Abstract:
A plant and a method for carrying out orderly arrangement of products in ranks along a packaging line, wherein an alignment device is set between a first conveyor belt and a second conveyor belt. The products arrive on the first belt in ranks with substantially disorderly transverse alignment and with longitudinal distances that may vary between the said ranks, and are accelerated to obtain, on the second belt, ranks aligned in an orderly way and properly spaced from one another.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates in general to a plant and a method for carrying out orderly arrangement of products in ranks along a packaging line. 
     In particular, the invention relates to packaging systems in which the products are arranged on a first conveyor belt according to ranks having substantially disorderly transverse alignment and with longitudinal distances that may vary between said ranks. From this first conveyor belt, the ranks must be transferred onto a second conveyor belt according to orderly ranks in a transverse direction and must be spaced longitudinally at pre-set distances. 
     2. Discussion of Related Art 
     The term “longitudinal” is meant, here and as follows, the direction parallel to the direction of advance of the conveyor belts. The term “transverse” is meant, here and as follows, the direction perpendicular to the longitudinal one. 
     A possible example of non-limiting application of the present invention is that of plants for packaging baked products coming from an oven in the foodstuff industry. The conditions of feed in ranks occur, in fact, downstream of an oven for the baking of foodstuff products, such as small cakes, tarts or the like, in which the-products at output from the oven are deposited according to irregular ranks on a conveyor belt for the subsequent steps of selection and packaging. Prior to the packaging step, the products must in any case arrive aligned in regular ranks and must be spaced at equal pre-set distances. 
     To obtain alignment of the products in ranks, as well as the right spacing as required, it is known to cause the products, which are possibly pre-selected, to advance in disorderly ranks up to a pair of conveyor belts, with the upstream conveyor belt operating in an intermittent or in a continuous way, and the downstream conveyor bell generally operating in a continuous way. At each rank of products which is transferred from the upstream conveyor belt to the conveyor belt immediately following it, a transverse blade drops down and temporarily stops the products until a rank is obtained that is perfectly aligned and spaced from a rank already present on the same downstream belt. 
     It is evident that this type of solution does not enable high rates of production to be sustained. This drawback is even more important in the cases where, according to the type and dimensions of the products, the orderly ranks must be spaced at intervals from one another at a considerable distance. 
     SUMMARY OF THE INVENTION 
     In general, one aspect of the present invention to provide a plant and a method that enable orderly arrangement of products in ranks along a packaging line to be carried out in an extremely fast way. Another aspect of the present invention is to provide a plant and a method such as the ones cited above, which enable a high productivity to be sustained irrespective of the distance that it is desired to obtain between the ranks of the products. 
     These aspects are achieved by the present invention, which relates to a plant for carrying out orderly arrangement of products along a packaging line, of the type comprising at least one alignment device arranged along the packaging line, and wherein the packaging line comprises at least one first conveyor belt, arranged upstream of the at least one alignment device, on which the products are set in ranks with substantially disorderly transverse alignment and with longitudinal distances that may vary between the ranks themselves, and at least one second conveyor belt, arranged downstream of the at least one alignment device, on which the products must be set aligned according to orderly ranks spaced at pre-set distances, characterized in that the alignment device comprises means for accelerating the ranks of products during their passage from the first conveyor belt to the second conveyor belt. 
     In this way it is possible to obtain alignment of the products in orderly ranks and proper spacing thereof without affecting the rate of arrival of the ranks at the alignment device, or in other words, irrespective of the rate of production. 
     The means for accelerating the ranks of products comprise one or more blades set in motion along at least one respective pre circuit by means of a motor driven in a controlled way. Each blade, while accelerating a rank, also aligns the products of the rank itself and accompanies them on the second conveyor belt. 
     The second conveyor belt is driven in motion at a higher speed than the first belt. By varying the speed between the conveyor belts, it is thus possible to obtain proper spacing between successive ranks of products. 
     According to a possible embodiment of the present invention, the means for accelerating the ranks of products comprise one or more distinct circuits, on each of which at least two blades are set in motion. The blades of one circuit are preferably set in motion by a motor controlled independently of the motor associated to another of said circuits. 
     In this way, at least one blade along one of the two circuits is always ready to intervene for carrying out alignment of a rank that is arriving at the alignment device when a blade associated with the other of he two circuits is carrying out alignment of a rank that arrived at an immediately preceding instant. 
     Each plant may of course be equipped also with two or more alignment devices, each set between consecutive conveyor belts, which are driven at different speeds. This allows to space ranks at increasing distances until, for example, a desired particularly long interval is obtained between one rank and the next, or else intervals that are in any case more reduced can be obtained without having to force the acceleration of the products during the subsequent steps of alignment/spacing. 
     The invention also relates to a method for carrying cut orderly arrangement of products along a packaging line by means of at least one alignment device arranged along the packaging tine, wherein the packaging line comprises at least one first conveyor belt, arranged upstream of the above-mentioned at least one alignment device, on which the products are set in ranks with substantially disorderly transverse alignment and with longitudinal distances that may vary between the ranks, and at least one second conveyor belt, arranged downstream of the at least one alignment device, on which the products must be set aligned according to orderly ranks spaced from one another at pre-set distances, characterized by providing acceleration of the ranks of products during their passage from the first conveyor belt to the second conveyor belt. 
     The method envisages, in particular, that a blade associated with one of the circuits will be stationary in a stop position, waiting to be operated in order to accelerate at least one rank of products. When a blade is moved from the stop position for alignment and acceleration of the ranks towards the second conveyor belt, at least one other blade associated to the other of the two circuits is shifted into the stop position. In this way it is always possible to intervene for aligning an immediately subsequent rank. 
     A blade is moved from the stop position when a distance is detected that is equal to or greater than a pre-set distance between two adjacent ranks on the first conveyor belt, Moreover, a blade is moved from the stop position when there is detected a longitudinal dimension of a rank equal to or smaller than a pre-set length. 
     It is thus possible to select the ranks that may be properly aligned and space them from those that are, instead, so disorderly as not to enable intervention of the alignment device. The detection of such events is then used for directing in the direction of a separate conveying line the ranks that have not been aligned and spaced. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further characteristics and advantages of the present invention will emerge more clearly from the following description, which is provided purely by way of illustrative and non-limiting example, with reference to the attached drawings, in which: 
     FIG. 1 is a detailed elevation view of an alignment device in a plant according to a possible embodiment of the present invention, with a blade shown in various positions along the respective circuit; 
     FIG. 2 is an enlarged and simplified view of a detail of FIG. 1; 
     FIG. 3 is an enlarged and simplified view of another detail of FIG. 1; 
     FIGS. 4A-8A are schematic elevation views of some of the operating steps of a plant according to the present invention; and 
     FIGS. 4B-8B are schematic plan views of the steps corresponding to those illustrated in FIGS.  4 A- 8 A. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to FIG. to  3 . a plant according to the present invention comprises an alignment device  10  arranged along a packaging line between a first conveyor belt  1  and a second conveyor belt  2 . The conveyor belts are set in motion in a continuous way with respective speeds V 1  and V 2  that are different from one another, in particular with the speed V 2  of the belt  2  greater than the speed V 1  of the belt  1 . By appropriately regulating the speed of the belt  1  and of the belt  2  it is possible to impart the desired interval between consecutive ranks on the belt  2 . 
     To accelerate the ranks of products from the belt  1  to the belt  2 , there are provided one or more blades  20   a,    20   b  and  30   a,    30   b  (see, for example, FIGS.  4 A- 8 A), of which FIG. 1 represents, for instance, just one, designated with the reference number  20   a,  in the various positions  201 ,  202 ,  203 ,  204 ,  205 ,  206 ,  207  and  208  of the respective circuit. 
     Upstream of the alignment device  10 , in a position corresponding to the passage of the products on the conveyor belt  1 , there are provided sensor means  5 , which enable detection of information on the distance between the ranks of adjacent products and the space occupied by each rank on the first conveyor belt  1  in the longitudinal direction. This information is transmitted in the form of signals to a control unit (not shown), which accordingly controls the driving motors of the blades  20   a,    20   b  and  30   a,    30   b.    
     The blades  20   a  and  20   b  are set in motion on a first circuit and driven by a first motor  120 , while the blades  30   a  and  30   b  are set in motion on a second circuit, distinct from the first, by a second motor  130  driven independently of the first. The motors  120  and  130  may be. —for example, of the brushless type of in any case of any type which will enable control of speed and acceleration. 
     With reference now in particular to the views of FIGS. 2 and 3, each blade, for example the blade  20   a,  is mounted on a pair of supporting elements  40  (just one of which is visible in FIGS. 2 and 3) arranged at its ends. Each supporting element  40  comprises a portion with a parallelogram structure formed by arms  41  and  42 . which are each hinged at one of their ends to a drawing block  43  and at the other of their ends to a block  44  for fixing of the blade  20   a.  This allows the blades  22   a,    20   b,    30   a,    30   b  to be maintained in a position substantially perpendicular to the conveyor belts  1  and  2  at least in a position corresponding to the passage between one belt and the other, as shown for the blade  20   a  in FIG. 3 in the positions  204  and  205 . 
     With particular reference to FIG. 2, in which the blade  20   a  is shown in the position  203 , the drawing block  43  of each supporting element  40  is connected to a chain, represented schematically by the line  50  and is set in motion by a wheel  60  connected to one of the two motors  120  or  130 , once again by means of belts or chains, represented schematically in FIG. 1 by respective dashed-and-dotted lines  121  and  131 . 
     Each supporting element  40  comprises a follower member, namely a wheel  70  mounted on the arm  42 , which bears in a mobile way upon a rail  80  for defining the path of the circuit of each blade. The rail  80  comprises, in particular, a portion  85  (FIG.  3 ), along which the blade is made to advance in the proximity of the belts  1  and  2  to enable accompaniment, during acceleration, of the ranks of products from the conveyor belt  1  to the conveyor belt  2 . The portion of rail  85  thus defines an active portion of path along the circuit. 
     As a whole, considering the blades  20   a  and  20   b,  each blade is mounted at its ends on two supporting elements  40  fixed to two respective chains  50  placed between corresponding wheels  60 . The blades  20   a  and  20   b  are spaced at equal distances along the chain (or along the circuit). The same applies to the blades  30   a  and  30   b,  which are, however, mounted on supports distinct from those of the blades  20   a  and  20   b,  as likewise the chains and the respective wheels are distinct. 
     FIGS. 4A and 4B illustrate one of the steps of the operating cycle of the plant. On the conveyor belt  1 , which moves at a speed V 1  three ranks R 1 , R 2  and R 3  are visible which are set with substantially disorderly alignment In the step represented, the blade  20   a  of the first circuit has already been set in motion at the same speed V 1  as that of the belt  1 . Since the blades  20   a  and  20   b  are connected to the same chain  50 , they move at each instant according to the same law of motion. 
     The blade  30   a  associated to the second circuit is instead stationary in the waiting position occupied previously by the blade  20   a.  Also in this case, the blades  30   a  and  30   b  are connected to the same chain and obey the same law of motion. 
     Operation of the blade  20   a  is determined on the basis of the signals received from the sensor means  5  (FIG. 1) which have enabled determination of the conditions of intervention on the rank R 1 . In practice, to enable the alignment operation, the distance between the ranks R 1  and R 2  must be greater than a pre-set minimum distance, and the longitudinal dimension of the rank R 1  must be equal to or smaller than a pre-set length. These pre-set parameters may also be varied according to the type and dimensions of the products to be treated. 
     The blade  20   a  which accompanies the rank R 1  is then accelerated until it reaches at least a speed that is equal to or slightly higher than the speed V 2  of the second conveyor belt  2 , as indicated in FIGS. 5A and 5B, so as to enable alignment of the products in the rank R 1  during their passage from the conveyor belt  1  to the conveyor belt  2 . The blade  30   a  is, instead, still stationary, waiting to be actuated for one of the successive ranks. 
     As may be noted in FIGS. 6A and 6B, the rank R 1  is accompanied by the blade  20   a  on the conveyor belt  2  in a condition of perfect alignment, with the blade  20   a  which is kept in motion at the same speed V 2  as that of the belt  2 . 
     In this step, there moreover arises the condition for intervention on the next rank R 2  by the blade  30   a,  which was previously at rest in the waiting condition. In other words, as already explained previously, the sensor means  5  (FIG. 1) have detected that the distance between the rank R 2  and the rank R 3  is greater than or equal to a pre-set distance and that the rank R 2  has a longitudinal dimension that is equal to or smaller than a pre-set length. 
     The blade  30   a  is then operated to move towards the portion of rail  85  until it reaches the speed V 1 , to enable its insertion between the rank R 2  and the rank R 3 . It should be noted that also the other blade  20   b  connected to the same chain to which the blade  20   a  is connected moves at a speed V 2 . and thus moves away from the blade  30   b,  which follows it at a lower speed V 1 , the latter blade being connected to the same chain to which the blade  30   a  is connected. Consequently, no interference can occur between the blades associated to the two distinct circuits, since the blade that precedes always moves at a speed higher than that of a blade that follows. 
     In FIGS. 7A and 7B there is represented the step in which the blade  30   a  moves at the speed V 2  along the active portion of the circuit, namely in a position corresponding to the portion  85  of the rail  80 , for aligning the rank R 2  and accompanying it on the conveyor belt  2 . The blade  30   a  is then lowered towards the conveyor belts  1  and  2  until it arrives in the proximity of the same and is made to advance into a substantially perpendicular position to enable its insertion in the free space between the ranks R 2  and R 3 . 
     In this step, the blade  20   a  has already abandoned the active portion of the circuit and lifts up so as not to interfere with the rank R 1  already aligned. The blade  20   a  is then accelerated up to a speed V 3 , greater than V 1  and V 2 , to enable the other blade  20   b  of the same circuit to reach, in the shortest time possible, the waiting position, or stop position, that will enable possible intervention of the same blade  20   b  on the next rank R 3 . Also in this case, the blade  20   b  moves at a speed V 3  greater than the speed V 2  at which the blade  30   b  moves on the other circuit. 
     FIGS. 8A and 8B illustrate the situation immediately subsequent to the above, in which the blade  30   a  moves at a speed V 2  during completion of the step of alignment of the rank R 2  during transfer of the latter onto the conveyor belt  2 , while the blade  20   b  has already reached its stop position and is hence stationary, waiting for the condition to arise for carrying out alignment of a subsequent rank, for example the rank R 3  or any rank subsequent thereto for which the conditions already described previously with reference to the ranks R 1  and R 2  arise. 
     The embodiment of the plant according to the present invention has been illustrated herein purely by way of example and is not to be understood in a limiting sense. In particular, a plant according to the present invention may comprise two or more alignment devices, which are set along a packaging line between a number of consecutive conveyor belts driven at different speeds. This could enable the desired spacing of the ranks of products to be obtained on the final belt, limiting the variations in speed to which the various members in motion are subjected.