EP1316371B1 - Welding device for tubes - Google Patents

Abstract

Tube welding device comprises a side closing structure (3) consisting of a base frame (6), a stand (7) on which a roller (4) rotates, and a bearing block (9) on which a roller (5) is rotates. The stand is arranged on the base frame so that its can slide across the longitudinal axis (8) of the tube. The bearing block is arranged on the stand so that it can likewise slide across the longitudinal axis of the tube. <??>Preferred Features: The base frame is arranged on a guide so that is can slide across the longitudinal axis of the tube. The axes (10, 11) of the rollers are vertically arranged. Sliding of the stand and the bearing block occurs horizontally or vertically to the longitudinal axis of the tube.

Description

The invention relates to a pipe welding apparatus according to the features of the preamble of claim 1, with which a tube formed from a flat metal strip is welded to the resulting seam, which has a side closing stand comprising at least two rolls, each partially forming the metal strip formed to the pipe and in that the side closure framework comprises: a base frame, a stator on which a roller is rotatably mounted, the stator being slidably mounted on the base frame transversely to the longitudinal axis of the tube, and a bearing block on which a roller is rotatably mounted the bearing block on the stand is also arranged displaceably transversely to the longitudinal axis of the tube. Such a pipe welding device is characterized by JP 60231526 A known.

In the production of metal pipes (especially steels and low and high alloy steels) a distinction is made between seamless and welded pipes. Welded tubes with diameters of up to approx. 600 mm are preferably manufactured continuously from an endless strip. For this purpose, the tape is divided to the required width, wound into coils and fed to a tube welding machine. In order to avoid interruptions in production, the tape joints of the individual coils are welded together during operation and using so-called tape storage.

The flat strip is formed after entering the pipe welding system, first by means of form scaffolds or by Linealformstrecken stepwise or continuously to form a round slotted tube. The molded tube then passes through a welding unit in which the strip edges are heated at the seam to welding temperature and welded together by compression. In a subsequent operation, beads and ridges of the weld are removed inside the tube and externally.

After passing through a cooling section, the tube is then rolled in one or more stands (caliber stands) to an exact diameter. In a final operation, the pipe is then divided by a follower separator in individual lengths. The individual tubes are collected and fed to their further destination.

Welded pipes are used for a wide variety of purposes. One part is further processed, for example, to water pipes. For this purpose, the pipes are hot-dip galvanized inside and outside. There are no high demands on the diameter tolerances on these pipes. It is not even necessary here to remove the inner ridge.

From other tubes, however, so-called precision tubes are manufactured, which must have particularly accurate diameter tolerances. These pipes are usually produced after welding by subsequent drawing on a drawing bench, since pipes with known pipe welding systems can not be manufactured with narrow diameter tolerances. By pulling additional manufacturing costs occur because the pipes must be pickled, rinsed, greased and fishing before pulling. After pulling, the hinges must be removed, which means increased material loss. Furthermore, the pipes must be degreased.

The subsequent subsequent welding to the welding therefore causes considerable additional costs, which makes the production process of precision tubes more expensive. In order to save these operations and the associated additional costs, one endeavors Produce precision tubes with high surface quality and tight diameter tolerances directly in the tube welding line. This requires several measures. For example, cold-rolled, bright strips must be used, which no longer descaled and need to be pickled. Furthermore, it is endeavored to make the rollers in the side frame for guiding (the so-called. Side closer) of the slot tube so that they are always set exactly to the center of the tube to harmful deflections from the ideal line of the tube, which is particularly harmful to the compliance of tight diameter tolerances are to prevent.

From the DE-OS 19 23 241 an apparatus for continuous longitudinal seam welding of pipes is known. The arrangement disclosed therein has a side frame, are mounted on the two rollers. Each roll comprises the tube-shaped metal strip over a peripheral portion of almost 180 °. The device known from this document has a unit with which a central control of the longitudinal seam in the area of the welding beam can take place. However, there are no measures provided in this solution to guide the pipe itself as accurately as possible in the system. Thus, there are limits here as far as the production of tubes with a tightly tolerated diameter is concerned.

The DE 32 12 365 C2 shows an arrangement of three rollers, with which the tube formed from the metal strip is guided almost over the entire circumference. The lower two rollers are inclined here, the upper roller is formed divided. The resulting from the upper roller two rolling discs can be pivoted to each other by an adjustable angle. Thus, the width of the center groove between the two discs of the upper roller can be adjusted continuously in dependence on the wall thickness of the molded tube. However, this also high demands on the diameter tolerance of the welded pipe can not be met.

Even with one from the DE-AS 12 89 814 known pipe welding apparatus, the side frame on two horizontally arranged side rollers. For the horizontal, lateral lateral relative movement of these rollers in the direction of the axis of the tube to and from this, devices are provided which sit on the housing below the corresponding rollers. However, these devices are not further disclosed.

When using all these known welding devices can not be dispensed with the downstream pulling in the production of pipes with narrow diameter tolerances. The production of such pipes is correspondingly expensive.

The invention is therefore based on the object, a pipe welding device of the type mentioned so that it is possible to produce pipes with narrow diameter tolerances and so to dispense with a downstream drawing process. This should reduce the cost of producing such pipes.

This object is achieved in that means are arranged between the base frame, stand and bracket, which allow a simultaneous and opposite movement of the stand or bracket relative to the base frame.

With this embodiment, it is possible in an advantageous manner to ensure a precise alignment of the tube formed metal strip in the side closer framework, so that the tube is always performed exactly in the ideal center plane. In every phase of the setting of the rollers of the side closer framework, the tube is thus always guided in a straight line. This allows the production of a pipe with a narrow diameter tolerance, without necessarily requiring a downstream drawing process. The manufacturing process for precision tubes is thereby considerably simplified and correspondingly less expensive.

For simultaneous and opposite displacement is preferably a threaded spindle. This has, according to a development, a first portion which is rotatably and axially fixedly mounted in the base frame. Furthermore, it may have a second portion which is provided with a first thread which communicates with a fixedly arranged in the stator threaded nut. Furthermore, a third section of the threaded spindle can be provided, which has a second thread, which is in communication with a fixed nut in the bearing block. One of the threads preferably has a right-hand thread and the other has a left-hand thread; If preferably the pitches of both threads are the same size, it can be ensured that the means, in particular the threaded spindle, the roller arranged on the stand and the roller arranged on the bearing block are always adjusted symmetrically. The two rollers of the side closer can thus be opened and closed by a single spindle, always maintaining an equal distance from the tube longitudinal axis.

A compact design is achieved when the stand has a U-shaped configuration. In this case, one of the rollers can be arranged in the region of a first U-leg; The bearing block can be supported in the area of the other U-leg.

Between the base frame and stand and between the stand and bearing block low-clearance, preferably backlash-free, linear guides are advantageously arranged. Backlash of the system can be achieved in particular by the fact that between the stand and bearing block, an elastic element is arranged, which exerts a force on the stand and bracket, which presses apart the stand and the bearing block in the direction of displacement. This elastic element is preferably a helical spring.

For displacement of the stand and bearing block, a motor can be provided which actuates the displacement means (threaded spindle)

Fig. 1

schematisch ein zu schweißendes Rohr in Richtung der Längsachse des Rohres betrachtet, das von zwei Walzen (Seitenschließern) geführt wird;

Fig. 2

eine perspektivische Ansicht des Seitenschließergerüsts einer Rohrschweißanlage;

Fig. 3

die Vorderansicht des Seitenschließergerüsts, teilweise geschnitten dargestellt;

Fig. 4

eine vergrößerte Ansicht der Gewindespindel zur Verschiebung von Ständer und Lagerbock; und

Fig. 5

eine Seitenansicht einer anderen Ausführung eines Seitenschließergerüsts.

In the drawing, an embodiment of the invention is shown. Show it:

Fig. 1

schematically considered a tube to be welded in the direction of the longitudinal axis of the tube, which is guided by two rollers (side closers);

Fig. 2

a perspective view of the side closing frame of a pipe welding system;

Fig. 3

the front view of the side closure framework, shown partially cut;

Fig. 4

an enlarged view of the threaded spindle for the displacement of the stator and bearing block; and

Fig. 5

a side view of another embodiment of a Seitenschließergerüsts.

In Fig. 1 is shown schematically how a formed from a flat metal strip tube 1 is produced. The flat metal strip runs in the direction of the longitudinal axis 8 of the tube 1 and is formed in upstream stations to the tube 1. In Fig. 1 the state is sketched, as it arises shortly before the welding process: The tube 1 is held and guided by two rollers 4 and 5, which are referred to as side-closing. The rollers 4 and 5 rotate about vertically arranged axes 10 and 11. Due to their contour, the rollers 4, 5 comprise the tube 1 each over a peripheral portion of almost 180 °. Above is the seam 2, where the tube 1 is welded together.

To ensure an optimal production result, it is necessary that the tube 1 is guided as accurately as possible and so that the longitudinal axis 8 lies in the theoretical center plane XX. For this purpose, the two rollers 4 and 5 relative to each other and with respect to the center plane XX in the displacement directions A and B symmetrically delivered or adjusted.

The Figures 2 and 3 show the construction concept of a side closing stand 3, in which the rollers 4 and 5 are mounted. The side closer frame 3 has in this embodiment a fixedly arranged base frame 6. On the base frame 6, a stand 7 is slidably disposed. For this purpose 7 play-free linear guides 22 are provided between the base frame 6 and stand. With these, the stand 7 can be moved in the direction of displacement A on the base frame 6. Thus, the roller 4 is set with respect to the center plane XX of the tube 1.

The stator 7 has - viewed in the direction of the longitudinal axis 8 of the tube 1 - a U-shaped contour. The bearing of the roller 4 is arranged on a leg 20 of the "U". A bearing block 9 is supported on the other leg 21 of the "U" in the horizontal direction. The bearing block 9 is slidably mounted on the stand 7. For this purpose, 9 play-free linear guides 23 are provided between stand 7 and bearing block. The displacement direction B, in which the bearing block can move relative to the stator 7 and thus also with respect to the center plane X-X of the tube 1, is basically oriented in opposite directions to the displacement direction A.

A magnitude same, but opposite movement of the stator 7 and bearing block 9 in the direction A or B in the way that the rollers 4 and 5 are always arranged symmetrically to the center plane XX is effected by a threaded spindle 12. Their detailed structure is in Fig. 4 to see.

The threaded spindle 12 has a first portion 13 which is arranged with a fixed bearing 27 in a carrier 26; the spindle 12 is thus rotatable but axially fixed in the carrier 26. The carrier 26 is fixedly connected to the base frame 6; Base frame 6 and support 26 thus form a functional unit. The threaded spindle 12 further includes a second portion 14 and a third portion 17. The second section 14 is provided with a first thread 15, the third section 17 with a second thread 18. The threads 15 and 18 cooperate with respective threaded nuts 16 and 19, respectively. The one thread nut 16 is fixedly arranged in the stator 7, the other nut 19 fixed in the bearing block 9. The spindle 12 is driven by a motor 25 driven.

Although the threads 15 and 18 have the same pitch, but different direction of rotation, d. H. one thread is designed as a right-hand thread, the other as a left-hand thread. This results in the following:

If the threaded spindle 12 is rotated by the motor 25 or by hand, by the two threads 15 and 18 of the stator 7 and the bearing block 9 by equal amounts relative to the base frame 6 toward each other or moved away from each other. In Fig. 4 is indicated by the displacement directions A and B, that here is a distance between the two elements 7 and 9 from each other. The entire side closer framework 3 is (see. Fig. 3 ) designed so that thereby stand 7 and bearing block 9 and with them the rollers 4 and 5 move symmetrically to the center plane XX.

To exclude any adjustment inaccuracy, which can be caused for example by different roll diameters, can be in accordance with the in Fig. 5 illustrated construction of a side closing frame 103 and the base frame 107 receiving the rollers 107 with base in a horizontal plane and transverse to the longitudinal axis of the tube. This ensures that the center of the caliber of the two rolls 4, 5 can be brought into conformity with the longitudinal axis 8 of the pipe (cf. FIG. 3 ). For this purpose, the base frame 106 is arranged displaceably on a horizontal guide 28 of a guide bed 29 here. The shift of the base frame 106 and thus the two rollers 4,5 together in one direction can be made manually by means of an adjusting spindle 30.

In this way, it is ensured by either opposing adjustment of the rollers 4,5 by means of the threaded spindle 12 and / or displacement of the entire base frame 106 that the tube 1 is always performed exactly in the center plane XX, which is the prerequisite that the welding process with highest precision can be made and pipes can be made with tight diameter tolerances.

Important in this context is the freedom of movement of the entire system. For this purpose, on the one hand precise linear guides 22 and 23 are used, which operate as free of play as possible. Furthermore, between the stator 7 and bearing block 9, a coil spring is arranged, which presses these two elements 7 and 9 away from each other. The spring-loaded system is thus free of play.

The proposed means 12 or 28,30 to the shift here keeps the rollers 4 and 5, regardless of the adjustment always exactly on the tube center (XX). Thus, the prerequisite is created to manufacture precision tubes without high production costs.

LIST OF REFERENCE NUMBERS

1

pipe

2

join

3, 103

Side closer framework

4

roller

5

roller

6, 106

base frame

7, 107

stand

8th

Longitudinal axis of the tube 1

9

bearing block

10

Axle of the roller 4

11

Axle of the roller 5

12

Means for displacement (threaded spindle)

13

first section of the threaded spindle

14

second section of the threaded spindle

15

first thread

16

threaded nut

17

third section of the threaded spindle

18

second thread

19

threaded nut

20

Thighs of the U

21

Thighs of the U

22

linear guide

23

linear guide

24

elastic element (coil spring)

25

engine

26

carrier

27

fixed bearing

28

horizontal leadership

29

guide bed

30

adjusting spindle

A

displacement direction

B

displacement direction

X X

midplane

Claims (15)

1. A pipe welding device with which a pipe (1) formed from a flat metal strip is welded to the resulting joint (2), which comprises a side closer framework (3, 103) containing at least two rollers (4, 5) which each partially embrace the metal strip formed into the pipe (1) and the side closer framework (3, 103) comprises: a base frame (6, 106), a stand (7, 107) on which one roller (4) is rotatably arranged, wherein the stand (7, 107) is arranged on the base frame (6, 106) so that it can be displaced (A) transversely to the longitudinal axis (8) of the pipe (1), and a bearing block (9) on which one roller (5) is rotatably arranged, wherein the bearing block (9) is arranged on the stand (7, 107) so that it can likewise be displaced (B) transversely to the longitudinal axis (8) of the pipe (1), characterised in that between the base frame (6, 106), the stand (7, 107) and the bearing block (9) there are provided means (12) which allow a simultaneous and oppositely directed displacement (A, B) of the stand (7, 107) or bearing block (9) relative to the base frame (6, 106).
2. The pipe welding device according to claim 1, characterised by a threaded spindle (12) as displacement means.
3. The pipe welding device according to claim 2, characterised in that with a first section (13), the threaded spindle (12) is mounted rotatably and axially fixedly in the base frame (6, 106).
4. The pipe welding device according to claim 2 or 3, characterised in that in a second section (14), the threaded spindle (12) comprises a first thread (15) which communicates with a threaded nut (16) fixedly arranged in the stand (7, 107).
5. The pipe welding device according to any one of claims 2 to 4, characterised in that in a third section (17), the threaded spindle (12) comprises a second thread (18) which communicates with a threaded nut (19) arranged fixedly in the bearing block (9).
6. The pipe welding device according to claim 4 and 5, characterised in that one of the two threads (15, 18) is a right-handed thread and the other is a left-handed thread.
7. The pipe welding device according to claim 6, characterised in that the pitches of the two threads (15, 18) are the same size.
8. The pipe welding device according to any one of claims 1 to 7, characterised in that the means (12) always holds the roller (4) arranged on the stand (7, 107) and the roller (5) arranged on the bearing block (9) symmetrically to a plane (X-X) which is perpendicular to the direction of displacement (A, B) of the stand (7, 107) and bearing block (9) and comprises the longitudinal axis (8) of the pipe (1).
9. The pipe welding device according to any one of claims 1 to 8, characterised in that the stand (7, 107) has a U-shaped configuration.
10. The pipe welding device according to claim 9, characterised in that a roller (4) is arranged in the area of a first U leg (20).
11. The pipe welding device according to claim 9 or 10, characterised in that the bearing block (9) is arranged in the area of the second U leg (21).
12. The pipe welding device according to any one of claims 1 to 11, characterised in that low-play, preferably play-free linear guides (22, 23) are arranged between the base frame (6, 106) and the stand (7, 107) and between the stand (7, 107) and the bearing block (9).
13. The pipe welding device according to any one of claims 1 to 12, characterised in that an elastic element (24) is arranged between the stand (7, 107) and the bearing block (9), which exerts a force on the stand (7, 107) and the bearing block (9) which presses the stand (7, 107) and the bearing block (9) apart in the direction of displacement (A, B).
14. The pipe welding device according to claim 13, characterised in that the elastic element (24) is a helical spring.
15. The pipe welding device according to any one of claims 5 to 14, characterised in that the means (12) for displacement (A, B) of the stand (7, 107) or bearing block (9) are driven by a motor (25).

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