USRE16804E - Electric butt-seam welding and apparatus therefor - Google Patents

Description

Nov. 2K9, 1927.

F. L. sEss|oNs y ELECTRIC BUTT SEAM WELDING AND PPARTUS THEREFOR Filed Nov. 5. 1925 3 Sheets sheet l VIIIIIL Nov. 29, 1927. Re. 16,804

F. l.. sEssloNs EIECTRIC BUTT SEAM WELDING AND XPPARATUS THEREFOR or'ginal Filed Nov. 5,' 1925 5 Sheets-Sheet 2 lll Mmmm lull' Nov. 29. 1927. Y Re. 16,804

.F. L. SESSIONS ELECTRIC BUTT SEAM WLDING AND APPARATUS THREFOR S5 Sheets-Sheet 3 Original Filed Nov. 5. 1925 -Reima! Nov. 29, 19427.

UNITED; ysiuirlas FRANK LSESSIONS, OF LAKEWOOD, OHIO.

ELECTRIC BUTT-SEAN: WELDING AND APPARATUS THEREFOR.

Original No. 1,630,866, dated Hay 31,1927, Serial No. 67,063, led November 5', 1925. Application for reissueled August 22, 1927., Serial No. 214,760.

Among the objectsl of my invention are the pro'vlsionof anew and useful method of progressively, electrically welding together the contacting surfaces of an open butt-seam in metal; the .provision of means for carry'- ing out, the above mentioned method; the provision of a progressive; Aelectr1c,tseain Welding machine havingv parallel, spacedapart electrodes co-extensive witlithe seam to be welded the rovision 4of a progressive, electric, seam-*Wel ing machine having parl allel, spaced-apart electrodes adapted to have the Work disposed upon or adjacent to them Withlthe surfaces of the seam-cleft in .abutting registerV opposite and .centrally of the space between'the electrodes; the provision of means vfor applying localized pressure to the work upon opposite sides of the seam-cleft to press small areas of the surfaces of the'work into good electrical contact with the electrodes adjacent to the seam# cleft; the provisionof means for progressively movin the points of application of such localize pressure along the work parallel and .adjacent to 'the seam-cleft; the

provision of means for pressing the seamcleft surfaces' together; the provision of a progressive, electric, seam-welding machine having electrodes stationary with respect to the terminals of the electric circuit to whichv they are connected; the' provlsion of apro.

gressive, electric,- seam-welding machine in which 'there is no relative traversing m'ovc' ment between the electrodes and the worklongitudinally of the seam-cleft; and the provision of a progressive,'electric, seamweld-ing machine in which the work may con- 'tact With'relatively light pressure with the electrodes upon opposite sides of the seamcleft throughouta considerable length thereof while relatively heavy pressure is applied to force the work and the. electrodes into good electrical contact at localized substantially directly opposite points adjacent to the seam-cleft to Vcause the current''low to be largely concentrated in a narrow path or heat zone in the work across the seam-cleft between the points of localized pressure.

Heretofore it has been proposed to'proygressively, electrically butl'rweld the contacting surfaces of an open butt-,seam in metal but, so far as I am aware, parallel;

spaced-apart electrodes, co-ex-tensive with the seam Ato be welded have not been em ployed inprogressive, seam welding. In-

stead, electrodes, usually revoluble rollers, have been employed which contact with small areas of the work on opposite sides-of the 4seam-cleft and aremoved progressively along the work parallel and adjacent tothe seam-cleft.

Preferably, in are stationary, parallel, spacedapart, conductor bars. They should be strong and well supported to properly withstand the .pressure necessary'to make good electrical contact between the electrodes and the Work. The work is placed so that it rests upon the velectrodes `or closely adjacent to them' with the seam-cleft surfaces pressed firmly together and disposed centrally over the space betweenjthe electrodes. Localized pressure is thenapplied to the Work to press small surface areas of it into good electrical contact With the electrodes at two substantially immediately opposite points along the seamcleft, adjacent to the seam-cleft. The electrodes are then energized and relative traversing movement of the localized pressure and the work is effected alon and parallel with the seam-cleft.- Electric current of great density is thus caused to flow in the work in a narrow Apath, or heat zone across the seam-cleft between .the surfacesbf the electrodes that are subjected tothe localized pressure. As the localized pressure is traversed along the seam-cleft, the heat zone moves with it and the seam is progressively Welded. During the welding operation the seam-cleft surfaces should be pressed'lirmly together in the heat zone. This may be done by applying localized pressure to force them together at the heat zone or by pressure distributed throughout a length of the seamcleft as described in my lapplication Serial No. 62,543, filed October 15th, 1925.

Heretofore in progressive seam welding by the electrical resistance method, roller electrodes Vhave been employed vto'traverse the work adjacent the seam-cleft whileprogressive localized pressure has been applied to. progressively force the edges of the seamcleft together adjacent the points of'contact of the electrodes. I have found that if .the seamcleft be firmly -pressed together throughout the length of the seam,- to be welded, a good weld can be made by causing electric Welding current in suitable volume to flow across the seam-*cleft atone point and traversing that point progressively` inventionithe electrodes i along the seam-cleft. This principle of tacts;a1ar'gerangeof sizes of work 1may be` welding ,that I believe to be first disclosed handled in the same machine; and, by the No. 62,543,may be utilized in my present inextended tov new fields of usefulness;

in my above identified application, Serial use -of my invention, electric welding may vention. The foregoingv and other'objects and ad- I do not limit my invention to the utilizavantages are attained by the use of my in tion of this principle as, it willbe obvious to vention described in this specicatlon and those -skilled in the art that localized pressuremay be applied to 'force the surfaces of the seam-cleft together in the heat zone only,

built in accordance with my invention and especially when welding tubes or large (ilyinders and employing the wellknown nlike seam-vuide's in the open seam-cleft ahead of the we ding zone that are used in tube welding machines to position and align the seam-cleft centrally between the electrodes.

Preferably the rateof vprogress of the localized pressure and resultant heat zone should be from 30to 100 or more feet per minute depending upon the thickness of the workv and tle frequency of the alternating J current employed. When using cycle current, I have found that sheet steel about' fifty-thousandths of 'an inch thick can be properly welded at from 30 to 100 `feetl per minute. `Possibly a'neven greater range of speed will b`e found practicable under favor- Vable conditions.

yIt will be understood that I do not limit my invention toa minimum speed of welding of 30 feet per minute as I am aware that rog'ressive` electric butt-seam welding has n successfully done at much slower speeds upon Parpart welding machines built in accordance with Patentla` 658,741 and upon machinesbuilt in accordance with my patent application, Serial No. 590,884, in both of w ich machines then Work l is traversed through suitable supporting and guidin devices past a pair of roller electrodes w ich contact with the work upon opposite sides of shown in fthe accompanying drawings, in which Fig.' 1 is` a.

side elevation vof a machine Fig. 4 is a portion of Fig. 3 drawn to a lar er scale;

igf5 is a fragmentary vertical cross section on line V-V of Fig. 1 but'drawn to a larger scale;

Fig. 6v is a vvertical cross section on line s VI-'VI of Fig. l3;

y Fig. v7 is a ragmentary view showing a ar ',modifieation of the v'pressurel roller mounting; l

Fig. 8.is a view similar to Fig. 7 showing a further modification of the pressure roller bar mounting; A Fig. 9 is a fragmentary view showing another form of pressure roller bar;

Fig. 10`is a Vsection on line X-X 'of Fig 1;

Fig. 11 is a fragmentary plan view on line XI-XI of F-ig. 3;,

Fig- 12- is a fragmentary section on line XII- XII of Fig. 7; and

Fig. 13'is a section on line XI II XIIIv of Fig. 9. v

Referring to the drawings, a welding the lseam-cleft closely adjacent thereto, and transformer 1.of any suitable internal conpressure'is a plied to close the seam-cleft kstruction andv electrical connections may beA substantially 1n the plane of Contact of the employed. Usually, transformers for this electrodes with the work. class of weldin lare provided with single turn Among the advantages of my invention seconda-ry windin s ada ted to develop from are two to six volts epen in upon the thickness of the stock to be Welded and the speed` Small 'electric-al losses lletween the welding transformer and the work due to the di at' which it is to be welded. The primary rect contact vof the work with thestationary windings of the transformer may be enerterminals of the welding circuit without ingized from any suitable source of alternattervening 'revoluble or other moving eleclng current4 such as the, 'ordinary service trodes; simplifiedV construction employing dinesat the customary potentials. The secthe smallest possible number of joints in the welding circuiti; substantial reduction in electric power and ener re uirements cornpared to` other metho s an apparatus on accountof the decreased voltage drop be' tween the welding transformer andvl the Work; substantial savings both in the first cost. of the machine and in repairs and maintenance due to the .avoidance of the use of collector rings and brushes; my linvention may be embodied. in a machine constructed without any sliding, electric .conf

circuit the secondary winding.` The trans- 4 the transformer top housto the 'top housing -5 and these bolts should also be suitably insulated so as not to Short l lac . coil 2 and primary coils 9 may be insulated \movably in known manner and may be -supported by the secondary conductor casting as shown in the drawings, or other means may be provided for supporting them such, for instance, as the ribs projectinginwardlyf from the walls of the main houslng L11 of 'the transformer and engaging the core clamps 8". The. top housing 5 maybe resecuredto the main housing ll'by means of bolts 12. It will be understood that it is important to have the secondary terminals 3-4 accurately aligned vand positioned and firmly held in fixed position.

The transformer may be oil, air blast or otherwise cooledv if desired. Cooling-fluid ducts such as 3*4" may be provided in the secondary terminal electrodes if desired.

' The secondary terminals 3-4 of the transformer "nay be provided with i'anges 13%14,

accurately4 machined to contact with and. support the electrode bars 15-16. Insulation 17, such, for instance, as bake1ite, may.'

be interposed between the op .site faces of the terminals 3-4 and electro e bars 15--16.

Insulated throughbolts 18 may be employed to clamp the terminal 'an es 13-14, electogether.

trode bars -16 and insu ation 17 firmly Cap screws 19-20 may be employed to draw the? electrode bars 15- 16 into good electrical co-ntactwith the flanges 13-14 of the transformer secondary terminals. Renewable work-contacting strips 21-22 may be detachably secured to the electrode bars 15--16 by suitable meanssuch as the cap screw/s` 23-2a The electrode bars 155-16 and the strips 21-22 maiylT be made of any desired or necessary lengt to accommodate the worl: to be welded. It will be understood that the workcontactingl strips 21-22 may be dispensed with if desiredand the work may be made to contact directly with the tops of electrodes l-ld In such insta-nce, however, the electrodes should be shaped-so as to be spaced about an eighth of an inch apart adjacent to the wo-rkseam-cleft, as the work-contacting strips are shown spaced at 25. The space 25 between the opposite edges of the electrode contact surfaces may be varied somewhat with the thiclmess of the work as in the known use of roller electrodes.

.Provision should 'be made for 'supporting r and clamping the work and for pressing the contacting surfaces of the seam-cleft together. In the drawings, work platens 26- 27 are disposed upon opposite sidesof the electrodes and extend toward them over the vdirect from the floor or other suitable support.

edges firmly together, I prefer to employ pairs of rollers shafts such as 6 mounted in adjustable bearings 36-37 and held in adjusted position by means such as the step screws 38-39. The top rollers 31-33 may have their shafts extended and ratchet wheels 4() may be mounted upon and secured to thel shafts. Suitable levers 41-42 may be provided and pawls .43-44 may be pivotally secured to the levers bymeans of olts 45. Reversible pafwls 43-44 may be provided to en age the teeth of ratchetv wheels (pre erably, there should b e a ratchetl wheel mounted on each end of Ithe shafts of rolls :5l- 33) for rotating the rolls in either direction, or'the pawls ma be disengaged from the ratchet wheels an the rolls may then be allowed to rotate freely as, lfor instance, when the-work is bei fed through the rolls before and after making a weld.V Springs -46-47 or equivalent 'means may be employed to exert yielding torsional force upon the levers -30-31 and 32-33 having ing pressure upon the work sheets 48--49 to force the contacting edgesxof the seam-cleft 50 together.

Seriesof spring-actuated plungers 51-52 may be employed for the purpose of holding the work slightly above and out of contact with the tops of the electrodes or contacting strips 21.-22 until the pressure-roller 53 en- 41-42 and the co-acting rolls 31-33 respectlvely to produce yielding feedgagesthe work and forces it down into good electrical Contact with them. The springactuated plungers 51-52 may be mounted. in

suitable apertures in the work platens 26- 2'?, as shown in 3. hn'of oil may be smeared on the electrode surfaces or' on those shown at 34e-.35 in Fig.

los

the surfaces of the work that are 'to lbe y pressed into Contact with the electrodes 'to lrev'ent arcing between the electrodes 'the work where they may come together outside the Zone of the localized pressure..

p Preferably, asteel roller 53 or a pair of insulated rollers should be employed for pressing the work into good electrical contact with the electrodes or the contacting strips i-QQ if they,T be used. In the machine shown in the drawings a singie roller 53,

y preferably made of steel, is used, having a circumferential groove 53a. in the middle of its face. This groove 53EL spans the seamcleft 5() of the Work opposite the space be- 'tween theelectrodes so that the roller 53 operates to press upon the work upon/the opposite sides of the seam-cleft as a pair of axially spaced-apart rollers mounted upon a shaft would operate. If desired a pair of rollers may be used `and they may be insulated `from each other by insulation in the place of groove 53a and may be suitably in- -sulated from the shaft 53"-inA known manner.

It, is not essential that the halves of roller 53 be insulated from each other for the reason that the impedance of the current path through the work across the seam-cleft '6 between the electrodes is so much less than be not insulated from 'each other. The

use of insulated rollers will prevent'a tain'wastage of electric current. f

The purpose of the pressure-roller 53 is to ressv the work immediately between it Cel'- 15 an the electrodes into good electrical contact withvthe electrodes or the contacting strips 21`-22 if they be employed. .'lhis will cause electric current of great density and' volume to flow across the` seamcleft between the electrodes in the -narrow zone of pressure created' by the roller 753. To Weld the seam, the roller 53 is traversed along fthe. work, progressively `pressing it into good electrical contact 'with .the elec- 2&5 trodes adjacent to and parallell with the seam-cleft. The'ow of current, which is concentrated largely in the zone of the localized pressure of the roller 53 because the path of least resistance'between the electrodes liesin that zone, heats the contacting surfaces of the seam-cleft -and progressively welds them together coincidentally .with the movement of the zone of pressure.l Itwill be understood that the same' effect may be 35 had if the roller 53 be held in and the work andthe electrodes be traversed one position ast it, relative traversing movement oI the ocalized pressure of -the work upon the electrodes along the seam-cleft b.eing\what ,is required. v

' Various means maybe employed to force the pressure roller against `the work and cause it vto move progressively along thev scanf-cleft. One of such means is illustrated in Figs. 1 and 3 and various modifications of this means are illustrated in Figs. 7,8 and 9.

In Figs. l and 3 the pressure roller.53 is shown revolubly supported in bearings in a pressure roller support 54 which is secured to a supporting bar 55 which is -niounted for sliding movements in adjustable bearings 56. The bearings 561 are mounted in a suitable housing 58 which maybe supported upon a rigidbase frame or pedestal 59. To reciprocate the bar -55 longitudinally in its bearings and therebv cause the pressure roller 53 to progressively engage and press the work into good elec; trical contact with the electrodes, I prefer to employ such a mechanism as is illustrated in Fig. 1 in which a rack bar .60 is ,connected as at 61 to the roller support 54 so as to permitvertical adjustments of thelatter. Rack bar 60 and the contact (pressure applying and traversing means, includin roller 53, may be reciprocated back an suitable'train of reduction gearing driven by the motor 62- or other suitable means. The motor 62 may be mounted upon the forth longitudinally of itself by means of a I pedestal 59 and its motion may be transstopsand limit switches may be employed u for stopping the motor and the traversing movement of the pressure lroller and for opening the primary circuit of the welding.y transformer v1 at or near theends of its travel.

The electrode bars 115-'16 may be attached to the housing'58 to give-them additional support and rigidity. It will be understood that they should be insulated from their supports (except 4the transvformer secondary terminals) and from each other. In Figs. land 10, insulated bolts (S8-6.9 are shown passing through the electrode barsand llanges formed on housing 58 for aiding 1n supporting the electrcdes and in holding them in accurate position and v4in alignment with the path of movement of pressure roller 53. The work platens 26-27 may be providedwith legs 71 and foot flanges 72 which may be mounted upon the supporting pedestals 28-29 in suitable manne-r. ,l

Suitable ducts 73, 74, 75, may be provided in the shaft 53h-and pressure roller csupport 54, for the circulation of cooling fluid, in known manner.

In Figs.,'1 and 2 the b'ar 55 is shown mounted in adjustable bearings adapted to support the bar against transverse horizontal l-and vertical movements vbut to permit it to slide in the housing 58. The bearing blocks 56 are tapered as shown at' 7 6 to lit complement-al gibs 57 and have lugs 77 with clearance apertures for studs 78 which are secured-in the housing 58. .By adjustin nuts '79*80 which abut against the lugs 7 the bearing blocks may be adjusted to raise, lower and align'the bar 55 and consequently roller. 53. yAdjustable slide bearing blocks 8182 may be provided v`for supporting the bar 55 against'horizont-al transverse movement inhousing 58. For the adjustment of blocks 81,-82, set screws 83 may be employed in `well known manner.

Bearing blocks 84 may be provided for rack bar 60 as shown in Figs. 1 and 2. The 'rack bar may have side lianges 85 to support it in suitable apertures in housing 58. In ,Fig 7, the top bearings 86-86 of the pressure roller bar 87, are ieldingly held against upward movement. y springs 88.

meca-. u

of roll 53 on thevwork may bei .predeter-ttinsta ce .as continuous ori impulsive umminedrsy v.Adjustable non-yielding bearing' dir tional'currentmaybe employed if suitblocks 9O.a'nfd"gibsy 9 1, maybe .employed -fori i ableisourcesof supply ofsuchkinds of cur- Sprin tension. ad 89 may .c1-1 1'1fent, it will be understood'that any other. i provi ed whic maximumpressurel. sultahlel yform of. 'elctric current, such lfor.

-. a .I do not limit my invention tothe spe- .clic apparatus shownin the'drawings or to v bearing.` locks 92` and 4gibs 93 aredispose the .specific operationsdescribed,- as it will 'abover the pressurer-roller bar: v'vhile besobviousfto .those skilled? in: the art that springs 951-96 '-yieldingly supportthebar g'othermeansmay be employed lfor carrying in contact/with bearings,l 92 and prevent out my invention and. that thefunctions of rollen 53. from'. dropping down upon-A elecrts `elementsfjmiy be augmented 'ormodified trode oontact .strips .21-2 2 .when-the roller.. .Without'departing'from its scope. v. fis traversed be j ond.the'vrork 97, -f

ing 99.and the other-.Eis Connected by a iv' metal which consists in pressing said conoted link 100 -to the support 101 w ichictilig surfaces. together, causing the vmetal supportstheouter. end 'of the electrode bars.y adjacent .t0 and. upon;opposite sides of the forth by .therack bar 103Lwhichis actuated Cuii applying localized .pressure to saidl b pinion 104 and the driving mechanism as'- metal `upon .oppositesides ofthe seam-cleft s own. tOipreSSsmall areas ofthe surfaces ofsaid The pivoted link-.100 is detachablyconmetal into good electrical contactiwithsaid nected to, the su port 101'y and may be. kterminals .adjacent to .the seam-cleft, and swung up about te pivot '100", to permitI progressively traversing saidlocalized presthe work-to be placed in the machine over Sure of the metal upon said terminals parthe ends of the electrodes. With this conallel and adjacent to the seam-cleft. struction of machine, longitudinal seams in f 21A method of welding together the concylinders ma be welded as the cylinders tactmg surfaces' of an open butt-seam in can be readi y` placed upon and removed vmetal which consists in pressing said confrom the electrodes by swinging link 100 up out of the way. y lzed' pressure to said metal adjacent to and In Fig. 12 the insulated support for the `upon opposite sides of .the seam-'cleft to electrodes shown in Figs. 7 and 8 is shown press small areas of the surfaces of said in sec`tion. The electrode bars 1 05-106 l metal into good electrical contact with the are separated by insulation 107 Insulations terminals of an electric welding circuit 10S-109 insulate the electrodes 105-106 whereby'the flow of current between' said from the frame 110. Set screws 111 may terminals is largely concentrated in anarbe provided for aligning and securing the row path inthe metal across the seam-cleft electrodes in the frame y110 as shown.. between said areas of localized pressure, and

.Fig 13. is a section on line XIII-XIII of Flg. 9 `showing the manner in which the ends of the electrode bars 112-113 are supported and insulated in the frame 101'. The

electrodes are insulated from each other and from the frame as clearly shown in Fig. 13.

In the o eration of my invention,.the work plates such as those shown'at 48-49, Fig. 3, are preferably clamped'ufpon the platens 26-27 with the vsurfaces o the seam-cleft 50 in accurate meeting register and firmly pressed to ether.

In the rawings I have illustrated a machine having strai ht surfaced electrodes, but it will be obvious to those skilled in the art that they may be curved to accommodate correspondingly curved sheets such as are used in making metal bodies for automobiles, metal .receptacles or other bulged sheet articles. 'y f While I have shown and described my invention as `utilizing alternating electrlc The pressure roller snpport 102 fslides on `seamfcleftto contactwith the respective opthe .bar98 and may, be iuave1sed back and .fp0S 1te.terminalsy of fan electricwelding cirtacting surfaces together, applying l0c a1'y causing progressive traversing movement of lthe localized pressure of the metal upon said' terminals parallel and adjacent to the seam-cleft.l 3. In apparatus for progressively weldin together the contacting surfaces of an open butt-seam in metal, I parallel spaced-apart electrodes co-extensive with the seamto be welded adapted to support the work tobe welded with the surfaces of the seam-cleft of the space between the electrodes, means for applying localized pressure to the work .upon oppositesides of the seam-cleft to press small areas of the surfaces of the work into good electrical contact with said electrodes, and means lfor'causing progressive traversing movement of the legalized pressure of the Work upon said electrodes paralleland adjacent to said seam-cleft.

4. In apparatus for progressive] welding together the contacting surfaces o an open in abutting register opposite and centrally forpressing said contacting surfaces to? l sure {of l5 vinto good electrical contact with said elec'- f trodes; and means I for causing 1 progressive lbutt-seam in met-al, parallel spaced-apart electrodes "co-'extensive'- with the same tobe in abutting register opposite and centrally f' thespace between't e"electrodes,'emea1ns` gather, means forvwapplying localizedv prs;

Y sure to the'w'orkfupon opposite-[sides ofthe l I0 seamcleftto lpress small areas of the work traversin ymovemento` f"tl1e localized 'p resl the. work upon said electrodes parallel'and adjacentto said'seam-cleft." f f 5. In ap aratus fo'r 'progressively welding together-t e contacting surfaces of an open butt-seam in metal, kparallel spaced-apart electrodes' co-extensivel `with the 'seam yto be welded adapted to lsupport the'workj to be weldedgwith the surfaces of the seam-cleft in abutting register' opplosite and centrally of the space ybetween t e electrodes, A 'elding means for supporting the work out o 'contact kwith said'electrodes, means for applying localized pressure to the Work upon Aopposite sides of the seam-cleft-in opposition to said yielding means to ress small areas of the surfaces of the work into good electrical contact with said electrodes, and means for causing rogressive traversing movement of the locallzed ressure of the work upon said electrodes para lel and adjacent to said seam-cleft.

6. In apparatus for progressively welding together the contacting surfaces of a'n open butt-seam in metal, parallel spaced-apart ,v

electrodes co-extensive with the seam .to be welded adapted t'o support the'work to be welded with the surfaces of the seam-cleft in abuttin register opposite and centrally 'of the space etween the electrodes, means for y yieldingly supporting the work out of conthe space v ,between t tact with said electrodes, means for pressing together the contacting surfaces of the seam-cleft, means for lapplying localized pressure to the work upon opposite sides of the seam-cleft in oppositionto said yieldingV means to press small areas of the work into good electrical contact withv said'electrodes, and means for causing progressive traversing movement of the localizedv pressure of the work upon said electrodes parallel and adjacent to said seam-cleft. Y

7. In apparatus of the classdescribed, a source of supply of electric welding current, a pair of parallel spaced-,apart electrodes connected'to the terminals of said source of current supply, means .for supporting the work with ythe'surfaces of the seam-cleft in abuttingregister oplposite and centrally of e electrodes, and means for progressively applying localized pressure tothe-workl upon op osite sides of the seamcleft to .progressiveywress small areas ofA plying' localized contact with said electrodes.

the' `surfaces of the `visi-erik into good electrical -18;A In apparatusoff the classlzvdescribedvfa f transformer, `a of 'parallel rspaced-'apart electrodes electrically connected fto the -secondary terminals of said transformer adatvcdi-tofsul'nport.'the workto Vbe welded with the'y surfacesyof the seam-cleft in abutting register oppositerand centrally ofthe space between' theelectrodes, roller means fore ap' opposite :sidesl o Itheseam-cleft to! press tsmallfareasof the' surfaces of the workintoi" 'good electrical contact with "said, electrodes,

ing movement of aid roller means along theworkparallel and adjacenttosaid seamand means for causing 4progressive travers'- 9. .In -apparatus for iprogreivel welding I I i `together the contacting surfaces -o ainopen pressureto the work` upon butt-seam in metal, parallel spacedapart"- electrodes co-extensive with the seam to be welded adapted vto support the work to -be welded with-the surfaces of the seam-cleft in abutting registerj opposite and centrally of the space between the electrodes, means for applying localized pressure to the work upon vopposlte sides of the lseam-'cleft to press small areas of the surfaces of the work into good electrical contact withsaid electrodes,

and means for causing progressive traversa ing movement 'of the localized pressure ofhe work upon said electrodes parallel andA yadjacent to said seam-cleft. y

10. In apparatus for welding together the contacting surfaces of an openbutt-seam in metal, spaced electrodes co-extensive with the seamy to be welded .adapted to support the workito be welded closely adjacent toid seam with the surfaces ofthe seam-cleftA 1n abutting register-opposite and centrally of the space between the electrodes, means forf pressing said surfaces together, and

means for applying pressure to the work upon oppositevsidesof the seam-cleft to press the work. into good electrical contact with said electrodes.

l1.V In apparatus of the "class described,l a

source of supplyof electric welding current, l

a pair of parallel spaced-apart electrodes velectrically connected' to said source of' current supply, said electrodes being adapted floo a losr centrally of the space between the electrodes, r l

means for pressing said surfaces together, and means for Progressiv/ely applying localsides of the-seam-cleft to'press small areas of. the surfacesI of the work into good elec` trical contact with said electrodes. f

`ized pressure to the work upon opposite open butt-seam in metal which consists in supporting the metal on opposite sides of the seam-cleft closely adjacent thereto throughout the length of the seam to be `welded, pressing together the edges of the cleft together.

13. The method. of electrically. welding an open butt-seam in metal which consists in supporting the metal on opposite sides of the seam-cleft closely adjacent thereto throughout the length of the seam to be welded, holding the edges of the seam-cleft in abuttin register throughout the length to be wel ed` pressing the said edges into electrical contact, causing electricI current of large volume to flow across said seam-cleft, this current being caused to flow chiefly in a narrow path by localized pressure between the metal and the electrodes of the circuit supplying the electric welding current applied on opposite sides of and close to the seam-cleft and causing said path of current iow to progressively traverse said seam-cleft throughout the length thereof to thereby rogressively weld the edges of the seam-cle t together.

14. The method of electrically welding together the contacting surfaces of an open butt-seam in metal which consists 1n `supporting the Work closely adjacent to the seam-cleft, pressing the edges of the seamcleft firmly together simultaneously throughout the length of the seam to be welded, causing electric welding current to iiow across the seam-cleft,l this current being caused to flow chiefly in a narrow path by localized pressure between the metal and the electrodes of the circuit supplying the electric Welding current applied on opposite sides of and close to the seam-cleft, and traversing said current path longitudinally along the seam-cleft.

15. The method of Welding together the contacting surfaces of an open butt-seam in metal which consists vin pressing said contacting surfaces together, supporting them upon the terminals of an electric welding circuit which are elongated in the direction of the butt-seam, thework on one side of the seam-cleft being supported upon one `and the work on vthe other side of the seamcleft being supported upon the other of such terminals, and progressively applying localized pressure to the work to press small areas 'thereof upon said terminals and traversing said localized pressure parallel to the seam-cleft.

16. The method of electrically Welding an open butt-seam in metal which consistsin support-ing the metal onopposite sides of the seam-cleft closely adjacent thereto throughout the length of the seam to be welded, pressing together. the edges ofthe seam-cleft, causing the terminals of an electric weldinv circuit to progressively make good electrical-contact with small Aareas of the surface of the. metal upon the respective opposite sides of the seam-cleft to cause an electric current to flow across the seam-cleft in a narrow path that progresses along the seam-cleft with the progress of'the contact 0f said terminals with the metal and thereby progressively Weld the edges of the seamclcft together.Y

17. The method of welding together the contacting surfaces of an open butt-seam in metal which consists in pressing said contacting surfaces together, yieldingly supportingthe Work above and out of contactwith the terminals of an electric welding circuit Which are elongated -in the direction of the, butt-seam. the Work on one side of the scam-cleftjbeing supported above one and the work on the other side of the seamcleft being supported above the other of such 'terminals7 and progressively applying localized pressure to the work to cause it to yield towards said terminals and small areas of the work to make good electrical contact upon said terminals in the zone of said localized pressure, and traversing said localized pressure upon the Work parallel to the seamcleft.

18. In apparatus for progressively Welding together the contacting surfaces of an open butt-seam in metal, parallel, spaced electrodes co-extensive with Ithe-seam to be Welded, meansfor yieldingly supporting the workabove and out of contact with said electrodes with the surfaces of the seam-cleft in abutting register opposite and centrally of the space between the electrodes, means for applying-localized pressure to the work upon opposite sides of the seam-cleft to cause said work to yield and small areas of the surfaces thereof to be pressed' into good electrical contact with said electrodes and means for causing progressive traversing movement of said localized pressure parallel and adjacent to said seam-cleft.

In testimony whereof I hereunto affix-my signature.

Istarmi; L. sessions. i

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