An apparatus and a method for opening the ends of tubular web pieces

Abstract

An apparatus and a method for opening the ends of tubular web pieces (2) to make squared or block bottoms is disclosed. The apparatus comprises a pre-opening device (1A), upper and lower plates (21, 22) adjustable with a knob (6) to create a flexible opening (23) through which a cut tubular web piece (2) of wide range of variation in gsm can travel in the direction of movement of fabric (5). There are a set of vacuum belts (4, 4A), upper and lower guide elements (7 A, 7B), a set of gears (11,12,13,14) which are driven by a motor (10), and a splaying unit (IB) having first and second splaying elements (8,9) that enter the opening at the end of cut piece (2) and gradually and continually spread apart from each other, the layers of web pieces (2) at open end of the cut tubular piece to form a block bottom.

Description

[0001] AN APPARATUS AND A METHOD FOR OPENING THE ENDS OF

[0002] TUBULAR WEB PIECES

[0003] Field Of Invention

[0004] The invention relates to an apparatus and a method for opening the ends of tubular web pieces to make squared or block bottoms.

[0005] Background Of Invention

[0006] The production of block bottom bags usually comprises providing tubular web material which is either obtained by producing tubular material webs or by joining the longitudinal edges of flat material webs to obtain a tubular configuration, cutting the tubular material so as to obtain bag bodies of suitable length, and forming a bag bottom by appropriately folding over and closing one end of the bag body. A bag having a rectangular bottom produced in this way is usually called a box -type bag by specialists in the field.

[0007] In order to form the bottom of such a box-type bag, the end part of one of the two bag body walls lying on top of the other in a flattened bag body is folded over along a folding line running transversely to the longitudinal axis of the bag body, so that the end of the bag body takes a hexagonal folding configuration with two parallel seams opposing each other and two pairs of parallel folding edges opposing each other. By folding the two seams towards each other and securing the folding lobes comprising the seams to each other or to a cover sheet the bag body is provided with a bottom which takes a rectangular configuration when the completed bag is folded apart. It is also possible to apply a valve sheet before folding the seams towards each other, which valve sheet takes a tubular configuration when folding the bag body end to its final shape.

[0008] Devices for opening ends of tubing to open bottom squares are already known and are part of bag / sack making devices. Here the bag / sack making devices that can handle pieces of tubing made of any materials, preferably pieces of plastic, are processed on the devices described below, in particular those comprising woven fabric of stretched plastic tape.

[0009] An apparatus for producing sacks has been disclosed in the patent application DE 19502251 Al which describes a bottom opening device in which a piston rod which carries a slider means for opening the bottom squares is provided. This slider is moved to a raised position and at the same time extended into the tube piece plane in order to fold over the upper wall of a piece of tubing along the fold line on itself. Subsequently, the slider is lowered in the extended position to press the wall, and then retracted again. For the slider to work properly, it is necessary that the piece of hose to be opened is at rest. A supplied piece of tubing must therefore be stopped first. After the bottom has been opened, the tube piece must be accelerated again to be transported to the next processing station. However, a bottom-ends- opening device as disclosed in the said DE 19502251 Al proves to be disadvantageous as it is too slow because the process takes place in two steps: First the crease formation wherein the fabric needs to be stopped for processing and then it is transferred to the second step for triangle formation. This is a stop- and-go method. In addition, such a device is susceptible to wear due to the involvement of many parts in the fabric process at multiple stations.

[0010] Another DE application No DE912045 discloses a device for cross bottom bag machines, in which a sickle-like bottom laying stick or a sickle of a drive has been used, which consists of the machine drive and two gears is being driven. This bottom laying stick / sickle, which can be referred to as means for opening in the sense of the said patent application moves at least partially in the transport direction and in the extension direction of the hose pieces. The gears and the machine drive can be considered as a first means of moving. However, the sickle like bottom laying stick / sickle touches the hose piece only at certain points, so that pieces of hose, especially if they include tissue plastic tapes are often not opened safely and properly in required shape whereby the fabric is not adequately protected from wear and tear during the opening of the ends.

[0011] In addition, in the prior art, bottom opening stations were used with rotating spreading tools with an upper part and a lower part, which are moved apart during the orbital movement of a mechanism. However, such multi-part spreading tools are disadvantageous as they are structurally complex and error- prone. In addition, extensive settings are required for such spreader tools.

[0012] Yet another example of bag opening apparatus is disclosed in EP3148788A1 (‘788) where in a device and method to form bottom opening between the bags section is shown with the cluster of wedges elements having complex geometry. It is further disclosed in patent (‘788) that these wedge elements are driven by a common drive. The main drawback of the said invention is that there is no setting of wedge elements to accommodate wide range of bag. Another drawback of the invention disclosed in (‘788) is that the bag bottom wide cannot be altered while machine is running. Yet another drawback with respect to the invention (‘788) is that when all the wedge elements are driven by a single drive, there is no possibility of correcting errors if aroused during bag making process by the movement of wedge elements.

[0013] Other devices for opening tube bottoms are also disclosed, for example, in US 6328683 or US 6042526, however such devices are unable to meet the requirement of bottom opening ends at high speed and rapid adjustment for accommodation of different size of opening and tubular web width. Further, such devices involve very complex process and movement of various components which reduces overall efficiency and accuracy of the system.

[0014] Other devices for opening tube bottoms are also disclosed, for example, in WO / 2021 / 229395, The invention relates to an apparatus and a method for opening ends of tubular web pieces to make squared or block bottoms. Apparatus comprises an end opening device, two rotating differentials positioned angularly to the plane of web pieces. Each differential has a shaft on which a pair of splaying elements formed by shaping bars into curvilinear shape is mounted. Splaying elements form a three-dimensional virtual shape upon rotation. Individual layers of the bag body at its open-end portion are spread apart by guiding elements of opening device near one corner to form an opening at the bottom into which one of the splaying elements is inserted. Continued rotational motion of drives ensures that both splaying elements enter the opening and gradually and continually spread apart from each other the layers of web pieces at open end to form a block bottom. However, this system also has some drawbacks. First drawback is that the fixed gap between the upper and lower guide element at the entry of the tubular web piece due to which there is no flexibility in the gap at the entry and hence does not allow to use fabric with wide range of variation in gsm. Yet another drawback of the invention disclosed is that it does not support fabric after the bag opening which leads to deformation under gravity.

[0015] Therefore, there is a requirement of opening device which obviates the above- mentioned drawbacks with proper supporting profiles which can operate at high speed, at lower maintenance cost and adjustable in nature which has ease of setting for different material specification.

[0016] Objects Of Invention:

[0017] The main object of the present invention is to provide an apparatus for opening the ends of tubular web pieces which provides flexibility in the gap formation at the entry that allows to use fabric with wide range of variation in width..

[0018] Another object of the present invention is to provide an apparatus for opening the ends of tubular web pieces which provides the support to the fabric after the bag opening so as to prevent the deformation of the bag under gravity and also to prevent the bag from tear and wear. Yet another object of the present invention is to provide a method for opening the ends of tubular web pieces which is quite convenient and simple and can be performed at high speed, at lower maintenance cost and has ease of setting for different material specification.

[0019] Brief Description Of Figures:

[0020] Figure 1 shows the perspective view of bag opening unit.

[0021] Figure la shows the process of opening bag ends

[0022] Figure 2 shows the front view of initial opening by guide elements of the present invention.

[0023] Figure 2a shows the back view of initial opening by guide elements.

[0024] Figure 3 shows the perspective view of splaying unit.

[0025] Figure 4 shows the embodiment of splaying element of the present invention.

[0026] Summary Of Invention

[0027] According to the present invention, an apparatus for opening a bag end is provided. In an automated bag making line, a number of processes are carried out by which a tubular or a flat fabric is converted into a bag. A number of stations are provided to carry out these processes. Some of these are:

[0028] • Web roll feeding means wherein woven or non-woven fabric roll is loaded to feed the fabric in forward direction

[0029] • Web edge guiding and unwinding means wherein the fabric is guided over rollers and unwinds from the fabric roll

[0030] • Web fabric preparatory means optionally consisting of either web perforation means which removes all the air traps between the layers of the fabric for smooth operation or index hole punching means or both.

[0031] • Web cleaning means

[0032] • Inspection and sensing means which senses the quality of the fabric

[0033] • Web cutting means for cutting the fabric in required bag length • Transportation means for transporting the web pieces towards different zones of bag manufacturing

[0034] • Traverse transfer and guiding / feeding means which changes the direction of web pieces from longitudinal to transverse for bag formation

[0035] • Defect Rej ection means to identify the defective fabric before bag formation

[0036] • Top and bottom edge opening means wherein both the sides top and bottom edge of fabric is opened or folded

[0037] -the edge opening means vertically position -Opening means have rotary mechanism

[0038] • Valve patch storing, conveying & pasting means wherein a patch is applied on the folded fabric before making the valve

[0039] • Folding means which folds the fabric edge with valve patch to form a valve

[0040] • Further transporting means to further transport the bag with valve at one end to the other stations

[0041] • Stacking means for storing the final bags

[0042] The apparatus of the present invention is designed to provide opening at the bag ends on an automated line comprises of two rotating drives positioned angularly with respect to the plane of movement of the cut pieces of web. Each of the rotating drives has a shaft on which a splaying element is mounted. The splaying elements are formed by shaping bars or rods into a curvilinear shape. Each splaying elements consist of several fingers which are parallel to the axis of rotation of the respective splaying elements and placed at the periphery of the curvilinear shape of the splaying element. These fingers facilitate the bag opening by increasing the support area for opening and all these fingers also consist of rubber like bands or tubular elements attached at the end of the fingers to prevent bag from damage. The fingers are placed in the periphery of the splaying element and placed parallel to the axis of the splaying elements which result into the conversion of disc like splaying elements into the cylindrical element which further results into the significant increase in the support area for fabric. The positioning of the two drives is such that during any full rotation of the individual splaying elements, a three-dimensional virtual shape is formed corresponding to each element. The two virtual shapes are partially annular relative to each other. During the transportations on the transport device, the individual layers of the bag body at the open-end portion of the tubular bag body is spread apart by the guiding elements near one comer to form an initial opening at the bottom.

[0043] To open the bag opening ends, one of the pair of raised contour shaped splaying elements is inserted into the initial opening. The continued rotational motion of the drives ensures that both splaying elements enter the initial opening and gradually continually spread apart from each other where the layers of the bag body at the open end is supported by the fingers continuously throughout the forming at opening unit to form a block bottom. Further, another pair of splaying element driven by separate drive presses the bag end to form hexagonal shape.

[0044] List Of Parts:

[0045] 1. Apparatus of invention 4A. Lower Vacuum Belt

[0046] 1 A. Pre-Opening Unit 5. Direction of movement of IB. Splaying Unit fabric

[0047] 2. Tubular web piece 35 6. Adjustable Knob 2A. Upper section 7. Opening device 2B. Lower section 7A. Upper guide element 2C. open end region 7B. lower guide element 2D. upper section of 7A’. Upper guide surface bottom opening 40 7B’. Lower guide surface

[0048] 2D’, lower section of 8. First Splaying element bottom opening 8A. Upper Splaying

[0049] 2E. web piece opening element primary 3. Conveyor table 8B. lower splaying element

[0050] 4. Upper Vacuum Belt 45 primary 9. Second Splaying element 15. Fifth Gear

[0051] 9A. Upper Splaying element 15 16. Idler Pulley secondary 17. Toothed Belt

[0052] 9B. lower splaying element 18. Second Motor secondary 19. Finger

[0053] 9C. Upper splaying opener 20. End rubber

[0054] 9D. Upper splaying support 20 21. Upper plate

[0055] 9E. lower splaying opener 22. Lower plate

[0056] 10. First motor 23. Opening

[0057] 11. First gear 24. Power Train

[0058] 12. Second Gear 25. Common axes

[0059] 13. Third Gear 25 26. Endless belt

[0060] 14. Fourth Gear

[0061] Detail Description Of Invention:

[0062] Since the state-of-the-art machines on the operating and drive side are constructed almost identically to be able to work simultaneously on both ends of the tubular piece, the following description does not deal in detail with the various sides of the machine. A previously cut piece of tubing is guided transversely to its longitudinal axis, that is perpendicular to the extension axis of the piece of tubing, by a suitable means of transport (for example double belt conveyor) to a pre-opening station. Figure 1 shows the apparatus (1) of the present invention in the context of a greater machine / plant used for opening the bag ends to form triangular formed profile consisting of pre-opening unit (1A) and splaying unit (IB), wherein a web material, is processed in various stations to form finished block bottom bags or block bottom valve bags. The machine comprises of various units, one of which is cutting unit (not shown) for the cutting or separating the web material into tubular web piece (2). As shown in Figure 1 A, a tubular web piece (2) that is used for making bags comprises two bag sections i.e., upper section (2A) and lower section (2B) lying one upon the other, where in each of the two sections (2A, 2B) can be constituted by a plurality of layers of different material. The tubular web piece (2) is transferred over a conveyor table (3) by a set of moving belts (4). Over the conveyor table (3), the tubular web pieces (2) are successively conveyed in the transport direction (5)to the splaying unit (IB), comprises of first splaying unit (8) and second splaying unit (9).

[0063] Figure 2 shows the front view of the apparatus of the present invention, which comprises of a pre-opening device (1A), an upper plate (21), a lower plate (22) and a conveyor table (3). The said upper plate (21) and lower plate (22) are adjustable with the help of an adjustable knob (6) such that an opening (23) is created for the tubular web piece (2) to travel easily in the direction of movement of fabric (5). In between the opening (23), bag is moved forward with the help of a set of vacuum belts, namely an upper vacuum belt (4) and a lower vacuum belt (4A), which stick the bag upper section (2A) and lower section (2B) for pre-opening.

[0064] This adjustable feature of the upper plate (21), lower plate (22) is one of the key features of the present invention which creates ease in the maintenance and assembly. Further, upper plate (21) and lower plate (22) are well connected by a common connecting link such that a required opening (23) is constant through the bag making process.

[0065] One of the embodiment of the present invention as shown in figure 2 and 2a which shows back view of initial opening by guide elements there is an upper guide element (7 A) and a lower guide element (7B) are provided in preopening unit (la) which are connected via meshing of third gear (13) and second gear (12) respectively and further second gear (12) is meshed with first gear (11). The first motor (10) is connected with a first gear (11) through a shaft such that the power and the rotational movement of the first motor (10) is transferred to the respective gears (13, 14) via direct meshing between second gear (12) and third gear (13) and another direct meshing between fourth gear (14) and fifth gear (15). Another embodiment of the invention is that an idler pulley (16) is also provided to adjust the belt tension of the toothed belt (17) in the mechanism. Such system of gear meshing ensures that the equal rotational speed is provided to belts of upper guide element (7 A) and lower guide element (7B). The equal rotational speed of the belts ensures identical and equal movement or opening of the upper section (2A) and lower section (2B) of the tubular web piece with respective to the movement of the fabric in transport direction (5). In a further embodiment of the present invention is that first splaying element (8) which has upper and lower splaying elements (8A, 8B) are provided which are capable of rotating about an axis in anti-clockwise direction by the same first motor (10) to penetrate inside the web piece opening (2E) from the open-end region (2C).

[0066] The upper guide element (7 A) has an upper guide surface (7A’) ascending upwards in transport direction (5) and the lower guide element (7B) has a lower guide surface (7B’) descending downwards in transport direction (5). Endless belts (26) are provided on guide elements (7A,7B), such that said endless belts being driven by a first motor (10) to provide rotational motion to the belts. Guide elements (7 A, 7B) are each connected to a suction element (not shown) for sucking associated bag section having upper suction belt (4) and lower suction belt (4A) running on upper guide element (7 A) and lower guide element (7B) respectively. This kind of suction method is very useful for the separation of bag layers from each other.

[0067] Figure 3 shows the second splaying element (9) consisting of a secondary upper splaying element (9 A) and a secondary lower splaying element (9B) used to open the bag. Continued rotational motion of drives with second motor (18) ensures that both splaying elements enter the opening and gradually and continually spread apart from each other, the layers of web pieces at open end to form a block bottom. A set of additional fingers (19) is provided on each of the secondary splaying elements (9A, 9B) to increase the supporting area after the opening while end rubber (20) is provided on each of the fingers (19) to prevent the bag from tear and wear.

[0068] In another embodiment, second splaying element (9) as shown in figure 4 which comprises of secondary upper splaying element (9A) consist of upper splaying opener (9C) and upper splaying support (9D), which are collectively responsible for the opening and forming of the upper triangle or upper section of bottom opening (2D) at the end of the bag. The upper splaying opener (9C) and upper splaying support (9D) are derived with the help of second motor (18) and power train (24). Power train (24) can be anything such as gear, pneumatic drive, or linkage mechanism to transfer power from the second motor (18) to the rotating upper splaying opener (9C) and splaying support (9D). The upper splaying element opener (9C) and upper splaying support (9D) are rotated around the common axis(25).

[0069] In this embodiment both upper splaying opener (9C) and upper splaying support (9D) are separated by small circumferential distance between them which depends upon the width of the bag opening. Circumferential separation between the splaying opener upper (9C) and upper splaying support (9D) is such that contact or support to the bag is given only at the time of opening of the ends and support. The circumferential size of the upper splaying opener (9C) and upper splaying support (9D) depends upon the size of bag width. Further, upper splaying opener (9C) open the upper section of bottom opening (2D) and upper splaying support (9D) support the formed triangle at the upper section i.e. at 2D. In the similar way, second splaying element (9) has secondary lower splaying element (9B) consist of lower splaying opener (9E) and lower splaying support (9F), which are collectively responsible for the opening and forming of the lower triangle or lower section of bottom opening (2D’) at the end of the bag.

[0070] As shown in figure la, the method for opening the ends of tubular web piece using the apparatus of the present invention to from bottom at the open ends which comprises of the following steps: a. Transporting the tubular web piece (2) over a conveyor table (3). b. Entering the said tubular web piece (2) into the opening (23) such that upper plate (21) and support lower Plate (22) form a barrier to upper section (2A) and lower section (2B) respectively and bag moves in the direction of movement (5) c. Sucking the said the two sections of tubular web piece by the upper guide element (7 A) and lower guide element (7B) passing over upper guide surface (7A’) and lower guide surface (7B’) respectively. d. Creating a web piece opening (2E) as the tubular web piece (2) advance further by movement of the guide surfaces (7 A’ , 7B’) by the first motor (10) and gears (12,13,14) arrangement. e. Simultaneously rotating first splaying elements (8) which has upper splaying element primary (8A) and lower splaying element primary (8B) about an axis in anti-clockwise by the same first motor (10) to penetrate inside the web piece opening (2E) from the open-end region (2C). f. Opening the upper section (2A) and lower section (2B) of web piece (2) with said first splaying elements (8) which has upper splaying element primary (8A) and lower splaying element primary (8B) g. Advancing the said tubular web piece (2) further and rotating the second splaying element (9) about an axis in anti-clockwise by second motor (18). h. Pressing the upper section of bottom opening (2D) with second splaying element (9) which has upper splaying element secondary (9 A) and the lower section of bottom opening (2D’) with lower splaying element secondary (9B) to open the tubular web piece (2) into block bottom opening.

Claims

Claims:

1. An apparatus for opening the ends of tubular web pieces (2) said apparatus comprising- a pre-opening device (1 A), an upper plate (21), a lower plate (22) and a conveyor table (3), wherein said upper plate (21) and said lower plate (22) are adjustable with the help of an adjustable knob (6) to create a flexible opening (23) through which said tubular web piece (2) of wide range of variation in gsm can travel in the direction of movement of fabric (5); a set of vacuum belts, namely an upper vacuum belt (4) and a lower vacuum belt (4A), which stick the bag upper section (2A) and lower section (2B) for pre-opening an upper guide element (7 A) and a lower guide element (7B) which are connected via meshing of third gear (13) and second gear (12) respectively and further second gear (12) is meshed with first gear (11); a first motor (10) connected with said first gear (11) through a shaft to transfer the power and the rotational movement of said first motor (10) is transferred to the respective gears (13, 14) via direct meshing between second gear (12) and third gear (13) and another direct meshing between fourth gear (14) and fifth gear (15); an idler pulley (16) to adjust the belt tension of the toothed belt (17); a splaying unit (IB) consisting of first splaying element (8) which has upper and lower splaying element (8A, 8B) rotatable about corresponding common axes (25) in anti-clockwise direction by said first motor (10) to penetrate inside the web piece opening (2E) from the open-end region (2C);- the said splaying unit (IB) further consisting of a second splaying element (9) which has further upper and lower secondary splaying element (9 A, 9B) wherein under the influence of the rotational motion powered by a second motor (18);wherein, said upper guide element (7 A) has an upper guide surface (7A’) ascending upwards in transport direction (5) and the lower guide element (7B) has a lower guide surface (7B’) descending downwards in transport direction (5), and wherein endless belts (26) provided on guide elements (7A,7B) are driven by a first motor (10) to provide rotational motion to the belts, wherein said guide elements (7 A, 7B) suck associated bag section having upper suction belt (4) and lower suction belt (4A) running on said upper guide element (7 A) and said lower guide element (7B) respectively; and said second splaying element (9) which has secondary splaying elements (9 A, 9B) enter the opening and gradually and continually spread apart from each other, the layers of web pieces at open end to form a block bottom.

2. The apparatus as claimed in claim 1, wherein said upper plate (21) and lower plate (22) are well connected by a common connecting link such that a required opening (23) is constant through the bag making process.

3. The apparatus as claimed in claim 1, wherein a set of additional fingers (19) is provided on each of the secondary splaying elements (9 A, 9B) to increase the supporting area after the opening while end rubber (20) is provided on each of the fingers (19) to prevent bag from damage .

4. The apparatus as claimed in claim 1 wherein said second splaying unit (9) consist of upper splaying opener (9C) and upper splaying support (9D) that derive power from second motor (18) and a power train (24) that transfers power from said second motor (18) and collectively form opening and forming of the upper triangle at the upper section of bottom opening (2D) at the ends of the bag. upper splaying element opener (9C) and upper splaying support (9D) are rotated around said respective common axes.

5. The apparatus as claimed in claim 4, wherein said upper splaying opener (9C) and said upper splaying support (9D) are separated by a circumferential distance that provides contact or support to the bag only at the time of opening and support.

6. The apparatus as claimed in claim 5, wherein the circumferential size of the upper splaying opener (9B) and upper splaying support (9C) corresponds to the bag width.

7. The apparatus as claimed in claim 1 wherein second splaying unit (9) consist of lower splaying opener (9E) and lower splaying support (9F) that derive power from second motor (18) and a power train (24) that transfers power from said second motor (18) and collectively form opening and forming of the lower triangle at the lower section of bottom opening (2D’) at the ends of the bag, and wherein said lower splaying element opener (9E) and lower splaying support (9F) are rotated around said respective common axes.

8. A method for opening the ends of tubular web pieces (2) using the apparatus as claimed in claims 1 to 7, wherein said method comprises the steps of: a. transporting the tubular web piece (2) over a conveyor table (3); b. entering said tubular web piece (2) into the opening (23) such that upper plate (21) and support lower plate (22) form a barrier to upper section (2A) and lower section (2B) respectively and bag moves in the direction of movement (5); c. sucking said two sections by the upper guide element (7 A) and lower guide element (7B) passing over upper guide surface (7A’) and lower guide surface (7B’) respectively.d. creating web piece opening (2E) as the tubular web piece (2) advance further by movement of the guide surfaces (7A’, 7B’) by the first motor (10) and gears (12, 13, 14) arrangement. e. simultaneously rotating first splaying element (8) which has upper splaying element primary (8A) and lower splaying element primary (8B) about an axis in anti-clockwise direction using a first motor (10) to penetrate inside the web piece opening (2E) from the open-end region (2C). f. opening with said first splaying elements (8) the upper section (2A) of web piece (2) and with said lower splaying element primary (8A) the lower section (2B) of web piece. g. advancing said tubular web piece (2) further and rotating said secondary splaying elements (9) about an axis in anti-clockwise direction by second motor (18). h. pressing with second splaying element (9) which has upper splaying element secondary (9 A) the upper section of bottom opening (2D) and with the lower splaying element secondary (9B) the lower section of bottom opening (2D’) to open the tubular web piece (2) into block bottom opening.

9. The method for opening the ends of tubular web pieces (2) as claimed in claim 8, wherein in step h the upper splaying opener (9B) opens the upper section of bottom opening (2D) and upper splaying support (9D) supports the formed upper triangle, and lower splaying opener (9E) presses the lower section of bottom opening (2D’) and lower splaying support (9F) support the formed lower triangle to opens the tubular web piece (2) into block bottom opening.

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