Patent Application
20230083869
The present disclosure relates to a device for the cooling and extraction of preforms for the manufacture of plastic containers.
Devices are known for unloading and storing preforms for the manufacture of plastic containers, which are normally constituted by a cooling plate which forms a plurality of receptacles arranged like a matrix and designed to accommodate respective preforms that are still warm for the time necessary to cool them at least partially.
Typically, such preforms are fed directly from the injection molding press to the cooling plate and remain in the respective receptacle for a preset time.
Specifically, once the injection process, i.e. the step in which the male and female mold parts remain in a closed position, has ended, the mold opens and the cooling plate is moved towards the preforms partially accommodated in one of the two mold parts so that the receptacles of the cooling plate can engage with respective portions of preforms emerging from the mold part and extracted therefrom so as to allow the closure of the mold and a new molding cycle.
The unloading of the preforms from the cooling plate occurs as a consequence of an expulsion action that can be obtained with pneumatic means, mechanical means, or a combination thereof.
After the expulsion from the cooling plate by the pusher elements, the preforms, by now at least partially cooled, fall by gravity onto a conveyor belt, which then makes them fall, again by gravity, into a container.
The solution described above, while being widely used, is not however free from drawbacks.
First of all, the preforms, although they have undergone a certain cooling, still have some of their portions, typically the bottom one, that are not perfectly rigid and therefore falls can cause localized deformations.
Furthermore, the cooling times are in many cases quite long and this does not allow to optimize the productivity of the apparatus as a whole.
A solution is known from EP0947304 in the name of Husky which allows to speed up the cooling process by using a jet of air to lower the temperature of the internal surface of the preforms.
In particular, said patent document describes a preform molding and cooling apparatus that provides for the removal of the preforms from the preform mold when they are not completely cooled and the subsequent cooling of the preforms outside the molding area; the described solution teaches to perform the cooling of the preforms by injecting a jet of air inside the preforms, cooling the outside of the preform in a classical way, i.e., by cooling the receptacle by means of a coolant fluid, or by convection.
Other similar solutions provide for cooling the inside of the preforms by using jets of air.
However, known solutions have a certain complexity from a constructive standpoint, since they have to manage on the same cooling plate both the operations for introducing air to be directed inside the preforms and the removal of the preforms from the grip hand in order to subsequently unload them.
In some cases, plates have been proposed in which the same elements might selectively provide the jet of air, in order to cool the preforms, or the vacuum to extract them from the grip hand.
As an alternative, solutions have been devised in which the cooling plate supports a plurality of blow molding elements and a plurality of grip elements.
The aim of the present disclosure is to eliminate, or at least reduce drastically, the drawbacks mentioned above.
Within this aim, the disclosure provides a device for the cooling and extraction of preforms for the manufacture of plastic containers that allows to cool and extract, in an extremely practical and effective manner, the preforms from the grip assembly.
the disclosure also provides a device for the cooling and extraction of preforms for the manufacture of plastic containers that allows to manage in an optimum manner both the cooling operations and the unloading operations, simplifying the movements of the various components so as to optimize both operations.
This aim and these and other advantages which will become better apparent hereinafter are achieved by providing a device for the cooling and extraction of preforms for the manufacture of plastic containers according to the provisions of claim 1.
Further characteristics and advantages of the disclosure will become better apparent from the description of some preferred but not exclusive embodiments of a device for the cooling and extraction of preforms for the manufacture of plastic containers according to the disclosure, illustrated by way of non-limiting example in the accompanying drawings, wherein:
With reference to the figures, the present disclosure relates to a device, generally designated by the reference numeral 1, for the cooling and extraction of preforms 10 for the manufacture of plastic containers.
The device 1 comprises at least one grip assembly 2 which forms a plurality of receptacles for respective preforms 10 and means for transferring the still warm preforms from a molding device, for example an injection molding device, to the grip assembly 2.
The device 1 has a cooling and extraction assembly 20.
The cooling and extraction assembly 20 is designed to cool the preforms 10 arranged at the grip assembly 2 and to extract the cooled preforms 10 from the grip assembly 2.
The cooling and extraction assembly 20 comprises a cooling plate 21 which is arranged, at least in one operating condition thereof, so as to face the grip assembly 2.
The cooling plate 21 can, in particular, move on command with respect to the grip assembly 2 between a position that is closer to the grip assembly 2 and a position that is spaced from the grip assembly 2.
In this regard, the cooling plate 21 can be movable, by virtue of motor means, with respect to a supporting structure that is fixed or connected kinematically to a movable element in order to move into the operating condition in which it is closer to the grip assembly 2.
With reference to
In this manner, the approach/spacing movement of the cooling plate 21 does not require dedicated motor means but is determined by the opening and closing movement of the press itself.
The cooling plate 21 supports a plurality of cooling channels 22.
The cooling channels 22 are functionally connected to a device for the production of an air flow, constituted for example by a blower 22a or by a compressor.
In one embodiment, the device for producing an air flow can be integral with the cooling plate 21.
In another embodiment, shown in
The device for producing an air flow may also be associated with cooling means which comprise, for example, a heat exchanger and are adapted to thermally condition the air flow.
In this configuration, the device for producing the flow and the cooling means are preferably connected to fixed elements of the line.
The cooling channels 22 are designed, with the cooling plate 21 in the closer position, to lead into a respective preform 10 accommodated in a respective receptacle 3 in order to convey a jet of air inside the preform 10, so as to increase its cooling rate.
Furthermore, the cooling and extraction assembly 20 comprises an unloading plate 23, which is arranged on the opposite side of the grip assembly 2 with respect to the cooling plate 21.
The unloading plate 23 supports a plurality of grip bodies 24, which can be moved on command in order to pass through the cooling plate so as to engage selectively, when the cooling plate 21 is in the closer position, with a respective preform 10 in order to allow its extraction from the respective receptacle 3.
Advantageously, the grip assembly 2 comprises a grip plate 4 which supports a plurality of receptacles 3 for a respective preform 10.
The grip plate 4 is movable with respect to the molding device in order to pick up the preforms.
The grip plate 4 can furthermore move on command along at least one positioning direction that is substantially perpendicular to the axis of the preforms 10 so as to arrange the preforms 10 extracted in each instance at the cooling channels 22 or at the grip bodies 24.
The receptacles 3 are arranged like a matrix on a plane of arrangement.
Conveniently, the cooling plate 21 is provided with crossing openings 26 for the grip bodies 24 during the step of engagement with the respective preforms 10 and in the step of extraction of the preforms 10.
With reference to the embodiment shown in
However, it has been found that it is particularly advantageous that the crossing openings are formed by a plurality of slits 26a with a substantially vertical extension.
Conveniently, the slits 26a are open downward.
In practice, in this constructive variation, if a preform 10, for any reason, is not picked up in an optimum manner by the grip bodies 24, it can fall freely without risking getting stuck in the crossing opening 26.
With reference to the constructive variation shown in
In fact, this embodiment allows, with the help of deflectors and/or of particular geometries of the channels, to ensure a substantially even flow on all the cooling channels 22.
The evident advantage is that it is possible to use a single blower, if provided, and a single tubular element, thus providing space in the lower part of the grip assembly 2 with consequent facilitation in the access and management of the rotation of the unloading plate 23, and allowing to have regions in which the preforms that are not gripped correctly can stop.
Conveniently, the cooling plate 21 is arranged substantially parallel to the plane of arrangement of the receptacles 3.
In particular, the cooling plate 21 can move between the spaced position and the closer position along a movement direction 100 that is substantially perpendicular to its plane of arrangement.
Advantageously, the unloading plate 23 can move between a disengagement position, in which the grip bodies 24 are arranged on the opposite side of the grip assembly 2 with respect to the cooling plate 21, and an engagement position, in which the grip bodies 21 are at least partially arranged on the same side of the grip assembly 2 with respect to the cooling plate 21 in order to allow its engagement with a respective preform 10.
Conveniently, the unloading plate 23 can move, in its disengagement position, between a condition for retaining the respective preforms 10 and a position for unloading the respective preforms 10.
Advantageously, the unloading plate 23 in the engagement position is arranged so that its plane of arrangement is arranged substantially vertically, while it is convenient to provide that the plane of arrangement, in the unloading position, is arranged substantially horizontally so that the preforms 10 are directed downward.
Preferably, the grip bodies 24 comprise a retention device for a respective preform 10.
The retention device can be actuated on command in order to pass between an active condition, in which it allows the locking of the respective preform 10, and an inactive condition, in which it allows coupling and uncoupling with the respective preform 10.
The retention device comprises an engagement head which is associated with actuation means of the mechanical type or pneumatic type.
The operation of the device 1 is as follows.
At each molding cycle, the grip assembly 2 is moved in order to allow the transfer of the preforms 10 that have just been molded in respective receptacles formed at the grip assembly 2 and to arrange it facing the cooling and extraction assembly 20.
At this point, the cooling plate 21 is moved on command from the position that is spaced from the grip assembly 2 toward the position that is closer to the grip assembly 2.
In the closer position, the cooling channels 22 are arranged at the cavities of the respective preforms 10 to be cooled and the air sent toward the cooling channels is then directed inside said preforms 10 in order to determine their cooling by convection of the injected air.
While the cooling plate 21 is moved to the closer position, the grip bodies 24 supported by the unloading plate 23 are moved to cross the cooling plate 21 in order to engage respective preforms 10 (not engaged by the cooling channels 22) which are to be extracted from their respective receptacles, having already previously performed one or more cycles for injecting air by means of the cooling channels 22.
In the meantime, the cooling channels 22 continue to inject air into the respective preforms 10 while the grip bodies 24 are moved to the retention condition so as to lock thereon the respective preform 10.
At this point, the unloading plate 23 and, with a conveniently synchronized movement, the cooling plate 21 are moved away from the grip assembly 2 so as to disengage the cooling channels 22 from the respective preform 10, and to move the preforms 10 retained by the grip bodies 24 so that they cross the cooling plate 21 in order to reach its disengagement position, and therefore, from the condition for retention of the respective preforms 10, to the position for unloading the respective preforms 10, by means of a downward rotation about a substantially horizontal pivoting axis.
In the meantime, the preform molding device has completed a new molding cycle and the still-warm preforms are transferred at the receptacles of the grip assembly 2 that have just been freed.
The grip assembly 2 then moves to a position in which the receptacles are offset with respect to the previous position, so that the grip bodies 24 can engage the preforms 10 that have already finished the cooling cycles.
The proposed solution, by making the cooling step substantially independent of the unloading step, allows to optimize the operations for cooling (making them dependent only on the molding steps) and unloading (with movement dynamics that can be slower indeed because of the longer time made available by the separation of the cycles).
Furthermore, the device according to the disclosure allows to adjust the position of the cooling channels 22 without worrying about the movement of the grip bodies.
The disclosure thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.
In practice, the materials used, so long as they are compatible with the specific use, as well as the shapes and dimensions, may be any according to the requirements.
All the details may furthermore be replaced with other technically equivalent elements.
The disclosures in Italian Patent Application No. 102020000002722 from which this application claims priority are incorporated herein by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102020000002722 | Feb 2020 | IT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/052440 | 2/2/2021 | WO |
