CN115697686B

CN115697686B - Apparatus and method for opening the ends of a tubular fabric piece to make a block bottom bag

Info

Publication number: CN115697686B
Application number: CN202180041406.2A
Authority: CN
Inventors: 高雷夫·罗希亚
Original assignee: Lohia Corp Ltd
Current assignee: Lohia Corp Ltd
Priority date: 2020-05-11
Filing date: 2021-05-08
Publication date: 2025-03-14
Anticipated expiration: 2041-05-08
Also published as: TWI766683B; EP4149748A4; TW202210285A; CN115697686A; WO2021229395A1; EP4149748A1

Abstract

The invention relates to a device and a method for opening the ends of a tubular piece of fabric (2) to produce a square bottom or square bottom. The device comprises an end opening means (7), two rotary differentials (22, 26) positioned at an angle to the plane of the fabric piece (2). Each differential (22, 26) has an axle on which a pair of spreading elements (8, 9) formed by shaping the lever into a curved shape are mounted. The deployment elements (8, 8A, 9A) form a three-dimensional virtual shape when rotated. The layers of the bag body at its open end are unfolded by means of guide elements (7A, 7B) of the opening device (7) near one corner to form an opening at the bottom, into which one of the unfolded elements is inserted. The continuous rotary movement of the drive ensures that both spreading elements enter the opening and progressively and continuously spread the layers of fabric piece (2) at the open end towards each other to form a square bottom.

Description

Apparatus and method for opening ends of tubular fabric articles to make square bottom bags

Technical Field

The present invention relates to an apparatus and method for opening the ends of tubular fabric articles to make square or square bases.

Background

The production of square bottom bags generally involves providing a tubular fabric material obtained by producing a tubular fabric material or by joining the longitudinal edges of a flat fabric material to obtain a tubular configuration, cutting the tubular material to obtain a bag of suitable length, and forming the bag bottom by appropriately folding and closing one end of the bag. Bags with rectangular bottoms produced in this manner are commonly referred to by those skilled in the art as box bags.

To form the bottom of such a box-type bag, the ends of one of the two bag walls that lie one above the other in the flat bag are folded along a folding line that extends transversely to the longitudinal axis of the bag, so that the ends of the bag adopt a hexagonal folded configuration with two parallel seams that are opposite one another and two pairs of parallel folded edges that are opposite one another. By folding the two seams towards each other and securing the folded leaflets comprising the seams to each other or to the covering sheet, the bag body is provided with a bottom portion that adopts a rectangular configuration when the completed bag is folded apart. It is also possible to apply a valve panel before the seams are folded towards each other, which panel adopts a tubular configuration when the ends of the bag are folded into their final shape.

Means for opening the ends of the tube to open the bottom square are known and are part of a bag/twine making apparatus. Here, the devices described hereinafter, in particular those comprising woven fabrics made of stretched plastic tapes, are processed on a bag/sack making device which can handle tubes made of any material, preferably tubes made of plastic.

An apparatus for producing sacks has been disclosed in patent application DE 19502251A1, which describes a bottom opening device in which a piston rod carrying a slider member for opening a bottom pane is provided. The slider moves to the raised position while extending into the plane of the tube so as to fold the upper wall of the tube along its own fold line. Subsequently, the slider is lowered in the extended position to press the wall, and then retracted again. In order for the slider to function properly, the hose piece to be opened needs to be in a stationary state. Therefore, the supply of the pipe must be stopped first. After the bottom has been opened, the tube has to be accelerated again to be transported to the next processing station.

However, the bottom opening device disclosed in said DE 19502251A1 proves to be disadvantageous because it is too slow. Furthermore, such devices are prone to wear.

Another german application No. de912045 discloses a device for a cross bottom bag machine, in which a sickle with sickle-shaped bottom laying bars or drives is used, which drive consists of a machine drive and two driven gears. In the sense of said patent application, the bottom laying rod/sickle, which may be referred to as a member for opening, is at least partially movable in the conveying direction and in the extending direction of the hose piece. The gear and the machine drive may be considered as the first moving member. However, the sickle-shaped bottom laying sticks/sickles only contact the hose pieces at certain points, so that the hose pieces, especially in the case where they comprise thin plastic strips, often cannot be opened safely.

Furthermore, in the prior art, a bottom opening station is used with a rotary spreading tool having an upper and a lower part that move apart during the orbital movement of the mechanism. However, such multipart deployment tools are disadvantageous because of their complex structure and susceptibility to error. In addition, such deployment tools require a large number of settings.

A further example of a bag opening device is disclosed in EP3148788A1 (' 788), in which an apparatus and a method for forming a bottom opening between bag sections are shown, in which groups of wedge-shaped elements have a complex geometry. It is further disclosed in the' 788 patent that these wedge members are driven by a common driver. The main disadvantage of this invention is that no wedge elements are provided to accommodate a wide range of bags. Another disadvantage of the' 788 invention is that the width of the bag bottom cannot be changed during machine operation. A further disadvantage that may be stated with respect to the invention (' 788) is that when all wedge elements are driven by a single drive, it is not possible to correct errors if errors are caused by movement of the wedge elements during the bag making process.

Other devices for opening the bottom of a 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 quick adjustment of the bottom open end for accommodating different sized openings and tubular fabric widths. Furthermore, such devices involve very complex processes and movements of the various components, which reduce the overall efficiency and accuracy of the system.

Accordingly, there is a need for an opening device that can be operated at high speed, at low maintenance costs, and that is easy to set for different material specifications.

The present invention provides a device for bottom opening by means of which the drawbacks of the prior art are overcome and which is robust, reliable, at the same time requires little maintenance and allows production speeds far higher than those of the systems known in the prior art.

Disclosure of Invention

The invention aims to:

It is an object of the present invention to provide a bottom opening device that can be operated at high speed and with precision.

It is a further object of the present invention to provide an apparatus that is easy to set up to process different types of tubular textile materials.

It is a further object of the present invention to provide an apparatus and method for quick adjustment to accommodate different sized openings and tubular fabric widths.

It is a further object of the invention to provide a device that is minimally worn and easy to maintain.

It is a still further object of the present invention to provide a device for producing a bottom opening with high accuracy and reliability in continuous operation, wherein the device is simple in construction.

Summary of the invention:

according to the present invention, there is provided an apparatus for opening the ends of a bag. In an automated bag-making line, several processes are performed to convert tubular or flat fabric into bags. Stations are provided to perform these processes. Some of these are:

● A fabric roll feeding member in which a woven or nonwoven fabric roll is loaded to feed fabric in a forward direction

● Fabric edge guiding and releasing member wherein fabric is guided on rollers and released from fabric rolls

● A fabric preparation member, wherein:

The preparation member is optionally composed of a fabric perforation member which removes all air bubbles between the fabric layers for smooth operation

The preparation member is optionally composed of an indexing hole punching member

Fabric cleaning element

● Inspection and sensing member that senses the mass of fabric

A fabric length cutting member that cuts the fabric into the desired bag length

A conveying member for conveying the fabric toward different bag making areas

A transverse transfer and guide/feed member which changes the direction of the fabric from longitudinal to transverse to form a pocket

Defect-eliminating member which eliminates defective fabric before forming bag

A top edge and bottom edge opening member wherein both sides of the top and bottom edges of the fabric are opened or folded

-A vertically positioned edge opening member

Opening member with rotation mechanism

● Valve patch storage, delivery and adhesive means wherein the patch is applied to a folded fabric prior to making the valve

Folding member which folds the edge of the fabric with the valve patch to form a valve

A further conveying member which conveys further bags with valves at one end to a further station

● Stacking member for storage bags

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

During transport on the transport device, the layers of the bag body at the open end of the tubular bag body are unfolded by means of a guiding element near one corner to form an initial opening at the bottom.

To open the pouch, one of the pair of raised profile shaped deployment elements is inserted into the initial opening. The continuous rotary movement of the drive ensures that the two deployment elements enter the initial opening and progressively and continuously deploy the layers of the bag body at the open end from each other to form a square bottom. Further, another pair of deployment elements driven by a separate driver presses the bag ends to form a hexagonal shape.

Drawings

Figure 1 shows a perspective view of a bag making line.

Fig. 1A shows a flow chart of a process of opening a bag end:

(a) Tubular cutting the fabric article;

(b) Initially opened by the guide element;

(c) Inserting a first deployment element to form an opening;

(d) Pressing the open form by the second deployment element;

(e) A pouch having an open end.

Fig. 2 shows the apparatus of the present invention.

Fig. 3 shows a perspective view of the opening device.

Fig. 4, 4A, 4B show different stages of bag opening including an initial opening stage.

Fig. 4C, 4D show an enlarged view of the bag being opened by the deployment element.

Figure 5 illustrates the deployment element and its movement.

Parts list:

1 apparatus according to the invention

2 Tubular textile element

2A upper section

2B lower section

2C open end region

2D upper section of bottom opening

2D': lower section of bottom opening 2E: textile element opening

3 Transfer table

4 Band

5 Direction of movement of the Fabric

6 Longitudinal extension axis

7 Opening device

7A upper guide element

7A': upper guide surface

7B lower guide element

7B': lower guide surface 8: first upper spreading element

8A first lower deployment element

8B first wedge surface

8C first wedge-shaped extension

8D first wedge-shaped end

8E first wedge sleeve 9 second upper deployment element

9A second lower deployment element

9B second wedge surface

9C second wedge-shaped extension

9D second wedge-shaped end

9E second wedge sleeve 10 first motor

11 First gear

12 Shaft 13 second gear

13A first flanged pulley 14 third gear

15, Fourth gear 16, fifth gear

16A second flanged pulley 17 idler pulley

18 Toothed belt

19 Mounting plate

20 First rotatable shaft

21 First adjustable base

21A right arm

21B left arm

21C sliding tray

21D adjusting knob

22 First differential mechanism

23 Second motor

24 Second rotatable shaft

25 Second adjustable base

26 Second differential mechanism

27 Base frame

28 Upper support plate

29 Lower support plate

30 Connecting plate

31 Opening of

32 Axis A

33 Axis B

34 Axis C

35 Axis D

36 Locking knob

37 First differential shaft

38 Second differential shaft

39 Axis E

40 Axis F

Detailed Description

Fig. 1 shows a bag making line for producing bags, wherein a fabric material is processed in various stations to form finished square bottom bags or square bottom valve bags. The machine comprises units, one of which is a cutting unit (not shown) for cutting or separating the textile material into tubular pieces of textile (2). The tubular fabric piece (2) comprises two bag sections, an upper section (2A) and a lower section (2B) which are stacked on top of each other, wherein each bag section (2A, 2B) may be composed of a plurality of layers of different materials. The tubular piece of fabric (2) is transferred on the transfer table (3) by means of a moving belt (4). On the transfer table (3), the tubular fabric pieces (2) are transferred in succession in a conveying direction (5) transverse to their longitudinal extension axis (6) shown in fig. 4, 4A, 4B.

The inventive device (1) for forming a bottom opening between bag sections (2A, 2B) at an open end region (2C) of a tubular fabric piece (2) is placed in line with a subsequent unit of a bag making line, so that the tubular fabric piece (2) can be transferred on a transfer table (3) from a state lying one on the other to a state spaced apart from each other for perfect square bottom opening when opened by the device (1).

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

● A fabric preparation member, wherein:

Fabric cleaning element

● Inspection and sensing member that senses the mass of fabric

● A fabric length cutting member that cuts the fabric into a desired bag length

A conveying member for conveying the fabric toward different bag making areas

● Defect eliminating member for eliminating defective fabric before forming bag

● A top edge and bottom edge opening member wherein both sides of the top and bottom edges of the fabric are opened or folded

-A vertically positioned edge opening member

Opening member with rotation mechanism

Valve patch storage, transfer and adhesive means, wherein the patch is applied to a folded fabric prior to making the valve

● Folding member which folds the edge of the fabric with the valve patch to form a valve

● A further conveying member for further conveying bags having a valve at one end to a further station

● Stacking member for storage bags

Fig. 2 shows an apparatus (1) of the invention comprising an opening device (7), an upper support plate (28), a lower support plate (29) and a transfer 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 piece of fabric (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) such that the required opening (31) is constant throughout the bag making process.

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

In another embodiment, the connection plate (30) is constructed 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).

Furthermore, the connection plate (30) is rigidly fixed to the base frame (27). The base frame (27) may be of rectangular cross-section or any other suitable shape in its construction so that it can withstand the load of the device (1) of the invention.

The opening device (7) is mounted on a mounting plate (19) and is connected to a base frame (27) via a first rotatable shaft (20), the first rotatable shaft (20) being rotated as required in the bag making process. With this adjustment, various bags having a custom square bottom width ('h') as shown in fig. 4B can be made.

Fig. 3 shows a perspective view of the opening device (7), the 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 upwards in the conveying direction (5), the lower guide element (7B) having a lower guide surface (7B') falling downwards in the conveying direction (5). An endless belt (4) is provided to the guide elements (7A, 7B) such that the endless belt is driven by a first motor (10) to provide a rotational movement to the belt. The guiding elements (7A, 7B) are each connected to a suction element (not shown) to ensure that the tubular member (2) is attached to the guiding elements (7A, 7B) by suction forces during its travel through the guiding elements (7A, 7B) in a manner known to the person skilled in the art.

In an embodiment, the motor (10) may be selected from the group of asynchronous motors, stepper motors, or any kind of motor that provides discrete stepping motion to the adjoining components.

The upper guide element (7A) and the lower guide element (7B) are connected via engagement of a third gear (14) and a second gear (13), respectively, and further the second gear (13) is engaged with the first gear (11). The motor (10) is connected to the first gear (11) by a shaft (12) such that the power and rotational movement of the motor (10) is transferred to the respective gears (13, 14). This gear engagement system ensures that equal rotational speeds are provided for the belts of the upper (7A) and lower (7B) guide elements. The equal rotation speed of the belt ensures a symmetrical opening of the upper section (2A) and of the lower section (2B) with respect to the movement of the fabric (5).

The opening device (7) further comprises a pair of developing elements (8, 8A), the developing elements (8, 8A) passing between the bag sections (2A, 2B) at the open end region (2C) of the tubular piece of fabric (2) as shown in fig. 4, thereby forming an opening (2E). There is at least one pair of first spreading elements, namely a first upper spreading element (8) and a first lower spreading element (8A), such that they rotate about an axis C (34) and an axis E (38).

Furthermore, a drive mechanism is provided for ensuring that the pair of first unwinding members (8, 8A) is synchronised with the movement of the tubular piece of fabric (2) during the end opening process. The drive mechanism comprises several pulleys and belts so that power is finally transmitted from the first motor (10) to the first deployment element (8, 8A). The first flanged pulley (13A) is coupled with 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 (17) is present to provide a prescribed tension to the toothed belt (18) so that any slack in the belt can be overcome by adjusting the idler (17). Such adjustment of the idler (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 with the second flanged pulley (16A) so as to obtain the same rotation achieved in the second flanged pulley (16A). The fifth gear (16) is in mesh with the fourth gear (15). The two gears (15, 16) rotate at a speed equal to the speed provided by the first motor (10).

Furthermore, the first upper (8) and lower (8A) spreading elements are each connected to a fourth (15) and fifth (16) gear via a separate first differential (22). The first differential (22) may be of any type such that it converts the movement of the respective gear caused by the first motor (10) into a rotational movement of the first unwinding member (8, 8A).

In one embodiment, the engagement of the gears (15, 16) provides the same rotational movement for the first deployment element (8, 8A) such that the tubular fabric piece (2) opens identically into the upper section (2A) and the lower section (2B) to form the opening (2E).

As shown in fig. 2, the gears (11, 13, 14, 16 and 15) are all mounted on the mounting plate (19) together with the deployment element (8, 8A), and the guide element (7A, 7B) is fixed to the first rotatable shaft (20). The first rotatable shaft (20) is mounted on a first adjustable base (21) rotatable about 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).

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

In another embodiment, the right arm (21A) and the left arm (21B) may be made of square or angled cross sections with grooves so that the sliding tray (21C) can easily slide 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 rails, rack-and-pinion, screw mechanisms, linear motors, etc.

The opening device (7) further comprises a pair of second unfolding elements (9, 9A), which pair of second unfolding elements (9, 9A) press the bag sections (2A, 2B) at the open end area (2C) of the tubular piece of fabric (2) to form an upper section (2D) and a lower section (2D ^') of the bottom opening as shown in fig. 4A and 4B, thereby forming the bottom opening. There is at least one pair of second spreading elements, namely a second upper spreading element (9) and a second lower spreading element (9A), such that they rotate about an axis D (35) and an axis F (40). The second unwinding elements (9, 9A) are fixed to respective individual second differentials (26), the second differentials (26) in turn being connected to the second motor (23) via a single second differential shaft (38). The second differential (26) may be of any type such that it converts the rotational movement of the second motor (23) into a rotational movement of the second deployment element (9, 9A). A second motor (23) is mounted on a second rotatable shaft (24).

To accommodate various tubular fabric pieces (2) and also to vary the height 'h' of the bottom opening as shown in fig. 4B, the distance between the spreading element (8, 8A, 9A) and the support plate (28, 29) can be individually varied. This change can be accomplished by rotating the first rotatable shaft (20) about the axis a (32) to adjust the first rotatable shaft (20) and by adjusting the first adjustment base (21) via a sliding tray (21C) sliding on the arms (21A, 21B) and locking the sliding tray (21C) by a knob (21D). Alternatively, this may be achieved by rotating the second rotatable shaft (24) about the axis B (33) on the second adjustable base (25) to adjust the second rotatable shaft (24) and locking the position of the second rotatable shaft (24) by a locking knob (36), as seen in fig. 3.

As shown in fig. 5, the first upper (8) and lower (8A) deployment elements are identical in structure, and in the arrangement shown in fig. 5, the first upper (8) and lower (8A) deployment elements are moved in a counter-clockwise direction about axes (34, 39), respectively. The first deployment element (8, 8A) comprises a first wedge surface (8B), a first wedge extension (8C), a first wedge end (8D) such that it forms one part. The first wedge surface (8B) is formed of sheet metal parts or may be machined and bent at an acute angle such that the first wedge surface (8B) can easily enter the corner (2C) of the tubular piece (2) to further open the upper section (2A) and the lower section (2B) of the tubular piece (2). Furthermore, 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 a first differential (22).

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

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

Moreover, the first wedge sleeve (8E) may be made of a hollow tube or have a tubular cross section such that one end is fixed to the first wedge extension (8C) and the other end is press-fitted to the first differential (22). Such fixing may also be achieved by bolting, screwing or welding.

As further shown in fig. 5, the second upper deployment element (9) and the second lower deployment element (9A) are identical in structure, moving in a counter-clockwise direction about axes (33) and (40), respectively. The second deployment element (9, 9A) comprises a second wedge surface (9B), a second wedge extension (9C), a second wedge end (9D) such that it forms one part. The second wedge surface (9B) is constituted by a bar such that it is bent at an angle greater than 90 ° and rounded at the corners to provide a smooth profile such that it reduces friction when the second spreading element (9, 9A) is pressed against the upper section (2A) and the lower section (2B) of the tubular piece of fabric (2). Furthermore, a 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 a second differential (26).

The second wedge extension (9C) may be composed of sheet metal or may be machined and fixed with the second wedge surface (9B), the second wedge surface (9B) may be profiled as desired to reduce its weight and also be configured such that it does not interfere with other moving elements during movement.

Moreover, 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) about the axis (33, 40).

Furthermore, the second wedge sleeve (9E) may be made of a hollow tube or have a tubular cross section such that one end is fixed to the second wedge extension (9C) and the other end is press-fitted to the second differential (26). Such fixing may be achieved by bolting, screwing or welding.

Fig. 1A and fig. 4, 4A, 4B, 4C and 4D illustrate a method for forming a bottom opening at an open end of a tubular piece of fabric.

In particular, fig. 1A shows the following phases:

(a) Tubular cutting the fabric article;

(b) Initially opened by the guide element;

(c) Inserting a first deployment element to form an opening;

(d) Pressing the open form by the second deployment element;

(e) A pouch having an open end.

Fig. 4, 4A, 4B, 4C, and 4D show some of these stages in detail.

The method of opening the ends of a tubular fabric article to form a square bottom comprises the steps of:

a. Conveying the tubular fabric piece (2) on a conveyor table (3) via a belt (4);

b. The tubular piece of fabric (2) enters the opening (31) such that the upper support plate (28) and the lower support plate (29) form a barrier for the upper section (2A) and the lower section (2B), respectively, and the tubular piece of fabric (2) is moving

Moving in a moving direction (5);

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

Through the upper guide surface (7 a ^') and the lower guide surface (7B ^');

d. When the tubular piece of fabric (2) is further advanced by the movement of the guide surfaces (7A ', 7B') caused by the arrangement of the first motor (10) and the gears (12, 13, 14), a piece of fabric opening (2E) is created;

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

The element (8A) opens the lower section (2B) of the piece (2);

f. The tubular piece of fabric (2) is further advanced and the second unwinding element (9, 9A) is rotated anticlockwise about the axis D (35) by a second motor (23);

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 piece of fabric (2) to form a square bottom opening.

Since the prior art machines of the operating side and the driving side are constructed almost identically so as to be able to work simultaneously on both ends of the tubular element, the above description does not discuss in detail the various sides of the machine. As is apparent from the foregoing description, the present invention has several embodiments.

While the above description contains many specificities, these should not be construed as limiting the scope of the invention but as exemplifications of preferred embodiments thereof. 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 invention. Accordingly, the scope of the invention should be determined not by the embodiments illustrated, but by the appended claims and their legal equivalents.

Claims

1. A device 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), the 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 surface (8B) and a first wedge end (8D), a first wedge extension (8C) integrally connecting the first wedge surface (8B) and the first wedge end (8D), and a first wedge 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) 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 simultaneously 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.