MXPA99003903A - Apparatus and method for moulding an opening device on a packaging sheet - Google Patents

Abstract

An apparatus and method for moulding opening devices (16) onto a packaging material sheet (4) at respective holes (32) provided in the sheet. The apparatus includes first and second mould tools (20, 22) arrangeable in a closed position so as to be in contact with opposite sides (24, 26) of the sheet and in an open position so as to be positioned distally from the sheet. In the closed positions a mould cavity (28) is formed between the first and second mould tools for accommodating a hole edge (30) in the sheet. The apparatus further includes an injection passage (36) for injecting heated thermoplastics material into the mould cavity, which injection passage extends in one of the mould tools such that the thermoplastics material is injected directly into the mould cavity at an injection point (38) of the mould cavity which is located distally from the hole edge, for providing effective formation of the opening device on the sheet. One of the mould tools includes a pair of half mould tools (22a, 22b) which are simultaneously moved from the open position to the closed position and vice versa such that the direction of movement of each of said half mould tools between the open and closed positions tangentially follows a circular path, for reducing wear of the mould tools. In the closed position of the mould tools, the sheet extends in a plane which is distally spaced from the plane of extension of the sheet in the open position aiding in release of the sheet and the moulded opening device from the mould tools.

Description

APPARATUS AND METHOD FOR MOLDING A DEVICE WITH OPENING ON A PACKAGING SHEET FIELD OF THE INVENTION The present invention relates to an apparatus and a method for the direct injection molding of an aperture device, of plastic material, towards an orifice provided on a sheet of packaging material. The term "device with aperture" as used herein, refers primarily to aperture devices used to empty liquid contents from a container, but also includes aperture devices that can be used to fill a container.

BACKGROUND OF THE INVENTION Devices with apertures of different types, provided on a packaging container, formed by packaging sheet material and adapted to contain substances such as food products, and in particular, are known.

REF .: 29920 to contain liquid drinks such as juices, water, milk, vLno, etc. A device with opening of this type includes a perforation on a wall part of the curling vessel and a plastic cap device coupled to the wall part, and covering the perforation in a closed state. The lid device includes a circumferential base coupled to the wall part, for example by means of adhesives, circumferentially surrounding the perforation, and a lid element hinged to the base. Once the lid element is opened, the perforation can be coupled and forced open so that the contents inside the packaging container can be dispensed therefrom. Another device with known opening includes an opening provided on a wall part of the packaging container and a lidding device of plastic material similar to one described above coupled to the wall part, and covering the opening in a closed state. A sealing element such as a pull tab, made of aluminum, is connected to the wall part, to cover the opening, and once the lid element has been opened, the sealing element can be removed to expose the opening to supply the contents of the container, packaging. The methods for providing the apertured devices described above on the packaging containers may include the feeding of continuous netting and packaging material to a first station at which the packaging is provided. perforation or opening on the network, and a second station in which the lid element is coupled to the network, to cover the perforation or opening. The pull tab, made of aluminum, if provided, for example to cover the opening, engages in an intermediate step. After the opening devices are provided on the network, packaging containers are formed from the network, filled with the product, and sealed such that the devices with opening are accommodated on the containers of finished containers, for the easy access . An example of a machine for forming, filling, and sticking out packaging containers is the TB8 filling machine, manufactured by Tetra Brik Packaging Systems of Modena, Italy. As an alternative to the opening COA devices described above, in which a device with cap of plastic material, already formed, is applied to the sheet, US Pat. No. NQ. 4,725,213 (the description of which is incorporated by reference, herein) discloses an aperture device, of plastic material, which is injection molded directly onto the sheet of packaging material. In particular, a pair of molding tools move in synchrony about a predetermined orifice in the stack and hot thermoplastic material is injected through an injection passage defined between one of the mold tools and a surface of the mold. sheet, it extends along the surface of the sheet in order to fit the device with opening in the pre-printed hole. Although the method and apparatus for providing this last type of device with aperture may be completely valid, exists in the campp of .the opening devices injected with thermoplastic material, the need for additional improvements. The injection passage in U.S. Patent No. 4,725,213 extends from the head of the injector by a significant distance a. along one surface of the sheet towards one end of the mold cavity to form the device with a ^ r u ^ a, <; to create a number of disadvantageous effects, since the passage. with injection enters the. mold cavity at one end ^ full filling of the mold cavity with the hot thermoplastic material becomes difficult and inefficient particularly in the area of the cavity of the breast accommodated distally of the injection passage. Furthermore, if the injection passage extending along a surface of the sheet is excessively long, the filling of the mold cavity becomes even more difficult and inefficient, and therefore the apparatus and the The method will be limited to molding devices with apertures accommodated substantially solp near the edge of the sheet in which it is placed, the injection head. In addition, a strip of plastic material is formed in the injection passage, and additional steps must be taken to remove such a strip, which is, therefore, inefficient and which creates the possibility of damaging the device with an aperture of from which such a strip must be removed. Additional complications arise when holding the surface of the sheet of the packaging material, which in general has a very low stiffness and resistance, to the thermoplastic material at pressures and temperatures chosen, injected into the injection passage. The difficulties described above in filling completely the mold cavity, can lead to a situation in which the plastic material will not flow to all parts of the mold cavity and as a result, the edge of the opening can, not be sufficiently sealed by the plastic material of the device with opening ^ In general, the packaging sheet material is formed of several layers including an inner paper layer and two coating layers. of plastic, synthetic, external material, one of which is intended to form a contact surface with the product. Other possible layers such as printing ink layers, lamination layers and aluminum foil layers can be interposed between the paper layer and the outer coating layers. When the opening in the packaging sheet material is stamped, the inner sheets of the packaging sheet are exposed to the edge of the embossing, and unless such an edge is properly sealed by the injected thermoplastic material opening device, the The packaged product can be contacted with the inner layers of the packaging sheet material possibly causing damage thereto. In addition, the full efficiency of the apparatus and the method are determined when the time necessary to inject the hot thermoplastic material for each molding operation is increased to ensure adequate filling of the mold cavity. The mold tools in U.S. Patent No. 4,725,213 consist of a pair of mold tools, which are both movable in directions, opening and closing, which extend perpendicularly to the extension of the sheet. Such a configuration substantially limits the flexibility of the device in the formation of devices with different shaped apertures, since the mold tools do not. they must find any portions of the device with aperture that project into. address . perpendicular to the direction d-the movement of the mold tools. The device with opening, smeared. or injection of US Patent No. 4,725,213 includes, of course, a pull tab extending in a direction perpendicular to the blade, for a long extension sufficient for being held by a user. Such a pull tab that projects extensively is disadvantageous with respect to storage, and shipping of packaging containers, including such an aperture device. It is further desired to have devices with opening with portions, base connected to the hole of the sheet and cover portions placed in planes that are slightly raised with respect to the base portions and to the packaging sheetThese portions, the lid, have an edge or projection extending parallel to the extension of the packaging door, so that they can be held and opened by a user. The apparatus of US Patent No. 4,725,213 is incapable. to form devices with this opening. type due to the opening movement of the mold tools. What is needed is an apparatus and a method for the injection molding of an opening device, made of thermoplastic material, over a sheet of packaging material that ensures that the device with the opening is molded in the most efficient way. effective and efficient as possible.

DESCRIPTION OF THE INVENTION According to a preferred aspect of the invention, there is provided a packaging machine for forming packaging containers from an actuated network of packaging sheet material, a molding station for the device with an opening for molding devices with an opening on the network. in respective holes provided in the network, whose molding station of the devices with opening includes first and second mold tools releasably. as to them in close positions to form a mold cavity, to accommodate the network's trailing edge. An injection passage for injecting hot melt thermoplastic material into the mold cavity extends in at least one of the first and second mold tools, such that the thermoplastic material is injected directly into the mold wall at an injection point. of the mold cavity, which is located distally of the edge of the hole. By having the injection point accommodated at the edge of the hole, the hot thermoplastic material advantageously enters the mold cavity in a position that allows the filling of the mold cavity is effected in an efficient and effective manner. The hot plastic material will flow from the point of injection gently and uniformly initially distally from the bprd.e of the hole and successively fill the mold cavity, so that the hot plastic material contacts the edge of the mold. hole at the end of the injection step. The times required for the injection step are therefore minimized in order to increase the efficiency of the molding operation of the opening device. In accordance with a more preferred aspect of the invention, the injection point is accommodated in a cap-forming portion of the mold cavity, and a substantially central position relative to a forming portion of the mold. The base of the old man's cavity and the injection passage extends into one of the mpl.de tools in a direction that is substantially perpendicular to the extension of the portion that forms the lid of the isolith cavity. Such configuration allows to fully maximize 1.a. efficiency of the material flow from the injection point in a symmetrical and uniform manner initially distally from the edge of the hole and successively to fill the base forming portion of the mold cavity. Such a configuration also makes it possible to completely avoid securing the network surfaces to the flow of the hot thermoplastic material. According to another preferred aspect of the invention, there is provided an apparatus for molding the device with an opening for molding devices with an opening of plastic material on a respective orifice sheet ^ provided on the sheet, which apparatus for molding the device with aperture includes first and second mold tools releasably accommodatable in perpendicular positions to form a mold cavity, to accommodate the edge of the leaf orifice, a mechanism for drive for selectively moving the first mold tool and the second mold tool between the open and closed positions, and at least one of a first and second mold tools - including a pair of half mold tools. The drive mechanism includes a support structure for supporting the mold half tools such that in the open position the mold half tools are mutually separated from one another in an extension plane extending substantially parallel to the extension plan. of the froja, and. such that in the closed position the tools of the half mold are mutually ^ arranged in contact with one another. The drive mechanism also includes an actuator to move the mold tools simultaneously from the open position to the closed position and vice versa., such that the direction of movement of each of the half-mold tools between the open and closed positions comprises a direct component extending parallel to the plane of extension of the sheet, and a directional component extending perpendicularly to the extension plane. of the sheet. With such a configuration of the drive mechanism, it is advantageously possible to directly and effectively mold dispensers with apertures of many and various shapes which can include, in particular, portions projecting and being understood in a plane that is parallel to the plane of extension of the sheet. Furthermore, the particular configuration of the drive mechanism is such that the half-mold tools reach each other and contact together in the closed position with a delicate procedure to provide minimal wear of the half-mold tools. According to a more preferred embodiment, the drive mechanism is configured such that the direction of movement of each of the half-mold tools between the open and closed positions tangentially follows a circular path, thereby minimizing the space requirements of the molding apparatus of the opening device, to minimize wear on the half-mold tools. According to still another aspect of the invention, there is provided an apparatus for molding devices with an opening, for molding with injection devices with an opening of plastic materials in holes in a sheet of packaging material, including first and second mold tools that can be adapted to open and closed positions respectively spaced apart from, and engaging with the sheet, wherein in the close position the noja extends in a plane that is distally spaced from the plane of extension of the sheet in the open position. When the blade is spaced from its normal extension by the mold tools in the closed position ,. it is placed under an added tension which advantageously facilitates the release of the sheet and the molded opening device from the mold tools such that the mold tools are moved away from the closed position to the open position, the technical characteristics and the advantages of the present invention will become apparent to those of skill in the art from the following detailed description of some preferred embodiments thereof, described and illustrated in the accompanying drawings, by way of example only. limiting, where similar reference numbers indicate similar parts.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view showing the feeding of a web of packaging sheet material into a packaging machine including a molding station of the apertured device, according to a preferred aspect of the invention; Figure 2 is a perspective view of the lower portion of a device molding station with opening, in one. first preferred embodiment of the invention; Figure 3 is a side elevational view, partly in section of the molding station of the apertured device of Figure 2, in which the mold tools are in an open position; Figure 4 is a view in lateral elevation partially in section, of the device with opening of figure 3, in which the mold tools are in a closed position; Figure 4a is an enlarged, sectional, sectional detail of the network disposed between the mold tools of Figure 4, in the closed position that forms a mold cavity ready for molding by injection of optical fibers. warm up Fig. 5 is a side elevational view partly in section of a molding station of the apertured device, in the second preferred embodiment of the invention, in which the mold tools are in an open position; Figure 6 is a side elevational view, partially in section, of the device with opening of Figure 5, in which the mold tools are in a closed position; Y Figure 6a is a detailed, sectional, enlarged view of the network positioned between the mold tools of Figure 6 in the perished position, forming a mold cavity ready for injection molding of the hot thermoplastic.

BEST MODALITIES FOR CARRYING OUT THE INVENTION With initial reference to Figure 1, an apparatus 2 according to the invention is shown, and the reference number 18 indicates a packaging machine for forming packaging containers from a network 4 of packaging sheet material. It will be understood that the apparatus 2 may be either incorporated in the packaging machine or the filling machine 18, p located upstream of such a machine. The network 4 is fed through the packaging machine 2 by means of an appropriate actuator 6a-e in a feeding direction 8. The actuator 6a ~ e is adapted to intermittently feed the sheet 4 into an intermittent feed section 2a of the machine 2, and for, to continuously feed the network 4 into a section 2b of continuous feed inwards and a section 2c of continuous feed outwards, accommodated respectively upstream and downstream of the intermittent supply septation 2a with respect to the direction 8 of network power. In the intermittent feeding septation 2a, an orifice punching station 10 is accommodated for punching holes in the network 4, and a molding station 12 for devices with an aperture for the injection molding of opening devices with thermoplastic material in the holes. provided on the network 4. The actuator 6a-e is adapted to intermittently feed the network 4 through the punching station 1Q holes such that the network 4 is properly stopped and correctly placed in the station 10 of punching holes, by a sufficient time for punching the holes in the network 4, and the appliance 6a-e is also adapted to intermittently feed the network 4 through the molding station 10 of the devices with opening, such that the holes in the network 4 are properly stopped and correctly placed in the molding station 10 of the device with opening, by a sufficient amount to moisten the devices with opening in the holes previously punched in the station 10 punching orifice. The actuator 6a-e includes the continuous feed rollers 6b and 6c respectively positioned in the inlet feed 2b segregation 2b to unwind and feed the net 4 from a reel or roll 14 of the packaging material network, and in the section -2c of continuous feeding outside, to continuously feed the network 4 with the apertured devices 16 molded thereon, to a container forming station J8, to form and seal the containers from the network 4 and Fill containers with product. The actuator 6a also includes in the intermittent feeding section a the intermittent feeding rollers 6a, the tension rollers 6d, and a idler roller 6e which together cooperate mutually to maintain the tension of the network 4 in the section 2a of intermittent feeding, substantially constant in a stopped position, so that the operations of punching and orifice and of the device with opening can be carried out with sufficient prepisión ^. In addition, the particular arrangement of the actuator 6a-e form a stop reservoir 20 for feeding h.acia inside and a reservoir 22 for feed 22 outboard. The inward feed stop reservoir 20 includes a length 4b of the inward, changing feedline extending between them. tension rollers 6d and continuous flow rollers 6b, and the neck moves vertically along the direction 20 'such that the length 4b of the feed network inwards changes in size (as indicated by the dashed lines in Figure 1) to appropriately compensate for the interface between the intermittent feed section 2a and the feed 2b section inwardly. Similarly, the reservoir of outward feed stop 22. includes a shifting feed length 4c outwardly extending between intermittent drive rollers 6a and continuous feed rolls 6c. and which moves vertically in the direction 20 'such that the length 4c of the outgoing feed network changes in size (as indicated by the broken lines in Figure 1) to properly compensate for the interface between the feeding section 2a intermittent and the feed section 2c continuously outward ^ In this way, the feed of the network 4 is continuous in the roll 14 and in the container forming station 18, while the power supply of the network 4 is intermittent in the the hole punching station 10 and in the molding station 12 of devices with aperture. In Figure 1, three hole punching stations 10 and three molding stations 12 of aperture devices are shown, such that three holes are formed in the network 4 and three devices with apertures are molded in the network 4 for each intermittent position. arrested from the network 4. The particular number of stations 10 d punching of holes and the molding stations 12 of devices cpn aperture, can vary according to requirements. In addition, the orifice punching stations 10 and the molding stations 12 of devices with opening, can move relative to each other respectively in the directions 10a and 12a along the extension of the supply of the network-4, so that the holes and aperture slides provided on the network can be relatively spaced at different positions to allow the formation of packaging containers of different sizes. The apparatus and methods for feeding the network 4, for punching holes in the network 4, and for the formation and sealing of the containers from the network 4 and the filling of the containers with product in the manner described. described above, are known, and for example, are included in the TBA / 19 system manufactured by Tetra Brik of Modena, Italy ^ The molding station 10 of the apertured devices, placed in combination with the packaging machine 2, advantageously provides a efficient and effective means for continuously molding a device with opening on a network fed from a. roll and to form, sealing and successively filling a packaging container in the same compact line, and in a continuous method. The adhesion of the devices with aperture separately formed and supplied to the network, as carried out in the conventional apparatus, is eliminated, thereby providing savings with the time and cost related to the production, storage and transportation separated from the devices put aperture separately formed .. While the molding station 10 of the devices with aperture is particularly advantageous for these reasons, it is considered that the molding cap 10 of the aperture devices, can operate in many ways different, for example for molding devices with opening on a fed network, which is then wound on a network roll for later use, or for example to mold devices with aperture on any type and shape of sheet material packaging, such as primordia of packaging material or flaps of packaging material that are projected to mention only a few. In addition, the packaging machine .2 can be provided in an alternative form, such that the roll .14 of the net is already provided with pre-stamped holes to allow the removal of the hole puncturing station 10 and / or the complete drive of the hole. network 4 is carried out intermittently. In addition, the container station 18 can be any of a number of forming stations used to form and seal containers of different sizes and shapes, and to fill different products in the containers formed. Figures 2-4a show a first preferred embodiment of the molding station 10 'of devices with an opening. The molding station of the device with aperture includes a first mold tool 20 and a second mold tool 22 which sqn which can be accommodated in relation to the network 4 in closed positions, to be on a point tp respectively on a first side 24 of the network 4 and a second side 26 of the network 4 (figures 4 and 4a), when the network 4 is n a position stopped at station 10 'of the device with opening. The first mold tool 20 and the second mold tool 22 are also adaptable with respect to the network 4 in open positions, to be placed distally respectively of the first side 24 of the network and of the second side 26 of the network (figure 3) , to allow intermittent feeding of the network 4 in the feeding direction 8. In the particular embodiment shown, the first mold tool 20 includes a simple internal mold tool 20, which operates in a fixed position, and a second tool of mold 22 including a pair of outer mold half tools 22a and 22b which are operated between the open and closed positions relative to one another, and relative to the net 4 and the internal mold tool 20, by a drive mechanism which is described later in the present. The internal mold tool 20 is accommodated for contacting the first side 24 of the net, intended to form an inner side of the packaging container formed with the net 4, while the outer mold tools 22a and 22b are accommodated for the pontaptp with the second side 26 of the net, intended to form an outer side of the packaging container formed with the net 4. With particular reference to fig. 4a, in the closed molding positions of the internal mold tool 20 and the tools of outer medium means 22a and 22b, a mold cavity 28 is formed between the internal mold tool 20 and the outer mold half tools 22a and 22b in which an edge 30 of an orifice is accommodated, of a hole 32 in the network 4 correctly positioned in the molding station 10 'of the devices with opening.

The mold cavity 28 includes in the embodiment shown a portion 28a for the formation of a lid portion of the device by "aperture 16", a portion 28b for the formation of a base portion of the device with opening 16 for connection to the the network 4 (and a connecting portion 28c for the formation of a redupidq thickness ripping edge of the device with aperture 16 to help release the cap portion of the base portion, The present disclosure relates more particularly to the In this manner, the device with opening to the net 4 is molded at the edge 30 of the hole thereof, while the opening device 16 can assume any of a number of different shapes. In the embodiment shown, the edge 30 Orifice is circumferential to completely enclose the hole in the network 4, and preferably the edge 30 of the complete hole is accommodated within the mold forming portion 28a of the mold cavity. 28, prior to injection, while the base forming portion 28b is also circumferential and has a sufficient dimension to completely enclose the edge 30 of the hole. Preferably, the edge 30 of the hole, the base forming portion 28b, and the connecting formation 28e are oval shaped in a longitudinal cross section extending substantially parallel to the extension of the network 4, and the portion 28a forming the lid which is oval-shaped, in a longitudinal cross-section extending substantially parallel to the extension of the network 4. Furthermore, in the closed molding position a free space 34 is formed between the upper mold tools and lower 20 and 22, which preferably has a width dimension smaller than the thickness of the packaging network material 4, whereby the network 4 is compressed within the free space 34, and form a seal sufficient to prevent any leakage of the hot thermoplastic material outside the mold cavity 28. The molding station 10 'of devices with aperture further includes an injection passage 36 for injecting the hot thermoplastic material into the mold cavity 28. The injection of the hot thermoplastic material through the injection passage 36 can be carried out using any conventional method and apparatus known and available to one of skill in the art. The injection passage 36 extends in the fixed internal mold.e tool 20 in the particular embodiment shown, and in accordance with a preferred aspect of the invention, the injection passage 36 is configured as such. The thermoplastic material is injected directly into the cavity 28 of the mold at an injection point 38 of the cavity 28 of the mold, which is located away from the edge 30 of the hole. By having the injection point .38. accommodated away from the boss 30 of the hole, the hot thermoplastic material advantageously enters the mold cavity in a position that allows the filling of the mold cavity to be carried out in an effective and efficient manner. The hot plastic material will flow from the injection point 38 smoothly and uniformly, initially away from the edge 30 of the hole and successively to Hen the forming portion 28b of the base of the mold cavity 28, so that the hot plastic material , make contact put the edge 30 of the hole at the end of the injection step. The times required for each injection step are minimized in order to increase the efficiency of the molding operation of the devices with opening. The injection point 38 in the particular mode./ is accommodated in the lid forming portion 28a of the mold cavity 28, in a substantially central position with respect to the base forming portion 28b. Such an arrangement allows to maximize the material flow efficiency completely from the symmetric injection point 38 and uniformly initially away from the hole edge 30 and successively to fill the shape portion 28b of the base., of the cavity 28 of the mold. In addition, the injection passage 36 extends in the internal mold tool 20, in a direction that is substantially perpendicular to the extension of the cap forming portion 28c of the mold cavity 28, to completely avoid clamping the surfaces of the mold. the network 4 to the flow of hot thermoplastic material, the internal mold tool 20 and the outer mold half tools 22a and 22b driven between the open and closed positions relative to one another, and with respect to the network and a. the internal mold tool 20, by means of a drive mechanism 40. The drive mechanism 4.0 is poordinadq with the actuator 6a-e to feed the network 4, with the station d punching holes, and with the injection of the hot thermoplastic material to through the injection passage 36, to provide a continuous production of devices with aperture 16, molded, over the network. 4. The drive mechanism 40 includes a frame structure 42 for supporting the outer mold half tools 22a and 22b, such that in the open position the outer mold half tools 22a and 22b are mutually spaced from one another in an extension plane extending substantially parallel to the extension plane of the network 4 (Figure 3) and such that in the closed position the outer mold half tools 22a and 22b are mutually accommodated in contact with each other and with the second side 26 of the network (figures 4-4a). The drive mechanism 40 also includes an actuator 44 for moving the outer mold half tools 22a and 22b from the open position to the closed position and vice versa - such that the direction of movement of each of the outer mold half tools between the open and closed pospions, includes a directional component that extends parallel to the extension plane of the network 4 and a directional component that extends perpendicularly to the extension plane of the network 4. The particular configuration of the drive mechanism 40, the which moves the outer mold half tools 22a and 22b in directions such that they move between the open and closed positions, allows to advantageously form the devices with aperture in many varied forms, which can include in particular portions that they are projected and that they extend in a plane that is parallel to the extension plane of network 4. Ad moreover, the particular configuration of the drive mechanism 40 is such that the half-mold tools 22a and 22b mutually reach and contact each other in the closed position with a delicate procedure, since the movement of each of the outer mold half tools 22a and 22b can implement a directional component parallel to the extension plane of the network 4 / which is minimized while achieving mutual contact in the closed position. Such a delicate process of the outer mold half tools 22a and 22b advantageously provides minimal wear of the outer mold half tools 22a and 22b. In a more preferred embodiment as shown in Figures 2-4, the drive mechanism 40 is configured such that the direction of movement of each of the outer mold half tools 22a and 22b between the open and closed positions follows tangentially a circular trajectory. In this way, the directional movement component, parallel to the extension plane of the network 4 of the outer mold half tools 22a and 22b in the approach and release phases closest to the closed position, can be minimized virtually at zero while such a directional movement component parallel to the extension plane of the network 4 in phases away from the closed position, can be rapidly increased, to minimize the space requirements of the molding station 10 'of the device with aperture, and to minimize wear on the outer mold half tools 22a and 22b, while maintaining flexibility with respect to forming aperture devices in different ways. The support structure 42 includes a structure. of fixed support having a horizontal base 46 and pairs of arms 48a-c extending vertically in an upward direction from the base 42. The support structure further includes a pair of levers 50 and 52 that freely pivot respectively between the pairs of side arms 48a and 48c and the outer mold half tools 22a and, 22b about the pivot shafts, 1QS which extend substantially parallel to the extension plane of the network 4. The support structure 42 further includes a plate horizontal slide 54 having slots 54a in which the bolts 54b connected to each of the outer mold half tools 22a and 22b are slidably accommodated. The slots 54a extend in the sliding plate 54 such that each μna of the outer half-mold tools 22a and 22b are slidably supported on the sliding plate 54., in a linear direction extending parallel to the feeding direction 8 of the net.

The actuator. 44 includes a fluid-operated cylinder 55 having a rod that slidably extends through the fixed base 46 and connected to the sliding plate 54 for alternating movement of the sliding plate 54 in a vertical direction extending perpendicularly to the extension of the network 4., JSs particular configuration of the drive mechanism 40 causes the outer mold half tools 22a and 22b to move between the open and closed positions along a circular path centered about the pivot axes respectively of the pawl pairs 50 and 52 and the side arms 48a and 48c. The dimensions of media tools , outer mold 22a and 22b, side arms 48a and 48c, and lever pairs 50 and 52 are such that when the tools • of outer mold half 22a and 22b are accommodated in contact in the closed position, a contact force between the mating surfaces of the outer mold half tools 22a and 22b is created sufficiently to provide an adequate seal of the mold cavity 28, such that the thermoplastic material hot will not leak excessively out of the cavity 28 of the mold, at the site of the coupling surfaces d the outer medial means 22a and 22b. According to a further aspect of the invention, an adjustable biasing device is provided to adjustably establish the contact force between the outer mold means 22a and 22b in the closed position. For this purpose, the lateral arms 48a and 48c are provided. with empty spaces 56 from side to side, the. which make the side arms 48a and 48c relatively flexible in a direction parallel to the feed direction 8 of the network, and a pair of tension rods 58 are interconnected between the side arms 48a and 48c. The tension rods 58 are freely slidably placed in the central arms 48b, and the adjusting nuts 58a are tightly screwed into the ends of the tension rods 58. • Figure 4 illustrates the outward bending of the side arms 48a and 48c when the outer mold half tools 22a and 22b are in the closed coupling position, and the adjustment of the nuts 58a will suitably select the desired contact force between the outer mold half tools 22a, and 22b in the closed position. The configuration of the support structure 42 is such that in the closed position the outer molding means.e tools 22a and 22b (Fig. 4), the portion of the net 4 contacting the outer mold half tools 22a and. 22b, extends in a plane that is distally separated from the normal plane of extension of the net 4 in the open position of the outer mold half tools 22a and 22b (Figure 3). In this way, the network 4 in the spaced position of its normal extension is placed under an aggregate tension which advantageously facilitates the release of the network 4 and the device with opening 16, molded, from the mold tools 20 and 22, such that the mold tools 20 and 22 move away from the closed position towards the open position. Figures 5-6a show a second, preferred embodiment of the molding station 10"of the apertured device, the molding station 10" of the apertured device includes a first mold tool 20 '.and a second mold tool 22'. , which are adaptable with respect to the network 4 in closed positions to be in contact respectively with a first side 24 of the rd 4 and μn second side 26 of the network 4 (Fig. 6 and 6a), when the network 4 is in a stopped position in the molding station 10"of the device with opening The first mold tool 20 'and the second mold tool 22' are also accommodatable with respect to the network 4 in open positions, to be placed distally respectively of the first side 24 of the network and the second ladp 26 of the network (Figure 5), to allow intermittent feeding of the network 4 in the feeding direction 8. The first mold tool 20 'includes a simple internal mold tool 20', movable in a vertical direction, and the second mold tool 22 'includes a pair of lateral outer mold tools 22a '22b', each movable in the vertical direction and in the horizontal direction. The internal mold tool 20 'and the lateral external mold tools 22a' and 22b 'are driven between the open and closed positions one relative to the other, and with respect to the network 4, by means of a driving mechanism the as described later herein, With reference to Figure 6a, a mold cavity 28 'is formed in the closed molding positions of the internal mold tool 20' and the lateral outer mold tools 22a 'and 22b'. between the internal mold tool 20 'and the lateral outer mold tools 22a and 22b in which the edge 30 of the hole 32 is accommodated in the network 4, correctly positioned in the molding station 10"of the opening device, the cavity 28 'of the mold includes a portion 28a' for the formation of a lid portion of the device with opening 16, a portion 28b 'for the formation of a base portion of the device with opening 16 for connection to the network 4, and a portion of connection 28c 'for the formation of a tear edge, of reduced thickness of the device with opening 16, to assist in the release of the capped portion from the base portion. The full hole edge 30 is preferably accommodated within the base forming portion 28a ', prior to injection, while the base forming portion 28b' is circumferential and has a sufficient dimension to completely enclose it. the edge 30 of the hole. Preferably, the base forming portion 28b 'and the connecting portion 28c' are oval shaped in a longitudinal cross section extending substantially parallel to the extension of the network 4, and the porous forming portion 28a ' the lid is oval shaped in a longitudinal cross section extending substantially parallel to the extension of the net 4. Moreover, in the closed molding position a free space 34 'is formed between the upper and lower mold tools. 'and 22', which preferably has a dimension of width s small than the thickness of the packaging network material 4, whereby the network 4 is compressed within the free space 34 ', and form a sufficient seal to prevent any doubt of the hot thermoplastic material outside the cavity 28 'of the mold. The molding station 10"of the apertured device further includes an injection passage 36 'for injecting hot thermoplastic material into the mold cavity 28' The injection passage 36 'extends in a fixed injection head 60 which has a top end portion 60a forming part of the second mold tool 22 ', as seen in Figure 6a.As a consequence, the lateral outer mold tools 22a' and 22b 'are moveably accommodatable with respect to the end portion fixed top 60a, in the closed-molding position, forming the mold cavity 28 'The injection passage 36' is configured such that the thermoplastic material is injected directly into the mold cavity 28 'at an injection point 38' of the cavity 28 'of the mold ^ which is located away from the edge 30 of the hole, so that the advantageous effects are achieved as are obtained by the first embodiment described above of the Mold station 10 'of the device with opening. The injection passage 36 'further extends in the outer mold tool 22' in a direction that is substantially perpendicular to the extension of the cap-forming portion 28c ', from the mold cavity 28', distally of the surfaces of the mold. the network 4. The drive mechanism for driving the internal mold tool 20 'and the lateral outer mold tools 22a' and 22b 'which are between the open and closed positions, include a movable support structure 62, circumferentially accommodated about the fixed injection head 60 and movable in a vertical direction, and a fixed support structure 64 supporting the fluid-activated cylinders 60a-b and 68, which have ßßa rods 'b' and 68 ', respectively connected to the movable support structure 62 and the internal mold tool 20', for the alternating movement of these elements in the vertical direction, the actuating mechanism further includes the cylinders 70a and 70b fluid activated having rods 70a 'and 70b' respectively connected to the lateral outer mold tools 2,2a 'and 22Jo' for the alternating movement of these elements in the horizontal direction. The drive d.e. cylinders 66a-b, 68 and 70a-b is coordinated with the actuator 60a-e to feed the network 4, with the station 10 for punching holes, and with the injection of the hot thermoplastic material through the injection passage 36 ', to provide a continuous production of devices with opening 16, molded, on the network 4.

It is noted that in relation to this roof, the best method known by the applicant to carry out the cited invention is that which is clear from the present description of the invention.

Claims (14)

CLAIMS Having described the invention as above, it is claimed as property contained in the following claims:

1. An apparatus for molding devices with aperture, for injection molding devices with aperture, of plastic material, in holes in a sheet of packaging material, characterized in that the apparatus comprises: at least one first mold tool accommodatable in a closed position, for being in contact with a first side of the sheet placed in the molding station of the devices with opening, and accommodating in an open position to be polored away from the first side of the sheet placed in the molding station of the devices.; at least one second mold tool accommodatable in a closed position to be in contact with a second side of the sheet placed in the station. molding the device with opening, and accommodating in an open position to be placed away from the second side of the sheet placed in the opening station of devices with opening; wherein in the closed positions of the first and second mold tools, a mold cavity is formed between the first and second mold tools to at least partially accommodate an orifice edge in the sheet placed in the molding station of the devices with opening;, and an injection passage for injecting hot thermoplastic material into the mold cavity, wherein the injection passage extends in at least one of the first and second mold tools, such as the thermoplastic material. is injected directly into the mold cavity at an injection point of the mold cavity, which is located away from the edge of the hole, accommodated in the mold cavity.

2. The apparatus according to claim%, characterized in that the cavity of the mold has a base portion to accommodate the edge of the hole in the closed positions of the first and second mold tools, and for the formation of a base of an opening device. , molded, and a portion d cap to form a lid of the device with aperture, molding.

3. . The apparatus according to claim 1, characterized in that the injection point of the mold cavity is accommodated in the lid portion in a substantially central position with respect to the base portion.

4. The apparatus according to claim. 3,. characterized in that the injection channel extends substantially perpendicular to the extension of the lid portion of the mold cavity.

5. The apparatus according to claim 1, further comprising a drive mechanism for selectively moving the first mold tool and the second mold tool between the open and closed positions, at least one of the first and second mold tools comprise a pair of half mold tools, characterized the drive mechanism because it comprises: a support structure, to support the tools < The mold half is such that in the open position the half-mold tools are mutually spaced from one another in an extension plane extending substantially parallel to the plane of extension of the sheet, and such that in the closed position the half-mold tools are mutually accommodated with each other and with the second side of the sheet; and μn actuator for moving the mold half tools substantially from the open position to the closed position and vice versa, such that the direction of movement of each of the mold half tools between the open and closed positions comprises a directional component which is extends parallel to the extension plane, and a directional component that extends perpendicular to the extension plane.

6. The compliance device set forth claim 5, characterized in that the drive mechanism is configured such that the direction of movement of each of the half-mold tools, between the open and perpendicular positions, follows a circular path tangentially.

7. The apparatus according to claim 5, characterized in that in the closed position the blade extends in a plane which is distally spaced from the plane of extension of the blade in the open position.

8. The apparatus according to claim 5, characterized in that it further comprises an adjustable deflection device, to establish adjustably a contact force between the ^. half mold tools in the closed position.

9. A method for direct injection molding of u? device with opening, of plastic material, to a prifipiq that is placed on a sheet of packaging material, and which has an edge of the hole, the method is characterized in that it comprises the steps of: accommodating at least one first tool of mold in contact with a first side of the packaging sheet material, and accommodating at least one second mold tool in contact with a second side of the packaging sheet material, and thereby forming a mold cavity defined between the first and second mqlde tools in a manner such that at least a portion of the edge of the hole is accommodated within the mold cavity; and injecting plastic material into the mold cavity, to form the apertured device, of plastic material, wherein the plastic material is injected directly into the mold cavity at an injection point of the mold cavity. , which is located away from the edge portion of the hole.

10. The method according to claim 11, characterized in that it includes the accommodation of the first and second mold tools to form a mold cavity having a base portion, to form a base of the opening device and a lid portion, for forming a lid of the opening device, in such a way that the entire edge of the hole is accommodated within the base portion of the mold cavity.

11. The method according to claim 10, characterized in that it includes the injection of plastic material at an injection point accommodated in the lid portion of the mold cavity, in a substantially central position with respect to the edge of the hole.

12. . E.1 method according to claim 11, characterized in that it includes the injection of plastic material through the injection channel, which is deposited in one of the first and second mold tools, and the Qual extends substantially perpendicular to the extension of the lid portion of the mold cavity.

13. An aperture device, made of plastic material, characterized in that it is obtained by a method for the direct injection molding of a plastic material opening device, as defined in accordance with one or more of claims 9 to 12.

14. A container for volatile food products, characterized in that it comprises an opening device, made of plastic material, obtained by the method as defined in accordance with a q. more of claims 9 to 12. SUMMARY OF THE INVENTION An apparatus and a method for molding aperture devices (16) on a sheet (4) of packaging material in the respective holes (32) provided by the sheet is described. The apparatus includes first and second mold tools (20, 22). ) accommodated in a perished position, to be in contact with the opposite sides (24, 26) of the blade, and in an open position to be positioned distally of the blade. In the closed positions a mold cavity 4e (28) is formed between the first and second mold tools, to accommodate a rim (30) in the sheet. The apparatus further includes an injection passage (36) for injecting hot thermoplastic material into the mold cavity, which injection passage extends into one of the mold tools such that the thermoplastic material is injected directly into the mold cavity. at an injection point (38) of the mold cavity, which is positioned distally of the edge of the qrificiq, to provide effective formation of the device with opening on the sheet. One of the mold tools includes a pair of half-mold tools (22a, 22b), which are simultaneously moved from the open position to the closed position and vice versa, such that the direction of movement of one of. the half-mold tools between the open positions and the tangentially follows one. circular path, to reduce the wear of tools, mold, _ In the closed position of the mold tools, the sheet extends in a plane that is distally spaced from the plane of extension of the sheet in the open posipión, helping the release of the tqj ay of the device, with opening, molding, from the mold tools.