DE1941517A1 - Automatic welding machine - Google Patents

Description

, Automatic welding machine

The invention relates to an automatic welding device for arc welding in an inert gas protective atmosphere, preferably for the execution of programmed micro-welds, in particular for the execution of "soldered joints" jacketed thermocouples. With the inventive Welding device, it is possible to carry out spot-shaped micro-welds, such as. B. welds on, one Heating solder joint of a thermocouple with a small diameter, which is protected by a metal jacket; Farther can be used to produce circumferential or ring micro-welds werdeti, for example between a through line of small diameter and a thin metal casing.

"Process for arc welding under an inert gas atmosphere are known. However, the options are

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of the "previously known. Processes in their practical application. limited, namely when very small arc currents are required are how they are used in micro-welding. In addition, the devices commonly used for arc welding only control a few operating parameters provided, d. H. in general will only. the discharge current and · the duration of the gas flow controlled.

Other control or regulation options, such as B. the Control of the discharge time, are in some specially developed for the execution of soldering joints with small thermocouples Welding equipment provided; however, that is work-. program of such devices limited and inadequate if Welding processes of a different kind are to be carried out, for example Perimeter welds through which a through pipe with a permanent element metal sheathing of small diameter is to be welded tightly.

Another disadvantage of the known welding devices can be seen in the high-frequency generators through which the additional insert sheet is generally supplied. These generators have two main disadvantages: on the one hand, they are a source of considerable electromagnetic interference, so that the welder cannot operate in close proximity to any other electronic instrument, and, on the other hand, they are unreliable and require constant maintenance ..

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The object of the invention is therefore to provide a welding device create, with which the aforementioned disadvantages are overcome * and that is designed in such a way that it can easily be soldered a-n thermocouples are produced! tons, it should continue to do so thus be possible to weld the jacket in which these thermocouples are enclosed, and a peripheral weld of these thermocouples on stainless steel wires which are passed through these sheaths. In general, this welding device is intended for sealing welds of through lines of any electrical components be suitable, which of a metal sheathing minor Diameter are enclosed; Such components can be heaters, resistors or the like. be. Should be even more generalized The invention creates a welding / icing device that makes it possible to use small through-lines with metal pipes Diameter of any kind to be worn away.

This task is solved by an automatic welding machine, which according to the invention are generated by a device sum a high-voltage tip for the ignition of the welding arc and a device for mixing the Welding arc thinning voltage and the welding arc supply voltage, wherein the Sehv / ice device is designed so that the ignition voltage is superimposed on the 3 chv; ice voltage and / or after Initiation of the solder arc switched off automatically v / earth * can.

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In particular, this and the below " the following further developments of the invention explained in detail Benefits achieved:

(1) A number of predetermined work programs can be set up perform, which differ from each other preferably by the strength of the arc current, its waveform and the duration of successive Sweat steps can be separated. The most complicated program involves a current spike to ignite or initiate of the welding arc, a constant working current and a gradual or gradual extinguishing current. The welding process can be programmed to automatically evolve within 40 ms up to 8 seconds or it can be controlled manually. The duration of the argon flow can also be changed.

(2) Very small arc currents can be used. That is therefore the pail, because "for- the ignition of the arc one Current peak is used and because it is necessary to ignite the arc High voltage can be included in the program.,. ":

(3) The discharge time program can be preselected and maintained for repeated welding processes, creating a considerable time savings in the execution of conventional welds to be carried out very often, for example at Manufacture of thermocouple Yerbindungen is achieved.

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(4) Thermocouple heating connections can be made repeatedly without the need to make any settings that would otherwise be required to compensate for the different lengths of the thermocouple leads would be.

(5) An introductory visual monitoring of the welding program is provided in so far as the operator controls the various steps of the welding process on a visual monitor can be checked before the discharge is initiated so that any operating errors are avoided.

(6) The arc polarity can be reversed to ground.

(7) The ignition high voltage power can be of the welding fat charge or it can be turned off automatically once the arc is struck.

(8) The high voltage amplitude can be adjusted.

(9) In the device preferably no moving parts need to be provided, such as. B. mechanical timers, breakers or scintillators; In this way, the operational safety of the device is increased and its maintenance is reduced.

(10) Induced electromagnetic noise can be

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through a suitable mixture of ignition and welding voltage avoid.

The mixture of the high voltage arc ignition power with the arc supply voltage is an important feature of the present Invention.

Indeed, it would be impractical to use the output of a high voltage transformer to use to apply the welding performance, because of the excessive dimensions of the equipment required for this; also use a another electrode for generating the ionization discharge would involve considerable complications; closing -I am using a scintillator because of the harmonic Level of its discharge is not recommended. In particular the disadvantages associated with a scintillator are difficult maintenance and a high level of noise in the surrounding space. For the latter reason, the use of such a welding device is not compatible with the use of Instruments for performing electrical measurements in the same laboratory or the like. compatible.

The invention is illustrated below with reference to one of the Pig. T to 6 of the drawing shown in principle ^ particularly preferred Embodiment explained in more detail, but it is not limited to this, but can be under the given

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Guidelines as well as within the scope of the subject matter of the invention and the general inventive concept in a variety of ways realize with success. Show it:

Fig. 1 is a block diagram of a.Schweissgerätes according to the Invention,

Pig. 2a, 2b and 2c a detailed electrical Circuit diagram, although some components are shown in block form because of their conventional, well-known structure are. The circuit diagrams of these three figures together make up the entire circuit diagram of the device, provided the connections 71 to 80 of FIGS. 2b and 2c with the connections 71 'to 80' of Fig. 2a and the connections 90 to 95 of Fig. 2c with the connections 90 'to 95' of Fig. 2a are connected to each other,

Fig. 3 shows an exemplary embodiment of a front panel of the Device,

Fig. 4a a diagram in which the welding current over time is plotted in a program that uses a composite current,

F ₁ Ig. 4b is a diagram in which the welding current is plotted against the second, in a program in which a simple current is applied,

5 shows an exemplary embodiment of a welding bench and

6 shows an illustration of the successive steps a to g of a welding process, with which a heating connection of a vimmantelte hikrothermal element is established.

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The block diagram of the invention shown in Fig.! ' Welding device shows that the device mainly a supply unit 1, which feeds a controlled or regulated diode 2, which in turn over the arc 14 a mixing unit 11 with the required welding power provided.

This welding power calls a control or regulation signal in a sensor 4, that of a timing control unit 7 for the sheet is fed; the latter Unit for its part starts a time control or regulation unit 8 for the flow of inert gas. The unit 8 operates an electromagnetic Valve 9 in the gas supply line 13. The control unit 7 controls a welding program unit 5, which in turn acts on the controlled diode 2 via a control circuit 3 ,, ■

To check the successive steps of the welding process a visual electronic display instrument is provided.

The block 10 connected to the mixing unit 11 represents the

High voltage generator for the generation of the auxiliary ignition arc represent. - ■

Pig. 2a, 2b and 2c illustrate the electrical circuit diagram of the device.

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SAD ORJGfMAL

In order to achieve the best possible clarity of the presentation, are-the conventional components of the electrical®. circuit in the-Mg. 2a, 2b, and 2c are shown in block form, while the novel components in these figures are shown in detail and are surrounded by dashed lines, the latter being the perimeter of the blocks shown in! ig, -1 correspond.

All relays are provided with the reference symbol K supplemented by an index number. The switches, which of the respective, with Relays with the same index number are actuated: are also identified by the reference symbol K and the same index number marked as the relay, but used to differentiate one or more dashes are added to the switches below each other. Furthermore, the contacts of each switch are through a Number denotes to which the letter c is added.

The following applies in detail:

The relay K1 actuates the following switches K1 in block 4 (current measuring sensor unit) Kl "in block 7 (arc timer)

Kl '"with contacts 8c and'1Oc in block 5 (welding program

mation unit it), ■

K1 "" in block 10 (high voltage generator); the relay K3 is actuated the following switches:

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K3 'in block 8 (gas flow timer), K3 "with contacts Hc, 16c and 7c in block 5 (welding programming unit),

K3 ". ¹ in block 10 (high-voltage generator); relay 4 actuates the following switches:

K4 ¹ for the gas flow (Pig. 2c),

K4 "in block 8 (gas flow timer); · · · ■ the relay Ki of block 11 actuates the following switches of the same block: Ki ¹ , Ki", Ki ¹ "and Ki"".

The more detailed explanation of the electrical circuit is with Block 5 '(Fig. 2b) started, this block is called the "welding program unit" '^ denotes, it is used to generate a voltage signal to deliver that after a suitable transformation by block 3 controls diode 2; block 3 is called "SOR (Silicone controlled rectifier) pilot ".

A constant voltage of 10 volts is applied to the ends of the potentiometer R24, which is connected to the supply unit connected elements R25, C15 and Z2 is supplied. These After it has been divided or reduced by the sliding contact on potentiometer R24, voltage 'is via the contact 7c of switch K3 "and switch S3 in its position (b) * applied to the "SOR Pilot" 3.

Lord, the switch S3 is brought to its position (b), then

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the welding current is programmed in such a way that a rectangular Course (Mg. 4b) results because the opening of the contact 7c of K3 ″ from the arc timer 7 depends.

The SCR pilot 5 is designed or arranged so that the Duration of the conductive state when moving the potentiometer sliding contact from A towards B increases.

The connection B of the potentiometer R24 can also be connected to the SCR Pilot 3 are connected via the contact 8c of the switch K1 "'and the contact (a) of the switch S3 together with the associated elements C12 - R21 - R23 - R22 and the contacts 14c-16c of the switch K3 ".

When the Sehalter S3 is moved to position (a), the output voltage from the welding programming unit 5 is not constant, but initially assumes its maximum value. The arc is then initiated or ignited with the current Ii (see FIG. 4a). This current actuates the relay K1 via the "current measuring sensor unit" (Hbck 4), whereby the ^{switch K1 UI is switched} from contact 8c to contact 10c.

As a result, the capacitor C12 is above the adjustable Discharge resistor R2T and resistor R23 with the combined time constant until a voltage value VR is reached, in which the contacts 6c - 7c of the relay K3 "with the Sliding contact of the potentiometer R24 connected diode D1 in

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passes over their conducting state. As a result, the arc is fed with a current of the magnitude I _R (see Figs. 4a, 4b), Ms the time period t_ previously set on the arc timer unit (block 7) has elapsed. At this moment K3 is actuated, so that the switches K3 ″ switch off the supply voltage or power and connect 012 to R22, whereby a discharge takes place with the arbitrarily adjustable time constants' C12. R22. As a result, the arc current takes from I _R to zero (see Fig. 4a).

For a better understanding of the following explanation of the block (Pig. 2a), which is a current sensing unit, be on it pointed out that the circle for the arc current is the following Components connected in series comprises An SCR diode 2, the switch Ki of block 4, the fuse F. and the resistors R20 and R19 j while the following components are connected in parallel in different placesί the capacitor 08, the resistor R18 with the associated switch K4 ", the is actuated by the relay K4.

As far as block 4 is concerned, it is essentially a two-stage direct current solid-state amplifier, whose load is formed by relay K1, whereby protective elements, Polarization elements, test elements and memory logic

ip. ■ '■ =: ■■■■■■■ - ■: \

elements / of the first stage are provided _e

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When the arc current is introduced or ignited, a voltage is applied to the terminals Rt 9, which, when over the divider-R2 gets to the base of the transistor TR1, this transferred into its conductive state. ,

Therefore, if TR1 is conductive and the relay K1 is actuated,-results the following:

(1) The conductive state of TR2 is supported because the voltage of the Zener diode Z1 is sent to the base via the switch Et ' is created by TR2,

(2) the bow timer: is activated via switch E1 "in the block started,

(3) the switch E1 ^M? the welding programming unit (block 5) is operated, as already mentioned), - (4 ·) the switch K1 "" is operated and the supply line to the high-voltage generator (block 10) is always interrupted when the welding programming unit (block 3) associated switch S1 is in its (ä) position.

The Zener diode ZT is also used as protection for TS2. That Element P2 is a reset push button switch.

With the help of the push button P1 the arc stream can be used for the purpose a visual check of the sequence of the welding process can be simulated without igniting the arc

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Depressing this push button releases the voltage at the base of the transistor Tr2 by means of the from the supply unit ". brought the removed voltage to the value of the voltage of the Zener diode; as a result, K1 is actuated again. the visual inspection is done by observing a light indicator, which is inserted at the output of the welding programming unit (block 5.).

With the help of the current measuring sensor unit (block 4) does the arc current start the arc timer (block 7)? which comprises a solid state amplifier whose load is provided by the relay K3; and which comprises a plurality of interchangeable RC groups (01,. '02,. 03, C4, 05, 06; R8, R9, R10, R11, R12, R13) and polarizing elements.

The transistor Tr3, which is normally in its .conducting state (because its base polarity is positive due to the opening of the switch K1 "), goes within a period of time determined by the combination of one of the capacitors C ₁ -Cg and" one of the resistors Rg-R ₁ -, plus R is determined to switch to its non-conductive state.

The SR commutator is intended to be used among the six specified

select one of the programs for the welding time (ts).

The resistors Rg - R ₁ ^ are semi-fixed potentiometers for modifying ts.

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The discharge duration can be controlled by means of an arc remote control be controlled by hand; this remote control comprises a push button which connects the connections TAI and TA2 to each other connected in parallel to switch K1 ". The discharge duration wifd arbitrarily held at its operating value by the operator, which as a result, also during the time ts set by the arc timer unit (which, however, is reduced to an insignificant value of 40 ms can be) happens, whereby the discharge duration is interrupted if necessary according to a preselected program or subsides.

The relay K3 is switched off from the current when the transistor TR3 of block 7 changes to its non-conductive state, thereby triggering the following processes:

(1) The switch. K3 ^U of block 5 is operated in such a way that contacts 14c and 7c are closed while contact 16c opens.

(2) The switch K3 " ¹ " in block 10 interrupts the power supply to the "high-voltage generator" when the commutator S1 is in its position (b).

(3) The switch K3. ¹ of block 8 opens and starts the inert gas flow timer.

The operating mode of the flow timer (block 8) is the same as that of the arc timer. By attitude

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of the resistor H16 can also determine the flow duration can be set after the welding process.

The relay K4 is de-energized when the transistor TR4 of the block 8 passes into its non-conductive state, resulting in the following Processes are triggered:

(1) The switch K4 ¹ interrupts the inert gas flow. Closure of the solenoid valve 9, which is connected to ports B ^ and B ₂ , -

(2) The capacitor C8 is switched by the switch K4 ″ through the Discharge resistor R18.

The high-voltage generator (block 10) comprises' the multivibrator 10a, a variable gain amplifier 10b and a step-up transformer T.

The mixing unit (block 11) comprises a diode D2 “capacitors G9 and 0-10 as well as a relay Ki, which in dei in lig. 2c are switched in the manner shown. . ■

Allowed depending on the position of the switches operated by relay Ki the inserted in the main line diode D2 a termination of the welding current in one or the other Rieh-, tion. With regard to the alternating performance of the transformer mator 7 (block 10), the diode D2 is in series with the capacitor

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gate 010 switched. During the leading half of the Diode D2 will discharge the capacitor G10 to a value Vc, which is equal to the value Vt, so that during the following non-conductive half-cycle across the diode D2 a voltage which is twice of Vt; this voltage conducts the ionizing discharge. Ki is used to reverse the polarity of the welding arc. In both positions of the relay Ki, the high-voltage supply is maintained at the welding electrode, while the workpiece holder is via the capacitor C11 is grounded insofar as the AC components of the transformer T are concerned. ■

The capacitor C9 serves as a short circuit for the high voltage power. :

The R20 rheostat inserted in the arc current line allows compensation for the different electrical Resistances of the parts to be welded. In this way it is possible to carry out a number of welds on different parts Resistance while the parameters of the welding process are maintained unchanged. Hence, for example, a number of thermocouple heating connections are carried out evenly, even if the thermocouples differ in length.

The one shown in Fig. 2c * but omitted in Pig * 1 Block 15 embodies a motor speed controller for

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Control or regulation of the speed of a DC motor, with which the part to be welded is set in rotary motion. Such a motor is mainly used for peripheral welding.

In Fig. 3 is an embodiment of a control faceplate of a device according to the invention * The various control heads, levers, buttons and the like are listed below:

16 - control button for resistor R20 (Fig. 2a) for controlling - the gain of amplifier 10b (block 10);

17 - high voltage amplitude control button;

18 - ammeter for the welding current; 1.9 - high voltage warning lamp;

20 - Control button of the commutator SR of the welding arc timer (Block 7) .;

21 - welding arc time warning lights or lamps;

22 - Controls for the semi-fixed potentiometer (R8 - R15) to set the duration of the welding time (ts according to FIGS. 4a and 4b); ' .

23 - Visual monitoring element for the welding program;

24 - control button for discharge; ■ - '"

25 - Control button for setting the duration of high voltage (ti according to FIG. 4a); ·

26 - Control knob for setting the speed of the

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Motor for performing peripheral welds (block 15);

27 - arch lock (F in Fig. 2c);

28 - Screw for setting the high voltage frequency (Block 10);

29 -Socket H ¹ £ for the workpiece holder ;.

30 - socket 14 "for the arc electrode;

■ 31 - Switch (S2) for reversing the polarity of the welding electrodes (see Fig. 2c);

32 - socket (TA1 and TA2) for the bow remote control;

33 - switch (S1) for the high voltage program;

34- - Screw for adjusting the sensitivity of the current sensor (Bock 4) via the resistor R1;

35 - Operating lever for switches P1 and P2 to connect of the visual monitoring device 6 with the welding program or to separate therefrom; .

36 - EHi- OFF switch for the main supply unit (block

37 - fuse for the main supply unit (block 1);

38 - switch for program selection (S3 of block 5);

39 - Adjustment button (R24 of block 5) for the arc current (IR);

40 - main ON-OFF switch (S4 of block 1);

41 - EllI-OFF switch for the workpiece aging motor;

42 - Connection box for the plug of the adapter holder motor (0M1. And CH2 in Figure 2c).

Fig. 5 illustrates a preferred embodiment a welding device for performing micro-welds according to the present invention.

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The device according to the invention is shown on the left-hand side of FIG. and provided with the reference number 44. On the Bank 43 the following items of equipment are spread out:

A microscope holder 455

a microscope 46; ; . '

an arc electrode with gas nozzle 49 »

a holder 50 for the arc electrode;

a holder 51 which can be set in rotation for circumferential

welds and, \ ■

a torment boring machine 52 on a separate one. Stand.

The following is an example of a welding process Welding a heating connection on a sheathed thermocouple explained. This process is shown schematically in FIG shown. The thermocouple is first clamped in a clamping device, which is carried by a suitable ■ position adjustment block. Then the · thermocouple with the help the fine boring machine 52 axially over a predetermined length drilled out. The "cutting tool" of the drill must be appropriately shaped so that the wires of the thermocouple do not collide the envelope can be pressed or squeezed. The length to the »the thermocouple is drilled open in a corresponding Relation to the outer diameter of the thermocouple as well as the type of connection (earthed or isolated connection).

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The position setting block is then transferred to the base plate of the holder 50 for the arc electrode, and the processing steps illustrated as an example in FIGS. 6c-6d are now carried out by means of a suitable micro-tool. These processing steps are observed through the microscope 46, which is rotated around the stand 45 for this purpose. The arc electrode 49 is fitted into the holder 50 and the thermocouple is centered with respect to this electrode (I ¹ Ig. 6d)

With the help of a previously created data sheet, the Welding process parameters set, d. H":

(1) thermocouple resistor (button 16); "

(2) welding program (switch heTDel 32);

(3) arc duration (ts) (switch 20);

(4) welding polarity (SchalthelDel 31);

(5) unloaded tension (button 39);

(6) High voltage program (SchalthelDel 33);

(7) Argon flow (pressure reducing valve 48 iniig. 5).

When the preselected welding program is executed, the arc electrode is removed and the microscope swiveled around its stand again so that the connection can be checked for errors and ensured that it has a suitable ** distance from the casing and that it is well on the filler material in the room between the connecting lines. and the wrapping ^; ':

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wanden (Pig. 6e) lies. The next step is then performed, "in which the arc electrode 49 in its Holder attached and a new set of. Welding parameters for the sealing welding of the cladding in the area of the heating connection - dung "is selected.

Laughs setting the device to the new welding parameters and before carrying out the appropriate welding process, the operator can ensure that the "intended program" does not contain any major errors achieved by depressing the pushbutton 35 corresponding to the reference symbol PI in FIG. 2a and by visual observation of the monitoring device corresponding to block 6 in FIG. 2b 23, in terms of proper execution. of the smoldering program.

Figs. 6f and 6g schematically show an example from FIG Variety of isolated connections as well as an example the multiplicity of grounded connections; these connections can be produced with the device according to the invention.

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Claims (13)

- Check 25 patents 1 J Automatic welding machine. for arc welding in a protective atmosphere of inert gas, preferably for the execution of programmed micro-welds, in particular for the execution of heated soldering points of jacketed thermal elements, characterized by a device (10) for generating a high-voltage peak for igniting the welding arc and a device (11) for mixing the welding arc ignition voltage and the welding arc supply voltage, the welding device being designed in such a way that the ignition voltage is superimposed on and / or after the welding voltage. Introduction ttaw. Ignition of the welding arc can be switched off automatically. 2. Automatic welding device according to claim!, Characterized by a welding programming unit (5) for the execution of several predetermined welding programs, which differ from each other, among other things, with regard to the mode of change of the arc current, the strength of the arc supply current, the duration of the various welding steps, the duration of the inert gas flow and the duration of the arc ignition voltage differentiate. 3. Automatic welding device according to claim 1 or 2, characterized by a device (6) for the visual 009813/1 Pre-monitoring of the welding program. 4.. Automatic. Welding device according to claim 1, 2 or 3, characterized by means (7) for recording or laying down a predetermined program the duration and / or the "course of the welding current. 5. Automatic welding device according to one of claims 1 to 4, · characterized by a device- (16, R20), by which is both the peak current and the welding current are adjustable in such a way that they meet the electrical intrinsic resistances the different parts to be welded are adjusted. 6. Automatic welding device according to one of claims 1 to 5, characterized in that the device (10) for Generating a high voltage peak current, a multi- 'vibrator (10a) and an amplifier (10b) with variable Gain includes, as well as a transformer (• T -)., '.- whose secondary winding with the device (11) for Mixing the ignition voltage and the Schv / Eisebogen supply voltage connected is. »■ - ■ --_- ■ 7. Automatic welding device according to one of claims 1 to 6, characterized in that the device (11) for Mixing the welding arc ignition saving and the welding , '009813/1133 - 25 arc supply voltage essentially borrowed a diode (D2) .τ. ■ included in the circuit of the welding arc supply current as well as a relay (Ki) with two setting positions, which four Switch "operated, so that the welding arc supply current flows in one direction when the relay is off is in a first setting and in the opposite direction when the relay is in a second setting -is, while in both positions of the relay the high voltage supplied by the high voltage generator (10) is applied; this device (11) furthermore having two Capacitors (09, 010), the first of which is inserted between the two lines, which the Lead arc supply voltage and of which the second in series, with the secondary winding of the transformer (T) and is connected to the diode (D2), the capacitance of the first capacitor (09) also being dimensioned such that that it forms a short circuit for the high voltage. 8. Automatic welding device according to one of claims 2 to 7, characterized in that the device for programming the welding process in relation to the change of the discharge current, the strength of the arc supply current and the piles of successive sweat steps from a programming unit (5) which is controlled by an arc timer (7) and ■ a current sensor (~ 4 -) 'y where the programming 009813/1133 "· '.' ■ '■' - 26 ■ '- means acting on a diode (2) that is in the line . , inserted, .which carries the arc supply voltage, 9. Automatic welding device according to claim 8, characterized in that: the programming unit (5) with a manually operated switch (S3) is provided, v / elcher has two operating positions, one of which is rectangular verlaxif ender welding current is obtained when this switch or the relay in its first operating position is while in the second operating position a changed welding current curve results with a initially decreasing current, then a constant one Stream and finally a sloping stream. TO .. Automatic welding device according to one of claims 8 or 9j characterized in that the arc timer (7) Includes a set of interchangeable RC combinations and a solid-state amplifier that uses a relay (K3) supplied, which in turn on the programming unit (5) the timer (8) for the inert gas flow and the High voltage generator (10) acts. 11. Automatic: welding device according to one of claims ^, · 1 to 10, characterized in that the timer (8) * for the inert gas flow feeds a relay (K4) which has a switch (K4 ¹ ) in the circuit of the controller (48) controls for the gas flow as well as a switch (K4 ") in the arc, ■ supply current circuit. 009813/1133 BATH ORIGINAL 12. Automatic S cliv / e eating device according to one of claims 8 to 11, characterized in that the current measuring sensor (4) is veriiunden with the connections of a V / resistor (R19), v / elcher along one of the two arcuate ^Versor-: supply lines inserted so located that its output as a proportional to the current in this line signal is, which signal is fed to an amplifier, via a variable divider (R1, R2), the adjustment of the excitation insert the probe permitted, furthermore a relay (K1) is fed by the amplifier, which acts on the arc timer (7), the welding programming unit (5) and the power supply for the high-voltage generator (10), provided that the latter has been previously arranged accordingly. 13. Automatic Sehweissgerät according to any one of claims 1 to 12, characterized in that the output signal of the Programming unit (5) separate for feeding the diode (2) in the arch supply line is also used to feed the visual monitoring device (6), which a visual check of the welding operation sequence is allowed, to carry out a push button (P1) is provided for the sensor, by pressing it down a signal is applied to the probe which is the input signal for that probe during the occurrence of an arc is simulated. 009813/1133 BATH ORIGINAL