Patent Publication Number: US-8992401-B2

Title: Automatic machine and method for making curvilinear packing boxes

Description:
TECHNICAL FIELD 
     The present invention relates to an automatic machine for making and covering paper or cardboard packing boxes which have a curvilinear outline. 
     BACKGROUND ART 
     Prior art devices for forming curvilinear boxes usually consist of machines which assemble a body which has a cylindrical wall with a separate bottom having the same outline and which is normally joined to the wall by gluing. 
     Covering the boxes consists of subsequent application of a layer of covering paper which gives the end product the desired outer finish. 
     However, prior art machines have several disadvantages in the automatic production of high quality covered boxes, that is to say, in which in the finished box the presence of separate parts, such as the base and the cylindrical wall cannot easily be seen or felt. 
     A second disadvantage is the fact that it is not possible to automatically and efficiently perform the entire processing of a covered curvilinear box, starting with assembly of the separate parts, the bottom and the wall, up to covering of the finished product. 
     DISCLOSURE OF THE INVENTION 
     A first aim of the present invention is to overcome the problem of automatic production of covered paper or cardboard boxes which have a curvilinear, preferably circular shape. 
     A second aim of the invention is to propose a machine and method for automatically making covered paper or cardboard curvilinear boxes with high productivity and at the same time able to make high quality boxes. 
     The technical purpose indicated and the aims specified are substantially achieved by a machine and method for making boxes comprising the technical features described in one or more of the claims herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further features and advantages of the present invention are more apparent in the detailed description below, with reference to a preferred, non-limiting, embodiment of the invention, illustrated in the accompanying drawings, in which: 
         FIG. 1  is a schematic view of steps for assembling a curvilinear wall with a base; 
         FIG. 2  is an exploded schematic view of devices in accordance with the invention for stably joining with a pre-glued disk of covering paper the base and the curvilinear wall of  FIG. 1 ; 
         FIGS. 3 and 4  are schematic views of successive steps of the application of a pre-glued disk by the devices of  FIG. 2 ; 
         FIG. 5  illustrates a carrousel unit with a covering station in accordance with the invention; 
         FIG. 6  shows a detail of the carrousel from  FIG. 5  with a box at the covering step; 
         FIG. 7  shows another detail of the box covering step; 
         FIG. 8  shows yet another detail of the box covering step; 
         FIG. 9  is a schematic view of the step of transferring an assembled box to the aiming and forming stations; 
         FIG. 10  shows an example of a succession of processing steps of the method in accordance with the invention; 
         FIG. 11  shows a succession of steps for the in line production of tubes intended to constitute the wall of cylindrical boxes; 
         FIG. 12  shows a detail of a device for centring an open tube along a feed line; 
         FIG. 13  shows a detail of a device for searching for and aligning along a feed line a glued disk for covering the bottom of the box; 
         FIG. 14  shows a detail of a device for aligning along a feed line a sheet which will form the box lateral covering; 
         FIG. 15  shows a detail of a device for box lateral covering; 
         FIG. 16  shows a detail of a station for box lateral covering; 
         FIG. 17  shows a detail of a folding over device in a station for box lateral covering; 
         FIG. 18  shows a detail of a pair of tailstocks in a box covering station; 
         FIG. 19  is a schematic illustration of operation of a machine in accordance with the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION 
     With reference to the accompanying drawings, a machine is described for making curvilinear boxes  6 , obtained starting with a curvilinear cylindrical wall  1  connected to a bottom or base  2 . 
     It should be noticed that according to the present invention, the wall  1  may be made from pre-formed tubes, or may be formed in a line in a suitable operating station upstream of the machine. 
     In the example in  FIG. 11 , a station for forming cylindrical tubes may have, one after another, a cardboard blank (rough or joined) magazine from which the cardboard, having dimensions equal to the length of the box to be formed, is picked up and moved to a calendering station in which the tube is formed by sealing the free ends of the cardboard. 
     Once the cylindrical tube has been formed, it is unloaded and fed to a finished tubes magazine. 
     Preferably, and with reference to  FIG. 1 , the box  6  has a circular outline, and is obtained by inserting the bottom  2  in a wall having a round cross-section  1  using a gripper element  3 , for example of the suction cup type, until one end  24  of the wall is closed by mechanical interference. 
     With reference to  FIGS. 2-4 , the bottom  2  and the wall  1  may be stably joined by applying a pre-glued disk  7  to the end  24  of the box. 
     Preferably, and with reference to  FIG. 9 , the disk  7  has radial dimensions slightly greater than the outer diameter of the box  6  and travels resting on a conveyor belt  27   a  to an aiming station P. 
     In the station P, the box  6  may be engaged by a gripper element  5  with vertical stroke, positioned above the pre-glued disk  7  and comprising a cylindrical body  4  which can be precisely inserted in the box  6  until contact is made with a flange  31 , so as to place the box  6  centred on the disk  7  over the latter and glue it there. 
     In particular, the box is centred by devices which search for the position of the disk (of the known type in the sector), which having identified the position of the disk centre the box with precise vertical alignment. 
     Once centring is complete, the box  6  and the disk  7  are moved to a forming station F in which there is a toroidal supporting surface  8  having an opening  9  with the shape and dimensions corresponding precisely to the outer outline of the box  6 . 
     On the opposite side to the opening  9 , in the example described, there may also be a plate  10 , if necessary mounted on springs  11 , having dimensions such that it can be drawn near to the opening  9  in contact with the disk  7 . 
     In operation, the box  6  with the glued disk  7  is lowered to the opening  9 , and the plate  10  draws near to the non-adhesive side of the disk  7 . 
     Continuing the box  6  stroke through the opening  9 , the spring  11  yields, the bottom of the box passes through the opening  9  in a precise fashion, and the portion of the disk  7  extending beyond the opening  9  is pressed onto the stretch of wall  23  adjacent to the bottom, thus stably joining the bottom  2  and the wall  1  of the box  6 . 
       FIGS. 5 to 9  schematically illustrate a covering station R in accordance with the invention, in which the box  6  is transferred, passing from a vertical orientation to a horizontal orientation, by tipping means able to engage the box exiting the forming station F and rotate it until it adopts a horizontal orientation, after which the box  6  is received by the covering station R, if necessary passing through an intermediate magazine for boxes  6  which are not yet laterally covered. 
     According to the invention, the station R is part of a carrousel unit  26  which rotates, driven by a drive unit  27  and comprises a plurality of operating stations S, at least one intended for a step of loading a formed box to be covered, and, after covering, for a finished box unloading step. 
     The stations S are not described in detail, as they are not themselves the subject matter of the invention. 
     In the example described, a box  6  already formed is being processed in a covering station R, and is already positioned on a spindle  19  mounted at the end of a carrousel  26  arm  25 . 
     The dimensions of the spindle  19 , which may be expanded on command, are such that it engages in the box  6  and can rotate about an axis  20  driven by a drive unit  14 . 
     In the embodiment illustrated, the longitudinal motion of the motor  14  is guided by fixed prismatic guides  18 , schematically illustrated in  FIG. 5 . 
     According to the invention, in the station R, the spindle  19  rotates the box along the axis  20  in such a way that it is synchronised with the arrival of a pre-glued covering sheet  12 , fed transversally to the axis  20  until it makes contact with a box  6  generatrix along which covering takes place. 
     The box speed of rotation, and the sheet  12  linear feed speed are fixed so that the tip speed at the covering point coincides with the sheet  12  speed. 
     Alternatively, after a first sheet  12  gluing stretch on the box  6 , covering may continue by dragging the sheet  12  in the absence of forced sheet feed. 
     The sheet  12  longitudinal extent and length are also such that it covers the entire outer wall  1  and leaves an edge  22  extending beyond it at the box  6  open end  21 . 
     It should be noticed that, in other embodiments, the sheet  12  may be fed in the form of individual pre-cut sheets, or there may be a step of cutting a continuous sheet to size. 
     In particular with reference to  FIGS. 7 and 8 , the station R also comprises edge turning down folders  17 , positioned close to the open end  21  of the box  6  to interfere with the passage of the edge  22  during box covering and guide the edge so that it folds towards the inside of the box and covers the open edge of the box. 
     Covering of the open end  21  is then preferably completed by a pair of pressure rollers  13  belonging to the station R, positioned straddling the end  21  to press the edge  22  against the wall  1  during box rotation. 
     It must be emphasised that the layout of the drive units and the guides described is by way of example, but its shall be understood that different mechanisms and mechanical solutions may be used to rotate the spindle  19  and perform the covering and edge turning down steps. 
     For example, in different solutions, both box covering and edge turning down may be carried out in the same station R. In such a case, there may be only one motor positioned at the station R and having a coupling with which the motor, for example by means of axial sliding, engages with and disengages from the carrousel spindle. 
     In a different solution there may be several motors, if necessary with hook-release coupling, positioned at several operating stations R, S of the carrousel set up to perform separate covering or edge turning down steps. 
     Once covering and edge turning down are complete, the finished box is moved by the carrousel away from the station R and to a subsequent unloading station S, then sent on for subsequent processing or storage. 
       FIGS. 10 and 11  illustrate, by way of example, a sequence of the steps described above for the automatic production of covered boxes disclosed, involving: 
     use of magazines for the bottoms  2  and cylindrical walls or tubes  1 , 
     assembly of the bottom and the wall to form the box  6 , 
     movement of the box  6  to the aiming station P with a pre-glued sheet  7 , 
     sheet  7  edge turning down on the wall  1 , 
     movement of the box with the bottom covered towards the station for box lateral covering with a pre-glued sheet, 
     turning down the lateral covering sheet on the open edge of the wall, 
     unloading with movement of the covered box. 
       FIG. 19  is a schematic illustration of operation of a machine in accordance with the invention in a preferred embodiment illustrated in particular in  FIGS. 12 to 19 . 
     According to the diagram in  FIG. 19  and with reference to  FIGS. 12 and 13 , a succession of tubes  1  is fed along a belt  28  along which a fork  29  operates, centring the open tubes relative to insertion of the bottoms  2 , which occurs as described with reference to  FIG. 1 . 
     In more detail, the fork  29  is driven with a backward and forward movement away from and towards the line by feed means  320 , for example comprising belts  320  connected to the fork  29  and driven by a motor  33 . 
     The fork  29  preferably comprises two arms  35  slidably mounted on respective guides  37  and able to draw near each other thanks to the action of a movement element  36 , for example a belt driven by a motor (not illustrated), the front of the arms being equipped with cells  38 . 
     During operation, the tubes  1  are guided along the line by longitudinal guides  47  passing through the openings  340  in the arms  35  and the fork  29  is repeatedly moved forward in a way that is synchronised with tube  1  feed along the line so that the cells  38  detect the position of the tube  1  held between the arms  35  being drawn near, and therefore positioned along the line in such a way that it is centred relative to the predetermined axis  39  for insertion of the bottom  2  in the tube  1  shown in  FIG. 19 . 
     Once the open tube has been assembled with the bottom  2 , the boxes  6  to be covered are conveyed by the belt  28  towards the belt  30  for feeding sheets of paper  7  for covering the bottom which are applied to the boxes  6  as described with reference to  FIGS. 2 to 4 . 
     Advantageously, along the belt  30  there is a device A 1  for centring the bottom covering sheets  7  relative to the boxes  6 , illustrated in  FIG. 13 . 
     The device A 1  comprises a bridge  40  transversal to the belt  30  conveying the bottom covering sheets  7  and along which a box  6  gripper mechanism  41  can slide, the mechanism comprising a pair of jaws  42  supported by a transversal member  43  and able to slide along it on command. The transversal member  43  can in turn slide on command along the bridge  40  along suitable guides  44 . An optical sensor  60  is applied at least at one of the gripper jaws  42 . 
     The device A 1  also comprises a sensor  45  located above the belt  30  near to the bottom covering sheet  7  transit line and supported cantilever style by a carriage  46  able to slide along the bridge  40  guides  44 . 
     In operation, the boxes  6  arrive at the device A 1  which grips them with the jaws  42  and conveys them over the belt  30  by movement of the transversal member  43  along the bridge  40 . 
     The extent of the movement by the transversal member  43 , and therefore the precise centring of the boxes  6  relative to the bottom covering sheet  7  is guaranteed by the reading of the sensor  45  which identifies the position of the bottom covering sheets  7  on the belt  30  in direction Y and transmits it to the control unit which controls the motion of the transversal member. 
     Moreover, once the box  6  is centred relative to Y, the sensor  60  issues the command to stop the belt  30 , thus centring the box  6  and the bottom covering sheet  7  relative to the axis X. 
     The sensors  45  are preferably optical and detect the transit of the maximum dimension of the bottom covering sheet  7  and therefore the position of its centre on the belt relative to the axis Y. 
     Once the bottom covering sheet  7  has been applied, the boxes  6  are sent to the covering station F shown in  FIG. 9  for completion of the covering of the bottom of the box and lateral turning down of the edge  23  of the bottom covering sheet  7 . 
     When that has been done, the boxes  6  are tilted into a horizontal position and placed on a spindle  31  belonging to the carrousel  26  standing by at a first station S. 
     The mechanism for box  6  tilting and placing on the spindle  31  is not illustrated, since it is not part of the present invention. 
     During the subsequent step, with reference to  FIGS. 14 and 15  the carrousel rotates and brings the spindle to the covering station R, and in particular the first sub-station R 1  located at the lateral covering sheet  12  arrival plane. 
     Advantageously, along the sheet  12  feed plane there is a device A 2  for aligning the sheet  12  position and direction of feed relative to the box  6  mounted on the carrousel  26  spindle. In particular, the device A 2  comprises one or more sensors  53  able to detect the position of a longitudinal edge  32  of the sheet  12  on the feed belt  51 , and a pair of suction cups  48  (or mechanical gripper systems such as grippers and the like) able to move on command transversally to a predetermined direction “d” of sheet  12  alignment. The suction cups  48  may be mounted on carriages  49  sliding on guides  50  parallel with the longitudinal edge  32 . 
     In operation, the direction “d” is defined in such a way that it is incident to the edge  52  of the box  6  mounted on the spindle  31 . 
     As the sheet  12  is fed forwards, the sensors  53  detect the position of the edge  32  relative to the direction “d” so that the suction cups  48  can grip the sheet  12  and pull it transversally until the edge  32  coincides with the direction “d”. 
     Once the alignment has been found, box  6  lateral covering in the station R 1  can take place precisely, preferably with the aid of a pressure element  54  that can be drawn near the box  6  to make the sheet  12  adhere to the outer walls of the box. 
     Also with reference to  FIG. 19 , once the lateral covering has been applied, another rotation of the carrousel  26  brings the box  6  to a second covering sub-station R 2 , better described with reference to  FIGS. 17 and 18  and in which there is advantageously a folding over device  34  for completing box  6  lateral covering. 
     In operation, the spindle  31  rotates the box  6  to which the lateral covering has already been applied, and the folding over device  34  is moved forwards, for example by means of a carriage  55  able to move on a guide  56 , until it interferes with the excess edge  22 , forcing it to fold towards the inside. 
     Once edge  22  folding is complete, it can be folded over the inside of the box by means of a counter-mould  57  shown in  FIG. 16 , able to move relative to the spindle  31  and able to be precisely inserted in the box to make the edge  22  adhere to the inner wall and cover the open end  21 . 
     Once folding over is complete, the carrousel  26  performs another rotation, bringing the covered box to an ejection station E, from which the boxes are sent for storage or for further processing. 
     At the covering station R 1  and the folding over station R 2  there are preferably disks or tailstocks  58 , schematically illustrated in  FIG. 18 , which during operation can draw near and make contact with the boxes  6  being processed to guarantee regular covering and folding over during rotation of the spindles  31 . 
     Similarly, in place of at least one of the tailstocks  58  there may be contact elements designed to keep the edges of the box mounted on the spindle in the correct reference position. 
     The invention described above is susceptible of industrial application and may be modified and adapted in several ways without thereby departing from the scope of the inventive concept. Moreover, all details of the invention may be substituted by technically equivalent elements.