US2443251A - Blowpipe machine - Google Patents

Description

A. M. KELLER BLOWPIPE MACHINE June 15, 1948.

6 Shets-Sheet 1 Filed May 30, 1944 INVENTOR ARTHUR M. 'KELLER BY ATTORNEY I I W A. M. KELLER BLOWPIPE MACHINE June 15, 1948.

6 Sheets-Sheet 2 Filed May 50, 1944 INVENTOR ARTHUR M. KELLER ATTORNEY June 15, 1948. I I KELLER 2,443,251

BLOWPIPE MACHINE Filed May 30, 1944 6 Sheets-Sheet 3 INVENTOR ARTHUR M.-KELLER ATTORNEY June 15, M K L ER 2,443,251

BLOWPIPE MACHINE Filed May 30, 1944 e Sheets-Sheet 4 INVENTOR ARTHUR M. KELLER ATTORN Y June 15, A M, K LL R 2,443,251

BLOWPIPE MACHINE Filed May 50, 1944 6 Sheets-Sheet 5 x A Wm MHHHH I INVENT QR ARTHUR M. KELLER ATTORN EY June 48.

ELLE BLOWPIPE MACHINE Filed 30' 1944 6 Sheet s 6 v /771 B 102 Y r v v I 1/ Z: w [40 r I I 42 I 12's /27 k NVENTo ARTHUR M. KELLER Patented June 15, i943 BLOWPIPE MAcHiNn Arthur M. Keller, Livingston, J .,;assigiior to The Linde 'AirProductsc mpa y, a corpora tion of Ohio Application May 30, 1944, said-st; acacia" 22 Clahns.

This invention relates to blowpip'e machines,

and. more particularly to machines for moving one or more cutting blowpipes transversely of a workpiece or elongated ferrous metal stock to cut the stock into shorter lengths. v I I In a steel rolling mill, the rolling operation produces elongated bars, billets, or slabs, which may be round, rectangular, or other shape in cross section Blowpipe machines heretofore havebeen limited to operate upon only one shape of bar or,

slab, or have required elaborate adjustment to convert the machine for operation upon another shape. It is therefore a principal object of the present invention to provide a blowpipe machine which will operate substantially equally well 'on round, rectangular, or other shaped stock, with little or no adjustment for the transition from one shape to the other.

One type of prior blowpipemachine comprises a boom adapted to be extended over the stock from a position clear of the stock, and, mechanism on the boom for advancing the blowpipe across the stock during the cut. Other objects-of the present invention are to provide, in a blowpipe machine of the boom type,'improved means for locating the boom over the workpiece, for traversing the blowpipe across the stock, and forre tracting the boom and the blowpipe. I

The cutting operation performed by a machine of this type is desirable for trimming the ends of metal stock, or for cutting the same into lengths;

and to increase the speed and adaptability of pro-v duction, further objects of the invention are to provide a machine which can make a plurality of simultaneous cuts, such as trimming both ends, or making intermediate length-severing cutsQand which can be adjusted to vary the spacing between such simultaneous cuts. These objects are preferably accomplished by providing a plurality of blowpipe mechanisms supported on the same boom and laterally adjustable with respect to each other, and common means for actuating these mechanisms. i

It is desirable when cutting stock of square or rectangular cross section to start the cut with the blowpipe held at a trailing angle and to complete the cut with the blowpipe held at a leading angle.

It is also desirable to retract or raise the blow-'- I pipe and its associated mechanism clear of the stock at the completion of the cut, regardless of the cross-sectional shape of the stock. Accordingly, further objects of this invention are to provide a blowpipe machine having improved mechanism for these purposes, and to provide-common means 'for actuating a plurality of laterally spacedblowpipes simultaneouslyfor these pur- Other objects and features of novelty will be .,,apparent' as the following description proceeds,

" with reference to the accompanying drawings, in

Which:

, Fig. 1 is a side elevation of a machine according to the vpreferredembodiment ofthe present invention showing the parts in retracted position in '10 "full lines, and in dotted lines in projected position in operative relation to the work;

Fig- 2:,isa top plan viewof the machine shown in Fig;- ;1,; i Fig. ,3 is, an elevation of the lower portion of the side.- of, themachine opposite from that shown in Fig. 1, with the cover removed to show details of control mechanism mounted on the base of the machine;

Fig. 4 is a rear elevation of the machine, cover 2t boxes being removed to show the internal construction; V,

Fig. 5 is a partial front elevation of the machine, showing the blowpipe supporting mech- ;anism;...' l c a V Fig.6 is a rear elevation of. the blowpipe supporting mechanism shown in Fig. 5; I 1

Fig. 7 is an enlarged vertical, cross section taken on the line of Fig-2 throughthe blowpipe vg supporting mechanism and showing thetrailing u s H Figs. 8, 9 and lfljareenlarged sections showing variousdetails of the machine. Fig. 8 is taken along the line 8-,-8 ofFig. 2; Fig. 9 is taken along -the. line 9'9 of Fig. 6; and Fig. 10, is taken along theline |0,-l0ofFig.9;

Fig. 11 is a longitudinal section through the feed beampshowing-the cams for tilting the blowpipe mechanism; V

Fig. 12 is a planof the mechanismfor shiftin the, cams shown in Fig. 11; and i i Fig.' 13 is, a section taken along line l3l3 o Fig.12, a

In the drawings the workpiece or elongated ;n1eta1 stock is represented by a'steel billet A, of round, rectangular or other cross section, which may be supported by and propelled into position by a conveyor. which ,is represented by a series of driven rollersjR, or the stock maybe propelled along such rollers into cutting position. 60

base K, which may be abaseplate forming part of a wheeled truck movable on rails into position adjacent't-h stock A onthe conveyor represented by the rollers R. .On the base K, a pair oflinksL are pivotally mounted, the upper ends of which piv- In general the blowpipe machine comprises a otally support a main boom T in position disposed transversely to the conveyor table.

Longitudinally slidable within and extendin through the front end of the main boom T is a fluid pressure piston P 'for causing a swinging.

movement of the main boom T while maintaining it horizontal at all times. Thus the main boom T, is moved from the retracted position shown in full lines in Fig. 1, to the parallel position show in dotted lines. The main boomT is swung,for; ward and down upon the stock}; untilstopped by.

the same, to bring the blowpipe 'B into position for operating upon the billet A or other stock on the rollers R. The piston P is alsooperable for; the reverse movement, to swing the main boom T upwards and backwards to return it to retracted position after the completion of each cut,

For. advancing" and returning theblowpipe B I across the metal stock to be cut, the carriagejor feed beam D is propelled in a forward direction and retractedby means of arack W drivenbyi gearing Gfrom a, motor M. This motor maybe energized for example by a motor generator set, and by'suitable electriccontrolssuch-as a-rheostat, the motor speed can be varied through a wide range of appropriate oxy-acetylene cut-tingspeeds.

The feed beam D at its frontend carries a sup-- port S which is parallel to the longitudinalaxis of the stock to be cut, and on which one or more blowpipe units U are transversely adjustably mounted. In the form shown, thecentral unit is permanently installed at the center of the -machine, and the other two are adjustablefor length Each unit comprises a of stock between cuts. frame F on which is pivoted a-blowpipe supporting and nozzle-projecting trailing arm J, the end of which extendsrearward from such pivotalcon nection. The rear end portion of the arm J is forked to receive a blowpipe B.

The contour of the underside of the trailing arm J is such that it.mayibe trailed or dragged so as to slide acrossthetop surfaces of various 1 shapes of workpieces as the-'cutprogress'es, and will maintain proper blowpipe relationship with the surfaces of these shapes. The trailing arm'J. at all times prevents mechanical contact between i the stock and the nozzle of the blowpipe and being free to oscillate through a limited movement, in so doing proportionately raises and lowersthe blowpipe B to maintain the-correctrelation be-i im e; T prevent lateral displacement pf tween the gas discharge orifices of the nozzle of the blowpipe and the surface of thestock A. This trailing arm J is so constructedthat in the cut-= ting of round or square bars or slabs within the capacity of the machinethe change'-over-- from one shape to the other is very" simple, and does not necessitate any adjustmentofthe-mechanism of the machine, in most casesentailing only cutting speed and oxygen pressureadl'ustments. I

At the completion of the'cut, the blowpipes -B are simultaneously raised, all gases arevalved off, the large pressure fluid cy-lin'der P raises and pushes back the main boom T, and the feed beam. drive motor M reverses at its maximum speed; automatically stopping when the feed beam reaches its fully retracted position, the machine then being ready for thenextcutting cycleI j 4 through which extend link-supporting shafts I 2, on the outer ends of which are journaled bearings [3 carried by the lower ends of the links L. The upper ends of the links L carry bearings I4 5 journaled on the ends of shaft I5 in the main boom T.

The links L serve to support the main boom T for parallel motionwith respect to the bedplate K, because the shafts i5 on the main boom are spaced apart the same distance as the spacing of the shafts [2 on the bedplate, and the links L are of equal efiective length, although differentlyshaped if desired for clearance purposes,

andsuitably reenforced or transversely framed to p v t side, swa

The fluid pressure cylinder P has a head bracket [6 pivotally mounted on the bedplate link-supporting shaft-l2 between the bearings for the front link. A piston rod I! for the cylinder P isgo pivotally connected by a Wrist pin IB to brackets I9 mounted on the rear link L, Fluid under pressure; preferably compressed air is supplied to the cylinder l? by piping shown in Fig; 3; controlled by a valve 2ilop erated by asolenoid Z I. The com-- 5 5 pressed air system is also; controlled; by a valve-22 which is actuated byan arm 23 movable'with the rear link about its shaft [2.

As shown in Figsl and 3, the rear bracket H ha an upwardly extending post 25 provided with ,a socket 26 to receive a portion of the rear link L, the link and socket having registering apertures to receive a 'locki g pin 21, to retain the-boom in retracted position when not in use, and avoid gravityprojection thereof when the fluid pressure supplyi-sfout off from the cylinder P- in taking the machineout of operation.

The main boom T comprises ahollow elongated box-like structure shown in 'Fign l, formed of a floor plate 30, side plates 3i and 3Z,'and'a topm plate 33." ;Thejside plates have bosses 35 for sup,-

porting the boom supporting shaft it; As shown in Ffig l, thefront end of the: mainboom -T has r bolted thereto a stop bracket 36 for engaging, the top of the workpiece or stock A when themain boom'T is in operative position.

As best shown in Fig. 4, thecarriageor feed; beam D -comprises a trough-like structure, having a bottom wall 40 and side walls ll and 42. The" feed beam D is guided for-movement lengthwise of the-main boom T, by verticalt-hrust guide rollers e5 journaled on thesideplates above andbelow the bottom, wall 40 and extending inwardly to receivetherebetween lateral extensions of the; bottom wallto retain thegsame in a horizontal "feed beam D, side thrust guide rollers Mj'are journaled on the top plate 33 and depend there-.; from to engage the outer surfaces of the side. walls 4| and 42. m e The rack W for'driving the feed beam D back and forth within the m-ain boom T, issecured to undersid gc h 'fe d. b m flo i and meshes with a pinion 4'! on a shaft 48 journaled1 in a pillow block bearing 4 9 mounted on, the main 5 th m floqrpl t fifl an p ss n hrou h a f an e. type hearing: 50 in the main boom, sideplate 3L. T esl v 7. .8 h k d eretoa d vi e...flan e. :5 9q nel=t d by e s eri in 5 .110 asnmcktfi. sel 'mpunt d. on thenu erlen nf. th shaft 48; The-sprocket 4 is driven byfia .chain 55, from a,

respr et'fifi, an idler Sp 'Q.k$ll1' n ipl a.. eis il ke nh chaint t. .UThe sprocketsifi is dr ren' b th m tor.Mthrou hreducmngear:i... ing W mechanism driven byithe drive motor M, limit switches 58 and 59 as shown in Fig. Ziare mounted on the main boom T and are actuated by suitable cams (not shown) which are carried by the feed beam D. The limit'switch 58 is actuated only by overtravel of the feed beam in' the forward direction, but the limit switch 59 is actuated bythe feed beam D reaching its fully retracted position at the end of its movement in the opposite or rearward direction. The limit switch 59 may be provided with spare contacts for the connection of electrical interlocks to prevent the running of the conveyor table R when the machine is not in its retracted position. As a further safety measure a mechanical stop is provided as shown in Fi 1, which comprises a bracket 60 mounted on the main boom plate 39 and engaging angle brackets GI and 52 attached to the underside of the feed beam floor as shown in Fig. 4.

The mechanism for supporting the blowpipes is mounted at the front end of the feed beam D, as shown in Fig. '7; The feed beam D terminates at its forward end in a vertical plate 65 which is rigidly secured to the side walls 42 and the bottom wall 49 and preferably integral therewith. The frame F of the central blowpipe unit U is channel shaped in side elevation, the legs of the channel being bolted to the plate 65 and providedwith upper and lower guideways 66 which adjustably receive the laterally extending support S shown in the form of an I-beam 61.

Each blowpipe unit frame F has a plurality of vertical external stiffening flanges 68 which are provided with spaced depending bearings 69 (Fig. 5) in which is journaled a shaft 10. The front end ofzeach trailing arm J is provided with .bosses 12 mounted on the outer ends of the shaft Ill. The rear end of each trailing arm J is forked to provide a pair of laterally spaced lugs 13 which are pivotally connected to the yoke or fork of the blowpipe holder 14, shown in Fig. 6. The pivotal connection is shown in Figs. 9 and 10, in which the lug I3 carries a screw 15 having a pointed end, engaging a groove 16 in a pin 17 mounted in a boss on the blowpipe holder yoke 74.

The lower surfaces of the trailing arm J and its lugs I3 are hard surfaced with a. wear-resisting material such as a tungsten-cobalt-chromium alloy, or other material which is highly resistant to heat, wear and abrasion. These surfaces comprise three portions which engage the stock at different times during the operation. A curved approach cam surface 18 is adapted to engage the stock ahead of the blowpipe during the starting or initial part of the cutting stroke. This is followed by a downward projection or skid 19, substantially aligned with the nozzle of the blowpipe B and adapted to engage and ride upon the surface of the stock during the main part of the cutting stroke. Finally, an upwardly and rearwardly curved receding portion 80 is adapted to engage the stock during the final stage of the forward stroke or cutting operation.

The-yoke I4 is formed at the lower end of a tubular holder 8! which provides amounting for the blowpipe B. The blowpipe may be of any desired construction, the one shown being a conventional tubular jacketed water-cooled type oxyacetylene cutting blowpipe. The tubular holder preferably provides a floating mounting, in which the height of the blowpipe B is determined by a sleeve 82 adjustably clamped on the blowpipe and engaging the top of theholdenz.

6 The sleeve 82 is preferably set inpositionby the operator. using a gauge while the blowpipe is on the bench before being inserted in the tubular holder BI. I

The yoke 14 also preferablyserves to support structure for providing auxiliary preheating flames if desired, for example to permit flying starts on hot steel, the preheat structure as well as the cutting blowpipe being gauged and protected by the lugs 13. A collar 84 is adjustably mounted on the blowpipe B by means of a cap screw 85 projecting through a slotted hole 86 in the yoke 14. The collar 84 supports laterally extending curved gas conduits 8'! terminating in preheating blowpipe tips 88 arranged to direct preheating gas jets downwardly and inwardly against the work ahead of the jets discharged by the cutting nozzle N of the blowpipe B, as shown in Fig. 6. The conduits 81 are connected by a pipe 90 to a preheat gas mixer 9I mounted on the blowpipe holder 8 I.

For raising the trailing arm J and the blowpipe mechanism carried thereby to elevated or retracted position, the trailing arm J is formed with an integral crank 92 extending upwardly from the central boss 12 at the front end of the trailing arm J, so as to be pivoted therewith about the shaft 19. As shown in Fig. 5, the upper end of the crank 92 moves in a slot 93 between the pair'of stiifening flanges 68, and carries a roller 94 which is engaged by a cam surface 95 carried by a rocker 96 on a shaft 91 journaled in bearings 98 mounted on the lower flange or the I-beam 61. An adjustable stop 99 on the frame F engages the cam surface 95 upon forward movement of the rocker 96 and thereby limits the upward movement of the trailin arm J.

To operate this blowpipe elevating mechanism,

the rear side of the rocker 95 is provided with a roller I00, in turn engaged by a pusher rod I 92 slidably mounted in a bushing I03 provided in the plate 55. The head of the pusher rod passes through a suitable aperture in the I-beam 61, and the pusher rod extends rearwardly therefrom through the bushing I93 and a slide bearing I04 to the rear of the feed beam as shown in Fig. 12, where it passes through another slide bearing I05 and is connected to the piston of a fluid pressure cylinder I06 mounted on the feed beam floor 49.

For tilting the blowpipe during the cutting stroke to start the out at a trailing angle and for completing the cut at a leading angle, the upper end of the blowpipe holder 8I has secured thereto a forked blowpipe tilting bracket I01. The limbs of this bracket are spaced apart and both are notched to receive a blowpipe tilting rod I08 secured in the notches by covers I09 which, as shown in Fig. 2, are spaced apart to give lateral support to the rod I08. Between the limbs of the bracket I01, the rod I 08 is engaged by a hook I I!) which is notched similarly to the limbs of the bracket I01, the notches serving as aut matic take-up for Wear. The hook H0 is in turn connected to the forward end of a pull rod I I2 which extends rearwardly along the feed beam in freely movable relation.

As shown in Fig. 12, the pull rod I I 2 terminates in a clevis I I3 connected to a crank H4 pinned on a shaft I I5 journaled in bearings I I6 mounted on the feed beam floor 40. A parallel crank II'I pinned on the shaft H5 is connected to a power spring II8. Splined 0n the shaft H5 is a sliding collar I 20 having an upstanding arm IZI car- 'ryingaroller I22adapted to selectively engage sideizofitheitopvfplatei 33.: otrthelmain booms The-11 carmiwhichewillsbe. engaged-why :thecrolleni I 2 2 i is determined by the position of the splinedc'co'llar I 29pwhich is shiftedib'y aalever :I 21 l engagingza' groove "I 28 in thecollar, andimountedrton a-=pivot f The :collar H 20;

is heldiinxselected position. byvaspring pressed; ball I30 engaging. selected notches or drill ipointsx I 3 I in the shaft.

The; central blowpipe unit U'.WhiCh'i'h9.S *beel1 describedwas shown-:in: Fig: 7; is aligned-withthe main-boom T andv is rigidly "secured? to the-1..

I-beam 51 is extended an appropriatedistance 'on n one or both sides zof the central unitito ssupport.

such additional units: In thesezaddition'al:units:J the frame *is closed": by "a backing *platet'l SI instead of the plate 65 for the central-unit.-

To adjust the-additional"blowpipe :units with. respect-to; the center unit for'the purpose of. determining; the length of stocktbetween-cuts a rack I;322 -is securediunde'r the :upperflange of: theI-loeam 67, and mesheswith-vat pinion I33 on a. shaft :I 34 journaled in a'boss on the "plate I3I and operated by ahandle I353 Whenlthis of the Iebeam 6T. Tofacilitate.the settingio'f the additional units, as shown in -Fi"g.::6,' a scale I-38- may-:be provided on the .Lbeam 6'! cooperating with a pointer I39 ontthe: um't,='- for eX--.

ampieon the plate I3I.

The additional blowpipe units are'adapted'for 2 the retraction or'raisingofthe blowpipes thereof:

simultaneously with the central .unitflby. extend-1 ing the cam surface 95 on the rockeryarm 95'.

laterally so that it engagesath'e trailing arm: crank roller '92 Y of these additional units. These ad;

ditional 'units .areadapted for tilting 1.0f their.

blowpipessimultaneously with the'central unit,

by extending the rod I 08 laterally vto'engage slotted members MI! :secured. to the respectiveblowpipe holders BI of the additional units; The

elongatedrslots'of the membersdllll perrnit the trailing arms J 0f the additional units over cocked billetsi- By valving off the center unit and using I only the two outboard units, the maximum length be-.

tween cutsmay be obtained for one machine, or

two or more machines'will allow. .four. or more simultaneous cuts to be made. Obviously. an infinitenumber. of'variations are possiblelusingi,

'to' ride combinations of aplurality'otnnits andla plu;

rality of machines.

In setting up the vmachine. for operation, it;. will be assumed that the baseK has beenproperly-i positioned with respect toi-the-conveyor table-R andthat .the stock A to becut 'hasbeen properly.

" the=action.of' thepower spring I I8, and puns positioned thereonw The pin' 21 is removed-from the socket-26 to release the link- L, and the gas on .theiparticularshape of stock :A won-the co veyortableR; It is alsorassumedtthat th'e ltra pressures are adjusted for the.cuttingpperation Q i 'cut;:.the i hook I I I] "is positioned: in; engagement .the cylinder the upper farther c'ornen f this't'obk, w up ae to drive fthefeed beam at 'the cutting sped it suit the materiallto bevouti When .round "stock is to be cutrthe lpro lons forwtiltingr-the blowpipe may not be 'neces'sary and' i'i de'sired the :hook1I Ill-may be disconnecte fromxth'e rodi. I.08; and' rest=idlyion th'e 'feed beam floor .1 40,? ialthoug-h the machine? will; functio perfectly with. the tilting 'provision' in use. -;.--Bi'1 when stock of. :polygonal tcross \sectionm-is; to the withif the 'rodyl 08, and the lever ;l=211'is-roperate to shift the :rolleriarm-ecollar'r'l 201 130 selectfi'ath cam: I23, ZI 24,1125 or" I 26 :suitable 'ifor-fthe' par ticular size of stocks.

In operation,the largeefluid mpressure cylinder P is actuated; causing" the :pis'tonr-rod "I-I 'toF-s-re tract and": the .levers- Ltcausei the :main boom and all parts rtherleonwto 7 swing ii forward zzan downward until stopped :by the stop-i'ibracketi of the main boom '1' engaging the top of it stock Preferably the cylinders'P isactuate'd by the operator depressing :apushebuttonz which :ii energizes the :solenoid :2.I to operate theizwalve e 20 and consequently admits compresse'damrrztoar.

After the' stop: --bracketw36 'is" brought to rest rz on the topjof therstock; thecylinde'n lllfi isaactu ated'to releasethe pusher -rod :I 02,?whichi'permits. the rock shaft 96 to swingrearwardly;czcarryingi the" cam surface =-with-it. =This..-:permitsrthe: roller .-.9 I- to the trailing arm cranka 92 tor-move rearwardly and 1 permit the trailing iarm -zl -.to :de-.' .4 scend. and contactthe surface of the 'stoc-lti' The drive-motor M" is then started,- preferably. by the operator depressing another push button which simultaneously startsy-the drive motor i the forward. direction andv :bymeans of::silitable electricallyoperated valves turns on :all preheat and cutting; gases. The motor: M-wthro-ughrree .duction gearing-V drives theisprocket' 56Rwhich by means of thechain- 55- drives the sprocket-5.4; r Through the shear'pin '53 thesprocket 54: drivesthe flange 52 and itsshaftlswand thepinion'wfl thereon, which meshing with the mack-KW drives 45 $1161 feed :beamv D forward, guided f by; the rollerssyi 45 and 46 withinthe main boom T.

Upon forward movement of the carriage one: feed beam .Dwhen. polygonal stock -is being out: duringthe initial portion of the .-cutting rstroke:;:i=i the forward. poition. l8-which .is curved downwardly and rearwardly: first engages the 'upper and nearer corner of .the-stock andas the-trail;- ing arm 4 J moves forward, the .:-surfaoe 'IBwri-des along this corner until. the skidportionfIS passes overthe corner onto the mama-portion .oizxthe surface of the stock. At thebegin'ninge otizthis stroke; the power spring: IIB hOldSxtheilOd I02 forward so that .the transverse :rod .1 I] 8 holds-the blowpipes B rearwardlyj;inclinedw Thusfztheszcut is started with the blowpipe positionednin t'he-is;

trailing angle shown in-Fig-. :7.

Duringa'the main portion of the-:cuttin'gsstmke, the skid .I 9" rides "over 1 therzmaj or portioniofsthe surface; of the stock- Meantime-.theerollep I22 having engagedone "ofwthe; camsi 1239424; .125 ill or I26; pushesthearm- I2I irearwardly against the "rod l I2 rearwardly, which through h'ook I l0 rod-I68 and-bracket' l lil gradually* tilts the blow- .pipe; B about I the pivot '11, 'during' this "inter mediate part of the forward-movement *of the feed beam D." After v.the intermediate-or mason portibn of the cuttingf:str'okeputhe skid" I9 "rides" downoe.

during the final portion of the cutting stroke, the skid 19 descends and the upwardly curved rear portion 80 rides down this far corner of the stock. By this time the cam I23, I24, I25 or I26 has completed its action so that the blowpipe has now reached the leading angle, and this leading angle is maintained until the cutting oxygen jet has passed through the final triangular portion of the stock and has completed the cut.

After the cut is completed, the operator presses a push button which stops the motor M. However, if the operator should fail or unduly delay to press the button, and over-travel of the feed beam takes place, the limit switch 58 is tripped by the cam carried by the feed beam, and stops the motor M when the feed beam reaches its fully extended position. At the same time upon completion of the cutting stroke, fluid under pressure, preferably compressed air, is admitted to the cylinder Hi6, which pushes on the rod I02 in engagement with the roller I and rocks the shaft 9?, causing the cam surface 95 engaging the roller 94 to tilt the crank 92, thus raising the trailing arm J and the blowpipe and preheat tips carried thereby, clear of the stock for the return movement. Preferably a single push button is provided, which in addition to actuating the cylinder I96, alsocauses the shutting off of all gases, stops and reverses the drive motor M at a predetermined speed higher than the cutting speed, and reverses the direction of flow of air to the large operating cylinder P. When the feed beam reaches its fully retracted position,

' the limit switch 59 stops the motor M.

This invention is not to be limited to the precise details disclosed, but instead the invention is to be construed to embrace such embodiments of the broad ideas as fall within the scope of the appended claims.

What is claimed is:

1. Blowpipe apparatus comprising, in combination, a carriage adapted to be propelled in a forward direction during an operation'on aworkpiece; a blowpipe-supporting arm pivotally con-s.

nected to said carriage and extending in a rearward direction from such pivotal connection, said arm having an end portion freely movable vertically and adapted to bear against successive surface portions of the workpiece as said carriage, is propelled in such forward direction; and a blowpipe between said carriage and said pivotal connection and secured to said arm adjacent such freely-movable end portion, whereby said arm maintains the gas jet discharge orifice means of the blowpipe at a substantially constant distance from the surface of the workpiece during such operation.

2. Blowpipe apparatus comprising, in combination, a carriage adapted to be propelled in a forward direction during an operation on a workpiece; a blowpipe-supporting arm pivotally connected to said carriage and extending in a rearward direction from such pivotal connection, said arm having an end portion freely movable Vere tically and adapted to bear against successive surface portions of the workpiece as said carriage is propelled in such forward direction; and a blowpipe secured to said arm adjacent such freely movable end portion, whereby said arm maintains the gas jet discharge orifice means of the blowpipe at a substantially constant distance from the surface of the workpiece during such operation, in combination with mechanism operable to progressively vary the inclination of said blowpipe from a trailing angle to a leading angle relatively to said surface during free vertical and forward movements of said end portion of the blowpipe-supporting arm. I

3. Blowpipe apparatus for thermochemically cutting elongated stock such as solid steel bars of round and rectangular cross section, such apparatus comprising a carriage having an extension adapted to overhang said stock during a cutting operation thereon; propelling means adapted to advance said carriage in a forward direction toward said-stock to move said extension transversely of and above said stock; a blowpipe-supporting arm pivotally connected to said extension and extending rearwardly and downwardly from such pivotal connection, said arm having an end portion freely movable vertically and adapted to bear against successive surface portions of the stock as said carriage is propelled in such forward direction toward said stock; and a cutting blowpipe disposed between said carriage and said pivotal connectionand secured to said arm adjacent such freely-movable end portion, the construction and arrangement being such that said arm maintains the gas jet discharge orifice means of said blowpipe at a substantially constant distance from the surface of the stock during the cutting operation.

4. Blowpipe apparatus for thermochemically cutting elongated metal stock such as solid steel bars of round and rectangular cross-section, such apparatus comprising a carriage having an extension adapted to overhang said stock during a cutting operation thereon; propelling means adapted to advance said carriage in a forward direction toward said stock to move said extension transversely of and above said stock; a blowpipe-supporting arm pivotally connected to said extension and extending in a rearward direction from such pivotal connection, said arm having an end portion freely movable vertically and adapted to bear against successive surfaceportions of the stock as said carriage is propelled the gas jet discharge orifice means of said blowpipe at a substantially constant distance from the 7 surface of the stock during the cutting operation,

and mechanism for progressively varying the angular position of said blowpipe during free vertical and forward movements of said end portion of the blowpipe-supporting arm, to discharge the oxygen cutting jet rearwardly at the beginning and forwardly at the completion of the cutting operation.

5. Blowpipe apparatus as claimed in claim 3, wherein said carriage is reciprocable, said propelling means also is adapted to retract said carriage in a direction away from the stock and to its initial position upon completion of the cutting operation, and said apparatus includes mechanism for lifting the freely-movable end portion of said arm and the blowpipe secured thereto relative to said carriage extension and about the pivotal connection of said arm. thereto, to maintain said end portion and blowpipe both clear of said stock during such retraction of said carriage. 1

6. Blowpipe apparatus comprising, in combination, a carriage adapted to be propelled as a forward stroke for an operation upon a workpiece; a blowpipe supporting arm pivotally connected to said carriage and extending in a rearward di- 3 rection from suchpivota-l connect ion;-, and a blowl. pipe carried by the rearward, portiOnof said-arm and located between saidicarriagerand,said; -pivotal connection; said :armrhayingse front cam Blowpipe' ,iapparatus- ;comprisin in com- --bination, a:-carr iage adaptedito be -propelled as a forward stroke for; an, operation -on-a1-workpi.ece; a blowpipe supporting:armpivotallyconnected -to said-carriageand extending in 'a rearward direction; fromsuchpivotalrconneotion; and a-blow-pipe carried by said arm-anddocated between said ear- 4 riage and saidpivotal; connection-, said-armuhaving-a front portion of; itstunderisurface curved downwardly to engage and beartzagainstsucces- -,sive portions of" the; surface, ofthe workpiece and ride run-said surface-as said-"carriage; moves for- -ward:during,-, the initial portion of :its stroke and thereby, raise said blow-pipe, saidv under surface having a :downward proj'ectionat,- the :end of said downwardlyv curved vportion adapted to ride gonto r the surface :of-saidstock as i said-stock :leavessaid downwardly curved portion-andmontinue ineen- ,7 gag-ementwith successive portions of said: surface during: the major. portion, ofsaid forward stroke tomaintain thev nozzle of. saidzblowpipe at asubstantially constantdistance fromnthe: surface. of

the workpiece.

.8. Blowpipe apparatus comprising, ,in combination, a carriage-adapted to berpropelled as a forward stroke: for: an operation; upon, a vworkpiece; ablowpipe. supporting armzpivotally connected .to

- said vcarriage sand extending I rearwardly .,there- 1: from; and ablowpipercarried by the rearward portion of, said arm and-located between said carriageand such pivotal-connection;saidarm having.- a skidportion adapted to; bear against successive surf ace portions :of said workpiece ,as said" .vcarriageeis propelled rinsuch forwardfldirection to maintain the blowpipe nozzle .at a: substantially A constantdistance .fromc the workpiece surf ace;

saidvarm having a; rear: cam portion .of its. ,under surface. curved; upwardly. and rearwardlywtoien-.-- gage successive portions of the. workpiecesurface and ride down the same during the finatiportion of said A forward :stroke to slower .l the blowpipe .nozzle closer .to l the workpiece.

. Blowpipe apparatus comprising, in. comhi :nation a-carriage. adapted .to be ,propelledin a forward directionduring an operation on anworkpiece, a zblowpipe supporting .arml pivotal ly. connected ito the front end of ,said carriage; and extending .rearwardly .therefromsand ,ha-ving Y a a transverse fork; a blowpipe holder. having a transverse yoke; pivoted to said forknandt a blow- .pipe mounted. .in r said ..holder and extending through saidiyokecwithiiits nozzle adjacent the pivotal axis of said yoke and fork.

i l0. B lowpipe apparatus; comprising, .inecombination, a carriagevadapted ltonbelpropelledlin 2. forward direction during an operationona-workpiece ;-,a. b-low-pipe -supporting.-,arm pivotally connected to the frontz-end-of said carriage and ex-.

tending rearwardly therefrom and having-ta transverse fork provided withlugs adaptedztoenage successive portions of the surface of said -workp iece as said. carriage movesforward, to maintain said blowpipe nozzle a substantially constant distance from the surface of said work- -.piece; a blowpipe holder having a transverse yoke pivoted to said fork; and a blowpipemounted in said holder and-extending through said yokeiwith its, nozzlevadjacent the pivotal axis ofsaidyoke and-fork.

' 11..Inib1oWpipe apparatus, a blowpipe-support- 1 -ing varm having a transverse fork,-a blowpipe holder having a transverse yoke pivoted to said tending through said yoke with its nozzle adjacent the pivotal axis of said yoke and fork and a fork a blowpipe mounted insald holder and ex- I collar :inthe fork of said arm and connectedto :said blowpipe and yokeand provided with preheat gas passages terminating intips directed toward thesurface of said workpiece in advance of thegas jet discharge from-said blowpipe nozzle. 12.. Blowpipe apparatus comprising in combi- -nationa feed beam adapted to be propelled in a forward direction-during an operation on: elonngatedametal stock and in 'a rearward direction for a return stroke; a transversely extending support rigidly mounted on the front end of said feed beam; .a blowpipe unit mounted onsaid support and adjustable thereon longitudinally ofisaid support and transversely ofsaid beam, said. .unit

comprising a frame, a blowpipe-supporting arm pivoted to the lower portion ofsaidframe-and extending rearwardly therefrom, .andawblowpipe holder pivotallylcarried by the rear-portion of said arm. g

13.\Blowpipe apparatus .asvclaimedin claim 12, .in combination with a transverse operating-trod connected to said blowpipe holdeiyand means for moving said operating rod. longitudinally of said feed beam to tiltsaid blowpipe holderaabout its pivotal connection to. said arm.

- lenBlowpipe apparatusasclaimedin claim 12, invcombination with a rock shaft journaled-on .said support and having a transversely; extending cam surface, a crank on said blowpipesupporting arm and havingla follower engagingsaidcam surface, and means movablelongitudinallyof said feed beam for rocking said cam surface and causing said crank toraisesaid blowpipe supporting arm and. maintain it clear of. said stock during said return stroke.

15. In a blowpipe machine for thermochemically operating upon elongated metal stock, said machine havinga main boom, and means for supporting said. main boom in position extending transversely of said stock, the improvement which comprises a feed beam extending longitudinally of said main boom and slidably carried therebyand .means fornpropellingsaid feed beam-relative-- to said main boom andlongitudinally-thereof for movement toward and over said stock, a-blowpipe supports-extending transversely of the frontend .ofl saidv beam, and-a; blowpipe supporting arm .pivoted onsaid support and extending rearwardly therefrom, and ablowpipe carried by theurear portion. of said arm whereby) said longitudinal movement of said feedbeam relative to said main .beam,moves said blowpipe transversely of i said stock.

16. Ina blowpipe machine for thermochemically-operating upon elongated metal stock,:.-a base adapted to be mounted atone side of said stock, a-=,mainboom,- and means carried by. said main boom-r-extending-over said stock for: supporting a blowpipe and movable relative to said boom for propelling said blowpipe transversely of said stock, the improvement which comprises front and rear links having their lower ends pivoted on said base, said main boom adapted to extend transversely to said stock and having front and rear portions pivoted respectively on the upper ends of said links, whereby said main boom is mounted for substantially parallel movement with respect to said base and transversely of said stock, whereby said means may be moved with said boom on said links from an inoperative position away from said stock to an operative position toward said stock.

Blowpipe apparatus for thermochemically cutting elongated metal stools-such apparatus comprising, in combination, a support movable toward and away from said stock; a carriage mounted on said support and movable relatively thereto toward and away from said stock; a blowpipe-supporting arm pivotally connected to said carri'age and extending from such pivotal connection in a direction opposite to the direction of movement of said carriage toward said stock, said arm having an end portion freely movable vertically and adapted to bear against successive surface portions of the stock during a cutting operation; a cutting blowpipe secured to said arm adjacent such freely movable end portion; mechanism for moving both said support and said carriage toward and away from said stock and operable to move such freely movable end portion of said arm to bear against said stock and position said blowpipe to start the cutting operation; and means for propelling said carriage relatively to said support and toward said stock to move said arm and said blowpipe across the stock to cut the latter.

18. Blowpipe apparatus for thermochemically cutting elongated metal stock, such apparatus comprising, in combination, a support or boom swingable toward and away from said stock; a carriage mounted on said support and movable relatively thereto toward and away from said stock; a blowpipe-supporting arm pivotally connected to said carriage and extending from such pivotal connection in a direction opposite to the direction of movement of said carriage toward said stock, said arm having an end portion freely movable vertically and adapted to bear against successive surface portions of the stock during a cutting operation; a cutting blowpipe secured to said arm adjacent such freely movable end portion; mechanism for rapidly swinging both said support and said carriage toward and away from said stock to and from a position to start the cut and operable to move such freely movable end portion of said arm to bear against said stock and position said blowpipe to start the cutting operation; and means operable after said rapidly swinging movement for propelling said carriage relatively to said support and toward said stock to move said arm and said blowpipe across the stock to advance the blowpipe for cutting the stock.

19. Blowpipe apparatus for thermoch'emically cutting elongated metal stock. such apparatus comprising, in combination, a support movable toward and away from said stock; a carriage mounted on said support and movable relatively thereto toward and away from said stock; a blowpipe-supporting arm pivotally connected to said carriage and extending from such pivotal connection in a direction opposite to the direction of movement of said carriage toward said stock,

said arm having. an end portion freely movable vertically and adapted to bear against successive surface portions of the stock during a cutting operation; a cutting blowpipe secured to said arm adjacent such freely movable end portion; and mechanism for moving both said support and said carriage toward and away from said stock and including means operable to move such freely movable end portion of said arm into position to bear against said stock and position said blowpipe tostart the cutting operation, and means for propelling said carriage relatively to said support and toward said stock to move said arm and said blowpipe across the stock to cut the latter; said mechanism being operable after the completion of the cutting stroke for lifting said end portion and thereby lifting the blowpipe clear of the stock for the return stroke, retracting said carriage to return said arm and blowpipe to starting position, and then retracting both said support and carriage to move said carriage, arm and blowpipe away from the stock.

20. Blowpipe apparatus for thermochemically cutting elongated metal stock of polygonal cross section, comprising in combination, a carriage adapted to be propelled in a forward direction durin an operation on said stock, a blowpipesupporting arm pivotally connected to said carriage and extending in a rearward direction from such pivotal connection, said arm having an end portion freely movable vertically and provided with a work-engaging undersurface, successive portions of such work-engaging surface being adapted to bear against a corner of said stock 7 as said carriage is propelled in such forward direction, and a blowpipe secured to said arm adjacent such freely movable end portion, whereby said arm maintains the gas jet discharge orifice means of the blowpipe at a substantially constant distance from the surface of said stock durtion thereon, propelling means adapted to ad- Vance said carriage in a forward direction to move said extension transversely of and above said stock, a blowpipe-supporting arm pivotally connected to said extension and extending in a rearward direction from such pivotal connection, said arm having an end portion freely movable vertically and provided with a work-engaging undersurface successive portions of which are adapted to bear against successive surface portions of the stock as said carriage is propelled in such forward direction, and a cutting blowpipe pivoted to said arm adjacent such freely movable end portion whereby said arm maintains the gas jet discharge orifice means of said blowpipe at a substantially constant distance from the surface of the stock during the cutting operation, and means cooperating with said blowpipe above its pivot to control the angle thereof to start the cut with the blowpipe held at a trailing angle and to complete the cut with the blowpipe held at a leading angle.

22. Blowpipe apparatus for thermochemically cutting stock such as solid steel bars of round and rectangular cross-section, such apparatus comprising. a 1 reciprocable" carriage @ha'ving tan extension adapted" to overhang said stock during a :cuttingioperation, propell'ing' means adapted to advance said. carriagezin a'forWard: direction to move said extension transversely of .and above said stock, a blowpipe supporting arm pivotally connected to said extension and extending in'a rearward direction from such pivotal connection,

said, arm having anend'portion freely moving ward direction, and a cutting. blowpipe 1 secured to said arm adjacent such freely movable end portion, the construction and arrangement being such" that said arm maintains the 'gas'yjet discharge orifice means of said'blowpipe at 'a substantially constant distance from the surface of the stock during the cutting operation, said propelling means being-also adapted to retract said carriage to its initial position-upon the completion of the cuttin operation, and said apparatus -REFERENCES CITED The following referencesiareof record irigthe file of this'patent:

UNITED STATES PATENTS Number Name "Date 1,858,078 Douglass et a1 Mayi10, 1932 1,885,107 Brown N'ov'. 1, 1932 2,143,969 Biggert, Jr. 1 Jan. 17,1939 2,259,956 Jones -L-Oct; 2191941 2,283,346 I Bucknam et' a1 May 19,1942

' 2,289,786 Jones *July*14,*1'942 2,289,968 Jones Ju1y"14,'*1'942 2,297,343 Young 'Sept.*29,?1942 2,365,235 Younget a1 '-Dec. 19,' 1944 2,365,276 Miller Dec. 19,1944

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