Patent Abstract:
A roll of plastic bags having integral handles which can also be used to close each bag. The bags are formed as a continuous web of folded and flattened bags each joined to a longitudinally contiguous bag by a perforated severance line. The handles are defined by a cut-out region so that separation of the bags is effected by tearing the line of perforations only across a relatively short length.

Full Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention relates to plastic bags which are provided on a roll to be dispensed one at a time and, more particularly, to such a bag which is formed with unitary handles which are also usable for closing the bag. 
         [0002]    Conventionally, plastic bags used for holding trash or the like are manufactured by extruding a tube of plastic material, expanding the tube with air before the plastic has set, flattening the tube, forming transverse heat seals and adjacent perforations at equally spaced intervals, and longitudinally folding and/or rolling up the flattened tube for storage and transport in a dispensing carton. The bags are removed one at a time from the dispensing carton by tearing them off the roll at the perforations. 
         [0003]    When such a bag is filled, it is necessary to close it by utilizing a separate tie. The use of a separate tie is disadvantageous for a number of reasons. It is necessary to hold the bag closed with one hand while applying the tie with the other hand. The ties must be stored separately and can be misplaced. With overly full bags, the ties may be difficult to apply. 
         [0004]    Various bag constructions have been proposed which incorporate integral tie strips. These constructions also possess numerous drawbacks. They require an additional act on the part of the user to tear away the integral tie strip from the remainder of the bag. They also reduce the useful capacity of the bag. 
         [0005]    All of these constructions also require that the user separate the bags by tearing the line of perforations across the entire width of the bag. When pulling a bag from a dispenser carton, this can pose difficulty for a user. 
         [0006]    It would therefore be desirable to have a bag construction which overcomes all of the drawbacks of these prior constructions. 
       SUMMARY OF THE INVENTION 
       [0007]    According to the present invention there is provided a roll of plastic bags formed as a continuous web of folded and flattened bags each joined to a longitudinally contiguous bag by a perforated severance line. The web is formed from a tubular plastic strip having a central longitudinal axis and the sides of the strip are tucked in to form two equal inward folds, reducing the width of the strip by one half. The reduced width strip is folded in half along the central longitudinal axis so that there are eight layers of plastic material. The perforated severance lines are parallel one to the other, are equally spaced along the strip and are orthogonal to the central longitudinal axis of the strip. A pair of parallel heat seal lines flank each of the severance lines. A first of the heat seal lines extends through all eight layers of the plastic material and a second of the heat seal lines is formed of two heat seal lines each of which extends through a respective four contiguous layers of the plastic material. Finally, there is a cut-out region through the eight layers which extends from the central longitudinal axis along each severance line a first predetermined distance and then substantially parallel to the central longitudinal axis a second predetermined distance past the second heat seal line and then back to the central longitudinal axis. Accordingly, each first heat seal line is effective to seal the bottom of a respective bag, and each cut-out region and respective adjacent second heat seal line is effective to form a pair of handles of a respective bag. 
         [0008]    In accordance with an aspect of this invention, the first predetermined distance is greater than one-half the width of the reduced width strip after it has been folded in half. 
         [0009]    In accordance with another aspect of this invention, the second predetermined distance is greater than the first predetermined distance. 
         [0010]    According to this invention, there is provided a plastic bag formed from a folded tubular plastic strip. The plastic bag comprises a closed bottom end including a heat seal line extending through eight layers of folded plastic strip, and an open top end having a pair of spaced handles. Each of the handles has a respective heat seal line extending through a respective four contiguous layers of folded plastic strip and the handles are separated by a cut-out region so that the handles extend past an opening in the top end of the bag. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The foregoing will be more readily apparent upon reading the following description in conjunction with the drawings in which like elements in different figures thereof are identified by the same reference numeral and wherein: 
           [0012]      FIG. 1  is a perspective view showing a partially open bag constructed according to the present invention; 
           [0013]      FIG. 2  is a plan view showing a portion of a roll of a continuous web of bags according to the present invention; 
           [0014]      FIG. 3  is a sectional view taken along the line  3 - 3  in  FIG. 2 ; 
           [0015]      FIGS. 4 ,  6 ,  8  and  10  illustrate steps during the manufacture of the inventive bags; and 
           [0016]      FIGS. 5 ,  7  and  9  are sectional views taken along the lines  5 - 5 ,  7 - 7  and  9 - 9  in  FIGS. 4 ,  6  and  8 , respectively. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    As shown in  FIG. 1 , the inventive plastic bag  20  has a bottom end  22  and a transverse heat seal line  24  adjacent the bottom end  22 . At the opposite end of the bag  20 , there is an open top end  26  including a pair of handles  28 , 30 , each with a respective transverse heat seal line  32 , 34 . As will become clear from the following discussion, the heat seal line  24  extends through eight layers of the plastic material forming the bag  20  and each of the heat seal lines  32 , 34  extends through a respective four contiguous layers of the plastic material. The handles  28 , 30  can be tied together to close the open top end  26  of the bag  20 , in addition to their use in assisting a user in holding the bag  20 . 
         [0018]      FIG. 2  shows a plurality of inventive bags  20  which have not yet been separated one from the other and which are wound into a roll  36 . The bags  20  are joined by, and may be separated at, lines of perforations  38  between the heat seal lines  24  and  32 , 34 . As is clear from  FIG. 3 , when the bag  20  is on the roll  36  and as it is unrolled from the roll  36 , the bag  20  is folded to have eight layers of plastic material. 
         [0019]      FIGS. 4-10  illustrate steps in the formation of the bag  20 . As shown in  FIGS. 4 and 5 , the bag starts as a continuous endless tubular plastic strip  40  traveling in the direction of the arrow  42 . The strip  40  may be considered to have a central longitudinal axis  44  which is parallel to the direction arrow  42 . The first step in the formation of the bag  20  is to tuck in the two side edges  46 , 48  of the strip  40  to form two equal inward folds and reduce the width of the strip  40  by one half, as shown in  FIGS. 6 and 7 . 
         [0020]    The strip  40  then passes through a first sealing and cutting mechanism (not shown) which forms the heat seal lines  32  and  34  and the cut-out region  50 . The heat seal lines  32  and  34  are co-linear (they are preferably formed in a single step) and transverse (preferably orthogonal) to the central longitudinal axis  44 . Each of the heat seal lines  32  and  34  extends through a respective four contiguous layers of the plastic material of the strip  40 , as is clear from  FIGS. 8 and 9 . The cut-out region  50  is substantially rectangular and extends in two directions away from the central longitudinal axis  44  substantially orthogonally thereto a first predetermined distance “a” along the line  22 , and then substantially parallel to the axis  44  a second predetermined distance “b” past the heat seal lines  32  and  34 , and then back to the axis  44  along the line  26  orthogonally to the axis  44 . Preferably, the first predetermined distance from the axis  44  along the line  22  is greater than one-half the width of the strip  40  after the side edges  46 , 48  have been tucked in. Also preferably, the second predetermined distance (i.e., the distance between the lines  22 , 26 ) is greater than the first predetermined distance. 
         [0021]    The final step in the formation of the bag  20  is illustrated in  FIG. 10 . As shown therein, the strip  40  is folded in half along the central longitudinal axis  44  so that it comprises eight layers of plastic material. The strip  40  then passes through a second sealing and cutting mechanism (not shown) which forms the heat seal line  24  and the line of perforations  38 , both of which extend through all eight layers of the strip  40 . The heat seal line  24  and the line of perforations  38  are both transverse to the axis  44  and preferably are orthogonal thereto. The line of perforations  38  is between the heat seal lines  24  and  32 , 34  and is aligned with the line  22  of the cut-out region  50 . After this final formation step, the finished strip  40  is rolled up to form the roll  36 , which may comprise a desired number of bags  20 . On the roll  36 , the bags are so configured that the bottom end  22  of each bag is further into the roll  36  than the top end  26 . The roll  36  may then be placed into an appropriate carton for storage, shipment and dispensing. 
         [0022]    In use, a bag  20  is pulled from the roll  36  by the handles  28 , 30  until the line of perforations  38  at its bottom end  22  is exposed. The bag which was pulled from the roll is then separated from the next bag in the roll by tearing along the line of perforations  38 . An advantage of the disclosed construction is that only a relatively short line of perforations needs to be severed, due to the cut-out region  50 , which is also effective to provide separate handles  28 , 30 . 
         [0023]    Accordingly, there has been disclosed an improved roll of plastic bags. While a preferred embodiment of the inventive plastic bag has been disclosed, it will be appreciated by those of skill in the art that various adaptations and modifications to the disclosed bag are possible. It is therefore intended that this invention be limited only by the scope of the appended claims.

Technology Classification (CPC): 1