DE1652598A1 - Device for pipe drawing - Google Patents

Description

H 521

Dr -in ·: - .. '.ANS RUSCHKH

Dip! -Üiq. HEINZAGULAR

Munich 27, Pieewww «Stt <.a.

North. American Rockwell Corporation, El Segundo / Oalifornia (USA)

Device for pulling the ear

The invention relates to the thinning of the walls of workpieces with circular cross-sections and in particular to a "method and a device for thinning ßohrwandungen using several adjustable roller shapes The present invention is also related to the invention disclosed in the German patent application N 28 777 in relation C

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The general method for the symmetrical deformation of the walls of pipes is known from the American patent _{specification Sr 0} 2 432 566.If the forming rollers are perpendicular to the axis of the pipe, as is common practice, the circular contact between the forming rollers and the outside of the pipe creates a seam that the pipe will be bent or crushed. To avoid this difficulty, mandrels are commonly inserted into the tube, but the process is costly and limits the range of extraction that can be performed. A similar arrangement for pulling out pipes is disclosed in US Pat.

In order to facilitate the deformation of the pipe, the pipe should be put under tension. While in most cases the tensile forces exerted on the pipe depend on the speed at which the pipe is drawn through a series of dies more complicated arrangements have been developed for this purpose. However, none of these new arrangements could provide constant tension. Is the train changeable and not determinable in advance, a breakage or rupture of the pipe may occur not easily avoided, so the pulling speed must be reduced so that the pipes can be withdrawn safely. Such a decrease in the pulling speed however, it can be a significant limitation. The use of shapes with contoured surfaces according to the American Patent Ur · 3 240 045, with a surface contact with the pipe which leads to strong friction, so that the pulling speed is slow. In this procedure there is also the risk of the pipe rupturing, stretching excessively, or

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forms a neck due to the extremely heavy load near the tailstock. As in the German above Patent application N 28 572 executed, several adjustable forming rollers can be aligned so that their axes are transverse to the axis of the tubular workpiece. However, these forming rolls have a cylindrical outside, with several disadvantages which are eliminated by the invention, as will be described in detail later

The invention provides a drill pulling device with a clamping device which contains several Yorm rollers, which at the same time are adjustable and constantly thinning the walls of a tubular workpiece. The forming rollers are with the jig connected so that their axes have a fixed inclination with respect to the pipe axis, which is preferably is between 35 and 55 °. The peripheral parts of the forming rollers, which rest on the drilling rolling, are concave, so that contact with the tube along a helical line will be produced.

If the forming rollers and the pipe are rotated with respect to one another, with this arrangement there is a uniform distribution the load along the helical zontact line with the lowest torque, so that pressing in and compression of the pipe in the longitudinal direction is essentially avoided will. When the tube is pulled into the mold, a constant tensile force is exerted by a device that does not act on the acts on the tapered end of the tube.

The invention also provides a method of pulling out of pipes using a jig, which has multiple adjustable and radially aligned forming rolls with a

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having concave outside, which method is characterized is that the forming rollers are arranged in such a way that their axes form an angle of 35 - 55 ° with the axis of the pipe, that the forming rollers with the pipe run along a helical line Have continuous line existing contact, and that a relative rotational and longitudinal movement between the forming rollers and the Pipe is produced for pulling out the pipe. The invention will now be described in detail.

In the accompanying drawings the

Fig.1 is a schematic representation of a lathe with the Clamping device of the forming roll arrangement according to the invention,

Fig. 2 is a diagrammatic representation of the clamping device and forming roll assembly according to the invention with certain parts cut away to show in which Way a helical contact is established between the forming rolls and the pipe, Fig.3 is a plan view showing the inclination of a single

The forming roller shows the pipe to be pulled out, FIG. 4 shows a diagrammatic representation of a pipe section,

which is drawn thinner, and the helical contact, Fig. 5 a diagrammatic representation of the individual parts of a

Clamping device according to the invention, 6 shows a diagrammatic representation of components of the

Clamping device according to Figure 5, Figure 7 is a diagrammatic representation of the individual parts of another embodiment of the clamping device,

8 shows a longitudinal section through a tapered pipe section, Fig.8a is a cross section through the tapered part of a

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Pipe according to the line 8a-8a in Fig <> 8, Fig. 8b is a cross-section through the non-tapered part of the

Hohres along line 8b-8b in Figo8, and the Fig. 9 is a schematic representation of a device which exerts a constant tension on the pipe to be tapered.

The Figure 1 shows a schematic representation of a lathe 10, in which the device can be used according to the invention _e The lathe 10 has the typical bed 12 with the guides 13, on which a carriage is slidably supported 16 may »The carriage 16 be moved on the guides 13 ζ .Bo by a conventional and not shown tension spindle, which is driven by a suitable, not shown motor at different speeds. A clamping device 20 is attached to the slide 16 and carries a plurality of forming roller blocks 24. As will be described later, the special relationship between the jig 20 and the forming roll blocks 24 is a feature of the invention _o An elongated tube 26 is passed through the center of the jig 20, which is to be drawn thinner The jig 20 moves parallel to the axis of the tube 26 in a direction indicated by the arrow T (FIG. 2).

During the thinning process, the rear end 28 of the tube 26 is held in place, while the front end 27 is kept in place a movable device 29 which is to be described and which exercises a train is connected. The entity making a move 29 pulls on the end 27 as the tube 26 is continuously elongated so that there is a constant uniaxial tensile force on the tube 26 is exercised. When the clamping or pulling device 20 tapered across the tube 26 in the direction T from the «■

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End 28 moved from the non-tapered end 27, so the pulling device 20 rotated with respect to the tube 26

To control the desired tapering of the tube 26, a conventional template 30 is provided which determines the movements of the standard roller blocks 24. The template 30 is involved a follower element 32 which is connected to a valve 34, which valve is connected to a cylinder 40 via lines 36 and 37 communicates. The follower member 32 is pressed against the template 30 by a spring. Depending on the pressure medium, ) either through lines 36 or 37 to the opposite one Sides of the piston 41 is passed, the piston rod 42 sets the ScV ^ .itten 44 in motion accordingly. An arrangement of limbs 35 coordinates the movement of the piston rod 42 with the valve 34. The carriage or slide frame 44 is related to the carriage 16 mounted movably on these and provided with a transverse arm 45. This arm 45 is fastened to a collar 47, which in turn has an actuating tube 48 via a bearing (not shown) is connected that rotates with the pull assembly 20. With the reciprocating movement of the operating tube 48, the forming roll blocks are 24 actuated and moved back and forth in the direction of the tube 26.

Many components of the lathe 10 and the means for controlling the movements of the puller 20 are commercially available and are therefore not described further. In the preferred embodiment of the invention, the pulling device rotates 20 around the tube 26 and is advanced along the axis of the tube ^ 6. Within the scope of the invention, the tube 26 can also be used in parts of the headstock and tailstock (not shown) of the lathe 10 stored and pulled rotating by a stationary pulling device. All that is required is that between the

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Eohr 26 and the pulling device 20 a relative rotary and longitudinal movement he follows.

The Pie.2 shows the pulling device 20 and the associated Form roll blocks 24. The drawing device 20 has a general circular housing 50 with a through-hole 51 in the middle on » through which the tube 26 and the actuating tube 48 extend coaxially. The housing 50 is equiangularly spaced provided with the radially extending guides 52, in which the forming roller blocks 24 are slidably supported with the aid of the T-sections 56 are. During the ear pulling, the pulling device 20 is in the Direction T moved forward, the blocks 24 at the same time in relation on the tube 26 inwardly or outwardly.

Two arms 69 are attached to each of the inner ends 68 of the three forming roller blocks 24. Between every two arms 69, a forming roll 70 is supported at opposite ends in conventional roller bearings 72. The forming rollers 70 have the same outline, are polished and can be made from graphitic * Are made of molybdenum steel. Shall be the tube drawing in cryogenic environments are performed, the forming rollers 70 can be made of tungsten carbide. The particular one used for the forming rollers Material does not form part of the invention.

An important feature of the invention is the angle θ between the axes of the forming rolls 70 and the longitudinal axis of the pipe 26 (Fig. 3) as long as the angle Q is within a range that allows helical contact between the circumference of the forming orphans 70 and the pipe to be extracted results are unexpectedly good. Fig. 3 shows a rope of a single forming roller 70, the axis of which crosses the axis of the pipe 26.

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rotated while advancing in the direction T, with a deformation of the ear 26 takes place at the transition part 26d. The forming roller 70 has a wider front end 70b and a narrower rear end 70a as well as a central part 70c » This part 70c is concave and continues in a somewhat convex shoulder 70s at the end 70b. The forming rollers 70 can on the other hand also have the shape of an hourglass, in which case the forming rollers are wider at both ends than in the middle be. The contour of the forming rollers 70 is chosen so that there is helical contact between the roller and the tube 26 is produced, which in Fig * 4 at H in the deformation zone 26d is shown.

If the angle Q is less than 20 °, the pipe becomes unstable and, under certain circumstances, bent. This can be useful for certain purposes if, for example, for ornamental purposes, polyhedral tubes with helically extending surfaces are desired. It has been found that the best results are obtained when the angle θ is between 55 and 55 °. Within this range, the helical contact H shown in FIG. 4 is the most favorable and is characterized by a composite curve. It is known that the tapered ends of an egg are more resistant to pressure than the side parts. The same applies to the deformation forces which are exerted by the forming rollers 70 on the wall of the tube 26. If the angle Q is smaller than 35 ° and is gradually decreased, the helical contact gradually becomes a straight line contact, with the risk of the pipe being squeezed. It is the same case as when the point of application of force is shifted from the tip to the sides of an egg. If the angle Q exceeds 35 °

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is increased, the helical contact becomes more pronounced at least within a range, the maximum value of the angle Q being approximately 55 °.

At an angle 0 of 35 ° or less in the form of rollers 70 cause the tube is polyhedral. Furthermore, the sliding friction is increased in this area, so that there is a risk that the pipe walls will tear. The resulting approximately straight force distribution in this area can lead to bending or crushing of the pipe. At an angle θ exceeding 55 °, too great a tensile force is exerted by the pulling device on the tapered part 28 of the pipe 26, which can lead to the pipe being pulled out too much, since the tensile strength of the pipe material is exceeded. If the angle exceeds 0 , the forces exerted by the forming rollers concentrate on a narrowly delimited point, with the risk that the tube 26 will be pressed in. According to the invention, the dangers mentioned are essentially avoided in that a helical contact is established between the forming rollers 70 and the tube 26. Under these conditions there is a minimum torque between the forming rolls 70 and the tube 26, which minimizes the scraping, rubbing and hardening which can lead to the formation of cracks on the outside of the tube , and a pipe with a thinner wall can also be manufactured. The highest pulling speed can be achieved when the angle θ is between 35 and.

The Pi «.5 shows a special pulling device 20, where the longitudinal movement of the actuating tube 48 can be pivoted over three

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mounted actuators 71 is transmitted, which the Pormwalzenblock blocks 24, of which only one block is shown, move radially at the same time. The actuators 71 are on the inner wall parts a housing portion 50 attached, which with the help of the bolts 53 on the remaining parts of the not shown Housing can be releasably attached.

As can be seen from the Pig. 6, the front end is of the actuating tube 48 is provided with a head 80 on which three transverse slots 82 are provided at equal intervals are. Each actuating member 71 has a rounded inner edge 74, which sits in a slot 82, and an outer edge 76, which rests in a slot 84 on a jaw portion 54 of the block 24 is provided. The actuating member 71 is mounted pivotably on a pin 72 in the housing 50 (Pig. 5). Every transverse Pin 72 is in a not shown bore in the housing 50 is used, which bore runs perpendicular to a radial line in the housing section 50. Will the actuation tube moved forward in the direction of the Pormwalzen 71, so the

76 inner edge 74 pivoted forward, since the outer edge is upwards is pressed. During this upward movement of the outer edge 76, the associated jaw 54 is displaced radially outward. Here If the Pormwalzen are further removed from each other and produce a bore taper with a larger diameter. on the other hand the actuators 71 are in a backward movement in the opposite sighting pivoted, with the outer edges 76 push the associated jaws 54 radially inwards so that the orphans 70 produce a tapered pipe wall with a smaller diameter.

The Pig 7 shows another embodiment of a pulling device

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device 20 having a generally frusto-conical actuator 80, which is provided in the middle with an opening 82 through which a tubular workpiece, not shown, during its machining is passed through. The actuating member 80 is connected to the actuating tube 48 by means of screws 83, which extend through Openings 87 of a flange 89 on the actuating tube 48 extend through and screwed into each of the respective bores 86 on the actuating member 80 will. The actuator 80 is equally spaced with three slots 84 having a T-shaped cross section which form inclined slide ramps 85. On each cheek part

54 is a cam member 92 having a T-shaped cam portion attached, which is inserted into a slot 84. When the actuating tube 48 moves forward, the actuating member 80 moved forward with ramp 85 at the cam section 94 slides along and pushes the jaw 54 radially outward. When the actuator tube 48 is withdrawn, the jaws 54 withdrawn inwards at the same time. Pure experts are still Further designs of an arrangement are obvious in which the standard I-rollers 70 can be moved at the same time.

In order to allow taper tube and make the tube-shaped workpiece more easily deformable, the workpiece 26 is biased by the invention In some cases, the conventional arrangements are satisfactory, in which a pipe is clamped by static weights. With these arrangements, however, no constant tension can be exerted on the pipe · If the pipe is exposed to the action of variable or unpredictable forces, there is a risk of the pipe rupturing. With the device 29 shown in Pi <t »1, a predetermined constant tension is to be exerted on the pipe. In practice

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the tube 26 is preloaded with a predetermined tensile force which slightly exceeds the elastic limit of the metal which the pipe 26 consists. In this case permanent deformation is caused.

FIG. 8 shows a longitudinal section of a tube 26, while FIGS. 8a and 8b show the cross sections of the tapered part 28 and the non-tapered part 27. If the tube 26 is kept under tension, then in the ideal case A ₂ χ SY ₂ = A ₁ χ SY ₁ , where

A _{1 is} the cross section of the non-extended pipe part 27 A _{2 is} the cross section of the extended pipe part 28

SY _{1 is} the tension slightly above the elastic limit of the non-extended pipe part 27

SY _{2 is} the stress below the final elastic limit of the extended pipe part 28

If the exerted force A ₂ χ SY _{2 is} greater than A ^ χ SY ₁ , a thinner wall is produced in the tube 26 than if the two forces are equal to one another. Conversely, if the force A ₂ x SY _{2 is} less than the force A ₁ χ SY ₁ , then a relatively thicker wall is created in the pipe to be tapered than in the case of equal forces. These different tapering conditions can be determined by a corresponding dimensioning of the angle θ (Fig * 3). If the angle θ is increased from 55 ° to 90 °, the torque between the pulling device and the pipe 26 is also increased at the same time. The associated increased load on the pipe part 28 then leads to a thinning of the wall of the pipe 26. If the increased tensile load on the tapered part 28 exceeds the elastic limit, this leads to

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a necking of the pipe. It should be noted that ever The harder a metal becomes as a result of machining, the higher the ultimate elastic limit becomes · »Some metals such as Inconel X, for example hardens very quickly when machined, while grade 304 stainless steel hardens slowly when machined. The harder A metal becomes through machining, the more the metal can absorb an increased load without reaching the ultimate elastic limit is exceeded. These facts must be taken into account when carrying out the method according to the invention will.

The method according to the invention can be used with a slight modification when the metal of the pipe has the most favorable ductility at temperatures higher or lower than the ambient temperature. Ζ · Β · titanium has a low ductility at ambient temperature and hardens very quickly during machining, so that the titanium tears very easily under the action of relatively weak forces. The method according to the invention could be applied to a pipe made of titanium if the pipe is heated ^{to 205 to 425 0 O by means of a suitable resistance heater.} This will roughly double the ductility of the pipe. If the ductility of a metal, for example stainless steel of the type 304, is increased at temperatures below the ambient temperature, a cryogenic fluid could be passed through the pipe 26.

FIG. 9 shows a schematic representation of a Train exerting device 29. The non-tapered end 27 of a tube 26 is clamped in a clamping device 104, which with a slidable support 106 is connected, which in turn with

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the piston rod 110 of a hydraulic cylinder 112 is connected is. The piston rod 110 carries a conventional piston 111, the slidably mounted in the cylinder 112, which cylinder is the chambers 1 * 4 and 115 with a variable volume. The piston 111 is from a pump arrangement HO with the twin centrifugal pumps 14-4 and 145 actuated, which are arranged in a housing 141. The pump assembly 140 pumps pressurized fluid from a Reservoir 142 in cylinder 112, being between the chambers 114 and 115 maintain a constant different pressure. ^ is obtained, which is used to apply a constant to the pipe 26 under its static and dynamic conditions exercise train.

While the tube is being pulled out, the piston 110 closes the tube 26 at any time. off and compensates automatically the axial extension of the pipe. As the tube 26 becomes longer axially, the length exerted on the piston rod 110 changes Pull from a measuring instrument attached to the piston rod SG is determined. This measuring instrument SG is represented by a variable resistor R, which is inserted into a Wheatstone bridge WB is switched on. Before starting to pull out the pipe, the resistance R, is set to a predetermined value Set value that corresponds to the desired tensile force that is to be exerted on the tube 26. This tensile force is said to be the yield point slightly exceed the pipe material. If the pipe 26 becomes longer, the piston rod 1fO thus displaces liquid from the chamber 114, whereby the pressure is increased. At the same time, the pressure in the chamber 115, which is determined by the measuring instrument SG, is reduced. The tension exerted on the tube 26 is therefore reduced below the desired value. The resulting change in electrical

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Resistance in the resistance element IL caused in the Wheatstone bridge a Uhbalance «To restore the desired voltage in your 26 the Whetstone Bridge WB must be brought back into balance.

This is done by the pump arrangement HO. to for this purpose, the pump 144 with the intermeshing gears 146, 147 and the punvoe 145 with the intermeshing Gears 148, 149 are provided. The individual gears rotate in the sense indicated by the arrows. A pump cavity 151 is designed so that the clearance between the individual gears and the surrounding wall the arrangement of a Labyrinth seal allows. In this arrangement, pressure fluid is enclosed between the teeth of the individual gears and conveyed up into conduits 155 and 157. The liquid enters the cavity 151 through the openings 151 and 153 which are in communication with the reservoir 142. the Pipe 155 is in communication with chamber 114 and pipe 157 with chamber 115.

The movement of the liquid through conduits 155 and 157 is controlled by an electromagnet 120 operated by the Wheatstone Bridge WB is powered when the There is an imbalance in the bridge. The electromagnet 120 has a coil 121, which has a bearing 122 with a double balance valve 124 is connected. The valve assembly 124 has two valve members 129 and 128, with which the connection between the Pipeline 155 and the reservoir 142 as well as between this and the pipeline 157 can be closed.

During the pauses in pulling the pipe, the equilibrium of the Wheatstone bridge WB is restored. the

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Coil 121 of the electromagnet is in the neutral position, in which the valves 128 and 129 are open to the same extent. The pressure difference in cylinder 112 is then constant. Arises however, in the Wheatstone Bridge WB an imbalance as a result of the Circumstances that the Spannunc in the pipe 26 has become smaller than the preset value, the coil 121 of the electromagnet is moved to the right, at the same time the valve 128 is closed and the valve 129 is opened so that the pressure in the line is decreased and the pressure in the line 157 is increased. To this During this time, the valve 129 acts as an overflow valve, so that liquid is drained from the line 155 into the storage container 142. When the pressure in chamber 115 has risen to a value at which the previous pressure difference between chambers 115 and 114 has been restored, the measuring instrument SGr a value sufficient to restore the balance of the Wheats tone bridge WB. The coil 121 of the electromagnet is then shifted to the left so that the valves 128 and 129 assume the same setting.

These processes repeat themselves constantly in the device 29 during the pipe drawing, so that the axial Strekune of the tube 26 is constantly compensated. With each axial partial extension of the tube 26, the piston rod 110 is shifted to the left, with the result that the Hess instrument SG is at the Wheatstone bridge WB causes an imbalance. As a result, the valve assembly 124 is actuated by the electromagnet 120 and thus the Pump assembly 140, the required pressure difference in Cylinder 112 is restored, the partial extension of the tube 26 being compensated.

It should be noted that the pump arrangement

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is stationary, and that the length of the bore of the cylinder 112 is always greater than the predetermined distance by which the tube 26 is stretched. Assuming that the forming rolls are like that are aligned so that the wall thickness of the tube remains constant before and after being pulled out, the piston rod 110 moves always to an extent determined by the percentage by which the diameter of the ear 26 is reduced. Takes place at the tube 26 has a $ 40 reduction in diameter so becomes the piston rod 110 moves four tenths as fast as the pulling speed amounts to. If the pulling speed is ZoB. 88.9 cm per minute, the piston rod 110 is moving at a speed withdrawn from 35.56 cm per minute.

The embodiments of the invention described above can be used by experts within the scope of the inventive concept Changes, modifications and replacements are made. The invention itself is therefore only defined by the appended claims delimited.

Pat ent calls

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Claims (8)

16S2598 '■ ■ - ".. ■■■ claims 1. Tube pulling device with a pulling device ', which has several jaws, with which several radially aligned iormwalzen are connected, and means for adjustable opening and closing of the forming rollers with respect to a tubular 7 / piece surrounded by them, and means that allow relative rotation - and ^ longitudinal movement between the drawing device and the tubular workpiece during extension effect, characterized in that ά * forming rolls on the other outer side are concave configured and so angeo dnet that their longitudinal axes extend transversely to the longitudinal axis of the tubular workpiece such that the during extension tubular workpiece, the forming rollers act on the workpiece along a helical contact line. 2. Device according to claim 1, characterized in that that the angle enclosed by the axes of the forming rollers and the axis of the workpiece is 35 to 55 °. 3. Device according to claim 1 or 2, characterized in that that three J-standard rollers are provided at equal intervals 4 · Device according to claim 1, 2 or 3, characterized by a device which acts on the tubular workpiece during exerts a predetermined constant pull when pulling out, BATH ORIGINAL - Ϊ9 - 5. device n-ach claim 4, characterized in that that the constant tension exerting device consists of a tension-sensitive element that the elongation of the to be rejuvenated workpiece determined, as well as a responsive to the tension-sensitive element device that the stretching automatically compensated 6. Device according to claim 5, characterized in that the device responding to the voltage-sensitive element has a cylinder and a piston which is in communication with the tubular workpiece via a piston rod and exercising a pull on this. 7. Device according to claim 6, characterized in that the tension-sensitive element consists of a tension meter which is electrically switched into a Wheateton bridge is that when an imbalance occurs, an actuation of the piston rod to restore the constant tension in the tubular workpiece 8. Device according to one of claims 1 to 7, characterized characterized in that the means for adjusting moving the > Forming rollers comprise an actuating tube which is in connection with the drawing device in which the tubular workpiece is located is located. 9. Device according to claim 8, characterized in that that the pulling device has a frustoconical and with the Actuating tube has connected cam shoe, which with a 109839/0265 Number of inclined cam slots is provided that with the jaws cam elements are connected, which are in the cam slots are slidably mounted, with an axial movement of the actuating tube a movement of the forming rollers with respect to the tubular Workpiece causes 1Oe device according to claim 9 »characterized in that that the cam slots and the squat elements have complementary T-shaped cross-sections. 11 · Device according to claim 8, characterized in that that the pulling device has a number of actuating cams with inner and outer cam edges that are attached to the pulling device are pivotably mounted, and that cam slots are provided on the actuating tube and on the jaws, which the inner and pick up outer cam edges. 12 method of pulling out an ear with a pulling device, which has a number of adjustable and radially aligned forming rollers which are concave on the outside are characterized in that the axes of the forming rollers are aligned so that they are below the axis of the pipe at an angle of 35 to 55 ° so that between the forming rollers and the ear there is contact along a spiral line is produced, and that a relative rotary and longitudinal movement between the forming rollers and the Eohr for the extraction of the pipe is effected * ORIGINAL INSPECTED 109839/0265 Blank page