JPH0460745B2 - - 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 for commanding the opening/closing operation of a switching element attached to a welding torch or a hand control box, etc., for starting welding, feeding the electrode wire in increments, trial discharge of shielding gas, etc., either singly or multiple times. 2 is a welding condition switching signal generator (hereinafter referred to as a signal generator) that generates n types of different signals, for example, voltage signals of different values, according to the operator's selection. The output thereof is connected in series with the contacts of the switch 1, and is installed directly or near the operator's hand, for example, a welding torch or 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 denotes a starting circuit for sensing the closing of switch 1 and opening/closing operations of switching elements such as starting welding, feeding electrode wires, and discharging shielding gas. Operate. Reference numeral 5 denotes a welding condition switching signal discrimination circuit (hereinafter referred to as a discrimination circuit) for discriminating the type of input signal, and determines which of the n types the output signal from the signal generator 2 inputted by closing the switch 1 is. 6 is a welding condition setting circuit that receives the discrimination result of the output signal of the signal generator 2 discriminated by the discrimination circuit 5 and sets the welding conditions corresponding to each of the discrimination results. This circuit normally sets the welding voltage, welding current, feeding speed of the consumable electrode, etc. In a fully automatic welding machine that performs welding using a trolley, it also sets the welding speed. 7 is a welding condition setting circuit 6
This is a welding condition control unit that receives an output signal to obtain a predetermined welding output, and is compatible with a known welding power source, electrode wire feeding speed control device, welding cart speed control device, etc. whose output is controlled according to an external signal. , 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. be able to.

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 this signal generator 2 is not transmitted to the discrimination circuit 5 until the switch 1 is pressed, but when the switch 1 is pressed, the discrimination circuit 5 passes through the cable 3 and discriminates which of the n types it is. , outputs the determination result to the welding condition setting circuit 6. On the other hand, when the switch 1 is pressed to close the circuit at the start of welding, the input terminal of the starting circuit 4 is also connected to the signal generating circuit 2.
output is supplied. The starting circuit 4 detects the change in this input signal and supplies the starting signal to the welding condition control section 7, and the welding condition control section 7 controls the welding condition setting circuit 6 according to the signal determined by the discriminating circuit 5. Welding is performed by controlling the output according to the output signal.

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 figure is configured to output n types of different voltage signals selected by respective rotary switches. In FIGS. 2 to 5, S is an n-stage rotary switch, and e1 to en are DC power supplies with different voltages, for example, batteries with 0<e1<e2...<en are used. Ea or Ec is DC power supply, r0
to rn are resistors, and resistors r1 to rn each have a different value. Rb and
Rc is a resistor, 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 source e1 selected by the rotary switch S
or en or constant voltage diode ZD1 or
ZDn voltage Vzl or 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 4 that detects a change in the input signal when the switch 1 is closed and commands the start of operation between the input terminals c and d, and an input signal from the signal generator 2 that is transmitted when the switch 1 is closed. This is a connection diagram showing an embodiment of the discrimination circuit 5 for discriminating the type of , where L0 to Ln are levels that detect the level of the input voltage and produce a logical output when a voltage within the respective set range is input. It is a detection circuit, and TR0 to TRn are transistors that are made conductive by the output of the level detection circuit L0 to Ln.
Connection circuits for these transistors are determined depending on the output format of the level detection circuits L0 to Ln. Further, CR0 to CRn are relays, which are excited by conduction of series transistors TR0 to TRn, respectively. Also, Ed is a DC power supply. In Figure 6, level detection circuit L0, transistor TR
0 and relay CR0 constitute a starting circuit 4, level detection circuits L1 to Ln, relays CR1 to
CRn and transistors TR1 to TRn constitute a discrimination circuit 5.

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 ZD
51 and ZD52 are constant voltage diodes, D51
and D52 are diodes, OP51 and OP5
2 is an operational amplifier, and NAND 51 is a NAND gate. Ef is a current power supply that supplies voltage to constant voltage diodes ZD51 and ZD52 for level setting, 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 FIG. 8, the horizontal axis represents the magnitude of the input voltage vi, and it is assumed 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 When using the circuit shown in Figs. 2 to 4 as the signal generator 2, the switch 1 for commanding the start of welding is used.
The input voltage vi is zero until the switch 1 is opened, and increases to a voltage corresponding to the setting of the rotary switch S at the same time as the switch 1 is closed. Therefore, the level detection circuit L0 used in the start-up circuit 4 is configured to operate when the input voltage rises from zero to a certain value or more, that is, to more than the lowest value of the output voltages of the signal generator 2 selected by the rotary switch S. For example, if the signal generator 2 has three types of output signals: 3V, 6V, and 9V, the lower limit of the level detection circuit L0 should be 2V in consideration of the voltage drop in the middle of the cable, and the upper limit should be 10V. The lower limit of the level detection circuit L1 should be 2V, the upper limit should be 4V,
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 L2 is 5V and the upper limit is 7V, and the lower limit of the level detection circuit L3 is 8V and the upper limit is 10V or more.
Furthermore, when using the embodiment shown in FIG. 5 as the signal generator 2, before the switch 1 is closed, the voltage of the DC power supply Ec is directly supplied as an input signal to the level detection circuit, and when the switch 1 is closed, the voltage of the DC power supply Ec is supplied as an input signal to the level detection circuit. The voltage drops from this voltage Ec to a value divided by one of the resistors r1 to rn, each selected by the rotary switch S, and the resistor Rc. Therefore, in this case, the level detection circuit L0 detects at least the input signal.
It is sufficient to use a device that detects a drop from Ec to near the maximum voltage selected by the rotary switch S, and in this case, the settings of the other level detection circuits L1 to Ln are the same as in the previous case.

FIG. 9 is a connection diagram showing a specific embodiment of the welding condition setting circuit 6 for setting the welding conditions for the welding condition control section 7 in response to the output of the holding circuit 5; , for example, a circuit 5 for determining variable resistors VR1 to VRn for setting 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 an OR circuit consisting of diodes D1 or Dn and output to the welding condition control unit 7, for example, as an output voltage setting signal of a 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 6, each of which has 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 series to the switch contacts that command the start of welding, wire feeding, gas discharge, etc. By closing the opening/closing operation command switch, the output of this signal generator is led to the discrimination circuit via the two-core control cable of the opening/closing operation command switch, and it is determined which signal corresponds to it, and the welding conditions are set. Since there is no need to increase the number of control cables, there is no increase in cable breakage accidents, and there is no loss of operability. The selection of welding conditions can be confirmed by checking the adjustment position of a signal generator installed at the worker's hand, such as the notch position of a rotary switch, so it is possible to always set the welding conditions accurately. This can eliminate the burden on people. 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 occurring when welding is started, 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 is a connection diagram showing an example of a starting circuit and a discrimination circuit. FIG. 7 is a connection diagram showing a specific embodiment of a level detection circuit suitable for the embodiment of FIG. 6;
FIG. 8 is a diagram for explaining the operation of the level detection circuit shown in FIG. 7, and FIG. 9 is a connection diagram showing a specific example 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 setting circuit,
7...Welding condition control unit, 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, there are n types (n
Welding a series circuit of a welding condition switching signal generator that outputs a selectable signal (an integer of ≧2) by switching with a changeover switch, a contact point of the opening/closing operation command switch, and the welding condition switching signal generator. A two-core control cable is connected to a signal input terminal of the machine body, and a welding condition switching signal of the welding condition switching signal generator is inputted to the other end of the two-core control cable when the opening/closing operation command switch is closed. a welding condition switching signal discrimination circuit that detects that the welding condition switching signal is one of the n types of signals, and determines which of the n types of signals the welding condition switching signal is; n sets of welding condition setting circuits; a starting circuit connected in parallel to the other end of the two-core control cable to detect that the opening/closing operation command switch is closed and outputting an opening/closing operation signal; An arc welding machine comprising a welding condition control section that outputs welding conditions according to an output signal of a condition setting circuit.