US2589651A - Pipe bending machine, including skid lifting device - Google Patents

Description

March 18, 1952 s. l.. BALLARD PIPE BENDING MACHINE, INCLUDING SKID LIFTING DEVICE 7 Sheets-Sheet 1 Filed Oct. 5, 1950 50m L. Bcr//O'rd HVVENTUR.

BY n 6a March 18, 1952 l s. L. BALLARD 2,589,651

PIPE BENDING MACHINE, INCLUDING SKID LIFTING DEVICE Filed Oct. 5,\11950 7 SheeS-SheerI 2 L J2 N 55 W44 wm L. 5m/0rd INVENTOR.

ATTORNEYS s. l.. BALLARD 2,589,651

PIPE BENDING MACHINE, INCLUDING SKID LIFTING DEVICE March 18, 1952 '7 Sheets-Sheet 5 Filed Oct. 5, 1950 d m E wm MM HN O om n Bm MIA. L. m

March 18, 1952 s. L. BALLARD 2,589,651

PIPE BENDING MACHINE, INCLUDING SKID LIFTING DEVICE Filed Oct. 5, 1950 'TSheets-Sheet 4 wry.

Jam l... o//ard INVENTOR.

A TTOR/VEYS March 18, 19.52

s. l.. BALLARD PIPE BENDING MACHINE, INCLUDING SKID LIFTING DEVICE 7 Sheets-Sheet 5 Filed OCT.. 5, v195.50

Jom L. Bo//ord INVENTOR.

BY '3 @la/JQ -f M, fm Arron/vn;

March 18, 1952 s. L. BALLARD 2,589,651

PIPE BENDING MACHINE, INCLUDING SKID LIFTING DEVICE Filed Oct. 5, 1950 7 Sheets-Sheet 6 50m o//oro INVENTOR.

BY cfamffm (OMQOM ATTORNEYS March 18, 1952 s. L. BALLARD 2,589,651

PIPE BENDING MACHINE, INCLUDING SKID LIFTING DEVICE Filed Oct. 5, 1950 7 Sheets-Sheet 7 Jom L Bcr//ord INVENTOR.

ATTORNEYS Patented Mar. 18, 1952 TENT CFFICE PEBEEENDING MACHNE, INCLUDNG SKID LIFTING DEVICE .Sam L.'Ballard, Houston, Tex.

Applicationxctober 5, 1950; Serial No. 188,668

3 Claims. .1'

This application is af continuation-impart of my. co-pending application Serial Number 152,252, led March` 27,. 1950. It relates toa pipe Abending machine adapted to bend pipe vertically upward; itfalso relates to, a -pipe bend-ingmachine adapted tobend pipe` against a, fixed `die as a fulcrumby actuating ,a strongbackto move the pipe iinto the Xed-.dieandfto apply a bending force to one end off the pipe while the pipe is held on the opposite side of the ixed: die from said bending force by a holding shoe; and it also relates to the employ-- ment of` cable and pulley means to move the strongback tov bend the pipe. It alsorrelates to pipe bending machine, as described hereinabove, which have self-contained therewith 4means forv lifting the skid end of the machine when'the machine is to be transported.

vIt is an objectief this inventionto providea pipebending machineY having a iixedl die as a bending fulcrum to receive an upper portion of the pipe, a, holding shoe spaced from theI xed die to receive va lowerl pipe portion, and astrongback suspended below the fixed die and underextending the fixed die opposite the holding lshoe and-adapted tomovethe pipe upwardly-into the xed die, and to have bending iorceapplied to the underextend-ing portion to` bend` the pipe.

Itl isa further object of Athis inventiontof provide a: pipe bending; machine having .-a'xed dieasa bending fulcrum,aholdingshoespacedfrom theiixed die, and a strongback positionedparallel tothe i'lXed'V dieand-extending ybeyond the fixed dieopposite the holding shoe, .and cable means adapted ter move the strongback tocarry vpipe thereinV against the iixed die, -and.to move the` extending strong-back portion to bend the pipe around the fixed diefas afulcrum while the-shoe holds the pipe.

It is another object of this invention to pro'- vide a machine of this class in which the strong-'- back is moved by a driven drum-actuated cable loops extending onv either-side of the frameY over bending pulleys on the framer and extending strongback end, fulcrum pulleys on'theestrongbackY and frame adjacent thevinner die-end, 'and snubbing pulleys on the frame Aand strongback end adjacent the outer die end; the vloop being completed below the strongback ybetween the snubbing pulleys.

It is still another object of this. invention to provide a machine of this class in which the strongback is moved by a driven drum actuated cable'loop extending on either side of theframe over bending pulleyson theframe and .extending strongback end,i and fulcrurn pulleys on the 2 frame and strongbacirv end adjacent the diegpthe loop being completed below the strongback` between the fulcrum pulleys.

It is still a, further object of thisinvention to provide a machine of thisclasshaving a holding shoe which may be adjusted. and locked. to hold successive sections of bent pipe moved; thereinto, and which shoe has, means thereonto protect the pipe from being marred by the shoen while unlocked duringl adjustment.

It is yet a further object of this invention to provide a pipe bending machine of' this, class which is equipped with liners for the-strongback and holding shoe to convertthese elements, to, accommodatel pipe of lesser than the 'maximumv diameter for which the machine is designedgfand which has rollers on either endof thestrongback vertically adjustable to permit'variousfdiameter pipe to be loaded over the strongback'when in lowered position, the inner roller. complementing stop means on the other end of thestrongback to position the lowered strongback.

It is still a further object of. this' inventionv tov provide a pipe bending machine of 'this'elass having cablev ends. maintained to. eXtend parallel from flange separated'. driven drum'sections into contactwith spacer pulley sheavesjmounted'.' on a spring connected ybracket pivotedj to'theframe.

It is yet another vobject, of this `inventiorrto provide a pipe bending machine 'of-this "class equipped with meansjthereon forhan'dlingthe.

pipe to be bent, as by successively loadingk portions of pipe into `the machine.

It is still a further object ,ofthis invention. to,

provide a pipe bending machine of this classjhaving a power means, as an engine thereon.' orj'actuating the cable winch, with a, platformA adjacent thereto from which an operatorLmay control engine and winch.

Itis also an object of this'inventionl to' provide a pipe bending machine of'this class havingl a.

a pipe bending machine of this class having a fixed die with bed radially curved upwardly and toward the bending end of the machine, and also having the radially extending side surfaces of the die adjacent the bed curved upwardly and toward the bending end of the machine, but curved with such a radius of curvature as to permit the strongback side surfaces to contact, and roll along, the side surfaces of the die during the bending operation.

It is an additional object of this invention to provide a pipe bending machine of this class which has, as a part thereof, means for lifting its skid end above its base level so that it may be more easily transported.

It is a further object of this invention to provide a pipe bending machine of this class which may employ its pipe bending apparatus to lift its skid end.

It is yet another object of this invention to provide a pipe bending machine of this class which may lift its skid end at the same time that it bends pipe.

Other and further objects will be obvious when the specification is considered in connection with the drawings in which:

Fig. 1 is a side elevation of one modification of the machine taken along line I-I of Fig. 3.

Fig. 2 is a fragmentary, partially diagrammatic side elevation showing bending carried out by the machine of Fig. 1.

Fig. 3 is a plan view of a machine.

Fig. 4 is a sectional elevation taken along line 4-4 of Fig. 3.

Fig. 5 is a forward end View of a machine.

Fig. 6 is a diagram of the bending apparatus of the machine of Fig. 1.

Fig. 7 is a diagram of an optional bending apparatus.

Fig. 8 is a sectional elevation taken along line 8 8 of Fig. 9.

Fig. 9 is a sectional elevation through a lined die, shoe, or Strongback.

Fig. 10 is a side elevation from the opposite side of the machine shown in Fig. 1.

Fig. 11 is a diagrammatic view showing still another optional form of bending apparatus.

Fig. l2 is a plan view of a lifting beam as installed on a pipe bending machine.

Fig. 13 is an elevation of a lifting beam when installed on a pipe bending machine prior to lifting the skid thereof.

Fig. 14 is an elevation of a lifting beam when installed on a machine shown when the skid has been lifted.

Fig. 15 is an enlarged fragmentary elevation showing the strongback in rolling contact with the'fixed die.

Fig. 16 is an enlarged fragmentary elevation showing the fixed die relieved to avoid contact thereof by the strongback during the bending operation.

The pipe bending machine I has a frame 2 with the lower beams 3 thereof connected by means of the axle 4 to a supporting traction means, as the caterpillar 5 near the rear end of the frame, while the skids 'I support the forward end 8 0f the frame. The ring 9 is rrovided at this end 8 so that a connection maybe made to the machine, as when it may be desired to move it.

The uprights I I, slanted columns I2, and crossbraces I4 support the frame top beams I0 above the beams 3, and as shown in Fig. 3, cross-beams I5, I6, and Il cross-connect the beams III while 4 suitable corresponding members therebelow crossconnect the beams 3.

The power means, as a suitable internal combustion engine I8, is mounted on the frame top 2Q, and connected by the drive belt 2I to drive the winch 22. The winch 22 has two drum sections 23 and 24 separated by the anges 25, 26, and 2'?, and outwardly of the journal 28 for the shaft 29 it has a smaller diameter drum section 33 terminating outwardly in the end flange 3|.

The cable end 32 is connected to the drum section 23 adjacent the fiange 25 and the cable end 33 is connected to the drum section 24 adjacent the flange 26. From each drum the cable 35 extends over a pulley or pulley block 36 on the frame end 8 to the pulley 39 on the strongback 4c to a pulley 4I on the strongback to a pulley 42 thereabove on the frame 2 back to the pulley 4I and from thence to the pulley 43 on the strongback and up to the pulley 44 on the frame thereabove, and finally the cable extends under the strongback 40 to complete the loop 45 between the pulleys 44 on opposite sides of the frame 2.

The die or radially curved shoe 45 is removably fixed to the frame below the frame top 20 by means of the cap screws 41 which pass through the ange feet 48 and 49 of the cross-beams I5 and I6 respectively. The bed 5i] of the die is formed to receive substantially the upper semiperiphery of a pipe portion bent longitudinally to conform to the radius of curvature of the bed.

On the rear portion 6 of the frame 2, the eccentric shaft 5I, as shown most clearly in Fig. 4, is journalled in the longitudinally extending journal members 52 between the lower cross-beams 53 and in the journal bracket 54. This eccentric shaft 5I has the eccentric members 55 rigidly connected thereto to turn in the rings 56 which are rigidly connected to the holding shoe 6G.

On one side of the shoe Gil a ring 51 is provided and connected to the frame to extend around the shaft 5I. An arm 58 is rigidly connected to the shaft 5I adjacent to, and just outwardly of the ring 51. The arm 58 has the bearing lug 59 thereon and also the guide lug 6I. The pointed rod 62 slidably extends through these lugs 59 and 6l so that the point 63 may be partially inserted into the spaced radial holes E4 in the ring rim 65. A compression spring 66 is connected at 61 into the rod 62 and extends around the rod to bear against the lug 59 and to normally urge the rod S2 into the ring 5T. The handle 68 on the rod 62 is provided for lifting the rod from one hole 64 so that it may be spaced in another hole.

As demonstrated most clearly in Fig. 2, the shoe 6] has lugs 'II and 'I2 extending on either side thereof with the top sides 69 and E9 of these lugs being substantially parallel extensions of a horizontal plane through the lowest point of the bed 'IEB of the shoe Si?. Also, as shown in Fig. 2, the shoe is substantially straight and substantially shorter in length than the fixed die 45. The spring 73 is connected to the frame 2 at '14, as shown in Fig. 4, and to the inner end 'I5 of the shoe at 'i6 near the top thereof as shown in Fig. 3 and Fig. 4.

The rotation of the winch shaft 29 in a clockwise direction, as viewed from the right hand end of the shaft in Fig. 3, winds up the cable ends 32 and 33 on the drum sections 23 and 24 respectively. As shown in Fig. 2, after the cable has been actuated to raise the strongback Msoasito-liftthe-pipe 80 into contactr with the die 4E, further winding up of the cable bends' the-pipel intov the curvature of the die.

In order to insure that the cablewinds up evenly, thepulleysl 8| andl 82 are provided and mounted on the bracketv 83 with disc faces to extend in--a. horizontal plane; the bracket Varrn 84being pivoted at -85 on the cross-beam I-'l at the frame end 8. The cable 35 extends from the drum sections 3v and 24 into Contact with the innermost points of the pulley sheaves, the cablehend portions extending parallel toeach other a distance apart equal to the distance between the cable connections adjacent the iia-ngesy 25A and 26. This spacing tends to insure that the cable winds up evenly on the drum sections. K

Additionally, the spring 8G is connected to the bracket arm 84 at 81 and to the side of the frame at'BS tonormally pull the pulleys in the opposite direction from the direction in which the cable Winds up on the drum. This further insures that the cable does not jump about on the drum sections when the winch is rst started un.

In operation pipe may be leaded into the machine from either end, but is usually loaded in `from the forward end 8. To aid in positioning the pipe axially of the frame 2, the line 90 onV4 the vdrum section 3B is led over the guide pulley 9i on the top portion of the frame end 8 and extended around the pipe end and connected by means of the hook 92. The winch 22 isthen rotated to wind up the cable on the drrmV section 33 to draw the pipe 33 toward the machine I.

After the pipe 89 has been placed on the roller 93, it is guided into the frame over the strongback 40 with the strongback bed S4 lowered, as shown in Fig. 1, below the lowermost point 95- of the pipe periphery. To insure that the pipe enters the strongback fll the guide plates 96 are provided on either side of the strongback end 91. The line 9% is successively disconnected from the pipe 83 and moved outwardly thereon to be re-connected from time to time to assist the operation of loading-the pipe .into the-machine. If, for any reason it might be desirable to load pipe from the end S instead of the end 8, an arrangement similar to the guide pulley 9i might be installed. at some pointV on the end B outward of the winch 22, or optionally a separately driven winch might be installed on the end 8.

When the pipe has been loaded in over the strongback 4l) it makes contact with the vertically adjustable roller 98 at the opposite end ofA the strongback from the roller e3. In passingit ispointed out'that this roller S3 also acts as a positioning stop for the strongback when in lowered position to complement the lugV Sil-fof triangular cross-section fixed beneath the strongback which locates the strongback between the locating plates I S- on the forward partllof the frame 2.

lAfter the pipe 80 contacts the roller 98 it may be slid farther on through the machine and into the shoe 6B. As the spring 13 tilts the shoe 60 downwardly and inwardly when it is in unlocked position, the lower inner edge 'l5 of the shoebedr/is below the entering end oi' the pipe, so the pipe passes intothe shoe 6G without marringand delaying endto end contact between the" pipeandshoe.

When nallyiloadedandextending outwardly'- from the shoe... 80,. the pipe. isf'. seen?. in:v the position shown by dotted lines in Fig. 1. However, in;I this regard itwshould. be fconsideredl that?. the liner. H32, .shown finstalled. inithe. shoe;` 60 in Fig. 14 would be. omitted' to. receive; the. vpipe',` 80 so that'the pipa. of the largestdiameterfior which. fthe machine. has. been ,designed.. will. rest withini the; bed |93 of 'substantially 'semi-.peripheral. contour. of. lthe largestVv pipe :diameter:

The liners: 1.625 are designed: forzinstallatiorr :in the basic. beds: of the. holding shoe,'. andaof'"Y the strongback to. convertY these:` elements to receive pipe ofv smaller diameters. These liners: have .location pins4 or..dowels H39 thereontontxcorresponding .holes l lilv in thev liners. As shownzfin Fig. leach liner-forthe shoelllhas thelugsL-llll and lf2: thereon to correspond wththelugsfIl andi 'lZ on. the bed thereunder. The'topsides |13y and Hd ofi the. lugs I Il and lii2i.extend substantially parallel to th-e horizontalplane througlrthe lowesty pointof the liner. M2. The liner lugs. Hl and II2 have the bars IBI-welded. on eitherfside thereof to extend below andV alignthese lugsz'with the shoe lugs 'H and l2.

With the pipe loaded, the operatoren thepla-tform. |041 actuates the bendingV operation, the platform being located sothatthe operator can reach the engine clutch |35, the gear shift, 1.06,. the winch hand; clutch lill', andthe winch foot brake 108, aswell .as any other engineorwinch controls and brakes, not shown.`

It can be presumed that forxordinary: bending by'verticalmachines of this class,` that .broadly six essential elementsare required, namely, a"

frame, a Viixed radial Vdie supported fron-inthe frame top with bed downwardly, a holdingshoe spaced longitudinally of the frame from theii'lxed die with bedupwardly, a strongback .suspendable with bed upwardly suiiiciently. beneath the 'fixed die to permit pipe to be loaded between the xedy die and holding. shoe and underextencling the xed die in a directiontherefrom opposite -the holding shoe, a means to lift the strongback-with pipe therein upwardly to bring the pipe into contact with the xed die, and a means to pull upwardly near the outer end of the strongb-ack to bend the pipe into the curved bed of the nxed die while the rst means holds up the opposite end portion of the strongback to maintain vthe pipe therein against the xed: die bed While the holding shoe anchors the pipe portion therein against downward motion asfthe pipe. is bent.

However, when a pipe bending machine is considered which must bend a wide variety of. ranges in both w-all thickness, piper material and. temper, and diameter, it often happens'that a ma.- chine designed to bend thick walled pipe has to be modied to bend thin walled pipe. Also, when it is considered that in certain usages of pipe, as in buried pipe lines which are processed externally against corrosion and other factors,` and which are subjected internally to excessiveuid pressures, pipe must be employed which is free of bulges and wrinkles, it can be seen that a delicate control must be provided to bend thin walled pipe without bulging or wrlnkling its sur face.

In the type .of machineshown in Figs. 1, 2,and 6, the bending means employed Vconsists of the pulleys 36 and 39 which may be termed the -pulling or bending block; the pulleys 4| Iand 62, which may betermed the squeezingk orfulcrum block; andthe pulleys 44. and c3 which may be termed the snubbing or Wrinklecontrol block. More generically; theA combination of pul1'eys"4`|`,"42, "44,

and 43 may be termed the .squeezing or fulcrum block.

When the winch 22 is first rotated, the pulleys 4|, 42, 44, and 43 remain in the vertical plane positions of Fig. 1 as the strongback 4|! is lifted upwardly to bring the pipe 80 into contact with the die 46 at the end |5 of its periphery. After this contact is established the strongback begins to bend the pipe into the xed die and the point of greatest application of the bending moment moves successively upward and to the right along the bed 50 of the die, as shown 'in Figs. 1 and 2.

When contact between die and pipe has first been established and bending begins, the increased tension on the cable 35 taughtens the cable throughout its length and this increase causes the cable, to move to the right, as nal slack is taken up. Then, as the strongback 4i] is pulled upwardly toward the right, the cable between pulleys 43 Vand 4| can be observed to move slowly to the left as the distance between pulleys 44 and 43 increases faster than the distance between pulleys 42 and 4| decreases.

The bending force increas-es as the strongback approaches the end of its upward travel to the right, since, in any one gear, the R P. M. of the winch remains constant, and consequently the bending moment remains constant. As a result, the bending force increases as the bending radius or arm decreases. At this point the upwardly curved radially extending sides |35 of the fixed die 46 should be noticed, as this feature prevents interference with the strongback. As the point of application of the bending moment moves constantly to the right, as shown in Fig. 2, and toward the pulley 39 on the underextending end of the strongback, the downward pivoting of the pulley 43 with the strongback end H6 opens out the distance between pulleys 44 and 43. This increased cable length is drawn from the right of pulley 43, as explained hereinabove, and in opposition to the pull to the right which the winch exerts to bend the pipe.

Then, since the strongback is not completely rigid, but has a certain flexibility therein, the pull of the winch, which resists the spread between pulleys 44 and 43, tends to wrap the slight- 1y flexible strongback against the pipe to the left of the theoretical point of application of the bending moment, thereby spreading the area of bending, and protecting the thin walled pipe from the wrinkling which otherwise often occurs due to the application of an excessive moment in a Very localized area.

As successive lengths or portions of pipe are bent, the pipe is handled by the line 90, or by any other conventional handling means, as from an A-frame on the top 20 of the frame 2, or by a tractor on the ground in front of the machine and is moved rearwardly through the frame 2 and shoe 6l). When this is done, the shoe 6|) is unlocked until the next adjustment is completed.

During the positioning of the pipe in the shoe, and when it is unlocked, the pipe may tend to bind at some point in the bed of the shoe, with the result that the shoe may tilt and tend to bring either one or the other edge of the shoe into :biting contact with the pipe. The lugs 1| and i2 on the shoe 6|) are provided to avoid this as the top sides 69 and 69 of these lugs pivot upwardly, dependent on the direction of tilt, to contact the under side of the pipe. In cases Where the shoe is lined, the lugs and V|| 2 on the liner |02 serve the same purpose, as the top sides ||3 and ||4 will contact the pipe, dependent upon the tilt.

When the pipe has been shifted, an operator lifts the handle 68 of the rod 62 against the pressure of the spring 66 and places the rod point 63 in the rim hole 64 corresponding to the higher tilted position of the shoe 65. The pipe is then ln position for the next portion in the die to be bent.

The bracket |26 of the caterpillar 5 is trunnioned at |2| on the axle 4, and has the trunnion pins |22 at either end upon which the wheels |23 are mounted to rotate. The caterpillar track |24 is belted about the wheels |23 to supply the rear traction contact. Other traction devices, as wheels, may be employed in place of the caterpillar.

This invention is not limited to a machine having the cable and pulley arrangements hereinabove described, but any other arrangement operable on the holding shoe-fixed die-movable strongback principle is considered, as that shown in Fig. 7. In such an arrangement the winch 22 on the frame 2 has the cable 35 thereon which l extends on each side of the frame, over a pulley 36 on the frame top 2i) to a pulley 39 on the strongback 40, to a pulley |3| on the strongback below the fixed die 46, up to the pulley |32 on the frame adjacent the fixed die 46, back to the pulley |3l, up again to the pulley, |32, and under the strongback 43 to complete the loop of the Cable between the pulleys |32.

lThis arrangement is most applicable to machines for bending thick Walled pipe, as such is not likely to wrinkle or buckle when an excessive bending moment may be applied at a very localized point. In such arrangement the pulley |32 is best located on the fixed die at some point relatively intermediate the pulleys 44 and I42 as shown in Figs. l and 2.

As shown in Fig. ll, the arrangement of Fig. 7 may be connected to be actuated by two separately controlled Winches 22 and |35. In this case the winch 22 has the cable 35 extending therefrom over the pulley |32 on the frame adjacent the xed die 46 and preferably centrally thereof, downwardly to the pulley I3| on the strongback 40, upwardly again to the pulley |32, and downwardly under the strongback 40 to complete the loop between the pulleys |32.

The Winch |35 has the cable |36 extending therefrom to the pulley 36 on the frame end 8, then downwardly to the pulley 39 on the strongback 43, upwardly to the pulley 36, and then downwardly under the strongback 4i) to complete the loop between the pulleys 36. When two Winches are thus employed it is obvious that the number of cables on the bending end is greater between -pulleys than on the squeezing or fulcrurn end. It is also obvious that the independently operated Winches should be synchronized, at least by co-operation between the two operators of the winches.

The arrangement of Fig. 6 can also be connected to be driven by two separately controlled Winches. not shown in the drawings. In such case the Winch 22 has cables extending therefrom on either side of the frame to the squeezing or fulcrum pulley 42 on the frame adjacent to the' forward part of the die 46, and from this pulley the course of Fig. 6 between the pulleys 42, 4|,

Y 43, and 44 is followed. The cable path from the forward winch is the same as hereinabove described for the arrangement of Fig. 11.

This arrangement, being obvious, isn

Throughout the description, the path of the .cable betweenpulleys has been broadly discussed without giving consideration to the reeving of the pulley sheaves. Obviously, this invention lis not limited .to any specic number of cables, it being pointed out only that preferably a greater number of cables should be required between the vpulleys 36 .and 39 at the point the pulling force of the winch is applied to the bending arm of the strongback. For instance, in the arrangement of Fig. 6 there are, on each side, ve cables -between the pulling or bending pulleys, four cables between the fulcrum pulleys, and four cables between the snubbing pulleys.

It has been stated that the radially extending sides |65 of the fixed die i6 are upwardly curved to prevent interference with the strongback 46 during the bending operation. Fig. 16 shows this feature in enlarged detail and accentuates the curvature of the die to show that there is no contact with the strongback at any point during bending. This is a desirable feature for the ordinary wall thicknesses of pipe, and for pipe of conventional hardness, as with such pipe it is desirable to employ the total force of the cables to roll the strongback along the pipe.

However, in some cases, illustrated by Fig. 1 5, with pipe of certain wall thickness, and of certain hardness, there may be danger of wrinkling the pipe should the full force, of the strongback be applied directly to bend the pipe. In such cases, the side surfaces |65v of the xeddie 46 are relieved along a radius of curvature which parallels the curvature of the die bed 56. The spacing is such that the strongback 46, will first move the pipe into constraining contact with the Xed die 46, and then, as further force is applied, the slight compression of the substantial semiperiphery of the pipe in the strongback responsive to this further force, will permit the strongback sides |66 to contact the dies surfaces |65' to limit further compression of the semiperiphery.

The extent of compression has to be relatively minute or the pipe will wrinkle, and therefore the distance the strongback moves after it forces the pipe into the die bed 5Fl until it contacts the die surfaces |65 is a minute distancemeasurable in fractions of an inch. From this point of contact the strongback sides |66 roll along the die sides |65' and the bending force is divided between the frictional force expended in effecting this rolling contact, and the force going to bend the pipe.

When a proper relationship exists, the compression of the pipe by the strongback prior to i establishing contact with the die |65', will tend to thicken-the pipe wall in the strongback and kthereby counteract the natural stretch of the outer semi-periphery of pipe from the center of curvature.

This invention includes both the construction shown in Fig. and that shown in Fig. 16. The `latter construction, in which the strongback rolls along the pipe, has a more universal application, however, since the bending force may be controlled, even in bending pliable, thin walled pipe, especially when the pulley arrangement of Fig. 6 is employed. However, the other pulley arrangements may be employed as well with the construction of Fig. 16, and pipe may be bent without the safeguard of a surface contact between strongback sides |56 and die surfaces |65.

In this resnect itis pointed out that the con- `struction of Fig. 15 has special applications, and u certain typesof pipe. This safeguard is obtained 'by'the'addition of another variable -to the bending combination in the nature of the spacing of the die surfaces |65 Within fractional limits.

,Pipe `,bending machines of the y type hereinabcveidescribed as well as other machines which have one end supported by skidsl 'I and the other end supported by a traction means-as byAa caterpillar 5 may be equipped to lift their-skid ends, .as shown in Figs. 12-14.

A-beam Il@ comprising two spaced apart, 'parallel extending rnerrxbersl |'|I and Vmembers |12 converging therefrom Vto a connection member H3, has the sleeves IM thereon, `through which extends .theaxle |15 vbetween the -skids 1. lGussets V6 may be provided to reinforce the sleeves im vand'the'1r i enf1bers lll and |12. Cross-braces it?? and |13 are also provided-tatie together the members |71.

Rings H9 are provided -at the Vinner 'ends' of the' members VH into which are connected means, suchas chains "|36, which may connect the beam ends to the strongback 40, as at'the ring ii. The connection member |13 has the opening |32 into which may be connected the hook vH33 of a prime mover, not shown, such as a tractor or anyother vehicle adapted toA pull a heavy machine.

After machines of the heavy nature ofthe pipe bending machines shown hereinabove, have settled in operation, the skids may become 'bogged iin, so that it maytask the ordinaryprime -mover tolocsen them to start them in motion. Also, even with the; skids resting on -a smooth surface,

.a considerableinitial force is required to overcome the inertia thereof.

With a machine equipped as hereinabove described, thehook i8'3 may be connected into the `ring i152, so that the outer beam end `may be supported kalcove skid base level, as bythe Vprime mover to which the hook |83 extends. Then the chains mi) may be connected at |8| to the strongback liti. Upon actuation of the winch 22, the strongbackiii'moves upwardly to contact the iii/red diet and then pivotsat the xed die and moves further upwardly at Yits end which is connected to the innerbeam end. The inner beam end is thereby lifted upwardly as'the sleeves |14 of the beam pivot rotationally on the axle |15 ,and Aas the outer beam end is supported above skid base level. This obviates overcoming the inertia of `theslrids by the forward motion of the prime mover, asit previously vtransfers lthe machine to be supported by thelprimemoverimeans at its forward end, and byits rear end support, as the caterpillar 5.

In cases where it may be desirable -to ibend a section of pipe and then leave it in the machine to be transportedythe pipe section may be loaded into the machine and strongback, and the chains I8@ connected to the strongback, so that the operation .which completes the .operation of bending the pipe will also lif-t the skid end. of ftheimachine. Y

'The theory of the beam lift applies -to machines other than pipe bending machines of the type described. The strongback, or equivalent, in such machines need not roll `upon a curved. die, but may be lifted up against a stop member, as a horizontal bar across the machine, and the inner end of the strongback equivalent may pivot against such bar Aas the outer end is moved 'further upwardly. In effect, this invention. includes any means @which will move the Y 11 inner beam end upwardly with relation to the top of the frame of the machine, while the outer beam end is supported above skid base level by external means.

Broadly, therefore, this invention includes any type of machine adapted to lift its skid end by lifting the inner end of a beam pivoted at the skid end while the outer end of the beam is sup- A ported above skid base level.

This invention also broadly considers a vertical pipe bending machine in which a downwardly facing fixed die acts as a fulcrum, an upwardly facing shoe holds the pipe at one end of the frame, and an upwardly facing strongback is moved to place the pipe in the xed die and then is moved upwardly, near the frame end opposite the holding shoe, to bend the pipe.

This invention also broadly considers a pipe bending machine in which a strongback is rocked -against pipe in a longitudinally curved fixed construction. For instance, whereas the ring 51 is shown xed to the frame this ring optionally might be iixedY to the side of the holding shoe and equally satisfactory results obtained. In such case the only difference in operation would rest in the fact that the ring would be substantially concentric with the center of the eccentric 55 rather than concentric with the axis of the shaft I.

In this speciiication it has been stated hereinabove that the strongback and holding shoe are equipped to have liners installed therein. mention has been made of installing liners in the fixed die as in practice it has been found more convenient to provide and install a fixed die 46 for each diameter of pipe to be bent rather than to line a basic fixed die of largest diameter veach time a smaller diameter of pipe is being bent. However, this practice is optional and the provision of liners in a basic die might be advantageous under certain conditions.

What is claimed is:

l. In a pipe bending machine, the combination of, a frame, means supporting said frame for movement including, a first support means connected to one end of said frame and a second v applying means for bending a pipe section, and

means for connecting the other end of said beam to said force applying means whereby the actuation of said force applying means will lift said rst support means by causing said beam struc- 12 ture to pivot about said pivot means when said connection means is caused to bear upon a support means as aforesaid.

2. In a pipe bending machine, the combination of, a frame, means supporting said frame for movement including, a nrst support means connected to one end of said frame and a second support means connected to said frame and spaced from said first support means, pivot means mounted on said frame above the level of the base of said first support means and adjacent said nrst support means, a beam structure pivotally mounted on said pivot means with an end thereof extending outwardly from said pivot means beyond said frame, connection means on said outwardly extending end of said beam structure designed to bear upon a support carried by a traction device, a pipe bending mechanism mounted on said frame and including, a force applying means for bending a pipe section, and means for connecting the other end of said beam to said force applying means whereby the actuation of said force applying means will lift said first support means by causing said beam structure to pivot about said pivot means when said connection means is caused to bear upon a support means as aforesaid, said pipe bending mechanism including, a curved bending die anchored to said frame and having a bend forming face portion, a holding shoe mounted in opposed relation to said die and adjacent one end of said die, a separate, independently mounted straight bending shoe having a part extending toward said holding shoe past the central point of the face of, and -directly opposing said bend forming face portion of said die and a part extending beyond said bend forming face portion in a direction away from said holding shoe, said bending shoe being free to move toward and from said die, said force applying means being adapted to urge a part of said bending shoe directly toward said die to substantially and tightly embrace a pipe held therebetween and to roll said bending shoe along said.

pipe.

3. In a pipe bending machine, the combination of, a frame, means supporting said frame for movement including, a rst support means connected t6 one end of said frame and a second support means connected to said frame and spaced from said rst support means, pivot means Y mounted on said frame above the level of the base of said first support means and adjacent said nrst support means, a beam structure pivotally mounted on said pivot means with an end thereof extending outwardly from said pvot means beyond said frame, connection means on said outwardly extending end of said beam structure designed to bear upon a support carried by a traction device, a pipe bending mechanism mounted on said frame and including, a force applying means for bending a pipe section, and means for connecting the other end of said beam to said'force applying means whereby the actuation of said force applying means will lift said first supportmeans by causing said beam structure to pivot about said pivot means when said connection means is caused to bear upon a support means as aforesaid, said pipe bending mechanism including, a curved bending die anchored to said frame and having a bend forming face portion, a holding shoe mounted in opposed relation to said die and adjacent one end of said die, a separate, independently mounted straight bending shoe below said die and having a part extending toward said holding shoe past the central 13 14 point of the face of, and directly opposing said REFERENCES CITED bend forming face portion of said die and a part eXtonding beyond said bend forming foce portion The following references are of record in the in a direction away from said holding shoe, said me 0f this partent: bending shoe being free to be moved upwardly 5 toward, and downwardly from, said die, said force UNITED STATES PATENTS applying means being adapted to urge a part of Number Name Date said bending shoe directly toward said die to sub- 1,530,261 Hawes Mar. 1'7, 1925 stantially and tightly embrace a pipe held there- 1,662,131 SChOneld Mal'. 13, 1928 between and to roll said bending shoe along said 10 1,741,840 Harmon et al DGC- 31, 1929 pipe. 1,943,594 Flatley June 16, 1934 SAM L, BALLARD 2,546,531 VultZ T Mar. 27, 1951

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