Abstract:
A method of applying adhesive to major and minor flaps of a container in a siftproof adhesive pattern. A pair of adhesive dispensing guns are moved with respect to the flaps of the container as the container is conveyed past the guns. Electric actuators, such as linear modules or rotatable servo modules, are used to rapidly accelerate the guns in a direction perpendicular to the path of the container along a conveyor. In this manner, rapid packaging takes place and reliable siftproof patterns are achieved using minimal adhesive.

Description:
[0001]     This application is a divisional of application Ser. No. 10/279,600 filed on Oct. 24, 2002 (pending) which is a continuation-in-part of application Ser. No. 09/702,430 filed Oct. 31, 2000 (now U.S. Pat. No. 6,586,050), the disclosures of which are fully incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention generally relates to apparatus and methods for sealing containers and, more specifically, to apparatus and methods of sealing containers in a siftproof manner designed to prevent leakage of particulate contents or infestation by insects.  
       BACKGROUND OF THE INVENTION  
       [0003]     Many containers, such as cartons, boxes or other less rigid containers, are constructed from paper-based materials and include open ends each having a plurality of flaps. Typically, the flaps at each end include a pair of opposed major flaps and a pair of opposed minor flaps. The containers are usually folded from a flat condition into an erected condition, after which a desired product may be introduced into the container. The flaps are then folded and connected together, typically using an adhesive, to close the opposite ends of the container. The minor flaps are folded down first and the major flaps are folded down next and sealed to upper surfaces of the minor flaps using adhesive.  
         [0004]     Particulate products, such as granulated or powdered products, require packaging that prevents leakage of the product during shipment and storage. Plastic liners may be used inside the container for this purpose, however, such liners increase packaging costs. To reduce costs, linerless siftproof containers and sealing methods have been developed for storing and shipping particulate products. The end flaps of these siftproof containers must be tightly sealed in a manner that prevents the contents from sifting out between the flaps and which likewise prevents infestation by insects through gaps between the flaps. In the past, all of the flaps have received adhesive deposits in the form of intermittent or continuous adhesive beads to ensure that the seams between the various flaps are sealed in a siftproof manner.  
         [0005]     As the development of siftproof containers has progressed, certain problems have been addressed relative to siftproof seal integrity and costs associated with the adhesive and the paper construction products. For example, embossments have been used on the various flaps to provide opposed surfaces lying in close relation such that the gap between the flaps does not need to be filled with as much adhesive. Other siftproof containers have been configured to include a modified first major flap that enables direct contact between embossed portions of the minor flaps and a corresponding embossed portion of the second major flap. While these improvements have helped in some regards, modifying containers in these manners can also add expense and some containers cannot have embossed or otherwise modified flaps.  
         [0006]     Other problems in this art relate to the need for a large of number of adhesive dispensers, or adhesive dispensing nozzles, necessary to place the corresponding number of beads on the container flaps extending in the conveying path of the containers. The increased complexity of the dispensing system increases costs and complicates changeover procedures. In this latter regard, for containers of different configurations and/or sizes, dispensing guns must be removed or added, or nozzles must be removed and plugged or added to accommodate the new configuration or container size.  
         [0007]     Despite the various developments in the area of siftproof containers, improvements are still needed to maintain siftproof seal integrity while reducing adhesive requirements and general manufacturing costs. In this regard, the use of continuous adhesive sealing beads as opposed to a number of intermittent short and long beads only extending parallel to the conveying path requires much less adhesive and lower manufacturing equipment and changeover costs due to the lower number of necessary adhesive guns. However, applying a continuous adhesive bead in a direction generally perpendicular to the conveying path during high-speed packaging operations has been a troublesome problem. Many packaging lines are designed to move at a rate of approximately 400-500 ft./min. or above and, at these high speeds, applying accurate beads of adhesive perpendicular to the direction of the conveying path has been a problem inadequately addressed by prior siftproof packaging systems. With the prior art high-speed siftproof packaging methods, beads of adhesive have been applied only in the direction of the conveying path in order to deal with this problem. This results in the use of much more adhesive than necessary to create a siftproof pattern and necessitates the use of multiple side-by-side adhesive dispensing guns and/or nozzles mounted adjacent the conveying path.  
         [0008]     To solve these and other problems in the art, it would be desirable to provide a method of applying a siftproof pattern of adhesive to the major and minor flaps of a container while using less adhesive and a lower number of adhesive dispensing components while still maintaining a high production rate in a high speed packaging operation.  
       SUMMARY OF THE INVENTION  
       [0009]     The present invention provides an apparatus and method for applying adhesive to respective first and second major flaps and first and second minor flaps of a container in a siftproof pattern. The container is moved along a conveying path with the major flaps being folded in an outwardly extending position. While the container moves along the conveying path, first and second adhesive dispensing guns are moved relative to the container while dispensing beads of adhesive therefrom along respective edges of the major and minor flaps proximate leading and trailing edges of the container and in directions generally perpendicular to the conveying path. These perpendicular beads may be applied starting on the outer edges of major flaps and moving inboard toward the minor flaps or vice versa. In one exemplary embodiment, the perpendicular beads are applied to the flaps of the container by guns which are mounted for pivotal movement about axes oriented generally parallel to the conveying path. In another exemplary embodiment, the first and second guns are simultaneously movable along directions parallel and perpendicular to the conveying path to dispense the adhesive beads to the flaps. In this embodiment, the first and second guns are positioned above a container and move synchronously with the container in a direction parallel to the conveyor path, while dispensing adhesive, so that the location and orientation of the beads may be more precisely controlled.  
         [0010]     In yet another exemplary embodiment, the first and second guns are moveable along a linear path which is oblique with respect to the conveyor path. Advantageously, the speed of the first and second guns along the oblique path may be controlled so that the first and second guns are positioned over a container and move synchronously with the container moving along the conveyor, whereby the orientation and location of the beads applied to the flaps may be more precisely controlled.  
         [0011]     The apparatus further includes a third, stationary adhesive dispensing gun positioned to dispense a bead of adhesive to an outboard edge of one of the major flaps, along a direction parallel to the conveyor path as the container is moved along the conveyor beneath the third gun. This parallel bead is dispensed between, and adjoins, respective perpendicular beads which were dispensed along portions of the major flap corresponding to the leading and trailing edges of the container. The major flaps are then folded and sealed to the minor flaps by folding the first major flap onto the minor flaps and then folding the second major flap onto the first major flap.  
         [0012]     The first and second guns are turned on and off at specific intervals so that the perpendicular beads are only applied to the desired portions of the major and minor flaps. Quick movements of the first and second guns perpendicular to the direction of the conveying path will result in the necessary generally perpendicular beads of adhesive at opposite ends of the major and minor flaps. Electric gun movers, such as linear actuators or servomotors with rotatable outputs, may be used to facilitate quick transverse movement relative to the conveying path. Even with the speed of the container along the conveying path reaching 400-500 ft./min. or above, the adhesive beads necessary in the direction generally perpendicular to the conveying path may be made, while the longer sealing bead extending in the direction of the conveying path is easily placed by the stationary third gun.  
         [0013]     These and other objects, advantages, and features of the invention will become more readily apparent to those of ordinary skill in the art upon review of the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the invention.  
         [0015]      FIG. 1  is a partial perspective view schematically illustrating an adhesive dispensing system in accordance with one aspect of the present invention for applying a siftproof adhesive pattern to a container;  
         [0016]      FIG. 2  is a top plan view of the container shown in  FIG. 1 , illustrating a siftproof pattern in accordance with one embodiment of the present invention;  
         [0017]      FIG. 3  is a perspective view illustrating an adhesive dispensing system in accordance with a second aspect of the present invention;  
         [0018]      FIG. 4  is a perspective view illustrating an adhesive dispensing system in accordance with a third aspect of the present invention;  
         [0019]      FIGS. 5-8  show a plan view of an adhesive dispensing system in accordance with a fourth aspect of the present invention;  
         [0020]      FIGS. 9-1   2  depict an alternate embodiment of the adhesive dispensing system of  FIGS. 5-8 ;  
         [0021]      FIG. 13  is a perspective view illustrating an adhesive dispensing system in accordance with a fifth aspect of the present invention;  
         [0022]      FIG. 14  is a plan view of an adhesive dispensing system in accordance with a sixth aspect of the present invention; and  
         [0023]      FIG. 15  is a perspective view illustrating an adhesive dispensing system in accordance with a seventh aspect of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0024]     Referring to  FIGS. 1 and 2 , an adhesive dispensing apparatus  10  is illustrated for applying adhesive siftproof pattern to a container  12 . The container  12  travels along a conveyor  14  along a path indicated by a directional arrow  16 . The conveyor  14  is schematically illustrated as a belt, however, in practice, such conveyors may take many different forms depending on the packaging operation and the container requirements. As shown more specifically in  FIG. 2 , the container  12  includes a first major flap  20 , a second major flap  22 , a first minor flap  24  and a second minor flap  26 . The minor flaps  24 ,  26  are folded inwardly toward an interior  28  of the container  12 , while the major flaps  20 ,  22  are folded outwardly with respect to the container interior  28 . In this configuration, the container  1   2  is prepared for receipt of the siftproof adhesive bead pattern to be discussed below.  
         [0025]     As shown in  FIG. 1 , the apparatus  10  includes a first support  30  having vertical support members  32  coupled to a horizontal support member  34 . First and second adhesive dispensing guns  36 ,  38  are pivotally mounted to the horizontal member  34  and are coupled to motors  40 ,  42  which operate to pivot the adhesive dispensing guns  36 ,  38  about axes  44 ,  46  which are parallel to the conveying direction  16 . Motors  40 ,  42  and other motors described herein may be servomotors, stepper motors, or any other type of motor which can be operated to control the motion of the adhesive dispensing guns. The first and second adhesive dispensing guns  36 ,  38  are configured to dispense adhesive from respective nozzles  48 ,  50  in an on/off fashion and are mounted to respective manifolds  52 ,  54 . The adhesive dispensing guns  36 ,  38  can be pneumatic guns such as the H200 or H400 Series dispensing guns commercially available from Nordson Corporation of Westlake, Ohio, or electric guns, such as the Nordson® E350 Series. However, other types of pneumatically or electrically-actuated on/off type guns may be used as well. Adhesive is carried to the guns  36 ,  38  through their respective manifolds  52 ,  54  which are in fluid communication with adhesive supply hoses  56 ,  58 . A pair of pressurized air hoses  60 ,  62  feed air to the manifolds  52 ,  54 . The air is supplied through the manifolds  52 ,  54  to the guns  36 ,  38  in order to actuate the guns  36 ,  38  between on and off conditions.  
         [0026]     When the guns  36 ,  38  are on, or in open positions, pressurized adhesive will flow through the hoses  56 ,  58 , manifolds  52 ,  54 , and nozzles  48 ,  50  and are applied to the container  12  to form the siftproof adhesive sealing beads of the present invention. With reference to  FIG. 2 , the siftproof adhesive pattern includes four adhesive bead sections  70 ,  72 ,  74 ,  76  that extend along directions which are substantially perpendicular to the conveying direction  16  and one adhesive bead section  78  that extends along a direction which is substantially parallel to the conveying direction  16 . First and second perpendicular adhesive beads  70 ,  72  extend along first side edges  80 ,  82  of the first and second major flaps  20 ,  22  and along portions of a folded edge  84  of the first minor flap  24 . Similarly, the third and fourth perpendicular adhesive beads  74 ,  76  extend along second side edges  86 ,  88  of the first and second major flaps  20 ,  22  and along portions of the folded edge  90  of the second minor flap  26 . The parallel adhesive bead  78  extends along the free edge  92  of the second major flap  22  and joins with end portions  94 ,  96  of the second and fourth perpendicular adhesive beads  72 ,  76  to form a continuous length of adhesive bead having a generally C shape.  
         [0027]     With continued reference to  FIGS. 1 and 2 , operation of the adhesive dispensing system  10  to create the siftproof adhesive pattern shown in  FIG. 2  will now be described. The container  12  is moved along the conveyor  14  generally in the direction of the arrow  16 . As the leading edge  98  of the container  12  passes beneath the first and second adhesive dispensing guns  36 ,  38 , the motors  40 ,  42  are actuated to pivot the adhesive dispensing guns  36 ,  38  about their axes  44 ,  46  while the guns  36 ,  38  are turned on to dispense the first and second perpendicular adhesive beads  70 ,  72 . The motors  40 ,  42  may move the guns  36 ,  38  such that the nozzles  48 ,  50  dispense the adhesive beads  70 ,  72  in directions either from inboard of the container  12  to the outboard edge, or vice versa, such that the first and second perpendicular beads  70 ,  72  are laid approximately at locations  100  to  102  and  104  to  94 , respectively, as the container  12  continues to advance along the conveyor  14 . After the first and second adhesive beads  70 ,  72  have been applied to the container  12 , the first and second adhesive dispensing guns  36 ,  38  are turned off. When the trailing edge  106  of the container  12  passes beneath the first and second adhesive dispensing guns  36 ,  38 , the guns  36 ,  38  are turned on again and the motors  40 ,  42  are actuated to pivot the first and second adhesive dispensing guns  36 ,  38  to apply the third and fourth perpendicular adhesive beads  74 ,  76  in a manner similar to that described above for the first and second adhesive dispensing beads  70 ,  72 . After the third and fourth perpendicular adhesive beads  74 ,  76  have been applied to the container  12 , the first and second adhesive dispensing guns  36 ,  38  are turned off again.  
         [0028]     While the operation of adhesive dispensing guns  36 ,  38  is described and illustrated herein as being turned on and off to dispense the perpendicular adhesive beads  70 ,  72  and  74 ,  76  simultaneously, it will be recognized that these, and other adhesive dispensing guns described herein, may be configured to turn on and off at different times instead. For example, one gun may be positioned upstream or downstream of the other.  
         [0029]     The container  12  continues to advance along the conveyor  14  and the second major flap  22  passes beneath a third adhesive dispensing gun  108  mounted to a second support  110 , located downstream of the first and second guns  36 ,  38 . The third adhesive dispensing gun  108  includes a nozzle  112  and is coupled to an adhesive supply hose  114  and an air hose  116  for operation in a manner similar to first and second adhesive dispensing guns  36  and  38 . As the leading edge  98  of the container passes beneath the third adhesive dispensing gun  108 , the third gun  108  is turned on to dispense the parallel adhesive bead  78  along the free edge  92  of the second major flap  22  and between the second and fourth perpendicular adhesive beads  72 ,  76 . As the trailing edge  106  passes beneath the third adhesive dispensing gun  108 , the third gun  108  is turned off.  
         [0030]      FIG. 3  depicts an alternative exemplary embodiment of an apparatus  10   a  for applying the siftproof pattern of adhesive according to the present invention. In the alternative embodiments hereinafter described, elements which are similar to those described above with respect to  FIGS. 1 and 2  are similarly numbered. In the embodiment shown in  FIG. 3 , the first and second adhesive dispensing guns  36   a ,  38   a  are mounted to pivot about a common axis  120  by extension arms  122 . A single motor  124  is used to rotate the first and second adhesive dispensing guns  36   a ,  38   a  about the axis  120  to thereby apply the first, second, third and fourth perpendicular adhesive beads  70 ,  72 ,  74 ,  76 . Specifically, as the leading edge of the container  98  passes beneath the first and second adhesive dispensing guns  36   a ,  38   a , the motor  124  is actuated to move the adhesive dispensing guns  36   a ,  38   a  in either a clockwise or counterclockwise direction to dispense the first and second perpendicular adhesive beads  70 ,  72  while the container  12  continues to travel along the conveyor  14 . After the first and second adhesive beads  70 ,  72  have been applied to the container flaps  20 ,  22 ,  24 , the first and second adhesive dispensing guns  36   a ,  38   a  are turned off. As the trailing edge  106  of the container  12  passes beneath the first and second adhesive dispensing guns  36   a ,  38   a , the first and second guns  36   a ,  38   a  are turned on again and the motor  124  is actuated to rotate the first and second guns  36   a ,  38   a  about the axis  120  to apply the third and fourth perpendicular beads  74 ,  76  along the side edges  86 ,  88  of the first and second major flaps  20 ,  22  and portions of the folded edge  90  of the second minor flap  26 . The first and second adhesive dispensing guns  36   a ,  38   a  are turned off again and the container  12  continues to advance along the conveyor  14 . As the leading edge  98  of the container  12  passes beneath the third adhesive dispensing gun  108 , the third gun  108  is turned on and applies the parallel adhesive bead  78  to the free edge  92  of the second major flap  22  as the container  12  travels along the conveyor  14 . As the trailing edge  106  of the container  12  passes beneath the third adhesive dispensing gun  108 , the gun  108  is turned off to complete the siftproof pattern.  
         [0031]      FIG. 4  illustrates yet another exemplary adhesive dispensing apparatus  10   b  for applying the siftproof pattern of the present invention. In this embodiment, the first and second adhesive dispensing guns  36   b ,  38   b  are suspended beneath the horizontal support member  34   b  from support rods  126  which are pivotally connected to the horizontal support member  34   b . A motor  128  and crank linkage  130  are coupled to the ends of the support rods  126  whereby the motor  128  may cause the first and second adhesive dispensing guns  36   b ,  38   b  to pivot about their joints  132  to move transversely across the conveyor direction  16 . In this manner, the first and second adhesive dispensing guns  36   b ,  38   b  may be controlled to dispense the first, second, third and fourth perpendicular adhesive beads  70 ,  72 ,  74 ,  76  in a manner similar to that described above for the adhesive dispensing apparatus  10 ,  10   a  of  FIGS. 1 and 3 .  
         [0032]     Referring now to  FIGS. 5-12 , there is shown another exemplary adhesive dispensing apparatus  10   c  according to the present invention. In these figures, the adhesive dispensing apparatus  10   c  includes first and second adhesive dispensing guns  36   c ,  38   c  mounted for linear movement along a horizontal support  140  which is oriented such that the first and second adhesive dispensing guns  36   c ,  38   c  travel in a direction oblique to the direction  16  of the conveyor path  16 . The pair of guns  36   c ,  38   c  are mounted in spaced relationship on a horizontal arm  141  which is in turn mounted for linear movement along the length of the horizontal support  140 . In an exemplary embodiment, the angle a between the direction of the first and second adhesive dispensing guns  36   c ,  38   c  and the conveyor direction  16  is 45 degrees. Advantageously, the movement of the first and second adhesive dispensing guns  36   c ,  38   c  along the horizontal support  140  may be controlled to closely match the speed of the container  12  along the conveyor  14  whereby the first and second adhesive dispensing guns  36   c ,  38   c  may apply the first, second, third and fourth perpendicular adhesive beads  70 ,  72 ,  74 ,  76  to the container flaps  20 ,  22 ,  24 ,  26  while the container  12  travels along the conveyor  14 . With reference to  FIGS. 2 and 5 - 8 , the operation of this embodiment of the adhesive dispensing system  10   c  will be explained.  
         [0033]     In  FIG. 5 , the container  12  is advanced along the conveyor  14  toward the first and second adhesive dispensing guns  36   c ,  38   c . In  FIG. 6 , the container  12  is positioned beneath the first and second adhesive dispensing guns  36   c ,  38   c  and the first and second guns  36   c ,  38   c  are turned on to dispense adhesive to the first major flap  20  while a motor  138  is simultaneously actuated to move the first and second adhesive dispensing guns  36   c ,  38   c  along the horizontal support  140 . Advantageously, the speed of the first and second guns  36   c ,  38   c  moving along the horizontal support  140  can be matched with the speed of the container  12  moving along the conveyor  14  such that the first, second, third and fourth adhesive beads  70 ,  72 ,  74 ,  76  may be dispensed to the flaps  20 ,  22 ,  24 ,  26  of the container  12  along a direction substantially perpendicular to the direction  16  of the conveyor  14 . In particular, and with further reference to  FIG. 2 , the first and second adhesive dispensing guns  36   c ,  38   c  are turned on to dispense the first and third adhesive beads  70 ,  74  beginning at the free edge  93  of the first major flap  20  and extending along the side edges  80 ,  86  of the first major flap  20  and onto a portion of the first and second minor flaps  24 ,  26 . The first and second guns  36   c ,  38   c  are then turned off while they continue to move along the horizontal support  140 , matching the speed of the container  12  along the conveyor  14 .  
         [0034]     Referring to  FIGS. 2 and 7 , as the first and second adhesive dispensing guns  36   c ,  38   c  approach the second major flap  22 , the first and second guns  36   c ,  38   c  are turned on to dispense adhesive to folded edge portions  84 ,  90  of the first and second minor flaps  24 ,  26  and along the first and second side edges  82 ,  88  of the second major flap  20  to create the second and fourth perpendicular adhesive beads  72 ,  76 . When the first and second guns  36   c ,  38   c  approach the free edge  92  of the second major flap  22 , the guns  36   c ,  38   c  are turned off and the first and second guns  36   c ,  38   c  are returned to the starting position, depicted in  FIG. 5 , in preparation for dispensing the perpendicular adhesive beads  70 ,  72 ,  74 ,  76  to a subsequent container  12   a  moving along the conveyor  14 . As shown in  FIG. 8 , as the leading edge  98  of the container  12  passes beneath the third adhesive dispensing gun  108 , the third gun  108  is turned on to dispense the parallel adhesive bead  78  along the free edge  92  of the second major flap  22  and between the second and fourth perpendicular adhesive beads  72 ,  76 . The third gun  108  is then turned off.  
         [0035]     The operation of the adhesive dispensing system  10   c  as described above for  FIGS. 5-8  may be used to create a siftproof pattern of adhesive on the container  12  when the containers  12 ,  12   a  are spaced along the conveyor  14  a distance S which is greater than the dimensions of the container  12 . When the spacing S between the containers  12 ,  12   a  is less than the dimensions of the container  12 , a modified method of dispensing adhesive to the containers  12 ,  12   a  using the apparatus  10   c  will have to be utilized as will be explained with reference to  FIGS. 2 and 9 - 12 .  
         [0036]     Referring to  FIGS. 2 and 9 , the first and second adhesive dispensing guns  36   c ,  38   c  are moved along the horizontal support  140  to dispense the perpendicular adhesive beads  70 ,  72 ,  74 ,  76  to the trailing and leading edges  106 ,  98  of successive containers  12 ,  12   a ,  12   b  moving along the conveyor  14 . As the trailing edge  106  of one container  12  and the leading edge  98  of another container  12   a  pass beneath the first and second adhesive dispensing guns  36   c ,  38   c , the motor  138  is actuated to move the first and second guns  36   c ,  38   c  linearly along the horizontal support  140  to track the speed of the containers  12 ,  12   a  along the conveyor  14  while the first and second adhesive dispensing guns  36   c ,  38   c  are turned on to apply first and third adhesive beads  70 ,  74  to the side edges  80 ,  86  of the first major flaps  20  (see  FIG. 2 ) and folded side portions  84 ,  90  of the first and second minor flaps  24 ,  26  (see  FIG. 2 ) of containers  12   a  and  12 , respectively, as depicted in  FIG. 10 . The first and second guns  36   c ,  38   c  are then turned off as the containers  12 ,  1   2   a  advance along the conveyor  14  and the first and second guns  36   c ,  38   c  continue to move along the horizontal support  140 .  
         [0037]     When the first and second guns  36   c ,  38   c  approach the folded edges  95  of the second major flaps  22  of the containers  12 ,  12   a , the first and second adhesive dispensing guns  36   c ,  38   c  are turned on to dispense second and fourth perpendicular adhesive beads  72 ,  76  to side edge portions  84 ,  90  of the first and second minor flaps  24 ,  26  and the side edges  82 ,  88  of the second major flaps  22  of containers  12   a  and  12 , respectively, as depicted in  FIG. 11 . As the first and second guns  36   c ,  38   c  approach the free edges  92  of the second major flaps  22 , the guns  36   c ,  38   c  are turned off to complete the second and fourth perpendicular adhesive beads  72 ,  76  on containers  12   a  and  12 , respectively.  
         [0038]     As the leading edge  98  of container  12  passes beneath the third adhesive dispensing gun  108 , the third gun  108  is turned on to dispense the parallel bead  78  along the free edge  92  of the second major flap  22 . As the trailing edge  106  passes beneath the third adhesive dispensing gun  108 , the third gun  108  is turned off to complete the parallel bead  78 . After the second and fourth adhesive dispensing beads  72 ,  76  have been applied to the containers  12 ,  12   a , the first and second guns  36   c ,  38   c  are returned to the starting position depicted in  FIG. 9  in preparation for dispensing adhesive to successive container  12   b  moving along conveyor  14  as described above. Because adhesive dispensing system  10   c  is configured to dispense adhesive to respective trailing and leading edges  106 ,  98  of successive containers  12 ,  12   a  at the same time, it will be recognized that the very first container  12  of a run will not have a perpendicular bead  72  applied proximate the first side edge  82  of the second major flap  22 . Accordingly, this bead  72  may be applied manually or by pre-manipulation of guns  36   c  and  38   c  prior to commencing automatic operation of the system.  
         [0039]     Referring to  FIG. 1   3 , there is shown yet another exemplary adhesive dispensing system  10   d  for applying the siftproof pattern of the present invention. In this embodiment, the first and second adhesive dispensing guns  36   d ,  38   d  are mounted on a first horizontal support  142  and are actuated by motors  144 ,  146  to move linearly along the horizontal support  142 . In addition, the horizontal support  142  is mounted for linear movement along second and third horizontal members  148 ,  150  which extend in a direction along the length of the conveyor  14 . A third motor  152  is coupled to the first horizontal support member  142  to move the first horizontal support member  142  in a direction parallel to the direction  16  of the conveyor  14  along horizontal members  148 ,  150 .  
         [0040]     In use, the first and second adhesive dispensing guns  36   d ,  38   d  are actuated to move transverse to the conveyor direction  16  and the first horizontal support member  142  is actuated to move parallel to the conveyor direction  16  while the first and second adhesive dispensing guns  36   d ,  38   d  are turned on to dispense the perpendicular adhesive beads  70 ,  72 ,  74 ,  76  to flaps  20 ,  22 ,  24 ,  26  of container  12 . Advantageously, the third motor  152  may control the speed of the first horizontal support member  142  to closely match the speed of the container  12  along the conveyor  14  whereby the perpendicular adhesive beads  70 ,  72 ,  74 ,  76  may be applied to the flaps  20 ,  22 ,  24 ,  26  of the container  12  in a much more controlled fashion. Specifically, as the leading edge  98  of the container  12  passes beneath the first and second adhesive dispensing guns  36   d ,  38   d , the guns  36   d ,  38   d  are turned on and the first and second motors  144 ,  146  are actuated to move the first and second guns  36   d ,  38   d  along the first horizontal support  142  to dispense the first and second perpendicular adhesive beads  70 ,  72  to the side edges  80 ,  82  of the first and second major flaps  20 ,  22  and portions  84  of the first minor flap  24  while the third motor  152  is actuated to move the first horizontal support  142  in a direction along the conveyor path  16  and at a speed substantially similar to the container  12 . After the first and second perpendicular beads  70 ,  72  have been applied to the container  12 , the first and second adhesive guns  36   d ,  38   d  are turned off and the third motor  152  returns the horizontal support  142  to its starting position.  
         [0041]     As the trailing edge  106  of the container  12  passes beneath the first and second adhesive dispensing guns  36   d ,  38   d , the first and second guns  36   d ,  38   d  are turned on and the first and second motors  144 ,  146  are actuated to move the guns  36   d ,  38   d  in a direction transverse to the conveyor direction  16  such that the third and fourth perpendicular beads  74 ,  76  are applied to the container  12  while the third motor  152  is actuated to move the horizontal support  142  in a direction along the conveyor direction  16  and at a speed which is substantially similar to the speed of the container  12 . After the third and fourth perpendicular beads  74 ,  76  have been applied to the container  12 , the first and second adhesive dispensing guns  36   d ,  38   d  are turned off and the third motor  152  returns the horizontal support  142  to its starting position. As the leading edge of the container  106  passes beneath the third adhesive dispensing gun  108 , the third gun  108  is turned on to dispense the parallel adhesive bead  78  along the free edge  92  of the second major flap  22  and between the second and fourth perpendicular adhesive beads  72 ,  76 . After the parallel bead  78  has been applied to the second major flap  22 , the third adhesive dispensing gun  108  is turned off.  
         [0042]      FIG. 14  depicts another exemplary adhesive dispensing system  10   e,  similar to system  10   c  of  FIGS. 5-12 , but having additional adhesive guns mounted to horizontal support  140  to accommodate increased line speeds. In the exemplary embodiment shown, first and second adhesive guns  36   e ,  38   e  and, in addition, third and fourth adhesive dispensing guns  160 ,  162  are mounted to horizontal support  140  by a carriage  164  which is moveable along support  140  so that the adhesive dispensing guns  36   e ,  38   e ,  160 ,  162  travel in a direction which is oblique to the conveyor path  16 . The adhesive dispensing guns  36   e ,  38   e ,  160 ,  162  may be coupled to first and second manifolds  166 ,  168 , respectively.  
         [0043]     Operation of the adhesive dispensing system  10   e  is similar to the system  10   c  previously described, wherein the guns  36   e ,  38   e ,  160 ,  162  dispense adhesive to the first and second major flaps  20 ,  22  and portions of the first and second minor flaps  24 ,  26  as container  12  travels along conveyor  14 . In particular, as successive cartons  12 ,  12   a  are moved along conveyor  14  and pass beneath the horizontal support  140 , a motor  138  is actuated to move the guns  36   e ,  38   e ,  160 ,  162  along the horizontal support  140  to track the speed of the containers  12 ,  12   a  along the conveyor  14  and the first, second, third and fourth adhesive dispensing guns  36   e ,  38   e ,  160 ,  162  are turned on to dispense adhesive beads to the containers  12 ,  12   a . The first and second guns  36   e ,  38   e  apply the third and fourth adhesive beads  74 ,  76  to the first and second major flaps  20 ,  22  and portions of the second minor flap  26  of the first carton  12  while the third and fourth adhesive dispensing guns  160 ,  162  apply the first and second adhesive beads  70 ,  72  to the first and second major flaps  20 ,  22  and portions of the first minor flap  24  of the second carton  12   a . After the first, second, third and fourth adhesive beads have been applied to the containers  12 ,  12   a , the adhesive guns  36   e ,  38   e ,  160 ,  162  are turned off and the carriage  164  is moved back along horizontal support  140  toward the starting position so that the process may be repeated with successive containers moving along conveyor  14 .  
         [0044]     As the leading edge  98  of successive containers  12 ,  12   a  pass beneath the fifth, stationary adhesive dispensing gun  170 , the fifth gun  170  is turned on to dispense the parallel bead  78  along free edge  92  of the second major flap  22 . As the trailing edge  106  passes beneath the fifth gun, the fifth gun  170  is turned off to stop the flow of adhesive and complete the parallel bead  78 .  
         [0045]     Referring to  FIG. 1   5 , there is shown yet another exemplary adhesive dispensing system  10   f,  similar to the adhesive dispensing system  10   d  shown in  FIG. 13 , but having four adhesive dispensing guns mounted to a horizontal support  142 . In this embodiment, first, second, third and fourth adhesive dispensing guns  36   f ,  38   f ,  180 ,  182  are mounted to a first horizontal support member  142  by a carriage  184  which is movable along the first horizontal support  142  to thereby move the first, second, third and fourth adhesive dispensing guns  36   f ,  38   f ,  180 ,  182  transversely with respect to conveyer direction  16 . As previously described above, with respect to  FIG. 13 , first horizontal support  142  is movable along second and third horizontal support members  148 ,  150  in a direction generally parallel to the conveyer direction  16 . The adhesive dispensing system  1 Of further includes a fifth, static adhesive dispensing gun  190  mounted to support  110  downstream of the first, second, third and fourth guns  36   f ,  38   f ,  180 ,  182 .  
         [0046]     Operation of the adhesive dispensing system  10   f  will now be described with reference to  FIGS. 2 and 15 . In use, motor  152  is actuated to move the first horizontal support member  142  in a direction generally parallel to the conveyer direction  16 , while closely matching the speed of a container  12  moving along the conveyer  14 , and another motor  178  is actuated to move carriage  184  along the first horizontal support member  142  in a direction transverse to the conveyer direction  16  while first, second, third and fourth adhesive dispensing guns  36   f ,  38   f ,  180 ,  182  are turned on to dispense parallel adhesive beads  70 ,  72 ,  74 ,  76  to the major and minor flaps  20 ,  22 ,  24 ,  26  of container  12  in a manner similar to that previously described. Specifically, first and second adhesive dispensing guns  36   f ,  38   f  may be used to apply perpendicular adhesive beads  72 ,  70 , respectively, to the first and second major flaps  20 ,  22  and portions of the first minor flap  24  near the leading edge  98  of container  12  while the third and fourth adhesive dispensing guns  180 ,  182  apply perpendicular adhesive beads  76 ,  74 , respectively, to the major flaps  20 ,  22  and portions of the second minor flap  26  near the trailing edge  106  of container  12  as the container  12  moves along the conveyer  14 .  
         [0047]     Alternatively, first and second adhesive dispensing guns  36   f ,  38   f  may be used to apply perpendicular adhesive beads  74 ,  76  proximate the trailing edge  106  of a first container  12  while the third and fourth adhesive dispensing guns  180 ,  182  apply perpendicular beads  70 ,  72  to the leading edge  98  of a subsequent container  12   a , in a manner similar to that previously described with respect to  FIGS. 9-12 . Operation of the adhesive dispensing system  10   f  in this manner is advantageous when containers  12 ,  12   a  are spaced along the conveyer  14  a distance which is less than the dimensions of the container  12 .  
         [0048]     After perpendicular adhesive beads  70 ,  72 ,  74 ,  76  have been applied to container  12 , the first, second, third and fourth adhesive dispensing guns  36   f ,  38   f ,  180 ,  182  are turned off and the first horizontal support  142  is moved along the second and third horizontal supports  148 ,  150  to reposition the adhesive dispensing guns  36   f ,  38   f ,  180 ,  182  with respect to the next container  12  moving along conveyer  14 . In an exemplary embodiment, carriage  184  may be controlled to move alternately from left to right, and then from right to left, with respect to  FIG. 15 , to dispense the perpendicular adhesive beads  70 ,  72 ,  74 ,  76  while accommodating high line speeds of cartons  12  moving along conveyer  14 .  
         [0049]     As the leading edge  98  of each container  12  passes beneath the fifth, stationary gun  190 , the fifth gun  190  is turned on to dispense the parallel bead of adhesive  78  along a free edge  92  of the second major flap  22 . As the trailing edge  106  of container  12  passes beneath the fifth gun  190 , the fifth gun  190  is turned off to stop the flow of adhesive and to complete the parallel bead  78  in a manner previously described.  
         [0050]     While the present invention has been illustrated by a description of various preferred embodiments and while these embodiments have been described in some detail, it is not the intention of the Applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. For example, it will be recognized that the motors  144 ,  146 ,  152  of the exemplary adhesive dispensing system  10   d  may be controlled to automatically adjust the spacing of adhesive dispensing guns  36   d ,  38   d  and the location of dispensed beads  70 ,  72 ,  74 ,  76  to accommodate various container sizes and arrangements. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus, methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of the Applicant&#39;s general inventive concept.