Abstract:
A method and apparatus for continuously or intermittently and vertically forming, filling and sealing packaging includes an infeed section, a pleating assembly, a forming tube and a sealing assembly. The pleating assembly imparts at least one pleat to the film. The forming tube receives the film from the infeed section after the pleat has been made. A film tube is formed about the forming tube. The film tube is vertically fed downward to the sealing assembly which imparts seals to the film tube, thereby forming packages. A hole punch punches holes in the film tube. The film travels a film path that includes the hole punch, the forming tube, the vertical seal assembly and the horizontal seal assembly.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates generally to the art of vertical pouch machines. More specifically, it relates to vertical form fill seal machines, wherein pouches are formed from a continuously or intermittently moving film.  
       BACKGROUND OF THE INVENTION  
       [0002]     Vertical form fill and seal continuous and intermittent pouch machines are known in the art. Generally, they receive a continuous film and form the film into a film tube (i.e., the film is formed and sealed to have a closed cross section) about a forming tube. The forming tube typically has a circular or oval cross section, although other cross sections have been used. The film is continuously or intermittently fed around the forming tube and sealed vertically to form the film tube. The vertical seal is typically a lap seal or a fin seal.  
         [0003]     Forming tubes can include ploughs or tucker bars to form pleats or creases that can be used to form gussets, to make stand-up pouches. The plough or tucker bar applies tension in an inward direction creasing the film tube. Forming plates may be provided on either side of the plough, applying tension in an outward direction. Two ploughs centered about a single tucker bar will form a “W” shaped gusset. The ploughs and tucker bars may be fixed in one location, such as at the bottom of the forming tube, or moveable in any direction. Examples of a tucker bar and forming plates may be seen in U.S. Pat. No. 6,679,034, hereby incorporated by reference. Tucker bars (and forming plates) may be used on a single side of the pouch, forming one gusset, or on opposing sides, forming two gussets. Forming tube assemblies may be changed out to form bags of other sizes. Another prior art machine is shown in U.S. Pat. No. 6,691,491, hereby incorporated by reference.  
         [0004]     After the film tube passes the forming tube and tucker bar(s) it moves vertically downward to a sealing zone. Seal bars intermittently create a horizontal seal. The seal bars may be rotary, and can be in pairs to increase machine speed. An example of seal bars is given in U.S. Pat. No. 6,519,922, hereby incorporated by reference.  
         [0005]     The horizontal seal forms the top seal of the pouch below the seal, and the bottom of the pouch above the seal. After the seal is formed a scale or other input device drops a predetermined amount of product through the forming tube. At the same time the film tube is advancing downward. When the subsequent seal is formed the product is below the sealing zone. The seal is formed, forming the top seal of the filled pouch and the bottom seal of the pouch above, thus sealing the product into the pouch. Stripper bars, such as those shown in U.S. Pat. No. 6,519,922 may be used to help ensure the product is below the sealing zone when the seal is made.  
         [0006]     Different types of pouches may be formed with vertical form filling seal continuous packaging machines, such as pillow bags, stand up pouches, other pouches, etc. Standup pouches are typically formed with a gusset at (what will be) the bottom of the pouch using ploughs and a tucker bar as described above. For example, a pouch made on a vertical pouch machine may have a gusset put on one vertical edge of the pouch. However, when the pouches are separated from one another they are rotated 90 degrees so that what had been the vertical edge (with the gusset) of a pouch becomes the bottom edge of the pouch. The standup pouches look and perform well when one seal is placed at the bottom of each of the outer folds of the gusset. (The gusset is usually formed to be a “W” with the outer folds being the folds the pouch stands on.) However, prior art machines have not been able to reliably place a seal and typically tried to create the seal as the gusset is being formed. It is difficult with such an arrangement to change features of the pleat, such as depth or location, the entire forming assembly was changed out. Accordingly, a vertical form fill and seal pouch machine that provides a gusset with a pleat and seal on the outer folds of the gusset is desirable. Also, such a pleat should be easily adjustable.  
         [0007]     When forming a seal on the bottom of the gusset, a pleat may be formed to locate the seal. However, the film can be difficult to crease without damaging the film. Accordingly, a vertical form fill and seal pouch machine that provides for pleating the film without damaging it is desirable.  
         [0008]     Stand up pouches are typically formed such that the two sides of the gusset are equal in length. This results in a bag that stands upright. However, other gusset designs may be useful, such as one where the backside of the gusset is shorter than the front side, so that the pouch tilts away from the consumer or on the shelf. It is desirable to be able to control the depth and location of pleats and seals used to form a gusset, so that the gusset is thereby adjustable. Accordingly, a vertical, form fill and seal pouch machine that provides for adjustable seals and pleats on the gusset is desirable.  
         [0009]     Standup pouches and are sometimes displayed to the consumer by hanging them from a rod through a hanger hole punched in the top of the pouch. Holes have been punched in pouches using horizontal machines and using intermittent vertical machines. It is desirable to provide a hole punches in continuous vertical machines, but thus far a hole punch that may be operated fast enough and with sufficient accuracy has not been available. Accordingly, in continuous vertical form fill and seal machine that provides a hole punch in what will be the top of a pouch is desirable.  
       SUMMARY OF THE PRESENT INVENTION  
       [0010]     According to a first aspect of the invention a vertical, form, fill and seal packaging machine includes an infeed section, a pleating assembly, a forming tube and a sealing assembly. The pleating assembly imparts at least one pleat to the film. The forming tube receives the film from the infeed section after the pleat has been made. A film tube is continuously formed about the forming tube. The film tube is vertically fed downward to the sealing assembly which imparts seals to the film tube, thereby forming packages.  
         [0011]     According to a second aspect of the invention a continuous, vertical, form, fill and seal packaging machine includes a forming tube that receives film from an infeed section, and about which a film tube is continuously formed. The film is vertically fed downward past a vertical seal assembly to impart vertical seals to form the film tube. A horizontal seal assembly makes horizontal seals on the formed film tube. A hole punch punches holes in the film tube. The film travels a film path that includes the hole punch, the forming tube, the vertical seal assembly and the horizontal seal assembly.  
         [0012]     According to a third aspect of the invention a method of vertically forming, and sealing packages includes feeding film and imparting at least one pleat to the film. The pleated film is provided to a forming tube and vertical seals are made on the film, thereby forming a film tube. A series of horizontal seals are made to form packages.  
         [0013]     According to a fourth aspect of the invention a method of continuously, vertically, forming, and sealing packages, includes feeding film to a forming tube and imparting a vertical seal to the film, thereby forming a film tube. A hole is punched intermittently in the film after the film reaches the forming tube and a series of horizontal seals are applied to the film, thereby forming packages.  
         [0014]     A pleat sealing assembly is disposed to receive the film after it passes through the pleating assembly and it seals the at least one pleat in another embodiment. The pleat is sealed prior to the film being received by the forming tube in various embodiments.  
         [0015]     The pleating assembly and/or the pleat sealing assembly are in the infeed section in other embodiments.  
         [0016]     The pleating assembly includes at least two pleaters to form at least two pleats in other embodiments.  
         [0017]     Each pleater may include an adjustable shoe and a fixed plate in various embodiments.  
         [0018]     User controls for pleat depth adjustment, and/or cross-machine pleat location, and\or pleat separation are provided and operatively connected to the pleating assembly in various embodiments.  
         [0019]     The forming is intermittent in some embodiments and continuous in other embodiments.  
         [0020]     The hole punch creates a hanging chad that may have an attached portion of the chad on a leading edge of the hole in other embodiments.  
         [0021]     The hole punch is located on the film path after the forming tube and vertical seal assembly, but before the horizontal seal assembly in one embodiment.  
         [0022]     Product is intermittently provided through the forming tube, to fill each package between the horizontal seals.  
         [0023]     Other principal features and advantages of the invention will become apparent to those skilled in the art upon review of the following drawings, the detailed description and the appended claims.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]      FIG. 1  is a side view of a continuous, vertical form, fill and seal packaging machine in accordance with the preferred embodiment;  
         [0025]      FIG. 2  is a side view of a sealing/pleating assembly of  FIG. 1 ; and  
         [0026]      FIG. 3  is a view of a pleater of  FIG. 2 , taken along section A-A. 
     
    
       [0027]     Before explaining at least one embodiment of the invention in detail it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting. Like reference numerals are used to indicate like components.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0028]     While the present invention will be illustrated with reference to a particular vertical form fill and seal machine used in a particular way, it should be understood at the outset that the invention can also be implemented with other machines used in other ways.  
         [0029]     Generally, the preferred embodiment of the invention provides for a continuous, vertical form, fill and seal packaging machine that pleats the film, and seals the pleat, prior to the film reaching a forming tube. Also, a hole punch is provided after the film has been formed into a tube, to provide a hanger hole for the film. The invention may be implemented using known prior art technology for the remainder of the machine. For example, the preferred embodiment is similar to a CMD Corp CM300 continuous, vertical form, fill and seal packaging machine, but with the changes described generally above. Alternative embodiments include an intermittent vertical, form, fill and seal packaging machine.  
         [0030]     The pleats are formed or imparted to the film and sealed in a pleat assembly in the preferred embodiment. The pleat assembly is located in the infeed section (the section from the roll of film to the forming tube), and the film is provided to the pleat assembly from the unwind roll. The pleat assembly forms two pleats in the preferred embodiment. Each pleat is formed by the action of a moveable shoe, and an angled fixed (or dead) plate (collectively called a pleater). Pleater, as used herein, includes the components acting together to form a pleat. The film is pulled along the dead plate until reaching the shoe. The amount of film pulled is half of the depth of the pleat. The film is driven by rolls at the center (cross-direction) of the film, so that the edges of the film are free to be drawn inward as the pleat is formed.  
         [0031]     The pleat is easily adjusted by the user without reconfiguring the machine. The pleat depth is adjusted by adjusting the position of the shoe relative to the angled dead plate, the distance between the pleats is adjusted by adjusting the distance between pairs of shoes and dead plates. The cross machine location of the pleats is adjusted by adjusting the cross machine location of both pleaters. The adjustments are made by turning knobs connected via gears to mounting plates for the shoes and dead plates.  
         [0032]     The film travels from the pleat assembly to a sealing zone, where radiant heat is used to heat the film and impart a seal. The radiant heat seals the film, which is preferably a PET film having a 48 gauge thickness (100 gauge=1 mil=0.001 inch), with a co-extruded sealant layer 2-3 mils thick (for example, an LLDPE, HDPE, or ME or combinations thereof for the sealant layer). Other films and film thicknesses may be used. A backing plate is provided to help create a “heat chamber” through which the pleated film passes.  
         [0033]     The preferred embodiment further provides for a hole punch assembly to be mounted between the forming tube and the horizontal seal bars (it is mounted in other locations in other embodiments). The hole punch is preferably synchronized to the horizontal seal bars to form a single hole per pouch. The hole punch must be fast enough to punch the hole at speed the machine will run, and is a D30 punch unit from MAL Ltd., in the preferred embodiment. The hole punch creates a hanging chad (to avoid the mess of punched chads) and leaves the leading 25% of the chad attached, so the chad is pressed back into the hole from which it was formed as the pouch moves downstream. Alternative embodiments provide for different shaped holes, multiple holes, removed chads, or chads attached differently.  
         [0034]     Referring now to  FIG. 1 a  continuous, vertical form, fill and seal packaging machine  100  in accordance with the preferred embodiment is shown. It operates generally as the prior art CMD Corp. CM 300® operates, with the changes described below. The preferred embodiment includes a machine that makes only pouches, but it could be implemented on a machine with rotatable, a quick change unit, or a traditional change unit, to also make pillow bags or other style packages. Also, the preferred embodiment includes a continuous machine, but alternatives include intermittent machines. Before describing the differences between the preferred embodiment and the prior art, the common features will be briefly described.  
         [0035]     Generally, the film is unwound from a roll by infeed section  102 , passes through a dancer assembly  103 , a gusset hole punch  105 , and provided to a forming tube  104 . A vertical seal assembly  106  creates a continuous vertical seal. Forming tube  104  includes a tucker bar and plough assembly that form a gusset in accordance with the prior art. After the gusset is formed a horizontal seal is created with horizontal seal assembly  108 . A scale assembly  110  drops a measured amount of product through the forming tube, filling the pouch, after each horizontal seal is made. It may also have other known features such as notching assembly  109  for notching a zipper.  
         [0036]     Continuous, vertical form, fill and seal packaging machine  100  includes, unlike the prior art, a pleating/sealing assembly  111 , which includes a pleat assembly  120  ( FIG. 2 ), a pleat sealer  122  ( FIG. 2 ) and a hole punch assembly  124 . A single machine controller controls the new and old operations to accurately synchronize the entire process. The operation of is generally described above, and will be described in more detail below. A film  201  is shown having a path from a film roll  115 , to dancer assembly  103 , to gusset hole punch  105 , to pleating/sealing assembly  111 , to forming tube  104 , past vertical seal assembly  106 , to hole punch assembly  124  and then to horizontal seal assembly  108 . A zipper notch assembly  109  is also shown.  
         [0037]     Referring now to  FIG. 2 , a side view of pleat/seal assembly  111 , including assembly  120  and pleat sealer  122 , is shown. A film  201  moves through these assemblies in a generally upward direction, as shown by arrow  203 . Film  201  passes through pleat assembly  120  and is driven by rolls in the center of film  201  to allow the film edges to be drawn in by a pleater  301 .  
         [0038]     Pleater  301  is shown in  FIG. 3 , along with a pleater  303 .  FIG. 3  is a view taken along lines A-A of  FIG. 2 . Pleater  301  includes a moveable shoe  304 , a fixed plate  305  and a mounting plate  306 . Moveable shoe  304  is generally rectangular, and fixed plate  305  is angled along an edge  316  where the pleat is formed. The film moves in the direction of arrow  310 , and the pleat is formed by drawing the film inward from where an edge  315  of dead plate  305  crosses angled edge  316  of shoe  304 . The film is drawn in and pleated until the upper edge of shoe  304  is reached. Thus, the depth of the pleat is a distance  318 , from edge  316  to the center most (center in the cross machine direction) part of edge  315 . Moving shoe  304  towards the center decreases the pleat depth and moving shoe  304  away from the center increases the pleat depth. Shoe  304  is connected to a user-adjustable knob at the side of continuous, vertical form, fill and seal packaging machine  100  to allow the user to easily adjust the depth of the pleat.  
         [0039]     Pleater  303  has a mirror image design, and operates in a similar manner. The two pleats can be adjusted to have different depths by unequally adjusting shoes  304  and  307 .  
         [0040]     Pleaters  301  and  303  are mounted on plates that may be moved in the cross machine direction to adjust the position of the pleats relative to one another. Using two adjustments, one for the distance between them, and the other for left to right adjustment, they can be adjusted to virtually any cross machine direction. These adjustments can be made easily by turning a few knobs, and without changing the machine setup or swapping parts in and out.  
         [0041]     The preferred embodiment provides for a pleat depth (i.e., the distance the pleat extends from the flat surface) of between ⅛ to ¼ inch, and other distances are provided in alternative embodiments. The preferred embodiment further provides for an adjusted distance between pleats of 1 inch to 4.25 inches, centered about the midline of the film. Other adjusted distances may be provided. For example, if the pleats are slightly off center, the pouch will tip on display, for shingling or viewing.  
         [0042]     Referring again to  FIG. 2 , after the pleat is formed a tension roll  205  is provided which helps prevent the pleats from opening. Film  201  then travels to pleat sealing assembly  122 . Pleat sealing assembly  122  includes a radiant heater  307  (which is two vertical heat bars, each aligned with a pleat, in the preferred embodiment), and a backing plate  309 . Backing plate  309  helps form a heat chamber to hold heat in so that the seal is properly made. Preferably, backing plate  309  is disposed to just touch film  201 , and is Teflon® coated to avoid sticking. The preferred film has adhesive on only one side (the sides that touch when the pleat is formed). When the process is stopped, heater  307  can be tilted back to avoid applying heat to the stopped film. Also, in the preferred embodiment, the heat is applied in a low or no tension area, to reduce the likelihood o sticking. Alternative embodiments include running the film on a cushion of air to reduce friction (in the sealing or pleating areas), and/or using other devices to make the seal, such as ultrasonic or infrared heaters.  
         [0043]     After the pleats are sealed, pleated film  210  passes over a large diameter roll  313  that cools the heated film. Roll  313  is passively cooled, although it could be actively cooled. The large diameter also provides tension to help hold the pleats in place. Following large diameter roll  313 , the film can be turned by small diameter roll, because the pleat seals have been set.  
         [0044]     One advantage of forming the pleats prior to forming the film tube is that the gusseting is a much easier and more natural process with pleated film, compared to flat film. Another advantage is the system could intermittently apply pleats, if so desired. If a pleat is large enough, the web is narrower at the forming tube, thus the machine can be designed with this in mind. For example, for two pleats, each 0.25 inches deep, the web will be 1 inch narrower after the pleats are formed.  
         [0045]     The film is then provided to forming tube  104 . Preferably the forming collar is gently sloped, to accommodate the pleats. The preferred forming tube has a cut away section is toward the bottom of the forming tube with ploughs aligned with the pleats to form the gusset. As stated above, a pleated film makes forming a gusset less difficult because it helps locate the film in the proper position. Preferably, the pleats stabilizes the process so that it is more readily repeatable, and reduces the need for fine tuning the machine when setting it up. The preferred embodiment runs at about a hundred bags a minute, although greater or lessor throughputs are contemplated, as is intermittent operation.  
         [0046]     The film is pulled over the forming collar and down the forming tube by pull belts. The multi-layer film (from the pleats) requires greater tension to pull than a single layer film, so the vertical pull belt is provided with larger holes and vacuum pockets to help grip the film. Preferably the holes are 5/32 inches in diameter, and the vacuum pockets are ¼ inch wide, 1 inch long, and ⅛ inch deep, and set at a 45 degree angle relative to the machine direction. A gear box with a 5:1 ratio provides the increased torque needed to pull the film over the collar and maintain the desired registration.  
         [0047]     An alternative embodiment entails using a collar having a cut-out where the pleats are. This reduces the tension needed to pull the film but reduces the adjustability, since the pleats must line up with the cut-outs.  
         [0048]     Hole punch assembly  124  is disposed below forming tube  104  and above the horizontal seal assembly  108 , and located to punch a generally circular hole in the vertical seal (the opposite end of the pouch from the gusset). The punch preferably leaves a hanging chad, roughly attached along the leading quarter-edge, so that chads do not create a mess, and the chad lays flat after being created. The punch is synchronized with horizontal seal assembly  106  so that one hole per pouch is made, and it is located midway along the top (after the pouch is rotated so the vertical seal is at the top). Alternatives include removing the chad, punching multiple holes, leaving the chad attached in different locations, and holes that have other shapes.  
         [0049]     Numerous modifications may be made to the present invention which still fall within the intended scope hereof. Thus, it should be apparent that there has been provided in accordance with the present invention a method and apparatus for continuous, vertical form, fill and seal packaging that fully satisfies the objectives and advantages set forth above. Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.