JP3500918B2 - Plasma cutting torch - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a plasma cutting torch excellent in safety.

[0002]

2. Description of the Related Art The structure of a conventional plasma cutting torch is shown in FIG.
Will be described with reference to.

In FIG. 4, 1 is an electrode made of copper or copper alloy with a cathode material embedded at the tip, 2 is a tip for narrowing a plasma arc, and 3 is a small hole 4 for introducing a working gas into the tip 2. An orifice 5 for electrically insulating the electrode 1 from the chip 2 is a torch body for fixing the shield cup 6 made of an insulator with the electrode 1, and the torch body 5 is a tubular shape made of copper or a copper alloy. Body bracket 5-
1 and a molded portion 5-2 molded with an insulating material having heat resistance. A cooling cable 7 that guides the working gas to the torch tip is connected to the other end of the torch body 5.

[0004]

However, in the conventional plasma cutting torch, the cutting work is continued in a state where the cathode material of the electrode is exhausted, or the cutting speed is too fast so that the cut material is a base material (not shown). In case of abnormal use such as blow-off cutting, the temperature of the torch tip will rise rapidly,
There was a risk of burning the torch body.

An object of the present invention is to solve the above conventional problems.

[0006]

In order to achieve this object, the first means of the present invention is to mold the main body metal fitting with a cylindrical main body metal fitting made of copper or copper alloy and an insulating material having heat resistance. Inside the torch body having the mold part, when the torch body reaches a predetermined temperature, the cutting power source is turned off.
The temperature sensor is set to F. The second means of the present invention is to provide a temperature sensor for detecting an abnormal temperature of the torch body and an alarm element operated by the temperature sensor on the torch body.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION With this configuration, a temperature sensor detects a thermal abnormality of the torch tip portion of the plasma cutting torch, and
It is possible to perform FF, and it has an action of preventing burnout of the torch body.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. (Embodiment 1) In FIG. 1, 1 to 7 are the same as in the conventional example, and therefore the description thereof is omitted. Reference numeral 8a is a temperature sensor that turns off the power supply for cutting when the temperature exceeds a predetermined temperature, and is mounted in the torch body 5. Although the temperature rise value at the time of cutting the tip of the torch body 5 varies depending on the rated current value, in the case of a cutting torch having a rated current of 35 A, the temperature rise value of the main body fitting 5-1 is about 170 deg. When the blow-up cutting which is an abnormal use is performed, the temperature rise value of the main body metal fitting 5-1 reaches the difference of 230 deg.
Therefore, the operating temperature of the temperature sensor 8 is set to 230 ° C. in consideration of the ambient temperature. Then, the temperature sensor 8a detects the rapid temperature rise of the torch tip portion when the cutting work is continued in the state where the cathode material of the electrode is exhausted or the blow-off cutting is performed, and the cutting power source is turned off. The burnout of the torch body 5 can be prevented.

(Embodiment 2) In FIG. 2, 1 to 7 are the same as in the conventional example, and therefore the description thereof is omitted. In the second embodiment, the temperature sensor 8b is provided in the torch body 5 and a light emitting element (alarm element) 9 is provided above the torch body 5 which is not easily affected by the arc light, and the circuit shown in FIG. 3 is configured.
The power source E and the resistor R in FIG. 3 are provided in the power source for cutting. The temperature sensor 8b and the light emitting element 9 turn on the temperature sensor 8b and turn on the light emitting element 9 when a sharp temperature rise occurs at the tip of the torch. Therefore, the operator notifies the thermal abnormality at the tip of the torch, and the operator turns off the torch switch to turn off the torch body 5.
It is intended to prevent the burning of.

[0010]

As described above, according to the first means of the present invention, a body metal fitting made of copper or copper alloy is cut into a torch body molded with a heat resistant insulator when a predetermined abnormal temperature is reached. By providing a temperature sensor for turning off the power, a thermal abnormality at the tip of the torch is detected and the power for cutting is turned off, so that the torch body can be prevented from burning.

According to the second means of the present invention, a temperature sensor which is turned on when a predetermined abnormal temperature is reached in the torch body and an alarm element for issuing an alarm by this temperature sensor are provided, so that the torch tip has a thermal abnormality. Is detected and the alarm element is activated to inform the operator of the heat abnormality of the torch body, so that the operator can turn off the torch switch to prevent the torch body from burning.

[Brief description of drawings]

FIG. 1 is a sectional view of essential parts of a plasma cutting torch according to a first embodiment of the present invention.

FIG. 2 is a sectional view of essential parts of a plasma cutting torch according to the second embodiment.

FIG. 3 is an abnormal temperature alarm circuit diagram of the second embodiment.

FIG. 4 is a sectional view of a main part of a conventional plasma cutting torch.

[Explanation of symbols]

1 electrode 2 chips 3 orifices 4 small holes 5 torch body 5-1 Body bracket 8a, 8b Temperature sensor 9 Light emitting element (alarm element)

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Saito 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP-A-2-92467 (JP, A) 5972 (JP, Y1) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B23K 10/00 504 B23K 10/00 502

Claims (2)

(57) [Claims] 1. A heat-resistant electrode comprising a cathode material embedded at its tip, a tip for concentrating a plasma arc coaxially with the electrode, and a tubular body metal fitting made of copper or a copper alloy for fixing the electrode. A plasma cutting torch having a torch body molded with an insulator, a small hole for introducing a working gas into the tip, and a cylindrical orifice for electrically insulating the electrode and the tip. A plasma cutting torch with a temperature sensor that turns off the power supply for cutting when the temperature inside the body reaches a predetermined temperature. 2. A heat-resistant body comprising an electrode having a cathode material embedded at its tip, a chip for concentrating a plasma arc coaxially with the electrode, and a tubular body metal fitting made of copper or a copper alloy for fixing the electrode. A torch body having a torch body molded with an insulating material, a small hole for introducing a working gas into the tip, and a cylindrical orifice electrically insulating the tip from the electrode. A plasma cutting torch with a temperature sensor that detects an abnormal temperature inside and an alarm element that operates with this temperature sensor provided on the torch body.