EP0006074B1 - Device and method for calibrating and straightening tubes by means of a calibrating unit provided with calibrating jaws - Google Patents

Description

The present invention relates to a device for calibrating and for straightening pipe sections with the aid of a calibration unit provided with calibration blocks, to which on one side a feed device and on the other side a discharge device for the pipe pieces are connected coaxially to one another, both feed device and the discharge device is also equipped with driven conveyor rollers and a method for operating the device.

Calibration devices are already known which have a central calibration unit and a feed and also a discharge device which are connected to the calibration unit on both sides of the same, with the same axis. The feed and discharge device has driven conveyor rollers. With the help of the conveyor rollers, the mostly 8-10 m long pieces of pipe are fed to the calibration unit, where they are calibrated in sections by closing or opening the calibration jaws.

Since the pipe sections do not run straight, but are spatially curved from the production, it would be desirable if the pipe could not only be brought to the nominal size, but also straightened, so that ultimately the entire pipe has the prescribed diameter and no significant curvature having. Deviations from the nominal dimension in diameter and from the straight course must be tolerated small, because at the high pressures that usually prevail in the pipe, e.g. if this is used as a pipeline pipe, deviation from the round shape or from the prescribed course leads to overstressing, which can cause pipe breaks with unforeseeable consequences.

When operating the otherwise very reliable and practical calibration machines of the type mentioned at the outset, however, a major disadvantage arises that straightening the tube is no longer possible. Because during straightening, the pipe loses the target dimension to which it was previously calibrated. When the jaws are closed or opened, they suddenly act on the comprehensive pipe section, as a result of which both the pipe and the calibration machine are overstressed in terms of bending stress and surface pressure and are consequently often damaged.

The purpose of the present invention is to propose a device which allows a precise calibration and straightening of the pipe section without the pipe or the calibration machine being damaged as a result of overexertion by frictional and mass acceleration forces.

The device is characterized in that the vertically adjustable and lockable conveyor rollers are under the influence of hydraulic or pneumatic adjustment units, which are used to lock the height of the conveyor rollers with the help of sensors that are operatively connected to the calibration jaws for opening and closing the same stand, are controllable, and that to control the movement of the calibration jaws there is a drive unit which comprises an electric motor and a hydraulic unit which can be rubbed in several phases, the closing movement in the first phase with a large approach speed and in at least one of the succession, the phases take place at a considerably reduced speed, the hydraulic unit being controlled by the sensors attached to the calibration jaws.

The conveyor rollers are expediently mounted on rockers in the vertical plane and can be moved horizontally.

A method for calibrating and straightening pipe pieces is also described. Suggest with the help of such a device, in which the jaw closing process takes place in several stages, by moving the same. stopped when touching the tube to be straightened axially and in the subsequent straightening phase up to the beginning of the radial straightening to increase ovality with a significantly reduced. rth speed is continued.

• Fig. 1 eine Darstellung eines Richt- und Kalibriervorganges an Hand eines Diagrammes,
• Fig. 2-7 die prinzipielle Anordnung einer Kalibrier- und Richtvorrichtung,
• Fig. 8 eine Seitenansicht einer detailliert gezeichneten Vorrichtung, und
• Fig. 9 eine Draufsicht auf die gleiche Vorrichtung.

The basic arrangement and an exemplary embodiment of the subject matter of the invention are shown on the accompanying drawings

• 1 is an illustration of a straightening and calibration process using a diagram,
• 2-7 the basic arrangement of a calibration and straightening device,
• Fig. 8 is a side view of a detailed device, and
• Fig. 9 is a plan view of the same device.

1 shows a path diagram of the straightening and calibrating process, in which the pipe to be straightened and calibrated rests on rollers that are height-adjustable and lockable by braking, and is conveyed in batches to the straightening and calibrating jaws. The curve shows that in a first approach phase A, the closing movement of the jaws up to point B, where the tube is touched by sensors, takes place quickly. The height of the rollers remains unchanged when the brakes are closed. The straightening is then carried out in the straightening phase C at a significantly slower speed and in the next phase D the ovality of the pipe is remedied at an increased speed, while the actual calibration to reduce the pipe diameter is slowed down in the phase E. In phases C, D and E, the brakes are released so that the height of the support rollers can be changed, as will be described later.

As can be seen from FIGS. 2-7, the device for internal or external calibration and for straightening workpieces has a central calibration unit 1, which has calibration jaws 3 arranged in a beam around the central axis 2, of which in FIG. 2 -7 only two opposite are shown purely schematically. Each calibration jaw is equipped with two sensors 4. The calibration jaws 3 can be moved together in the direction of an opening or closing movement in the radial direction, so that the diameter of a tube inserted in the feed direction is reduced during the closing movement of the jaws 3 by pressing the jaws 3 together, or a tube that is not completely round is directed accordingly becomes. The common drive of the jaws 3 is not shown in Figs. 2-7.

In order to receive and convey the pipe 5 to be calibrated and straightened, height-adjustable supporting and conveying rollers 6 are provided, each of which is supported by a double cylinder 7. The double cylinders 7 are arranged vertically and each provided with a piston 8 and 9, which are equipped with a piston rod 10 or 11 extending upwards or downwards. The downwardly extending piston rods 11 connected to the pistons 9 are supported at the other end on a base plate 12, while each oppositely directed piston rod 10 of the pistons 8 carries a carrying and conveying roller 6.

Furthermore, a support roller 16 is arranged directly in front of the calibration unit 1, which is supported by means of a single-acting cylinder 13 and piston 14 with the aid of the piston rod 15. The cylinder 13 is supported on the base plate 12 by means of a fixed rod 17.

2 shows the position of the support and conveyor rollers 6 before they are loaded with a tube. First, the height of the base plate 12 is adjusted according to the tube diameter, so that the support rollers 6 and the support roller 16 are directed to receive the tube. The load that can be borne by each of the rollers 6 corresponds to the load to be carried. If the total weight of the pipe is designated G, a partial load of 1 G will fall on each roll, which corresponds to the weight of a pipe section between two rolls 6. The pressure in the upper cylinders 7a is limited to a load of LIG + 10%, while the lower cylinders 7b are first kept depressurized. In the unloaded position, the pistons 9 in each of the unpressurized cylinders 7b will hit the partition 18, while the upper pistons 8, due to the pressure d G + 10% prevailing in the upper cylinders 7a, assume the top dead center position (see FIG. 2 ). Now the rollers 6 are loaded with the pipe 5 to be calibrated and straightened and at the same time the lower cylinders 7b are pressurized with zl G + 10%. Since the tube 5 is curved, the weight distribution on the rollers 6 becomes uneven. The rollers 6 adjust themselves according to the curvature of the tube 5. The tube 5 is advanced by the driven rollers 6 so that its end reaches between the open calibration jaws 3 (FIG. 4).

The calibration jaws 3 are then moved together, initially at high speed, until two opposite sensors 4 touch the tube 5. Touching the sensors 4 causes the radial closing movement of the calibration jaws 3 to be stopped immediately. Immediately afterwards, the closing movement of the calibration jaws 3 is resumed, but with a much slower movement, until the position shown in FIGS. 6 and 7 is reached.

Dabei ist I = Rohrlänge

• e = Abstand der Rohrmittelachse von der Tragwelle 6 (Fig. 6)
• G = Gewicht des Rohres
• t = Richtzeit während das Rohrende den Abstand e durchläuft
• g = Erdbeschleunigung.

In this position, ie when the sensors 4 touch the end of the tube 6, a bending moment acts on the clamped tube during the closing movement

I = pipe length

• e = distance of the pipe center axis from the support shaft 6 (FIG. 6)
• G = weight of the pipe
• t = standard time while the pipe end runs through the distance e
• g = gravitational acceleration.

It can be seen from the above formula that if the closing movement slows down with increasing time, the moment is significantly reduced. Before the calibration jaws open again, all valves of the double cylinders 7 are closed, so that the tube 5 remains in the position it has assumed.

With the help of the support and conveyor rollers 6, the tube 5 is conveyed in the conveying direction by the same amount as the length of the calibration jaws 3 and the jaws 3 are then closed again in two stages, as described. The valves of the double cylinders remain closed until the tube 5 touches the sensors 4. With the touch, the valves of the double cylinder 7 are opened and the closing movement of the calibration jaws continues to be significantly slowed down.

In this way, the stress on the pipe to be calibrated and straightened is greatly reduced. At the same time, the calibration system is protected. After the description of the principle, a practical embodiment of a system is then explained in more detail with reference to FIGS. 8 and 9.

According to these figures, there is a central calibration unit 21, which has calibration jaws 23 arranged in a beam around a central axis in a frame 22, which can be displaced together in the radial direction in the sense of an opening or closing movement, so that the diameter of a tube introduced in the direction of arrow P during the closing movement of the jaws 23 by pressing them together is reduced or a not completely round pipe is directed accordingly. The common drive of the jaws 23 for radiating merging or driving apart is not shown in the drawing and may be assumed to be essentially known. An electric motor 24 and a hydraulic unit 25, which controls the movement of the jaws 23, are provided for the drive. The drive unit 24 and 25 thus formed is designed such that the normal closing movement of the jaws, which takes place at a high speed, is replaced by a closing movement, which is carried out at a throttled speed, after an intermediate stop in a second phase. Accordingly, the fully open jaws 23 are first brought together at high speed and brought to a standstill when the tube is touched by the sensor 26. The changeover to the second phase is also carried out by these sensors 26, which are arranged offset in the axial direction with respect to the central axis 27 on diametrically opposite jaws. If the sensors 26 touch the pipe section (not shown) that is introduced, to be straightened and calibrated, they interrupt the closing movement of the jaws and convert the hydraulic unit 25 so that the jaws 23 are pressed together again at low speed. During the actual straightening and calibration of the pipe section to the prescribed target dimension, the closing speed of the jaws was considerably reduced. Another function of the sensors 26 is to control brakes, as will be described in detail later.

8 and 9, the central calibration device 21 is preceded by a feed device 28 on the left side and a discharge device 46 on the right side. The feed device 28 consists of a floor structure 29, which is designed to accommodate the entire pipe piece to be processed and a considerable length, for. B. 9-10 m. For receiving, supporting and conveying the pipe section, conveyor rollers 30 are provided, which are each arranged on a support axis 31 running perpendicular to the conveying direction and are driven together. The conveyor rollers 30 are axially displaceably mounted on the support axles 31 and are connected to one another with the aid of a loose centering rope 33 such that when the centering rope is tightened, each roller 30 assumes the central position on the axle 31. With the loose rope 33, however, the rollers 30 can be freely moved on their axes 31.

Each axis 31 is supported on both ends in an arm 34, which arms 34 are each pivotably mounted in a vertical support 35. The pivot point is designated 36. Furthermore, two arms 34 arranged on the same axis 31 are connected to one another by a V-shaped double arm 37, so that a pivotable rocker 38 is formed by the parts 34 and 37. The associated rollers 30 are pivoted in the vertical plane by the rocker movement.

Each rocker 38 is influenced by a pneumatic unit and a brake 44, the latter of which can lock the rocker movement. The pneumatic unit has a first air cylinder 39 with a piston and piston rod 40 and a second cylinder 41, also with a piston and piston rod 42, the latter of which is pivotally attached to the floor structure 29 with its free end. The two cylinders 39 and 41 are arranged in a common housing, from which the piston rod 40 of the first cylinder 39 extends in the opposite direction to the piston rod 42 of the second cylinder 41 and is connected to the V-shaped tip of the double arm 37. The first cylinder 39 is dimensioned such that the extended piston rod is able to carry the pipe weight and, in addition, 10% of the pipe weight, while the second cylinder 41 has a somewhat smaller load capacity, which is approximately 10% less than the pipe weight. In the position shown in FIG. 8, the piston in the first cylinder 39 is pressurized with air and the piston rod 40 is extended, while the second cylinder 41 is without air. The corresponding pressure for the cylinders must be adapted to the respective pipe weight. The height adjustment of the rollers for the different pipe diameters is done by a motorized adjustment unit.

Furthermore, each rocker 38 is provided with a brake 44 which can lock the rocker in any position. In the area of the conveyor rollers 30, light barriers 45 are provided which control the air supply to the pneumatic units. The actuation of the brakes 44 is coupled to the feed device and to the sensors 26, in such a way that the brakes are applied before the onset of the feed and the brakes are released when the sensors 26 are actuated. Furthermore, there is a secondary connection of the brakes with the fastening of the jaws 23 in the sense that the brakes are used to lock the rockers during the opening of the jaws 23.

The discharge device, which extends on the other side of the central calibration device 21 coaxially with the feed device 28, has vertically movable conveyor rollers 48 in rockers 47, by means of which the calibrated and directed pipe pieces are removed.

The tube 49 to be machined, which is mostly made of sheet-metal material, must be calibrated and straightened, since it is irregular both in diameter and in the longitudinal course after manufacture. The tube 49 is first parallel to the feed device 28 and is placed from the side onto the conveyor rollers 30, which are previously brought into the starting position corresponding to the calibration axis, the light barriers 45 being interrupted. The interruption of the light barriers 45 has the effect that the other cylinder 41 also receives air.

The tube is then moved by the driven conveyor rollers 30 in the direction of the central calibration device 21. When the feed begins, the brakes 44 are actuated, as a result of which the rockers 38 are held in their current position. The conveyor rollers 30 can therefore no longer be moved vertically, but are horizontally displaceable on their supporting axes 31.

The first feed period ends when the pipe section comprising the pipe end is in the open calibration jaws 23. For straightening and calibrating, the drive of the calibration jaws 23 is activated, whereupon they initially move into the closed position at high speed. As soon as the sensors 26 of the calibration jaws 23 come into contact with the tube section lying in between, the closing movement of the calibration jaws 23 is interrupted. At the same time, the brakes 44, which block the rockers 38, are released. The closing movement of the calibration jaws 23 is then continued in a second phase at a considerably reduced speed, so that the pipe section is first straightened and then calibrated. When the target diameter is reached, the proximity jaws 23 are opened by a proximity switch, in that this proximity switch influences the drive of the jaws 23 accordingly. This proximity switch previously has the effect that the brakes 44 are applied again and the rockers 38 are thus blocked. The conveyor rollers 30 can therefore no longer move vertically, but only move horizontally on the associated support axes 31. The feed is then started again and a further section of the pipe is fed to the central calibration device, etc. Since the actual straightening of the pipe section and the subsequent calibration does not start suddenly at high speed, but takes place at a significantly reduced speed of the jaws, occur during the Do not set up any impermissible bending stresses and surface pressures. Furthermore, the free end of the tube will move smoothly by simultaneously moving the conveyor rollers 30 on the support axles 31. The fully calibrated and directed pipe is fed to the rollers 48 of the discharge device 46.

When the straightened and calibrated tube is removed, it comes to rest on the rollers 48, which are pivoted in succession from a lower rest position into a higher carrying and conveying position as the feed progresses. This movement can again be controlled by appropriate light barriers and triggered by pneumatic means.

Before feeding a new pipe, the conveyor rollers 30 are brought into the central position by tensioning the centering rope 33. As soon as the new pipe lies on the rollers 30, the rope 33 is loosened so that the conveyor rollers 30 can adjust laterally in the horizontal plane. The pipe section is then straightened and calibrated as described.

Finally, it should be mentioned that the pneumatic means can also be replaced by hydraulic means.

Claims (10)

1. Apparatus for calibration and alignment of pipe sections (5, 49) by means of a calibrating unit (1, 21) equipped with calibrating jaws (3, 23), said calibrating unit being equipped, on the one side, with a feed mechanism (28) and on the other side with a discharge mechanism (46) for the pipe sections (5, 49), coaxially arranged to each other, whereby both the feed mechanism (28) as well as the discharge mechanism (40) are equipped with driven feed rolls (30, 48), characterized in that the feed rolls (6, 30, 48) disposed adjustably and fixably in their vertical height, are under the influence of hydraulic or pneumatic shifting units, which are controlled with the help of sensors (4, 26) for fixing the height position of the feed rolls (6, 30, 48), the sensors being operatively connected with the calibrating jaws for opening and closing said calibrating jaws, and that for controlling the movement of the calibrating jaws, there is provided a driving unit, which comprises an electric motor and a hydraulic unit, which is operable in several phases, whereby the closing movement in the first phase is effected with a high approach speed and in at least one of the successive phases with a substantionally reduced speed, the hydraulic unit being controlled by the sensors (4, 26) attached to the calibrating jaws (3, 23).

2. Apparatus according to claim 1, characterized in that the feed rolls (6, 30, 48) are mounted on tilting tables (38, 47) and are swiveably arranged in a vertical plane and shiftably arranged in a horizontal direction.

3. Apparatus according to claim 2, characterized in that brakes (44) are provided for stopping the movement of the tilting tables (38, 47), said brakes being operatively connected to said sensors (4, 26).

4. Apparatus according to claim 3, characterized in that the pneumatic or hydraulic unit comprises a first cylinder (39) with piston and piston rod (40) as well as a second cylinder (41) with piston and piston rod (42), which are attached swiveably at their free ends.

5. Apparatus according to claim 4, characterized in that the cylinders (39, 41) are counteract- ingly disposed in a common housing and are dimensioned such that the one cylinder (39) carries a little more and the other cylinder (41) carries a little less than the pipe weight.

6. Apparatus according to claim 5, characterized in that light barriers (45) are provided in the area of the feed rolls (30), which control the feed of the pressure medium to the pneumatic or hydraulic units (25).

7. Apparatus according to claim 6, characterized in that the light barriers (45) are in operative connection with the feeding means for the feeding of the weaker cylinder (41) with pressure medium.

8. Process for calibration and alignment of pipe sections (5, 49) with an apparatus according to claims 1 and 2, characterized in that the closing process of the jaws (3, 23) takes place in several steps, whereby the movement of the jaws is stopped as soon as the jaws contact the pipe section (5, 49) to be aligned axially, and whereby in a consecutive alignment phase, said movement of the jaws is continued with a substantially reduced speed up to the beginning of the radial alignment phase to eliminate the oval shape of the pipe section.

9. Process according to claim 8, characterized in that a radial alignment of the pipe for eliminating the oval shape takes place at an increased speed of the jaws, after the slow axial aligning phase of said pipe, whereby the speed is again substantially reduced in case of the real calibrating process for the decrease of the pipe diameter.

10. Process according to claims 8 and 9, characterized in that during succesive feeding of the pipe sections (5, 49) into the calibrating unit (1, 21), the vertical movement of the tilting tables (38, 47) is blocked until the calibrating jaws (3, 23) touch the pipe sections to be calibrated during their closing movement, and after the jaws having contacted the pipe section, the blocking of movement of the tilting tables is cancelled and after completed closing movement - before the calibrating jaws (3, 23) are opened again - the tilting movement of the rolls (6, 30, 48) ist blocked again.

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