WO1983003808A1

WO1983003808A1 - Palletless materials handling

Info

Publication number: WO1983003808A1
Application number: PCT/SE1983/000179
Authority: WO
Inventors: Anders Ingvar Persson
Original assignee: Industriconsult I Ängelholm Ab
Priority date: 1982-05-05
Filing date: 1983-05-05
Publication date: 1983-11-10
Also published as: SE8202797L

Abstract

In a method for producing a stack of goods (10) consisting of load units (11), the lowermost layer (12) of load units is made narrower than the other layers (13) of load units so as to form channels for the prongs of a lifting fork or the like. The stack of goods is thereafter displaced on a conveyor belt (3, 4) in order to be wrapped in a plastic film (14, 17) which passes through the conveyor belt as a vertical wall of plastic film. The lowermost layer (12) of load units is placed on a central run (5) of the conveyor belt (3), and vertically movable runs (6) of the conveyor belt which are disposed on either side of the central run are adjusted to a level with the upper face of the lowermost layer of load units; then, the next layer (13) of load units which is wider than the lowermost layer is placed on said side runs and said upper face. A device for producing a stack of goods (10) which consists of load units (11) and whose lowermost layer (12) of load units is narrower than the other layers (13) of load units so as to form channels for the prongs of a lifting fork or the like comprises a conveyor belt (3, 4) for moving the stack of goods towards a vertical wall of plastic film (14, 17) passing through the conveyor belt for wrapping the stack of goods in the plastic film. The conveyor belt consists of a central run (5) on which the lowermost layer (12) of the stack of goods is placed, and of vertically movable side runs (6) disposed on either side of the central run. A means is provided for adjusting the side run to a level with the upper face of the lowermost layer.

Description

PALLETLESS MATERIALS HANDLING

The present invention relates to palletless mate¬ rials handling and more particularly to a method of pro¬ ducing a stack of goods which consists of load units and whose lowermost layer of load units is made narrower than the other layers of load units so as to form chan¬ nels for the prongs of a lifting fork or the like, said stack of goods being displaced on a conveyor belt in order to be wrapped in a plastic film which passes through the conveyor belt as a vertical wall of plastic film. The invention also relates to a device for carrying out this method.

The trend of today's technique goes towards building up stacks of goods consisting of load units, without the assistance of pallets. This technique is referred to as "palletless" materials handling. The need to lift the stack of goods by means of a lifting fork or the like necessitates the provision of guide channels for the prongs of the lifting fork in the lowermost layer of the stack of goods. The instability occurring in the stack of goods as load units are excluded from the lowermost layer is overcome by wrapping a shrinkable plastic film around the stack and thereafter placing the stack in a shrink tunnel, such that the plastic is tightened around the stack so as to support the load units. This will give a stack of goods which holds together and can be raised by means of a lifting fork.

The application of shrinkable plastic film around the stack of goods has hitherto been effected in dif¬ ferent ways which either require expensive machinery or give unsatisfactory results.

Swedish patent application 7703173-0 discloses a method of applying a shrinkable plastic film around a stack of goods, in which the stack is built up with the guide channels facing upwards. A plastic hood is there- after passed over the stack of goods, and the stack equipped with the plastic hood is then placed in a shrink tunnel. The stack of goods is thereafter turned so that the guide channels are facing downwards, before a second plastic hood is passed over the stack from the opposite direction, whereupon the stack is again placed in a shrink tunnel. This technique gives a satisfactory result but requires a very expensive equipment, inter alia a device for turning the stack of goods, and two shrink tunnels.

SE 385287 discloses a method for wrapping plastic around a stack of goods which is displaceable on a con¬ veyor and whose guide channels are facing downwards. The conveyor is intersected at two locations by a wall of plastic film which is fed from supply rolls. After completed wrapping, the plastic films are welded to¬ gether. This technique is simple and, in relation to the first-mentioned publication, requires a less expensive equipment, but it will give unsatisfactory results be- cause the stack is not supported before the wrapping operation and because the plastic film is not properly conformed to the guide channels.

The object of the present invention, therefore, is to provide a method and a device for palletless mate- rials handling of the type mentioned by way of introduc¬ tion, which obviates the drawbacks of the prior art methods and devices.

According to the invention, this object is achieved by the provision of a method and a device, the features of which appear from the characterising clauses of the accompanying claims 1 and 3, respectively.

The present invention is advantageous in so far as it makes it possible, by means of a relatively simple and inexpensive equipment, to build up a stack of goods with guide channels for the prongs of a lifting fork and apply the plastic film around the stack of goods which is supported during the entire operation in a satisfactory manner, the plastic film being closely con¬ formed to the walls of the guide channels in the bottom of the stack of goods.

The invention will be described in greater detail hereinbelow by a schematically illustrated embodiment and with reference to the accompanying drawings.

Figs. 1-5 show different steps in the manufacture of a stack of goods wrapped in shrink film.

Fig. 6 is a front view of the stack of goods in the step shown in Fig. 3.

In Fig. 1, there is shown a loading device 1 which is supplied with load units 11 and in which the units can be arranged in layers of load units on a vertically and horizontally movable loading surface 2. When a layer of load units with the desired shape and number of units has been placed on the loading surface 2, the layer of load units is transferred onto a conveyor belt 3 by means of a stripper (not shown) . This is done by first moving the loading surface 2 horizontally to a position above the conveyor belt and then retracting it, whereby the stripper will force the layer of load units off the load¬ ing surface.

The conveyor belt 3 which is an endless belt con¬ sists of a fixed central run 5 and raisable and lowerable side runs of which only one 6 is shown in the drawings. When the lowermost layer 12 is transferred from the load¬ ing surface 2 onto the conveyor belt 3, the side runs 6 are on a level with the central run 5. The lowermost or first layer 12 should be narrower than the other layers to provide guide channels for the prongs of a lifting fork, and the width of the layer should substan¬ tially correspond to the width of the central run 5 of the conveyor belt. When the lowermost layer has been applied, the side runs 6 are raised to a level with the upper face of the lowermost layer. The two side runs and the upper face of the lowermost layer will form a supporting surface for a second load unit layer 13 of greater width which is transferred from the loading sur¬ face in the manner described above. The remaining layers of load units will then be applied until a finished stack of goods 10 has been formed. Thanks to the side runs 6 of the conveyor belt 3, which support the lowermost layer but one 13, the stack is stable and the guide chan¬ nels produced extend in the direction of movement of the conveyor belt.

At the end of the conveyor belt 3, there is provided a vertical wall 14 of plastic film which is wider than the stack 10. The plastic film is fed from first and second supply rolls 15 which are disposed above and below, respectively, a second conveyor belt 4 of a design cor¬ responding to that of the conveyor belt 3, i.e. having a fixed central run 7 and raisable and lowerable side runs 8, 9. The side runs 8, 9 are displaced synchronously with the side runs 6 of the first conveyor belt 3 and will thus occupy the same level as the side runs 6. Further, the conveyor belts 3 and 4 are run in synchro- nism as regards both the relation of the side runs to the central run and the relation,of the conveyor belts 3 and 4 to one another. The vertical wall of plastic film 14 is obtained in that the plastic film is guided over pulleys 16 at the upper supply roll 15 and over one end of the second conveyor belt 4.

A reinforcing film 17 of plastic is provided bet¬ ween the conveyor belts 3 and 4 substantially parallel to the wall 14 of plastic film. The reinforcing film 17 is thicker than the wall of plastic film 14, extends to a position slightly above the side runs 6 of the con¬ veyor belt 3 and the side runs 8 and 9 of the conveyor belt 4, and is of a width which corresponds at least to the length of the contour of the underside of the stack of goods, i.e. it should be possible to conform the reinforcing film to the shape of the guide channels and at the same time cover the entire underside of the stack of goods 10. The reinforcing film 17 is fed from a supply roll 18 disposed underneath the first conveyor belt 3 and is guided by means of pulleys 19.

The finished stack of goods 10 is moved on the con¬ veyor belt to engage the wall of plastic film 14 and the reinforcing film 17. When the front of the stack has encountered the films, these will be gradually un¬ rolled from their supply rolls, as shown in Fig. 2, and the films are conformed to the underside of the stack of goods, as appears especially from Fig. 6. Fig. 3 shows the stack of goods 10 when entirely transferred from the first to the second conveyor belt. A cutting and welding device wraps the plastic film 14 around the entire stack of goods 10 and severs the plas¬ tic film wrapped around the stack from the stretches of plastic film which have been unrolled from the supply rolls, these stretches being now welded together to form a new wail of plastic film. However, since this is a well-known technique falling outside the scope of the invention, no detailed description of this cutting and welding device 20 will be made here. It should be pointed out that the reinforcing film 17 has previously been cut off by means of a cutting device (not shown) .

The stack of goods is now surrounded by plastic film on four sides, skirts or flaps of plastic film 25 and 26 depending from the side runs 8 and 9, respective¬ ly, of the conveyor belt 7, as shown in Fig. 6.

The next step consists in applying a hood of plas¬ tic film 21 on the stack, as shown in Fig. 4. In con¬ nection herewith, the flaps of plastic film 25 and 26 mu t be folded up against the stack 10. This is done by a lifting device 22 which is schematically shown in Fig. 4 and which may be arranged vertically movable at the side of the side runs 8 and 9 of the conveyor belt 7. In Fig. 4, there is shown only one such lifting device 22. Optionally, the raised plastic film flaps 25 and 26 may be temporarily fixed to parts of plastic film on the sides of the stack of goods. When the hood of

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OMPI plastic film 21 has been passed over the stack of goods 10, the entire stack will thus be wrapped in plastic film.

Preferably, use is made of shrinkable plastic film in these contexts, and so the wrapped stack of goods is then passed into a shrink tunnel 24 by means of a conveyor belt 23 of a design corresponding to that of the other conveyor belts.

Also, it is possible to replace the shrink film with a stretch film which, instead of applying a hood of plastic film, is wound around the stack of goods, whereby the equipment will become less expensive by the exclusion of the shrink tunnel.

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Claims

1. A method of producing a stack of goods (10) which consists of load units (11) and whose lowermost layer (12) of load units is made narrower than the other layers (13) of load units so as to form channels for the prongs of a lifting fork or the like, said stack of goods being displaced on a horizontal linear conveyor belt (3, 4) in order to be wrapped in a plastic film (14, 17) which passes through the conveyor belt as a vertical wall of plastic film, c h a r a c t e r i s e d in that the lowermost layer (12) of load units is placed on a central run (5) of the conveyor belt (3) in the undriven state thereof? that driven side runs (6) of the conveyor belt which are vertically movable and disposed on either side of the central run are thereafter adjus- ted to a level with the upper face of the lowermost layer of load unitsj that the succeeding layers (13) of load units which are wider than the lowermost layer are suc¬ cessively placed on top of each other on said side runs and said upper face; and that the conveyor belt is star- ted for said displacement of the finished stack of goods (10).

2. Method as claimed in claim 1, c h a r a c t e ¬ r i s e d in that a hood of plastic film (21) is passed over the wrapped stack of goods (10).

3. A device for producing a stack of goods (10) which consists of load units (11) and whose lowermost layer (12) of load units is narrower than the other layers (13) of load units so as to form channels for the prongs of a lifting fork or the like, said device comprising a horizontal linear conveyor belt (3, 4) for displacing the stack of goods towards a vertical wall of plastic film (14, 17) passing through the conveyor belt for wrapping the stack of goods in plastic film, c h a r a c t e r i s e d in that the conveyor belt

-BUREAU _OMP!. consists of a central run (5) on which the lowermost layer (12) of the stack of goods is placed, and of driven side runs (6) which are vertically movable and disposed on either side of the central runj that means are provided for adjusting the side runs to a level with the upper face of the lowermost layer.

4. Device as claimed in claim 3, in which the plastic film is substantially wider than the stack of goods, c h a r a c t e r i s e d by means which are provided at the conveyor belt (4) after the wall of plastic film (14, 17) and adapted to raise the skirts or flaps of plastic film (25, 26) depending from the side runs as a hood of plastic film (21) is being passed over the wrapped stack of goods (10) .

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