EP4180344A1

EP4180344A1 - Wrapping assembly with horizontal axis winding and relative reel change unit

Info

Publication number: EP4180344A1
Application number: EP22201523.2A
Authority: EP
Inventors: Davide Angelo CORBERI
Original assignee: Area Srl
Current assignee: Area Srl
Priority date: 2021-10-14
Filing date: 2022-10-14
Publication date: 2023-05-17
Also published as: IT202100026303A1

Abstract

It is disclosed a wrapping system with horizontal-axis wrapping employing a plastic film, comprising a winding machine (A) provided with a reel-carrying unit (P) rotatably mounted on a circular path on a substantially vertical plane, the reel-carrying unit (P) comprising at least a support shaft (4) and a tensioning roller (5) arranged parallel at a distance from one another, wherein said system furthermore comprisesa reel storage (M), anda replacement carriage (C),the replacement carriage (C) comprising at least a cradle (22), slidable between said storage (M) and said winding machine (A), whereon there are mounteda first drawing carriage (20) for a reel (B1) anda second drawing carriage (21) for a flap of film (F1) of the reel (B1),said first (20) and second (21) carriage being mounted translatable crosswise to said slidable cradle (22) andsaid second carriage (21) being equipped with gripping means (27) mounted translatable according to an axis having at least a major component in a vertical direction (Z).

Description

Field of the invention

The present invention relates to a wrapping system with horizontal-axis wrapping, in particular a wrapping system equipped with automatic reel change unit.

Background art

The practice of wrapping packages with a wrapping of thin film made of a plastic material is known.
In particular, the application of an stretchable plastic film is achieved with machines which wrap the packages to be packaged with one or more loops of film, preferably stretchable film. Wrapping takes place by defining a relative rotation between a reel of plastic film and a package to be packaged, also establishing a relative movement between the reel and the package to be packaged along an axis of movement to determine winding loops spread over a certain length.
A first major distinction in this technological field relates to the direction of movement used to create the winding, which can take place according to a vertical axis (for example in the traditional pallet wrapping machines), along which the goods to be packaged are stacked upright, or according to a horizontal axis, along which the goods to be packaged are fed. In the latter case, each of the goods is fed to the packing station along a conveyor belt or roller conveyor, then wrapped in film and then further fed along the packing line's conveyor belt.
According to the prior art, for winding the film around a horizontal axis, a winding machine equipped with a reel-holder carriage is provided, which is moved along a circular guide arranged in the packaging station in a vertical plane oriented perpendicularly to the goods conveyor line and encircling said horizontal conveyor line. In the packaging station, the package is supported with appropriate guide means so that, upon rotation of the reel holder carriage, the film can unwind from the relative reel and freely perform a wrapping which encircles the package to be packaged. The spiral pattern of the film is obtained by combining the circular rotation of the reel on the vertical plane with a relative movement of the package to be packaged. Exemplary winding machines are disclosed in Italian Patent Application Nos. MI2011A01543 and US4050220 , while another type for steel coils (where the plastic film spiral enters the central core of the steel coil), is illustrated in the context of the accompanying Figures.
In this type of machine, the film reel is mounted on a support shaft with horizontal attitude, which is mounted on the mobile carriage on a circumferential path that lies on a vertical plane. The relative movement of the goods consists of a rotation of the steel coil about a vertical axis, so as to distribute the winding loops over the entire coil. When the film reel is substantially used up, it is manually removed from its support shaft and replaced with a new one. Obviously, this phase leads to a waste of time and the use of skilled labour, which have an impact on packaging costs. This problem is particularly noticeable in machines where the film reels are necessarily of small diameter, for example in the packaging of toroidal products (such as metal coils) where the reel must pass inside the central hole: the smaller the reel, the more frequently it runs out and must be replaced.
Instead, it would be desirable to have an automatic system to replace the reels when they run out and avoid a prolonged stoppage of the machine during the replacement.
IT2007901486029 relates to a reel change unit, which provides for the automatic replacement of film reels alternately between two opposite units. This solution avoids a prolonged machine downtime, but forces the operator to intervene manually at each reel change to replace the used-up reel. A similar solution is disclosed in WO2016/193875 .
Another solution is disclosed in US2005/193687A1 . In this case, an embodiment is provided with a plurality of reels mounted on a revolver carrier, but the entire carrier is moved in close proximity to the reel change zone, with a significant bulk and considerable construction complexity.
US2015/90831A1 discloses a reel change unit with a storage that houses a plurality of reels. The transfer of the reels to the replacement area is achieved with an anthropomorphic arm, notably flexible but very expensive.
To date, the market for these machines has not offered any convincing solution to make the process of replacing the plastic film reels automatic, without involving frequent intervention by the operator and at reduced costs.
Consequently, there is a need to provide a packaging system and associated reel change unit that overcomes the drawbacks of the prior art.

SUMMARY OF THE INVENTION

This object is achieved by a system and a unit with the essential characteristics described in the attached independent claims.
Specific and advantageous features are disclosed in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the system according to the present invention will in any case become more evident from the following detailed description of a preferred embodiment of the same, provided purely by way of a non-limiting example and illustrated in the accompanying drawings, wherein:

Fig. 1 is a schematic frontal elevation view of the system according to the present invention;
Fig. 2 is a perspective view of the system in Fig. 1;
Fig. 3 is a partial enlarged view from a different perspective of the system in Fig. 1;
Fig. 4 is an enlarged perspective view of the storage component and the replacement carriage;
Fig. 4A is a detailed perspective view of a portion of the storage;
Fig. 5 is a partial perspective view of detail of the replacement carriage in a drawing phase;
Fig. 6A and 6B are views from two different perspectives of the parking area where an ejection fork is installed;
Fig. 7 is a partial front elevation view of a detail of the area illustrated in Fig. 6A;
Fig. 8A is a similar view to Fig. 5 at a higher magnification;
Figs. 8B and 8C are views similar to that of Fig. 8A from a different perspective;
Figs. 9A and 9B are partial perspective views of a gripper in two different states;
Figs. 10A and 10B are partial perspective views of an expandable shaft in two different conditions; and
Figs. 11A-18 are partial views according to different perspectives of various operating phases of the system according to the invention, in a mirror variant (righthand instead of lefthand) compared to that shown in Figs. 1-10B.

DESCRIPTION OF PREFERRED EMBODIMENTS

While the present system and units are subject to different embodiments, they are shown in the figures and will be described below as a preferred embodiment. It is to be understood that the present disclosure is to be considered as an exemplification of the whole and is not to be understood as limited to the specific embodiments set forth.
Fig. 1 shows a wrapping system with winding along a horizontal axis, equipped with an automatic reel change unit. The system is composed of three main, mutually cooperating parts: a winding machine (A), a reel housing or storage (M) and a replacement carriage (C).
The aforementioned main parts and their structures are supported on the ground and connected to each other by means of support and traditional connections, which are not part of what taught is specifically shown here.
The winding machine A is designed according to a diagram known per se and therefore will not be described in detail. In schematic terms, the machine A is composed of a main frame 1 that extends in an arc on a vertical plane (closed at O or open at C as in the figures) embracing a horizontal transport plane (not identified in the figures), on which a plurality of rollers 2 with a substantially horizontal axis are mounted, suitable for guiding a transfer ring 3 that lies on a substantially vertical plane.
The transfer ring 3 is closed or open (as shown in the figures) and is arranged between the rollers 2 so that it can rotate on the vertical plane of the frame 1 around a fixed horizontal rotation axis. The rotational movement of the transfer ring 3 is determined by an appropriate drive, for example acting on some of the rollers 2.
On the horizontal transport plane (not shown) the packages to be packaged arrive (for example, a toroidal package L is shown in the figures, for example a metallic coil) until they stop at the transfer ring 3. To this end, the support frame 1 has a large open portion around the axis of rotation of the ring 3, so as to leave space for the passage of the package to be packaged L.
A reel-carrying unit P (see Fig. 3) of traditional configuration is mounted on the transfer ring 3, integral in rotation. The unit P consists of a transfer carriage 3a on which a support shaft 4 is mounted, adapted to support a reel of plastic film B, a tensioning roller 5 and a return roller 6, all with respective longitudinal axes parallel to the rotation axis of the ring 3.
The film reel B is supported on the shaft 4 free to rotate but suitably braked. The tensioning roller 5 is arranged at a certain distance from the axis of the reel B and is mobile on the transfer carriage 3a, so as to be able to adjust the relative distance from the reel B and keep the film stretching between the reel B and the package to be packaged L under tension, via the return roller 6.
In a reel changing position, the transfer ring 3 is preferably arranged to stay in the position indicated in Fig. 3, i.e. with the tensioning roller 5 arranged vertically above the reel B, for the function that will be illustrated below.
According to the invention, the reel storage M and the replacement carriage C are arranged on one side of the winding machine A.
The storage M is arranged to support a plurality of plastic film reels B1, all arranged in an orderly manner with the respective parallel winding axes. To this end, a support panel 9 of the storage M is provided with a plurality of support shafts 10 - intended to couple with the cores of the film reels B1 - and corresponding retaining assemblies 11 arranged to retain a free flap of the film. The reels B1 can be loaded by hand into the storage M - by inserting the core on the shafts 10 and engaging the free flap of the film on the retaining assembly 11.
In the illustrated embodiment, an array of eight reels B1 is arranged in two rows: to manage more than one row of reels at different heights it is preferably provided that the support panel 9 is adjustable in height by means of a respective lifting actuator 12.
Proximity sensors 13 are also provided, at each shaft 10, to detect the presence of the reels B1 and to determine whether the respective seat is empty or full.
The retaining assemblies 11 are comprised of a return roller 11a and a retaining tweezers 11b arranged one below the other, to retain in a stretched state a section F1 of the initial flap of the film, as clearly shown in Fig. 4A.
The replacement carriage C is comprised of a pair of movable carriages 20 and 21, mounted on a cradle 22 slidable along a pair of transfer rails 23 arranged between the storage M and the parking area of the reel-carrying unit P.
The cradle 22 is moved along the tracks 23 by any known type of drive system, for example a ring drive belt N controlled by a relative sliding motor.
The two movable carriages 20 and 21 are mounted on the cradle 22 movable transversely to the longitudinal movement of the cradle 22, by means of respective actuators 20a and 21a.
On a first carriage 20 there is provided a bracket 24 which carries the expandable shaft 25 designed to be inserted into the core of a film reel B, B1 and hold it in a controlled manner. According to one embodiment, the expandable shaft 25 is composed of four articulated pieces, separable from one another in pairs - for example by means of a pneumatic actuator - to define a kind of reverse gripper, as illustrated in Figs. 10A and 10B. In the collapsed condition (Fig. 10a) the shaft 25 has a diameter slightly smaller than the diameter of the core of the reels B, B1 and can be inserted into the core with play; in a expanded condition (Fig. 10B), the retractable components of the shaft 25 expand and grip the inner surface of the core, holding the reel B, B1. The expandable shaft 25 is controlled, for example by means of a respective pneumatic actuator 25a (possibly in contrast with elastic means).
On a second carriage 21 there is arranged a lifting means 26 provided with a transfer gripper 27. In particular, according to the embodiment shown in the figures (see in particular Figures 8A and 8B), the lifting means 26 is in the form of a pedestal 26a which supports a first actuator 26b provided with a moving slider 26c. On the moving slider 26c a drawing gripper 27 is mounted integrally, equipped with two flat jaws suitable for firmly tightening a flap of film, in particular the end flap F1 of one of the reels B, B1. The transfer gripper 27 is controlled in opening (Fig. 9A) or closing (Fig. 9B), for example by means of a second pneumatic actuator 27a (possibly in contrast with elastic means).
According to a peculiar feature of this preferred embodiment, it should be noted that the first actuator 26b is arranged to translate the movable slider 26c according to a straight path slightly tilted with respect to a vertical axis, for example of 15° forward (i.e. with the upper end advanced, in the direction of travel D, with respect to the lower end). Substantially, according to the teaching provided herein, it is important that the movable slider 26c has a movement at least according to a main component in the direction of the vertical axis Z.
According to a preferred embodiment, on the frame 1, in a region corresponding to a rest position of the reel-carrying unit P, there is provided a first station actuator 7 having a movement according to a horizontal axis X and a second station actuator 8 having a movement according to a horizontal direction Y, perpendicular to X, which cooperate with each other in the manner which will be illustrated below (Fig. 6A and 6B). The second station actuator 8 according to the horizontal direction Y is mounted at the end of the first station actuator 7 according to the horizontal axis X. For reasons of overall dimensions, in the illustrated embodiment, the first station actuator crosses the frame 1 from one side to the other, but this mounting mode is not considered to be limiting.
A fork 8a is mounted at the operating end of the second station actuator 8. As can be understood more clearly from Fig. 7, the fork 8a has a shape suitable for engaging and fitting the outer surface of the support shaft 4. In this way, by means of the station actuators 7 and 8, it is possible to bring the fork 8a to couple with the support shaft 4 - when the latter is in the rest position of the ring 3, that is in the reel replacement position illustrated in Fig. 7 - with a transverse movement according to the axis Y and then, with a longitudinal movement according to the axis X, so as to extract the reel B from the support shaft 4.
At this time, once all the component elements of the system according to the invention have been described, it is possible to understand its operation.
The package to be packaged L is brought close to the winding machine A and wrapped with the plastic film F, which unwinds from the reel B during the circular movement of the unit P, in a manner known per se.
When the reel B is substantially used-up - a condition that can be determined by means of appropriate sensors - the rotation of the transfer ring 3 is stopped in the rest position, i.e. with the unit P in the position shown in Fig. 7, with the tensioning roller 5 substantially above the support shaft 4. In this condition, the second station actuator 8 is advanced in the X direction (Fig. 11A) until the fork 8a is carried to couple with the support shaft 4, behind the core of the used-up reel B. Then the first station actuator 7 is also actuated along the horizontal axis X (Fig. 11B), which expels the core of the reel B from the support shaft 4. The core falls to the ground, where it meets a chute (not shown) that conveys it to the outside of the machine.
Meanwhile, the carriage C has been brought into a drawing position, in front of a preselected reel B1 of the storage M. In this phase, the slider 26c is in a lower position, the gripper 27 is in the open position, while the expandable shaft 25 is in a collapsed condition (smaller diameter).
The two carriages 20 and 21 are pushed towards the storage M, so as to engage the expandable shaft 25 in the core of a chosen reel B1 and bring the gripper 27 to couple with an initial flap of film F1. By means of the actuators 25a and 27a the expandable shaft 25 is expanded, so as to firmly engage the core of the reel B1, while the gripper 27 is tightened on the flap F1 (Fig. 12). At this point, the carriages 20 and 21 can be pushed back again, disengaging the reel B1 and the flap F1 from the storage M (Figs. 13A and 13B).
Once the desired reel has been drawn, the cradle 22 can be transferred, along the rails 23, towards the delivery position. In this transfer step, the slider 26c of the actuator 26b is progressively brought to a higher position, i.e. to a higher height than that in which the tensioning roller 5 is located. At the same time, the carriage 21 is pushed into a forward position by the actuator 21a, so as to bring the film flap F1 closer to the unit P (Figs. 14A and 14B).
During the movement of the reel B caused by the slider 26c, the film tape shall be partially let to unwind. Therefore, the reel fitted on the expandable shaft 25 must be allowed to rotate. To this end, the pneumatic pressure input to the expandable shaft 25 can be reduced, to allow a partial collapse and release of the core of the reel, or the expandable shaft 25 can be mounted freely rotatable, possibly clutched, on the carriage 20.
The cradle 22 is pushed to a position where the gripper 27 is located just downstream of the tensioning roller 5. Then, the slider 26c is lowered back to the lower position, following the inclination of the actuator 26b: in this way, the film end flap F1 is brought beneath but upstream of the return roller 6 (Fig. 15). The cradle 22 can be further advanced, transferring the film flap F1 downstream also of the return roller 6 (Fig. 16) and bringing the reel B1 into alignment with the support shaft 4: at this point, the carriage 20 can also be advanced (perpendicular to the movement of the cradle 22), until the core of the reel is inserted on the support shaft 4 (Fig. 17).
In a final phase, the carriage 20 can be moved back again, after collapsing the expandable shaft 25, and the unit P is moved by a stroke sufficient to bring the film flap in front of an auxiliary gripper A1 on board the winding machine A (Fig. 18), where the film is taken over to start a traditional winding cycle.
As it is clear from the above description, the system and the reel change unit of the invention perfectly fulfil the purpose set out in the introduction.
In fact, through a relatively simple structure and a carriage with linear actuators, it is possible to obtain an automatic replacement of the reels, which takes place quickly and reliably.
Thanks to the structure of the carriage component, the storage M can store a significant number of reels, even of different types, which can be chosen as desired, based on a system control logic, defining the absolute position of the cradle 22 on the rails 23 with respect to the height position of the storage M.
It is understood that the invention is not to be considered as limited by the particular embodiments described and illustrated, but that different variants are possible, all within the reach of a person skilled in the art, without departing from the scope of protection of the invention itself, which is exclusively defined by the following claims.
For example, although the selection of the drawing position of a reel has been described as obtainable from the combination of the horizontal movement of the cradle 22 with the vertical movement of the storage M, it is not excluded that it can also take place in another way.
Likewise, the specific embodiment of the gripping elements and of the drawing shaft 25 of the reel are to be understood as preferred, but they could take different forms.
Furthermore, the system does not need to provide a tensioning roller 5 arranged above the support shaft 4, because their positions could also be reversed: in this case, the configuration of the transfer carriage component C would also be reversed.
Finally, the gripper 27 could be controlled along the vertical movement component by a perfectly vertical actuator, then being driven according to the desired mixed path (horizontal and vertical) by a coordinated combination of the movements of the slider 26c and the cradle 22.

Claims

Wrapping system with horizontal-axis wrapping employing a plastic film, comprising a winding machine (A) provided with a reel-carrying unit (P) rotatably mounted on a circular path on a substantially vertical plane, the reel-carrying unit (P) comprising at least a support shaft (4) and a tensioning roller (5) arranged parallel at a distance from one another, characterised in that it furthermore comprises
a reel storage (M), and

a replacement carriage (C),

the replacement carriage (C) comprising at least a cradle (22), slidable between said storage (M) and said winding machine (A), whereon there are mounted

a first drawing carriage (20) for reel (B1) and

a second drawing carriage (21) for a flap of film (F1) of the reel (B1),

said first (20) and second (21) carriage being mounted translatable crosswise to said slidable cradle (22) and

said second carriage (21) being equipped with gripping means (27) mounted translatable according to an axis having at least a major component in a vertical direction (Z).
Wrapping system as in claim 1, wherein said first carriage (20) is equipped with an expandable shaft (25) actuated by a respective actuator (25a).
Wrapping system as in claim 1 or 2, wherein said second carriage (21) is equipped with lifting means (26) provided with a moving slider (26c) carrying said gripping means (27).
Wrapping system as in claim 3, wherein said lifting means (26) is in the shape of a pedestal (26a) which supports a linear actuator (26b) provided with said moving slider (26c).
Wrapping system as in claim 4, wherein said linear actuator (26b) is designed to cause said moving slider (26c) to shift according to a rectilinear path slightly tilted with respect to a vertical axis.
Wrapping system as in any one of the preceding claims, wherein said gripping means are in the shape of a drawing gripper (27) driven into controlled opening or closing by a respective actuator (27a).
Wrapping system as in any one of the preceding claims, wherein in the proximity of a home position of said reel-carrying unit (P), a first station actuator (7) having displacement according to a first horizontal axis (X) and a second station actuator (8) having displacement according a second horizontal axis (Y) perpendicular to said first axis (X) are provided, apt to handle an ejection fork (8a) configured to be engaged with said support shaft (4).
Reel change unit in a wrapping machine (A) employing plastic film reels (B1), characterised in that it comprises a replacement carriage (C) equipped with
at least a cradle (22) sliding on transfer rails (23), whereon there are mounted

a first drawing carriage (20) for a reel (B1) and

a second drawing carriage (21) for a flap of film (F1) of the reel (B1), and in that

said first (20) and second (21) carriage are mounted translatable crosswise to said sliding cradle (22),

said first carriage (20) is equipped with an expandable shaft (25) apt to be inserted into a core of said reels (B1), and

said second carriage (21) is equipped with gripping means (27) mounted translatable according to a second axis having at least a major component in a vertical direction (Z).