Abstract:
A high strength plastic bag is formed from two sheets of polymeric material. The sheets are folded, machined, and heat sealed to form a receptacle portion, a flap for covering an opening to the receptacle portion and handles to facilitate handling of the bag when filled. At least one handle has three layers of polymeric material for improved strength. The bag includes a tamper-indicating closure and has a high friction coefficient to prevent sliding of stacked bags.

Description:
This application is a continuation-in-part of U.S. patent application Ser. No. 10/170,773 filed Jun. 13, 2002, now abandoned. 

   FIELD OF THE INVENTION 
   This invention relates to plastic bags, and more particularly to a high strength plastic bag. 
   BACKGROUND OF THE INVENTION 
   Plastic bags have been widely used to contain various articles. Such plastic bags include tamper-indicating bags, which have been used to secure sensitive or valuable items during transit. These tamper-indicating bags have often been used to transfer money in the form of paper money, checks, or coins. The use of plastic bags to transfer coins presents several problems, however. For example, when plastic bags are used to accommodate more than a small number of coins, the bags need to be strong so they do not rupture under the weight of the coins. To make carrying the bag easier, the plastic bags require a means for grasping the bag. Prior plastic bags having handles to permit a user to grasp the bags are limited with respect to the amount of coins which may be contained in the bag because the heavy weight of a large number of coins tends to tear the bag at the handle. Furthermore, conventional plastic bags are susceptible to sliding against one another, making it difficult to stack the bags atop one another. 
   Prior plastic coin bags have been provided with single handles for lifting the bags. However, the lifting of very heavy coin bags by a single person may cause excessive strain or injury to those handling the bags. In such instances, at least two persons may be required to lift and maneuver the coin bags. Unfortunately, grasping of the handle by two persons at the same time is generally very awkward and may even increase the potential for injury to handlers. 
   There is thus a need for a high strength plastic bag which may be used to contain and transport coins, and which overcomes the drawbacks of prior art plastic bags. 
   SUMMARY OF THE INVENTION 
   The present invention provides a high strength plastic bag which may be used to contain and carry heavy items, such as coins. In one embodiment, the bag is formed from two sheets of polymeric material which have been, folded, die stamped, and heat sealed to create a receptacle portion, handle portions, and a flap portion. Multiple handles on the bag facilitate lifting and handling by more than one person at a time. 
   The handle portions of the bag include apertures which permit users to grasp the bag, and at least one handle portion comprises three layers of high strength polymeric material that have been joined with heat seals to provide added strength to the handle. 
   The flap portion of the bag covers an opening to the receptacle and may be sealed over the opening with a tamper-evident adhesive to secure the bag. In one embodiment, the flap portion further includes a removable receipt which may be detached from the bag for record keeping purposes. In another embodiment, a second removable receipt is formed on a handle portion of the bag. 
   In yet another embodiment, the bag is formed from polymeric material having a high friction coefficient so that the bags may be stacked atop one another without slipping. 
   The features and objectives of the present invention will become more readily apparent from the following Detailed Description taken in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the invention. 
       FIG. 1  is a perspective view of an exemplary plastic bag of the present invention; 
       FIG. 2  is a cross-section of the bag shown in  FIG. 1 , taken along lines  2 - 2 ; 
       FIG. 3  is a perspective view of an alternative embodiment of a plastic bag of the present invention; 
       FIG. 4  is a cross-section of the bag of  FIG. 3 , taken along line  4 - 4  and depicting the bag in a sealed condition with first and second receipts detached from the bag; 
       FIG. 5  is a partial cross-section of the bag of  FIG. 1 , taken along line  5 - 5 ; 
       FIG. 6  is a perspective view of a third embodiment of a plastic bag according to the invention; 
       FIG. 6A  is a cross-sectional view of the bag of  FIG. 6 , taken along line  6 A- 6 A; 
       FIG. 7  is a perspective view of a fourth embodiment of a plastic bag according to the present invention; and 
       FIG. 7A  is a cross-sectional view of the bag of  FIG. 7 , taken along line  7 A- 7 A. 
   

   DETAILED DESCRIPTION 
   Referring to  FIGS. 1-2 , there is shown an exemplary plastic bag  10  of the present invention. The plastic bag  10  is formed from one or two sheets of plastic material  12 ,  14 . The first sheet  12  is folded in an overlapping manner and heat sealed to form an interior compartment. First sheet  12  is also folded together with the second sheet  14  to form a first handle for carrying the bag  10 . 
   As formed, the bag  10  includes a receptacle portion  16 , first and second handle portions  18 ,  19  and a flap portion  20 . The receptacle portion  16  of the bag  10  is formed by folding the first sheet  12  over itself to form a first folded edge  22  and first and second overlapping layers  24 ,  26 . The first handle portion  18  and the flap portion  20  of the bag  10  are formed by folding the first layer  24  of the first sheet  12  back over itself to create a second folded edge  36  whereby the free edge  38  of the first layer  24  extends beyond the free edge  34  of the second layer  26 . When the side edges  28 ,  30  of the folded sheet are heat sealed, the first and second layers  24 ,  26  of the first sheet  12  form a compartment  32  defined by the sealed edges  28 ,  30  and a lateral heat seal  74 . The interior of the compartment  32  may be accessed by an opening  33  created by the unsealed free edge  34  of the second layer  26 . 
   Handle portion  18  may further include a second plastic sheet  14  inserted between the folds of the first layer  24  of the first sheet  12  so that at least part of the first handle portion  18  comprises three layers of plastic. The first handle portion  18  further includes a first aperture  40  formed through the three layers of the first handle portion  18  at a distance from an end of the bag  10 . In an exemplary embodiment, the first aperture  40  is formed such that a peripheral edge of aperture  40  is approximately 2½ to 4 inches, and preferably approximately 3 inches from an end of the bag  10 . First handle portion  18  will generally include a heat seal around the perimeter of aperture  40 , and may further include a second reinforcing heat seal  41  around first aperture  40  and upper and lower heat seals  42 ,  44  above and below the first aperture  40  to join the three layers of plastic material. 
   The second sheet  14  of the first handle  18  is a polymeric sheet which has been developed for strength and heat sealability. It can be formed from standard polyolefins, blends or coextrusions. In an exemplary embodiment, the second sheet  14  has inner and outer layers formed from a blend of linear low density polyethylene and metalocene and a stiffening middle layer, such as high density polyethylene (HDPE). 
   The second handle portion  19  is formed near the first folded edge  22 , in a manner similar to the formation of the first handle portion  18 . A second aperture  70  is formed through the first and second overlapping layers  24 ,  26  and at a distance from the first folded edge  22 , whereby the distance between the first folded edge  22  and the nearest peripheral edge of the second aperture  70  is approximately 2½ to 4 inches, preferably 3 inches. As described above with respect to first aperture  40 , second aperture  70  will generally be heat sealed around its perimeter to join first and second layers  24 ,  26  at the aperture  70 . 
     FIGS. 3-4  depict an alternative embodiment of the present invention. In these drawings like numbers are used to identify like elements from  FIGS. 1 and 2 . Referring further to  FIGS. 3-4 , bag  10   a  includes second handle portion  19  having a second reinforcing heat seal  72  around the perimeter of second aperture  70 , as described above for first handle portion  18 . At least one lateral heat seal  74  joins the first and second overlapping layers  24 ,  26  in the vicinity of the second aperture  70 .  FIGS. 1-2  depict an exemplary bag  10  where second aperture  70  does not have a reinforcing heat seal  72  and only one lateral heat seal  74  is formed near the second aperture  70 .  FIGS. 3-4  depict an alternative exemplary bag  10   a , having a reinforcing seal  72  around the perimeter of second aperture  70 , and having two lateral heat seals  74  near second aperture  70 . 
   In the exemplary embodiment shown in  FIGS. 3-4 , an optional third sheet  76  of polymeric material is positioned between the first and second overlapping layers  24 ,  26 , such that the second aperture  70  is formed through the first and second overlapping layers  24 ,  26  and the third sheet  76  sandwiched therebetween. In this embodiment, the lateral heat seal  74  and the reinforcing seal  72  around the perimeter of the second aperture  70  join the three layers of plastic material  24 ,  26 ,  76  in the vicinity of the second aperture  70 . The third sheet  76  is formed from the same materials and in the same manner as the second sheet  14 , described above. 
   The flap portion  20  extends over the opening  33  formed by the free edge  34  of the second layer  26  of the first sheet  12  to form a closure for the bag. In the exemplary embodiment shown, the bag  10  is provided with an adhesive  46  applied to the second layer  26  of the first sheet  12  near the opening  33  created by the free edge  34 , whereby the flap  20  may be bonded to the second layer  26  to seal the bag  10 . A release liner  47  may be provided over the adhesive  46  to protect the adhesive  46  from contamination and to prevent premature bonding prior to sealing the bag  10 . 
   Preferably, the adhesive  46  is a tamper-indicating adhesive and the bag  10  is printed with tamper-indicating ink near the opening  33 , as described more fully in U.S. Pat. No. 6,196,716 to Geyer, incorporated by reference herein in its entirety. After the bag  10  is sealed as described above, the tamper-indicating adhesive  46  provides an indication of when the flap portion  20  has been opened the first time. In this manner, the plastic bag  10  provides a secure means for containing sensitive or valuable items. 
   In  FIG. 2A , an optional embodiment for sealing the bag  10  is shown an described. This optional sealing configuration can be used with any of the various bag embodiments shown and described herein. In this embodiment, flap  20  extends through opening  33  into the interior compartment  32  defined by the first and second layers  24 ,  26  of the folded first sheet  12 . Adhesive  46  is applied to the interiorly-facing side of the second layer  26  of first sheet  12 , near the opening  33  defined by free edge  34 , whereby flap  20  may be bonded to the second layer  26  to seal the bag. A release liner  47  may be provided over the adhesive  46  to protect the adhesive from contamination and to prevent premature bonding of the second layer  16  and flap  20  prior to sealing the bag, as described above. 
   Preferably, bag  10  further includes spot seals  78  at side edges  28 ,  30  near opening  33 , as shown in  FIGS. 1 ,  4  and  5 . Advantageously, spot seals  78  reinforce bag  10  at opening  33  to provide increased resistance to tearing at edges  28 ,  30  when flap  20  is pulled to reopen bag  10  after sealing with adhesive  46 . 
   The plastic bag  10  further includes one or more receipt portions  48 ,  50  which may be removed from the bag  10  for record keeping purposes. In the exemplary embodiments shown, bag  10  includes two receipt portions  48 ,  50  which may be removed from the bag  10 . A first receipt portion  48  is removably attached to the first handle portion  18  of the bag  10 , and a second receipt portion  50  is removably attached to the flap portion  20  of the bag  10 . In the exemplary embodiments, the receipt portions  48 ,  50  are formed by perforations  51 ,  52  formed on the bag  10  at a distance from the edges  36 ,  38  of the first handle  18  and flap portion  20  to create a removable strip of plastic material. It will be recognized, however, that the bag  10  may have only one removable receipt portion, or no receipt portions, and that the receipt portions may be provided on different parts of the plastic bag  10 . Ink or other visible material may be applied to the bag  10  to create viewable areas  54  for marking the bag  10  with indicia  56 . Such markable areas  54  are particularly useful on the receptacle and receipt portions  16 ,  48 ,  50 , but may be applied to any portion of the bag  10  as desired. 
   A high strength plastic bag  10  as described above may be formed from two sheets of plastic material  12 ,  14  according to the following exemplary method. The first sheet  12  of polymeric material is folded to form a first folded edge  22  and first and second overlapping layers  24 ,  26  whereby the first layer  24  extends beyond a free edge  34  of the second layer  26 . A second sheet  14  of polymeric material may be positioned on a portion of the first layer  24  of the first sheet  12 , at a distance from the free edge  34  of the second layer  26 . The first layer  24  of the first sheet  12  is folded over a portion of the second layer  26  of the first sheet  12 , forming a second folded edge  36  and a flap  20  which covers the free edge  34  of the second layer  26 . When second sheet  14  is positioned on first layer  24 , folding the first layer  24  over the second layer  26  sandwiches the second sheet  14  between the folds of the first layer  24 . 
   The first and second side edges  28 ,  30  of the first folded sheet  12  are heat sealed to define an interior compartment  32  between the first and second overlapping layers  24 ,  26  of the first sheet  12  and an opening  33  to the interior compartment  32  at the free edge  34  of the second layer  26 . The first sheet  12  of polymeric material is perforated near the second folded edge  36  to define a first removable receipt  48 . The first sheet  12  of polymeric material is perforated near the edge  38  of the flap  20  to define a second removable receipt  50 . 
   A first aperture  40  is formed through the folds of the first layer  24  of the first sheet  12  and through the second sheet  14  sandwiched between the folds of the first sheet  12 , so that a peripheral edge of aperture  40  is approximately 2.5 to 4 inches from the perforation defining the first removable receipt  48 . A second aperture  70  is formed near first folded edge  22  at a distance of approximately 2.5 to 4 inches from the first folded edge  22 . In an exemplary method, first and second sheets  12 ,  14  are sealed with a reinforcing heat seal around the perimeter of first aperture  40  and at locations  42 ,  44  above and below first aperture  40 . 
   In another exemplary method, first and second overlapping layers  24 ,  26  are heat sealed around the perimeter of second aperture  70 , and at least one lateral heat seal  74  is formed to join first and second overlapping layers  24 ,  26  in the vicinity of second aperture  70 . 
   In yet another exemplary method, a third sheet  76  of polymeric material is positioned between the first and second overlapping layers  24 ,  26 , such that the second aperture  70  is formed through the first and second overlapping layers  24 ,  26  and the third sheet  76  sandwiched therebetween. In this embodiment, the lateral heat seal  74  and the reinforcing seal  72  around the perimeter of the second aperture  70  are formed to join the three layers of plastic material  24 ,  26 ,  76  in the vicinity of the second aperture  70 . 
   Indicia  56  may be printed on any portion of the plastic bag  10  either before or after formation of the bag  10 . In an exemplary embodiment, ink  60  is applied to portions of the first sheet  12  near the side edges  28 ,  30  and the opening  33  formed by the free edge  34  of the second layer  26  of the first sheet  12 . The ink  60  applied in these areas prevents the flap portion  20  of the bag  10  from sealing against the bag  10  when the bag  10  is formed. 
   Advantageously, the second handle portion  19  permits bag  10  to be easily grasped and handled by two persons. This is especially useful when a bag  10  is filled with heavy items, such as a large quantity of coins, and it is necessary or desirable for two persons to handle the bag  10 . 
     FIGS. 6 and 6A  depict yet another exemplary plastic bag  10   b  according to the present invention. Plastic bag  10   b  is similar in many respects to the plastic bags  10 ,  10   a  discussed above with respect to  FIGS. 1-5 , and similar features have been similarly numbered. In particular, plastic bag  10   b  is formed from two sheets of plastic material  12 ,  14  folded and heat sealed as described above. Alternatively, bag  10   b  may be formed using only a single sheet of plastic material  12 , folded and heat sealed as described above. 
   Bag  10   b  includes a receptacle portion  16 , a handle portion  18 , and a flap portion  20 . The receptacle portion  16  is formed by folding the first sheet  12  over itself to form first folded edge  22  and first and second overlapping layers  24 ,  26 , as described above. The handle portion  18  and the flap portion  20  are formed by folding first layer  24  of the first sheet  12  back over itself to create a second folded edge  36  such that the free edge  38  of the first layer  24  extends beyond the corresponding free edge  34  of the second layer  26 . The handle portion  18 , above the receptacle portion  16 , includes first and second spaced-apart apertures  40   a ,  40   b  formed through the first and second layers  24 ,  26 . When it is desired to further increase the strength of the handle portion  18 , a second plastic sheet  14  may be inserted between the folds of the first layer  24  of the first sheet  12  such that at least part of the handle portion  18  comprises three layers of plastic material. First handle portion  18  will generally include heat seals around the perimeter of the apertures  40   a ,  40   b , and may further include second reinforcing heat seals  41   a ,  41   b  around the apertures  40   a ,  40   b , and upper and lower heat seals  42 ,  44  positioned above and below the apertures  40   a ,  40   b.    
   Plastic bag  10   b  further includes a first receipt portion  48  removably attached to the handle portion  18 , and a second receipt portion  50  removably attached to the flap portion  20 , similar to plastic bags  10 ,  10   a  discussed above. In these embodiments, the receipt portions  48 ,  50  are formed by perforations  51 ,  52  formed into the bag  10   b  at distances spaced from respective edges  36 ,  38  of the handle portion  18  and flap portion  20  to create removable strips of plastic material. 
   Other features of plastic bag  10   b  are similar to those described above with respect to plastic bags  10 ,  10   a . The first and second apertures  40   a ,  40   b  on the handle portion  18  facilitate grasping and carrying the plastic bag  10   b  by two hands of a user, or alternatively two different users may each grasp one of the apertures  40   a ,  40   b  to cooperatively carry a filled bag  10   b.    
   Referring now to  FIGS. 7 and 7A , there is shown yet another embodiment of a plastic bag  10   c  according to the present invention. Plastic bag  10   c  includes many features in common with plastic bags  10 ,  10   a ,  10   b  shown and described above, and these similar features are similarly numbered. In particular, plastic bag  10   c  comprises a receptacle portion  16 , a handle portion  18  and a flap portion  20 . The receptacle portion is formed by folding a first sheet  12  of plastic material over itself to form a first folded edge  22  and first and second overlapping layers  24 ,  26 . The receptacle portion is formed from at least a portion of the first and second overlapping layers  24 ,  26  which define first and second opposing walls and an interior cavity  32  for receiving articles through opening  33 , as described above. 
   First layer  24  of the first sheet  12  is folded back over itself to create a second folded edge  36  having a free edge  38  that extends beyond the free edge  34  of the second layer  26  to thereby define a first handle portion  18  and a flap portion  20 . An aperture  40  is formed through the first handle portion  18  so that a peripheral edge of aperture  40  is spaced from the end of the bag and generally includes a heat seal around its parameter. If it is desired to further increase the strength of the first handle portion  18 , a second plastic sheet  14  may be inserted between the folds of the first layer  24  of the first sheet  12  such that at least a part of the first handle portion  18  comprises three layers of plastic material. First handle portion  18  may further include a second reinforcing heat seal  41  around the aperture  40  and upper and lower heat seals  42 ,  44  positioned above and below the aperture  40 . 
   Plastic bag  10   c  further includes first and second removable receipt portions  48 ,  50  removably attached to the first handle portion  18  and the flap portion  20 , respectively and defined by perforations  51 ,  52  formed into the bag  10 , as described above. It will be recognized, however, that the bag  10   c , as well as any of the other bag embodiments of the present invention, may have only one removable receipt portion, or no receipt portions, and that the receipt portions may be provided on various other parts of the plastic bag  10   c.    
   Plastic bag  10   c  further includes a second handle portion  80  comprising an elongate strip  82  of plastic material having distal ends  84 ,  86  joined to at least one of the first and second layers  24 ,  26  to define a loop intermediate the distal ends  84 ,  86 . In the embodiment shown, the distal ends  84 ,  86  are heat sealed along side edges  28 ,  30  of the receptacle portion  16 , and the second handle portion  80  is positioned at an end of the bag  10   c  generally opposite first handle portion  18 . It will be recognized, however, that second handle portion  80  may alternatively be joined to other portions of the first sheet  12  such as along only one of the side edges  28 ,  30 , a position intermediate respective folded edges  22 ,  36 , or at a position overlapping first handle portion  18 , for example. 
   While the elongate strip of plastic material  82  has been shown and described joined to first sheet  12  by heat sealing, it will be recognized that the elongate strip  82  may alternatively be joined to the first sheet  12  by other methods, such as by adhesives, fasteners or any other method suitable for securing the elongate strip  82  to the bag  10   c  to define the second handle portion  80 . The loop defined by second handle portion  80  may be used like a shoulder strap to facilitate carrying a filled plastic bag  10   c . Alternatively, plastic bag  10   c  may be carried by two persons, whereby a first person grasps the first handle portion  18  through aperture  40 , and a second person grasps second handle portion  80 . 
   While the present invention has been illustrated by the description of the various embodiments thereof, and while the embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of applicant&#39;s general inventive concept.