DIE CUTTING MACHINE

Abstract: Automatic die cutting machine for making laminar labels, comprising a supporting frame (2), supporting a substantially horizontal surface plate (3), means for feeding a film (F) of laminar material step by step along a longitudinal direction (L), means comprising a pair of independent punches (8, 8') with blades (10, 10') reproducing the shape of the label to shear said film (F) forming one or more labels (T) at a time, staging means (9, 9') for the cut labels (T), and grasping means for removal and transfer of the cut labels (T) incorporated in the cutting means (8, 8'). Every punch (8, 8') includes elastic compensation means adapted to maintain the blades (10, 10') substantially parallel to the surface plate (3) and constantly in the predetermined tolerances.

Description: DIE CUTTING MACHINE Technical field The present invention relates to an automatic cutter machine for making laminar film labels, for example plastic film. Background art A known cutter machine of the type above indicated includes a surface plate, means for advancing the film step by step, cutting means, staging means of the cut labels, and grasping means for the removal and transfer of the cut labels from the surface plate to the staging means. The labels produced with machines of the type above described can be used in various sectors, for example in the graphics and paper industry, in the food industry, in commerce, in offices, schools, houses and in recreational activities. Depending on their use, the labels can be previously printed or coloured. Moreover, they can be made adhesive in which case they are supplied on a paper support. A particular application field of remarkable interest for the present invention is that of machines for making plastic film labels to be integrated in multilayer products, like food containers, for decorative purposes and/or for identification of food, for example in accordance with the Italian patent application No. VI95A000142 and with the international application No. PCT/EP96/03994. It must be observed that this label type is used in a free state, i.e. not anchored to any support, because it must be inserted between the different layers so as to be clearly visible from the outside. Several punch cutter machines of the above indicated type are known which, though satisfactorily fulfilling their tasks, have some recognised drawbacks. A first drawback is the limited flexibility, for the fact that the known machines cannot make labels of reduced thickness and/or of irregular forms, as for example plastic film labels without adhesive support. Another drawback of the known machines is their low productivity because of the necessity of frequent stops for regulation of the blades, which regulation must be periodically carried out through complex and costly gauging operations to maintain the narrow planarity tolerances in relation to the surface plate. Another drawback of the known machines is in the fact that often the thinner labels have the tendency to wrinkle, thus forming folds during the release or the deposition in the stoking storages, making often unusable the whole stack of labels. Moreover, the known machines have a remarkable complexity that increases building, management and maintenance costs. A primary object of the present invention is to overcome the above lamented drawbacks by providing a cutter machine with high efficiency, productivity and reliability. A particular aim is to provide a cutter machine that allows cutting labels from films of extremely reduced thickness and doesn't require frequent regulations of the blades. Another aim is to provide an automatic machine that allows making high quantities of blanks in extremely short times, perfectly stocked and ordered in packs ready for their insertion in other machines or production cycles. In accordance with a preferred aspect of the present invention, there is provided a cutter machine as defined in the preamble of the appended claim 1 , and which is characterised by the fact that the grasping means are incorporated in the cutting means, and can be activated immediately after the cutting operation. Thanks to this disposition, the productivity of the machine remarkably increases with a consequent production cost reduction in comparison with the known machines of the past. According to a further aspect of the invention, means for elastic compensation of the blades are provided, to maintain the latter in an optimal position with respect to the surface plate during label cutting. Thanks to such characteristics, substantial elimination of the parallelism error between the blade and the surface plate is accomplished, allowing the perfect shear of films of very reduced thickness without any intervention for periodic regulation and/or gauging of the blade for maintaining the foreseen tolerances. Brief description of the figures Further characteristics and advantages of the invention will become more apparent in light of the detailed description of a preferred but not exclusive embodiment of a cutting machine according to the invention illustrated with the help of the attached drawing sheets in which: the FIG. 1 shows a schematic lateral view of a machine according to the invention in a first operative position; the FIG. 2 shows a global upper plan view of the machine of Fig. 1 in a second operative position; the FIG. 3 shows a sectional side view of a detail of the machine of Fig. 1 , according to a vertical plan; the FIG. 4 shows as axonometric schematic view of an other detail of the machine of Fig. 1 ; the FIG. 5 shows a sectional lateral view of the detail of Fig. 4. Description of the invention With reference to the cited figures, a cutter machine according to the invention, globally designated by the reference numeral 1 , comprises a supporting structure 2 substantially in the form of a cage made of metal beams supporting a surface plate 3 defining at the upper side a shearing zone 4 of the machine. At one extremity of the supporting structure 2, there is mounted a roll 5 of film F of the chosen material for the manufacture of the labels T. This film can even have an extremely reduced thickness, for example lower than 40 μm. The advancing of the film F on the surface plane along a longitudinal direction L is promoted by a pair of input rollers 6, 6' and by a pair of output rollers 7, 7' that are moved by a motor so as to impart to the film F step by step forward movements of length at least equal to that of the surface plate 3. Above the shearing zone 4 there are placed cutting means made of a pair of punches 8, 8' alternately and sequentially interactive with the surface plate 3 for shearing the labels. Every punch 8, 8' is associated to grasping means adapted to automatically withdraw, transfer and release the shorn label from the shearing zone 4 to storages 9, 9' . According to the invention, the grasping means are incorporated in the cutting means, and can be activated immediately after the shearing operation. In other words, the cutting means and the grasping means are integrated in only one assembly so as to act selectively and in very short times, in succession, substantially reducing dead-times of the machine. In particular, each punch 8, 8' supports one or more blades 10, 10' reproducing the shape of the label to be cut, fixed in a generally wooden board 1 1 , 1 1 ' . Opportunely, every board 1 1 , 1 1 ' is provided with through apertures 1 2 uniformly distributed inside the area enclosed in the blades 10, 10' for the passage of aspirated or blown air. In turn, each board 1 1 , 1 1 ' is anchored, for example by connecting screw organs, to respective flat plates 1 3, 1 3' of rigid material, for example light alloy. According to the invention, each flat plate 13, 13' of each punch 8, 8' constitutes also the grasping means as it is provided with a channels or compartments net 14, clearly visible in the Figure 3, united to one or more extremity pipe joints 15. The latter can be selectively connected by a flexible piping to the aspiration or outlet joints of a pneumatic exchange, not shown in the figures. Accordingly, the labels obtained by the cutting action of the punches 8, 8' will be drawn by aspiration inside the spaces delimited by the blades 10, avoiding the introduction of a separate grasping means, typical of the machines of the past, with a drastic consequent reduction of the operation time. According to the invention, there are provided elastic compensation means adapted to maintain the blades 10, 10' substantially parallel to the surface plate 3 and constantly within the predefined cutting tolerances. Such elastic compensation means include for each blade 10 a first multilayer element 1 6 interposed between the board 1 1 and the respective plate 13, 13' having a sandwich structure constituted by a pair of steel sheets 1 7, 1 7', between which one or more layers 1 8 are interposed, which are made of elastically yielding material of non-woven fabric, for example polypropylene, with Shore hardness index greater than 1 20°, preferably comprised between 140° and 1 50° Shore. In particular, the first multi-layer element 1 6 extends peripherally along the back of each blade 10, 10' and interacts with the latter at the moment of cutting in order to transmit to it the cut stress uniformly, allowing little position changes to favour automatic adaptation of the blade 10, 10' with respect to the surface plate placed below. Moreover, the elastic compensation means include a second multi-layer element 1 9 mounted below the surface plate, with a sandwich structure similar to the one of the first element 16 with which it co-operates to favour automatic adaptation of the blade during label cutting. There are provided longitudinal guides 20 for making the punches 8, 8' slide by means of actuators 21 that alternately move the punches in translation along the longitudinal direction L bringing them selectively on the cutting zone 4 facing the surface plate 3, while the other punch lays above one of the storages 9, 9'. Such lateral storages 9, 9' are positioned to the opposite longitudinal extremities of the machine. Every storage 9, 9' includes a pair of staging planes, respectively 22, 22' and 23, 23', moving transversally and alternately according to a predetermined sequence between an stacking position of the cut labels T and an unloading position of the pack P of stacked labels T. The staging planes 22, 22' and 23, 23' can be supported elastically by respective compression springs 24 and moved by respective actuator means 25, visible in Figure 1 , adapted to lower the planes 22, 22', 23, 23' on increase of the quantity of stacked label T so as to maintain the maximum height W of the pack of stacked labels P approximately constant. According to the invention, each staging plane includes a plurality of retractile pins 26 placed along the periphery of the label stacking zone and jutting vertically towards the upper side. During the release of the label in the accumulation pack, the pins 26 interact elastically with the board 1 1 of the punch, retracting towards the lower side so as to maintain substantially constant the minimum distance D between every punch and the last label laid on the pack P. More precisely, the pins 26 are mounted on springs 27 and protrude from the respective staging plane for a height H greater than the maximum height W of the labels pack P, as shown in Figure 5. In order to automatically cut the labels, there is provided a pneumatic or hydraulic cylinder 28, of large diameter, anchored with its axis vertical to the supporting structure 2, guided by a series of vertical pillars 29. The cylinder 28 interacts cyclically and alternately with the punches 8, 8' compressing them at first against the surface plate 3 so as to cut the film, and releasing them to allow their transfer towards the respective label storage 9, 9'. More precisely, after every shearing each punch 8, 8' is displaced in translation towards the upper side by elevator means 30 until it is placed on the longitudinal guides 20 along which it is automatically moved in translation towards the respective cut labels collecting storage 9, 9" . Opportunely, there is provided a microprocessor control unit, not shown in the figures, and within the skills of any person skilled in the art, which controls the feeding of the different actuators so as to determine cutting, extraction and unloading of the labels on the lateral storages 9, 9', as well as the alternate moving of the punches 8, 8' and of the staging planes. Moreover there can be provided a relaxation unit 31 to cancel the elastic memory of the film F and make it perfectly plane before its introduction in the cutting zone, corresponding to the surface plate 3. More particularly, the relaxation unit 31 includes a chamber 32 crossed by a blow of hot air with temperature comprised between 30°C and 50°C and preferably close to 40°C, accommodating in its interior a plurality of moving rollers 33, fixed 34 substantially horizontally, placed in cascade, on which the film is made to run so as to undergo folding in both senses while it remains immersed in the blow of hot air. During use, after the film F has run in the relaxation unit 31 and has been introduced in the cutting zone 4, and one of the punches 8 is above the surface plate 3, the cylinder 28 compresses downwards the same punch 8, causing the simultaneous shearing of the labels T. Immediately after, air is aspirated from the plate 13, raising the shorn labels T against the same punch 8. At this stage, the actuator means 21 cause the translation of the punch 8 bringing it in alignment with the storage 9 and bearing at the same time the punch 8' in alignment with the surface plate 3. Air under pressure is then sent to the plate 1 3 that causes unloading of the label on the storage 9 and the stacking on the respective staging plane 22. Subsequently such operations are repeated on the plate 13' when the latter is aligned to the storage 9' . When the pack P is completed on every staging plane 22', the latter is translated in transversal direction so as to free a plane preparing it for the following cycle. Even if the cutting machine according to invention has been described with particular reference to the attached drawings, it is evident that it is subject to numerous modifications and variations, all entering in the scope of protection of the attached claims which are considered to be equally protected. The materials, the forms and the dimensions can be changed according to needs. The instant application is based upon Italian patent application VI98A000185, filed on 29 September 1 998, the disclosure of which is hereby expressly incorporated herein by reference thereto, and the priority of which is hereby claimed under 35 U.S.C. § 1 1 9.

Claims: CLAIMS 1 . Automatic die cutting machine for making laminar labels, comprising a supporting frame (2), supporting a substantially horizontal surface plate (3), means for feeding a film (F) of laminar material step by step on said surface plate (3) along a longitudinal direction (L), cutting means (8,8') adapted to interact with said surface plate (3) to shear said film (F) forming one or more labels (T) at a time, staging means (9,9') for the cut labels (T), grasping means for removal and transfer of the cut labels (T) from said surface plate (3) to said staging means (9,9'), characterised by the fact that said grasping means ( 13, 1 3') are incorporated in said cutting means (8,8'), and can be activated immediately after the cutting operation. 2. Machine according to claim 1 , characterised by the fact that said cutting means include at least a pair of independent punches (8,8') alternately and sequentially interacting with said surface plate. 3. Machine according to claim 2, characterised by the fact that every punch (8,8') includes one or more cutting blades (10, 10') reproducing the first label to be cut, said blades ( 10) being fixed on a respective table ( 1 1 ) anchored in turn to a respective plate (1 3, 1 3') defining said grasping organs. 4. Machine according to claim 2, characterised by the fact that every punch (8,8') includes elastic compensation means adapted to maintain said one or more blades ( 10, 10' ) substantially parallel to said surface plane (3) and constantly in the predetermined tolerances. 5. Machine according to claim 4, characterised by the fact that said elastic compensation means include, for every blade (10, 10'), a first multilayer element ( 1 6) interposed between said table ( 1 1 ) and said plate ( 13), and having a sandwich structure constituted by a pair of steel sheets ( 1 7, 1 7') between which one or more sheets (1 8) of elastically yielding material are interposed. 6. Machine according to claim 5, characterised by the fact that said one or more sheets (18) of elastically yielding material are of polypropylene non-woven fabric with Shore hardness index greater than 1 20 and preferably comprised between 140 and 1 50. 7. Machine according to claim 5, characterised by the fact that said first multilayer element (1 6) is perimetrally extended along the back of said blades (10). 8. Machine according to claim 1 , characterised by the fact that said elastic compensation means include a second multilayer element ( 1 9), mounted below to said surface plate (3), with a sandwich structure of the same type as that of said first element ( 1 6). 9. Machine according to claim 3, characterised by the fact that said plate ( 13) provides a series of canalizations ( 14) connected to at least one pipe fitting of aspiration/compression ( 1 5) and is removably anchored to said table (1 1 ). 10. Machine according to claim 1 , characterised by the fact that said staging means include a pair of lateral storages (9,9') associated to said at least one pair of punches (8,8'), with respective staging planes (22, 22' , 23, 23') adapted to support groups of stacked labels, said staging planes being positioned at the longitudinal extremities of the machine. 1 1 . Machine according to claim 2, characterised by the fact that said punches (8,8') can slide along longitudinal guides (20) by means of actuating means (21 ), so as to align selectively ones of said punches (8,8') to said surface plate (3) while the other punch is aligned with one of said lateral storages (9,9'). 1 2. Machine according to claim 10, characterised by the fact that said lateral storages (9,9') include two pair of staging planes (22, 22', 23, 23'), transversally and alternately moving between a stocking position of the labels and an unloading position of the pack of stocked labels. 1 3. Machine according to claim 1 , characterised by the fact of providing on each staging plane (22, 22', 23, 23') a plurality of pins salient toward the upper part in peripheral positions to said label stocking zone (T), said pins (26) being adapted to interact elastically with a respective punch (8,8') on release of the cut labels and to withdraw elastically towards the lower part to maintain the distance (D), between every punch (8, 8') and the latest label stacked on the pack (P) substantially constant and minimal. 14. Machine according to claim 1 3, characterised by the fact that said staging planes (22, 22', 23, 23') are mounted on a series of elastic supports (24) . 1 5. Machine according any one or more of the previous claims, characterised by the fact of providing at least a pneumatic or hydraulic cylinder (28) adapted to selectively compress said punches (8,8') against said surface plane (3) when they are aligned with the latter. 1 6. Machine according to one or more of the previous claims, characterised by the fact of providing control means connected to pneumatic means to set under depression one of said plates ( 1 3, 1 3') when the respective punch (8,8') is superposed to the surface plate (3) so as to removal the cut labels, and to pressurise the other of said plates ( 1 3, 1 3') that is superposed to one of said staging planes (22, 22', 23, 23') so as to unload the withdrawn labels.

Inventors: RIGLIETTI ANTONIO, RIGLIETTI, ANTONIO
Applicants: RIGLIETTI ANTONIO, RIGLIETTI, ANTONIO
Application year: 1999
Main classification: B26F1
IPC codes: B26D7, B26F1