Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K9/00—Arc welding or cutting
  • B23K9/04—Welding for other purposes than joining, e.g. built-up welding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
  • B23K35/02—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape
  • B23K35/0255—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape for use in welding
  • B23K35/0261—Rods, electrodes, wires
  • B23K35/0277—Rods, electrodes, wires of non-circular cross-section
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K9/00—Arc welding or cutting
  • B23K9/12—Automatic feeding or moving of electrodes or work for spot or seam welding or cutting
  • B23K9/122—Devices for guiding electrodes, e.g. guide tubes
  • B23K9/123—Serving also as contacting devices supplying welding current to an electrode

Definitions

• This invention relates to automatic arc melding and more particularly to an improved contact device for supplying welding current to a continuous, strip-shaped welding electrode.
• Contact devices of this kind are used, for instance, in welding apparatus for coating or cladding a metallic workpiece with a layer of the same or another metal by means ⁇ f strip electrodes having a width/thickness ratio in the range between 300:1 and 10:1.
• a usual strip dimension is 60 x 0.5 mm.
• the electrodes may consist of various steel alloys or nonf ⁇ rrous metals or alloys, according to the desired composition of the layer of metal deposited.
• One or more strip electrodes are fed forward from a reel or reels by means ⁇ f an advancing unit towards the welding arc through the contact device in which the welding current is transmitted to the electrode from one terminal of a source of welding power.
• the other' terminal of the source of welding power is connected to the workpiece on which the electrode metal is to be deposited.
• the invention provides an improved contact device for a continuous, strip-shaped welding electrode comprising a contact member having a contact surface for slidingly engaging one side of the moving electrode strip, and a pressure member arranged slidingly to engage the other side of the electrode strip far providing the contact pressure required between the electrode strip and the contact member.
• said contact surface constitutes a shallow groove arranged to be traversed longitudinally by the electrode strip and that said pressure member is arranged to engage the strip at a zone intermediate edge zones ⁇ f the strip to depress said intermediate zone into the groove and thereby to cause said edge zones to engage the groove under the action of the bending stress caused by the depression of said intermediate zone.
• the term “shallow” should be understood to indicate that the depth of the groove must not be so large as to allow a permanent (plastic) deformation of the strip depressed therein.
• FIG. 1 is a (somewhat schematical) side view of a welding head for a strip electrode.
• Fig. 2 is a vertical section taken along II-II of Fig. 1.
• Fig. 3 is a horizontal section taken along III-III of Fig. 1.
• Fig. 4 is a side view of a contact member forming part of the welding head of Fig. 1.
• Fig. 5 is a side view ⁇ f a modified farm of the contact member.
• Fig. 6 is a vertical section taken along VI-VI ⁇ f Fig. 5.
• Fig. 7 is a view from one end ⁇ f a modified form of the contact device.
• Fig. 8 is a vertical section of a welding head for two strip electrodes.
• Fig. 9 is a horizontal section taken on IX-IX ⁇ f Fig. 8.
• Fig. 10 is an end view of a modified form o f the contact device of Figs. 8 - 9.
• Fig. 11 shows, in transversal section, one form ⁇ f the pressure member ⁇ f the contact device ⁇ f the invention.
• the welding head represented in Figs. 1 to 4 comprises a strip advancing unit and a contact device.
• the advancing unit is shown schematically only as a pair of cylindrical rolls 2, 3 gripping the electrode strip 1 to push the strip through the contact device 4.
• at least one of the rolls 2, 3 has to be driven by a motor through suitable drive mechanism.
• the advancing unit as wall as the contact device are assumed to be supported by a welder frame not shown.
• the contact device 4 is provided with a contact member 5 which may, for instance, consist of copper or a wearresistant copper alloy.
• a screw clamp 6 serves to connect the contact member to a welding current conductor connected to one terminal of a source of welding power the other terminal ⁇ f which is connected to a workpiece.
• the side of the contact member 5 facing the strip 1 is provided with a contact surface having the form ⁇ f a shallow, transversally curved groove 7.
• a pressure member 8 is rigidly attached to the contact member 5 by means of an electrically insulating cross-piece 9 and a pair of screws 10.
• the pressure member 8 consists of a straight bar extending along the centre line of the contact surface.
• the edge of the bar facing the contact surface is rounded with a radius of curvature less than the one of the contact surface and is separated from the contact surface by a space slightly exceeding the thickness of the strip 1.
• the bar 8, or at least its edge portion engaging the strip 1, preferably consists of wear-resistant material. As the bar 8 is electrically insulated from the contact member 5 and the strip 1 and, consequently, substantially no current will flow from the bar 8 to the strip, no electric erosion (spark erosion) of the bar can occur along its line ⁇ f engagement with the strip 1.
• the end of the contact member 5 adjacent to the rolls 2, 3 is bevelled at 11 to provide an inclined surface by which the edge portions of the strip are gradually bent out of the plane shape (to the right in Fig. 2) while the middle portion of the strip is retained by the bar 8 in a position close to the central portion of the groove-shaped contact surface 7.
• the pressure required to be exerted upon the edge zones of the strip at both sides ⁇ f the bar 8 in order to retain the strip in its bent state maintains a firm engegement between said edge zones and the contact surface and this ensures the trouble-free passage of the welding current from the contact member to the strip.
• the ratio .length/ width ⁇ f the groove of the contact member is about 1.6. As a rule, said ratio should not be less than unity.
• the "stick-cut" that is, the length ⁇ f the electrode between the lower edge ⁇ f the contact member and the arc
• this portion of the electrode will retain a transversally curved shape.
• the incre-ased stiffness imparted thereby to the stick-out part of the electrode is useful when the electrode is used for submerged-arc welding, as it improves the ability of the electrode to plow through the lay ⁇ r of welding flux on the workpiece.
• the contact member is provided with a U-shaped groove 12 extending transversely of the contact surface 7, each of the parts of the V extending from the centre of the contact surface 7 to the edge of the contact member 5.
• the groove 12 allows the escape of particles, for instance flux powder grains, which may have been caught between the strip 1 and the contact surface 7. The particles thus entering the groove 12 will slide along the groove and drop out at the edge of the contact member.
• the welding head of Figs. 1 to 4 can also be used for operating two superimposed strip electrodes instead of the single electrode 1 shown.
• the modified contact member 15 shown in Figs. 5 and 6 is provided with a slot 13 extending transversely of the contact surface 14.
• the slot is slightly inclined downwards from its aperture in the contact surface to allow entering particles to slide towards the backside 16 ⁇ f the contact member and drop out.
• the contact member may, if desired, be provided with two or more grooves 12 and slots 13, respectively, arranged behind each other.
• two laterally spaced pressure members 17a, 17b may be provided, as shown in Fig. 7. This arrangement is sometimes useful, for instance when very wide strips are used.
• the welding head o f Figs. 3 - 9 is provided with a wire advancing mechanism with a pair of advancing rolls 20, 21 common to two strip electrodes 18, 19.
• the strips are pushed into a contact device 22 having a contact m ⁇ mb ⁇ r 23 common to both strips and provided' with a groove-shaped contact surface 24, 25 for each ⁇ f the strips.
• Each ⁇ f said contact surfaces cooperates with a b ⁇ r-shaped pressure member 26, 27, respectively, similar to the pressure member 8 ⁇ f Figs. 1 - 3.
• Both of the contact surfaces are provided with a transversal groove 28, 29 similar to the groove 12 of Figs. 1, 2 and 4.
• the contact device of Figs. 8 - 9 does not have to be combined with an advancing mechanism common to both of the strips. It is equally passible to advance the strips by means of individual pairs of advancing rolls which may for instance, be operated at different advancing rates to provide different rates of fusion for two electr ⁇ des having different compositions.
• the modified contact device shown in Fig. 10 has a contact member consisting of two halves 30, 31 separated by a longitudinal gap 32 and connected by a yoke 33. This arrangement allows the strip electrodes to be advanced very close to each other.
• Fig. 11 shows (in section) a pressure member having a wear-resistant edge portion 34 consisting, for instance, of hardened steel or sintered carbide or sintered alumina.
• the contact surface or at least the zones of the same destined to engage the edge zones of the strip, should be curved in order to provide a favourable distribution of the contact pressure.
• a cylindrical surface will be suitable.
• a contact member the contact surface of which forms a segment of a cylinder havin the radius 125 mm operates satisfactorily with an austenitic stainless steel strip of the dimensions 60 x 0.5 mm.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Plasma & Fusion (AREA)
• Arc Welding In General (AREA)
• Manufacture Of Switches (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20340290

Family Applications (1)

Country Status (6)

Cited By (1)

Families Citing this family (1)

Citations (5)

Family Cites Families (3)

• 1980
  • 1980-02-19 SE SE8001299A patent/SE439608B/sv not_active IP Right Cessation
• 1981
  • 1981-02-17 DE DE8181850026T patent/DE3160399D1/de not_active Expired
  • 1981-02-17 AT AT81850026T patent/ATE3699T1/de active
  • 1981-02-17 JP JP56500704A patent/JPS57500095A/ja active Pending
  • 1981-02-17 EP EP81850026A patent/EP0034577B1/de not_active Expired
  • 1981-02-17 WO PCT/SE1981/000043 patent/WO1981002402A1/en unknown

Patent Citations (5)

Non-Patent Citations (1)

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