USRE18221E - lincoln - Google Patents

Description

J. LINCOLN- Oct. 6,1931.

ARC WELDING Ma ya -F lv 1w.

2 Sheets-Sheet 1 m z a a m J. F. LINCOLN ARC WELDING Re. 18,221 b'r iginal Filed Jul? 3, 1923 2 Sheets-Sheet 2.

' Oct. 6, 1931.

IN VEN TOR.

A TTORNE Y6 Reissued Oct. 6 1931 UNITED STATES Re. 18,221 T PATENT oFFlcs JAMES I. LINCOLN, OF EAST CLEVELAND, OHIO, ASSIGNOB TO THE LINCOLN ELECTRIC COMPANY, OF CLEVELAND, OHIO, A CORPORATION OFOHIO Anc WELDING Original No. 1,774,023, dated August 26, 1930, Serial No. 649,246, filed July 8 1923. Application form-- issue filed June 16, 1931. Serial No. 544,889.

The present improvements have more particular regard to methods of electric welding and of working metal by electricity in general, wherein an electric arc is struck between the part or parts to be fused and a carbon electrode that is'moved relatively to such parts to be fused and a carbon electrode that is moved relatively to such parts so as to cause the arc to transverse the work. One serious difliculty that has alwas been encountered in such arc welding is t e tendency of the arc to lag or stick as well as to shift irregularl from one point to another on the work.- he resultant weld produced by such are will be correspondingly variable and hence unsatisfactory in character.

As a result of an extended investigation, I believe I have ascertained the major factors which contribute to such behavior of the arc. One of these, and perhaps the strongest is the tendency of the arc to 0 to the hot spot on the work and not leave t at hot spot until the arc is attenuated very much longer than would be the distance to the nearest cold spot. This action is well known and as a result thereof if the welding is one in which the metalis not rendered molten entirely through or at least to a considerabledepth, the are will be rather wild and will tend to drag. In other words, the arc stream will lengthen out back of the are away from the direction in which it is traveling relatively to the work. In addition, however, to the foregoing, there are other ma etic conditions, the importance of which in 51bit behavior of the arc has not heretofore been appreciated.

Onelof these magnetic conditions is that produced b .the incoming current through the work w ere such current flow, as is ordinaril the case, requires to turn at approximately right angle to go into the electrode,- it being understood thatthelatter is necessarily connected withthe negative side and sueh work with the positive side of' the electric current source. Another such magnetic condition is that due to the flux set up in the metal of the work itself by the current thus flowing herethrough to the electrode holder.

'Still another such condition is that due to the flux which is set up in the clamps .em-

various ways in played to retain the work in place where-I have found it to be desirable, for other reasons, that the work should be firmly clamped to a bed or equivalent support. Y

The effect of these various conditions on the are, as well as their interaction, will be herematter more fully described in connection with the description of the various corrective measures which I have devised forneutral- 'izing or controlling the" efiectsproduced.

The general object of the improvements thus made, it ma be-stated, is to control the di'-. rection of lowof the arc: so-as to cause the same to incline in any desired direction from the end of the-electrode, for exam 1e, forwardly or rearwardly or laterally to eit er side, havlng regard to the direction of travel of the electrode relatively to the work. A fur: I

ther object is to obtain a smooth, even action of the are so as to produce a more nearly perfect'weld. f

To the accomplishment of the'fforeg oing and related ends, the inventiomthen, con sists of the steps and means hereinafter-fully described and particularl pointed: out in theclaims, the annexed drawings and the following description setting inf'detail'onc approvedmethod of and mechanism for carrying out the invention, such disclosed means, however, constituting but one of the which the principle of the invention may be used. i In said annexed-drawings v v Fig. 1 is a more or lessdiagrammatic representation ofan arc welding mechanism or apparatus embodying my present improve ments and adapted to operate invaccordance' with my present improved method, such ap-. paratus being shown as applied to the welding of a longitudinally extending seam between the edges of two juxtalposed plates or sheets of metal; Fig. 2 is a p I! view of the same; Fig. 3 is a transverse section thereof, the plane of the section being indicated by the lines 3.-3, Figs. 1 and 2; Fig. 4 isa broken transverse view, similar to that of Fig. 3,

but showing the parts therein appearin on a that a filler strip or'wire .2 may be inserted the-prpfiletion 10 in question the current rim therebetween or such strip may be placed so as simply to rest upon the seam. This element 2 will usually be of the same material, 1. e. iron or steel, as the metal of the sheets, but may if desired contain special alloying constituents or even be of a different metal entirely, so faras the actice of the present invention is concerned Theobject of the 11- lustrated operation, it will be understood, is to melt down such element 2 and interfuse the same with the edges of the sheets 1, 1, so that the result-ant seam 3, as shown at the lefthand end of Figs. 1 and- 2, will be of substantially the same thickness as the sheets and possess a strength and ductility equal to, if not greater than, that possessed by such sheets.

, As shown, the sheets 1 with such filler element 2 inter osed between. their abutting edges are preerab1y supported on a bed or anvil 4 which will preferably be of steel ex cept for a strip 5 of copper which is disposed directly beneath the seam, and thus below the line of the weld, such strip serving a particular and important function as will be present- 1 explained. The welding, as previously incated, is accomplished by means of an electric arc, a carbon electrode 6 being employed, and the weldin circuit, including such carhen, the filler efiament 2 and the bed or anyll 4 or rather the stri 5 which, as aforesaid, forms a part 'thereo The holder 7 forsuch electrode, shown in side elevation in Fig. 1 is of a special design that forms no part. 0% the present invention, such holder being characterized, among other things, by having connections 8 for circulating a cooling 'quid through the body thereof. It will be observed, however, that while the electrode is adjustablysupported the holder-body by means of an adjustable chuck 9, such body is formed at its extreme lower end with a projecting portion 10 through which the electrode passes and wherewith it is in electrical contact so that the current is required to pass only throu h a very short section of the electrode, viz, 5m portion which extends beyonld ough the y from int on bein I of the hol or which is 0 copper or equiva lent conducting material.

For the purpose of clamping the sheets 1, 1 onto the supporting bed or anvil 4, I employ two bars '12, 12, that are laid on the apt to becomeheated,

work, one on each side of the seam or joint to be welded. These bars are of such weight in themselves, or such additional pressure may be applied thereto, as to cause them to retain the edges of the sheets that constitute the work securely in place upon such bed and they will be of metal or equivalent conductive material. Specifically I make the main body of said bars of steel, each bar being provided along-its lower edge with a base 13 in the form of a strip of copper or equivalent metal of relatively high heat as well as electrical conductivity that is integrally united with the steel bar as by welding to such steel portion of such bar 12. The dimensions of the bars 12 in cross-section may vary, but preferably they will height than width, as shown in Fig. 3, so as to laterally enclose the electrode 6 and the are that is formed between the latter and the work when the operation of welding is in rogress. It Will further be noted that the ases 13 of said bars are respectively formed with inwardly extending portions or toes 14 that may be approached closely to either side of-the seam or lineof weld and in such osition overlie the corresponding edges 0 the copper strip 5 in bed 4; also that the upper corners of the juxtaposed edges of said bases 13 are cut away or beveled.

Further note should be made of the fact that due to the construction of these bars, as well as their location in close proximity to the path of travel of the electrode, or rather of the are, any tendency on the' part of such are to wander laterally will be effectually overcome. In other Words,"the material of the bars being of metal and the bases thereof being furthermore of copper, or equivalent high heat conductivit the are once'struck preferentially stays y the pool of molten metal or'crater thereby the electrode is moved along the line of the weld and the arc becomes attenuated, it will more readily follow such line, where the latter is guarded, so to speak, on either side by a bar of the character described. Such-bars, and particularly the even in the proximity of the arc, tothe de ee that the portion of the filler strip just i the adjacent edge portions of sheets'l do. Accordingly, the arc is constrained to move in the desired direction'instead of jumping to one side or the other. The inwardly directed portions 14 of the copper bases 13. furthermore serve to confine the overflow of molten metal resulting from the interfusion of the filler stri or wire 2 with the abutting edges of the p ate 1 and so assist in forming a smooth seam with straight edges throughout its length.

The upper face of said'strip 5,115 best formed in the work, and as bases thereof, are notorwa'rd of the arc and in the be of relatively greater 1 same figure, said strip is completely insulated from the bed by means of a layer of suitable insulating material interposed between the same and the bottom and walls of the channel 16 formed in said bed to receive the strip. I also consider it desirable, although not necessarily essential, to provide means for cooling this strip and to this end two channels 17 are cut in the underside thereof and tubes 18, preferably of copper or brass, are laid in such channels, such tubes being connected across at one end of the strip and their ends projecting at their other end so as to afford an external connection for circulating therethrough a stream of water or suitablecooling liquid.

As shown in Figs. 1 and 2, the bars 12 are longer than the seam or line of weld; in other words, they are adapted to extend at their respective ends some distance beyond the adjacent sides or outer edges of the sheets 1, and short blocks 20 of the same material, i. e. steel, as'said bars 12 are fitted between such ends thereof. Preferably blocks 20,

'which are approximately .of the same cross:

section as the bars, will be ermanently attached each to one of said ars and merely pressed against the other or in some suitable way detachably" held thereagainst soas to rmit of the ready separation of the two hdrs in setting up and disassembling the mechanism. As a result of the construction just described, a magnetic short circuit is. provided which will give an easy path beyond the farthest point at which. the welding may be done.

With the same object in view, viz., to provide a In et-ic short circuit in the steel bed 4, it,w1ll be observed that the so-called fire strip 5 stops short of the end of such bed, prefera 1y :1 trifle within the ends of the space defined by such "blocks 20"thus attached to the clamp bars 12. It will further be noted (see Fig. 1) that the positive lead 21, through which the incoming current is supplied to said bed, is divided into two'branches 22 and 23 that are respectively connected with opposite ends of saidfire strip 5. Moreover, while a fixedresistanoe 24 is inter d in such first branch, :1. variable, i. e. ad ustable, resistance or rheostat 25 is interposed insaid branch 23. These resistances are of such character that they may-either be balanced, thus causing the incoming current to enter'the fire strip in a proximatelyequal amounts at the respecti ire endsof such strip, or by cutting in res stance or cuttmg it out b proper manipula tion of rheostat 25, suc current may be caused to flow in preponderating amount to one end or the other of such strip as desired.

It will further be noted that at all times, due to the fact that the incoming current reaches the are by way of the path defined by said fire stri it is caused to turn at substantially a rig t angle at the point directly beneath the electrode 6 or in other words at the point where the arc is formed, this irrespective of the position of the electrode longitudinally of the work. The magnetlc condition, due to the incoming current, thus becomes a known factor and can be dealt with accordingly. At the same time by regulating the amount of current supplied to the respective ends of the strip 5, the increase in distance between the arc ande-ithcr end and the corresponding decrease in distance between such are and the other end, as the arc advances along the work, may be balanced so that no change in magnetic condition will occur due to variation in the flow of current to the are, but this condition likewise can be maintained substantially constant by simply adjusting rheostat 25. i In the absence of I ends of clam bars 12, the magnetic efi'ect of such bars 1s such that the'flow of the arc will be toward the middle of said bars when blocks 20 bridging the the arc approaches either-end,- In other words,

the arc will tend to blow forwardly when it is located near, one end of the space between distance beyond the respective limits of travel of the arc to avoid any tendency forconstriction of such magnetic flux.

Under the conditions thus existing in my improved mechanism, it will be seen that if thecurrent enters from both ends equally, or in 1 'redeterm'ined relative amounts, the arc wil have very little tendency to blow in either direction, if 1t is operating roperly. The effeet of the hot spot as a actor accordingly becomes negligible since this can be taken care of by operating the are at a proper speed.

The direction of the incoming current can of course be controlled by means of the divided connection from the positive lead to the-fire strip 5, one branch of such lead having a rheostat therein. 1

It is to be remembered that the incoming current is just as potent in tending to distort the current out of the path coming to the electrode as it is tending to: distort the are.

Therefore, if the arc is being distorted, thereis just as much pressure trying to distort the current. In my improved-mechanism, however, matters are so arranged specificia'lly by electrically insulatingthe fire strip from.

the bed, that it is impossible for the current to be distorted out of a certain set path which will give theresults desired, so far as the. so.

blow of the arc is concerned and the latter will not vary because of the reaction of the are on the incoming current.

- Where the work consisting of sheets 1, for example, as shown in Figs. 3 and 4, contacts in part with the bed 4, there will of course 7 substantially entirely elminated by the modification in construction shown .in Fig. 5. Here it will be seen that the. upper surface of the bed 4. is cut away on either side of the fire strip 5 or rather of the channel 16 where in such strip is embedded so as to leave a substantial clearance space 27. \Vhere the sheets 1 are of such extent that they require to be supported beyond their edge portions which rest on the fire strip 5, this may be accomplished by inserting ribs 28 of insulating material in the bed 4, such ribs preferably running longitudinally of the bed, i. e. parallel with the fire strip.

In place of so constructing the clamp bars 12 as to constitute thereof a closed circuit for the magnetic flux set up by the are, such bars resting stationarily on the work but extending beyond the respective limits ot travel of the are so that the magnetic conditions due to the flux set up in such clamp bars will not vary within such limits of travel, I may enclose the arc with a movable magnetic damper that is carried along with the are. In Fig. 6 a form of mechanism incorporating such a movable magnetic damper 30 is illustrated, the other parts of the apparatus remaining substantially the same as before. Such. damper consists essentially of an open steel frame of general annular term slidably or otherwise movably supported upon the bed 4. If desired bars similar to bars 12 may also be employed but these will then be limited in to the clamping action previously referred to. Such movable magnetic damper will in any event render more or less negative the effect that such bars, or other corresponding parts of the apparatus, would otherwise have as a pathway for the flux set up by the passage of the'current through the are. A copper plate 31, corresponding in function to the bases 13 of the bars 12 in the previously described form of apparatus, closes the bottom of the frame 30, save for an approximately central opening 32 through which the arc is struck.

If desired to adda positive controlling factor to the magnetic eonditionssurrou nding the arc,-I may employ a solenoit 33 preterably disposed as shown in Fig. 6; i. c. said; solenoid is'adjustably attached to the electrode holder 7 by means of (211111115534 and 35 so as to permit the angularly projecting armature 36-to be brought into necessary proximity to the are. A sultable current being thereupon passed through said'solenoid, obviously an in dependent magnetic field may be created to hold or deflect the are as may be desired.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the means and the steps herein disclosed, provided those stated by any one of the following claims or their equivalents be employed.

I therefore particularly point out and dis tinctly claim as my invention 1. In metal working by electricity, the steps which consist in establishing an are between the work and a suitable electrode, relatively moving such work and electrode to cause the latter to follow the line to be welded, and surrounding such arc with a. closed circuit for flux set up by flow of current through such arc. I

2. In metal working by electricity, the steps which-consist in establishing an are between the work and a suitable electrode, relatively moving such work and electrode to cause the. latter to follow the line to be welded, and surrounding such are with a. relativelystationary closed magnetic circuit for flux set up by flow of current through such are. r

3. In metal working by electricity, the steps which consist in establishing an arc between the work and a suitable electrode, relatively moving such work and electrode to caus'ethe latter to follow the line to bewelded, and supplying the incoming current to the are through the work at opposite ends of the path traversed thereby.

4. In met-a1 working by electricity, the steps which consist in establishing an are between the work and a suitable electrode, relatively moving such 'work and electrode to cause the latter to follow the line to be welded, supplying the incoming current to the are through the work at opposite ends of the path traversed thereby, and varying the current thus supplied so astsubstantially to balance the magnetic effect of the flow thereof from such ends, respectively.

5. In metal working by electricity, the steps which consist in establishing. an'arc between the work and a suitable electrode, rel: atively moving such work and electrode to cause the latter to follow the line to be weld-" ved, surronndmg such are with a closed circult for flux set up by. flow of circuit through such arc, and supplying the incoming current to the are through the work at opposite ends of the path traversed thereby.

' t. In metal workingQ-by electricity, the steps which consist in establishing an are between the work and. a suitable electrode. relatively moving such Work and electrode to cause the latter to follow the line to be welded, surrounding such are with a closed circuit for flux set up by flow of current through such arc, supplying the incoming current to the are through the work at opposite ends of the path traversed thereby, and varying the current thus supplied so-as substantially to balance the magnetic effect ofthe flow thereof from such ends, respectively.

7. In arc-welding mechanism,the combination of a suitable bed for supporting the work, a strip of conductive material carried by but insulated from said bed, said strip being adapted to contact with the portion of the work to be welded, and means for supplying the incoming current connected to said strip. a

8. In arc-welding mechanism, the com bination of a suitable bed for supporting the work, a strip of conductive material carried by but insulated from said bed, said strip being adapted to contact with the portion of the work to be welded, and a branched lead for supplying the incoming current to said strip, the branches of said, lead being con nected with the respective ends of said strip..

9. In arc-welding mechanism, the combination of a suitable bed for supporting the work, a strip of conductive material carried by but insulated from said bed, said strip being adapted to contact with the portion of the work to be welded, a branched lead for supplying the incoming current to said strip, the branches of said lead being connected with the respective ends of said strip, and

means adapted to vary the flow of current throu h such branches.

10. n arc-welding mechanism, the combination of a suitable bed for supporting the work, a stri of conductive material carried by but insu ated from said bed, said strip being adapted to contact with the portion of the work to be welded, a branched lead for supplying the incoming current to said strip, the branches of said lead being connected with the respective ends of said strip, and an adjustable rheostat in one such branch.

11. In arc-welding mechanism, the combination of a bed of steel for supporting the work, a copper strip carried by but insulated from said bed, said strip being ada ted to contact with the portion of the wor to be welded and terminating short of said bed at each end, and means for supplying the incomin current to said stri 12. n arc-welding mec anism, the combination of a bed of steel for supporting the work, a copper strip carried by but insulated from said bed, said strip being adapted to contact with the ortion of the work to be welded and terminating short of said bed at each end, liquid circulating means associated with said strip for cooling same, and means for supplying the incoming current to said strip.

13. In arc-welding mechanism, the combination of a bed of steel for supporting the work, a copper strip carried by but insulated ing current to said strip.

14. In arc-welding mechanism, the combination of a suitable bed for supporting the work, an electrode and holder therefor movablerelatively to said bed in a longitudinal direction, and means constituting a closed magnetic circuit spaced from but disposed to surround the arc between the work and said electrode throughout the. path of travel of the latter.

15. In arc-welding mechanism, the combi-' nation of a suitable bed for su porting the work, an electrode and holder t erefor movable relatively to said bed in a longitudinal direction, two bars disposed one on each side of the ath of'travel of said electrode and adapte to rest on the work to hold the latter in place, and blocks connecting the corresponding ends of said bars and forming in conjunction therewith a closed magnetic circuit. 7 16. In arc-welding mechanism, the combination of a suitable bed for supporting the work, an electrode and holder therefor movable relatively to said had in a longitudinal direction, two bars disposed one on each side of the path of travel of said electrode and adapted to rest on'the work to hold the latter in place, and blocks detachably connecting the corresponding ends of said bars and forming in conjunction therewith a closed magnetic circui 17 In arc-welding mechanism, the combination of a suitable bed for supporting the work, an electrode and holder therefor movable relatively to said bed in a longitudinal direction, two steel bars disposed one on each side of the path of travel of said electrode and adapted to rest on the work to hold the latter in place, the ends of said bars extendin beyond the limitof travel of said electr e in each direction, and blocks of steel connecting the corresponding ends of said bars and forming in conjunction therewith a closed magnetic circuit.

18.. In arc-welding mechanism, the combi-- nation of a suitable bed for supporting the work, an electrode and holder therefor movable'relatively to said bed in a longitudinal direction, two steel bars disposed one on each side of the path of travel of said electrode and adapted to rest on the work to hold the latter in place, said bars having copper bases for contacting with the work, and a copper strip carried by but insulated from said bed, said strip being adapted to contact with the work on theopposite side from said bar-bases.

19. In arc-welding mechanism, the combination of a suitable bed for supporting the work, an electrode and holder therefor movable relatively to said bed in a longitudinal direction, two steel bars disposed one on each 5 side of the path of travel of said electrode and adapted to rest on the work to hold the=latter in place, said bars having copper bases for contacting with the work, and a copper strip carried by but insulated from said bed, said strip being adapted to contact with the work on the opposite side from said bar bases and the latter-being formed with laterally projecting toes adapted to overlie said strip.

20. In arc-welding mechanism, the combination of a suitable bed for supporting the work, an electrode and holder therefor movable relatively to said bed in a longitudinal direction, and two strips of material having 'elatively high heat conductivity disposed one on each side of the path of travel of said electrode and adapted to contact with the work,

21. In arc-welding mechanism, the combination of a suitable bed for supporting the work, an electrode and holder therefor movable relatively to said bed in a longitudinal direction, and two copper strips disposed one on each si'deoftlie path of travel of said electrode and adapted to contact with the work.

22. In arc-welding mechanism, the combination of a suitabie bed for supporting the work, an electrode and holder therefor movdirection, two copper strips disposed one on .each side of the path of travel of said electrode and adapted to contact with the work, and means connected with said strips for pressing the same thus to the work.-

23. In arc-welding mechanism, the combination of a suitable bedfor supporting the work, an electrode and holder therefore movable relatively to said bed in a longitudinal direction, two copper strips disposed one on each side of the path of travel of said electrode and adaptedto contact with the work, and rigid bars mounted on said strips respectively for pressing the same thus to the work.

24. In arc-welding mechanism, the combiwork, an electrode and bolder therefor movable relatively to said bed in a-longitudinal direction, two copper strips disposed one on each side of the path of travel of said electrode and adapted to contact with the work, and rigid steel bars mounted onsaid strips respectively for pressing the same thus to the work. 1

25. In arc-welding mechanism, the combination of a suitable bedfor supporting the work, an electrode and holder therefor movable relatively to said bed in a longitudinal direction, two copper strips disposed one on 5 each side of the path of travel of said electrode and adapted to contact with the work,

able relatively to said bed in a longitudinal nation of a suitable bed for supporting the' and rigid steel bars mounted on said strips respectively for pressing the same thus to the work, said bars being connected at their ends to form a closed magnetic circuit.

26. In arc-welding mechanism, tl1econ1bination of a suitable bed for supporting the work, an electrode and holder therefor movable relatively to said bed in a longitudinal direction, two copper strips disposedone on each side of the path of travel of said electrode and adapted to contact with the work, and another copper strip carried by but insulated from said bed, said last-named strip being adapted to contact with the work on the opposite side from the two first-named strips.

27. In arc-welding mechanism, the combination of a suitablebed for supporting the .work, an electrode and holder therefor movable relatively to said bed in a longitudinal direction, two copper strips disposed one on each side of the path of travel of said elec trode and adapted to contact with the work, and another copper strip carried by but insulated from said bed, said last-named strip being adapted to contact with the 'work on the opposite side from the two first-named strips and the juxtaposed edges of said firstnamed strips overlying said last named strip.

28. In arc-welding mechanism, the combination of a suitable bed for supporting the work, an'electrode and holder therefor movable relatively to said bed in a longitudinal direction, two copper strips disposed one on each side of the path of travel of said electrode and adapted to contact with the work,

and another copper strip carried by but insulated from said bed, said last-named strip being adapted to contact with the work on the opposite side from .the two first-named strips and the juxtaposed ed es of said firstnamed strips overlying said ast named strip and having their upper corners beveled.

29. A work-clamping device for use in arc welding, comprising a strip of material having a relatively high heat conductivity designed to contact with the work alongside the line being welded and a bar mounted on said strip for pressing the same to such work.

30. A work-clamping device for use in arcwelding comprising a copper strip designed to contact with the work alongside the line being welded, and a bar mounted on said strip for pressing the same'to such work.

31. A work-clamping device for use in arcwelding comprising aeopper strlp deslgned to contact wlth the work alongside the line beng welded, and a bar mounted on said str p for pressing the same to such work, said strip projecting laterally beyond said bar.

32. A work-clamping device for use in arcwelding comprising a copper strip designed to contact with the work alongside the line being welded, and a bar mounted on said strip for pressing the same to such work, said strip III beveled.

33. A work-clamping device for use in are-welding, comprising a steel bar provided with a base on the edge designed to contact with the work, such base being composed of a metal having a relatively high heat conductivity.

34. A work-clamping device for use in arcwelding, comprising a steel bar provided with a copper base on the edge designed to contact with the work.

35. A work-clamping device for use in arcwelding, comprising a steel bar provided with a copper base on the edge designed to contact vwith the work, such base being formed with a laterally projecting toe.

36. A work-clamping device for use in arc-welding, comprising a steel bar provided with a copper base on the edge designed to contact with the work, such base being formed with a laterally projecting toe beveled on its upper side. i

37. A work-supporting bed for use in arc welding, comprising a bed, proper, of steel, and a copper strip, carried by but insulated from said bed, wherewith' the work may directly contact.

38. In arc-welding mechanism, the combination of a bed for supporting the work, an

electrode and holder therefor movable relatively to said bed in a longitudinal direction, two strips of metal having a relatively high heat conductivity designed to contact with the work alongside the line being welded, means adapted to press said strips to the i work, and another strip of similar metal carried by said bed and adapted to contact with the work on the opposite side thereof from the two first-named strips.

39. In are-welding mechanism, the combination of a bed for supporting the work,

an electrode and holder therefor movable" relatively to said bed in a longitudinal direction, two strips of metal having a relatively high heat conductivity designed to contact with the work alongside the line being welded, means adapted to press said strips to the work, and another strip of similar metal carried by said bed and adapted tocontact with the work on the opposite side thereof from the two first-named strips, the latter being arranged and constructed partially to overlie the third strip.

40. In arc-welding mechanism, the com bination of a bed for supporting the work, an electrode and bolder therefor movable relatively to said bed in a longitudinal direction, two strips of metal having a relatively high heat conductivity designed to. contact with the work alongside the line being welded, bars mounted on said strips, respectively, for pressing the same to the work, and another strip of similar metal carried by said bed and adapted to contact with the work on'the opposite side thereof from the two first-named strips.

41. An electric arc welding apparatus wherein a weld is produced by relative movement between an arc and a work support comprising a backing member, characterized by the fact that said backing member includes a base of magnetic material provided with an inlay of material possessing high heat conductivity along the line of relative movement between said are and said member, said mag-' netic base beingadapted to engage the work to be welded on each side otsaid inlay to produce amagnetic circuit of relatively low reluctance through the work and the backing member.

42. An electric arc welding apparatus,

wherein a weld is produced by relative movement between the .work and an electric are, provided with a backing member including a steel base with an inlay of copper along the line of said relative movement, said magnetic base being adapted to engage the .work to be welded on each side of said inlay to produce a magnetic circuit of relatively low reluctance through the work and the backing member.

43. A backing member for use in electric arc welding comprising a base of magnetic material and an inlay of material-possessing high heat conductivity along the line ofthe weld, said magnetic base being adapted to engage the work to be welded on each side of said inlayto produce a magnetic circuit of relatively low reluctance through the work' and backing member.

' 44. In metal working by electricity, the steps which consist in establishing an are between the work and a suitable electrode, relatively moving such work and electrode to cause the latter to follow the linev to be welded, and surrounding such are with a closed flux circuit.

45. In metal working by electricity, the steps which consist in establishing an are between the work and a suitable electrode, relatively moving such work and electrode to cause the latter to follow the line to be welded,

and surrounding such are with a relatively stationary closed flux circuit.

46. The method of electric arc welding which comprises adjustably controlling the angular relation of the arc to the work by directing the flow of welding current from a plurality of spaced points arranged relative- 1y to the are so that such flow. of current through the work or its support in angular relation to the axis of the electrode produces the desired directional efi'ect on the are.

47 In arc welding mechanism, the combinati on of a welding electrode adapted to be presented in arcing relation to the work and movedrelatively thereto along the line to be welded, a conductor for welding current having contact with the work or its support, and

a bar of metal disposed alongside and substantially parallel with the path of travel of the are, said bar having such a degree of heat conductivity and extending away from the work in such close and unvarying proximity to such are as to restrain the tendency of such are to wander to the corresponding side of such line of travel.

48. In arc welding mechanism, the combi- 10 nation of a welding electrode adapted to be presented in arcing relation to the work and moved relatively thereto along the line to be welded,- a conductor for welding current having contact Withthe work or its support, and a bar of metal disposed on each side and substantially-parallel with the path of travel of the arc, said bars having such a degree of heat conductivity and extending away from the work in such close and unvarying proximity go to such are as to restrain the tendency of such are to wander to either side of such line.

' 49. The method of electric arc welding which comprises adj ustably controllin the angular relation of the arc to the W015; by

directing the flow of welding current from a plurality of points through the work or its support in angular relation to the axis of the electrode, and varying the amount of current flow from at least one of said points.

Signed by me, this 11th day of June, 1931.,

- JAMES F. LINCOLN.

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