DE2655019C2 - Tear-open cover made of sheet metal, in particular full-open cover, and process for its production - Google Patents

Description

The invention relates to a tear-open cover made of sheet metal, in particular a full tear-open cover with the features of the preamble of claim 1, and a method for its production with the features of the preamble of Claim 2.

In the case of tear-open lids, the tear-open areas delimited by the score lines when tearing open the the lid part remaining on the container and on the entbo Removable tear-open part causes considerable problems for tear-open edges. On the one hand, there is especially one Fully tear-open lid, which should, if possible, reveal the entire cross-section of the container for easy emptying to facilitate the often relatively fixed content, t » the risk that the tear edge remaining on the container will prevent the contents from being removed due to its roughness made much more difficult. On the other hand, there is above all the risk of injury at the tear edges, which are relatively sharp-edged and rough.

Numerous proposals have already been made to address the problems emanating from the tear edges and Overcoming disadvantages. These measures also include the formation of a closed S-shape Fold in the top sheet, the fold positioned with respect to the score line or line of weakness and is so designed in its course that the one bending edge of the sheet metal fold after the tear-open part has been torn open the tear edge remaining on the part having the sheet metal fold is slightly in the radial direction covered and thus effective as protection against accidental contact. So it is known, for example, such a sheet metal fold ar. to form the ring-shaped cover mirror part, which remains on the container after opening the cover (cf. US-PS 33 03 958). The bending edge can be seen from the outside over the tear edge remaining on the container or be arranged below this.

A sheet metal fold of this kind with a full tear-open lid is also shown in US Pat. No. 3,696,961. This also shows the process for producing the Biechfaite. To do this, First, the sheet metal blank is formed into a preform, the outside of which is necessary for the tight connection of the Has the lid with the container serving folded edge, on which the usual core wall joins inwards, its lower end with the central cover mirror section via a profiled and to the core wall is connected approximately parallel intermediate section. This preform is then used in a second Step so upset that it has an open S-shaped Cross-section received.

Thereafter, in the central cover mirror section adjacent to the upper leg of the S-shaped The score line is embossed in the intermediate section. After this step, the S-shaped open intermediate section becomes closed between legs in the axial direction to form a sheet metal fold.

Such a measure is known in the Cases an effective protection against contact for the tear edge remaining on the container after opening created. In order to also provide protection against contact for the tear edge remaining on the tear-open part, additional measures are required.

One measure is that the sheet metal fold instead of the ring-shaped one remaining on the container Provides sheet metal part on the central cover surface area so as to protect against contact for the tear-open part remaining tear edge, while the contact protection for the remaining on the container Tear edge is created by a corresponding radial fold-like indentation of the container body (cf. DE-OS 23 12 432 or DE-OS 23 08 986).

In all these cases, if a protection against contact is created for both resulting tear edges is to be, in addition to the sheet metal fold in the lid, further measures are required, which increases the cost of materials and significantly increases the manufacturing time and cost.

Starting from a tear-off lid that is in compliance with US-PS 33 03 958 has the features of the preamble of claim I or of a Manufacturing process for such a lid, which in accordance with US-PS 36 96 961 the features of the preamble of claim 2, it is the object of the invention to so weiterzu- the tear-open cover. form that with the same material and manufacturing effort a contact protection for both tear edges ^ e-

is guaranteed and in the production of a tear-off lid with protection against accidental contact for both tear edges of the The cost of materials and the manufacturing effort and the manufacturing costs can be significantly reduced.

This object is achieved by designing the tear-open cover with the features of claim 1 or by the formation of the production method according to the features of claim 2 solved.

Due to this solution, a protection against contact is simultaneously for the remaining on the container and for the The tear edge remaining on the tear-open part is achieved with just a single sheet metal fold in the lid Protection against contact for one of the two tear edges can therefore be dispensed with. It also takes No special processing steps, for example on the container body, as well as the protection against accidental contact for the second tear edge to train. Since only the steps for forming the sheet metal fold are required, this also results a much simpler production and a lower cost of the tear-open cover, since additional production steps and materials for further protection against accidental contact are dispensable.

Due to the new design, there is also a known contact protection against the known contact protection formed by a sheet metal fold the advantage achieved that the tear edge in each case at a much larger radial distance comes to lie from the associated bending edge of the sheet metal fold than is possible with the previous sheet metal folds was.

The new manufacturing process in particular offers the particular advantage here of contact protection with only one sheet metal fold to be able to guarantee for both tear edges. The new process is designed in such a way that that the one which is subject to deformation during the production of the sheet metal fold and which has the score line The area of the intermediate section is not subject to excessive tensile stress, but rather under constant stress Upsetting pressure is held.

The sheet metal fold can be placed very close to the core wall, with the sheet metal fold adding the score line protects against the effects of external forces that lead to a premature collapse of the score lines could.

The breaking of the score line to open the lid is also easy with the new lid design possible, e.g. B. with a tab which is designed similarly. like the grip tab according to FIGS. 9 and 10 U.S. Patent 3,696,961, cited above.

The invention is explained in more detail below with the aid of schematic drawings of an exemplary embodiment explained. It shows

F i g. 1 shows a plan view of the tear-open lid with the features according to the invention;

F i g. 2 to 4 each in the detail and in the vertical section different steps and the associated Tools that are used in the manufacture of the new cover according to FIG. 1 are provided;

F i g. 5 in the cutout and on a larger scale, the edge area of the cover according to FIG. 1 in closed State;

FIG. 6 shows the position in a representation similar to FIG. 5 the parts at the beginning of the break-in when opening the lid and

7 and 8 each in a detail and in vertical section the container and the tear-off part with associated Tear edge after opening the container.

The cover 1 shown in Fig. I consists of sheet metal.

As the manufacturing stages according to Fig. 2 to 4 show, the cover has an outer edge flange 5 nrt cover hook 6 serving for sealing connection with the fuselage, to which a core wall 4 adjoins inside, which surrounds the cover mirror 3 at a small distance from the Core wall 4 runs in the cover area a closed S-shaped sheet metal fold 7 with parallel upper leg 7a, middle leg Tb and lower leg 7c, all of which run parallel to each other and to the cover area 3 and each other via bending edges 7c / or. 7e are connected.

A score line 8 is embossed in the middle leg Tb , which runs parallel to the core wall 4 and is self-contained. The score line, which forms a line of weakness in the sheet metal, is at a distance from both bending edges Td and 7e, these distances remaining essentially the same over the circumference of the cover. The score line 8 forms in the lid mirror 3. ^ A tear area 9 to which a lever-shaped grip tab 2 is attached by means of rivets 11 a, 11 b.

The grip tab 2 is in its length; ■ ohtung as a rigid lever formed and has at its "Adial outer end a Aufbrechnase 2a and at the opposite end an annular handle portion 2c The opening 12 for the rivet is in one of the body. Separate 1.er grip tab 2 by a cut line 13 Fastening tab is provided, which is connected to the body of the grip tab via a bending zone near the break-open nose 2a. The grip tab body is denoted by 2b .

As shown in FIG. 5, the break-open nose of the grip tab has one over the fastening plane of the Gripping tab on the tear-off portion 14 protruding downwards, the lower edge 15 of which into the gap engages between the core wall 4 and the bending line 7a of the sheet metal fold 7 to create an abutment when the handle end 2c is lifted on the lid surface near the lower end of the core wall, around which the grip tab according to F i g. 6 can be swiveled upwards in order to break in the score line 8. After breaking in the score line can be the tear area 9 in the usual way by pulling on the handle end 2c of the The grip tab must be torn open and separated from the container.

After the opening process, the bending edge Td forms an effective contact protection for the tear edge remaining under the upper leg 7a, while the bending edge Te forms an effective contact protection against the tear edge offset radially outwards and directly above the lower leg Tc .

In the production of the tear-open cover, a sheet metal blank is used as the starting point and a preform is produced from the preform, the cross-sectional shape of which is shown in FIG. It can be seen that the preform has an intermediate section 3c between the lower end of the core wall 4 and the central cover mirror section 3a. The intermediate section is profiled and has a lower leg 36, adjoining the core wall 4, approximately parallel to the central mirror section 3a, and a section 3d parallel to it and located in the axial direction between the central mirror section 3, 7 and the lower section 3b. Close on both sides of section 3d

bi sections 3e and 3f which are approximately parallel to the ceiling axis. After the preform has been produced, a score line 8 is embossed in section 3dd.

The preform is then made according to FIG. 2 in one

a profiled inner recess having lower punch 21 inserted, which the central portion 3a. the core wall 4 and the adjoining section 36 are supported from below. With a lowerable ring punch 22, the sections 3e 3c / and 3 / \ are now formed in such a way that they assume a position parallel to the axis of the cover, the section 3d containing the score line 8 and the section 3 / adjoining it on the outside during the forming be compressed by Verkleine-.Li _c their diameter. This simultaneous upsetting and deformation ensures that tensile stress on the sheet metal material in the deformation area, which would cause the score line 8 to break in prematurely, is excluded.

From the intermediate state according to FIG. 3, the intermediate section to the sheet metal fold 7 is closed with the aid of the punch arrangement according to FIG. In the device according to FIG. 4, the lower punch consists of an outer punch ring 416 fixed to the frame and an axially resilient central punch 41a which tapers in the shape of a truncated cone at 45 upward. During the closing of the fold, these two lower punches support the lower limb, which closes on the core wall 4, and the central mirror section. The upper punch assembly has a ring punch 426 engaging with a tight fit in the core wall, the radial inner surface 44 of which acts as an abutment for the outer bending edge Td during the closing of the fold. The importance of this measure during the forming process is explained below. A central punch 42a engages in the ring punch 426, which sits snugly on the top of the central mirror section and bridges the annular gap between the central mirror section 3a and the ring punch 426. The intermediate section to the fold 7 is axially closed by the axial pressure of the ram 42a, as shown in phantom in FIG. 4 is indicated in steps.

It can be seen from FIG. 4 that the largest diameter of the central lower punch 41a is smaller than that Diameter of the section 3c containing the score line 8 according to FIG. 3. The outer ring punch 426 is in relation to the diameter of its inner guide surface 44 in relation to the position and the dimension of the section 3c of the cover is designed so that the upper bending edge 46 of the section 3c is in front Reaching the closed position of the fold rests on the guide surface 44. With further pressure by the central punch 42a, the sections 3c and 36 are reduced while reducing the original Diameter of the section 3c compressed radially inwards, as shown in FIG. 4 shows. Through this, with the help of the Ring punch 426 taking place, radial upsetting of the section having the score line will take care of this worn so that this section of the sheet metal fold during the closing of the fold in turn no premature Break in the kerbünie 8 favoring tensile stresses is exposed.

After the fold has been closed, the tab 2 is attached to the tear-open part with the aid of the rivet 11a, M6.

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For this purpose 2 sheets of drawings

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Claims (3)

Patent claims: 1. Tear-open lid made of sheet metal, in particular a full-open lid, with a tear area bounded by a weakening line in the lid mirror, to which a lever-like tab is attached to break through the weakening line and tear open the lid, with a closed S-shaped sheet metal fold running along the weakening line in the lid area is arranged so that a bending edge of the sheet metal fold acts as a protection against contact with a tear edge that occurs when the lid is torn open, characterized in that d ^: e weakening line (8) at a distance from both bending edges (7d, 7e) of the S-shaped fold in whose middle leg (7 b) is arranged. 2. A method for producing a tear-open lid according to claim 1, in which initially from a sheet metal blank a preform having a core wall, an outer cover flange, and one from the lower end profiled intermediate section extending from the core wall and approximately parallel to the core wall is formed, which is in the central cover mirror section passes over, whereupon the line of weakness is impressed, and the profiled intermediate section in is closed in the axial direction to form a fold, characterized in that the profiled intermediate section initially with a lying at an axial distance from both the lower end of the core wall and from the zenfilen cover surface, for The cover axis is provided with a vertical wall section and the weakening line is embossed into this, whereupon the intermediate section in ehen to the cover axis parallel wall section of one of the diameter of the central cover mirror section formed corresponding diameter and only then the intermediate section is axially closed to the fold will. 3. The method according to claim 2, characterized in that the line containing the weakening Wall section, which during the closing of the fold from its position parallel to the cover axis into a is deformed position perpendicular to the cover axis, during this deformation at the same time with reduction its inner diameter is compressed radially inward.