Hegardt, Johan (V Torggatan 5 Teckomatorp, S-260 20, SE)
Kullegård, Bengt (Västervång 4 Södra Sandby, S-247 34, SE)
Nordell, Joakim (Illervägen 13 Löddeköpinge, S-246 50, SE)
Aldin, Anders (Snöbärsgatan 2 Svedala, S-233 35, SE)
Hegardt, Johan (V Torggatan 5 Teckomatorp, S-260 20, SE)
Kullegård, Bengt (Västervång 4 Södra Sandby, S-247 34, SE)
Nordell, Joakim (Illervägen 13 Löddeköpinge, S-246 50, SE)
| 1. | An apparatus for receiving a layer unit (14) on pallet unit (1) or alternatively on a pallet (2), characterised in that the apparatus includes a centring frame (15) over which there is placed a first indicator (17,18) operative to determine the upper surface (24) of the pallet unit (1) or alternatively the pallet (2), and a second indicator (19,20) placed at welldefined height (H) above the upper surface (24). |
| 2. | The apparatus as claimed in Claim 1, characterised in that the centring frame (15) is provided on each side with pressure plates (23) disposed to compress the packaging containers (3) previously received on the pallet unit (1). |
| 3. | The apparatus as claimed in Claim 2, characterised in that the centring frame (15) is selfadjusting, since the pressure plates (23) are disposed to compress the packaging containers until a certain resistance is reached. |
| 4. | The apparatus as claimed in Claim 1, characterised in that the second indicator (19,20) is placed in a forkshaped bracket (21). |
| 5. | A method of receiving a layer unit (14) on a pallet unit (1), characterised in that the method comprises the steps that a centring frame (15) moves upwards until a first indicator (17,18) placed just above the upper edge of the centring frame (15) detects the upper surface (24) of the pallet (2), or alternatively the upper surface (24) of the pallet unit (1), and that a second indicator (19,20) placed at a welldefined height (H) above the upper surface (24) emits a signal to an apparatus which lowers a new layer unit (14) towards the upper surface (24) of the pallet (2) and, when signal is given, retards the speed of the apparatus. |
BACKGROUND ART For selling foods to consumers, large food retail outlets today often elect to convey the goods into the retail outlet direct on the pallet on which the goods were supplied to the retailer. A large quantity of goods is sold in this manner, regularly or in connection with special sales campaigns, including liquid foods such as juice, fruit drinks, water and the like. Such foods are often packed in single-use disposable packages of the type which, for example, may have a parallelepipedic configuration.
In order to achieve the best sales outcome results, the aim is to have a stable pallet unit at the same time as the intention is to expose as much as possible of the product. In order to obtain a stable unit, the individual packages have most generally been packed in corrugated cardboard trays, possibly with a wrapping of corrugated cardboard. In order to achieve a favourable exposure of the packages, any possible wrapping must be torn away, which is a time-consuming operation. Also in recycling in retail outlets, both the tray and the wrapping must be taken care of. Nor are the costs for such corrugated cardboard components negligible. Attempts have also been made to place the packages direct in low corrugated cardboard boxes, corresponding to the surface of the pallet, or use has also been made of interlays which have been friction treated between each layer on the pallet. However, both of these methods result in extremely unstable pallet units and the risk that the packages fall off and be damaged is very great.
Loading a pallet with packages in a pallet loader entails that the packages, in a first separate machine, have been marshalled together to units, placed in trays and possibly provided with a wrapping. These units
are then placed one-by-one on a pallet in a further machine. However, manual packing of pallets still occurs to a large extent.
A major problem in all pallet loading is that the position of the surface on which a unit in some form is to be placed must be known.
Normally, this position is fixed or manually programmable, i. e. there must be a large number of manual settings for pallets of varying and unknown dimensions. If the height of the unit is unknown and varies, the position of reference surface must be detected on each placing and be recycled to the apparatus which is placing the unit. By disposing position indicators on the apparatus which places the unit, there is very little time to determine the reference surface, which may injuriously affect the exactness with which the apparatus places the unit.
OBJECTS OF THE INVENTION One object of the present invention is to realise an apparatus which, in a simple and reliable manner, can detect the surface on which the new layer in a pallet-loaded unit is to be placed and which ensures that the placing is stable and exact.
A further object of the present invention is that the detection of the reference surface on which the unit is to be placed is separated from the apparatus which is to deposit the unit, which implies that a considerably longer period of time is made available dliring which the reference surface can be defined.
SOLUTION These and other objects have been attained according to the present invention in that the apparatus of the type disclosed by way of introduction includes a centring frame over which a first indicator is placed, operative to determine the upper surface of the pallet unit or alternatively the pallet, and a second indicator placed at a well-defined height H above the upper surface.
Preferred embodiments of the present invention have further been given the characterising features as set forth in the appended subclaims.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS One preferred embodiment of the present invention will now be described in greater detail hereinbelow, with particular reference to the accompanying Drawings. In the accompanying Drawings: Fig. 1 shows a pallet-loaded unit of the type which can be loaded employing the method and the apparatus according to the present invention; Fig. 2 shows an interlay sheet, unfolded; Fig. 3 shows an interlay sheet, folded; and Fig. 4 shows an apparatus according to the present invention; The Drawings show only those details essential to an understanding of the present invention, and the placing of the apparatus in a complete pallet loader, which is well-known to a person skilled in the art, has been omitted.
DESCRIPTION OF PREFERRED EMBODIMENT The present invention relates to a method and an apparatus for receiving a layer unit on a pallet-loaded unit 1. The pallet-loaded unit 1 may have the appearance as shown in Fig. 1. The pallet-loaded unit 1 comprises a load carrier or a pallet 2, and a number of individual objects 3 in a number of layers 4, and also foldable interlay sheets 5 placed between each layer 4 of individual objects 3. The objects 3 may, for example, consist of parallelepipedic packaging containers of single-use disposable type, intended for liquid foods. For example, the pallet 2 may consist of a so- called quarter pallet which has a format making it suitable to be handled in the retail trade. The present invention may also be employed for other types of pallets of other formats. Above the pallet 2, a planar interlay sheet 6 is placed with a view to protecting the packaging containers 3.
Between each layer 4 of packaging containers 3, there is disposed an interlay sheet 5. The interlay sheet 5, which is shown in greater detail in Figs. 2 and 3, may be of the type which is sold under the name Tetra Layera"'. The interlay sheet 5, which is shown in the unfolded state in Fig. 2, has a continuous pattern of fold lines 7 and punchings 8. The pattern is placed along each edge of the interlay sheet 5. The interlay
sheet 5 is further provided with obliquely cut-off corner portions 9 in all four corners.
The interlay sheet 5 is folded in that the edges are urged upwards and, in such instance, the edges are formed as a frame 10 around a planar surface 11 (Fig. 3). The edges are folded in the fold lines 7 and then form the frame 10, at 90° to the planar surface 11. The frame 10 extends on both sides of the surface 11. By having an extent of the frame 10 on both sides of the surface 11, there will be obtained, as shown in Fig.
1, an interlay sheet 5 with a frame 10 which has one portion 12 which supports the packaging containers 3 in a lower layer 4', and a portion 13 which supports the packaging containers 3 in an upper layer 4". The packaging containers 3 in the upper layer 4"are placed on the planar surface 11.
The packaging containers 3 are advanced in to the pallet loader on some form of conveyor belt, for example an endless, driven belt or chain of conventional type. The packaging containers 3 are marshalled and grouped into a pre-selected packing pattern with the aid of various pushers. The packaging containers 3 marshalled into a packing pattern are thereafter transferred to an interlay sheet 5,6. The interlay sheet may be of the foldable type 5 or alternatively be planar 6. Alternatively, the packaging containers 3 are grouped direct on the interlay sheet 5,6.
If the interlay sheet 5 is of the foldable type, the sheet 5 is thereafter folded for the formation of the frame 10 in a workstation intended for this purpose. The frame 10 is formed in that a folder frame with blocks shears the edges of the interlay sheet 5 upwards. The frame 10 is held in the folded position by means of support plates which, beneath the sheet 5, are urged against the portion 12 of the frame 10.
Those packaging containers 3 which are now placed on a folded interlay sheet 5 constitute, together with the interlay sheet 5, a layer unit 14. A layer unit 14 may also consist of the grouped packaging containers 3 and a planar interlay sheet 6. Alternatively, the present invention may be employed for a layer unit 14 which consists of a single compact unit which occupies the entire surface on the pallet 2.
The layer unit 14 is ready to be lifted, moved horizontally and be placed on a subjacent layer 4 in the pallet-loaded unit 1, or alternatively
direct on the pallet 2. A gripper head, connected to a linear unit, collects the layer unit 14. The linear unit may, for example be servo controlled, frequency controlled or controlled by means of pneumatics. The gripper head has pressure plates which compress both the packaging containers 3 and the frame 10 which surrounds the packaging containers 3.
The apparatus for receiving the layer unit 14 is shown in Fig. 4.
The apparatus comprises a centring frame 15 which is movable in the vertical direction, along a linear unit 16. The linear unit may, for example, be servo controlled, frequency controlled or controlled by means of pneumatics. Where the apparatus is placed, there is a pallet 2 in the loading position with or without previously placed layer units 14 on the pallet 2. Just above the upper edge of the centring frame 15, there is disposed a first indicator or sensor, e. g. a pair of photocells 17,18 or inductive transducers. These first indicators 17,18 are disposed to detect the upper surface 24 of the pallet-loaded unit 1. The placing of the indicators 17,18 is adjustable and is adapted to that type or size of packaging container 3 which is to be loaded.
The apparatus also includes a second indicator or sensor, in the preferred embodiment inductive transducers 19,20. The second indicator is placed at a certain, well-defined height H above the detected surface 24.
The inductive transducers 19,20 are, in the preferred embodiment, placed on each side in a fork-shaped bracket 21. The gripper head which is to deposit the unit 14 has a flag 22 which is disposed to pass the opening in the fork-shaped bracket 21. Two transducers 19,20 are employed in the preferred embodiment in order to increase the reliability of the detection.
The centring frame 15 is also provided with pressure plates 23, one on each side inside the frame 15. The pressure plates 23 are controlled, for example, each by a piston and cylinder assembly. In that the placing of the first indicator 17,18 is adjustable in relation to the upper edge of the centring frame 15, it will be determined where the pressure plates 23 will abut against the packaging containers 3.
The apparatus as shown in Fig. 4 is ready to receive a layer unit 14. The layer unit 14 has been collected, transported horizontally and is now finally to be placed on the pallet 2 or alternatively on the pallet- loaded unit 1. The layer unit 14 may consist, as described above, of a
number of packaging containers 3 placed on a foldable interlay sheet 5.
The layer unit 14 is collected and relocated by the gripper head (not shown).
During the time when the gripper head is collecting a layer unit, the centring frame 15 moves upwards along its linear unit 16 from the position it occupied when an earlier layer unit 14 was placed, or alternatively from the bottom position if a new pallet 2 is to be loaded. The Drawing shows the pallet 2 with two layer units 14 in place. It is thus on the surface 24 which constitutes the upper surface 24 of the already placed upper layer unit 14 on which a new layer unit 14 is to be placed. When the first indicator 17,18 detects the upper surface 24, the centring frame stops its upward movement. The photocells 17,18 which constitute a transmitter and a receiver, register a signal.
In order to facilitate deposition of a new layer unit 14, the pressure plates 23 are now activated in the centring frame 15 and are pressed down towards the packaging containers 3 in the placed layer unit 14. The centring frame 15 is self-adjusting in relation to the packing pattern of the packaging containers 3 which is employed, in that the pressure plates 23 are pressed against the packaging containers 3 until a certain resistance is reached. By pre-determining this resistance, the centring frame can be self-adjusting to all packing patterns which cover the greater part of the surface of the pallet type being employed.
The gripper head, which arrives with a layer unit 14 which is to be placed, compresses this together with the interlay sheet 5 and, in that the interlay sheet 5 is compressed against the packaging containers 3, the frame 10 on the interlay sheet 5 will have a slightly funnel-shaped appearance. The funnel form and the packaging containers 3 compressed by the centring frame 15 entail that the deposition of the new layer unit will be easy and exact.
When the flag 22 which is placed on the gripper head passes the opening in the fork-shaped bracket 21, the signal between the inductive transducers 19,20 is broken. The downward movement of the gripper head is retarded and the gripper head thereafter moves a certain, well- defined distance H. Thereafter, the gripper head stops and the new layer unit can be placed very exactly and reliably on the surface 24. The gripper
head releases its grip on the layer unit 14 and thereafter returns to collect a new layer unit.
The position of the centring frame 15 is registered by a digital pulse emitter 25 placed on the linear unit 16 of the centring frame 15. By subtracting, in the control system of the pallet loader, the previous position of the centring frame 15 from the new position, the height of the layer unit 14 can be determined. The result can be employed for verifying, or alternatively determining, the number of layer units 14 which are selected or alternatively can be selected and placed above one another in a pallet-loaded unit 1, depending upon the size of the packaging containers 3. The pallet-loaded unit 1 may not exceed a certain maximum height, since it must be freely able to be moved out from the pallet loader after it has been ready-loaded.
Once the new layer unit 14 has been placed on the pallet unit 1, the centring frame 15 seeks for a new surface 24 and the apparatus is ready to receive an additional layer unit 14. When the desired number of layers 4 is placed on the pallet 2, the centring frame moves upwards to an end position above the pallet-loaded unit 1. The ready-loaded pallet unit 1 is moved away from the loading position and a new pallet 2 is fed in for loading.
As will have been apparent from the foregoing description, the present invention realises an apparatus and a method where, by separate detection of an upper surface from the deposition of a layer unit, an apparatus will be obtained which affords time gains in operating cycle times. The time gains may be employed for realising a more reliable and exact placing of the layer unit.