Abstract:
A block of bags for a product filling process includes a plurality of bags stacked in overlying relationship. Each bag of the block has a top edge, a bag mouth and opposite first and second side edges. First and second edge lines of perforations extend from edge points on respective opposite lateral edges of the bag. The edge points are spaced closely to the bag mouth of the bag. A central line of perforations extends between inner ends of the first and second edge lines of perforations. The central line of perforations is offset from the edge points, away from the bag mouth. A tear-off region is defined between the central line of perforations and the top edge. During automatic filling of the bad, the edge lines of perforations are torn to form an open bag mouth, and the central line of perforations is torn after filling to separate the bag from the block. The bag can alternatively also include first and second substantially longitudinal lines of perforations extending from the central line of perforations upwardly to the top edge of the bag, extending substantially from opposite ends of the central line of perforations, forming corner tear-off regions. The comer tear off regions can be removed before the filling operation. The invention also provides a bag filling platform which holds bag lip portions at a depressed elevation so that lip portions that remain on the platform after bags are separated do not interfere with the filling of subsequent bags.

Description:
TECHNICAL FIELD OF INVENTION  
         [0001]    The invention relates to thermoplastic bags which are stacked and blocked or unitized to be configured as a bag block. Furthermore, the invention relates to a method of successively filling the bags and separating the filled bags from the bag block.  
         BACKGROUND OF THE INVENTION  
         [0002]    The prior art related to the subject matter of the present invention includes U.S. Pat. Nos. 4,451,249; 4,342,564; and 4,699,607; PCT publication WO 99/48677; and European Patent EP 1 036 741, all herein incorporated by reference. Pending U.S. Ser. No. 09/517,968, filed Mar. 3, 2000, is also herein incorporated by reference.  
           [0003]    Bag blocks are used in food packaging assembly lines for bagging successively delivered products such as bread loaves. In the manufacture of bag blocks, one approach is described in U.S. Pat. No. 4,699,607 which involves producing two bags from each web segment or sheet wherein each segment is provided with a line of perforations defining a generally circular enclosed area located equidistant from the opposed edges of the sheet. A stack of such sheets is carried by a support, supporting a central medial band of the sheets. The sheets are unitized or blocked by a heated member projecting through the sheets in the perforated circular area of the sheets. To produce individual bag blocks, the sheet stack is cut along a line through the central medial band of the sheets.  
           [0004]    For a wicketed bag stack, holes can be prepunched into the sheet within or outside of the circular perforated area, before the sheets are stacked, and posts are provided on the support for receiving the succession of sheets impaled thereon via the prepunched holes. The subsequently blocked stack of wicketed bags is moved to a filling station wherein bags can be dispensed from the bag block by tearing individual bags from the bag block.  
           [0005]    Another method of forming a bag block follows the following steps:  
           [0006]    unwinding a layer of flat web of film from the unwind stand;  
           [0007]    folding the web of film over a folding board;  
           [0008]    applying a gusset in the web of film;  
           [0009]    entering the web of film into the bag forming machine via the infeed section;  
           [0010]    passing the intermittant moving part of the bag forming machine whereby a number of operations are done to the web, including the application of a perforation pattern;  
           [0011]    forming the bags by means of a sideweld or mixed weld sealing head;  
           [0012]    picking up and stacking bags on an index conveyor or an automated wicket handling system; and  
           [0013]    unitizing the stack of bags.  
           [0014]    The unwind step can be accomplished by a standard Hudson-Sharp Machine Co. model SDU 1600 unwind stand. It is an electrical surface-driven and braked unwind with a compensator for perfect web tension control. A web guiding system ensures a centered web exiting the unwind stand.  
           [0015]    The pre-centered web is pulled over the folding board by the infeed section of the bag machine, thereby forming a J-folded web whereby the lip is typically 35 to 45 mm wide. The folding board is a standard Hudson-Sharp Machine Co. 1500 mm folding board accessory. Optionally a bottom gusset is formed in the J-shaped web. The gusset former is a standard Hudson-Sharp Machine Co. 750 mm gusset former accessory.  
           [0016]    The infeed section is the first section of the Hudson-Sharp Machine Co. model 4750W basic wicket machine. It pulls the J-folded web into the bag machine from the gusset former, folding board and unwind by means of a set of nip rolls typically driven by an AC motor. This AC motor is controlled by a frequency controller which obtains a speed reference from the main machine controller and the infeed dancer which is part of the infeed section and located just stream downwards of the nip rolls.  
           [0017]    As a standard feature on the Hudson-Sharp Machine Co. model 4750W basic wicket machine, the intermittent moving part of the machine consists of two sets of servo driven nip rolls. In between the two pairs of nip rolls several attachments will modify the web of film such as by punching wicket holes for stacking and/or will detect the photo-eye mark for print registration. The formation of the bag is done in the sealing section of a standard Hudson-Sharp Machine Co. model 4750W. Typically the seals are side seals but mixed weld seals are also possible.  
           [0018]    The picking up and stacking of the bags is done in the pick-up and conveyor section of a standard Hudson-Sharp Machine Co. model 4750W. Wicketed bags have wicket holes. Wicket holes have heretofore been circular, triangular, star shaped, or diamond shaped. The bags are stacked on wicket pins going through the wicket holes during stacking. Although this stacking method produces the most ordered stacking quality, it isn&#39;t a necessity. The bags can be made without any kind of stacking holes and be stacked on needles. The unitizing of the stack can be done with a standard Hudson-Sharp Machine Co. pin blocker. Accordingly, heated pins can be driven through the stack of bags. The unitizing is done in the lip area above a region of perforations. The subsequently blocked stack of wicketed bags is moved to a filling station wherein bags can be dispensed from the bag block by tearing individual bags from the bag block. During the filling operation perforations are broken to create an opening of each bag large enough to receive the product being packaged.  
           [0019]    A method of filling and separating successive bags is described by the following steps:  
           [0020]    putting a stack in a stack recipient box and indexing the box to the bag filling area;  
           [0021]    opening the bag with an air nozzle or suction device;  
           [0022]    inserting the bag opening device or “spoons;” inserting the product into the bag;  
           [0023]    pulling the bag off the stack together with the product; and  
           [0024]    closing the bag and putting the bag on an offload conveyor.  
           [0025]    The Ibonhart model IB 360 filler feeds each stack of bags into the filling area by means of a “recipient box.” In a preparation station, an operator puts a stack of bags into a recipient box. When the recipient box in the filling area is empty, it is transferred away from the filling area and a prefilled new recipient box is placed into the filling position. In this process the stacks are presented substantially horizontally in the recipient box. A slight downward angle in the gusset area (i.e., bottom area of the bags when oriented upright) can be applied to lower the gusset area.  
           [0026]    Once the filling starts or restarts, bags are removed from the recipient box in the filling station. An air blast, aimed towards the opening of the top bag initially opens the top bag. Once the bag is opened, a set of spoons is inserted into the bag. The spoons engage the mouth of the bag and open it to a somewhat rectangular shape which corresponds to the shape of the product to be packaged. At this moment the bag is held by the spoons but is still connected to the rest of the stack by means of the wicket wire via the wicket holes. By means of a pusher the product is pushed into the bag. When the product hits the bottom of the bag, the still moving pusher will rip off the bag from the stack over the wicket wire. According to another known method, the spoons open the bag and then draw the bag in a reverse direction to the direction the spoons entered the bag, i.e., in a forward direction, to separate the bag from the block and at the same time to capture a stationary product within the moving bag. According to either method, the product together with the bag is then brought into another area of the filler where the bag is closed and transported for further handling.  
           [0027]    As the stack is depleted, the recipient box is moved vertically upward to maintain an equal filling plane. The filled bag is pulled off the stack, over the wicket wires. Since the bag is completely removed after each fill, the top of the remaining stack has full clearance without leaving any scrap which could interfere with the filling process. However, the entire lip is removed with the bag which can constitute an undesirable extra flap connected to each bag.  
           [0028]    Another method of filling a succession of bags is described in Australian published application AU 20002280 A1. According to this reference, a stack of bags is positioned on a support. The stack is held on holding rods and a flap region of the stack is clamped to the support. In this disclosure, the act of opening the bag breaks angularly oriented lines of perforations and substantially severs the top bag from corner portions of the bag flap entirely or except for short unperforated parts adjacent to the top edge of the bag. A product, such as a loaf of bread, is inserted into the open mouth of the bag and the bag with product inside is separated from the corner portions of the bag flap by breaking the short unperforated parts if they are present. A considerable amount of flap material is included with the separated bag. As the height of the bag decreases, the stacking table is moved up against the clamping plate.  
           [0029]    The present inventor has recognized the desirability of providing bags to be dispensed from a block of bags, wherein the bags are unitized in a bag block, each bag having a lip, wherein individual bags can be removed from the block with a minimized portion of the lip connected to the separated bag. The present inventor has also recognized the desirability of providing a method of filling such bags, wherein the bags are filled and successively torn from the block, wherein the lip portions remaining on the block do not interfere with the filling of subsequent bags.  
         SUMMARY OF THE INVENTION  
         [0030]    The present invention contemplates an improved design for wicketed and wicket-less blocked bag stacks or bag blocks wherein the bags are unitized within a lip or flap area thereof, and wherein a top bag body of the block is removed from the stack with a minimally-sized lip portion of web material adjoined thereto.  
           [0031]    In a first aspect of the invention, two edge lines of perforations extend inwardly from edge points on respective side edges of the bag, for a short distance. A central line of perforations extends between the two edge lines of perforations, offset from the edge points toward a top edge of the bag. Preferably, the central line of perforations is less easily torn than the two edge lines of perforations. The edge lines of perforations can be perpendicular to the side edges and parallel to the central line of perforations, or can be oblique to the side edges and to the central line of perforations. The central and two edge lines of perforations can be joined together by oblique or perpendicular line segments or curve segments of perforations, preferably being perforations which are easily torn, similar in degree to the tear strength of the first and second edge lines of perforations.  
           [0032]    A plurality of such bags are collected in a stack. A hot plate or pin is driven through comer lip areas defined by the adjacent side and top edges of each bag, and the two lines of perforations, and a hot plate or pin is driven through a central lip area defined between the top edge and the central line of perforations, to unitize or block the stack of bags.  
           [0033]    This embodiment can be incorporated into a wicket-less or wicketed bag. In the case of a wicketed bag, two wicket holes can be provided between the top edge and the central line of perforations.  
           [0034]    During a filling operation, the top bag is opened from a flat to a rectangular or pillow configuration with a substantially rectangular open mouth, adjacent to the lip. During the opening, the two edge lines of perforations, which are easily torn, separate or tear to accommodate the rectangular shape of the mouth. After the bag is filled, it is forcibly torn along the central line of perforations to separate the bag body from the bag block. The bag once separated, includes only a short lip portion, taken in a longitudinal direction of the bag. The bag block retains the remaining lip portion from the separated bag. As more bags are removed, the remaining lip portions of the previously separated bags can become an obstacle to filling subsequent bags, unless inventive apparatus are utilized.  
           [0035]    In this regard, according to a second aspect of the invention, the bag block is held on a support platform during filling, wherein the support platform includes an obliquely oriented lip support with an associated clamp which holds the remaining lip portions to the lip support. The remaining lip portions are held below the elevation of the bottom bag, such that remaining lip portions will not interfere with filling the entire stack of bags, beneath the original top bag.  
           [0036]    In another aspect of the invention, two substantially rectangular comer tear-off regions are provided at the upper comers of a bag. The corner tear-off regions are each substantially defined by one lateral edge of the bag, the top edge of the bag, one edge line of perforations as described in the first embodiment, and one of two short lines of perforations extending substantially from the one edge line of perforations to the top edge of the bag.  
           [0037]    Wicket holes can be provided within a central region of the lip. A hot plate or pin is passed through the stack of bags, within each of the corner tear-off regions, and through the central region of the lip, to unitize the stack of bags as a bag block.  
           [0038]    The comer tear-off regions are removed before the block reaches a filling station. Preferably, plural stacked comer regions are removed together from a formed bag stack or bag block by clamping the comer regions and clamping the remaining bag stack or block separately and differentially moving the two clamping mechanisms to separate the comer regions from the stack or block. Alternately, the comer regions are removed from each bag during bag formation on the bag forming machine. The corner tear-off regions are clamped, and the remaining bag is separately clamped. Using differential movement between the clamps, the corner regions are removed from the bag by tearing along the perforations. It is also possible that the bag block with comer regions attached thereto is shipped to the filling station, such as a bakery, where the corner regions are removed prior to or during filling. The comer tear-off regions are removed before the filling operation to facilitate the initial opening of the bag mouth from a flat condition to a rectangular shape.  
           [0039]    Numerous other advantages and features of the present invention will be become readily apparent from the following detailed description of the invention and the embodiments thereof, from the claims and from the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0040]    [0040]FIG. 1 is a perspective view of a first embodiment stack of bags in accordance with the present invention;  
         [0041]    [0041]FIG. 2 is a plan view of the first embodiment stack of bags of FIG. 1, shown in a prior stage of manufacture;  
         [0042]    [0042]FIG. 3A is a plan view of the second embodiment stack of bags in accordance with the present invention, in a first stage of manufacture;  
         [0043]    [0043]FIG. 3B is a plan view of the second embodiment stack of bags in a second stage of manufacture;  
         [0044]    [0044]FIG. 3C is a plan view of the second embodiment stack of bags in a third stage of manufacture;  
         [0045]    [0045]FIG. 4A is a perspective view of a bag filling apparatus of the invention in a first stage of operation;  
         [0046]    [0046]FIG. 4B is a perspective view of the bag filling, apparatus of FIG. 4A in a second stage of operation;  
         [0047]    [0047]FIG. 4C is perspective view of the bag filling apparatus of FIG. 4A in a third stage of operation;  
         [0048]    [0048]FIG. 5 is a sectional view taken generally along line  5 - 5  of FIG. 4A;  
         [0049]    [0049]FIG. 6 is a perspective view of a further alternate embodiment bag block of the present invention;  
         [0050]    [0050]FIG. 7A is a diagrammatic perspective view of a bag being opened as shown in FIG. 4C; and  
         [0051]    [0051]FIG. 7B is a diagrammatic perspective view of a bag being opened, comparable with FIG. 7A, except using a bag from the block shown in FIG. 6. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0052]    While this invention is susceptible of embodiment in many different forms, there are shown in the drawings, and will be described herein in detail, specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated.  
         [0053]    Exemplary apparatus for manufacturing, stacking and blocking bag stacks are described in the aforementioned U.S. Pat. No. 4,699,607 and U.S. Ser. No. 09/517,968, filed Mar. 3, 2000, both herein incorporated by reference.  
         [0054]    [0054]FIG. 1 illustrates a block  20  of bags  24  according to a first embodiment of the invention. Each bag  24  includes a tubular body  26  having a front wall  28  and a back wall  32  which extends upwardly of the front wall, forming a back wall top flap or lip  36 . The bag body has first and second sealed or fold-formed side edges  40 ,  42 , a top edge  46 , and a bag mouth  47 .  
         [0055]    Extending perpendicularly and inwardly from a first edge point  40   a  on the first side edge  40 , is a first edge line of perforations  52 . Extending perpendicularly and inwardly from a second edge point  42   a  on the second side edge  42 , is a second edge line of perforations  54 . The first and second edge points  40   a ,  42   a  can be located on or very close to the bag mouth  47 . A first angular segment of perforations  56  extends from an end of the first edge line of perforations  52 , obliquely toward the top edge  46 . A second angular segment of perforations  58  extends from an end of the second edge line of perforations  54 , obliquely toward the top edge  46 . A central line of perforations  59  extends between ends of the segments of perforations  56 ,  58 . The central line of perforations  59  can be located at a distance d 1  from the mouth  47  that is greater than a distance d 2  between either the first and second edge points  40   a ,  42   a  and the mouth  47 . Advantageously, this distance d 1  is about 10 to 15 mm.  
         [0056]    A lip tear-off region, or distal lip portion, or remaining lip portion  60  is defined by the lines of perforations  52 ,  54 ,  56 ,  58 ,  59 , the side edges  40 ,  42 , and the top edge  46  of the bag body  26 . A bag lip portion  61  is defined by the lines of perforations  52 ,  54 ,  56 ,  58 ,  59 , the side edges  40 ,  42 , and the bag mouth  47 . A unitizing area  66  is formed through the stack  20  within the lip tear-off region  60 , between the top edge  46  and the line  52 , substantially perpendicularly to the plane of the back wall  32 . A second unitizing area  68  is formed within the lip tear-off region  60  between the edge  46  and the line  59 , and through the stack  20 , substantially perpendicularly to the plane of the back wall  32 . A third unitizing area  69  is formed within the lip tear-off region  60  between the edge  46  and the line  54 . The first, second and third unitizing areas  66 ,  68 ,  69  are formed by penetrating the stack  20  with one or more hot plates or pins, which form holes through the stack and melt-fuses together the bags  24  within the areas  66 ,  68 ,  69 . It is possible that the holes formed within the areas  66 ,  68 ,  69  can be made large enough to subsequently receive rods for guiding or supporting the stack.  
         [0057]    Wicketing holes  70 ,  72  and/or pin holes  74 ,  76  can be located within the lip region  60  which are utilized as described in U.S. Pat. No. 4,699,607 or U.S. Ser. 09/517,968. The wicketing holes  70 ,  72  and/or the pin holes  74 ,  76  act in conjunction with posts and/or sharpened pins to align bags during stack formation. Subsequently, the wicketing holes  70 ,  72 , or the holes formed within the areas  66 ,  68 ,  69 , can receive wires, posts or rods to guide and/or support the stack and allow individual bags to be torn from the stack.  
         [0058]    It is advantageous that the line of perforations  59  is perpendicular to the tear-off or pull direction F, or an alternate pull direction F′, when a user or automated equipment is separating a bag  24  from the stack  20 . In this way, maximum tensile stress is exerted on residual web material along the perforated line  59 .  
         [0059]    Although the edge lines of perforations  52 ,  54  are shown to be perpendicular to the side edges  40 ,  42 , and parallel to the central line of perforations  59 , it is also encompassed by the invention that the edge lines of perforations  52 ,  54  are oblique to the side edges  40 ,  42 , extending at an acute angle to the side edges from the points  40   a ,  42   a  toward the central line of perforations  59 .  
         [0060]    [0060]FIG. 2 illustrates the first embodiment of the invention in a prior stage of assembly. In this stage, the step of forming the unitizing areas  66 ,  68 ,  69  is optionally preceded by pre-drilling or otherwise forming holes  66   a ,  68   a ,  69   a . This assists the hot plates or pins rods in penetrating and unitizing the stack through the holes  66   a ,  68   a ,  69   a.    
         [0061]    FIGS.  3 A- 3 C show an alternate embodiment bag block  100  in three stages of manufacture. Those features of the alternate bag block  100  which are identical to features in the previously described bag block  20  are identified with like reference numerals. The alternate bag block  100  includes substantially longitudinal lines of perforations  102 ,  104  which substantially extend from ends of the central line of perforations  59  to the top edge  46  of the bag block. The substantially longitudinal lines of perforations  102 ,  104 , the angular segments of perforations  56 ,  58  and the edge lines of perforations  52 ,  54  form corner tear-off regions  108 ,  110  respectively.  
         [0062]    Although the substantially longitudinal lines of perforations  102 ,  104  are shown to be perpendicular to the central line of perforations  59 , it is also encompassed by the invention that the substantially longitudinal lines of perforations can be obliquely angled to the longitudinal direction such as being angled toward each other toward the top edge of the bag.  
         [0063]    [0063]FIG. 3B illustrates the bag block  100  of FIG. 3A, but further including central unitizing regions  68   b ,  68   c  located within a central lip region  114  that is located between the tear-off comer regions  108 ,  110 .  
         [0064]    [0064]FIG. 3C illustrates the bag block  100  of FIG. 3B with the comer regions  108 ,  110  removed. The central lip region  114  is unitized throughout the stack by the regions  68   b ,  68   c . The central lip region  114  can be held by wickets through the wicket holes  70 ,  72  or by other means as described below during dispensing of the bags at a filling station. As each bag is filled it is then removed by separation along the central line of perforations  59 . Because the comer regions are removed, each successive top bag can be opened into a rectangular configuration easily.  
         [0065]    [0065]FIG. 4A illustrates the block  100  in, a filling station  120  supported on a support table  124 . The support table  124  includes a substantially horizontal support plate  128  and an oblique, lip supporting plate  132 . The central lip region  114  is supported on the plate  132  and clamped thereon by a clamp member  138 . Alternatively, or additionally, wicket pins  139  supported by a bracket  140  (shown in FIG. 5) can penetrate through a back side of the plate  132  through the wicket holes  70 ,  72  to hold the lip region  114  on the plate  132 .  
         [0066]    [0066]FIG. 4B illustrates an air delivery device  142  blowing an air stream onto the top bag  24  particularly into the mouth  47  of the top bag  24 . The air stream tends to open the bag from a flat condition to a rectangular or pillow shaped configuration. Alternately, or additionally, a suction device or suction cup  143  can be used to open the mouth  47 . The suction device  143  can be configured to engage the bag wall at the mouth and then to move upwardly to open the mouth. An opening device  150  which includes an upper opening mechanism or spoons  154  and a lower opening mechanism or spoons  158  is configured to be inserted into the open mouth  47  of the top bag  24 .  
         [0067]    [0067]FIG. 4C shows the opening device  150  inserted into the bag mouth  47  and then having the spoons  154 ,  158  pivoted to expand the device  150  to hold the bag  24  in the open configuration. A product  162  is inserted into the bag  24  through the opening device  150 . The product  162  is inserted via a pusher  166  which pushes the product  162  through the bag and against an end wall  170  thereof with a force sufficient to tear the top bag  24  along the perforation line  59  to separate the top bag  24  from the block  100 . This force is along the direction F.  
         [0068]    [0068]FIG. 5 illustrates the filling station  120  in section. This figure illustrates that the oblique plate  132  allows the perforation line  59  to be located generally at or below a top surface  128   a  of the support table  128 . This allows the succession of bag opening mouths  47  to be located at a higher elevation than the remaining lip regions  114  such that the remaining lip regions  114  do not interfere with the filling of subsequent mouth of the bags down to a bottom bag  202 . Although it is advantageous to have the bottom bag  202  located above the remaining lip region  114 , it may also be acceptable for overall non-interference to have the remaining lip regions  114  held at an elevation only below some or most, but not all, of the bags in the block. For example, it may be because of the size of the product with respect to the size or shape of the bag mouth that it is only necessary that the remaining lip regions  114  on the plate  132  be below a bag mouth that is only half way down the original block of bags.  
         [0069]    According to another known filling method, the spoons open the bag and then draw the bag in a reverse direction to the direction the spoons entered the bag, i.e., in a forward direction, along the line F′, to separate the bag from the block and at the same time to capture a stationary product within the moving bag. The apparatus of FIGS.  4 A- 4 C are equally applicable to this method, with the exception of the pusher.  
         [0070]    [0070]FIG. 6 illustrates an alternate bag block  300 . This bag block  300  includes alternate bags  324  having alternate tubular bag bodies  326 . Each body  326  includes a front wall  328  and a back wall  332  which extends upwardly of the front wall, forming a back wall top flap or lip  336 . The bag body has first and second sealed or fold-formed side edges  340 ,  342 , a top edge  346 , and a bag mouth  347 . Similar to the bag block  100  described in FIGS.  3 A- 3 C, corner portions  408 ,  410  are removed from the bag block  300 , before the bag block is delivered to a filling station. For purpose of description of the perforations, the corner portions are shown with the bag block, slightly separated therefrom.  
         [0071]    Extending obliquely and inwardly from a first edge point  340   a  on the first side edge  340 , is a first edge line of perforations  352  (shown already broken from the corner portion  408 ). Extending obliquely and inwardly from a second edge point  342   a  on the second side edge  342 , is a second edge line of perforations  354  (shown already broken from the corner portion  410 ). The first and second edge points  340   a ,  342   a  are located on or below the original bag mouth  347 , i.e., the bag mouth  347  before the corner regions are removed. Before the comers  408 ,  410  are removed, the edge lines of perforations  352 ,  354  are formed through the front wall  328  and the back wall  332  of the body  326  at the edge points  340   a ,  342   a . A first substantially longitudinal segment of perforations  356  (shown already broken from the corner portion  408 ) extends from an end of the first edge line of perforations  352 , toward the top edge  346 . A second substantially longitudinal segment of perforations  358  (shown already broken from the comer portion  410 ) extends from an end of the second edge line of perforations  354 , toward the top edge  346 .  
         [0072]    The corner regions  408 ,  410  are removed by breaking the lines of perforations  352 ,  354 ,  356 ,  358 . The finished bag mouth  347 , once the corner regions  408 ,  410  are removed, thus includes a laterally arranged central region  347   a  and two oblique edge regions  347   b ,  347   c.    
         [0073]    A central line of perforations  359  extends between ends of the first and second lines of perforations  352 ,  354 . A lip tear-off region, or distal lip portion, or remaining lip portion  360  is defined by the lines of perforations  352 ,  354 ,  356 ,  358 ,  359 , and the top edge  346  of the bag body  326 . A bag lip portion  361  is defined by the lines of perforations  352 ,  354 ,  359 , and the central region  347   a  of the bag mouth  347 .  
         [0074]    Unitizing areas  368   a ,  368   b ,  368   c  are formed through the stack of bags  24  within the lip tear-off region  360 . The unitizing areas  368   a ,  368   b ,  368   c  are formed by penetrating the stack of bas  324  with one or more hot plates or pins, which form holes through the stack and melt-fuses together the bags  324  within the areas  68   a ,  368   b ,  368   c  as described previously. Wicketing holes  370 ,  372 , or other functional holes as previously described, can be located within the lip region  360 .  
         [0075]    During a filling operation, the central line of perforations  359  and the wicket holes  370 ,  372  perform the same function as that described in the prior embodiments.  
         [0076]    One advantage of the configuration of FIGS.  6  is demonstrated in FIGS. 7A and 7B. FIG. 7A illustrates, in diagrammatic fashion, the opening of a bag body  128  configured in accordance with FIGS.  3 A- 3 C. The spoons  154 ,  158  stretch open the bag in a vertical direction. This causes an offset loading due to the loads T 1  and T 2 . The load T 1  is offset from the load T 2  due to the extending lip  61 , extending by the distance d 2 . This offset loading, although small due to the small distance d 2 , can possibly cause an increased incidence of seal failure along side edge seals  40   c , at the point  40   d . Given greater distances d 2  than that of the present invention, it has heretofore been known to include a side seal discontinuity or “seal saver”  40   e  in the side seal  40   c  to stop the propagation of a rip down the side seal during bag opening.  
         [0077]    [0077]FIG. 7B illustrates that according to the embodiment of FIG. 6 , there is no offset loading of T 1  and T 2  at the side seal  40   c  and no enhanced stress at the point  40   d  to cause propagation of a rip down the side seal. The need for a seal discontinuity  40   e  is obviated.  
         [0078]    Although the alternate bag block  100  is shown in use with the filling station  120  in FIGS.  4 A- 5 , the bag block  20  shown in FIGS.  1 - 2  and  6  can also be mounted on the filling station  120  shown in FIGS.  4 A- 5  as well. In that application, when the air source  142  opens the bag, the side edge perforations  52 ,  54  would be broken to allow for the bag to assume a pillow shape or rectangular configuration as shown in FIG. 4B. Additional needs, such as the suction device or suction cup  143  (shown in FIG. 4B) applied on the top layer of the bag and then moving vertically upward, for example, might be necessary to break the edge perforations.  
         [0079]    In any of the embodiments of FIGS.  1 - 2 ,  3 A- 3 C, or  6 , rather than hot plates or pins penetrating through the tear-off region, the stack of bags can be unitized by a hot plate being applied to a top edge of the stack of bags. Either a flat blade or a cylindrical pin can be used to unitize a top region of the stack. Alternatively, the wicket hole itself can be the location of unitizing around its inner circumference. Furthermore, rather than a single flat hot plate unitizing a flat region of the stack of bags, a plurality of hot pins, arranged in parallel, can be applied to a top surface of the stack of bags in order to unitize the bag stack. Such arrangements for unitizing are described in detail in U.S. Ser. No. 09/517,968.  
         [0080]    Although melt-fusing is an effective method of unitizing the bag stack, it is also possible to unitize the stack by the use of adhesive, such as applied on the exposed, stacked top edges of the bags in the stack.  
         [0081]    Although the embodiments illustrate “lines” or “segments” of perforations as being straight or linear, such lines could also be curved lines or segments without departing from the invention.  
         [0082]    From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific articles or apparatus illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims.