EP1372880B1 - Method for producing a rolled edge - Google Patents

Description

TECHNICAL AREA
• The present invention relates to a method for producing a rolled edge according to the preamble of claim 1.
• Methods of this type are used, inter alia, in the production of so-called aerosol domes for spray bottles, wherein a tubular portion of these dome is converted to just such a roll edge for receiving a valve disk. Especially in this case, high demands are placed on the precision and thin sheets of only a few tenths of a millimeter thick are processed.
STATE OF THE ART
• In today's production of the rolled edge on the aerosol domes, a crimping die with a certain radius moves into a pipe section previously produced by pulling on the aerosol dome and crimps the edge of this pipe section into a roll. The shape and size of the rolled edge are largely determined by the geometry of the crimping die and its mentioned radius: In this forming process, however, the initial zone of the rolled edge regularly does not have the desired radius, but a more straight shape. Between the rather straight initial zone and the subsequent radially deformed zone a kind of kink arises. This effect is caused by the inherent stability of the sheet and is the more pronounced, the thinner and harder the sheet is. In addition, irregularities in the material and in the tool, which have a similar effect, and cause overall uneven, uncontrolled deformations.
• The above-described conditions are based on the FIGS. 1 . 2a) - 2e) and 3 will be shown in more detail.
• Fig. 1 shows in a longitudinal section an aerosol dome 10 with a pipe section 11 and a crimping die 21 with a radius 22 of a forming tool 20 not shown. On the left side of Fig. 1 is the initial state with the still undeformed pipe section 11 and the crimping die 21 shown in its starting position. The right part of Fig. 1 shows the hemming punch 21 in its final position. When the plunger 21 moves between the start and end positions, the tube section 11 (or, depending on the length of the tube section, at least one edge section thereof) along the radius 22 deforms into a roller 12.
• The FIGS. 2a) - 2e) each show in a detail enlargement A of Fig. 1 Details of the rolling process. Recognizable arises in the transition from Fig. 2a ) too 2b ) forming a virtually straight-line initial zone 14 of the mentioned bend 13, in the further forming process according to the FIGS. 2c) - 2e ) is unfavorably preserved. In terms of forming technology, the initial zone 14 represents an uncontrolled geometry zone. It leads to a variable height H (see FIG. Fig. 2e ) of the rolled edge 12 and thus also to an uncontrolled, irregular edge geometry 15, as shown in Fig. 3 is shown in a partial view of the reshaped aerosol dome.
• A method of the type mentioned is out US-A-4 113 133 known.
PRESENTATION OF THE INVENTION
• The inventive method is characterized by the features of claim 1.
• In this way, the sheet already receives a controlled geometry with the desired radius in the critical initial zone. Kinking is avoided. In the subsequent forming stage, this makes it possible to produce a rolled edge, which is more regular and constant in its geometry.
• The controlled rolling also causes tensile stresses, caused by the expansion of the sheet during rolling, to be more uniform over the circumference distribute the sheet edge and thus the risk of radial cracking in the sheet is reduced. This increases process reliability, which is particularly important and advantageous again in aerosol drug production.
• The proposed method can handle harder and thinner sheets, resulting in savings in raw material consumption. Here too, it is crucial in aerosol dome production, since the material costs are an important factor in view of the large quantities.
• With reference to the drawing, an embodiment of the invention, again based on the Aeorosoldom-production will be explained below. It is understood, however, that the invention is also applicable to any other pipe sections that are to be rolled.
BRIEF EXPLANATION OF THE FIGURES

Fig. 1 - 3

die bereits erläuterten Figuren zur Verdeutlichung der Verhältnisse beim Stand der Technik;

Fig. 4

in einem Längsschnitt einen Aerosoldom mit einem Rohrabschnitt in einem Anrollwerkzeug in zwei Stellungen, und zwar links noch unverformt und rechts fertig angerollt;

Fig. 5

eine Aufsicht auf das Anrollwerkzeug;

Fig.6.

eine Fig. 1 entsprechende Darstellung eines Aerosoldomes und eines Bördelstempels in zwei Stellungen, wobei eine der Aerosoldom jedoch eine bereits angerollte Anfangszone aufweist; und

Fig. 7

in einer Ausschnittsvergrösserung B von Fig. 6 im Detail einen fertig gerollten Rollrand nach der Erfindung.

Show it:

Fig. 1-3

the figures already explained to illustrate the conditions in the prior art;

Fig. 4

in a longitudinal section of an aerosol Tom with a pipe section in a roll-on tool in two positions, and left undeformed and finished rolled right;

Fig. 5

a view of the roll-on tool;

Figure 6.

a Fig. 1 corresponding representation of an aerosol dome and a crimping punch in two positions, one of the aerosol dome, however, already has an initial area rolled up; and

Fig. 7

in a detail enlargement B of Fig. 6 in detail a finished rolled roll edge according to the invention.

• In Fig. 4 is again denoted by 10 an aerosol dome with a pipe section 11, which is here, however, placed in a Anrollwerkzeug 30. This includes a Anrollstempel 31, with a radius 32, at least one hold-down 33, a plurality of counter-holder 34 and a corresponding number of slides 35. According to Fig. 5 For example, the counter-holders 34 may be configured as four radially movable segments which delimit or release a circular opening. On the left side of Fig. 4 is the initial state with the still undeformed pipe section 11 and the Anrollstempel 31 shown in its starting position. However, the parts 33 - 35 are already in their final or functional position. They reach this from a release position shown in dashed lines, by first the hold-down 33 moves together with the brackets 34 down to the stop with a ring edge 16 of the aerosol dome. Then, the slider 35 are moved down to the hold 33. By being coupled via an inclined surface with the brackets 34, they push the counter-holder 34 in this case radially inwardly to its illustrated end position for the embossing process. The right part of Fig. 4 shows the Anrollstempel 31 in its final position. When moving the Anrollstempels 31 between its start and end position, an initial portion 14 of the pipe section 11 is rolled and provided with the radius 32. Thereafter, the Anrollstempel 31 is again withdrawn from the pipe section, the slider 35 is moved upwards, the counter-holder 34 moved radially outward, the hold-down 33 moved up and released the aerosol dome 10 thereby.
• As described above, the aerosol dome 10 or its tube section 11 can subsequently be rolled in analogy to that already described with reference to FIG FIGS. 1 and 2 explained method further, wherein Fig. 6 one of the Fig. 1 corresponding representation shows. As can be seen, however, the rolled-up initial zone 14 of the tube section 11 nestles flush with the radius 22 of the crimping punch 21 in the starting position already shown on the left-hand side. For this purpose, the radii 22 of the crimping punch 21 on the one hand and 32 of the Anrollstempels 31 are preferably equally sized. During further rolling with the crimping die 21, the initial zone 14 retains its controlled radius, as shown in the detailed illustration B of FIG Fig. 6 in Fig. 7 is shown showing the finished rolled edge portion.
NAME LIST

10

aerosol dome

11

Pipe or edge section of the aerosol dome

12

role

13

kink

14

initial zone

15

edge geometry

16

annular rim

20

forming tool

21

flanging

22

Radius on the crimping punch

30

preliminary rolling

31

roll-on pad

32

Radius at the roll-on punch

33

Stripper plate

34

backstop

35

pusher

Claims (3)

1. A method for producing a rolled edge from an edge section (11) of a tube, in which method an initial zone (14) of the edge section (11) is rolled in a preliminary manner by a positively controlled tool (30) and subsequently a flanging die (21) moves into the edge section (11) and flanges the latter to form a roll (12), characterized in that the initial zone (14) of the edge section (11) is rolled in a preliminary form-fitting manner by the positively controlled tool (30) comprising a preliminary rolling die (31), having a radius (32) and pressure pads (34), and is provided with the radius (32).
2. The method as claimed in claim 1, characterized in that the tool (30) comprises a plurality of outer pressure pads (34), radially adjustable with respect to the tube axis, and a preliminary rolling die (31), and in that the preliminary rolling is carried out in the following steps:

   - adjusting the outer pressure pads (34) radially inward until they strike the tube section (11),

   - moving the preliminary rolling die (31) into the tube section (11) with its initial zone (14) being rolled in a preliminary manner,

   - moving the preliminary rolling die (31) out of the tube section (11),

   - adjusting the outer pressure pads (34) radially outward with the tube section (11) being cleared axially.
3. The method as claimed in claim 1 or 2, characterized in that the rolled edge is made on a tubular section (11) of an aerosol dome (10) for spray cans for accommodating a valve disk.

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