Information
                
                    - 
                         Patent Grant Patent Grant
- 
                         6446810 6446810
 
         
    
    
        
            
                - 
                    Patent Number6,446,810
- 
                    Date FiledMonday, December 18, 200024 years ago 
- 
                    Date IssuedTuesday, September 10, 200223 years ago 
 
     
    
        
            
                - 
                            Inventors
- 
                            Original Assignees
- 
                                ExaminersAgents
                - Christie, Parker & Hale, LLP
 
 
     
    
        
            
                - 
                            CPC
- 
                            US ClassificationsField of Search
                - US
- 206 554
- 383 8
- 383 9
- 383 37
 
- 
                            International Classifications
- 
                            
                
 
     
        
     
    
        
        
    
        
            
        Abstract
A pack of self-opening bags with a front, rear, and co-joined side walls, with front and rear tabs extending from top edges of the front and rear walls. The tabs have a curved aperture slits therein, and the tabs are frangibly adhered together with contact adhesive. The slit has a main cut section, a first curved end section at one end, and a second curved end section at the opposite end. The first curved section has a curve that extends upwardly and inwardly from the main cut section. The second curved section has a substantially semi-circular curve that extends from the main cut section in a direction towards the bottom edge of the tab and has an end that is substantially perpendicular to and adjacent the main cut section. In one embodiment, the first curved section is dashed.             
         
        
            
                    Description
  
    
      
        FIELD OF THE INVENTION
      
    
    
      
        This invention relates to plastic bags, and more particularly to a pack of tabless T-shirt bags or merchandise bags, trash bags, and the like made preferably of polyolefins, and method of manufacturing same, which can be used with or without bagging racks and which provide for reliable self-opening of the bags as each bag is removed from the pack of bags.
      
    
    
      
        BACKGROUND OF THE INVENTION
      
    
    
      
        Since the mid-1980's, the use of plastic shopping bags has grown dramatically due to the great advantage plastic bags have over bags made of other materials, such as paper. Many types of plastic bags are made of low or high density polyethylene (LDPE and HDPE, respectively), but can be made of any of the polyolefins. LDPE and HDPE bags are stronger, lighter and much more compact to store than paper bags, saving valuable storage space at the merchants' checkout counter and storage areas. These attributes also make these bags less expensive to transport. LDPE and HDPE bags can be manufactured and sold at a fraction of the cost of competing paper bags, making them the bags of choice for merchants. LDPE and HDPE bags are also actually more environmentally friendly than paper bags since they require about 70 percent less energy to manufacture than competing paper bags and are readily recyclable, and when not recycled, are non-toxic when incinerated or disposed of in landfills.
      
    
    
      
        Many groceries stores and other merchants now use a style of plastic bag to bag groceries and other merchandise commonly referred to as T-shirt bags. T-shirt bags are pleated bags which are closed, by heat sealing, at a bottom edge, and have a pair of integral loop handles extending upwardly to define an open mouth of the bag therebetween. T-shirt bags usually have a central tab that extends from front and rear walls of the bag. Each of the front and rear walls have a central tab that extends from the walls, respectively. The central tabs have aligned apertures into which bagging racks are received.
      
    
    
      
        Because high density polyethylene (HDPE) has a greater resistance to stretching and deformation than LDPE plastic, HDPE plastic is generally used for making T-shirt bags, although LDPE and other polyolefins can also be used. T-shirt bags are normally provided in packs of aligned bags and these packs of bags are usually used in conjunction with bagging racks.
      
    
    
      
        T-shirt bags are generally manufactured using a continuous tube of HDPE plastic, or other plastic material having the desired color, thickness, and diameter, formed on a extrusion machine. The continuous plastic tube is passed over rollers to roll the continuous plastic tube onto a spool.
      
    
    
      
        The newly formed continuous plastic tube is usually subjected to corona surface treatment, if the bags to be formed from the continuous tube of HDPE are to be printed on one or both sides. It has been found that corona surface treatment, or other known methods to electrically and chemically change the entire outer surface of the continuous plastic tube, contributes somewhat to the self-opening feature of applicants' plastic bag pack system.
      
    
    
      
        After being corona surface treated and rolled (if the bags might be printed), the roll of continuous plastic tube is unrolled and pleated on a pleating machine. A bagging machine then heat seams and cuts sections of the pleated tube at top and bottom edges to form closed and flattened pleated bags of a desired length and width, with the pleated sides being at both sides of the flattened pleated bags. These sections are often referred to as pillowcases. The pillowcases are eventually stacked in aligned stacks.
      
    
    
      
        Thereafter, hydraulic die cutting or other cutting methods are utilized to remove material at the stacked pillowcases' upper portions to form the handles and tab portions. Each loop handle has four layers of plastic material since they are cut out from the pleated side portions of the bag.
      
    
    
      
        Despite the many advantages HDPE T-shirt bags have over paper bags, they are not self-standing like thicker and stiffer paper bags with a discreet flat bottom. This is due to their relatively thin and flexible material. In grocery stores settings, where quick and easy loading of bags is desirable, packs of T-shirt bags are generally supported on a bagging rack as merchandise is loaded into the bags to overcome the lack a of self-standing ability.
      
    
    
      
        The packs of T-shirt bags suffer from drawbacks. Prominent among these drawbacks include the lack of a convenient and easy to manufacture self-opening feature, to eliminate the need for the box person to struggle to open up each bag in the pack of bags.
      
    
    
      
        In order to prepare a T-shirt bag for loading with merchandise, it is desired that only the first layer of the bag material of the top bag are pulled away from the pack, thereby opening just the top bag. Since the HDPE material is very thin, typically between 0.5 and 1 mil thick (0.0005 and 0.001 inches), it is sometimes difficult for the checkout clerk or box person to grasp just the top layer of bag material. One can often see a sponge or source of tacky material, such as a glue stick, retained at the top of bagging racks, with which the checkout clerk or box person can dampen his or her fingers to aid in grasping just the top layer of material of the bag. However, this takes additional time and effort in the bagging process. This cycle has to be repeated with each successive bag to be loaded.
      
    
    
      
        In addition, the bag packs systems typically leave waste “books” of heat bonded central tabs on the bagging rack. These books accumulate on the bagging rack and are generally thrown out. In those styles of packs of bags which employ a central tab slit through their central tabs for mounting the pack of bags on a tab receiving hook of a bagging rack, it is sometimes difficult to engage the slitted central tab with the tab receiving hook.
      
    
    
      
        There are also so-called “tabless” designs, in which no portion of the bag is left on the bagging rack. In these bag designs, each bag will tear through a suspension aperture completely as each bag is removed.
      
    
    
      
        Existing tabless bag designs that are provided with a self-opening feature utilized frangible bonding to cause each bag to open. However, use of frangible bonding as a self-opening feature can be problematic because the strength of the bond formed depends on several factors, including the thickness of the plastic film, the degree of corona treatment, the size and shape of the die used to form the areas of frangible bonding, the pressure applied to the dies, and static changes in the bag materials. While adhesive have been used to create a self-opening feature in tabbed bag designs, use of adhesive in a flapless design is unknown to the inventor. Use of adhesive in the central tabs of packs of bags would be particularly useful to assure self-opening inasmuch as a pulling force close to the tearing slit will ensure that the bag will reliably open.
      
    
    
      
        SUMMARY OF THE INVENTION
      
    
    
      
        It is desirable to have a pack of plastic bags which can be easily manufactured, yet which provides for reliable self-opening of each bag of the pack of bags, does not leave a book of plastic tabs on the bagging rack, can be easily placed on a bagging rack, and does not tear the lower portion of the bag.
      
    
    
      
        A pack of self-opening plastic bags for use with a bagging rack has a mouth for receipt of merchandise. Each plastic bag in the pack of bags has a mouth tab portion between its two upwardly extending handles. The mouth tab portions extend from front and rear walls along sides of the mouth. Through the stack of bag, in the mouth tab portion is a curved aperture slit for receiving a bagging pack hook member of a bagging rack. The curved aperture slit has a main cut section that is substantially parallel with the bottom edges of the walls, and two curved end sections at respective ends of the main cut section. One end section curves towards a top edge of the tab portion, and another end section curves in an opposite direction and wraps back under the main section until it is substantially perpendicular to and adjacent the main cut section. In one embodiment, the first curved section is dashed.
      
    
    
      
        Contact adhesive bonding is preferably utilized near the curved aperture slit. The handles also have holes for use in suspending the pack of self-opening bags on the bagging rack. Due to the adhesive bonding between adjacent bags, as an outermost bag is removed from the pack of bags on the bagging rack, the next adjacent bag in the pack of bags automatically self-opens into an open position for loading with merchandise.
      
    
  
  
    
      
        BRIEF DESCRIPTION OF THE DRAWINGS
      
    
    
      
        
          FIG. 1
        
         is a perspective view of a pack of self-opening T-shirt bags of the invention;
      
    
    
      
        
          FIG. 2
        
         is a fragmentary perspective view of an upper area of one embodiment of the pack of bags of 
        
          FIG. 1
        
        , shown before the pack of bags is loaded on a bagging rack;
      
    
    
      
        
          FIG. 3
        
         is a partial perspective view of the one embodiment of the pack of bags of 
        
          FIG. 1
        
         hanging on the bagging rack, as a topmost bag is first opened up for loading with merchandise and released from the pack of bags;
      
    
    
      
        
          FIG. 4
        
         is a perspective view of the bagging rack loaded with bags of 
        
          FIG. 1
        
        , shown with the topmost bag of the pack of bags torn free from the tab hook of the bagging rack and opened up for loading with merchandise;
      
    
    
      
        
          FIG. 5
        
         is a further perspective view of the bag and pack of bags of 
        
          FIG. 4
        
         as the top bag is removed from the bagging rack and the next bag is automatically readied for loading;
      
    
    
      
        
          FIG. 6
        
         is a perspective view of a pack of self-opening merchandise bags of the invention;
      
    
    
      
        
          FIG. 7
        
         is a fragmentary perspective view of an upper area of one embodiment of the pack of merchandise bags of 
        
          FIG. 6
        
        ;
      
    
    
      
        
          FIG. 8
        
         is a perspective view of a blade used to form curved aperture slits for the embodiments of the packs of T-shirt bags of FIG. 
        
          
            1
          
        
         and the merchandise bags of 
        
          FIG. 6
        
        ;
      
    
    
      
        
          FIG. 9
        
         is a fragmentary perspective view of another embodiment of a pack of T-shirt bags, shown before the pack of bags is loaded on a bagging rack;
      
    
    
      
        
          FIG. 10
        
         is a fragmentary perspective view of an upper area of another embodiment of the pack of merchandise bags, shown before the pack of bags is loaded on a bagging rack; and
      
    
    
      
        
          FIG. 11
        
         is a perspective view of a blade used to form curved aperture slits for the embodiments of the packs of T-shirt and merchandise bags shown in 
        
          FIGS. 9 and 10
        
        .
      
    
    
      
        
          FIG. 12
        
         is a flowchart showing the method of the invention.
      
    
  
  
    
      
        DETAILED DESCRIPTION OF THE INVENTION
      
    
    
      
        Referring now more specifically to the drawings, reference numeral 
        
          
            10
          
        
         designates the self-opening bag pack formed in accordance with the invention of multiple individual bags 
        
          
            12
          
        
        . The manufacturing process employed to manufacture the pack of self-opening bags 
        
          
            10
          
        
         of the invention is similar to that used to manufacture conventional T-shirt bags. As shown in 
        
          FIGS. 1
        
         to 
        
          
            5
          
        
        , each individual bag 
        
          
            12
          
        
         has a lower body portion 
        
          
            14
          
        
        , a front wall 
        
          
            20
          
        
        , a rear wall 
        
          
            22
          
        
        , pleated side walls 
        
          
            24
          
        
         joining together the front and rear walls, and two loop handles 
        
          
            16
          
        
         extending from the lower body portion 
        
          
            14
          
        
        . The loop handles 
        
          
            16
          
        
         each extend from a top edge 
        
          
            32
          
        
         of the front wall 
        
          
            20
          
        
         and couple to the top edge 
        
          
            32
          
        
         of the rear wall 
        
          
            22
          
        
        .
      
    
    
      
        The T-shirt bags 
        
          
            12
          
        
         are sealed together at their bottom edges 
        
          
            26
          
        
         to form the lower body portion 
        
          
            14
          
        
         and at their upper edges 
        
          
            28
          
        
         to form the loop handles 
        
          
            16
          
        
        . Heat seaming is the preferred method of sealing the bottom and upper edges 
        
          
            26
          
        
         and 
        
          
            28
          
        
         of the bags 
        
          
            12
          
        
        , but other means can be employed, if desired.
      
    
    
      
        In between the two loop handles 
        
          
            16
          
        
         and the front and rear walls 
        
          
            20
          
        
        , 
        
          
            22
          
        
         is a mouth 
        
          
            18
          
        
         for receiving items into the bag 
        
          
            12
          
        
        . A mouth tab portion 
        
          
            30
          
        
         extends from top edges 
        
          
            32
          
        
         of both the front and rear walls 
        
          
            20
          
        
         and 
        
          
            22
          
        
         between the two loop handles 
        
          
            16
          
        
        . The tab portions 
        
          
            30
          
        
         each have a top edge 
        
          
            36
          
        
        , and a bottom edge 
        
          
            35
          
        
         that couples the tab portions 
        
          
            30
          
        
         to the respective top edges 
        
          
            32
          
        
        .
      
    
    
      
        Each mouth tab portion 
        
          
            30
          
        
         in the embodiment of 
        
          FIGS. 1
        
         to 
        
          
            5
          
        
         has a curved aperture slit 
        
          
            34
          
        
        . As will be discussed further below, these curved aperture slits 
        
          
            34
          
        
         are used to suspend the pack of bags 
        
          
            10
          
        
         on a bagging rack 
        
          
            50
          
        
        . A slit 
        
          
            38
          
        
         is made at the upper portion of the tab portion 
        
          
            30
          
        
         when the bag is opened up on the bagging rack 
        
          
            50
          
        
        . The slit 
        
          
            38
          
        
         extends from the top edge 
        
          
            36
          
        
         and communicates with the curved aperture slit 
        
          
            34
          
        
        , as described in more detail below.
      
    
    
      
        Each curved aperture slit 
        
          
            34
          
        
         has a main cut section 
        
          
            42
          
        
         that is preferably substantially parallel with the bottom edges 
        
          
            26
          
        
        , a first curved cut section 
        
          
            44
          
        
         coupled to one end of the main cut section, and a second curved cut section 
        
          
            46
          
        
         coupled to an opposite end of the main cut section. The first section 
        
          
            44
          
        
         preferably curves to extend from the main cut section in a direction upwardly and inwardly from the main cut section and towards the top edge 
        
          
            36
          
        
         and center of the tab 
        
          
            30
          
        
        . The slit 
        
          
            38
          
        
         extends from an end of the first curved section 
        
          
            44
          
        
         to the top edge 
        
          
            36
          
        
         of the tab 
        
          
            30
          
        
        .
      
    
    
      
        The second section 
        
          
            46
          
        
         is substantially curved and extends from the main cut section 
        
          
            42
          
        
         in a direction towards the bottom edge 
        
          
            35
          
        
         of the tab portion 
        
          
            30
          
        
        , and then back upwardly in a substantially vertical orientation.
      
    
    
      
        Near the curved aperture slit 
        
          
            34
          
        
         spots of contact adhesive 
        
          
            39
          
        
         are applied between the front and rear walls of adjacent bags in the bag pack and frangibly bond together adjacent layers of the plastic material of the bags 
        
          
            12
          
        
         in the pack of self-opening bags 
        
          
            10
          
        
        . The spots of contact adhesive 
        
          
            39
          
        
         provide a self-opening feature of the pack of bags 
        
          
            10
          
        
        , as discussed in more detail below.
      
    
    
      
        The pack of self-opening bags 
        
          
            10
          
        
         also have handle holes 
        
          
            40
          
        
         passing through the handles 
        
          
            16
          
        
         for use in suspending the pack of self-opening bags 
        
          
            10
          
        
         on the bagging rack 
        
          
            50
          
        
        . These handle holes 
        
          
            40
          
        
         have areas of frangible cold pressure bonding 
        
          
            41
          
        
         and/or spots of contact adhesive near the handle holes 
        
          
            40
          
        
        . The frangible bonds/contact adhesive retain the layers of plastic material of the handles 
        
          
            16
          
        
         of the pack of bags 
        
          
            10
          
        
         in stacked alignment.
      
    
    
      
        The pack of self-opening bags 
        
          
            10
          
        
         is designed to be used in conjunction with the bagging rack 
        
          
            50
          
        
        , such as that shown in 
        
          FIGS. 3
        
         to 
        
          
            5
          
        
        . The bagging rack 
        
          
            50
          
        
         has a support base 
        
          
            52
          
        
        , a support back 
        
          
            54
          
        
         with a top edge 
        
          
            60
          
        
         and two bag pack handle suspension arms 
        
          
            56
          
        
         extending from the top edge 
        
          
            60
          
        
         and over the support base 
        
          
            52
          
        
        . A bagging pack hook member 
        
          
            58
          
        
         extends from the support back 
        
          
            54
          
        
         over the support base 
        
          
            52
          
        
         and is acutely angled away from the support base and back. The bagging rack hook member 
        
          
            58
          
        
         is positioned approximately midway on the top edge 
        
          
            60
          
        
         between the two bag pack handle suspension arms 
        
          
            56
          
        
        .
      
    
    
      
        The pack of self-opening bags 
        
          
            10
          
        
         is retained on the bagging rack 
        
          
            50
          
        
         through receipt of the mouth tab portion 
        
          
            30
          
        
         onto the hook member 
        
          
            58
          
        
        . Referring to 
        
          FIGS. 3
        
         to 
        
          
            5
          
        
        , the pack or packs of self-opening bags 
        
          
            10
          
        
         of 
        
          FIG. 1
        
         are placed on the bagging rack 
        
          
            50
          
        
         by passing the handle holes 
        
          
            40
          
        
         in the handles 
        
          
            16
          
        
         over the bag pack handle suspension arms 
        
          
            56
          
        
         of the bagging rack 
        
          
            50
          
        
         and then engaging the curved aperture slits 
        
          
            34
          
        
         of the mouth tab portion 
        
          
            30
          
        
         with the bagging rack hook member 
        
          
            58
          
        
        .
      
    
    
      
        After loading the pack or packs of self-opening bags 
        
          
            10
          
        
         on the bagging rack 
        
          
            50
          
        
        , a checkout clerk or box person first grasps only the front wall 
        
          
            20
          
        
         of the outermost bag 
        
          
            12
          
        
         and pulls the bag toward himself. The front wall 
        
          
            20
          
        
         of the outermost bag 
        
          
            12
          
        
         is torn free from the pack of self-opening bags 
        
          
            10
          
        
         at its mouth tab portion 
        
          
            30
          
        
        . In particular, the slit 
        
          
            38
          
        
         formed by the hook member 
        
          
            58
          
        
         ripping through the mouth tab portion 
        
          
            30
          
        
        . The ripping through the tab portion 
        
          
            30
          
        
         happens prior to the separation of adhesively bonded together bags because it takes less force to rip the tab portion than to break the adhesive bonding 
        
          
            39
          
        
        . As a result, the rear wall 
        
          
            22
          
        
         of the outermost bag 
        
          
            12
          
        
         stays attached to the bagging hook member 
        
          
            58
          
        
        . While the adhesive 
        
          
            39
          
        
         is near the tearing slit 
        
          
            34
          
        
        , adhesive can be placed lower on the tab portion 
        
          
            30
          
        
         or below the tab and below the mouth on the upper portion 
        
          
            39
          
        
         of the bag pack.
      
    
    
      
        After the outermost bag 
        
          
            12
          
        
         is loaded with the merchandise through the mouth 
        
          
            18
          
        
        , its handles 
        
          
            16
          
        
         are disengaged from the bag pack handle suspension arms 
        
          
            56
          
        
         of the bagging rack by pulling the bag 
        
          
            12
          
        
         away from the support back 
        
          
            54
          
        
         of the bagging rack 
        
          
            50
          
        
        . By virtue of the bonding 
        
          
            39
          
        
        , 
        
          
            41
          
        
        , and slight adhesion between adjacent layers of plastic material, the front wall 
        
          
            20
          
        
         and the side walls 
        
          
            24
          
        
         of the next bag 
        
          
            12
          
        
         adjacent the outermost bag 
        
          
            12
          
        
         in the pack of self-opening bags 
        
          
            10
          
        
         are pulled with the loaded bag 
        
          
            12
          
        
         as shown in FIG. 
        
          
            5
          
        
        .
      
    
    
      
        The next bag 
        
          
            12
          
        
         automatically opens its mouth 
        
          
            18
          
        
         without any need for the checkout clerk or box person to grasp the material of the front wall 
        
          
            20
          
        
         of the adjacent bag 
        
          
            12
          
        
        . Slight further pulling of the outermost bag 
        
          
            12
          
        
         by the box person, along with the load of the merchandise facilitates separation of the outermost bag 
        
          
            12
          
        
         from its adjacent (next) bag 
        
          
            12
          
        
        . The adjacent bag 
        
          
            12
          
        
         remains with its mouth 
        
          
            18
          
        
         open in the bagging rack 
        
          
            50
          
        
         because it still is frangibly bonded along its rear wall to another adjacent bag on a side opposite the outermost bag 
        
          
            12
          
        
        . Thereafter, by merely withdrawing consecutive bags from the top of the pack of self-opening bags 
        
          
            10
          
        
        , the adjacent bags 
        
          
            12
          
        
         open up without the box person needing to manually and individually disconnect the front wall 
        
          
            20
          
        
         of the outermost bag 
        
          
            12
          
        
        .
      
    
    
      
        As best shown in 
        
          FIGS. 3
        
         to 
        
          
            5
          
        
        , when the outermost bag 
        
          
            12
          
        
         is pulled to disengage from the pack of self-opening bags 
        
          
            10
          
        
        , most of the pulling tension is delivered along the top edges 
        
          
            35
          
        
         of the bag's mouth 
        
          
            18
          
        
         to the top edge 
        
          
            36
          
        
         of the tab portion 
        
          
            30
          
        
        . This pulling tension along with the adhesive bonding 
        
          
            39
          
        
        , 
        
          
            41
          
        
         causes the rear wall 
        
          
            22
          
        
         of the outermost bag 
        
          
            12
          
        
         along with the front wall 
        
          
            20
          
        
         of the adjacent bag 
        
          
            12
          
        
         to tear free from the pack of self-opening bags 
        
          
            10
          
        
         at their mouth tab portions 
        
          
            30
          
        
        . Accordingly, each tab portion tears to form the tearing nick 
        
          
            38
          
        
        , typically leaving no portion of the bag 
        
          
            12
          
        
         on the bagging rack 
        
          
            50
          
        
        .
      
    
    
      
        For the tension placed on the tab portion, the direction of failure along the plastic bag tends to extend in a direction that is tangent to ends of the aperture slit. In particular, when the tab portion is tensioned, the tab portion tears from the end of the first curved section 
        
          
            44
          
        
         towards the top edge 
        
          
            36
          
        
         of the tab portion 
        
          
            30
          
        
         to form the slit 
        
          
            38
          
        
        . Similarly, when the area around the second curved section 
        
          
            46
          
        
         is tensioned, the tab portion 
        
          
            30
          
        
         tears from the end of the second curved section to the main section. Accordingly, when the tab portion is tensioned, the plastic bag is usually torn in a direction opposite the lower portion 
        
          
            14
          
        
        . This limits the possibility of tearing the lower portion 
        
          
            14
          
        
         of the bag.
      
    
    
      
        
          FIGS. 6 and 7
        
         show an embodiment of a self-opening bag pack 
        
          
            90
          
        
        , wherein the pack 
        
          
            90
          
        
         has merchandise bags 
        
          
            91
          
        
        . The bags 
        
          
            91
          
        
         are substantially the same shape and have substantially the same features as the bags 
        
          
            12
          
        
         of FIG. 
        
          
            1
          
        
        . The main difference is that the bags 
        
          
            91
          
        
         do not have handles similar to handles 
        
          
            16
          
        
         of FIG. 
        
          
            1
          
        
        . The merchandise bags 
        
          
            91
          
        
         each have a mouth tab portion 
        
          
            92
          
        
         with a curved aperture slit 
        
          
            94
          
        
         and an adhesive bonding 
        
          
            96
          
        
        . The spots of adhesive bonding 
        
          
            102
          
        
         are positioned along top outer edges 
        
          
            100
          
        
         of the bag 
        
          
            91
          
        
        . A bagging rack (not shown) for use with this embodiment is similar to that used with the previous embodiments, except there are no suspension arms for receipt of handles. Each bag 
        
          
            91
          
        
         has a lower portion 
        
          
            104
          
        
         that is similar to the lower portion 
        
          
            14
          
        
         described with regard to FIG. 
        
          
            1
          
        
        . Also, the mouth tab portion 
        
          
            92
          
        
         is similar to the mouth tab portion 
        
          
            30
          
        
        .
      
    
    
      
        
          FIG. 8
        
         illustrates a blade 
        
          
            64
          
        
         used to form the curved aperture slit 
        
          
            34
          
        
         of the embodiment shown in 
        
          FIGS. 1-2
        
         and the aperture slit 
        
          
            94
          
        
         of the embodiment shown in FIG. 
        
          
            7
          
        
        . Prior to being die cut, at least one spot of adhesive is applied to each bag as it is stacked into a pillowcase of bags. The spots of adhesive will preferably be applied in a location that will be in close proximity to aperture slit when formed. Standard contact adhesive spitters, available from a variety of manufactures can be used to apply the contact adhesive. Precise registration of the stack of pillowcase and precise placement and control of the amount of the adhesive is necessary, otherwise during the manufacturing process, the die blades may impinge on the adhesive and cause the die blade to become coated with adhesive and thereby cause problems. The adhesive can be of the releasable contact variety. The blade 
        
          
            64
          
        
         has a curvilinear cutting portion 
        
          
            66
          
        
        . The blade 
        
          
            64
          
        
         is pushed into the pack of bags and cuts out the curved aperture slits 
        
          
            34
          
        
        , 
        
          
            94
          
        
         in the tab portions 
        
          
            30
          
        
        , 
        
          
            92
          
        
        .
      
    
    
      
        When the blade 
        
          
            64
          
        
         and the stack of bags 
        
          
            12
          
        
        , 
        
          
            91
          
        
         are brought into contact with each other, the curvilinear cutting portion 
        
          
            66
          
        
         cleanly cuts the curved aperture slits 
        
          
            34
          
        
        , 
        
          
            94
          
        
        . This adhesive bonding contributes to the self-opening feature of the pack of bags, and also helps ensure that the thusly formed pack of bags is retained in stacked alignment for easy loading onto the bagging rack. The degree of frangible bonding formed in the handles can be increased by enlarging the surface contact area of the leading edge of sleeve member 
        
          
            72
          
        
        , such as by increasing the thickness of the blunt sleeve member 
        
          
            70
          
        
         and/or by increasing the die pressure exerted and the degree of corona treatment.
      
    
    
      
        A blade (not shown) is also used to form the handle holes 
        
          
            40
          
        
         and the surrounding area of frangible cold pressure bonding 
        
          
            41
          
        
         in the area near the handle holes 
        
          
            40
          
        
         for the embodiment of FIG. 
        
          
            1
          
        
        .
      
    
    
      
        
          FIG. 9
        
         illustrates another embodiment of a pack of T-shirt bags 
        
          
            110
          
        
         which are substantially the same as T-shirt bags 
        
          
            12
          
        
         in 
        
          FIGS. 1
        
         to 
        
          
            5
          
        
        , except for curved aperture slits 
        
          
            118
          
        
         replacing curved aperture slits 
        
          
            34
          
        
        .
      
    
    
      
        The T-shirt bag 
        
          
            110
          
        
         has a bottom edge 
        
          
            112
          
        
         and a tab portion 
        
          
            114
          
        
        . The tab portion 
        
          
            114
          
        
         has a top edge 
        
          
            116
          
        
         and a discontinuous curved aperture slit 
        
          
            118
          
        
        . Near the curved aperture slit 
        
          
            118
          
        
         are areas of frangible adhesive bonding 
        
          
            130
          
        
         similar to those of the embodiment of FIG. 
        
          
            1
          
        
        .
      
    
    
      
        Each curved aperture slit 
        
          
            118
          
        
         has a main cut section 
        
          
            120
          
        
         that is substantially parallel with bottom edges 
        
          
            112
          
        
         of the bag, a first discontinuous curved cut section 
        
          
            122
          
        
         coupled to one end of the main cut section, and a second curved cut section 
        
          
            124
          
        
         coupled to an opposite end of the main cut section. The first section 
        
          
            122
          
        
         curves to extend from the main cut section in a direction that is substantially perpendicular to the main cut section and towards the top edge 
        
          
            116
          
        
         of the tab portion 
        
          
            114
          
        
        . The first section 
        
          
            122
          
        
         is dashed, having a discontinuity 
        
          
            128
          
        
         in the slit 
        
          
            118
          
        
        , as described in more detail below. An end of the first section 
        
          
            122
          
        
         corresponds to a first end 
        
          
            136
          
        
         of the aperture slit 
        
          
            118
          
        
        .
      
    
    
      
        The second section 
        
          
            124
          
        
         is shaped as a semi-circle. The second curved section 
        
          
            124
          
        
         curves to extends from the main cut section 
        
          
            120
          
        
         in a direction towards the bottom edge 
        
          
            112
          
        
         of the tab portion 
        
          
            114
          
        
        . The second curved section 
        
          
            124
          
        
         has an end that is substantially perpendicular to and adjacent the main cut section.
      
    
    
      
        The discontinuity 
        
          
            128
          
        
         in the first section 
        
          
            122
          
        
         makes the tearing of a nick (not shown in this embodiment) from the slit 
        
          
            118
          
        
         to the top edge 
        
          
            116
          
        
         of the tab portion 
        
          
            114
          
        
         slightly more difficult. When the force is applied to the tab portion, the force is directed at tearing the nick. More force is used initially when the tear is started, but the force may be reduced after the tear is started. However, with the discontinuity 
        
          
            128
          
        
        , if the force is decreased after the initial tear, only the discontinuity 
        
          
            128
          
        
         disappears (the slit 
        
          
            118
          
        
         is then continuous). As a result, the force is again increased to a level sufficient to initiate the tearing from the end of the slit 
        
          
            118
          
        
         to the top edge 
        
          
            116
          
        
         of the tab portion 
        
          
            114
          
        
        .
      
    
    
      
        As shown in 
        
          FIG. 9
        
        , the tab portion 
        
          
            114
          
        
         has a first side 
        
          
            132
          
        
         adjacent the first curved section 
        
          
            122
          
        
        , and a second side 
        
          
            134
          
        
         adjacent the second curved section 
        
          
            124
          
        
        . A distance “x” between the first end 
        
          
            136
          
        
         of the aperture slit 
        
          
            118
          
        
         and the top edge 
        
          
            116
          
        
         of the tab is about 2 to 5 mm. A distance “y” between the second side 
        
          
            134
          
        
         and the first end 
        
          
            136
          
        
         of the aperture slit is about 5 to 8 cm. Generally, the greater the distances x and y, the greater the force that is applied to tear the tab to form the tearing nick (not shown) from the top edge 
        
          
            116
          
        
         of the tab portion to the aperture slit 
        
          
            118
          
        
        .
      
    
    
      
        
          FIG. 10
        
         illustrates another embodiment of a pack of merchandise bags 
        
          
            200
          
        
         which are substantially the same as the merchandise bags 
        
          
            90
          
        
         of 
        
          FIGS. 6
        
         to 
        
          
            7
          
        
        , except for curved aperture slits 
        
          
            118
          
        
         replacing the curved aperture slits 
        
          
            94
          
        
        . The bags 
        
          
            200
          
        
         have tab portions 
        
          
            202
          
        
         that each have the curved aperture slits 
        
          
            118
          
        
         as previously described with respect to FIG. 
        
          
            9
          
        
        .
      
    
    
      
        The self-opening mechanics for the embodiments of 
        
          FIGS. 6-7
        
        , 
        
          
            9
          
        
        , and 
        
          
            10
          
        
        , including the frangible adhesive bonding, are substantially the same as for the embodiment of the packs of self-opening T-shirt bags illustrated in 
        
          FIGS. 1-5
        
        , described above.
      
    
    
      
        
          FIG. 11
        
         illustrates a blade 
        
          
            140
          
        
         that is similar to the blade 
        
          
            64
          
        
         described with reference to FIG. 
        
          
            8
          
        
        . The blade 
        
          
            140
          
        
         is used to form the curved aperture slits 
        
          
            118
          
        
         of 
        
          FIGS. 9 and 10
        
        . The blade 
        
          
            140
          
        
         is similar to blade 
        
          
            64
          
        
        , in that it has a similarly shaped curvilinear cutting portion 
        
          
            142
          
        
        . However, the blade 
        
          
            140
          
        
         has a notch 
        
          
            144
          
        
         that is used to make the discontinuity 
        
          
            128
          
        
         in the aperture slit 
        
          
            118
          
        
        .
      
    
    
      
        The drawings and the foregoing description are not intended to represent the only form of the invention in regard to the details of this construction and manner of operation. In fact, it will be evident to one skilled in the art that modifications and variations may be made without departing from the spirit and scope of the invention.
      
    
    
      
        Although specific terms have been employed, they are intended in a generic and descriptive sense only and not for the purpose of limitation, the scope of the invention being delineated in the following the claims which follow.
      
    
  
             
            
                        Claims
        
                - 1. A pack of tabless self-opening bags for suspension on a bagging rack, comprising:a plurality of bags, each bag having a front wall having a bottom edge, a top edge, and side edges coupling the bottom edge and the top edge, wherein the top edge has a front tab that extends in a direction away from the bottom edge of the front wall; a rear wall having a bottom edge, a top edge, and side edges coupling the bottom edge and the top edge, wherein the top edge has a rear tab that extends in a direction away from the bottom edge of the front wall, each tab having a bottom edge that couples the tab with the top edge of the respective wall, a top edge opposite the bottom edge, a first side and a second side, wherein the bottom edge of the front wall is coupled with the bottom edge of the rear wall; side walls coupling the side edges of the front wall with the side edges of the rear wall; the tabs each having aperture slits formed therethrough which correspond to each other, the aperture slits being for suspension of the bag packs, the aperture slits having a general S-shape with a central portion and a first end and a second end, the first end being curved and extending generally upwardly and the second end being hook-shaped and being directed downwardly, inwardly, then upwardly towards the central portion, the aperture slits being adapted to tear through at the first end directly to in edge of the tab upon removable of a bag from the pack of bags and to retain the torn-through tab on the walls of the bag; and wherein contact adhesive is placed on the tabs between adjacent bags at least above and adjacent to the aperture slits to create a self-opening feature in the bag pack.
- 2. The pack of tabless self-opening bags of claim 1, wherein the contact adhesive is further located below the top edge of the front and rear walls.
- 3. The pack of tables self-opening bags of claim 1, wherein the bags further have handles that extend upwardly from side edges and straddle the tabs, the handles have apertures formed therethrough.
- 4. The pack of tabless self-opening bags of claim 3, wherein at least one of contact adhesive and frangible pressure bonding is additionally located adjacent to the apertures in the handles.
- 5. The pack of tabless self-opening bags of claim 1 wherein the aperture slit is dashed along the curved first end at least once.
- 6. The pack of tabless self-opening bags of claim 1 wherein a distance between the first end of the aperture slit and the top edge of the tab is about 2 to 5 mm.
- 7. The pack of tabless self-opening bags of claim 1 wherein the distance between the first end of the aperture slit and the second end of the aperture slit is about 5 to 8 cm.
- 8. The pack of tabless self-opening bags of claim 1, wherein the contact adhesive is further placed immediately below the central portion of the aperture slits and between the first curved end of the aperture slit and the first side of the tab.
- 9. The pack of tabless self-opening bags of claim 8, wherein the contact adhesive is applied as a plurality of spots.
- 10. A pack of tabless self-opening bags for suspension on a bagging rack, comprising:a plurality of bags, each bag having a front wall having a bottom edge, a top edge, and side edges coupling the bottom edge and the top edge, wherein the top edge has a front tab that extends in a direction away from the bottom edge of the front wall; a rear wall having a bottom edge, a top edge, and side edges coupling the bottom edge and the top edge, wherein the top edge has a rear tab that extends in a direction away from the bottom edge of the front wall, each tab having a bottom edge that couples that tab with the top edge of the respective wall, a top edge opposite the bottom edge, a first side and a second side, wherein the bottom edge of the front wall is coupled with the bottom edge of the rear wall; side walls coupling the side edges of the front wall with the side edges of the rear wall; the tabs each having aperture slits formed therethrough which correspond to each other, the aperture slits being for suspension of the bag packs, the aperture slits having a first end and a second end, the aperture slits being adapted to tear through at the first end directly to an edge of the tab upon removable of a bag from the pack of bags and retain the torn through tab on the walls of the bag; and wherein contact adhesive is placed on the tabs between adjacent bags adjacent to the aperture slits to create a self-opening feature in the bag pack.
US Referenced Citations (7)