JPH0470116B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an arc welding machine that allows an operator to remotely adjust welding conditions such as welding voltage, welding current, feeding speed of consumable electrode wire, or welding speed.

When performing arc welding, it is often necessary to change welding conditions during welding due to changes in welding posture, changes in the shape of the workpiece, etc. Furthermore, in shipyards, ironworks, and the like where large objects to be welded are handled, the installation location of the welding power source and the actual work location are often far apart. In such a case,
It is very inconvenient and inefficient to go to the welding power source and switch the welding conditions every time the conditions are changed. Therefore, prior to welding, a combination of multiple expected welding conditions is preset for the welding power source, and the operator can manually select and carry out the appropriate combination of these preset conditions as necessary. You are required to do so.

Conventionally, devices with this kind of function include a rotary switch in the operator's hand, which can be switched as necessary to select a variable resistor, etc. on the welding power source connected to the rotary switch. Or, the torch switch for welding start command provided on the welding torch can also be used to switch the conditions, count the length of the torch switch's closing time and the number of opening/closing operations, and use the results to determine the welding conditions. Methods that perform switching have been proposed. However, although the former of these conventional methods has the advantage that the type of condition selected by the operator can be read from the position of the rotary switch, a multi-core cable is used to guide the signal from the rotary switch to the welding power source. This not only increases the number of cables and increases the rate of disconnection accidents, but also significantly impedes workability in semi-automatic welding where the welding torch is directly operated by the operator. In the latter case, the number of times the torch switch is pressed does not increase the number of cables, but it is necessary to close the torch switch in order to distinguish between the operation of the torch switch to change the welding conditions and the operation of the torch switch to start welding. Welding is determined to start only when the time has continued for a certain period of time. The closing of the torch switch for switching the welding conditions is completed within this set time, and this opening/closing operation is repeated a predetermined number of times. Therefore, the setting time for this needs to be at least 0.5 seconds or more in order to ensure the reliability of the switching operation.
For this reason, after the torch switch is pressed at the start of welding, welding does not actually start until after this set time has elapsed, and the welding machine's response to the operation of the torch switch is slow, resulting in extremely poor operability. Furthermore, if the torch switch is accidentally released during this time, the welding conditions will be changed unnecessarily against the operator's will. Furthermore, if chattering occurs in the contacts of the torch switch when the contacts are closed, there is a risk that the conditions may be changed depending on the number of openings and closings due to this chattering.

Furthermore, it is impossible for the operator to confirm at all which welding conditions are selected in this way. For this reason, in view of the possibility of malfunction occurring due to the various causes mentioned above, the operator is forced to be extremely nervous when operating the torch switch, and this gives a great sense of anxiety. Furthermore, despite such careful operations, there is a serious drawback in that it is not possible to reliably prevent the occurrence of defective welding due to the fact that target conditions have not been selected.

The present invention eliminates the drawbacks of such conventional devices, and
To provide an arc welding machine that does not require an increase in cables, has good operability, and is equipped with a welding condition remote switching function that allows a worker to constantly check the selected welding conditions at hand.

Fig. 1 is a configuration diagram showing an embodiment of the present invention. In the figure, 1 is a welding torch attached to a hand control box, etc. for starting welding, feeding the electrode wire in small increments, and discharging shielding gas on a trial basis. An opening/closing operation command switch (hereinafter referred to as a switch) 2 for instructing the opening/closing operation of the opening/closing element generates n types of different integer signals of n≧2, for example, voltage signals of different values, according to the operator's selection. At the same time, it is a welding condition switching signal generator (hereinafter referred to as a signal generator) that can visually check the switched welding conditions, and its output is connected in parallel with the contact of switch 1, and the output is connected in parallel with the contact of the switch 1, so that the welding conditions can be visually checked. Directly on or near the hand control box. 3 is a two-core control cable (hereinafter referred to as cable) for guiding the signals from the switch 1 and signal generator 2 to the welding machine main body, for example, to the welding power source side, and is suitable for ordinary torch switches, electrode wire inching switches, etc. Just use the cable from. Reference numeral 4 is a starting circuit that detects the closing of switch 1 and performs opening/closing operations of switching elements such as starting welding, feeding electrode wires, and discharging shielding gas, and generates opening/closing operation command signals due to short-circuiting of input terminals. It operates by. Reference numeral 5 denotes a welding condition switching signal discrimination circuit (hereinafter referred to as discrimination circuit) for discriminating the type of input signal, which discriminates which of the n types the output signal from the signal generator 2 is to discriminate switching. 6 is a welding condition switching signal holding circuit (hereinafter referred to as holding circuit) for holding the judgment result of the judgment circuit 5 by the opening/closing operation signal of the starting circuit 4; When switch 1 is closed at startup, the output terminal of signal generator 2 connected in parallel with it is also short-circuited, so even if the input signal to the discrimination circuit disappears, the previous input state is memorized. It is for. In order to perform these operations smoothly, the discriminating circuit 5 has a holding circuit 6 which is activated by the starting circuit 4 after the input signal becomes zero.
It is suitable that the output signal returns after a short delay until the holding operation is completed. 7 is a welding condition setting circuit which receives the discrimination result of the output signal of the signal generator 2 held by the holding circuit 6 and sets the corresponding welding conditions. This is a circuit that sets the feeding speed of the consumable electrode, etc. In a fully automatic welding machine that performs welding using a cart, it also sets the welding speed. 8 is a welding condition control unit which receives the output signal of the welding condition setting circuit 7 and obtains a predetermined output, and includes a known welding power source, an electrode wire feeding speed control device, and a welding power source whose output is controlled in accordance with an external signal. A truck speed control device, a shield gas discharge control device, etc. can be used. The circuits after the starting circuit 4 and the discrimination circuit 5 may be built into a welding power source or welding machine control device that is far away from the operator's position, or may be installed as a separate control box very close to these. I can do it.

In the embodiment shown in FIG. 1, before starting welding, the operator appropriately selects the signal generator 2 and sets it to output a specific signal among n types of signals. The output of the signal generator 2 passes through a cable 3, and a discrimination circuit 5 discriminates which of the n types it is, and outputs the discrimination result to a welding condition setting circuit 7 via a holding circuit 6. When the switch 1 is pressed to close the circuit at the start of welding, the starting circuit 4 is activated.
The input terminals of are shorted. The starting circuit 4 detects this short circuit of the input terminal and supplies a starting signal to the welding condition control section 8. On the other hand, when the switch 1 is closed, the output of the signal generator 2 connected in parallel to the switch 1 is also short-circuited, but as mentioned above, the discrimination circuit 5 has a slight response delay in response to sudden changes in the input, and the start-up circuit 4, the holding circuit 6 holds the output of the discriminating circuit 5 immediately before the switch 1 closes, so the welding condition setting circuit 7 supplies the previously selected specific welding conditions to the welding condition control section 8. Continuing, welding can be performed under the conditions selected by the signal generator 2 before pressing the switch 1.

The signal generator 2 may have various specific examples as long as it generates a plurality of different signals. Second
A connection diagram of a specific embodiment of the signal generator 2 is shown in FIGS. Each diagram is configured to output n different voltage signals selected by a respective rotary switch. In FIGS. 2 to 5, S is an n-stage rotary switch, and e1 to en are DC power supplies having different voltages, and for example, batteries of 0<e1<e2<...<en are used. Ea or Ec is a DC power supply, r
0 to rn are resistors, resistors r1 to rn
use different values for each. Rb and Rc are resistors, ZD1 to ZDn are constant voltage diodes with different voltages, and a and b are output terminals. In FIGS. 2 and 3, the DC power supply e selected by the rotary switch S is
1 or en or constant voltage diode ZD1 or
ZDn voltage Vz1 to Vzn voltage is output terminal a
Appears between -b. Also, in Figure 4, the DC power supply
The voltage at Eb is divided by resistor Rb and resistors r1 to rn. When the rotary switch S is set to the i-th position, Vi=Eb·Rb/Rb+ri (ri is the resistance value of the i-th resistor ri) is output between output terminals a and b. In Fig. 5, a DC power supply Ec and a resistor Rc are provided separately from the signal generator 2, and a fourth
Contrary to the example in the figure, a voltage of vi=Ec・ri/Rc+ri is output. Therefore, if the resistance values r1 to rn of the resistors r1 to rn in FIGS. 4 and 5 are set stepwise so that r1>r2>...rn, then in the example of FIG. 4, v1< v2
A voltage of <...vn is obtained, and in the example of FIG. 5, a voltage of v1>v2>...vn is obtained.

Fig. 6 shows a starting circuit that receives the output of switch 1 and signal generator 2 between input terminals a and b and commands the start of operation, a discrimination circuit 5 that discriminates the type of signal for switching welding conditions, and starting circuit 4. This shows an embodiment of the holding circuit 6 which holds the discrimination result of the discrimination circuit by the output signal of L0 to L0.
Ln is a level detection circuit that detects the input voltage level and generates a logical output when a voltage within a set range is input, and TR0 or
TRn is a transistor that is made conductive by the output of the level detection circuits L0 to Ln, and the connection circuit of these transistors is determined depending on the output format of the level detection circuits L0 to Ln. CR0 again
CRn are relays, each with a series transistor
The normally closed contacts CR0a to CRna are energized by conduction of TR0 to TRn, respectively, to close them. Also
Ed is a DC power supply. In Figure 6, level detection circuit L0, transistor TR0 and relay
CR0 constitutes the starting circuit 4, and the level detection circuit L
1 to Ln, relays CR1 to CRn, and transistors TR1 to TRn constitute a discrimination circuit 5, and the normally open contacts CR1a to CRna of relays CR1 to CRn and the normally closed contact CR0a of relay CR0 connected in series thereto constitute a holding circuit. 6. FIG. 7 is a connection diagram showing a specific embodiment of the level detection circuits L0 to Ln used in the starting circuit and discrimination circuit of FIG. 6. In the same figure, R51 to R53 are resistors, C51 is a capacitor, and ZD51
and ZD52 is a constant voltage diode, D51 and D52 are diodes, OP51 and OP52 are operational amplifiers, and NAND51 is a NAND gate. Ef is a constant voltage diode for level setting
This is a DC power supply that supplies voltage to ZD51 and ZD52, and a power supply circuit for operating operational amplifiers OP51 and OP52 is not shown. The operation of the level detection circuit shown in FIG. 7 will be explained with reference to the explanatory diagram shown in FIG. In Figure 8, the horizontal axis is the input voltage
Indicates the magnitude of vi, and assumes that the voltage increases toward the right side of the diagram. Further, v1 and v2 indicate changes in the output voltages of the operational amplifiers OP51 and OP52, and although their values are approximately the same, they are slightly different in the figure for ease of understanding. v0 is
The output voltage of the NAND gate NAND51 is shown. Also, vz51 and vz52 are constant voltage diodes ZD5
1 and ZD52 Zener voltage, vz51
indicates the lower limit of the detection voltage level, and vz52 indicates the upper limit, and when the input voltage Vi is vz51<vi<vz52
The output is now available in the time it takes. In Fig. 7, when the input voltage vi is vi<vz51, the output of the operational amplifier OP51 is -vf (vf is the diode D5
1 or forward voltage drop of D52), and vi>
When vz51 is reached, the output of the operational amplifier OP51 rises to the positive saturated output of the operational amplifier OP51.
Also, when the input voltage vi is vi<vz52, the operational amplifier
The output of OP52 becomes a positive saturation voltage, vi>vz5
2, the output of operational amplifier OP52 drops to -vf. Therefore, the NAND circuit NAND51
The input voltages v1 and v2 of will change according to the value of the input voltage vi as shown in FIG. As a result, the output of the NAND circuit NAND51 is as shown in the lower part of FIG.
A 0 volt signal is output only when 1<vi<vz52, and the transistors TR0 to TR0 shown in Figure 6 receive this output in the base circuit.
TRn becomes conductive and the relays connected in series with each are energized. Here, if the constant voltage diodes ZD51 and ZD52 are selected corresponding to each level detector so that the Zener voltages vz51 and vz52 are in the middle of the width of change in the output voltage of the signal generator 2, the signal generator 2 It is possible to reliably determine the type of output signal from the For example, if the output signals of the signal generator 2 are of three types: 3V, 6V, and 9V, the lower limit of the level detection circuit L0 is 0, the upper limit is 1V, the lower limit of the level detection circuit L1 is 2V, the upper limit is 4V, and the level detection circuit L2 is The voltage of the constant voltage diode used in each level setter may be selected so that the lower limit of the level detection circuit L3 is 5V, the upper limit is 7V, the lower limit of the level detection circuit L3 is 8V, and the upper limit is 10V or more. In Fig. 7, capacitor C51 is a delay element installed so that the level detection circuit output changes with a slight delay even when the input signal suddenly changes, and the starting circuit is activated after switch 1 is closed at the start of welding. NAND until the holding circuit 6 completes its operation.
This is to maintain the output of the circuit NAND51.

FIG. 9 is a connection diagram showing a specific embodiment of the welding condition setting circuit 7 for receiving the output of the holding circuit 6 and setting the welding conditions for the welding condition control section 8. For example, a holding circuit 6 holds variable resistors VR1 to VRn that set the welding voltage.
The output of each variable resistor is selected by the normally open contact CR1a or CRna of the output relay, and the output of each variable resistor is received by the OP circuit consisting of the diodes D1 or Dn and output to the welding condition control section 8, for example, as an output voltage setting signal of the welding power source. supply. In addition to the output voltage of the welding power source, the welding conditions covered by the present invention include the output current, the feeding speed of the consumable electrode, and the welding speed, but if it is necessary to switch each of these welding conditions at the same time, It is necessary to provide a plurality of sets of welding condition setting circuits 7, each with a circuit similar to that shown in FIG.

In the above embodiments, the welding conditions are switched by determining the magnitude of the voltage signal, but the present invention is not limited to this. For example, the present invention is not limited to this. The present invention can also be carried out by using an oscillator that discriminates the frequency of the input signal and using a circuit that discriminates the frequency of the input signal as the discrimination circuit. It goes without saying that each circuit can be constructed of a non-contact type circuit using a semiconductor integrated circuit instead of a contact type circuit as shown in the example.

As described above, in the arc welding machine of the present invention, a signal generator that outputs n types of selectable signals is connected in parallel to the switch contacts that command the start of welding, wire feeding, gas discharge, etc. Since the output of this signal generator is led to the discrimination circuit through the two-core control cable of the open/close operation command switch, it is determined which signal corresponds to it and the welding conditions are set, so there is no need to increase the number of control cables. Since there is no cable breakage, there is no increase in cable disconnection accidents, and there is no loss of operability. The selection of welding conditions is based on the adjustment position of a signal generator installed at the operator's hand, such as the notch position of a rotary switch, or the adjustment position that changes with the welding conditions depending on the position or number of times a pushbutton switch or non-contact switch is pressed. Since the welding conditions can be confirmed on the display, it is possible to always set the welding conditions accurately, and the visual confirmation can eliminate the mental burden on the operator. Furthermore, since the selection of conditions can be carried out using a rotary switch, unexpected erroneous settings do not occur due to contact chatter, unlike in the conventional case where the number of openings and closings of a pushbutton switch is counted. Furthermore, since the operation start command and the selection of welding conditions are performed by a completely separate control system, there are many advantages such as no waiting time required to start welding, and the work becomes extremely efficient.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an embodiment of the present invention, Figs. 2 to 5 are connection diagrams each showing an embodiment of a signal generator, and Fig. 6 shows an example of a starting circuit, a discrimination circuit, and a holding circuit. 7 is a connection diagram showing a specific example of a level detection circuit suitable for the embodiment shown in FIG. 6; FIG. 8 is a diagram for explaining the operation of the level detection circuit shown in FIG. 7; FIG. 9 is a connection diagram showing a specific embodiment of the welding condition setting circuit. 1...Opening/closing operation command switch, 2...Welding condition switching signal generator, 4...Starting circuit, 5...Welding condition switching signal discrimination circuit, 6...Welding condition switching signal holding circuit, 7...Welding condition setting Circuit, 8... Reception condition control section, S... n stage rotary switch.

Claims (1)

[Scope of Claims] 1. Arc welding equipped with an opening/closing operation command switch that commands the opening/closing operation of a switching element that starts welding, moves an electrode wire, discharges shielding gas, etc., singly or collectively. In the machine, in addition to the opening/closing operation command switch, a changeover switch is placed near the switch to switch among n types of selectable signals for switching the welding conditions, output the signal, and visually check the switched welding conditions. A two-core control cable in which a verifiable welding condition switching signal generator, a contact point of the opening/closing operation command switch, and an output terminal of the welding condition switching signal generator are connected in parallel at one end; and the other two-core control cable. Detecting that the welding condition switching signal of the welding condition switching signal generator connected to the terminal is input, and determining which of the n types of signals the welding condition switching signal is, and making a switching determination. a welding condition switching signal discrimination circuit that outputs a signal; n sets of welding condition setting circuits selected by the switching discrimination signal; and a welding condition switching signal discrimination circuit connected to the other end of the two-core control cable in parallel with the welding condition switching signal discrimination circuit. a starting circuit that detects an opening/closing operation command signal generated when the opening/closing operation command switch is connected and outputs an opening/closing operation signal; An arc comprising a welding condition switching signal holding circuit that maintains the welding condition switching signal according to the opening/closing operation signal when the opening/closing operation command switch is closed, and a welding condition control section that outputs the welding condition according to the output signal of the welding condition setting circuit. Welding machine.