WO2000053498A1

WO2000053498A1 - A top film applicator and a method of applying top film onto a cargo

Info

Publication number: WO2000053498A1
Application number: PCT/DK2000/000103
Authority: WO
Inventors: Jan Madsen
Original assignee: Seelen A/S
Priority date: 1999-03-11
Filing date: 2000-03-10
Publication date: 2000-09-14
Also published as: AU3147700A

Abstract

The invention relates to a device for applying top film onto a cargo comprising palleted stacks of objects. The invention is characterised in that the device comprises a conveyance mechanism configured for being conveyed across the top of a still cargo while simultaneously unrolling film from a film roll; and a device for cutting off the film transversally to the unrolling direction following unrolling of the film.

Description

A top film applicator and a method of applying top film onto a cargo

The invention relates to a device for applying a top film onto a cargo comprising palleted stacks of objects as featured in the preamble to claim 1.

Top film is used when palleted cargoes are to be wrapped in stretched film in order to achieve covering of the cargo top whereby the cargo is also protected at the top where the wrapping cannot be accomplished.

Automatic top film applicators are known where the pallet with its cargo is conveyed via a transport path under- neath a top film dispenser that unwinds, during passage, a top film to the top of the cargo. Such device is described in US A 3,640,048. However, in that case there is a risk that the film will subsequently blow off due to the movement of the cargo. Moreover, it is necessary to repress large quantities of air between the top side of the cargo and the film, and this air will, in adverse conditions, act as a cushion that makes the film slide and hence be displaced on or entirely slide off the cargo .

It is the object of the invention to enable automatic application of top film onto still cargoes and to ensure that an applied film remains in its correct position.

This is obtained with a device of the kind described in the preamble to claim 1 that also possesses the particular characterising features stated in the characterising part. The conveyance mechanism enables a top film to be conveyed across a still cargo and arranged reliably thereon in such a manner that the film is arranged accurately and reliably relative to the cargo.

Thus the device comprises a utility for securing suspended portions of applied film to two or more of the cargo sides, said utility comprising movable welding units configured for external abutment on suspended por- tions of the film for welding thereof to the cargo from at least two opposed sides. Hereby a top film is obtained that is completely immovable relative to the cargo and that cannot blow off if the cargo is moved or brought into open air. Welding of the film to the cargo at two sides yields an extremely safe and reliable attachment of the film.

As stipulated in claim 2, the conveyance mechanism comprises a telescopic arm on the outside of which a clamp roller is mounted that is configured for securing and advancing top film from a roll at a stationary part of the telescopic arm, wherein a cutter is provided at the clamp roller for cutting off the top film.

This mechanism is able to function in that the telescopic arm pulls the film off a roll and across the cargo, said clamp roller being kept still and squeezing the film tightly against a retaining roller at the outermost end of the telescopic arm. Once the telescopic arm is straightened the film will extend from the roll and across the cargo. The telescopic arm is then conveyed back and in order to deposit the film on the cargo the clamp roller is caused to rotate and thus transfers the pulled-out film to the top face of the cargo. Of course it is possible to operate the clamp roller during the advancement as well as the return movement, with the result that film is transferred to a cargo both during advancement and to another cargo during return. The following transfer of film is described as occurring during the return movement only.

The roll can be arranged above or below the telescopic arm, but in order to prevent the film from colliding with the cargo during the pulling-out procedure, the film is conveniently arranged above the telescopic arm, which means that the pulled-out film is caused to initially rest on top of the arm. During withdrawal of the arm, the film is transferred from the clamp roller and down onto the cargo. When the arm is withdrawn the cutter is activated and the film is cut off and drops down onto the cargo and settles loosely thereon.

The width of the film and thus the length of the portions thereof that are suspended at the sides of the cargo are determined by the width of the roll, whereas the distance traversed by the telescopic arm determines the length of the film. Both are conveniently selected to allow an ade^¬ quate portion to be suspended at the sides and ends of the cargo.

According to the claim, the roll is arranged at a stationary part of the arm, since this is the most convenient location considering the weight of the roll, but it is possible to locate the roll at the outermost part of the telescopic arm in immediate vicinity of the clamp roller. As stated in claim 3 each welding unit is mounted to be horizontally displaceable on a common, vertically movable frame element. When no welding is going on, the frame element can be raised so as not to be in the way during preceding and subsequent operations.

According to another embodiment of the invention as featured in claim 4 the conveyance mechanism comprises a first carriage with a film roll, and a second carriage which is horizontally displaceable relative thereto and comprising a film gripper at its outermost end, said second carriage being configured for seizing a loose end of the film from the roll, and upon the horizontal displacement pull film off the roll and across the cargo, and wherein the outer end of the first carriage features a device for cutting off the unrolled piece of film.

In this embodiment, the carriage that pulls the film off the roll needs only to be fitted with a gripper and therefore it does not need to be fitted with a clamp roller or cutter which makes the carriage lighter and thus improves dynamics.

In this embodiment the first and second carriages are also advantageously and as featured in claim 5 connected to each their transversal welding device for welding of the applied top film at suspended sides thereof onto the cargo .

Positioning of the welding device on the top film applicator itself enables a very compact construction with ensuing smaller installation dimensions. As featured in claim 6, the invention also relates to a method of applying a top film onto a cargo comprising palleted stacks of objects, wherein the application is effected by conveyance of the top film by means of a con- veyance mechanism across the cargo while unwinding a top film from a roll, and application of the film onto the cargo top face and cutting off of the top film from the roll; and wherein said top film is, following application, secured at suspended portions to the outside of the cargo at least at two opposite sides.

The method ensures a reliable and swift application of top film. Following cutting-off, the film will be reliably and stably positioned while extending across the cargo and down along the sides thereof and ready for the subsequent attachment.

Furthermore, following application the top film is attached at suspended portions to the outside of the cargo at least at two opposite sides. Hereby the film is unable to shift relative to its position. The attachment can be carried out in a variety of ways, and for instance there can be self-adhesive portions of the film underside that are automatically caused to adhere to the top face of the cargo, or it is an option that prior to the application the sides of the cargo can be coated with glue. It is a further option in accordance with the invention to attach the film by means of welding. This requires that it is possible to weld the film onto the sides of the cargo, but this will often be the case.

A convenient embodiment of the method is accomplished in accordance with the teachings of claim 7 in that, prior to the top film application, the cargo is wrapped in film from the bottom and up, and that following the top film application the cargo is wrapped with film from the top and down towards the pallet. Hereby the top film is caused to be situated between two layers of wrappings and it is ensured that the mentioned welding can always be accomplished. Pallets that are wrapped in this manner tolerate storage in the open, albeit the cargo itself does not tolerate water.

In the following, an embodiment of the invention is described with reference to the drawings, wherein

Figure 1 schematically represents the applicator, seen from the side with the arm in its extended position;

Figure 2 the applicator following withdrawal of the arm and cutting-off of the film;

Figure 3 illustrates an exemplary embodiment of the weld- ing unit; and

Figures 4 through 8 illustrate the stepwise order of application of top film by use of a top film applicator in accordance with an alternative embodiment of the inven- tion.

Figures 1 through 3 illustrate a top film applicator. It comprises a telescopic arm 20 that pulls the top film 21 off a roll 22 and across the pallet cargo 19. In the case shown this is accomplished when a first layer of wrappings has shrouded the cargo 19. At the extremity of the telescopic cam 20, an advance roller 25 and a cutter 23 are arranged. When the arm 20 is extended across the cargo 19, the roller 22 advances additional film that can be suspended over the pallet side. The arm 20 is subsequently withdrawn while simultaneously the roller 25 is rotated such that the film that was previously situated on top of the arm 20 as shown in Figure 1 is now posi- tioned on top of the cargo 19 as shown in Figure 2. Finally a cutter 23 is activated to cut off the film to enable onset of a renewed cycle.

The shown example of a conveyance mechanism can be changed in a variety of ways within the scope of the invention. For instance, the roll 22 can be mounted on a carriage that is conveyed on rails across the cargo in such a manner that the roller 25 actively unwinds film during passage of the carriage in the one direction across the cargo, and wherein the cutter 23 is subsequently activated.

Now, Figure 3 shows the subsequent welding operation wherein the top film 21 is welded firmly onto two sides of subjacent cargo 19. Herein this is accomplished by two welding beams being conveyed down to the level where the welding is desired, and then for a certain period of time tit they clamp the suspended portions of the film firmly towards the cargo 19 while the welding beam 24 is heated to the welding temperature. During the welding procedure, the plate 9 of the pallet holder holds the film tightly towards the top face of the cargo 19. It is possible to attach the top film in other ways, for instance glue can be used which is applied to the cargo sides prior to ap- plication of the top film. According to a further exemplary embodiment, the film can be self-adhesive on some parts of its underside, or glue can be applied to the underside of the rim portions of the film during application. Figure 3 also shows a pallet lift 26 that can be used during the wrapping procedure to raise the pallet from the support such that the wrapping can be started on the pallet to ensure adequate connection between the pallet and the cargo .

In accordance with the embodiments shown in Figures 4 through 9, the top film applicator is fitted with a first horizontally displaceable carriage 31 and a second carriage 30 that is horizontally displaceable relative thereto. The roll 22 is fitted on the first carriage 31, and the film 21 is conveyed around a turning roller 32 at the underside of the first carriage 31 and onwards to a film gripper and holder 33 at the underside of the extreme end of the second carriage 30.

In the first step of the application process, the second carriage 30 is moved forwards relative to the first car- riage 31 to a position above the cargo 19 as shown in Figure 5. Here the holder 33 secures the film whereby the film 21 is pulled off the roll 22 and is caused to be positioned at the underside of the second carriage 30. As will appear from Figure 6, the film is subsequently cut off at the extreme end of the first carriage 31 by means of a cutter 34 while simultaneously the holder 33 lets go of the film. The top film sheet 21 now cut off will subsequently drop down to rest on top of the cargo 19 with film portions suspended along the sides of the cargo 19.

Figures 7 and 8 show how the welding is now performed. At the extremity of the second carriage 30 a holder 28b is hinged to a welding beam 24, and this holder is positioned by conveying the carriage a further distance for- wards than required for application of the film, and then swinging the holder 28b down to vertical position about the hinge 27b. The swinging movement is shown by the arrow 29b. At the extreme end of the first carriage 31 a hinge 27a is also provided for connection of a holder 28a for a welding beam 24. This is also configured for being pivoted down into a welding position in the direction of the arrow 29a following advancement of the first carriage 31 to a position in which the welding can be performed as shown in Figures 7 and 8. As will appear from Figure 8, the two welding beams are clamped against the suspended parts of the top film, either by the swinging movement of the holders' 28a and 28b or by a slight displacement of the carriages 30 and 31 relative to each other.

By this embodiment, the integral construction of the top film applicator and the welding unit accomplishes a very compact configuration of the mechanism.

Herein suitable actuators that are convenient for this purpose perform the various movements.

Claims

C l a i m s

1. A device for the application of top film 21 onto a cargo 19 comprising palleted stacks of objects, said de- vice comprising a conveyance mechanism (20,20; 30; 31) configured for being conveyed across the top of a still cargo (19) while simultaneously unrolling film (21) from a roll of film (22) and a device for cutting off the film (21) transversally to the direction of unrolling follow- ing unrolling of the film (21), characterised in that a device (24) is provided for attaching suspended portions of the applied film to two or more of the cargo sides, said device comprising movable welding units (24) configured for external abutment against suspended portions of the film (21) for welding thereof onto the cargo (19) at least from two opposed sides.

2. A device according to claim 1, characterised in that the conveyance mechanism (20,21) comprises a telescopic arm (21) at the outer end of which a clamp roller (25) is mounted that is configured for securing and advancing top film (21) from a roll (22) at a stationary part (22) of the telescopic arm; and in that a cutter (23) is provided at the clamp roller (25) for cutting off the top film (21) .

3. A device according to claim 1, characterised in that each welding unit (24) is mounted to be horizontally displaceable on a common vertically movable frame element.

4. A device according to claim 1, 2 or 3, characterised in that the conveyance mechanism comprises a first carriage (31) with a film roll (22), and a second carriage (30) that is horizontally displaceable relative thereto with a film gripper (33) at the outer end, said other carriage (30) being configured for seizing a loose end of the film (21) from the roll (22) and by the horizontal displacement pulling film (21) off the roll (22) and across the cargo (19) ; and wherein the outer end of the first carriage (31) is provided with a device (34) for cutting loose the unrolled piece of film (21) .

5. A device according to claim 4, characterised in that the first and second carriages (30,31) are connected to each their transversal welding device (24) for welding of the applied top film (21) onto the cargo (19) at suspended sides thereof.

6. A method of applying top film (21) onto a cargo (19) comprising palleted stacks of objects, whereby the application is accomplished by conveyance of the top film by means of a conveyance mechanism (20, 21; 30, 31) across the cargo (19) while unrolling top film (21) from a roll (22) and deposition of the film (21) onto the top face of the cargo and cutting loose the top film from the roll, said application being performed by conveyance of the top film with a conveyance mechanism (20, 21; 30; 31) across the cargo (19) while unrolling top film (21) from a roll (22) and deposition of the film (21) to the top face of the cargo and cutting loose the top film from the roll, and wherein the top film (21) is, following application, attached at suspended portions to the outside of the cargo (19), at least at two opposite sides.

7. A method according to claim 6, characterised in that prior to the top film application, the cargo (19) has been wrapped in film from the bottom and up, and wherein the cargo (19) is, following top film application, wrapped in film from the top and down towards the pallet.