JPH10282183A - Leak-testing apparatus for electric tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a leak-testing apparatus for electric tools which can quickly and easily inspect a shortcircuit of a power source line of a cord of an electric tool and an earth line and a disconnection of the earth line and surely check the presence/absence and danger of a leak of the electric tool. SOLUTION: An earth electrode 21 of a plug receiver (electric outlet 3) to which an insertion plug is inserted or removed is connected to an earth terminal 24 of an insulating resistance meter 4. Edge receivers 22, 23 of the plug receiver are connected to an output terminal 25 of the insulating resistance meter 4. Moreover, a conduction detection instrument (lamp 5) and a battery 10 are connected in series between a probe 6 to which an earth metallic part of an electric tool is butted and the earth electrode 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a test device for checking the presence / absence or danger of leakage of a hand-held or portable power tool such as an electric drill, an electric screwdriver and a sander.

[0002]

2. Description of the Related Art In general, in order to prevent an electric shock of an operator using the power tool, a three-core power cord including a power line and a ground wire in addition to two power lines is generally used. The power supply is widely used, in which the ground wire is connected to a casing or a frame of a power tool, and a plug connected to the cord is inserted into an outlet with a ground electrode to supply power.

However, even in this type of power tool, the power supply line comes into contact with the casing or the like to short-circuit with the ground line,
If the ground wire is broken, an electric shock accident cannot be prevented. Therefore, for example, it is necessary to periodically test for a short circuit or a broken wire. For this reason, conventionally, using an insulation resistance meter (Mega), the insulation resistance between each of the two blades serving as the supply electrode and the ground electrode pin at the insertion plug portion is checked to check for a short circuit in the power supply line. The insulation resistance between the power tool and the metal part such as the casing is checked to determine whether the ground wire is broken.

However, for this purpose, it is necessary to operate the insulation resistance meter while making the two contacts connected to the insulation resistance meter come into contact with the respective blades, the ground electrode pins, the casing, and the like. If the contact is incomplete, short-circuits and disconnections may be overlooked, leading to an electrical leakage accident, which is extremely undesirable in terms of safety.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, and it is possible to quickly and easily check a short-circuit between a power supply wire and a ground wire of a power tool and a disconnection of a ground wire. An object of the present invention is to provide a power tool leakage test device that can reliably check for the presence or danger of leakage of a power tool.

[0006]

According to a first aspect of the present invention, there is provided an earth leakage test apparatus for a power tool, wherein a ground electrode of a plug receiver having a ground electrode into which an insertion plug is inserted / removed is connected to a ground terminal of an insulation resistance meter. And the blade receiver of the plug receiver is connected to the output terminal of the insulation resistance meter, and a conduction detecting tool is provided between the contact contacting the ground metal part of the power tool and the ground electrode. And a battery are connected in series.

In the present invention, the ground metal portion of the power tool is a frame or a casing of the power tool to which the ground wire of the power tool cord is connected, and a metal member (for example, a metal member that is in an electrically conductive state by contact with the frame or the casing). Drill chuck).

[0008] As the energization detector in the present invention, various detectors that indicate energization or non-energization by light or sound, such as a light bulb or a light emitting element that emits light or emits light when energized, a buzzer that emits sound when energized, and the like are used. be able to.

According to the first aspect of the present invention, if the operation switch is connected in parallel to the battery and the energization detector connected in series (claim 2), the operation of closing the switch causes the battery to run out and the battery to run out. It is preferable because it is possible to check whether the energization detection tool has run out, so that it is convenient and it is possible to more reliably check for the presence or danger of electric leakage of the power tool.

In the present invention, as the plug receiver into which the insertion plug is inserted / removed, a connector type connected to a cord may be used. However, an outlet is used as the plug receiver, and the outlet, the insulation resistance meter, and the conduction detection (Claim 3), or a configuration in which the outlet, the insulation resistance meter, the conduction detector, the contact, and the operation switch are mounted on a common panel (claim 3). According to item 4), the insertion of the insertion plug into the plug receptacle (outlet) is easy, and the entire apparatus is compactly integrated and easy to handle.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the figure, reference numeral 1 denotes an earth leakage test device, in which components described below are attached to a metal case 2;
Wiring between components is performed in the case 2. The case 2 is formed by attaching a panel 2b to a box 2a, and a panel 2b on the upper surface is provided with an outlet 3 with a grounding pole, which is a plug receptacle with a grounding pole, an insulation resistance meter 4, and a conduction detector. A certain lamp 5, a contact 6, and a push button switch 7 as an operation switch are mounted. The contact 6 has conductivity for contacting a ground metal part of the power tool.
In this example, a small screw is used by being fastened to the panel 2b with a nut.

A battery holder 11 for accommodating a battery 10 is mounted on the bottom 8 of the box 2a, and a push button for pushing a push button type energizing switch 4a of the insulation resistance meter 4 is provided on the side wall 9 of the box. 12 is attached. This push button 1
2, a rod 14 having a pressing element 13 fixed to the tip is fixed to a button 15, and a compression spring 17 is provided between the button 15 and a guide plate 16 fixed to the side wall 9 to guide the rod 14.
And the button 15 is urged toward the outside of the side wall portion 9, but any other type may be used as long as the power switch 4 a can be pressed.

The components are connected by wiring as shown in FIG. That is, the ground electrode 21 of the outlet 3 is connected to the ground terminal 24 of the insulation resistance meter 4, the blade receivers 22 and 23 of the outlet 3 are connected to the output terminal 25 of the insulation resistance meter 4, and the contact 6 is connected to the ground. Between the pole 21 (or the ground side terminal 24) and the lamp 5
And the battery 10 are connected in series, and the lamp 5 and the battery 10 are connected in series.
, A push button switch 7 is connected in parallel.

Next, a method of using the apparatus having the above-described configuration will be described mainly with reference to FIG. 4 in a case where a leakage test of an electric drill 30 is performed as an example of a power tool. Electric drill 3
Reference numeral 0 denotes a drill shaft 33 attached to a rotating shaft 32 protruding from a casing 31. A plug 35 is attached to a tip of a cord 34 composed of a three-core cord.
37 is connected to the motor in the casing 31 via two power lines in the cord 34, and the ground pin 38 is connected to the cord 3
Connected to the casing 31 via the ground wire in 4 (ground)
Have been.

At the time of the earth leakage test, the plug 35 of the cord 34 generally wound around the outer periphery of the casing 31 is
Plug into outlet 3 of earth leakage tester 1 and push button 12
When the insulation resistance meter 4 is operated by pressing (see FIG. 2), a high voltage is applied between the grounding electrode pin 38 and the blades 36 and 37, and a code is determined based on the presence or absence of the deflection of the needle 4b of the insulation resistance meter 4. The presence or absence of short-circuit between the ground line and the power supply line can be checked.

Next, while the insertion plug 35 is still inserted into the outlet 3, the handle or handle of the electric drill 30 is gripped as shown by a chain line 39 in FIG. The chuck 33 is brought into contact with the contact 6. If the ground wire of the cord 34 is broken (including the detachment of the ground wire and the grounding portion of the casing 31), the lamp 5 does not turn on, and if there is no break, the lamp 5 turns on. Can be determined.

In addition to the above-mentioned leakage test, to check whether the lamp 5 has run out and the battery 10 has run out of battery (insufficient voltage), it is sufficient to press the push button switch 7 and check the lighting status of the lamp 5. When the lamp is not lit (or when the amount of light is insufficient), it is possible to detect that the lamp has run out or the battery has run out (or the battery capacity has dropped), and replace the lamp 5 or the battery 10 to prepare for a reliable leakage test.

The present invention is not limited to the above example. For example, the box 2a of the case 2 may be a leg-shaped one, and the power switch 4a of the insulation resistance meter 4 can be directly pressed by hand. At this time, the push button 12 may be omitted, and the specific configuration and arrangement of each component may be other than those described above. In the above example, the branch line 4 connected to the two blade receivers 22 and 23 of the outlet 3 as shown in FIG.
1 and 42 are connected to one common line 40 and connected to the output terminal 25 of the insulation resistance meter 4, and a changeover switch is interposed between the branch lines 41 and 42 and the common line 40. The changeover switch may be operated to individually check for a short circuit between each of the two power supply lines of the cord 34 and the ground line.

[0019]

As described above, according to the first to fourth aspects of the present invention, the insertion plug of the cord of the electric tool is inserted into the plug receiver to operate the insulation resistance meter and the grounding metal part of the electric tool. By making contact with the contact, short-circuiting of the power and ground wires of the power tool and disconnection of the ground wire (including disconnection of the grounding part) in the power tool can be inspected quickly and easily. Danger can be reliably checked to prevent an electric shock accident.

In addition to the above effects, according to the second aspect of the present invention, it is possible to check the running out of the battery and the power supply detecting tool by closing the operation switch, which is convenient and more reliably. Can be checked for the presence or risk of electrical leakage.

In addition to the above effects, according to the third and fourth aspects of the present invention, the insertion plug can be easily inserted into and removed from the plug receptacle (outlet), and the entire apparatus can be compactly integrated and easily handled. The effect is obtained.

[Brief description of the drawings]

FIG. 1 is a plan view of an earth leakage test device showing an example of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an internal wiring diagram of the earth leakage test device of FIG. 1;

FIG. 4 is a perspective view showing a usage state of the earth leakage test device of FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electric leakage test device, 2b ... Panel, 3 ... Outlet (plug receiver), 4 ... Insulation resistance meter, 5 ... Lamp (electricity detection tool), 6 ... Contact, 7 ... Pushbutton switch (operation switch), 10 ... Battery, 21: ground electrode, 22: blade holder, 23
... Blade holder, 24 ... Ground side terminal, 25 ... Output side terminal, 3
0: Electric drill, 33: Drill chuck, 34: Cord, 35: Insertion plug.

Claims (4)

[Claims] An earth resistance of a plug receiver having a ground electrode into which an insertion plug is inserted / removed is connected to a ground terminal of an insulation resistance meter, and a blade receiver of the plug receiver is connected to an output terminal of the insulation resistance meter. And an electric-current detecting device and a battery are connected in series between the grounding electrode and a contact contacted with a grounded metal part of the power tool. 2. An electric leakage test apparatus for a power tool according to claim 1, wherein an operation switch is connected in parallel to said conduction detecting tool and said battery connected in series. 3. The plug receiver comprises an outlet,
The power tool leakage test apparatus according to claim 1, wherein the outlet, the insulation resistance meter, the conduction detector, and the contact are mounted on a common panel. 4. The plug receptacle comprises an outlet,
3. The power tool leakage test apparatus according to claim 2, wherein the outlet, the insulation resistance meter, the conduction detector, the contact, and the operation switch are mounted on a common panel.