[1]Patented tOeQ 10, 1029 lp 38t573 UNITED STATES PATENT OFFICE' ELVIN S. GOODSPEED, OF DETROIT, XI CHIGAN, ASSIGNOR TO GENERAI@ XOTORS C03&-, PORATION, OF DETROIT, MICHIGAlq, A CORPOR&TION OF DELAWARE ARC WELDING Application :Rled Tuly. 22, 1920. Serial No. 398,198. The invention relates to methods and apparatus designed to utilize variations in eleetiical conditions, such as resistance and voltage, to produce operation of mechanical controlling or feeding device. One of the uses to which the invention is applicable and in connection with which it is believed to have especial utility, is for the control of feeding mechanism -for electrodes of apparatus in 10 wliieh an electric are is em]ployed for heating or welding purposes, and more particula.rly apparatus of the type in which a inetallie electrode is employed, although it will be clear that in its broader aspects the invenjr, tion is not -limited to use in such apparatus. In arc weldin- or lieating apparatus, and especially where a met,,tllic electrode is employed, the electrode wastes away or fuses as the work proceeds, ahd it is necessary to 20 provide for the feeding of the electrode toward the work, either by hand or by appro-, riate automatic mechanism. Means htve teen devised in which-ihe electrode is supplied ,it a constant rate, but inasmuch as the 2r, fusion or dissipation of the eloetrode is affected by several variable factors a constant feeding movement of the electrode has not proi,ed practicable. Efforts have also been made to provide for automatic feecl in re3 ' spo-iise to varying conclitions in the are itself@ biit in general the difficulties of auton-latic feeding have been such that it has been the usual practice to secure the electrode in a ha-kid operated support or holder in 35 order to place the feeding of the electrode under the direct control of tl@e operator. Work of this character bowever is tedious and reqiiires -,t high degree of skill and moreover is likely to prove injuriou,,w to the eyes of 40 t@e workrnen. The priiiiary object of rny invention is to provido- means whereby the movement of an el.ement, such as an electrode holder or ot-lier -device, may be rendered responsive to vary45 in- electric conditions such as those occurrin"(r in an electric are. A further object of my invention is to provide automatic mean8 for controllinotile movement of an electric or like movable ele50 ment whereby the neces'sity for close attention of the operator to the work may be eliminated and a greatly increased rate of production may be attained, thereby materiary les- - sening the expense of the product. A further object is to pr@ovide an automatic feeding de- 55 vice in which the rate at which electrode material is supplied shan be dependent upon the conditions existing withiia the are itself, and whereby a uniform length of are may b6 maintained. A further object is to provi --e a 60 feedindevice whicli shall be capable of retrdctitig an electrode in proportion with the - shorteninof the are, thereby enablin- welding operations to be performect., ui@on the work of uneven or irre,-Ular contour. Anotlier object is to provide a feedin- device combinina an automatic control of @he eleetr6de with a means enabling the operator to give at will any desired adjustment or position to the electrode holder. With the above 70 and other objects in view as will appear more. fully from the followincy description my inveiition comprises the features of novel'Ly hereinafter set forth and recited in the appended claims. 75 In the accompanyino, drawin(ys illustrating some emboaiments of -my invention: Fi-. 1 is a view in 'elevation of an electric weld@ing apparatus adapted to employ the principles of my in'velation. 80 Fig. 2 is a sectional view taken on line 2-2 of Fig. 3, showing in detail one form of electrode feeding device. , Fig. 3 is a sectional view on line 3-3 of Fi-. 2. 86 Fi-. 4 is. a side elevation of a second embodin-ient of my invention. Fig. 5 is an end elevation, partly in section, of the feeding mechanisiii of Fig. 4. Fig. 6 is a side elevation on a larger scale oo 'and partly in section .9howing the feeding mechanism of Fig. 4. Fig. 7 is a sectional elevation on line 7-7 of Fig. 5., Fig. 8 is a diaorammatic vic,,v Rhowing elee- 95 trical connectic@ns for th(,, ctutches of Fi 7 9. Fig..9 isa similar view showing a riAc,-Iified fotm of wirine, diagram. Fig.10isaviewshowingaflexibleele6trode contacting device which may be,-.mployed in ioo
[2]2 1,738,573 any of the forms of feecl mechanisms shown. Pi-. 11 is a plan and Fig. 12 a side elevation ' partly in section, of a hand-operated holder connected to an automatic feed device so as to combine to some extent the advantages of both hand and automatic control. Referring to the drawings 10 indicates a pedestal upon which is supported a frame 11, adapted to carry a rotatin- table 12 upon 10 which a work piece 13 may l@e mounted. The work piece may be of any desired character, but is illustrated in this case as being an axle housing of a common form. The work table 12 may be rotated at the desired speed by 15 meansof a belt 14 operatina upon the pulley 15 a-nd driven by the stepped pulley 16, the latter being rotated by lny suitable form of gearinl, which may be mounted - within, the housii@g 17, and driven by motor 18 through 2o flexible connection 19. Any suitable means of a@justin- the support @@ the motor and 20. It will be the particular pass under the 25 y part of my inventio-n and that any de ired or suitable means of causing the relative movement of the worl- and the electrode holding device may be employed. 30 The standard 21 which may be carried by the pedestal 10 is adapted to support a swinging arm 22 to which may be pi-@otally connected, as at 23, the housing 24 which witli its related parts constitutes the welding head. 35 A brac'ket 25 may be prov-,ded to support the welding head and permit its movement about the pivot 23 and around the axis of the standard 21. The welding head will, of course, be so supported that the metallic electrode 26 40 may be properly positioned above the point on the work 13 where the welding operation is to be performed. The h6usin(r of the welding head includes the lug 27 fo@ attachment to the pivot 23, and an extensi6n 28 within which 45 ma-y be supported any desired type 6f constant speed motor, as'the electric motor 29. The shaft 30 of this motor cai-ries on one end the worm 31 enga(ring with worm wheel 32 supported by the shaft 33 ---uitably mounted in 5o bearings in the walls of housing 24. Atotion is communicated from shaft 33 through clutch members 34,35,'to Lyea,r 36 in mesh -with gear 37 loosely mount@ed @pon shaft 38. Motion is also communicated from shaft 33 55 through gears 39, 40, to gear 41 suita;bly supporte on bearings 42' thereby driviiig gear 41 in a direction opposite to the direction of rotation of gear 37. The gear 37 is adapted t6 drive shaft 38 by means 6f the friction 60 clutch 42 which may be subjected to the desired pressure by means of spring 43 adjustable by screw 44. The (,rear 41 is also adapte(i to drive shaft 38 by rneans of fricti,on clutch 45, which latter. is a('.just-(l by 65 means of rod 46 engagin- with the adjusting screw 47 carried by the lever 48. Mounted upon the.shaft 38 'and seciired thereto is the grooved feed wheel 49 adapted t6 engage with. a body of electrode material, shown at 26. This material is shown in the form of a cylindrical rod or bar, but it will be understood that it may take the form of a, strip or wire as desired, and that it may be supplied in quantity from a reel or roll in order that the inconvenience and waste due to the use of 'short lengths may be avoided. The lever 48 is piv6tally attached at one end, as at 49', to a. part of the hoiising 24; the other end is coinnected in any suitable manner, but preferably by the compound linkage com- 8 prising link 50, lever 51 and link 52, to the core 53 of a solenoid 54. This solenoid may be of usual type but is shown as comprising an adjustable plug or stop 54' which serves to limit the movement of core 53 and to in- 8 crease the magnetic attraction as the coreapp;roaches ifs limit of movement. The clutches 42 and 45 may be of any desiredconstruction of friction clutch but I prefer clutebes as shown of the multiple disk type, -9 beca,iise of the uniform torque transmitted as well as the capability for accurate adjustment. By reference to the structure thus far described it will be seen that-the clutch 42 will 9 tend to drive the feed wheel 49 at a constant rate inone direction which direction is takbn to be that which would retract the electrode from the work. The clutch 45 on the other hand will tend to drive the feed wheel 49 in i the opposite direction, that is, in the direction to feed -the electrode 26 toward the work. The resultant effect upon the direction of travel of the electrode will therefore depend upon the relative driving torque exerted by the said clutches. The effect of clutch .42 may be determined by the adjustment of -screw 44 as above pointed out. The effect of clutch 45 is determined by the position of lever 48 which is varied b@ the ma-netic attraction due to the current flowii@g in tbe winding 6f soleiaoid 54. Bv reference to Fig. 1, it will be seen t-l-iat one terminal 55 of the main line by wbich the welding current is supplied is grounded upon the work-supporting frame 11 and the other terminal 56 is connected to the welding head 24, these parts of course being suitably insultted from each other in order that the welding, current may be caused to pass be- i tween the work and the electrode 26. The wire of solenoid 54 is grounded at one end upon the weldinz head 24 and is connected at the other end by-a conductor 57 to the frame 11 or to som@ otber suitable point of communication with the main line terminal 55. It will- be seen, therefore, that the solenoid 54 is arranged in shunt with the are aDd hence as the'resistance of the are increases or as the' voltage builds up therein a greater quantity
[3]of ourrent wiU flow through the solenoid 54 and thereby t-he clutch 45 will be operated to cause the feeding of the electrode 26 in the direction of the work. The clutch member 34 is arranged to be thrown into engageinent with the co-operatiiig clutch member 35 by a lever 58 which iiiay be actuated in one direction by a spring 59 and in the other by magnetic attraction of the electro-manet 60. This electro-magnet 60 may be arranged in any suitable circuit independent of the welding circuit as, for exaniple, an ordinary 110-volt li-htine, eircuit- 61. The supp@v of current from the. main line 55, 56, will be regulated by the use of any -of the electric welding sets or control panels now on the market preferably by one of the type d@signed to supply a current of approximately constant amperage. In the 20 wiriiig of the sets used in are welding it is customary to control the main switches by means of a control circuit extending to some point adjacent. to the position of the operator. A control circuit of this kind is indicated at 2,5 62. A double. switch 63 mounted. in any suitable position convenient. for ihe operator is adapted to close both of the circuits 61, 62. This switeb is preferably so constructed that the circuit 62 will be broken at contact 64 so slightly before the breaking bf the circuit 61 at contact -65. The result of this arrangement is that the clutch 42 is permitted to operate for a very short tirne o@fter the breakiiig of the main weldino, circuit thereby caus'ino, the electrode 26 to Se withdrawn slightlv '7' '3 thus drawiiig the are. As the resistance of the are increases the current through the shunt circuit will be proportionately increas'ed until the effect -of the solenoid upon clutqh 45 becomes sufficient to overcome the 7:) action of @lutch 42 and cause the electrode material to be fed toward the Work. By proper adjustme nt of the two clutches the mechanism may be made to feed the material to or from the work at such rate as to maintain 75 an are of substantially unfform lengtli. Further more, if the are sliould approa6h an elevated portion of the work, as a flang@.or other irregularity, the resultant shortemng of th6 arc will cause the lifting of the elee- ro tro'de material, whereby the are may be maintained even in the presenoe of considerable irregula rity in the contour of ihe work. In th-e , lorm of the invention shawn in Fi-s. 4 to 7 inclu ive, 80 is a pedestal suppc@rtgk 85 a standard 81 to which i,-@ clamped a bracket82. Am arm 83, pivotally secured to bracket 82, serves to support pivotally the motor 84. It will, be noted that this supporting means provide s a wide rang,- of adjiistment a:s. to 90 height and angular position. Upon the motor is carried a suitable bracket 85 to'support a reel 86 for the electrode material 87. The feeding device in this instance i housed within a caising secured to th6 frame 95 of the motor 84, and comprising a cylindrie'al pdrtion 88, an upper section 89 and a side portion 90. Mounted in suitable bearings in thle h 88 is the sl@aft 91, adapted to be ousill@b driven y the shaft of the motor as by a 1(0 fromtlieworli:andtherebypreventing"free@-.splined,6,onnection. Surroui@dingthisshaft ing" to the work. The feeding of the electrodo is facilitated by the use of a pressure roller 66 which may 4o be supported upon a pivoted a.rm 67 yieldinglv forced against the electrode by spring, 68 a@djiistable by means of screw 69. dditional guide rollers 70, 71 may be provided, the latter of which is shown as being sup45 ported upon a slidable plate 72 under the influence of spring 'i3. The shaft 38 may be supported in stiitable anti-friction bearings 74, 75, in order to avoid external resistances tending ito affect its sensitiveness to control by the devices above described. In the operation of this form of my invention, the motor 29 will be first started and the mechanisrn for causing relative movement of the work and the welding head will be set in operation, the electrode 26 being permitted to coine into contact with the work. Then upon closing the double switch 63 the clutch members 34, 35, will be e . nga-ed and the, welding 60 current caused to flow through the work and the electrode. Since there is only slight resistance at the-point of contact of the electrode with the work there will be a relatively small etirrent flowing through the shunt cir65 cuit 54, 57, and the clutch member 42 will be permitted to operate to retract the electrocle are the two magnetic clutche@S 0 ,., 93, the,@viiidat'8'@e end respeethe other gs, which 1,)5 to rotate therewith. The clutch disks 96 and 97, which are adapted to be influenced by the magnets in the clutch casings and thereby caused to rotate wit4 the shaft, are rioidly connected 110 respectively to pinions 98, 99. Both of these oears mesh with gear 100 secured to rotate ;ith the shaft 101, journalled in the support 89' suitably mounted in the casinly section 89. It will be evident from the arr@ngement of 115 parts above described that the pinions 98. 99, cannot both rotate in the same direction, and that the pinion upon whose clutch disk the @ieater, a etic attraction is being exerted m gn 120 op rate to turn the gear 100 thereby rotating the shaft 101 in one or the other direction depending upon the relative strength of current flowing in the coils of the res ective el.utches, or, @hould both clutches be mo- 125 mentarily of the same strength,.permitting the shaft to remain at re9t. Motion imparted to the shaft 101 is transmitted through the worm 102 'to the w6rm wheel 103 secured to the shaft 104. The latter extencls through bearings in the sides of
[4]4 1,738 the casing and into the casing section 90 which is separate from the casing 88 but secured in fix6d relation thereto. Upon the end of shaft 104 inside of casing section 90 is the feed roll 105 between ivhich and pressure roll 106 the electrode wire or strip is caused to pass. Additional guide rollers 107, 108, are mounted in the lower end of casing 90, and 10 springs 109, 110, enaaged by screivs 111, il2, operate to force rolrers 106, 108, respectively, against C07operatino, rollers 105, 107, the rofiers 106, 108, bein@ mounted upon pivoted ai-ms eno-aged by the sprii@gs as shown in 15 Fig. 6. The casing section 90, whic@ is provided with a dooi- 90' to give convenient access thereto, is made separate from and merely attached to the exterior of the casing in which 20 the di@iving niechanism and o-ear@ are located zn in order to prevent access of oil or the like to the feed devices and the electrode inaterial. In this el-iibodinient of the invention the shaft upon which the clutches are located 25 rotates at relatively high speed, the speed reductioii devices beiro- located between the clutch mechanism and the feed rolls. As a result irregularities in the operation of the clutches will be reduced to a degree correso spoiiding to the speed reduction and the feed may be i,endered more uniform and freer from fluettlations. In this form of the device the clutch ivhich operates to feed the electrode in a direction 35.away froi-n the work n-iay be coniiectefl with a source of constant current as by the conductor 115, Fig. 8, whereby the action of tlio clutch members ivill remain uniform or of a predeterinined value. The other clutch may 40 be coiinected iii shunt with the are, in a mqnner siiililar to that already described in connection %vith the form of Figs. 1-3 ' as at 116. Fig. 8, -wherebv as the resi.stance in the arc'inereases, due t@ the increase in the dis45 tance between the electrode and the work, the magnetic strength of the clutch 95 is increased sufficiently to overcome the action of the other clutch 94 and feed the electrode toward the work. Any convenient control 50 devices, sucli as rheost,.tt 117 and switch 118, similar to s;viteli 63, Fig. 1, may be provided in oi-cfer to re-ulate or adjust the flow of current throu-Ii the two clutches. Aiiotlier arrangenient of.'wirin- is sho--wn .55 in Fig. 9. In this arrangement the clutch 95 is I)Iaced, as in the form previousl@ desci-ibed. in s4-Lint witli the are, the rhe'ostat ll'T beina employed if desired, but no hand ppoi-atedsivitchbein--necessai-y. Theclutch c-o 94 is I)Iace(i in series -with the are@prefer-Liit 119 arran(yed in shunt witli ably in a eire t, the iiiain line with a variable resistance 120 so th,,it a predetermined port;on of the ctirreiit on the main line will flow thro-Ligh the o5 magnets of the clutch. With this arrange573 ment it will be seen that when the main switch is ellosed the clutches will at once become operative to feed the electrode material upwardly or do-wn-wardly as may be necessary to obtain and maintain the balance of predetermiiied conditions in the respective circuits. Furthermore the mechanism is rendei-ed especially sensitive siiiee the clutches vary inversely, that is, as the flo-w througli clutch 95 increases diie, to a lenothening are that through clutch 94 decreases due to a reduced flow in the main line. while as the flow throu(rh clutch 95 decrease's that tlirough clutch 94 increases. It will be understood, further that the arr-,tngement of control circuits above described is also applicable to other forms of tra-usmission or electrode drivin- mea:ns. The use of a ree I of electrode material is greatly facilitated if the feed devices be adapted to feed the material in a curyed condition just as it comes from the reel, thus avoidino, the necessity for straightening the wireor-strip'. Itwillbe understoodthatthe sensitiveness aiid accuracy of control of the automatic devices would be seriously affected if they were to be -iven sufficient stren,-th and rigidity to strai (rllten as well as feed the w-ire, and at the same time it is impracticable to eiiiploy independent positive straightenin(r clevices owing to the difficulty, of synchronizino- the operation of t@e straighteniiag device witli that of the feeding device. I have therefore so arrang@ed the feedin- device that it stipplies the wire in the curved condition in i which it unwinds from the reel, as shown in Figs. 4 and 6, and I believe that I am the first to propose the us.e of the curved electrode. In order to provide for the feeding of the curved -wire or strip I mount the guidin(r devices in stich rel@,ttive positioiis. that lie in a curve-J rather than a straicht A single pair of -uides, as for ex@mple the pair formed by the upper and lower feed rolls of Fi(Y 6, are adapted to receive eithbr a curved or a straight electrode. A sti-aight electrode is shown in broken lines in siid figure, whereas a curvecl electrode is shown in full lines. I prefei, however, to employ another' giiiae device, including a support 113 enel6sin- a spool or sleeve 114 of refractory material and adjustably secured to the casing 90, as b screws 113' passing through slots in the support. The position of the support is thus rendered adjustable to i accoinniodate it to the curvat-Lire of the wire. It will be 'understood that various other transmission devices mav be employed embodyina the principles ol my invention, and providing means whereby a plurality of I sources of relatively v ari@ble driving influence may be so combined as to impart to the element to be moved the resultant of sueb influeiiees, and therefore I do not wish to be limited to the forms above described.
[5]1,788,578 5 In order to increase the efficienc'y of transmission of current I have devised the novel form of feed device shown in Fig. 10. In this device the feed rouers 140, 141, one at least of which will be arranged to be automaticauy driv6n as already described, instead of contacting with th6 electrode material, are adapted to drive traveling flexible contactirig and gripping elements@ guch 10 as chains 142, 143, between which the electrode 144 is positioned. The chains will be supported by additional rouers 145, 146, or equivalent means. The links wiU. be prefer'ably so formed and codnected as to permit 15 deflection from a right line in one direction only so that the contact links 147, which may be appropriately fornied to fit and gtip the ele'etrode material 144 may, forcibly engaoe 1 .the said mate'rial and provide an'extended ,to conducting and gripping surface. I It will e seen that this form of feed d(,,vice a:ffords an increased contacting surface and thereby insures sufficient conducting area at all times to proveiit ahy disturbing in25 fluence due to. the po8sible occurrence of nonconducting' spots occasioned by the prcsence of oil or the Ue on the rollers or the electrode material. In Figs. 11 and 12 1 have shown a iaovel so form of combined hand-operated and automatic feed device including a casing 150 provided with a handle 151. Witliin the casing is a feed roller or other feed device 152 mounted upon shaft 153 connected by flex35 ible or universal joints 154, 155, and telescopic shaft section 156 to a shaft; - 157 arranged to be driven by one of the. forms of automatic devices hereinbefore described and which is indicated generically at 158. Am ad&o justable spr,ing pressed pressure roller- 159 may be @rranged to co-operate with the driving device 152, and additional g@uid[e iollers 160, 161, one of which'@iay be spring-pressed, as shown, may be employed to provide con45 tact a-nd driving engagement with -the electrode material 162. & suitable conductor - 163 is ari-anged to convey a current to the feed,rollers in any usual or desired ihanner, and a control circuit is connected to con5o ductors 164, which conductors are connected to a switch 165 adapted to beactuated by I a trigger 166. It wiR be noted that the- han4-supported electrode holder is adapted to have consider55 able freedom of movement, owing to the provision. of the joined and telescopic coniiection to the automatic driving device thus permitting the operator to position - the elee-@ trode with reference to the work and to move 60 it al@out as the Welding operatioii prooresses. The hand @6ntrol thus affords a sort of- rough attention and the highest degree of skffl, namely, the maintainance of the proper length of are. This device-wiu be of especial advantage in welding or analogous operations where the contour of t.he work is To of considera-ble irregularity or the required movement of the electrode is such as not to be readily produced by mechanical means only. It will be noted that I have provided an automatic f@ed wherein are embodied two constantly acting feed devices adapted to apthe electrode masistance in the ar or the voltage iequired therein. the electrode therefore results from the combination of two forces which @aay be ad- 85 justed to maintain a very aceiirate balance when the are is of normal leiagth. Furthermore the device is very sensitive to variations inasmuch as both- diiving mechani@ms are constantly in motion and the parts af- go fected by the variations and the speed or direction of which is subject to change are relatively small and light and their inertia is correspon diiagly small. While I have set forth herein in detail 95 certain forms of embodiment of my invention it will be understood that many changes in details of construction may be made *ithgut departing from the spirit and scope of the InventiOn . 100 I
