Apparatus and method for opening the ends of a tubular fabric piece to make a block bottom bag

Abstract

The invention relates to an apparatus and method for opening the ends of a tubular fabric piece (2) to make a square or square bottom. The apparatus comprises an end opening device (7), two rotating differentials (22, 26) positioned at an angle to the plane of the fabric piece (2). Each differential (22, 26) has an axis on which a pair of unfolding elements (8, 9) formed by forming a rod into a curved shape are mounted. The unfolding elements (8, 8A, 9, 9A) form a three-dimensional virtual shape when rotated. The layers of the bag body at its open end are unfolded by a guide element (7A, 7B) of the opening device (7) near one corner to form an opening at the bottom, into which one of the unfolding elements is inserted. The continuous rotational movement of the drive ensures that the two unfolding elements enter the opening and gradually and continuously unfold the layers of the fabric piece (2) at the open end to each other to form a square bottom.

Description

Technical Field

[0001] The present invention relates to an apparatus and method for opening the ends of a tubular fabric member to form a square or quad base. Background Art

[0002] The production of square bottom bags usually includes: providing a tubular fabric material, which is obtained by producing a tubular material fabric or by joining the longitudinal edges of a flat material fabric to obtain a tubular structure; cutting the tubular material to obtain a bag body of suitable length; and forming the bag bottom by appropriately folding and closing one end of the bag body. Bags with a rectangular bottom produced in this way are usually called box bags by professionals in the field.

[0003] To form the bottom of such a box bag, the end of one of the two bag walls superposed on each other in the flat bag body is folded along a fold line extending transversely to the longitudinal axis of the bag body, so that the end of the bag body adopts a hexagonal folded configuration with two parallel seams facing each other and two pairs of parallel folded edges facing each other. By folding the two seams towards each other and fixing the folded leaves including the seams to each other or to a covering sheet, the bag body is provided with a bottom that adopts a rectangular configuration when the finished bag is folded apart. It is also possible to apply a valve sheet before folding the seams towards each other, which valve sheet adopts a tubular configuration when the bag body end is folded into its final shape.

[0004] Devices for opening the ends of the tube to open the bottom square are known and are part of the bag / sack making apparatus. Here, the bag / sack making apparatus is processed on the apparatus described below, especially those comprising a woven fabric made of stretched plastic strips, which can process tubes made of any material, preferably tubes made of plastic.

[0005] A device for producing sacks has been disclosed in patent application DE 19502251 A1, which describes a bottom opening device in which a piston rod is provided which carries a slide member for opening the bottom grid. The slide moves into a raised position while extending into the plane of the tube in order to fold the upper wall of the tube along the folding line on itself. Subsequently, the slide is lowered in the extended position to press the wall and then retracted again. In order for the slide to work properly, the hose piece to be opened needs to be at rest. Therefore, the supplied tube must first be stopped. After the bottom has been opened, the tube must be accelerated again to be conveyed to the next processing station.

[0006] Yet, the bottom opening device disclosed in said DE 19502251A1 proves to be disadvantageous because it is too slow.In addition, this device is prone to wear.

[0007] Another German application No. DE912045 discloses a device for a cross-bottom bag machine, in which a sickle-shaped bottom laying rod or a sickle of a drive is used, which consists of a machine drive and two driven gears. In the sense of the patent application, this bottom laying rod / sickle, which can be called a member for opening, moves at least partially in the conveying direction and extension direction of the hose piece. The gear and the machine drive can be considered as the first moving member. However, the sickle-shaped bottom laying rod / sickle only contacts the hose piece at certain points, so that the hose pieces, especially when they include thin plastic strips, often cannot be opened safely.

[0008] Furthermore, in the prior art, bottom opening stations are used with rotating deployment tools having an upper part and a lower part, which move apart during the orbital movement of the mechanism. However, such multi-part deployment tools are disadvantageous because they are complex and prone to error. In addition, such deployment tools require a large number of settings.

[0009] Yet another example of a bag opening device is disclosed in EP 3 148 788 A1 ('788), wherein a device and method for forming a bottom opening between bag sections is shown, wherein a group of wedge-shaped elements have a complex geometry. It is further disclosed in the patent ('788) that these wedge-shaped elements are driven by a common drive. The main disadvantage of this invention is that no wedge-shaped elements are provided to accommodate a wide range of bags. Another disadvantage of this invention ('788) is that the bag bottom width cannot be changed during machine operation. Yet another disadvantage that can be stated in relation to the invention ('788) is that when all wedge-shaped elements are driven by a single drive, it is not possible to correct errors in the bag making process if they are caused by the movement of the wedge-shaped elements.

[0010] Other devices for opening the bottom of the tube are also disclosed in, for example, US 6328683 or US 6042526, however, such devices do not meet the requirements of a high speed and fast adjustment of the bottom open end for adapting to openings of different sizes and widths of tubular fabrics. In addition, such devices involve very complicated processes and the movement of various parts, which reduces the overall efficiency and accuracy of the system.

[0011] Therefore, there is a need for an opening device that can operate at high speed, with low maintenance costs, and is easily set up for different material specifications.

[0012] The present invention provides a device for bottom opening by which the disadvantages of the prior art are overcome and which is robust, reliable, requires little maintenance and allows production speeds much higher than those of the systems known in the prior art. Summary of the invention

[0013] Purpose of the invention:

[0014] The object of the present invention is to provide a bottom opening device which can be operated at high speed and with high precision.

[0015] A further object of the present invention is to provide an apparatus which can be easily arranged to process different types of tubular textile materials.

[0016] It is another object of the present invention to provide an apparatus and method for quickly adjusting to accommodate openings of varying sizes and widths of tubular fabrics.

[0017] Yet another object of the present invention is to provide a device which has minimal wear and tear and is easy to maintain.

[0018] A still further object of the present invention is to provide a device for producing a bottom opening with high precision and reliability in a continuous operation, wherein the device has a simple structure. Summary of the invention:

[0020] According to the present invention, there is provided an apparatus for opening the ends of bags. In an automated bag making line, several processes are performed to transform a tubular or flat fabric into bags. Several stations are provided to perform these processes. Some of these are:

[0021] ● Fabric roll feeding member, in which a woven or nonwoven fabric roll is loaded to feed the fabric in a forward direction

[0022] ● Fabric edge guiding and unwinding means, in which the fabric is guided on rollers and unwound from the fabric roll

[0023] Fabric preparation components, including:

[0024] - The preparation member optionally consists of a fabric perforating member that removes all air bubbles between the fabric layers for a smooth operation

[0025] - The preparation means may optionally consist of a graduated hole punching means

[0026] - Fabric cleaning components

[0027] ● Inspection and sensing components, which sense the quality of the fabric

[0028] Fabric length cutting member, which cuts the fabric into the required bag length

[0029] Conveying members that convey the fabric towards the different bag making areas

[0030] Transverse transfer and guide / feed members that change the direction of the fabric from machine direction to transverse direction to form bags

[0031] Defect removal means, which removes defective fabric before forming the bag

[0032] Top and bottom edge open components, where both sides of the top and bottom edges of the fabric are opened or folded

[0033] -Vertical positioning of the edge opening member

[0034] - Opening member with rotating mechanism

[0035] ● Valve patch storage, transport and application components where the patch is applied to the folded fabric before the valve is made

[0036] A folding member that folds the edge of the fabric with the valve patch to form a valve

[0037] A further conveying member, which further conveys the bag with a valve at one end to a further station

[0038] ● Stacking structure for storing bags

[0039] The device of the invention designed to provide an opening of the bag end on an automated bag manufacturing line comprises two rotary drives positioned at an angle relative to the plane of movement of the cut fabric piece. Each of the rotary drives has a shaft on which a pair of unfolding elements are mounted. The unfolding elements are formed by shaping a rod or a bar into a curvilinear shape. The two drives are positioned so that during any complete rotation of the respective unfolding element, a three-dimensional virtual shape is formed corresponding to each element. The two virtual shapes are partially annular relative to each other.

[0040] During transport on the transport device, the individual layers of the bag body at the open end of the tubular bag body are spread out by a guide element close to one corner to form an initial opening at the bottom.

[0041] To open the bag, one of the pair of unfolding elements in the shape of a raised profile is inserted into the initial opening. The continuous rotational movement of the drive ensures that the two unfolding elements enter the initial opening and gradually and continuously unfold the layers of the bag body at the open end to each other to form a square bottom. Further, another pair of unfolding elements driven by a separate drive presses the bag ends to form a hexagonal shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A perspective view showing a bag making line.

[0043] Figure 1A Flowchart showing the process of opening the bag end:

[0044] (a) Tubular cut fabric pieces;

[0045] (b) initial opening by a guide element;

[0046] (c) inserting a first expansion element to form an opening;

[0047] (d) pressing the opening form by a second unfolding element;

[0048] (e) A bag having an open end.

[0049] Figure 2 The device of the present invention is shown.

[0050] Figure 3 A perspective view of the opening device is shown.

[0051] Figure 4 , Figure 4A , Figure 4B The different stages of bag opening are shown including the initial opening stage.

[0052] Figure 4C , Figure 4D An enlarged view showing the opening of the bag by the unfolding element.

[0053] Figure 5 The deployment elements and their movement are shown.

[0054] Parts List:

[0055] 1: Equipment of the present invention

[0056] 2: Tubular fabric pieces

[0057] 2A: Upper section

[0058] 2B: Lower section

[0059] 2C: Open end area

[0060] 2D: Upper section with bottom opening

[0061] 2D': Lower section with bottom opening 2E: Fabric piece opening

[0062] 3: Teleportation Station

[0063] 4: Belt

[0064] 5: Fabric movement direction

[0065] 6: Longitudinal extension axis

[0066] 7: Turn on the device

[0067] 7A: Upper guide element

[0068] 7A': Upper guide surface

[0069] 7B: Lower guide element

[0070] 7B': Lower guide surface 8: First upper unfolding element

[0071] 8A: First lower expansion element

[0072] 8B: First wedge surface

[0073] 8C: First wedge-shaped extension

[0074] 8D: First wedge end

[0075] 8E: First wedge-shaped sleeve 9: Second upper expansion element

[0076] 9A: Second lower expansion element

[0077] 9B: Second wedge surface

[0078] 9C: Second wedge-shaped extension

[0079] 9D: Second wedge-shaped end

[0080] 9E: Second wedge-shaped sleeve 10: First motor

[0081] 11: First Gear

[0082] 12: shaft 13: second gear

[0083] 13A: First flanged pulley 14: Third gear

[0084] 15: Fourth gear 16: Fifth gear

[0085] 16A: Second flanged pulley 17: Idler pulley

[0086] 18: Toothed belt

[0087] 19: Mounting plate

[0088] 20: First rotatable axis

[0089] 21: The first adjustable base

[0090] 21A: Right arm

[0091] 21B: Left arm

[0092] 21C: Sliding tray

[0093] 21D: Adjustment knob

[0094] 22: First differential

[0095] 23: Second Motor

[0096] 24: Second rotatable axis

[0097] 25: Second adjustable base

[0098] 26: Second differential

[0099] 27: Scaffold

[0100] 28: Upper support plate

[0101] 29: Lower support plate

[0102] 30: Connecting plate

[0103] 31: Opening

[0104] 32: Axis A

[0105] 33: Axis B

[0106] 34: Axis C

[0107] 35: Axis D

[0108] 36: Locking knob

[0109] 37: First differential shaft

[0110] 38: Second differential shaft

[0111] 39: Axis E

[0112] 40: Axis F DETAILED DESCRIPTION

[0113] Figure 1 A bag making line for producing bags is shown, wherein a fabric material is processed in various stations to form finished block bottom bags or block bottom valve bags. The machine comprises various units, one of which is a cutting unit (not shown) for cutting or separating the fabric material into tubular fabric pieces (2). The tubular fabric piece (2) comprises two bag sections, namely an upper section (2A) and a lower section (2B) superposed on each other, wherein each bag section (2A, 2B) can be composed of multiple layers of different materials. The tubular fabric piece (2) is transferred on a conveyor table (3) by a moving belt (4). On the conveyor table (3), the tubular fabric piece (2) is moved along the conveyor belt (4). Figure 4 , Figure 4A , Figure 4B The plurality of containers are transported one after the other in a conveying direction (5) shown in FIG. 1 , which is transverse to their longitudinal extension axis (6).

[0114] The device (1) of the present invention for forming a bottom opening between bag sections (2A, 2B) at the open end area (2C) of a tubular fabric piece (2) is placed in line with the subsequent units of the bag making production line, so that the tubular fabric pieces (2) when opened by the device (1) can be transferred to the next station on the conveyor table (3) from a state of being laid flat on top of each other to a state of being spaced apart from each other for a perfect square bottom opening.

[0115] Subsequent units of the bag making line are provided to perform these processes. Some of these are:

[0116] ● Fabric roll feeding member, in which a woven or nonwoven fabric roll is loaded to feed the fabric in a forward direction

[0117] ● Fabric edge guiding and unwinding means, in which the fabric is guided on rollers and unwound from the fabric roll

[0118] Fabric preparation components, including:

[0119] - The preparation member optionally consists of a fabric perforating member that removes all air bubbles between the fabric layers for a smooth operation

[0120] - The preparation means may optionally consist of a graduated hole punching means

[0121] - Fabric cleaning components

[0122] ● Inspection and sensing components, which sense the quality of the fabric

[0123] ● Fabric length cutting member, which cuts the fabric into the required bag length

[0124] Conveying members that convey the fabric towards the different bag making areas

[0125] Transverse transfer and guide / feed members that change the direction of the fabric from machine direction to transverse direction to form bags

[0126] ● Defect removal member, which removes defective fabric before forming the bag

[0127] ● Top and bottom edge open components, where both sides of the top and bottom edges of the fabric are opened or folded

[0128] -Vertical positioning of the edge opening member

[0129] - Opening member with rotating mechanism

[0130] Valve patch storage, transport and application components where the patch is applied to the folded fabric before the valve is made

[0131] ● A folding member that folds the edge of the fabric with the valve patch to form a valve

[0132] ● Further conveying means for further conveying the bag with a valve at one end to a further station

[0133] ● Stacking structure for storing bags

[0134] Figure 2The apparatus (1) of the invention is shown, comprising an opening device (7), an upper support plate (28), a lower support plate (29) and a conveyor table (3) with a belt (4). The upper support plate (28) and the lower support plate (29) are identical in structure, but are placed mirror images of each other so that an opening (31) or gap is created to allow the tubular fabric piece (2) to easily travel in the direction of movement of the fabric (5). Furthermore, the upper support plate (28) and the lower support plate (29) are well connected by a connecting plate (30) so that the desired opening (31) is constant throughout the bag making process.

[0135] In one embodiment, the upper support plate (28) and the lower support plate (29) may be made of sheets or plates and strong enough to withstand the loads of other components such as pulleys, rollers, belts and drives (not shown).

[0136] In another embodiment, the connection plate (30) is formed of a metal or non-metal plate or sheet to provide a connection between the upper support plate (28) and the lower support plate (29).

[0137] Furthermore, the connecting plate (30) is rigidly fixed to the base frame (27). The base frame (27) may structurally have a rectangular cross-section or any other suitable shape so that it can bear the load of the device (1) of the present invention.

[0138] The opening device (7) is mounted on a mounting plate (19) and connected to a base frame (27) via a first rotatable shaft (20), which is rotated as required during the bag making process. By means of this adjustment, bags with the following characteristics can be made: Figure 4B Various bags with custom square bottom width ('h') as shown in .

[0139] Figure 3 A perspective view of an opening device (7) is shown, the opening device (7) comprising an upper guide element (7A) having an upper guide surface (7A') rising upwards in the conveying direction (5) and a lower guide element (7B) having a lower guide surface (7B') descending downwards in the conveying direction (5). An endless belt (4) is provided to the guide elements (7A, 7B) so that the endless belt is driven by a first motor (10) to provide a rotational movement to the belt. The guide elements (7A, 7B) are each connected to a suction element (not shown) to ensure that the tubular member (2) is attached to the guide elements (7A, 7B) by suction during its travel through the guide elements (7A, 7B) in a manner known to those skilled in the art.

[0140] In an embodiment, the motor (10) may be selected from the group consisting of an asynchronous motor, a stepper motor or any kind of motor that provides discrete stepping motion to the abutting components.

[0141] The upper guide element (7A) and the lower guide element (7B) are connected via the meshing of the third gear (14) and the second gear (13), respectively, and further, the second gear (13) is meshed with the first gear (11). The motor (10) is connected to the first gear (11) via the shaft (12), so that the power and rotational movement of the motor (10) are transmitted to the corresponding gears (13, 14). This gear meshing system ensures that equal rotational speeds are provided to the belts of the upper guide element (7A) and the lower guide element (7B). The equal rotational speeds of the belts ensure symmetrical opening of the upper section (2A) and the lower section (2B) relative to the movement of the fabric (5).

[0142] The opening device (7) further comprises a pair of unfolding elements (8, 8A), the unfolding elements (8, 8A) being as follows Figure 4 The tubular fabric piece (2) is shown passing between the bag sections (2A, 2B) at the open end region (2C) of the tubular fabric piece (2) to form an opening (2E). There is at least one pair of first unfolding elements, namely a first upper unfolding element (8) and a first lower unfolding element (8A), so that they rotate around axis C (34) and axis E (38).

[0143] Furthermore, a drive mechanism is provided to ensure that the pair of first unfolding elements (8, 8A) are synchronized with the movement of the tubular fabric piece (2) during the end opening process. The drive mechanism comprises a plurality of pulleys and belts so that power is ultimately transmitted from the first motor (10) to the first unfolding elements (8, 8A). A first flanged pulley (13A) is coupled to a second gear (13) driven by the first motor (10). The first flanged pulley (13A) is further connected to a second flanged pulley (16A) via a toothed belt (18). The belt (18) ensures efficient power transmission from one pulley to the other. An idler pulley (17) is present to provide a specified tension to the toothed belt (18) so that any slack in the belt can be overcome by adjusting the idler pulley (17). Such adjustment of the idler pulley (17) to provide tension in the belt (18) is well known to those skilled in the art. A fifth gear (16) is provided and coupled to the second flanged pulley (16A) so as to obtain the same rotation achieved in the second flanged pulley (16A). Furthermore, the fifth gear (16) meshes with the fourth gear (15). Both gears (15, 16) rotate at a speed equal to the speed provided by the first motor (10).

[0144] Furthermore, the first upper deployment element (8) and the first lower deployment element (8A) are each connected to the fourth gear (15) and the fifth gear (16) via a separate first differential (22). The first differential (22) may be of any type so that it converts the movement of the corresponding gears caused by the first motor (10) into a rotational movement of the first deployment element (8, 8A).

[0145] In one embodiment, the meshing of the gears (15, 16) provides the first unfolding element (8, 8A) with the same rotational movement, so that the tubular fabric piece (2) opens equally into the upper section (2A) and the lower section (2B) to form an opening (2E).

[0146] like Figure 2 As shown, the gears (11, 13, 14, 16 and 15) are all mounted on a mounting plate (19) together with the unfolding elements (8, 8A), and the guide elements (7A, 7B) are fixed to a first rotatable shaft (20). The first rotatable shaft (20) is mounted on a first adjustable base (21) that can rotate around an axis A (32). In addition, the first adjustable base (21) includes a right arm (21A), a left arm (21B), a sliding tray (21C) and an adjustment knob (21D).

[0147] In one embodiment, the adjustable base (21) may be made of a metal plate or a non-metal plate so that it can bear the weight of the components mounted thereon.

[0148] In another embodiment, the right arm (21A) and the left arm (21B) can be made of square or angular sections with grooves so that the sliding tray (21C) can slide easily thereon with minimal friction. This sliding of the sliding tray (21C) on the arms (21A, 21B) can be achieved by using any kind of sliding mechanism, such as ball bearings on tracks, gear racks, screw mechanisms, linear motors, etc.

[0149] The opening device (7) further comprises a pair of second unfolding elements (9, 9A) which press the bag sections (2A, 2B) at the open end region (2C) of the tubular fabric piece (2) to form a Figure 4A and Figure 4B The bottom-open upper section (2D) and lower section (2D) are shown. ’ ), thereby forming a bottom opening. There is at least one pair of second unfolding elements, namely a second upper unfolding element (9) and a second lower unfolding element (9A), so that they rotate around the axis D (35) and the axis F (40). The second unfolding elements (9, 9A) are fixed to respective separate second differentials (26), which in turn are connected to the second motor (23) via a single second differential shaft (38). The second differential (26) can be of any type so that it converts the rotational movement of the second motor (23) into the rotational movement of the second unfolding elements (9, 9A). The second motor (23) is mounted on a second rotatable shaft (24).

[0150] In order to adapt to various tubular fabric elements (2) and also to change the Figure 4BThe height 'h' of the bottom opening shown allows the distance between the unfolding elements (8, 8A, 9, 9A) and the support plates (28, 29) to be changed individually. This change can be achieved by adjusting the first rotatable shaft (20) by rotating it around axis A (32), and adjusting the first adjustment base (21) by means of a sliding tray (21C) sliding on the arms (21A, 21B) and locking the sliding tray (21C) by means of a knob (21D). Alternatively, this can be achieved by adjusting the second rotatable shaft (24) by rotating it around axis B (33) on the second adjustable base (25), and locking the position of the second rotatable shaft (24) by means of a locking knob (36), as shown from Figure 3 What I see.

[0151] like Figure 5 As shown, the first upper unfolding element (8) and the first lower unfolding element (8A) are identical in structure. Figure 5 In the arrangement shown, the first upper expansion element (8) and the first lower expansion element (8A) move in a counterclockwise direction around the axis (34, 39), respectively. The first expansion element (8, 8A) includes a first wedge surface (8B), a first wedge extension (8C), and a first wedge end (8D), so that it forms a component. The first wedge surface (8B) is composed of a metal sheet component, or can be machined and bent into an acute angle, so that the first wedge surface (8B) can easily enter the corner (2C) of the tubular member (2) to further open the upper section (2A) and the lower section (2B) of the tubular fabric member (2). In addition, the first wedge extension (8C) connects the first wedge surface (8B) with the first wedge end (8D). A first wedge sleeve (8E) is provided to form a connection with the first differential (22).

[0152] The first wedge-shaped extension (8C) may be formed of the same material as the first wedge-shaped surface (8B), and the first wedge-shaped surface (8B) may be slightly curved so that it does not interfere with other moving elements, such as the second deployment element, during movement.

[0153] Furthermore, the first wedge-shaped end (8D) is a cube on which a counterweight (not shown) can be mounted to provide a precise rotation of the first deployment element (8, 8A) around the axis (34, 39).

[0154] Moreover, the first wedge-shaped sleeve (8E) can be made of a hollow tube or have a tubular cross-section, so that one end is fixed to the first wedge-shaped extension (8C) and the other end is press-fitted to the first differential (22). This fixation can also be achieved by bolting, screwing or welding.

[0155] exist Figure 5As further shown in the figure, the second upper deployment element (9) and the second lower deployment element (9A) are identical in structure and move in the counterclockwise direction around the axes (33) and (40) respectively. The second deployment element (9, 9A) includes a second wedge surface (9B), a second wedge extension (9C), and a second wedge end (9D) so that it forms a single component. The second wedge surface (9B) is formed by a rod so that it is bent at an angle greater than 90° and rounded at the corners to provide a smooth profile so that it reduces friction when the second deployment element (9, 9A) is pressed against the upper section (2A) and the lower section (2B) of the tubular fabric piece (2). In addition, the second wedge extension (9C) connects the second wedge surface (9B) with the second wedge end (9D). A second wedge sleeve (9E) is provided to form a connection with the second differential (26).

[0156] The second wedge-shaped extension (9C) can be made of metal plate, or can be machined and fixed with the second wedge-shaped surface (9B), which can be made into a desired profile to reduce its weight and also be constructed so that it does not interfere with other moving elements during movement.

[0157] Furthermore, the second wedge-shaped end (9D) is a cube on which a counterweight (not shown) can be mounted to provide a precise rotation of the deployment element (9, 9A) around the axis (33, 40).

[0158] In addition, the second wedge sleeve (9E) can be made of a hollow tube or have a tubular cross-section, so that one end is fixed to the second wedge extension (9C) and the other end is press-fitted to the second differential (26). This fixation can be achieved by bolting, screwing or welding.

[0159] Figure 1A as well as Figure 4 , Figure 4A , Figure 4B , Figure 4C and Figure 4D A method for forming a bottom opening at an open end of a tubular fabric piece is shown.

[0160] In particular, Figure 1A The following stages are shown:

[0161] (a) Tubular cut fabric pieces;

[0162] (b) initial opening by a guide element;

[0163] (c) inserting a first expansion element to form an opening;

[0164] (d) pressing the opening form by a second unfolding element;

[0165] (e) A bag having an open end.

[0166] Figure 4 , Figure 4A , Figure 4B , Figure 4C and Figure 4D Some of these stages are shown in detail.

[0167] The method of opening the ends of a tubular fabric member to form a square bottom comprises the following steps:

[0168] a. conveying the tubular fabric member (2) via a belt (4) on a conveyor table (3);

[0169] b. The tubular fabric member (2) enters the opening (31), so that the upper support plate (28) and the lower support plate (29) form barriers for the upper section (2A) and the lower section (2B), respectively, and the tubular fabric member (2) moves

[0170] Move in the direction of motion (5);

[0171] c. The two sections (2A, 2B) are attracted by the upper guide element (7A) and the lower guide element (7B) respectively

[0172] Through the upper guide surface (7A ’ ) and the lower guide surface (7B ’ );

[0173] d. when the tubular fabric member (2) is further advanced by the movement of the guide surfaces (7A', 7B') caused by the first motor (10) and the gear (12, 13, 14) arrangement, a fabric member opening (2E) is generated;

[0174] e. The first upper unfolding element (8) opens the upper section (2A) of the fabric piece (2), and the first lower unfolding element (8) opens the upper section (2A) of the fabric piece (2).

[0175] The element (8A) opens the lower section (2B) of the fabric piece (2);

[0176] f. The tubular fabric member (2) is further advanced, and the second unfolding element (9, 9A) is rotated counterclockwise around the axis D (35) by the second motor (23);

[0177] g. Further, the second upper unfolding element (9) presses the upper section (2D) of the bottom opening, and the second lower unfolding element (9A) presses the lower section (2D') of the bottom opening to open the tubular fabric piece (2) to form a square bottom opening.

[0178] Since prior art machines on both the operating and drive sides are constructed almost identically to be able to work on both ends of a tubular simultaneously, the above description does not discuss each side of the machine in detail.As is apparent from the foregoing description, the present invention has several embodiments.

[0179] Although the above description contains many particularities, these should not be interpreted as limiting the scope of the present invention, but as examples of its preferred embodiments. It must be appreciated that modifications and variations based on the disclosure given above are possible without departing from the spirit and scope of the present invention. Accordingly, the scope of the present invention should not be determined by the illustrated embodiments, but should be determined by the present invention as a whole and the appended claims and their legal equivalents.

Claims

1. An apparatus for opening the ends of a tubular fabric piece (2) to make a square bottom bag, characterized in that: The device (1) comprises: An end opening device (7), the end opening device (7) comprising an upper guide element (7A) and a lower guide element (7B), the upper guide element (7A) having an upper guide surface (7A') rising upward in the conveying direction (5) of the tubular fabric piece (2), and the lower guide element (7B) having a lower guide surface (7B') descending downward in the conveying direction (5); the upper guide element (7A) and the lower guide element (7B) are connected via the meshing of a third gear (14) and a second gear (13), and the second gear (13) is meshed with a first gear (11); a pair of first unfolding elements (8, 8A), the pair of first unfolding elements (8, 8A) being arranged on the first unfolding element (8, 8A) and the second unfolding element ... The open end region (2C) of the tubular fabric piece (2) passes between the bag sections (2A, 2B) to form an opening (2E), and the pair of first unfolding elements (8, 8A) are positioned to rotate around corresponding axes (34, 39) inclined relative to the vertical direction; a pair of second unfolding elements (9, 9A) press the bag sections (2A, 2B) at the open end region (2C) of the tubular fabric piece (2) to form an upper section (2D) and a lower section (2D') of the bottom opening to form a bottom opening, and the pair of second unfolding elements (9, 9A) are positioned to rotate around corresponding axes (35, 40) inclined relative to the vertical direction; an upper support plate (28) and a lower support plate (29), the support plates (28, 29) being placed in mirror image of each other so that an opening (31) or gap is created between them; a connecting plate (30) to which the support plates (28, 29) are fixedly attached, and the connecting plate (30) is rigidly fixed to the base frame (27); A conveying table (3) having an endless belt (4), on which the tubular fabric pieces (2) are conveyed one after the other in the conveying direction (5) transverse to their longitudinal extension axis (6).

2. The apparatus according to claim 1, wherein the upper support plate (28) and the lower support plate (29) are made of sheets or plates, and the connecting plate (30) is composed of a metal or non-metal plate or sheet.

3. Apparatus according to claim 1, wherein the base frame (27) has a rectangular cross section and the connection of the end opening device (7) to the base frame (27) is adjustable.

4. The apparatus according to claim 1, wherein the endless belt (4) is driven by a first motor (10).

5. The apparatus according to claim 1, wherein the guide elements (7A, 7B) are each connected to a suction element which applies a suction force to the tubular fabric piece (2) running through the guide elements (7A, 7B).

6. The device according to claim 4, wherein the first motor (10) is connected to the first gear (11) through a shaft (12), and then transmits power and rotational movement to the corresponding gear (13, 14).

7. The apparatus according to claim 4, wherein a driving mechanism is provided to synchronize the movement of the pair of first unfolding elements (8, 8A) with the movement of the tubular fabric piece (2) in the end opening process of the tubular fabric piece (2) by ultimately transmitting power from the first motor (10) to the first unfolding elements (8, 8A).

8. The apparatus of claim 7, wherein the drive mechanism comprises: A first flanged pulley (13A) is connected to the second gear (13) and is directly driven by the first motor (10). A second flanged pulley (16A) is driven by the first flanged pulley (13A) via a toothed belt (18), The idler wheel (17) provides a specified tension to the toothed belt (18), a fifth gear (16) connected to the second flanged pulley (16A) and meshing with the fourth gear (15), The gears (15, 16) rotate at equal speeds.

9. The device according to claim 8, wherein the pair of first deploying elements (8, 8A) comprises a first upper deploying element (8) and a first lower deploying element (8A), the first upper deploying element (8) and the first lower deploying element (8A) being respectively connected to the fourth gear (15) and the fifth gear (16) via separate first differentials (22).

10. Device according to claim 9, wherein the rotational movements of the first deployment elements (8, 8A) are identical.

11. Device according to claim 9, wherein the distance between the first deployment element (8, 8A) and the second deployment element (9, 9A) and the support plate (28, 29) is variable.

12. The apparatus of claim 9, wherein the first, second, third, fourth and fifth gears (11, 13, 14, 15 and 16) are all mounted on a mounting plate (19) fixed to a first rotatable shaft (20), which in turn is mounted on a first adjustable base (21) directly supported by the base frame (27).

13. The device according to claim 12, wherein the first adjustable base (21) comprises a right arm (21A), a left arm (21B), a sliding tray (21C) capable of sliding on the arms (21A and 21B), and an adjustment knob (21D) for fixing the sliding tray (21C) at a specific position.

14. The apparatus according to claim 13, wherein the right arm (21A) and the left arm (21B) have a square or angular cross-section and are provided with grooves to facilitate the sliding of the sliding tray (21C), and the sliding tray (21C) can slide thereon using a sliding mechanism.

15. The apparatus according to claim 14, wherein the sliding mechanism is any one selected from a ball bearing on a track, a rack and pinion pair, a lead screw mechanism, and a linear motor.

16. Apparatus according to any one of claims 9 to 15, wherein the second deployment elements (9, 9A) are fixed to respective individual second differentials (26), which in turn are connected to a second motor (23) via a single second differential shaft (38), and wherein the second motor (23) is mounted on a second rotatable shaft (24) fixed to a second adjustable base (25).

17. Apparatus according to claim 16, wherein the second rotatable shaft (24) is locked in position by a locking knob (36).

18. The apparatus of claim 16, wherein each of the first spreading elements (8, 8A) comprises a first wedge-shaped surface (8B) and a first wedge-shaped end (8D), a first wedge-shaped extension (8C) integrally connecting the first wedge-shaped surface (8B) and the first wedge-shaped end (8D), and a first wedge-shaped sleeve (8E) connecting the first spreading element (8, 8A) to the corresponding first differential (22).

19. The device according to claim 18, wherein each of the second spreading elements (9, 9A) comprises a second wedge surface (9B) and a second wedge end (9D), a second wedge extension (9C) integrally connecting the second wedge surface (9B) and the second wedge end (9D), and a second wedge sleeve (9E) connecting the second spreading element (9, 9A) to the corresponding second differential (26).

20. The apparatus according to claim 19, wherein the second wedge surface (9B) is composed of a linear member having a smooth surface and is bent to form an included angle greater than 90°.

21. The device according to claim 18, wherein the first wedge surface (8B) is curved to have a convex shape that does not interfere with other moving elements.

22. The device according to claim 19, wherein a counterweight is mounted on the first wedge-shaped end (8D) and / or on the second wedge-shaped end (9D).

23. The device according to claim 16, wherein separate motors drive the first deployment element (8, 8A) and the second deployment element (9, 9A).

24. A method for opening the ends of a tubular fabric piece to form a square bottom using the apparatus as claimed in any one of claims 16 to 23, the method comprising the steps of: a. conveying the tubular fabric member (2) via a belt (4) on the conveyor table (3); b. passing the tubular fabric member (2) through the opening (31) so that the upper support plate (28) and the lower support plate (29) form barriers for the upper section (2A) and the lower section (2B), respectively, and the tubular fabric member moves in the conveying direction (5); c. using the upper guide element (7A) and the lower guide element (7B) to attract the two sections (2A, 2B) to pass through the upper guide surface (7A ’ ) and the lower guide surface (7B ’ ); d. passing the pair of first unfolding elements (8, 8A) between the bag sections (2A, 2B) at the open end region (2C) of the tubular fabric piece (2) to form an opening (2E), and then further advancing the tubular fabric piece (2) by moving the guide surfaces (7A', 7B') driven by the first motor (10) and the gears (11, 13 and 14); e. using the first upper unfolding element (8) to open the upper section (2A) of the tubular fabric member (2), and using the first lower unfolding element (8A) to simultaneously open the lower section (2B) of the tubular fabric member (2); f. Further advancing the tubular fabric piece (2), and using the second motor (23) to rotate the second upper unfolding element (9) of the pair of second unfolding elements (9, 9A) around the axis (35) to press the upper section (2D) of the bottom opening, and at the same time rotating the second lower unfolding element (9A) of the pair of second unfolding elements (9, 9A) to press the lower section (2D') of the bottom opening, thereby opening the tubular fabric piece (2) to form a square bottom opening.

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