 2, a cylindrical rib 4e is provided at the periphery of the boss hole of the rubber sheet 4, protruding toward the side opposite to the button part 4C, and the printed circuit board 2 In some cases, a spacer 11 is provided for the receiver and the seat for the screw 3.

In this specification, compared to the first conventional example, the insulation distance is increased by the height of the protruding cylindrical lip 4, i.e., the height of the printed base &
Although it is possible to secure twice the thickness (thickness of 2), an extra component called the spacer 11 is required.

Therefore, the present invention provides a keyboard switch that can secure a larger insulation distance without changing the conventional design or number of components, and can alleviate the restrictions on high-density mounting on printed circuit boards.

Means for solving the problems and technical means of the present invention for solving the above problems are as follows:
At least one stepped portion is provided on the periphery of the screw hole in the boss of the case, and a stepped portion is also provided in the boss hole portion of the rubber sheet.

action The effect of this technical means is as follows.

In other words, a large insulation distance can be secured without changing the conventional design or number of components, and constraints on pattern and electrical component settings during printed circuit board design can be relaxed.

Embodiment Hereinafter, one embodiment of the present invention will be described based on the accompanying drawings. In FIG. 1, reference numeral 5 denotes a box-shaped case made of molded resin, and button holes 5a through which button portions 6a formed integrally with the rubber sheet 6 pass are provided in the case 5 according to the number of keys. A boss 5C for fixing the printed circuit board 7 with a screw 8 is provided between the buttonholes 6 from the back side 5b of the case. The rubber sheet 6 has carbon contacts θb corresponding to the number of keys on the back side of the button part e & the base 6.
The boss 6c of the case 6 (7) is provided with a boss hole 6d for relief.The tip of the boss 6C of the case 5 has a stepped portion s e cap, a rubber The printed circuit board 7 is provided so as to face the stepped portion 6f of the boss hole 6d of the sheet 6. The printed circuit board 7 is printed with a carbon contact C that faces the rubber contact θb, and is located at a position that faces the boss 6C of the case 6. A screw hole a is provided in .A rib 6d is integrally provided from the back surface 6b of the case to hold the base 6C of the rubber sheet 6.

With this configuration, as shown in Figs. 2 and 3, if the conventional insulation distance remains the same, the range where the live current parts (carbon contacts 7e, electrical components 9) can be set is shown as... Since the 07 dimension of the present invention can be made smaller than the conventional 0 dimension (φD'<φD), the constraint conditions when designing a printed circuit board are relaxed, which is highly effective in high-density mounting of printed circuit boards. It is something that comes. In addition, since the insulation distance can be secured without the need for the conventional spacer shown in Figure 8, there is a big advantage that the insulation distance against static electricity can be increased, that is, the cost will not increase even if the performance is improved. .

Furthermore, it is easy to think of applying the present invention to the button-equipped structure shown in FIG.

Effects of the Invention According to the present invention, a stepped portion is provided on the periphery of the screw hole of the boss of the case, and a stepped portion opposite to the stepped portion is provided on the rubber sheet, thereby ensuring a large insulation distance from the buttonhole.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of essential parts of an embodiment of the keyboard switch of the present invention, FIG. 2 is a vertical cross-sectional view of the keyboard switch, and FIG. 3 is a plan view showing the setting range of the electrical component mounting pattern of the printed circuit board.
Fig. 4 is an exploded perspective view of the main parts of the conventional example, Fig. 5 is a vertical sectional view thereof, Fig. 6 is a plan view showing the electrical component mounting pattern and pattern setting range of the printed circuit board, and Figs. 7 to 9. FIG. 2 is a vertical cross-sectional view showing another conventional example. 5...Case, 5a...Button hole, 6
b...Back side of case, sc...Boss, 6
d...Reply, 5e...Double part, 6...
...Rubber 7-), 6a... Button part, 6b.
...Carbon m point, 6C...Base, 6
d...Boss hole, 6e...Rib, θf・
...Stepped portion, 7...Printed circuit board, 7a.
...Screw hole, 7b...Notch groove, 7C.
...Carbon contact, yd...Connection sun, 7e...Pattern, 8...Screw, 9
······Electrical component. Name of agent: Patent attorney Toshio Nakao and one other person) (
Ko

Claims (1)

[Claims] In a keyboard switch consisting of a case integrally provided with a boss for fixing a printed circuit board with screws and a rubber sheet provided with conductive rubber, there is at least one step at the tip of the periphery of the screw hole of the boss. A keyboard switch consisting of a case provided with a rubber sheet and a rubber sheet provided with a stepped portion in a boss hole opposite to the stepped portion.