METHOD FOR PRODUCING A ROLLED EDGE

Abstract

The invention relates to a method for producing a rolled edge from a cylindrical edge portion (11) of a pipe. In the method, a starting zone (14) of the edge portion (11) is rolled by a forcibly controlled tool (30). A flanging die (21) then advances into the rolled edge portion (11) and flanges the rolled edge portion into a roll (12). The method according to the invention is characterized in that the starting zone (14) of the edge portion (11) is folded over by the tool (30), which comprises a folding die (37) and counterholder (34), at an angle () in the range from 75-105 from the axial direction (45) into a substantially radially peripheral flange (41). The invention further relates to elements, in particular in the forme of an aerosol dome, having such rolled edges.

Claims

1. A method for producing a rolled edge from a cylindrical edge portion of a pipe, in which method in a first step a starting zone of an edge portion is rolled by a forcibly controlled tool and in a second step a flanging die then advances into the rolled edge portion and flanges this into a roll, wherein in the first step the starting zone of the edge portion is folded over by the tool, comprising a folding die and counterholder, at an angle in the range of 75-105 from the axial direction into a substantially radial peripheral flange.

2. The method as claimed in claim 1, wherein the bending radius between the peripheral flange and the adjoining axial portion is less than twice a material thickness (s) of the cylindrical edge portion.

3. The method as claimed in claim 1, wherein a radial length of the flange is in the range of 2-5 times the material thickness of the cylindrical edge portion.

4. The method as claimed in claim 1, wherein the substantially linear portion of the flange during the rolling which follows the folding over is placed by the flanging die in the interior of the roll.

5. The method as claimed in claim 1, wherein the angle is in the range of 80-100.

6. The method as claimed in claim 1, wherein the material thickness of the edge portion is in the range of 0.1-1 mm.

7. The method as claimed in claim 1, wherein the material of the edge portion is tinplate.

8. The method as claimed in claim 1, wherein the material of the edge portion is sheet steel with a yield strength, determined per DIN EN 10002-1:2001, of at least 500 MPa, and/or with a tensile strength, determined per DIN EN 10002-1:2001, of at least 500 MPa.

9. The method as claimed in claim 1, wherein the material of the edge portion is sheet steel.

10. The method as claimed in claim 1, wherein the flanging die has a wrap angle of at least 100.

11. The method as claimed in claim 1, wherein the method involves only the first and second step, and the tool comprises a plurality of outer counterholders, which are radially adjustable in regard to the pipe axis, as well as a folding die, and the rolling is done in the following steps: moving the outer counterholders radially inward until striking against the pipe portion, advancing the folding die into the pipe portion with folding over of its starting zone, removing the folding die from the pipe portion, moving the outer counterholders radially outward with axial releasing of the pipe portion.

12. The method as claimed in claim 1, wherein the rolled edge is placed on a tubular portion of an aerosol dome for spray cans to accommodate a valve plate.

13. The method as claimed in claim 1, wherein the folding die and the counterholder surround the edge portion with form fitting.

14. Method as claimed in claim 1 for making an aerosol dome for a spray can.

15. A rolled edge, produced by a method as claimed in claim 1, or a spray can having such a rolled edge.

16. The method as claimed in claim 1, wherein the bending radius between the peripheral flange and the adjoining axial portion is in the range of 0.5-1.5 times the material thickness of the cylindrical edge portion.

17. The method as claimed in claim 1, wherein the bending radius between the peripheral flange and the adjoining axial portion is in the range of 0.75-1.25 times the material thickness of the cylindrical edge portion.

18. The method as claimed in claim 1, wherein the radial length of the flange is in the range of 3-4 times the material thickness of the cylindrical edge portion.

19. The method as claimed in claim 1, wherein the substantially linear portion of the flange during the rolling which follows the folding over is placed by the flanging die in the interior of the roll, and is directed in substantially radial direction into the roll.

20. The method as claimed in claim 1, wherein the angle is in the range of 85-95.

21. The method as claimed in claim 1, wherein the material thickness of the edge portion is in the range of 0.15-0.4 mm.

22. The method as claimed in claim 1, wherein the material thickness of the edge portion is in the range of 0.18-0.34 mm.

23. The method as claimed in claim 8, wherein the material of the edge portion is sheet steel with a yield strength, determined per DIN EN 10002-1:2001, of at least 550 MPa, and/or with a tensile strength, determined per DIN EN 10002-1:2001, of at least 575 MPa.

24. The method as claimed in claim 1, wherein the material of the edge portion is tinplate of type TH520, material number 1.0384; TH550, material number 1.0373; TH580, material number 1.0382; TH620, material number 1.0374, or the corresponding TS types, each time according to DIN EN 10202: 2001, and/or DR8, DR8, DR8.5, or DR9, each time according to AISI/ASTM 623.

25. The method as claimed in claim 1, wherein the flanging die has a wrap angle of at least 120.

26. The method as claimed in claim 1, wherein the method involves only the first and second step, and the tool comprises a plurality of outer counterholders, which are radially adjustable in regard to the pipe axis, as well as a folding die, and the rolling is done in the following steps: moving the outer counterholders radially inward until striking against the pipe portion, advancing the folding die into the pipe portion with folding over of its starting zone, removing the folding die from the pipe portion, moving the outer counterholders radially outward with axial releasing of the pipe portion, wherein 3, 4, 5, or 6 outer counterholders are provided, distributed about the circumference, each of them having a radial arm and radially inward situated clamping areas, which substantially encircle and enclose the axial portion.

27. A rolled edge according to claim 15, as part of an aerosol dome for a spray can.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Preferred embodiments of the invention are described in the following with the aid of the drawings, serving only for explanation and not to be understood as limitations. The drawings show:

[0039] FIG. 1-6 the already explained figures to illustrate the relations in the prior art;

[0040] FIG. 7 a representation of an aerosol dome and a folding die as well as pusher and counterholder in two positions, namely, still undeformed at left and folded over at right, i.e., the aerosol dome having a folded-over starting zone;

[0041] FIG. 8 a plan view of the folding die;

[0042] FIG. 9 a representation of an aerosol dome in the rolling tool with flanging die, but the aerosol dome already having a folded-over starting zone;

[0043] FIG. 10 in a detailed large cut-out view per B in FIG. 9, a finally rolled rolled edge according to the invention;

[0044] FIG. 11 a detailed representation of the folded-over portion prior to the treatment with the flanging die.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0045] FIGS. 7-11 show, in various representations and in different steps of the method, the newly proposed method for producing a rolled edge, now also possibly using harder materials than the previously possible ones.

[0046] FIG. 7 shows the step of folding over the starting zone 14 in the tooling, with tooling still open at the left side, and at the right side in the condition of the tooling with the edge folded over into a peripheral flange 41.

[0047] As can be seen at the left side, the aerosol dome 10 and the axial portion 42 have respective counterholder elements 34 at the side, around the circumference, and from above a folding die 37 with a narrow radius 36 is introduced into the opening along the axis 44. The starting region 14 is folded over at a right angle and forming a relatively sharp edge, basically by a right angle or roughly 90, as can be seen on the right side in FIG. 7. FIG. 8 shows one possible tooling to perform this first operation of creating the rolled edge in a plan view. It can be seen that there are a total of 4 pushers 35, which control the counterholders 34. The counterholders 34 each have a radial arm 38, relative to the tooling axis 44, and regions 39 encircling and engaging the axial portion 42 of the workpiece by somewhat less than 90.

[0048] In the next step, the actual rolled edge is created, which is shown in FIG. 9. Once again, the condition with the tooling still open is shown at the left side, that is, in a condition where the flanging die 21 has been introduced into the opening of the prepared dome, but has not yet formed the edge region. The flanging die 21 has a relatively large wrap angle 48 of around 120. Further tooling elements, especially counterholders, can likewise be provided in this step, but are not mandatory. The flanging die 21 then advances axially into the opening and now rolls the axial portion 42 into the actual roll 12.

[0049] As can be seen in the detailed cut-out of FIG. 10, the folded-over starting zone remains basically unchanged. The almost linear folded-over region 41 and the sharp bend 40 remain basically intact, but are no hindrance, since the edge is rolled so much to form the roll 12 that the almost linear region 41 points more or less into the interior 47 of the roll 12. Thus, no disturbing or especially aesthetically problematical effects result, and also the safety is entirely assured, since an optionally sharp edge is moved into the interior of the roll.

[0050] For the functioning of the process, the material thickness and radius as well as the bending length are advantageously specifically attuned to each other. The individual parameters for this are shown in FIG. 11. On the one hand the folding angle , on the other hand the bending length q, that is, the radial extension of the flange, as well as the material thickness s. These variables are each given in terms of the axial portion 42, the almost linear region 41 and the axial direction in the region of the axial portion 42 or the radial direction 46, orwhen not exactly equal to 90the substantially radial direction (46) of the folded-over region 41.

TABLE-US-00001 LIST OF REFERENCE SYMBOLS 10 Aerosol dome 11 Pipe or edge portion of aerosol dome 12 Roll 13 Bend 14 Starting zone 15 Edge geometry 16 Annular edge 20 Forming tool 21 Flanging die 22 Radius at flanging die 30 Rolling tool 31 Rolling die 31 Radius at rolling die 32 Hold-down 34 Counterholder 35 Pusher 36 Radius at folding die 37 Folding die 38 Radial arm of 34 39 Clamping area of 34 40 Sharp bend in 12 41 Almost-linear region of 14 42 Axial portion 43 Dome portion 44 Axis of symmetry 45 Axial direction in region 42 46 Direction of folded-over region 41 47 Interior of 12 48 Wrap angle of 21 s Material thickness q Bending length r Bending radius Folding angle