2,191,494. Feb. 27, E. F. NELSON STUD WELDER. 2 Sheets-Sheet. Filed July 5, l938 3 SSNNN. <22zz ZZZZZ 477OARAVA

Transcription

1 Feb. 27, 19. E. F. NELSN STUD WELDER Filed July, l938 2 Sheet-Sheet?Y 3 SSNNN 2 <22zz ZZZZZ 477ARAVA

2 Feb. 27, 19 E. F. NELSN STUD WELDER Filed July, Sheet-Sheet 2

3 Patented Feb. 27, 19 2 S UNITED STATES STUD WELDER 11 Claim. Thi invention relate to mechanim for elec tric welding. It i an object of the invention to provide in proved portable apparatu for electrically butt Welding Stud or other rod-like member to the Surface of metallic object. Another object of the invention i to provide, in apparatu of the cla decribed, mean for elec trically timing the preheating of the part to be joined o that all weld will be uniformly alike. A further object of the invention i to provide, in apparatu of the above-mentioned type, mean for Variably lengthening or hortening the opera tive cycle of the apparatu. The invention poee other object and fea ture of advantage ome of which, together with the foregoing, Will be pecifically et forth in the detailed decription of the invention hereunto annexed. It i to be undertood that the inven tion i not to be limited to the pecific form there f herein hown and decribed a variou other embodiment thereof may be employed within the Scope of the appended claim. 8 Referring to the drawing: Figure 1 i a vertical ectional view taken in a plane paing medially and longitudinally through one form f my tudi Welder. Figure 2 i a tranvere vertical ectional view of the tructure illutrated in Figure 1, the plane of ection being indicated by the line 2-2 of the latter figure. Figure 3 i an end elevational view of the ap paratu hown in Figure 1. A portion of the view i mitted to conerve Space in the drawing. Figure 4 i a longitudinal vertical Sectional view of a tudi welder embodying the preferred form of ny invention. The part of the mecha nim are hown in the poition that they occupy jut prior to the actual welding of a tud to the Surface of a metallic object. Figure i a tranvere vertical Sectional view of the tructure hown in Figure 4. The plane of Section i illutrated by the line - of the latter figure. Electric butt-welding of tud, or other rod-like member, to the Surface of metallic object ha long been practiced in indutry. Thi procedure ha generally been accomplihed by hand; the tud uually being held in a uitable holder which form one terminal of the welding circuit, and the other object to which the tud i to be bonded forming the other terminal. The Welder, graping the holder in hi hand, contact the charged tud and the object urface drawing the tud away from the urface o a to create an arc. PATENT FFICE Edward F. Nelon, Wallejo, Calif. Application July, 1938, Serial No. 217,34 (C ) In a hort time the metal of the object in the arc Crater and the end of the tud will have increaed in temperature to the melting point whereupon the welder quickly plunge the tud end into the arc crater, the current i turned off, and the molten metal i allowed to cool and olidify. The Stud, which i now bonded to the urface of the object, may then be eparated from the holder. There are everal undeirable feature con nected with thi hand method of welding. Firt, it i left entirely to the dicretion of the operator to determine when the repective metal of the Stud and the object to which the tud i to be bonded, have reached the proper welding tem perature. In a great many intance the metal are joined before they are in a molten tate, thereby reulting in a faulty and eaily broken Weld. Secondly, even though the metal happen to be brought to the correct temperature, the tudi may be plunged againt the object urface lightly to ne ide of the arc crater thereby alo reulting in a weld which doe not form a proper homoge neou bond between the tud and the object. In the third intance, the length of the arc gap may vary with each weld which caue the metal to heat up fater or lower a the cae may be, there by producing Weld of non-uniform trength; and, finally, but few of the tud Will be found to be truly perpendicular to the urface of the object. Thu, unle exceive clearance i al lowed in pre-drilled hole in planking or other article to be attached by the tud, coniderable difficulty will be experienced in readily fitting thee part together. Workmen encountering an inclined tud uually bring it into perpendicular poition with the aid of everal blow from a heavy hammer. Thi i a dangerou procedure ince it i likely to fracture and eriouly Weaken the weld. I have provided apparatu by mean of which all of thee defect are remedied, which will permit the placing of Stud or the like a rapidly a they have heretofore been placed by hand, and which will inure that each weld i poeed of a maximum of Strength. In detail, and referring to Figure 4 of the draw ing, the preferred form of my invention con prie a cat iron casing 6 having a plurality, preferably three, of radially extending ear each being bored to lidably receive a tubular leg 8. Each of the leg 8, at it dital end, i inter nally threaded to receive the threaded hank of a foot 9 whoe pointed end f i adapted to bear againt the urface of a metallic member 2 to which the tud 3 i to be welded. Nut 4, which clamp the lotted end of the leg 8 about the i

4 feet 9, Serve to lock the latter once they have been adjuted to a deired poition; and et crew 6 in each ear 7 erve to clamp the leg in the ear and provide for extenion and retraction of the leg a deired o that the pacing between the caing 6 and the urface of the member 2 may be varied. Mean i provided for upporting the tud 3 to be welded to the member 2 for movement per pendicularly toward and from the urface of the member. Dipoed centrally between the three paced leg 8 i a tubular chuck f, one end of which i provided with tranvere lot 8 to form a plurality of finger 9 which frictionally engage the tud 3, and the other end of which i pro vided with a threaded bore 2 for receiving the threaded Shank 22 of a cap 23. Thi connection i provided, primarily, o a to permit the mount ing of chuck adapted to Support tud of dif ferent diameter. The cap 23 i provided with a flange 24 having therein a plurality of aperture in which are inerted inulating buhing 26 through which crew 27 pa o a to attach the cap to a flange 28 formed at one end of a tubular ran 29 which i lidably mounted for axial nove ment in the end of a non-ferrou tube 3. An inulating - waher 32, interpoed between the flange 24 and 28, erve, in conjunction with the buhing 26, to electrically inulate the tud 3 from the ram. 29. Since the ran i lidable axially of the tube, the tud f3, during Such nove ment of the ram, will be moved away from and into paced relation wtih the urface of the mem ber 2. To limit thi movement of the tud o that the gap between the end thereof and the urface of the member 2 will be held at approxi mately one-fourth of an inch, a collar 33 i pro vided on the ram which impinge againt the end of the tube 3. Electro-magnetic mean i provided for effect ing movement of the ram in the tube 3. Secured in the oppoite end of the tube in any Suitable manner, uch a by mean of the pin 34, i an iron pole-piece 36 which i centrally bored to lidably journal a rod 37, the latter extending concentrically along the tube. The Irod 37, adja cent the pole-piece, i houldered and againt thi houlder abut one end of an iron armature 38 which i lidable, with the rod, in the tube 3. The oppoite end of the armature i reduced in diameter to provide an abutment 39 which may trike againt the end of a crew 4 threaded through the caing 6 and projecting into the bore of the tube 3, o a to limit movement of the armature in one direction. A waher 42, which lie againt the end of the armature, i provided on the rod, a i alo a ferrule 43 which, at one end contact the waher 42, and at the other end terminate adjacent the end of the rod, and pae lidably through an aperture formed in the end wall 44 of the ram. 29. A nut 46, threaded on the end of the rod 37, Serve to clamp the armature 38, the waher 42 and the ferrule 43 together a a unit on the rod o that all may move together with the latter. A coil pring 47 urround the ferrule and i inter poed between the end wall 44 of the ram and a flange 48 formed at the end of the ferrule adja cent the nut 46. Surrounding the end of the tube 3, in which the polepiece 36 i poitioned, i an actuating coil 49 encloed by a ferrou hell and end plate 2 and 3; and a ferrou houing 4, threaded onto the end of the tube 3f, and con tacting the pole-piece 36, erve to clamp the end plate againt the hell and the end plate 3 againt a Suitable houlder therefor provided n the caing 6. A magnetic circuit i thu pro vided, through which flux may flow when the coil 49 i excited, compriing the pole-piece 36, the houing 4, the end plate 2, the hell, the end plate 3, the caing 6, and the armature. 38. Surrounding the houing 4 i a plit leeve 6 having a pair of apertured ear 7 riing there from through which pae a bolt 8 by mean of which the leeve may be clamped, immovably, to the houing. Formed integrally with and ex tending radially from the leeve 6 i a hollow handle 9 provided with an aperture 6 in which i inerted a puhbutton witch 62, and with a tubular Spout-like projection 63. A pair of cable 64 and 66 enter the extreme end of the handle, through Suitable aperture provided therein, the former of which contain three conductor 67, a pair of which are connected with the repective terminal of the puh-button witch 62 and an other of which i connected with one end of the actuating coil 49. An additional conductor 68 connect the other end of the coil 49 with one of the terminal of the witch 62. The conductor 66 i brought out of the handle through the tubu lar projection 63, i provided with a loop 69 o a to inure ready flexing of the conductor and is Connected to a connector lug 7 which i e Cured on the Shank 22 by preure of the chuck body. The end of the handle 9 i provided With a SaW lot paing tranverely through the entrance aperture of the cable 64 and 66, and a bolt 72, which pae through apertured ear 73 formed at the end of the handle, erve to clamp the cable immovably in the handle. The normal poition of the ram 29 and the tud 3, jut prior to the welding of the tud to the Surface of the member 2, i a hown in Figure 1 wherein the end of the tud ret on the Surface of the member and the collar 33 of the ram, in Figure 4, i paced about one-fourth of an inch to the right of the end of the tube 3. After poitioning the apparatu, o that the Stud i located over the pot om the member 2 to which it i to be welded and all of the feet are reting againt the urface of the member So a to inure perpendicularity of the tud, the operator depree the puhbutton witch 62. Thi caue a flow of current through the actu ating coil 49 and imultaneouly cloe a control relay or circuit breaker on the welding current generator, not hown, which intitute a flow of current in the cable 66. Thi heavy welding current pae through the tud 3, the member 2, and back to the generator by mean of a cable, not hown, which connect the member 2 and the generator. A oon a the actuating coil 49 become energized, the flux created in the magnetic circuit thereof will attract the armature 38 toward the pole-piece 36. Thi will, through the connection between the rod 37 and the ram 29, move the ram and the tud away from the Surface of the member 2. A oon a the con tact between the end of the tud and the urface of the member 2 i broken, an arc will be truck therebetween which will rapidly raie the ten perature of the end of the tud and that area of the member in the arc crater T4 to the melting point. The ram and the Stud will, under the pull of the moving armature 38, continue to move away from the member 2 until the collar 33 of the ram impinge againt the end of the tube. 60

5 4 SS 76 3 whereupon further movement of the ram and tud will ceae. Mean i provided, operative after the arc between the tud and the member 2 ha been etablihed for an interval of time, for quickly plunging the molten end of the tud into the arc crater created in the urface of the member. Formed in the caing 6 i a rece 76 in which, and lidable along the tube 3, i a plunger 77 having thereon a flange 18 and between the flange and the bottom of the rece i interpoed a relatively heavy coil pring 79. The pring 79 tend to project the plunger outwardly from the rece toward the end of the tube 3f. Hinged, by a pivot pin 8 upported by lug 82 provided on the exterior of the caing 6, i a latch trigger 83, the pawl 84 of which engage a urface of the plunger fange 78. The latch trigger ha connected thereto, by a pivot pin 86, one end of a connecting rod 87, the other end of the latter being pivotally joined by mean of a pivot pin 88 with an end of a lever 89 which i mounted, by a pivot pin 9, on the end plate 3. A torion pring 92, engaging at it repective end the end plate 3 and the lever 89, tend to flex the articulated member, formed by the lever and the connecting rod 87, upwardly to ward the axi of the plunger. A trip lever 93, which i pivotally mounted on the caing 6 by mean of a pivot pin 94, i provided with an arm 96, which extend into the bore of the tube 3 through allined aperture 97 formed in the tube and the caing 6, and with a relatively horter arm 98 which ret on the upper ide edge of the lever 89. The arrangement of the part i Such that when one ide of the arm 96 of the trip lever 93 i in it normal poition, engaging the top therefor provided by one ide of the aperture 97, the articulated link formed by the lever 89 and the connecting rod 87 will be retrained, due to being in engagement with the end of the trip lever arm 98, from fiexing upwardly beyond a traight line paing through each of the pivot pin 86, 88 and 9. Thu the latch trigger 83 may not wing about it pivot pin 8 while the link i on dead center and conequently the trigger pawl 84, ince it engage the plunger flange 78, will maintain the plunger retracted and the pring 79 under con preion. After the arc between the tud 3 and the mem ber 2 ha been truck, a wa explained above, the ram 29 move until it contact the end of the tube 3 whereupon it top. The armature 38, however, continue to move toward the pole-piece 36, compreing the pring 47 in o doing, and advancing the waher 42 along the tube 3 toward the projecting end of the trip lever arm 96. When the waher contact the end of the arm, continued movement of the armature will caue the trip lever to wing about the axi of it pivot pin 94 thereby cauing the end of the arm, 98 to flex the articulated link downwardly. A oon a the axi of the intermediate pivot pin 88 pae ut of planar a linement with the axe of the pivot pin 86 and 9, the force exerted on the latch lever 83 by the compreed pring 79 will caue the latter lever, ince it i no longer re trained from movement by the articulated link, to wing downwardly thereby releaing the plunger and allowing the pring 79 to uddenly project the plunger and the ram 29, which i connected to the plunger by mean of a tubular extenion 99 of the plunger, toward the member 2 thereby plunging the molten end of the tud into the molten metal of arc crater 74. The perator now releae the puhbutton 62 to hut of the welding current and the current flowing in the actuating coil 49 and pull the apparatu utwardly away from the member 2 o a to trip the chuck 7 from the tud. Mean i provided for variably regulating the extent of the interval of time between etablih ment of the welding arc and the releae of the mechanim to plunge the tud into the arc crater So that the latter tep may be made to ocur exactly at the intant that the two metal to be joined have reached the correct temperature. In the houing 4 are provided a pair of parallel bore of and fo2, the former of which i ron centric with the houing axi, and a portion of the houing i hollowed out to provide a chamber 03. Aperture 4 provide communication be tween the chamber and the bore l. The bore 0 act a a dahpot cylinder and the end of the rod 3 extend thereinto to erve a a piton, while the bore 2 i provided with a piton 6 normally preed by a coil pring 7 toward one end of the bore, and i vented to the atmophere on the pring ide of the piton, by mean of a paage 08 opening into the hollow handle 9. A cap 09 i threadedly engaged with and cloe the open end of the houing 4 and a hub formed thereon ha an extenion which overlie and cloe the end of the cylinder bore f. The hub f l i axially bored and provided, within the chamber 103, with an interecting paage 2 which divide the hub bore into a pair of indi vidual portion one of which provide a bleeder opening 3 at the end of the cylinder bore of and the other of which i threaded to receive the threaded tem 4 of a needle valve 6 whoe conical point may be made, by rotating the threaded tem f4, to advance toward or recede from the pening 13. A locknut T i provided on the valve tem if 4 o that the latter may be locked in any poition to which it i adjuted. The chamber of i entirely filled with fluid, pref erably a light oil, through a uitable filler opening cloed by a crew 8, and a cover 9 i thread 4 edly engaged with the cap f 09 o a to protect the valve tem 4 againt being diturbed or damaged by accidental blow. The crew 8, which act a the filler opening plug, i extended inwardly to erve a a top for the piton o a to prevent the latter from iuing too far out of the bore 02. When the actuating coil 49 i deemergized, prior to welding a tud 13 to the member 2, the arnature 38 will ret at a remote poition with repect to the pole-piece 36 and the end of the rod 37 within the cylinder bore of will be pot tioned approximately one-fourth of an inch to the right of the left-hand ide of the opening 04 a viewed in Figure 4. Thi will allow fluid from the chamber fo3 to enter and fill the cylin der bore to through the aperture 4. A oon a the coil 49 i energized, the rod 37 will move to the left acro the opening 4. Thi will force fluid contained in the cylinder bore back 6 through the opening fo4 into the chamber 103 and, ince the travel of the end of the rod re quired to travere and cloe the opening 4 i ne-fourth of an inch, the eparation of the tud 3 and the member 2 will occur practically in tantaneouly ince no reitance to thi primary movement i offered by the fluid in the cylinder bore. From thi point on, however, con tinued movement of the rod 3 axially of the cylinder bore i reited ince the only avenue

6 of ecape for the fluid i through the retricted bleeder opening 3. The valve 6 may be et to render the area of the bleeder opening a Small or a large a deired o that the rate of pro greion of the rod or piton along the cylinder bore will be correpondingly affected. Thi gov erning of movenient of the rod 3 will, of coure, alo govern the rate of peed at which the waher 42 approache the projecting end 96 of the trip lever and a a reult the time elaping between etablihment of the welding arc and the releae of the tud to return it into the arc crater in the member f2 may be adjutably and preciely var ied. Thi time for all practical purpoe doe not exceed more than a few econd. The mov able piton 06, in the bore 02, provide for re ilient enlargement of the volume of the cham ber 03 to accommodate the fluid that i forced from the cylinder bore during advancement of the rod 37 and alo create, through the me dium of the pring?o, preure on the fluid in the chamber which ait in returning the rod 37, and the part of the apparatu connected for movement therewith to their normal poition When the actuating coil 49 i deenergized. In Figure 1, I have illutrated a modified form of apparatu, the latter being hown with the part in operative relation jut prior to making a weld. While the majority of part are func tionally identical with thoe of the preferred form of Figure 4, and bear the ame reference numeral, there are everal important difference of contruction. In the apparatu of Figure 4, a eparate ource of preferably direct current i neceary in the welding generator to excite the actuating coil 49. There are, however, everal type of welding machine which afford no cur rent other than the heavy welding current. It i to accommodate thee latter machine that I replace the actuating coil 49 with a coil con tructed of helically arranged convolution of heavy copper bar 2, one end of the coil being connected by a bu bar 22 with the welding current input lead 66 and the other end of the coil being connected by a bu bar 23 with an end of a heavy jumper lead 24, the other end of the latter being connected, a uual, with the connector lug 7 l. Thu the actuating coil i in erie with the welding circuit through the tud 3 and the member 2 and carrie the full welding current. A the time required to make a weld i very hort and a a longer interval of time i required to load another tud into the chuck and reet the mechanim, and in which the part may cool off, the heavy current paing through the coil will not caue the adjacent metallic part to become uncomfortably hot. The coil i encloed in a ferrou houing 2 formed integrally with the handle 9. The Second contructional difference i in the trip mechanim. The armature 38 i here ex tended and provided with a peripheral groove 26 having an inclined ide 27 which, a the armature move toward the left, contact and de pree a pin 28 entering the bore of the tube 3 radially through the caing 6, which pin caue flexing of the articulated link to releae the latch 83. The link i provided with the uual connecting rod 87, but the lever 89 i extended beyond the pivot pin 88 and provided with an overhanging lug 29 which ret againt the ide edge of the connecting rod 87 when the link i fully depreed to provide a top. Intead of the torion pring 92, hown in Figure 4, a coil ten ion pring 3 i provided, attached to anchor pin 32 on the lever 89 and connecting rod 8 repectively. The arrangement of the articu lated link i uch that, When in either, et or re leaed poition, the lever 89 and the connecting rod 8 will lie in angular relationhip and the axi of the pring 3 will lie in a poition offet with relation to the axi of the pivot pin 88. Thi arrangement of the pring will caue the link to Snap from one operative poition to the other. The third contructional difference i in the plunger 77. In Figure 1, the outer periphery of the plunger i provided with crew thread 33 which receive a nut 34. Thi nut may be ro tated to advance it axially of the plunger o a to compre the pring 79 and thereby provide for more forcible movement of the tud. 3 into the arc crater 4. While the greater part of the operation of the tud welder of my invention i entirely auto matic, there i one tep, other than loading addi tional tud into the chuck, and depreing the perating puhbutton, that mut be performed manually. The mechanim require "cocking' between each weld; that i, the plunger TT, after being releaed by the latch 83, mut be returned to be held by the latch before the next welding operation may be uccefully performed. Thi 'cocking' may be accomplihed, before or after an additional tud ha been inerted in the chuck, by placing the end of the chuck or tud againt a projecting object and preing the body of the Stud welder toward the object. Thi will caue the ram 29 to be moved axially whereupon it Will contact the plunger and carry the latter along with it until the flange 18 coincide with the latch 83. When thi occur, the latch pawl 84 will Snap upwardly to contact the ide of the flange, the plunger being thereafter held in thi poition until it i releaed by operation of the trip lever. claim: 1. Apparatu for welding a member forming ne electrode of an electric welding circuit to another member forming another electrode thereof, compriing mean for movably upport ing and releaably engaging one of aid elec trode, mean for moving aid one of the elec trode away from the other of aid electrode to etablih an arc gap between aid electrode, and mean perative a predetermined interval of time after etablihment of aid arc gap for re leaing aid one of the electrode from aid mov. able Supporting mean to uddenly bring aid electrode together. 2. Apparatu for welding a member forming one electrode of an electric welding circuit to another member forming another electrode there of, compriing mean for movably upporting one of aid electrode, electromagnetic mean for moving aid one of the electrode in one direction away from the other of aid electrode o a to etablih an arc gap between aid electrode, and mean operative during movement of aid one of the electrode in aid one direction and independ ent of Said electromagnetic moving mean for moving aid movable electrode in an oppoite di rection. 3. Apparatu for Welding a member forming ne electrode of an electric welding circuit to an other member forming another electrode there of, compriing axially extenible mean for mov ably upporting one of aid electrode, electro magnetic mean for moving aid one of the elec trode and it upport in one direction away from

7 3 7 the other of aid electrode to etablih an arc gap between aid electrode, and pring-preed m3an operative a preet interval of time after etablihment of aid arc gap and during con tinued movement of aid electrode upport for returning aid eparated electrode into mutual contact. 4. Apparatu for welding a member forming ne electrode of an electric welding circuit to an other member forming another electrode thereof, compriing a upport removably engaging one of aid electrode, mean on aid upport for hold ing the other of Said electrode, primary mean for moving aid electrode holding mean and the electrode held thereby away from aid firt-men tioned electrode whereby an electric arc i etab lihed between the Separated electrode, normal ly retrained econdary mean, for bringing aid electrode together after eparation thereof, and mean operative during movement of aid pri mary electrode moving mean for releaing aid retrained econdary mean for bringing Said electrode together.. Apparatu for welding a member forming one electrode of an electric welding circuit to an other member forming another electrode thereof, compriing a Support removably engaging one of Said electrode, mean on aid upport for hold ing the other of aid electrode, primary mean for moving aid electrode holding mean and the electrode held thereby away from aid firt-men tioned electrode whereby. an electric arc i e tablihed between the eparated electrode, nor mally retrained econdary mean relatively. axially movable with repect to aid primary electrode-moving mean for bringing aid elec trode together after eparation thereof, mean operative during movement of aid primary elec trode noving mean for releaing aid retrained Secondary mean for bringing aid electrode to gether, and mean for yieldably retraining move ment of Said primary moving mean. 6. Apparatu for Welding a member forming one electrode of an electric Welding circuit to an other member forming another electrode thereof, compriing a upport removably engaging one of aid electrode, mean on aid Support for hold ing the other of aid electrode, primary mean for moving aid electrode holding mean and the electrode held thereby away from aid firt-men tioned electrode whereby an electric arc i e tablihed between the Separated electrode, nor mally retrained econdary mean relatively axially movable with repect to aid primary electrode-noving mean for bringing aid elec trode together after eparation thereof, mean operative during movement of aid primary elec trode moving mean for releaing aid retrained Secondary mean for bringing aid electrode to gether, and adjutable mean for variably yield ably retraining movement of aid primary nov ing mean. 7. Apparatu for Welding a member forming one electrode of an electric welding circuit to an other member forming another electrode there of, compriing a caing, mean for removably Supporting Said caing adjacent and in paced relation to a firt of aid electrode, a ram mounted for movement in aid caing. in a direc tion away from aid firt electrode, mean on aid ran for holding a econd electrode to be moved, * upon movement of aid ram, from a poition con tacting Said firt electrode to a poition Spaced therefrom whereby an electric arc i etablihed between aid electrode, mean in aid caing Z for moving aid ram, retrained preure mean in aid caing and engaging aid ram for mov ing aid econd electrode into engagement with Said firt electrode after the etablihment of aid electric arc therebetween, and mean connected to be actuated by aid ram moving mean for releaing aid retrained preure mean. 8. Apparatu for welding a member forming ne electrode of an electric welding circuit to another member forming another electrode there of, compriing a caing, mean for removably up porting aid caing adjacent and in paced rela tion to a firt of aid electrode, a ran mounted for movement in aid caing in a direction away from Said firt electrode, mean on aid ram for holding a econd electrode to be moved, upon movement of Said ram, from a poition contact ing aid firt electrode to a poition paced there from whereby an electric arc i etablihed be tween aid electrode, element providing a mag netic circuit including an armature connected and movable with aid ram, mean for creating magnetic flux in aid magnetic circuit to move Said armature and ram, a plunger adjacent aid ran and movable in a direction counter to the direction of movement of aid ram, aid plunger being operatively connected to aid ram to impart Counter movement to the latter, preure mean for moving aid plunger, releaable mean for holding Said plunger againt movement, and mean engageable by and during movement of Said armature for releaing aid plunger holding e.s. 9. Apparatu for welding a member forming one electrode of an electric welding circuit to another member forming another electrode there of, compriing a caing, mean for removably Supporting aid caing adjacent and in paced relation to a firt of aid electrode, a ram mounted for movement in aid caing in a direc tion away from Said firt electrode, mean on aid ram for holding a econd electrode to be moved, upon movement of aid ram, from a poition con tacting aid firt electrode to a poition paced therefrom whereby an electric arc i etablihed between aid electrode, element providing a magnetic circuit including an armature connected and movable with aid ram, mean for creating magnetic flux in aid magnetic circuit to move aid armature and ram, a plunger adjacent aid ram and movable in a direction counter to the direction of movement of Said ram, aid plunger being operatively connected to Said ram to im part counter movement to the latter, a com preible pring interpoed between aid caing and aid plunger for moving the latter, a relea able latch on aid caing and engaging aid plunger for maintaining aid pring in compre ion, and mechanim including a trip lever opera tively connected with aid latch, aid trip lever being dipoed in the path of movement of aid arnature whereby the movement of aid arma ture may releae aid latch. ka 10. apparatu for welding a member forming one electrode of an electric Welding circuit to an other member forming another electrode thereof, compriing a caing, mean for removably up porting aid caing adjacent and in paced rela tion to a firt of aid electrode, a ram mounted for movement in aid caing in a direction away from aid firt electrode, mean on aid ram for holding a econd electrode to be moved, upon movement of aid ram, from a poition contact ing aid firt electrode to a poition paced there from - whereby an electric arc i etablihed be

8 6 tween aid electrode, element providing a mag netic circuit including an armature Connected and movable with aid ram, mean for creating magnetic flux in aid magnetic circuit to move aid armature and ram, a plunger adjacent aid ram and movable in a direction counter to the direction of movement of aid ram, Said plunger being operatively connected to Said ram to im part counter movement to the latter, preure mean for moving aid plunger, releaable mean for holding aid plunger againt movement, mean engageable by and during movement of aid armature for releaing aid plunger holding mean, a houing fixed to aid caing, aid hou ing having a bore therein provided with a vent aperture, a rod Secured to Said armature and lidably entering aid houing bore, mean for admitting fluid into aid houing bore to be forced through aid vent aperture upon move ment of aid rod in aid bore by aid armature, and mean for variably obtructing paage of aid fluid through aid. Vent aperture. 11. Apparatu for Welding a member forming ne electrode of an electric welding circuit to another member forming another electrode thereof, compriing a caing, mean for remova bly Supporting Said caing adjacent and in paced relation to a firt of aid electrode, a ram mounted for movement in Said caing in a direc tion away from aid firt electrode, mean on aid ram for holding a econd electrode to be moved, upon movement of Said ram, from a poition contacting aid firt electrode to a poition paced therefrom whereby an electric arc i etablihed between aid electrode, element providing a magnetic circuit including an armature connected and movable with aid ram, mean for creating magnetic flux in aid magnetic circuit to move aid armature and ram, a plunger adjacent aid ram and movable in a direction counter to the direction of movement of aid ram, aid plunger being peratively connected to Said ram to im part counter movement to the latter, preure mean for moving aid plunger, releaable mean for holding aid plunger againt movement, mean engageable by and during movement of aid armature for releaing aid plunger hold ing mean, a houing fixed to aid caing, aid houing having firt and econd bore therein, a chamber for containing fluid and port provid ing communication between aid chamber and Said firt bore, a cover on aid houing having an extended portion cloing aid firt bore and hav ing therein an opening to provide a vent for aid firt bore, a rod, Secured to and movable with aid armature, lidably entering aid firt bore, the end of aid rod having it normal poition of ret beyond aid port and aid vent opening of aid firt bore whereby aid port are uncov ered to admit fluid from aid chamber into aid firt bore, aid rod upon being moved along aid firt bore, by Said armature, forcing fluid con tained in aid latter bore through aid vent open ing into Said chamber, a valve in aid houing cover for variably obtructing aid vent opening, and a pring reited piton in and movable axial ly of Said econd bore a fluid i forced into aid chamber from aid firt bore. EDWARDF.NELSN