Abstract:
A case sealer for overlap flap type boxes wherein the major flaps extend greater than ½ the width of the carton. The case sealer uses a folding shoe for folding the inner major flap and then holding the inner major flap and a trailing minor flap in folded position until a plough folds a leading minor flap and the overlies the inner major flap and at least the leading minor flap at least until the outer major flap traps the trailing and leading flaps and thus the inner major flap in folded position.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a method and apparatus for sealing cartons, particularly overlap flap type cartons, more specifically the present invention relates to an inline sealing system wherein the carton being sealed is moved in substantially a straight line for application of adhesive and the flap folding operations in a overlap flap box closure system 
     BACKGROUND OF THE INVENTION 
     In the closing of overlap flap boxes (i.e. cartons wherein at least one and generally both the major flaps each have an area and shape essentially more than half the width of the carton) it is the practice to direct the carton in a first direction and apply adhesive and particular closing steps to the carton flaps and then move the carton in a direction at 90° to the first direction to complete the adhesive and closing operations. Generally these machines are relatively expensive and operate relatively slowly. Mechanical or flap interference in folding and holding-down flaps is a major problem in the closing of overlap flap cartons. 
     Inline flap closing systems for handling and closing ordinary flap type boxes (as opposed to overlap flap boxes or cartons) are known (see for Example U.S. Pat. No. 5,440,852 issued Aug. 15, 1995 to Lam). In this particular system the leading flap (leading in the direction of movement of the carton through the machine) is first folded, then the trailing flap is folded followed by simultaneous folding of the two flaps with their longitudinal axes parallel to the direction of flow through the machine. In the arrangement the leading and trailing flaps are minor flaps and the other two flaps are the major flaps. This system does not lend itself without substantial modification to closing of overlap flap cartons or boxes. 
     BRIEF DESCRIPTION OF THE PRESENT INVENTION 
     It is the main object of the present invention to provide a simplified system for closing overlap flap type boxes or cartons. 
     It is an object of the present invention to provide a method and apparatus to fold four (4) flaps for closing one end of the box ore carton in a particular sequence so as to have both flap folding and flap holding occur without interference. 
     It is an object of the present invention to provide a method and apparatus for inline movement (i.e. movement along a straight line) during adhesive application and flap folding to close an overlap flap box or carton. 
     Broadly the present invention relates to a method and apparatus for closing a carton having mutually perpendicular side and end walls and an inner major overlap flap and an opposed outer major overlap flap each having dimensions more than half the width of said carton and each foldably connected along one side via a longitudinal fold line to it adjacent of said side walls and a pair of opposed minor flaps each foldably connected along one side via a transverse fold line to its adjacent of said end walls, each said minor flap having a length corresponding to a that of said end wall of said carton to which it is connected and a width extending from said transverse fold line to a free edge of said minor flap significantly shorter than length of said fold line comprising positioning said carton with said major and minor flaps in planes substantially parallel to said end or side wall to which it is connected, moving said carton with said flaps so positioned along a path in a direction parallel to said planes in which said major flaps are positioned, retaining said major flaps in their respective said plane, applying adhesive to an inner surface of said outer major flap and to an outer surface of said inner major flap while said flaps are so retained, folding said inner major flap into a position substantially perpendicular to said side wall to which it is connected without disrupting said adhesive applied to said inner major flap, folding the one of said minor flaps trailing in said direction of movement into a position overlying said inner major flap as said carton is moved long said path, holding said inner major flap and said trailing minor flap in folded position and folding another of said minor flaps leading in said direction of movement over said inner major flap as said carton is moved along said path, holding said trailing and said leading minor flaps and said inner major flap in folded position and folding said outer major flap into overlying relation with said minor flaps and said inner major flap and pressing said outer major flap onto said minor and said inner major flap. 
     Preferably said without disrupting said adhesive applied to said inner major flap comprises applying said adhesive to said inner flap in a pattern leaving a longitudinal portion of said inner major flap extending parallel to and adjacent to said fold line connecting said inner major panel to it adjacent side wall and along the full length of said inner major flap substantially free of adhesive to provide an adhesive area free area on said outer surface of said inner major flap wherein a folding element used to apply pressure to said inner major flap for said folding of said inner major flap into said position substantially perpendicular to said side wall may contact said outer surface of said inner major flap. 
     Preferably said longitudinal portion extends over at least 40% of said outer surface. 
     Preferably said pattern also leaves a central portion between adhesive applied areas extending said adhesive free area from said longitudinal portion between said adhesive applied areas toward a free edge of said inner major flap remote from said fold line connecting said inner major flap to its said side wall. 
     Preferably said pressing of said outer flap occurs in a pressing station when said carton is stationary. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
     Further features, objects and advantages will be evident from the following detailed description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings in which; 
     FIG. 1 is an isometric illustration of the apparatus of the present invention with parts broken away for clarity of illustration. 
     FIG. 2 is a schematic illustration of the important steps of the present invention in the sequence applied to close the flaps. 
     FIG. 3 is a plan view of the flap  22  showing the adhesive pattern. 
     FIG. 4 schematically shows an alternative arrangement for closing the trailing minor flap of the carton. 
     FIG. 5 is a schematic illustration of the action of the inner major flap-folding shoe holding down the trailing minor flap. 
     FIG. 6 is a schematic illustration of the action of the outer major flap-folding plough folding down the outer major flap while the minor flaps and inner major flaps are held in folded position by the leading minor flap folding plough. 
     FIG. 7 illustrates and alternative compression system for compression position F. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The structure of the machine has been shown in FIG. 1 with a box or carton  10  in position to be introduced to the folding and closing equipment  12 . The box  10  illustrated is a full overlap flap box having a pair of opposed sidewalls  14  and a pair of opposed end walls  16 . Foldable connected one to each of the sidewalls by fold lines  18  and  20  respectively are an inner major flap  22  and outer major flap  24 . Each of the major flaps  22  and  24  have lengths substantially equal to the length or their respective side  14  (i.e. of the fold line  18  (or  20 )) and a width D 1  measured from the fold line  18  or  20  to the free edge  25  of the respective flap  22  or  24  is more than half the full width of the end wall  16 . I.e. of the length of fold line  32 . The width D 1  of each of the flaps may if desired be made sufficiently large so that the area of each of the major flaps  22  and  24  substantially corresponds with the cross section of the box  10 . 
     A pair of minor flaps  26  and  28  one, the leading minor flap  26 , leads in the direction of movement of the box  10  through the equipment  12  as indicated by the arrow  30  and the other, the trailing minor flap, trails the flap  26  in the direction of movement  30 . Each minor flap  26  and  28  is foldably attached to its respective end wall  16  by a suitable fold line  32  (only one shown). It will be noted that the minor flaps  26  and  28  are significantly shorter than the length of the major flaps measured along the fold lines  18  and  20  so that in folded position overlying the inner major flap  22  a significant portion of the flap  22  is exposed therebetween. Generally each of the minor flaps will have a width D 2  measured from the fold line  32  to the free edge  29  that does not exceed about ¼ the length of the side wall  14  i.e. the length of the fold line  18  (or  20 ). 
     In the initial position A as shown in FIG. 1 the flaps  22 ,  24 ,  26  and  28  are positioned preferably to extend in substantially vertically in the same plane as the side or end wall to which it is attached so that the flaps project above the side and end walls  14  and  16 . 
     The equipment  12  is provided with a pair of opposed conveyors  34  (preferably similar to those disclosed in the above-referred-to U.S. Pat. No. 5,440,852 issued to Lam, the teaching of which are incorporated herein by reference) that engage opposed side walls  14  and move the carton  10  in straight line path as represented by the arrow(s)  30  through the machine  12 . 
     In the first operation adhesive is applied to the outer face of the inner major flap  22  and to the inside face of the outer major flap  24  in a pattern as will be described below by the adhesive applicators  36  and  38  respectively which are supported by their respective support arm  40  from the cross bar  42 . The flaps  22  and  24  are held in their vertical orientation by suitable guides  44  and  46  respectively (omitted from FIG. 1) each of which is formed by a pair of guide plates  48  and  50  which define a guiding passage substantially parallel to the direction  30  therebetween (See FIG.  2 ). The plates  48  flare away from each other at the entrance end of the passages  52  as indicated at  47  to facilitate entry of the flaps  22  and  24  therebetween. 
     In the first folding operation the inside major flap  22  is folded by an inner major flap folder  53  which includes a shoe  54  mounted on arm  56  and moveable generally by pivoting on an axis substantially parallel to the direction  30  as represented by the arrow  58  in FIG. 2 to contact the flap  22  and fold it over on fold line  18  as will be described below. The leading end of the shoe  54  is flared upward and rearward relative to the direction of travel  30  as indicated at  55  to facilitate entrance of the flap  28  therebeneath as will be described below. 
     When the flap  22  has been folded by shoe  54  the box  10  has reached a position (position C in FIGS. 1 and 2) wherein the two hook like folders (snap folders)  60  and  62  on opposite sides of the path represented by arrow  30  (only one need be used, but the use of two is preferred) are positioned and activated to pivot as indicated by the arrow  64  (for hook  60 ) around substantially vertical axes and fold the trailing or rear minor flap  28  on its fold line  32  over the flap  22  a indicated by the arrow  66  in FIG.  2 . If desired the hook folder may be replaced with a conventional folder  60 A formed by an arm  61  that is swung in from behind the box  10  a velocity higher than the velocity of the box to fold the flap  28  into folded position (see FIG.  5 ). 
     The box  10  is continuously being moved along the path  30  by the conveyors  34  and is moved under a fixed plough  68  which has an upwardly and rearwardly sloping entrance end as indicated at  70  (see FIG. 2) to fold the flap  26  on its fold line  32  over the leading end of the inner major flap  22 . 
     At the same time as the flap  26  is being folded by the plough  68  the trailing minor flap  28  is directed under the shoe  54  by the sloped end  55  of the shoe  54   
     As the box (trailing end wall  16 ) passes the forward toward the leaving or leading end  72  of the plough  68  i.e. while the flaps  26 ,  28  and  22  are being held in folded position by the plough  68  the outer major flap  24  is acted upon by an outer major flap folder  74  that includes a second fixed plough  76  or ski that commences to fold the flap  24  over the flaps  26  and  28  so that the outer major flap  24  engages the adjacent ends of the flaps  26  and  28  to hold them (and flap  22 ) in folded position with the complete folding of the flap  24  being completed when the flap  24  moves to the right of the end  72  of the plough  68 . This the flap  24  is folded on fold line  20  into overlying relation with the flaps  26  and  28  so that the glue or adhesive  37  applied to the inner surface of the flap  24  adheres to the flaps  26  and  28  and holds the flaps  26 ,  28 ,  22  and  24 . 
     The shoe  54  first holds the flaps  22  and  28  in folded relation and then the plough  68  folds the flap  26  over the flap  22  and as the box  10  proceeds it traps the flap  28  therebeneath so that the once the flaps  26 ,  28  and  22  have been folded they are held in folded position by the shoe  54 , the plough  68  and by the outer major flap  24  overlying at least the end edges of the flaps  26  and  28  adjacent to the fold line  20 . Thus the flaps  22 ,  26  and  28  once folded are never free to return to an unfolded position. 
     The conveyors  34  deposit the closed carton  10  in the F position wherein a compression system  80  compresses the carton  10  vertically. In the illustrated arrangement the compression system  80  comprises a pressure plate  82  that is moved vertically as indicated by the arrow  84  to apply pressure to the box  10  moving the adhesive and adjacent panels of the flaps into intimate contact to better ensure the bonding of the closure. 
     The arrangement illustrated in FIG. 1 shows the carton or box  10  stationary in position F, but if desired the compression unit may replace with a compression unit such as that illustrated at  80 A (see FIG.  7 ). In this arrangement a frame  91  mounts a plurality of parallel rows of rollers  92  and the box is made to travel under the rollers  92  which are set at a height as schematically represented by the mounting flange  94  which is used to fix the frame  90  (to the frame of the machine) with the rollers  92  at the desired height. 
     With reference to FIG. 2 the method of the present invention will now be described. In the adhesive application stage position B in FIG. 2 the major flaps  22  and  24  are guided or held in position by the guides  44  and  46  respectively with the top end of the flaps  22  and  24  each received in and passing along its respective passage  48  while the applicators  36  and  38  are in their positions to dispense adhesive in stripes  37  in a specific pattern as shown in FIG.  3 . The pattern leaves an area  90  free of adhesive. The adhesive free area  90  is formed by a longitudinal portion  92  extending the length of the flap  22  between the edge of the flap  22  formed by the fold line  18  and a line spaced therefrom by a distance of between about ⅓ and ⅔ the width D 1 , preferably at least about 40% and less than 60% the width D 1 . In the most preferred embodiment a central adhesive free portion  94  is positioned symmetrically along the longitudinal centerline of the flap  22  from the portion  90  and extends to the free edge  25  of the flap  22 . The length of the portion  94  measured parallel to the free edge  25  is preferably correlated to the width D 2  of the flaps  26  and  28  so that the adhesive only contacts the flaps  26  and  28  when the box  10  is closed. Thus the adhesive is limited to the rectangular areas  96  and  98  outlined by dot dash lines and position one in each outside corner of the flap  22 . 
     The adhesive free area  90  is correlated with the size of the shoe  54  and its movement in contact with the outer face of the flap  22  to ensure the shoe only contacts the flap  22  in the adhesive free area  90 . 
     The adhesive stripes  37  are preferably applied to the inner surface of outer major flap  24  in essentially the same pattern as the adhesive is applied to the flap  22  as then the same control may be used for both applicators  36  and  38 . It will be apparent that the inside of the flap  24  is not contacted by a folder thus the adhesive pattern on the inside of the flap  24  need not leave the same adhesive free space as is provided on the outside of flap  22 . It is preferred that the adhesive only be applied on the flap  24  in areas directly overlying the flaps  26  and  28 . 
     With the adhesive  37  applied the box moves into position C where the shoe  54  is moved as indicated by the arrow  58  to contact the flap  22  in the adhesive free area  90  and slides along the surface of the flap  22  as it folds flap  22  on fold line  18  into a position substantially perpendicular to the side wall  14 . When the flap  22  reaches this position perpendicular to the wall  14  the hook  60  (and  62  if provided) or folder  60 A (FIG. 4) is actuated and the hook  60  moves as indicated by arrow  64  to fold the flap  28  on its fold line  32  as indicated by the arrow  66  into a position perpendicular to the wall  16  and overlying the flap  22  essentially as shown in position D. 
     As the box  10  continues to advance in the direction  30  the leading flared portion  55  of the shoe  54  directs the flap  28  therebeneath to hold the flap  28  in folded position (see FIG.  5 ). As this occurs the leading minor flap  26  is contacted by the leading end  70  of the plough  68  which by continued relative movement of the box  10  and plough  68  folds the flap  26  into a position perpendicular to the wall  16  and overlying the flap  22 . In these positions the adhesive stripes  37  on the outside surface of the flap  22  are brought into contact with the flaps  26  and  28  to secure the flaps  26  and  28  to the inside major flap  22 . As above described the plough  68  holds the flaps  26  and  28  against the inner major flap  22  until the folding of the flap  24  has advanced sufficiently to trap the flaps  26  and  28  and thus hold the flaps  26 ,  28  and  22  folded. Obviously the adhesive on the flap  22  contacting the flaps  26  and  28  help to hold the flaps  26 ,  28  and  22  in their folded positions. 
     As the box  10  clears the edge leading end  72  of the plough  68  the ski or plough  74  completes the folding of the outside major flap  24  over top of the box  10  and brings the adhesive stripes  37  on the inside surface of the flap  24  into contact with the flaps  26  and  28  to secure the outer flap  24  to the flaps  26  and  28 , i.e. the flaps  26  and  28  are sandwiched between and secured to the major flaps  22  and  24  to complete the closing of the box  10  as illustrated in position E. 
     The closed box  10  then moves into the compression station or position F where the compressor  80  or compressor  80 A compress the flaps  22 ,  24 ,  26  and  28  together and may if desired slightly compress the box  10 . 
     It will be apparent that folding plough, particularly the plough  74  could be replaced by other suitable folders, such as a moveable shoe similar to that shown at  54 , provided the timing and positioning of such a shoe results in the leading and trailing minor flaps and the inner major flap are held in position untill the outer major flap is partially folded and is in a position to trap and hold the flaps so folded when released by the plough by plough  68  and folding of the outer flap  24  is completed when the carton  10  has passed (clears) the trailing end  72  of the plough  68 . 
     Having described the invention, modifications will be evident to those skilled in the art without departing from the scope of the invention as defined in the appended claims.