Patent Document

RELATED APPLICATIONS 
     The instant application is a divisional of U.S. application Ser. No. 13/566,491, filed Aug. 3, 2012 and currently pending, which is a continuation of U.S. application Ser. No. 13/101,946, filed May 5, 2011, issued as U.S. Pat. No. 8,317,670, which is a divisional of U.S. application Ser. No. 11/829,017, filed Jul. 26, 2007, issued as U.S. Pat. No. 7,963,898. 
    
    
     FIELD OF INVENTION 
     The invention pertains to plastic film produce bags. More particularly, the invention relates to plastic produce bags having no bottom seam and to methods for making the bags. The lack of a bottom seam provides for increased resistance to rupturing. Further, these bags are folded in thirds across their side seams to permit dispensing from a compact roll dispenser. 
     BACKGROUND OF THE INVENTION 
     Various designs have been developed for plastic produce bags as well as for methods for making and dispensing the bags. 
     U.S. Pat. No. 5,611,627 issued to Belias et al. is directed to an easy open thermoplastic bag. The bag is manufactured from a flattened tube of thermoplastic material with transverse heat seals. The transverse heat seals along with the sinusoidally oscillating paths form the tube into two halves or bags. The result of the transverse heat-seals and the cutting paths, is that two bags are formed with seamless bottoms. The sinusoidal cuts in the front and back portions of the tube respectively give rise to a mouth or opening for the bags with tabs that allow for the bags to be more easily opened. 
     U.S. Pat. No. 4,164,170 issued to Nordin, discloses a method of making bags. The Patent describes the manufacturing of a string of bags from a hose-like blank. Since a hose-like blank is used, the bottoms of the resultant bags are continuous in nature and the sides of a bag are formed by welds with separation lines in order to separate one set of bags from another. The hose-like blank is cut into two substantially equal parts along a center line while the cutting lines are offset to form the handles of the finished bag. 
     U.S. Pat. No. 4,811,418, issued to Reifenhauser is directed to a method for the manufacture of plastic bags with welded side seams. The patent describes the production of two bags side-by-side in parallel from tubular film that is fed in a first direction. The tubular film is cut in a sinusoidal configuration in the center of the film, thus forming two semitubes to form two side seam bags with welded side seams and handle opening portions. 
     U.S. Pat. No. 2,444,685 issued to Waters is directed to the multiple fabrication method and apparatus for forming liquid-type envelope bags. A supply roll of material with defined edges is passed through feed rolls and around a former plate in order to bring the edges together along a line with a defined space between them. The edges ultimately form the opening of the envelope after having been cut by a cutter into separate envelopes. A pair of transverse welds are formed in the process and the paired envelopes are cut by means of cross-cut knife. 
     U.S. Pat. No. 5,967,663 issued to Vaquero et al. is directed to a thermoplastic bag structure. The thermoplastic tube is cut into two portions by means of cutting instruments that form sinusoidal paths and hence sinusoidal cuts. Transverse heat seals and transverse perforations separate the tube into pairs of bags such that the folded bottom edge does not require heat sealing and the openings of the resultant bags have “tabs” so that they may be more easily opened. 
     U.S. Pat. No. 6,488,222, issued to West et al., describes A folded gusseted plastic bag has a first side gusset formed by first, second, and third longitudinal folds, a second side gusset formed by fourth, fifth, and sixth longitudinal folds, a seventh longitudinal fold being on a side of the bag containing the first, second, and third folds and forming a first folded bag flap, and an eighth longitudinal fold which is on a side of the bag containing the fourth, fifth, and sixth folds, the eighth fold forming a second folded bag flap. The folded gusseted bag also is folded into a total of at least eight contiguous plies. A roll of the folded, gusseted bags includes a continuous web of the folded, flattened bags joined along perforated severance lines. Preferably the perforated severance lines further comprise a centrally-located slit. The dispensing system utilizes the roll of folded-gusseted bags in combination with a dispenser comprising: (i) a support member for attachment to a support surface; (ii) a pair of guide channels carried by the support member for rotatably supporting the roll of plastic bags for rotation of the roll on the core; (iii) a tongue spaced apart from and carried by said support member in a predetermined position corresponding to the predetermined position of the slit in the tear line. 
     U.S. Pat. No. 6,379,292, issued to Simhaee, illustrates a continuous web of bags formed of a plurality of layers to be separated along a line of perforations that extends through all of the layers transverse of the web, in which at least one of the outermost layers is detached from the web at the separation line. Apparatus accomplishes this detachment in a moving web by engaging the outermost layer outer surface and exerting a force in a manner to produce the detachment from the separation line. Both the outermost upper and lower web layers can be detached at the separation line. 
     U.S. Pat. No. 5,967,663, issued to Vaquero et al., discloses a thermoplastic bag structure and method for making and packaging thermoplastic bags such that their tops are easily identified and the bags are easily opened. The method for producing these bags begins with cutting a flattened thermoplastic tube into two portions. At least one of the two portions is then collapsed to form a sheet of material having a pair of thermoplastic layers, a straight folded bottom edge and a pair of top edges, at least one of which has a skewed-cut. Bag side structures are formed in the sheet of material at about bag-width distances apart. The bags are then folded a predetermined number of times, in a direction transverse to the bag side structures, so that the skewed-cut top edge(s) of each of the bags remains exposed. 
     While other variations exist, the above-described designs for plastic produce bags are typical of those encountered in the prior art. It is an objective of the present invention to provide a produce bag without a bottom seam for additional strength in the bag bottom. It is a further objective to provide a produce bag that provides means to easily identify and open the bag. It is a still further objective of the invention to provide the above-described capabilities in a produce bag that can be easily dispensed from a roll using a compact and inexpensive dispenser. It is a further objective to provide bags that can be formed into compact rolls on cores or without cores. It is yet a further objective to provide a means to manufacture such produce bags using economical and reliable high-speed methods. While some of the objectives of the present invention are disclosed in the prior art, none of the inventions found include all of the requirements identified. 
     SUMMARY OF THE INVENTION 
     The present invention addresses all of the deficiencies of side-seamed plastic produce bag inventions and satisfies all of the objectives described above. 
     (1) A trifold side-seamed plastic produce bag providing the desired features may be constructed from the following components. A front wall is provided. The front wall has a top edge, a bottom edge, a first side edge, a second side edge and a first predetermined height. A back wall is provided. The back wall has an upper edge, a lower edge, a first side edge, a second side edge and a second predetermined height greater than the first predetermined height. The front wall and the back wall are formed from a single piece of plastic film such that the bottom edge of the front wall is joined seamlessly with the lower edge of the back wall. 
     The first side edge of the front wall is attached to the first side edge of the back wall at a first side seam. The second side edge of the front wall is attached to the second side edge of the back wall at a second side seam. A perforation is provided. The perforation is spaced from the second side seam and extends from the upper edge of the back wall to the lower edge of the back wall. The perforation joins the bag to a subsequent bag. First and second fold lines are provided. The first and second fold lines are parallel to the upper and lower edges and spaced from the upper and lower edges, respectively, by approximately one third of the second predetermined height. When separated from the subsequent bag, the bag will have a back wall of greater height than the front wall, thereby providing a means for locating an opening of the bag. 
     (2) A method of making trifold side-seamed plastic produce bags, comprises the steps of: extruding a continuous tube of plastic film and flattening the tube. The tube has an upper surface, a lower surface, first and second side edges. Slitting the upper surface to remove a strip of plastic material to form a cut. The cut has a first side and a second side. The first and second sides are parallel to the first and second side edges of the tube. Removing the strip. Forming a perforation perpendicular to the first and second side edges across an entire width of the tube. Sealing the tube at a first side seam. The first side seam is spaced from and parallel to the perforation. Sealing the tube at a second side seam. The second side seam is spaced from and parallel to the first side seam. Cutting the lower surface at a point below and between the first and second sides of the slit in the upper surface to form two facing bag streams, each of said bag streams having a first predetermined width. Folding each of the bag streams to approximately one third of the first predetermined width. 
     (3) In a variant of the method of making trifold side-seamed plastic produce bags, the method includes the further step of corona treating at least one of the upper surface and the lower surface of the flattened tube prior to slitting the upper surface to remove the strip of plastic material. 
     (4) In a further variant of the method includes the further step of printing advertising or informational material on at least one of the corona treated surfaces of the flattened tube. 
     (5) In still a further variant of the method includes the further step of rolling each of the bag streams to form a bag roll. 
     (6) In yet a further variant of the method includes the further step of rolling each of the bag streams about a cylindrical core to form a bag roll. 
     (7) In another variant of the method, each of the bag streams is folded in a Z-fold configuration. 
     (8) In still another variant of the method, each of the bag streams is folded in a Z-fold configuration. 
     (9) In another variant of the method of making trifold side-seamed plastic produce bags, the method includes the steps of: Extruding a continuous tube of plastic film and flattening the tube. The tube has an upper surface, a lower surface, first and second side edges. Winding the flattened tube onto a core. Moving the core to a cutting machine. The cutting machine includes a slitter. Feeding the tube from the core into the cutting machine. Slitting the upper surface to remove a strip of plastic material to for a cut. The cut has a first side and a second side. The first and second sides are parallel to the first and second side edges of the tube. Removing the strip. Forming a perforation perpendicular to the first and second side edges across an entire width of the tube. Sealing the tube at a first side seam. The first side seam is spaced from and parallel to the perforation. Sealing the tube at a second side seam. The second side seam is spaced from and parallel to the first side seam. Cutting the lower surface at a point below and between the first and second sides of the slit in the upper surface to form two facing bag streams, each of said bag streams having a first predetermined width. Folding each of the bag streams to approximately one third of the first predetermined width. 
     (10) In a further variant of the method of making trifold side-seamed plastic produce bags, the method includes the further step of corona treating at least one of the upper surface and the lower surface of the flattened tube prior to slitting the upper surface to remove the strip of plastic material. 
     (11) In still a further variant of the method includes the further step of printing advertising or informational material on at least one of the corona treated surfaces of the flattened tube. 
     (12) In yet a further variant of the method includes the further step of rolling each of said bag streams to form a bag roll. 
     (13) In another variant of the method includes the further step of rolling each of said bag streams about a cylindrical core to form a bag roll. 
     (14) In still another variant of the method, each of said bag streams is folded in a Z-fold configuration. 
     (15) In yet another variant of the method, each of said bag streams is folded in a C-fold configuration. 
     (16) In a further variant of the method of making trifold side-seamed plastic produce bags, the method includes the steps of: Extruding a continuous tube of plastic film and flattening the tube. The tube has an upper surface, a lower surface, first and second side edges. Corona treating at least one of the upper surface and the lower surface of the flattened tube. Slitting the upper surface to remove a strip of plastic material to form a cut. The cut has a first side and a second side. The first and second sides are parallel to the first and second side edges of the tube. Removing the strip. Printing either advertising or informational material on at least one of the corona treated surfaces of the flattened tube. Forming a perforation perpendicular to the first and second side edges across an entire width of the tube. Sealing the tube at a first side seam spaced from and parallel to the perforation. Sealing the tube at a second side seam. The second side seam is spaced from and parallel to the first side seam. Winding the tube onto a core for later cutting of the lower surface at a point below and between the first and second sides of the cut in the upper surface to form two facing bag streams, each of said bag streams having a first predetermined width. Folding each of said bag streams to approximately one third of said first predetermined width. 
     (17) In still a further variant of the method of making trifold side-seamed plastic produce bags, the method includes the step of rolling each of said bag streams to form a bag roll. 
     (18) In another variant of the method of making trifold side-seamed plastic produce bags, the method includes the step of rolling each of said bag streams about a cylindrical core to form a bag roll. 
     (19) In still another variant of the method, each of said bag streams is folded in a Z-fold configuration. 
     (20) In yet another variant of the method, each of said bag streams is folded in a C-fold configuration. 
     (21) In still another variant of the method of making trifold side-seamed plastic produce bags, the method includes the steps of: Extruding a continuous tube of plastic film and flattening the tube. The tube has an upper surface, a lower surface, first and second side edges. Corona treating at least one of the upper surface and the lower surface of the flattened tube. Printing either advertising or informational material on at least one of the corona treated surfaces of the flattened tube. Slitting the upper surface to remove a strip of plastic material to form a cut. The cut has a first side and a second side. The first and second sides are parallel to the first and second side edges of the tube. Removing the strip. Forming a perforation perpendicular to the first and second side edges across an entire width of the tube. Sealing the tube at a first side seam spaced from and parallel to the perforation. Sealing the tube at a second side seam. Folding each of said bag streams to approximately one third of said first predetermined width. The second side seam is spaced from and parallel to the first side seam. Winding the tube onto a core for later cutting of the lower surface at a point below and between the first and second sides of the cut in the upper surface to form two facing bag streams, each of said bag streams having a first predetermined width. Folding each of said bag streams to approximately one third of said first predetermined width. 
     (22) In a further variant of the method, the method includes the further step of rolling each of the bag streams to form a bag roll. 
     (23) In still a further variant of the method, the method includes the further step of rolling each of the bag streams about a cylindrical core to form a bag roll. 
     (24) In still another variant of the method, each of said bag streams is folded in a Z-fold configuration. 
     (25) In yet another variant of the method, each of said bag streams is folded in a C-fold configuration. 
     (26) An apparatus for making tri-fold side-seamed plastic produce bags includes the following components. A supply of thermoplastic resin is provided. An extruder is provided. The extruder is capable of extruding a continuous tube of thermoplastic film. A tubing flattener is provided. The flattener is capable of flattening the tube. The tube has an upper surface, a lower surface, first and second side edges. A cutting machine is provided. The cutting machine is capable of slitting the upper surface to remove a strip of plastic material to form a cut. The cut has a first side and a second side. The first and second sides are parallel to the first and second side edges of the tube. A perforator is provided. The perforator is capable of forming a perforation perpendicular to the first and second side edges across an entire width of the tube. A sealer is provided. The sealer is capable of sealing the tube at a first side seam spaced from and parallel to the perforation and at a second side seam spaced from and parallel to the first side seam. A slitter is provided. The is slitter capable of cutting the lower surface at a point below and between the first and second sides of the cut in the upper surface to form two facing bag streams. Each of the bag streams has a first predetermined width. A folder is provided. The folder is capable of folding each of the bag streams to approximately one third of the first predetermined width. 
     (27) In another variant of the apparatus, a corona treater is provided. The corona treater is capable of corona treating at least one upper and lower surface of the tube prior to folding. 
     (28) In still another variant, a printer is provided. The printer capable of printing advertising or informational material on at least one of the corona treated surfaces of the flattened tube. 
     (29) In yet another variant, a bag rolling device is provided. The bag rolling device is capable of rolling each of the bag streams to form a bag roll. 
     (30) In a further variant, a supply of cores is provided. Each of the bag streams is wound around one of the cores to form the bag rolls. 
     (31) In still a further variant, the folder is capable of folding each of the bag streams in a Z-fold configuration. 
     (32) In yet a further variant, the folder is capable of folding each of the bag streams in a C-fold configuration. 
     (1) A trifold side-seamed plastic produce bag providing the desired features may be constructed from the following components. A front wall is provided. The front wall has a top edge, a bottom edge, a first side edge, a second side edge and a first predetermined height. A back wall is provided. The back wall has an upper edge, a lower edge, a first side edge, a second side edge and the first predetermined height. The front wall and the back wall are formed from a single piece of plastic film such that the bottom edge of the front wall is joined seamlessly with the lower edge of the back wall. 
     The first side edge of the front wall is attached to the first side edge of the back wall at a first side seam. The second side edge of the front wall is attached to the second side edge of the back wall at a second side seam. A perforation is provided. The perforation is spaced from the second side seam and extends from the upper edges of the front and the back walls to the lower edge. The perforation joins the bag to a subsequent bag. First and second fold lines are provided. The first and second fold lines are parallel to the upper and lower edges and spaced from the upper and lower edges, respectively, by approximately one third of the first predetermined height. When separated from the subsequent bag, the bag will have a front wall and a back wall of substantially identical height. 
     (2) A method of making trifold side-seamed plastic produce bags, comprises the steps of: extruding a continuous tube of plastic film and flattening the tube. The tube has an upper surface, a lower surface, first and second side edges. Forming a perforation perpendicular to the first and second side edges across an entire width of the tube. Sealing the tube at a first side seam. The first side seam is spaced from and parallel to the perforation. Sealing the tube at a second side seam. The second side seam is spaced from and parallel to the first side seam. Cutting the upper surface and the lower surface to form two facing bag streams, each of said bag streams having a first predetermined width. Folding each of the bag streams to approximately one third of the first predetermined width. 
     (3) In a variant of the method of making trifold side-seamed plastic produce bags, the method includes the further step of corona treating at least one of the upper surface and the lower surface of the flattened tube. 
     (4) In a further variant of the method includes the further step of printing advertising or informational material on at least one of the corona treated surfaces of the flattened tube. 
     (5) In still a further variant of the method includes the further step of rolling each of the bag streams to form a bag roll. 
     (6) In yet a further variant of the method includes the further step of rolling each of the bag streams about a cylindrical core to form a bag roll. 
     (7) In another variant of the method, each of the bag streams is folded in a Z-fold configuration. 
     (8) In still another variant of the method, each of the bag streams is folded in a C-fold configuration. 
     (9) In a further variant of the method of making trifold side-seamed plastic produce bags, the method includes the steps of: Extruding a continuous tube of plastic film and flattening the tube. The tube has an upper surface, a lower surface, first and second side edges. Corona treating at least one of the upper surface and the lower surface of the flattened tube. Printing either advertising or informational material on at least one of the corona treated surfaces of the flattened tube. Forming a perforation perpendicular to the first and second side edges across an entire width of the tube. Sealing the tube at a first side seam spaced from and parallel to the perforation. Sealing the tube at a second side seam. The second side seam is spaced from and parallel to the first side seam. Winding the tube onto a core for later cutting of the upper surface and the lower surface to form two facing bag streams, each of said bag streams having a first predetermined width. Folding each of said bag streams to approximately one third of said first predetermined width. 
     (10) In still a further variant of the method of making trifold side-seamed plastic produce bags, the method includes the step of rolling each of said bag streams to form a bag roll. 
     (11) In another variant of the method of making trifold side-seamed plastic produce bags, the method includes the step of rolling each of said bag streams about a cylindrical core to form a bag roll. 
     (12) In still another variant of the method, each of said bag streams is folded in a Z-fold configuration. 
     (13) In yet another variant of the method, each of said bag streams is folded in a C-fold configuration. 
     (14) An apparatus for making tri-fold side-seamed plastic produce bags includes the following components. A supply of thermoplastic resin is provided. An extruder is provided. The extruder is capable of extruding a continuous tube of thermoplastic film. A tubing flattener is provided. The flattener is capable of flattening the tube. The tube has an upper surface, a lower surface, first and second side edges. A  perforator  is provided. The  perforator  is capable of forming a perforation perpendicular to the first and second side edges across an entire width of the tube. A sealer is provided. The sealer is capable of sealing the tube at a first side seam spaced from and parallel to the perforation and at a second side seam spaced from and parallel to the first side seam. A slitter is provided. The slitter is capable of cutting the upper surface and the lower surface to form two facing bag streams. Each of the bag streams has a first predetermined width. A folder is provided. The folder is capable of folding each of the bag streams to approximately one third of the first predetermined width. 
     (15) In another variant of the apparatus, a corona treater is provided. The corona treater is capable of corona treating at least one upper and lower surface of the tube prior to folding. 
     (16) In still another variant, a printer is provided. The printer capable of printing advertising or informational material on at least one of the corona treated surfaces of the flattened tube. 
     (17) In yet another variant, a bag rolling device is provided. The bag rolling device is capable of rolling each of the bag streams to form a bag roll. 
     (18) In a further variant, a supply of cores is provided. Each of the bag streams is wound around one of the cores to form the bag rolls. 
     (19) In still a further variant, the folder is capable of folding each of the bag streams in a Z-fold configuration. 
     (20) In yet a further variant, the folder is capable of folding each of the bag streams in a C-fold configuration. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the preferred embodiment of the invention, a trifold side seamed produce bag as formed in  FIG. 1A ; 
         FIG. 1A  is a perspective view of the  FIG. 1  embodiment of the invention as the bags are formed, illustrating two facing streams of side seamed plastic produce bags attached with perforations; 
         FIG. 1B  is a perspective view of the  FIG. 1  embodiment after folding in thirds; 
         FIG. 2  is a perspective view of a first method of making the invention illustrating the flattening and slitting of the tube, perforating the tube, sealing the bag side edges, cutting the two facing bag streams apart, folding them in thirds and winding them on rolls; 
         FIG. 3  is a perspective view of the  FIG. 2  embodiment further illustrating corona treatment and printing of the tube prior to slitting; 
         FIG. 4  is a perspective view of a coreless roll of the  FIG. 1  bags; 
         FIG. 5  is a perspective view of a cored roll of the  FIG. 1  bags; 
         FIG. 6  is a perspective view of the  FIG. 1  bag folded into a Z-fold configuration; 
         FIG. 7  is a perspective view of the  FIG. 1  bag folded into a C-fold configuration; 
         FIG. 8  is a perspective view of a process for forming a flattened plastic tube and rolling same onto a core for later processing; 
         FIG. 9  is a perspective view of a second portion of the  FIG. 8  process in which the printed tube is slit, perforated, sealed and cut into two facing bag streams; 
         FIG. 10  is a perspective view of another method of making the  FIG. 1  bags by corona treating, slitting, printing, perforating and sealing the tube and winding the tube onto a core for later separation into two facing bag streams; 
         FIG. 11  is a perspective view of a second portion of the  FIG. 10  process in which the printed tube, slit, perforated and sealed tube is cut into two facing bag streams; 
         FIG. 12  is a perspective view of still another method of making the  FIG. 1  bags by corona treating, printing, slitting, perforating and sealing the tube and winding the tube onto a core for later separation into two facing bag streams; 
         FIG. 13  is a perspective view of a second portion of the  FIG. 12  process in which the printed tube, slit, perforated and sealed tube is cut into two facing bag streams; 
         FIG. 14  is a detailed perspective view of a plastic film slitting mechanism removing a central strip from the tube; 
         FIG. 15  is a detailed perspective view of a bag folding mechanism capable of folding a bag stream into thirds; 
         FIG. 16  is a detailed perspective view of the bag folding mechanism operating on a stream of trifold side seamed bags; 
         FIG. 17  is a perspective view of the preferred embodiment of the invention, a trifold side seamed produce bag as formed in  FIG. 17A ; 
         FIG. 17A  is a perspective view of the  FIG. 17  embodiment of the invention as the bags are formed, illustrating two facing streams of side seamed plastic produce bags attached with perforations; 
         FIG. 17B  is a perspective view of the  FIG. 17  embodiment after folding in thirds; 
         FIG. 18  is a perspective view of a first method of making the invention illustrating the flattening and slitting of the tube, perforating the tube, sealing the bag side edges, cutting the two facing bag streams apart, folding them in thirds and winding them on rolls; 
         FIG. 19  is a perspective view of the  FIG. 18  embodiment further illustrating corona treatment and printing of the tube prior to slitting; 
         FIG. 20  is a perspective view of a coreless roll of the  FIG. 17  bags; 
         FIG. 21  is a perspective view of a cored roll of the  FIG. 17  bags; 
         FIG. 22  is a perspective view of the  FIG. 17  bag folded into a Z-fold configuration; 
         FIG. 23  is a perspective view of the  FIG. 17  bag folded into a C-fold configuration; 
         FIG. 24  is a perspective view of another method of making the  FIG. 1  bags by corona treating, printing, perforating and sealing the tube and winding the tube onto a core for later separation into two facing bag streams; 
         FIG. 25  is a perspective view of a second portion of the  FIG. 24  process in which the printed tube, perforated and sealed tube is cut into two facing bag streams; 
         FIG. 26  is a detailed perspective view of a bag folding mechanism capable of folding a bag stream into thirds; and 
         FIG. 27  is a detailed perspective view of the bag folding mechanism operating on a stream of trifold side seamed bags. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     (1)  FIGS. 1, 1A and 1B  illustrate a trifold side-seamed plastic produce bag  10  providing the desired features that may be constructed from the following components. A front wall  15  is provided. The front wall  15  has a top edge  20 , a bottom edge  25 , a first side edge  30 , a second side edge  35  and a first predetermined height  40 . A back wall  45  is provided. The back wall  45  has an upper edge  50 , a lower edge  55 , a first side edge  60 , a second side edge  65  and a second predetermined height  70  greater than the first predetermined height  40 . The front wall  15  and the back wall  45  are formed from a single piece of plastic film  75  such that the bottom edge  25  of the front wall  15  is joined seamlessly with the lower edge  55  of the back wall  45 . 
     The first side edge  30  of the front wall  15  is attached to the first side edge  60  of the back wall  45  at a first side seam  80 . The second side edge  35  of the front wall  15  is attached to the second side edge  65  of the back wall  45  at a second side seam  85 . A perforation  90  is provided. The perforation  95  is spaced from the second side seam  85  and extends from the upper edge  50  of the back wall  45  to the lower edge  55  of the back wall  45 . The perforation  90  joins the bag  10  to a subsequent bag  10   a . First  17  and second  19  fold lines are provided. The first  17  and second  19  fold lines are parallel to the upper  50  and lower  55  edges and spaced from the upper  50  and lower  55  edges, respectively, by approximately one third of the second predetermined height  70 . As illustrated in  FIG. 1A , when separated from the subsequent bag  10   a , the bag  10  will have a back wall  45  of greater height than the front wall  15 , thereby providing a means for locating an opening  100  of the bag  10 . 
     (2) A method of making trifold side-seamed plastic produce bags  10 , as illustrated in  FIGS. 2 and 3 , comprises the steps of: extruding a continuous tube  105  of thermoplastic film  75  and flattening the tube  105 . The tube  105  has an upper surface  110 , a lower surface  115 , first  120  and second  125  side edges. Slitting the upper surface  110  to remove a strip of plastic material  130  to form a cut  135 . The cut  135  has a first side  140  and a second side  145 . The first  140  and second  145  sides are parallel to the first  120  and second  125  side edges of the tube  105 . Removing the strip  130 . Forming a perforation  90  perpendicular to the first  120  and second  125  side edges across an entire width  150  of the tube  105 . Sealing the tube  105  at a first side seam  80 . The first side seam  80  is spaced from and parallel to the perforation  90 . Sealing the tube  105  at a second side seam  85 . The second side seam  85  is spaced from and parallel to the first side seam  80 . Cutting the lower surface  115  at a point  155  below and between the first  140  and second  145  sides of the slit  135  in the upper surface  110  to form two facing bag streams  160 ,  165 , each of said bag streams  160 ,  165  having a first predetermined width  21 . Folding each of the bag streams  160 ,  165  to approximately one third of the first predetermined width  21 . 
     (3) In a variant of the method of making trifold side-seamed plastic produce bags  10 , as illustrated in  FIG. 4 , the method includes the further step of corona treating  170  at least one of the upper surface  110  and the lower  115  surface of the flattened tube  105  prior to slitting the upper surface  110  to remove the strip of plastic material  130 . 
     (4) In a further variant of the method, also illustrated in  FIG. 3 , the method includes the further step of printing advertising or informational material  175  on at least one of the corona treated  170  surfaces  110 ,  115  of the flattened tube  105 . 
     (5) In still a further variant of the method, as illustrated in  FIGS. 2 and 4 , the method includes the further step of rolling each of the bag streams  160 ,  165  to form a bag roll  180 . 
     (6) In yet a further variant of the method, as illustrated in  FIG. 5 , the method includes the further step of rolling each of the bag streams  160 ,  165  about a cylindrical core  185  to form a bag roll  190 . 
     (7) In another variant of the method, as illustrated in  FIG. 6 , each of the bag streams  160 ,  165  is folded in a Z-fold configuration  23 . 
     (8) In still another variant of the method, as illustrated in  FIG. 7 , each of the bag streams is folded in a C-fold configuration  27 . 
     (9) In another variant of the method of making trifold side-seamed plastic produce bags  10 , as illustrated in  FIGS. 8 and 9 , the method includes the steps of: Extruding a continuous tube  105  of plastic film  75  and flattening the tube  105 . The tube  105  has an upper surface  110 , a lower surface  115 , first  120  and second  125  side edges. Winding the flattened tube  105  onto a core  195 . Moving the core  195  to a cutting machine  200 . The cutting machine  200  includes a slitter  205 . Feeding the tube  105  from the core  195  into the cutting machine  200 . Slitting the upper surface  110  to remove a strip of plastic material  130  and form a cut  135 . The cut  135  has a first side  140  and a second side  145 . The first  140  and second  145  sides are parallel to the first  120  and second  125  side edges of the tube  105 . Removing the strip  130 . Forming a perforation  90  perpendicular to the first  120  and second  125  side edges across an entire width  150  of the tube  105 . Sealing the tube  105  at a first side seam  80 . The first side seam  80  is spaced from and parallel to the perforation  90 . Sealing the tube  105  at a second side seam  85 . The second side seam  85  is spaced from and parallel to the first side seam  80 . Cutting the lower surface  115  at a point  155  below and between the first  140  and second  145  sides of the cut  135  in the upper surface  110  to form two facing bag streams  160 ,  165 , each of said bag streams  160 ,  165  having a first predetermined width  21 . Folding each of the bag streams  160 ,  165  to approximately one third of the first predetermined width  21 . 
     (10) In a further variant of the method of making trifold side-seamed plastic produce bags  10 , also illustrated in  FIG. 7 , the method includes the further step of corona treating  170  at least one of the upper surface  110  and the lower surface  115  of the flattened tube  105  prior to slitting the upper surface  110  to remove the strip of plastic material  130 . 
     (11) In still a further variant of the method, as illustrated in  FIG. 3 , the method includes the further step of printing advertising or informational material  175  on at least one of the corona treated  170  surfaces  110 ,  115  of the flattened tube  105 . 
     (12) In still a further variant of the method, as illustrated in  FIG. 4 , the method includes the further step of rolling each of the bag streams  160 ,  165  to form a bag roll  180 . 
     (13) In yet a further variant of the method, as illustrated in  FIG. 5 , the method includes the further step of rolling each of the bag streams  160 ,  165  about a cylindrical core  185  to form a bag roll  190 . 
     (14) In another variant of the method, as illustrated in  FIG. 6 , each of the bag streams  160 ,  165  is folded in a Z-fold configuration  23 . 
     (15) In still another variant of the method, as illustrated in  FIG. 7 , each of the bag streams is folded in a C-fold configuration  27 . 
     (16) In yet another variant of the method of making trifold side-seamed plastic produce bags  10 , as illustrated in  FIGS. 10 and 11 , the method includes the steps of: Extruding a continuous tube  105  of plastic film  75  and flattening the tube  105 . The tube  105  has an upper surface  110 , a lower surface  115 , first  120  and second  125  side edges. Corona treating  170  at least one of the upper surface  110  and the lower surface  115  of the flattened tube  105 . Slitting the upper surface  110  to remove a strip of plastic material  130  to form a cut  135 . The cut  135  has a first side  140  and a second side  145 . The first  140  and second  145  sides are parallel to the first  120  and second  125  side edges of the tube  105 . Removing the strip  130 . Printing either advertising or informational material  175  on at least one of the corona treated  170  surfaces  110 ,  115  of the flattened tube  105 . Forming a perforation  90  perpendicular to the first  120  and second  125  side edges across an entire width  150  of the tube  105 . Sealing the tube  105  at a first side seam  80  spaced from and parallel to the perforation  90 . Sealing the tube  105  at a second side seam  85 . The second side seam  85  is spaced from and parallel to the first side seam  80 . Cutting the lower surface  115  at a point  155  below and between the first  140  and second  145  sides of the cut  135  in the upper surface  110  to form two facing bag streams  160 ,  165 , each of said bag streams  160 ,  165  having a first predetermined width  21 . Folding each of the bag streams  160 ,  165  to approximately one third of the first predetermined width  21 , as illustrated in  FIG. 2 . 
     (17) In still a further variant of the method, as illustrated in  FIG. 4 , the method includes the further step of rolling each of the bag streams  160 ,  165  to form a bag roll  180 . 
     (18) In yet a further variant of the method, as illustrated in  FIG. 5 , the method includes the further step of rolling each of the bag streams  160 ,  165  about a cylindrical core  185  to form a bag roll  190 . 
     (19) In another variant of the method, as illustrated in  FIG. 6 , each of the bag streams  160 ,  165  is folded in a Z-fold configuration  23 . 
     (20) In still another variant of the method, as illustrated in  FIG. 7 , each of the bag streams is folded in a C-fold configuration  27 . 
     (21) In still another variant of the method of making trifold side-seamed plastic produce bags  10 , as illustrated in  FIGS. 12 and 13 , the method includes the steps of: Extruding a continuous tube  105  of plastic film  75  and flattening the tube  105 . The tube  105  has an upper surface  110 , a lower surface  115 , first  120  and second  125  side edges. Corona treating  170  at least one of the upper surface  110  and the lower surface  115  of the flattened tube  105 . Printing either advertising or informational material  175  on at least one of the corona treated  170  surfaces  110 ,  115  of the flattened tube  105 . Slitting the upper surface  110  to remove a strip of plastic material  130  to form a cut  135 . The cut  135  has a first side  140  and a second side  145 . The first  140  and second  145  sides are parallel to the first  120  and second  125  side edges of the tube  105 . Removing the strip  130 . Forming a perforation  90  perpendicular to the first  120  and second  125  side edges across an entire width  150  of the tube  105 . Sealing the tube  105  at a first side seam  80  spaced from and parallel to the perforation  90 . Sealing the tube  105  at a second side seam  85 . The second side seam  85  is spaced from and parallel to the first side seam  80 . Winding the tube  105  onto a core  185  for later cutting of the lower surface  115  at a point  155  below and between the first  140  and second  145  sides of the cut  135  in the upper surface  110  to form two facing bag streams  160 ,  165 , each of said bag streams  160 ,  165  having a first predetermined width  21 . Folding each of the bag streams  160 ,  165  to approximately one third of the first predetermined width  21 . 
     (22) In a further variant of the method, as illustrated in  FIG. 4 , the method includes the further step of rolling each of the bag streams  160 ,  165  to form a bag roll  180 . 
     (23) In still a further variant of the method, as illustrated in  FIG. 5 , the method includes the further step of rolling each of the bag streams  160 ,  165  about a cylindrical core  185  to form a bag roll  190 . 
     (24) In another variant of the method, as illustrated in  FIG. 6 , each of the bag streams  160 ,  165  is folded in a Z-fold configuration  23 . 
     (25) In still another variant of the method, as illustrated in  FIG. 7 , each of the bag streams is folded in a C-fold configuration  27 . 
     (26) As illustrated in  FIG. 12 , an apparatus  400  for making tri-fold side-seamed plastic produce bags  10  includes the following components. A supply of thermoplastic resin  405  is provided. An extruder  410  is provided. The extruder  410  is capable of extruding a continuous tube  105  of thermoplastic film  75 . A tubing flattener  415  is provided. The flattener  415  is capable of flattening the tube  105 . The tube  105  has an upper surface  110 , a lower surface  115 , first  120  and second  125  side edges. A cutting machine  200  is provided. The cutting machine  200 , as illustrated in  FIGS. 2 and 14 , is capable of slitting the upper surface  110  to remove a strip of plastic material  130  to form a cut  135 . The cut  135  has a first side  140  and a second side  145 . The first  140  and second  145  sides are parallel to the first  120  and second  125  side edges of the tube  105 . A perforator  420  is provided. The perforator  420  is capable of forming a perforation  90  perpendicular to the first  120  and second  125  side edges across an entire width  150  of the tube  105 . A sealer  425  is provided. The sealer  425  is capable of sealing the tube  105  at a first side seam  80  spaced from and parallel to the perforation  90  and at a second side seam  85  spaced from and parallel to the first side seam  80 . A slitter  430  is provided. The is slitter  430  is capable of cutting the lower surface  115  at a point  155  below and between the first  140  and second  145  sides of the cut  135  in the upper surface  110  to form two facing bag streams  160 ,  165 . Each of the bag streams  160 ,  165  has a first predetermined width  21 . A folder  435 , as illustrated in  FIGS. 2, 15 and 16 , is provided. The folder  435  is capable of folding each of the bag streams  160 ,  165  to approximately one third of the first predetermined width  21 . 
     (27) In another variant of the apparatus  400 , as illustrated in  FIG. 3 , a corona treater  440  is provided. The corona treater  440  is capable of corona treating at least one of the upper  110  and lower  115  surface of the tube  105  prior to folding. 
     (28) In still another variant, a printer  445  is provided. The printer  445  is capable of printing advertising or informational material  175  on at least one of the corona treated surfaces  110 ,  115  of the flattened tube  105 . 
     (29) In yet another variant, as illustrated in  FIGS. 2 and 4 , a bag rolling device  450  is provided. The bag rolling device  450  is capable of rolling each of the bag streams  160 ,  165  to form a bag roll  180 . 
     (30) In a further variant, as illustrated in  FIG. 5 , a supply of cores  185  is provided. Each of the bag streams  160 ,  165  is wound around one of the cores  185  to form the bag rolls  190 . 
     (31) In still a further variant, the folder  435  is capable of folding each of the bag streams  160 ,  165  in a Z-fold configuration  23 , as illustrated in  FIG. 6 . 
     (32) In yet a further variant, the folder  435  is capable of folding each of the bag streams  160 ,  165  in a C-fold configuration  27 , as illustrated in  FIG. 7 . 
     (1)  FIGS. 17, 17A and 17B  illustrate a trifold side-seamed plastic produce bag  10  providing the desired features that may be constructed from the following components. A front wall  15  is provided. The front wall  15  has a top edge  20 , a bottom edge  25 , a first side edge  30 , a second side edge  35  and a first predetermined height  40 . A back wall  45  is provided. The back wall  45  has an upper edge  50 , a lower edge  55 , a first side edge  60 , a second side edge  65  and said first predetermined height  40 . The front wall  15  and the back wall  45  are formed from a single piece of plastic film  75  such that the bottom edge  25  of the front wall  15  is joined seamlessly with the lower edge  55  of the back wall  45 . 
     The first side edge  30  of the front wall  15  is attached to the first side edge  60  of the back wall  45  at a first side seam  80 . The second side edge  35  of the front wall  15  is attached to the second side edge  65  of the back wall  45  at a second side seam  85 . A perforation  90  is provided. The perforation  90  is spaced from the second side seam  85  and extends from the upper edge  50  of the back wall  45  to the lower edge  55  of the back wall  45 . The perforation  90  joins the bag  10  to a subsequent bag  10   a . First  17  and second  19  fold lines are provided. The first  17  and second  19  fold lines are parallel to the upper  50  and lower  55  edges and spaced from the upper  50  and lower  55  edges, respectively, by approximately one third of the first predetermined height  40 . As illustrated in  FIG. 17A , when separated from the subsequent bag  10   a , the bag  10  will have a front wall  15  and a back wall  45  of substantially identical height. 
     (2) A method of making trifold side-seamed plastic produce bags  10 , as illustrated in  FIGS. 18 and 19  comprises the steps of: extruding a continuous tube  105  of thermoplastic film  75  and flattening the tube  105 . The tube  105  has an upper surface  110 , a lower surface  115 , first  120  and second  125  side edges. Forming a perforation  90  perpendicular to the first  120  and second  125  side edges across an entire width  150  of the tube  105 . Sealing the tube  105  at a first side seam  80 . The first side seam  80  is spaced from and parallel to the perforation  90 . Sealing the tube  105  at a second side seam  85 . The second side seam  85  is spaced from and parallel to the first side seam  80 . Cutting the upper surface  110  and the lower surface  115  to form two facing bag streams  160 ,  165 , each of said bag streams  160 ,  165  having a first predetermined width  21 . Folding each of the bag streams  160 ,  165  to approximately one third of the first predetermined width  21 . 
     (3) In a variant of the method of making trifold side-seamed plastic produce bags  10 , as illustrated in  FIG. 19 , the method includes the further step of corona treating  170  at least one of the upper surface  110  and the lower  115  surface of the flattened tube  105 . 
     (4) In a further variant of the method, also illustrated in  FIG. 19 , the method includes the further step of printing advertising or informational material  175  on at least one of the corona treated  170  surfaces  110 ,  115  of the flattened tube  105 . 
     (5) In still a further variant of the method, as illustrated in  FIGS. 18 and 20 , the method includes the further step of rolling each of the bag streams  160 ,  165  to form a bag roll  180 . 
     (6) In yet a further variant of the method, as illustrated in  FIG. 21 , the method includes the further step of rolling each of the bag streams  160 ,  165  about a cylindrical core  185  to form a bag roll  190 . 
     (7) In another variant of the method, as illustrated in  FIG. 22 , each of the bag streams  160 ,  165  is folded in a Z-fold configuration  23 . 
     (8) In still another variant of the method, as illustrated in  FIG. 23 , each of the bag streams is folded in a C-fold configuration  27 . 
     (9) In yet another variant of the method of making trifold side-seamed plastic produce bags  10 , as illustrated in  FIGS. 24 and 25 , the method includes the steps of: Extruding a continuous tube  105  of plastic film  75  and flattening the tube  105 . The tube  105  has an upper surface  110 , a lower surface  115 , first  120  and second  125  side edges. Corona treating  170  at least one of the upper surface  110  and the lower surface  115  of the flattened tube  105 . Printing either advertising or informational material  175  on at least one of the corona treated  170  surfaces  110 ,  115  of the flattened tube  105 . Forming a perforation  90  perpendicular to the first  120  and second  125  side edges across an entire width  150  of the tube  105 . Sealing the tube  105  at a first side seam  80  spaced from and parallel to the perforation  90 . Sealing the tube  105  at a second side seam  85 . The second side seam  85  is spaced from and parallel to the first side seam  80 . Winding the tube  105  onto a core  185  for later cutting of the upper surface  110  and the lower surface  115  to form two facing bag streams  160 ,  165 , each of said bag streams  160 ,  165  having a first predetermined width  21 . Folding each of the bag streams  160 ,  165  to approximately one third of the first predetermined width  21 , as illustrated in  FIG. 18 . 
     (10) In still a further variant of the method, as illustrated in  FIG. 20 , the method includes the further step of rolling each of the bag streams  160 ,  165  to form a bag roll  180 . 
     (11) In yet a further variant of the method, as illustrated in  FIG. 21 , the method includes the further step of rolling each of the bag streams  160 ,  165  about a cylindrical core  185  to form a bag roll  190 . 
     (12) In another variant of the method, as illustrated in  FIG. 22 , each of the bag streams  160 ,  165  is folded in a Z-fold configuration  23 . 
     (13) In still another variant of the method, as illustrated in  FIG. 23 , each of the bag streams is folded in a C-fold configuration  27 . 
     (14) As illustrated in  FIG. 18 , an apparatus  400  for making tri-fold side-seamed plastic produce bags  10  includes the following components. A supply of thermoplastic resin  405  is provided. An extruder  410  is provided. The extruder  410  is capable of extruding a continuous tube  105  of thermoplastic film  75 . A tubing flattener  415  is provided. The flattener  415  is capable of flattening the tube  105 . The tube  105  has an upper surface  110 , a lower surface  115 , first  120  and second  125  side edges. A perforator  420  is provided. The perforator  420  is capable of forming a perforation  90  perpendicular to the first  120  and second  125  side edges across an entire width  150  of the tube  105 . A sealer  425  is provided. The sealer  425  is capable of sealing the tube  105  at a first side seam  80  spaced from and parallel to the perforation  90  and at a second side seam  85  spaced from and parallel to the first side seam  80 . A slitter  430  is provided. The is slitter  430  is capable of cutting the upper surface  110  and the lower surface  115  to form two facing bag streams  160 ,  165 . Each of the bag streams  160 ,  165  has a first predetermined width  21 . A folder  435 , as illustrated in  FIGS. 18, 26 and 27 , is provided. The folder  435  is capable of folding each of the bag streams  160 ,  165  to approximately one third of the first predetermined width  21 . 
     (15) In another variant of the apparatus  400 , as illustrated in  FIG. 19 , a corona treater  440  is provided. The corona treater  440  is capable of corona treating at least one of the upper  110  and lower  115  surface of the tube  105  prior to folding. 
     (16) In still another variant, a printer  445  is provided. The printer  445  is capable of printing advertising or informational material  175  on at least one of the corona treated surfaces  110 ,  115  of the flattened tube  105 . 
     (17) In yet another variant, as illustrated in  FIGS. 18 and 20 , a bag rolling device  450  is provided. The bag rolling device  450  is capable of rolling each of the bag streams  160 ,  165  to form a bag roll  180 . 
     (18) In a further variant, as illustrated in  FIG. 21 , a supply of cores  185  is provided. Each of the bag streams  160 ,  165  is wound around one of the cores  185  to form the bag rolls  190 . 
     (19) In still a further variant, the folder  435  is capable of folding each of the bag streams  160 ,  165  in a Z-fold configuration  23 , as illustrated in  FIG. 22 . 
     (20) In yet a further variant, the folder  435  is capable of folding each of the bag streams  160 ,  165  in a C-fold configuration  27 , as illustrated in  FIG. 23 . 
     The Tri-fold side seamed produce bag  10  and methods and apparatus for making same have been described with reference to particular embodiments. Other modifications and enhancements can be made without departing from the spirit and scope of the claims that follow.

Technology Category: 7