APPARATUS FOR THE TEMPORARY ACCUMULATION OF PRODUCTS WITHIN PRODUCTION LINES AND RELATIVE ACCUMULATION METHOD ooooooooo

FIELD OF THE INVENTION

The present invention refers to an apparatus and relative method for the temporary accumulation of products between section upstream and a downstream of a production line.

More specifically, the invention refers to an accumulating apparatus of the type that includes flexible closed cycle transmission means which support containers of the products of the production line, fixed axis deflection elements of said transmission means and mobile axis deflection elements of the transmission means, at least one station for loading and unloading of the products to or from said containers and actuators capable of causing the movement of the transmission means. DESCRIPTION OF THE PRIOR ART

Apparatuses of this type for the temporary accumulation of products within production lines are described e.g. in US 4.142.626, in US 6.053.304, in WO2004/080860 or in EP 1371583. The latter have in common that they provide a first series of fixed axis deflection wheels arranged in the lower part of the structure, a second series of fixed axis wheels arranged on the top of the structure and mobile axis sets of wheels in intermediate positions between the first fixed axis series of wheels and the second fixed axis series of wheels. This feature allows for such apparatuses to include a quantity of products varying as function of the position assumed by the mobile axis sets of wheels, the

movement of which does nothing else than increase the portion of transmission means that support loaded containers, with the consequent reduction of the portion that supports unloaded containers and vice versa. This type of accumulating apparatuses extensively is used in the paper sector. In particular in combination with cradle shaped product containers they are often used for the transport of coils largely varying in diameter and number. As is easy to understand, for a certain type of transported product the total accumulating capacity depends on the length of the transmission means and thus on the overall dimensions of the apparatus. Due to this reason the apparatuses of this type often are so bulky and complex that they need to be completely assembled at the place of installation, an operation that may take even weeks to be completed, with extremely high cost of transport and labour to be incurred.

In particular, besides that the presence of a high number of fixed axis deflection elements in the upper part of the structure has the double disadvantage of complicating the assembly operations and not preventing excessive heights of the structure from being reached.

Also the functions of loading and unloading of the products which normally take place according to a first-in-first-out logics in orthogonal direction to the direction of longitudinal extension of the containers of the products in many cases limit the transversal dimensions of the structure to be confined within a production line.

This last feature of the apparatuses of the prior art, together with other factors well known by the exports in the field often prevent them from being used in the

case of prism-shaped products as quite often found in the field of packing and packaging.

The above reasons explain the need of looking for solutions for the temporary accumulation of products which overcome the above mentioned limits of the apparatuses of the prior art.

SUMMARY OF THE INVENTION

A purpose of the present invention is to provide an apparatus for the temporary accumulation of products within production lines with an extremely simple and flexible structure that allows for extremely short assembly and commissioning times.

A further purpose of the present invention is to provide an apparatus for the temporary accumulation which is capable of reaching a very high accumulating capacity at a comparatively small footprint.

A further purpose of the present invention is to provide an apparatus for the temporary accumulation of a vast scope of products.

Another purpose of the present invention is to provide a very simple and rational method for the temporary accumulation within productions lines that allows for the construction of very economic apparatuses with a very simple structure.

The above purposes are reached by means of an apparatus for temporary accumulation arranged between an area upstream and an area downstream of a production line, comprising flexible closed cycle transmission means which support containers of the products of the production line, at least one station for loading and unloading of the products to or from said containers and actuators

capable of causing the movement of the transmission means, wherein the transmission means extend between a first series of fixed axis deflection elements, a first set of mobile axis deflection elements, a second series of fixed axis deflection elements and a second set of mobile axis deflection elements, said sets of mobile axis deflection elements being connected with each other by flexible closed cycle transmission means and further reciprocal connecting elements.

These further reciprocal connecting elements are advantageously flexible and substantially not expandible and connect the supports of said first set of mobile axis deflection elements by means of further fixed axis deflection elements to the supports of said second set of mobile axis deflection elements. According to a preferred embodiment said closed cycle transmission means pass through a loading station, are deflected by the first set of mobile axis elements, pass through an unloading station, pass through at least one fixed axis deflection element and then move on again to the loading station. Moreover the apparatus advantageously includes first actuators capable of causing the movement of the transmission means at the loading station, and second actuators capable of causing the movement of the transmission means at the unloading station, first and second actuators that are positioned in a manner to act, on the path of the closed cycle transmission means, alternatingly on the first set of mobile axis deflection elements and on the second set of mobile axis deflection elements in order to separate the movement of the containers at the loading station from the movement of the containers at the unloading station.

As alternative a single actuator may be provided capable of reversing motion and causing the movement of the transmission means close to a single loading and unloading station, with the second actuators being substituted by braking elements in a position to locally lock the movement of the transmission means. Moreover in the preferred embodiment the feeding direction of the products to the loading station from the section upstream of the production line is parallel to the longitudinal axis of said product containers as well as with the direction of removal of the products discharged in the unloading station towards the section downstream of the production line.

Moreover locking means are provided that are capable of interrupting the product flow towards the loading station, with the actuation of said locking means being synchronized with the actuation of the actuators capable of causing the movement of the transmission means at the loading station. Auxiliary conveying means feed the products from the end of the section upstream of the production line to the unloading station and analogous auxiliary conveying means feed the products from the unloading station to the section downstream of the production line. The auxiliary conveying means include one or several parallel runs positioned and dimensioned in such a way as to permit the passage of the containers due to the space between appropriately spaced longitudinal bars of which the containers are made.

The above mentioned purposes are also obtained by a method for the temporary accumulation of products in an area between a section upstream and a section downstream of a production line where events are taking place such as:

- arrival of the products from said section upstream of the production line and feeding of said products to a loading station;

- loading of the products on containers supported by closed cycle transmission means which extend between sets of fixed axis deflection elements and sets of mobile axis deflection elements;

- movement of said containers to an unloading station;

- unloading of said products from said containers and transfer to said section downstream of the production line; characterized by the fact that the movements of the containers to the unloading station take place as function of the movement of the first and of the second set of mobile axis deflection elements, said movements being reciprocally defined by the transmission means and by means of further reciprocal connecting elements.

Advantageously the movements of the first and of the second set of mobile axis deflection elements are induced by actuators which control loading and unloading of the products and due to which the loading and the unloading operations take place as a completely separate event with the feeding speed of the containers at the loading station being separate from the feeding speed of the containers at the unloading station.

Moreover, still advantageously, the movement of the containers at the loading and unloading station takes place intermittingly by discrete displacements, with the value of said discrete displacement being equal to the space between two consecutive containers.

Moreover a preferred embodiment of the invention provides for the feeding of the products to the loading station in a direction parallel to the longitudinal axis of said containers, and the same occurs for the unloading operation for the transfer of the products to the section downstream of the production line. Moreover it is advantageously provided that the feeding of the products to the loading station is interrupted during the displacement of the containers at the loading station, whilst the transfer of the products to the section downstream of the production line simply takes place by the containers passing through the unloading station, a passage during which the products remain placed on said auxiliary conveying means.

The particular positioning of the mobile and fixed axis deflection elements that can be carried out with the above outlined apparatus allows for a great design simplicity which implies a reduced cost of the structure and particularly short assembly and disassembly times of the latter.

Moreover the structure may extend in height beyond that of the apparatuses of the prior art allowing for a greater accumulating capacity and a smaller footprint. The advantages of the method and of the apparatus of the invention are particularly obvious also with regard to the extreme simplicity and rationality of the loading and unloading of the products that allow for a further reduction of the overall dimensions and a high speed of loading and movement of the products themselves. BRIEF DESCRIPTION OF THE DRAWINGS

These and other advantages in connection with the apparatus and the method of the invention are moreover still easier understandable by illustrating a not

exhausting example of an embodiment of the invention as described below with the aid of the attached drawings, wherein:

- fig. 1 represents a diagrammatic front view of an apparatus according to the invention;

- fig. 2 represents an likewise diagrammatic lateral view of the apparatus of fig.1 ;

- fig. 3 represents a view from above of the apparatus of fig.1 ;

- fig. 4 represents a detail of fig.2;

- fig. from 5 to 7 represent a front, lateral view and a view from above of a component of the apparatus of fig.1 ;

- fig. from 8 a 10 represent a front, lateral view and a view from above of a further component of the apparatus of fig.1 ;

- fig. 1 1 represents a view from above of two particular operating areas of the apparatus and of the method of the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to fig. 1 , 10 indicates a complete conveying apparatus according to the invention.

The apparatus 10 includes a supporting structure, 1 1 , mainly composed of columns, 12 and cross beams, 13, that support deflection elements which define the path of closed cycle flexible transmission elements, 14 and 15.

In particular the transmission means 14 develop between a first series of fixed axis deflection wheels, 16, arranged in lowest part of the structure, a first mobile axis wheel, 18, a second series of fixed axis wheels, 19, also arranged in the lower part of the structure, and second mobile axis wheels, 20.

With reference to fig. 2 it can be observed that the wheels 16, 18, 19 and 20 are anchored to the left columns, 12, of the structure, and the transmission means 14 thus run in parallel with that side. The transmission means 15 run on an identical path close to the right side of the structure, deflected by a first series of fixed axis wheels, 21 , a first mobile axis wheel, 22, a second series of fixed axis wheels, 23, and second mobile axis wheels, 24. Flexible connecting means, 25, deflected by pulleys 26 and 27 anchored to the upper part of the structure 1 1 , reciprocally link the movements of the first mobile axis wheel 18 to those of the second wheels 20 connected in order to form a solidarily moving set.

Analogously flexible connecting means 28, deflected by pulleys, 29 and 30, reciprocally link the movements of the mobile axis wheel 22 to those of the set of solidarily mobile axis wheels 24.

Supporting means, 31 , connect in this example of an embodiment the mobile axis wheel 18 to the mobile axis wheel 22, providing thereby also for the solidary movements of the set of mobile axis wheels 20 with the set of mobile axis wheels 24.

The apparatus includes first actuators, 50, indicated by M1 , capable of causing the rotation of one of the fixed axis deflection elements 16, and second actuators, 51 , indicated by M2, capable of causing the rotation of one of the fixed axis deflection elements 19. The simultaneous or alternating actuation of the above actuators causes the movement of the transmission means 14 and possibly displaces due to the connections by the means 25 the wheels 18 and 20. A series of further deflection elements, for simplicity of representation not

shown in the figures, transmits the motion of the wheels 16 to the wheels 21 and from the wheels 19 to the wheels 23, thus synchronizing the movement of the transmission means 15 to that of the transmission means 14.

These means, 14 and 15, support containers, 32, represented in figure 1 in some of the positions which they assume during the movement of the transmission means themselves.

The containers 32 shown in detail in the figures from 5 to 7 are composed of a series of longitudinal bars, 33, linked by a cross bar 34. Suspension arms, 35 and 36, rigidly connected to the bars 33, are arranged at the opposed longitudinal ends of the container by which the container is suspended from the bolts, 37 and 38, which are part of the respective transmission means 14 and

15.

As can be noted in the figures 2 and 3, the apparatus moreover includes auxiliary conveying means, 60, capable of transferring the products, 61 , from a section upstream of the production, 62, to a loading station, 63; further auxiliary conveying means, 64, are capable of transferring the products from an unloading station, 65, to a section downstream of the production line, 66.

Said auxiliary conveying means, 60 and 64, better shown in the figures from 8 to 10, include parallel conveying belts, 67, actuated by means of a geared motor, 68, and anchoring means, 69, for anchoring to the structure 1 1. The conveying belts 67 are spaced in a way to allow for the passage of the longitudinal bars, 33, of the containers 32.

For a better understanding, the loading and unloading areas, 63 and 65, are shown in an amplified view from above in figure 1 1 , wherein the auxiliary

conveying means, 60 and 64, with the corresponding conveying belts 67 and geared motors, 32, with the corresponding longitudinal bars, 33, and the suspension arms, 35 and 36, can be noted.

As can be observed in the detail of fig. 4, the auxiliary conveying means 60 are provided with locking means, 70, including an actuating cylinder, 71 , and a profiled bar, 72, capable of locking the feed of the products 61.

The accumulating method according to the invention controls the functioning of the apparatus as follows.

The products, 61 , arrive at the apparatus by means of a conveying belt, 62 being part of the section upstream of the production line and access by means of the auxiliary conveying means, 60, to a loading station, 63, of the apparatus at which a container 32 is positioned.

After a defined number of products have been transferred to the loading station, the locking means 70 are activated and then the first actuators, 50, synchronized with them which allow for the lifting of the container 32 for the positioning of the next container into the loading position.

The containers 32 intermittently lifted by the movement of the transmission chains 14 and 15 by discrete feed steps equal to the distance between two successive containers, pass the mobile axis sets of wheels 20 and 24 in order to return then downwards to the unloading station 65 at the passage of which the products are discharged leaving them on the auxiliary conveying belts, 64, from where they are transferred to the conveying belt, 66, which is part of the section downstream of the production line.

The empty containers then continue their way over the various fixed and mobile axis deflection wheels until returning to the loading station 63.

It has to be noted, however, that this type of movement takes place if together with the first actuators, 50, also the second actuators, 51 , are actuated so that the axes of the wheels 18, 20, 22 and 24 remain locked and only the transmission means 14 and 15 are moving on.

In a different way the wheels 18 and 22 are pulled downwards lifting the wheels

20 and 24 and increasing the number of loaded containers 32, including between the loading station 63 and the unloading station 65, if the actuators 51 remain locked during the actuation of the means 50.

If however only the motor 51 is actuated, obviously the wheels 20 and 24 will move downwards and in this case only an unloading operation will take place.

Thus due to the presence of the two independent motors 50 and 51 loading and unloading take place as completely separate operations.

The particular path followed by the transmission means 14 and 15 and the arrangement of the deflection elements allow for maintaining the loading and the unloading station at very close distance, a fact that favours the feeding of the products in parallel to the direction of the longitudinal extension of the containers.

Loading and unloading take place in an extremely simple way due to the presence of containers and auxiliary conveying means designed for optimizing and speeding up these operations.

Also the movement of the mobile axis wheels is obtained in an extremely simple way, thus allowing for likewise simple and fast assembly and disassembly, maintenance and tuning operations.

These and other advantages visible at first sight to the experts in the field are safeguarded also in the presence of modifications or variants to the above.

Of course the number and the position of the deflection elements, whether those with fixed axis or those with mobile axis, could differ and generate different paths of the transmission means 14 and 15 which also could be arranged on perfectly parallel paths instead of being offset as in the described example of embodiment.

The loading and unloading station could be arranged in different positions, also at the two opposite ends of the structure as is normally the case for the apparatuses of the prior art, and be fed in an orthogonal direction referred to the direction of longitudinal extension of the containers which themselves could have other forms, dimensions and connecting means to the transmission means as illustrated above.

Moreover a single motor, 50 or 51 , equipped with reversing motion could be provided, incorporating instead of the other motor a simple braking element. In this case the loading station would coincide with the unloading station, thus the production line section downstream of the apparatus resulting aligned with the downstream line section.

The actuation of the motor(s) could take place not intermittently but continuously at constant or variable speed.

The locking means, 70, could be shaped and actuated in a different way referred to what is provided for in the described example, always safeguarding the main purpose of preventing the feed of the products along the auxiliary conveying means with the loading of the container being present in the loading station completed and having to shift it in order to replace it by an empty container.

These and other variants or modifications can be applied to the apparatus and the method relative to the invention for the temporary accumulation of products within production lines being always protected by the claims as defined below.