Abstract:
An apparatus for transporting and marking a substrate, such as a collapsed corrugated cardboard carton. A feeder station is configured to receive a substantially vertically aligned stack of substrates. An advancement assembly of the feeder station successively moves the lower portions of the substrates in an inboard direction and a tensioner assembly applies a clamping force to the upper portions of the substrates. A transfer assembly engages the innermost substrate in the stack to rotate and remove the substrate from the rest of the stack and provide the substrate to a transport and marking station, which drives the substrate past a marking mechanism. The transport and marking station advances the substrate into a gravity discharge station which induces sufficient tilt in the substrate so that, upon exiting of the substrate from the transport, gravity induces the substrate to rotate and fall in a controlled fashion into a completed stack.

Description:
RELATED APPLICATIONS 
   This application claims the benefit of U.S. Provisional Application No. 60/349,454 filed Jan. 18, 2002. 

   FIELD OF THE INVENTION 
   This invention relates generally to the field of material handling systems and more particularly, but not by way of limitation, to a system that transports and marks a stack of substrates such as collapsed corrugated cardboard cartons. 
   BACKGROUND 
   It is often desirable to mark a number of stackable, planar substrates in an automated fashion. For example, commercial entities often employ collapsible corrugated cardboard cartons to package and ship products. In such case it can be desirable to mark an external surface of the cartons with logos, shipping labels, barcodes, or other information prior to assembly and loading of the cartons. 
   While prior art substrate transport and marking methodologies have been found operable, there is a continued need for approaches that provide improved performance and throughput while reducing the need for user interaction. It is to such improvements that the present invention is directed. 
   SUMMARY OF THE INVENTION 
   In accordance with preferred embodiments, an apparatus is provided to transport and mark substrates such as collapsible, corrugated cardboard cartons. 
   The apparatus preferably includes a feeder station, a transport and marking station and a gravity discharge station. The feeder station is configured to receive a substantially vertically aligned stack of substrates from an attending user. 
   An advancement assembly of the feeder station successively moves the lower portions of the substrates in an inboard direction while a tensioner assembly applies a clamping force to the upper portions of the substrates. The stacked substrates are preferably oriented so as to lean forward at a slight angle in the inboard direction. 
   A transfer assembly engages the innermost substrate in the stack to rotate and remove the substrate from the rest of the stack. The transfer assembly then provides the substrate to a transport and marking station, which drives the substrate past a marking mechanism to apply the desired marking upon the substrate. Preferably, the marking mechanism comprises an inkjet printer. 
   The transport and marking station then advances the substrate into a gravity discharge station. The discharge station gradually induces a sufficient tilt in the substrate so that, upon exiting of the substrate from the transport, gravity induces the substrate to rotate and fall in a controlled fashion into a completed stack. 
   These and various other features and advantages which characterize the claimed invention will be apparent from a reading of the following detailed description and a review of the associated drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  provides an isometric view of a substrate transport and marking assembly constructed and operated in accordance with preferred embodiments of the present invention, the assembly comprising a feeder station, a transport and marking station and a gravity discharge station. 
       FIG. 2  provides a top plan view of the assembly of  FIG. 1 . 
       FIG. 3  provides a side elevational view of the assembly of  FIG. 1 . 
       FIGS. 4 and 5  provide selected views of a tensioner assembly of the feeder station of  FIGS. 1–3 . 
       FIG. 6  illustrates a transfer assembly of the feeder station. 
       FIGS. 7–9  generally illustrate operation of the transfer assembly to successively feed substrates from an input stack. 
       FIG. 10  illustrates a roller assembly of a drive system of the transport and marking station. 
       FIG. 11  provides a schematic representation of the roller assembly in conjunction with a drive belt of the drive system. 
       FIG. 12  provides a schematic representation of guide rails used by the transport and marking system to support an upper portion of the substrate. 
       FIG. 13  illustrates a portion of a channel used to slidingly support a bottom edge of the substrate through the transport and marking station. 
       FIG. 14  illustrates a portion of a channel used to slidingly support the bottom edge of the substrate through the gravity discharge station. 
       FIG. 15  generally illustrates a guide rail of the gravity discharge station, the guide rail and channel of  FIG. 14  cooperating to induce a tilt in the substrate. 
       FIGS. 16 and 17  provide side elevational views of the gravity discharge station to generally illustrate the manner in which substrates are stacked in a controlled fashion using gravity. 
   

   DETAILED DESCRIPTION 
     FIG. 1  provides an isometric view of a substrate transport and marking assembly  100  constructed and operated in accordance with preferred embodiments of the present invention. The assembly  100  preferably comprises a feeder station  102 , a transport and marking station  104  and a gravity discharge station  106 . The assembly  100  is preferably configured to handle a number of stacked, collapsible corrugated cardboard cartons, although other types of planar substrates can readily be processed as desired. 
   Generally, the feeder station  102  (feeder) is configured to receive and hold a stack of the cartons and feed the cartons one at a time to the transport and marking station  104  (transport). The transport  104  performs a marking operation on the cartons to encode the desired information. Such marking can include a printing operation such as with an inkjet printhead, the application of a label or layer of adhesive, etc. The cartons are then automatically stacked by the discharge station  106  (stacker).  FIG. 2  provides a side elevational view of the assembly  100  and  FIG. 3  provides a top plan view of the assembly  100 . 
   The various stations  102 ,  104  and  106  each include respective frames  108 ,  110  and  112  formed from a suitably rigid material, such as extruded aluminum beam members. Various portions of the frames  108 ,  110  and  112  are adjustable to accommodate a wide variety of different sizes, shapes and thicknesses of substrates. Thus, while the system  100  is configured to handle generally rectangularly shaped substrates, other, nonstandard shapes can be accommodated as well. 
   The stations are mounted on rollable, lockable castors  114  for ease of placement of the system. The stations are modular in that, for example, the feeder  102  and transport  104  can be used without the stacker  106 , in which case the substrates are automatically fed but manually stacked by a user. Likewise, the transport  104  and stacker  106  can be used without the feeder  102 , in which case the substrates are manually fed by a user but are automatically stacked. The stations are computer controlled using controller unit  116  and preferably, an associated personal computer (PC) with associated programming to provide a suitable graphical user interface. 
   The feeder  102  includes a pair of roller assemblies  118 ,  120  configured to support a stack of planar substrates. The roller assemblies  118 ,  120  are independently actuated by respective motor assemblies  122 ,  124  to advance and maintain a desired alignment of the substrates during operation. 
   As further shown in  FIGS. 4 and 5 , the feeder includes a retention assembly  126  used to retain the stack. The retention assembly  126  includes a stationary retention bar  128  and a moveable retention bar  130  which slidingly moves along transverse support  132 . An elastic retainer cord  134  (preferably made of “bungee-cord” type material) is routed along the support  132  as shown and attaches to the moveable retention bar  130 . 
   The stack is placed by the user in a substantially upright, vertical orientation upon the roller assemblies  118 ,  120  and preferably leaned forward (inboard) at a slight angle (such as about 5 degrees from vertical) so that a top portion of the innermost substrate in the stack bears against the stationary retention bar  128 . The moveable retention bar  130  is preferably hinged to allow retraction of a retention member  136  as the bar  130  is moved outboard beyond the stack. Once the retention member  136  clears the stack, it drops back to the normal orientation shown in  FIGS. 1–3  and the cord  134  causes the retention member  136  to bear against the outermost substrate in the stack to apply a compressive force to the stack. 
   Because the substrates are preferably angled forward, a first stack of substrates is loaded and the moveable retention bar  130  is moved behind the stack to retain the stack. During feeding of the first stack, a second stack can be placed on the roller assemblies  118 ,  120  outboard of the first stack. The combined weight of the respective stacks will be sufficient to cause the stacks to remain in the desired orientation without the need to immediately pull the moveable retention bar  130  outside beyond the second stack. Rather, the user can continue to add stacks as desired and, at any time as the first stack nears completion, the retention bar  130  can be retracted and placed outboard of the then loaded substrates. This greatly simplifies the tasks of the user attending the loading of the substrates. 
     FIG. 6  illustrates a transfer assembly  140  of the feeder  102  used to load each substrate in turn into the transport  104 . The transfer assembly  140  is configured for 3-axis movement in each of x (vertical), y (horizontal, inboard to outboard) and z (horizontal, longitudinal along the length of the system) axes. Respective x and y axis movements are controlled by actuators  142  and  144 ; z axis movement is carried out by movement of the transfer assembly  140  along transverse actuator  146  (best seen in top plan view of  FIG. 3 ). 
   The transfer assembly  140  preferably includes three (3) support arms  148  each supporting a compliant vacuum attachment cup  150 . Retractable piston dampers  152  allow respective movement of the cups  150  relative to the arms  148  while at the same time urging each cup back to a nominally centered position with respect to the arms. 
   Preferred operation of the transfer assembly is generally illustrated by  FIGS. 7–9 . In  FIG. 7 , the transfer assembly  140  is aligned to engage the innermost substrate (numerically denoted at  154 ) in the stack (denoted at  156 ). The transfer assembly  140  moves forward in the outboard (x-axis) direction until the cups  150  mate and establish a suction connection with the substrate  154 , after which the transfer assembly  140  retracts in the inboard (x-axis) direction to the position shown in  FIG. 8 . During this operation the top portion of the substrate  154  preferably remains clamped between the retention bars  128 ,  130  and the bottom portion of the substrate  154  is rotated outwardly (in the inboard direction). 
   The transfer assembly  140  next moves downwardly in the y-direction, thereby separating the substrate  154  away from the stack  156 . As the substrate  154  releases from the bar  128 , the dampers  152  operate to nominally orient the substrate  152  in a substantially vertical (y-axis) orientation as shown in  FIG. 9 . The transfer assembly  140  then advances the substrate  154  transversely in the z-axis to feed a leading edge into the transport  104 . 
   Optical sensors (not separately designated) detect the placement of the leading edge of the substrate  154  into the transport  104 , allowing the transport assembly  140  to release the substrate  154  once appropriate control over the substrate  154  has been established by the transport  104 . The transport assembly  140  then moves back to the position shown in  FIG. 7  to repeat the process with the next substrate in the stack. Preferably, a deck surface (not shown) is provided in the feeder station  102  to support a bottom edge of the substrate  154  as it is fed into the transport  104 . 
   The transport  104  utilities a belt/roller drive system  160  to advance the substrate  154  along the length of the transport, preferably at a constant linear velocity. The system  160  utilizes a continuous drive belt  162  which faces one or more adjacent roller assemblies  164 , as shown in  FIG. 10 . The roller assembly  164  includes a number of adjacent rollers  166  supported in a frame  168  which in turn is biased in a direction toward the substrate by spring assemblies  170 , as represented in  FIG. 11 . 
   A pair of guiding rails  172 ,  174  (shown in  FIGS. 1 and 12 ) allow the substrate to pass along the length of the transport  104  and serve to support the upper portion of the substrate so that the substrate remains in a nominally vertical orientation. An inkjet printer head  176  encodes the inboard surface of the substrate with the desired information as the substrate  154  moves thereacross. 
   The bottom edge of the substrate  154  is supported along the length of the transport  104  by a channel  178 , as shown in  FIG. 13 . The channel  178  preferably comprises a deck surface  180  and retaining sidewalls  182 ,  184 , all of which being formed of a durable, low friction material. Preferably, the channel  178  has a width of about 1-½ inches to accommodate a wide variety of different types of substrates, although other dimensions can be selected as desired depending upon the media utilized. 
   The drive system  160  preferably extends along the lower portion of the substrate, and the guiding rails  172 ,  174  align along the top portion of the substrate, allowing the inkjet printer  176  to be positioned as desired to mark substantially any portion or portions of the substrate. As mentioned previously, it will be readily apparent that multiple printers and/or other marking assemblies such as labeling, adhesive, painting, imprinting mechanisms etc. can be mounted to the transport  104  to mark the substrates. Moreover, while the system  100  as shown performs marking on only one side (the inboard surface) of the substrates, it will be readily apparent that the system  100  can be modified to provide outboard or dual side marking as desired. 
   The drive system  160  drives each substrate  154  in turn into the stacker  106 , and continues to do so until a trailing edge of the substrate exits the drive system  160 . No separate mechanized driving or actuation system is preferably included in the stacker, as such is unnecessary as will now be explained. 
   The stacker  106  preferably includes a channel  186  with deck surface  188  and sidewalls  190 ,  192  that nominally align with and are similarly oriented as the deck surface  180  and sidewalls  182 ,  184  of the transport. The channel  186  further includes a diverting sidewall  194  which extends inboard as shown in  FIG. 13  to a second sidewall  196 . This effects a narrowing of the channel  186  which displaces the bottom edge of the substrate  154  toward the inboard direction (y-axis) as the substrate is driven into the stacker  106  (by transport  104 ). 
   At the same time, guide rail  198  is skewed outboard at a slight angle, as shown in  FIG. 15 . An upper portion of the inner surface of the substrate  154  contactingly slides along the guide rail  198  Thus, the lower portion of the substrate is displaced outwardly (outboard), inducing a tilt in the substrate  154  as the substrate is successively advanced into the stacker  106 , as illustrated by  FIGS. 16 and 17 . The elevation and skew of the guide rail  198  are preferably adjusted such that, just after the transport  104  completes the driving of the substrate  154  into the stacker  106 , the substrate initiates a slow, gentle tumble (induced by gravity) into a completed stack  200 . 
   The various embodiments of the system  100  as described herein provide various advantages over the prior art. The feeder station allows repeatable, reliable and high speed feeding of the substrates into the transport while requiring little user intervention to maintain the feedstock in the feeder. This allows high-throughput operations, limited essentially only by the linear velocity of the transport  104 . Another advantage is the simplicity of the stacker; by inducing a tilt in the exiting substrates, the substrates can be easily and effortlessly stacked without the need for complex actuators or other mechanisms. This further cuts down on user interventions and simplifies processing. 
   It is to be understood that even though numerous characteristics and advantages of various embodiments of the present invention have been set forth in the foregoing description, together with details of the structure and function of various embodiments of the invention, this detailed description is illustrative only, and changes may be made in detail, especially in matters of structure and arrangements of parts within the principles of the present invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 
   In addition, although the embodiments described herein are generally directed to providing a system for processing collapsed cardboard cartons, it will be appreciated by those skilled in the art that the embodiments disclosed herein can be used to process other types of substrates, such as the printing of foamboard, posterboard or other types of media without departing from the spirit and scope of the claimed invention.