US2040349A - Method and apparatus for fabricating metallic structure - Google Patents

Description

May 12, 1936. A. e. WAGNER METHOD AND APPARATUS FOR FABRICATING METALLIC STRUCTURES Filed Jui 15, 1935 5 Sheets-Sheet 1 IIIIIIllIlu INVENTOR.

n 6 GEM ATTORNEYS May 12, 1936. A. (5. WAGNER 2,040,349

METHOD AND APPARATUS FOR FABRIGATING METALLIC STRUCTURES Filed July l3, 1935 5 Sheets-Sheet 2 INVENTOR.

ATTORNEYS" May 12, 1 936. A. a. WAGNER METHOD AND APPARATUS FOR FABRICATING METALLIC STRUCTURES Filed July 13, 1935 5 Sheets-Sheet 5 OOOOGOOOO mvau/ 1N VENTOR ATTORNEYS May 12, 1936" I A G. WAGNER METHOD AND APPARATUS FOR FABRICATING METALLIV'STRUCT Filed July 13, 1935 Squats-Sheet 5 lii ATTORNEY.

Patented May 12, 1936 UNITED STATES PATENT OFFICE METHOD AND APPARATUS FOR FABRI- OATING METALLIC STRUCTURE Reading, Ohio, assignor of one-third to James G. Kyle and one-third to Fred C. Rosche,

bothof Reading, Ohio Application July 13, 1935, Serial No. 31,254

26 Claims.

The present invention relates to a method and apparatus for fabricating metallic structures and more particularly for producing fabricated cages,

sheets and the like for concrete reinforcement,

from cold drawn steel wire stock.

Cages may be formed of acontinuous spiral,

the coils of which are maintained in predetermined spaced relation by struts welded to the co'nvolutions thereof, or may be made by assembling a series 'of independent hoops, which may be held in place by struts extending thereacross. v

Flat structures when completed will have a plurality of lengths of wire arranged in substantially parallel relation, and with predetermined spacing,- the said lengths being held in place by cross wires, welded ateach crossing; or may be formed of a continuous length of wire arranged in zigzag formation and held in such formation by' strips extending thereacross.

In fact, fabricated sheets maybe formed,'and when completed, rolled and secured, to produce cages.

The present invention contemplates the 'assemblage of one set of wires, and the application thereto of the cross wires or struts.

It is also an object of the present invention .to provide in a single machine, a mechanism which is supplied with stock material and which turns out the finished product therefrom, rapidly, inexpensively and with practically no attention from an operator, other than to ensure adequate supply of material to the machine and to start andstop the operation thereof.

While the invention is subject to such adaptation as may be necessary to the accomplishment of the several objects, a preferred embodiment 'erein described is designed for the production of fabricated cages of steel wire, used in the rein-- forcing of concrete pipe, from a series of preformed, butt welded wire hoops which are held in position by cross or transverse steel wires welded at each crossing to the hoops.

To this end the main of an electric welding machine having means for drawing a length of wire from a supply roll of stock material, means being provided for straightening the wire so drawn, for measuring oil a. predetermined length thereof, forseverapparatus consists in the ing such predetermined length, and for welding the severed length to a series of hoops mounted on a rack adjacent a movable welding electrode, with a continuous rapid movement of such welding electrode, means also being provided, as an adjunct to the machine, to support the hoops in predetermined relation to the severed pieces.

Other objects include means to-synchronize operation of the welding transformer and the main motor of the machine, such that the one will not operate if the other has stopped; to

provide means for adequately cooling the weldihg electrode thereby preventing overheating; to insure a travel ofthe welding electrode at a satisfactory operating speed during welding and a return to its original position at'a higher rate of speed, thereby avoiding waste of time; and to insure accomplishment of the foregoing automatically and without special adjustment on the part of an operator.

To the attainment of the foregoing and other objects which will appear as the description pro- .ceeds, reference may be made'to the accompanying drawings, in which:

Fig. 1 is a side elevationof the assembled apparatus illustrating a completed cage, and the beginning of operations on a new cage;

Fig. 2 is a section along the line 2--2 of Fig, 1;

Fig. 3 is a side elevation, slightly enlarged, of the machine proper showing a partly completed cage and details of the driving mechanism;

Fig. 4 is an enlarged view of the welding head with parts broken away to show relation of the cutting or severing device;

Fig. 5 is a further enlarged elevation of the welding electrode and carriage therefor including diagrammatically, the wiringscheme;,

Fig. 6 is a section along the line 6-6 of Fig. 4;

Fig. 7 is a. section along theline 1-1 of Figs. 3 and 8; I

Fig. 8 is a fragmentary elevation from the side of the machine opposite that of Figs. 1 and 3 illustrating details of the driving'meehanism and also the operation of the cutting or severing device;

Fig. 9 is a detail in severing device;

Fig. 10 is an enlarged section on the line Ill-I0 of Fig. 8

The apparatus can best bedescribed by regard- 50 ing it as a series of cooperative work stations, or uni each of which has its own special function, and all of which are co-related and synchronized to each other through the medium of a common driving mechanism.

perspective of the cutting or Referring now more specifically to the drawings in-which like reference numerals designate like parts, and particularly considering Figs. 1, 3

and 4, there is illustrated a mechanism or unit A being located operatively beyond the feeding unit B.

The feeding mechanism B is arranged to pull a length thereof, predetermined in extent by the unit A, to a welding station E, where it will be severed by the mechanism D during the process of welding. after having been straightened during its passage past the station or mechanism C.

The welding head or station E is carried by the frame of the unit A, in such a location with respect to the aforementioned units as to receive the straightened, measured length of wire stock ready for fabrication into a cage.

Mounted adjacent to the welding station or unit E is a turn table G adapted to support a plurality of slidable cage racks, one of which will be supplied with a series of preformed hoops H while another is presenting a series of such hoops to the welding station. Upon complete formation of a cage, the turn table may be rotated and the finished cage removed from its rack which will then be ready to receive a new supply of hoops, in.- the meantime the rack which has just been supplied will be presented to the welding station This turn table, while not an essential component of the apparatus, nevertheless is an important adjunct, facilitating operations and func* ,tioning as a real time saver.

From this organization it will be evident that a strip or length of wire W, pulled by feed rolls in the mechanism B, through straightening rolls in the unit C, will be fed to a work supportin the welding unit E, and severed by a knife in the unit D whereupon a travelling electrode in the unit E may be brought into operation to weld the severed strip to the hoops H carried by the rack. .The rack will have ben removed from the turn table G to position on the work support of the-welding station.

Driving and control mechanism which is mounted a motor M. The motor M serves as a source of power for all mechanically driven is integral with a bell crank 26 which is pivoted to a link 21, in turn pivoted to one end of a rocker arm 28 fulcrumed on the side of the frame ii. The rocker arm 28 extends through an opening in the frame l5, and carries on its inner end a cam roll'29 by means of which the'arm is actuated in a manner hereinafter described.

An ofl'set plate 30 adiustably secured to the sideof the frame l5 serves to provide bearings for the outer end of the shaft 20 and for the outer end of a stub shaft 34, the inner end of which is J'ournalled in the frame. The stub shaft 24 carries gears 35 and 36, meshing with the gears 2| v and 22 respectively, and a gear 31, which in turn a strip of wire W from a source of. supply and feed meshes with a gear 38 rotatable on the end of a shaft 39 journalled in the side walls of the frame I5 and extending completely through the frame, with the ends thereof projecting from opposite sides. i

The gearing thus far described comprises a two speed, reduction gearing from the motor, and it will be evident that as the clutch member 23 is shifted by the yoke 24 into engagement with one or the other of the gear and clutch elements 2| or 22, that the gear 38 will be driven at one or another of two speeds, for a'constant of the motor.

,ment of the electrode carrier 44.

On the end of the shaft 4: at the opposite side of the machine from the sprocket 42 is a elements of the apparatus. The-sidewalls of the frame or housing I! are connected at the top bya platformll which serves to support a transformer T. The motor M is connected bya drive ing belt illto a pulley IS on one-side of the frame, keyed to a shaft 20. The shaft 20 extends entirely through the frame, projecting on the opposite side from the pulley, and serves to. supp rt a combined gear and clutch element 2| which is freelyrotatable on the shaft. Also mounted for free rotation on the shaft, and in spaced relation to the element 2| is a second gear and clutch element 22. Splined to the shaft 20 between the oppositely facing clutch elements 2| and 22 is a slidabie clutch member 23, operable by a yoke 2i. The yoke is carried by brackets 25 secured to the frame ll adjacent the shaft 20. a d

' apparatus,

gear 5| in mesh with a. gear 52, keyed to a shaft 53. Also carried by the shaft 52, is a sprocket 54 which is effective to drive a sprocket chain 56, whichchain drives a sprocket 51 keyed to the shaft 39. By this arrangement of gearing the shaft 39 is driven in synchronism with the shaft 42, which drives the movable electrode.

Wire stock feeding mechanism Keyed to the shaft 39, within the housing I! is a mutilated gear 58, illustrated in the present embodiment as having teeth over one-third of its circumference.

The purpose of this gear is to drive feeding rolls of the unit 3, which draw the wire stock from its source of supply and feed it through the in synchronism with movements of the electrode, and it is effective to feed a predetermined length of wire stock to the weldinl mechanism or unit E automatically.

The gear 58 also controls the change-speed yoke 24', andot'her elements of the apparatus. The side of the gear adjacent the root of the teeth is slightly higher than the remainder of the gear, whereby as the cam roll 2! rides upon the high surface, the machine will operate at slow. speed, but when the cam roll is traversing the remaining two-thirds of the gear the machine will operate at higher speed.

The teeth of the mutilated gear are arranged to mesh with a gear!!! mounted on ashaft I, which shaft also carries a gear if. This gear I operates through gears I2 and ii to drive a gear 55 (Fig. '1), in mesh with a feed roll driving gear 64. Gear $4 in turn actuatesja pair of gears 12 having a concaved end shaped to mate with gear 58 to is a wire straightening the periphery of surface 1| is formed on the side of the gear 58. The gears 58 and 58 and the parts 1l (1 12 are so proportioned and related that as'the lution the teeth thereon will have caused the complete a revolution, at which time the member 12 will come into contact with the sinand act to lock the gear 58 against further accidental rotation until such time as the teethof the gear 58 come into engagement therewith. This ensures an accurate feeding of the stock a predetermined distance for an operawhich will be will be necessary to'change the size of the gear BI, and in this connection it will be noted that the gear 82 is'carried by an adjustable bracket, permitting a take-up of clearance.

Wjre straightening mechanism Mounted in' advance of the feed rolls ,on the upper portion of a sub-housing on the frame l5.

mechanism C which comprises one set of grooved rolls 13 arranged such that a wire resting in the groove of one roll will also rest .in the groove of an adjacent 'disaligned roll, and a second similar set of rolls 14, the axes of the rolls inone set being located in a planeat substantially right angles to the plane of the axes of the other set. It will be quite evident from Figs. 1 and 3 that as the wire is drawn by the feed mechanism B from a supply roll (not shown) it, will be unrolled, unkinked and straightened prior to its movement into welding position.

Wire severing mechanism 7 Referring now particularly to Figs. 8 and 9, the mechanism for severing a strip of wire (the length of which is predetermined by the mutilated gear 58) from the main supply, is illus-' trated. This mechanism consists of a knife orshearing blade.15 slidable in suitable guides 16 which are located adjacent the guide opening 11 in the frame, through which the wire protrudes.

An arm 18 is fulcrumed adjacent the shear' 15, in the frame i5, through the medium of oifset trunnions 18 and while separate from the shear 15, is resiliently mounted in constant engagement therewith by means of a spring 88. This arm terminates at its lower'end in a roller 8| positioned to engage a second arm or lever 82 which is pivoted in the frame, a spring 88 serving to maintain a yielding contact between the roller 8| and the lever 82. An additional spring 84 hooked at one end to the framl. l and at the other end to the lever 18 also serves to maintain the parts in a predetermined operation relation.

Mounted onithe side of the mutilated gear 58 is an abutment roller 85, located in such a relation but the peripheryof which gear 58 completes one third of a revoto the axis of the gear and to the end of the lever 82 as to engage the lever at-a predetermined point in the rotary movement of the gear 58, and end thereof as the gear continues its travel. When first engaging the lever 82, the roller 85 will have the effect of swinging the lever against the action of the springs 88 and 84, and arm 18 about its thereby moving the lever or fulcrum with the result that the upper end of the lever 18 will raise the shear, which, by coopera- .tion with the edges of the die opening 11, severs the stock extending therethrough. The timing is such that no severirm' will occur until after the Welding mechanism The welding mechanism of generally a welding head or bracket projecting from the frame in the direction of feed of the wire stock, and an elongated work supporting table therebelow, extending parallel thereto.

The table is formed with a base 88 illustrated herein as,an inverted channel iron to the frame I 5. Any desired form or shape of table may be used, depending on the nature of the work, e. g., with not work, a wider base may be required. Extending along the base 88 are guides 81 for the reception of side rails of a slidable work holding rack 88, these rails being connected across one end.

Removably mounted, 88-88, run along the guides, clamping between them a removable contact strip 80. The contact strip 88 is set slightly below the surfaceof. the electrodes 88 to form with, the upper groove or track for the reception of the measured strip of wire W.

Depending from the base .88 arebrackets 8| for the support of a guide,'rai1 or work stop 82. The brackets 8| are slotted for the reception of an adjusting screw 83 by means of which the rail 82 may be adjusted in' various directions, as desired.

The welding head or bracket comprises a projecting arm or beam 84 secured at one end to the upper part of the frame l5 and braced at its outer end by means of a strut or tie rod 85 secured thereto by an adjustable connection 85, by virtue of which the arm 84 may be adjusted for overhang. A sub-arm 81 is rigidly secured to the arm 84 and also to the frame l5, and serves,

stationary electrodes not only to .reinforce and stiffen the welding head, but to directly support other elements thereof.

An adjustable, slidable bearing block 48, carried by the outer end of the arm 84, serves to support the sprocket shaft 41, this block being actuatable by an adjusting device 48, whereupon the carrier chain 44 may be adjusted as desired. The carrier chain44 is mounted with the upper run thereof passing between the arms 84 and 81, and with the lower run thereof passing between the electrodes 88 and the arm 81.

A pressure bar 88*rests upon the lower run of the chain 44, between the side links thereof, and mounts studs 88 which extend upwardly from the bar. into perforations of the sub-arm 81 servingto guide the bar and maintain it in operating position. Compression springs'HlO encircle the studs of the sub-arm 81, to maintainja pressure between the bar and the lower 'un of the chain at rigidly secured base 88, between the unit E comprises I portions thereof, a

88 between the bar and the lower face illustrated in Figs. 4, 5 and 6, and as shbwn comprises a carriage or housing I03 suitably connected to the carrier chain 44 and fitted with J rollers I04 to ensure even distribution of pressure from the pressure bar 90. Assembled with! in the housing I03 is a removable metal body I00, preferably of copper, insulated from the housing and secured therein by a draw bolt I00. This block is provided with a dove-tail slot to receive a contact shoe I01 which is removably fitted into said slot. The ends of the shoe I01 are bevelled upwardly from an elongatedilat bottom, effective to maintain contact with the work over a'period sufficient to produce a proper weld. A wing I08 integral with the contact shoe extends partially outside of the housing I03 to a point where it may establish contact with spring pressed contact rail or brush bar I00. This brush bar is mounted in guides IIO supported from the welding head'by brackets I I I and suitably insulated therefrom.

The housing I00 also carries a contact spring terminal II2 which is located adjacent to, but normally out of contact with the contact rail I02, the purpose thereof being to make and break a circuit from the rail, through the mov- In order to actuate this spring able electrode. terminal, an elbow H0 is pivoted to the side of the cage and this-elbow terminates in a trigger or shoe Ill of insulating material, designed to engage the work during travel of the movable electrode, and as it crosses raised portions thereof, e. g., the hoops H, the elbow will be forced upwardly into engagement with the contact spring 2, pushing same into contact with the rail I02.

Turn table unit An important adjunct to. the apparatus is found in the turn table unit G, which is used as a temporary'support for work entering and leaving the welding station. This unit comprises a standard Ill swivelled at IIS in/a base II1.

Arms IIO extent T fashion across the top of the standard, as many arms as is necessary being provided, two being illustrated in the herein described embodiment. Guides H0 similar to the guides 01in the welding unit extend along the arms I I0, to receive slidable racks 00.

These racks, as stated above, are formed of a pair of rails connected'across one end and are provided with a series of pairs of upstanding insulated pins I20 for receiving and spacing hoops H, or the like, to which the length of wire'W is to be welded. 5 a

In the usual installation of the. machine, pits I2I may be provided beneath the transversely extending arms H0, for the accommodation of large sized hoops and finished cages, and these pits may be covered over with floor boards I22 when not required.

The wiring diagram is shown in Fig. 5, and comprises a 220 volt input circuit to the motor M, and including a circuit maker and breaker con trolled by push buttons 8. Tapped into this circuit is a volt circuit through a'magnetic circuit breaker, the circuit being completed through the contact rail I02, and; a ground to the machine. The 6'volt welding circuit shown,

is completed through the brush bar I I0! and electrodes 09.

The electric wiring, and usual paraphernalia such as transformers, circuit makers and breakers, and the like are carried by a sub-frame K mounted in the main frame I5, and to which sub-frame are secured conventional insulating conduits, outlet boxes, etc.

,Having thus described my improved apparatus, the'use thereof and method of forming fabricated structures will be readily apparent. A rack 08 on an arm IIO of the turn table, remote from the welding mechanism, may be supplied with a series of preformed hoops H, (which may be formed individually, or by coiling a single length of wire into the form of a spiral) the individual hoops or convolutions of the spiral being placed between the respective pairs of pins I20 to temporarily hold the hoops or convolutions in a predetermined spaced relation. The turn table will then be swung until the filled rack is in alignment with the guides 01 on the work table, whereupon the rack may be transferred tov the work table, beneath the welding head, and locked thereon in any convenient manner, for example by a lock pinl29. As soon as the rack is properly in position beneath the welding head, the machine may be started in operation by pushing the starter button at S, to close the circuit through motor M. The end'of the wire W will of course, have been previously threaded through the straightening rolls of the mechanism C until they are gripped by the feed rolls B.

The motor M will immediately start the driving mechanism of unit A operating, to actuate the wire feed and severing units in synchronism with the carrier chain for the movable electrode. The operations thus far described will be at relatively high speed.

The mutilated gear 58 has just enough teeth to move gear 59 one complete revolution which drives shaft 00. This, in turn, drives gear ll determining the properlength of wire. As soon as this length of wire stock W, has been fed to the work table, the mutilated gear will be in such position as to prevent further feeding of the wire, and the contact shoe I01 will start its lower run.

At this point in the cycle of operations the yoke 24 will shift from high speed to low speed,

through engagement of the shifting lever 20, with the high surface at the side of the teeth on gear 50, and welding of the measured straight length of wire W, to the hoops or spiral H will begin.

As the electrode begins its travel, the contact shoe I01 will ride smoothly across, and in engagement with the hoops H and the insulated shoe or trigger I I4, which has a length permitting it to extend below the hoops will be intermittently raised by abutment against individual hoops "to establish a circuit. The circuit will be established through the spring terminal H2, and the contact strip I02, through the 110 volt line, (Fig. 5) to which the contact strip I02 is connected. A potential transformer I23 is located in this circuit, and has one'leg grounded to the machine. This transformer furnishes sui'flcient current only to operate a lifting or magnetic coil I24, which acts to operate a circuit maker and breaker I20, in the 220 volt circuit. When this occurs, the transformer I26 in that circuit operates to energize the 6'volt welding circuit. connect'ed through a. bus I21 to the brush bar I00,

stop, the potential on the work support.

It will thus be seen that the entire operation of the apparatus is controlled through the single circuit maker and breaker controlled by push buttons 8, all operations, both electrical and mechanical being automatic.

After crossing a hoop, the elbow and trigger under pressure of the spring terminal 2, but pressure will remain on shoe I01 which is influenced by'the pressure bar 98, until just before it reaches the next hoop to be welded. After part of the welding operation has taken place, the roller 85 will actuate As soon as a complete properly welded to all length ofwire has been of the hoops or spiral length comes adjacent to the insulated guide bar 92. During the upper runoi the electrode the draw-rolls are in operation; thus a new wire :is pushed out so that the weldingoperation may be repeated as soon as the electrode has completed claims the movable electrode as its upper travel.

In the meantime the support 8 on the turntable which is remote from the machine is being supplied with hoops. As soon as a cage is completed by the welding of the various longitudinal strips, the rack 88 will be returned to the aligned arm H8, and the tum-table rotated to remove the finished cage and bring a fresh supply of hoops into the welding mechanism.

If found necessary to prevent overheating, any convenient arrangement for water cooling the movable electrode may be utilized. As illustrative a nozzle I30 is located adjacent the end of the welding head, 'in position it begins its operative,

l3| may be posithe waste water. herein described,

lower run movement. A

The method and apparatus are efiective to produce fabricated cages, sheets.

and the like with great rapidity, and acc yet with a minimum of labor, and it will be obvious, that very little modification is required to change from one type of work to another. Hence as limiting. other than as defined in the appended Having thus described ent of the United States is:

1. An apparatus'of the class compris-' ing a frame, a work support projecting therefrom, a welding head extending in substantially paral- 'lel, spaced relationlther eto, an endless carrier chain mounted on said head for movement along said support. an electrode canied by said chain, means to actuate said chain whereby said elecmotor circuit, so

the severing mechanism.

to drip cold water on.

. from, means to feed a the invention, what I a claim as new and desire to secure by Letters Pat- 5 trode will travel from one end'of the work support to the other, and return, and means-to increase the rate of travel of said electrode in one direction and to return the rate of travel to normal in the other direction.

2 An apparatus of theclass described, comprising a frame, a work support projecting therefrom, a welding head extending in substantially parallel spaced relation thereto, electrode driving means mounted on said head for movement along said support, an electrode driven by said means, means to actuate said electrode driving means of the work support to the other, and return, and means to increase the rate of travel of said electrode in one direction and to return the rate of travel to normal in the other direction.

3. An apparatus of the class described, comprising a frame, a work support projecting theresame in welding position, comprising an elevated, extended base electrode defining a work receiving and positioning channel, a welding head extendingin substantially parallel, spaced relation to the work support, an electrode mounted in said head, for movement along the work support, and means to its travel from one end of the work support to the other.

5.v An apparatus of the class described comprising a frame, a work support projecting there- 'stock on the work support.

p ede'termined length, a welding head extending in substantially, parallel spaced relation to said work support: an electrode carried by said head, means to move said electrode along the head in operative welding relation to the length of wire stock on the work support, and detachable means on said electrode to receive and deliver a welding current during its travel from one end of the work support to the other.

.7. An apparatus of immediately adjacent said first work support, means mounting said auxiliary work support for movement relative to said main work supp rt, whereby work on said auxiliary work support may be aligned with said main work support and transferred thereto.

8. An apparatus of the class described, comprising a frame, a main-work support projecting therefrom, welding mechanism associated with said support, an auxiliary work support positioned immediately adjacent said first work support, means mounting said auxiliary work support for movement from its adjacent position onto said main work support, whereby work on said auxil iary work support may be first aligned with said main work support and thereafter transferred to said main work support.

9. An apparatus of theclass described, comprising a frame, a main work support projecting said support, an auxiliary work supporting rack, 'meansmounting said rack for movement from a position 0 a position immediately adjacent said main work remotefrom said main work support to support, and for movement onto said main work support, comprising a rotary turret having a guide slidabiy receiving said rack whereby work may be placed on said'rack, at a point remote from the main work support, moved to a position adjacent said main work support, transferred to said main work support, and thereafter be removed from said main work support in reverse order.

11. A wire fabricating apparatus comprising a frame, work supporting means extending therefrom, means to withdraw wire stock from its source of supply and feed a predetermined length thereof to said work supporting means. said feed means including a mutilated gear, the teeth of which are predetermined in number to accord with the desired length of stock to be fed; a traveling welding electrode effective to operate on said length of wire stock, and means including said gear to vary the rate of travel of said electrode.

12. A wire fabricating apparatus comprising a frame, work supporting means extending there-,

from, means to withdraw wire stock from its source of supply and feed a predetermined length thereof to said work supporting means, said feed means including a mutilated gear, the teeth of which are predetermined in number to accord withthedesiredlengthofstocktobefed, and means acmatable by said gear for severing the the class described, com-- prising a frame, a main work support projecting therefrom, welding mechanism associated with said support, an auxiliary work support positioned porting said predetermined length of stock, a travelling welding electrode effective to operate on said length of wire stock, and means including said gear to vary the rate of travel of said electrode.

. 13. A'wire fabricating apparatus comprising a frame, work supporting means extending there from, welding means associated withsaid work supporting means, means to withdraw wire stock from its source of supply and feed a predeter mined length thereof to said work supporting means, said feed means including a multilated gear, the teeth of which are predetermined in number to accord with the desired length of stock to be fed;, means to. move said welding means along-the work, and to successively produce a series of spot welds, and means including said gear to control the rate of travel of said welding means.

14. Inc. welding apparatus, a movable electrode comprising a housing mounted to travel along the work, a contact shoe removably assembled in said electrode housing, adapted to supp welding currentto the work, and a movable workengaging terminaLon said housing effective to inter mittently establish a circuit through the electrode in accordance with demands of the work, said work engaging terminal being positioned to establish the circuit after engagement of the contact shoe with the work and to break the circuit beforethe pressure is released by said removable contact.

15. The method offabricating metal structures which comprises assembling and supporting a plurality of wires in a predetermined spaced relation, as a unit, positioning said unit of supported wires along an extended welding electrode, feeding an additional length of wire transversely across said unit, and along said extended welding electrode, and severing and welding a predetermined length of said additional wire to each of the supported wires thereby securing said supported wires in unitary relation.

l6..The method of fabricating metal structures which comprises forming a plurality of independent metal hoops, assembling and suphoops in a predetermined spaced relation as a unit, positioning'said unit" of supported hoops along an extended welding electrode, feeding a length of wire transversely across the hoops of said unit, and along said extended welding electrode, and severing and welding a predetermined length of said wire to each of the hoops thereby securing said hoops in their unitary predetermined spaced relation.

17. The method of fabricating metal structures, which comprises forming a plurality of metal coils, arranging and supporting said coils in predetermined spaced relation, positioning said coils along an extended fixed welding electrode, such that each c'oil contacts the electrode, feeding a length of wire transversely across said coils and along said extended welding electrode, and severing and welding a predetermined length of said wire to each of the coils successively and as a continuous operation, thereby securingsaid' be welded.

2,040,349 unit at points of crossing between said prede termined length and said spaced wires, whereby to weld said predetermined length to each of the spaced wires.

19. The method of fabricating metal strucported hoops along an extended welding elec-.

trode, feeding a length of wire transversely across the hoops of said unit, and along said extended welding electrode, then passing a movable electrode along said unit and in contact with said unit at points of crossing between said predetermined length and said spaced hoops, whereby to weld said predetermined length to each of the spaced hoops, and maintain said hoops in their spaced relation.

20. The method of fabricating metal .structures, which comprises forming a plurality of metal coils, arranging and supporting said coils in predetermined spaced relation, positioning said coils along an extended fixed welding electrode, such that each coil contacts the electrode, feeding a length of wire transversely across said coils and along said extended welding electrode, then passing a. movable electrode along said length of wire and in contact with the supported coils whereby to weld said length of wire to each of the supported coils successively and as a contheir predetermined spaced and supported relation.

21.-Anapparatus of the class described, comprisinga. frame, a work support projecting therefrom, an electrode support extending in substantially parallel, spaced relation thereto, an electrode carried by said support, means to move said electrode from one end of its support to the other, in operative contact with work on the work support, and intermittently operating, work engaging means carried by said electrode efiective to close a welding circuit after the electrode has applied pressure to the parts to be welded, andto break the welding circuit before the electrode releases the pressure from the parts to 22. An apparatus of the class described, comprising a frame, a work support projecting therefrom, an'electrode support extending in sub- 7 stantially parallel, spaced relation thereto, an

other, in operative contact with work on the work support, and return, detachable means on said electrode to receive and deliver a welding current during its travel over the work support, and intermittently operating work engaging means carred by said electrode efiective to close a welding circuit after the electrode has applied pressure to the parts to be welded, and to break the welding circuit before the electrode releases the pressure from the parts to be welded.

23. An apparatus of the class described, comprising a frame, a work support projecting therefrom, means on said frame tofeed a strip of metal to said work support, means on said support to guide the strip as it is fed and to hold same in weldng position, a welding'head extending in substantially parallel, spaced relation to the work support, an electrode mounted in said head, for movement along the work support, means to move said; electrode along the head in operative welding relation to the metal strip on the work support, and intermittently operating, work engaging means carried by said electrode and efiective to close a welding circuit after the electrode has applied pressure to the parts to be welded and to break the welding circuit before the electrode releases the pressure from the parts to be welded.

24. In a welding apparatus, a work support. a traveling carrier, a welding electrode secured to said carrier for movement therewith over said work support, and pressure means effective to press the carrier and electrode toward said work support, said electrode having roller means en 7 tinuous operation and to maintain said coils in gageable with said carrier in opposition to said pressure means, effective to hold said electrode against tilting as it engages the work.

25. In a welding apparatus, a worksupport, an endless carrier chain, a welding electrode secured to one run of said chain for movement therewith over said work support, a pressure bar extendingjover a major portion of said run of the chain, on the opposite side thereof from the electrode, and effective to press said chain and electrode toward the work support, said electrode having rollers positioned to engage said chain at a plurality of points, in opposition to said pressure bar, whereby to hold the electrode against tilting as it engages the work and in a position j parallel to the work support as it .travels over the work.

26. The method of fabricating metal structures,

which comprises forming a plurality of metal coils, arranging and supporting said coilsinpredetermined spaced relation, positioning said coils' along an extended, fixed welding electrode, feeding a length of wire beneath said coils and along said extended welding electrode, and severing and welding a predetermined length of said wire to each of the'coils successively andas a continuous operation, thereby securing said hoops in r their predetermined spacedrelation.

' ALBERT G. WAGNER.

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