Abstract:
A processing station ( 10 ) for high speed printing, handling and die cutting of blanks or blanks ( 26 ) is provided which includes a clamshell-type die cutter ( 12 ), as well as a feeding device ( 14 ) including a transfer mechanism ( 16 ) and pickup member ( 18 ). The station ( 10 ) may also include a printing assembly ( 20 ) and a cut blank removal assembly ( 22 ). In operation, individual blanks ( 26 ) from a stack ( 28 ) are successively fed by the transfer mechanism ( 16 ) and are picked up by the member ( 18 ); the blanks are delivered to the die cutter ( 12 ) when the latter is open and after die cutting the removal assembly ( 22 ) is employed to lift the cut blank ( 26 ) from the cutter ( 12 ) and shift the blank ( 26 ) to a slide plate ( 116 ). A pusher bar ( 122 ) then operates to move the cut blank ( 26 ) to an outfeed conveyer ( 146 ). The station ( 10 ) is capable of handling relatively thick corrugated blanks ( 26 ) at high speed and without constant operator attendance.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention is broadly concerned with the improved processing equipment designed to rapidly handle, imprint, die cut and transfer sheet-type blanks and especially relatively thick corrugated blanks. More particularly, the invention is concerned with such equipment, and corresponding methods, wherein blanks are successively fed along a generally horizontal path through a printing station and then through handling equipment; at this point a movable pickup member is employed for lifting and delivering the blanks to the open platens of a clamshell die cutter. After cutting, a removal assembly picks up the processed blanks and delivers them to an outfeed conveyer for downstream processing.  
           [0003]    2. Description of the Prior Art  
           [0004]    Clamshell die cutters have long been available and used in the paper converting industry. Generally speaking, clamshell die cutters include a relatively massive frame supporting a pair of platens. Normally, one platen is stationary whereas the other is moved through an arcuate path between a full open position allowing a blank to be placed on the platen, to a cutting position where the blank is die cut. One of the platens carries a cutting die so that, when the movable platen is closed, an accurate die cut is achieved.  
           [0005]    In typical operations with clamshell die cutter, an operator stands near the device and manually removes a cut blank from the opened platen and then places a fresh uncut blank thereon. This is of course an extremely labor-intensive undertaking, given that the operator must constantly attend the die cutter and insure that each individual blank is placed in perfect alignment for proper cutting. Moreover, any carelessness on the part of the operator quickly leads to a relatively serious industrial accident, where the operator inadvertently leaves his hand or arm between the platens as they close.  
           [0006]    It has been proposed in the past to provide automatic feeders for clamshell die cutters. One such design incorporates an elevator wherein a stack of blanks is successively elevated and delivered into the die cutter. However, such elevator units have only a limited blank capacity and thus must be reloaded on a frequent basis. For example, where corrugated blanks are processed, the elevator feeder can accommodate only about 150 blanks. This means that the feeder must be reloaded approximately every 7 minutes.  
           [0007]    High throughput die cutting devices have also been used in the past which differ fundamentally from clamshell cutters. These units operate by moving a die-carrying platen in a reciprocal, up-and-down fashion. With these die cutters, blanks are successively fed between the opened platens, and are die cut as the upper platen moves downwardly; the cut blanks are then removed from the platen assembly for further processing. While die cutters of this variety are capable of high speed operation even when corrugated blanks are processed, they are extremely expensive as compared with clamshell die cutters.  
           [0008]    There is accordingly a need in the art for improved blank processing equipment making use of a relatively inexpensive clamshell die cutter while nevertheless achieving the high operating speeds of reciprocal die cutters.  
         SUMMARY OF THE INVENTION  
         [0009]    The present invention overcomes the problems outlined above and provides processing equipment in the form of a station including a clamshell die cutter and a feeding device operable to feed individual feedstock blanks into the clamshell cutter when the latter is open, with the feeding device comprising a transfer mechanism for individually shifting respective blanks from a stack thereof toward the die cutter, and a pickup member that moves cut blanks from the feeding device to the die cutter when the latter is open. Preferably, the overall station includes a printing assembly designed to print each successive blank, together with a cut blank removal assembly designed to pick up a cut blank from the die cutter for transfer and downstream processing.  
           [0010]    Preferably, the transfer mechanism comprises a reciprocal pusher plate operable to engage and shift the bottom most blank from a stack thereof along with a transfer belt presenting a generally horizontal upper run orientated to receive the blank and deliver the same for pickup. The printing assembly is advantageously located between the pusher plate and the transfer belt. The preferred pickup is vacuum-operated and includes a shiftable arm operated in timed relationship with the pusher plate and transfer belt. The blank removal assembly likewise includes a vacuum pickup member, supported on arms so that it is moved from a pickup position adjacent the clamshell die when the latter is open, and a delivery position. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 is a side elevational view of a processing station in accordance with the invention, including a clamshell die cutter and a feeding device operable to feed individual sheet blanks into the die cutter, and to remove cut blanks therefrom, shown with the die cutter in its open position and with the feeding device depositing a blank onto the open platen of the die cutter;  
         [0012]    [0012]FIG. 2 is a plan view of the station depicted in FIG. 1;  
         [0013]    [0013]FIG. 3 is a vertical sectional view taken along line  3 - 3  of FIG. 2 and illustrating the construction of the processing station;  
         [0014]    [0014]FIG. 4 is a sectional view similar to that of FIG. 3, but illustrating the clamshell die cutter in its closed, die cutting configuration;  
         [0015]    [0015]FIG. 5 is a sectional view similar to that of FIG. 4, but showing the clamshell die during opening thereof and with the pickup member operatively engaging a cut blank for removal thereof;  
         [0016]    [0016]FIG. 6 is a sectional view similar to that of FIG. 5, illustrating the die cutter moving to its full open position, with the pickup member depositing a cut blank onto the slide plate of the sheet removal assembly, and with the pickup member moving a fresh, uncut blank toward the die cutter;  
         [0017]    [0017]FIG. 7 is a fragmentary, front view of the processing station, showing a cut blank deposited on the slide plate of the blank removal assembly; and  
         [0018]    [0018]FIG. 8 is a fragmentary, front view similar to that of FIG. 7, and showing the cut blank delivered to an outfeed conveyer. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0019]    Turning now to the drawings, a processing station  10  in accordance with the invention broadly includes a clamshell die cutter  12 , a feeding device  14  having a transfer mechanism  16  and a pickup member  18 . In addition, the preferred station  10  also includes a printing assembly  20 , a cut blank removal assembly  22  and a stripper table  24 (see FIG. 2). The station  10  is designed to individually print, transfer and die cut a series of blanks  26  provided in a stack  28 , and to thereafter remove the cut blanks for downstream processing. The station  10  is particularly suited for the high speed handling of relatively thick corrugated sheet blanks, although virtually any other type of feedstock may be handled as well.  
         [0020]    In more detail, the clamshell die cutter  12  includes a pair of relatively shiftable platens  30 ,  32  together with powered operating means  34  for repetitively moving the platens together to effect a die cut, followed by separation of the platens. Thus, FIG. 1 illustrates the full-open position of the cutter  12 , with the platen  30  separated from cooperating platen  32 , whereas FIG. 4 shows the platens in their adjacent, cutting position; the remaining Figures depict the platens in intermediate positions. The platen assembly is provided with an appropriate die (not shown) which provides the desired cutting of the individual blanks  26 .  
         [0021]    The transfer mechanism  16  is made up of a printing tower  36  and a specially designed blank handler  38 , with the tower  36  and handler  38  oriented in an in-line manner as illustrated in FIG. 2. In particular, the tower  36  includes an upright frame  40  supporting a horizontal feed table  42  the latter having a vacuum, hold-down section  44 , an upstanding stack retainer  46  and a powered, shiftable pusher plate  48  which is slidable along table  42  for successively delivering the bottom most blank  26  for processing. The printing assembly  20  is also supported on frame  40  and includes a conventional printing roll train  50  with a plate roller  52 , inking roller  54 , smoothing roller  56  and backing roller  58 . In addition, it will be observed that the printing assembly  20  also has a pair of adjacent entrance nip rollers  60 ,  62  upstream of the plate and backing rollers  52 ,  58 . The roll train  50  is powered by a conventional drive including motor  64  and a gear train (not shown) housed within upright housing  66 .  
         [0022]    The handler  38  has an upright frame  68  presenting inner and outer, spaced apart sidewalls  70 ,  72  (see FIGS.  7 - 8 ), with a lower table  74  between the inner walls. The table  74  is supported by struts  76  and crosspieces  78  welded or otherwise affixed to the inner sidewalls; the crosspieces  78  also support an upper slide plate  79 . The table  74  supports a pair of endmost shafts  80 ,  82  via bearing mounts  84 . The shafts  80 ,  82  are each equipped with four laterally spaced apart belt-supporting rollers  86 , and each aligned pair of these rollers has a transfer belt  88  trained therearound. It will be seen that the upper runs of the belts  88  pass over and are supported by upper slide plate  79 . A sheet hold-down roller  90  is positioned slightly above the belts  88  and is supported by a crossframe  92  extending between inner walls  70 .  
         [0023]    The handler is also equipped with a vacuum pickup member  18  which includes a pair of elongated spaced apart pickup arms  94  each having an inner connection end  96  and an outer pickup end  98 . A support link  100  is pivotally coupled to each arm  94  intermediate the ends thereof, with the lower ends of the links  100  pivotally connected to the frame  68  through legs  102 . The inner ends  96  of the arms  94  are connected to corresponding reciprocating belts  104  secured to each wall  70  and trained about pulleys  106 . As best seen in FIGS.  7 - 8 , the ends  96  are secured to the adjacent belts  104  through connection clips  108 . A pickup head  110  extends between and is pivotally mounted to the outer ends  98  of the arms  94 . The head  110  includes an elongated vacuum bar  112  having a series of spaced apart vacuum cups  114  along the length thereof. The bar  112  includes short pivotal links for connection to the arm ends  98  as shown. Also, a vacuum line (not shown) is provided in operative communication with bar  112  and cups  114 .  
         [0024]    The cut sheet removal assembly  22  is supported by frame  68  and includes a slide plate  116  including a central section  117  and laterally spaced marginal sections  118  separated by slots  120 . A central pusher bar  122  rides atop section  117  and is movable by means of two chain drive assemblies  124  located beneath and along the side edges of section  117 . For this purpose, the pusher bar has marginal connectors securing the bar to the respective assemblies  124 . As best seen in FIGS.  7 - 8 , the marginal sections  118  have upstanding alignment guides  126 ,  128 , and the forward section of the slide plate  116  includes an upstanding bail  130  with arcuate guides  132 .  
         [0025]    The overall assembly  22  also has a pair of elongated cut blank pickup arms  134  which are each pivotally coupled to the frame  68  between the sidewalls  70 , 72 . The arms  134  have a dogleg configuration and support a transversely extending vacuum head  136  with the latter having a plurality of spaced vacuum pickup fingers  138  mounted on pivotal crossbar  140 . As illustrated, vacuum tubing  142  is provided which communicates with head  136  and fingers  138  during operation of the station  10 . Timed movement of the pickup head  136  is effected through motor  144  operatively coupled with the arms  134 .  
         [0026]    An outfeed conveyer  146  is positioned adjacent the upper end of slide plate  116  and is oriented transverse to the in-line arrangement of tower  36 , handler  38  and die cutter  12 . The conveyer is itself entirely conventional including shiftable belt  148  powered through motor  150 . The output end of the conveyer  146  feeds product to the conventional product stripper  24 , whereupon waste and finished blanks are directed from the stripper.  
         [0027]    The various components of station  10  are operated in timed relationship in the manner described below. Preferably, the timing between sheet handler  38  and clamshell die cutter  12  is established through use of a common driveline (not shown). The remaining components, including those of tower  36 , are timed through use of conventional sensors and microprocessor control. Of course, such timing expedients are well known to those skilled in the art.  
         [0028]    Operation  
         [0029]    Initially, a stack  28  of feedstock blanks  26  is placed on feed table  42  adjacent retainer  46 . Also, the printing assembly  20  is readied for operation with an appropriate plate mounted on roller  52  and ink supplied to roller  54 .  
         [0030]    The pusher plate  48  is next operated in order to move the lowermost blank  26  from the stack  28  towards printing assembly  20 . As illustrated in FIG. 5, the pusher plate  48  is initially upstream of the retainer  46 , but upon movement thereof beneath the retainer  46  as illustrated in FIGS.  2 - 6 , the lowermost blank is moved forwardly across vacuum section  44  and into the nip presented by rollers  60 , 62 . These rollers advance the blank through the nip defined between plate roller  52  and backing roller  58 , where the underside of the blank is printed (see FIG. 5). As the printed blank passes from the assembly  20 , it encounters the upper runs of the belts  88  and is thus moved toward die cutter  12 . The hold down roller  90  ensures that the blank lies flat upon the belts  88 . As the blank reaches the end of the belts  88 , the pickup member  18  comes into play to engage, lift and deliver the blank into die cutter  12 . Specifically, the initial orientation of the pickup member  18  is illustrated in FIG. 5 where the vacuum cups  114  engage and grip the upper surface of the blank; thereupon, the arms  94  are moved by shifting of the belts  104  in a forward direction as illustrated in FIGS. 6 and 1- 3  until the blank is positioned over the fully opened platen  30 . At this point the vacuum to the cups  114  is relieved, thereby allowing the blank to fall under the influence of gravity onto platen  30 . Although not shown in detail, it will be understood that the platen  30  would typically include alignment blocks or similar structure to insure that the blank is properly seated on the platen face.  
         [0031]    Next, the arms  94  are withdrawn by a reverse movement of the belts  104  so that member  18  reassumes the FIG. 5 position, and simultaneously the platen  30  is pivoted to the cutting position depicted in FIG. 4, so as to cut the blank in the desired configuration. The platen  30  is then reopened and the cut sheet removal assembly  22  is operated. This involves movement of the support arms  134  in a forward direction from the retracted position of FIG. 1 to the fully extended pickup position of FIG. 5. As the fingers  138  approach the surface of the cut blank within die cutter  12 , a vacuum is drawn through tubing  142 . This enables the fingers to grip the cut blank in order to lift the blank upwardly and rearwardly to a position above slide plate  116  (see FIG. 6). The vacuum is then relieved, allowing the sheet to drop onto the slide plate  116 . Proper placement and alignment of the sheet on the slide plate is assured by virtue of the guides  126 ,  128  and  132 . At this point the pusher bar  122  (which is stationed as shown in FIG. 7 adjacent the forward end of the plate  116 ) is shifted by movement of the drive assemblies  124  upwardly along the length of the plate  116 . This serves to push the blank upwardly past the upper end of the plate  116  and onto belt  148  of conveyer  146 . The latter then moves the blank to the stripper  24  for final processing.  
         [0032]    It will of course be understood that in normal high speed operations the various components described above will be operating simultaneously, i.e., during retraction of the pickup member  18 , the removal assembly  22  and die cutter  12  are also operating. Of course, as explained above, the timing of the components of station  12  can be effected in a number of ways all well within the skill of the art.