GB1559858A

GB1559858A - Method and apparatus for continuous forming of a strip material

Info

Publication number: GB1559858A
Application number: GB3128776A
Authority: GB
Original assignee: Mannesmann AG
Current assignee: Vodafone GmbH
Priority date: 1975-08-11
Filing date: 1976-07-27
Publication date: 1980-01-30
Also published as: JPS5221253A; JPS543057B2; IT1067352B; FR2333591B1; FR2333591A1; DE2536125A1

Description

(54) A METHOD AND AN APPARATUS FOR CONTINUOUS FORMING OF A STRIP MATERIAL (71) We, MANNESMANN AKTIEN GESELLSCHAFT, a German body corporate of Mannesmannufer 2, 4000 Dusseldorf 1, German Federal Republic, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention relates to a method and apparatus for the continuous formation of planar strip material into tubular sections; e.g. a tube, having a longitudinal slit which is either left open or is closed by longitudinal seam welding.

In the production of slotted tubes in this manner, bending of the strip material is effected by stepwise cylindrical rolling through roll stands. In known such methods, each bending tool is useful only in the production of a tube of a given diameter, so that the welding capacity is badly utilised with small batches, since the installation has to be re-designed for the respective diameters. This also involves a considerable and therefore costly storage of tools.

The present invention aims to provide a method of continuously forming a planar strip material into a tube in which the ultimate tube diameter may be altered merely by varying the lateral dimension of the strip and without requiring any stand or stands to be modified. The method of the invention comprises passing the strip material through a succession of roll stands to form a slit polygonal tube section, at least the first stand including horizontally spaced rolls for forming two corners of said section, the spacing of the rolls being adjustable, wherein the lateral dimension of the strip is monitored at the entrance to the first stand and the spacing of the rolls in such stand adjusted accordingly.

Apparatus for carrying out the method of the invention includes a succession of roll stands, at least the first of which comprises horizontally spaced rolls having mutually inclined edge surfaces for forming at least one edge of said polygonal tube section, the spacing of the rolls being adjustable; and means at the entrance to the first stand for monitoring the lateral dimension of a said strip material, which monitoring means are coupled to a control device for adjusting the spacing of the rolls in the first stand according to said monitored dimension.

By the method of the invention tubes of different dimensions can be continuously and successively formed by varying the lateral dimension of the basic strip material.

Conveniently, two strips of different constant lateral dimension may be connected by a transition strip of trapezoidal shape whereby two tube lengths of different diameter connected by a conical portion are produced in a continuous process. Such a transition strip is preferably 1 to 2 metres in length.

Shaping to round cross-section may take place after the polygonal section has been welded. The corners of the polygonal section, normally angular and having an odd number of sides, are preferably formed rounded for this purpose.

Systems for monitoring the dimensions of the strip material are of known design and typically include guide rollers engaging the strip upstream of each roll stand. Electrical or mechanical feelers or sensors may be used instead of or in addition to such guide rollers. The spacing of the roll in each stand is adjusted in response to signals generated by the monitoring system upstream thereof.

Arranged downstream of the roll stands and possibly of the welding station is a round pass, with which the polygonal section is rolled into a round section or section member.

The slit polygonal tube section produced by the method of the invention can be very accurately guided by virtue of its cress- section, so that welding can be carried out at speeds considerably above those employed at present with high-frequency welding and hence throughput times can be obtained which enable a better and more economic production of the profile or section members.

The continuous working procedure saves the re-designing of the stands. By obviating the relative speeds greater than zero between the strip and rolls, better surfaces are produced in the section members. Substantially straight edges are produced in the method of the invention, which simplifies the welding step.

Each first roll stand in apparatus according to the invention comprises a pair of upper and a pair of lower rolls mounted on horizontal axes on which the roll position may be adjusted in one embodiment, these rolls are flanked by slabbing rolls, which may however be foregone in another embodiment by forming the bottom rolls with profiled edges which form a corner of the polygonal cross-section as the strip material passes thereover.

Two embodiments of apparatus according to the invention will now be described with reference to the accompanying drawings, wherein: Figure 1 shows a first set of forming rolls in a first embodiment of the invention (e.g.

for a pentagonal profile); Figure 2 shows a second set of forming rolls similar to those illustrated in Figure 1 but at a different spacing; Figure 3 shows a third set of forming rolls forming the pentagonal cross-section; Figure 4 shows the completed pentagonal cross-section in the welding position; Figure 5 shows the first set of forming rolls in a second embodiment with profiled bottom rolls; Figure 6 shows a second set of forming rolls similar to those illustrated in Figure 5 but at a different spacing; Figure 7 shows the pentagonal crosssection which is formed by a single top and bottom roll; and Figures 8 and 9 show the transitions to different strip widths.

Each roll stand illustrated in Figures 1 and 2 comprises top rolls 2 and bottom rolls 3, the rolls 2 and 3 being arranged for infinitely variable horizontal adjustment as regards width spacing and the top rolls 2 being in addition adjustable in height. The forming rolls include in addiion side rolls 4 set at an angle. Monitoring means (not shown) scan the strip 1 at the entrance to each roll stand and the horizontal spacing of the rolls therein is adjusted accordingly.

Figure 3 shows the further forming operation with obliquely arranged fixed support rolls 5 and a middle roll 6.

The final form of the profile member 8 is produced in stand shown in Figure 4, in which are arranged adjustable slabbing rolls 7 acting on the periphery of the profile or section member.

In the roll stand of the second embodiment shown in Figure 5, the bottom rolls 9 are profiled, i.e. they are provided with a round profile corresponding to the rounded edges of the polygonal profile which is to be formed. The further shaping of the strip 10 is effected in a second stand which is shown in Figure 6 and in which the bottom rolls 11 are likewise profiled. The development of a pentagonal profile is effected in the stand which is shown in Figure 7, the bottom roll 12 having an appropriate profile. This is followed by the forming of the final profile, as has already been illustrated in Figure 4. The top rolls 13, 14, 15 in the individual stands correspond substantially to the top rolls 2 and 6 in Figures 1 to 3.

The shape of planar strip material from which to successively produce tubes of different constant diameter is shown in Figures 8 and 9, a transition piece of trapezoidal shape xetending between two pieces of constant lateral dimension. As such a planar strip material is fed to the apparatus, the monitoring means detects the changing lateral dimension and the spacing of the rolls in the stands of Figures 1 and 2, or Figures 5 and 6, is adjusted accordingly.

For example, guide rollers (not shown) may be arranged before the stands, the guide rollers not only detecting the lateral dimension, but also ensuring that the edges of the strip are located properly for entrance into the stands. The driving of the strip can be effected in known manner by driving the rolls or by pulling the strip through the stands.

WHAT WE CLAIM IS: 1. A method of continuously forming a planar strip material into a tube of changing cross-section comprising passing the strip material through a succession of roll stands to form a slit polygonal tube section, at least the first stand including horizontally spaced rolls for forming two corners of said section, the spacing of the rolls being adjustable, wherein the lateral dimension of the strip is monitored at the entrance to the first stand and the spacing of the rolls in such stand adjusted accordingly.

2. A method according to Claim 1 wherein each said corner is formed rounded.

3. A method according to Claim 1 or Claim 2 wherein said slit polygon is regular and has an odd number of sides.

4. A method according to any preceding Claim including the step of welding the slit in the tube section.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. accurately guided by virtue of its cress- section, so that welding can be carried out at speeds considerably above those employed at present with high-frequency welding and hence throughput times can be obtained which enable a better and more economic production of the profile or section members. The continuous working procedure saves the re-designing of the stands. By obviating the relative speeds greater than zero between the strip and rolls, better surfaces are produced in the section members. Substantially straight edges are produced in the method of the invention, which simplifies the welding step. Each first roll stand in apparatus according to the invention comprises a pair of upper and a pair of lower rolls mounted on horizontal axes on which the roll position may be adjusted in one embodiment, these rolls are flanked by slabbing rolls, which may however be foregone in another embodiment by forming the bottom rolls with profiled edges which form a corner of the polygonal cross-section as the strip material passes thereover. Two embodiments of apparatus according to the invention will now be described with reference to the accompanying drawings, wherein: Figure 1 shows a first set of forming rolls in a first embodiment of the invention (e.g. for a pentagonal profile); Figure 2 shows a second set of forming rolls similar to those illustrated in Figure 1 but at a different spacing; Figure 3 shows a third set of forming rolls forming the pentagonal cross-section; Figure 4 shows the completed pentagonal cross-section in the welding position; Figure 5 shows the first set of forming rolls in a second embodiment with profiled bottom rolls; Figure 6 shows a second set of forming rolls similar to those illustrated in Figure 5 but at a different spacing; Figure 7 shows the pentagonal crosssection which is formed by a single top and bottom roll; and Figures 8 and 9 show the transitions to different strip widths. Each roll stand illustrated in Figures 1 and 2 comprises top rolls 2 and bottom rolls 3, the rolls 2 and 3 being arranged for infinitely variable horizontal adjustment as regards width spacing and the top rolls 2 being in addition adjustable in height. The forming rolls include in addiion side rolls 4 set at an angle. Monitoring means (not shown) scan the strip 1 at the entrance to each roll stand and the horizontal spacing of the rolls therein is adjusted accordingly. Figure 3 shows the further forming operation with obliquely arranged fixed support rolls 5 and a middle roll 6. The final form of the profile member 8 is produced in stand shown in Figure 4, in which are arranged adjustable slabbing rolls 7 acting on the periphery of the profile or section member. In the roll stand of the second embodiment shown in Figure 5, the bottom rolls 9 are profiled, i.e. they are provided with a round profile corresponding to the rounded edges of the polygonal profile which is to be formed. The further shaping of the strip 10 is effected in a second stand which is shown in Figure 6 and in which the bottom rolls 11 are likewise profiled. The development of a pentagonal profile is effected in the stand which is shown in Figure 7, the bottom roll 12 having an appropriate profile. This is followed by the forming of the final profile, as has already been illustrated in Figure 4. The top rolls 13, 14, 15 in the individual stands correspond substantially to the top rolls 2 and 6 in Figures 1 to 3. The shape of planar strip material from which to successively produce tubes of different constant diameter is shown in Figures 8 and 9, a transition piece of trapezoidal shape xetending between two pieces of constant lateral dimension. As such a planar strip material is fed to the apparatus, the monitoring means detects the changing lateral dimension and the spacing of the rolls in the stands of Figures 1 and 2, or Figures 5 and 6, is adjusted accordingly. For example, guide rollers (not shown) may be arranged before the stands, the guide rollers not only detecting the lateral dimension, but also ensuring that the edges of the strip are located properly for entrance into the stands. The driving of the strip can be effected in known manner by driving the rolls or by pulling the strip through the stands. WHAT WE CLAIM IS:

1. A method of continuously forming a planar strip material into a tube of changing cross-section comprising passing the strip material through a succession of roll stands to form a slit polygonal tube section, at least the first stand including horizontally spaced rolls for forming two corners of said section, the spacing of the rolls being adjustable, wherein the lateral dimension of the strip is monitored at the entrance to the first stand and the spacing of the rolls in such stand adjusted accordingly.

2. A method according to Claim 1 wherein each said corner is formed rounded.

5. A method according to any preceding

Claim including the step of forming the polygonal section into a tube of circular cross-section.

6. A method according to any preceding Claim wherein the planar strip material is a transition strip of trapezoidal shape extending between two strips each of constant lateral dimension whereby two tube lengths of different diameter connected by a conical portion are produced in a continuous process.

7. A method of continuously forming a planar strip material into a tube of changing cross-section substantially as described herein with reference to and as illustrated by the accompanying drawings.

8. Apparatus for carrying out a method according to any preceding Claim including a succession of roll stands, at least the first of which comprises horizontally spaced rolls having mutualy inclined edge surfaces for forming at least one edge of a said polygonal tube section, the spacing of the rolls being adjustable: and means at the entrance to the first stand for monitoring the lateral dimension of a said strip material, which monitoring means are coupled to a control device for adjusting the spacing of the rolls in the first stand according to said monitored dimension.

9. Apparatus according to Claim 8 wherein the rolls in each stand are arranged symmetrically about a vertical plane.

10. Apparatus according to Claim 8 or Claim 9 including a round pass following the stands for the formation of the polygonal section into a tube of circular cross-section.

11. Apparatus according to any of Claims 8 to 10 including a welding station for welding a said polygonal tube section along its slit.

12. Apparatus according to any of Claims 8 to 11 including means for driving the rolls.

13. Apparatus according to any of Claims 8 to 12 wherein each monitoring means comprises guide rolls arranged before the respective stand.

14. Apparatus according to any of Claims 8 to 13 including a first stand having a pair of top forming rolls and a pair of bottom forming rolls cooperating therewith, the rolls being rotatable about horizontal axes and the horizontal spacing of the rolls in each pair being adjustable and the bottom rolls being provided with a round profile on their periphery; and a last stand having a profiled bottom and top roll, both rotatable along a horizontal axis and arranged in a common vertical plane.

15. Apparatus for contiuuously forming a planar strip material into a tube of changing cross-section according to Claim 8 and substantially as described herein with reference to and as illustrated by Figures 1 to 4, or Figures 5 to 7 of the accompanying drawings.