Bottom-forming station and method for forming a fold-over bottom on a piece of fabric tube

Abstract

The invention relates to a bottom forming station (16) and to a method for forming a fold-over bottom, preferably a pinch bottom, on a piece of fabric tube (11) comprising a strip fabric made of plastic strips, preferably strips substantially made of a partially crystalline thermoplastic, preferably polyolefin, for example polypropylene (PP) or polyethylene (PE), or polyester, for example polyethylene terephthalate (PET) or polylactide (PLA), comprising: a conveying device (20) for conveying the piece of fabric tube (11) in a conveying direction (21) along a conveying plane; and a fold-over device (22) for folding over an end region of the piece of fabric tube (11) onto a fabric tube wall (11A) of the piece of fabric tube (11), the fold-over device (22) having a hold-down unit (26) with at least two hold-down parts (27), which follow one another in the conveying direction (21) and which are designed to move the end region of the piece of fabric tube (11) increasingly towards the fabric tube wall (11A) in the conveying direction (21), a respective recess (28) being formed between each pair of hold-down parts (27) following one another in the conveying direction (21) in order to receive a build-up of material at the end region of the piece of fabric tube (11).

Description

[0001] SOIL FORMATION STATION AND METHOD FOR THE FORMATION OF A FOLDING SOIL ON A PIECE OF FABRIC HOSE

[0002] The invention relates to a floor formation station for forming a folding floor, preferably a pinch floor, on a fabric tube section with a tape fabric made of plastic tapes, preferably essentially of semi-crystalline thermoplastic, preferably of polyolefin, for example polypropylene.

[0003] (PP) or polyethylene (PE), or made of polyester, for example polyethylene terephthalate (PET) or polylactide (PLA), comprising: a conveying device for conveying the fabric hose piece in a conveying direction along a conveying plane, a folding device for folding an end area of ​​the fabric hose piece onto a fabric hose wall of the fabric hose piece.

[0004] Furthermore, the invention relates to a method for forming a fold-over bottom, preferably a pinch bottom, on a fabric tube piece with a tape fabric made of plastic tapes, preferably essentially made of semi-crystalline thermoplastic, preferably made of polyolefin, for example polypropylene (PP) or polyethylene (PE), or of polyester, for example polyethylene terephthalate (PET) or polylactide (PLA).

[0005] Finally, the invention relates to a device and a method for manufacturing woven bags, preferably fold-bottom woven bags, preferably pinch-bottom woven bags.

[0006] As described in EP 2 599 617 Bl, woven pinch bags are known in which a printed film is applied to stretched polyolefin fabric. These woven pinch bags offer the necessary stability for the consumer sector, in addition to an attractive appearance, for packaging products such as pet food. To create the pinch bottom, one end of the tubular section is folded over by 180° and secured to the bag wall. Due to the restoring forces of the resilient woven material, the formation of the pinch bottom presents particular challenges. In the prior art of EP 2 599 617 Bl, the folding is accomplished by a double-walled guide element. The end of the tubular section slides from a conveyor table between the walls of the guide element. In doing so, the end of the tubular section is folded over onto the front wall.During this process, the bag material in the folding area is heated by hot air, which is introduced through a hot air nozzle, thus warming the plastic material to be joined. The hose section is then pressed between press rollers, with the pinch bottom being formed by welding the molten plastic material.

[0007] A disadvantage of the current state of the art, however, is that the end section is not always folded smoothly, which makes the subsequent connection more difficult or worse. Furthermore, compression can occur when threading the end of the hose section between the guide elements.

[0008] In contrast, the object of the present invention is to provide a bottom-forming station, a method for forming a folded bottom, and a device for manufacturing woven bags, with which the disadvantages of the prior art are at least partially alleviated or eliminated. The invention preferably aims to achieve a particularly smooth folding of the end region in order to optimally prepare the subsequent connection with the adjacent woven tube wall.

[0009] This problem is solved by a soil formation station according to claim 1, a method according to claim 13, and a device according to claim 14. Preferred embodiments are specified in the dependent claims.

[0010] According to the invention, the folding device comprises a hold-down unit with at least two hold-down elements arranged successively in the conveying direction, which are designed to increasingly bring the end region of the fabric hose section closer to the fabric hose wall in the conveying direction. Between each set of hold-down elements in the conveying direction, a recess is provided for receiving any material build-up from the end region of the fabric hose section.

[0011] In the prior art, the end section is continuously folded over onto the adjacent bag wall via a continuous, double-walled guide element. The invention is based on the finding that constantly guiding the entire end section from the outside when positioning it against the bag wall does not yield optimal results. In contrast, the holding unit according to the invention has several holding elements, with a recess, preferably exactly one, provided between each pair of successive holding elements, i.e., adjacent in the conveying direction. The holding elements progressively guide the end section of the fabric hose closer to the adjacent section of the fabric hose in the conveying direction. The holding elements thereby hold the end section of the fabric hose from the outside, i.e.,The end section of the fabric tube is forced downwards from the side facing away from the adjacent area of ​​the fabric tube section towards that area. According to the invention, during folding in the hold-down unit, the end section is partially released by at least one recess, so that the section of the end section located in the recess can bulge outwards to form a material build-up. Such a material build-up can then be smoothed out, i.e., at least partially, preferably substantially completely, by the hold-down element following in the conveying direction. The hold-down elements are arranged closer to the conveying plane from one hold-down element to the next in the conveying direction, on which the fabric tube section is conveyed by the conveying device.Thus, the hold-down elements are increasingly inclined to the normal onto the, preferably horizontal, conveying plane in the conveying direction. This increases the degree of folding in the conveying direction from hold-down element to hold-down element. With the last hold-down element viewed in the conveying direction, the end region is preferably folded substantially completely onto the connecting surface of the adjacent area of ​​the fabric hose section, i.e., onto the fabric hose wall facing the fabric hose section, so that the end region is arranged substantially parallel to a connecting section of the fabric hose wall facing the end region. Advantageously, with the embodiment according to the invention, the end region can be folded so precisely that the connection of the end region with the opposite connecting section of the fabric hose wall is optimally prepared.The invention is based on the surprising finding that the folding result can be improved if material build-up is not suppressed by complete external guidance during folding, but rather the material build-up can initially form in the recess, but is smoothed out by the hold-down part immediately following the recess.

[0012] In a preferred embodiment, the hold-down elements are arranged immovably relative to each other. The progressive clamping of the end region of the fabric hose section is achieved in this embodiment by the different arrangement of the hold-down elements with respect to the conveying plane. Stationary hold-down elements are preferably provided.

[0013] Depending on the design, the first hold-down element, viewed in the conveying direction, can be configured to hold the end section of the fabric hose in a flat state, aligned along the conveying plane. However, it is particularly preferred if the first hold-down element, viewed in the conveying direction, is configured to hold the end section of the fabric hose in a state angled from the conveying plane, preferably by substantially 90°. As the material passes the hold-down elements, the end section is increasingly forced towards the fabric hose wall by the hold-down elements.

[0014] In a preferred embodiment, each of the hold-down elements has a hold-down edge along which the end region of the fabric hose section is guided. Preferably, each recess extends between the hold-down edges of two hold-down elements that follow one another in the conveying direction.

[0015] The hold-down edges preferably run in planes that extend essentially parallel to the fold line between the end region and the adjacent region of the fabric hose section. These planes are preferably positioned at acute angles to the conveying plane. Preferably, the acute angles decrease from hold-down element to hold-down element in the conveying direction, i.e., the angle of a subsequent hold-down element is smaller than the angle of the preceding hold-down element.

[0016] In a preferred embodiment, the holding unit has at least three, preferably at least four, preferably at least five, for example at least six holding elements, which are spaced apart from each other in pairs by a recess. This allows the end region of the fabric tube section to bulge out "freely" several times in the space of the respective recesses during its successive movement or guidance through the holding elements towards its adjacent region – distributed over the length of the end region.

[0017] In a first preferred embodiment, the hold-down unit has exactly six hold-down elements, which are spaced apart from each other in pairs by a recess. This embodiment preferably achieves a folding angle of essentially 85°. In a further preferred embodiment, the hold-down unit has exactly seven hold-down elements, which are spaced apart from each other in pairs by a recess. This embodiment preferably achieves a folding angle of essentially 90°.

[0018] In a preferred embodiment, the acute angles between the planes running parallel to the fold line and the conveying plane decrease by 5° to 30°, preferably by 10° to 25°, for example by 14° to 21°, from hold-down to hold-down in the conveying direction. Alternatively, the acute angles between the planes running parallel to the fold line and the conveying plane decrease by 12° to 21° from hold-down to hold-down in the conveying direction.

[0019] In a preferred embodiment, the retaining edge of the last, preferably the sixth, retaining element (as viewed in the conveying direction) is arranged substantially parallel to the conveying plane, so that the end section is folded over onto the fabric hose wall after the last retaining element. Thus, after passing the last retaining element, the end section of the fabric hose preferably extends substantially parallel to the conveying plane along which the fabric hose section is conveyed. Preferably, a gap is formed between the inside of the folded end section and the outside of the opposite connecting section of the fabric hose wall. This gap is preferably used for introducing heat, preferably via a hot gas nozzle, or alternatively for introducing an adhesive or bonding agent.

[0020] For the purposes of this disclosure, the location and direction references, such as "above", "below", "horizontal", "vertical", refer to an intended state of use of the soil formation station or of a device containing this soil formation station for the production of woven bags.

[0021] In a preferred embodiment, the respective hold-down edge is arranged such that the end region of the fabric hose section first contacts the end of the hold-down edge facing the fold line. Thus, the section of the end region adjacent to the fold line comes into contact with the respective hold-down edge first, before the sections of the end region towards its free end are gradually contacted by the hold-down edge. For this purpose, the end of the hold-down edge facing the fold line can be positioned in the conveying direction in front of the end of the hold-down edge facing away from the fold line. Advantageously, this achieves a particularly precise folding action. In a preferred embodiment, the hold-down edges are inclined forward with respect to the conveying direction.

[0022] In a preferred embodiment, the end of a hold-down edge facing away from the fold line is arranged essentially at the same longitudinal position (i.e., position in the conveying direction) as the end of the hold-down edge facing the fold line following in the conveying direction.

[0023] In a preferred embodiment, the hold-down edges are curved. Preferably, the slope of each hold-down edge towards the conveying plane increases from the end facing the fold line to the end of the hold-down edge furthest from the fold line. In a preferred embodiment, the depth, i.e., the extent perpendicular to the conveying direction and parallel to the conveying plane, of at least one hold-down part increases, preferably continuously, from an end facing the conveying plane to an end facing away from the conveying plane.

[0024] In a preferred embodiment, at least one of the hold-down elements is wedge-shaped. The wedge-shaped hold-down element preferably tapers from an end facing the conveying plane, preferably the lower end, to an end facing away from the conveying plane, preferably the upper end. In this embodiment, it is advantageous if the hold-down edge is formed on a front wedge surface facing the end region of the fabric hose section.

[0025] To facilitate the transfer of the end area, it is advantageous if the hold-down part runs from the end facing the conveying level, preferably the lower end, to the end facing away from the conveying level, preferably the upper end.

[0026] To achieve a stable, easy-to-manufacture design, it is advantageous if at least two of the hold-down parts are connected to each other via a common back panel. Preferably, the hold-down parts and the common back panel are formed in one piece.

[0027] With this design, it is advantageous to compensate for material build-up if at least one recess extends to the common back wall.

[0028] In order to create sufficient space for the formation of material accumulation, in a preferred embodiment at least one recess at an end facing away from the conveying plane, preferably at the top, has a length, i.e. an extent in the conveying direction in the conveying plane, of at least 50 millimeters (mm), preferably of 55 to 99 mm.

[0029] To prepare the folding of the end section to the opposite fabric hose wall of the fabric hose section, the folding device, in a preferred embodiment viewed in the conveying direction, has an erection unit upstream of the hold-down elements for erecting the end section from a state extending the adjacent area of ​​the fabric hose section, i.e., preferably a substantially horizontal state during operation, to a state projecting from the adjacent area of ​​the fabric hose section, for example, substantially perpendicular to the conveying plane. The end section can, for example, be brought into the erect state by means of an erection plate.

[0030] In a preferred embodiment, the fold line between the end region and the adjacent region of the fabric hose section can be pre-embossed, preferably in the upright position of the end region. For this purpose, at least one embossing element, preferably at least one embossing roller, and preferably several embossing rollers arranged successively in the conveying direction, can be provided for embossing the fold line between the end region and the adjacent region of the fabric hose section. Preferably, the fold line is embossed in the upright position. The embossing element is preferably configured for embossing the fold line on the inside. The hold-down elements are configured to force down the outside of the end region, i.e., the visible side, so that the inside of the end region is approximated to the outside of the connecting section of the remaining fabric hose section.

[0031] For the formation of the folding bottom, a connecting device is preferably provided to connect the end area to the fabric tube wall.

[0032] Curvatures in the fabric tube section can lead to kinks in the fabric of the bottom section to be welded in the joining device, particularly when the end section and the adjacent section of the fabric tube section are welded together. To move the fabric tube section, especially the folded end section and the adjacent section of the fabric tube section, away from the holding unit towards the joining device in a substantially curvature-free manner, the bottom formation station, in a preferred embodiment, has a consolidation device. Preferably, the consolidation device guides at least one consolidation section, i.e., a section bordering the front edge of the fabric tube section, along a plane parallel to the transport plane, preferably along the transport plane itself, towards the joining device.It is advantageous if the consolidation section, upon exiting the consolidation device, is free of pockets between the end region and the adjacent region of the fabric tube section. Accordingly, the end region is advantageously folded essentially flat onto the adjacent region.

[0033] Preferably, the consolidation device is arranged along the transport direction in front of a guide device.

[0034] Preferably, the consolidation device has a lower consolidation element and an upper consolidation element, such that the end region of the already folded fabric tube section runs along the upper consolidation element and the adjacent region of the fabric tube section runs along the lower consolidation element in the transport direction through the consolidation device. A hold-down bar is preferably arranged between the consolidation elements, such that the hold-down bar is preferably located between the end region and the adjacent region of the fabric tube section. Preferably, the lower and upper consolidation elements run parallel to each other, preferably parallel to the transport plane. Preferably, the upper and / or the lower consolidation element has a receiving ramp at the leading end of the consolidation device along the transport direction to facilitate the receiving of the leading edge of the fabric tube section.

[0035] Preferably, the upper consolidation element is rigidly connected to the hold-down unit. Preferably, the lower consolidation element is formed by the conveying device.

[0036] In a preferred embodiment, the connecting device has a hot gas nozzle for expelling hot gas, preferably hot air, between the inside of the end region of the fabric hose section and the outside of the fabric hose wall of the fabric hose section. Alternatively, the connecting device can also be configured to bond the end region to the fabric hose wall.

[0037] To intimately connect the end section to the fabric hose wall, a pressing device is preferably provided for crimping the end section to the connecting section of the fabric hose wall. This results in a fabric hose section with a folded bottom, preferably with a pinch bottom.

[0038] To improve the accessibility of the fabric hose section in the soil formation station, a preferred embodiment includes a transfer device for moving at least individual parts of the soil formation station, preferably at least the holding unit, from an operating to an inactive position. It is advantageous if the fabric hose section is accessible along the entire longitudinal extent of the soil formation station in the inactive position. Furthermore, it is advantageous if the inactive position of the soil formation station facilitates the removal of material blockages in the soil formation station and / or the setup of the soil formation station before commissioning.

[0039] Preferably, the transfer device is further configured to move the hold-down bar away from the transport plane of the fabric hose section during the transfer from the operating to the inactive position, in particular by raising and / or laterally displacing it. It is advantageous if at least a section of a transport path near the fold line between the end region and the adjacent region of the fabric hose section is exposed during the transfer.

[0040] Preferably, the transfer device is further configured to move an upper element of the guide device and / or the upper consolidation element of the consolidation device and / or the positioning unit and / or the embossing unit away from the transport plane during the transfer from the operating to the inactive position, in particular by raising and / or laterally displacing them. It is advantageous if a gap, i.e., a vertical distance, between the transport plane and each of the holding unit and / or the upper element of the guide device and / or the upper consolidation element of the consolidation device and / or the positioning unit and / or a holding bar and / or the embossing unit is increased during the transfer to the inactive position.

[0041] Preferably, at least the hold-down bar is moved away from the hold-down unit during the transfer along a transfer plane, which is preferably parallel to the transport plane. Preferably, in the inactive position of the base-forming device, the hold-down bar is moved away from the hold-down device and / or the upper element of the guide device and / or the upper consolidation element of the consolidation device and / or the setup unit and / or the embossing unit, preferably at least in the transverse direction, i.e., laterally and / or vertically. Preferably, at least the hold-down bar is arranged in the inactive position of the base-forming device such that the hold-down device and / or the upper element of the guide device and / or the upper consolidation element of the consolidation device and / or the setup unit and / or the embossing unit do not project beyond the hold-down bar.

[0042] Preferably, the movement of the hold-down unit and / or the upper element of the guide device and / or the upper consolidation element of the consolidation device and / or the setting unit and / or the hold-down bar and / or the embossing unit is coupled during a transition from the operating to the inactive position.

[0043] Preferably, the transfer device is designed to be operated manually, in particular by actuating a transfer lever, or by a drive, for example an electric motor. Preferably, the transfer device has at least one transfer bridge that follows a translational movement during the transfer. Preferably, the hold-down unit and / or the upper element of the guide device and / or the upper consolidation element of the consolidation device and / or the setting unit and / or the hold-down bar and / or the embossing unit are mounted, preferably individually or in groups, on each of the transfer bridges.

[0044] In the inventive method for forming a folded bottom on a fabric tube section with a tape fabric made of plastic tape, preferably essentially of semi-crystalline thermoplastic, preferably of polyolefin, for example polypropylene (PP) or polyethylene (PE), or of polyester, for example polyethylene terephthalate (PET) or polylactide (PLA), at least the following steps are carried out:

[0045] Conveying the fabric hose section in the conveying direction along a conveying plane,

[0046] Folding an end area of ​​the fabric hose piece onto a fabric hose wall of the fabric hose piece, wherein the end area of ​​the fabric hose piece is increasingly forced further towards the fabric hose wall during folding with several hold-down parts, wherein the end area of ​​the fabric hose piece passes through a recess between the hold-down parts in each case, so that any material build-up of the end area can be received in the recess and compensated for at the hold-down part following the recess.

[0047] Regarding the advantages and technical effects, please refer to the explanations of the soil formation station.

[0048] In a preferred embodiment, the woven hose section comprises a tape fabric made of, preferably, stretched, plastic tapes, preferably of semi-crystalline thermoplastic, preferably of polyolefin, for example polypropylene (PP) or polyethylene (PE), or of polyethylene terephthalate (PET). A film, i.e., a homogeneous sheet structure, is preferably applied to the tape fabric. The film can comprise or consist of: polypropylene (PP) or polyethylene (PE), preferably stretched PP or stretched PE, in particular biaxially oriented polypropylene (BOPP) or biaxially oriented polyethylene (BOPE), or polyethylene terephthalate (PET), preferably oriented polyethylene terephthalate, in particular biaxially oriented polyethylene terephthalate (BOPET). The film can be unprinted or printed, e.g.,The tape can also be printed with a design, whereby, in the case of using a transparent film with a printed design, the side of the film facing the woven tape is preferably printed (counter-printed). Alternatively, the woven tube can have a coating applied to the woven tape. The coating can be formed by an extrusion coating that essentially comprises or consists of polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), polylactic acid (PLA), and / or mixtures thereof. In this case, the coating is a homogeneous layer on the woven tape. Both the film and the coating are preferably formed from a thermoplastic, sealable, i.e., weldable, polymer.

[0049] In a preferred embodiment, a pinch bottom is provided as the folding end. To prevent the escape of filling material through the pinch bottom, the pinch bottom forms a sealing closure, i.e., a gasket. For this purpose, at least one of the two opposing fabric tube walls of the folded end section has a recess, preferably stepped. As is known in the prior art, the recess can be produced in a previous manufacturing step by tearing off the fabric tube section along a stepped tear line from a fabric tube sheet. By folding over the end section with the, preferably stepped, recess on at least one of the fabric tube walls, the gasket is formed, which prevents the escape of filling material in the finished pinch bag.

[0050] In another preferred embodiment, the folded bottom is straight, i.e., the leading edges of the fabric tube walls extending into the end region are straight and identical. Fabric bags manufactured with such a folded bottom are also called padded bags.

[0051] The device according to the invention for manufacturing woven bags, preferably fold-bottom woven bags, preferably pinch-bottom woven bags or cushioning bags, comprises a bottom-forming station in one of the embodiments described above. In a preferred embodiment, the device comprises an unwinding station with which a flat woven web is unwound as the starting material for the woven bags. Alternatively, the woven web can already be in tubular form.

[0052] In a preferred embodiment, the device further comprises a station for forming tear lines at regular intervals along the fabric sheet or fabric tube. The tear lines are preferably formed by perforations and / or weakening. The station preferably comprises at least one perforation unit, preferably a laser unit, for weakening or perforating the fabric sheet or fabric tube along the tear lines. Alternatively, the station for forming the perforations can have a roller equipped with perforating blades that interact with a counter roller. The tear lines preferably have a stepped shape, which forms a sealing closure, i.e., a gasket, in the final pinch-bottom fabric bag to prevent the escape of filling material. The details of the stepped line are explained, for example, in EP 2 117 821 Bl.

[0053] In a preferred embodiment, the device, preferably in the transport direction after the station for forming the tear-off lines, has a tube-forming station with which the fabric flat web is folded over and processed into a fabric tube web with a longitudinal seam. The tube-forming station can also be configured to form longitudinal folds on the longitudinal sides of the fabric flat web.

[0054] In a preferred embodiment, the device has a rotary station downstream of the tear-off station in the transport direction for rotating the fabric tube sections by substantially 90° from a longitudinal transport position to a transverse transport position. Upstream of the rotary station, the longitudinal axes of the fabric tube sections are arranged substantially in the transport direction, and downstream of the rotary station, they are arranged substantially perpendicular to the transport direction.

[0055] In a preferred embodiment, the device has a delay station in the transport direction after the rotary station to delay the fabric hose pieces for further processing.

[0056] In a preferred embodiment, the device has, in the transport direction after the tear-off station, preferably in the transport direction after the delay station, the bottom formation station for forming fold-over bottoms, preferably pinch bottoms, on the fabric tube pieces, so that fold-over bottom fabric bags, preferably pinch bottom fabric bags, are obtained.

[0057] In a preferred embodiment, the device has a depositing station for depositing the folding bottom fabric bags, preferably the pinch bottom fabric bags, in the transport direction after the bottom formation station.

[0058] According to the invention, a method for manufacturing a woven bag, preferably a fold-over bottom woven bag, preferably a pinch-bottom woven bag, can also be carried out, in which the bottom formation is carried out according to one of the embodiment variants described above.

[0059] The method for manufacturing the fabric bag can further comprise at least one of the following steps, preferably all of the following steps, preferably sequentially: i. Unwinding a fabric sheet as starting material; ii. Forming tear lines at regular intervals in the fabric sheet, preferably by perforations and / or weakening, preferably by laser cutting, of the fabric sheet; iii. Folding over the fabric sheet and joining an overlap area of ​​the folded fabric sheet with a longitudinal seam, so that a fabric tube sheet is formed; iv. Tearing off the fabric tube piece from the fabric tube sheet; v.Rotating the fabric tube section by substantially 90° from a longitudinal transport position in which the longitudinal axis of the fabric tube section (from open end to open end) is arranged substantially in one transport direction, to a transverse transport position in which the longitudinal axis of the fabric tube section is arranged substantially perpendicular to the transport direction, vi. Forming a folding bottom, preferably a pinch bottom, on the fabric tube section, so that a folding bottom fabric bag, preferably a pinch bottom fabric bag, is obtained.

[0060] In a preferred embodiment, longitudinal folds are formed on the longitudinal sides of the fabric tube sheet, preferably during tube formation.

[0061] In a preferred embodiment, the conveying speed of the fabric hose section is reduced after rotation (step v . ) and before the formation of the folded bottom (step vi . ).

[0062] The invention is further explained below with reference to an exemplary embodiment shown in the drawings.

[0063] Fig. 1 schematically shows a device for the production of woven bags using the example of pinch-bottom bags, wherein a bottom-forming station according to the invention is used.

[0064] Figures 2 to 4 show the soil formation station for the formation of a folding soil using the example of a pinch soil.

[0065] In Fig. 5, the process of folding a piece of fabric tubing is outlined using the example of a folding device according to Fig. 2 to Fig. 4.

[0066] Figures 6 to 8 schematically show different designs of the soil formation station, in particular the folding device.

[0067] Fig. 9 shows a section of a woven bag wall.

[0068] Figures 10A to 10C and 10D to 10F show the process of transferring the soil formation station from an operating position to an inactive position by means of a transfer device, each in a perspective view and a front view. As can be seen from Figure 1, the device 1 has an unwinding station 2 with which a fabric web 3 is unwound. The fabric web 3 has a tape weave made of stretched plastic tapes, for example polypropylene. A film, preferably made of BOPP, is preferably applied to one side of the tape weave.

[0069] As can be seen in Fig. 1, the device 1 further comprises a station 4 for forming tear lines 5 at regular intervals along the fabric sheet 3. The tear lines 5 are formed by weakening or perforations in the material. The station 4 preferably comprises at least one perforation unit 6, here a laser unit, for weakening or perforating the fabric sheet 3 along the tear lines 5. Alternatively, the station 4 can have a roller equipped with perforating blades for forming the perforations, which interact with a counter roller (not shown). The tear lines 5 preferably have a stepped shape, which forms a seal in the final pinch-bottom fabric bag.

[0070] As can be seen from Fig. 1, the device 1 further comprises a tube forming station 7, with which the fabric sheet 3 is folded over along its longitudinal axis, an overlap area is formed, and this overlap area is provided with a longitudinal seam 8 to form a fabric tube sheet 9. Longitudinal folds can also be provided.

[0071] As can be seen from Fig. 1, the device 1 further has a tear-off station 10, with which the fabric tube sheet 9 is divided into individual fabric tube pieces 11 which are open at their end regions.

[0072] As can be seen from Fig. 1, the device 1 further has an intermediate transport and discharge station 12 for the intermediate transport of the fabric hose pieces 11 and the discharge of starting material.

[0073] As can be seen from Fig. 1, the device 1 further comprises a rotary station 13 for rotating the fabric tube sections 11 by 90° from a longitudinal transport position, in which the longitudinal axes of the fabric tube sections 11 are arranged in the transport direction 14A, to a transverse transport position, in which the longitudinal axes of the fabric tube sections are arranged in the transverse direction 14B perpendicular to the transport direction 14A, and still in the transport plane. Thus, the open ends of the fabric tube sections 11 are located at the front and rear ends before the rotary station, and at the sides of the fabric tube sections after the rotary station.

[0074] As can be seen from Fig. 1, the device 1 further has a delay station 15 for delaying the fabric hose pieces 11 for further processing.

[0075] As can be seen from Fig. 1, the device 1 further has a bottom formation station 16 for forming fold-over bottoms, preferably pinch bottoms 17, on the fabric tube pieces 11, so that fold-over bottom fabric bags 18, preferably pinch bottom fabric bags, are obtained.

[0076] As can be seen from Fig. 1, the device 1 further has a depositing station 19 for depositing the fabric bags 18.

[0077] As shown in Fig. 2, the soil formation station 16 has a conveying device 20 for conveying the fabric hose section 11 in a conveying direction 21.

[0078] The conveyor system 20 can, for example, include a magnetic chain conveyor.

[0079] The fabric tube section 11 (see Figures 2 to 8) has a first 11A and a second fabric tube wall 11B, which are fed to the soil formation station 16 in a flat, overlapping position by the conveying device 20. A folding device 22 folds over one of the open end regions of the fabric tube section 11. In doing so, one of the open end regions of the fabric tube section, which is formed from the end sections of the first 11A and the second fabric tube wall 11B, is folded over onto a connecting section 11C of the first fabric tube wall 11A. Furthermore, a hot gas nozzle 23 is provided, with which hot gas, preferably hot air, is expelled between the outer surface of the connecting section 11C of the first fabric tube wall 11A and the inner surface of the end region of the fabric tube section 11 facing the connecting section (see Figure 2).

[0080] As can be seen in Figs. 2, 3 and 4, a guide device 24 guides the end region of the fabric hose section 11 past the hot gas nozzle 23 in its folded state, i.e., folded over by essentially 180°. The guide device 24 spaced the inside of the end region from the outside of the adjacent first fabric hose wall 11A, creating a gap. The hot gas nozzle 23 was inserted into this gap. When the fabric hose section 11 was conveyed in the conveying direction 21, the hot gas was discharged into the gap by the hot gas nozzle 23. The hot gas partially melted the material.

[0081] A pressing device 25 presses the end region with the first fabric hose wall 11A of the fabric hose section 11, so that the thermal weld connection is formed (see Fig. 2 and Fig. 3). Following the pressing device 25 is the fabric bag 18 with the folded bottom, when a stepped tear line 5 is used as a pinch bottom (see Fig. 1).

[0082] According to the invention, the folding device 22 has a hold-down unit 26 with at least two hold-down elements 27 arranged successively in the conveying direction 21 (see Figures 2 and 3 as well as Figures 5 to 8). The hold-down elements 27 bring the end region of the fabric tube section 11 closer and closer to the outer surface of the adjacent region of the fabric tube section 11 in the conveying direction 21, which is formed by the first (upper) fabric tube wall 11A. With the last hold-down element 27' in the conveying direction 21, the end region is positioned substantially parallel to, preferably at an angle of less than 10°, for example, substantially 5°, but at a distance from, the adjacent region of the fabric tube section 11. Alternatively, the end region is positioned substantially parallel to, preferably at an angle of less than 10°, for example, substantially 0°, with the last hold-down element 27' in the conveying direction 21.The fabric hose section 11 is transferred from the holding unit 26 to the guide device 24 in the conveying direction 21. Subsequently, as described above, the hot gas welding of the folded end section to the adjacent section of the fabric hose section 11 is carried out.

[0083] The hold-down unit 26 has at least one recess or indentation 28 between two hold-down elements 27 arranged successively in the conveying direction 21. Along the recess 28, the end region of the fabric hose section 11 is arranged outwards, i.e. in the direction away from the adjacent region of the fabric hose section 11, without contact with the hold-down elements 27 (see Fig. 3, Fig. 5 to Fig. 8).

[0084] In the example shown, the hold-down unit 26 has at least three, here six, hold-down elements 27, which are connected to each other in pairs via a recess 28, here exactly one. The recess 28 serves to release a material build-up, i.e., a material bead that forms section by section, at the end of the fabric hose section 11 (see Fig. 3 and Fig. 5). Thus, the material build-up can form freely outwards in the area of ​​the recess 28 before it is smoothed out by the following hold-down element 27.

[0085] In the example shown, the hold-down elements 27, as can be seen particularly in Figures 2 and 3 as well as in Figures 5 to 8, are positioned at increasingly shallower angles to the conveying plane in the conveying direction 21. The hold-down elements 27 have hold-down edges 27A on the side of the end region of the fabric hose section, along which the end region of the fabric hose section 11 slides during conveying in the conveying direction 21. The hold-down edges 27A extend in planes that are essentially parallel to the fold line between the end region and the adjacent region of the fabric hose section 11. These planes are each arranged at acute angles to the conveying plane, with the acute angles decreasing in the conveying direction 21. The lower end, i.e.,The end of each retaining edge 27A facing the fold line between the end region and the adjacent region of the fabric hose section 11 is positioned further forward in the conveying direction 21 than the upper end, i.e., the end furthest from the fold line, of the respective retaining edge 27A. This ensures that the end region of the fabric hose section 11 is contacted first by the lower end and only then by the upper end of the retaining edge 27A. In the example shown, the retaining edges 27A are curved, with the slopes of the retaining edges 27A increasing from their lower ends to their upper ends as they approach the conveying plane.

[0086] As shown in Fig. 4, the individual hold-down elements 27 are connected to each other via a common back wall 27B, which is preferably elongated in the conveying direction. In the example shown, the hold-down elements 27 and the common back wall 27B are formed integrally. Thus, in the example shown, the hold-down unit 26 has no detachable connections, so that the hold-down unit 26 does not need to be assembled.

[0087] As can be seen from Figures 2 to 8, the folding device 22, viewed in the conveying direction 21, has an adjustment unit 29 upstream of the hold-down unit 26 for adjusting the end section from a state extending the adjacent area of ​​the fabric tube section 11 (i.e., horizontally) to a state projecting away from the adjacent area of ​​the fabric tube section 11. In the example shown, the end section of the fabric tube section 11 is adjusted by essentially 90° by the adjustment unit 29 before the end section is forced from the outside towards the adjacent area of ​​the fabric tube section 11 by the hold-down unit 26. As shown particularly in Figure 4, the adjustment unit 29 can, for example, have a curved adjustment element 30, so that the end section is adjusted from the state lying flat on the conveying plane to the angled state as it slides along the adjustment element 30.

[0088] Figures 3 to 8 further show a retaining strip 34, which holds the folded edge of the fabric hose section 11 along the setting unit 29 and the holding unit 26 as close as possible to the setting element 30 or the holding parts 27. Advantageously, the retaining strip 34 prevents lateral slippage or misalignment of the fabric hose section 11. To facilitate threading into the setting unit 29, the retaining strip 34 is bent at its leading end (as viewed in the conveying direction).

[0089] In the example shown, as can be seen from Figures 3 to 8, an embossing unit 31 with at least one embossing element 32 is provided, which is designed to pre-emboss the fold line between the end region and the adjacent region of the fabric hose section 11 in the conveying direction 21 between the setting unit 29 and the holding unit 26. In the example shown, three embossing elements 32 in the form of embossing rollers 33 are provided, which can be arranged, for example, at an angle of 30° to 60°, in particular substantially 45°, to the conveying plane. The embossing rollers 33 are passively rotated by the conveying device 20 when the fabric hose section 11 is conveyed.

[0090] Figures 3 to 6 show the process of folding over the end area of ​​the fabric hose piece 11.

[0091] Figures 6A and 6B show another embodiment in which the hold-down edges 27A are formed on hold-down bars. In the example shown, the hold-down bars are connected to the back wall 27B via connecting webs.

[0092] Figures 7A and 7B show another embodiment, which differs from the embodiment of Figure 8 by a simpler design of the hold-down elements 27. Figure 7C shows an embodiment with seven hold-down elements 27 and a consolidation device 36.

[0093] Fig. 9 schematically shows a section of a fabric tube wall onto the inside of the tube wall.

[0094] Figures 10A to 10F show the bottom-forming station 16 in various stages of transition from an operating position to an inactive position. For this purpose, a transition device 40 is provided for transitioning the hold-down unit 26, the hold-down bar 34, the upper element 36a of the guide device 24, the upper consolidation element 36a of the consolidation device 36, the actuating unit 29 and the embossing unit 31 from an operating position to an inactive position.

[0095] The transfer device 40 is designed to move the hold-down bar 34 and the embossing unit 31 laterally away from the transport plane of the fabric web 3 during the transfer from the operating to the inactive position.

[0096] The transfer device 40 is further equipped to move the hold-down bar 34, the embossing unit 31, the hold-down unit 26, the upper element 36a of the guide device 24 and the upper consolidation element 36a of the consolidation device 36 and the setting unit 29 vertically upwards during the transfer from the operating to the inactive position.

[0097] During the transition from the operating to the inactive position, the hold-down bar 34 and the embossing unit 31 are moved away from the hold-down unit 26.

[0098] The transport section 39 near the fold line between the end area and the adjacent area of ​​the fabric hose section 11 is easily accessible in the inactive position.

[0099] The movements of the hold-down unit 26, the upper element 24a of the guide device 24, the upper consolidation element 36a of the consolidation device 36, the setting unit 29, the hold-down bar 34 and the embossing unit

[0100] 31 are linked together during a transition from operational to inactive status.

[0101] The transfer is effected by actuating a transfer lever 38. The rotary movement of the transfer lever 38 is translated into translational movements of transfer bridges 37a-e, so that the hold-down unit 26, the upper element 24a of the guide device 24, the upper consolidation element 36a of the consolidation device 36, the setting unit 29, the hold-down bar 34 and the embossing unit 31j are each moved into a position corresponding to the inactive position of the bottom-forming device 16.

[0102] The transfer bridges 37a, 37b are connected to the hold-down bar 34. The upper element 36a of the consolidation device is rigidly connected to the hold-down unit 26. The transfer bridges 37d, 37e are connected to the setting unit 29. The transfer bridge 37c is connected to the embossing unit 31.

[0103] Reference number for remote list:

[0104] 1 Device

[0105] 2 processing stations

[0106] 3 Fabric flat sheet

[0107] 4 Station

[0108] 5 tear-off lines

[0109] 6 perforation unit

[0110] 7 Hose formation station

[0111] 8 Longitudinal seam

[0112] 9 Fabric hose conveyor

[0113] 10 Tear-off stations

[0114] 11 piece of fabric hose

[0115] 11A first fabric hose wall

[0116] 11B second fabric hose wall

[0117] 11C Connection section of the first fabric tube wall

[0118] 12 Discharge Station

[0119] 13 Rotating Station

[0120] 14A Transport direction

[0121] 14B Transverse direction

[0122] 15 delay stations

[0123] 16 Soil formation station

[0124] 17 Pinch bottoms

[0125] 18 Umf old soil fabric bags

[0126] 19 Departure Station

[0127] 20 funding institution

[0128] 21 Direction of conveyance

[0129] 22 Folding device

[0130] 23 Hot gas nozzle

[0131] 24 Guide system

[0132] 24a Upper part of the guide device Pressing device Hold-down unit Hold-down parts ' in conveying direction last hold-down part A Hold-down edges B Common rear wall of the hold-down parts Recess On Actuating unit On s Part sheet Embossing unit Embossing element Embossing rollers Hold-down bar Bent end of the hold-down bar Consolidation device a Upper element of the consolidation device a-e Transfer bridges Transfer levers Transport section Transfer device

Claims

Claims:

1. Bottom formation station (16) for forming a folded bottom, preferably a pinch bottom, on a fabric tube section (11) with a tape fabric made of plastic tapes, preferably of substantially semi-crystalline thermoplastic, preferably of polyolefin, for example polypropylene (PP) or polyethylene (PE), or of polyester, for example polyethylene terephthalate (PET) or polylactic acid (PLA), comprising: a conveying device (20) for conveying the fabric tube section (11) in a conveying direction (21) along a conveying plane, a folding device (22) for folding an end region of the fabric tube section (11) onto a fabric tube wall (11A) of the fabric tube section (11), characterized in that the folding device (22) comprises a hold-down unit (26) with at least two hold-down parts (27) successive in the conveying direction (21), which are designed tothe end region of the fabric hose section (11) is increasingly brought closer to the fabric hose wall (11A) in the conveying direction (21), wherein a recess (28) is formed between each of the successive hold-down parts (27) in the conveying direction (21) to receive a material build-up in the end region of the fabric hose section (11).

2. Soil formation station (16) according to claim 1, characterized in that the hold-down unit (26) has at least three, preferably at least four, preferably at least five, for example at least six hold-down parts (27), wherein a recess (28) is formed between successive hold-down parts (27).

3. Soil formation station (16) according to claim 1 or 2, characterized in that the hold-down parts (27) each have a hold-down edge (27A) for guiding the end region of the fabric tube piece (11A).

4. Soil formation station (16) according to claim 3, characterized in that at least one recess (28) , preferably each recess (28) extends between the hold-down edges (27A) of two hold-down parts (27) following one another in the conveying direction (21).

5. Soil formation station (16) according to claim 3 or 4, characterized in that the hold-down edges (27A) extend in planes which are substantially parallel to the fold line between the end region and the adjacent region of the fabric tube piece (11), wherein the planes are positioned at acute angles to the conveying plane, wherein the acute angles from hold-down part (27) to hold-down part (27) decrease in the conveying direction (21).

6. Soil formation station (16) according to one of claims 3 to 5, characterized in that the end of at least one retaining edge (27A) , preferably each retaining edge (28A) , facing the fold line between the end region and the adjacent region of the fabric tube piece (11) is arranged in the conveying direction (21) in front of the end of the retaining edge (27) facing away from the fold line, so that the end region of the fabric tube piece (11) first meets the end of the retaining edge (27A) facing the fold line.

7. Soil formation station (16) according to one of claims 3 to 6, characterized in that at least one hold-down edge (27A) , preferably each hold-down edge (27A) , is bent, wherein the slope of the respective hold-down edge (27A) towards the conveying plane increases from the end facing the fold line to the end of the hold-down edge (27A) facing away from the fold line, preferably continuously.

8. Soil formation station (16) according to one of claims 1 to 7, characterized in that the folding device (22) has, viewed in the conveying direction, an erection unit (29) in front of the hold-down unit (26) for erecting the end region from a state extending the adjacent region of the fabric tube piece to a state projecting away from the adjacent region of the fabric tube piece (11).

9. Soil formation station (16) according to one of claims 1 to 8, characterized in that at least one embossing element (32) , preferably at least one embossing plate or embossing roller (33) , is provided for embossing the fold line between the end area and the adjacent area of ​​the fabric hose piece (11).

10. Soil formation station (16) according to one of claims 1 to 9, characterized in that a connecting device for connecting the end region with the fabric tube wall for forming the folded soil, preferably the pinch soil, is provided.

11. Soil formation station (16) according to claim 10, characterized in that the connecting device has a hot gas nozzle (23) for ejecting hot gas, preferably hot air, between the inside of the end region of the fabric hose piece (11) and the outside of the fabric hose wall (11A) of the fabric hose piece. (11) shows.

12. Soil formation station (16) according to claim 11, characterized in that a pressing device (25) is provided for pressing the end area connected with the fabric tube wall (11A).

13. Soil formation station (16) according to one of claims 1 to 12, characterized by a transfer device for transferring the hold-down unit (26), preferably also the actuating unit (29), from an operating position to an inactive position.

14. Method for forming a fold-over bottom, preferably a pinch bottom, on a fabric tube section with a tape fabric made of plastic tapes, preferably substantially made of semi-crystalline thermoplastic, preferably of polyolefin, for example polypropylene (PP) or polyethylene (PE), or of polyester, for example polyethylene terephthalate (PET) or polylactide (PLA), comprising the steps: Conveying the fabric hose section (11) in the conveying direction (21) along a conveying plane, Folding an end region of the fabric tube piece (11) onto a region of the fabric tube piece (11) adjacent to the end region, characterized in that the end region of the fabric tube piece (11) is forced downwards towards the region of the fabric tube piece (11) adjacent to the end region by means of several hold-down parts (27) during folding, wherein the end region of the fabric tube piece (11) passes through a recess (28) between the hold-down parts (27) to receive a material build-up of the end region.

15. Device (1) for the production of woven bags, preferably fold-bottom woven bags, preferably pinch-bottom woven bags, comprising: a bottom-forming station according to any one of claims 1 to 13.

Images