Description

A Plant for supplying Products to be palletized and a Process for stacking Mixed Pallets.

Technical Field

The invention relates to a plant for supplying products to be palletized and a process for stacking mixed pallets. By mixed pallets is meant pallets not stacked with a single type of product but those which contain various types of products, often in varying quantities. Background Art

Generally the products to be palletised, when of a same type, are stocked in a determined number in containers positioned on relative support units.

Since stocking warehouses generally comprise a considerable variety of types of products, it is of fundamental importance to optimal productivity levels that the process selected for making up mixed pallets, as well as plant for performing the task, should be of the best possible types.

Today the types of process for making up mixed pallets are subdivided into two main categories, i.e. "man to goods" and "goods to man".

In "man to goods" process, products to be palletised are arranged on relative fixed shelves positioned internally of storage warehouses, among which the operator whose job it is to compose the pallets moves, displacing from a type of product to another and collecting, one by one, the quantity of the relative product required for stacking the pallet.

The number of types of products present in a warehouse considerably influences the size of the warehouse itself and, consequently, the trajectories and the time the operator needs to reach the various products

required to make up the pallet. It is therefore easy to comprehend how man to goods processes render good productivity in cases in which the types of products in the warehouse (and among which the operator must move) are limited in number. Generally the productivity is evaluated in terms of units per hour collected, giving an index on which the number of pallets per hour relies.

In cases in which the variety of the products present in the warehouse is considerable, man-to-goods processes are characterised by a limited hourly productivity, due to the long trajectories (and thus the long movement times) that the operators have to perform in order to reach points where the products to be collected are stored. In these cases it is more advantageous to use the processes known and goods-to-man.

In this type of process, the operator charged with making up the mixed pallet is stationary in a work station, known as a picking station, to which the various types of product are automatically transported.

The operator thus collects the number of units required for making up the pallet for each product arriving at the picking station, after which the remaining products are returned to the corresponding stocking zones inside the warehouse. Generally, goods-to-man processes are performed by using automatic machines which enable collection of the various products from the warehouse, transport thereof up to the picking station and repositioning of the products not collected by the operator newly in the warehouse. In more detail, the automatic machines used comprise a trajectory along which the products to be palletised are moved, externally of which the picking station and the storage warehouse are positioned. The storage warehouses are generally vertically-developing and are provided with stacker cranes, i.e. three-axis robots linearly mobile on

tracks, which enable products positioned at different heights in the warehouse to be picked and positioned on roller planes and/or conveyor belts from which they will be removed to form the relative pallet. Products not picked are then repositioned on the conveyor rollers and newly returned to the storage warehouse by stacker cranes.

Generally some types of products are used for composing the majority of the pallets, while other types are only rarely used.

For this reason, the products present in the warehouse are classified in categories on the basis of frequency of use. There are therefore main products, which might be called class A or super A, which correspond to the most used products, and secondary products, which might be called class B, C etc., which correspond to products used less frequently. With the aim of obtaining maximum productivity from the automatic machines used, known-type plants comprise a first storage zone served by transport shuttles and in which the main products are stored, and a vertically-developing second storage zone served by stacker cranes and containing the secondary products.

The known plants used for making up mixed pallets in the above-described goods-to-man method are not free of drawbacks, among which a main problem is that they do not enable the potential of the plant they are made of to be fully exploited, and are thus characterised by limited productivity. In more detail, especially in cases characterised by a conspicuous variety of products to be collected, both main and secondary, and in which each pallet resulting from the activity has to made up of a few units of each type of main product, the numerous movements the automatic machines are forced to make in order to bring these products to the operator work zone and to return the non-used unit newly into the first storage zone require a considerable amount of time. This use of time penalised productivity, as the

longer the time wasted is, the greater the fractioning of the main products required for making up each pallet.

It follows that the above-described situations, the plant productivity (in terms of number of units per hour) is very low and often such as not to enable rapid amortising of the investment.

The plants in use today, in the particular combination of the equipment they are made up of, and the processes used for making up mixed pallets, have remained the same in recent years, and experts in the sector seem to be constrained to solutions of known type, such as the above-described; this has led to there being established a sort of setting of the ways in the sector and a prejudice relating to the plants and processes which can be used. A further drawback in known plants, in particular for man-to-goods methods, is connected to the spatial dimension. These plants occupy a considerable surface area inside the shed they are positioned in, resulting in a constraint to the flexibility of use of the shed itself.

A foremost aim of the present invention is to obviate the above-described drawbacks in the prior art by provided a plant for supplying products to be palletised and a process for composing mixed pallets which enables high productivity to be obtained even in the presence of a high number of types of products to be picked for making up mixed pallets and a large fractioning of the products in each mixed pallet.

The present invention proposes to provide a plant which enables the advantages of the man-to-goods processes to be blended with the advantages of the goods-to-man processes. An aim of the present invention is to provide a plant for supplying products to be palletised which can be realised using known equipment, thus limiting investment costs, by providing a use methodology which differs from the traditionally-used methods.

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A further aim of the invention is to provide a plant for supplying products to be palletised which enables, apart from improving productivity with respect to known plants, a smaller surface area to be used. A still further aim of the invention is to provide a plant which requires, given a same productivity, a lower economic investment than known plants, as well as less maintenance.

In the ambit of the technical objective, a further aim of the present invention is to provide the set objective and aims with a simple structure which is relatively easy to actuate, reliable and functionally efficient, which is relatively inexpensive and is simple to maintain.

This objective and these aims are all attained by the plant for supplying products to be palletised of a type with one or more main products and one or more secondary products, comprising: at least a first storage zone for the products to be palletised; at least a movement trajectory defining a closed profile; at least a conveyor device for the main and second products which is mobile along the trajectory and is destined to pick and/or drop products to be palletised from the first storage zone; characterised in that the first storage zone comprises at least a stacker crane positioned internally of the trajectory, the conveyor device being destined to move at least part of the products to be palletised from and to the stacker crane.

Disclosure of Invention

Further characteristics and advantages of the present invention will better emerge from the detailed description of a preferred though not exclusive embodiment thereof, illustrated by way of non-limiting example in the accompanying figures of the drawings, in which: figure 1 is a plan view from above of the plant of the invention;

figure 2 is an enlargement of a portion of figure 1; figure 3 is a lateral elevation of a longitudinal section of the conveyor device and a storage bay of the invention; figure 4 is a front elevation of the storage bay of figure 3; figure 5 is a plan view from above of the conveyor device and the storage bay of figure 3; figure 6 is a schematic perspective view of the plant of the invention of figure 1. With particular reference to the figures, a plant for supplying products Pl, P2, P3 is denoted in its entirety by 1.

The products to be palletised P1,P2,P3 are classified as main products Pl, with this term intending that these are the products used most frequently for the composition of the pallets, and as second products P2, P3, with this term intending that these are the products used with less frequency in the composition of the pallets. In turn, the second products can be sub- classified into medium-use products P2 and low-use products P3. The products to be palletised P1,P2,P3 are generally stored on support units, not visible in detail in the figures, such as containers or pallets, each of which enables the movement of a determined number of products of the same type.

Although herein below reference is made only to products to be palletised, main and secondary, these terms are to be taken to mean support units on or in which the products are positioned. The plant 1 comprises at least a first storage zone 2 of at least a part of the products to be palletised Pl, P2, P3, a movement trajectory 3 defining a closed profile and at least a conveyor device 4 of the products to be palletised P1,P2,P3, mobile along the trajectory 3 and destined to collect and/or unload the products to be palletised from or to the first zone 2.

According to the invention, the first zone 2 comprises at least a stacker crane 5 positioned internally of the trajectory 3.

In the first zone 2 both the main products Pl and the secondary products

P2, P3 are advantageously stored. Further, the plant of the invention preferably comprises at least a second storage zone 6 arranged externally of the trajectory 3 and reachable by the conveyor device 4.

The second zone 6 is fixed with respect to the trajectory 3, and is destined to house the main products Pl moved by the stacker crane 5 and transported by the conveyor device 4.

In more detail, the second zone 6 comprises one or more roller planes 7 operated by force of gravity and filled by the conveyor device 4 with the main products Pl in order to enable an operator to access the products easily in case of necessity (following the man-to-goods concept). The plant 1 also comprises at least a pick-up zone 8, which is also arranged externally of the trajectory 3 and which can be reached by the conveyor device 4.

The pick-up zone 8 is destined to house the secondary products P2, P3 in order to enable an operator to remove only the units required for making up the pallet (following the good-to-man concept), such that the non-collected units are newly transferred onto the conveyor device 4 and thereafter onto the stacker crane 5.

As is known by a technical expert in the sector, the stacker crane 5 comprises a vertically-developing column 5a which moves horizontally along a first track 9. The track 9 can be positioned on the ground and develops between a pair of vertical storage units 10 having a plurality of storage levels located one above another and served by the stacker crane 5.

A cradle 5b is vertically slidably associated to the column 5a on which cradle 5b a mobile picking device 5c is positioned, which device 5c is mobile horizontally in a transversal direction to the development of the track 9 and is destined to pick and position the products to be palletised Pl, P2, P3 on the various levels of the vertical storage units 10.

The lowest storage level of each vertical storage unit 10 is advantageously accessible by the conveyor device 4 for moving the products to be palletised Pl, P2, P3 from and towards the vertical storage units 10. hi the preferred embodiment represented in the figures, in which two vertical storage units 10 are comprised, side-by-side and between which the stacker crane 5 is interposed, access is possible from each straight side of the trajectory 3 by means of the conveyor device 4 to the storage bays 10a positioned in proximity of the relative straight side. In more detail, the lowest storage level of each vertical storage unit 10 comprises a plurality of storage bays 10a, visible in figure 6, destined to support products to be palletised Pl, P2, P3 moved by the stacker crane 5. At least a part of the medium-use products P2 is preferably positioned on some of the storage bays 10a, while other storage bays 10a are left free for the movement and interchange of the various products to be palletised Pl, P2, P3 between the stacker crane 5 and the conveyor device 4.

Each storage bay 1 Oa is advantageously provided with relative movement means of the products to be palletised Pl, P2, P3 from and towards the storage bay 10a. Li more detail, the movement means with which each storage bay 10a is provided comprise a pair of chains 14 defining a rest plant for the products to be palletised Pl, P2, P3; each chain 14 is wound about a pair of cogwheels 15 freely rotating about the respective axes.

The conveyor device 4 advantageously comprises motor means temporarily connected to the movement means for activating the movement such as to bring the products to be palletised Pl, P2, P3 from the relative storage bay 10a onto the conveyor device and vice versa. In order to connect the motor means mechanically with the movement means, the conveyor device 4 must be positioned at the corresponding storage bays 10a, with the products Pl, P2 _> P3 to be palletised located on the rest plane. In more detail, the motor means comprise at least a motor element 16 and the movement means comprise at least a relative conduit 13 associable to the motor element 16.

The motor element 16, constituted for example by a shaft which can be activated to rotate about an axis thereof by a first motor group, is mobile alternatively in a nearing and a distancing direction from the relative storage bay 10a. In the embodiment illustrated in the figures, the motor element 16 is associated to a slide 30 which is linearly moved by a con rod- crank system, which is not illustrated in detail in the figures and which is activated in turn by a second motor group. More precisely, the motor element 16 is alternatively mobile between an engaged position, in which it is mechanically connected to the relative conduit 13 in order to rotate it about the axis thereof, and a free configuration, in which it is mechanically not engaged to the conduit. The motor element 16 preferably exhibits a first engagement zone 18a facing towards the inside of the trajectory 3 and destined to cooperate with the conduit 13 in the engaged configuration.

Ei the embodiment illustrated in figures 3, 4 and 5, the conduit 13 is mechanically connected to the pair of chains 14 by means of a first drive transmission system 19a. In the engaged configuration of the motor

element 16, the rotating movement of the motor 16 sets the chains 14 in rotation, on which the products to be palletised Pl, P2 and P3 rest and are drawn by friction towards the conveyor device 4. The rotation direction of the motor element 16 about the axis thereof can be inverted in order to facilitate the passage of at least the secondary elements P2, P3 not used in the composition of a mixed pallet from the conveyor device 4 newly onto the storage bay 10a, such as to position the medium- use products P2 and the low-use products P3 internally of the vertical storage units 10 by means of the stacker crane 5. The motor element 16 advantageously also exhibits a second engagement zone 18b, opposite the first engagement zone 18a and extending towards the outside of the trajectory 3. The second engagement zone 18b is destined to cooperate with the second storage zone 6 and with the pick-up zone 8. The conveyor device 4 further exhibits drawing means destined to facilitate passage of the products to be palletised Pl, P2, P3 from and to the conveyor device 4, mechanically connected in translation to the slide 30 and in rotation to the motor element 16 by means of a second drive transmission system 19b. In the embodiment illustrated in figures 3 and 5, the drawing means are constituted by a pair of chains 21, each of which is wound about a pair of cogwheels 22 that are mechanically connected to the motor element 16. The chains 21 define a support plane for the products to be palletised Pl, P2, P3 and are activated by the rotation of the motor element 16. The rotation direction of the chains 21 obviously depends on the rotation direction of the motor element 16.

The first zone 2 advantageously comprises at least an interchange station 11 of the products to be palletised Pl, P2, P3 served by the stacker crane 5 and destined to move the products to be palletised between the first storage

zone 2 and at least a storage area which is external of the trajectory 3 (not shown in the figures).

In more detail, the interchange zone 11 is preferably positioned at a certain height and is arranged at an endrun position of the stacker crane 5. The unloading station 11 can advantageously exhibit two or more interchange planes 11°, as shown in the embodiment illustrated in figure 1, in which two interchange planes 11a are arranged side-by-side and in succession in front of one or the two vertical storage units 10 represented. Obviously different arrangements of the interchange planes 11a are possible and will be easily intuited by technical experts in the sector.

In the following the process for making up mixed pallets according to the invention is described, especially in the use of a plant for supplying products to be palletised as described herein above and as represented in the accompanying figures of the drawings. The process of the invention is intended for the composition of mixed pallets comprising predefined quantities of products to be palletised. The process of the invention firstly comprises a stage of classification of a plurality of different types of products to be palletised Pl, P2, P3 into one or more high-frequency main products Pl and one or more less-frequently used secondary products P2, P3. The stage of classification preferably comprises a stage of sub-classification of the secondary products P2, P3 into medium use products P2 and low-use products P3. Thereafter a stage of storage of the main products Pl and the secondary products P2, P3 is performed in one or more respective support units, not visible in detail in the figures, such as containers, pallets or the like. As known to a technical expert in the sector, the support units positioned in the stores each contain, generally though not exclusively, a single type of

product, so that each main product Pl and each secondary product P2, P3 is stored internally of a corresponding support unit.

The process of the invention then comprises a stage of positioning the support unit, both of the main products Pl and the secondary products P2, P3, in the first vertically-developing automatic storage zone 2 on various storage levels located one above another. As described herein above, the first zone 2 comprises one or more vertical storage units 10 served by the stacker crane 5 positioned internally of the first zone. In more detail, the stacker crane 5 collects the support units of the products to be palletised Pl, P2, P3 from the interchange zone 11 and positions them in the first zone 2 on the various levels of the vertical storage units 10.

The positioning of the support units in the first zone 2 advantageously comprises a stage of arranging the support units of the secondary products P2, P3 at least at the lowest storage level of the vertical storage units 10 from which the movement of the products to be palletised Pl, P2, P3 is performed by means of the conveyor device 4.

Preferably only the support units of the medium-use products P2 are arranged at the lowest level of the vertical storage units 10, while the support units of the low-use products P3 are arranged on the other levels of the vertical storage units.

Since the lowest level of the vertical storage units 10 comprises a plurality of storage bays 10a, the arrangement of the support units of the medium- use products is performed on only some of the storage bays 10a, the other storage bays 10a being left free for the automatic movement of the other products to be palletised Pl and P3.

Following the positioning of the support units of the products to be palletised Pl, P2 and P3, the units are automatically moved at least from the first zone 2 towards the trajectory 3 of movement of the support units.

The movement of the support units of the main products Pl and the low- use products P3 is advantageously done using stacker crane 5, which picks the support units of the products to be palletised P land P3 from the vertical storage units 10 and positions them on the free storage bays 10a, from where they are picked by the conveyor device 4.

The support units of the medium-use products P2, which are already on the relative storage positions 10°, are directly moved by the conveyor device 4. Following the movement of the support units, they are then transported along the trajectory 3 which, as described above, defines a closed profile which externally delimits the first storage zone 2.

The transport of the support units of the main products Pl and the secondary products P2, P3 along the trajectory 3 is advantageously performed by the conveyor device 4 described herein above. In more detail, the conveyor device 4is positioned at one of the storage bays 10a and the motor 16 is brought into the engaged configuration to activate the movement means, thus drawing the support unit of a main product Pl or a secondary product P2, P3 onto the support plane thereof. Following the transport of the products to be palletised Pl, P2 and P3 by means of the conveyor device 3, a stage of unloading the support units of the main products Pl and the secondary products P2, P3 is performed, externally of the trajectory 3 such that the predefined quantities of the main products Pl and the secondary products P2, P3 can be collected for making up the mixed pallets. The process of the invention advantageously comprises also the performing of a stage of collecting the support units of the main products Pl in the second storage zone 6 positioned externally of the trajectory and accessible by an operator.

The discharge stage of the main products Pl is then performed in order to restock the second zone 6, from which the predefined quantity necessary for the composition of a relative mixed pallet is picked. The unloading of the support units of one of the main products Pl is preferably performed each time the stocks of the main product in the second storage zone 6 are finished.

The process of the invention thus comprises the performing of a plurality of movement stages from the first zone 2, for transport and unloading of the support units of the main products Pl up to the replenishing of the second storage zone 6, from which the predefined quantities of the main products for making up a mixed pallet are then picked.

The non-utilised elements of the main products Pl for making up a mixed pallet are left in the relative support units in the second storage zone 2 and are used later for making up further mixed pallets. The unloading of the support units of the secondary products P2, P3 is performed in the pick-up zone 8, also arranged externally of the trajectory 3 and reachable by an operator, again using the conveyor device 4. The predefined quantity of the secondary products P2, P3 required for making up a relative mixed pallet is directly collected by an operator in the pick-up zone 8.

In a case in which the operator collects only a part of the elements of the secondary products P2, P3 contained in the respective support units unloaded, the support units can be repositioned on the conveyor device 4, which newly returns them towards the storage bays 10a. The support units of the medium-use products P2 remain on the relative storage bays 10a and the support units of the low-use products P3 are moved by the stacker crane to be returned to the vertical storage units 10.

The displacements of the conveyor device 4 are thus used, especially, for the transport of the supporting units of the secondary products P2, P3 while the support units of the main products Pl are left in the second zone 6 up to when they are finished, thus limiting the movements of the conveyor device 4 necessary for the main products.

The described invention has been observed to attain the set aims and in particular it is stressed that due to the special reciprocal positioning of the automatic machines which make it up and the storage zones enable the production potential of the automatic machines to be best exploited. The plant enables high productivity to be attained in the making up of mixed pallets, also in the presence of numerous different types of products stored in a warehouse and a high fractioning of the products itself for each pallet to be realised. The invention as it is conceived in susceptible to numerous modifications and variants, all of which fall within the ambit of the inventive concept. Further, all the details are replaceable by other technically-equivalent elements. m practice the materials used, as well as the contingent forms and dimensions, can be of any kind according to needs without the invention thus forsaking the ambit of protection of the following claims.