Abstract:
The invention provides a method of making a bag from a foldable pattern, comprising: a) inserting the foldable pattern into an assembly machine; b) placing a series of glue spots on designated surfaces of the pattern; c) folding the foldable pattern, in a sequence such that the resulting product is a finished bag with a glued bottom; and d) exiting the finished bag from the assembly machine.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to the field of assembling bags made of paper and similar materials. In particular, it relates to a new method of assembling bags from foldable patterns via a machine-driven process.  
       BACKGROUND OF THE INVENTION  
       [0002]     In recent years, as consumer awareness of environmentalism has increased, the use of paper bags has increased significantly, particularly for use as shopping bags (replacing plastic) or as “gift bags” (replacing wrapping paper). The bags are readily re-usable, being generally more durable than plastic, and recyclable. Furthermore, the exterior of the bag can be readily imprinted with a design, either decorative (for a gift bag) or with a company name or logo (for shopping bags).  
         [0003]     Paper bags, in particular those used as shopping bags and gift bags, use glued bottoms to increase the amount of weight that can be supported. The typical fold pattern used has proven difficult to automate and to date has been limited at best to lightweight paper stock and small size products, such as sugar bags and similar items. Gift and shopping bags require more elaborate patterns and are not well-suited to mass production. Therefore, the majority of paper bags used as gift or shopping bags are made by hand labor to create a bag from heavy paper stock and sufficient size and strength to hold heavier products.  
         [0004]     There is clearly a need for a method of assembling paper bags without the need to incorporate hand labor into the assembly process. Furthermore, any such process should be capable of producing a bag of size and strength comparable to the existing bags produced via hand labor.  
       SUMMARY OF THE INVENTION  
       [0005]     According to an aspect of the invention, there is provided a method of making a bag from a foldable pattern, comprising: a) inserting the foldable pattern into an assembly machine; b) placing a series of glue spots on designated surfaces of the pattern; c) folding the foldable pattern, in a sequence such that the resulting product is a finished bag with a glued bottom; and d) exiting the finished bag from the assembly machine. Preferably, an additional step is included of inserting a reinforcing element into the pattern in a position such that the reinforcing element acts to reinforce the bottom of the bag;  
         [0006]     Preferably, the folding step may include folding over a perimeter edge of the pattern to produce a reinforced top for the bag. Optionally, this reinforced top provides an opening to insert a handle.  
         [0007]     Also preferably, the handle is made of string, and is inserted as part of the folding step.  
         [0008]     Other and further advantages and features of the invention will be apparent to those skilled in the art from the following detailed description thereof, taken in conjunction with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which like numbers refer to like elements, wherein:  
         [0010]      FIG. 1  is a top view of a foldable bag pattern for use in the present invention;  
         [0011]      FIG. 2  is a close-up view of the first three steps of the folding process;  
         [0012]      FIG. 3  is a close-up view of the side z-fold step of the folding process;  
         [0013]      FIG. 4  is a side view of the second side z-fold step of the folding process;  
         [0014]      FIG. 5  is a top view of the bag at the midway point of the folding process;  
         [0015]      FIG. 6  is a top view of the bag during the reinforcing piece insertion step of the folding process;  
         [0016]      FIG. 7  is a top view of the bag during the side tab folding step;  
         [0017]      FIG. 8  is a top view of the bag during the first bottom folding step; and  
         [0018]      FIG. 9  is a top view of the bag during the final bottom folding step. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]     Referring to  FIG. 1 , a foldable pattern for a paper bag is indicated by reference numeral  10 . Crease lines for folding the pattern into a bag are shown as dashed lines in  FIG. 1  and all other Figures. Located at the various foldover locations for assembly of the bag are glue spots as exemplified by  200 ,  202  and  204 . Almost any type of glue that securely bonds the bag material to itself is suitable, however, it is preferable that a hot melt glue or an equivalent is used. Additional glue spots are shown in other Figures. While the glue spots shown are only on a single surface where two pieces of the pattern  10  are joined, the spots may be applied to both surfaces that are meant to contact each other, depending on the type of glue used. Also, the total number of glue spots may be adjusted to reflect the dimensions and materials used for the container. Similarly, the size and shape of glue spots can be varied to determine the optimal values for a container of a specific size and material.  
         [0020]     When the pattern  10  is folded into a bag, the glue spots secure the surfaces of the pattern  10  together, at all the seams and the bottom. The result is that the finished bag has a glued bottom and seams, providing structural strength. This strength can be increased by inserting a piece of heavyweight paper or cardboard as a reinforcing element into the bottom as part of the folding and gluing process.  
         [0021]     Another method of reinforcing the bag is along the top. By folding over the perimeter edges  20 ,  22 ,  24  of the pattern and gluing them to each other, a thicker, stronger top edge is created for the finished bag. Preferably, this top edge should include holes ( 26  in  FIG. 1 ) that permit a handle to be inserted. Such handles are often made of string, and can be inserted and glued to the bag as part of the assembly process. Alternatively, a handle-shaped pattern may be cut out of the bag, resulting in an integral handle without require further elements to be added.  
         [0022]     To assemble the bag, the pattern  10  is placed into a machine, which applies the glue spots and folds the pattern  10  in the proper sequence to assemble a finished bag. According to the pattern shown, the folding sequence runs top, sides, and bottom. If a handle is to be inserted, it is preferably done either as part of the top edge folding and gluing sequence, or as a separate process after the bag is completed, to ensure that the handle is fully integrated into the bag. Similarly, the reinforcing cardboard (or similar piece) is inserted and glued to the bottom as part of the bottom folding and gluing sequence.  
         [0023]     The stages of the folding process are shown in greater detail starting with  FIG. 2 . Tabs  20  and  22  are folded over in the direction of the arrows and secured by glue spots  200  and  202 . Next, the entire top edge  24  is folded over and secured by glue spots  204  to create the reinforced top edge of the bag. Holes  26  provide a location to attach a handle, if one is desired. Alternatively, the pattern  10  may include a cut-out handle location. Other known handles for bags can be similarly used.  
         [0024]     As shown in  FIG. 3 , the next step is a z-fold of the side  30 . The z-fold enables the side of the bag to be collapsed flat for assembly and shipping, and then be expanded upon use to create the bag. The folds proceed in the direction shown by the arrows. Once the z-fold is complete, the opposing side  40  is similarly z-folded and the front plane  42  is folded over and glued to the first side  30  by glue spot  400 , completing the body of the bag, as shown in  FIG. 4 .  
         [0025]     As shown in  FIG. 5 , the bottom panels  50 ,  52  and  54  are unfolded in preparation for completing the bottom of the bag. If desired, a reinforcing panel  60  is inserted at this step, as shown in  FIG. 6 . The reinforcing panel includes glue spots  600  for securing panels  52  and  54 , which are folded over in the direction of the arrows shown in  FIG. 7 .  
         [0026]     Bottom panel  56  is folded over and glued to panels  52  and  54  via glue spots  800 , and then bottom panel  50  is folded over and glued to panels  52 ,  54  and  56  via glue spots  800  and  900 , as shown in  FIGS. 8 and 9 , respectively.  
         [0027]     The result is that the fully assembled and ready-to-use bag comes out of the machine, complete with glued seams and a reinforced bottom and top, and including a handle, if desired.  
         [0028]     Also, while not explicitly shown in the drawings, any additional edges, surfaces or seams can be secured by using additional glue spots in suitable locations on the pattern as required.  
         [0029]     The placing of the glue spots relative to the timing of the folds is not essential to the process. Depending on the type of glue used, it may be preferred to place all the glue spots prior to folding. Alternatively, glue spots may be applied as necessary during each step of the folding process.  
         [0030]     As many of these types of containers, particularly the bags, have printed or applied images to the surfaces, it is further noted that the glue spots may be applied either before or after the printing/application process.  
         [0031]     While traditionally the bags have been made from paper or cardboard, advances in modern materials technology have created the possibility of making containers from other lightweight, resilient and foldable materials, such as metallic films and thin plastics. The folding and gluing process claimed herein is considered generally applicable to any of these materials, although it is acknowledged that in some instances the process may be inferior to other methods or generally unsuitable. Each material and method may require testing to determine optimal size and location for the glue spots, and possible the type and strength of glue, as described above.  
         [0032]     This concludes the description of a presently preferred embodiment of the invention. The foregoing description has been presented for the purpose of illustration and is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching and will be apparent to those skilled in the art. It is intended the scope of the invention be limited not by this description but by the claims that follow.