Patent Publication Number: US-6910314-B2

Title: Random automatic case sealer

Description:
This invention relates to box or case sealers for closing the open ends of cardboard boxes or cartons. 
   BACKGROUND OF THE INVENTION 
   In the packaging industry, many products are packed in cardboard boxes or cartons for shipping. Often, one end of the box, namely the bottom, is sealed shut before the box is filled, and after the box is filled, the open top end of the box usually has end and side flaps that are folded inwardly and downwardly. The box can be sealed by applying glue to the inside of the mating surfaces of the folded flaps prior to them being folded shut, or by applying tape to the outside of the flaps after they have been folded shut. 
   In many cases, the boxes are uniform in size, so providing apparatus that will fold the flaps and apply adhesive or tape thereto is not particularly difficult to do. The apparatus can be adjusted to suit the known width and the height of the boxes and there is usually no problem running the boxes through the case sealer once it has been adjusted properly. 
   However, sometimes the boxes are of different sizes coming down the same conveyor line. In these instances, a random case sealer is required, wherein the apparatus for folding the box flaps and applying adhesive or tape thereto adjusts automatically to suit the size of the box. 
   In prior art random case sealers, various sensors have been used to try to determine the exact size or position of the boxes entering the case sealer, and numerous actuators or other adjust mechanisms together with suitable control devices, have been used to adjust the position of the various folding and sealing components to suit the position and size of the box being sealed. A difficulty with this type of apparatus however, is that the boxes are often misshaped or underfilled or overfilled, so that they are not uniform in shape so the sensors often cannot determine the optimum position adjustments. The result is that the boxes get jammed in the apparatus shutting down the packaging line. 
   The jamming problem was largely overcome by the box sealer apparatus described in U.S. Pat. No. 5,685,814 issued to Tuan Vinh Le. In this patent, the folding and sealing components of the apparatus are gravitationally biased and positioned by contact with the actual box being sealed, so any variations in the shape of the box are automatically accommodated. Sometimes, however, the cardboard or box board used to make the cartons is not as thick or strong as it should be, or the boxes are underfilled, in which case the boxes can still be deformed during the sealing operation with undesirable results. 
   SUMMARY OF THE INVENTION 
   In the present invention, the folding and sealing components of the apparatus are positioned by contact with the actual box being sealed, thus accommodating non-uniformity of the boxes, yet the forces on the box components are controlled, so as to avoid the application of excessive force to the boxes. 
   According to the invention, there is provided a case sealer comprising a frame having a longitudinal axis and including an entrance conveyor for moving boxes entering the case sealer along the axis. A pair of longitudinal, spaced-apart, lateral conveyors is located to receive boxes from the entrance conveyor. Linking means are provided for linking the lateral conveyors together for equal movement inwardly and outwardly to match the width of a box passing therethrough. The lateral conveyors include converging centering conveyor belts forming a throat to center a box therebetween, and means actuatable upon a box contacting both centering conveyor belts for moving the lateral conveyors outwardly while maintaining the box in contact with both centering conveyor belts. The lateral conveyors also include parallel first advancing conveyor belts for receiving a box from the centering conveyor belts, and means for urging the lateral conveyors inwardly for engagement of the first advancing conveyor belts with the box. A floating head is spaced above the lateral conveyors, the floating head including an upwardly inclined entry ramp adapted to engage and fold inwardly a forward end flap on a box. Means are provided for lifting the floating head upwardly. The entry ramp includes a sensor switch operatively connected to the means for lifting the floating head upwardly, the switch being activated to raise the floating head upon a top horizontal edge of the box engaging the inclined entry ramp, and deactivated when the floating head is clear of the top of the box. The floating head includes a pivoting arm assembly including a pivot arm pivotable downwardly after the box passes thereunder to fold inwardly a rearward end flap on the box. The floating head further includes diverging side bars for engaging and folding inwardly side flaps on the box after the rearward end flap has been folded inwardly. A seal dispensing platform is located downstream of the first advancing conveyor belts. The seal dispensing platform includes means for holding box flaps shut and means for locating the holding means adjacent to the box flaps. The seal dispensing platform is adapted to mount a seal dispenser centrally thereon for sealing the box flaps shut. The seal dispensing platform includes spaced-apart, parallel second advancing conveyors located to receive boxes from the first advancing conveyor belts, and means for urging the second advancing conveyors into engagement with a box for passing the box under the seal dispenser platform and out of the case sealer. 

   
     BRIEF DESCRIPTION OF THE FIGURES 
     Preferred embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: 
       FIG. 1  is a perspective view taken from above and from the entrance end of a preferred embodiment of a case sealer according to the present invention; 
       FIG. 2  is a perspective view similar to  FIG. 1  but taken from a higher and more rearward angle and with some parts omitted for the purposes of clarity; 
       FIG. 3  is an enlarged perspective view of a portion of the entrance conveyor of the case sealer of  FIGS. 1 and 2 ; 
       FIG. 4  is a perspective view taken from above and from the rear showing some of the components of the case sealer shown in  FIGS. 1 and 2 ; 
       FIG. 5  is a perspective view taken from below of the lateral conveyors shown in  FIGS. 1 and 2 ; 
       FIG. 6  is a perspective view taken from below of the tape dispensing platform shown in  FIGS. 1 and 2 ; 
       FIG. 7  is a side elevational view taken along lines  7 — 7  of  FIG. 1 ; 
       FIG. 8  is a side elevational view similar to  FIG. 7  but showing a second preferred embodiment of the present invention having only one floating head; 
       FIG. 9  is a sectional view taken along lines  9 — 9  of  FIG. 3 ; and 
       FIG. 10  is a sectional view taken along lines  10 — 10  of FIG.  3 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to the drawings, a preferred embodiment of a case sealer according to the present invention is generally indicated in the drawings by reference numeral  10 . Case sealer  10  includes a frame  12  mounted on castors  14 , so that the case sealer is easily transportable or movable from one packaging line to another. Retractable feet  16  are threadably mounted in frame  12  to engage the floor and make case sealer stationary, if desired. Frame  12  has a longitudinal axis  18  which indicates the direction in which boxes or cartons or cases travel to be closed and sealed shut in case sealer  10 . 
   Case sealer  10  is normally located adjacent to a packaging line (not shown) to close and seal, one at a time, filled boxes received from such a packaging line. However, boxes or cartons could be manually placed on case sealer  10  if desired. Where the cases are received from a packaging line, a gate mechanism  20  can be provided to space the cases apart prior to being closed and sealed, as will be described further below. However, the gate mechanism could be provided on the end of the packaging line rather than on case sealer  10 , if desired. 
   Case sealer  10  includes an entrance conveyor  22  which has a plurality of spaced-apart, longitudinal endless conveyor chains or belts  24 . Conveyor chains  24  extend the full length of case sealer  10 . Chains  24  are driven by a motor  26  and gear box  28  driving another drive chain  30 , which in turn rotates a shaft  32  having a sprocket  34  mounted thereon. Shaft  32  has additional sprockets  34  to drive each of the continuous chains  24 . Chains  24  operate at speeds typically between about 15 to 25 meters per minute. 
   Entrance conveyor  22  also includes a plurality of rollers  36  located between conveyor chains  24  to support the boxes thereon. Rollers  36  are driven by chains  24  using suitable sprockets attached thereto or to the shafts  37  on which the rollers are mounted. 
   Pushers  46  can either be biased by gravity to lie down or springs (not shown) could be used for this purpose. The pushers that were upright also move laterally under the force of springs  62 , so that they will not pop upright unless they are forced to do so at the appropriate time by cam  52 . When pushers  46  reach the ends of tracks  38 , tabs  53  come out of grooves  42  and the pushers then lie down again until they come around by the return of chains  24  and again engage cams  52 . 
   With reference to FIGS.  3 , 9  and  10  it will be seen that coveyor chains  24  travel along tracks  38  which extend longtitudinally along the length of case sealer  10 . Tracks  38  have a pair of longitudinal grooves  40 , 42  formed therein. Grooves  40  have a widened portion or shelf  44  located at the ends of tracks  38  adjacent to the entrance of case sealer  10 . Conveyor chains  24  pushers  46  pivotally mounted thereon. Only three pushes  46  are shown in  FIG. 3  for the purposes of clarity, but the pushers  46  are spaced longitudinally all along the chains  24  at intervals of about 8 to 12 centimetres. Pushers  46  stand up to push a box through case sealer  10 , but when they lie down they have downwardly depending legs  48  and  50  on either side of chains  24 . When pushers  46  are lying down, the legs  50  normally travel along in respective grooves  40 , and legs  48  normally travel oover the top edge  51  forms a sidewall of groove  42 . However, when it is desired to have pushers  46  stand up to engage a box, a cam  52  is moved inwardly causing a tab  53  on leg  48  to engage cam  52  and move pusher  46  transversely or sideways. This causes leg  50  to move sideways and engage another cam  54 , which is actually one of the side walls of groove  40 . This cause the pusher  46  to tilt upwardly into an upright position so that it can engage a box to be pushed through case sealer  10 . Tabs  53  ride along in groove  42  to keep pushers  46  upright. 
   According to the invention, there is provided a case sealer comprising a frame having a longitudinal axis and including an entrance conveyor for moving boxes entering the case sealer along the axis. A pair of longitudinal, spaced-apart, lateral conveyors is located to receive boxes from the entrance conveyor. Linking means are provided for linking the lateral conveyors together for equal movement inwardly and outwardly to match the width of a box passing therethrough. The lateral conveyors include converging centering conveyor belts forming a throat to center a box therebetween, and means actuatable upon a box contacting both centering conveyor belts for moving the lateral conveyors outwardly while maintaining the box in contact with both centering conveyor belts. The lateral conveyors also include parallel first advancing conveyor belts for receiving a box from the centering conveyor belts, and means for urging the lateral conveyors inwardly for engagement of the first advancing conveyor belts with the box. A floating head is spaced above the lateral conveyors, the floating head including an upwardly inclined entry ramp adapted to engage and fold inwardly a forward end flap on a box. Means are provided for lifting the floating head upwardly. The entry ramp includes a sensor switch operatively connected to the means for lifting the floating head upwardly, the switch being activated to raise the floating head upon a top horizontal edge of the box engaging the inclined entry ramp, and deactivated when the floating head is clear of the top of the box. The floating head includes a pivoting arm assembly including a pivot arm pivotable downwardly after the box passes thereunder to fold inwardly a rearward end flap on the box. The floating head further includes diverging side bars for engaging and folding inwardly side flaps on the box after the rearward end flap has been folded inwardly. A seal dispensing platform is located downstream of the first advancing conveyor belts. The seal dispensing platform includes means for holding box flaps shut and means for locating the holding means adjacent to the box flaps. The seal dispensing platform is adapted to mount a seal dispenser centrally thereon for sealing the box flaps shut. The seal dispensing platform includes spaced-apart, parallel second advancing conveyors located to receive boxes from the first advancing conveyor belts, and means for urging the second advancing conveyors into engagement with a box for passing the box under the seal dispenser platform and out of the case sealer. 
   Referring next to  FIGS. 4 and 5 , lateral conveyors  58  and  60  are slidably mounted on transverse shafts  62  and  64  for inward and outward movement to adjust for the width of a box being sealed in case sealer  10 . Lateral conveyors  58  and  60  are linked together for equal movement inwardly and outwardly to match the width of the box passing therethrough. The linking means includes a pair of belts  66  and  68  (see FIG.  5 ). Each belt has one respective end  70 ,  72  attached to a slide mount  74  which slidably mounts lateral conveyor  60  on shaft  62 . Each of the belts  66  and  68  has a second opposed respective end  76 ,  78  attached to a second slide mount  80  which slidably mounts lateral conveyor  58  on shaft  62 . Sheaves  82  and  84  are rotatably mounted in frame  12 , so that belt  66  passes around sheave  82  and belt  68  passes around sheave  84 , as a result, when slide mount  80  moves outwardly away from the longitudinal center line of case sealer  10 , belt  66  causes slide mount  74  also to move outwardly away from the longitudinal center line of case sealer  10 . Similarly, when slide mount  74  moves inwardly towards the center line of case sealer  10 , belt  68  causes slide mount  74  to move inwardly towards the center line of the case sealer. Slide mount  74  is moved inwardly and outwardly by a pneumatic cylinder  86  mounted in frame  12  and acting through a spring mount  88  attached to slide mount  80 . Spring mount  88  provides some flexibility for the relative positioning of lateral conveyors  58  and  60  to accommodate some non-uniformity in the width of the boxes being sealed in case sealer  10 . The belts  66  and  68  pass around sheaves  82  and  84  in a U-shaped fashion. Chains and sprockets could be used in place of belts and sheaves. Other devices, such as racks and a pinion could also be used to link the lateral conveyors together, so that outward and inward movement of one lateral conveyor causes respective outward and inward movement of the other lateral conveyor. 
   Lateral conveyors  58  and  60  have diverging centering conveyor belts  90  and  92  forming a throat  94  to center a box therebetween. As seen best in  FIG. 1 , if a box travelling toward lateral conveyors  58  and  60  is off center, it will hit one of the centering conveyor belts  90  and  92  first, and this centering conveyor belt will move the box over toward the center. 
   Lateral conveyors  58  and  60  also have centering sensors  96  and  98  mounted just above their respective centering conveyor belts  90  and  92 . Centering sensors  96  and  98  are pivotably mounted bars that actuate limit switches behind them. When a corner of the box hits one of the centering sensors  96  or  98 , the sensor retracts closing its limit switch while still allowing the box to engage the respective centering conveyor belt  90  or  92 . This causes the box to be moved over toward the center of the case sealer. When both the centering sensors  96  and  98  are engaged by the box, the box is centered. The respective limit switches in sensors  96  and  98  are connected in series and when both switches are closed, this causes a controller to actuate cylinder  86  and cause the lateral conveyors  58  and  60  to open up to accommodate the box. Cylinder  86  acts slowly enough to ensure that both corners of the advancing box remain in contact with centering conveyor belts  90  and  92  and the speed of centering conveyor belts  90  and  92  is higher than entrance conveyor  22  so that the boxes advance at the same speed as the pushers  46  are moving along entrance conveyor  22 . 
   The box continues to advance until the leading vertical corners of the box engage a pair of parallel, first advancing conveyor belts  100  and  102  mounted in the respective lateral conveyors  58  and  60 . As this happens, the box trips another limit switch  104  (see  FIG. 7 ) causing the controller to close the control valve controlling cylinder  86  to lock the first advancing conveying belts  100  and  102  in engagement with the box therebetween. The first advancing conveyor belts  100  and  102  then continue at the same speed as entrance conveyor  22  to move the box through case sealer  10  until the leading top flap of the box engages a 45 degree upwardly inclined entry ramp  106  mounted in a first floating head  108  spaced above the lateral conveyors  58  and  60 . Entry ramp  106  includes a sensor bar  110 . When the top horizontal edge of the box hits sensor bar  110 , this causes a controller to actuate another pneumatic cylinder  112  and raise floating head  108  upwardly at a speed such that top horizontal edge of the box remains in contact with entry ramp  106 . As the top flap of the box is folded downwardly and the top of the box passes under sensor bar  110 , its limit switch opens causing the control valve operating cylinder  112  to close locking the floating head  108  in position. In this way, floating head  108  rises filled. As the box advances further, upwardly and outwardly disposed side bars  114  and  116  engage the box side flaps and fold them inwardly. Before the box side flaps are folded down, however, the trailing end flap of the box is folded downwardly by a pivot arm  118  actuated by another pneumatic cylinder  120 . Pivot arm  118  can be activated by limit switch  104 . 
   Pivot arm  118  and pneumatic cylinder  120  are part of a pivot arm assembly  122  slidably mounted in a boom  124  mounted in floating head  108 . Pivot arm assembly  122  is moved along boom  124  by another pneumatic cylinder  126  to accommodate and close the trailing end flaps of boxes of varying lengths up to about 2 meters or even longer simply by making boom  124  and entrance conveyor  122  longer, as required. Where such long boxes are sealed in case sealer  10 , the position of the pivot arm assembly and the activation of the pivot arm  118  is controlled by the limit switch  56  which senses when the trailing end wall of the box has entered the entrance conveyor  22 . 
   Floating head  108  includes a transverse member  128  attached at its opposed distal ends to slides  130  mounted for vertical sliding movement on shafts  132  in towers  134 . Cylinders  112  mounted in towers  134  are connected to slides  130  to move the floating head  108  up and down, as mentioned above. Towers  134  further include counterweight devices  136  attached to slides  130  to offset the weight of floating head  108 . Counterweight devices  136  could be gravitational devices or coil spring type devices, as desired. 
   As the box passes out through the lateral conveyors  58 ,  60  and while the box top flaps are still being held down by floating head  108 , the top, leading horizontal edge of the box engages a pair of entry ramps  138  and  140  mounted in a second floating head  142 . Entry ramps  138  and  140  are also inclined at an angle of 45 degrees, like ramp  106 . Floating head  142  is similar to floating head  108  in that it has a transverse member  144  having opposed ends attached to slides  130  slidably mounted on shafts  132  in towers  146  with pneumatic cylinders  148  to move the floating head up and down and counterweight devices  150  to offset the weight of the floating head  142 . Cylinders  148  are attached to slides  130  through spring mounts  151  to provide some flexibility for the relative positioning of floating head  142  and to accommodate some non-uniformity in the height of the boxes (up to 10 centimeters) such as may be caused by overfilling, for example. Entry ramps  138  and  140  themselves have conveyor belts  152  and  154  mounted thereon, and one of the entry ramps includes a sensor bar  156  which operates a limit switch connected to cylinder  148  through an appropriate controller and actuator valve device to raise second floating head  142  at a speed to maintain the box in contact with entry ramps  138 ,  140 . When the floating head  142  is raised sufficiently to allow the box to pass under ramps  138 ,  140 , the sensor bar  156  stops the vertical movement of the second floating head  142  and the box passes under a seal dispensing platform  158 . Again, this allows over filled boxes to be accommodated. Seal dispensing platform  158  is located downstream of the first advancing conveyor belts  100 ,  102  of the first floating head  108 , and the seal dispensing platform  158  is means for holding the box flaps shut until they are sealed by a sealing device such a tape machine or dispenser  160  mounted on seal dispenser platform  158 .  FIG. 1  shows a taping machine  160  where the tape supply  161  is mounted on the taping head. However, it is preferable to have the tape supply mounted separately on frame  12 , as shown in FIG.  8 . In any event, any type of tape dispenser  160  could be used in the subject invention. 
   As the box passes under seal dispensing platform  158 , it engages another limit switch  162  which causes seal dispensing platform  158  to move downwardly to apply pressure to the top of the box and also cause the spaced-apart, parallel, second advancing conveyors  164  and  166  to move inwardly to engage the sides of the box. Conveyors  164  and  166  preferably are formed of free wheeling rollers  170  as indicated in FIG.  6 . Further advance of the box causes it to hit another limit switch  163  to lock seal dispensing platform  158  in position. 
   Second advancing conveyors  164 ,  166  are linked together by linking belts  172 ,  174  (see  FIG. 6 ) in a manner similar to the belts  66  and  68  of the lateral conveyors  58  and  60 . In this way, the second advancing conveyors  164  and  166  move inwardly and outwardly simultaneously using only one actuating cylinder  176  acting through a spring mount  175 . One of the second advancing conveyors  164 ,  166  has a sensor bar  177  to sense when the sides of the box are engaged by conveyors  164  and  166 , control the pressure of conveyors  164  and  166  on the box, and lock conveyors  164  and  166  in position. When the box passes the second floating head  142  and tape dispenser  160 , sensor  179  (see  FIG. 7 ) senses this and allows conveyors  164  and  166  to open again and floating head  142  to rise to be ready for the next box to be sealed. 
   In the operation of case sealer  10 , the case sealer can be made to operate in several different modes as selected by a control box  178 . Where the boxes are all of the same height, width and length, the gate mechanism  20  can be opened at regular intervals almost as soon as the rear wall of a box ahead passes limit switch  56 . This will provide a gap or spacing between the boxes of about 25 to 35 centimeters. The speed of entrance conveyor  22  and lateral conveyors  58  and  60  is such that the first box will clear the lateral conveyors  58  and  60  so that they return to their starting position before the next box engages the centering conveyor belts  90  and  92 . Lateral conveyors  58  and  60  return inwardly to their starting position when a limit switch  180  (see  FIG. 7 ) senses that the box between them has cleared the lateral conveyors  58  and  60 . Alternatively, lateral conveyors  58  and  60  can stay in their existing position, because the next box is of the same width. The box can go on to be sealed by the floating sealing head  142  while another box is entering lateral conveyors  58  and  60  to have its flaps folded down by floating head 
   In a second mode of operation where the height and width of the boxes are the same but the lengths of the boxes vary, the cylinder  126  moves the pivot arm assembly  122  out to the end of boom  124 , and as soon as the rear end of the box is sensed passing limit switch  56 , cylinder  126  retracts the pivot arm assembly  122 , so that pivot arm  118  travels along at the same speed as the box. Just prior to the box side flaps being folded down on top of the box front flap by side bars  114 ,  116 , pivot arm  118  comes down to close the back flay of the box. This could be triggered by the box hitting limit switch  104 . Limit switch  56  also causes the pushers  46  to pop up behind the box, as mentioned above. 
   In a third mode of operation where the boxes vary in length, width and height between about 15 and 60 centimeters, the pivot arm assembly  122  stays in its inward or retracted position, but the gate mechanism  20  is not lowered to let the next box enter the case sealer until the previous box has passed limit switch  104 . Limit switch  104  can also be used to activate pivot arm  118 . This allows the first floating head station and lateral convevors  58  and  60  to be reset to accept the next randomly sized box. 
   In a fourth mode of operation, where the boxes vary in width and heights and also in length between about 50 centimeters and about 1.5 meters, the pivot arm assembly  122  extends to the outer end of boom  124  and retracts with the box as in the second mode above. When the front of the box hits limit switch  104 , pivot arm  118  comes down to close the rear box flag. However, when the rear end wall of the box passes limit switch  56 , the gate mechanism  20  does not open again until the rear of the box has passed limit switch  104 . 
   Referring next to  FIG. 8 , another preferred embodiment of a case sealer  182  is shown. The same reference numerals have been used in  FIG. 8  to indicate components that are essentially the same as those of the embodiments shown in  FIGS. 1-7 . In the  FIG. 8  embodiment, the second floating head has been eliminated and the seal dispensing platform  184  that corresponds to  FIG. 6  has been attached to the first floating head  108  by attachment members  186 . Case sealer  182  is also shown having a preferred type of taping machine  188  where the supply of tape  190  is located above the seal dispensing platform  184 . A pivoting tension bar  191  with an adjustable counterweight  192  maintains tension in the tape  194  even though the tape machine  188  is moving up and down. Case sealer  182  works in a maimer similar to case sealer  10  but the box being sealed has to clear the seal dispensing platform  184  before the lateral conveyors  58  and  60  can be reset to accept the next box to be sealed. 
   Having described preferred embodiments of the invention, it will be appreciated that various modifications may be made to the structures described above. For example, instead of using pneumatic cylinders to control the various components of the case sealers, it will be appreciated that hydraulic devices or electric motors or solenoids could be used as well. Programmable logic controllers are preferred for controlling the various components of the case sealers, but other types of controls could be used as well, such as simple timers. Limit switches have been described as the preferred position sensors, but other devices such as photoelectric, infrared or other motion sensors or proximity sensors could be used as well. 
   As will be apparent to those skilled in the art in light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof. Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims.