The present invention refers to a high-speed robotized palletizing island and to a relative palletizing process.

In robotized palletizing islands essentially the following areas can be identified, the function of which is specific and dedicated to precise purposes:

- layer-forming module, which has the function of forming the layer that must be palletized and that is made of bundles, cartons, etc.;

- robot palletizing unit, in which the depositing of the layers onto the pallet is carried out;

- inter-layer sheets depositing unit, in which the inter-layer sheet is deposited onto the pallet, between the layers of the pallet and on the upper part of the pallet formed;

- pallet treatment module, in which the pallets are selected, the integrity thereof is checked and the suitable pallets pass to palletization, whereas the discarded ones are stacked outside the island;

- pallet wrapping and transfer module, in which the complete pallets of products are wrapped and transferred to the pick-up area.

The speed of the entire robotized palletizing island is limited by the slowest speed of the single modules or units described above.

A limit to the speed essentially consists of the palletizing unit, the cycle of which, namely the time for carrying out a work cycle for the formation of a pallet, is dictated by different times, such as: - gripping time;

- layer transfer time;

- approach time to the pallet;

- gripper opening time on the pallet;

- gripper withdrawal time from the pallet under formation;

- gripping transfer time towards the layer formation area .

In the palletizing unit it is also necessary to take into account a time needed to deposit the inter-layer sheets between the layers, and a time to deposit an inter-layer sheet on top of the pallet, which in general for low and medium-speed islands are masked by the main robot times.

In the palletizing unit, a time necessary for evacuating the finished pallet and a time for the entry of the next empty pallet are also recorded. These times are also masked by the main robot times in low and medium-speed islands.

The purpose of the present invention is to make a high-speed robotized palletizing island and a relative palletizing process, which allow the speed limits of the palletizing unit to be overcome.

Another purpose of the present invention is to make a high-speed robotized palletizing island and a relative palletizing process capable of also improving the efficiency of the other modules or units of the island, and in particular of the inter-layer sheets depositing unit.

Another purpose of the present invention is to make a high-speed robotized palletizing island and a relative palletizing process that is particularly simple and functional.

These purposes according to the present invention are accomplished by making a high-speed robotized palletizing island and a relative palletizing process as outlined in the independent claims.

Further characteristics are provided for in the dependent claims.

The characteristics and advantages of a high-speed robotized palletizing island and of a relative process according to the present invention will become clearer from the following description, given as an example and not for limiting purposes, referring to the attached schematic drawings, in which:

figure 1 is a plan view of a first embodiment of a robotized palletizing island, according to the invention;

figure 2 is an enlarged detail of figure 1 ;

figure 3 is a plan view of an enlarged detail of a second embodiment of a robotized palletizing island, according to the invention;

figures 4-6 schematically show the sequence of the steps of the starting transient of the palletizing process according to the invention;

figures 7 and 8 schematically show the sequence of steps of the palletizing process according to the invention .

With reference to the figures, a high-speed robotized palletizing island is shown, wholly indicated with 100.

The palletizing island 100 comprises a layer- forming module 10, a palletizing unit 20, an inter- layer sheets 30 depositing unit, a pallet treatment module 40 and a wrapping unit 50.

Layers 11 of products that must be palletized are formed in the layer-forming module 10. According to known ways, the layer formation module 10 comprises bundle handling robots 12 for handling the bundles on a succession of conveyor belts, or mats 13.

Two different pick-up stations 21A and 21B of the layer 11 formed by a part of the two robots for picking up the layer 22A and 22B, for example of the gripper type, are arranged in series with respect to each other on a single exit conveyor 14 of the layer-forming module 10. Each of the layer pick-up robots 22A and 22B, according to normal operating conditions, picks up a layer 11 in turn, respectively from the pick-up station 21A and 21B dedicated thereto and deposits it onto an empty pallet 41 and/or one pallet under formation 42 respectively in one of the two forming areas 23A and 23B of the palletizing unit 20 dedicated thereto .

According to a preferred embodiment of the invention, at least one first accumulation area during formation 23' is arranged between the two forming areas of the pallet 23A and 23B. Preferably, a first 23' and a second 23' ' accumulation areas during formation are provided.

The forming areas 23A and 23B and the accumulation areas during formation 23' and 23' ' are arranged in series with respect to each other along a feeding direction of the pallet under formation, shown with the arrow F in the figures.

The inter-layer sheets depositing unit 30 comprises two robots for inter-layer sheets 33A and 33B, which each picks up an inter-layer sheet 31 from a respective pallet of inter-layer sheets 32A and 32B and deposit it in the palletizing unit 20, in particular onto the empty pallet 41 and/or onto the pallet under formation 42 and/or onto the finished pallet 43, in the respective forming area 23A and 23B. In the figures, the robots for inter-layer sheets 33A and 33B are shown as an example both in the pick-up position of the inter-layer sheet 31 on the pallet of inter-layer sheets 32A and 32B and in the depositing position of the inter-layer sheet 31 in the corresponding forming area 23A and 23B.

In the pallet treatment module 40, the empty pallets 41 are selected, in order to transfer the suitable ones towards the palletizing unit 20 and the discarded ones towards a store 44.

In the pallet wrapping and transfer module 50, the complete pallets 43 are wrapped and transferred in a pick-up area 51.

A second embodiment of the palletizing island 100' comprises the same elements described for the first embodiment 100 except for the inter-layer sheets depositing unit 30', which comprises, in addition to what already described, first means 34 for transferring the emptied pallets of inter-layer sheets between the work areas of the robots for inter-layer sheets 33A and 33B and the accumulation areas during formation 23' and 23'' of the palletizing unit 20, as well as further means 35 for transferring the new and/or empty pallets of inter-layer sheets 32A and 32B between the work areas of the robots for inter-layer sheets 33A and 33B and waiting areas 36A and 36B. The further transfer means 35 preferably comprise two conveyors arranged on two parallel planes laid one upon the other, not shown. In this case, the waiting areas 36A and 36B can be equipped with a lifting platform, not shown.

The palletizing process in the island 100' , according to a first operating mode, provides that when the pallets of the inter-layer sheets 32A and 32B are emptied, instead of being replaced manually, they are unloaded in the accumulation areas during formation 23' and 23' ' , previously left free by the pallets under formation 42, are stored and discarded along the feeding direction of the pallet under formation F in a discard position 123 arranged downstream of the palletizing unit 20, namely downstream of the second forming area 23B. The new pallets of inter-layer sheets 32A and 32B will be automatically transferred from the waiting areas 36A and 36B to the work areas of the robots for inter-layer sheets 33A and 33B through the further transfer means 35. In this case, the normal palletizing cycle will have to follow a modified scheme that will be followed by a specific transient in order to go back to normal operating conditions.

Contrarily, a second operating mode provides that when the pallets of inter-layer sheets 32A and 32B are emptied, the same are transferred to the waiting areas 36A and 36B through the conveyor arranged on the lower plane of the transfer means 35. At the same time, the conveyor arranged on the upper plane of the transfer means 35 transfers the new pallets of inter-layer sheets 32A and 32B from the waiting areas 36A and 36B to the work areas of the robots for inter-layer sheets 33A and 33B. According to the invention, the production capacity is in particular increased by providing for two layer pick-up robots 22A and 22B in the palletizing unit 20 and two corresponding robots for inter-layer sheets 33A and 33B in the inter-layer sheets depositing unit 30, as well as by providing that these robots operate on the two distinct pallet forming areas 23A and 23B, without ever crossing each other.

In fact, if the pallet forming area were not splitted, there would be a risk of over-occupation of area on the pallet due to the time to approach the pallet, to open the gripper on the pallet, to withdraw the gripper from the pallet under formation, to lay inter-layer sheet onto the pallet and to transfer the pallet.

The accumulation areas during formation 23' and 23' ' , if present, also contribute to the increase in productivity. In fact, in particular the second accumulation area during formation 23' ' , immediately upstream of the second forming area 23B allows half a pallet under formation 42 to be transferred in the second forming area 23B in the shortest time possible after the unloading of the finished pallet 43.

The first accumulation area during formation 23', not directly involved in the palletization step through the robots, is used in collaboration with the other accumulation area during formation 23' ' for automatically unloading the empty pallets for inter- layer sheets 32A and 32B in reduced times in the second embodiment of the island 100' . Differently, in the island 100 according to the first embodiment the first accumulation area during formation 23' under normal operating conditions constitutes a transit area and can possibly be used as accumulation for half a pallet under formation 42, in the case of temporary stopping or slowing down of the second layer pick-up robot 22B or of unloading from the palletizing unit in the feeding direction F.

The high-speed palletizing process in the robotized palletizing island is carried out after a starting transient, schematically shown in figures 4-6.

Figures 7 and 8, on the other hand, schematically show a work cycle of the palletizing process under normal operating conditions.

For the sake of ease of representation, in the figures relative to the schematization of the process, reference numeral 11A indicates the layers deposited by the first layer pick-up robot 22A and reference numeral 11B indicates the layers deposited by the second layer pick-up robot 22B. Similarly, reference numeral 31A indicates the inter-layer sheets deposited by the first robot for inter-layer sheets 33A and reference numeral 31B indicates inter-layer sheets deposited by the second robot for inter-layer sheets 33B.

The figures show the particular case in which the finished pallet 43 comprises a total of four layers 11, two of which 11A are deposited by the first layer pick ^¬ up robot 22A and two of which 11B are deposited by the second layer pick-up robot 22B.

In the starting transient of the high-speed palletizing process, in the robotized palletizing island, two half pallets 42 are formed, which are provided with an inter-layer sheet 31 on the last layer 11. Such two half pallets 42 are for example formed, one in succession to the other, on an empty pallet 41 in the sole first forming area 23A through the alternate depositing of inter-layer sheets 31 and layers 11A carried out by the first layer pick-up robot 22A and by the first robot for inter-layer sheets 33A and thus respectively directed in the second accumulation area during formation 23' ' and in the second forming area 23B.

The palletizing cycle under normal operating conditions starts with two half pallets 42, provided with an inter-layer sheet 31A at their top positioned in the second forming area 23B and in the second accumulation area during formation 23' ' and provides depositing in succession a layer 11B onto a half pallet 42 covered by the inter-layer sheet 31A in the second forming area 23B and a layer 11A on an empty pallet 41 covered by the inter-layer sheet 31A in the first forming area 23A; it then proceeds with depositing in succession inter-layer sheets 31 and layers 11 in the second and in the first forming areas 23B and 23A until a finished pallet 43 covered by an inter-layer sheet 31B in the second forming area 23B and half a pallet 42 covered by an inter-layer sheet 31A in the first forming area 23A are respectively obtained (figure 7) .

The finished pallet 43 is unloaded from the palletizing unit 20 in the feeding direction F and transferred to the pallet wrapping and transfer module 50; the half pallet 42 that is waiting in the second accumulation area during formation 23' ' is transferred in the second forming area 23B and the half pallet formed in the first forming area 23A goes into the second accumulation area during formation 23' ' , passing through the first accumulation area during formation 23' . Then a new palletizing cycle starts according to what is described and shown.

According to the invention, in order to increase productivity, every time the operations end in a formation area 23A or 23B or in an accumulation area during formation 23' or 23' ' , it the same is cleared in the shortest delay in order to be immediately used for the following palletization step.

Moreover, the simultaneous use of two different forming areas 23A and 23B, in which only half a pallet is formed allows making the layer pick-up robot of one formation area and the robot for inter-layer sheets of the other formation area work simultaneously.

According to a simplified solution, not shown, in the absence of the accumulation areas during formation 23' and 23' ' , in the starting transient, half a pallet 42 is formed in the first forming area 23A and directly transferred in the second forming area 23B in order to start the palletizing cycle.

The fact that in each of the forming areas only half a pallet is formed assures numerous advantages deriving from the fact that each of the robots for inter-layer sheets will never have to deposit two inter-layer sheets onto the pallet under formation in sequence but just one. Moreover, the pallet transfer time will never be of two pallets but always of only one .

A further advantage is given by the presence of two pick-up stations downstream of the layer formation area, instead of only one. Besides making the operation of the two robots for picking up the layer safer, which do not risk to hinder one another, this solution gives working continuity to the layer-forming module in the case in which the times of the operations in the palletizing unit were greater than the layer formation time in the first pick up station. In this case, the layer composed and formed in the first position would be rested in the second position and then picked up afterwards .

The high-speed robotized palletizing island thus conceived can undergo numerous modifications and variants, all of which are covered by the invention; moreover, all of the details can be replaced by technically equivalent elements. In practice, the materials used, as well as the sizes, can be whatever according to the technical needs.