JPH1041643A - Electronic circuit device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic circuit device which discharges static electricity to an earth before the finger charged with static electricity touches the operation part. SOLUTION: An acrylic cover 2 is provided with a slot 2n and a cut 2k, and the end is locked doubly for slip stoppage with hexagonal nuts 21 after passage of a thumb screw 3 3 into the acrylic cover 2 and a front cover 1, and the thumb screw 3 is made electrically continuous with an earth not shown in the figure through the front cover 1, and the static electricity of the finger is let flow via the thumb screw 3, and then the thumb screw 3 is loosened, and the acrylic cover 2 is shifted and the operation part not shown in the figure is operated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electronic circuit device such as an inverter device.

[0002]

2. Description of the Related Art FIGS. 3 and 4 show a conventional example relating to the present invention. In FIG. 3, reference numeral 11 denotes a front cover of the box of the inverter device, and 11k denotes a window provided on the front cover, which has a structure in which a manual operation unit on a printed wiring board (not shown) is operated when necessary. Since this structure has no function of preventing misunderstanding or mischief, the structure of FIG. 4 is often used.

FIG. 4 shows a front cover 12 in which a window 12k and two holes 12a are machined, an acrylic cover 13 as a display cover in which two holes 13a are machined, and two plastic bushes 14. Have been. Normally, when two plastic bushes 14 are pushed into the respective holes 13a of the acrylic cover 13 and the respective holes 12a of the front cover 12 from the configuration shown in the drawing, the plastic bush 14 attaches the acrylic cover 13 to the front cover 12. Fix it. There is no operation of the operation unit (not shown) without performing this structure. Then, when operation is necessary, one plastic bush 14 is pulled out and the acrylic cover 13 is removed.
Is rotated, or the operation part is operated after the two plastic bushes 14 are pulled out and the acrylic cover 13 is removed.

[0004]

In the example of FIG. 3 described above,
The manual operation parts such as the operation buttons on the printed wiring board are touched by human fingers, so if touched by a high-voltage electrostatic finger, the printed wiring board will be discharged and the electronic components will be destroyed. Sometimes had to be replaced.

In the example shown in FIG. 4, even if the plastic bush is pulled out by a high-voltage electrostatic finger, the acrylic cover is removed from the notch in the front cover.
The seed is an insulator, and the surface of the front cover is also an insulating paint. Therefore, static electricity is not discharged, and a failure may occur due to the same phenomenon as in FIG. An object of the present invention is to provide an electronic circuit device that discharges static electricity to the ground before a finger charged with static electricity touches an operation unit.

[0006]

According to the present invention, there is provided a window provided on a front cover of a box body in which a printed wiring board having an operation unit is housed, a display cover for covering the window, and a display for the display. A hole having a long hole and a notch provided diagonally to the front cover, a screw hole provided in the front cover corresponding to the hole having the long hole and the notch, and the long hole and the notch. It has a structure having a double nut hooked conductive thumb screw inserted into each of the holes.

[0007]

FIG. 2 is a perspective view showing the structure of an embodiment of the present invention. In the figure, 1 is a front cover, 2
Is the acrylic cover for the display cover, 3 is the thumbscrew, 2
1 is a hexagon nut. The front cover 1 is formed with two windows 1k and two screw holes 1a for the thumb screws 3, and
a is electrically connected to a ground (not shown). A long hole 2n is formed at one end of the acrylic cover 2 and a notched hole 2k is formed at a diagonal position at the other end. The major axis direction of the long hole 2n coincides with the direction in which the thumbscrew 3 that enters the notched hole 2k comes off, and the long hole 2n and the notched hole 2k.
k corresponds to the screw holes 1a provided in the front cover 1, respectively. Knob screw 3 has a knurled side surface to increase friction when turned with a finger, and the screw portion is elongated as described later.

FIG. 1 shows an assembled state of FIG.
(a) is a plan view and (b) is a side view. An acrylic cover 2 is fixed to a front cover 1 with a thumbscrew 3. The end of the long screw portion of the thumb screw 3 is locked by the two hexagon nuts 21 to prevent the thumb screw 3 from coming off. If the user tries to operate the operation unit (not shown) and tries to loosen the thumbscrew 3 with a charged finger, the static electricity of the finger is discharged to the ground via the thumbscrew 3 and the front cover 1. And
When the thumbscrew 3 is loosened, the acrylic cover 2 is moved in the long hole direction, and the notched hole 2k is
The acrylic cover 2 is rotated away from the position so that the operation unit can be operated.

[0009]

According to the present invention, the finger always touches the thumbscrew that is electrically connected to the ground before the finger touches the operation section of the printed wiring board. Therefore, when the finger is charged, the static electricity is discharged from the thumbscrew to the ground. Does not flow to the printed wiring board, and does not cause electrostatic breakdown. In addition, since the acrylic cover is shifted and rotated only by loosening it instead of removing the thumbscrew, the structure is such that the acrylic cover is securely grounded every time to prevent forgetting or being lost. Further, the double nut prevents the thumb screw from falling off.

[Brief description of the drawings]

FIG. 1A is a plan view of a structural diagram of an embodiment of the present invention,
(b) is a side view

FIG. 2 is an exploded perspective view of the embodiment of the present invention.

FIG. 3 is a perspective view of a conventional example.

FIG. 4 is another perspective view of a conventional example.

[Explanation of symbols]

 Reference Signs List 1 front cover 1a screw hole 2 acrylic cover 2k notched hole 2n long hole 3 knob screw 11 front cover 14 plastic bush 21 hexagon nut

Claims (1)

[Claims] 1. A window provided on a front cover of a box in which a printed wiring board provided with an operation unit is housed, a display cover covering the window, and a diagonal of the display cover. A hole having a long hole and a notch, a screw hole provided in the front cover corresponding to the hole having the long hole and the notch, and a hole having the long hole and the notch. An electronic circuit device comprising: a double nut hooked conductive thumb screw.