US2642113A - Apparatus for straightening pipe - Google Patents

Description

June 16, 1953 T. H. KENNEDY ETAL 2,642,113

APPARATUS FOR STRAIGHTENING PIPE Filed June 16, 1948 2 Sheets-Sheet 1 Elli-i1 16 10b J 15 INVENTOR.

TRUMAN H. KENNEDY BY AND SAMUEL. WEBB a ATTORNE Y J1me 1953 T. H. KENNEDY ET AL 2,642,113

APPARATUS FOR STRAIGHTENING PIPE INVENTOR. TRUMAN H. KENNEDY AND SAMUEL WEBB f owla /dd% ATTORNEY Patented June 16, 1953 .2; 3. 1..

7 2,642,113 I APPARATUS FOR STRAIGHTENING PIPE Truman H. Kennedy, E

gheny County, and

to United States Steel Cor- Hills,.Pa., assignors lizabeth Township, Alle- Samuel Webb, Pleasant poration, a corporation ofNew Jersey ApplicationJune 16, 1948, Serial No. 33,358

' .2 Claims. (c1. 153-48) v This invention relates to the manufacture of pipe and, in particular, to an apparatus for straightening pipe without subjecting it to excessive cold work or introducing sufficient ovality as to affect the physical properties, specifically the collapse strength.

Seamless pipe as now produced is finally straightened cold, largely by passing it through a straightener including spaced pairs of cross 7 rolls and a bending roll therebetween. The

cross rolls rotate the pipe on its axis by friction and feed it axially. The forces applied may be great enough to cold work the pipe or produce a slight degree of ovality therein which together materially affect the physical properties, such as the collapse strength. 1 This seriously impairs the quality of the pipe for certain uses, such as well casing wherethe maximum collapse strength is desired. In fact, straightening as now performed largely wipes out the effect of certain processing steps intended to, increase the collapse strength. As a result, a gag press has been resorted to for straightening but this is a slow, tedious operation requiring considerable skill.

We have invented a novel apparatus for straightening pipe which overcomes the afore-v mentioned objections to the prior practice. The object of our invention is to provide an apparatus for straightening pipe continuously at high speed without cold-working it enough to reduce its physical properties. 'A further object is to provide an apparatus which is simple and easy to operate and a-method which may be readily integrated into present mill procedure without introducing any difficulty or slowing down production. In a preferred practice, we advance the pipe axially while turning it on its own' axis and subject it repeatedly to a momentary-transverse bending force applied in accordance with a predetermined space-time relationship to the travel of the pipe. Specifically, weapply the force successively to points spaced symmetrically I around the-circumference of the pipe, a predetermined number of times for a given axial travel of the pipe. -The apparatus we employ is generally similar to the ordinary cross-roll straightener but includes important features of novelty which adapt it for carrying out our method. We also bend the extreme ends of the pipe while the intermediate portion is held firmly gripped in order to remove hooks. A complete understandingof the invention may be obtained from the following detailed description and explanation which. refer tothe accompanying drawingsrillustrating a preferred embodiment and practice. slnthe drawings,

the relative location of Figure l is a diagrammatic plan view showin the cross rolls for rotating and turning the pipe and the bending rolls cooperating therewith;

Figure 2 is a similar plan view, likewise somewhat diagrammatic, showing mechanism for actuating the bending rolls into effective position and withdrawing them therefrom, the main framework of the apparatus being omitted;

Figure 3 is a transverse section on the plane of line III-III of Figure 2, through the idler roll of one of the pairs of cross rolls;

Figures 4 and 5 are diagrams showing the distribution in lengths of pipe. of two different sizes of the points at which bending force is momentarily applied; and

Figure 6 is an end view of a modified form of bending roll.

Referring in detail to the drawings, and, for the present to Figure 1, spaced pairs of cross rolls in and Il, including driven rolls l0 and H and idler rolls lo and H are disposed in the known manner so as to rotate a pipe length P about its own axis by frictional contact and, at the same time, feed it axially in the direction of the arrow, the cross rolls l0 being adjacent the entering end of the straightener and the cross rolls l l adjacent the exit end.

A bending roll I2 is mounted between the two pairs-of cross rolls for movement into and out of engagement with the pipe, as indicated by the positions shown in dotted and solid lines, respectively. Hook-removing rolls [3 and M are similarly mounted adjacent the entrance and exit ends of the machine for temporary engagement with the extreme ends of a length of pipe, the roll 14 serving to engage the leading end of the length. and the roll [3, the trailing end, when actuated to the dotted line position. It will be understood that the rolls of each pair I0 and H are skewed oppositely. The rolls [2, l3 andv M are likewise skewed in the same direction as the idler rolls lo and H. The idler rolls, as shown in Figure 3, comprise a solid core 15 of metal having acontinuous sheath of rubber-like material It therearound. This sheath affords the friction necessary to rotate the pipe without adjusting the rolls of each pair to exert such pressure thereon as to introduce ovality into the pipe.

Referring now to Figure 2 showing the means for driving the rolls III and H and adjusting the rolls l2, l3 and M in greater detail, it will be noted that a lineshaft I'l drives the roll W through bevel pinions l8. Similarly, the shaft 11 drives-the roll ,ll, through bevel pinions 30,

Guide shoes 2| and 22 are disposed between the rolls of each pair I and H. The idler rolls l and I I are journaled in bearing yokes 23 mounted in a suitable supporting frame for adjustment to and from the driven rolls and l I with which they cooperate.

Each of the bending rolls l2, l3 and [4' is similarly journaled in a, bearing yoke 24 mounted for reciprocating movement toward and from the line of travel of the pipe P. Conveniently, the main supporting frame may be provided with ways (not shown) along which the yokes 24 are slidable. ward and away from the line of travelof the pipe by a pitman 25 pivoted thereto and .to a crank 25. The bearing yokes 25 have spaced lugs 2'1 drilled to accommodate a wrist pin 28 which passes through the pitman 25. The .crank 26 is operated by a motor 29 having a built-in gear reducer 39. In Figure 2, the rolls l2, l3 and M are shown in their retracted positions corresponding to the solid line positions of Figure 1. They do not, therefore, engage a pipe length as the latter is introduced first between the rolls l0 and 16 and then between the rolls H and H.

As soon as the entering pipe length is frictionally engaged by the rolls Ill and [9 of course. it is rotated about its own axis and fed axially over the guides 2| and 22. When the leading end has been engaged by therolls ll" and l 1 the motor 29 actuating the roll I2 is started. Continuous operation of the motorcauses a bending force to b applied at spaced intervals transversely of the. pipe between the rolls Hi and I l which constitute abutments aifording the necessary reaction to the bending force exerted by the r011 12. The motor 29 operates continuously while the pipe length is traversing the machine and' thus exerts its bending force momentarily at points spaced circumferentially and longitudinally of the length, once for each revolution of crank 26.

We have found that, for good results, the points at which bending force is applied should. be symmetrically spaced circumferentially of the pipe. In addition, the force should be applied to a complete series of three, four or six points about the circumference in each successive four-foot portion of the length or thereabout. This may be best explained by reference to Figures 4 and 5. Figure 4 shows the location of four points, a, b, c and d, at which the bending pressure is applied to a 4 0. D. pipe-in a 3' 10" length thereof. It will be observed that the points'are spaced 90 apart around the circumference of the pipe. They are spaced apart longitudinally about 2%; revolutions of the pipe which travels 3' 10" in the nine revolutions required to complete the entire cycle of four applications of vbendingpressure. 7

Figure 5 demonstrates a similar but somewhat altered practice applicable to 8%" O. D. pipe. Here the points of successive application of the bending pressure are designated, as in Figure i, and are spaced 90 apart circumferentially of the pipe. Because of the larger size 'of the pipe, however, only five revolutions thereof are necessary to move the pipe axially the distance covered by a complete cycle which comes out 4 1". The points of application of the bending pressure may be 60 or 120 apart, instead of 90. There would then be six or three points of application in each approximate four-foot portion of the pipe length.

The actuation of the roll [2 toward and from Each bearing yoke is actuated to the pipe to apply bending pressure at points spaced apart by the desired angles circumferentially and the desired distance longitudinally may easily be controlled by varying the speed of motor 29 so as to correlate it with the rotation of thepipe and its axial travel. The rotation of the pipe, of course, depends on the speed at which the rolls Ill and ll are driven and the axial travel of the pipe depends on the angle of skew at which the rolls of each pair [0 and I I are set relative to each other.

As theleading end of the pipe length emerges from betweenthe rolls of pair II, the bending roll 14 is advanced into operating position by energizingits motor 29. In case the pipe length has ahook at the end, which is the usual condition, engagement thereof by the roll M as the pipe rotates and the hooked end oscillates about the mathematical axis, straightens the bent portion and leaves it accurately aligned with the intermediate portion. The roll I4 is left in its advanced position only while the first eight inches or so of the pipe length are traveling past it, after which the roll is retracted and remains out of the Way until the leading end of the succeeding length approaches.

' The roll I3 is actuated in precisely the same manner to straighten the trailing end of the pipe length by removing any hook therefrom. In

other words, the roll I3 is advanced into engagement with the pipe at a point about eight inches from itsextreme trailing end and is retracted when the end has passed. The engagement of the rolls [3 and M with the pipe is continuous and not intermittent, as in the case of the roll I2. Instead of employing the crank and pitman for advancing and-retracting. the bending rolls, we may employ any equivalent'mechanical device, such as cams, toggles or hydraulic cylinders. Instead of bodily advancing and retracting the bending roll l2, we may employ an eccentric roll or a roll having an eccentric or built-up portion at one point onits periphery. Either of these expedients serves in the same manner as already explained to exert bending pressure on the pipe at points spaced circumferentially and longitudinally as it rotates and travels axially through the machine. Figure 6 shows a bending roll IZT having a shaft 3| which is eccentric relative to the body thereof.

' We have found that, by causing the bending roll l2 to engage the pipe intermittently, the pressure which must necessarily be exerted by the cross rolls on the pipe to rotate it by frictional engagement is not so great as to effect coldworking or introduce ovality into the pipe to such extent as to impair its physical properties. This result is also aided by the use of rubber sleeves on the idler rolls "l and li The'invention thus permits pipe to be straightened as rapidly as is possible with a conventional straightener, without reducing its physical properties, such as collapse strength, whichhas been a. necessary concomitant of the. use of conventional straighteningmachines. In addition, we are able to remove hooked ends which are frequently encountered, thus leaving the pipe precisely straight throughout its entire length. The method of .our inven-" tion may readily be integrated with the conventional procedure formaking seamless tubing continuously, without increasing the difiiculty .thereof or slowing down production. .JOur apparatus,

furthermore, involves only a slight increase over.

the cost of a conventional straightener and its 5 operation does not require any more skill than the latter.

Although we have illustrated and described but a preferred embodiment and practice of our invention, it will be recognized that changes in the details and procedure disclosed may be made without departing from the spirit of the invention or the scope of the appended claims,

We claim:

1. In a pipe straightener, two pairs of cross rolls in tandem adapted to turn a pipe on its axis while advancing it axially therebetween, a bending roll between said pairs of cross rolls and skewed similarly to one of the latter, a second bending roll beyond one pair of cross rolls and means for continuously advancing the bending rolls into engagement with the pipe and retracting them therefrom at a predetermined frequency.

2. In a pipe straightener, two pairs of cross rolls in tandem adapted to turn a pipe on its axis 20 while advancing it axially therebetween, a bending roll between said pairs of cross rolls and skewed similarly to one of the latteryand means for continuously advancing the bending roll into engagement with the pipe and retracting it therefrom at a predetermined frequency.

TRUMAN H. KENNEDY. SAMUEL WEBB.

References Cited in the file 01 this patent UNITED STATES PATENTS Number 15 Number r 29,023 303,790 38,779 507,933

Name Date Robertson Mar. 31, 1874 McCool Jan. 1, 1889 Muncaster Oct. 3, 1899 Muncaster Oct. 1, 1912 Sleeper Apr. 3, 1917 Wise May 12, 1931 Hartley Nov 1'7, 1931 Urschel Apr. 26, 1938 Huston Sept. 20, 1938 FOREIGN PATENTS Country Date Germany Oct. 21, 1884 Germany Feb. 15, 1918 Switzerland Apr. 1, 1921 Germany Sept. 22, 1930

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