DE2051087A1 - Method for feeding round workpieces that rotate about their longitudinal axis during processing to processing machines, in particular straightening machines - Google Patents

Description

Th. Kieserling & Albrecht October 16, 1970 Solingen. ■ Tat.Abt.Koe / Huck / Bch patent application file K 159

Method for feeding round workpieces that rotate around their longitudinal axis during machining Processing machines, in particular cutting machines.

The invention relates to a method of feeding round workpieces that rotate around their longitudinal axis during processing to form processing machines, especially straightening machines in which the .. workpieces by means of driven hyperbole rollers, the are adjustable against each other and their inclination- I

v / inkel is adjustable, fed to the processing machine will.

The aim of the invention is to increase the performance of straightening machines, in particular, in that the V / piece pieces fed one after the other to the straightening machine pass through the straightening rollers without any gaps. Here, there is the further important advantage that the running out of the leveling rolls .Enden the ..erkstücke not be as deformed so far · This deformation of the "erkstückenden arises from the fact that when the workpieces through a distance the directional orphans," the is greater * than the support length of the workpieces between the straightening rollers, the energy stored in the tie rods or machine frame during the straightening process temporarily acts on a shorter section of the workpiece.

If workpieces such as bars or tubes are straightened in a straightening machine, the so-called skew rolling on v / iron, the workpiece is passed through

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3AD

Th. Kieserling £ Albrecht October 16, 1970 Golincen Fat.Abt.Koe / Huck / Bch

Latin registration file K 1 ^ 9

the straightening rollers are given a rotation about the longitudinal axis. As a result, the not yet directed end of the workpiece performs a striking movement, whereby both the workpiece, if it is a question of pipes, as well as the feed channel can be damaged. In any case, these entry channels are subject to aiB high wear.

In order to avoid this disadvantage, it has been proposed that the line gutter be made up of several pairs of hyperbolic rollers to form, which partially include the V / alzgut. liLne series of these roles can be against the other Row to be employed. For this purpose, a roller is arranged in each case in a carrier. All Carriers are shared around a parallel to the Verkstückachae running axis pivotable. The swing out or the rollers are pressed against the workpiece by a double-acting piston. The cheek pieces to be straightened are fed from above and can, when one of the rows of rollers is swung out, fall between the rollers. Then it will be the piston is so loaded that the pivotable row of rollers is brought to rest elastically against the workpiece · 1 "LLr the advance of the workpiece is dae The pair of rollers closest to the leveler are driven. It is also provided that the roles are arranged adjustable in their holders eo that the angle that the longitudinal axis of the rollers with the Form the longitudinal axis of the "piece", can be adjustable, so that a certain diameter range is dominated will.

209826/0079

3AD ORtQfNAL

Th. Kieeerling & Albrecht October 16, 1970 Solingen Tat.Abt.Koe / Huck / Bch Patent application file K 159

Due to this arrangement and design of the inlet channel, the lapping of the not yet directed .. erupting prevents v / grounding, a continuous Straightening, i.e. a continuous passage through the straightening rolls of the straightening rolls to be fed one after the other , Workpieces are not possible as a result. (DP 725 620)

Regarding the state of the art, it should be noted that it is known, for example, in peeling machines, that the workpieces | to be guided seamlessly through the circumferential cutter head. This can be done, for example, that the halls of the guide roller table rise one Have feed speed than that of the rotating one. Feed rollers in front of the cutter head · If the workpiece to be tracked the 'workpiece to be hauled in reached, there is a slip between the studs of the feed roller table and the "'erketück. But that is not critical, because the workpieces in the previously known ^ chalmadchinen during their length movement do not perform any turning movement.

According to the invention, to avoid said j

HachtiIe suggested the workpiece to be tracked temporarily accelerated on its trajectory for a seamless approach to the workpiece to be hauled in advance. It is preferably provided that the feed rate of the v / er piece to be traced Can be changed depending on the movement of the workpiece to be hauled in.

209826/0079

Th * Kieserling & Albrecht October 16, 1970 Solingen councilor Koe / Huck / Bch Patentarune! Dung file K 159

This accelerated approach of the future Workpiece to the workpiece already located between the straightening rollers can according to the invention can be solved in different ways. Preferably, this is achieved according to the invention in that the Angle which the longitudinal axes of the Hvperbolrolle »it the longitudinal axis of the workpiece, when Passing through the nachuführenden workpiece through the hollen can be changed. Preferably that will Pivoting the lobes achieved in that the holder of the rollers by double-acting piston drives in the horizontal I plane perpendicular to the longitudinal axis dee The workpiece arranged pins are pivotable, whereby the supply and discharge of the pressure medium for the Beauf the double-acting pistons are hit by an electromagnetically switchable reversing slide, which can be controlled by a ringing coil to be passed through by the workpiece, which has the inductance of a Oscillating circuit forms each front or * behind End of the workpiece entering the ring coil generates a switching pulse, which, as is known at eich, causes the reversing slide for the pressure medium the piston is switched accordingly. This switching pulse also causes the gradable The roller is moved away from the other roller or moved back towards it in order to clamp the workpiece B wiping the rollers. Likewise, the inlet channel, in which the pair of hyperbolic rollers between is switched, closed or opened by such a switching pulse to the next workpiece Let it fall into the gutter between the rollers

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Kieserling & Albrecht October 16, 1970 Solingen. Pat.Abt.Koe / Huck / Bch FatentanmeldunR File K 159

and to close the gutter as soon as the hells move the workpiece forward axially.

When straightening workpieces with a large diameter On such straightening machines, the straightening speed 80 can be low so that it is also possible to use the Hyperbolic scrolls at times with increased speed to drive without changing the angle of attack. ^

■ as a result, the "piece" gets a rotation of its own, ^

which is greater than the Ui turn, which the "Erk-8tück has that is already between the" alzen. When judging workpieces with small Diameter, for example up to 100 mm, would not satisfy this solution, because then the “York piece would be a The rotation of the kite is much higher than the rotation of the work piece located between the catfish " is.

Target of a 'workpieces · done merely by temporarily increasing the speed of Hyperbolrollen the accelerated tracking, so the invention, the rollers driven by hydraulic motors according to one OF PREFERRED λ th embodiment, where the ^ ruck oil electromagnetically switchable by a pump with adjustable delivery rate over a The drive of this oil pump is also derived from the drive of the straightening rollers, so that the hyperbole rollers give the workpiece a feed speed at normal speed that corresponds approximately to the conveying speed that is given to the workpiece when it passes through the straightening rollers. Influencing the

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Th Kieeerllng & Albrecht October 16, 1970 Solingen Pat.Abt.Koe / Huck / Bch patent application file K 159

Reversing spool and the pump with adjustable flow rate is also in this case by the Ring coil traversing front or rear end, as already mentioned above.

At iiand the drawing "uie in den x" ig. 1 to 7 two Exemplary embodiments for carrying out the method according to the application show, is its structure and, the manner of operation is explained in more detail below.

In Flg. 1 shows, according to an exemplary embodiment, the structure of a straightening unit in a top view, with the feed device with swiveling hyperbole rollers between the inlet channel and a downstream double channel is*

In Fig. 2, this feed device is in a view - in the direction of passage de Seen what is not good - reproduced, one of the two pivot pins for pivoting the feed rollers being shown in section.

FIG. 3 is an enlarged view of the hatred along the line A-B of FIG and puts the - ^ cone in the ^ outer- · cut in connection with a pan

209826/0079

Th. ILieserling <k Albrecht 3olingen

Patent and urn-making!;

October 16, 1970 I at. Dept.Koe / Huck / Bch File K 159

Cylinder and the associated, adjustable stroke limiter.

4 shows the feeding device in

a section along the line G-J of Fig. 2.

The Pig. 5 shows the hydraulic scheme of the feeding device after the first execution example.

In / ic. 6 is a schematic of the structure according to a further exemplary embodiment a straightening unit reproduced.

The Pig. 7 shows the inlet channel in a cross section.

The foldable infeed channel 1 is arranged laterally next to the feed grate 2, parallel to its longitudinal axis. Unmistakably behind the one facing the IUchtmaschine 3 ünde the inlet channel 1, the feed device 4 is arranged so that the material to be straightened after open the line gutter 1 and the in the open position brought .Solle 5 with its front end between the feed rollers 5 and 6 can fall / into the feeder 4 is followed by an intermediate channel 7 » the length of which is so dimensioned that the following material to be straightened ahead of the material to be straightened on the otrecke between the ring coil 8 upstream of the straightening machine 3 and the straightening rollers 9 and 10. The straightening machine 3 is followed by a further ring coil 11, which is followed by an intermediate channel 12,

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209826/0079

BATH

Th. Kieser1ing & Albrecht October 16, 1970 Solingen Iat.Abt.Koe / Huck / Bch

Patent application; File K 159

whose lungs are so dimensioned that that of the following Pull-out device 13 transported into the discharge channel 14 In this way, items to be straightened can be placed on the discharge grate 15 at an early stage at a high extraction speed can before the subsequent material to be straightened can reach the pull-out device 12.

The feed device shown for the first embodiment in Figures 2 to 5 takes on the side of the frame 16 facing the feed grate 2 in a vertical guide 17 the pivoting unit of the feed roller 6, which is mounted in a height-adjustable manner via a threaded spindle 1S. On the side facing away from the feed grate 2 , a bearing plate 19 is rotatably mounted in the bearing block 20 of the frame 16. The bearing plate 19 is connected to a cylinder 21 hinged to the frame 16 and can thus be folded down. In the vertical guide 22 of the agerschildee, the pivoting unit of the feed roller 5 is mounted so as to be vertically displaceable and can be adjusted by means of the threaded spindle 23. The pivot pin 25 is mounted in the two-part housing 24 and can be adjusted radially to the object to be straightened via a spring-loaded threaded spindle 26 and the handwheel 27 connected to a threaded sleeve 26a. A hub 28 is non-rotatably connected to the pivot pin 25 at the level of the parting line of the two-part housing 24. The socket 28b protrudes into a housing 30 which is connected to the housing and which contains stop pieces 32, 32a which can be adjusted via the threaded spindles 31, 31a,

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BAD ORfGiNAL

2U51Ü87

'Th. Eieserling &Albrecht; October 16, 1970, "Jolingen Fat.Abt.Koe / Huck / Bch rat entaniae! Dung _t file E 159

by means of which the stroke of the cylinder 29 and thus the ochv / enk area of the pin 25 are set can. The pivot pin 25 is fixed to the holder 33 of the feed roller 5 connected, the holder at the same time receiving the drive motor 34 and the Coupling 35 is used. The structure of the ^ chwenkaggre, ates the feed roller 6 corresponds analogously to the above-described structure of the tilting unit 3 for the feed roller 5 ·

The outflowing IIol-

On rod there is a switching cone 364 which controls the limit switch 37 actuated,

The functioning of the device described above is v / ie follows:

The light well is first placed on the feed grate 2 in such a way that it comes to rest with its face on the length stop 2a (I ¹ Uο 1) and with its outer surface on the adjustable Jeitrnanschllagen S3 (Pig. 7) except for the rotors 38 and 39 for driving the light rollers "

9 and 10 also the motor 40 switched on, which the luupe 41 drives (Pig. 5). The rag 41 sucks out of the Tank 42 applies the pressure medium via filter 43 and line 44 and presses it via the check valve 45 in the lines 46, 47, 48 and 49. Via dnc -iückschlagveritil 50 the pressure medium reaches the wi;>; netventil 51, which in the position shown the Line 47 connects to line 52. The pressure medium geljaigfc 3omib via the Dronsel-Hückschlagven-

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"bad original

2US1087

Kieserling & Albrecht October 16, 1970 ngen Pat.Ab

Patent application file K

Solingen Pat.Abt.Koe / Huck / Bch

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til 53 into the cylinder 21 and acts on the double-acting piston 54 in such a way that the swivel unit attached to the -kxgerschild 19 is folded into the position shown in FIG. If the V / Erkatück is not inserted, the bearing shield I9 folds against a stop (not shown). The displaced pressure medium flows back into the tank W via the throttle check valve 55t, the line 56 and the solenoid valve 5I Pressure medium can flow back into the drinking via lines 58 and 59.

The pressure medium conveyed into the line 48 arrives via the check valve 60 to the solenoid valve 61 _f which, in the position shown in FIG. 5, connects the line 48 with the line 62. The line 62 is connected to the lines 63 and 64, so that the pressure medium reaches the cylinder 29, 29a via the throttle check valves 65 and 6C W and the double-acting piston 67, 67a is applied so that the feed rollers 5 and 6 via the pivot pin 25, and I are pivoted to a position 28, wherein the included angle between the longitudinal axes ^5a and Ga ert of the feed rollers and the longitudinal axis of ßichtgutes 68 the largest predetermined by the stop 32a>. '(Pin · 4 and Pi £ > 3), which is necessary in order to be able to transport the tiicht-CUt with catching up speed. L) uü verdrängbe ^ ruckmibbül flows over the uroiujol- ^ u

2 fl 9 8:> G / I) 0 7 9

BATH

2Ü5108?

Th. Kieserling & Arbrecht October 16, 1970 üolingen ■ Iat.Abt.Koe / Huck / Bch

1 patent application file K 1 ^ 9

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impact valves 69, 70 and lines 71, 72 and 75 back into the tank via the solenoid valve 61 · .Venn die Lolbcn C7 »C7a the have 28 with their love seat 26b have pressed against the stops 52a, the overpressure that builds up after reaching the pressure relief valve 57 set pressure is reduced via this valve and the pressure medium flies over the Lines 5C and 59 and valve 57 into the tank return. "

Pressure oil pumped into the line 49 passes through the non-return valve 74 · to the pump 75 »which is flanged to the plant 76 of the -vichtv / alze 10 and is thus driven by the straightening roller as a function of the speed · the j. uape 75 conveys the pressure medium via the line 77 »the check valve 78 and the line 79 to the two in series. th motors 34- »34-a which drive the feed rollers 5 and 6. The pressure of the pressure medium is set by the pressure limiting valve 80. The motor ZA- wifd bridged by the line 85, in which a throttle 86 is installed, which ensures that the speeds of the two motors 34-, 34a are the same. The pressure medium is sucked in via the line 81, the check valve 82 and the line 84 by the pump 75 and fed back to the L-Iotoren 3 ^ i 34a, or eo flici: t, if the pressure is above the set level in in line 84 rises, back into the tank via pressure relief valve 83

Shortly after switching on the straightening system, the hinged end shield 19 with the feed roller 5 in

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BATH

¹ Th * Xieaerling & Altrecht October 16, 1970, Solingen. Pat.Abt.Koe / Huck / Bch

Patent application file K 159

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"Z-Gtstellung" folded, the feed rollers 5 and 6 are pivoted to the large angles required to achieve the catching-up speed and rotate at a corresponding speed derived from the gear unit 76 of the straightening roller 10. The device is thus prepared for the straightening process and this is initiated by a known sequential circuit. As a result, the first V / piece lying on the side stops 93 is lifted into the lifters 95, which are actuated by a piston guided in the cylinder 94, and is placed above the inlet channel 1 An impulse is given to switch on a time relay, after which the inlet channel 1 is opened by a corresponding actuation of the Eolbene guided in the cylinder 96 and the solenoid valve 51 is reversed, whereby the pressure medium via the line 47, the solenoid valve 51, the line 56 and the throttle ! -Check valve 55 acts on the piston 54 of the cylinder 2Λ in such a way that the bearing plate 19 with the feed roller 5 is folded into the "open position" closed again and since the solenoid valve 51 is reversed again, wq through the piston 54 of the cylinder 21 the bearing plate 19 al t of the feed roller 5 back into the "closed position ^H" against which the workpiece 68 has meanwhile fallen into the inlet channel 1 and between the feed rollers 5 and 6. At the moment when the piston 54 presses the feed roller 5 against the date 7 / piece 68, the lower end releases

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BATHROOM OPUQtUAL

2061087

Th. Kieserline 3k Albrecht October 16, 1970 »Jolingen I at .Abt .Eoe / IIuck / Bch

i atentaniae! dung file K 159 ,

- 135 -

attached to the piston rod of cylinder 21; Jchaltkegel 36 via the: jnd switch 37 the liapuls zui.i lift off of a second ..erk.ntiickes 68a from the feed grate 2

over and deflecting this workpiece / the inlet channel 1 from. Simultaneously wira jeira pressing the feed roller 5 against the .. piece as a result of the feed rollers 5 and 6 rotating in the <-> chrÜ3lage turning your jerk ^ piece a helical Be we gun .., granted, ie the .. piece receives a! It is moved forward onto the light rollers 9 and 10 in the clearing. Since the longitudinal "axes of the feed rollers 5 and 6 are at a relatively large angle to the longitudinal axis of the Uichtgutes 68, the intrinsic speed of the food is low and the gate speed high. solves this a pulse for actuating the Uagnetventils 61 in. thereby v / 48 ird the line with the line 73 connected _t whereby the pressure medium via the lines 71 ♦ 72 and the Drosoel-Rücknchlagventile 69, 70 flying in the cylinder 29, 29a. JJann the pistons 67, 67a are acted upon in such a way that the pivot pins 25 are rotated until the lever lugs 28b rest against the stops 32. The holders 33 of the feed rollers 5 and 6, which are firmly connected to the .Jchv / enkapfen, are pivoted so that the 11 ' The longitudinal axes of the feed rollers 5 and 6 enclose a smaller angle with the longitudinal axis of the light material 68; this angle corresponds to the resulting V / angle that results from the angle that the longitudinal axis of the ob The light roller 10 forms with the longitudinal axis of the light material and the angle that the longitudinal axis of the lower light roller 9 forms with the longitudinal axis of the light material.

2 0 9 B: ti / ή f) 7 fi

Th. Kieserling ί

Solingen

Patent application

Albrecht

October 16, 1970 Tat.Abt.Koe / Huck / Bch File K 1 ^ 9

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The diameter and speeds of the feed rollers 5 and 6 are selected so that the peripheral speed of the feed rollers corresponds to the peripheral speed of the straightening rollers. Thus, the feed rate and the spin rate adjust themselves on straightened 68, which are the objects to be straightened issued by the ⁿ .ichtwalzen 9 and 10. FIG. The Richtgiii. now runs in between the light rollers and the Richtvoxgc-.g begins. When the process has progressed so far that the axis of the workpiece located between the straightening rollers leaves the feed rollers 5 and 6, the piston guided in the cylinder 21 pushes the feed roller 5 briefly in the direction of the feed roller 6 and thereby releases its ochaltkegel 36 the iJndschalter? 7 free of open a pulse to the run-in gutter 'and outputs for the actuation of two solenoid valves 51 and 61, whereby the supply roller 5 in weggeklaprt already described above ..eise on the piston guided in the cylinder 21. In addition, the feed rollers 5 and 6 are pivoted by the pistons 67, 67a guided in the cylinders 29-29a until the angle between the longitudinal axes 5 & 6a of the feed rollers and the longitudinal axis of the light material is again so large that the workpiece to be tracked is moved forward at. At the same time, a further pulse is given by the switch 37 to switch on a relay, after which the inlet channel 1 is closed again and the solenoid valve 51 is switched over again, whereby the feed roller 5 is returned to the cylinder via the piston 54 guided in the cylinder "To-.jtellunc" is driven.

2 0 9 0 2 G / 0 Ü 7 Π

^BATH

2Öb1ü87

Th. Kiecerling & Albrecht October 16, 1970 Golingen Pat.Abt.Koe / Huck / Bch 1 registration file K 159

During the expiry of the last-mentioned time relay, the second .. piece 68a, which was already above the inlet channel 1, fell into the open inlet channel and between the two feed rollers 5 and 6. Glue the Liniauf channel and the feed rollers are closed by the switching cone 26, the limit switch 37 is actuated again, which then generates the impulse to lift the third V / Erkutücks from the feed grate 2 and place it over the. , gutter 1 gives »|

I;:. '. Ch JchlieJDen the feed roller ...;', 6 the ./erkstück 68a to be tracked is also accelerated to the leading ..cracket 68 located between the straightening rollers 9 and 10. When the rear jade of the workpiece 68 running ahead reaches the coil 8, the coil 8 triggers an impulse to actuate an input control, which monitors this component from the coil δ up to the middle of the non-volatile zones 9 and 10. Shortly after the .erkstück 68, the coil 8 has left, the front ', Jide reaches the subsequent "V'erkütückes 68a which jpule C, v / odurch an adjustable time relay, etc.

is switched on, after which the solenoid valve 61 is switched over. This causes the pistons 67, 67a acted upon so that the feed rollers 5, 6 are swiveled to the smaller angle at the moment, when the front iind of the workpiece 6Ca the rear -iJnd of the ..erkstücks 68 on the otrecke «..Mixing the coil 3 and the straightening rollers 9 and 10 has caught up. 3 As soon as the one preselected on the vegetal control device ^ when it has expired, the V / egcontrolled an impulse through which the in the frame

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'bad original

Th. Kieeerling & Albreoht October 16, 1970 Solingen patient department Koe / Buek / Boli

latent application file K 159

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13a pull-out fulls 13 arranged so that they can move in opposite directions against the calibration between inside Workpiece 66 are pressed so that the workpiece can be fed to the discharge channel 14 in an accelerated manner can. .When the rear Jew of this piece is the When coil 11 is reached, this triggers a pulse to switch on a timing relay for so long runs until the workpiece lies in the discharge channel 14. After the selected time has elapsed the following functions are triggered by the timing relay! Open the pull-out rollers, stop the pull-out rollers and Open outlet channel 14-. Dae switches at the same time Heiais on its expiration another "time relay, which after falling out of the work pieces au * the discharge channel 14 has run down on the discharge grate 15 and then gives a switching pulse, whereby the discharge channel is closed again · In the meantime, the following workpiece is between the Straightening rolls 9 and 10 run and leaves with seiaea rear end the feed chutes 5 and 6 *

The puncture procedure described above can repeat themselves with a sequential circuit *

In the second embodiment according to FIG. 6, the higher advance stroke speed required to catch up between the aichtwalsen 9 and 10 is not due to swiveling · » the feed rollers 5 and 6, but by increasing the speed of the oil motors 54, 34a and thus the feed rollers. 5 and 6 reached. The feed rollers 5 and 6

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Th. Eieserling & Albrecht October 16, 1970 Solingen Pat. Abbot * Koe / Huck / Bch

Patent application for file K 159

- 17 -

are therefore not pivoted · The speed change of the oil motors 34 »54-a is achieved, by a pivotable axial piston pump 87 via an adjustment mechanism consisting of a threaded spindle 88, a drive stage 89 and a Servomotor 90 is swiveled · With increasing swivel angle the two are also connected in series oil motors 91 »91a more pressurized oil supplied · The Servomotor 90 v.lrd over the ring coil 8 and a through the piston rod of the lock cylinder of the Feed roller 5 operated limit switch operated (as in the first embodiment) »their pulses on Time relays combined in a switch cabinet 92 and amplifier are passed on, which the running time of the Litellmotore 90 and thus the respective Determine the pivot angle of the axial piston pump 87 *

The manner of puncture is the same as that described above for the first exemplary embodiment with the The exception is that the change in the feed speed of the product is caused by a change in the speed of rotation I. the infeed rollers 5 and 6 are made

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209826/0079

Claims (1)

Th. Kieeerling & Albrecht October 16, 1970 Solingen Fat.Abt.Koe / Huck / Bch Patentanac! Dung file £ 1 $ ^ - 18 - patent claims 1 · Procedure for feeding round «calibrated during machining in particular straightening machines, by means of driven hyperbole rollers which can be set against one another and whose angle of inclination is adjustable, characterized in that, that the workpiece (68a) to be tracked is brought up to the workpiece (68) to be hauled in without any gaps on its movement platform is temporarily accelerated 2 · Method according to claim 1, characterized in that the feed rate of the workpiece (68a) to be adjusted in Depending on the movement of the workpiece (68) to be hauled in. Can be changed. 3 · Device for carrying out the procedure according to claims 1 and 2, characterized in that the .Vinkel that the Longitudinal axes (5a, 6a) of the% perbol rolls (5, 6) with the longitudinal axis of the workpiece Include (68), while the workpiece (68) passes through the rollers, can be changed. - 19 - 209826/0079 ORIGINAL* (Th. Kieserling Sk Albrecht October 16, 1970 Solingen Fat.Abt.Koe / Huck / Bch patent application file K 159 - 19 - 4. Vorrichtunc according to claim 31, characterized in that that the holder (33) of the lobes (51 6) by double-acting pistons drive (29) around in the horizontal plane vertically to the longitudinal axis of the Yerkut (6G) arranged pegs (25) "are pivotable, wherein the supply and discharge that pressure medium for acting on the double-acting pistons (67, 67a) via a electromagnetically switchable reversing spool (61) takes place, which is carried out by a toroidal coil through which the V / trkstück (68) is to pass is controllable, which forms the inductance of a resonant circuit. 5 · Device for performing the method according to claims 1 and 2, thereby characterized in that the rollers (5t 6) are driven by oil motors (91 »91») aind, to which the pressure oil is fed by a pump (87) with an adjustable delivery rate, the jjitrieb the oil pump is derived from the drive (76) of the straightening roller (1O). 209826/0079