Abstract:
A self-dimensioning machine for closing upper flaps of parallelepiped boxes including a base with support surface for the boxes, a couple of drive belts placed at the two sides of the support surface for engagement with the sides of the boxes, a device for detecting the position and horizontal dimensions of the boxes for controlling the movement of the drive belts, a rod pivoted on a head above the support surface descending from a rest position to engage, straighten and partially close the front flaps of the boxes, a vertically mobile touching group for detecting the height of the boxes and successively to the head in the advancement direction of the boxes, a central longitudinal guide carried by the touching group and positioning itself in a horizontal position above the support surface at a height corresponding to the height of the boxes for completing the closing of the front flap.

Description:
FIELD OF THE INVENTION 
   The present invention refers to a device for straightening and closing the rear flap for a self-dimensioning machine for closing parallelepiped boxes. 
   BACKGROUND OF THE INVENTION 
   Machines of various kinds are known for closing the upper flaps of cardboard parallelepiped boxes before applying adhesive sealing tape. 
   In particular so-called “self-dimensioning” machines are known, that accept boxes of various widths and heights, automatically adapting their operative parts to the dimensions of the box. 
   Even more in particular, “self-dimensioning” machines are known that comprise a base with support surface for resting the boxes on, a couple of drive belts that can be motorised placed at the two sides of said support surface and that can be brought close to each other to make a drive engagement with the sides of the boxes and a head above said support surface, that carries suitable devices for closing the front, rear and side flaps of the boxes and can be commanded to descend from a rest position for engaging the above-mentioned devices with the upper flaps of the boxes and thus providing for their closure. Suitable mechanical or photocell or other sensors provide for the automation of the various movements in accordance with the position and the dimensions of the boxes. 
   One problem encountered by the machines of this type is represented by the fact that the boxes often have the flaps partially folded outwards, therefore it is first necessary to straighten them into a vertical position and then to close them. 
   SUMMARY OF THE INVENTION 
   In view of the state of the technique the object of the present invention is to make a device for closing the front flap for self-dimensioning machines of the type described above, that enables to carry out in rapid succession and with full efficiency first the straightening of the flap from a possible partially outwardly folded position and then the rotation of the same flap for reaching the closing position. 
   In accordance with the invention this object is achieved with a device for closing the front flap in a self-dimensioning machine for closing the upper flaps of parallelepiped boxes of the type comprising a base with surface for supporting the boxes, a couple of drive belts that can be motorised placed at the two sides of said support surface and that can be brought close to each other to make a drive engagement with the sides of the boxes, a head above said support surface, that carries devices for closing the front, rear and side flaps of the boxes and can be commanded to descend from a rest position to engage the above-mentioned devices with the upper flaps of the boxes and provide for their closure, and means for detecting the position and the dimensions of the boxes for the automatic command of the movements of the machine, characterised in that it comprises a rod for straightening the front flap, that is pivoted on said head and is stressed to keep itself flexibly in a vertical position, a vertically mobile touching group for detecting the height of the boxes and, successively to said head in the feed direction of the boxes, a central longitudinal guide for completing the closing of the front flap, that is carried by said touching group so as to position itself in a horizontal position above said support surface at a height corresponding to the detected height of the boxes to meet the front flap partially closed by said straightening rod and to complete its movement to the closing position. 
   In this manner, whatever the height of the box is, first the front flap is straightened from an eventual position folded outwards and then its partial folding inwards and its complete folding to the closing position are carried out. Thus the certainty of effective and complete closing of the box is obtained, whatever its height is. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     An embodiment of the present invention is illustrated as non-limiting example in the enclosed drawings, in which: 
       FIG. 1  shows in a side view, in the position awaiting a box, a machine for closing parallelepiped boxes that uses a device for straightening and closing the front flap in accordance with the present invention; 
       FIG. 2  shows the same machine in a front view, again in said awaiting position; 
       FIG. 3  shows the same machine, again in said awaiting position, sectioned in a plan above the advancement surface of the boxes; 
       FIG. 4  shows the machine in a side view at the moment the box enters; 
       FIG. 5  shows the machine in a front view in the working position of  FIG. 4 ; 
       FIG. 6  shows the machine in a side view immediately after the entrance of the box; 
       FIG. 7  shows the machine in a front view in the working position of  FIG. 6 ; 
       FIG. 8  shows the machine in a side view in a successive phase of advancement of the box; 
       FIG. 9  shows the machine in a front view in the working position of  FIG. 8 ; 
       FIG. 10  shows the machine in a side view at the moment the front flap of the box is straightened; 
       FIG. 11  shows the machine in a side view at the moment the closing movement of the front flap of the box starts; 
       FIG. 12  shows the machine in a side view at the moment the rear flap of the box is straightened; 
       FIG. 13  shows the machine in a front view in the working position of  FIG. 11 ; 
       FIG. 14  shows the machine in a side view at the beginning of the closing movement of the rear flap of the box; 
       FIG. 15  shows the machine in a front view in the working position of  FIG. 13 ; 
       FIG. 16  shows the machine in a side view at the end of the closing movement of the rear flap of the box; 
       FIG. 17  shows the machine in a front view in the working position of  FIG. 16 ; 
       FIG. 18  shows the machine in a side view at the end of the closing movement of the front flap of the box; 
       FIG. 19  shows the machine in a front view in the working position of  FIG. 18 ; and 
       FIGS. 20-24  show enlarged details of several mechanisms comprised in the machine of the previous figures. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The machine shown in the drawings is provided for the straightening and the closing of the end, front and rear flaps, of parallelepiped boxes fed in succession onto a support surface  1  formed by a succession of idle rollers  2  supported by a base frame  3  (FIG.  3 ). 
   The succession of idle rollers  2  is preceded, in the advancement direction of the boxes (from right to left looking at FIG.  1 ), by a motorised roller  4  in turn preceded by a stopping blade  5 , that can be raised and lowered by activating a pneumatic cylinder  6 . 
   At the two sides of the support surface  1  two chain conveyors  7  are provided that can be motorised thanks to an electric motor  8 , and that can be brought closer to each other or further away from each other by means of the use of any device known in itself. 
   From the base frame  3  two fixed portals  9  and  10  extend upwards, the first of which supports, on one part, a succession of photocells  11 ,  12  and  13  and, on the other side, a corresponding succession of mirrors  14 ,  15  and  16  capable of reflecting backwards the light rays emitted by the above-mentioned photocells (FIGS.  1  and  2 ). 
   The fixed portal  9  also supports along its side uprights a couple of guide rods  17  for the vertical sliding of a mobile portal  18 , that can be raised and lowered by means of a pneumatic cylinder  19  placed along one of its above-mentioned uprights. A brake group  20  is provided for, whose task is to stop the descent of the mobile portal  18  when required. A couple of bars  21  is fixed to the mobile portal  18 , and bear photocell  22  and a facing mirror  23 . A notch reader  24  is also fixed to one of the two bars  21  and cooperates with a holed band  25  that extends vertically along one of the uprights of the fixed portal  9  (FIGS.  1  and  2 ). The constructive details of the notch reader  24  and the holed band  25  are shown in enlarged scale in FIG.  20 . 
   The mobile portal  18  also bears centrally a head or trolley hollow internally  26 , on which a rod  28  is pivoted in  27  destined to straightening and folding the front flap of the boxes. The rod  28  is clutched by means of a pneumatic cylinder  29  fitted with pressure regulator (not shown), that shows resistance to the rotation of the rod  28  in relation to the normal vertical rest position that is illustrated in  FIGS. 1 and 2 . The constructive details of the pin  27 , of the rod  28  and of the cylinder  29  are shown in enlarged scale in  FIGS. 21 and 22 , where  FIG. 22  is a section view according to the line XXII—XXII of FIG.  21 . 
   The trolley  26  also bears, sliding on a horizontal splined pin  30  thanks to a splined bushing  31 , a rod  32  destined to straightening and folding the rear flap of the boxes. The splined pin  30 , and with it the bushing  31  and the rod  32 , is commanded to rotate from the nearly horizontal position of  FIG. 2  to the vertical position of  FIGS. 12 and 13  by a pneumatic cylinder  33  to which an end of stroke sensor  34  is associated, while the translation of the bushing  31 , and thus of the rod  32 , along the splined shaft  30  from the backward position of  FIG. 1  to the forward position of  FIG. 14  is commanded by a pneumatic cylinder  35  to which an end of stroke sensor  36  is associated. The constructive details of the pin  30 , of the bushing  31 , of the rod  32  and of the cylinders  33  and  35  with relative sensors  34  and  36  are shown in enlarged scale in  FIGS. 23 and 24 , where  FIG. 24  is a right view in relation to FIG.  23 . 
   The fixed portal  10  bears in turn a touching group  37  that can be moved vertically along guide rods  38  by means of a pneumatic cylinder  39  with brake group  66  ( FIG. 1 ) and bears a notch reader  40  cooperating with a vertical fixed holed band  41 . The notch reader  40  and the holed band  41  are all similar to the reader  24  and to the holed band  25  shown in FIG.  20 . 
   The touching group  37  also bears an L lever  42 , pivoted in  43  (FIG.  1 ), whose task is to carry out the closing folding of the rear flap of the boxes and is connected by means of a pin joint  44  to the stem of a pneumatic cylinder  45  fitted with end of stroke sensor  46 . 
   Finally a central longitudinal guide  49  is pivoted in  68  on the touching group  37 , and is also connected at the rear to the same touching group  37  by means of a connecting rod  50  pivoted in  51  and  52 , with which a spring  53  reacts. The guide  49  is normally in a slightly inclined position in relation to the horizontal one (FIG.  1 ), but can be moved to a horizontal position ( FIG. 18 ) by activating a pneumatic cylinder  47  to which it is connected by means of a pin joint  48 . 
   Through effect of the structure described above the machine illustrated in the drawings operates in the following manner on a parallelepiped cardboard box  60 , which is presented with upper flaps open, and in particular with front flap  61  and rear flap  62  partially rotated outwards as shown in  FIG. 4 , on a sliding surface  63  placed in continuation of the support surface  1 . 
   The first phase of the working cycle of the machine shown in the drawings is illustrated in  FIGS. 4 and 5 . The box  60  coming from the sliding surface  63  arrives at the entrance of the machine, where it stops against the stop  5 , and activates the photocell  11 , whose command starts the cycle. 
   The activation of the photocell  11  starts off the detection of the box height. With the photocell  22  free, the trolley  26  carrying the photocell  22  starts the descent, guided by the rods  17  and commanded by the pneumatic cylinder  19 , until the photocell  22  is activated. During the descent of the trolley  26  the notch reader  24 , in one with the trolley  26 , detects by means of the holed band  25  the height position of the trolley itself. When the photocell  22  detects the box  60 , the descent of the trolley  26  is blocked by means of the activation of the brake group  20 . 
   The activation of the photocell  22  commands the entrance into the machine of the box  60  lowering the stop  5 , activated by the cylinder  6 , and starting the motorised roller  4  and the motor  8 . At the same time the touching group  37  starts getting closer to the box  60  under the command of the pneumatic cylinder  39  and with the guide of the rods  38  (FIGS.  6  and  7 ). By means of the notch reader  24  and the relative holed band  25  the height at which the trolley  26  is stopped is known. The notch reader  40  with respective holed band  41  enables the position of the touching group  37  to be controlled and temporarily stops the descent at about 10 cm from the box; this is done to make the machine cycle faster. The box  60  advances, driven by the motorised roller  4 , until the photocell  12  ( FIG. 8 ) is activated. 
   The activation of the photocell  12  commands the closing of the driving belts  7 , which, coming into contact with the sides of the box  60  and being the same in movement by means of the motor  8 , drive the same inside the machine. 
   During its advancement the box  60  activates the photocell  13 , which in this phase does not activate any function, and comes into contact with the rod  28 , which at first straightens the front flap  61  of the box ( FIG. 10 ) and successively starts folding it inwards (FIG.  11 ). During rotation, the rod  28  extends the cylinder  29  (FIG.  21 ), which opposes resistance, can be regulated by means of special pressure regulator, that enables the front flap of boxes of different hardness to be folded. During the advancement the box  60  frees the photocell  11 , which by means of the cylinder  6  commands the raising of the stop  5  in order to block the entrance of the successive box  65  into the machine (FIG.  12 ). 
   The box  60  continues advancing until it frees the photocell  13 , which commands the stop of the motor  8  and therefore of the box  60 . At this point the front flap  61  of the box  60  has been almost completely folded inwards and at the same time when the box stops the straightening the rear flap  62  starts up. The rod  32  destined to straightening the rear flap  62  is activated by the pneumatic cylinder  33  so as to go to the almost horizontal rest position of  FIG. 2 , suitable for enabling the passage of the boxes, to the vertical position of FIG.  13 . Reaching the vertical position, the sensor  34  activates the pneumatic cylinder  35 , that command the translation of the splined bushing  31 , and thus of the rod  32 , along the splined shaft  30  from the position illustrated in a continuous line in  FIG. 23  to that illustrated in dots and lines in the same figure. The rod  32  thus straightens the rear flap  62 . 
   When the translation has been made, the sensor  36  associated to the pneumatic cylinder  35  commands the activating of the pneumatic cylinder  39  for the descent of the touching group  37  for detecting the height of the box. The touching group  37  starts the descent and by means of the lever  42  starts folding the rear flap  62  inwards (FIGS.  14  and  15 ). 
   During the descent of the touching group  37  the lever  42  continues rotating and folding the rear flap  62  and at the same time commands the return of the pneumatic cylinder  45 . When the lever  42  reaches the horizontal position corresponding to the completion of the closing of the rear flap  62  of the box  60 , the magnetic sensor  46  associated to the pneumatic cylinder  45  detects the complete return of the latter and consequently, in combination with the reader  40  and the holed band  41 , determines the detection of the height of the box (FIGS.  16  and  17 ). 
   The magnetic sensor  46  also commands the stopping of the descent of the touching group  37 , by activating the brake group  66 , and through the pneumatic cylinder the lowering of the rear part of the central guide  49 , which positions itself horizontally and thus causes the completion of the closing of the front and rear flaps  61  and  62  (FIGS.  18  and  19 ). The connecting rod  50  and the spring  53  make the guide  49  tilting so as to also permit the passage of any over-filled boxes. The magnetic sensor  46  also commands the complete rotation of the rod  28  for folding the front flap  61  so as to disengage it from the box, the repositioning of the rod  32  for folding the rear flap  62  and the restart of the motor  8  and of the belts  7  for starting the box  60  again. In this phase, by means of the notch reader  40  and the relative holed band  41 , the positioning of the touching group  37  is detected, definitively, and consequently the height of the box  60  to transmit to the successive station, that provides for the closing of the side flaps  67  of the box  60  and the application of the sealing tape at the top of the box. 
   The whole set-up then returns to the initial position of FIG.  1 . To prevent useless excursions of the trolley  26 , and therefore increase the productivity of the machine, the positioning of the trolley  26  comes about with the following logics:
         photocell  11  activated: box present at machine input;   photocell  22  activated: the box in input has a height exceeding that of the position of the trolley  26 , for which the latter rises until the photocell  22  is deactivated;   photocell  22  deactivated, the box in input has a lower height than that of the position of the trolley  26 , for which the latter lowers until the photocell  22  is activated;   photocell  11  deactivated: no box in waiting at machine input and therefore the trolley  26  rises up to the upper limit switch. When the height of the box is detected, the cycle starts up again as has already been described.