Abstract:
A unit for feeding an ordered succession of products to an unloading station comprises: an arranging device including a first and a second conveyor, each constituting a first and a second conveyor portion on a feed path whose total length is the sum of the two portions that complementarily vary in length relative to each other; a device for feeding the products to the first conveyor in sets; a transfer device located between the conveyor portions, coupled to the conveyors and designed to complementarily vary the lengths of the portions. The transfer device comprises two resilient belts that transfer the products from the first to the second portion. The feed device is cyclically mobile and, consequently, the first conveyor and the transfer device are cyclically mobile according to a law of motion and timing dependent upon the cyclic motion of the feed device.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a unit for feeding an ordered succession of products to an unloading station.  
           [0002]    The invention is advantageously used to feed products such as bars of soap, sweets and the like to a wrapping machine, to which the present specification refers but without thereby restricting the scope of the inventive concept.  
           [0003]    Installations for the production and packaging of products of this kind usually include wrapping machines which must receive the products to be wrapped in ordered succession, that is to say, suitably spaced, and dispensing devices which feed products in a continuous stream. It is therefore necessary to space the products out during their transfer from the dispensing device to the wrapping machine.  
           [0004]    In the art, feeding devices used to arrange products in ordered fashion for feeding to an automatic machine transport the products in succession on a first conveying device which moves in one direction at a first speed and which comprises a first, variable length conveyor portion extending from a loading station to a mobile transfer station. An ordered succession of the products are then transported on a second conveying device which moves at a second speed and which comprises a second conveyor portion of variable length to complement the first conveyor portion. The lengths of the two conveyor portions are varied by an adjusting device according to the position of the products moving on the first conveying device. Thanks to these devices, a continuous scrambled stream of products moving on the first conveyor can be arranged in way that makes the products suitable for subsequent handling.  
           [0005]    If products are fed to the first conveyor not continuously but by feeding means that impart on the first conveyor a movement that is closely linked to the predetermined law of motion that governs the feeding means themselves, devices of the above mentioned type have proved to be unsuitable to arrange the products feeding out towards an unloading station and to correctly adjust their spacing as they are dispensed to the wrapping machine.  
           [0006]    The aim of the present invention is to provide a unit for feeding the products to an automatic machine even when the products are fed to the first conveyor according to a law of motion imparted by respective feed means.  
         SUMMARY OF THE INVENTION  
         [0007]    Accordingly, the present invention provides a unit for feeding an ordered succession of products to an unloading station, comprising an arranging device comprising a first and a second conveyor belt each constituting a first and a second portion of a feed path that has a defined total length and each portion being complementarily variable in length relative to the other, means for feeding the products to the first conveyor, a transfer station located between the two portions and comprising a carriage coupled to the two conveyors to complementarily vary the lengths of the two portions, transfer means mounted on the carriage and designed to transfer the products from the first to the second portion, wherein the feed means are cyclically mobile to transfer the products to the first conveyor in sets consisting of a predetermined number of products, the first conveyor and the transfer means being cyclically mobile according to a law of motion and timing dependent upon the cyclic motion of the feed means. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    The present invention will now be described with reference to the accompanying drawings, which illustrate a preferred embodiment without limiting the scope of the inventive concept, and in which:  
         [0009]    [0009]FIG. 1 is a scaled-down, schematic side view, with some parts in cross section and others cut away, of a unit for feeding an ordered succession of products made in accordance with the present invention and illustrated in one stage of its operation;  
         [0010]    [0010]FIGS. 2 and 3 are schematic side views, with some parts in cross section and others cut away, of the unit for feeding an ordered succession of products of FIG. 1 illustrated in two successive stages of its operation;  
         [0011]    [0011]FIGS. 4 and 5 are partial plan views, with some parts cut away for clarity, of the unit shown in FIGS. 1 and 2, respectively;  
         [0012]    [0012]FIGS. 6 and 7 are a schematic side view, with some parts cut away for clarity, and a plan view, respectively, of a detail of the unit shown in FIGS. 1 and 3 in a stage of its operation different from that illustrated in FIGS.  1  to  5 ;  
         [0013]    [0013]FIGS. 8 and 9 are, respectively, a schematic side view, with some parts cut away for clarity, and a plan view of the detail shown in FIGS. 6 and 7 in a different stage of its operation. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0014]    With reference to FIGS. 1, 2 and  3  the numeral  1  denotes in its entirety a unit for feeding an ordered succession of products  2  to an unloading station, which is schematically illustrated as a block  3 .  
         [0015]    The unit  1  comprises an arranging device  4  designed to receive a succession of products  2  grouped in sets  5  consisting of a predetermined number of products  2 . The arranging device  4  comprises a first and a second conveyor belt  6  and  7  positioned in series and substantially horizontal, the first of which, namely the conveyor  6 , is designed to receive the products  2  from a feed device  8 , while the second conveyor  7 , is designed to feed the products  2  in ordered succession to an automatic machine, which is not illustrated, through an unloading station  3 .  
         [0016]    The conveyors  6  and  7  consist of belts  9  and  10  looped around a plurality of pulleys labeled  11 - 14  for the first conveyor  6 , and  15 - 19  for the second conveyor  7 , the pulleys being rotatable about respective axes which are parallel to each other and transversal to the feed direction, labeled  20 , of the conveyors  6  and  7 . The numerals  21  and  22  denote tensioning and transmission pulleys of the first conveyor  6 .  
         [0017]    In the embodiment illustrated in FIGS. 1, 2 and  3 , the pulleys  12 ,  13 , and  14  of the conveyor  6  and  15 ,  16 ,  17  and  18  of the conveyor  7  are idle driven pulleys, while the pulleys  11  and  19  are drive pulleys with respective motors, labeled M 1  and M 2 , which drive the conveyors  6  and  7  at a defined speed, respectively.  
         [0018]    The belt  9  of the first conveyor  6  has a succession of pockets  23  to contain the products  2  and formed by a plurality of protrusions  24  uniformly distributed along the belt  9  with a space p 1  between each one and the next. Similarly, the belt  10  of the second conveyor  7  has a succession of pockets  25  to contain the products  2  and formed by a plurality of protrusions  26  uniformly distributed along the belt  10  with a space p 2  between each one and the next, which in the embodiment illustrated, is substantially the same as the space p 1 , but which could, if necessary, differ from it. The size of the pockets  23  and  25  depends on the size of the products  2  so that the latter sit snugly inside them and are restricted in movement either completely or within well-defined limits, thus guaranteeing the correct operation of the automatic machine.  
         [0019]    As shown in FIGS. 1, 2 and  3 , the pulleys  12  and  14  of the first conveyor  6  are end transmission pulleys and form on the corresponding belt  9  a forward branch  27  and a return branch  28 , the former comprising a conveyor portion  29  extending between the pulleys  11  and  12 . Similarly, the pulleys  15  and  18  of the second conveyor  7  are end transmission pulleys and form on the corresponding belt  10  a forward branch  30  and a return branch  31 , the former comprising a conveyor portion  32  extending between the pulleys  15  and  18 .  
         [0020]    The conveyor portions  29  and  32  form part of a path P of defined length along which the products  2  are fed in the direction  20  from the feed device  8  to the unloading station  3 , and the contiguous ends of the conveyor portions  29  and  32  form between them a transfer station  33 . The pulleys  12  and  15  form part of a transfer device  34  comprising a carriage which is schematically illustrated as a block  35  supporting the two pulleys  12  and  15 .  
         [0021]    As shown in FIGS.  4  to  9 , the carriage  35  also supports two pairs of pulleys  36 ,  37  and  38 ,  39  mounted on respective shafts  36   a ,  37   a  and  38   a ,  39   a  positioned perpendicularly to the feed direction  20  and to the shafts of the pulleys  12  and  15 . The pulleys  12  and  15  may be kinematically and respectively connected to the shafts  36   a ,  37   a  and  38   a ,  39   a  in known manner (as described in the Italian ACMA patent No. 1285693, incorporated herein by reference) or they may be equipped with a separate motor, labeled M 3 .  
         [0022]    As shown in FIGS. 4, 5,  7  and  9 , the pulley pairs  36 ,  37  and  38 ,  39  respectively support belts  40  and  41 , each having respective straight portions  42  and  43 , which are parallel to each other and located on opposite sides of the feed path P. Consequently, the straight portions  42  and  43  extend between the conveyor portions  29  and  32  close to the pulleys  12  and  15 .  
         [0023]    As shown in FIGS. 2 and 3, the pulleys  14  and  18  are mounted on a second carriage  44  which connects to each other the two first ends of two segments  45  and  46  of a drive belt  47  looped around two pulleys  48  and  49  and, at the other two ends of its segments  45  and  46 , being connected to the ends of the first carriage  35 . The pulley  48  is a drive pulley and is connected to a motor M 4 , while the pulley  49  is an idle, driven pulley.  
         [0024]    The motor M 4  drives the drive belt  47  in such a way as to move the carriage  35  along the feed path P in the direction  20  or in the opposite direction, labeled  50 , so as to complementarily vary the length of the conveyor portions  29  and  32  to which there corresponds an equal and opposite movement of the second carriage  44  in a direction parallel to the path P. As shown in FIGS. 1, 2 and  3 , the feed device  8  forms part of a bar soap  2  plodder schematically illustrated as a block  51 , and consists of a plurality of pickup and transfer elements  52  having on the ends of them respective suction cups  53  that move up and down on pistons  54 . Through said pickup and transfer elements  52 , the feed device  8  cyclically transfers the products  2  from the machine  51  to the pockets  23  on the first conveyor  6 .  
         [0025]    In the embodiment illustrated, the feed device  8  consists of two groups of pickup and transfer elements  52  capable of transferring sets  5  consisting of two groups of four products  2  each, with a space p 1  between each one and the next, from the machine  51  to the first conveyor  6 .  
         [0026]    According to the invention, the first conveyor  6  also moves cyclically according to a law of motion and timing dependent upon the cyclic motion of the feed device  8 . In particular, as shown in FIGS. 1, 2 and  3 , the first conveyor  6  follows a law of intermittent motion that is defined by a step of pausing, illustrated in FIGS. 1, 2,  4  and  5 , during which the device  8  transfers and places in the pockets  23  a set  5  of products  2 , and a step of feeding the products  2  towards the second conveyor  7  which moves continuously (FIGS. 3, 6,  7 ,  8  and  9 ).  
         [0027]    The products  2  are transferred from the first conveyor  6  to the second conveyor  7  by the transfer device  34  which also moves cyclically, with reciprocating motion, between a first end position, labeled A where it is close to the feed device  8 , and a second end position, labeled B, where it is away from the feed device  8 , in such a way as to complementarily vary the lengths of the conveyor portions  29  and  32  of the first and second conveyors  6  and  7 , respectively.  
         [0028]    The belts  40  and  41  move cyclically, with intermittent motion, and more specifically, perform a first transfer step in which the branches  42  and  43  move in the direction  20  during the passage of the transfer device  34  from the end position B to the end position A in the direction  50 , as illustrated in FIGS. 6, 7,  8  and  9 , synchronized with the feeding step of the first conveyor  6 , and a second transfer step, illustrated in FIGS. 4 and 5, in which the branches  42  and  43  stop and the device  34  moves in the direction  20  carrying with it at least one product  2  placed between the branches  42  and  43  of the belts  40  and  41 , which are made of a resilient material of uniform thickness to improve their grip on and adherence to the products  2  themselves. This second step is synchronized with the step of pausing the first conveyor  6 .  
         [0029]    It should be stressed that during this step, when the first conveyor  6  is pausing, the driving of the device  34 , and thus of the first carriage  35 , in the direction  20  by the drive belt  47  enables the return branch  28  of the belt  9  of the first conveyor  6  to be unwound from the end pulley  12  along the path P and enables the forward branch  30  of the belt  10  of the second conveyor  7 , moving continuously, to be wound around the pulley  15 . More specifically, after the pausing step of the first conveyor  6  to allow reception of the sets  5  and during which the carriage  35  proceeds along the path P in the direction  20  from position A to position B, the first conveyor  6  accelerates in such a way that the first product  2  in the set  5  can reach the last product  2  in the set  5  placed in the preceding cycle. This acceleration step is followed by a step of feeding the first conveyor  6  at a substantially constant speed equal to the speed of the second conveyor  7 . More specifically, accelerating the first conveyor  6  makes it possible, in a case such as that described above and illustrated where the groups of four products  2  for each set  5  are separated by a space p 1 , to eliminate the space p 1 .  
         [0030]    Lastly, the numeral  55  denotes a control unit connected to the motors M 1 , M 2 , M 4  and, if fitted, also to the motors M 3  of the transfer device  34 . The control unit  55  is controlled from a panel  56  which can be used to enter the data describing the structural and functional characteristics and the related laws of cyclic motion of the first and second conveyors  6  and  7  and of the transfer device  34  in relation to the law of cyclic motion of the feed device  8 .