FR2693963A1 - Prodn. of reflective plates, e.g. motor vehicle registration plates - Google Patents

Abstract

A rough support plate (17) is formed by cutting to approximate dimensions, with a recess for receiving a second surface plate (45). The surface plate is cut to dimensions slightly smaller than the support plate, and inserted into the recess of the support plate before application of numbers etc. to its surface. The plates are assembled on a double conveyor line.A first line has a supply (7) of rolled aluminium sheet, which is cut and stamped to form the support plates, and a storage magazine (11) for the half-finished plates. A second line has a supply of aluminium (39) and reflective coating material (37), a cutting head (45) and storage magazine (47). An automatic handling device (49) removes the surface plates from the magazine and places them into the recesses of support plates on the other conveyor.

Description

 Method and device for the production of mineralogical plates, in particular reflecting.

 The invention relates to a method and a device for the manufacture of number plates for the registration of motor vehicles in particular.

It relates in particular to mineralogical plates of the so-called double-reflectorized type or not.

 License plates, known as double plates, with a black background and white or aluminum characters are well known. These plates are obtained by assembling in a semi-cutting operation a thick aluminum support plate and a thin surface plate also in aluminum and bearing the background color. Character formation is carried out later by the mechanics. The semi-cutting operation is carried out using a cutting press, the two support and surface plates, pre-cut to the dimensions of the plate to be produced, being positioned manually on the press tool and assembled successively at a rate of 300 to 400. fi pieces per hour.

 For the manufacture of reflectorized plates, this manufacturing process can be used, the thin black surface plate being replaced by a plate coated with a reflective film. However, such a method has many drawbacks.

 First of all, the semi-cutting operation requires the use of a relatively thick support plate, about 1.2 mm thick since the material repelation must not exceed half the thickness. thick plate, i.e. 0.6 mm, which is barely sufficient depth for embedding the thin surface plate. In addition, embedding the peripheral edge of the thin plate within the support plate is poorly ensured by the fact that this thin plate is interposed between the die and the punch of the press, so that its internal edge s 'refines and rounds out with prejudice on the mounting connection of the plates.

 Then, the semi-cutting operation by the press effect and stretching on the thin plate produces an elongation of the latter, which results in a deformation of the surface flatness and therefore a bending of the latter. on the support plate, and by the formation of waves between the characters formed subsequently.

 In addition, the compulsory use of a thin plate with the same dimension as the support plate for the semi-cutting operation leads to a significant loss of material, of the order of approximately 12%. This drawback is accentuated by the fact that the reflective product is relatively expensive.

 Furthermore, the reflective product of the film coating the thin surface plate being essentially constituted by microscopic glass beads, the press tool is subject to rapid wear. The cost of resharpening semi-cutting tools is relatively high.

 Finally, the production rate is limited by the manual positioning of the plates before semi-cutting.

 The invention aims to remedy these drawbacks by proposing a new method of manufacturing type license plates with double plates and in particular reflectorized.

The process for manufacturing license plates according to the invention is in fact characterized in that it involves the following steps
- the manufacture of raw support plates, cut and formed to the dimensions of the plate to be produced, with an appropriate housing to receive a thin surface plate on which the characters of the plate to be produced will be formed in a conventional manner
the manufacture of said thin surface plates cut to dimensions slightly smaller than those of said housing formed on the support plate, and
- The assembly of said second thin surface plate and the support plate, in its housing, so as to constitute a plate ready to be numbered before installation on the vehicle.

 According to an important characteristic of the invention, the housing of the support plate comes from direct stamping of the plate, the peripheral edge being turned inwards over its entire length. The thin surface plate is engaged elastically in this housing, for example by bending its surface, then resuming its flatness in engagement under the retracted edges of the support plate. The thin surface plate is shaped to a dimension slightly smaller than its housing so that it can have a clearance allowing it to be slightly deformed, in particular during subsequent numbering.

This play space in particular eliminates any possibility of unsightly bending of this surface plate.

 Said edge of the housing is advantageously formed with a regular dovetail section so as to allow perfect embedding of the surface plate in the housing of the support plate, which can be entered into the assembly with a slight bending in this one.

 Furthermore, this edge contributes to improving the aesthetics of the plate by a framing effect of the surface plate.

 All of the aforementioned operations can be carried out according to a continuous process including two production lines, namely a first production line for the support plates, comprising a station for feeding rolls of aluminum strip to the thickness and width of the plates to be produced, this strip being stamped with its housing, then cut into raw support plates to the size of the plates to be produced, which are then stored by stacking in a storage station for the support plates at the end of the line , and a second line for manufacturing thin surface plates, comprising a station for feeding rolls of an aluminum strip coated or not with a reflective layer on the surface, this strip of width slightly less than that of the housing formed on the support plate being cut into thin surface plates, to a length slightly less than that of said housing of the support plate, which they are then stored by stacking at the end of this second line, these two lines being brought together into one by a station for assembling the thin plate on the support plate, this station essentially consisting of an automatic handling tool taking successively a thin plate of a stack at the end of the second line and depositing it precisely opposite the housing of the support plate conveyed on the junction line and applying it in its housing, the plates thus assembled being stacked at the end of the line .

 According to this arrangement, we no longer use a semi-cutting tool with a peripheral conformation as in the conventional process for making current double plates, but conventional stamping and notching tools for forming and cutting to length. support plates and single-blade tools for cutting thin plates from their supply strip. This type of tool is much less expensive than the aforementioned semi-cutting tools.

 Furthermore, in such a process, the production rate is no longer limited by the manual positioning of the plates before assembly of the current conventional process and can be notably increased in accordance with current automatic handling tools allowing assembly in continuous thin plates and support plates on a conveyor line.

 The invention also relates to a device for implementing the method defined above and the plates obtained.

An exemplary embodiment of the invention will be described below with reference to the accompanying drawings in which:
- Figure 1 is a schematic view of a channel for manufacturing license plates according to the method of the invention
- Figure 2 is a partial enlarged section of the plate obtained
FIG. 3 is a diagrammatic view of the tool used for forming the support plate, and
- Figure 4 is a more complete view of the assembly station.

 An example of an embodiment according to the invention is shown in FIG. 1, in a complete production line for license plates operating continuously. This chain has two lines, respectively 1 and 3, for the manufacture of the support plate and of the thin surface plate of the license plates produced, these two lines joining in a single 5 at the plate assembly station. -support and surface plate. The first line 1, corresponding to the manufacture of the support plates, and successively comprises a feed station 7, a forming station 8, a cutting station 9 and a storage station II of the support plates produced. supply 7 comprises a material coil 13 from which is unwound an aluminum strip 15, of about 7/10 mm and of width equal to that of the plates to be produced. This strip passes in front of the forming station 8 or the stamping of a hollow housing with the edge drawn inwards, then in front of the cutting station 9, where it is cut into plates 17 to the length of the plates to be produced by a classic end notching tool.

 At the stamping or forming station, the strip is stopped at a precise position with regard to the tool, while the stamping operation is carried out.

The press tool 19 (FIG. 3) consists of a lower die 21, the internal shape of which is flat bottom and with regular upper edges tucked inwards. These edges have a rounded upper protruding section. The shape of the matrix corresponds to the housing 22 (FIG. 2) of the surface plate to be formed on the support plate. It is rectangular. The punch 23 has a shape complementary to the die. It consists of four parts 25 which move laterally at the end of the press operation under the push of an axial drive rod 27, the end of which has a trapezoidal shape in section and acts as a wedge on the parts of the punch to push them outwards at the end of the operation. The lower die 21 is also formed by four pieces 29 in rocking each on an axis 31 which allows them to tilt laterally inwards at the end of the stroke. press, in addition to the punch. When the press rises, the punch closes and the die moves away, thus releasing the formed support plate. The edge of the deep-drawn housing is in the shape of a dovetail (Figure 2). The cut support plates 17 thus formed are conveyed on a conventional conveyor belt to the storage station 11 where they are stacked.

 The second line 3 disposed adjacent to the first, corresponds to the manufacture of the surface plates, intended to be assembled in the housing 22 previously defined of the support plate. This line comprises, at the inlet, the supply coils 33, 35 respectively of the surface reflecting adhesive film 37 and the aluminum strip 39 at the lower level, unwound to meet on pressure rollers 41 where the film is applied to the band. The aluminum strip has a width slightly less than that of the housing 22 formed on the support plate and its thickness is approximately 2/10 mm or less. The strip thus coated is drawn to a cutting station 43 with a straight blade, where the strip is cut into plates 45 of length slightly shorter than that of the housing of the support plate. The plates are then conveyed to a storage station. 47 where they are stacked. At the end of this line, and at a short distance from the previous conveying line, a handling tool 49 automatically picks up the surface plates 45 one by one, either on a small conveying element 51, or directly on the last storage station. 47, by means of a rotary arm 53 provided with a sampling plate 55 (FIG. 4), which has a curved lower surface 57 and is connected to a suction device with suction cups (not shown), so as to bend slightly the surface plate 45 upon removal and allow its insertion into the housing 22 of the support plate, when it is applied to the latter at a predetermined stop position. Due to the bending, the dimensions of the plate are slightly reduced, which allows it to be lowered with a small clearance in the housing of the support plate. At assembly, the suction is released and the surface plate returns to its original flat shape, being retained recessed with little play on the retracted edges 59 of its housing (FIG. 2).

 The plates 61 thus obtained are then sent to a storage station 63 where they are stacked, ready for subsequent numbering.

 The above clearly demonstrates the stated advantages of the invention, namely the optimization of the thickness of the support plate reduced to a minimum value of 0.7 mm instead of 1.2 mm, the increase in its rigidity by the stiffening ribbing effect on the edges formed despite the reduction in thickness, the improvement of the aesthetics of the plate by the framing effect of the surface plate, good positioning of the plate fine surface in its housing, perfectly trapped but free from a slight expansion for numbering, the use of conventional tools and of low wear unlike the peripheral semi-cutting tools on the reflective material, the absence of fall of material on the thin plate and in particular in reflective product (gain of about 12%) and finally an increase in the rate of production, unlimited and constrained (problem of falls which do not come loose) to a manual positioning as in the current current process (3000 instead of 400).

Claims (7)

 1. A method of manufacturing number plates, in particular of plates of the so-called double plate type, reflectorized or not, characterized in that it involves the following steps  - the manufacture of raw support plates (17), cut and formed to the dimensions of the plate (61) to be produced, with an appropriate housing (22) to receive a thin surface plate (45) on which will be formed in a conventional manner the characters of the plate to be produced;  the manufacture of said thin surface plates (45) cut to dimensions slightly smaller than those of said housing (22) formed on the support plate, and  - The assembly of said second thin surface plate and the support plate, in its housing (22), so as to constitute a plate (61) ready to be numbered before installation on the vehicle.  2. A method of manufacturing number plates according to claim 1, characterized in that it operates continuously, including two production lines, namely a first line for manufacturing the support plates (1), comprising a supply station ( 7) in rolls of an aluminum strip (15) to the thickness and width of the plates to be produced, this strip being stamped with a hollow housing (22) with edge drawn inwards (59) capable of accommodating said second surface plate (45) with a slight clearance on its edge, then cut into support plates (17) to the length of the plates to be produced, which are then stacked in a storage station (11) of the support plates end of line, and a second production line (3) of thin surface plates, comprising a roll feeding station (33, 35) of an aluminum strip (39) coated or not with a reflective layer (37) on the surface, this strip of width slightly less smaller than that of the housing (22) formed on the support plate being cut into thin surface plates (45), to a length slightly less than that of said housing (22) of the support plate, which are then stored by stacking at the end of this second line, the two previous lines being combined into a single (5) by a station for assembling the thin plate on the support plate, this station essentially consisting of an automatic handling tool (49) successively picking up a thin plate of a stack at the end of the second line and depositing it precisely opposite the housing (22) of the support plate conveyed on the junction line (5) and applying it in its housing, the plates thus assembled (61) being stacked in the end.  3. Device for implementing the method defined in claim 1 or 2, characterized in that it comprises two production lines, namely a first line for manufacturing the support plates (1), comprising a supply station (7) in rolls of an aluminum strip (screw) to the thickness and width of the plates to be produced, this strip being stamped with a hollow recess (22) with edge drawn inwards (59) suitable for accommodate said second surface plate with a small clearance on its edge then cut into support plates to the length of the plates to be produced, which are then stacked in a storage station (îî) of the support plates at the end of the line, and a second line for manufacturing (3) thin surface plates, comprising a roll feeding station (33, 35) of an aluminum strip (39) coated or not with a reflective layer (37) on the surface, this strip slightly less width than the logeme nt (22) formed on the support plate being cut into thin surface plates (45), at a length slightly less than that of said housing of the support plate, which are stored by stacking at the end of this second line, the two lines previous being collected in a single (5) by a station for assembling the thin plate on the support plate, this station essentially consisting of an automatic handling tool (49) successively picking up a thin plate (45) of a stack at the end of the second line and depositing it precisely opposite the housing (22) of the support plate conveyed on the junction line (5) and applying it in its housing, the plates thus assembled (61) being stacked in end of line.  4. Device according to claim 3, characterized in that the supply of the second line (3) consists of a roll or coil (35) of an aluminum strip (39) of small thickness and slightly less width to that of the housing (22) formed on the support plate, and by a roll (33) of reflective adhesive film (37) of the same width as the aluminum strip and applied to the latter by pressure rollers (41).  5. Device according to claim 3 or 4, characterized in that the forming or stamping tool (19) on the line of the support plates comprises a rectangular lower matrix (21) with a flat bottom and regular edges returned towards the inside the upper level and an upper movable punch (23) of complementary section to that of the die and consisting of four parts (25) which move apart at the end of the operation under the push of an axial drive rod (27) whose end has a section shaped to act as a wedge on said parts of the punch and push them laterally against the die profile so that the forming resulting from the edge (59) of the housing is dovetailed, the matrix also being formed by four parts (29) each rocking on an axis (31), which can close laterally under the thrust at the end of the operation and which are released when the press is withdrawn.  6. Device according to one of claims 3 to 5, characterized in that the automatic handling tool (49) comprises a sampling plate (55) with concave curved lower surface (57) connected to a suction device at suction cups. allowing the assembly of the surface plate (45) in curved formation in the housing (22) of the support plate, this plate once released returning to its natural plane formation retained embedded with very little play by the retracted edges (59 ) of the accommodation.  7. license plate obtained by the implementation of the method and device defined in the preceding claims, characterized in that it is of the double plate type, comprising a thick support plate (17) and a thin surface plate (45) , the surface plate being inserted into a housing (22) formed on the support plate, retained in the latter by its edges (59) with profile retracted inwards.