METHOD AND DEVICE FOR EXPANDING A METAL ELEMENT

Abstract

A method of expanding an elongated and at least regionally planar metal element that has two respective marginal regions oppositely disposed and extending in a longitudinal direction and a central region arranged therebetween and including cuts, the marginal regions of the metal element are moved apart transversely to the longitudinal direction and in parallel with a planar extent of the metal element such that connection portions of the central region formed by the cuts and connecting the two respective marginal regions to one another are folded, the method includes displacing the two respective marginal regions with respect to one another transversely to the planar extent of the metal element to form a displaced state, and subsequently moving apart the two respective marginal regions in the displaced state.

Claims

1. A method of expanding an elongated and at least regionally planar metal element that has two respective marginal regions oppositely disposed and extending in a longitudinal direction and a central region arranged therebetween and including cuts, the marginal regions of the metal element are moved apart transversely to the longitudinal direction and in parallel with a planar extent of the metal element such that connection portions of the central region formed by the cuts and connecting the two respective marginal regions to one another are folded, the method comprising: displacing the two respective marginal regions with respect to one another transversely to the planar extent of the metal element to form a displaced state; and subsequently moving apart the two respective marginal regions in the displaced state.

2. The method in accordance with claim 1, wherein a pressing tool or a rolling tool having a pressing surface has a step defining the displacing is pressed onto the metal element to displace the two respective marginal regions.

3. The method in accordance with claim 2, wherein the step is located in the region of the central portion during the pressing of the pressing tool or the rolling tool onto the metal element.

4. The method in accordance with claim 2, wherein the metal element is led between two rotatable rollers having jacket surfaces with respective steps having oppositely aligned flanks.

5. The method in accordance with claim 4, wherein the two rotatable rollers are rotated in opposite directions when leading the metal element through.

6. The method in accordance with claim 1, wherein the two respective marginal regions are displaced with respect to one another by a shape corrected displacement that corresponds to at least three times a thickness of the metal element.

7. The method in accordance with claim 1, wherein an embossed pattern is embossed in the central portion before or during the displacing of the two respective marginal regions.

8. The method in accordance with claim 1, wherein the metal element is moved in the longitudinal direction during at least one of the displacement of the two respective marginal regions or the moving apart of the two respective marginal regions.

9. An apparatus for expanding an elongated and at least regionally planar metal element, the metal element having two respective marginal regions oppositely disposed and extending in a longitudinal direction and a central region arranged therebetween and including cuts, the apparatus comprising: a stretching unit configured to hold the two respective marginal regions of the metal element and to move the two respective marginal regions apart transversely to the longitudinal direction and in parallel with a planar extent of the metal element such that connection portions of the central region formed by the cuts and connecting the marginal regions to one another are folded; a shape correction unit connected upstream of the stretching unit and configured to displace the two respective marginal regions with respect to one another transversely to the planar extent of the metal element.

10. The apparatus in accordance with claim 9, wherein the shape correction unit comprises a pressing tool or a rolling tool having a pressing surface with a step defining the displacement of the two respective marginal regions.

11. The apparatus in accordance with claim 10, wherein the pressing surface has two substantially smooth outer portions at both sides of the step and that are associated with the two respective marginal regions of the metal element.

12. The apparatus in accordance with claim 10, wherein the pressing tool or the rolling tool has at least one rotatable roller having a jacket surface with the step peripherally formed thereon.

13. The apparatus in accordance with claim 12, wherein the least one rotatable roller includes two rotatable rollers between which the metal element is configured to be led, with the steps of the jacket surfaces of the two rotatable rollers having oppositely aligned flanks.

14. The apparatus in accordance with claim 10, wherein an embossed pattern is formed on the pressing surface.

15. The apparatus in accordance with claim 9, further comprising a feed unit through which the metal element is movable in the longitudinal direction during at least one of displacement of the two respective marginal regions or the moving apart of the two respective marginal regions.

16. The apparatus in accordance with claim 9, wherein the metal element comprises galvanized steel, aluminum, or copper.

17. The apparatus in accordance with claim 9, wherein the metal element has a thickness of more than 0.5 mm.

18. The apparatus in accordance with claim 9, wherein the stretching unit has at least two clamping portions configured to hold and clamp the two respective marginal regions and an apparatus configured to automatically move apart of the clamping portions.

19. The apparatus in accordance with claim 9, wherein the apparatus comprises a pressing unit or rolling unit connected downstream of the stretching unit configured to flat press or flat roll the metal element when expanded.

20. The apparatus in accordance with claims 9, wherein the apparatus comprises an embossing unit connected upstream of the shape correction unit configured to emboss an embossed pattern in the central portion.

21. The apparatus in accordance with claim 9, wherein the shape correction unit has a combined embossing/displacement roller or roll by which both the two respective marginal regions are capable of being displaced transversely to the planar extent of the metal element and an embossed pattern is capable of being embossed in the central portion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The invention will be explained in more detail hereinafter with reference to the drawings.

[0033] FIG. 1 shows a part of a planar metal element with a cutting pattern;

[0034] FIGS. 2 to 4 show three different states in the expansion of a metal element with the cutting pattern of FIG. 1;

[0035] FIGS. 5 to 8 show a state of a metal element after the displacement of two marginal regions of the metal element transversely to its planar extent and before the expansion of the metal element;

[0036] FIG. 9 is a perspective view of a shape correction unit of an apparatus in accordance with the invention for expanding a metal element;

[0037] FIG. 10 is a side view of the shape correction unit in accordance with FIG. 9;

[0038] FIG. 11 shows a section along the line A-A in FIG. 10;

[0039] FIG. 12 is an enlarged representation of the detail B in FIG. 11;

[0040] FIG. 13 is an enlarged representation of the detail C in FIG. 10; and

[0041] FIG. 14 is a plan view of a pressing roll of the shape correction unit in accordance with FIG. 9 including a metal element acted on by the pressing roll.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] FIG. 1 shows a detail of a planar metal element 11 that has two oppositely disposed marginal regions 13 that extend along a longitudinal axis L and a central region 17 arranged therebetween and provided with cuts 15 engaging into one another. The marginal regions 13 are free of cuts, which is preferred, but not absolutely necessary. The detail shown in FIG. 1 is considerably shortened with respect to the actual length of the metal element 11. In actual fact, the metal element 11 forms a long metal strip which can have a length, for example, of several 100 m.

[0043] The metal element 11 is already described in DE 102 59 307 Al to which reference is explicitly made.

[0044] The cuts 15 are arranged such that the marginal regions 13 of the metal element 11 can be pulled apart at right angles to the longitudinal axis L, as is indicated by arrows in FIG. 1. On the pulling apart of the marginal regions 13, connection portions 19 formed by the cuts 15 are folded in the form of narrow webs along kink lines 21 so that a resulting metal element 11 having an enlarged with is generated. A corresponding folding procedure is shown in detail in FIGS. 2 to 4.

[0045] Correspondingly expanded metal elements can be used, for example, for the manufacture of sections such as are used e.g. as edge protection or as upright sections for dry walls (FIG. 7), e.g. in the form of U-sections and C-sections.

[0046] To be able to expand the metal elements 11 known per se at a high speed, as shown in FIGS. 2 to 4, an apparatus can, for example, be used such as is described in DE 10 2006 010 795 A1.

[0047] In a method in accordance with the invention of widening the metal element 11 shown in FIG. 1, the marginal regions 13 are not pulled apart at right angles to the longitudinal axis L, starting from the base state shown in FIG. 1, but are rather displaced with respect to one another beforehand in a preceding method step at right angles to the planar extent of the metal element 11. The displaced state is shown in FIGS. 5 to 8, with FIG. 5 being a side view transversely to the longitudinal axis L, FIG. 6 being a side view in the direction of the longitudinal axis L, FIG. 7 being a perspective view, and FIG. 8 being an enlarged representation of the region A in FIG. 7. It can be recognized that the two marginal regions 13 and parts of the central region 17 adjoining them extend in parallel planes 25, 26 that are spaced apart from one another, while the connection portions 19 are aligned obliquely to these planes 25, 26. An embossed pattern 27, whose generation will be described in even more detail in the following, is located in the central region 17.

[0048] The shape of the cuts 15 of the metal element 11 shown in FIGS. 5 to 8 differs slightly from the shape of the cuts 15 shown in FIGS. 1 to 4, which is, however, of no significance with respect to the displacement process.

[0049] Starting from the intermediate state shown in FIGS. 5 to 8, the marginal regions 13 are pulled apart in opposite directions, with the connection portions 19 being folded. Since the kink lines 21 are already formed in the intermediate state and since the connection portions 19 are slanted, the pulling apart can be carried out simply and with reduced pulling force. In addition no defective formation of kink lines 21 can occur. A method in accordance with the invention can therefore also be carried out for metal elements 11 having a thickness of more than 0.6 mm and for hard metal sorts.

[0050] With a conventional method for expanding a metal element 11, a displacement of the marginal regions 13 transversely to the planar extent of the metal element 11 likewise takes place since the connection portions 11 that fold over press the adjacent portions of the metal element 11 apart, as can be recognized in FIGS. 2 and 3. This is, however, an extremely brief transition state, particularly since it occurs inevitably due to the folding procedure. The invention in contrast provides that the marginal regions 13 are displaced in a direction facing transversely to the planar extent due to a targeted exertion of force and that the pulling apart of the marginal regions 13 only takes place after this targeted displacement step.

[0051] The displacement can be carried out using a shape correction unit (shape corrector) 29 shown in FIGS. 9 to 14. An apparatus in accordance with the invention for expanding a metal element 11 has, in addition to the shape correction unit 29, a stretching unit (stretcher) that is connected downstream of the shape correction unit 29, but that is not shown in FIGS. 9 to 14. The stretching unit serves to hold the marginal regions 13 of the metal element 11 and to pull them apart transversely to the longitudinal axis L and in parallel with the planar extent of the metal element 11. Specifically, the stretching unit can have clamping portions such as are disclosed in DE 10 2006 010 795 A1 engaging at the marginal regions 13.

[0052] An apparatus in accordance with the invention for expanding a metal element 11 can also comprise a pressing unit (presser) or rolling unit (roller) arranged downstream of the stretching unit for flat pressing or flat rolling the expanded metal element 11 and/or a feed unit for moving the metal element 11 along its longitudinal axis L in a feed direction R, which is likewise not shown in FIGS. 9 to 14. An apparatus in accordance with the invention for expanding a metal element 11 can furthermore comprise an embossing unit, not shown, connected upstream of the shape correction unit 29 for generating the embossed pattern 27.

[0053] The shape correction unit 29 comprises two rotatable pressing rolls 30, 31 between which the metal element 11 is led. The pressing rolls 31, 31 are rotated in opposite directions during the leading through, either passively or by a drive.

[0054] The pressing rolls 30, 31 are preferably produced from steel and have respective pressing surfaces 33 that have two smooth outer portions 35, 36 and an embossed portion 39 arranged therebetween. The embossed portions 39 of the two pressing rolls 30, 31 are shaped in a complementary manner and are aligned matching each other so that the embossed pattern 27 is not impaired by the pressing rolls 30 31 on the leading through of the metal element 11.

[0055] The smooth outer portions 35, 36 of a pressing surface 33 furthermore extend at different spacings from the axis of rotation D (FIG. 10) so that they are radially displaced. A respective step 45 is therefore formed between the smooth outer portions 35, 36 and is arranged fully peripherally on the pressing surface 33. As can in particular be seen from FIG. 12, the step 45 in the embodiment shown is superposed by the embossed portion 39 and accordingly has a plurality of flanks 47. Instead of the embossed portion 39, however, a further smooth portion could also be provided, with the step 45 then preferably being formed as a single unilateral flank. It is understood that the steps 45 of the two pressing rolls 30, 31 are formed in a complementary manner so that on the leading of the metal element 11 through the pressing rolls 30, 31, the oppositely disposed marginal regions 13 are moved apart as desired transversely to the planar extent. The displacement defined by the steps 45 in the shape correction unit 29 amounts to 5 times the thickness of the metal element 11, which has proved favorable in practice. In the shape correction unit 29 described by way of example, the pressing rolls 30, 31 are spaced apart from one another such that the metal element 11 per se is not pressed or is not pressed by an appreciable amount (FIG. 13).

[0056] The deformation of the metal element 11 by the pressing surface 33 of a pressing roll 31 can be recognized in FIG. 14.

[0057] It is generally possible to carry out the generation of the embossed pattern 27, on the one hand, and the displacement of the marginal regions 13, on the other hand, not as described in different work stations as described above, but rather in a single work station. Such a work station can have a combined embossing/displacement roll or roller that due to its shape effects the displacement of the two marginal regions 13 and the forming of the stiffening embossed pattern 27 in one and the same workstep.

[0058] The invention makes possible a folding of the connection portions 19 with a reduced force effort and with exactly defined fold edges, whereby the expansion of metal elements 11 is significantly simplified.