WO2003043916A1

WO2003043916A1 - Method and arrangement for palletizing cylindrical objects

Info

Publication number: WO2003043916A1
Application number: PCT/SE2002/002124
Authority: WO
Inventors: Weine AGNÉ
Original assignee: Nordisk Plåtindustri Benetec Ab
Priority date: 2001-11-22
Filing date: 2002-11-22
Publication date: 2003-05-30
Also published as: EP1453749A1; AU2002366112A1

Abstract

A method and an apparatus for loading cylindrical objects onto a load carrier, such as pallets, is described. Said method and apparatus are particularly suitable for palletising tubular goods, such as packages of can lids. The apparatus comprises means for arranging the objects side by side in layers on the load carrier, and a plurality of such layers on top of each other, and means for laying out a locking material in a loop between the layers. It further comprises at least one load directing means, which during loading is displaceable toward and away from the loaded objects in a direction which is essentially parallel to the axial direction of objects.

Description

METHOD AND ARRANGEMENT FOR PALLETISING CYLINDRICAL OBJECTS

Field of the Invention

The present invention relates to a method and an apparatus for loading cylindrical objects onto a load carrier. The invention is particularly suitable for palletising tubular goods, such as packages of can lids. Background Art

Packaging of elongated, cylindrical objects, i e objects whose diameter is considerably smaller than their length, and whose diameter also is considerably smaller than the dimensions of the load carrier, usually involves placing the objects side by side in the same direction and then stacking them in a plurality of layers on the pallet or any other load carrier. However, to secure the objects to the pallet the goods have to be locked in their position in some way so as not to fall off the pallet .

One way to secure and lock the objects onto the pallet as desired is to lay a band of paper or any other film material in loops on and around the objects.

US 4,537,010 discloses an example of such a prior-art method and apparatus for arranging two bands in loops in the goods being loaded. The applicant behind the present application has previously also developed a method and an arrangement for locking the loaded objects by means of a single loop, as disclosed, for example, in US 5,769,601. By laying out the locking strip according to a pattern while loading, the goods are locked in position on the pallet or any other type of load carrier in a manner that ensures stability and transportability and efficient volume utilization. However, these prior-art solutions are relatively complex and expensive. Furthermore, the loaded material is not always satisfactorily locked, in particular when stacking high pallets requiring a high degree of vertical alignment. In addition, special and complex measures are often needed, such as laying the locking material in one or more supplementary loops (interlocking) in the locking layer. In many cases of prior art, this is necessary to allow automated unloading of a load carrier. Arranging the first layer on the load carrier in accordance with prior art may also cause a problem if a goods object is unsymmetrical causing the goods to roll to the side where they block the next package. This problem has been solved by using a separate tool which is placed on the pallet and secured thereto before the pallet is fed to the palletising equipment, but this inevitably makes the loading process more complicated. Moreover, continuously monitoring the tension of the locking material according to prior art to ensure safe and adequate loading is complicated. In this context, switching from one completed layer to the next layer above is particularly complicated. Object of the Invention

An object of the present invention is therefore to provide an improved apparatus for loading elongated, essentially cylindrical objects onto a load carrier, i e palletising equipment.

This object is achieved by the invention as defined by the claims . Summary of the Invention

A first aspect of the invention relates to an apparatus for loading elongated, essentially cylindrical objects onto a load carrier, comprising means for arranging the objects side by side in layers on the load car- rier, and a plurality of such layers on top of each other, and means for laying out a locking material in a loop between the layers. The apparatus further comprises at least one load directing means, which during loading is displaceable towards and away from the loaded objects in a direction which is essentially parallel to the axial direction of said objects. The above apparatus allows full control during loading to be obtained, thus alleviating, if not eliminating, the problems stated above. This is made possible by the fact that the load directing means can be temporarily displaced towards loaded objects to support and stabilise them during loading of additional objects.

After loading one or several objects the load directing means can be retracted.

Preferably, the load directing means is displaceable between a load directing position and a waiting position, the load directing means being inserted, in the load directing position, in a position above the loaded objects. This allows greater stability and support, since the engagement of the load directing means with the loaded objects is thus improved. Furthermore, it is preferred for the load directing means to exert a force on the load carrier in the load directing position. The layers already loaded are thus compressed and stabilised during the continued loading of layers.

Advantageously, the load directing means may further comprise a plurality of arms oriented towards the loaded objects, and preferably at least the same number of arms as the number of objects to be loaded in each layer, the objects being arranged between pairs of adjoining arms during loading. In a preferred embodiment, the number of arms exceeds by one the number of objects to be loaded in each layer. This allows the load directing means to guide and stabilise the layer being loaded or the preceding layer by forming a support for the most recently loaded objects, which prevents these objects from rolling to the side or moving sideways in any other manner. In this case, the objects are thus placed in the compartments formed by the adjoining arms. It is particularly pre- ferred for the load directing means to accompany the movement of the load carrier. This allows stabilisation and support to be provided also when switching between different layers and full control to be maintained also when handling the outermost packages during the sensitive phase of lowering the pallet a level .

Moreover, it is preferred for one load directing means to be arranged on each side of the loaded objects, said load directing means being moved respectively to- wards and away from each other. This ensures stabilisation of both ends of the loaded objects, which increases the overall stability.

A second aspect of the invention relates to a method for loading cylindrical objects onto a load carrier, com- prising the steps of arranging elongated, essentially cylindrical objects side by side in layers on the load carrier, and a plurality of such layers on top of each other, and laying out a locking material in a loop between the layers. The method further comprises the step of inserting a load directing means, prior to loading a new layer, so that the new layer is at least partly loaded onto said load directing means, and retracting the load directing means after loading said layer. Advantages corresponding to those described above are thus obtained. According to a third aspect of the invention, it concerns an arrangement for directing the load in connection with automated loading of elongated, essentially cylindrical objects onto a load carrier, and comprises at least one load directing means, which during loading is displaceable towards and away from the loaded objects in a direction which is essentially parallel to the axial direction of said objects.

Further advantages and features of the invention will appear from the following detailed description of the invention. It should be noted that the invention is not limited to the examples of embodiments thereof provided in this description. Brief Description of the Drawings

Fig. 1 is a side view of part of a loading apparatus according to an embodiment of the invention illustrating how a first layer of cylindrical objects is loaded. Fig. 2 is a side view of the loading apparatus in Fig. 1 illustrating how subsequent layers of cylindrical objects are loaded.

Fig. 3 is a top view of the loading apparatus in Fig. 1. Fig. 4 is a side view of a pallet on which cylindrical objects are stacked in layers in accordance with the invention.

Fig. 5 illustrates a general loading apparatus according to one embodiment of the invention, in which the load directing means have not been inserted. Description of Preferred Embodiments

One embodiment of an apparatus according to the invention is shown schematically in Figs 1-3 and Fig. 5. The apparatus is intended for loading elongated, essen- tially cylindrical objects onto load carriers, such as conventional pallets. For instance, the invention may be used in the brewing industry and the food manufacturing industry to load packages of can lids. In most cases, neither the can lids nor the cans are manufactured at the site where the cans are filled and closed. To facilitate the handling of these can lids it is important that they be packed and loaded properly. For these purposes, can lids have traditionally been packed in long bags, the circumference of which is only slightly greater than that of the can lids.

Thus, the apparatus is suitable for loading essentially cylindrical objects. Here, cylindrical does not mean only circular in cross section, but various forms of angular cross sections are also possible. Furthermore, the objects should be elongated, i e have a length that is considerably greater than the diameter, since such objects are loaded in a horizontal position. It is fur- ther preferred for the objects to be loaded to have a diameter that is considerably smaller than the length or width of the load carrier. The load carrier may be, for example, a conventional pallet, but other types of load carriers are also conceivable.

The apparatus comprises means for arranging the objects side by side in layers on the load carrier 5, means for arranging a plurality of such layers on top of each other, and means for laying out a locking material in a loop between the layers. This allows the provision of loaded pallets on which the cylindrical objects 6 are stacked in layers, as shown in Fig. 4. Advantageously, the layers of cylindrical objects may be mutually displaced to obtain a more stable loading and more efficient volume utilisation. Preferably, the layers are offset by approximately half the diameter of the cylindrical objects relative to the adjacent layers.

The general design of the means for arranging the objects in layers and the means for laying out the lock- ing material may, for example, be the design used in the earlier system disclosed by the applicant in US Patent Specification No. 5,769,601, which is incorporated herewith by reference. One example of such an apparatus is shown in Fig. 5. The means for stacking the objects in layers may, for instance, comprise a displaceable, programmable pickup arm 10 provided with gripping means 11, which fetches the objects from a predetermined position and moves them to a second preprogrammed position on the load carrier. Moreover, during loading the load carrier may be arranged on a vertically adjustable lifting platform 12. It may, for instance, be supported on a vertically continuously adjustable stand 13. The lifting table here supports the pallet 5 on which the cylindrical objects are to be placed. This allows the uppermost layer in- tented for loading to be kept at essentially the same level at all times. Furthermore, the means for laying out the locking material may comprise a paper or film roll holder 14, which is coordinated with the movement of the pick-up arm so that the locking material is layed out between the cylindrical objects according to a pre- determined pattern, and any supplementary cutting equipment to cut the locking material dispensed from the roll when the loading of the pallet is completed.

However, it will be appreciated that many variants and modifications are possible to achieve similar loading functions and that this is not crucial to the realisation of the invention. Therefore the scope of the invention is not limited to the embodiment described above.

The apparatus further comprises at least one load directing means, which during loading is displaceable towards and away from the loaded objects in a direction which is essentially parallel to the axial direction of said objects. Preferably, however, one load directing means is arranged on each side of the objects being loaded. One embodiment of such a load directing means is shown in detail in Figs 1-3.

The load directing means may comprise, for example, two parallel, preferably vertically disposed guides 10, a transverse girder 11 being mounted in the lower part thereof. Horizontally guided girders 12 are mounted at both ends of said girder and connected at their front ends to a transverse guide 13. A girder 14 having shafts or arms 15 (fork unit) is mounted on said guide 13. Preferably, the load directing means comprises at least the same number of arms as the number of objects to be loaded in each layer, so that during loading the objects can be arranged between pairs of adjoining arms. The girder provided with shafts (fork unit) is adapted, in terms of shaft diameter and centre-to-centre distance, to accommodate the package dimension of the cylindrical objects. The guides can be moved by means of pneumatic cylinders 20-22, in which case the vertical cylinder is preferably provided with a pressure regulator to allow the vertical force to be controlled. Moreover, the lateral movement of the fork unit may be adapted to the package being loaded and amounts in the case of round objects to half their diameter. To ensure safe operation when the forks are retracted axially from their position in the pallet and returned to the starting position used for the next layer, the fork unit may be provided with a locking unit which mechanically blocks the vertical movement.

A load directing means which is displaceable between a load directing position and an inactive position is thus obtained, the load directing means being inserted, in the load directing position, in a position above the loaded objects. Moreover, the load directing means is preferably adapted to exert a force, in the load di- recting position, in the direction of the load carrier, here downwards .

During loading, a pallet or any other load carrier 5 is brought into the position of loading of the first layer by means of the lifting table 12. During this op- eration, the load directing means are suitably in their inactive waiting position, which may be, for example, raised and retracted to a position away from the load carrier. Once the pallet has reached the correct position, the forks are inserted and lowered towards the pallet using a balanced force, so that they are in an inserted position above the load carrier and exert a certain downward force on the load carrier. The locking material 4, which may consist of a continuous paper band, is then laid out across the pallet and the first layer of packages is placed in the compartments formed by opposite forks .

The load carrier is then lowered a level, during which operation the load directing means remain in their active position on the pallet, thus providing full sup- port also to the outermost packages.

The apparatus may further comprise support means, such as girders, adapted to support the long sides of the outermost loaded objects. However, normally it is not possible to use such support means during the lowering operation. The new load directing means however provide full package support also during lowering as opposed to prior art, in which it is only the tension of the locking material that retains the outermost packages .

After the lowering operation, the forks are locked in their vertical position and axially retracted from the pallet and thus returned to the inactive waiting posi- tion. To load any additional layers they can then be raised again to their upper position and positioned above the pallet . The load directing means are then preferably displaced laterally a distance corresponding to approximately half the diameter of the cylindrical objects, fol- lowing which the unit is lowered using a balanced force so as to touch down on the most recently loaded layer. The above process is then repeated until the programmed number of layers has been arranged on the pallet. Fig. 1 illustrates a load carrier during loading of the first layer, while Fig. 2 illustrates loading of a subsequent layer.

Thus, the loading method as described above can be summarised as the following sequence of steps : 1. A load carrier is arranged in an upper position. 2. Load directing means are moved into a position above the load carrier and lowered towards the same.

3. One layer of objects is loaded.

4. The load carrier is lowered a layer level together with the load directing means, which during this opera- tion are retained in their active load directing position.

5. The load directing means are locked vertically and retracted axially.

6. The load directing means are raised to their upper position.

7. The load directing means are moved into a position above the pallet and the most recently loaded layer. 8. The load directing means are lowered using a balanced force towards the most recently loaded layer.

9. The process is repeated from step 3 until the desired number of layers has been loaded. The invention has been described above with the aid of embodiments. However, it will be appreciated by the person skilled in the art that many variants are possible. It is possible, for example, to use the load directing means together with other types of loading equip- ment using, for instance, other loading means than pickup arms. It is also possible to use different types of locking material, and to lay it out in different patterns, such as a single loop, double loops, or to use different types of locking layers. Furthermore, the load directing means may be designed in other ways than those described above. For example, the number of arms on the fork unit may be different, so that there is not one arm between each loaded object but only between every second or third object or the like. Moreover, it is possible to use other means than arms, such as a corrugated plate, a waved girder that is perpendicular to the axial direction of the loaded objects, or the like. Other types of profiled means may also be used and inserted among the loaded objects to obtain essentially the same retaining and load directing effect. In addition, the load directing means may be operated using various types of operating means, such as electric motors, hydraulic or pneumatic driving means or the like. It is further possible to use only one load directing means, to use two as described in the above embodiment , or to use more than two .

These and other close variants must be considered to be covered by the scope of the invention as defined by the appended claims .

Claims

1. An apparatus for loading elongated, essentially cylindrical objects onto a load carrier, comprising means for arranging the objects side by side in layers on the load carrier, and a plurality of such layers on top of each other, and means for laying out a locking material in a loop between the layers, c h a r a c t e r i s e d in that it further comprises at least one load directing means, which during loading is displaceable towards and away from the loaded objects in a direction which is essentially parallel to the axial direction of said objects.

2. An apparatus according to claim 1, wherein the load directing means is displaceable between a load directing position and an inactive position, the load directing means being positioned, in the load directing position, above the loaded objects.

3. An apparatus according to claim 2, wherein the load directing means, in the load directing position, is adapted to exert a force in the direction of the load carrier.

4. An apparatus according to any one of the preceding claims, wherein the load directing means comprises a plurality of arms oriented towards the loaded objects.

5. An apparatus according to claim 4, wherein the load directing means comprises at least the same number of arms as the number of objects to be loaded in each layer, the objects being arranged during loading between pairs of adjoining arms.

6. An apparatus according to any one of the preceding claims, wherein one load directing means is arranged on each side of the loaded objects, the load directing means being moved respectively towards and away from each other during use.

7. An apparatus according to any one of the preceding claims, further comprising a vertically adjustable lifting platform adapted to support the load carrier during loading, the top layer on the load carrier preferably being kept at essentially the same level at all times .

8. An apparatus according to any one of the preceding claims, wherein the length of the objects to be loaded is considerably greater than their diameter.

9. An apparatus according to any one of the preceding claims, wherein the diameter of the objects to be loaded is considerably smaller than the length or width of the load carrier.

10. A method of loading cylindrical objects onto a load carrier, comprising the steps of arranging elongated, essentially cylindrical objects side by side in layers on the load carrier, and a plurality of such layers on top of each other, and laying out a locking material in a loop between the layers, c hara c t e r i s e d in that it further comprises the step of moving a load directing means, prior to loading a new layer, into a position such that the new layer is at least partly loaded onto said load directing means, and retracting the load directing means after loading said layer.

11. A method according to claim 10, wherein the load directing means is inserted in a direction which is essentially parallel to the axial direction of the objects.

12. A method according to claim 10 or 11, wherein the load directing means comprises a plurality of arms oriented towards the loaded objects, said objects being arranged during loading between pairs of adjoining arms.

13. An apparatus for directing the load in connec- tion with automated loading of elongated, essentially cylindrical objects onto a load carrier, c h a r a c - t e r i s e d in that it comprises at least one load directing means, which during loading is displaceable towards and away from the loaded objects in a direction which is essentially parallel to the axial direction of said objects.