JP2004523377A - Symbol hidden on one side of sheet metal surface - Google Patents

Abstract

The present invention relates to a method for providing a covered symbol on a sheet-like metal surface of a beverage can. The symbol is stamped on one side of the sheet metal, but the inscription does not appear on the other side or on the sheet metal surface. The symbol (7) is applied to one side of the sheet metal (6a) to make it recognizable and readable. The area of the sheet metal, which is marked on the opposite side of the sheet metal (6b) of the stamping, is then post-stamped (10; 11; 12; 13) to form a line during the first stamping. The marked symbol (7) remains recognizable and readable on one side, but the engraving (8) from the first stamping is performed on the opposite side of the sheet metal as a result of the post-stamping (10). Cover or make unreadable.

Description

[0001]
The invention relates in particular to a method of obscuring a symbol with a thin metal plate (sheet metal) or similar surface in a two-component beverage can, and to such an engraved metal plate.
[0002]
It is frequently practiced to emboss (or otherwise engrave) characteristic symbols or other codes on thin sheets used to make the body and lid, especially for beverages. I have. Preferred methods are the stamping method or the scratch impression method. One disadvantage with this method is that the image of the symbol, sign or code appears on the back of the thin metal. Even a mirror image can be easily deciphered. This is often undesirable.
[0003]
Accordingly, it is an object of the present invention to provide a method of providing a symbol (covering symbol) covered by a thin sheet, which is preferably engraved or otherwise embossed on one side of a thin metal plate. It is to propose a method characterized by forming a symbol. The image appearing on the opposite side of the metal plate does not appear according to the invention.
[0004]
The above object is achieved by a method according to claims 1 to 14. Then, the back side (the reverse side) of the thin metal on which the image appears is subjected to a second embossing process so that the recognition and readability of the symbol embossed on one side is not impaired, while the back side of the sheet is Thus, the image is covered by subsequent embossing, making further reading and decoding impossible.
[0005]
The next embossing is a specially surface structured stamp that gives a textured or patterned inscription on the back side of the metal plate (embossing) that then reliably covers the image. This is done by using
[0006]
The first inscription can be made, for example, on the inside of a thin metal lid so that its inner surface bends inside the sealed can. Thereafter, a second stamping process is performed on the outside of the lid, which is a part of the recognizable surface of the sealed can.
[0007]
The ends of the tear-up tabs can often be opened with shaping tabs of thin sheet metal. This is advantageous in that an embossed pattern (intruding into the surface) or an inscription can be placed on the bottom side of the removable tab, which makes it unrecognizable (claim 17). The image of the symbol appearing on the upper side of the tab may be covered by a second imprint on the upper side. The stamp used for the second operation can be woven, patterned, or hatched (claim 11).
[0008]
The invention relates to a lid made from a thin metal plate (claim 10) or a part of such a surface, which needs to be retained according to claim 1 or claim 14, or is actually retained after embossing. Claim 16 can also be applied. The steps of this operation directly show how a part of the surface appears after imprinting.
[0009]
The embossing process that changes the structure on both sides is different with respect to the penetration depth and the extent of the sides (Claim 6). This second imprint changes the nature, smoothness or quality of the surface on which the first embossed image is to be masked. This first deformation is locally more pronounced, penetrates deeper into the surface material and is still recognizable after the second imprint. The quality at the surface of the image is comparable to adjacent parts of the surface that are not affected by the initial embossing.
[0010]
Both the elongation and the small depth of the surface allow the second imprinting to accomplish the task of hiding the first embossed pattern without changing it (claim 8).
[0011]
The "thinness" of a metal sheet is based on the fact that the present inventors deal with sheet-like materials or the concept of thin sheet-like metal ("Blech" (metal sheet) in German) is actually a thin metal sheet. Meaning is enough to show that there is. Although a thinner metal plate has been produced, the thickness of the type used for the juice body does not exceed 0.3 mm (claim 15). The metal thickness could be found with respect to the penetration of the initial imprint. Only if the image appears on the back side is the material considered "thin" and a second operation is required to obscure it.
[0012]
The change in surface due to the use of a protective layer, such as paint, is not actually an altered surface. The outer layer can be considered to be bonded to the surface, but can be removed. However, the deformation of the surface created by pressure constitutes a direct intrusion into the surface that cannot be removed from metal plates or other materials such as PET or plastic.
[0013]
The direction of deformation includes another advantage for imprinting using normal pressure to change the surface. This is because it is possible to easily engrave when finishing the body or the lid. Lateral movement can be applied directly, but such movement is not required.
[0014]
The present invention provides a reliably readable symbol obscured in the finished product. For example, the advantage of embossing this symbol is that it was possible for printed symbols, but it cannot be removed. The imprinted symbol always leaves a mirror image on the recognizable surface of the metal plate, but it can be scrambled, thereby ensuring that the symbol is completely obscured. A rough surface is imprinted across the image, completely covering (hidden) it and making it almost illegible.
[0015]
One way to make a "scramble" stamp is to use electrical discharge machining. This will extend to the back of the first embossing (pattern). As a second surface change on the opposite side of the first inscription, it is also possible to apply the electric discharge machining directly to the image on the back surface (claim 14). This treatment is comparable to treatment with abrasive paper corresponding to pressure deformation to penetrate the surface, or equivalent to electrical discharge machining to remove surface particles; this constitutes a surface penetrating change. In some cases.
[0016]
Experimental examples show that a penetration of 1/100 to 2/100 mm can be obtained with the correct metal thickness of the lid and the tab loop. Penetration is reasonably large on the first stamped surface, whether or not embossing is performed by pressing, scratching, engraving or cutting. This depth ranges from 4/100 to 5/100 mm.
[0017]
Compared to the reflectance of a smooth, high quality surface, the recognizability of the symbol impairs the reflection of light in rough parts of the surface, without having to emboss the image of the symbol.
[0018]
The invention is further described by means of the schematic representations of the examples.
[0019]
In each drawing,
FIG. 1 shows a partial perspective view of the upper part of a beverage can, for example, having a trigger tab with a loop-shaped handle;
Figure 2 shows a close-up view of the upper part of the grip end in a loop-shaped handle that can be used for the trigger tab;
FIG. 3 shows the cutout of FIG. 2 on the back side;
FIG. 4 is an enlarged view of a main part in FIG. 3 after covering the image of the symbol with the second engraving by the operation of the present invention;
4a and 4b are cross-sectional views in FIG. 4 illustrating the change of the surface after the first stamp and the second stamp;
FIG. 5 schematically illustrates various possible alternative means of imprinting in the second process, as opposed to any image, on the reverse side of the schematically illustrated stamp 20. Yes;
6, 7, and 8 show cross sections of actual metal parts.
[0020]
The container shown in FIG. 1 is made of a thin sheet of metal, and is closed with a lid 3 made of a thin metal plate. The latter appears at the seams in the area of the tabs 3a of the lid and can be opened by at least partially causing the tabs end to end. In order to initiate and advance the raising opening, the rivet 4 forms a loop 5 which is fixed near one end of the lid tab 3a. It is possible to raise, raise and push the grip 6 at the other end into the opening.
[0021]
The extension of one end of the grip 6 of the grip loop 5 (see FIG. 1) is shown in FIG. 2, as seen from below. Thus, this part is visible from the surface 6a, ie the end of the gripping loop, from below. The embossing symbol was imprinted on the surface near the end of the grip. In this case, a code representing a number was engraved or scratched on a surface containing three independent systems 7a, 7b and 7c arranged in an area 3a '.
[0022]
Since the sheet metal used is extremely thin, it is inevitable to form a tab image 8 (see FIG. 2) by engraving the code 7 on the back surface. In this case, the figures 8a, 8b and 8c can be found in the area 3a 'and thus appear on the upper side 6b according to FIG. It obscures the code 7 embossed in the grip loop, i.e. underneath the grip area 6, but these can be decrypted directly from the outside, as shown in FIG.
[0023]
FIG. 4 shows that this image was covered by a second imprint by weaving, patterning or hatching of oblique parallel lines. The recognizable outside 6b at the grip end 6 of the grip loop is again shown. Corresponding to the lower position of the grip portion on which the code 7 is embossed, the upper side is woven by the second engraving 10 as shown by 10 'in FIG. In this case, weaving is a simple (thin) hatching process.
[0024]
The next (second) inscription is made using a specially structured (specific patterned) stamp 10 'that shows the corresponding pattern on the surface of the woven location.
[0025]
The weaving changes the surface without applying a protective layer to the surface. No paint or other coating is placed on the image 8, but alters the weave in the surface itself (structuring, hatching, or other penetrating shaping process), thereby shaving or other Make removal by method impossible. The change due to this weaving is limited to the area where the image 8 of the previous marking 7 is found, for example, in the regularly delineated area 10 'shown in FIG. This area is located in the reinforced edge 6c (eg the new edge of the sheet metal loop), including the grip end (part 6).
[0026]
Regarding the description of the surface change, in FIG. The right half of the image shows that the first imprint 7 has been applied and that a clear image 8a ', 8a "has been formed on the back side, i.e. the outer side 6b. The image on the left half in FIG. 3) corresponds to that of Fig. 3. Here we have a weave in the form of a structure 11 (further described in Fig. 5). to). shows the penetration t ₁₁ to the surface.
[0027]
The first engraved 7a ', penetration depth t ₇ of 7a "is clear. Changing the cross-sectional structure of the sheet metal, and pressing the image on the opposite side. It is also possible highlight the image, or The altered internal structure allows the image to be recognizable through the otherwise smooth surface to cover or obscure the recognizable image 8a ', 8a "corresponding to 8a in FIG. , Requires a second surface change on the image side. This is set firmly on the surface, thereby changing the connectivity, smoothness or quality of the surface in the sense that directly induced surface changes cause irregularities in the relevant areas. Penetration depth t ₁₁ described above with reference to mask the image is essentially t ₇ smaller.
[0028]
The ratio between the two penetrations is such that the stronger initial inscription 11 on the 6b side is still recognizable on the 6a side. However, since it is covered by the weaving 11, the images 8a ′ and 8a ″ formed in advance cannot be recognized any more.
[0029]
The second surface change is not only lower in depth but also more focused on the surface compared to the first change. The first inscription is more strongly localized, making the symbol identifiable. The second change is limited to the surface to obscure the symbol. However, both of these have an immediate and direct effect on the surface, whereby they are permanently fixed and associated with the area in question. The symbol is clear when viewed from one side (6a), but is covered when viewed from the opposite side (6b). The present inventors are primarily concerned with sheet-like metal parts, but are also applicable to other materials, such as plastics or other substances capable of taking new forms to the surface structure. The concept of engraving can also be applied to appropriate processing by remembering the operations for the first and second penetrating introduction.
[0030]
The weaving (structuring or hatching) can be formed in a different way than that shown in FIG. Some examples of the stamp surface of the stamp 20 are shown in FIG. At 11, the saw-like woven pattern is embossed. In section 12, a weave pattern consisting of a very small cross-shaped firmly filled inscription is shown. At 13, the cross hatching is shown, which appears opposite after the second imprint. When all the weaves in FIG. 5 are drawn in a combined form and applied, the surface structure on the 6b side is changed so as to cover the entire area 10 ″. The range of the boundary 10 ″ is three types of images 8a, It is calculated to include 8b and 8c, and to form a regular boundary (boundary) already close to the quadrilateral containing boundary 10 ', as described in FIG.
[0031]
As shown in FIGS. 2 to 4, instead of placing a code and a second engraving on the grip loop area 3a ', the lid tab 3a can also have a corresponding embossed code. However, in this case, it is also necessary to weave or hatch a suitable area on the outside of the lid with a second stamp.
[0032]
This process is applicable to any area that is intended to obscure a code or symbol imprinted on a thin surface area.
[0033]
FIG. 6 shows an example of the ciphers 7, 7 ′, 7 ″ on the side visible to the naked eye (recognition side). The images 8, 8 ′, 8 ″ are seen in FIG. In FIG. 8, the present inventors show an example of a circular weaving inscription 11 (similar to the pattern in FIG. 5), but have not engraved the lower encryption number 8 yet.
[0034]
The combination of FIG. 7 and FIG. 8 results in an “encrypted” stamp. The weave 11 is formed in a limited outer area 10 "" extending over the maximum width of the code 7, 7 ', 7 ". The boundaries are regular and different from the shape of the seven engraved lines arranged in a circle.
[Brief description of the drawings]
FIG.
FIG. 1 shows a partial perspective view of the upper part of a can for drinking, for example, having a trigger tab with a loop-shaped handle.
FIG. 2
FIG. 2 shows an enlarged view of the upper part of the grip end in a loop-shaped handle that can be used for a raised tab.
FIG. 3
FIG. 3 shows the cutout of FIG. 2 on the back.
FIG. 4
FIG. 4 is an enlarged view of a main part in FIG. 3 after the symbol image is covered by the second engraving by the operation of the present invention.
FIG. 4a
FIG. 4a is a cross-sectional view in FIG. 4 illustrating the change of the surface after the first and second stamps.
FIG. 4b
FIG. 4b is a cross-sectional view in FIG. 4 illustrating the change of the surface after the first stamp and the second stamp.
FIG. 5
FIG. 5 schematically illustrates various possible alternative means of engraving in the second process, as opposed to any image, on the reverse side of the schematically illustrated stamp 20. is there.
FIG. 6
FIG. 6 shows a cross section of an actual metal part.
FIG. 7
FIG. 7 shows a cross section of an actual metal part.
FIG. 8
FIG. 8 shows a cross section of an actual metal part.

Claims (18)

A method of imparting a hidden symbol on a thin metal plate, preferably a beverage can,
A recognizable and easy-to-read symbol (7) is applied to one side (6a) of the sheet metal by embossing,
Next, engraving (10, 11, 12, 13) is performed on the back surface of the metal plate provided with the above-mentioned symbol, thereby maintaining the recognizability and readability of the engraving symbol (7) on one side. A method characterized in that the mirror image (8) appearing on the back side is covered by the next engraving (10), in particular, it is blurred. 2. The method according to claim 1, wherein the back side of the image (8) according to the first inscription (7) is then covered after the first inscription by weaving or by a second inscription by hatching. The first inscription on the inside of the tab (3a) of the lid (3) is such that the corresponding area of the tab of the lid is covered or indecipherable by the inscription (10) from outside the lid. Item 3. The method according to Item 1 or 2. The image by the first inscription (7) on the underside of the grip (6a) of the grip loop (5) made of thin sheet metal for raising the tab (3) is on the outside (6b) of the grip area (6). The method according to claim 1 or 2, wherein the method is covered by a second inscription. When the sheet metal is thinned, so that the image (8a, 8b, 8c; 8) recognizable from the back by the first inscription (7a, 7b, 7c; 7) does not emboss or emboss it The method of claim 1, wherein the method is also formed. The second imprint changes the surface of the confined area (10 ', 10 ", 10"') so that it can be compared to the portion adjacent to the image (8) which is not affected by the first imprint. 2. The method of claim 1, wherein the method reduces surface smoothness or quality. 2. The method according to claim 1, wherein the first imprint forms a symbol (7a, 7 ', 7a') which engraves, scratches or otherwise penetrates the surface. The surface of the more strongly localized area (7a ', 7a ") is initially placed on the surface of the more strongly localized area (7a', 7a") as compared to the next inscription on the backside (6b), which extends wider (10 ') and reduces the depth of the surface. 8. The method according to claim 1 or 7, wherein the inscription penetrates more clearly and changes the surface. 2. The method according to claim 1, wherein a point pattern (11) is formed in a limited portion (10 "") of the rear surface by the subsequent engraving. A thin sheet metal part of the can (1), such as a torso, bottom, lid (2) or flip tab (5) for attachment to the flip lid (2);
(I) embossing the recognizable and legible symbol or the same (7) on the inner surface (6a) by means of an initial marking, in particular notching,
(Ii) the first engraved image (8, 8 ', 8 ") appearing on the outer surface (6b) is covered by a surface imprint (10; 11; 12; 13), making it at least substantially difficult to read. And a thin sheet metal part. 11. A part (2) or grip loop (5) for a sheet metal can according to claim 10, in particular a thin sheet-shaped material part, wherein the inner symbols (7, 7 ', 7) are obscured. )), Characterized in that the outer image (8) is covered with the next inscription by means of weaving, patterning or hatching in the sense of an operation to change the structure of the surface (10; 11; 12; 13). Part of a thin sheet of material. The metal plate part according to claim 10, wherein the difficulty in reading the sheet-shaped metal part means that the metal part cannot be actually read. The metal plate part according to claim 10 or 11, wherein the sheet-shaped metal part is a part of a beverage can. A method of providing a hidden symbol on a sheet-like metal surface of a surface, especially a can for liquids (drinks) suitable for drinking,
A recognizable symbol (7) is produced, at least in a limited part of the surface, by forcing a first indentation on one side (6a) firmly;
A second weak penetration inscription is made on the back side (6b), whereby the front side (10; 11; 12; 13) is
Recognition of the symbol (7) created by the first engraving on one side is retained,
The image (8) formed by the first imprint on the back side is obscured and essentially illegible by the second imprint (10; 11l; 12);
The method characterized by varying the degree. The method according to claim 1, wherein the thickness of the sheet metal is less than 0.3 mm. A portion of a metal plate obtained by the method according to claim 1. In the thin metal part (3a ') of the grip (6), a trigger loop (5) is formed, which is fixed on at least three sides by a shaping edge (6c), so that the first and second markings are made on each surface. The metal plate part according to claim 10, 11 or 16, which is provided on the opposite side. The penetration degree by the first marking is higher than the penetration degree by the second marking on the back surface, that is, the penetration degree (t ₁₁ ) by the second marking is less than the penetration degree (t ₇ ) by the first marking. 15. The method according to 1 or 14.