The invention relates primarily to a method for in-line producing insulating panels.

Plants are known to produce panels consisting of two outer sheets and an inner layer of insulation material, see e.g. WO 2010/029587. Although the production lines allow to manufacture very large panels (up to 25 m in length), often the area to be covered is so large that the panels have to form a tessellation. To ensure continuity of coverage between a panel and the adjacent one, one of the two sheets protrudes from the panel by a certain length, and this overhang is used to overlap the adjacent panel. See e.g. EP1371483 for general information. In order to make the panel with protruding sheet metal while maximally minimizing waste, two adjacent cut ends of sheet metal are overlapped in line and a strip is laid over them to join them. Then, in a press, foaming takes place between two continuous foils of sheet metal, one continuous and one with the joined sheets, and finally the sheets are cut and separated by tearing the strip. Thus, by separating the previously spliced ends, there result a panel end with protruding sheet metal and a panel end with sheet metal flush with the inner insulating layer.

To perform the above operations, the line comprises a station for cutting a metal sheet and a station for splicing two ends of sheet metal and laying the strip. The first station cuts portions of sheet metal that the downstream splicing station receives to overlap and splice them.

The disadvantage of the system is that the two stations must be physically separated by the maximum length of panel that can be produced. This results in a very large, bulky and expensive system.

Proposing an alternative production method is the primary object of the invention, which is defined in the appended claims, wherein the dependent claims define advantageous variants.

A method is proposed for in-line producing insulating panels of the type having two outer sheet metals made from a continuous foil of metal sheet and an insulating layer between them (e.g. rockwool or polyurethane foam), wherein a junction is created between the end of a trailing sheet metal belonging to a train of spliced sheet metals and the end of a continuous foil of metal sheet, the train of spliced sheet metals moves to advance down the line the last-made junction between sheet metals, the train of spliced sheet metals is cut at a point upstream of the last-made junction between sheet metals, the cycle is repeated.

Advantageously, the method is so flexible that it can be used to produce panels with or without said protruding portion. In the case the panels have said protruding portion, that is, the panels have a portion of protruding metal sheet which can be overlapped over another finished panel, said junction between the end of the trailing sheet and the end of the continuous foil comprises an overlap between the sheet metals.

The overlapping may be accomplished by placing the end of the trailing sheet metal under the end of the continuous foil or by placing the end of the trailing sheet metal over the end of the continuous foil.

According to a preferred embodiment, said junction takes place in a splicing station and the cutting of the train of spliced sheet metals takes place in a cutting station (e.g. by laser, rotary saw or waterjet), wherein the splicing station is downstream of the cutting station. This configuration ensures production efficiency and less displacement for the stations if they are movable.

According to a more preferred embodiment, said stations are movable back and forth along the advance direction of the train of sheet metals, to adjust to the speed of the line.

According to an even more preferred embodiment, said stations are movable back and forth along said direction of travel integrally with each other. Thus, it is possible to sequentially use only one position and control means for both. However, said stations may be independently movable forward and backward along said advance direction.

According to an even more preferred embodiment, while executing the cut, the cutting station moves along said advance direction with a speed equal to the advance speed of the sheet metal to be cut, then the splicing station moves backwards with respect to said advance direction to reach the tail of the train of spliced sheet metals and the freshly-cut end of the continuous foil, the splicing station, while moving along said advance direction with a speed equal to that of the train of spliced sheet metals, performs the splicing between the tail of the train of spliced sheet metals and the freshly-cut end of the continuous foil, the splicing station returns to the initial position.

According to a preferred embodiment, the train of spliced sheet metals advances along the line at a substantially constant speed to ensure repeatable machine times along the line and to avoid temporary in-line machine stops. According to a preferred embodiment, the relative distance between said stations is adjustable. This is very useful during prototyping or start-up of the plant, to find the most appropriate relative distance for the panel to be produced.

According to a preferred embodiment, said junction is created by deposition of a tape on the sheet metals.

According to a preferred embodiment, the cutting of the train of spliced sheet metals takes place along a direction perpendicular to the plane of the sheets and is directed so that the surface of the sheet metal corresponding to the outside of the finished panel, is cut first. In this way any residual burrs on the sheet after cutting do not scrape on the sheet after the panels have been detached. In particular said direction perpendicular to the plane of the sheets may be from top to bottom or from bottom to top.

According to a preferred embodiment, the train of sheet metals advances horizontally.

Another aspect of the invention is an aforementioned plant comprising machines for performing the method. In particular, a station is proposed for in-line production of insulating panels of the type having two outer sheets made from a continuous foil of metal and an insulating layer between them (e.g. rockwool or polyurethane foam), comprising a splicing machine for splicing the end of a trailing sheet metal belonging to a train of spliced sheet metals and the end of a continuous foil of metal sheet, means for moving the train of spliced sheet metals and advance along the line the last-executed junction between sheet metals, a cutting station to cut the train of spliced sheet metals at a point upstream of the last- executed junction between sheet metals,

In case the panels have the aforementioned protruding portion, the splicing machine is configured to splice the end of the trailing sheet metal and the end of the continuous foil with an overlap between the sheets (the overlap may be accomplished by placing the end of the trailing sheet metal below the end of the continuous foil or by placing the end of the trailing sheet metal over the end of the continuous foil).

According to a more preferred embodiment, said stations are mounted on linear guides to be movable back and forth along the advance direction of the train of sheet metals.

According to an even more preferred embodiment, said stations are movably mounted on a common platform which is movable back and forth along said advance direction.

According to an even more preferred embodiment, the stations are configured so that while it is cutting, the cutting station moves along said direction with a advance speed equal to the advance speed of the sheet metal to be cut, then the splicing station moves backwards with respect to said advance direction to reach the tail of the train of spliced sheet metals and the freshly-cut end of the continuous foil, the splicing station, while moving along said advance direction with a speed equal to that of the train of spliced sheet metals, executes the junction between the tail of the train of spliced sheet metals and the freshly-cut end of the continuous foil, and the splicing station returns to the initial position. According to a preferred embodiment, said stations are mounted so that their relative distance is adjustable.

According to a preferred embodiment, the splicing station comprises a strip dispenser for laying a strip on the sheet metals.

According to a preferred embodiment, the cutting station comprises a blade or saw movable along a direction perpendicular to the plane of the sheet metals. In particular, the blade is directed so as to first cut the surface of the sheet metal that corresponds to the outside of the finished panel.

The advantages of the invention will be clearer from the following description of a preferred embodiment of device and method, reference being made to the attached drawing wherein

- Figs. 1÷3 schematically show an operating sequence in a part of plant according to the invention;

- Figs. 4÷7 show in more detail an operating sequence in a part of plant according to the invention. Fig. 1 shows a line of plant MC with a roll 10 of metal sheet being unwound, for example, on a roller guide. After several processing cycles, as will become clearer below, there has formed in the line a train 20 of sheet metals 22 cut from the roll 10 and spliced one to the other by means of an overlap portion 24 and an adhesive tape (not shown). The train 20 (fig. 1) is advanced along the line (direction F) until the last-made portion of overlap 24 (indicated by 26), i.e. the one that is "at the tail" of the train 20 and is, with respect to the line, the closest to the roll 10, has covered a certain distance. To this distance there corresponds a segment of new sheet metal 14 unwound from the roll 10.

At this point (Fig. 2) the new sheet metal 14 is cut with a cut 16. This results in two free ends of sheet metal: one end belongs to the tail of the train 20 and one end belongs to the sheet metal 14.

These two ends (Fig. 3) are then overlapped and spliced by means of a new overlap portion 24, thereby lengthening the train 20 with a new sheet metal 22.

The cycle then restarts from Fig. 1 to add a new sheet metal 22 to the train 20. It is understood that the sheet metal unwound from the roll 10 during the step of Fig. 1 corresponds to the length of the panel to be produced plus the relative overlap portion.

The immediate advantage of this method is that the length of the panel to be produced does not dramatically affect the layout of the plant and its length. In particular, there is no need for a guide that is as long as a sheet metal cut from the roll 10 and that is placed between a cutting point and a splicing point of the sheet metal. In addition, the cutting point and the splicing point of the sheet metal no longer need to be as far apart as a sheet metal cut from the roll 10, which in the worst case corresponds to the maximum length of the panel to be produced (tens of meters!).

A variant illustrating the miniaturization of the plant is shown in Figures 4÷7. Fig. 4 shows a line of plant MC2 with a roll 10 of metal sheet being unwound, for example, on a roller guide. After several processing cycles, as explained above, a train 20 of sheet metals 22, cut from the roll 10 and spliced together one to the other via an overlap portion 24 and an adhesive tape (not shown), has formed in the line.

The splicing of the sheet metals takes place by means of a splicing station 40 and the cutting of the train of spliced sheet metals takes place by means of a cutting station 50, where the splicing station 40 is, with respect to the line, downstream of the cutting station 50.

The stations 40, 50 are integrally movable back and forth along the in-line advance direction F of the train 20. For example, the stations 40, 50 are mounted on linear guides and coupled to a common ball screw rotated by an electric motor controlled by a PLC. The rotation of the screw simultaneously translates the stations 40, 50 forward or backward on the line, relative to the sheet metal arriving from the roll 10 and relative to the train 20.

Preferably, the relative distance between the stations 40, 50 is adjustable.

To avoid temporary machine stops on the line, the train 20 of spliced sheet metals advances along the line at a substantially constant speed.

The processing cycle envisages these steps:

1) the cutting station 50 (fig. 4) performs the cut 16 of the metal sheet 14 arriving from the roll 10 and, to match the line speed, simultaneously moves along the advance direction F with the same speed as the sheet metal arriving from the roll 10; 2) the splicing station 40 (Fig. 5) moves backward with respect to the direction F to reach the tail of the train 20 and the freshly-cut end of the continuous foil 14;

3) the splicing station 40, while moving along the direction F, performs a new overlap 26 and a splice between the tail of the train 20 and the freshly-cut end of the continuous foil 14. E.g. said splice is created by depositing a tape on the sheet metals;

4) the splicing station 40 returns to its initial position, and with it also the station 50, to re-start the cycle.

Note that the cutting and splicing operations in Figures 1÷7 may also be performed by known means. In the figures the continuous displacement of the train 20 is appreciable, however the spatial location of the cutting point and/or the junction point may vary quantitatively from what is shown.

The relative position of the stations 40, 50 may be swapped by reversing the directions of their movements.