WO2012153285A1

WO2012153285A1 - Wrapping apparatus

Info

Publication number: WO2012153285A1
Application number: PCT/IB2012/052319
Authority: WO
Inventors: Mauro Cere'
Original assignee: Aetna Group S.P.A.
Priority date: 2011-05-10
Filing date: 2012-05-09
Publication date: 2012-11-15
Also published as: ITMO20110107A1

Abstract

An apparatus that is associable with a machine for wrapping a load (30) with a film (50) of plastics, comprises supporting means (2) to support a reel (3) of the film (50), roller means (4, 5) for unwinding and prestretching the film (50) and a guiding roller (10; 20) for engaging and diverting to the load (30) the film (50) leaving the roller means (4, 5); the guiding roller (10; 20) is rotatably mounted on the supporting means (2) such as to be tiltable by a tilt angle (a) with respect to rotating axes (Al, A2) of the roller means (4, 5); the guiding roller (10; 20) comprises a plurality of rings (11, 12; 21, 22) spaced along a longitudinal axis (X) of the aforesaid guiding roller (10; 20), the latter, when tilted, reducing a width (LI; L2) of a strip (50A; 50B) of said film (50) wrapped around the load (30), the rings (11, 12; 21, 22) engaging the film (50) and making longitudinal pleats (51) thereupon.

Description

Wrapping apparatus

The invention relates to apparatuses and machines for wrapping a load with a film or pellicle of cold-stretchable plastics. In particular, the invention relates to an apparatus that is installable on a wrapping machine for unwinding, prestretching and selectively shrinking a width or breadth of a strip of a film of stretchable plastics to be wrapped around a load to be packaged.

Wrapping apparatuses are known that are mounted on wrapping machines and support a reel from which the film of plastics is unwound to be wrapped around the load such as to form a series of helically bound strips or bands, owing to the combination of movement in a vertical direction of the wrapping apparatus and of the relative rotation between the latter and the load. The latter typically consists of one or more products grouped and arranged on a bench or vane or pallet .

In wrapping machines provided with a rotating table supporting the load, the latter is rotated around a vertical wrapping axis, whereas the wrapping apparatus is moved vertically with reciprocating motion along a fixed column of the machine .

In ring or rotating arm wrapping machines, the product remains stationary during wrapping whilst the wrapping apparatus, fixed to the ring or to the rotating arm, is moved with respect to the latter both to rotate around the vertical wrapping axis and to move parallel to the latter.

The wrapping apparatus typically comprises a carriage that supports the reel of film as well as a pair of prestretching rollers arranged for unwinding the film from the reel and prestretching or elongating the film and one or more idler rollers for diverting the film to the load. By suitably adjusting the difference between the rotation speed of the prestretching rollers, it is possible to prestretch the film by a defined amount or percentage and/or vary the unwinding speed of the film from the reel. The elongation both enables the film to be used as best as possible (the reduction of the thickness of the film enables the length thereof to be increased so as to wrap a greater number of products) and enables the mechanical features of the material to be changed in function of the product to be wrapped (to obtain elastic or plastic elongation of the material) .

The film of plastics is wrapped in such a manner as to bind the load completely on all sides.

In order to stabilise the load when it is arranged on a pallet it is also necessary to wrap the film around a base of the load and an upper portion of the pallet. If this were not done the load could move dangerously with respect to the pallet during wrapping and/or subsequent transport.

In order to ensure suitable tension to the film and to ensure that the film has greater resistance to the traction forces that originate, for example, from shifts or movements of the load, rolling the film completely or partially is known so as to reduce a width or breadth of a strip or band and at the same time make at least one cord or cable of film to be wrapped tightly around the load and the pallet. The cord, which is obtained by progressively wrapping or rolling on itself a longitudinal edge of the film, in fact enables greater wrapping or tensioning force to be obtained than with a whole strip or band film. The film that is rolled into a cord is also used to stabilise and reinforce better the parts of the load that are more unstable .

For this purpose, different devices or mechanisms are known that are applicable to the wrapping apparatuses and are able to roll one or both the longitudinal edges of the film exiting the wrapping apparatus.

A drawback of wrapping with film rolled into a cord consists of the fact that as the cord is substantially stiff and wrapped with conspicuous tensioning force to stabilise and reinforce the load properly it can deform the load in the zones of contact or tightening, in particular if the load consists of deformable or yieldable products. Such deformations can damage and ruin the load and/or the products .

Another drawback of wrapping with film rolled into a cord consists of the fact that the aforesaid cord has to be "reopened" , by recomposing the strip of film substantially in the original width or breadth thereof in order to be able to terminate wrapping of the load and fix, in particular weld, the film.

As known in fact, at the end of wrapping the portion of film comprised between the wrapping apparatus and the load has to be cut. Of the two end flaps generated by the cut, one is fixed, welded or glued to a wall of the bound load and the other is grasped and retained by a gripping device of the machine to permit wrapping of the subsequent load.

The process of reopening the cord is not only laborious and complex but also requires an additional quantity of film to make the end fixing flap.

The wrapping apparatuses provided with mechanisms for forming the cord and reopening the cord are very complex, bulky and costly.

An object of the invention is to improve known wrapping apparatuses that are associable with wrapping machines and are arranged for unwinding and prestretching a film of plastics .

Another object is to make a wrapping apparatus that enables a width or breadth of a strip of the film of plastics to be varied simply, rapidly and effectively during wrapping thereof around the load, in particular in function of a structure and/or composition of the aforesaid load.

A further object is to obtain a wrapping apparatus that enables a width of the strip of the film wrapped on the load to be reduced, at the same time making thereupon a plurality of longitudinal pleats or folds to exert great wrapping force on the load and to bestow great stability to the latter.

Still another object is to make a wrapping apparatus that enables a base of the load to be wrapped effectively and tightly on a bench or supporting pallet to stabilise the aforesaid load.

A still further object is to make a wrapping apparatus that enables the film to be fixed easily and effectively to the load at the end of wrapping.

A still further object is to make a wrapping apparatus having a relatively cheap and simple construction.

Such objects and still others are achieved by a wrapping apparatus according to one or more of the claims set out below.

The invention can be better understood and implemented with reference to the attached drawings that illustrate some embodiments thereof by way of non limiting example, in which: Figure 1 is a frontal view of a wrapping apparatus according to the invention associated with a rotating arm wrapping machine, which is partially illustrated, and comprising a guiding roller arranged in a tilted wrapping operating position of a film around a load;

Figure 2 is a plan view of the apparatus and of the machine in Figure 1;

Figure 3 is an enlarged frontal view of the wrapping apparatus in Figure 1 in which the film is diverted downwards to show better the longitudinal pleats or folds made thereupon by the guiding roller;

Figure 4 is a view like the one in Figure 3 in which the guiding roller is arranged in an erect wrapping operating position;

Figure 5 is an exploded view of the wrapping apparatus in Figure 1 ;

Figure 5b is an enlarged view of a detail in Figure 5 showing in particular rings of the guiding roller;

Figure 6 is a frontal view of the wrapping apparatus in Figure 1 fixed to the wrapping machine in a different mounting position;

Figure 7 is an enlarged frontal view of a version of the wrapping apparatus in Figure 1; Figure 8 is an exploded partial view of the wrapping apparatus in Figure 7.

With reference to figures 1 to 6, an unwinding apparatus 1 is illustrated that is associable with a wrapping machine 100, for example provided with a vertical rotating arm 101 and arranged for wrapping with a film or pellicle 50 of stretchable plastics a load 30 comprising, for example, a plurality of products arranged on a pallet.

The apparatus 1 is mounted on connecting means 102 that is movable along the vertical arm 101 that is rotatable around a wrapping axis Z. The load 30 is arranged on a roller conveyor 103 of the wrapping machine 100.

The wrapping apparatus 1 of the invention can also be mounted on a vertical or horizontal ring wrapping machine, or on a wrapping machine with a rotatable platform and a vertical support column.

The wrapping apparatus 1 comprises supporting means 2 for rotatably supporting a reel 3 of film 50, roller means 4, 5 for unwinding and prestretching the film 50 and a guiding roller 10 for engaging and diverting to the load 30 the film 50 exiting the roller means 4, 5 and wrapping around the aforesaid load 30.

The roller means comprises a first prestretching roller 4 and a second prestretching roller 5 cooperating for unwinding and prestretching the film 50. The prestretching rollers 4, 5 are rotated around respective longitudinal axes, for example, by respective motors, which are not illustrated in the figures. The first, so-called fast, roller 4, which is located downstream of the second, so-called slow, roller 5, with respect to the movement of the film 50, rotates faster than the second roller 5 to enable the film 50 to be prestretched by a defined amount or percentage.

Further idler rollers 6, 7, 8 are provided for diverting the film 50 from the reel 3 to the first roller 4 and to the second roller 5 and from the first roller 4 and to the second roller 5 to the guiding roller 10. The guiding roller 10 is mounted rotatably on the supporting means 2 so as to be tiltable by a set tilt angle a with respect to rotating axes Al, A2 of the roller means 4, 5. In particular, the guiding roller 10 is mounted on a supporting element 15 that is rotatably fixed to the supporting means 2. The supporting element 15 is rotatable around an axis that is transverse, in particular orthogonal, to a longitudinal axis X of guiding roller 10 that is thus tiltable.

The guiding roller 10 is mounted on the supporting element 15 that is idle, i.e. free to rotate around the longitudinal axis X.

Driving means 16 is fixed to the supporting means 2 and acts on the supporting element 15 to rotate the latter and thus adjust the tilt angle a of the guiding roller 10. The driving means 16 comprises, for example, a linear actuator of pneumatic, or hydraulic or electric type.

The guiding ring 10 comprises a plurality of rings 11, 12 that are spaced apart from one another along the longitudinal axis X of the guiding roller 10 and arranged for engaging and retaining the film 50 in a direction that is parallel to the aforesaid longitudinal axis X such as to make longitudinal pleats 51 thereupon.

As explained better below in the description, when the guiding roller 10 is tilted it reduces a width or breadth or height of a strip of the film 50 wrapped on the load 30. The rings 11, 12 retain the film 50 preventing the sliding thereof along the guiding roller 10 and make longitudinal pleats 51 on the film.

In the illustrated embodiment, the guiding ring 10 comprises first rings 11 and second rings 12 having the same diameter but different lengths. In particular, the length of the first rings 11 is less than a length of the second rings 12.

Each first ring 11 and second ring 12 comprises a tubular or annular cylindrical body provided with rounded or shaped edges or corners 11a, 12a. In particular, the rounded edges 11a, 12a connect a cylindrical side wall lib, 12b of the body to respective flat end faces 11c, 12c of the aforesaid body. The rings 11, 12 are made, for example, of plastics.

The first rings 11 and the second rings 12 are mounted or splined on a shaft 13, the number, arrangement and reciprocal spacing (distribution) thereof along the shaft 13 being determined in function of the features of the film 50 (type of plastics, thickness, mechanical resistance, etc.) and/or of a prestretching percentage to be given to the film by the roller means 4, 5 during wrapping.

With reference to the embodiment illustrated in figures 1 to 6 merely by way of non limiting example, the guiding roller 10 comprises four first rings 11 and six second rings 11. It is provided for that the guiding roller 10 can comprise rings having different lengths and the same diameter or comprise only rings having the same length and diameter.

Opposite ends of the shaft 13 are rotatably fixed to brackets 17, 18 of the supporting element 15 comprising, for example, a U-shaped section. In this manner the shaft 13 and thus the rings 11, 12 are free to rotate around the longitudinal axis X of the guiding roller 10.

The supporting means 2 is rotatably fixed to connecting means 102 of the wrapping machine 100, to enable a further tilt angle β of the apparatus 1 to be adjusted with respect to the wrapping axis Z.

As explained in greater detail further on in the description, by tilting the wrapping apparatus 1 suitably, for example by an angle of 15° as in the operating configuration Wl illustrated in figures 1 to , it is possible to divert the film 50 to a lower portion of the load 30 and, if present, an upper portion of a pallet on which said load 30 is deposited. The connecting means 102 comprises a plate that is movable along the vertical arm 101.

The operation of the wrapping apparatus 1 of the invention provides rotation of the vertical arm 101 around the wrapping axis Z and rotation of the first roller 4 and of the second roller 6 to unwind the film 50 from the reel 3 and prestretch the film 50 by a set amount or percentage.

At the beginning of wrapping, the guiding roller 10 can be arranged in an erect operating position E (Figure 4) in which it is parallel to the rollers 4, 5 (with the tilt angle a equal to 0°) and in which it engages the film 50 without causing any shrinking thereof . In this erect operating position E a width or height of the strip or band of film 50 that wraps the load 30 is substantially the same as the width L of the film 50 wrapped on the reel 3.

By tilting the guiding roller, imposing a set value of the tilt angle a, it is possible to reduce the height of the strip 50A of the film 50.

In a tilted operating position B (Figure 1) the tilt of the longitudinal axis X of the guiding roller 10 determines, in fact, traction forces that are transverse to the unwinding direction of the film 50 and are directed to the lower portion of the guiding roller 10 that is nearer the supporting means 2. These forces tend to move and slide the film 50 along the guiding roller 10 and in the absence of the rings 11, 12 would cause the complete shrinkage of the film 50 that, by rolling and/or folding, would form a cord or cable. The rings 11, 12, which are suitably arranged and spaced, prevent the film 50 being able to run or slide along the guiding roller 10, forming, also partially, a cord. In particular, the edges 11a, 12a of the rings 11, 12 retain the film 50 and at the same time they interact with the latter to make corrugations or pleats 51 that, once the film 50 has disengaged from the guiding roller 10, determine the desired shrinkage of the film 50. In other words, owing to the rings 11, 12 and to the transverse forces that are generated by tilting the guiding roller 10, the film 50 exits the wrapping apparatus 1 of the invention with a plurality of longitudinal pleats 51 that form a sort of crimping that reduces the width thereof .

By choosing suitably the number of the first rings 11 and the second rings 12 and reciprocally positioning and distributing the aforesaid rings 11, 12 along the longitudinal axis X, it is possible to obtain longitudinal pleats 51 that are otherwise distributed and made on the film 50.

The longitudinal pleats 51 and the tilt of the guiding roller 10, and thus of the film 50, enable the height LI of the strip 50A of the film 50 wrapped on the load 30 to be reduced.

With high values of the tilt angle a of the guiding roller 10 (70-80°) it is possible to shrink significantly this strip height LI (by as much as a few centimetres) and to bind the load 30, conferring greater stability to the latter, since, as known, a strip of film of limited or "shrunk" height enables greater wrapping or pulling force on the load to be obtained.

At the same time, a shrunk strip of film, unlike rolled cords or ropes of film, enables pressure to be distributed better on the application or contact zones of the load, avoiding deformation and/or breakage and damage thereto.

The film with a shrunk and pleated strip 50A can also be easily and effectively welded at the end of the wrapping cycle with a contrast welding process without requiring the strip 50A to be "reopened", i.e. stretched or unfolded. Further, by reducing the height of the strip 5OA it is possible to use a contrast 19 of small dimensions (Figure 1) . By suitably tilting the wrapping apparatus 1 in relation to the vertical rotating arm 101, for example such that the further tilt angle β is equal to 15°, it is moreover possible to divert the film 50 with a shrunk strip 50A to a lower portion of the load 30 and, if present, an upper portion of a pallet on which said load 30 is deposited (Figure 1) . In this manner it is possible to stabilise in an optimum manner the load 30 with respect to the pallet.

Figure 6 illustrates a further operating configuration W2 of the wrapping machine 100 in which the wrapping apparatus 1 is not tilted with respect to the vertical rotating arm (the further angle β is equal to 0°) and the film 50 wraps on the load 30 with a strip 50B having a different height L2.

Figures 7 and 8 illustrate a version of the wrapping apparatus 1 of the invention that differs from the embodiment disclosed above for the guiding roller 20 that comprises a plurality of further first rings 21 and of further second rings 22 that are spaced apart from one another along the longitudinal axis X. The further first rings 21 differ from the further second rings 22 in length and diameter.

Each further first ring 21 is substantially similar to the first ring 11 of the wrapping apparatus disclosed previously and illustrated in figures 1 to 6, and comprises a tubular or annular cylindrical body that is placeable over the shaft 13, possibly provided with rounded edges or corners.

Each further second ring 22 comprises a hub 22a that is placeable onto the shaft 13 and a disc 22b of substantially cylindrical shape. The hub 22a and the disc 22b are made, for example, of a single body made of plastics. The diameter of the disc 22b is greater than the diameter of the hub 22a. The diameter of the hub 22a is substantially the same as the diameter of the tubular body of the first ring 21; the length thereof is, for example, greater than that of the tubular body of the first ring 21.

Also in this embodiment of the apparatus 1, the number of the rings 21, 22, the arrangement and mutual distance thereof or distribution along the shaft 13 are determined in function of the features of the film 50 (type of plastics, thickness, mechanical resistance, etc) and of a prestretching percentage to be given to the film 50 by the roller means 4, 5 during wrapping. The rings 21, 22, which are suitably arranged and spaced apart, prevent the film 50 being able to run or slide along the guiding roller 10, forming, also partially, a cord. In particular, the discs 22b of the further second rings 22 retain and block the film 50 by making marked corrugations or pleats 51 on the film 50 once it disengages from the guiding roller 10.

With reference to the embodiment illustrated in figures 7 and 8 merely by way of non-limiting example, the guiding roller 10 comprises six further first rings 21 and four further second rings 12.

It is also provided for that the guiding roller 10 can be provided with further rings of different diameter and/or of different length.

Claims

Apparatus, associable with a machine for wrapping a load (30) with a film (50) of plastics, comprising supporting means (2) for supporting a reel (3) of said film (50) , roller means (4, 5) for unwinding and prestretching said film (50) and a guiding roller (10, 20) for engaging and diverting to said load (30) said film (50) leaving said roller means (4, 5), characterised in that said guiding roller (10; 20) is rotatably mounted on said supporting means (2) so as to be tiltable by a tilt angle (a) with respect to rotating axes (Al, A2) of said roller means (4, 5), said guiding roller (10, 20) comprising a plurality of rings (11, 12; 21, 22) spaced along a longitudinal axis (X) of said guiding roller (10, 20) , said guiding roller (10, 20) when tilted reducing a width (LI; L2) of a strip (50A; 50B) of said film (50) wrapped around said load (30), said rings (11, 12; 21, 22) engaging said film (50) and making longitudinal pleats (51) thereupon.

Apparatus according to claim 1, wherein said guiding roller (10, 20) is mounted free to rotate around said longitudinal axis (X) on a supporting element (15) , the latter being rotatably fixed to said supporting means (2) such as to tilt said guiding roller (10, 20) of said tilt angle (a) .

Apparatus according to claim 2, comprising driving means (16) fixed to said supporting means (2) and acting on said supporting element (15) to change and/or adjust said tilt angle (a) of said guiding roller (10, 20) .

Apparatus according to claim 2 or 3 , wherein said rings (11, 12; 21, 22) are mounted on a shaft (13) that is rotatably supported by said supporting element (15) .

Apparatus according to any preceding claim, wherein said rings are the same each other and have the same diameter and length.

Apparatus according to any one of claims 1 to 4 , wherein said guiding roller (10) comprises at least a first ring (11) and at least a second ring (12) having the same diameter and different lengths.

Apparatus according to claim 5 or 6, as appended to claim 4, wherein each ring (11, 12) comprises a cylindrical tubular body that is insertible into said shaft (13) and has edges (11a, 12a) , said edges (11a, 12a) being suitable for interacting with said film (50) so as to make said longitudinal pleats (51) on said film (50) .

Apparatus according to any one of claims 1 to 4 , wherein said guiding roller (20) comprises at least a further first ring (21) and at least a further second ring (22) having the same length and different diameters.

Apparatus according to claim 8, as appended to claim 4, wherein each further second ring (22) comprises a hub (22a) that is insertible into said shaft (13) and a disc (22b) having a substantially cylindrical shape and suitable for engaging said film (50) , in particular said hub (22a) and said disk (22b) being made in a single body and of plastics.

Apparatus according to any preceding claim, wherein a number of said rings (11, 12; 21, 22) and an arrangement thereof along said guiding roller (10, 20) are correlated to features of said film (50) and/or to a prestretching percentage to be made on said film by said roller means (4, 5) during wrapping of said load (30) .

Apparatus according to any preceding claim, wherein said supporting means (2) is rotatably fixed to connecting means (102) of said wrapping machine (100) for orienting said apparatus (1) with respect to a wrapping axis (Z) of said film (50) around said load (30) , in particular for adjusting a further tilt angle (β) of said apparatus (1) with respect to said wrapping axis (Z) .

Machine for wrapping a product (30) with a film (50) of plastics comprising an apparatus (1) according to any preceding claim.