JPS6335415Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a test rod for measuring resistance.

When a pair of test rods is applied to an object to be measured and its resistance value is measured using a tester or the like, there is a risk of an unexpected accident if the object to be measured is in a live wire state. For this reason, in the past, before each resistance measurement, the function knob of the tester was switched to the voltage range to confirm that no voltage was being applied to the object under test, but this confirmation process was surprisingly easy. It's a hassle.

Therefore, an object of the present invention is to provide a test rod for resistance measurement that can very quickly check the presence or absence of voltage on the object to be measured when measuring the resistance of the object.

Hereinafter, embodiments of this invention will be described in detail with reference to the accompanying drawings. Incidentally, this kind of test rods are usually used as a set of two, and in the embodiment shown in FIG. 1, a test rod 1 according to this invention and a known test rod 1' are used. Examples of combinations are shown.

The test rod 1 according to this invention has a cylindrical grip 2 made of an electrically insulating material such as ebonite, and a conductive probe 3 protrudes from the beak-shaped tip of the grip 2. It is provided so as to be slidable in the direction. The probe 3 has a stopper ring 5 for preventing it from coming off that comes into contact with the inner wall of a chamber 4 formed in the grip 2, and the chamber 4 is connected to the stopper ring 5.
The grip 2 is elastically biased forward by a coil spring 6 disposed therein. Also, inside the grip 2 is a socket-shaped fixed terminal arranged so that when the probe 3 described above is pushed toward the right in FIG. 1 against the coil spring 6, it can come into electrical contact with the rear end. 7 is provided. In this test rod 1, a first lead wire 8 and a second lead wire 9 are connected to the probe 3 and the fixed terminal 7, respectively, through the grip 2.
It is electrically connected to a measuring device 20 such as a tester via these lead wires 8 and 9. The other test rod 1' is well known and will not be described in detail, but this test rod 1' has a cylindrical grip 2' made of electrically insulating material.
and a conductive probe 3' implanted at its tip.
A lead wire 10, one end of which is soldered to the probe 3', is drawn out from the rear end of the grip 2'. Then, the lead wires 8, 9 mentioned above
As shown in FIG. 20. In this case, measuring device 2
0 has three terminals: first and second terminals 21, 22 into which the plugs 11, 12 of the test rod 1 are inserted, and a COM terminal 23 into which the plug 13 of the test rod 1' is inserted, Each of these terminals is connected to a voltage measurement circuit 24, a current measurement circuit 25, a resistance measurement circuit 26, and an alarm circuit 2 via switching means to be described later.
7.
In this embodiment, the switching means comprises a rotary switch. That is, this rotary switch is connected to the first terminal 21,
and is connected to the first fixed contact 28 disposed at a location corresponding to one terminal of the voltage measurement circuit 24 and the second terminal 22, and is connected to one of the current measurement circuit 25 and the resistance measurement circuit 26. a second fixed contact 29 commonly disposed for each of the terminals;
and current measurement circuit 25 or resistance measurement circuit 26
a third fixed contact 30 arranged to connect the alarm circuit 27 to the first terminal 21 when either of the terminals is closed;
4. Consisting of a fourth fixed contact 31 commonly disposed on each of the other terminals of the current measurement circuit 25 and the resistance measurement circuit 26, and a movable contact 32 that cooperates with each of the fixed contacts 28 to 31 described above. has been done. Note that a meter 33 is connected between the fourth fixed contact 31 and the COM terminal 23, and a meter 33 for the alarm circuit 27 is connected between the third fixed contact 30 and the first terminal 21. A protective resistor 34 is connected.

Next, the operation of this invention will be explained. To measure the resistance to be measured Rx, first, the two test rods 1 and 1' are lightly pressed against the resistance to be measured Rx. In this state, the probe 3 is pushed forward by the coil spring 6, so the probe 3 and the fixed terminal 7 are electrically insulated from each other. Therefore, the resistance to be measured Rx will be electrically connected to the first terminal 21 of the measuring instrument 20 via the probe 3 and the first lead wire 8, but in this case, the range switching rotary switch If the voltage measuring circuit 24 is selected by the movable contact 32, it is possible to safely check whether there is a voltage across the resistance to be measured Rx by reading the movement of the meter 33. If it is confirmed through this operation that no voltage is being applied to the resistance to be measured Rx, the movable contact 32 is switched to the resistance measuring circuit 26, and the test rod 1 is then connected to the resistance to be measured.
All you have to do is press it hard against Rx. That is, when the grip 2 is strongly pressed toward the resistance to be measured Rx, the probe 3 is pushed into the grip 2 relatively against the coil spring 6, and comes into electrical contact with the fixed terminal 7 described above. As a result, a circuit including the resistance to be measured Rx, probes 3, 3', lead wires 9, 10, resistance measurement circuit 26, and meter 33 is closed.
The resistance of the resistor to be measured Rx can be measured based on the current value supplied from the resistance measuring circuit 26.
On the other hand, when either the current measuring circuit 25 or the resistance measuring circuit 26 is selected by the movable contact 32, each probe 3,
3' is dangerous, but according to this invention, the movable contact 32 contacts the circuit 25.
or 26 is selected, the third fixed contact 30 and the terminal of the alarm circuit 27 are closed. Therefore, when the resistance to be measured Rx is a live wire, a signal is sent from the resistance to be measured Rx to the alarm circuit 27 via the probe 3, the first lead wire 8, the first terminal 21, the fixed terminal 30, etc. Electric current is supplied, which causes a warning sound, such as a buzzer, to be emitted, allowing the operator to foresee danger. In addition, if the alarm does not sound,
Since it is determined that there is no voltage on the resistance to be measured Rx, either switch the movable contact 32 to the resistance measurement circuit 26, or after confirming that it has been switched, continue to firmly press the probe 3 against the resistance to be measured Rx. If so, the circuit including the resistor to be measured Rx, the probes 3 and 3', the lead wires 9 and 10, the resistance measuring circuit 26 and the meter 33 is closed as described above, and the resistance value of the resistor to be measured Rx is measured. .

As is clear from the above description of the embodiments, according to this invention, the resistance value of the resistance to be measured Rx can be safely measured while checking the live state of the resistance Rx, and is extremely practical.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of this invention.
FIG. 2 is a circuit diagram of the measuring instrument in FIG. 1. In the figure, 1 and 1' are test rods, 3 and 3' are probes, 6 is a coil spring, 7 is a fixed terminal, 8 and 9 are lead wires, and 20 is a measuring device.

Claims (1)

[Scope of utility model registration request] A cylindrical grip made of electrically insulating material, a probe protruding from the tip of the grip so as to be slidable in the axial direction, and the probe elastically biased toward the outside of the grip. a fixed terminal disposed within the grip so as to be able to contact the probe at its rear sliding position when the probe is pushed into the grip against the spring means; a first lead wire, one end of which passes through the grip and is connected to the probe, the other end of which is connected to the voltage detection means; one end of which passes through the grip and is connected to the fixed terminal; A test rod for resistance measurement, comprising a second lead wire connected to a measurement circuit.