Field Of Invention

The present invention relates to the apparatus and method of making side gusseted bags with valve. More particularly, the inventions involve high speed automated production of gusset bags with valve.

Background Of Invention

Bags or sacks have been in use for packing/storage/ transportation of materials such as food grains, flour, and industrial materials of all kinds. These sacks can take on different shapes, such as pillow and box shapes. A pillow shape is typically created by manufacturing the bottoms with seams. A box shape is created by folding and bonding the bottom into a block form. Those of skilled in the art will understand that a box shape optimizes use of the material surface, facilitates stacking, and provides improved utilization of volume due to its brick shape.

However, the main drawback of box type bags is that they involve complex mechanism that is difficult to manufacture as well as very costly. Thus, requirement of pillow shape bag with some of the features of the box-type bag features evolve. Such box type features can be incorporated in the pillow shape bag by making the side gusset in the pillow shaped bag. These multi-layer bags when filled form flat side which makes the bag possible to stack stably on a loading pallet and thus acquiring lesser space as well. Such bags when manufactured involve less complex mechanism and are cost effective.

In the processing of woven fabric for making sacks for packing applications, it is common to form valves for fast filling material such as cement or any other kind of powdery or granular raw materials such as sand, grain etc. into sacks. Conventionally, these valves are formed manually by opening the sacks at their one comer and forming a filling mouth. These conventional methods of making valves or creases at one end of tubular sacks are time consuming, especially as the production demand for the bags/sacks with valves increases. So, there is a requirement of automated method of making valve in such bags.

One such side gusset bag is disclosed in US patentUS101796B2 (‘8796). The patent (‘8796) discloses a bag with front and back face panels having upright longitudinally extending side edges and transversely extending upper and lower edges. First and second gusset panels each have transversely extending upper and lower edges and upright longitudinal outer edges connected to the longitudinal edges of the face panels. A re-closable fastener strip extends continuously and transversely along the first gusset panel and inward along each of the face panels from the first gusset panel along part of a transverse width of the face panels. Thus, opening of the fastener and folding out of the first gusset panel forms a spout on the bag. A separate generally rectangular floor panel is joined at its outer edge by thermal welds to the lower edges of the face panels and of the gusset panels. However, the above bag disclosed in the patent (‘8796) does not have valve for filling the material or the above patent does not disclose anything about the apparatus of manufacturing such bag. In such condition a separate closing unit is required with is used to close the bag after filling. Thus, there is requirement of valve arises in the gusset type bag for faster filling rate.

However, a side gusseted polymer bag with a filling valve and its method of manufacture are known including a tubular body with opposed side gussets defining front and rear panels, and a filling valve formed by folding the front and rear panels with the interconnecting gusset portion at one comer of the bag inwardly into the bag forming a filling panel, and thereafter simultaneously sealing the top edges of the front and rear panels with the top edges of the filling panel forming a filling tube and valve that closes itself under the force of material as it rises in the bag. One such bag is disclosed in Patent US 6997858B1 (‘858). The Patent (‘858) further discloses gusseted poly bag with valve, which is heat sealed at the end, where side gusset bag with valve is made. The heat-sealed method of sealing bag end may provide good sealing joints to the poly bag but in case of woven fabric it will not provide a strong sealing joint or rather requires a special type of sealing joint to seal the gusset type bag. However, the Patent (‘858) does not disclose any apparatus of manufacturing the gusseted poly bag and at the same time involves a complex method folding poly bag along the fold lines manually to make a bag which is time consuming and decrease the rate of production. It further refers that as of present date there is no automated system or machine to manufacture such kind of bag.

Another patent CA627439 (‘439) discloses a bag with one side gusset and a valve. The patent (‘439) discloses multi wallpaper valve bag which has gusset at one end only, thus while fding the material there will be inadequate bulging of the side walls of the bag, as the both the side wall of the bag are not identical in construction. Patent (‘439) discloses a concept of the gusset bag with valve but does not address the automated process to manufacture the same.

However, the above patents discloses either non-woven bags with valve or paper or of same kind of bags with valve. The prior arts dose not discloses anything about automated method and apparatus of production of valved bag for woven packaging bag formation.

Thus, there is requirement of automated system or apparatus and a method to produce side gusseted bag with valve which are economically manufactured with high production rate.

Objects of Invention:

The main object of the present invention is to provide an automated method and an apparatus for manufacturing side gusset bag with valve. Another objective of the present invention to provide a bag with side gusset bag with valve with sealed at ends.

Further objective of the present invention is to provide an apparatus making side gusset bag with valve on automated bag manufacturing lines that operate at high speed.

Brief Description of Figures:

Figure 1 shows various units of the present invention and process of making side gusset bag with valve

Figure 1A shows a formation of gusset cut piece from tubular fabric

Figure 2 shows the block diagram of the process of manufacturing side gusset bag with valve

Figure 2A shows the schematic diagram of various units/devices of the apparatus of the invention

Figure 3 shows the bag of invention

Figure 4 shows the ‘L’ shaped bag cut piece

Figure 4A shows the valved bag with valve height and valve depth

Figure 5 shows the valve forming unit

Figure 6 shows the second cutting unit used for L shaped cut at the second end of the bag cut piece.

Figure 6A shows the Opening & Inward folding unit with opening and inward folding linkage used for valve formation.

List of Parts:

1. Cut piece of gusseted fabric 2B First sealed end

1A First Layer of fabric 3. Second end of fabric

IB Second layer of fabric 3A Second folded end

2. First end of fabric 3B Second sealed end

2A First folded end 3C Cut at second end 4. Suction means D. First Sealing unit

5. Gripper E. Conveying unit

6. Tubular fabric without gusset F. Second cutting unit

7. Inner tool G. Opening & Inward folding 8. Pivot 25 unit

9. Valve H. Pressing unit

10. Gusseted valve bag I. Eco cutting unit

11. leading edge J. Second folding unit

12. Trailing edge K. Second sealing unit 13. Pusher tool 30 L. Stacking unit

14. Second pivot X. Transpose cutting length

15. First cutting blade Y. Traverse cutting length

15 A. Second cutting blade LI. Bag length

16. Opening and inward folding LC. Cut piece length with first linkage 35 sealed end

17. Valve forming unit W. Bag width

18. Side inserting tool D. Gusset depth

A. Web puller unit VH. Valve height

B. First Cutting unit VL. Valve length C. First Folding unit

Summary Of Invention:

In accordance, with the present invention, there is provided a side gusseted bag with a filing valve and its method of manufacturing on an automatic machine. The gusseted fabric comprises of multi-layer structure which can be produced from weaving machine by inserting side gusseting tool and thereby winding over the roller. Such roll is transferred to the bag making machine for production of bag. However, such process of making gusset fabric roll can be attached in-line with the bag making machine in order to reduce the downtime of roll transferring. In addition to it, such fabric with side gusset can also be obtained from flat fabric with single flat ends on the bag making machine thereby forming a tube structure and simultaneously installing side gusset tool just after the unwinding station. Arms/tools are made to insert into the tubular fabric from sides such that it folds the tubular fabric inwards making the construction as multi-layered. The method to manufacture side gusset from the tubular fabric without gusset (6) is shown in figure 1A where the tubular fabric without gusset (6) is unwounded from the roll and passed through side inserting means (18) which are inserted or provide sideways pressure to the tubular fabric to form an inward fold into multilayer fabric known as gusset fabric. The fabric thus obtained is gusseted fabric which can be cut by the first cutting unit (B) into predetermine length to form a cut piece of gusset fabric (1) or is made to transfer to the main machine unit where it is pulled by the web puller unit and transferred to the cutting region. Then the cut piece of the gusset fabric (1) is transferred to the bag folding region where one of the ends of the bag namely first end (2) is folded and sealed. Such kind of sealing can be done by stitching or by application of glue or hot air welding application. The conveyor unit conveys the gusseted cut piece of the fabric for further processing. Now, at the second end (3), a ‘L’ shaped cut is made on the second end of the fabric at second cutting unit (F) with the help of the first and second cutting blades (15, 15 A) moves in the traverse and transpose direction to get the desired cutting on the bag edge. This type of cut provides an ease in manufacturing of valve in the later stages due to ease in the edge folding during valve formation.

After L shaped cut, the bag is transferred to the opening and inward folding unit where the upper and lower layers of the fabric are opened (or separated from each other) by a suction means such that a space is created for tool insertion. Set of inner tool moves in the plane of the fabric to form a valve as soon as it inserted inside by pivoting about the first pivot, inner tool start changing its plane by pivoting about the second pivot to facilitate the valve formation. Simultaneously, a pusher tool presses the valved formed due to inner tool motion to retain the valved shape. Then the cut piece of the gusseted fabric with valve is transferred to the pressing unit where in the top and bottom layers of fabric with valve is pressed by pressing unit to apply uniform pressure such that crease formation takes place. Further cutting of the cut piece of the gusseted fabric from the second end is performed in order to get the bag of desired length.

Now the second end of the cut piece of the gusset fabric is folded and sealed. Such kind of sealing can be performed by stitching, glue application or hot air welding. Finally, the gusseted bag with valve produced is stacked and stored.

The bags thus obtained may be made from a web sheet with more than one layer, comprises of a front wall, a back wall, a first side wall, a second side wall, an interior surface, an exterior surface, a top end, and a bottom end. The web sheet comprises a first layer made of a woven polymer or optionally non-woven polymeric web and a second layer made of adhesive coating or extrusion coating which is made from any material such as polypropylene, polyethylene, polyethylene terephthalate, polyamide, or any combination thereof, or paper.

Optionally, a third layer is provided which comprises oriented polypropylene, biaxially-oriented polypropylene, oriented polyethylene, biaxially-oriented polyethylene, oriented polyethylene terephthalate, biaxially-oriented polyethylene terephthalate, oriented polyamide, biaxially-oriented polyamide, coated paper or any combination thereof.

In an embodiment, the third layer is of BOPP lamination film with high end graphics or printing, such that it formed three layered structured bags. In further Embodiments, the bag comprises of at least two layers such that first layer is made of a woven polymer or optionally non-woven polymeric web over which a second layer which is formed by coating is laid. Further, it is possible that the second layer comprises a printed area such that printing can be done by use of any such known printing methods performed by any other printing machine. Detail Description Of Invention:

As shown in Figure 1, the gusset fabric is unwounded from a roll (a) and cut into cut piece of the fabric (1) by the first cutting unit (B). Instead of using gusseted fabric roll we can also use simple tubular fabric roll and convert them into the gusseted fabric before entering the cutting unit (B). Cutting can be done by hot cutting or cold cutting depending upon the fabric. The cut piece of gusseted fabric (1) comprises of first end (2) and second end (3) as shown in (b). The fabric (1) is passed over the conveying system (E) and transferred various bag formation units such as the bag folding section where first end of the fabric (2) is folded to form first end (2A) as shown in (c) which is sealed to form a first sealed end (2B) as shown in (d). The sealing can be done by sewing, hot glue application or by hot air welding application, such that first sealed end (2B) is properly sealed and is leak proof. Now, at the second end of the fabric (3) a cut (3C) is made by second cutting unit (F) as shown in (e). The cut thus formed is ‘L’ shaped so that the valve formation at later stage can be made easily.

The ‘L’ shaped cut is made at the second end of the fabric (3) such that a rectangular portion of the fabric is removed from the leading edge (11) which is far away from the trailing edge (12) as shown in figure 4. Cutting of the rectangular cut piece is completed with the help of the first and second cutting blade (15, 15 A) moving in the transpose and traverse direction simultaneously as shown in the figure 6. First cutting blade (15) moves in the linear transpose direction to form a transpose cutting length (X) with the help of the pneumatic cylinder. Simultaneously second cutting blade (15A) moves in linear traverse direction to form a traverse cutting length (Y) with the help of another pneumatic cylinder. Accuracy of linear motion of the pneumatic cylinder achieved with the help of the proximity sensor. Also, the movement of the cutting blades (15, 15 A) in linear transpose cutting length (X) and linear traverse cutting direction (Y) can also be achieved with the help of the liner motor or any other liner actuator or any kind of mechanical arrangement such as ball screw movement. After the removal of the rectangular cut piece from the leading -edge (11), bag cut piece moves toward the fabric opening & Inward folding unit (G). As the bag reaches the fabric opening & inward folding unit (G), the suction means (4) opens the fabric such that the first layer of fabric ( 1 A) and second layer of the fabric (IB) are apart from each other to form a mouth such that angle between the two layers of the fabric is near to 180 degrees as shown in Figure 1(f). The suction means (4) comprises of grippers (5) which holds the first and second layer of fabric (1A, IB) separately which the help of vacuum or any mechanical gripping arrangement such that the first and second layer are far apart to form a mouth.

As shown in figure 6A, the opening and inward folding unit further comprises opening and inward folding linkage (16) with the pair of upper and lower inner tools (7) which are identical in construction are inserted inside the bag from the trailing edge (12). The pair of inner tools (7) is required such that the each of the inner tool carries the fabric attached with first and second layer of fabric separately to form a perfect valve. As further shown in figure 6A, inner tool (7) is specially designed bended profile and is inserted in between the upper layer of the gusset fold and inner layer of the bag cut piece (1). The opening and inward folding linkage (16) comprises of set of inner tools (7) which is first pivot (8) mounted and swings about the same first pivot (8) by an angle (6). The angle (6) can be in the range of 85-90 degree or more particularly very close to 90 degree such that the valve is made perfectly as shown in (g). The swinging about a first pivot (8) can be achieved by pneumatic actuated rack and pinion cylinder or can be performed by using air cylinder or any kind of rotator motors or mechanical arrangement with provide an accurate rotational movement.

The opening and inward folding linkage (16) as shown in figure 6A, further rotates about a second pivot (14) with its axis parallel to the transpose direction. This second pivot (14) motion of the opening and inward folding linkage (16) along with the set of upper and lower inner tool (7) about the axis parallel to the transpose direction make the bag second end of fabric (3) in triangular shape by moving 90 degree and achieved the plane traverse to the conveying plane. This motion is achieved with the help of the pneumatic cylinder.

After that pusher tool (13) presses the triangular formation of the bag to retain the shape. This triangular shape formation at the second end (3) of the fabric helps in the valve formation. In next step second pivot (14) motion around the axis parallel to the transpose direction takes place and inner tools again regains its original plane of bag conveyor. After that set of inner tools (7) which is first pivot (8) mounted and swings about the same first pivot (8) by an angle (0) in the direction opposite to the initial one. Hence valve is formed at the second end (3) of fabric. Then valve formed at the second end of the bag moves to pressing unit (H) where bag is pressed to retain the shape before sealing the second end (3) of fabric at second folded end (3A). After valve (9) formation and pressing second end (3) of the fabric, bag moves to an optional eco cutting unit (I) height of the valve is adjusted by cutting the second end (3) of fabric, cutting extra fabric such that desired bag length can be achieved. After that second fold (3 A) as shown in (h) is made by folding device and sealed to form second sealed end (3B) as shown in (i). The sealing can be done by sewing, hot glue application or by hot air gun, such that second sealed end (3B) is properly sealed and is leak proof.

Figure 2 shows the block diagram comprising of various units involve in the manufacturing of the side gusset bag with valve (10). Side gusset fabric is pulled by the web puller unit (A) and transferred to the First cutting unit (B) where cut piece of the gusset fabric (1) is obtained. The First folding unit (C) folds the first end (2) of the fabric which is sealed by the First sealing unit (D). Now the fabric is transferred to another cutting unit, namely a second cutting unit (F) by conveying unit (E) to form a L shaped cut. Cut piece closed at one end is now transferred to the opening & inward folding unit (G) at one of the sides takes place to make a valve. Next the pressing unit (H) presses the fabric such that valve is formed perfectly, and crease formation takes place. An optional cutting unit is present named as Eco cutting unit (I) for cutting extra fabric such that desired bag length can be achieved. In Eco cutting, the second end of the fabric is made to cut such that overall length of the fabric can be set. Now the second folding unit (J) folds the second end (3) of the fabric which is sealed by the second sealing unit (K) and such bag made is side gusseted bag with valve at one end is now stacked on the stacking unit (L).

Figure 2A shows another schematic diagram of the complete machine consists of web puller unit (A) which consist of gusseted fabric roll and unwind the fabric according to the machine line speed and transferred to the First cutting unit (B) where cut piece of the gusset fabric (1) is obtained by cutting them into the desired length required for the formation of valved bag. Up to this stage fabric/ cut piece moves in the traverse direction as shown in Fig. 2A. After First cutting unit (B) bag moves 90 degrees in transpose direction. After that, first folding unit (C) folds the first end (2) of the fabric which is sealed by the sealing unit (D). Now the fabric is transferred to the second cutting unit (F) by conveying unit (E) to form a L shaped cut. Cut piece closed at one end is now transferred to the opening & inward folding unit (G) at one of the sides takes place to make a valve. Next the pressing unit (H) presses the fabric such that valve is formed perfectly, and crease formation takes place. An optional cutting unit is present named as Eco cutting unit (I) for cutting extra fabric such that desired bag length can be achieved.

As shown in figure 5, valve forming unit (17) comprises of second cutting unit (F), opening and inward folding unit (G), punching/pressing unit (H) and conveying unit (E). The figure 5 further shows the direction of movement of cut piece (1) such that it enters the second cutting unit (F) and leaves the pressing unit (H) to form a valve.

Figure 3 shows the bag of the present invention. A side gusset bag with valve (10) is shown wherein valve (9) is made is at the second end (3) of the fabric. The bag (10) further has first end (2) and second end (3) as a sealed end comprises of leading edge (11) which is close to valve (9) and trailing edge (12) which is far away from the valve.

Figure 4 shows the bag with the ‘L cut at the second end of the fabric (3) having a length (LC) which is obtained after the first folding and sealing at the first end of the fabric (2), gusset depth (D), transpose cutting length (X), traverse cutting length (Y).

Figure 4A shows the bag of length (LI), Width (W), Valve Height (VH) & Valve Length (VL). Valve length (VL) must be equal to summation of difference of bag width (W) and transpose cutting length (X) to the traverse cutting length (Y). Additionally, this Valve Height (VH) is equal to the summation of difference of bag width (W) and transpose cutting length (X) to gusset depth (D) reduced by 35 (mm).

VL = (W - X) + Y VH = ((W - X) + D) - 35

Below given table provided the range for the bag dimensions:

The above bag dimensions are selected to optimise the automated bag manufacturing through the inventive apparatus such that operator will get the production rate of 25-30 bags /min. At lower production speed the person skilled in art can alter the range of bag dimension provided above in the table. As a preferred embodiment of the present invention, the following steps are involved in the manufacturing of such kind of bags as shown in the figure 3:

• Side gusset fabric roll is unwounded from a roll.

• Cut piece of gusset fabric (1) is obtained from the gusseted fabric by first cutting unit (B).

• The cut piece of gusseted fabric (1) conveyed on conveying unit (E) is folded at the first end (2) and sealed by the first sealing unit (D) to form first sealed end (2A).

• Cut at the second end (3) of L shaped is made at the second end (3) of fabric by the second cutting unit (F) with the help of the first and second cutting blade (15, 15 A) moving in the transpose cutting direction obtaining transpose cutting length (X) and traverse direction obtaining traverse cutting length (Y) simultaneously.

• Opening & inward folding unit (G) open the two layers of the fabric (1A, IB) with the help of swinging movement of opening and inward folding linkage (16) about a second pivot (14) and simultaneously movement and swinging action of the inner tool (7) about a first pivot (8) form a valve (9).

• Simultaneously pusher tool (13) presses the valve for even formation about the bag plane.

• After that bag moves to the Eco cutting unit (I) for cutting extra fabric such that desired bag length can be achieved.

• Further the second end of fabric (3) is folded at second folding unit (J) to form a second folded end (3A) and sealed at second sealing unit (K) to form a second sealed end (3B).

• Thus, the bag with side gusset and valve (10) at the one of the ends is made.

General Clause regarding non limiting the scope of the invention within the embodiments of the invention.

While the above description contains much specificity, these should not be construed as limitation in the scope of the invention, but rather as an exemplification of the preferred embodiments thereof. It must be realized that modifications and variations are possible based on the disclosure given above without departing from the spirit and scope of the invention. Accordingly, the scope of the invention should be determined not by the embodiments illustrated, but by the appended claims and their legal equivalents.