US2669139A - Apparatus for rolling threads into metal pipe - Google Patents

Description

Feb. 16, 1954 Filed April 28, 1949 H. J. FINCH APPARATUS FOR ROLLING THREADS INTO METAL PIPE 6 Sheets-Sheet l INVENTOR HARRY J. FINCH v Feb. 16, 1954 Nc 2,669,139

APPARATUS FOR ROLLING THREADS INTO METAL PIPE Filed April 28, 1949 6 Sheets-Sheet 2 INVENTOR HARRY J. FlNcH Feb. 16, 1954 H. J. FINCH 2,669,139

APPARATUS FOR ROLLING THREADS INTO METAL PIPE INVENTOR HARRY J. FINCH H. J. FlNCH APPARATUS FOR ROLLING THREADS INTO METAL PIPE Feb. 16, 1954 6 Sheets-Sheet 4 Filed April 28, 1949 MWQN INVENTOR HARRY J.F|NCH 5 47, M

W JMmH Feb., 16, 1954 H. J. FINCH APPARATUS FOR ROLLING THREADS INTO-METAL PIPE Filed April 28, 1949 6 Sheets-Sheet 5 Feb. 16, 1954 H. J. FlNCH APPARATUS FOR ROLLING THREADS INTO METAL'PIPE Filed April 28, 1949 I 6 Sheets-Sheet 6 INVENTOR Patented Feb. 16, 1954 UNITED .lS ENT srPARA'rus-ro ROLLING THREADS INTO ETAL PIPE Harry-J, Finch, OiLGity, Pa., .assignor to Jones.\&- 'Laughlinl Steel Corporation, Pittsburgh, 3a., a

corporation of Bennsylvania "Applicationi'April'28, 1949, Serial No."90,071 L51Cl'aims. (01.1'80-6.)

pipeiand 'new' and: improved metal pipe having threads rrolled. thereinto whereby inrportant:--.advantages: both" in-the rolling, of the: threadsii-nto the;- pipe and in the structure rand. use. of -=.-the threaded piper-are obtained.

Metal pipe of certain characteristics may be threaded .by rolling- Relatively thin-walled pipe -01" tubing and "heavier-walled pipe of 'isufiicient ductility may he thus'threaded. For'purposes of :ex planati-on' and illustration I shall discuss, the threading. of thin-walled steel'tubing although mywinventioniis not limited in all Of' -itS1'aSp6CtS to the: threading. of such'tu-hingbut may be: otherwise embodied? and practiced.

:Lengths of thin-walledsteel. tubing are-fastened togethervend toend'; to make long tubes for variouspurposes, as, for example, so-call'ed -:shot hole vcasing. Desirably each. length. or-section is somewhauexpanded-at' one end so -that it'will telescope with the--nnexpandedioppositeend; of a similar section and threads are rolledinto-the telescoping ends so that theymay be screwed together. The thread rolling operationtisrapid and economical and fcrrelativel-y thin-walled pipe and pipe-*ofr-sufiicient ductility is far less costly than cutting-threads by the conventional method moreover, astronger and. otherwisesuperior; product is produced.

It has heretoiorebeen proposed? to roll threads into thin-walled tubular articles but the threads --l1lhih have been produced'have been in-feriorand no practicable Way ofcthreading relatively long sectio-nsof v pipe has been developed. Ihaverdevised a mac-hine for rolling threads into metal pipe which :accomplishesthe. result in "a 1 highly accurate, efiect-ive and efiicient manner. I-:ha:ye also devised a method of rolling threads into "metal :pipe whereby important advantages are obtained. :2 have also devised a new thread form of: importantly increased strengthuand efiiciency relatively to rolled threads heretofore developed.

12in rolling threads into thin-Walled? steelttuhing iti-has heretofore-been considered necessary to effect a partial shearing of the metal tosharply displace metal-substantially radially to form the --:threads. The result :has'heena lackof uniformity in :the threads, -:the thread dorm differing especially in articles: of: steel of-different characteristics, and being in any-Yevent subjectto early iailurecrepullinga out undersload. .lI-lhave discovered-what thee-conception 171113 1 the z-srclled 2. threads should be formed by: a-w-shearingacticnafis fallacious and: that it is not necessary to-.-so-.-torm them. On the contrary, I formz za vastly; superior and more uniform thread through causing-a flow of themetal whileavoiding-any substantialsheaming action. -I*rotate the pipe genera-1v about its axiscand during such rotation simultaneouslyrenrgage the pipe internallywand externally at; rad-i -ally-opposed portions-thereof and squeeze rthe metal so as'to-vcause it to flow without anvsubstantialshearing to form threadsprojecting from one surface of the pipe while-deforming: the-opposite surface so thatmetal-throug-hout' the; en,- tire. thickness of the pipe is flowed-and reshaped during thread formation. I, preierablyA-form--..-in the pipe by simultaneous.internal and external rolling at radially [opposed .portions I thereof: ternal and external-alternately arranged grooves and projections in generally helical form and during the formingof such grooves-.-and;,-proiec tions somewhat ioreshortenthe-pipe and there.-

.aiiter flow the metal at-the groovesland projections without any substantial/shearingof' the metalrto dorm; av thread-at. one surface of the pipe. :Ldesi-rably form. in-thatway a thread 'whose side Walls ore substantially parallel to-.each.other.

rolling into metal pipe threads: whosesside wallsare substantially parallel to cache-other]:

desirably r rotate thev pipe generally about -its axis and during such rotationpress the: metal from the-.surface of the pipe opposite thesurface to bethreaded toward thesuriaceto the ,threaded,,. limitingthe metalfiow at thescrests ,of the incipient threads. and forcing theemetal laterally generallyparallel to the crests to: form generally. square corners on. the: threads. may dorm in vthe pipea generally helical corrugation.

..I. further provide a method of rollingvthreads into metal pipe wcomprising engaging l-the r-pipe internally-and externally by rotating dies which squeeze the r-metal. of the-pipe.-therebetween-and cause rotation of the pipe (duringuthetthreading operation and hyoneof the dies flowing the metal withoutianysubstantialshearing of. themetaliinto a thread forming :cavityin. the; other.- die.

,I roll into metal pipe threadsof new-and: improved shape which-are vastly stronger than/the previous rolled .-threads: both' vrith respect tovpu-lli-ng out-and withrespect to failure under load. .I provide metal pipe having a! rolled thread atone surface thereof, the oppositesurtace ofthe pipe having a.- helical depression whose .dimension axiallyi of thepipe at; its,-.bottom is not hover -about I radially opposite the center of the thread crest, and. a helical projection radially opposite the thread throat and merging into the depression. The dimension axially of the pipe of the helical projection opposite the thread throat is preferably at least one-third greater than the dimension axially of the pipe of the thread throat.

I further provide metal pipe having at one surface thereof a rolled thread whose sid walls are substantially parallel to each other, the opposite surface of the pipe having a helical depression whose dimension axially of the pipe at its bottom is not over about half the dimension of the thread axially of the pipe, the depression being disposed radially opposite the center of the thread crest, and a helical projection opposite the thread throat whose dimension axially of the pip is at least one-third greater than the dimension axial ly of the pipe of the thread throat and merging into the depression. The side walls of the helical depression are preferably inclined toward each other and the side walls of the helical projection are preferably inclined toward each other and the depression and the projection preferably merge into each other. Desirably the thinnest section at the thread is at least about eighty per cent of the thickness of the pipe wall at a point removed from the thread.

So far as apparatus is concerned one of the fallacies of thread rolling apparatus as heretofore developed has been that the dies are mechanically forced together, virtually eliminating the possibility of adequate metal flow to form a thread as above described. The machine design has been consistent with the fallacious theory that the metal should be sheared during thread formation. Not only have I discovered that the metal should not be sheared during thread formation but I have also devised improved apparatus for rolling threads into metal pipe which insures proper metal flow. I employ hydraulic means for forcing together the dies which roll the threads into the pipe. By use of such means I can attain a relatively smooth flow of the metal which is not possible, or at least not regularly obtainable, with mechanically operated dies.

In use of my apparatus as the dies are pressed together hydraulically the metal is first bent or corrugated during which time the tube is somewhat foresh-ortened. After a time, perhaps twenty or mor revolutions of the dies, the metal begins to flow from the surface of the pipe opposite the surface to be threaded toward the surface to be threaded, but as the extent of flow of such metal is limited at the thread crests by the thread forming die the metal then spreads or flows laterally generally parallel to the crests. Thus I am enabled to form with ease and accuracy threads Whose side walls are substantially parallel to each other, e. g., threads of generally square contour. Moreover, I do so without greatly reducing the wall thickness at the threads, the thinnest section at the threads normally being at least about eighty per cent of the thickness of the pipe wall at a point removed from the thread.

My thread rolling machine has other important features and advantages. One of the most important advantages is that I can With ease and accuracy roll threads into the ends of relatively long sections of pipe which has not been possible with thread rolling machines heretofore available. To accomplish that advantage I desirably employ a guideway for approximately aligning a pipe for presentation of an end thereof to the die means and also employ means engaging the opposite end 4 of the pipe moving the pipe along the guideway to present the first mentioned end of the pipe to the die means, there being means inclined to the horizontal raising the pipe ends upon presentation of the first mentioned end to the die means whereby to free the pipe from the guideway While the threads are being rolled thereinto. Desirably the die means and the pipe engaging means have pipe engaging portions unseating th pipe from the guideway and freely supporting it upon presentation of the first mentioned end to the die means. The pipe engaging portions are preferably rotatable with the pipe during rolling of y the threads thereinto.

More specifically I provide, in a machine for rolling threads into metal pipe, rotary dies adapted respectively to be positioned inside and outside a pipe end when the pipe end is presented thereto and to co-operatively roll threads into the pipe end, one of the dies having a pipe engaging portion adapted to enter the pipe and to position the pipe end for action thereon by the dies, a guideway for approximately aligning a pipe with said portion and means engaging the opposite end of the pipe moving the pipe along the guideway onto said portion, said last mentioned means having a generally conical portion adapted to enter the pipe and to unseat the pipe from the guideway as the pipe is moved into position to be acted upon by the dies.

I further provide, in a machine for rolling threads into metal pipe, rotary dies adapted respectively to be positioned inside and outside a pipe end when the pipe end is presented thereto and to cooperatively roll threads into the pipe end, one of the dies having a portion adapted to enter the pipe to guide the pipe into proper relationship with the dies to be acted on thereby, a guideway for approximately aligning a pipe with said portion and means for feeding pipes one by one to the guideway. I may employ pipe delivery means for delivering pipes laterally into the guideway and means for delivering pipes one by one from the delivery means laterally into the guideway.

I I also provide, in a machine for rolling threads into metal pipe, complementary rotary dies adapted respectively to be positioned inside and outside a pipe end when the pipe end is presented. thereto and to co-operatively roll threads into the pipe end and means for rotating the dies at the same angular velocity in opposite directions to roll threads into the pipe end, said means rotating the inside die in a direction such that when the threads are formed in the pipe the threaded pipe will be fed back off of the inside die upon slowing of the rotation of the pipe relatively to that of the inside die, the diameter of the outside die being greater than that of the inside die so that during rolling of the threads in the pipe end the outside die frictionally engages the pipe end and thereby exerts force on the pipe tending to prevent the pipe from backing off during formation of the threads.

I desirably provide means for maintaining the dies in relatively fixed axial position during formation of the threads in the pipe. Such means may be in the form of portions of the dies which move into interengagement when the dies are relatively moved toward each other. One of the dies may have a radial flange and the other may have a radial groove receiving the radial flange of the first mentioned die.

The dies preferably have co-operating por- "positioned?-forz-abutmenti witheaichoother upon predetermined movemeht of the' dies toward e'aclr dther=whereby t0 limit ithevektent of action-of the'dies-nrithe pipe. The cradialldimensions" of 'the fiang'eiand groove above; referredlto maybe-proportioned so th'at the flangebottoms in "the groove uponpredetermined'smovement of the dies toward' each other whereby to limit the extentof actiomof thedies'on theipipe.

The radial -flange may be on the insidei 'die and may be po'sitioned to 'wbe-z engaged =by-' the pipe ondtoactasa stop "to "limit the'extent to -which the pipeend passes over the insided-ie.

I have"referred above to the fa'ct that L prefer to employ hydraulic means #for relatively moving the dies toward and away from 1 each other"orttransversely of the 1 axes thereof. EOne of the dies; preferably the inside die, :rnay-be mounted for rotation about a fixed axis arid the "othcr' die'may be mounted on a support m'ovable transversely of the axes'of the dies to- -pro videdorpressing-thesecond die against the outside 0f the pipe end so I that the second the "rolls threads 'into -the pipe end co oper-atively with the first' mentioned dle. T Either die may be the .thread formingdie in any particular case, the other die being the "co-operating die which causes the metal to flow 4 as above described-"into the thread: forining cavity' or the thread forming :die. J in threadingapin- *end 'the'thread forming idieiisthe out'side die while in th-reading a box tend the? thread forming die is the inside die.

"The support for' theoutside die is preferably pivotally -mounted on'abasa'thebase' being movable'genera'lly toward and-"away from the inside die and means *b'eing provided "for "ma intaming the support in -desired angular position a-bout'its pivotal mounting'on' -the base. Means are "preferably also provided for adj u'stably :positi'oningthe base in the-d'i rection oi itsmov'ement relatively toi the means for' moving itgenorally toward and away' from the inside die.

r-provide for controlledrelativelyslow movement of "the dies 'toward a each other during a thread forming operation andrela tiv'elv'rapid movement of the-dies awayiromeach other. I desirably employ hydraulic "means for relatively moving the dies toward each other and throttle means operable to limit the "flow of fluid inthe hydraulic means "whereby to determine the speed of-m'ovement'of the dies toward each other. "I may employ a. hydraulically operable piston 'for relatively moving the dies toward each'otherand thethrottle means" may limit the flow of fluid from in front Of the piston. The hydraulic system is "preferably'such that the throttle means functionon'lywhile'the dies 'arebeing moved towardeachoth'er and notwhile they arelbeing moved away from each other. "Thusby adju'stment of the throttlemeans the :movement or the dies"towardeach'other'inay' be controlled as desired withoutaffecting the rapidity of the movement of the dies away from each other.

.I preferably provide roller means. rotatively supporting the inner 'dieagain'st the pressure exerted thereon through the1pipe'b-y"the outer die. LThe inner die may have-a raiditillyoutwardly open I groove adjacent but I axially removedfr'om the thread forming. portionthereof and supporting means comprising'aapluralityjf rollers may engage the die within the ,groove to support it. against the: pressure exerted thereon through-'thegpipe by the second die. ".Means are preferably providd f-for ladiustably. positioning 6 Zthermolier inneans toward 5 and laway ffrom the second die.

aI'he .thread iormingzrdiesi'haver complementary metal i forming races, none 1 for: the faces having thereorraa: helical imetal iorming'proa'ection whose side walls may be? substantially parallet-to-each otherzarid thelother of said faces having"- thereon a helical metal 1 forming projeotion whose side walls-areinclined1tor eachother; which inclined side'fwalls extendrsubstantially:-to -the crest of the second:mentionedfprojection, the projections being in axiallyr'staggered relation. "The inclined side iwalls zspref'erably 'ha've rounded corners at the" :top: andztbottom extremities thereof facilitating'i the idesiredimetaliflow. 'IYhe iace' of the nonethreadtforming :die preferably 'has' thereon a-.zhelicalz;metalrforming projection whose dimension axiallyrof the pipe T at "its crest is not overrabout half lthe dimension of the metal-formingzprojection :ofl-thertnread' forming die axially of: the! pipe.

18y the.improvements-above referred to- I providegreatlyfi-mprovedithreaded pipeathigh speed andl'ow co'st and of greater uniformity-than pipe-with rolled threads heretofore produced. Certain of any:improved features may be-.zused without others but" I pr'efer ii to include all of my. improved: apparatus features in -a' single-machine. lsucliuazmachine is shown inthe accompanying drawings. 1' Other d'etails, objects and advantagesofthe invention w'ill become apparent as the iollowing' desciiiption of them-alanine shown in theidrawings;constituting apresent preferred embodiment ot my apparatus invention, and of my improvec'iimethod and product, or which latter a presentpreferred embodiment is also shown in the drawi ngs, proceeds.

In the drawings Figure 1*is airagmentary elevationalview of the portion'of theapparatusfor feeding pipes tothe thread rollingdies;

Figure'z is avertic'alcross sectional view taken on the line 11-41-01? Figure 1;

Figure 3 is a vertical crosssectional view somewhat similar to Figure 2"but to smaller scale and lookingdn the" opposite "direction so' as to show a" portion; of the thread rolling means, 'theJngure being takenon the line"III--III of Figure 4;

Figure 4 is asomewhat:diagrammatioiragmentary elevational view of the portion of the machine forrolling threads into. pipes, the portion oftheappara'tus shown in'Figuree being positione'dflto the left of the. portion of the apparatus shown in'Figure' 1, part of the apparatus, however; beingshown' in both of Figures 1 and 4;

Figure. 5 is an enlarged-fragmentary detail View partly inJelevationi and. partlyin vertical cross section showing the" thread rolling dies and the mechanism' for operating them;

Figure '6 .is a? fragmentaryelevational viewnof the apparatusrshown .imFigure. 5 .as viewed from the right-hand. end ofifE'iguref 5;

"Figure 7 is a fragmentary elevational view to enlargedscale showing. a portion of. the structure shown in-i Fliguress;

zmy ii-nventionaand IFi'gure; ,1 L .jsaaa; greatly; enlargedzidiagrarmshow ing the shape of the dies and the thread formed thereby.

Referring now more particularly to the drawings and especially to Figures 1 and 4, the apparatus shown comprises pipe feeding apparatus which is shown in Figure 1 and apparatus for rolling threads into pipe ends which is shown in Figure 4. The feeding apparatus comprises a supporting structure 2 comprising an I-beam 3 upon which is carried a member i adapted to be bolted to the I-beam 3 at desired adjusted locations along the I-beam by bolts 5. The member 4 carries at its left hand end viewing Figure 1 one of a pair of co-operating V-shaped guides 6, the two guides 6 being in horizontal alignment and together forming an upwardly open V- shaped guideway for positioning pipes for presentation to the threading dies. The other of the guides 6, shown at the left-hand end of Figure l and at the right-hand end of Figure 4, is carried by the main frame I. of the machine.

There are also provided two generally angleshaped support members 8, one carried by the member 4 and the other by the main frame T, which together constitute an inclined chute or trough for delivering pipes to the guideway 5, b. The members 8 are adapted to be spaced apart a distance determined by the length of the pipes being threaded so that the respective pipe ends are supported by the respective members 8. The member 4 is moved along the I-beam 3 to position the member 8 carried thereby appropriately relatively to the other member 8 which is mounted in fixed position on the main frame so that pipes delivered to the upper end of the chute or trough 8, 8 will be supported thereby at their ends and will roll down by gravity toward the guideway 6, 6.

Also carried by the member 4 is a guide bracket 9 for guiding a rod is carrying at its left-hand extremity, viewing Figure 1, a member H freely rotatable on the rod. The bracket 9 is constructed and arranged so that the member H is approximately aligned with the guideway ii, ii as will presently be described.

Also carried by the I-beam 3 is a bracket it to which is pivoted at IS a fluid pressure cylinder l4 within which operates a piston having a piston rod 15 connected at [B with the end of the rod H3. The bracket [2 may be adjusted along the I-beam 3 as required.

There are provided two similar pipe actuating members ll, one pivoted at 18 to a bracket [9 carried by the I-beam 3 and the other pivoted at 2t to a bracket 2! carried by the frame 1. Each of the actuating members IT is operated by a piston in a, fluid pressure cylinder 22, means being provided as will presently be described for operating the pistons in the two cylinders 22 simultaneously. The respective cylinders 22 are pivotally mounted on their brackets by pivots 23 and their respective piston rods 24 are pivoted to the respective actuating members I! at 25 (Figure 2) Each of the actuating members I! has a generally upwardly extending portion 26 and a generally downwardly extending portion 27. Upon pivotal movement thereof about the axis of its pivot pin in the clockwise direction viewing Figure 2 through action of the piston in the corresponding cylinder 22 the portion 26 swings downwardly and the portion 21 swings upwardly from the position shown in the drawings. Movement of the actuating members I! in the counterclockwise direction viewing Figure 2 is limited by contact of the foot of the portion 21 with the upper surface of its supporting bracket.

The two dies for rolling threads into the ends of the pipes are designated respectively by reference numerals 29 and 39 (Figure 5). The die 29 is adapted to be disposed inside the pipe end when the pipe end is presented to the dies and the die 30 is adapted to be disposed outside the pipe end. The die 29 has a projection 3| adapted to enter the pipe and an inclined annular shoulder 32 between the projection 3! and the die proper. The member H also has an inclined annular shoulder 33. The die 29 is mounted for rotation about a fixed axis and that die and the member I! are coaxially mounted. The die 29 has a radial flange 34 which serves a number of purposes, one of those purposes being to stop and position the pipe when introduced over the die 29.

Before proceeding with a detailed description of the dies and their operating mechanism it may be desirable to describe the operation of the mechanism for feeding the pipes one by one to the dies. The pipes are fed onto the inclined chute 8, 3 by any suitable means, as, for exampie, from a hopper or by hand. In any event, a supply of pipes is continuously provided on the chute 8, 8, the pipes rolling down the chute by gravity and contacting one another as shown in Figure 2. When the actuating members I! .are in the position shown in Figure 2 they restrain the pipes from rolling down the chute with the foremost pipe on the chute in position A. When the cylinders in the pistons 22 are moved up- War-dly by the means for synchronously operating such pistons, which will be described below, the members I? are turned in the clockwise direction about the axes of the pivots l8 and 20 until the portions 26 thereof pass below the level of the chute whereupon the foremost pipe on the chute moves by gravity from position A to position B in Figure'2, the remaining pipes following down the chute by gravity. The foremost pipe is arrested by the stop or stops 28 when it reaches position B. When the pistons in the cylinders 22 are moved downwardly the members i! turn counterclockwise and the portions 26 thereof lift the foremost pipe over the stops 28 so that it rolls down the chute, at the same time preventing the pipes behind from rolling down. The foremost pipe rolls down the chute and drops into the guideway E, 6.

When a pipe is lying in the guideway 6, i3 its axis is slightly lower than the common axis of the die 29 and the member H as shown in Figure 2, wherein the pipe is designated P. With a pipe resting in the guideway 6, 5 the piston in the cylinder I4 is moved toward the left viewing Figure 1 causing the member H to engage the end of the pipe remote from the dies and exert pressure thereagainst toward the left or toward the dies. It should be mentioned that in the embodiment shown the box ends of the pipes are being internally threaded. The member ii pushes the pipe along the guideway so that the box end of the pipe moves over the projection 3| of the die 29. The inclined shoulders 33 and 32 engage the pipe ends and lift the pipe slightly so that as it is presented to the dies both ends are raised from the guideway and the pipe is supported entirely by the dies and the member H. When the pipe is in position to be operated upon by the dies its forward or box end is against the flange 34 and its rearward or pin end is against the shoulder 35 of the member I I. While bers' IT are -turnedin the-clockwise direction;

their portions 21 lifting the threaded-pipe up" out of the-'guideway 6, B-and discharging it tothe'left'yiewing Figure 2.- At the' same timeanother pipe rollsdown the chute against the stop-or stops 28 i as -above' described ready forrepetition "of "thecycles Referring now more particularlyto themechanism for supporting and operating the dies-29 and 30; the die 294s disposed on the end'of a sliaft-' 36*rotatably mounted'in'bearings 31- inthe machine frame (Figure- 5)-.- The shaft 36-is adapted to be rotated bya suitable source of powerthrough a coupling '38; The die-29-may" be formed as an *integral "part'of the shafti36 ormay be removably-attached to the shaft so" that different sized dies maybe selectively used with'the same shaft.

Fixed to the-shaft-"iiii isa-gear39. The gearx' 39 meshes-with a gear 40 fmountedsonanstub' shaft M-r The gear'flfl in turn meshes with a gear 42fixed to' a, shaft 43 which is connected through afieXibIe"coupling 44 "with ashaft 45; M to'whic'h is fixed-a'gear'Mi The gearidtimeshes with a gear 41 fixed to a shaft'48.whichicarries. thedie 3B;- The shafts 45 andi'48 are tjournaled in' asupport 49 *which as :shown' in Figure 5 has 'a yoke-shaped forward end in which" the die.

30 is disposed. The support is mounted atop a'base 58-; A-pivotpin-'5 f is connected withtthe base 50 and projects upwardlytherefrom. The pivot pin =5 I" enters'a bore "iniztheisupport 49 whereby topositionthe support-49 upon'the base ofth'e pin 5 I '(Figure'QIz' Thus'I provide for .pre=v cise angular adjustmentof 'the dief 3fl*"for. co: operation with the die 2 9- whose: position is. fixed.

Thebase-- 50 -has-opposed-' upwardly" projecting t. portions 52 and '53. The support: :49 has *two: crossr' bores 54ineach'"of. which is positioned a pin-551. One end-of eachofithe pins '55 is adapt-. edto bear'against "the portion 52. Each of :the' bores 54 has at its-end'which -is-"adjacent theportion 53' "anenlarged and internally, threaded 5 portion-56. A screw 51 is threadedin'to seachof'i the portions 56 so that'its inner-end engages the adjacent ,end 'of'xthe corresponding pin '55. The portion 53 has openings 58 'ltherethrough 'to provide for access to the screws 51'. The-screws S'F'may have wrench receiving :sockets. in theirv outer. ends; and a .wrenchsuch .assanAllenrwrench may be inserted through each opening. 58 s-tden-t gage and turnithecorresponding screw-r51. The angular; positionvof.the-support 49 .on. the base- 5E1 isqadjnsted by turning the screws 51 tov exert pressure against or. relieve [pressure upon the re-rspectiverpins Eds-the pressurea-ofgthe pins against the 1391171011252 w=-causing gturnineeofsther f' support 49 about the'axi-s,:..of -the Epin 5|: -unti1: it assumes; its; desired :adiusted:.-position:.. Atmthat. timeanutseare tightened: On.lb01l;&l;59iZOOIlIlfiGli(-3di. withcand extendinggunwardly frOm:.*the.base'-:50.;

maintain the support 49 indesired adjusted angular positionupon the base 50.

The frame has a'guideway 6 I receiving a dove-- tailed guiding portion 62'on the bottom of the" base-50-=so that the base tifl and everything carried-byitmay b'e-moved'toward and away from the-die-29.-* A-piston in acylinder 63 has a piston rod 64 connected w-ith the-base 53 so that:

upon movement ofthe piston-in the cylinder the base 5i3 is movedalong the guideway 6! toward or-awayfromthedie 29 depending upon the directionof movement of the pistoninthe cylinder.

Thepiston-is-operated by hydraulic means presently to be described. Hydraulic actuation of the die til relatively to the'die29 has very important advantages-over mechanical operation ofthe diesas mentioned aboveand as will be further developed below.

'Ihepiston rod 64 passes freely through a bore 64a in a bracket- 6417 l which is stationarily mountedon-the frame. Thepiston-rod 64 is threaded fora-portion of its --length and has two pairs of co-operating locknuts-84c and 6411; one pair'oneach side of the'bracket 64b.' The locknuts 64c limit' the movement of the piston inthe cylinder 63 when -the-die30 is retracted away from" the die 295 Thelocknuts 64o maybe adjusted to--difierent-positions when pipe of different diametersisbeing operated-uponsoas to desirably limit *the stroke of -the piston and eliminate unnecessary-lost 'motionr The locknuts 64d havenofuncti'on in normal operation of the apparatus but maybe usedtolimitthe-forward movement of the piston during setting up; alsothey serve as a safety device-to stopthe piston in the event of die breakagepr other emergency. In Figures 5; 6; '7 and 8 clearance is shown between 65 in the die till-(Figure 5) The flange and recess relatively fix ed axial position; Also, the radial dimensions-of the flange 34 and the recess 65 are proportionedsothat when the flange bottoms in the recess it limits the movement of the dies toward'each'other and hence limits the extent of the operation upon-the pipe. Thus I insure uni form and accurate thread formation.

3 Immediately behind-the flange 34 the die 29 has a radial recess fifi'against which two rollers- GT'bear to-counteract-the thrust against the die 29 ofthe die 30 when the latter is moved toward the former-w The thrust bearings 61 are mounted "60.U'in' a head 68 mountedon the machine frame and adjustable'toward and away from the dies by adjusting screws 69.

During operation-'of-the dies on the pipe the shaftBGturns in the-clockwise direction when 'viewed -from the 'rig'ht-hand'end thereof in Figure-5. Thus-the tendency of the die 29, as will be ob'servedbya consideration of Figure 5, is to turn' out ofthe end-of the-pipe orconversely-to back the pipe ofi-ofthe die- -29 during thread formation: 'To-counteract that tendency the'die 30 is made of somewhat greater diameter than the die 29 but the gearing isofnecessity arranged so that both dies-'turn at the same angular veloc ity-butin opposite directions. Thus during thread throughselongatedfislotsdilmn thessupport 49ston75srormation the die w not 'oIIIy'co Operates' withwiforlimited.-rtuming.movement v the -45 has other functions. It enters an annular recess arse -139 the die 29 to form threads in the pipe but also exerts a frictional force on the outside of the pipe tending to turn the pipe onto the die 29 and thence prevent it from backing ofi. Since the end of the pipe is disposed against the flange 34 during rolling of the threads it is maintained in fixed axial position relatively to the dies during the thread forming operation.

The gearing is enclosed within a casing lit. Disposed within the casing and connected with the shaft 43 by a coupling H is an oil pump 12 (Figure which picks up the lubricating oil from the bottom of the oil pan and delivers it through pipe (not shown) to the gears and bearings.

The shape of the dies is of great importance in the formation of my improved threads. One of the dies is a thread forming die while the other die is a non-thread forming die which co-operates with the thread forming die to cause the metal of the pipe to flow into the thread forming die. The dies have complementary metal forming faces, the thread forming die preferably having thereon a helical metal forming projection whose side walls are substantially parallel to each other and the non-thread forming die having thereon a helical metal forming projection whose side walls are inclined to each other, which inclined side walls extend substantially to the crest of the second mentioned projection, the projections being in axially staggered relation. The projections are shown to greatly enlarged scale in Figure 11. In that figure the thread forming die is the die 29 since it forms the threads on the inside of the box end of the pipe. The dies for operating on the pin end of the pipe are reversed, the thread forming die being the outside die. In Figure 11 the outside die 38 is a non-thread forming die. The helical metal forming projection of the thread forming die 2% is shown at 73 and the helical metal forming projection of the non-thread forming die 3%] is shown at M. The side walls 15 of the projection it are substantially parallel to each other while the side walls 16 of the projection M are inclined to each other and extend substantially to the crest l? of the projection '14. The projections i3 and 7d are in axially staggered relation. The inclined side walls it of the helical projection i l on the die 36 preferably have rounded corners "i8 and '19 at their top and bottom extremities respectively. The dimension of the projection M axially of the pipe at its crest is not over about half of the axial dimension of the projection 73. In between the convolutions of the projection is the face of the die 3!] has a helical groove lid of somewhat dished shape merging through the rounded corners 79 into the inclined walls '36 of the projection M. Since the axial dimension of the projection M at its crest is not over about half the axial dimension of the thread forming projection 73 of the die 29 the groove 88 is of substantially greater axial dimension than the projection '13.

The end face 8| of the helical thread forming projection 73 is shown as being substantially at right angles to the side walls l5 so that the thread forming projection ":3 is substantially square as shown in Figure 11. The dies co-operate so that in the threaded pipe the thinnest section at the thread is at least about eighty per cent of the thickness of the pipe wall at a point removed from the thread. I

The improved results obtained by my improved dies are realized to the fullest extent through the hydraulic actuation of the dies toward each other. Hydraulic actuation plus the shape of the dies resuits in formation of a thread greatly superior to rolled threads heretofore produced.

As the outer die 3i} moves toward the inner die 29 and engages the outer surface of the pipe it first deforms or corrugates the pipe so that in its initial stages the pipe is wavy internally and externally like corrugated iron culvert pipe. This corrugation of the pipe results in its being foreshortened, i. e., in its length being somewhat decreased. As the pipe is foreshortened the piston in the cylinder l4 moves forward due to the constant hydraulic pressure which i applied to it so that during the foreshortening process the box end of the pipe is at all times maintained firmly against the flange 34. The foreshortening and corrugating process may continue for a number of revolutions, say twenty, until the inner faces of the corrugations engage the bottom of the groove between the convolutions of the thread forming projection '13. At that time the hydraulic pressure on the die allows for commencement of flow of the metal of the pipe without shearing of the metal. The non-thread forming projection M with its inclined faces and rounded corners causes the metal of the pipe to flow somewhat axially along the groove between the convolutions of the thread forming projection 73 to fill the corners of the groove and thus produce a square cornered thread. Continued hydraulic pressure consolidates and solidifies the metal so that a strong compact metallic structure results.

During the thread formation the metal is squeezed so that it is caused to flow without any substantial shearing to form threads projecting from one surface of the pipe while the opposite surface is deformed; thus the metal throughout the entire thickness of the pipe is flowed and reshaped during thread formation. The metal flow is limited at the crests of the incipient threads and the metal is forced laterally generally parallel to the crests to form the generally square thread corners.

Figure 10 shows a joint between two sections of pipe having threads rolled thereinto in accordance with my invention. The section 82 has an internally threaded box end 83 and the section 84 has an externally threaded pin end 85. The internal threads in the box end and the external threads in the pin end are of substantially the same form except that the internal threads face inwardly and the external threads face outwardly. Since the threads are substantially square they interfit very accurately and provide the maximum resistance to pulling out. Also, due to the form and proportions of the threaded pipe ends as above explained, the joint is exceptionally strong in tension tests to failure.

The thread proportions and dimensions are determined by the dies and are, of course, the same as the proportions and dimensions of the dies. The surface of the pipe opposite the thread. has a helical depression Whose dimension axially of the pipe at its bottom is not over about half the dimension of the thread axially of the pipe and the depression is disposed radially opposite the center of the thread crest. A helical projection is disposed radially opposite the thread throat. The projection and depression merge into each other through rounded corners. The helical projection opposite the thread throat has a dimension axially of the pipe at least one-third greater than the dimension axially of the pipe of the thread throat. The side walls of the helical depression opposite the thread crest are inclined toward each. other and extend substantially to removed :from they thread.;

The operating and controlling mechanism is 7 shown in- Figure 4; The oil tank forthehydraulic actuating mechanismis shownxat 86.1 The; pump for placing the oil for thehydraulic vcyline. I ders under pressureis-shown at 8 1. Oil 'isdrawn out of the tank-86through a1pipe-88-andis ide livered from the pump 81through-apressureline 89 towae way valve 9lli'having a valve operating:

The valve may beof conventional-forma Whenthe die-30 is to be moved toward the'die- 29 the valve 90-is operated so that thefliiiddrom the pressure line 89 passes through a -pipe-92 to the outer end of the: cylinder 63 to push thepiston in that cylinder in the upward direction'view ing Figure 5; The fluid in front ozf the piston- J to-a'T 94 in a pipe 95:- A one-way=-valve-96:permits flow-of fluid only-from right toleftand not from left to rightin the pipe 95 viewing-Figure.

4. Therefore, the fluid passing downwardly lever ,9 l

passes out ofthecylinder-63 through a-pipe 93 through the pipe-934s constrained to move to the left in the pipe 95.

The pipe 95 delivers-the fluid-to a flow-controlling throttle valve-S] having an adjustment device fifi; for controlling the opening therein so thata-desired amount of throttling of the :fluid:

passing tothe valve 91 through the pipe-95qmay be obtained- Fluid leaving the .valve 91 passes through a-pipe I and baclginto. the :tank -86. Thus the throttle valve 91 is effective tothrottle or slowdown, the flow of fluidirom in front-20f the-piston in the cylinder 63 ,when; the die :3flviS being moved toward the die 29.; By a-proper setting of thetvalve 91 thedesired speed ofrmovement of the die 30 toward the-die 29 may-,beobtained so as to bring about the proper metal ,flowg. However, the-hydraulic system is such that when the die fifluis withdrawn away from the=idiew29 the throttle valve 91 does not :function so that thespeed of withdrawal may begrapid-and;;in dependentofthe speed of advance. Whemthe die 30 ;is-to ;be withdrawn awayjrom the :die :29 the valve Qiiris moved to the-,position inzzwhich thefluid under pressure from the pipe 89 passes out of the valve through the'pipe 'lfll and thence through thexone-way valve-flfiinto-the Ti94. Due to the throttling effect of the valve 9'! the .fluid pass s pw y h u h hespipe 93 and'iintc the-cylinder at th ide oi thezpistonznearest the die 30. The fluid fromtthe sidehof the piston remote from the die 30*passes outof the cylinder through the pipe 92 through the 4-way valve flfl andvbackto the pipe- I 00=through a pipe I02.

There is provided a source :of compressed air which, passes through apipe--'=l'03"-to a valve 104 controlled by a treadle I05. Depending upon the position of the treadle the valve l 04 may direct the air under pressure through either of two pipes I 06 and I01. Those pipes lead through pipes I08 and H19 respectively to the lower and upper ends of the cylinders 22 so that by operation of the treadle I the actuating members I! are operated. Only one of the cylinders 22 is shown in Figure 4 but the pipes I06 and ID! are connected with both of such cylinders in like The source of compressed air is connected through a pipe H0 with a hand operated valve Ill so that the compressed air may be delivered through either of two pipes H2 and H3. Those pipes lead to the respective ends of the cylinder 114 llisotthat tdepeadine :upcmthe apositiom frthee valve 1H icompressedairimayvmoyetherpiston-im the cylinder: 1 4 :in:eitherrdirection; The zfunction accomplished: by-.- their movement: has: 811-, ready beerrexplainedza.

The. shatt :36emay-fibe driven: through the. 5 .0013: pling. 3B yby: an electric; motor .1Msthrough.,.a; suitable. gean reducer. Theepumpltilrmay her operated byaan electriclmotoneither on-thesames shaft or; gearedr togthe pump: shaft; l llectricalv energy may be delivered to 1 a switch :box: 1 I52; through wires not shown) passing through nan;- inlet conduit I it; and to the respective motors through. conduits .l l l :and through; :a;- conduit :1 .l 8 to control switches: H 9::- Theaelectrical control system1may=.be-'conventional.:

tau-pipe 'GXldviSHtO' bezthreaded ithesdie 130.: is :movedaway: from: thie.=.dier29;- awpipe end is; introduced over the die 29 :as; above explained,i. the dies and pipe @are rotated and .1 during ,suchz-v rotation the die 30 wis:moved::against theioutsides: of the. pipe end: opposite: die; 29 :as above; explained to roll threadsintothe pipeend. When; the thread-ing has been completed. the die Bitmapbe :retracted and the apipeoslowed Cup: 1 relatively-'- to: the die- 29 manuallymr otherwiserwhereupon the threaded pipe automatically backs off of :the; die 29. This is a rapid way of removing: as: threaded pipe irom the die: If desired-ztheirotation of thed-i'es may bestopped'and thepipe mayo be-turned off of 'the di'e 29. Thecdiiesumaygblee rotating or stationary whenathe apipe. end-11s price sentedthereto prior tos three.ding:-

My metal pipe-having agroiled thread is claimed;

: in'my divisional-application Serial 18!);828;

filed October 12, 1950.

While'I have shown and describ'ed;present:

preferred embodiments of invention and: a.-.;

present pref erred method of-practicing the same;

it is to be distinctly understood that the .invene tion is not limited thereto-"but may be otherwise 1 variously embodied and": practiced 1 within the; scope of the foll'owing :clairnssv I claim:

1. In-a machine for rolling-threads intoi metal: pipe, a-rotary die adaptedto be'posi-tioned' insidex a pipe end, the die being mountedhfor-rotationw about afixed axis, a second -rotary'v-die adapted to be positioned outsidethe-pipeend; a 'support: in which the second -die is mounted a base ;on which the support is pivotally mounted, the base being movablegenerallytoward and away from the first mentioned die; and means for maintai-m ing the support in: desired angularposition-aboutits pivotal mounting; on the-base:

2; In a machine for'rolling threads intometalpipe, a rotary .dieadapted ,to be ppsitionedinside apipe end, the diebeingmounted 'for rotation" about a fixed axis; a second rotary di'e'adapted to be positioned outside the pipe end, a support in which the second die is mounted, a base on which the support is pivotally mounted, hydraulic means for moving the base toward and away from the first mentioned die, means for maintaining the support in desired angular position about its pivotal mounting on the base and means for adjustably positioning the base relatively to the hydraulic means in the direction of movement of the base.

3. In a machine for rolling threads into metal pipe, opposed rotary dies having complementary metal forming peripheries, one of said peripheries having thereon a helical metal forming projection comprising a plurality of convolutions having in axial cross-section a substantially flat crest extending generally parallel to the axis of the die and substantially fiat side walls substantially perpendicular to said substantially flat crest forming a depression between adjacent convolutions of the projection, the bottom of said depression being substantially flat in axial cross-section and extending generally parallel to the axis of the die and joining the side walls of adjacent convolutions of the projection, and the other of said peripheries having thereon a helical metal forming projection comprising a plurality of convolutions directly opposed to the helical depression of the first mentioned periphery, the helical metal forming projection of the second mentioned periphery having in axial cross-section an elongated substantially fiat crest extending generally parallel to the axis of the die whose dimension axially of the die is not over about half the dimension of the depression of the first mentioned periphery axially of the die and outwardly inclined side walls with rounded corners at the top and bottom extremities of the side walls, said elongated crest being of sufficient length to force the metal of the pipe into said first mentioned depression and against the bottom thereof and the side walls being so related as to create axial flow of said metal to fill the corners of said first mentioned depression.

4. In a machine for rolling threads into metal pipe, rotary complementarily threaded dies adapted respectively to be positioned inside and outside a pipe end when the pipe end is presented thereto and to cooperatively roll threads into the pipe end, means for supporting said dies so that the outer end of the inside die is unsupported to permit the pipe end to be introduced endwise thereover, the inside die having a radial flange located inwardly of the threads thereof at a predetermined distance and spaced from the unsupported outer end thereof acting as a stop to limit the extent to which the pipe end passes over the inside die and thereby determine the location of the threads in the pipe, and the outside die having a radial groove receiving the radial flange of the inside die to maintain the dies in relatively fixed axial .position during formation of the threads in the pipe.

5. In a machine for rolling threads into metal pipe, rotary complementarily threaded dies adapted respectively to be positioned inside and outside a pipe end when the pipe end is presented thereto and to cooperatively roll threads into the pipe end, means for supporting said dies so that the outer end of the inside die is unsupported to permit the pipe end to be introduced endwise thereover, means acting on the outside die to move that die transversely of its axis toward the inside die, the inside die having a radial flange located inwardly of the threads thereof at a predetermined distance and spaced -from the unsupported outer end thereof actin as a stop to limit the extent to which the pipe end passes over the inside die and thereby determine the location of the threads in the pipe, and the outside die having a radial groove receiving the radial flange of the inside die to maintain the dies in relatively fixed axial position during formation of the threads in the pipe, the radial dimensions of the flange and groove being proportioned so that the flange bottoms in the grooves upon predetermined movement of the outside die toward the inside die whereby to limit the extent of action of the dies on the pipe, and roller means acting against the portion of the inside die at the side of the flange thereof remote from the outer end of the inside die and remote from the outside die supporting the inside die against bending caused by the action of the means for moving the outside die toward the inside die and thereby minimizing deflection of the inside die during rolling of threads in the pipe end to effectuate the limiting effect of said flange and groove.

HARRY J. FINCH.

References Cited in the file of this patent UNITED STATES PATENTS N umber Name Date Re. 9,908 Blakeslee Oct. 25, 1831 9,732 Muntz June 14, 1853 326,516 Pierce Sept. 15, 1885 350,853 Anderson Oct. 12, 1886 421,625 Sims Feb. 18, 1690 509,730 Grifiin Nov. 28, 1893 748,276 Gabriel Dec. 29, 1903 768,771 Riegner Aug. 30, 1904 798,448 Pogany et a1. Aug. 29, 1905 859,642 Cummings July 9, 1907 1,033,568 Fell July 23, 1912 1,330,316 Hall Feb. 10, 1920 1,544,057 Dimick June 30, 1925 1,804,686 Hall May 21, 1931 1,936,401 Lovely Nov. 21, 1933 2,054,182 Unke Sept. 15, 1936 2,122,525 Huntsman July 5, 1938 2,145,587 Draper Jan. 31, 1939 2,182,401 Kreis Dec. 5, 1939 2,312,225 Wilkinson Feb. 23, 1943 2,352,726 Maulding July 4, 1944 2,365,820 Hibbard Dec. 26, 1944 2,405,141 Hibbard Aug. 6, 1946 2,610,532 I-Ieppenstall Sept. 16, 1952 FOREIGN PATENTS Number Country Date 12,373 Great Britain 1848 28,465 Great Britain Apr. 25, 1907 893,456 France July 28, 1944

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