Patent Publication Number: US-11040511-B2

Title: Folding apparatus for folding sheet packaging elements

Description:
This is a National Phase of PCT Application No. PCT/EP2016/054067, filed Feb. 26, 2016, which claims the benefit of European Application No. 15157205.4 filed Mar. 2, 2015, both of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present invention relates to a folding apparatus for folding sheet packaging elements, in particular cardboard blanks designed to be transformed into packaging boxes housing multiple packages or containers and adapted to be delivered to sales outlets. 
     The present invention may be advantageously but not exclusively used in plants for packaging pourable food products, such as beverages, milk, wine, tomato sauce, etc., in sealed packages, containers or the like, which are then packed in groups into the above-mentioned packaging boxes. 
     The present description refers to this specific field, although this is in no way intended to limit the scope of protection as defined by the accompanying claims. 
     BACKGROUND OF INVENTION 
     As known, the said sealed packages or containers are formed, filled and closed in a machine or a combination of machines and are then conveyed to an end packaging station, in which the sealed packages or containers are packaged in groups into packaging boxes. 
     Conveniently, packaging boxes are formed from respective sheet packaging elements, which are stored in a magazine and picked up from the latter to be then subjected to folding operations in the end packaging station. 
     Packaging elements are typically defined by plane, rectangular or square blanks, which, in some cases, may also be provided with handles to ease transportation of the resulting packaging boxes. Each handle is in general applied to one of the opposite faces of a relative packaging element so as to protrude from the latter. 
     Each packaging element is first folded to achieve a U-shaped configuration with a horizontal base portion and two vertical facing portions, extending orthogonally from opposite end edges of the base portion. One of the facing portions may be conveniently higher than the other so as to be then folded towards the latter; in practice, the protruding end of the higher facing portion is made horizontal so as to define a cover portion parallel to the base portion and connected to the other facing portion to define a quadrangular box. 
     The group of packages or containers is housed in use within the so formed box; in particular, the packages or containers rest on the base portion, are surrounded by the facing portions and are covered on top by the cover portion. 
     All portions of the so formed packaging box are provided with lateral flaps that are then folded to become vertical in order to block laterally the packages or containers housed within the packaging box itself. 
     A need particularly felt within the industry is to perform the above-described operations, and especially the ones for producing the U-shaped configuration of the packaging elements, at high speed and possibly in a continuous manner. 
     Another need particularly felt within the industry is to obtain the U-shaped configuration of each packaging element without using the packages or containers as a reference for the folding operations in such a way that these latter operations are not affected by the weight or format of the packages or containers destined to be housed in the final packaging box. 
     A further need particularly felt within the industry is to perform the above-described folding operations, and especially the ones for producing the U-shaped configuration of the packaging elements, irrespective of the sizes, material and thickness of the packaging elements to be folded. 
     DISCLOSURE OF INVENTION 
     It is therefore an object of the present invention to provide a folding apparatus for folding sheet packaging elements, which allows satisfying at least one of the aforementioned needs. 
     According to the present invention, there is provided a folding apparatus for folding sheet packaging elements, as claimed in claim  1 . 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A preferred, non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which: 
         FIG. 1  shows a perspective view of a folding apparatus according to the present invention for folding sheet packaging elements, with parts removed for clarity; 
         FIG. 2  shows a larger-scale perspective view of a packaging element in the condition in which it is fed to the apparatus of  FIG. 1 ; 
         FIG. 3  shows a perspective view of the packaging element of  FIG. 2  in the condition in which it is released by the apparatus of  FIG. 1 ; 
         FIG. 4  shows a larger-scale side view of the apparatus of  FIG. 1 , with parts removed for clarity; and 
         FIGS. 5 to 9  show larger-scale side views of a portion of the apparatus of  FIG. 4 , in different operative conditions and with parts removed for clarity. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Number  1  in  FIGS. 1 and 4  indicates as a whole a folding apparatus for folding sheet packaging elements  2 , in particular cardboard blanks designed to be transformed into packaging boxes (known per se and not shown) housing multiple packages or containers (known per se and not shown). 
     As shown in detail in  FIGS. 2 and 4 to 9 , each packaging element  2  is fed to folding apparatus  1  in a vertical configuration, in which it extends along a vertical plane and presents a substantially rectangular profile. In particular, in its vertical configuration, each packaging element  2  is delimited by two opposite longitudinal sides  3   a ,  3   b  (see in particular  FIG. 2 ) and by two opposite transversal sides  4   a ,  4   b , each one joining corresponding ends of longitudinal sides  3   a ,  3   b . More specifically, in the vertical configuration, transversal side  4   a  is arranged at an upper position than transversal side  4   b.    
     Each packaging element  2  is also provided with a plurality of lateral flaps  5  protruding from sides  3   a ,  3   b  and  4   b  and destined to be folded towards these latter sides to form the final packaging box. 
     Each packaging element  2  is also provided with three pairs of lateral cuts or recesses  6 , which are formed on opposite sides  3   a ,  3   b.    
     Each packaging element  2  may further comprise two or more transversal crease lines, in the present case three transversal crease lines referenced as  7   a ,  7   b ,  7   c , along which the packaging element  2  is destined to be folded to form the final packaging box. 
     Transversal crease lines  7   a ,  7   b ,  7   c  extend parallel to sides  4   a ,  4   b  and at different distances therefrom; in particular, crease line  7   a  is adjacent to side  4   a , crease line  7   b  is adjacent to side  4   b  and crease line  7   c  is located at an intermediate position between crease lines  7   a  and  7   b.    
     Folding apparatus  1  is in particular adapted to fold each packaging element  2  along crease lines  7   b ,  7   c  to define a sort of U-shaped configuration (see in particular  FIGS. 1, 3 and 9 ), with an intermediate horizontal portion  8  delimited by the crease lines  7   b ,  7   c  themselves and two opposite vertical facing portions  9 ,  10  extending orthogonally from intermediate portion  8  and having different heights therefrom ( FIGS. 1 and 3 ). In the present case, portion  9 , delimited by transverse side  4   a , is taller than portion  10  in the U-shaped configuration. 
     In the vertical configuration of each packaging element  2 , portion  9  is located at an upper position than portion  8 , which is in turn at an upper position than portion  10 . 
     According to a possible alternative not shown, folding apparatus  1  may also produce the U-shaped configuration without providing any crease line on the relative packaging element  2 . 
     With reference to  FIGS. 1 and 4 to 9 , folding apparatus  1  comprises:
         a support structure  11 ;   a main conveying unit  12  mounted on support structure  11  and configured to sequentially receive packaging elements  2  from a feeding station  13  and to continuously advance each packaging element  2  along a given path A, in the example shown defined by a horizontal direction;   forming means  15  carried by main conveying unit  12  and configured to cooperate in use with a first face  2   a  of each packaging element  2  while the latter is advanced along path A;   an auxiliary conveying unit  16  mounted on support structure  11  in a position partially facing main conveying unit  12 ; and   folding means  18  advanced continuously by auxiliary conveying unit  16  along an endless path Q, having a first portion Q 1 , distinct from path A, and a second portion Q 2 , which is in common, or aligned, with path A itself and along which the folding means  18  cooperate with a second face  2   b , opposite face  2   a , of each packaging element  2  to fold the latter against forming means  15 .       

     With reference to  FIGS. 1 and 4 , support structure  11  basically comprises a horizontal base frame  20  and a tower frame  21 , which protrudes upwards from a head portion  22  of base frame  20  and defines an inlet section  23  of folding apparatus  1 . 
     In particular, base frame  20  rests on the floor through a plurality of height-adjustable feet  24  and comprises two longitudinal supporting beams  25  and a plurality of transverse supporting beams  26 , three in the example shown. In particular, longitudinal supporting beams  25  extend parallel to path A, whilst transverse supporting beams  26  extend orthogonally to path A and to the longitudinal supporting beams  25 . 
     Tower frame  21  comprises four struts  27 , vertically extending upwards in pairs from respective head portions of longitudinal supporting beams  25 ; struts  27  are connected in pairs, in proximity of their tops, by respective transverse bars  28  parallel to transverse supporting beams  26 ; struts  27  are also connected in pairs, in proximity of their tops, by respective side rails  30  extending parallel to longitudinal supporting beams  25 . 
     Support structure  11  further comprises a horizontal intermediate frame  31  arranged above and at a distance from base frame  20  and supported by struts  27  of tower frame  21  and by end struts  32 , extending vertically upwards from respective longitudinal supporting beams  25  at an outlet section  33  of folding apparatus  1  and having smaller heights than those of struts  27 . Intermediate frame  31  has a structure similar to that of base frame  20  and is not further described. 
     Main conveying unit  12  is supported by base frame  20  and intermediate frame  31  as well as by bottom portions of struts  27  and by end struts  32 ; main conveying unit  12  is located, for the most part, in the space delimited by base frame  20  intermediate frame  31 , struts  27  and end struts  32 . 
     Auxiliary conveying unit  16  is instead entirely supported by tower frame  21  and is arranged, for the most part, in the space delimited by the struts  27 . 
     Feeding station  13  comprises a pair of lateral retainers  35  ( FIGS. 5 to 9 ) carried by struts  27  of tower frame  21  at inlet section  23  and adapted to temporarily stop packaging elements  2  arriving in their vertical configurations from an upstream processing apparatus or from an upstream magazine (not shown). 
     In particular, at feeding station  13 , packaging elements  2  are accumulated against each other and against lateral retainers  35  so as to be compacted into a batch  36  of adjacent packaging elements  2 . More specifically, at feeding station  13 , packaging elements  2  are supported in their vertical configurations by lateral horizontal flaps (known per se and not shown) engaging respective opposite and aligned recesses  6 . 
     As visible in particular in  FIGS. 1 and 4 , main conveying unit  12  comprises a linear horizontal transport branch  40 , defining path A and along which forming means  15  and packaging elements  2  are conveyed towards outlet section  33 . In particular, during transfer from feeding station  13  to main conveying unit  12 , each packaging element  2  passes from the vertical configuration to a configuration in which it lies, at least partially, with its face  2   a  on transport branch  40 . The way in which packaging elements  2  are transferred from feeding station  13  to main conveying unit  12  will be explained in detail later on. 
     Auxiliary conveying unit  16  is arranged between feeding station  13  and main conveying unit  12  as well as at an upper position than that of main conveying unit  12 . 
     With reference to  FIGS. 1, and 4 to 9 , forming means  15  comprise a plurality of first forming elements  41  adapted to cooperate with crease lines  7   b  of packaging elements  2 , and a plurality of second forming elements  42  alternate to first forming elements  41  and adapted to cooperate with crease lines  7   c  of packaging elements  2 . 
     In practice, during advancement along path A, each packaging element  2  is arranged between one first forming element  41  and one second forming element  42 ; more specifically, the first forming element  41  is arranged on the back of the packaging element  2  and pushes it along path A, whilst the second forming element  42  is placed in front of the packaging element  2  itself. 
     Main conveying unit  12  comprises a first conveying device  43 , carrying first forming elements  41 , and a second conveying device  44 , carrying second forming elements  42 ; conveying devices  43 ,  44  have respective operative branches  43   a ,  44   a  parallel to one another, defining transport branch  40  and lying on a common horizontal plane. 
     In particular, conveying device  43  comprises two parallel conveyors  45 , to which first forming elements  41  are rigidly secured and which define an endless path P for the first forming elements  41  themselves. 
     In the example shown, conveyors  45  comprise respective parallel endless chains  46  passing round a plurality of pairs of interconnected toothed wheels  48 , four pairs in the example shown. One pair of toothed wheels  48  is motorized to impart motion to respective chains  46 . 
     First forming elements  41  are secured to respective chains  46  and are uniformly distributed along the chains  46  themselves. 
     In particular, each first forming element  41  projects from the respective chain  46  and has a shape resembling a set square, with a profile of a right-angled triangle. In particular, each first forming element  41  is delimited by a base surface  49  attached to the respective chain  46 , a forming surface  50  orthogonal to chain  46  as well as to base surface  49  and adapted to cooperate in use with a relative packaging element  2 , and a slanted surface  51  connecting base surface  49  and forming surfaces  50 . Forming surface  50  of each first forming element  41  extends orthogonally to the transport branch  40  of main conveying unit  12  when such first forming element  41  is advanced along path A. 
     Each chain  46  preferably lies on a substantially vertical plane and has a profile shaped like an isosceles trapezium. 
     Each chain  46  comprises:
         a horizontal transport portion  52  parallel to path A and defining, together with transport portion  52  of the other chain  46 , operative branch  43   a;      a horizontal return portion  53 , which is parallel to transport portion  52 , is shorter than transport portion  52  and is arranged beneath transport portion  52 ; and   slanted connection portions  54 ,  55 , which connect respective end portions of transport portion  52  to corresponding end portions of return portion  53 .       

     In particular, connection portion  54  is adjacent to inlet section  23  of folding apparatus  1 , whilst connection portion  55  is adjacent to outlet section  33  of the folding apparatus  1  itself. 
     As visible in  FIG. 1 , conveying device  44  is arranged between conveyors  45  and has a structure very similar to that of conveying device  43 . 
     In particular, even in this case, conveying device  44  comprises two parallel conveyors  56 , to which second forming elements  42  are rigidly secured and which define an endless path R—for the most part parallel to path P—for the second forming elements  42  themselves. 
     In the example shown, conveyors  56  comprise respective parallel endless chains  57  passing round a plurality of pairs of interconnected toothed wheels  58 , four pairs in this case. One pair of toothed wheels  58  is motorized to impart motion to respective chains  57 . 
     Chains  57  are internally adjacent to respective chains  46  and define therebetween a gap  47 , whose function will be clarified later on. 
     Second forming elements  42  are secured to respective chains  57  and are uniformly distributed along the chains  57  themselves. 
     In particular, each second forming element  42  projects from the respective chain  57  and has a shape resembling a set square, with a profile of a right-angled triangle. In particular, each second forming element  42  is delimited by a base surface  59  attached to the respective chain  57 , a forming surface  60  orthogonal to chain  57  as well as to base surface  59  and adapted to cooperate in use with a relative packaging element  2 , and a slanted surface  61  connecting base surface  59  and forming surface  60 . 
     Forming surface  60  of each second forming element  42  extends orthogonally to the transport branch  40  of main conveying unit  12  when such second forming element  42  is advanced along path A. Forming surface  60  of each second forming element  42  faces forming surface  50  of the first forming element  41  cooperating in use with the same packaging element  2  and define, with the portion of the transport branch  40  comprised therebetween, a U-shaped profile forming a seat  62 , within which the packaging element  2  itself is correspondingly folded by interaction with folding means  18 . 
     Even in this case, each chain  57  preferably lies on a substantially vertical plane and has a profile shaped like a trapezium. 
     Each chain  57  comprises:
         a horizontal transport portion  63  coplanar with path A and transport portion  52  of chains  46  and defining, together with transport portion  63  of the other chain  57 , operative branch  44   a;      a horizontal return portion  64 , which is parallel to transport portion  63 , is shorter than transport portion  63  and is arranged beneath the latter; and   slanted connection portions  65 ,  66 , which connect respective end portions of the transport portion  63  to corresponding end portions of the return portion  64 .       

     In particular, connection portion  65  is adjacent to inlet section  23  of folding apparatus  1 , whilst connection portion  66  is adjacent to outlet section  33  of the folding apparatus  1  itself. 
     As clearly shown in  FIGS. 1 and 4 , chains  57  are parallel to chains  46  except at connection portions  55 ,  66  adjacent to outlet section  33 ; as a matter of fact, transport portions  52  of chains  46  are longer than transport portions  63  of chains  57  at outlet section  33  to allow a completion of the pushing action on packaging elements  2  by first forming elements  41  at the exit of folding apparatus  1 . 
     With reference to  FIGS. 1 and 4 to 9 , folding means  18  are carried by auxiliary conveying unit  16  and comprise a plurality of first folding bars  71  adapted to fold packaging elements  2  along crease lines  7   c  and against respective second forming elements  42 , and a plurality of second folding bars  72  alternate to folding bars  71  and adapted to fold packaging elements  2  along crease lines  7   b  and against respective first forming elements  41 . 
     In a manner analogous to main conveying unit  12 , auxiliary conveying unit  16  comprises a first conveying device  73 , carrying first folding bars  71 , and a second conveying device  74 , carrying second folding bars  72 ; first conveying device  73  and second conveying device  74  have respective folding branches  73   a ,  74   a  parallel to one another and lying, with operative branches  43   a ,  44   a  of main conveying unit  12 , on a common horizontal plane. 
     In particular, first conveying device  73  comprises two parallel conveyors  75 , to which first folding bars  71  are rigidly secured. 
     In the example shown, conveyors  75  comprise respective parallel endless chains  76  passing round a plurality of pairs of interconnected toothed wheels  78 . One pair of toothed wheels  78  is motorized to impart motion to respective chains  76 . 
     First folding bars  71  extend transversally to chains  76  and interconnect them; more specifically, first folding bars  71  are secured at their opposite ends to respective chains  76  and are uniformly distributed along the chains  76  themselves. 
     Each chain  76  preferably lies on a substantially vertical plane and comprises, by proceeding along path Q:
         a horizontal folding portion  82  extending in use within the gap  47  between chains  57  and coplanar with transport portions  52 ,  63  of chains  46 ,  57  as well as with the folding portion  82  of the other chain  76 ;   an ascending ramp-shaped portion  83 , slantingly extending upwards from folding portion  82 ;   a return portion  84  facing folding portion  82 ;   a vertical transfer portion  85  facing feeding station  13  and extending, in use, parallel to the packaging elements  2  forming the batch  36  at the feeding station  13  itself; and   a descending ramp-shaped portion  86  connecting transfer portion  85  to folding portion  82 .       

     As visible in  FIG. 1 , second conveying device  74  is arranged between conveyors  75  and has a structure very similar to that of first conveying device  73 . 
     In particular, even in this case, second conveying device  74  comprises two parallel conveyors  87 , to which second folding bars  72  are rigidly secured. 
     In the example shown, conveyors  87  comprise respective parallel endless chains  88  passing round a plurality of pairs of interconnected toothed wheels  89 . One pair of toothed wheels  89  is motorized to impart motion to respective chains  88 . 
     Chains  88  are internally adjacent to respective chains  76  and are interconnected by second folding bars  72 ; more specifically, second folding bars  72  are secured at their opposite ends to respective chains  88  and are uniformly distributed along the chains  88  themselves. 
     Chains  88  exactly have the same configurations as chains  76 ; therefore, the component parts of chains  88  will be indicated in the following description and drawings with the same references as those used for chains  76 . 
     Ramp-shaped portions  83 ,  86 , return portions  84  and transfer portions  85  of chains  76 ,  88  define portion Q 1  of path Q, distinct from path A; folding portions  82  of chains  76 ,  88  define portion Q 2  of path Q, in common with path A. 
     Transfer portions  85  of chains  76 ,  88  advantageously define an operative part Q 1 A of portion Q 1  of path Q, along which folding bars  71 ,  72  interact in use with each packaging element  2  to transfer it from feeding station  13  to main conveying unit  12 . 
     In particular, folding apparatus  1  further comprises a suction head  90  for separating one end packaging element  2  from the rest of the batch  36  so as to allow insertion of first folding bars  71  and second folding bars  72  between the separated end packaging element  2  and the batch  36 . 
     In practice, suction head  90  is only used to separate the end packaging element  2  from the rest of the batch  36 , whilst the first folding bars  71  and the second folding bars  72 , moving along part Q 1 A of path Q, act on the separated end packaging element  2  to transfer it from feeding station  13  to main conveying unit  12 . 
     Suction head  90  is suspended, through an articulated parallelogram  91 , to tower frame  21  in a position facing feeding station  13  and is movable towards and away from the batch  36  between a rest position ( FIG. 9 ), in which the suction head  90  is separated from the batch  36 , and an operative position ( FIG. 5 ), in which the suction head  90  is adjacent to the batch  36  to pick up the end packaging element  2  thereof. 
     In particular, in the rest position, suction head  90  faces portion  9  of the packaging element  2  to be separated from the rest of the batch  36 ; in the operative position, suction head  90  contacts portion  9  of the packaging element  2  to be separated from the batch  36  and suction is active. 
     Suction head  90  moves substantially parallel to path A; in this way, during its movement from the operative position to the rest position, suction head  90  separates the end packaging element  2  from the batch  36  by disengaging such packaging element  2  from the flaps on which it is suspended and by inclining it forward, towards main conveying unit  12 . 
     During this step, the separated packaging element  2  rests with its flap  5  of side  4   b  on a fixed bottom plate  92  carried by support structure  11 . 
     Suction head  90  is advantageously moved between a pair of stop rails  93  adapted to define an abutment for the portion  9  of the separated packaging element  2 . 
     By considering the movement of forward inclination of the separated packaging element  2  towards main conveying unit  12 , stop rails  93  are arranged between the rest and operative position of suction head  90 , so as to allow disengagement of the suction head  90  from the packaging element  2  prior to reaching the rest position. 
     As visible in  FIGS. 5 and 7 , part Q 1 A of path Q advantageously extends between the rest position and the operative position of suction head  90 , so as to allow interaction of first folding bars  71  and second folding bars  72  with the separated packaging elements  2  to transfer the latter to main conveying unit  12 . In addition, part Q 1 A of path Q extends between the rest position of suction head  90  and stop rails  93 ; in this way, the separated packaging element  2  extends transversally to part Q 1 A of path Q and can be intercepted by first folding bars  71  and second folding bars  72 . 
     Operation of folding apparatus  1  will be described with reference to the folding of one packaging element  2  and as of an initial condition ( FIG. 5 ), in which:
         such packaging element  2  is in its vertical configuration against lateral retainers  35  and cooperates with suction head  90  is in its operative position;   the first folding bar  71  and second folding bar  72  destined to cooperate with said packaging element  2  are moving along operative part Q 1 A of path Q towards feeding station  13 ; and   the first forming element  41  and the second forming element  42 , also destined to interact with the mentioned packaging element  2 , are moving along portions  53 ,  64  of respective chains  46 ,  57 .       

     Suction head  90  is moved towards its rest position and retains, by suction, portion  9  of the packaging element  9 , which therefore moves together with the suction head  90  itself and separates from the batch  36 . During this movement, the packaging element  2  disengages from the flaps on which it is suspended and, thanks to its deformability, also disengages from lateral retainers  35 . In practice, the packaging element  2  leans forward, towards main conveying unit  12 , and rests with its flap  5  of side  4   b  on bottom plate  92  ( FIG. 7 ). 
     The movement of the packaging element  2  ends against stop rails  93 , at which suction head  90  separates from the packaging element  2  and reaches its rest position ( FIG. 7 ). In this condition, the packaging element  2  extends obliquely with respect to part Q 1 A of path Q and transversally to portions  85  and  86  of chains  76 ,  88 ; in this way, the packaging element  2  can be intercepted firstly by the first folding bar  71  and then by the second folding bar  72 . 
     As shown in  FIG. 8 , the first folding bar  71 , by moving along portions  85  and  86  of chains  76 , bends portions  9  and  8  of the packaging element  2  onto transport branch  40  of main conveying unit  12 . 
     In the meantime, the second forming element  42  destined to cooperate with crease line  7   c  of the packaging element  2  precede the packaging element  2  and the first folding bar  71  along path A; in this way, during advancement along portion Q 2  of path Q, the first folding bar  71  folds the packaging element  2  along crease line  7   c  and against forming surfaces  60  of the second forming elements  42 ; at the end of this step, the portion  9  of the packaging element  2  extends orthogonally to the portion  8  and is advanced along path A in abutment against forming surfaces  60  of the second forming elements  42 . 
     The first folding bar  71  comprises, at opposite ends thereof, protruding elements  100  that folds downwards the lateral flaps  5   a  interposed between the transversal crease lines  7   b  and  7   c . In this way, the lateral flaps  5   a  do not interfere with the packages when the packages are inserted into the folded packaging element  2  in a direction perpendicular to path A. 
     Along the subsequent portions  83  of chains  76 , the first folding bar  71  releases the packaging element  2 . 
     In the meantime, first forming element  41  intercepts the portion  10  of the packaging element  2  while the second folding bar  72 , moving along portions  86  of chains  88 , precedes the first forming element  41  along path A. 
     Along portions  82  of chains  88  and along portions  52  of chains  46  in common with the portions  82 , the first forming elements  41  and the first folding bar  72  cooperate with the respective opposite faces  2   b ,  2   a  of the packaging element  2  to fold it along crease line  7   b  ( FIG. 9 ). 
     At the end of this step, the packaging element  2  is therefore folded in the U-shaped configuration, in which it is housed within seat  62 , delimited by the second forming elements  42  on the front side, with respect to path A, and by the first forming elements  41  on the back side. 
     Along the portions  83  of chains  88 , even the folding bar  72  releases the packaging element  2 , which is therefore advanced towards outlet section  33  by the first forming elements  41  and the second forming elements  42 . 
     In particular, in the proximity of outlet section  33 , the second forming elements  42  move away from the packaging element  2  by deviating along connection portions  66  of chains  57 ; the packaging element  2  is therefore pushed to outlet section  33  by first forming elements  41  only, prosecuting along the end part of transport portions  52  of chains  46 . 
     The advantages of folding apparatus  1  according to the present invention will be clear from the foregoing description. 
     In particular, the described solution, with folding means  18  acting continuously on the packaging elements  2  to fold them against forming means  15  while being advanced along path A, allows to reach very high processing speeds as well as an improved reliability with respect to known solutions. 
     In addition, by folding the packaging elements  2  onto continuously-moving mechanical reference elements defined by forming means  15 , instead of onto the packages or containers to be housed in the final packaging boxes, makes this operation independent from the weight or format of such packages or containers as well as from the material and/or format and/or thickness of the packaging elements  2 . 
     In addition, the use of suction is limited to separate the packaging element  2  to be folded from the blank  36 , while the transfer of such packaging element  2  to main conveying unit  12  is performed by the same folding means  18  used for folding the packaging elements  2 . This also contributes to increase the processing speed, as it is not necessary to wait for the suction head  90  to perform the entire transfer. 
     Furthermore, the structures of conveying devices  43 ,  44 ,  73  and  74  allow to easily vary the spacing between adjacent first forming elements  41  and second forming elements  42  as well as between first folding bars  71  and second forming bars  72  to adapt to different formats of packaging elements  2  to be folded or different distances between the crease lines of such packaging elements  2 . 
     Clearly, changes may be made to folding apparatus  1  as described herein without, however, departing from the scope of protection as defined in the accompanying claims. 
     In particular, chains  46 ,  57 ,  76 ,  88  may be replaced by other types of endless transport elements, such as belts. 
     In addition, each pair of folding bars  71 ,  72  may be replaced by one folding plate, whose front and rear edges perform the same functions as the replaced folding bars  71 ,  72 .