JP2547162Y2 - Ground wire connection device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground wire connecting device for connecting a ground wire in an airtight case to a case and grounding the case.

[0002]

2. Description of the Related Art Generally, a control device for controlling the opening / closing of a pole switch has an airtight structure because it is mounted in the same manner as a switch. In order to prevent the voltage from being exceeded, a voltage arrester for voltage suppression is grounded inside to protect the built-in equipment. For example, FIG. 7 shows a conventional pole switch control device,
A metal cover 1 and a metal bottom plate 2 for hermetically closing the lower opening of the cover 1 constitute a hermetic case of ground potential,
The lightning arrester 3 is housed in the airtight case, and the ground wire 4 from the lightning arrester 3 is screwed to the ground terminal 5 fixed on the bottom plate 2 as shown in FIG. 7 to connect to the bottom plate 2 and ground.

When a withstand voltage test of the control device is performed, a voltage higher than the voltage suppressed by the arrester 3 is applied to the withstand voltage test. Then, the pressure test is not performed.
Therefore, it is necessary to stop the function of the lightning arrester 3 during the withstand voltage test. Conventionally, as shown in FIG. 9, the device is opened by removing the bottom plate 2 from the cover 1 and connecting the ground wire 4 to the ground terminal 5.
The bottom plate 2 is closed as shown in FIG. 10 in this state, and a voltage test is performed by applying a voltage to the terminals of the connector attached to the bottom plate 2.

[0004]

In the prior art described above, the ground wire 4 of the lightning arrester 3 installed in the airtight case is directly connected to the bottom plate 2 in the case.
At the time of the withstand voltage test, it is necessary to open the case, disconnect the lightning arrester 3 and close the case again to perform the withstand voltage test.
After this withstand voltage test, the above-described reverse operation must be performed again, and there is a problem that the operation becomes complicated and takes time.

The present invention has been made in consideration of such problems of the prior art, and an object of the present invention is to connect a ground wire in an airtight case to a case and ground the case. Another object of the present invention is to provide a ground line connection device which can connect and disconnect a ground line with a simple operation from outside the case.

[0006]

In order to achieve the above object, in the ground wire connection device of the present invention, a conductive annular substrate airtightly penetrated in an airtight case has screw portions at both ends. A conductive shaft is loosely inserted, and a first cylindrical member is fixed between the substrate and a fixed plate integrally fixed to the outer periphery of the shaft outside the case.
An insulating bush is interposed, and a cylindrical second insulating bush is disposed on the outer periphery of the shaft in the case. A nut is screwed, and a ground wire electrically connected to the shaft via the nut is sandwiched between the nut and the second insulating bush. A conductive cap for electrically connecting the shaft and the substrate is screwed.

[0007]

In the construction described above, the ground wire clamped between the second insulating bush and the nut in the airtight case is electrically connected to the shaft via the nut, and this shaft is connected outside the airtight case. By being electrically connected to the substrate by the cap, the ground wire is electrically connected to the airtight case via these nuts, shafts, caps, and the substrate, and is grounded. If the cap is removed from the outside of the case, the electric path between the shaft and the substrate is cut off, so that connection and removal of the ground wire to and from the case can be realized only by attaching and detaching the cap.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described with reference to FIGS. In this embodiment, a lightning arrester 3 is installed in a hermetic case including a cover 1 and a bottom plate 2 having a closed lower surface opening in a control device for a pole switch, as in the conventional example, and a ground wire 4 from the lightning arrester 3 is provided. Is connected to the case, that is, the bottom plate 2 and grounded.

In these drawings, reference numeral 8 denotes a conductive annular substrate, which is fitted in a circular hole provided in the bottom plate 2 and welded to the bottom plate 2 so as to be airtight. Reference numeral 9 denotes a conductive shaft having screw portions 10 and 11 at both upper and lower ends, and a disc-shaped fixing plate 12 integrally fixed to a lower portion, and is loosely inserted into a central hole of the substrate 8 from below. .

Reference numeral 13 denotes a cylindrical first insulating bush provided on the outer periphery of the shaft 9 and interposed between the substrate 8 and the fixing plate 12 to insulate the two from each other. A cylindrical portion 14 is formed integrally, and is fitted into a central hole of the substrate 8 to maintain insulation between the shaft 9 and the substrate 8. Reference numeral 15 denotes a cylindrical second insulating bush disposed on the outer periphery of the shaft 9 in the case, and reference numeral 16 denotes a conductive nut.
After arranging the flat washer 17 and the spring washer 18 in order, the nut 16 is screwed into the screw portion 10 at the upper end of the shaft 9.

The screwing of the nut 16 causes the fixing plate 12
The two insulating bushes 13 and 15 are fastened between them, and the space between the fixing plate 12 and the substrate 8 is airtightly closed by the first insulating bush 13 to maintain the airtightness in the case. Crimp terminal 6 sandwiched between 15 and nut 16
Are electrically connected to the shaft 9 via the both washers 17 and 18 and the nut 16.

Reference numeral 19 denotes a conductive cap having a hexagonal outer shape. The conductive cap 19 has a concave portion 20 opened on the top surface and a screw hole 21 opened on the bottom surface. By housing the first insulating bush 13 and screwing the screw portion 11 at the lower end of the shaft 9 into the screw hole 21, the upper end surface of the nut 19 presses against the lower surface of the substrate 8, and the shaft 9 and the substrate 8 19 are electrically connected. Reference numeral 22 denotes an O-ring that hermetically closes the gap between the upper end surface of the nut 19 and the substrate 8. The fixing plate 12 and the first insulating bush 13 in the recess 20 are hermetically covered with the nut 19.

The conductive portions that come into contact with the outside air, that is, the substrate 8, the shaft 9, the fixing plate 12, and the cap 19 are made of, for example, stainless steel to prevent rust.

In such a configuration, the lightning arrester 3 installed in the case is connected to the bottom plate 2 as shown by an arrow in FIG.
6 can be grounded through the cap 19, the shaft 9, the nut 16, the crimp terminal 6, and the ground wire 4. At the time of the withstand pressure test, as shown in FIG. And the function of the lightning arrester 3 can be stopped, and the bottom plate 8 of the ground wire 4 can be removed simply by attaching and detaching the cap 19 from the outside of the airtight case.
Connection and disconnection to the device will be realized.

In addition, since the space between the substrate 8 and the fixing plate 12 of the shaft 9 is airtightly closed by the first insulating bush 13,
Even when the cap 19 is removed, airtightness in the airtight case can be maintained.

[0016]

[Effects of the Invention] Since the present invention is configured as described above, the following effects can be obtained. The shaft is loosely inserted into the board penetrating the airtight case, insulated by the insulating bush, and this shaft is connected to the board via a cap that is attached to and detached from the shaft outside the case. By simply connecting the shaft to the case, the ground wire inside the case can be connected to or disconnected from the case, eliminating the need to open the case as in the past, simplifying the work of connecting and disconnecting the ground wire. It can be achieved.

[Brief description of the drawings]

FIG. 1 is a cutaway front view of an essential part showing one embodiment of a ground wire connection device of the present invention.

FIG. 2 is a schematic configuration diagram of a control device to which the present invention is applied.

FIG. 3 is a plan view of FIG. 1;

FIG. 4 is a bottom view of FIG. 1;

FIG. 5 is a cut-away front view showing a ground path of the ground line of FIG. 1;

FIG. 6 is a cutaway front view when the cap of FIG. 1 is removed.

FIG. 7 is a schematic configuration diagram of a control device to which a conventional example is applied.

FIG. 8 is a cutaway front view showing a conventional ground line connection device.

FIG. 9 is a schematic configuration diagram of a control device showing a conventional operation of removing a ground line.

FIG. 10 is a schematic configuration diagram showing a control device at the time of a withstand voltage test in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cover 2 Bottom plate 4 Ground wire 8 Substrate 9 Shaft 10, 11 Screw part 12 Fixing plate 13 First insulating bush 15 Second insulating bush 16 Nut 19 Cap

Claims (1)

(57) [Scope of request for utility model registration] A conductive ring-shaped substrate that is hermetically penetrated through an airtight case and is electrically connected to the case; a conductive shaft having screw portions at both ends and being loosely inserted into the substrate; A fixing plate integrally fixed to the outer periphery of the shaft outside the case, a first cylindrical insulating bush interposed between the substrate and the fixing plate on the outer periphery of the shaft, and A conductive second nut which is screwed to the screw portion in the case and press-contacts the two insulating bushes to the substrate between the cylindrical second insulating bush provided on the outer periphery of the shaft and the fixing plate; A ground wire sandwiched between the nut and the second insulating bush and electrically connected to the shaft via the nut; and a peripheral end face screwed into the threaded portion outside the case and connected to the substrate. And electrically connected between the shaft and the substrate. A ground wire connection device comprising: a conductive cap.