DE2736135A1 - ARC WELDING DEVICE WITH SHIELD GAS - Google Patents

Description

-A-

Applicant: International Business Machines

Corporation, Armonk, 17th Y. 1O5O4 heb-pi

Arc welding device with shielding gas

The invention relates to an arc welding device using a continuous arc under a protective gas atmosphere for the automatic welding of non-contiguous pig points. This type of welding, ie electric arc welding under a protective gas atmosphere, is known. This is often referred to as the continuous welding process and is generally used to produce an uninterrupted weld seam. The limitation to this type of welding is due to the fact that the noise level, that is, the noise produced by the pinhole frequency used to ignite the arc in this type of welding, is produced in making discontinuous welds , occurs practically continuously and thus generates a noise that is similar to that caused by the US / ¹ ! applicable law, the Operational Safety and Health Act (OSIUv), exceeds the permissible hoard.

As the Facluuann knows, ΟΠΙΙΛ is the national authority that lays down regulations on noise levels in industrial plants and factories. In general, the leveling is such that the noise level must be below the level at which hearing damage occurs. In a recently issued order by OSHA, the noise level was set to a maximum of equal to or less than 85 decibels (e.g. <_ 85 dba); if the noise level exceeds this standard, employees working in the vicinity of this noise source must either wear hearing protection or the noise source must be housed within a soundproof chamber.

Whenever a l'olfram arc welding in a protective gas atmosphere for the welding of connected V'erk-BO 976 O28 _{R ()} q R 1 q / Π Β Γ. '■

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pieces are used, then the noise generated by the welding device is within the limits prescribed by OSHA, but if this method is used to weld discontinuous shapes of work pieces, then the noise level generated by the high-frequency ignition current exceeds the maximum limits set by USIIA. In order to comply with OSHA regulations, either a soundproof seal must be used during manufacture; or the workers working in the vicinity of the swelling device must be provided with hearing protection. Both solutions contribute significantly to the costs and thus also increase the costs of the product. Dan has to L'oLge that this type of welding process is not used with non-contiguous welds.

To solve the problems of noise generation in arc welding A better understanding of the protective gas atmosphere will be a brief summary of how the Woifrair-L works Arcades under protective atmosphere, in the following referred to as TIG welding for short. A TIG welding device generally contains two separate and distinct mutually distinguishable circuits, namely the ignition circuit operated with high frequency and a l / echsel- or DC circuit. The high-frequency ignition circuit should ignite the arc used for welding. When the arc once ignited, the welding device switches automatically and runs mLt direct current or alternating current, depending on the system.

The person skilled in the art is familiar with the fact that the ignition circuit operated with high frequency is the actual noise generator. In fact, the level of noise generated by the radio frequency circuit is beyond the acceptable limits specified by OSHA. Normally, however, this circuit is only in operation for a short time, ie to ignite the arc, and the human ear therefore does not perceive this noise. So DO 976 O28 8Π9Β19'05Β ^!

if the regulation given by OSHA is not violated, Once the arc has ignited, the arc will persist if a smooth weld is made will. The arc l) LeiL) t obtained and is by the direct current flowing in the welding device or alternating current. As already mentioned, the DC circuit or the AC circuit an inside the noise level lying within the tolerance limits.

However, if a non-contiguous form of a; t / erkr; tilckes or is to be welded on interrupted surfaces, then the LI »SuhweißvorrIchtung always works in the ignition praise and that creates noise. Lists other words when interrupted Surface Geschve Lf'.t v / Lrd, the high-frequency currentcL'ü ignites U; zvrar the arc, however, before the operation of the Schwe 1 Ii vc> r instigates the experience with (J Le Ich strom oder AC current is switched on, the arc extinguishes. Therefore In dUiScni case, the vision device must always be at start-up affected and creates a legally permissible Noise.

Abc: lu; n from the iScliv.ierigkeLts with the noise tv / ick Lung is the level: Lßiiaht that is generated by the Iichv / Ichtungsvorr Ichtung when it is only operated via the yoke frequency current circuit , went "; Satisfied and leads to cracks or ruptures faster than if the welding is caused by the welding device in uninterrupted direct current or axial flow. This is due to the fact that when the welding device in the direct current oiler is operating, a current of electrons from the welding electrode is generated for a sufficiently long period; flows after the workpieces to be welded, so that a homogeneous connection is established. However, if ilLe welding device only works with the high frequency circuit, then you get an intermittent or

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interrupted electron stream, so that because of a crystallization a less than satisfactory weld joint is produced.

Summary of the invention

The present invention provides the prior art the difficulties resulting from the technology by a novel Device and a method for operating this device overcome, the noise level of the welding device below the upper limit prescribed by OSHA remain.

In particular, the workpiece to be welded is in this case in an adjustment device pushed onto a mandrel. The mandrel is held electrically at the ground potential. Line Clamping device with an electrical ground plane is attached attached to the workpiece. An arc variator with a protective gas atmosphere with an adjustable electrode is then arc-spaced from those to be welded Parts brought into position. By switching on the system, the parts to be welded together are related to brought the welding electrode into position. Then a The arc is ignited and a first electrical circuit is established between the electrode and the parts to be welded built up. As soon as the part is moved away from the vicinity of the electrode, a second one becomes electrical immediately conductive circuit established between the electrode and the ground plane. This has the effect of being a continuous Arc is generated because there is always an electrically conductive circuit between the welding electrode and earth is. However, this keeps the noise level within acceptable limits. In another embodiment According to the invention, only one electrical grounding device is provided, which connects the workpiece and the ground potential to one another

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The invention is now based on exemplary embodiments described in detail in conjunction with the accompanying drawings.

In the drawings shows:

1 is a perspective view of a workpiece,

made according to the teachings of the present invention,

Fig. 4 shows a mandrel and a clamping device for a

Connection of the workpiece to be produced according to FIG. 1 with electrical ground potential,

Fig. 2 is a schematic, partially perspective

Representation or a block diagram of a welding device according to the invention and

Fig. 3 is a partial cross-sectional view through the to

welded workpiece for a better understanding of the invention.

Description of the preferred embodiments

The present invention provides a device with a clamping device, with the help of which a continuous Welding process for welding discontinuous or interrupted shapes of a workpiece can be used without the undesired effects occurring, which always used to occur when this welding process for welding interrupted workpiece shapes according to the state of the art was used. Although the

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Invention for welding any, non-contiguous Workpiece shapes can be used, so the invention is intended in connection with the welding of contact lugs of an Itotorankeru. However, this is not intended should be understood as a limitation of the invention, since the invention can always be used in any case, if not coherent square shapes should be welded together.

The workpiece

Fig. 1 shows a perspective view of a tubular armature 10, whose conductor tracks 12 and 14 according to the invention with one another are to be welded. Each end section consists of a number of contact lugs. For example, the End section 12, the contact lugs 1, 2, 3, 4 ... η. In In the same way, the end section 14 has contact lugs A, B, C, ... N. Each contact tab is from the neighboring contact tab separated by a gap 16 and 18, respectively. A more detailed description of this anchor 1O can be found in German patent application P 21 2O 923.4 of the applicant. The method according to the invention can also be used for welding of flat anchor packages, as for the tubular anchor.

As will be explained in detail, v / ird for welding the contact lug 1 or 2 with the contact lug A or B creates an arc and directs it from the welding electrode onto the selected contact lug. If those Contact lug is welded, the armature 10 is rotated further by one of the distances 16 and 18 and then with respect to the Welding electrode brought into working position. Because the arc is not maintained between the electrode and the gap the arc extinguishes by itself.

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As soon as another contact tab is brought into position with respect to the welding electrode, the arc is started again ignited. This constant re-ignition of what was used for welding Arc makes this process for the welding of discontinuous or interrupted workpiece shapes unacceptable.

Anchors of the type shown in Fig. 1 are made from two printed circuit cards, each of which by coating a support layer, for example made of glass fiber reinforced plastic, is made with a copper foil. The conductor pattern required for the anchor is then produced by chemical etching of the copper foil. The carrier will in the end sections 12 and 14 away from the conductor tracks, where the contact lugs to be welded to one another are created. The cards are then placed on top of one another in such a way that the surface made of glass fiber reinforced plastic the inner diameter forms a tubular anchor, while the fiberglass-reinforced surface of the external circuit card isolates the cards from one another. the Conductor tracks are arranged with respect to one another in such a way that an armature winding is formed after welding the Luden will. After appropriate alignment, the cards are glued around a mandrel with the prescribed diameter, and the contact parts have been welded together to form an anchor. A detailed description of the manufacturing process for the tubular anchor can be found in the applicant's German patent application P 21 4 2 473.7, while the method of manufacturing another type of flat anchor is disclosed in U.S. Patent 3,312,046 dated April 4, 1967 is.

The welding device

Fig. 2 shows purely schematically, partly in perspective, partly

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as a block diagram of a welding system for welding the contact lugs of the armature shown in FIG. 1. the The welding system contains the actual clamping device and the welding device 22. The welding device 22 is a tungsten arc welding device with a protective gas atmosphere of known type, which is not described here in detail shall be. Suffice it to say that the welding device contains a high-frequency circuit that is used to ignite the welding arc and an alternating current or Contains DC circuit that maintains the arc after ignition. There are also switching devices provided, which automatically switch from the high-frequency circuit to the direct current or alternating current circuit during operation, when the arc used for welding is ignited. The welding device 22 includes a welding electrode 24, which is at a suitable distance to maintain an arc from the one to be welded Contact tab is arranged.

The clamping device 20 is operatively connected to the welding device and serves to bring the workpiece for welding in the vicinity of the welding electrodes. The jig 20 consists of a frame 32 with bearing blocks 34 and 36 connected to this frame. A shaft 38 is connected to the bearing block 36 via a spring-loaded terminal 40, fit this spring-loaded connecting the V ¹ can JeIIe be moved in the direction of arrow 43 38th As will be explained later, the mobility of the shaft 38 allows a mandrel 44, on which the armature is attached for welding, to be inserted into and removed from the jig. A coupling 46 is attached to the free end of the shaft 38. This coupling can accommodate one end of the mandrel 44. The other end of the dome is inserted into a bearing 48 which lies on the bearing block 34.

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To rotate or adjust the respective contact tab of the Armature 10 with respect to the welding electrode 24, the mandrel 44 is driven by a motor 50 which is via a reduction gear 52 and the coupling 48 is connected to the mandrel. Overall, this drive can be of a known type. In the preferred embodiment of the invention, a motor with an average speed of 1200 RPM used. The reduction gear had a gear ratio of 150: 1. This means that the mandrel and the workpiece connected to it can rotate at approximately one speed is driven by 11 rpm. Needed at this speed each end or anchor to weld about 5 seconds. This welding process is much more effective as manual processes, such as pulsed electric arcs or resistance welding, which require around 1 second per contact tab. Of course, the speed and setting of the motor and the reduction gear can be faster or slower to reduce the welding speed decrease or increase.

To weld the contact lugs to the end sections 14 or 12, the armature 10 is placed on the mandrel 44. One Clamping device 54 with a cooling ring and a ground connection is placed around the armature 10. The combination of The clamping device 54, armature 10 and mandrel 44 are connected to the frame of the clamping device 20 at the connections or couplings 48 and 46, respectively. The welding electrode 24 of the welding device 22 is then brought to the correct welding distance from end section 14 for an arc. When the welding device is turned on, a cloud of monatomic gas surrounds the tip of the welding electrode and the contact lugs to be welded. The presence of the gas ensures that the welding point is not exposed to chemical

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see reaction or contaminated elements from the surrounding atmosphere will. The details of the clamp 54 will be described. Suffice it to say that for a ground connection grinds a spring loaded abrasive brush 56 on the slip ring 58. Slip ring 58 is the grounding ring for the jig. The spring-loaded grinding brush 56 is via the connecting line 6O on the welding device grounded. Another spring-loaded grinding brush G2 grinds on the mandrel 44, thereby forming a second conductive one Circuit between the mandrel and earth potential. Either the clamping device 54 or the mandrel 44 is in operation grounded. However, in some applications, only one of the devices, rather than both, is grounded.

In Fig. 3 is a partial sectional view of the mandrel 44 with the Armature 10 and the clamping device 54 are shown. The contact lug Ά at the end portion 14 of the armature 10 is opposite the Welding electrode 24 arranged. As soon as the welding device 22 is switched on, between the welding electrode 24 and contact lug A generates an arc in the direction indicated by arrow 64. The arc stays up until the contact lug A is welded. If now the anchor is rotated by the drive device, and runs past the welding electrode, then for example a gap 18 (Fig. 1) under the welding electrode. It is well known that electrons always flow the path of least resistance. Since this also applies here, a second conductive circuit is established between the electrode and the clamping device 54 or the mandrel 44. This second conductive current path is represented by arrow 66. As soon as the gap 18 has passed the welding electrode 24, the arc runs again between the next contact lug and the welding electrode along the path 64. This is repeated over and over again, i.e. the electrons flow constantly along the path

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the track 64 or 66 until the contact lugs on the armature 10 are welded / edged are. Both the The mandrel 44 and the clamping device 54 are grounded. Of course, the device can also be operated when either the clamp 54 or the mandrel 44 is grounded. It was found, however, that by grounding the clamp and the mandrel, the quality of the weld joint is better than when the weld joint is produced when only the mandrel or clamp is grounded. By creating zv / ei current-carrying paths, the once ignited Arc is continuously maintained, and thus the welding device can be in the AC circuit or in the DC circuit operated without the undesirable annoying noise generated by the high frequency circuit will.

Figures 4A and 4B show a perspective view of the dome 44 together with the clamping device 54. FIG. 4A shows a perspective view of the rear side of the clamping device 54, while FIG. 413 is a perspective view of the dome 44 next to the clamping device 54 shows. The mandrel 44 includes a central section 60 and two end sections 70 and 72. The end sections 70 and 72 are shaped to fit into clutches 46 and 48 of the jig. The middle section 68 of the dome 44 is practically cylindrical. The shape is dug so that the armature 10 exactly on the Dorn fits. Of course, the mandrel can be produced in a different shape than in FIGS. 4A and 4B. the The shape of the dome depends on the shape of the workpiece to be welded, and a change in the shape of the dome still falls under the scope of the invention. As already explained, the mandrel 44 carries the workpiece to be machined and also forms a conductive circuit to ground. For this purpose slip rings 74 and 76 are at the ends of the

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Central section 68 of the dome 44 is provided. Although different electrically conductive materials for manufacture of the slip rings can be used, in the preferred embodiment of the invention the slip rings are made of Made of copper. If you attach the workpiece on the mandrel so that the sections to be welded together with one of the slip rings (see. Fig. 3) are in connection, and if then the mandrel via the spring-loaded grinding brush 62 (Fig. 2) is grounded, the entire mandrel is grounded whenever necessary. For electrical insulation between the electrically conductive mandrel and the clamping device 20, the bearing blocks 34 and 36 are made of insulating material manufactured.

The clamping device 54 consists of three separate but identical sections 76, 78 and 80, respectively. The clamping device 54 acts as grounding during a welding process if there is no electrically conductive connection between the workpiece and the welding electrode along the path 64 (Fig. 3) consists. In other words, whenever there is a gap 18 or 16 with an arc gap between the welding electrode 24 is opposite, then a second conductive circuit to earth via the clamping device 54 and the welding electrode 24 via the track 66 is established to maintain a continuous arc. In addition to To establish a conductive connection to earth, the clamping device 54 also serves as a cooling ring and thus keeps the temperature of the workpiece within acceptable limits. Everyone Section of the clamping device is constructed in the same way. The three parts 76, 78 and 80 together practically have the same shape of a cylinder. However, this in turn does not represent a restriction of the invention. In general, the shape of the clamping device will be adapted to the shape of the workpiece to be welded. In the preferred embodiment of the invention, the clamping device for welding an im

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essential cylindrical armature to adapt to this cylindrical armature also have a cylindrical shape. If the However, anchor has a different shape, for example as a flat anchor, then the clamping device would practically a must have the appropriate shape.

Each section of clamp 54 consists of two electrical conductive ring portions 82 and 84 each provided at the ends of the longitudinal dimension. Both conducting ring sections are connected to one another via an electrically conductive flat bar. The flat rail 86 is then with the Slip ring 58 connected via conductive connections 88, 90 and 92, respectively. The front view of the connections is shown in Figure 4B while the rear view is seen in Figure 4A is. The clamping device 54 is then assembled with the aid of coupling pieces 94,96. To close the clamping device are turnbuckles 98, 1CXD, 102 and 1O4 on the end sections 80 or 76 attached. The turnbuckles 98 and 100 are in the intended for receiving sections 102 and 104 hooked in and locked. Of course, other turnbuckles can also be used here without deviating from the concept of the invention be used. Using the multi-section clamp 54, each of the sections is identical Sections grounded via the grinding brush 56, which rests on the slip ring 58. So that is the clamping device always earthed and thus represents a second electrical current path between the welding electrode and earth.

Work catfish

In operation, a workpiece such as an anchor 10 (Fig. 1) is placed on a mandrel 44 (Fig. 4). The clamping device 54 is then wrapped around the workpiece and locked at 98, 100, 104 and 102. Then the core is attached to the jig 20 via the couplings 48 and 46 (Fig. 2)

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clamped and connected. The welding electrode 26 of the welding device 22 is then used for welding the contact lugs of the armature (FIGS. 2 and 3) brought to the distance between the light sources. The workpiece is then in the direction of the arrow 110 rotated either forward or backward (Fig. 2). As soon as a contact lug has arrived under the welding electrode 24 is, this contact lug is welded. However, as soon as there is a gap under the welding electrode, the arc will after the clamping device 54 or the mandrel 44 deflected. This process is continued until the workpiece is welded.

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Claims (1)

2/36135 P Λ T E Ii T Λ M S P R Ü C II E Welding position r.ilt a shielding gas light bucket breaking device with a traceable welding electrode and with an adjustable and drivable clamping device for the setting of a work; bad thing about arc abatand from the welding electrode, v / above that Workpiece is connected to ground via a first electrically conductive connection, characterized in that that the workpiece (10) has a second electrically conductive connection (54, 56, 58, 60, 66) according to Ilasse, which is always effective when the first over the to welding part (1, 2, 3 ... η; Λ, R, C ... £ 1) of the workpiece (10) leading electrically conductive? Ground connection (62) is ineffective. Welding system according to Claim 1, characterized in that the workpiece (10) has a motor armature on its Ends (12, 14) lying to be welded, spacings (16, 18) from one another in the circumferential direction, end on v / cis Contact lugs (1, 2, 3 ... η; Λ, P, C ... II). 3. Welding system according to claim 1 and 2, characterized in that the second electrically conductive ground connection from a clamping device (54) by which the workpiece is clamped on the clamping device (2O; 44) is, and a ground connection (56, 58, 60, 66) connected thereto, and that a section the clamping device is arranged at such a distance from the welding electrode that when a Gap (16, 18) of the arc between welding electrode and welding point now between welding electrode and clamping device is retained. no 976 028 8038 13/055 « ORIGrNAL INSPECTED 4. Welding system according to claim 3, characterized in that that the clamping device (54), which also serves to cool the workpiece, the outer shape of the Workpiece is adapted and consists of several similarly structured sections (76, 78, 80), which over Coupling members (94, 96) are connected to one another in an articulated manner are, and that a pair of coupling members is formed by a releasable turnbuckle (98, 1OO, 1O2, 104). 5. Schv.eißanlage according to claim 4, characterized in that that the clamping device (54) has a slip ring (58) on which a spring-loaded grinding brush (56) the Ilasse connection between the clamping device and the inlet line (60) produces. 6. Method for welding a workpiece ηIt interruptions with a continuous arc welding process on a welding system according to claim 1, characterized in that firstly the welding electrode compared to a part of the with interruptions to be welded provided workpiece brought into position that then the arc between the welding electrode and Workpiece ignited and that the once ignited LichtitfKjcm also maintained in the spaces between the four workpieces v / ird. 7. The method according to Ariüwruch 6, characterized in that first a first electrically conductive connection between the welding electrode and the with interruptions provided workpiece is manufactured for a period of time while the workpiece is being welded, and that then a second electrically conductive connection BO 976 Ο28 ß 0 <ΠΜ <? / 0 5 5 <· established and the arc as long as the second electrical connection is maintained when the workpiece is not being welded. 8. The method according to claim 6 and 7, characterized in that in each case as an electrically conductive connection a ground connection is established. BO 976 028 8 0 9 R 1 9/0 5 S S