METHOD AND APPARATUS FOR LOADING LABELS INTO A MOULD OF A THERMOFORMING MACHINE

Abstract: A method and apparatus (3) for loading pre-punched and three-dimensionally pre-shaped labels (19) into a female mould or die having one or more forming cavities (9) in a thermoforming machine or press for obtaining labelled hollow objects with a bottom wall, such as beakers, cups, basins, trays, vases and the like starting from a sheet or tape (5) of thermoformable material.

Description: METHOD AND APPARATUS FOR LOADING LABELS INTO A MOULD OF A THERMOFORMING MACHINE The present invention relates to a method and an apparatus for loading pre¬ punched and three-dimensionally pre-shaped labels into a female mould or die 0 having one or more forming cavities in a thermoforming machine or press for obtaining hollow objects with a bottom wall, such as beakers, cups, basins, trays, vases and the like starting from a sheet or tape of thermoformable material. It has already been proposed in the thermoforming art to load into the female or double female mould a label before carrying out the thermoforming process of 5 an object or objects, so as to cause a close and permanent adhesion obtained under heat and pressure conditions between label loaded into the or each forming cavity of the mould and outer surface of the respective object thermoformed in the forming cavity - see for instance Italian patent application no.VR94A000014 filed on February 24, 1994 in the name of the applicant. 0 More particularly, when tray or jar articles being polygonal (typically square or rectangular) in plan view are to be thermoformed, one proceeds with die-cutting of the labels, each of which thus has a central square or rectangular area that is designed to cover the outer surface of the bottom of a thermoformed container and from each side of which four lateral flaps or wings extend outwards. Between each 5 pair of adjacent side flaps an enlarged recess is provided at the central zone, which is arranged to form after thermoforming of the tray or jar a receiving seat of a respective rounded corner between the bottom and two adjacent side walls of the tray, corner that is designed to remain "uncovered", i.e. not affected by the label. With the solutions put forward up to now, however, undesired inconveniences 0 may occur at the rounded lateral corner of the tray or jar, where not infrequently misalignments, wrinkles and other visible defects in the positioning of the edges of the label on the thermoformed object, even if the corners of the object, and thus those of the mould, are rounded with a wide bending radius. Useless to say that - 2 - such defects affect the quality level of the manufactured object and result in a high rate of rejected items, waste of materials and decrease in productivity. This occurs because each pre-punched label, before being laid in a respective forming cavity of the female mould, is first withdrawn by means of a respective sucking plug arranged to engage the central zone of the label and to transfer and load it into the mould, the said plug having substantially the same configuration as a counter-die or male mould for the female mould. The label is then placed in a pre-shaping template having a homothetic configuration to that of the female mould in order to force the side wings of the label to adhere to the sucking side faces of the respective plug element before being transferred, Iocated and released in a respective moulding cavity in the female mould. During this operation the side wings of the label are simultaneously subjected to a severe constraint while being inserted into the pre-shaping template, and thus, also owing to unavoidable although small positioning inaccuracies, the pairs of adjacent side wings often engage with one another during the relatively rapid bending towards the side walls of the plug to which they are subjected, thereby producing showy wrinkles and ill-shaped overlapping that are unacceptable for aesthetic purposes. Moreover, it has already been suggested in the thermoforming art to load a label into the or each forming cavity of a double-female mould before obtaining the object or objects by a thermoforming operation. While the thermoforming process is being carried out deep and permanent heat adhesion under pressure occurs between label pre-loaded into the or each forming cavity of the mould and outer surface of the respective object being thermoformed in the same forming cavity, e.g. as disclosed in the patent application nr.VR94A00O014 filed on February 24, 1994 in the name of the applicant and relating to an "apparatus for loading labels into a double-female die of a thermoforming machine". Such a loading apparatus, however, is designed to load labels into a double- female die when the female dies, in turn, move laterally to a rest position out of vertical alignment with the male die, so as to be easily accessible from above and in any case not obstructed by the presence of the male die. Thus, that apparatus is unsuitable and does not land itself to the loading of labels in single-female die thermoforming apparatuses, in which the female die moves only axially to and from the male die. It has already been suggested - see patent application MI94A000767 filed on April 24, 1994 in the name of SY.TRA.MA. s.r.l. - an apparatus for positioning label in thermoforming dies, which comprises, in sequence, a first storing station for the labels to be loaded, a second station of correct positioning of each label withdrawn from the storing station, and a third shaping station for folding the labels coming from the correct positioning station before transferring them to a female die. With the Sy.tra.ma. apparatus loading of the labels into the die occurs after rotation through 90° of both the female die with respect the male die and the loading group, which obviously involves considerable construction complications in the support structure for the female die and handling and synchronisation problems in linear displacements for some components of the apparatus and in linear displacements for others. As a matter of fact, setting and synchronisation of an apparatus of this type having, as already said, a high number of work stations and female die, and the more so if designed to effect angular displacements, require a minimum time of a few hours, but sometimes of a few days both during initial installation and especially at each change of thermoforming die. The main object of the present invention is to eliminate or drastically reduce the drawbacks referred to above in connection with the solutions put forward up to now by providing a method and an apparatus for loading labels into a single- female die in a thermoforming machine or press, where a reduced number of work stations is provided. Another object of the present invention is to make it possible a quick and accurate setting of the label loading apparatus both upon initial installation and while changing the die, thereby ensuring an almost constant production without heavy dead times of perfectly labelled thermoformed objects. According to a first object of the present invention there is provided a method for loading labels into a mould including a single-female die and a counter-die or male die of a machine or press for thermoforming hollow objects with a bottom wall from a sheet or strip of thermoformable material fed between female die and counter- die, which comprises laying a number of labels equal the number of forming cavities onto a respective seat of a dummy female die for centering or correctly setting the labels, three-dimensional pre-shaping of the labels in the same dummy female die, transfer of the thus pre-shaped labels from the dummy female die to the to the zone delimited on the one side by the female die and on the other from the sheet and the counter-die, removal of the or each previously thermoformed object from the female die, and loading of the pre-shaped labels transferred from the dummy die into a respective forming cavity of the female die. Such a method ensures the considerable advantage of adopting a maximum of only two work stations for holding, laying and pre-shaping the labels for preparing them to be loaded into the female die which remains always axially aligned in front of the counter-die. According to another aspect of the present invention there is provided an apparatus for loading labels into a mould including a single female die and a counter-die or male die for a machine or press for thermoforming hollow objects having a bottom wall starting from a sheet or strip of thermoformable material fed between female die and counter-die, which apparatus has a label feeder and is characterised in that it comprises a dummy female die having a label shaping cavity or cavities homothetic to those of the female die and being each formed with a top receiving seat for temporarily receiving and centering labels in a bidimensional configuration, and a shaping and transferring plug for each seat of the dummy die, which is designed first to push the labels centered on the top of the dummy die in a respective seat for being three-dimensionally pre-shaped and subsequently for transferring them in the pre-shaped configuration to the zone between female die and counter-die and then laying the same in the female die. Advantageously, the said label feeder comprises a punching-cutting group acting on a continuous label tape. Further aspects and advantages of the present invention will better appear from the following detailed description of some at present preferred embodiments of a label loading apparatus, given by way of non limiting examples with reference to the accompanying drawings, in which: Figure 1 shows a diagrammatic front elevational view a thermoforming plant comprising a thermoforming machine having a single-female die and a label loading apparatus with two work stations in accordance with the present invention; Figure 2 is a partial top view of the plant of Fig. 1 ; Figures 3 and 4 show each a view in an enlarged scale of a detail concerning the label loading apparatus of the plant of Fig. 1 in a different operation stage; Figure 5 shows a cross-sectional view taken along the line V-V of Fig. 1 on a slightly enlarged scale and with parts half in cross-section in an operative position and half in a different operative position; Figure 6 is a partial diagrammatic view in cross-section of a dummy die having a bidimensional label disposed in a centering seat on the top of a cavity or recess thereof, whereas a shaping and transferring plug is approaching from above; Figure 6A is the same view as Fig. 6 but with the shaping plug inserted into the dummy die and three-dimensionally pre-shaped label; Figures from 7 to 11 are each a diagrammatic side elevational view which shows the plant in sequentially operational stages subsequent to that illustrated in Fig. 6; Figure 7A shows a variation of Figure 7, in which it is the dummy die that moves with respect to the shaping plug or plugs; Figures 12 and 13 are diagrammatic front elevational views with parts in section, which illustrate another embodiment of label loading apparatus in two different operative operation stages; Figures 14 and 15 are diagrammatic front elevational views of a further embodiment of the label loading apparatus in two different operation stages and with a different type of label feeder from a shearing machine belonging to the label loading apparatus; Figures 16 and 17 are diagrammatic elevational views of a further embodiment of the label loading apparatus from an outside shearing machine operating in sequential cycle with it; Figure 18 shows a detail in cross-section of Fig. 16; and Figures 19 and 20 show a further embodiment of label loading apparatus with label feeder coming from an outside shearing machine operating in sequential cycle with it. Figure 21 is a perspective diagrammatic view of a seat of a pre-shaping template or dummy die for labels to be applied to a basin or tray container being rectangular in a plan view; Figure 22 is a top view of a punched label for a basin container being rectangular in plan view; Figure 23 is a top view of the pre-shaping seat of Fig. 21 having a sucking plug or counter-die inserted therein and bearing a punched label of Fig. 22; Figure 24 shows a detail in section of Fig. 23; Figure 25 shows a perspective view of the sucking plug of Fig. 23 having a label partly adherent thereon after withdrawal from a pre-shaping template; Figure 26 is a plan view of the sucking plug of Fig. 25; and Figure 27 shows a front elevation view of the sucking plug of Fig. 26. In the accompanying drawings equal or similar parts or components have been indicated with the same reference numerals. With reference first to Figures 1 to 11 it will be noted that a thermoforming plant, generally indicated at 1 , comprises a thermoforming press or machine 2 interlocked with a label loading apparatus 3 for obtaining externally labelled hollow objects having a bottom wall starting from a continuous sheet or tape of thermoformable material fed by an upstream Iocated group 4 arranged to feed a hot tape of thermoformable material, e.g. forwarded to the thermoforming press 2 by means of a chain conveyor 6. The thermoforming machine includes a mould comprising a single-female die, e.g. arranged below, and a counter-die or male die 7 arranged above the female die in vertical alignment therewith. The female die is mounted in such a way as to be able to move axially away from and towards the counter-die 7 between a closed position against the counter-die and an open position below and away from it. Actuating means, e.g. of conventional type well known in the art, and thus not described in detail, are provided for moving the female die. Of course, the female die could also be arranged above the male die 7 depending upon design requirements. The female die has one or more forming cavities 9, each of which is provided with a respective mobile bottom wall 10 which is vertically movable in order to remove or lift a thermoformed object, such as a round-corner basing 11 rectangular in top view, from the female die. To this end, suitable drive means (not shown in the drawings) is provided for each mobile bottom wall of the female die, as it is known in the art. The male die comprises as many counter-dies as are forming cavities in the female die, which are arranged vertically displaceable within a respective receiving seat 12 formed in a head block having outer overall dimensions equal to and complementary with that of the female die 8. Each seat 12 also locates a hollow punch cutter, generally indicated at 14, which is designed to cut the rim of an object 11 just formed before the mould is opened in order to separate it from the scrap sheet 15 that will be moved away from the thermoforming area by means of the chain conveyor 6 (Fig. 1 ). Upstream of the thermoforming area at the dies 7 and 8 there is advantageously provided a suitable conveyor 16 for moving away the objects 11 loaded onto it at the thermoforming area. Downstream of the thermoforming area there is arranged the label loading apparatus 3 which comprises a support structure 17 for two stationary work stations, i.e. a store 18 for bidimensional piled up labels 19 and a dummy female die 20 arranged between the female die 8 and the store at the same distance therefrom. Of course, there is provided the same number of stores 18 and shaping cavities 21 in the dummy die 20 as that of the forming cavities in the female die 8. Each shaping cavity 21 has at the top thereof a peripheral seat 22 arranged to temporary receiving and centering a label 19 of bidimensional configuration, as will be further explained below, whereas from the bottom a support engagement means, e.g. a support and guide plate 23, for a label loaded into the seat 22 can be raised and lowered, which is, for instance, carried on the end of a piston rod of a fluidynamic cylinder and piston group 24 and guided by guide rods 25. Each store 18 is designed to be loaded preferably automatically by suitable loading means, not shown in the drawings, with a predetermined number of stacked labels, the uppermost label being automatically brought to a predetermined level in its respective store by any suitable means. Above the dummy die 20 and the store or stores 18, and thus above the support structure 17, there is provided a stationary support and sliding guide 26 which extends in a direction normal to the axial plane containing the male die 7 and the female die 8. A carriage or slide 27 is slidably mounted on the guide 26 and carries a depending vertical arm or slide 28 which supports underneath a transversal contraction-expansion mechanism 29 adjacent to the thermoforming machine 2 and a rear cross member 30 which extend horizontally and peφendicularly to the guide 26. The contraction-expansion mechanism 29 is designed to support a shaping and transfer plug 31 for each shaping cavity 21 in the dummy die 20 arranged below it and to cause a contraction or reciprocal moving closer of the plugs 31 before or during the return stroke, as will be further described below, whereas the rear cross member 30 supports one or a plurality of suction cups 32 controlled by a suitable vacuum source, not shown, for withdrawing labels from the stores 18 and transferring them to a respective receiving seat 22 in the dummy die 20. The carriage or slide 27 is actually provided with suitable drive means, such as a motor-reduction unit 33, for its backwards and forwards movements, and thus in both directions (double arrow X) along the guide 26, whereas the contraction- expansion mechanism 29 and the cross member 30 move vertically together (double arrow Y) while being guided along the arm 28, e.g. by means of suitable drive means, such as one or a pair of fluidodynamic piston and cylinder groups 34. The distance between the plugs 31 and the sucking cups 32 is maintained constant and equal to that between the dummy die 20 and the stores or the dies 7 and 8. The side walls of the shaping plugs 31 have a plurality of holes (not shown in the drawings) in communication with a suitable vacuum source and a source of fluid (air) under pressure (both not shown). Similarly, the plate 23 or another support means in each shaping cavity 21 in the dummy die 20 communicates through its hollow guide rods 25 with a fluid source, also not shown, for purposes that will be explained below. Of course, the whole operation of the plant is controlled by an electronic control unit, not shown. With a thermoforming plant such as that described above starting from the situation illustrated in Fig. 3, i.e. with sucking cups 32 that after having been lowered and set in a sucking condition have just been lifted above the stores 18, from where they have withdrawn a plurality of labels 18, while at the same time the plugs 31 have come out from a respective shaping cavity 21 of a dummy die and have changed their mutual distance, i.e. they have move closer to one another, the mould of the thermoforming machine 2 is been opened, i.e. the female die 8 has been lowered, thereby causing at the same time its mobile bottom walls or extractors 10, that carry the thermoformed objects 11 in the respective forming cavities 9, to raise to a level slightly higher than the free edge of the respective forming cavities 9. At this point a motor-reduction unit 33 is energised, which results in the carriage 27 being moved forwards towards the thermoforming press 2, thereby reaching the condition illustrated in Fig. 4, where the sucking cups with the plane labels 19 carried by them are arranged axially vertically aligned above the dummy die 20, whereas the contraction-expansion mechanism 29 has moved to the thermoforming area above the female die 8 (now in its lowered position) and below the sheet 5 and the upper counter-die 7. During its insertion movement between the dies the contraction-expansion mechanism 29 by means of a front lug or lugs 35 pushes the object or objects 11 while supported by their respective extractors 10 away from the forming cavities of the female die 8 and transfers them onto the adjacent conveyor 16, thereby freeing the space above the extractors 10 which are thus ready to be lowered into their respective forming cavities in the female die 8 for receiving a respective pre-shaped label 19 which is brought by one of the plugs 31 carried by the contraction-expansion mechanism 29, as will further described below. Of course, the movement of the thermoformed and externally labelled objects can occurs by using any suitable different from lugs 35, such as one or more air jets, an engaging arm for the objects, sucking cups and the like. At the end of the feeding forward movement of the carriage 27 the fluidodynamic groups 34 are activated in order to cause lowering of both the contraction- expansion mechanism 29 and the cross member 30 (Fig. 10) so as to insert the plugs 31 with the pre-shaped labels 19 adhering thereto into a respective forming cavity in the female die 8 and to load at the same time the plane labels 19 carried by the sucking cups 32 into their respective receiving seats 22 in the dummy die 20 after their respective plates 23 have moved to a height corresponding to the bottom of the seats 22 in order to assist in supporting the labels 19 in a plane and centered arrangement. At the end of the lowering movement of both the contraction-expansion mechanism 29 and the cross member 30 air under pressure is supplied to the plugs 31 in order to cause the release and the laying of the pre-shaped labels 19 accurately adhering to the side walls of their respective forming cavities 9 which is already in a depression condition and the plates 23 are set in communication through their respective tubular guides 25 with the vacuum source so that the plates can develop a sucking action onto the label 19 before the same is released by the sucking cups 32, thereby the label after a possible initial centering in its respective seat 22 is permanently engaged, and thus no longer free to move randomly, by some component of the loading apparatus. A reverse vertical lifting movement is then caused by the fluidodynamic groups 34 in order to arrange the loading apparatus in the attitude illustrated in Fig. 11 and the return movement of the carriage 27 is effected in order to carry the empty plugs 31 and sucking cups 32, respectively, above the dummy die 20 and the store 18. Meanwhile, the male and female dies (after a predetermined step forward of the sheet 5 by means of the chain conveyor 6) are caused to close onto one another by the electronic control unit in order to obtain a moulding of objects 11 (Fig. 7). Once the return stroke of the carriage 27 has been terminated and the contraction- expansion mechanism 29 has expanded, thereby increasing the distance among the plugs 31 , the fluidodynamic groups 34 cause vertical lowering of the plugs 31 against a respective flat label 19 placed in the seat 22 underneath of the dummy die 20, whereas the sucking cups engage the uppermost label in the label stake in the store 18 underneath. As shown in Fig. 7, each plug 31 during its descent abuts against a respective pre-punched flat label and pushes it, while being assisted by the engagement means or plate 23 underneath into a shaping cavity 21 of the dummy die 20, thereby deforming it and forcing it to take a three-dimensional configuration with its bottom portion resting on the plate 23 and abutting against the Iower face of the plug 31 and its side walls standing with respect to the bottom portion and inserted in a gap between the corresponding side walls of the forming cavity 21 and the side walls of the plug 31. Once the descent stroke is terminated, the holes opening both on the front wall and on the side walls of each plug 31 a set into communication with a vacuum source to cause the now three-dimensional ly configurated labels 19 to stably adhere to their respective plug 31 , and then the tubular guides 25 of the plates 23 are set into communication with the atmosphere, thereby releasing the labels in the shaping cavities 21 from their respective plate 23. At the same time the sucking cups 32 are se into communication with a vacuum source in order to engage the uppermost labels in the various stores 18, after which a lifting stroke of the contraction-expansion mechanism 29 with its plugs 31 loaded with a pre-shaped label 19 and of the cross member 30 with its sucking cups carrying flat labels 19 (Figs. 3 and 8) The dies 7 and 8 are then caused to move apart from one another, i.e. the die 8 moves downwards with respect to the counter-die, while the objects 11 are extracted from the forming cavities 9 of the female die by the extractors 10 before the beginning of a new stroke of the carriage 27 towards the thermoforming machine 2 (Fig. 9) to transfer the labels thus pre-shaped carried by the plugs to the zone between the female die and the counter-die and the flat labels carried by the sucking cups above the dummy die. And so on for successive operation cycles of the thermoforming machine. In the embodiment shown in the Figures 12 and 13 the contraction-expansion mechanism 29 and the cross member 30 carried by the slide 28 perform only horizontal movements in the direction of the double arrow X parallel to the guide 26. The dummy die 20 and the store 18 are instead supported by a platform 36, which is movably mounted in a (vertical) direction normal to the direction X along guides 37 slidably mounted in respective fixed sleeves 38 carried by the support structure 17. The movements of the platform 36 are controlled by a suitable reversible actuator, e.g. a fluidodynamic cylinder and piston group 39 having, for example, its cylinder secured to the support structure 17 and its piston rod connected to the platform 36. In other words, the reciprocal approaching and departing movements among the plugs 31 and dummy die on the one side and among the sucking cups 32 and the store 18 on the other side are performed by the dummy die 20 and the store 18, whereas the plugs and the sucking cups are stationary. The same kind of vertical movement of the dummy die 30 is provided in the embodiment of Fig. 7A. In the embodiments illustrated in Figures 14 to 20 instead of the store 18 there is provided a cutting-punching group, generally indicated at 43, e.g. of a suitable type well known in the art, arranged to cut and punch the labels 19 from a continuous sheet 44 being fed stepwise on a resting plane 45 on which a cutting roller 46 can move backwards and forwards. Figures 14 and 15 show an embodiment of a label loading apparatus as that shown in Figures 3 and 4, but equipped with a cutting-punching group 43. In the embodiments of Figures 16 to 20 the work station comprising the dummy die 20 is mobile, i.e. the dummy die 20 is movably arranged on the support structure 17 in a direction parallel to that of the sliding guide 26 between a laying position for the flat labels 19 into the seat or seats 22 relatively far away from the thermoforming press 2 and a pre-shaping position of the labels by means of a respective plug 31 near to the thermoforming machine. More particularly, in the embodiment of the Figures 16 to 18 the dummy die 20 is supported by a slide or carriage 40 which can slide on fixed guides 41 carried by the support structure 17 and extending parallel to the guide 26 and is controlled by a suitable reversible linear actuator (not shown in the drawings). The length of the stroke between the laying position and the pre-shaping position is equal to backward and forward movements of the carriage 2. In the laying position the dummy die 20 is loaded by an upper head 42, e.g. comprising sucking cups or other suitable means, such as those of plate type axially displaceable upon control, which can move between the laying position and a withdrawal position of flat labels 19 at the cutting-punching group 43 arranged to cut and punch the labels from a continuous tape 44. The movement of the head 42 can occur along one or more fixed sliding guides 47 parallel to the guides 41 or, if desired, by causing the head 42 to be angularly displaced along a circular path. In this embodiment the carriage 27 supports only the contraction-expansion mechanism 29 with its plugs 31 which can be displaced both in direction X (horizontally) for entering and coming out the thermoforming zone and in the direction Y (vertically) for pre-shaping the labels, whereas the dummy die 20 is in - 13 - the pre-shaping position (Figs. 18 and 17) and for the subsequent loading into the female die 8, while the dummy die 20 has been moved in the laying position (Fig. 16). Figures 19 and 20 show an embodiment in which the dummy die 20 is movably mounted on guides 41 of the support structure 17 and the cross member 30 of the sucking cups 32 is replaced by an arm 50 which is overhanging backwards with respect to the contraction-expansion mechanism 29 to support the sucking cups at a distance from the plugs 31 which is double the length of the stroke of the carriages 27 and 40. In all the embodiments described above the plugs 31 , as is better shown in Fig. 5, are movably supported on the contraction-expansion mechanism 29 so that they can be moved by any suitable linear actuator means in horizontal direction normal to the feeding direction along the guide 26 between an enlarged or expanded position (see the left half of Fig. 5) at the dummy die 20 and a contracted position (see the right half of Fig. 5) at the thermoforming zone. This because the distance among the various shaping cavities 21 of the dummy die is considerably greater than that among the forming cavities 9 in the female die, since the shaping cavities 21 must receive the labels 19 in a flat not pre-shaped condition in their respective top seats 22. To this end, the various plugs 31 are slidably supported on cross guides and controlled by a reversible linear actuator, not shown in the drawings, b As it is illustrated in Fig. 1 , at each of the two work stations 20 and 18 centering means can be provided, e.g. comprising one or more tubular reference seats 55 with a vertical axis secured to the support structure 17 and as many matching pins 56 carried by the contraction-expansion mechanism 29 and extending downwards to enter the seats 55 in order to accurately center the plugs 31 in axial alignment with the shaping cavities 21 and the forming cavities 9. Figures 21 to 27 show another specific embodiment of a pre-shaping template or dummy die generally indicated at 60 having a number of seats 61 equal to the number of forming cavities 9 in the female mould 8 and homothetically arranged relative thereto. The dummy die 60 is designed to cooperate with a number of plug-like sucking elements 31 equal to that of the seats 61. - 14 - The transfer head is designed to withdraw a predetermined number of labels from a label feeder, insert them into a respective seat 61 of the pre-shaping template 60 so as to cause them to take a three-dimensional configuration against their respective sucking plug 31 , then withdraw and transfer the same to a respective forming cavity 9 of the female mould 8. As it is better illustrated in Fig. 22, should basin or tray containers being square or rectangular in plan view be labelled, each label 19 is previously punched so as to have a central zone 62 surrounded by two pairs of opposite side wings, respectively short 63 and long 64. The seats 61 of the shaping template or dummy die 60 have receiving shaping cavities 65 for three-dimensionally pre-shaping the labels 19, which at each corner thereof have a recess or escape 66 which is so shaped as to extend on the prolongation of side wall, e.g. the short one adjacent to the cavity 65 throughout the depth of the seat. Each recess 66 terminates short with a shoulder 67 substantially close to the position of maximum extension of an adjacent wing, such as a long wing 64 urged against the sucking plug 31 (Fig. 24). With this arrangement, when a label 19 withdrawn and kept adherent to the Iower front of a sucking plug 31 at its central zone 62 is forced to take a three- dimensional pre-configuration around the sucking plug following insertion of the sucking plug-label assembly in the cavity 65 of a seat 61 , the edges of the wings 63 are arranged against the side wall (that, if desired, can be provided slightly curved) of a respective recess 66. At the same time, the wings 64 of the label are urged against the side wall of the sucking plug 31. The latter is also formed with inner sucking ducts 68 which communicate through an upper duct 69 with a suitable vacuum source (not shown) and also reach the end portion of the long wings 64, whereas no sucking duct is provided at the recesses 66, where no sucking action is thus produced. Accordingly, the edges of the short wings are not urged towards the sucking plug, and thus the same remain slightly spaced apart from it even after removal from the pre-shaping template and during transfer to a forming cavity 9 of a female mould 8. The configuration taken is thus that illustrated in Figs. 25 and 26. During subsequent insertion into the female mould 8 the free edges of the wings 63 are caused to adhere around the sucking plug when the edges of the wings 64 already adhere to the sucking plug, and thus no interference can occur with the edges of the wings 64, but possibly overlap the edges of the wings 64 without resulting in wrinkles, pleats or other faults in the positioning of the label. Once the loading operation has been accomplished, the sucking plug is s automatically connected to a source of compressed air for releasing the label in work position inside the mould, ready to promptly heat-adhere to a basing or tray being thermoformed in the mould. The materials as well as the dimensions could be various depending upon requirements. o In the case of conical containers in the seat 65 of the shaping template or dummy die a single recess or escape 66 can be provided for laying in successive time phases two end edges of the label which must take a substantially slightly open frustoconical configuration before being loaded into the mould.

Claims: CLAIMS 1. An apparatus for loading labels into a mould including a female die and a counter-die or male die for a machine or press for thermoforming hollow objects having a bottom wall starting from a sheet or strip of thermoformable material fed between female die and counter-die, which apparatus has a label feeder and is characterised in that it comprises a dummy female die having a label shaping cavity or cavities homothetic to those of the female die, and a shaping and transferring plug for each seat of the dummy die, which is carried by a support structure movably mounted along a direction normal to the front of the thermoforming press, thereby being movable between a distal or extracted position with respect to the thermoforming machine in which it is in front of a respective shaping cavity of the dummy die to cooperate therewith to pre-shape and withdraw the labels pre-shaped in the dummy die, and a proximal or insertion position in the thermoforming zone between the female die and the sheet of thermoformable material in order to load the labels pre-shaped in, and withdrawn from the dummy die into the female die. 2. An apparatus as claimed in claim 1 , characterised in that each temporary receiving and centering seat in the dummy die is peripherally formed and in axial alignment with its respective shaping cavity underneath. 3. An apparatus as claimed in claim 1 or 2, characterised in that the shaping cavity of each dummy die is and being each formed with a top receiving seat for temporarily receiving and centering labels in a bidimensional configuration before being three-dimensionally pre-shaped in the shaping cavity underneath 4. An apparatus as claimed in any claim 1 to 3, characterised in that in each shaping cavity of the dummy die an engagement plate means is mounted for upwards and downward movements and is arranged to designed to move between an up most position in which it is flash with the bottom of the receiving seat on top of the shaping cavity thereof and a Iower position in which it acts as a bottom wall for its respective shaping cavity, the plate means having sucking bores arranged to be connected, upon control, to a vacuum source to engage an intermediate portion of a label centered in the top receiving seat and assist it while being inserted into the shaping cavity by a pushing plug. - 17 - 5. An apparatus as claimed in anyone of the proceeding claims, in which the or each shaping and transfer plug has holes that are connected upon control alternately to a vacuum source for withdrawing a respective label pre-shaped by it in a shaping cavity of the dummy die and to a compressed air source for releasing the same label in a forming cavity of the female die, characterised in that it comprises carriage or slide means designed to carry the said support structure, at least one support and sliding guide for the said carriage or slide means extending in a direction normal to the front of the thermoforming machine, and drive and control means arranged to control the movements of the said carriage and slide means along the or each support and sliding guide. 6. An apparatus as claimed in anyone preceding claim, characterised in that it comprises feeding means arranged to feed one label at a time to the centering or holding seat of each shaping cavity of the dummy die and designed to synchronously act with the or each plug and to move between a withdrawal position for withdrawing one or more labels from a label source, whereas the plug or plugs are Iocated at the dummy die, and a laying position for laying the labels into the respective centering seat, while the plug or plugs are inserted in the thermoforming zone. 7. An apparatus as claimed in claim 6, characterised in that the said feeding means comprise at least one store for a stake or pile of bidimensional labels and engagement and transfer means arranged to transfer the uppermost label in the or each stake to the centering or holding seat in a respective shaping cavity in the dummy die. 8. An apparatus as claimed in claim 6, characterised in that the said feeding means comprise a tape punching-cutting group and engagement and transfer means for transferring the labels punched out from the tape to the centering or holding seat in a respective shaping cavity in the dummy die. 9. An apparatus as claimed in claim 7 or 8, characterised in that the said engagement and transfer means comprises at least one withdrawing group secured to the said support structure, the distance between the sucking cup group and the plug or plugs being equal to that between the dummy die and store or cutting- punching group. - 18 - 10. An apparatus as claimed in claim 7 or 8, characterised in that the said engagement and transfer means comprises at least one sucking cup group, drive means arranged to cause the or each sucking cup group linear or angular movements between the withdrawal and laying position. 5 11. An apparatus as claimed in claim 10, characterised in that the said dummy die is movable between a loading or laying position in which it receives labels from the or each sucking cup group and a pre-shaping position in which it engages with the or each plug for pre-shaping the labels loaded therein. 12. An apparatus as claimed in anyone of the preceding claims, characterised in io that it comprises extraction or removal means for the objects thermoformed in the thermoforming press designed to act immediately before the said pre-shaping plug or plugs move to the insertion position at the thermoforming zone. 13. An apparatus as claimed in claim 12, characterised in that the said extraction or removing means comprises a pusher for the thermoformed objects which is movable 15 together with the pre-shaping plugs. 14. An apparatus as claimed in claim 12, characterised in that the said extraction or removal means comprises a holding arm or plate for the objects which is arranged to move to the thermoforming zone between male die and female die and to withdraw the thermoformed objects. 20 15. An apparatus as claimed in claim 12, characterised in that the said extraction or removal means comprises at least one nozzle designed to eject an air jet against the objects. 16. An apparatus as claimed in anyone claim 9 to 15, characterised in that it comprises drive means for the relative getting near and away synchronised 25 axially-aligned movements once between the dummy die and the plug or plugs and between the sucking cup group and the store or the cutting group and subsequently between the dummy die and the sucking group and the plug or plugs and the female die of the thermoforming machine. 17. An apparatus as claimed in claim 16, characterised in that the said drive means 30 comprises at least a linear actuator designed to act alt least on the dummy die or on the plug or plugs and on the sucking cup group. 18. An apparatus as claimed in anyone of the preceding claims, characterised in that it comprises centering means between the said dummy die and the plug or plugs and between the said store or cutting-punching group and the said sucking cup group. 19. An apparatus for loading punched labels into a female mould of a thermoforming machine as claimed in claim 1 , which apparatus comprises a label feeder, a pre-shaping three-dimensional template having a number of shaping seats equal to and arranged in an equivalent manner to the forming cavities in the female mould, at least one transfer head having a number of sucking plug-like or counter-die elements equal to that and arranged in the same way as the seats of the or the respective pre-shaping template and suitable for withdrawing the labels from the feeder, inserting them into a respective seat of the pre-shaping template and subsequently removing the same therefrom and transferring them into the forming cavities of the female mould, and being characterised in that the seats of the pre-shaping template have receiving cavities for a three-dimensional pre-shaping of the label on its respective sucking plug, which at each corner thereof are formed with a deep recess arranged to locate therein the edge of one of the wing of each pair of adjacent wings, so that such an edge is not caused to adhere to the sucking plug in the seat. 20. An apparatus as claimed in claim 19, characterised in that the or each recess is shaped so as to extend along the prolongation of a side wall of the respective pre-shaping template and terminate with a shoulder substantially close to the position of maximum extension an adjacent wing must take urged against the sucking plug. 21. An apparatus as claimed in claim 20, characterised in that the or each recess has its bottom wall slightly curved inwards to cause a slight bending in the wing of a label received therein to assist in its loading into the mould. 22. An apparatus as claimed in any claim 19 to 21 , in which the or each sucking plug has inner sucking ducts in communication with a vacuum source, characterised in that a number of such ducts open at zones arranged to act an end portion of two non adjacent wings of a label, whereas the same do not act on the zone or zones at the or each recess, thereby the edges if the short wings of the respective label do not undergo sucking action towards the sucking plug, but remain slightly spaced apart from it. 23. A method for loading pre-punched labels having a central zone and side wings into the forming cavity or cavities of a female mould, which comprises withdrawing the or each label by means of one or a respective sucking plug which engages the central zone of each label, inserting the or each sucking plug into a pre-shaping three-dimensional template having a number of seats equal to and having configuration not quite homothetic to that of the forming cavities of the female mould to be loaded, thereby bending the side wings of the or each label against the side walls of the or the respective plug, to which they adhere owing to depression, and is characterised in that it comprises - complete adhesion of only one of the edges of each pair of adjacent wings to each corner of the or each sucking plug, whereas the other edge remains slightly away from the sucking plug, - withdrawal from the pre-shaping template and transfer of the or each label in the state of not full adhesion to the or to the respective sucking plug, - insertion of the label or labels into the female mould and simultaneous shape engagement and setting in work position also of the non adherent edges to the or the respective sucking plug end possible overlapping without deformation onto the edge of the adjacent wing. 24. A method as claimed in claim 23, for loading pre-punched labels having a central zone and side wings, which comprises withdrawing the or each label by means of one or a respective sucking plug which suction engages the central zone of each label, inserting the or each sucking plug into a pre-shaping template having a number of seats equal to and having configuration homothetic to that of the forming cavities of the female mould to be loaded, thereby bending the side wings of the or each label against the side walls of the or the respective plug, to which they adhere owing to depression, and is characterised in that it comprises - complete adhesion of only one of the edges of each pair of adjacent wings to each corner of the or each sucking plug, whereas the other edge remains slightly away from the sucking plug, - withdrawal from the pre-shaping template and transfer of the or each label in the state of incomplete adhesion to the or to the respective sucking plug, - insertion of the label or labels into the female mould and simultaneous shape engagement and setting in work position also of the non adherent edges to the or the respective sucking plug end possible overlapping without deformation onto the edge of the adjacent wing. 25. A method for loading labels into a single-female die of a machine or press for thermoforming labelled hollow objects with a bottom wall characterised in that it 5 comprises - withdrawal from a suitable label source of a number of flat labels equal in number to the forming cavities in the said female die, - transfer of the withdrawn labels to a centering or holding seat in a pre-shaping dummy die, io - three-dimensional pre-shaping of the labels centered in the dummy die by means of pre-shaping plugs, - withdrawal and transfer of the thus pre-shaped labels to the female die and simultaneous removal from the female die of the thermoformed labelled object or objects. 15 26. A method as claimed in claim 25, characterised in that the centering or holding in a correct positioning, the three-dimensional pre-configuration and removal of the pre-shaped labels occurs in a single work station. 27. A method as claimed in claim 25 or 26, characterised in that label transfer occurs by inserting the plugs each bearing a pre-shaped label between the female 20 die, on the one side, and the sheet of thermoformable material and the counter die on the other side.

Inventors: PADOVANI PIETRO, PADOVANI, PIETRO
Applicants: ISAP OMV GROUP SPA, PADOVANI PIETRO, ISAP OMV GROUP S.P.A., PADOVANI, PIETRO
Application year: 1996
Main classification: B29C51
IPC codes: B29C51