Patent Document

FIELD OF THE INVENTION 
     Tubular blanks are known, in a flattened configuration, from which corresponding containers (for example boxes) are obtained. 
     To obtain these containers it is necessary to operate on the blanks with the aim of changing the configuration thereof, from flat to tubular, i.e. it is necessary to open out the blank. 
     The above function is performed by various apparatus. 
     DESCRIPTION OF THE PRIOR ART 
     A known type of apparatus consists of means acting to collect a bottom blank of a stack of blanks in a flattened tubular configuration, contained in a store, for transfer to a station of a series of stations located along a periphery of a drum set in constant rotation; these stations are identical and are angularly equidistanced. 
     Each of the stations is provided with retaining means that engage a first of two external flaps of each blank, and folding means acting on the remaining flap of the two external flaps in order to fold the remaining flap by at least ninety degrees with respect to the first (actually by more than 90° in order to compensate for the elastic return of the blank). 
     The blank, in open tubular configuration, is transferred onto a supply line, such as a type having compartments, of a packing machine which forms the bottom of the corresponding container, inserts predetermined articles via the open end of the container and lastly closes the open end by folding tabs hinged to the flaps of the blank. 
     This transfer (see FR 2,478,576) is implemented by an operating station constituted by a chain conveyor consisting of two equal and opposite chains, winding about two crown wheels, one a drive crown and the other a driven crown. These chains are connected to transversal support and guide rods for the corresponding sleds. 
     Each sled bears a transversal arm provided with suckers. 
     The sleds are subjected to the action of cams conformed such as to move the sleds transversally in suitable phase relation with the movement of the chains. 
     The positioning of the suckers, borne by the relative transversal arm, is such as to define two end positions. 
     In a first end position, which occurs when the arm is moving along the curved portion of the transporter (arranged in front of the above-mentioned drum), the suckers intercept a flap of the open tube, situated in a station of the drum; the activation of the suckers in phase relation with the deactivation of the retaining suckers of the station, cause the blank to transfer to the suckers of the arm. 
     Thereafter, the arm describes a portion of circular trajectory and is then subjected to a longitudinal motion, with a velocity that is equal to that of the above-mentioned compartmented line, and to a horizontal motion towards the compartments such as to introduce the opened-out blank into a compartment (second end position of the suckers of the arm). 
     At this point, the suckers are deactivated and the arm translates transversally in the opposite direction to the previous one. 
     Abutting means are provided for maintaining the blank opened out up to when it is introduced into the relative compartment. 
     A drawback of the aforementioned operating station is connected with the fact that it is necessary to move the drum, in suitable phase relationship, for opening the blank out, as well as the chains that carry the blanks and the line bearing the crates. 
     Further drawbacks derive from the complexity of the work station, in particular the conformation of the cams operating the sleds, due to the fact that the sleds projectingly support the arms and also due to the fact that fixed abutments are comprised in order to keep the blanks opened out. This problem is exacerbated when the format has to be changed. 
     The work station is arranged flanked to the supply line and develops mostly at a lower height than the line: this leads to a corresponding large overall transversal size of the whole apparatus (i.e. rotating drum and work station) and of the packing machine. 
     The main aim of the present invention is to obviate the above drawback, and in particular to disclose a system implementing the transfer of blanks in an open tubular configuration directly from the drum to the supply line of a packing machine. 
     A further aim of the invention is to provide a system which enables intervening on the drum, and on the supply means thereto of the tubular blanks in the flattened configuration, such as to streamline and simplify the change-format operation of the blanks. 
     SUMMARY OF THE INVENTION 
     The main aim is attained in accordance with the present invention is achieved by a system for transferring tubular blanks in an open configuration to a supply line of a packing machine, the line being constituted by belts loop-wound on at least two crown wheels, a drive wheel and a driven wheel, to which belts an abutting segment and a thrust segment are perpendicularly fixed, alternatively from downstream to upstream, facing externally so as to define at an upper branch of the line, at which the abutting segment and the thrust segment are vertical, equidistanced compartments, the segments identifying, in a curved tract located upstream of the upper branch, in which the segments are radial with respect to an axis of the relative crown of the crowns, dynamic seatings a dimension of which in a motion direction of the line is greater than a dimension thereof of a corresponding compartment. The system comprises an apparatus destined to position a tubular blank in an open configuration intermittently in a zone situated in front of the head of the line defining the curved tract, the tubular blank being hooked to relative retaining means; a rotating member, activated in phase relation with a movement of the belts, arranged between the longitudinal walls of the line at the head, coaxial with the crown relative thereto, and provided with a series of transfer means which are angularly equidistanced along a circumference tangential to the upper branch, the transfer means involving, in the tract facing towards the head, a corresponding dynamic seating for encountering, in the zone, a flap of the tubular blank, the tubular blank being freely inserted in the dynamic seating, and subsequently hooking it consequently of the activation of the transfer means actuated in phase relation with a deactivation of the retaining means, the transfer means being deactivated in proximity of the upper branch in phase relation with the arranging from radial to vertical of the abutting segment and the thrust segment first delimiting the dynamic seating and finally the compartment corresponding to the dynamic seating, which by means of the segments retains the tubular blank and establishes the open tubular conformation thereof. 
     The apparatus is preferably defined by: a store containing a stack of tubular blanks destined to hook the first flap of the two external flaps of the base blank of the stack; a drum rotating with respect to an axis that is parallel to the rotation axis of the rotating member, peripherally exhibiting angularly-equidistanced work stations transiting intermittently in the zone, each of the stations being provided with retaining means destined to receive, from the pick-up means, upstream of the zone, the first flap of the blank picked up from the base of the stack and to hook the first flap following activation of the retaining means actuated in phase relation with a deactivation of the pick-up means, each of the work stations being provided with folding means rotating in an opposite direction to the rotation direction of the drum in order to intercept the second flap of the two external flaps with a consequent rotation of the flap about the score-line connecting the two external flaps to define the open tubular configuration of the blank. 
     The transfer of the tubular blank in an open configuration from the drum to the upper supply branch of the supply line of the packing machine will be actuated by means of the rotating member which is coaxial to the head of the line facing towards the drum and positioned internally of the longitudinal walls of the line; this technical-functional aspect simplifies the phase relation between the work stations of the drum and the line, and also does not involve occupying additional space as the rotating member does not exceed the dimensions of the line. 
     Abutting means are not required to prevent the flattening of the blank during transfer thereof into the crates of the line. 
     A further advantage is achieved where the apparatus is supported by a structure which can translate in a direction defined by the line joining the axes respectively of the drum and the rotating member, enabling transit into the zone of the work stations on varying a format of the tubular blanks. 
     On varying the format, it is sufficient to translate the structure bearing the apparatus: this enables non-intervention on the two reference planes of the system of the invention, of which one relates to the “opening-out” of the blank and the other to the supply line. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further characteristics of the invention will emerge from the following description, which makes reference to the accompanying figures of the drawings, in which; 
         FIG. 1  is a view from above of the system of the invention; 
         FIGS. 2A ,  2 B are perspective views from different angles, of the system of  FIG. 1 ; 
         FIGS. 3A ,  3 B are front views of the system of the invention, respectively relating to two different blank formats; 
         FIG. 4  illustrates, in enlarged scale, the detail J of  FIG. 3B , with parts removed and others (not shown in  FIG. 3B ) highlighted such as to focus on technical and functional aspects; 
         FIG. 5  illustrates, in enlarged scale, zone Z of  FIG. 3A . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     It is known that a tubular blank  150  is constituted by four consecutive flaps connected by score-lines  1 A- 1 D  2 A- 2 D, which behave as hinges. Tabs  1 F,  1 G only illustrated in  FIGS. 2A ,  2 B are hinged to the heads of the other flaps, by means of relative score-lines. 
     In the remaining figures these tabs are not represented with the aim of making the technical and functional aspects of the invention clear. 
     With reference to the figures,  100 ,  200 ,  300 ,  400  respectively denote: a store containing a stack P of blanks  150  in a tubular flattened configuration; first means for removing the blank at the bottom of the stack; a drum  300  kept in constant rotation in a direction F, peripherally interested by work stations  20 , identical to one another and angularly equidistanced, each of which is destined to receive, and retain, a blank  150  supplied thereto by the first means; a supply line of crates  450  of which the head facing the drum  300  has been illustrated. 
     With the blank in the flattened configuration, the flaps  1 A- 1 D are distributed according to an external plane (flaps  1 A,  1 B) and an internal plane (flaps  1 C,  1 D); the internal flaps are connected by the score-line  2 A. 
     The walls  100 A,  100 B of the store are mutually positioned such as to have the score-lines  2 A of the blanks of the stack P arranged along a plane  7  (first reference plane); this is satisfied independently of the format of the blanks (see  FIGS. 3A ,  3 B relating, for example, to the maximum and minimum format). 
     The first means  200  are constituted by a flanked pair of arms  6 A,  6 B splined on a shaft  8  made to oscillate in an outward and a return run H and K; if necessary the shaft  8  is made to oscillate by synchronizing means, along an arc of circumference C 1 , coaxial with the shaft  11  of the drum  300 , in operating directions C 1 , and a non-operating direction I 2 . 
     The arms, the mutual distance between which is greater than the thickness of the drum  300 , are positioned so as to be arranged at the end of the outward run, bilaterally with respect to the heads of the drum itself. 
     Each station  20  of the drum  300  is provided with two retaining suckers  22  transversally flanked, i.e. in a direction parallel to the axis of the drum  11 ; a plate  23  is provided upstream of the suckers  22 , aligned with the plane defined by the suckers. 
     The station further comprises, in an internal position with respect to suckers  22 , a portion of the crown wheel  27  that externally enmeshes with a rotating mechanism  25  and is internally supported and guided by idle rollers  28  the axes of which are parallel to the axis C of the crown wheel; the axis C is located downstream (with reference to the direction F of the drum rotation) with respect to the suckers  22  and the plane identified by said suckers  22 . 
     The distance between the axis C of the crown wheel and the plane identified by the axes of the suckers  22  is a predetermined value d. 
     At an end thereof, the crown  27  bears folding means  29  orientated inwardly according to a diameter plane of the crown wheel which, as a result of the oscillation, oscillates about the axis C. 
     In the end position Y 1 , the suckers  12  borne by the arms  6 A,  6 B intercept the first flap  1 A of the two external flaps of the bottom blank from the stack P; the arms are conformed and positioned such that the distance in this position between the reference plane  7  and the plane identified by the axes thereof  12  borne at the free ends of the arms is equal to the above-mentioned predetermined value d (see enlarged detail S of  FIG. 3B ) which is maintained when the blank format is varied. 
     The oscillation of the arms in the outward run H enables transfer of the attached blank from the suckers  12  to a corresponding work station  20 . 
     The mutual phase relationship between the oscillation of the arms and the velocity of the drum  300  is such as to place the pick-up suckers transversally flanked to the station, which causes the impact of the first flap  1 A against the retaining suckers  22 . 
     In phase relation with this impact the pick-up suckers  12  are deactivated and the retaining suckers  22  activated. 
     To avoid stress to the external surface  1 A of the first flap  1 A, the shaft  8  is moved in the operational direction  11 , such as to impose, at least at the moment of impact, a peripheral velocity of the pick-up suction device  12  that is equal to the peripheral velocity of the retaining suckers  22 . 
     Following the disengaging of the suckers  12  from the first flap  1 A, the arms continue forward in the outward run up until reaching the end position Y 2  ( FIGS. 3A ,  3 B): this enables them to make the return run without interfering with the blank drawn in the direction F by the retaining suckers  22 . 
     At the moment of impact of the first flap  1 A on the retaining suckers  22 , the planes defined by the axes of the pick-up suckers  12  and the retaining suckers  22  coincide: it follows that the score-line  2 A connecting the external flaps  1 A,  1 B is arranged along the axis C. 
     In phase relation with the engaging of the first flap  1 A by the suckers  22 , the rotating mechanism  25  imposes the oscillation of the crown wheel  27  in the direction Q, with a consequent oscillation of the folding means  29 , with respect to the axis C, in the opposite direction to the direction F of rotation of the drum. 
     The folding means  29  intercept the second flap  1 B of the external flaps  1 A,  1 B of the blank, causing it to oscillate about the score-line  2 A thereof (i.e. swing around the axis C) by at least 90°; in reality this angle is exceeded (position N in  FIG. 4 ) in order to prevent the elastic return of the score-lines  2 A- 2 D when the folding means cease the action thereof. 
       FIG. 4  shows that the first flap  1 A is resting on the plate  23 : this helps to stabilize the flap during the opening-out of the blank, consequent to the rotation of the second flap  1 B with respect to the score-line  2 A. 
     The combined action of the retaining suckers  22  and the folding means  29  enables obtaining the configuration of the opened-out tubular blank  150  as shown in  FIGS. 3A ,  3 B; this configuration is maintained up to a release zone Z in which the station  20  functionally cooperates with a device  500  for transferring the tubular blank  150  from the station to a crate  450  of the upper branch  470  of the supply line  400 . 
     The line  400  is constituted, in a known way, by a first pair of identical belts  410 , arranged facing on vertical planes, winding in a closed loop on crown wheels, a drive wheel and a driven wheel, of which only the driven wheels  430  are illustrated; the axis  430 A of the crown wheels is parallel to the axis  11  of the drum  300 . 
     The ends of the first segments  415  facing outward are perpendicularly solidly constrained to the belts, with each segment being transversally flanked to a corresponding segment of the remaining belt such as to define pairs of thrust segments  415 ; at the upper branch of the said pair of belts, the front surfaces of these segments define a second reference plane  70 , or reference plane for the tubular blank  150 . 
     The line  400  comprises a second pair of identical belts  420 , correspondingly adjacent to the preceding belts  410  and developing similarly thereto, with respect to which they are operated in synchrony, according to known techniques. 
     Second segments  425  facing outward are perpendicularly solidly constrained to the second pair of belts; in this way pairs of abutting segments  425  are defined. 
     The distance between the pair of abutting segments  425  and the pair of thrust segments  415 , arranged upstream of the abutting segments  425 , identify, at the upper branch  470  of the line  400 , a corresponding crate  450 . 
     According to known techniques, the first and second pairs of belts are operated in a staggered way: for example,  FIGS. 3A ,  3 B relate to the minimum and maximum size of the crate, that is, the minimum and maximum size of the tubular blank  150 . 
     The device  500  is constituted by a rotating member  510  arranged between the longitudinal walls  490  of the line  400  at the head  440  thereof situated opposite the zone Z; this member is coaxial with the crowns  430  of the head and is conformed and positioned such as not to interfere either with the belts  410 ,  420  or with the segments  415 ,  425  borne thereby. 
     The rotating member  510 , for example constituted by a drum or a facing pair of discs, solidly constrained to each other, peripherally bear second pick-up means, constituted for example by pairs of transfer suckers  525  (connected to a vacuum source, not illustrated) angularly equidistanced along the periphery of the rotating member  510 ; the transfer suckers  525  of each pair are transversally flanked, i.e. arranged in a diameter plane of the rotating means. 
     The transfer suckers describe a circular trajectory tangential to the upper branch  470  of the line  400 . 
     As is known, the segments  415 ,  425  are vertical at the upper branch  470 , such as to define the volume of the crate  450  identified thereby; when the belts cross the crown wheels located upstream of the upper branch  470 , the segments are arranged radially such as define there-between a housing, a minimum distance of which, in the rotation direction W of the rotation of the crowns themselves, is greater than the size, in the same direction, of the tubular blank  150  (see  FIGS. 3A ,  3 B,  5 ). 
     The rotating member  510 , in following the pathway facing towards the head  440 , positions a pair of transferring suckers  525  in a corresponding transfer dynamic seating  460 . 
     The mutual phase relation between the movements of the drum  300  and the rotating member  510  are such that the retaining suckers  22  in the station  20  and the transfer suckers  525  of the rotating member  510  are arranged aligned on a same plane X that is diametral both for the drum  300  and for the rotating member  510 . In this situation the suckers  525  intercept the external flap  1 C parallel to the first flap  1 A. 
     In phase relation with the alignment, the folding means  29  disengage from the second flap  1 B, the retaining suckers  22  deactivate and the transfer suckers  525  activate. 
     The abutting segments  425  delimiting the dynamic seating  460  downstream are positioned relative to the suckers  525  in such a way as to counter the closure, due to elastic return, of the tubular blank  150 . 
     The dynamic seating  460  in which the tubular blank  150  hooked, with its flap  1 C, to the transfer suckers  525 , maintains the spatial configuration thereof, not necessarily having a rectangular section, up to when the contrast segments  425 , from being radial, become arranged vertical at the start of the upper branch  470  of the line  400  (position M 1  in  FIG. 3A ): at this point the size of the seating  460  in the direction W gradually decreases and then stabilizes as the segments  415  have also changed from radial to vertical up to defining the volume of the crate  450  (M 2  position of  FIG. 3A ). 
     The deactivation of the transfer suckers  525  occurs in phase relation with the above position, and in practice before it, such as to avoid stress on the flap  1 C when placing the tubular blank  150  between the thrust segments  415  and the abutting segments  425 . 
     During the transfer of the blank tube  150  from the zone Z up to the upper branch  470  of the line, the flap  1 C is abutted by small lateral walls  480 , first curved ( FIGS. 2A ,  2 B) and then straight: in the curved tract the flap is tangential of the walls ( FIG. 3B ), then to go to rest thereof in the straight tract, i.e. in the upper branch. 
     The above-described small walls contribute to stabilizing the blank tube  150 . 
     Subsequently, in a known way in the packing machine, not illustrated, the flaps  1 G are folded to define the bottom of a corresponding container, articles are placed therein, and finally the remaining flaps  1 G are folded to realize the cover of the container. 
     With regard to the change of format, note that the two considered reference planes  7 ,  70  must be respected. 
     In particular the format change is performed as now described. 
     With regard to the first reference plane  7 , the mutual distance between the walls  100 A,  1008  of the store  100  is varied, such that the plane  7  on which the score-lines  2 A of the flattened blanks  150  are arranged at distance d with respect to the plane identified by the collecting suckers  12  when they intercept the first flap  1 A of the bottom blank in the stack: the mutual positioning between the bottom of the stack P of blanks, the first means  200  and the drum  300  is maintained. 
     As regards the second reference plane  70 , which is crucial for the filling and closing operations of the container (corresponding to the tubular blank  150 ) carried out by the above-described packing machine, which presupposes not modifying the positioning of the line in any way with respect to the machine, it is necessary to consider that on varying the format, the distance between the axes  11 ,  430 A, respectively of the drum and the crown wheels  430  of the line  400  also necessarily varies: see  FIGS. 3A ,  3 B, where this distance is indicated by D 1  (minimum format  FIG. 3A ) and D 2  (maximum format  FIG. 3B ). 
     For the above reasons, the apparatus constituted by the store  100 , the first means  200  and the drum  300 , is borne by a same structure (not shown) that can translate in the direction B defined by the line which connects the axes  11 ,  430 A, along a tract that is at least equal to the difference between D 2  and D 1 . 
     The above description has considered a particular embodiment of the drum  300 , the work stations of which intervene to vary the shape of the blank from flattened to tubular without causing lacerations and/or scoring and/or creasing and/or stress on the second flap  1 B, which is the one subjected to the action of the folding means. 
     The ambit of protection of the invention is understood to extend independently of the modes with the blank is opened out.

Technology Category: 7