EP0754569B1 - Method and embossing tool for manufacturing embossed plates, in particular motor vehicle licence plates - Google Patents

Abstract

The distance between the facing work surface parts (6',7') of the top (1) and bottom part (2), when the embossing die is closed at the end of the embossing process, is smaller in the area of the raised parts (22) of the plate (20) than the distance between the facing work surfaces (6,7) in the area of the recessed parts (21). In the top part, the recess (3) for each character being embossed is surrounded by a rim (5) ending a cutting edge and protruding towards the bottom part. The depth (t) of the recess for embossing a character in the top part, compared with the protruding rim is less than the height (h) of the corresponding protuberance (4) on the bottom part for embossing the same character.

Description

The invention relates to a method and an embossing tool for the production of embossed signs, in particular motor vehicle license plates, where one, if necessary provided on one side with a reflective film Sheet metal, in particular aluminum sheet, by means of a Embossing tool consisting of several upper parts and lower parts to a shield with raised protrusions on one side of the shield Sections and intermediate deepened sections embossed and the raised sections using on the visible side of the shield a colored plastic film can be made colored.

According to the prior art, signs, in particular Motor vehicle license plates, first in one out an upper tool part and a lower tool part Embossing tool, the letter and / or Combination of numbers, also called legend, sublime be embossed on the visible side of the sign. In in a second step, the raised is embossed Legend and possibly also the edge colored. With a license plate, the legend of the white Shield colored black. This is done e.g. according to DE 37 41 232 C2 using a so-called hot stamping plastic film. In this process, the Plastic film as a carrier material for a heat-removable Colour. The embossed sign is placed on a work table or put a conveyor belt so that the visible side is directed upwards. It will over the plastic film the shield tensioned and then shield and Slide the film together under a heated pressure roller. Under the heat of the pressure roller, the Color pressed onto the raised sections of the shield and is then permanently with the sublime after cooling Sections of the shield, i.e. the letters and / or Numbers connected. After cooling, the plastic film subtracted from the shield, with only the the raised portions of the shield are heat sealed Detach color areas from the film, but otherwise the color sticks to the film. Such However, the machine for heat sealing the plastic film is with over DM 10,000, are relatively expensive and also Always two steps to produce the sign required. Furthermore, heat sealing is also possible with one correspondingly high power consumption because the pressure roller shortly to a correspondingly high temperature must be brought.

Before the heat seal system was introduced, it was done the application of a solvent-based paint a so-called rolling machine. Apart from that for reasons of environmental protection and other dangers solvent-based paints can no longer be used rolling also required an additional one Operation and the rolling machine had to be carefully cleaned after use.

The invention is therefore based on the object of a method and also a tool for making embossed Signs, in particular motor vehicle license plates, of the type mentioned at the beginning to show which the manufacture of the finished sign with a enable as little work and energy as possible.

This is achieved according to the invention in that a Plastic film is used, the one-sided with a pressure sensitive adhesive is provided that the plastic film before embossing the label with its adhesive side side to the later visible side of the unembossed, flat board, and that when embossing in one single operation only in the area of the sublime Sections a higher glue to glue Pressure is applied while on the recessed sections little or no, not the glue Sticky pressure is exerted.

A stamping tool for carrying out the method is according to the invention characterized in that the upper and lower parts of the embossing tool each other facing first working areas for embossing the raised sections of the Schildes and facing each other, second working areas for embossing the have recessed portions of the shield and that a mutual distance of the first work area areas with the embossing tool closed at the end of the Embossing process is smaller than a mutual distance between the second Worktop areas.

The basic idea of the invention is therefore a plastic film to use one-sided with a pressure sensitive Glue is provided, and this film together with the board, which may already have a pre-made, can have an embossed and colored edge (cf. DE 40 40 386 C1) in the embossing tool. While of embossing, in the upper and lower part of the Embossing tool are pressed onto the board and the raised sections are formed also the plastic film in the area of the raised sections under correspondingly high pressure on them Sections pressed. Because of this high pressure the pressure sensitive adhesive is glued, i.e. made adhesive. Due to the adhesive effect of the adhesive is now either depending on the type of plastic film used the colored plastic film itself or a color layer applied on one side to the film which is the adhesive layer on the raised Sections glued. In the area of the wells of the Sign, on the other hand, does not stick to it because there little or no pressure on the plastic film is exercised so that the pressure sensitive in these areas Glue is not made adhesive. In In the former case, the embossing tool should be designed in this way be that the plastic film on the border between the raised sections and the recessed sections severed and after opening the embossing tool the rest of the black plastic film like a grid can be deducted. In the latter case, the slide not severed. When the film is removed, it comes off just the color where it touches the raised sections the label was stuck on, from the foil, which in this case only serves as a carrier for the color. Since in both cases the embossing and coloring of the Sign is done in one operation, is essential saved on working hours and it is also not a separate one Heat sealing machine required. As well no rolling machine is necessary and that with such rolling machines and solvent-based Disadvantages associated with colors are avoided.

When performing the procedure, it is useful a plastic film used, the glue at accordingly high pressure becomes sticky at room temperature. This has the advantage that embossing tools are not heated must therefore be easy to manufacture and also a low energy expenditure is necessary.

Furthermore, it is useful when carrying out the method a colored one, e.g. black, plastic film used a pressure sensitive adhesive layer on one side Has adhesive.

However, a plastic film could also be used the one side with a removable paint layer is, the layer of paint on the plastic film facing away from an adhesive layer of pressure sensitive Has adhesive.

Figur 1

einen Teilschnitt des geöffneten Prägewerkzeuges mit eingelegter Platine und eingelegter Kunsstofffolie,

Figur 2

einen Teilschnitt des Prägewerkzeuges am Ende des Prägevorganges.

The method according to the invention and an embossing tool for carrying out the method are explained in more detail below with reference to an embodiment shown in the drawing. Show it:

Figure 1

a partial section of the opened embossing tool with inserted circuit board and inserted plastic film,

Figure 2

a partial section of the stamping tool at the end of the stamping process.

The embossing tool consists of several upper parts 1 and several assigned sub-parts 2. For each character, i.e. every letter or number is for making of a motor vehicle license plate own upper part and a lower part provided.

The upper part 1 has a recess 3 corresponding to the Contour of the character to be embossed. The lower part 2 has a projection corresponding to the character to be embossed 4 on. The depression in the upper part 1 is appropriate surrounded by an edge 5 projecting towards the lower part, which corresponds exactly to the contour of the recess 3. This protruding edge 5 can advantageously in a cut edge leak as shown in the drawing. The Work surface 6 of the upper part 1, which is the recessed Sections 21 of the embossed plate 20 corresponds (see FIG. 2), is opposite the edge 5 of the lower part 2 staggered away. This means that the protruding edge 5 in relation to the work surface 6 protrudes an amount a of, for example, 0.3 mm. The depth t of the recess 3 compared to the above Edge 5 is e.g. 1.7 mm.

In contrast, the height h of the corresponding Embossed the same sign provided on the lower part Projection 4 greater than the aforementioned depth t. In the present example, the height h can be approximately 2-3 mm be.

This ensures that according to Figure 2 when closed Embossing tool at the end of the mutual embossing process Distance A1 of the working areas facing each other 6 ', 7' of upper part 1 and lower part 2 in the area of the raised portions 22 of the shield 20 is smaller than the mutual distance A2 of each other facing worktop areas 6, 7 in the area of recessed sections 21 of the finished plate 20. By this configuration is achieved that the plastic film 24, e.g. a colored black plastic film 24, in Area of the raised portions 22 of the shield 20 with high pressure is pressed on the visible side 20a, while in the region of the recessed sections 21 Pressure does not occur or only takes place with low pressure.

In Figure 1, 20 'denotes a flat board, e.g. consists of aluminum sheet. Possibly However, this board could also be made of sheet steel or Plastic. For the production of a motor vehicle license plate can this board on your Visible side 20a coated with a reflective film 23 be. The board 20 can not with one shown prefabricated edge to be provided has already been colored. The coloring can according to DE 40 40 386 C1 even before attaching the reflective film 23 take place. Above the visible side 20a of the circuit board 20 'also becomes a plastic film 24 arranged on its underside facing the visible side from the film manufacturer with an adhesive layer 25 is made of pressure sensitive adhesive. The glue is designed in such a way that it can only be used when high pressure becomes sticky and its adhesive effect unfolded.

If the embossing tool with inserted board 20 'and inserted plastic film 24 in a hydraulic press brought and the embossing process completed there, then take Upper part 1 and lower part 2 at the end of the embossing process position shown in Figure 2. Since the distance a1 in Area of the raised portion 22 of the shield 20 is smaller than the distance A2 in the recessed sections 21 of the shield 20, the slide will end of the embossing process in the raised section 22 high pressure pressed against this raised portion. Due to this high pressure, the adhesive layer 25 in adhesive area and thus the plastic film 24 glued to this in the raised area 22. In the deepened Area 21, however, the pressure is insufficient, to make the adhesive layer 25 sticky here. As a result, the recessed area 21 of the Shield 20 an adhesive of the film on the visible side 20a of the shield 20 or to the reflective film 23. The upper part 1 and the lower part 2 are made to register. By the above designed as a cutting bar Edge 5 becomes the plastic film 24 at the transition between the raised section 22 and the recessed section Section 21 severed. Upper part 1 and lower part 2 must be coordinated so that during the stamping process only stain the colored plastic film 24 is cut through. The underlying reflective Foil 23 must not be damaged so that the surface so affected that the exam according to DIN 74069 no longer exists. After opening of the embossing tool you can use the remaining black plastic film 24 pull off like a grid. Then remain nor the unembossed sections 21 and the legend that through those glued to the raised portions 22 black plastic film becomes visible.

Instead of a colored plastic film, you can also use a plastic film that is one-sided with a Color layer, e.g. a black layer of paint is. The color layer is then on the plastic film opposite side with an adhesive layer made of pressure sensitive adhesive, coated. In this case the plastic film only serves as a carrier film for the color layer. By in the area of the raised portions 22nd The resulting high pressure becomes the adhesive of the paint layer sticky in these areas and to the raised portions 22 of the shield glued. In the deepened sections 21 the shield, however, does not stick, so that one after opening the embossing tool, pull off the carrier film can. Then only those detach from the carrier film Sections of the color layer in the area of the raised Sections 22 adhered to them by the high pressure were.

Claims (8)

1. A method of manufacturing embossed plates, especially vehicle licence plates, in which a plate of sheet metal, especially of aluminium sheet, optionally provided on one side with a reflecting film, is embossed by means of an embossing tool consisting of a plurality of upper and lower parts into a plate with raised sections projecting on the face side of the plate and intervening recessed sections, and the raised sections on the face side of the plate are rendered coloured using a plastics film provided with colour, characterized in that the plastics film is provided on one side with a pressure-sensitive adhesive, in that the plastics film is applied before the embossing of the plate, with its adhesive side on the subsequently face side of the un-embossed, flat plate, and in that during the embossing a higher pressure causing the adhesive to bond is applied in a single working step only in the region of the raised sections, while no pressure or only a smaller pressure which does not cause the adhesive to bond is applied at the recessed sections.
2. A method according to claim 1, characterized in that the adhesive bonds under pressure at room temperature.
3. A method according to claim 1 or 2, characterized in that the plastics film is provided on one side with a releasable coloured layer, wherein the coloured layer has the adhesive layer of pressure-sensitive adhesive on its outer side facing away from the plastics film.
4. A method according to claim 1 or 2, characterized in that the plastics film is self-coloured.
5. An embossing tool for carrying out the method according to any of claims 1 to 3, characterized in that the upper parts (1) and lower parts (2) of the embossing tool comprise mutually facing first working surface regions (6', 7') for embossing the raised sections (22) of the plate (20) and mutually facing second working surface regions (6, 7) for embossing the recessed sections (21) of the plate (20), and in that a mutual spacing (A1) of the first working surface regions (6', 7') with the embossing tool closed at the end of the embossing operation is smaller that a mutual spacing (A2) of the second working surface regions (6, 7).
6. An embossing tool according to claim 5, characterized in that for each symbol to be embossed at least one depression (3) forming the respective first working surface region (6', 7') in each upper part (1) is surrounded by a rim (5) projecting towards the respective lower part (2), whereby the respective second working surface regions (6, 7) of the respective upper part, which are associated with the recessed sections (21) of the plate, are offset relative to the rim (5) away from the lower part (2).
7. An embossing tool according to claim 6, for implementing the method according to claim 4, characterized in that the projecting rim (5) tapers to a cutting edge.
8. An embossing tool according to claim 6 or 7, characterized in that the depth (t) relative to the projecting rim (5) of the depression (3) provided in the upper part (1) for embossing a symbol is smaller than the height (h) of a corresponding projection (4) provided on the lower part (2) for embossing the same symbol.

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