Device for blow molding containers

Abstract

A device (1) for blow molding containers (10), comprising a supporting frame for at least one blow molding 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) configured to define, 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 virtue of cyclic opening and closing means (20) about an axis of articulation (101) formed at an interconnection shaft (5), the cyclic opening and closing means (20) being configured to move the blow molding station (3) between an open condition, wherein the lateral bodies (3a, 3b) are mutually angularly spaced around the axis of articulation (101) to define an access opening for loading the preform(s) and for unloading the container(s) from the mold, and a closed condition in which the respective mold parts (4a, 4b) are mutually coupled to define the molding cavity or cavities; the cyclic opening and closing means (20) comprise an electric actuation motor (21) which has an actuation shaft (22) arranged with its axis of rotation (102) parallel to the axis of articulation (101), the actuation shaft (22) being kinematically connected, by virtue of respective kinematic connection means (23), to the lateral movable bodies (3a, 3b) so that the rotation of the actuation shaft (22) about its own axis of rotation (102) results in the rotation of the lateral movable bodies (3a, 3b) about the axis of articulation (101).

Description

[0001] DEVICE FOR BLOW MOLDING CONTAINERS

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

[0003] Systems for blow molding plastic containers are know which comprise an apparatus for blow molding preforms having blow molding stations arranged on rotating feed wheels and with the mold support hinged in a clamshell configuration.

[0004] The opening and closing movements of the blow molding station, as well as the lifting movements of the base portion (or bottom), are normally mechanically controlled.

[0005] In blow molding stations arranged on rotating feed wheels, in particular, curved segments (cams) are used which are arranged so as to be fixed on the frame of the machine and along which cam followers, connected to the elements to be moved, are guided.

[0006] EP 3380300 Bl describes a device for blow molding containers which has a supporting frame for at least one station for blow molding preforms to obtain containers.

[0007] The blow molding station comprises two lateral bodies and a bottom, which are adapted to blow mold at least one container; at least one of the two lateral bodies is movable on command by virtue of means for cyclic opening and closing with respect to the supporting frame around an articulation axis.

[0008] This device is provided with means for kinematic connection between the movable lateral body and the bottom which are adapted to cyclically cause the movement of the bottom along a direction of movement that is substantially parallel to the articulation axis.

[0009] The cyclic opening and closing means comprise an actuation body supported by a connecting linkage, which is movable with respect to the supporting frame about a hinge axis that is substantially parallel to the articulation axis; the connecting linkage is kinematically connected to the movable lateral body and is rotatably associated with a shaped body, which can move along a rectilinear trajectory and forms a cam-like profile which can be engaged by an engagement element supported by the bottom.

[0010] In many applications, where movement of both lateral bodies of the mold is expected, the articulation axis is arranged towards the carousel axis, in a position that is spaced from the pitch circle.

[0011] This constructive solution requires, in order to ensure an opening that is sufficient for feeding of the preform and for unloading the container from inside the mold, a considerable overall dimension of the movable lateral bodies of the mold in the open condition.

[0012] Moreover, known solutions do not allow to optimize the opening and closing movement of the movable lateral bodies.

[0013] Moreover, by spacing the axis of articulation from the lateral bodies, the stresses acting on the parts of the mold are quite high, and this makes it necessary to increase the cross- sections of the various components and, consequently, the overall dimensions.

[0014] The aim of the present invention is to provide a device for blow molding containers that is capable of improving the background art in one or more of the aspects indicated above.

[0015] Within this aim, an object of the invention is to provide a device for blow molding containers that allows to reduce the overall dimensions and to avoid excessive stresses on the moving parts.

[0016] Another object of the invention is to provide a device for blow molding containers that allows high flexibility of operation, being optionally able to adjust the opening and closing movements of the molds.

[0017] Not the least object of the invention is to provide a device for blow molding containers that is highly reliable, relatively easy to provide and has competitive costs.

[0018] This aim, as well as these and other objects that will become more 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, illustrated by way 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 top view of the blow molding station in the open condition;

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

[0024] Figure 5 is a lateral elevation view of the blow molding station with the bolts open;

[0025] Figure 6 is a lateral elevation view of the blow molding station with the bolts closed;

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

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

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

[0029] Figure 10 is a 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 is a view of the actuation shaft of the cyclic opening and closing means;

[0031] Figure 13 is a view similar to the view of Figure 1, of a constructive variation 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, which is generally designated by the reference numeral 1 and has a supporting frame for at least one station 3 for blow molding preforms to obtain containers 10.

[0033] The blow molding station 3 comprises two lateral bodies (3a, 3b), also known as mold holders, and a bottom.

[0034] Each lateral body 3a, 3b is associated with a respective mold part 4a, 4b, which are configured to form, when mutually adjacent, 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 virtue of means 20 for cyclic opening and closing about an articulation axis 101 which is substantially parallel to the axis of at least one container 10 to be provided.

[0036] The articulation axis 101 is defined at an interconnection shaft 5 about which respective coupling elements 5a, 5b rotate which are integral in rotation about the articulation axis 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 consequently the respective mold parts 4a, 4b, are mutually angularly spaced around the articulation axis 101 to form an access opening for loading the preform into the mold and for unloading the container from the mold, and a closed condition in which the respective mold parts 4a, 4b are mutually adjacent and coupled to form the mold cavity or cavities.

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

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

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

[0041] In general, the mutual locking means 30 are arranged adjacent to the external surface of the mold parts 4a and 4b.

[0042] The mutual locking means 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 coupled mating edges 11, 12.

[0043] The term neutral plane 200 refers to the place where the bending tensions due to the action of stress forces, in this case acting during the molding step, are equal to zero.

[0044] In this case, the term neutral plane is intended to mean not a perfectly flat surface, but a curved surface that substantially follows the curvilinear extension of the lateral bodies 3a, 3b.

[0045] According to a further aspect, the locking means 30 are arranged between the neutral plane and the external surface of the mold parts 4a, 4b.

[0046] With the wording "substantially at the neutral plane" it is intended that the locking means 30 are arranged within a distance of 5 mm, and more preferably within a distance of 3 mm, with respect to the position of the neutral plane, for a dimension (diameter) of the external surface of the mold parts 4a, 4b in the closed condition comprised between 100 mm and 300 mm.

[0047] According to the embodiment shown in the figures, one of the lateral bodies, designated in the figures by the numeral 3 a, has a first and a second mating edge I la, 11b which are configured to be mutually coupled with a first and a second mating edge 12a, 12b, respectively, of the other lateral body 3b.

[0048] Conveniently, the 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.

[0049] Advantageously, the means 30 for mutual locking between the mating edges 11, 12 of the lateral bodies 3a, 3b in the mutual coupling condition comprise first mutual locking means 31 acting between the first mating edges I la, 12a and second mutual locking means 32 acting between the second mating edges 1 lb, 12b.

[0050] Both the first mutual locking means 31 and the second mutual locking means 32 are arranged substantially at the neutral plane 200 of the portion of the lateral bodies 3a, 3b located at the respective mutually coupled mating edges 11, 12.

[0051] This constructive solution allows to minimize the stresses on the lateral bodies 3a, 3b due to the blow molding operations.

[0052] With reference to the embodiment shown in the figures, the first mutual locking means 31 are arranged on the side directed outward of the blow molding station 3, while the second mutual locking means 32 are arranged on the side directed inward of the blow molding station 3.

[0053] The side directed outward is understood to mean the region of the molding station 3 at which the preforms are fed and the containers 10 are unloaded, while the side directed inward is the one arranged proximate to or at the articulation axis 101.

[0054] If, as is common, the blow molding stations 3 are mounted at the peripheral region of a carousel structure, the side directed outward corresponds to the external side, while the side directed inward relates to the side directed toward the axis of rotation of the carousel.

[0055] In the embodiment shown, the articulation axis 101 is arranged externally to the lateral bodies 3 a, 3b proximate to the second mutual locking means 32. As an alternative, it is possible to provide that the blow molding station 3 only has the first mutual locking means 31 at the side directed outward of the blow molding station 3, while the interconnection shaft 5 that defines the articulation axis 101 is positioned in a diametrically opposite position, between the second mating edges 11b, 12b.

[0056] In this case, the interconnection shaft 5 between the lateral bodies 3a and 3b is arranged at the neutral plane 200.

[0057] According to a preferred practical embodiment, the mutual locking means 30 comprise at least one bolt, and in particular at least one elongated bolt-like body 36, which is supported by one of the lateral bodies (the lateral body 3b in the figures), is arranged with its main axis of extension 301 substantially parallel to the axis of articulation 101 and can move on command along a direction of movement, indicated by the arrows 302, which is parallel to its main direction of extension 301.

[0058] The elongated bolt-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 bolt-like body 36 along a first direction 302a of the movement path 302, in a respective locking seat 38 formed at the other lateral body 3 a.

[0059] Preferably, the elongated bolt-like body 36 has a plurality of locking heads 37 which are mutually spaced along the main direction of extension 301; similarly, multiple locking seats 38 are formed at the other lateral body 3a and are also mutually spaced so as to correspond to the distance between the locking heads 37, along a direction of extension.

[0060] Each locking seat 38 is designed to be engaged by a respective locking head 37 following the movement of the elongated bolt-like body 36.

[0061] The locking head or heads 37 have a respective coupling surface 37a configured to engage slidingly, during the movement of the elongated boltlike body 36 along a first movement direction 302a, a complementarily shaped surface 38a which is formed at the respective locking seat 38 and faces the respective coupling surface 37a.

[0062] The coupling surface 37a lies on a wedge-shaped inclined plane with the tip directed in the same direction as the first direction of movement 302a so that the movement of the elongated bolt-like body 36 in the first direction of movement 302a, with the mating edges 11 and 12 close together, can cause a mutual tightening between the lateral bodies capable of counteracting their separation during blow molding operations.

[0063] Preferably, the lateral body 3b that supports the elongated bolt-like body 36 is associated with an actuator 41, typically a pneumatic cylinder 41a, for the movement of a toggle structure 42 comprising a first lever system 43 and a pusher element 44.

[0064] The lever system 43 is rotatably supported, at a first end, by a supporting footing 46 connected to the lateral body 3b, and is connected at the opposite end to the actuator 41, while the pusher element 44 is hinged, at one end, to an intermediate region of the lever system 43 and at the opposite end to the elongated bolt-like body 36 so that the actuator 41 can actuate the movement of the elongated bolt-like body 36 in a first direction 302a of the movement path, in order to provide mutual locking between the respective mating edges 11 and 12, and in the opposite direction of movement 302b to allow the mutual spacing of the respective mating edges 11 and 12 and consequently the transition of the blow molding station 3 to the open condition.

[0065] According to a further aspect of the present invention, the movable lateral bodies 3 a and 3b are actuated, in their rotation about the articulation axis 101, by the cyclic opening and closing means 20.

[0066] With reference to the embodiment shown in the figures, the cyclic opening and closing means 20 comprise an electric actuation motor 21 having an actuation shaft 22 arranged with its axis of rotation 102 parallel to the axis of articulation 101.

[0067] The actuation shaft 22 is kinematically connected, by virtue 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 axis of rotation 102 causes the rotation of the movable lateral bodies 3a and 3b about the articulation axis 101.

[0068] In particular, the actuation shaft 22 comprises a crankshaft 22a, which is associated with a first and a second actuation linkage 23a and 23b for kinematic connection to a respective movable lateral body 3a and 3b.

[0069] In particular, each actuation linkage 23 a, 23b is connected to a respective interconnection body 24a, 24b which connects the interconnection shaft 5 to the movable lateral bodies 3a and 3b.

[0070] The actuation linkages are hinged, and therefore rotatable, at their longitudinal ends, to the crankshaft 22a and to the respective connection bodies 24a and 24b.

[0071] This constructive choice allows to convert the rotary motion of the crankshaft 22a about its axis of rotation 102 into an oscillating movement of the interconnection bodies 24a and 24b about the articulation axis 101.

[0072] The solution adopted allows to open cyclically the mold parts 4a and 4b by rotation of the actuation shaft 22.

[0073] Moreover, by acting on the rotation of shaft 22 it is possible to act on the breadth of the opening of the bodies 3 a and 3b.

[0074] With reference to what is shown in Figure 13, the supporting footing 46, at least in one part thereof, can be connected to the respective movable lateral body, in this case the lateral body 3b, by virtue of elastic compensation means 45 which make the kinematic assembly less rigid, so as to compensate for any tolerances.

[0075] The operation of the device 1, according to the invention, is as follows.

[0076] The preforms to be blow molded are fed to the blow molding station 3, when it is in the open condition, by feeding devices of a known type.

[0077] At this point, once the preform(s) is / are accommodated inside the mold parts 4a and 4b, the cyclic opening and closing means 20, constituted for example by the crankshaft 22a, actuate the rotation of the movable lateral bodies 3a and 3b to turn them about the articulation axis 101 so as to bring the respective ones mutually closer and bring the blow molding station 3 into a closed condition.

[0078] Once the respective mating edges 11 and 12 of the lateral bodies 3 a and 3b are mutually adjacent, the mutual locking means 30 are activated by means of the movement, by the toggle structure 42, of the elongated boltlike body 36 which is moved along the first direction of movement 302a so as to engage the locking heads 37 in the respective locking seats 38.

[0079] The mutual locking means 30, arranged at the neutral planes 200, allow to minimize stress, thus reducing the overall dimensions and crosssections of said mutual locking means 30 and of the lateral bodies 3a and 3b.

[0080] In the closed condition, and with the mutual locking means 30 activated, the preform is blow molded to obtain the container 10.

[0081] Once the blow molding operations are finished, the mutual locking means 30 are deactivated, moving the elongated bolt-like body 36 along the movement direction 302b of the movement path 302, so as to allow the lateral bodies 3a and 3b to open to allow the unloading of the blow molded container 10.

[0082] In practice it has been found that the invention achieves the intended aim and objects, providing a device that has limited overall dimensions since the moving parts are subject to extremely low stresses.

[0083] Moreover, by virtue of the particular structure of the mutual locking means 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, above all, energy during operation.

[0084] The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the accompanying claims; moreover, all details may be replaced with other technically equivalent elements.

[0085] In practice, the materials used, as long as they are compatible with the specific use, as well as the contingent shapes and dimensions, may be any according to the requirements and the state of the art.

[0086] The disclosures in Italian Patent Application No. 102024000003493, from which this application claims priority, are incorporated herein by reference. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included 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), comprising a supporting frame for at least one blow molding station (3), said blow molding 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) configured to define, 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 virtue of cyclic opening and closing means (20) about an axis of articulation (101) formed 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, wherein said lateral bodies (3a, 3b) are mutually angularly spaced around said axis of articulation (101) to define an access opening for loading the preform(s) and for unloading the container(s) from the mold, and a closed condition in which the respective mold parts (4a, 4b) are mutually coupled to define the molding cavity or cavities, characterized in that said cyclic opening and closing means (20) comprise an electric actuation motor (21) which has an actuation shaft (22) arranged with its axis of rotation (102) parallel to the axis of articulation (101), said actuation shaft (22) being kinematically connected, by virtue of respective kinematic connection means (23), to said lateral movable bodies (3 a, 3b) so that the rotation of said actuation shaft (22) about its own axis of rotation (102) results in the rotation of said lateral movable bodies (3a, 3b) about said axis of articulation (101).

2. The device (1) according to claim 1, characterized in that said actuation shaft (22) comprises a crankshaft (22a) associated with first and second actuation linkages (23a, 23b) for kinematic connection to a respective movable lateral body (3a, 3b), each lateral body (3 a, 3b) having at least one respective mating edge (11, 12), the mating edges (11, 12) of each lateral body (3a, 3b) being intended, in the closed condition of the blow molding station (3), to mutually couple in order to enable, during blowmolding operations, the locking of the mold parts (4a, 4b).

3. The device (1) according to claim 2, characterized in that each one of said actuation linkages (23a, 23b) is connected to a respective interconnection body (24a, 24b) which connects said interconnection shaft (5) to said movable lateral bodies (3a, 3b).

4. The device (1) according to claim 2, characterized in that said blow molding station (3) comprises means (30) for mutual locking between the mating edges (11, 12) of the lateral bodies (3a, 3b) in a condition of mutual coupling.

5. The device (1) according to one or more of the preceding claims, characterized in that said blow molding station (3) comprises means (30) for mutual locking between the mating edges (11, 12) of the lateral bodies (3a, 3b) in a mutually coupled condition, said mutual locking means (30) being arranged substantially at a neutral plane (200) of the portion of the lateral bodies (3a, 3b) located at the respective mutually coupled mating edges (11, 12).

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

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