Device for blow-molding containers

Abstract

A device (1) for blow-molding containers (10), which comprises a supporting frame for at least one blow-molding station (3) which comprises two lateral bodies (3a, 3b) and a bottom, each lateral body (3a, 3b) being associated with a respective mold part (4a, 4b), the mold parts (4a, 4b) being configured to form, when mutually adjacent, at least one blow-molding cavity for blow-molding at least one container (10), the lateral bodies (3a, 3b) being movable on command by way of cyclic opening and closing means (20) about an axis of articulation (101) defined at an interconnection shaft (5), the latter means being configured to move the blow-molding station (3) between an open condition, in which the lateral bodies (3a, 3b) are mutually angularly spaced apart around the axis of articulation (101), and a closed condition, in which the respective mold parts (4a, 4b) are mutually mated to form the molding cavity or cavities, each lateral body (3a, 3b) having at least one respective mating edge (11, 12), the latter edges being designed, in the closed condition of the blow-molding station (3), to be mutually mated in order to allow, during blow-molding operations, the mold parts (4a, 4b) to be locked together, the blow-molding station (3) comprising means for mutual locking (30) between the mating edges (11, 12) of the lateral bodies (3a, 3b) in a mutually-mated condition; the means for mutual locking (30) are arranged substantially at the neutral plane (200) of the portion of the lateral bodies (3a, 3b) that is located at the respective mutually-mated mating edges (11, 12).

Description

[0001] DEVICE FOR BLOW-MOLDING CONTAINERS

[0002] The present invention relates to a device for blow-molding plastic containers, and in particular made of PET, PE, PEN and similar materials.

[0003] Plants are known for blow-molding plastic containers which comprise an apparatus for blow-molding preforms, consisting of blow-molding stations arranged on rotating advancement wheels and with the mold support pivoted in the manner of a book.

[0004] The execution of the movements to open and close the blow-molding station, as well as the execution of the movements to lift the base portion (or bottom), is usually actuated mechanically.

[0005] In blow-molding stations arranged on rotating advancement wheels, in particular, curved segments (cams) are arranged fixed on the chassis of the machine, along which tappet rollers are conducted, which are connected with the elements to be moved.

[0006] EP 3380300B1 describes a device for blow-molding containers that has a supporting frame for at least one station for blow-molding preforms in order to obtain containers.

[0007] The blow-molding station comprises two lateral bodies and a bottom, which are adapted to provide, by blow-molding, at least one container; at least one of the two lateral bodies can be moved on command, with respect to the supporting frame, about an axis of articulation by means of cyclic opening and closing means.

[0008] The device in question has kinematic connection means between the movable lateral body and the bottom, which are adapted to cyclically produce the movement of the bottom along a movement direction that is substantially parallel to the axis of articulation.

[0009] The cyclic opening and closing means comprise an actuation body which is supported by a link rod, which can be moved with respect to the supporting frame about a pivoting axis which is substantially parallel to the axis of articulation; the link rod is kinematically connected to the movable lateral body and is rotatably associated with a contoured body that can be moved along a straight trajectory, defining a cam-like profile that can be engaged by an engagement element supported by the bottom.

[0010] In many applications, if both lateral bodies of the mold are moved, then the axis of articulation is arranged toward the carousel axis, farther away than the pitch circle.

[0011] Such an implementation choice means that, in order to ensure a sufficiently large opening to feed the preform and remove the container into / out of the mold, the movable lateral bodies of the mold in the open condition need to have a considerable bulk.

[0012] Furthermore, the known solutions do not allow optimization of the movement to open and close the movable lateral bodies.

[0013] Furthermore, by locating the axis of articulation away from the lateral bodies, the stresses acting on the parts of the mold are quite high and this results in increased cross- sections of the various components and, as a consequence, an increased overall bulk.

[0014] The aim of the present invention is to provide a device for blowmolding containers that is capable of improving the known art in one or more of the above-mentioned aspects.

[0015] Within this aim, an object of the invention is to make available a device for blow-molding containers that reduces the overall bulk and avoids excessive stresses on the moving parts.

[0016] Another object of the invention is to provide a device for blowmolding containers that enables a high flexibility of operation, by offering the option to regulate the movements to open and close the molds.

[0017] Another object of the invention is to provide a device for blowmolding containers that is highly reliable, easy to implement, and at low cost.

[0018] This aim and these and other objects which will become better apparent hereinafter are achieved by a device for blow-molding containers according to claim 1, optionally provided with one or more of the characteristics of the dependent claims.

[0019] Further characteristics and advantages of the invention will become more apparent from the description of some preferred, but not exclusive, embodiments of the device for blow-molding containers according to the invention, which are illustrated for the purposes of non-limiting example in the accompanying drawings wherein:

[0020] Figure 1 is a perspective view of a blow-molding station according to the invention in the open condition;

[0021] Figure 2 is a perspective view of a blow-molding station according to the invention in the closed condition;

[0022] Figure 3 is a view from above of the blow-molding station in the open condition;

[0023] Figure 4 is a view from above of the blow-molding station in the closed condition;

[0024] Figure 5 is a side view of the closed blow-molding station with open latches;

[0025] Figure 6 is a side view of the closed blow-molding station with closed latches;

[0026] Figure 7 is a detail of a portion of the blow-molding station of Figure 5;

[0027] Figure 8 is a view similar to that of Figure 1 but showing the molded container inside the blow-molding station, part of the supporting structure, the bottom assembly, and the kinematic command system;

[0028] Figure 9 is a cross-sectional view of the blow-molding station in the open condition, taken along a horizontal plane;

[0029] Figure 10 is a cross-sectional view similar to that of Figure 9 with the blow-molding station in the closed condition;

[0030] Figure 11 is a perspective view of the cyclic opening and closing means; Figure 12 shows the driving shaft of the cyclic opening and closing means;

[0031] Figure 13 is a view similar to that of Figure 1 of another embodiment of the blow-molding station according to the invention.

[0032] With reference to the figures, the present invention relates to a device for blow-molding containers, generally designated by the reference numeral 1 , which has a supporting frame for at least one blow-molding station 3 for blow molding preforms in order to obtain containers 10.

[0033] The blow-molding station 3 comprises two lateral bodies 3a, 3b, also called mold-holders, and a bottom.

[0034] Each lateral body 3a, 3b is associated with a respective mold part 4a, 4b, and, when placed close together, they are configured to define at least one blow-molding cavity for blow molding at least one container 10.

[0035] The two lateral bodies 3a, 3b are movable on command by means of cyclic opening and closing means 20 about an axis of articulation 101 which is substantially parallel to the axis of the at least one container 10 to be produced.

[0036] The axis of articulation 101 is defined at an interconnection shaft 5 about which respective coupling elements 5a, 5b can rotate, the latter coupling elements being integral in rotation, about the axis of articulation 101, with respective lateral bodies 3a, 3b.

[0037] The cyclic opening and closing means 20 are configured to move the blow-molding station 3 between an open condition, in which the lateral bodies 3a, 3b and, as a consequence, the respective mold parts 4a, 4b are mutually angularly spaced apart around the axis of articulation 101 in order to define an access opening for loading the preform into the mold and removing the container from the mold, and a closed condition, in which the respective mold parts 4a, 4b are brought together and coupled in order to define the molding cavity or cavities.

[0038] Each lateral body 3a, 3b has at least one respective mating edge 11, 12.

[0039] The mating edges 11, 12 of each lateral body 3a, 3b are designed, in the closed condition of the blow-molding station 3, to be mutually mated in order to allow, during the blow-molding operations, the mold parts 4a, 4b to be locked together.

[0040] The blow-molding station 3 comprises means for mutual locking 30 between the mating edges 11, 12 of the lateral bodies 3a, 3b in the mutually mated condition.

[0041] The means for mutual locking 30 are arranged substantially at the neutral plane 200 of the portion of the lateral bodies 3a, 3b that is located at the mutually mated respective mating edges 11, 12.

[0042] The term "neutral plane" 200 means the location of the points at which the bending tensions owing to the action of the stress forces, in this case acting during the step of molding, are equal to zero.

[0043] In this case, the term "neutral plane" does not mean a perfectly flat surface, but rather a curved surface that follows, substantially, the curvilinear extension of the lateral bodies 3a, 3b.

[0044] According to the embodiment shown in the figures, one of the lateral bodies, indicated in the figures with the reference numeral 3a, has a first and a second mating edge I la, 11b which are configured to be mutually mated respectively with a first and a second mating edge 12a, 12b of the other lateral body 3b.

[0045] Conveniently, the mating edges 11, 12 are arranged, when the blowmolding station 3 is in the closed condition, along a diametrical plane 201 of the mold.

[0046] Advantageously, the means for mutual locking 30 between the mating edges 11, 12 of the lateral bodies 3a, 3b in the mutually-mated condition comprises first means for mutual locking 31 which act between the first mating edges I la, 12a and second means for mutual locking 32 which act between the second mating edges 11b, 12b. Both the first means for mutual locking 31 and the second means for mutual locking 32 are arranged substantially at the neutral plane 200 of the portion of the lateral bodies 3a, 3b located at the respective mutually-mated mating edges 11, 12.

[0047] This embodiment makes it possible to minimize the stresses due to blow-molding operations on the lateral bodies 3a, 3b.

[0048] With reference to the embodiment shown in the figures, the first means for mutual locking 31 are arranged on the outward-facing side of the blow-molding station 3, while the second means for mutual locking 32 are arranged on the inward-facing side of the blow-molding station 3.

[0049] The outward-facing side is the part of the blow-molding station 3 where the preforms are fed in and the containers 10 are removed, while the inward-facing side is the part arranged proximate to, or at, the axis of articulation 101.

[0050] If, as is usual, the blow-molding stations 3 are mounted at the periphery of a carousel structure, then the outward-facing side corresponds to the outer side, while the inward-facing side is the side facing toward the axis of rotation of the carousel.

[0051] In the embodiment illustrated, the axis of articulation 101 is arranged externally to the lateral bodies 3a, 3b proximate to the second means for mutual locking 32.

[0052] Alternatively, it is possible for the blow-molding station 3 to have exclusively the first means for mutual locking 31 on the outward-facing side of the blow-molding station 3, while the interconnection shaft 5 which defines the axis of articulation 101 is positioned in a diametrically opposite position, between the second mating edges 11b, 12b.

[0053] In this case, the interconnection shaft 5 between the lateral bodies 3a and 3b is arranged at the neutral plane 200.

[0054] According to a preferred practical embodiment, the means for mutual locking 30 comprise at least one latch, and in particular at least one elongated latch-like body 36, which is supported by one of the lateral bodies (in the figures the lateral body 3b) and is arranged with its main axis of extension 301 substantially parallel to the axis of articulation 101 and is movable on command along a movement direction, indicated by the arrows 302, which is parallel to its own main direction of extension 301.

[0055] The elongated latch-like body 36 has, along its main direction of extension 301, at least one locking head 37 configured to engage, following the movement of the elongated latch-like body 36 along a first orientation 302a of the movement direction 302, a respective locking seat 38 defined on the other lateral body 3a.

[0056] Preferably, the elongated latch-like body 36 has a plurality of locking heads 37 which are mutually spaced apart along the main direction of extension 301; similarly, a plurality of locking seats 38 are defined on the other lateral body 3a which are also spaced apart from each other, correspondingly to the distance between the locking heads 37, along a direction of extension.

[0057] Each locking seat 38 is designed to be engaged by a respective locking head 37 following the movement of the elongated latch-like body 36.

[0058] The one or more locking heads 37 have a respective mating surface 37a which is configured to engage so that it can slide, during the movement of the elongated latch-like body 36 along the first orientation 302a, with a complementarily-shaped surface 38a defined on the respective locking seat 38 and directed toward the respective mating surface 37a.

[0059] The mating surface 37a lies on an inclined plane shaped like a wedge with the apex pointed in the same direction as the first orientation 302a of movement, so that the movement of the elongated latch-like body 36 in the first orientation 302a, with the mating edges 11 and 12 in mutual contact, can determine a mutual clamping between the lateral bodies that is capable of counteracting their being pulled apart during blow-molding operations. Preferably, the lateral body 3b that supports the elongated latch-like body 36 is associated with an actuation system 41, typically a pneumatic cylinder 41a, for moving a toggle structure 42 which comprises a first lever system 43 and a pusher element 44.

[0060] The lever system 43 is supported so that it can rotate, at a first end, by a supporting footing 46 connected to the lateral body 3b, and is connected at the opposite end to the actuation system 41, while the pusher element 44 is hinged, at one end thereof, to an intermediate region of the lever system 43 and, at the opposite end, to the elongated latch-like body 36 so that the actuation system 41 can command the elongated latch-like body 36 to move in a first orientation 302a of the movement direction in order to clamp the respective mating edges 11 and 12 together, and in the opposite orientation 302b in order to move the respective mating edges 11 and 12 apart and consequently bring the blow-molding station 3 to the open condition.

[0061] According to a further aspect of the present invention, the movable lateral bodies 3a and 3b are commanded, in their rotation about the axis of articulation 101, by the cyclic opening and closing means 20.

[0062] With reference to the embodiment shown in the figures, the cyclic opening and closing means 20 comprise an electric actuation system motor 21 with an actuation shaft 22 arranged with its axis of rotation 102 parallel to the axis of articulation 101.

[0063] The actuation shaft 22 is connected kinematically, by way of respective kinematic connection means 23, to the movable lateral bodies 3a and 3b so that the rotation of the actuation shaft 22 about its own axis of rotation 102 determines the rotation of the movable lateral bodies 3a and 3b about the axis of articulation 101.

[0064] In particular, the actuation shaft 22 comprises a crankshaft 22a, associated with a first and with a second command linkage 23a and 23b for kinematic connection to a respective movable lateral body 3 a and 3b.

[0065] In particular, each command linkage 23 a, 23b is connected to a respective interconnection body 24a, 24b which connects the interconnection shaft 5 with the movable lateral bodies 3a and 3b.

[0066] The command linkages are pivoted, and therefore rotatable, at their longitudinal ends, to the crankshaft 22a and to the respective interconnection bodies 24a and 24b.

[0067] This embodiment makes it possible to convert the rotary motion of the crankshaft 22a about its own axis of rotation 102 to an oscillating motion of the interconnection bodies 24a and 24b about the axis of articulation 101.

[0068] This embodiment makes it possible to cyclically open the mold parts 4a and 4b by rotating the actuation shaft 22.

[0069] Furthermore, by acting on the rotation of the shaft 22, it is possible to intervene on the width of the opening of the bodies 3 a and 3b.

[0070] With reference to what is shown in Figure 13, it is possible for the supporting footing 46, at least in a part of it, to be connected to the respective movable lateral body, in this case the lateral body 3b, by way of elastic compensation means 45 which make it possible to make the kinematic assembly less rigid so as to compensate for any tolerances.

[0071] The operation of the device 1 according to the invention is the following.

[0072] When it is in the open condition, the blow-molding station 3 is fed with the preforms to be blow-molded by conventional feeding devices.

[0073] At this point, once the preform or preforms are accommodated inside the mold parts 4a and 4b, the cyclic opening and closing means 20, constituted for example by the crankshaft 22a, command the rotation of the movable lateral bodies 3a and 3b in order to make them rotate about the axis of articulation 101 so as to bring the respective lateral bodies mutually close and bring the blow-molding station 3 to the closed condition.

[0074] Once the respective mating edges 11 and 12 of the lateral bodies 3 a and 3b are in mutual contact, the means for mutual locking 30 are actuated by means of the movement, by the toggle structure 42, of the elongated latch-like body 36 which is moved along the first orientation 302a of movement so as to engage the locking heads 37 in the respective locking seats 38.

[0075] The means for mutual locking 30, arranged at the neutral planes 200, make it possible to minimize stresses, so making it possible to reduce the dimensions and the cross- sections of such means for mutual locking 30 and of the lateral bodies 3a and 3b taken as a whole.

[0076] In the closed condition, and with the means for mutual locking 30 activated, the blow-molding of the preform is executed so as to obtain the container 10.

[0077] Once the blow-molding operations are concluded, the means for mutual locking 30 are deactivated by moving the elongated latch-like body 36 along the orientation 302b of the movement direction 302, so as to allow the lateral bodies 3a and 3b to be opened up in order to allow the blow- molded container 10 to be removed.

[0078] In practice it has been found that the invention fully achieves the intended aim and objects by providing a device that offers a limited bulk in that it is subjected to greatly reduced stresses on moving parts.

[0079] Furthermore, by virtue of the structure of the means for mutual locking 30, it is possible to avoid the use of high-pressure compensation means between the lateral bodies 3a and 3b and the respective mold parts 4a and 4b, with evident savings in terms of cost and, especially, of energy during operation.

[0080] The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims. Moreover, all the details may be substituted by other, technically equivalent elements.

[0081] In practice the materials employed, provided they are compatible with the specific use, and the contingent dimensions and shapes, may be any according to requirements and to the state of the art. The disclosures in Italian Patent Application No. 102024000003490 from which this application claims priority are incorporated herein by reference.

[0082] Where technical features mentioned in any claim are followed by reference signs, such reference signs have been inserted for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

CLAIMS1. A device (1) for blow-molding containers (10), which comprises a supporting frame for at least one blow-molding station (3), said blowmolding station (3) comprising two lateral bodies (3a, 3b) and a bottom, each lateral body (3a, 3b) being associated with a respective mold part (4a, 4b), said mold parts (4a, 4b) being configured to form, when mutually adjacent, at least one blow-molding cavity for blow-molding at least one container (10), said lateral bodies (3a, 3b) being movable on command by way of cyclic opening and closing means (20) about an axis of articulation (101) defined at an interconnection shaft (5), said cyclic opening and closing means (20) being configured to move said blow-molding station (3) between an open condition, in which said lateral bodies (3a, 3b) are mutually angularly spaced apart around said axis of articulation (101) in order to define an access opening for loading the preform(s) and for removing at least one container (10) from the mold, and a closed condition, in which the respective mold parts (4a, 4b) are mutually mated to form the molding cavity or cavities, each lateral body (3a, 3b) having at least one respective mating edge (11, 12), the mating edges (11, 12) of each lateral body (3 a, 3b) being designed, in the closed condition of the blow-molding station (3), to be mutually mated in order to allow, during blow-molding operations, the mold parts (4a, 4b) to be locked together, said blow-molding station (3) comprising means for mutual locking (30) between the mating edges (11, 12) of the lateral bodies (3a, 3b) in a mutually -mated condition, characterized in that said means for mutual locking (30) are arranged substantially at the neutral plane (200) of the portion of the lateral bodies (3a, 3b) that is located at the respective mutually-mated mating edges (11, 12).

2. The device (1) according to claim 1, characterized in that one of the lateral bodies (3a) has a first and a second mating edge (I la, 11b), which are configured to be mutually mated with a first and a second mating edge(12a, 12b) of the other lateral body (3b), the means for mutual locking (30) between the mating edges (11, 12) of the lateral bodies (3a, 3b) in a mutually-mated condition comprising first means for mutual locking (31) acting between the first mating edges (I la, 12a) and second means for mutual locking (32) acting between the second mating edges (11b, 12b), said first means for mutual locking (31) and said second means for mutual locking (32) being arranged substantially at the neutral plane (200) of the portion of the lateral bodies (3 a, 3b) located at the respective mutually- mated mating edges (11, 12).

3. The device (1) according to claim 1, characterized in that said mating edges (11, 12) are arranged, when the blow-molding station (3) is in the closed condition, along a diametrical plane (201) of the mold.

4. The device (1) according to claim 2, characterized in that said first means for mutual locking (31) are arranged on an outward-facing side of said blow-molding station (3), and in that said second means for mutual locking (32) are arranged on an inward-facing side of said blow-molding station (3), said axis of articulation (101) being arranged externally to said lateral bodies (3a, 3b) proximate to said second means for mutual locking (32).

5. The device (1) according to one or more of the preceding claims, characterized in that said blow-molding station (3) comprises said first means for mutual locking (31) on the outward-facing side of said blowmolding station (3), said interconnection shaft (5) which defines said axis of articulation (101) being positioned in a diametrically opposite position, between said second mating edges (11b, 12b), said interconnection shaft (5) between said lateral bodies (3a, 3b) being arranged at the neutral plane (200).

6. The device (1) according to one or more of the preceding claims, characterized in that said means for mutual locking (30) comprise an elongated latch-like body (36) which is supported by one of said lateralbodies (3a, 3b) and is arranged with its main axis of extension (301) substantially parallel to said axis of articulation (101), said latch-like elongated body (36) being movable on command along a movement direction (302) which is parallel to its own main direction of extension (301).

7. The device (1) according to one or more of the preceding claims, characterized in that said elongated latch-like body (36) has, along its main direction of extension (301), at least one locking head (37) configured to engage, following the movement of said elongated latch-like body (36) along a first orientation (302a) of the movement direction (302), a respective locking seat (38) defined on the other lateral body (3b).

8. The device (1) according to one or more of the preceding claims, characterized in that said elongated latch-like body (36) has a plurality of locking heads (37) which are mutually spaced apart along said main direction of extension (301), a plurality of locking seats (38) being defined on the other lateral body (3b) which are also spaced apart from each other along a direction of extension and are designed to be engaged by a respective locking head (37) following the movement of said elongated latch-shaped body (36).

9. The device (1) according to one or more of the preceding claims, characterized in that said at least one locking head (37) has a respective mating surface (37a) which is configured to engage so that it can slide, during the movement of said elongated latch-like body (36) along the first orientation (302a), with a complementarily-shaped surface (38a) defined on the respective locking seat (38).

10. The device (1) according to one or more of the preceding claims, characterized in that said mating surface (37a) lies on an inclined plane shaped like a wedge with the apex pointed in the same direction as the first orientation (302a) of movement, so that the movement of said elongated latch-like body (36) in the first orientation (301), with the mating edges (11,12) in mutual contact, results in a mutual clamping between said lateral bodies (3a, 3b) that is capable of counteracting their being pulled apart during blow-molding operations.

11. The device (1) according to one or more of the preceding claims, characterized in that said lateral body (3b) that supports said elongated latch-like body (36) is associated with an actuation system (41) for moving a toggle structure (42) which comprises a first lever system (43) and a pusher element (44) for moving said elongated latch-like body (36) on command.

12. The device (1) according to one or more of the preceding claims, characterized in that said lever system (42) is supported so that it can rotate, at a first end, by a supporting footing (46) connected to said lateral body (3b), and is connected at the opposite end to said actuation system (41), said pusher element (44) being hinged, at one end thereof, to an intermediate region of said lever system (43) and, at the opposite end, to said elongated latch-like body (36).

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