JPH036998Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to an operation button suitable for use in a push button device of an electronic device.

(b) Conventional technology When operating the operation button of an electronic device, when the finger approaches the operation button, the electric charge accumulated on the human body is discharged to the conductive parts of the board inside the electronic device, such as the ground line and +B line. However, the impact may cause ICs to malfunction or be destroyed, so-called electrostatic damage. That is, when the operating button is molded with resin, when a charged finger is brought close to the operating button, the air insulation is broken, and discharge occurs to the conductive portion of the circuit board through the gap between the operating button and the front panel. In general, electrostatic discharge damage is related to humidity and distance, and in the case of a potential difference of 25KV, it is said that it is unlikely to occur if the distance is approximately 2.5cm or more. If the distance is long enough, this can be prevented, but as sets become smaller, it is often not possible to maintain a sufficient distance.

As disclosed in Japanese Utility Model Publication No. 55-36889, the gap between the front panel of the operation button can be reduced by a locking part that restricts the position of the pressing part in the protruding direction that protrudes from the opening of the front panel. Although the above-mentioned discharge can be suppressed to some extent, it is not sufficient. Therefore, conventionally, as disclosed in Japanese Utility Model Application Publication No. 59-66825, a metal plate previously connected to ground has been disposed between the operation button and the circuit board to prevent damage to the IC, etc.

(C) Problems to be Solved by the Invention According to the above-mentioned prior art, it is necessary to arrange a conductive member such as a metal plate separately from the operation button, which has the disadvantage that the number of parts and the number of work steps increase.

(d) Means for Solving Problems The present invention is a push button device, which includes a pressing part that projects from an opening in a front panel, an elastic part that biases the pressing part in the projecting direction, and an inner surface of the front panel. a regulating portion disposed on the outer periphery of the pressing portion so as to abut and restrict protrusion of the pressing portion; a first rib disposed around the opening on the inner surface of the front panel; and a second rib disposed on the regulating portion.

(E) Effect Since the present invention is constructed as described above, the first rib and the second rib form an obstacle in the discharge path between the front panel and the operation button, and this prevents the flow of electricity into the front panel. Inflow of static electricity is prevented.

(f) Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of this embodiment, and FIGS. 2 and 3 are perspective views of the apparatus of this embodiment.

The operation button 1 includes a fixed part 2 fixed to the inner surface of the front panel 8, a pressing part 3 operated by the user, and a collar part that regulates the position of the front panel 8 in the front direction when attached to the inner surface of the front panel 8. (Regulating portion) 4, a second rib 5 formed on the outer periphery of the collar portion 4 and protruding in the direction in which the pressing portion 3 projects, a cross-shaped rib 6 extending from the back surface of the pressing portion 3, and the collar portion 4 and the fixed portion. Hinge parts (elastic parts) 7, 7 having elasticity that connect the parts 2 and 2 are integrally molded from an insulating synthetic resin.

On the other hand, on the inner surface of the front panel 8 made of insulating resin, projections 8a, 8a and an opening 9 are arranged, and a first rib 10 is integrally molded around the opening 9.

Note that the heights of the first rib 10 and the second rib 5 are designed to be approximately equal.

The cross-shaped knob 6 is made to face the tactile switch 12 arranged on the printed circuit board 11 installed in the front panel 8, and the pressing part 3 is placed in the opening 9.
After inserting the protrusions 8a, 8a into the through holes 2a, 2a, the operation button 1 is fixed to the inner surface of the front panel 8 by melting the tips of the protrusions 8a, 8a. At this time, as shown in FIG. 4, the first rib 10 is in contact with the collar portion 4, and the second rib 5 is in contact with the front panel 8, and both ribs 10 and 5 are in a fitted state. Therefore, when a charged finger comes into contact with the pressing part 3, the static electricity passes through the gap L1 between the operation button 1 and the opening 9, and then passes through the extremely small gap L2 between the first rib 10 and the collar 4. If it does not pass through the gap L3 formed between the first rib 10 and the second rib 5 and the gap L4 formed between the second rib 5 and the inner surface of the front panel 8, it cannot invade the conductive path in the printed circuit board 11. Can not.

FIGS. 5 and 6 are diagrams showing electrostatic inflow experiments between a push button device using a conventional operation button 3' without first and second ribs 10 and 5, and the device of this embodiment. 12 is a ground pin connected to the ground line of the printed circuit board 11 and has a 1.5KV resistor inserted therein. If both ribs 10 and 5 are not present, the predetermined position P
If you place a power terminal on and gradually increase the voltage,
A discharge is made to the earth pin 15 at 22KV. Next, while maintaining the distance and humidity between the front panel 8 and the printed circuit board 11 under the same conditions, the height of the first rib 10 and the second rib 5 are both 0.5 mm, and the width is also 0.5 mm.
When the same experiment was conducted with the setting set to , the result was that the discharge did not occur until the power supply voltage at point P reached 24KV. That is, it can be said that the electrostatic effect is greater than that of the conventional example.

On the other hand, while the user is pressing the pressing part 3, the shape of the cross-shaped boss 6 that presses the tact switch 12 is the seventh.
As shown in FIG. 8, it is formed by a vertical rib 13 having a tapered portion 13a at an angle θ at its tip, and a horizontal rib 14 whose tip is formed lower than the vertical rib 13. Therefore, when the operation button 1 is pressed, the movable part 12a and the tapered part 1 of the tact switch 12 are first pressed.
The tip surfaces of the movable portions 3a abut in parallel as shown in FIG. 9, and the movable portion 12a is pressed while sliding on the tip surface of the tapered portion 13a without tilting in the vertical direction. on the other hand,
In the unlikely event that the horizontal ribs 14 and the vertical ribs 13
If a pressing force is accidentally applied to the pressing part 3 diagonally from the front so that it is misaligned to the extent that it does not come into contact with a,
Instead of the vertical rib 13, it comes into contact with the movable part 12a and has the function of pressing the movable part 12a and, at the same time, enabling the operation button 1 to return to its original position.

The reason for intentionally creating a step in the height of the vertical rib 13 and the horizontal rib 14 is that the electric discharge machining (in an insulating liquid such as white kerosene The tool and the workpiece are each used as electrodes,
During this process, spark discharge is repeated and the surface of the workpiece is removed minute by minute by the discharge. This method causes unevenness to occur at the intersection of the vertical ribs 13 and horizontal ribs 14, which causes the tact switch 12 to be pressed. This is because it causes a double push in time.

(g) Effects of the invention As described above, according to the invention, by providing a rib on the front panel of the operating section, it is possible to prevent static electricity from entering the front panel, and it is not necessary to separately provide a conductive member for static electricity countermeasures. It has high practical value as it reduces the number of parts and work hours.

[Brief explanation of drawings]

1 to 4 and 6 to 9 relate to an embodiment of the present invention, in which FIG. 1 is a sectional view of the push button device, FIG. 2 is an exploded perspective view of the same, and FIG. 3 is an operation button. A perspective view of
Figure 4 shows how the operation buttons are attached to the front panel, Figure 6 shows the static electricity inflow experiment, Figure 7
The figure is a perspective view of the cross-shaped knob, FIG. 8 is a side view of the same, and FIG. 9 is an explanatory diagram of the operation of the push button device. Also, the fifth
The figure shows a static electricity inflow experiment using a conventional example. 1... Operation button, 3... Pressing part, 4... Flam part (regulating part), 5... Second rib, 7... Hinge part (elastic part), 8... Front panel, 9... Opening part ,
10...First rib.

Claims (1)

[Scope of utility model registration request] A pressing part attached to a front panel and protruding from an opening provided in the front panel; an elastic part that biases the pressing part in a protruding direction; and an elastic part that comes into contact with the inner surface of the front panel to restrict protrusion of the pressing part. In a push button device using an operation button comprising a regulating part disposed around the entire circumference of the pressing part, a first rib is provided around the entire circumference of the opening on the inner surface of the front panel, and a first rib is fitted to the first rib. A push button device characterized in that second ribs are provided at all ends of the regulating portion so as to fit together.