JP3111111B2 - Plasma processing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus used for cutting and welding steel materials, and more particularly to a plasma processing apparatus for connecting a plasma torch to a plasma power supply with a relatively long electric cable.

[0002]

2. Description of the Related Art As one type of plasma processing apparatus of this type, for example, a plasma torch of an air plasma cutting machine, as shown in FIG.
5, a plasma power supply 30, a relay box 50, a plasma torch 40, and the like. A plasma start button 41 is provided at the base of the plasma torch 40.

[0003] The plasma power supply 30 contains an electromagnetic valve for supplying air and a high-frequency high-voltage power supply for starting plasma discharge between the electrode and the tip of the torch 40. When the start switch (start switch) 41a is closed, the plasma main power supply and the high-frequency high-voltage power supply are turned on, and the plasma torch 4 is turned on.
A high frequency high voltage is applied between the 0 electrode / chip. The high frequency high voltage triggers a plasma discharge by the plasma mains power supply. The high-frequency high-voltage power supply is automatically turned off after a predetermined time.

A relay box 50 is used when the processing point is several tens of meters away from the plasma power supply 30.
The torch cable 43 connected to the plasma torch 40 via the connector 2 and the intermediate cable 32 connected to the plasma power supply 30 via the connector 31 are connected. The torch cable 43 and the intermediate cable 32 include a voltage line for applying a high-frequency high voltage to the chip, a power line for supplying power from the plasma power supply 30, a working gas supply pipe, and a start signal line connected to the plasma start button 41. It is stored. Also, the relay box 10 has a detachable magnet 6 that is used as a base material terminal that contacts the base material and forms a path through which an arc current flows.
0 is connected via a base material cable 61. Magnet 6
Reference numeral 0 denotes a permanent magnet which has a switching lever (on / off). When the switching lever is turned to the on position, a magnetic path passes through the base material to generate an attraction force, and a closed magnetic circuit is set in the off position. And no longer absorbs the base material. The use of a magnet as a base material terminal as described above has been conventionally known (for example, Japanese Utility Model Laid-Open No. 3-120977 and Japanese Patent Application No. 3-204086 filed earlier by the present applicant).

[0005]

However, as shown in FIG. 12, the magnet 60 is connected to the relay box 5 via a base material cable 61.
When the magnet 60 is attracted to the base material, the torch cable 43 is easily pulled, for example, when the magnet 60 is attracted to the base material, so that the base material cable 61 is easily disconnected, and the disconnection may cause an electric shock accident or the like.

Further, when the plasma start button 41 is pressed even when the magnet 60 is separated from the base material, a high-frequency high voltage is applied to the plasma torch 40 to generate a potential difference between the magnet 60 and the base material. Therefore, the user is exposed to danger such as electric shock.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to prevent electric shock accidents due to disconnection or the like and to ensure work safety.

[0008]

A plasma processing apparatus according to the present invention comprises a plasma power supply (30) having a high-frequency high-voltage power supply for starting plasma and a main power supply for plasma processing; a plasma torch (40); )) To supply working gas to the working gas supply (20);
a), a first cable (32) covering a power line (4a) for supplying power from a main power supply for plasma processing and a working gas supply pipe (5a) and having one end connected to a plasma power supply (30); One end was connected to the plasma torch (40), covering the voltage line (3b) for applying high frequency and high voltage, the power line (4b) for supplying power from the main power supply for plasma processing, and the working gas supply pipe (5b). A second cable (43); connected to the plasma power supply (30);
A third cable (11, 12) housed in the first cable (32);
The third is connected to a cable (11, 12), the the workpiece (70)
Detachable magnets (1, 2) as processing member terminals ; workpiece
Contact surface detecting means (21) for detecting contact / non-contact of magnet (1, 2) with (70); magnet (1, 2) and contact surface detecting means (21)
And a relay member (10) holding the third cable (11, 12) therein and connecting the other end of the first cable (32) and the other end of the second cable (43); When the magnets (1, 2) come into contact with the workpiece (70), high-frequency high voltage, power from the main power supply,
And control means (35, 100 to 105) for supplying the working gas to the plasma torch (40) and stopping it when not in contact. The symbols in parentheses indicate the corresponding elements in the embodiments described later.

[0009]

According to this, the relay member (10) connecting the first cable (32) and the second cable (43) has the magnets (1, 2) used as terminals of the workpiece (70). Then, the third cables (11, 12) for connecting the magnets (1, 2) and the plasma power supply (30) are held therein. That is, the relay member (10) is a magnet
The third cables (11, 12) integrated with (1, 2) are not exposed to the outside. Therefore, the cable required to connect the magnets (1, 2) and the relay member (10), which was conventionally required, is omitted, and the cable is disconnected due to an excessive force such as a tensile force applied to the cable during or after work. As a result, there is no risk of electric shock or the like.

The relay member (10) has contact surface detecting means (21) for detecting whether or not the magnets (1, 2) are in contact with the workpiece (70), and the control means (35, 100). ~ 105) is high frequency high pressure to the plasma torch (40) when the magnets (1,2) come out of contact,
Stop supplying power from the main power supply and working gas.
Thus, for example when working, tension acts on the relay member (10) high-frequency high when the magnet (1, 2) away from the workpiece (70)
Since the pressure is not continuously applied to the plasma torch 40, there is no danger of electric shock or the like caused by generating a potential difference between the magnets (1, 2) and the workpiece (70).

In a preferred embodiment of the present invention, the magnets (1, 2) used as terminals of the workpiece (70) are also used as contact surface detecting means. This eliminates the need for a special component such as a limit switch as the contact surface detecting means, thereby simplifying the cost and reducing the cost.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0013]

【Example】

First Embodiment FIG. 1 shows the appearance of an embodiment of the present invention. The same parts as those of the conventional example shown in FIG. In this embodiment, two magnets 1 and 2 used as base material terminals are incorporated in a relay box 10 for connecting the intermediate cable 32 and the torch cable 43, and the base material cable and the relay box 1 are connected.
The connection of 0 is omitted. The magnets 1 and 2 are detachable permanent magnets (metal magnets) and have a switching lever (on / off). When the switching lever is set to the on position, a magnetic path passes through the base material to generate an attractive force. In addition, a closed magnetic path is formed in the magnet which is turned off, so that the base material is not attracted.

FIG. 2 shows an enlarged cross section of the relay box 10. The intermediate cable 32 and the torch cable 43 are
And a voltage line 3a for applying a high-frequency high voltage to the chip of the plasma torch 40, which is fixed by a frame (material: polycarbonate) 15 and accommodated in the intermediate cable 32.
The power line 4a for supplying power from the plasma power supply 30, the working gas (air) supply pipe 5a, and the start signal line 6a connected to the start switch (start switch) 41a in the plasma start button 41 and the torch cable 43 are also housed. The connected voltage line 3b, power line 4b, working gas supply pipe 5b, and start signal line 6b are connected by a connector 8 and a joint 9, respectively, and are fixed to the internal partition plate 16 of the relay box 10. The plasma start button 41 may be used separately from the plasma torch 40. In this case, the relay box 10 does not have the activation signal lines 6 (6a, 6b).

[0015] Magnets 1 and 2 are fixed to the frame 15. The magnet 1 and the magnet 2 are connected by a base material cable 11 via connection terminals 11a and 11b. The base material cable 12 connected to the magnet 1 via the connection terminal 12a is connected to the plasma power supply 30. Therefore, the plasma power source 30 → the plasma torch 40 → the base material 70 → the magnets 1 and 2
→ Base material cables 11 and 12 → A path through which the arc current flows with the plasma power supply 30 is formed. The direction of this current may be reversed depending on the voltage between the electrode of the plasma torch 40 and the base material 70. Thus, the base material cables 11 and 12
Since the cable is provided inside the relay box 10, the base material cable is not connected to the relay box 10 from the outside.

The internal partition plate 16 has a limit switch 21
Is fixed, and the detection unit protrudes into a hole 15 a provided in a lower portion of the frame 15 to detect contact with the base material 70. Thereby, it is detected whether or not the magnets 1 and 2 used as the base material terminals are in contact with the base material 70. The detection signal is supplied to the plasma power source 3 via the contact surface detection signal line 22.
0, and the activation by the torch switch 41a is controlled. 23 is a protective film of the detecting section.

FIG. 3 shows a schematic configuration of a starting circuit 100 of the air plasma cutting machine shown in FIG. The start / stop control circuit 33 is connected to the start signal line 6 connected to the torch switch 41a and the contact surface detection signal line 22 connected to the limit switch 21. A DC power supply 34 is used as a power supply for the circuit. I have. The start / stop control circuit 33 is a mechanical self-holding circuit, and controls the contact X to "close" when the torch switch 41a is pressed an odd number of times and to "open" when the torch switch 41a is pressed an even number of times. The torch switch 41a is a momentary type switch. The limit switch 21 is “closed” when the limit switch 21 is in contact with the base material 70 (the magnets 1 and 2 are in contact with the base material 70), and is “open” when separated. The diode D ₁ is a diode for backflow prevention.

When the torch switch 41a is pressed when the limit switch 21 is "closed", the start / stop control circuit 3
The contact X of No. 3 is “closed”, and the relay RA is in an excited state. As a result, the contact Ra of the control circuit 35 is closed. The control circuit 35 opens the solenoid valve for supplying the plasma working gas while the contact point Ra is "closed", and outputs a high voltage and a current so as to output the plasma gas and generate arc discharge.
At this time, when the magnets 1 and 2 are separated from the base material 70, the limit switch 21 is opened and the relay RA is de-energized even when the torch switch 41a is pressed. Therefore, the contact Ra of the control circuit 35 is opened, and the control circuit 35 closes the solenoid valve to stop the output of the plasma gas, the voltage, and the current.

In the starting circuit 100, the limit switch 2
The circuit configuration is such that the circuit 1 is "closed" when it is in contact with the base material 70 (the magnets 1 and 2 are in contact with the base material 70) and is "open" when it is away from it. When the limit switch 21 is in contact with the base material 70,
And the starting circuit 10 is configured to be "closed" when separated.
It may be 1. That is, when the torch switch 41a is pressed while the limit switch 21 is "open", the contact X of the start / stop control circuit 33 is "closed". At this time, the relay RB is not excited, the contact Rb is closed, and the relay RA is excited. As a result, the contact Ra of the control circuit 35 becomes "closed", and the control circuit 35 opens the solenoid valve for supplying the plasma working gas while the contact Ra is "closed", and outputs a plasma gas to generate an arc discharge. Output voltage and current. At this time, the magnets 1 and 2
When the distance from 0 is reached, the limit switch 21 becomes "closed", the relay RB becomes excited, and the contact Rb becomes "open". Therefore, even if the torch switch 41a is pressed, the contact point Ra of the control circuit 35 becomes "open" from the non-energized state of the relay RA, and the control circuit 35 closes the solenoid valve to release the plasma gas and the voltage.
Stop the current output.

Note that the start-up circuits 100 and 100 shown in FIGS.
Although the DC power supply 34 is used as the power supply for the power supply 101, a starting circuit having a configuration using an AC power supply as a power supply may be used instead.

Although two magnets 1 and 2 are used in this embodiment, one magnet may be used.

Second Embodiment In the first embodiment, the signal detected by the limit switch 21 is transmitted to the plasma power supply 30 via the contact surface detection signal line 22, but in the second embodiment, FIG. As shown in the figure, the contact surface detection signal line 22 is omitted and the activation signal lines 7a and 7b
The limit switch 21 is interposed between them. The other parts are the same as in the first embodiment, and a description thereof will be omitted.

FIG. 6 shows an outline of the configuration of the starting circuit 102 replacing the starting circuit 100 (FIG. 3) of the first embodiment. Torch switch 41a, limit switch 21 and relay R
A DC power supply 34 is used as a power supply. Limit switch 21 is base material 7
It is "closed" when it is in contact with 0 (the magnets 1 and 2 are in contact with the base material 70) and "open" when it is away from it.

When the torch switch 41a is depressed while the limit switch 21 is "closed", the relay RA is excited. Thereby, the contact Ra of the control circuit 35 is “closed”.
Becomes The control circuit 35 opens the solenoid valve for supplying the plasma working gas while the contact point Ra is "closed", and outputs a high voltage and a current so as to output the plasma gas and generate arc discharge. At this time, when the magnets 1 and 2 are separated from the base material 70, the limit switch 21 is opened and the torch switch 41a
Is pressed, relay RA is de-energized. Therefore,
The contact Ra of the control circuit 35 becomes "open", and the control circuit 35 closes the solenoid valve to stop the output of the plasma gas, the voltage, and the current.

In the starting circuit 102 (FIG. 6), when the limit switch 21 is in contact with the base material 70 (the magnets 1 and 2 are in contact with the base material 70), it is closed and when it is apart, it is open.
However, as shown in FIG. 7, the torch switch 41a and the limit switch 21 are connected in parallel, and when the limit switch 21 is in contact with the base material 70, it becomes "open" and separates. The startup circuit 103 may be configured to be “closed” when in operation. That is, when the torch switch 41a is pressed down to "open" when the limit switch 21 is "open", the relay RA is de-energized.
As a result, the contact Ra of the control circuit 35 becomes "closed", and the control circuit 35 opens the solenoid valve for supplying the plasma working gas while the contact Ra is "closed", and outputs a plasma gas to generate an arc discharge. Output voltage and current. At this time, when the magnets 1 and 2 move away from the base material 70, the limit switch 21 is closed and the relay RA is in an excited state, so that the contact Ra of the control circuit 35 is open even if the torch switch 41a is pressed. . Therefore, the control circuit 35 closes the solenoid valve to stop the output of the plasma gas, the voltage, and the current.

As in the first embodiment, a starting circuit having a configuration in which the DC power supply 34 shown in FIGS. 6 and 7 is replaced with an AC power supply may be used.

Although two magnets 1 and 2 are used in this embodiment, one magnet may be used.

Third Embodiment A third embodiment is a limit switch 21 as a contact surface detector.
Are omitted, and as shown in FIG. 8, the magnets 1 and 2 used as the base material terminals are also used as the contact surface detector. The other parts are the same as in the first embodiment, and a description thereof will be omitted. The detection signal is transmitted to the plasma power supply 30 via the contact surface detection signal line 22 connected to the magnets 1 and 2, and the activation by the torch switch 41a is controlled.

FIG. 9 shows an outline of the configuration of the starting circuit 104 replacing the starting circuit 100 (FIG. 3) of the first embodiment. Start-up/
The start signal line 6 connected to the torch switch 41a and the contact surface detection signal line 22 connected to the magnets 1 and 2 are connected to the stop control circuit 33, and a DC power supply 34 is used as a circuit power supply. . The start / stop control circuit 33 is a mechanical self-holding circuit, and controls the contact X to "close" when the torch switch 41a is pressed an odd number of times and to "open" when the torch switch 41a is pressed an even number of times. The torch switch 41a is a toggle type switch. The magnets 1, 2 and the base material 70 constitute a contact surface detection switch 37. That is, magnet 1,
2 is “closed” when in contact with the base material 70 and “open” when separated. The diode D ₁ is a diode for backflow prevention.

When the torch switch 41a is pressed when the contact surface detection switch 37 is "closed", the start / stop control circuit 3
The contact X of No. 3 is “closed”, and the relay RA is in an excited state. As a result, the contact Ra of the control circuit 35 is closed. The control circuit 35 opens the solenoid valve for supplying the plasma working gas while the contact point Ra is "closed", and outputs a high voltage and a current so as to output the plasma gas and generate arc discharge.
At this time, when the magnets 1 and 2 are separated from the base material 70, the contact surface detection switch 37 is opened and the relay RA is de-energized even when the torch switch 41a is pressed. Therefore, the contact Ra of the control circuit 35 is opened, and the control circuit 35 closes the solenoid valve to stop the output of the plasma gas, the voltage, and the current.

As in the first embodiment, a starting circuit having a configuration in which the DC power supply 34 shown in FIG. 9 is replaced with an AC power supply may be used.

Fourth Embodiment In the third embodiment, the signal detected by the contact surface detection switch 37 is transmitted to the plasma power source 30 via the contact surface detection signal line 22. As shown in FIG. 10, the contact surface detection signal line 22 is omitted and the activation signal lines 7a and 7b are omitted.
The contact surface detection switch 37 is interposed between them. The other parts are the same as in the third embodiment, and a description thereof will be omitted.

FIG. 11 shows a starting circuit 104 according to the third embodiment.
FIG. 9 shows an outline of the configuration of a start-up circuit 105 in place of FIG. The DC power supply 34 is used as a power supply, which is composed of a series circuit including a torch switch 41a, a contact detection switch 37, and a relay RA.

When the torch switch 41a is depressed while the contact surface detection switch 37 is "closed", the relay RA is excited. Thereby, the contact Ra of the control circuit 35 is “closed”.
Becomes The control circuit 35 opens the solenoid valve for supplying the plasma working gas while the contact point Ra is "closed", and outputs a high voltage and a current so as to output the plasma gas and generate arc discharge. At this time, when the magnets 1 and 2 are separated from the base material 70, the contact surface detection switch 37 is opened and the torch switch 41a
Is pressed, relay RA is de-energized. Therefore,
The contact Ra of the control circuit 35 becomes "open", and the control circuit 35 closes the solenoid valve to stop the output of the plasma gas, the voltage, and the current.

A starting circuit having a configuration in which the DC power supply 34 shown in FIG. 11 is replaced with an AC power supply may be used.

[0036]

As described above, according to the present invention, the cable for connecting the magnets (1, 2) and the relay member (10), which has been conventionally required, is omitted, so that this cable is used at the time of work or after the work is completed. There is no fear that the cable will be disconnected due to excessive force such as tensile force applied to the cable, resulting in an electric shock accident or the like.

During operation, when a tensile force acts on the relay member (10) and the magnets (1, 2) are separated from the workpiece (70), a high-frequency high-voltage to the plasma torch (40) and a main power supply Power from
Also, since the supply of the working gas is stopped, there is no danger of electric shock or the like, so that it is safe.

In the preferred embodiment of the present invention, since the magnets (1, 2) used as terminals of the workpiece (70) are also used as the contact surface detecting means, a special part is required as the contact surface detecting means. Simple and inexpensive.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an appearance of a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing the relay box 10 of FIG.

FIG. 3 is an electric circuit diagram showing a schematic configuration of a starting circuit 100 of the air plasma cutting machine shown in FIG.

FIG. 4 is an electric circuit diagram showing a configuration outline of another starting circuit 101 of the first embodiment.

FIG. 5 is an enlarged sectional view showing a relay box 10 according to a second embodiment of the present invention.

FIG. 6 is an electric circuit diagram illustrating an outline of a configuration of a starting circuit 102 according to a second embodiment.

FIG. 7 is an electric circuit diagram showing a configuration outline of another starting circuit 103 according to the second embodiment.

FIG. 8 is an enlarged sectional view showing a relay box 10 according to a third embodiment of the present invention.

FIG. 9 is an electric circuit diagram showing an outline of a configuration of a starting circuit 104 according to a third embodiment.

FIG. 10 is an enlarged sectional view showing a relay box 10 according to a fourth embodiment of the present invention.

FIG. 11 is an electric circuit diagram showing an outline of a configuration of a starting circuit 105 according to a fourth embodiment.

FIG. 12 is a perspective view showing the appearance of a conventional plasma processing device.

[Explanation of symbols]

1, 2: magnet 3a, 3b: voltage line 4a, 4b: power line 5a, 5b: working gas supply pipe 6a, 6b, 7a, 7b: drive signal line 8: connector 9: joint 10: relay box 11, 12: mother Material cable 11a, 11
b, 12a: connection terminal 15: frame 16: internal partition plate 20: air compressor 21: limit switch 22: contact surface detection signal line 23: protective film 25: air unit 30: plasma power supply 31: connector 32: intermediate cable 33 : Start / stop control circuit 34: DC power supply 35: Control circuit 36: AC power supply 37: Contact surface detection switch 40: Plasma torch 41: Plasma start button 41a: Torch switch 42: Connector 43: Torch cable 70: Base material 100 to 105: drive circuit RA, RB: relay

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenji Okuyama 7-6-1, Higashi Narashino, Narashino City, Chiba Prefecture Inside the Equipment Division, Nippon Steel Welding Industry Co., Ltd. (72) Inventor Akio Inamura Higashi, Narashino City, Chiba Prefecture 7-6-1, Narashino Nippon Steel Welding Industry Co., Ltd. Equipment Division (56) References JP-A-63-20173 (JP, A) JP-A-54-162639 (JP, A) JP-A-60-133976 (JP, A) JP-A 3-120977 (JP, U) JP-A 4-21657 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 10/00 B23K 9 / Ten

Claims (3)

(57) [Claims] A plasma power supply device having a high-frequency high-voltage power supply for starting plasma and a main power supply for plasma processing; a plasma torch; a working gas supply device for supplying a working gas to the plasma torch; A power cable for supplying power from the main power source for plasma processing, and a first cable covering one end of the working gas supply pipe and having one end connected to the plasma power supply; a voltage line for applying the high-frequency high voltage; A second cable that covers the power line for supplying power from the main power supply and the working gas supply pipe and has one end connected to the plasma torch; a third cable connected to the plasma power supply device and housed in the first cable Cable; connected to the third cable, and the end of the workpiece to the workpiece
A magnet detachable as a child ; a contact surface detecting means for detecting contact / non-contact of the magnet with the workpiece; a magnet having the magnet and the contact surface detecting means, and holding the third cable therein, A relay member for connecting the other end of the first cable and the other end of the second cable; and
Control means for supplying electric power from a main power supply and a working gas to the plasma torch, and stopping when the plasma torch is out of contact. 2. The plasma processing apparatus according to claim 1, wherein said contact surface detecting means is a limit switch. 3. The plasma processing apparatus according to claim 1, wherein said magnet also serves as said contact surface detecting means.