PLANT FOR PROCESSING SHEET-LIKE MATERIALS WITH AUTOMATIC MEANS FOR FEEDING/UNLOADING THE SHEETS

DESCRIPTION The present invention relates to a plant for feeding and unloading sheets to/from an operating machine such as a laser machine for processing sheet-like materials. It is known in the technical sector relating to the cutting, incision and/or hot-pressing of sheets made of paper, cardboard and the like, performed by means of laser-type machines, that there exists the dual need to:

- feed to said machines the sheets to be worked by means of suitable apparatus provided with hinged arms which remove the sheet from corresponding stacks provided in the vicinity of the machine; subject the fed sheets to the incision/cutting process envisaged; and

- extract from the machine the worked sheets in order to stack them in special storage zones from where the formed stack is then conveyed away for subsequent processing and packaging.

It is also known that in the particular application of processing sheet-like materials by laser machines this working sequence is performed in a discontinuous manner and with particularly long cycle idle times, owing to the need to position the sheets correctly opposite the laser emission apparatus which must be kept stably immobile so as not to lose the reference and directional settings which are essential for correct operation thereof.

The technical problem which is solved, therefore, is to provide a plant for processing sheet-like material by

means of a laser cutting/incision apparatus, which comprises apparatus for loading/unloading the sheets to/from means able to be reached by the laser beam for processing the said sheets, so as to enable a substantially continuous working cycle such that the machine stoppage idle time which is currently necessary with the apparatus of the known type is eliminated. In connection with this problem it is also required that this plant should have compact dimensions, be easy and inexpensive to produce and assemble and be able to be easily installed also in combination with already existing machines without the need for substantial modification thereof. These results are achieved according to the present invention by a plant for processing sheets by means of a laser apparatus comprising at least one sheet insertion/removal machine for loading/unloading the sheet and at least one device for containing and directing the sheet, arranged between said laser apparatus and said sheet insertion/removal machine and able to be operated so as to pass from a first rest position for feeding/extracting the sheet into a second working position able to bring the sheet into a position where it is exposed to the laser and vice versa.

Further details may be obtained from the following description of a non-limiting example of embodiment of the subject of the present invention provided with reference to the accompanying drawings in which: - Figure 1 shows a partial top plan view of the plant according to the present invention;

Figure 2 shows a schematic cross-section along a longitudinal vertical plane of the plant according to

Fig . 1 after cycle start-up ;

- Figure 3 shows a cross-section similar to that of Fig. 2 with the plant during feeding of the sheet;

- Figure 4 shows a cross-section similar to that of Fig. 2 with the plant during exposure of the sheet to the laser; and

- Figure 5 shows a cross-section similar to that of Fig. 2 with the plant during extraction of the sheet. As shown, the plant for processing a sheet-like material 1 according to the invention comprises essentially:

- a fixed laser apparatus 100;

- a sheet insertion/removal ^' machine 200 and

- a device 300 for containing and directing the sheet 1, arranged between the said apparatus and machine and able to be operated so as to pass from a first rest position for feeding/extracting the sheet into a second working position able to bring the sheet 1 into a favourable position for exposure to the laser beam. In greater detail the laser apparatus 100, which is of the conventional type and therefore not described more fully, comprises a laser emitter 110 connected to a support and positioning structure 120 able to be displaced on guides 122 in the transverse direction, for corresponding positioning thereof, and to rotate about an axis 121 for adjusting the inclination of the beam; the apparatus is associated with a gas storage cylinder 130 for powering the laser. The sheet insertion/removal machine 200 comprises a first drawer 211 for storing the sheets 1 to be processed and a second drawer 212 for storing the processed sheets; each drawer is associated with a corresponding pair of loading arms 230 and unloading

arms 240, respectively, which are arranged on opposite sides of the machine and connected together at their respective free ends by a corresponding internally hollow cross member 231,241 associated with suction means able to place it under a vacuum for retaining the sheet so as to pick up/release the sheet 1 before/after processing thereof.

The loading arms 230 rotate about a transverse shaft 231 which is joined to the body of the machine and at their free ends have an articulation 232 hinged on a second shaft 232a of the arm 230.

Similarly the unloading arms 240 are hinged on an associated transverse shaft 241 fixed to the machine and have an articulation 242 which is hinged on a second shaft 242a of the arm 240 arranged at the free end of the arms .

The machine envisages moreover independent drive means 250 for moving said arms 230,240. The device 300 for containing/exposing the sheet 1 to the laser 100 comprises in turn a container 310 inside which the sheet 1 is arranged; this container is associated with means (not shown) for centring the said sheet depending on the co-ordinates of the laser and movement means 320 comprising a hinged arm 321 which is connected to a gearmotor 322 able to cause a displacement of the said arm from a first retracted rest/unloading position (Fig. 3,-5) into a second extended working position (Fig. 4) . The plant envisages, moreover, means 1000 for powering, controlling and synchronizing the movements of the various movable parts, so as to ensure the correct working sequence without mutual interference . With this structure the operating sequence of the plant

is as follows :

- firstly the container 211 is filled with the sheets 1, the direction of the laser 110 is adjusted about the fixed axis 121, the corresponding co-ordinates are stored in the control devices 1000 and the container 310 is arranged in the rest position;

- then the loading arms 230 are moved so as to pick up a sheet 1 from the container 211 (Fig. 2) and rotate about their fixed axis 231; - the sheet 1 is deposited inside the container 310 (Fig. 3) ;

- the said sheet is centred inside the container and at the same time the arms 230 are operated so as to return into the initial position; - the gearmotor 322 is started so as to bring the arm 321 into the extended position (Fig. 4) such that the container 310 tilts into an inclined position able to bring the sheet 1 within the scanning range of the laser 110; - scanning of the laser 110 is started, at the end of which;

- the unloading arms 240 are brought into the gripping position (Fig. 5) where they pick up the sheet 1 and, rotating into the initial position, deposit it inside the unloading tray 212 of the sheet insertion/removal machine ;

- the container 310 is brought back into the initial position (Fig. 2) so as to prepare the plant for a new cycle . It is therefore clear how with the plant according to the invention it is possible to ensure an automatic and substantially continuous working sequence which reduces the cycle idle time, increasing at the same time the

precision and reliability of the process for incision/cutting of the sheet material.