BR112016026891B1 - device and method for forming a bottom opening between bag sections in the region of the open end of a tubular bag body - Google Patents

Abstract

Device and method for forming a bottom opening (8) between the bag sections (2 ', 2' ') in the open end region (9) of a tubular bag body (2) with a transport device (3) for transporting the bag body (2) in a transport direction (5) transverse to its longitudinal extension (6), and with an opening device (7) to form the bottom opening (8) between the bag sections (2 ', 2 '') in the open end region (9) of the tubular bag body (2), where the opening device (7) comprises at least two expansion elements (10) that follow each other in the transport direction (5) of the tubular bag body (2) in the form of wedge elements (12, 12 ', 12' ', 12' '') with wedge surfaces (14, 14 ', 14' ') that ascend against the direction of rotation (13) , where the bag sections (2 ', 2' ') in the open end region (9) of the tubular bag body (2) can be dilated separately during transport in the transport device (3), where the wedge elements (12, 12 ', 12' ', 12' '') of successive expansion elements (10) at different wedge heights (h) that increase in the transport direction (5) of the tubular bag body (2) preferably normal to the support surface (4) for the tubular body (2 ) on the transport device (3).

Description

[001] The invention relates to a device for forming a bottom opening between bag sections in the region of the open end of a tubular bag body, with a transport device for transporting the bag body in a transverse transport direction to its longitudinal extension, and with an opening device to form the bottom opening between the bag sections in the region of the open end of the tubular bag body where the opening device comprises at least one rotating expansion element around an axis rotating geometry, the expansion element of which can be introduced during rotation between the bag sections in the region of the open end of the tubular bag body.

[002] In addition, the invention relates to a method for forming a bottom opening between bag sections in the region of the open end of a tubular bag body, where the bag body is transported in a transport direction transverse to its longitudinal extension during transport, a rotating expansion element about a geometric axis of rotation is introduced between the bag sections in the region of the open end of the tubular bag body.

[003] Plants for producing bags are well known in the prior art. These plants comprise the provision of material in tubes that have been obtained either by producing tubular material screens, or by joining the longitudinal edges of flat material screens together to form a tubular structure, cutting the material into tubes to form tubular bag bodies of suitable length , and forming a bag bottom by properly opening, folding and closing an open end of the tubular bag body. Several solutions have been proposed in the prior art for opening the bottom of the bag.

[004] The device for pulling open transverse bottoms in a paper tube is known from DE 640 287 C, where the two tube layers of a tube section are separated from each other with the help of a separating finger. When the tube moves forward, a single expansion disc passes between the two layers of tube, the shell of whose expansion disc extends from one end to an enlarging wedge. The expansion disc thus penetrates even more deeply during the rotation through two further layers of the tube, as a result of which the bottom of the tube is evenly separated.

[005] The known modality, however, has the disadvantage that the expansion of the ends of the tube takes place over a comparatively small distance over wedge to accentuated surfaces. Malfunctions can thus occur.

[006] In addition, DE 1 611 701 discloses a device for opening the ends of pieces of pipe which lie flat, transported transversely in the production of transverse bags and pouches in bottom forming machines. In a variant of the mode for continuously operating bottom forming machines, tube sections are transported after several processing stations in a transverse position, by means of a surrounding handle chain. A stationary pair of suction boxes comprising rows of suction holes is provided to open the bottom of the tube. The suction boxes are connected by pipes to a vacuum pump. The suction boxes are placed diverging only a few millimeters in the direction of transport. The known modality is not designed or suitable to allow the penetration of an expansion disc, or similar, between the layers of tube. On the contrary, the carrier plate in the prior art comprises, on the one hand, a compressed air nozzle from which the air flow is directed to the air space between the two layers of film. On the other hand, two other counterparts of suction boxes are required, with which the open pull and deposition of the transverse bottom are performed.

[007] A bottom forming device for cross-bottom bag machines is known from DE 912.045, where a bottom forming element such as crescent is provided, which can be moved to a pre-opened tube end. The bottom forming element as a crescent rotates around a pivot pin that is rotatably adjusted to a lever arm of a double lever, rotatably mounted. The lever arm is controlled by means of a cam or by means of a connecting rod equipped with articulated joints at its ends, and a double lever with a roller. As a result of the oscillating pin oscillating the bottom forming element around the pivot center, the bottom forming element performs an oscillating movement separate from the rotary movement brought about by gear wheels.

[008] However, this modality is disadvantageously unreliable, since the fund-forming element as increasing cannot always ensure a sufficient fund opening. Malfunctions can therefore arise in the prior art, which can lead to malfunctions. In addition, the assembly of the bottom forming element is comparatively complex.

[009] In addition, bottom opening stations with rotating expansion tools, with an upper and a lower part, have been used in the preceding technique, which are moved apart from each other by means of a mechanism during the rotary movement . Such multi-part expansion tools, however, have the disadvantage of being expensive in terms of design and susceptible to defects. In addition, extensive adjustments to such expansion tools may be required.

[0010] Different types of devices for opening tube bottoms are known, for example, from WO 2012/049040 or AT 406 755 B.

[0011] In contrast to this, the problem with the present invention is to provide a device for forming a bottom opening as mentioned in the introduction, which mitigates or eliminates the disadvantages of the prior art. Consequently, the invention on the one hand fits in with the task of producing the bottom openings with a high degree of precision and reliability in continuous operation, in which the structural expense for the device must be kept as low as possible. In addition, maintenance costs should be reduced. In addition, a high production speed must be made possible.

[0012] According to the invention, the rotating expansion element comprises a wedge element with at least one wedge surface that ascends against the direction of rotation, with whose wedge surface the bag sections in the region of the open end of the body of tubular bag may be dilated separately during its transport in the transport device to form the bottom opening between the bag sections in the region of the open end of the tubular bag body.

[0013] According to the invention, therefore, a wedge-shaped expansion element is used to open the bottom of the bag, the wedge surface of said expansion element ascending against the direction of rotation, that is, from a front end region to a rear end region for the bag body on the transport device. During transport of the tubular bag body through the opening device, the rotating wedge element is inserted between the bag sections that are located one above the other in the region of the open end of the tubular bag body, where the bag sections are pulled apart by the wedge surface of the wedge element that ascends towards the rear. By means of the wedge element the width of the opening of the bottom opening of the tubular bag body is continuously increased. Advantageously, therefore, the bottom opening in the region of the open end of the tubular bag body can be formed particularly reliably. The service life of the opening device can thus be increased considerably. The wedge element preferably comprises an essentially vertical rotary geometrical axis, that is, which runs normal to the support surface for the bag body in the transport device when the bag sections in the region of the open end of the tubular bag body are transported in a position horizontally through the opening device. In this modality, the ascending wedge surface is placed at an angle with the horizontal transport plane, where the wedge surface, depending on the modality, extends from the front end to the rear end in an oblique way upwards, or oblique down. Alternatively, the bag sections in the region of the open end of the bag-shaped tubular body can be folded, for example through 90 °, from the surface of a support and onto the transport device. In this embodiment, the wedge element can be placed rotatable around a horizontal rotating geometric axis. In this case, the wedge surface of the wedge element is placed ascending in a horizontal plane against the direction of rotation. The rotational movement of the wedge element is adapted to the speed of transport along the transport device, in such a way that the bottom opening is formed in the region of the open end of the tubular body. Depending on the modality (bottom), openings can be formed in at least one, in particular also in both regions of the ends of the tubular bag body. For this purpose the plant can comprise, in each case, at least one wedge element on both sides, to form an opening on the bottom side and on the top side. The modality according to the invention is characterized by a low structural expense, where a mechanism for extending a multi-part expansion tool can be eliminated. In addition, the rotating assembly of the expansion tool is particularly simple. In addition, it is advantageous for the wedge-shaped expansion element to operate reliably in continuous operation with a high production speed. Advantageously, the maintenance cost can be kept low.

[0014] To form the bottom opening in the region of the open end of the tubular bag body with the required opening width, the opening device comprises at least two expansion elements, one following the other in the direction of transport of the bag body tubular. The preceding wedge element, seen in the direction of transport of the tubular bag body, is preferably provided to produce a first narrower opening width of the bottom opening, and the next wedge element, seen in the direction of transport, is provided to produce a second opening width wider than the bottom opening in the region of the open end of the tubular bag body.

[0015] For this purpose, the wedge elements of successive expansion elements have different wedge heights, increasing in the direction of transport of the tubular bag body, preferably normal to the support surface for the tubular bag body in the transport device. Consequently, the wedge height of the wedge element, i.e., the maximum extension of the wedge element normal to the support surface for the bag body in the transport device, increases from wedge element to wedge element, as seen in the direction of transport. Advantageously, the bottom opening is thus formed in stages using structurally direct means.

[0016] According to a particularly preferred embodiment, at least one expansion element, preferably each expansion element, comprises an adjustment device for adjusting the wedge height of the expansion element. In this mode, the wedge height is adjustable. A specific adjustment for a specific application can thus be made advantageously. The adjustment device may comprise, for example, a longitudinal guide that extends in the height direction for the adjustment of two sections or parts of the expansion element, in relation to each other. In addition, fastening means can be provided to secure the sections or parts of the expansion element in the relative position adjusted relative to each other.

[0017] To expand the bag sections, in the region of the open end of the bag body, spaced apart from each other in opposite directions, it is advantageous that the wedge element comprises two wedge surfaces diverging from each other in the direction of transport, preferably one upper wedge surface and a lower wedge surface, where the upper wedge surface and the lower wedge surface are each preferably arranged at an acute angle with the support surface for the tubular bag body in the transport device. In the opening device, therefore, the upper bag section of the tubular bag body is preferably pushed upward through the upper wedge surface of the wedge element, while the lower bag section is pushed downward through the lower wedge surface of the element wedge. The bottom opening can thus be formed particularly reliably in the tubular bag body. The upper wedge surface and the lower wedge surface are preferably placed symmetrical with respect to the support surface for the tubular bag body in the transport device. The bag sections of the tubular bag body can thus be pushed apart evenly around the central plane formed by the support surface in the transport device, to form the bottom opening in the region of the open end of the tubular bag body.

[0018] In order to allow a continuous formation of the bottom opening in the tubular bag body, it is advantageous that the expansion elements comprise wedge elements that overlap during rotation in the direction of transport of the body of the tubular bag, where in the direction of transport, a the preceding wedge element comprises a cut-out for the passage of a next wedge element in the direction of transport. In this embodiment, the wedge elements are placed temporarily overlapping during the rotation movement, where the front edge region of the next wedge element in the transport direction passes through the cutout of the preceding wedge element in the transport direction. Advantageously, therefore, the next wedge element in the transport direction can already pass between the bag sections of the tubular bag body before the preceding wedge element in the transport region has left the tubular bag body. In this embodiment, malfunctions, in particular a stack of bag bodies from the opening device, are advantageously avoided in a reliable manner.

[0019] For opening the bottom region of conventional bag bodies, it has proved to be particularly advantageous that precisely three expansion elements are provided, which comprise wedge elements that overlap during rotation in the direction of transport, for introduction between the sections of bag in the region of the open end of the tubular bag body. This modality allows a continuous formation of the bottom opening, where a malfunction is largely prevented.

[0020] According to a particularly preferred embodiment, a wedge element comprises a region of the rear end when related to the direction of rotation, a support section to support a rear region of the tubular bag body when related to the direction of transport during introduction from the wedge surface of the next wedge element in the direction of transport to a front region of the tubular bag body. The tubular bag body can thus advantageously be kept in a particularly open state by means of a wedge element, while the next wedge element in the direction of transport passes into the region of the open end of the tubular bag body, to widen the bottom opening.

[0021] In this embodiment, it is advantageous that the support section of the wedge element comprises a front edge that is placed essentially at the same height as the rear end of the wedge surface when viewed in the direction of rotation. The height is relative here to the distance from the guide edge of the support surface to the tubular bag body in the transport device. The region of the open end in the tubular bag body is maintained in a partially open state through the leading edge of the wedge element, when the next wedge element penetrates the bottom region of the tubular bag body, to gradually increase the opening width of the bottom opening.

[0022] To enable, on the one hand, an arrangement of superposition of successive expansion elements, and on the other hand support of the tubular bag body in the partially opened current state, it is advantageous that the wedge element comprises the cutout for the passage of the element next wedge in the direction of transport between the wedge surface and the support section. Consequently, the wedge element comprises the wedge surface at the front end (seen in the direction of rotation) and the support section at the rear end where the cutout is provided between the wedge surface and the support section, to allow space for movement rotation of the next wedge element. The wedge elements are also partially placed overlapping by means of cutouts to prevent the region of the already partially open end of the tubular bag body from being able to close again.

[0023] To facilitate the introduction of the wedge element in the region of the open end of the tubular bag body, it is advantageous that the wedge element is curved in the form of an arc, in particular in the form of a circle arc in the direction of rotation. Consequently, the wedge elements are formed in an arc with respect to the support surface for the tubular bag body in the transport device. The bottom opening can thus be formed in a particularly reliable manner.

[0024] To adjust the expansion element in a rotating motion, it is advantageous that the wedge element is connected to an axis element that is coupled to a drive, and the rotating geometric axis of the axis element is preferably placed essentially normal on the support surface to the bag body in the transport device. Consequently, the wedge element preferably comprises an essentially vertical rotating geometrical axis, i.e., placed normal to the support surface on the transport device.

[0025] With respect to a structurally straightforward stable embodiment, it is advantageous that the wedge element comprises at least one plate part which is preferably placed essentially normal on the support surface for the bag body in the transport device, and which forms a surface of wedge on an extreme face. Consequently, the wedge surfaces are preferably formed on the upper and lower edge of a plate part which remains essentially vertical on the support surface of the transport device.

[0026] For production-related reasons, provision is preferably made, such that the wedge element comprises at least one disk part which is preferably placed essentially parallel to the support surface for the bag body in the transport device, which is connected to the region wedge outside the plate part comprising the wedge surface.

[0027] In order to allow the expansion element to penetrate the region of the open end of the tubular bag body, it is advantageous that the opening device comprises a preliminary opening station in the direction of transport, with which the bag sections in the end region of the tubular bag body can be transferred from a state in which they lie flat on top of each other to a state spaced apart from each other. In the preliminary opening station the bottom opening is opened to such an extent that the narrow end of the wedge element can penetrate between the bag sections in the region of the open end of the tubular bag body.

[0028] According to a preferred embodiment, the preliminary opening station comprises at least one guide element with a guide surface inclined in the direction of the transport direction for one of the bag sections in the region of the open end of the tubular bag body where the guide surface is connected to a suction element to suck the bag section against the guide surface. During passage through the preliminary opening station a bag section in the region of the open end of the tubular bag body is carried along the guide surface of the guide element, where the bag section is maintained in contact with the guide surface through the suction element. As a result of the inclined arrangement of the guide surface, one bag section is moved away from the other bag section during transport along the preliminary opening station, as a result of which, the bag sections in the region of the open end of the body of tubular bag are transferred from the state where they lie flat on top of each other at the entrance of the preliminary opening station, to the state spaced apart from each other and particularly opening the bottom opening.

[0029] In order to allow a direct transfer of the bag body from the preliminary opening station to the at least one expansion element, it is advantageous that the at least one guide element of the preliminary opening station is placed, seen in the direction of transport, overlapping with at least one expansion element. Consequently, the wedge element engages between the bag sections of the bag body as soon as the bag sections have been pulled apart from each other in the preliminary opening station to essentially the maximum opening width. A continuous transfer between the preliminary opening station and the formation of the bottom opening with the expansion element is thus advantageously achieved. In addition, opening devices between the preliminary opening station with the inclined guide surface and the expansion element are preferably not provided.

[0030] To open the bottom opening during transport of the tubular bag body, it is advantageous that a drive element is provided to drive the guide element with guide surfaces. When the guide element is moved, the bag section is held against the guide surface by means of the suction element.

[0031] In this embodiment, it is advantageous that the guide element comprises a guide belt, in particular an endless belt, connected to the drive element, on whose belt the guide surface is formed for one of the bag sections in the region of the bag. open end of the tubular bag body. Consequently, the suction opening is transported along with the guide belt when the tubular bag is transported through the preliminary opening station. In this embodiment, at least one drive roller can be provided as a drive element, on which the guide belt runs. Two drive rollers are preferably provided, around which an endless belt with the guide surface for the tubular bag body is wound.

[0032] To produce the bottom opening uniformly in the region of the open end of the tubular bag body, it is advantageous that the preliminary opening station comprises two guide elements with one in the direction of transport and divergent guide surfaces for the sections bag in the region of the open end of the tubular bag body. In a preferred embodiment, an upper guide element is provided with an upper guide surface that ascends upward in the direction of transport, and a lower guide element is provided with a lower guide surface that descends in the direction of transport. In an alternative embodiment, the tubular bag body in the region of the open end is inclined at right angles to the transport plane. In this mode, the guide elements of the preliminary opening station are placed horizontally, where the distance between the guide surfaces becomes increasingly greater in the direction of transport.

[0033] In order to hold the bag section against the guide surface during transport through the preliminary opening station, it is advantageous that the suction element comprises at least one suction opening provided on the guide surface for the purpose of sucking one of the bag sections . The suction opening is connected to a vacuum generating medium with which the associated bag section is sucked against the guide surface.

[0034] According to a particularly preferred embodiment, a suction opening is placed on the guide surface. In this embodiment, the bag section is held against the respective guide surface during transport through the preliminary opening station by means of a single suction opening. Surprisingly, this method proved to be more advantageous than suction belts with rows of regular suction holes used in the prior art, with which only a comparatively small opening angle was capable of being achieved. The reason for this limitation of the preceding technique must be found in the fact that successive suction openings should cause tensions in the bag body in case the bag body is opened beyond small angles, the extensions of which could release the bag body from the surface. -guide. For this reason, other preliminary opening devices, in particular a compressed air nozzle and counter-rotating suction box pairs, were provided in the prior art after the suction belts in the transport direction, to enable open folding of the bottom of the bag. In contrast, the arrangement of a single suction opening on the guide surface makes it possible for the bag body to be sucked against the guide surface, essentially in a punctual manner. The guide surface can thus have a comparatively large inclination angle in relation to the transport plane, without tensions occurring along the main extension of the bag section. Advantageously, the bag body is thus reliably held against the guide surface. As a result of the point suction of the bag section, the latter can be pulled apart on the one hand in a linear manner and on the other hand along a curve. Depending on the application, a vacuum chamber can be formed appropriately adjacent to the guide surface.

[0035] Furthermore, provision is preferably made such that the endless belt that constitutes the guide element comprises precisely two suction openings. In this embodiment, an endless belt is provided as a guide element that is provided with precisely two suction openings. The distance between the two suction openings preferably corresponds essentially to half the length, that is, half the gauge of the endless belt. When the one suction opening is placed against the guide surface during transport of the bag body through the preliminary opening station, the other suction opening is located against the side of the endless belt facing away from the bag body. The one suction opening is thus active while the other suction opening is inactive. Both suction openings may be inactive for a short period of time when the endless belt is circulating. In particular, this may be the case when both suction openings are located in the region of the drive rollers that drive the endless belt.

[0036] One embodiment is particularly preferable where the preliminary opening station comprises at least one vacuum generating unit, with a vacuum chamber adjacent to the guide surface of the guide element with the suction opening. The vacuum chamber is preferably placed in a housing within the guide element, which preferably comprises an endless belt. On the one hand, the vacuum chamber is connected via a suction line to a vacuum generating medium. The endless belt is passed over the other side of the vacuum chamber, said endless belt comprising the suction opening. The associated bag section is thus placed against the guide surface of the endless belt.

[0037] The problem underlying the invention is also solved by a method of the type mentioned in the introduction where the rotating expansion element comprises a wedge element with at least one wedge surface that ascends against the direction of rotation, with whose wedge surface the bag sections in the region of the open end of the tubular bag body are expanded apart from each other during their transport in the transport device, to form the bottom opening between the bag sections in the region of the open end of the tubular bag body.

[0038] The invention is explained in more detail below with the help of an example of a preferred modality which, however, is not designed to be limited. In the drawing:

[0039] figure 1a schematically shows a diagrammatic view of a plant for producing bags, where an opening device according to the invention is provided to open the extreme region of a bag body;

[0040] figure 1b shows schematically a part of a preliminary opening station of the plant according to figure 1a; and

[0041] figures 2 to 7 show schematically views of a part of the opening device according to figure 1a during the formation of the bag opening by means of wedge-shaped expansion elements that separate the sections of bag that separate separately they lie on top of each other in the region of the open end of the tubular bag body.

[0042] Figure 1a shows a part of a plant 1 for producing bags, where a mesh material, in particular made of woven material, is processed in several stations to form finished cross-bottom bags or cross-bottom valve bags. The plant 1 comprises a separating device (not shown) for the purpose of separating the material on canvas for tubular bag bodies 2. Tubular bag bodies 2 comprise two sections of bag 2 ', 2' 'which are situated on top of each other, where each bag section 2 ', 2' 'can be made up of a plurality of layers of different material. The tubular bag bodies 2 are transferred to the transport device 3. In the transport device 3, bag bodies 2 are successively transported on an essentially horizontal support surface 4 of the transport device 3 in flat deposited state in the transport direction 5 transverse to its geometric axis of longitudinal extension 6, shown diagrammatically in figure 2.

[0043] As can still be seen from figure 1a, see also figures 2 to 6, the transport device 3 is connected to an opening device 7 to form a bottom opening 8 between sections of bag 2 ', 2' 'in region of the open end 9 of the tubular bag body 2. The opening device 7 comprises a preliminary opening station 23 by means of which bag sections 2 ', 2' 'in the region of the open end 8 of the tubular bag body 9 they can be transferred from a flat deposited state on top of one another, to a state spaced apart from each other.

[0044] As can be seen from figure 1a, the preliminary opening station 23 comprises an upper guide element 24 with an upper guide surface 24 'which ascends upwards in the transport direction 5, and a lower guide element 25 with an lower guide surface 25 'which descends downwards in the transport direction 5. Conveyor belts are supplied as guide elements 24, 25 in the mode shown, said guide belts being driven by drive rollers 24' ', 24' ''. Guide elements 24, 25 are each connected to a suction element 26 to suck bag sections associated with bag 2 ', 2' '. Suction elements 26 each comprise at least one suction opening 26 'in the guide surface 24', 25 'of the endless belt. In the embodiment shown, each endless belt comprises precisely two suction openings 26 ', see figure 1b.

[0045] As can be seen from figure 1b, the preliminary opening station 23 comprises a vacuum generating unit 27 for each guide element 24, 25. The vacuum generating units 27 each comprise a vacuum chamber 27 'extending adjacent the guide surface 24', 25 'of the upper guide element 25 and lower 25. The vacuum chamber 27' is provided in a housing 27 '' which is placed inside the guide element 24, 25 To produce a vacuum at the suction opening 26 'of the guide element 24, 25 the vacuum chamber 27' is connected via a suction line 27 '' 'to a vacuum generating means (not shown), for example , a vacuum pump. When the tubular bag body 2 is transported through the preliminary opening station 23, the bag sections 2 ', 2' 'are placed against the guide surfaces 24', 25 'of the guide elements 24, 25, said surfaces- guide diverging from each other in the direction of transport 5. The bag sections 2 ', 2' 'are thus transferred continuously from the state that lie flat on top of each other at the entrance of the preliminary opening station 23 to the spaced state separated from each other and partially opening the bottom opening 8.

[0046] As can still be seen from figure 1a, the opening device 7 comprises a plurality of expansion elements 10 that follow the preliminary opening station 23 in the transport direction 5, said expansion elements being each mounted rotationally around a vertical axis of rotation 11. The bottom opening 8 of the tubular bag body 2 is opened by the preliminary opening station 23 sufficiently to expand elements 10 to be able to penetrate between bag sections 2 ' , 2 '' in the region of the open end 9 of the tubular bag body 2. During the rotating movement, the expansion elements 10 pass between sections of bag 2 ', 2' 'in the region of the open end 9 of the tubular bag body 2 , with this forming the bottom opening 9.

[0047] As can be seen from figure 1a, a bottom folding station 28 follows the opening device 7 in the transport direction 5, in whose bottom folding station the opening geometry is brought to a correct rectangular position with the aid of finger elements 29. Tubular bag bodies 2 can then be processed in a manner known per se, to form the finished bags.

[0048] Figures 2 to 7 show expansion elements 10 in different stages in the formation of the bag opening 8. Tubular bag bodies 2 can be transported through the opening device 7 in a state in which they lie flat on top of each other in one horizontal plane as shown in figures 3 to 7. Alternatively, the bottom region can be tilted at an angle during transport via the opening device 7, see figure 2 schematically.

[0049] According to figures 2 and 3, the tubular bag body 2 is transported correctly with the partially open bottom opening 8 from the preliminary opening station 23 to the expansion elements 10. According to figures 3 to 7, the opening width of the bottom opening 8 is gradually increased so that the bottom opening 8 is completely open after the expansion elements 10.

[0050] As can be seen from figures 2 to 7, rotatingly mounted expansion elements 10 each comprise a wedge element 12 on whose wedge surfaces 14 are formed said wedge surfaces that ascend against the direction of rotation 3 , that is, from the front end region to the rear end region. During transport of tubular bag bodies 2 in the transport device 3, wedge elements 12 with wedge surfaces 14 increasingly push separate reciprocally opposed bag sections 2 ', 2' 'in the region of the open end 9 of the tubular bag body 2, as a result, the bottom opening 8 is produced between bag sections 2 ', 2' 'in the region of the open end 9 of the tubular bag body 2. Each wedge element 12 comprises an upper wedge surface 14' for a section top bag 2 'and a bottom wedge surface 14' 'for a bottom bag section 2' '. The wedge surfaces 14 ', 14' 'of wedge elements 12 are each arranged at an acute angle with the horizontal support surface 4 for the tubular bag body 2 in the transport device 3.

[0051] As can still be seen from figures 2 to 7, the wedge element 12 is connected to an axis element 15 that is placed essentially vertical, that is, normal to the support surface 4 for the bag body 2 in the transport device 13, which is adjusted in a rotating motion by a drive (not shown). In the embodiment shown, wedge surfaces 14 are formed on plate elements that are essentially vertically located 16. The front wedge element 12 'seen in the direction of transport 5, comprises a single plate element 16. The intermediate wedge element 12' 'seen in the transport direction 5 and the rear wedge element 12 '' 'seen in the transport direction 5 each comprises a part of the upper plate 16' comprising an upper wedge surface 16 'on an upper end face of a plate part plate lower 16 '' comprising lower wedge surface 14 '' on an extreme lower face. Plate elements 16, 16 ', 16' 'are curved in plan view, in the form of an arc of a circle corresponding to the direction of rotation 13. In addition, wedge elements 12 comprise disc parts 17 that essentially extend in a horizontal plane and that, on the one hand, they are coupled to the axis element 15, and on the other hand in the outer edges regions support parts plates 16 with wedge surfaces 14, 14 ', 14' '.

[0052] As can still be seen from figures 2 to 7, the opening device 7 comprises, in the embodiment shown, three expansion elements 10 following each other in the transport direction 5 of the tubular bag body 2. Individual expansion elements 10 comprise wedge elements 12 that have different wedge heights h that grow in the transport direction 5 of the tubular bag body 2. The wedge height h is measured here by the distance between the rear end of the wedge surface 14 seen in the direction of rotation 11 and the support surface 4 for tubular bag body 2 in the transport device 3. The opening width of the bottom opening 8, see figure 6, is increased from wedge element 12 to wedge element 12.

[0053] As can still be seen in figures 2 to 7, wedge elements 12 are partly overlapping by means of cutouts 12 during rotation, seen in the direction of transport 5, to achieve a continuous increase in the opening width b of the opening bottom 8. For this purpose, the front wedge element 12 'seen in the transport direction 5 comprised a cutout 18' for the passage of intermediate wedge element 12 '' following in the transport direction 5. Correspondingly, the intermediate wedge element 12 '' comprises a cutout 18 '' to allow space for the rotary movement of the rear wedge element 12 '' seen in the direction of transport 5.

[0054] As can still be seen from figures 2 to 7, the wedge element 12 comprises support sections 19 in a region of the rear end, when related to the direction of rotation 13, by means of which supporting sections rear sections 20 of sections bag 2 ', 2' 'when related to the transport direction 5, are kept in the current opening position while the wedge surface 14 of the wedge element 12, following in the transport direction 5 is introduced in the front regions 21 of the bag sections 2 ', 2' 'of the same bag body 2. For this purpose, support sections 19 of the wedge element 12 comprise at least one leading edge 22, in the embodiment shown an upper leading edge 22'and a lower leading edge 22' ' which are placed at essentially the same height as the rear end, seen in the direction of rotation 13, of associated wedge surfaces 14 ', 14' 'of the respective wedge element 12.

[0055] In the embodiment shown, the front wedge element 12 'seen in the direction of transport 5, on the one hand comprises support sections 19' which are designated for upper bag section 2 'and lower bag section 2' 'of the tubular bag body 2. The transfer of the tubular bag body 2 from the front wedge element 12 'to the intermediate wedge element 12' 'can thus take place reliably. On the other hand, the intermediate wedge element 12 '' seen in the direction of transport 5, comprises corresponding support sections 19 '' to carry out a reliable transfer of bag body 2 to the rear wedge element 12 '' seen in the direction of transport 5 .

[0056] The terms "lower" and "upper" for the arrangement of various components such as wedge elements, are used in the present description as an example for a preferred operating position, in which bag sections 2 ', 2' ' in the region of the open end 9 of the tubular bag body 2 they are transported in a horizontal position. However, a modality can of course be provided, where sections of bag 2 ', 2' 'are, for example, folded by 90 ° from the transport plane. In this embodiment, the components of the plant, such as wedge elements 12, are then placed inclined by a corresponding angle.

Claims (19)

1. Device for forming a bottom opening (8) between bag sections (2 ', 2' ') in the region of the open end (9) of a tubular bag body (2), with a transport device (3) for transporting the bag body (2) in a transport direction (5) transverse to its longitudinal extension (6) and with an opening device (7) to form the bottom opening (9) between the bag sections (2 ', 2' ') in the region of the open end (9) of the tubular bag body (2), where the opening device (7) comprises at least one swelling element (10) rotating about an axis of rotation ( 11) whose expansion element can be introduced during rotation between the bag sections (2 ', 2' ') in the region of the open end (9) of the tubular bag body (2), characterized by the fact that the opening device ( 7) comprise at least two expansion elements (10) following each other in the direction of transport (5) of the tubular bag body (2), where each expansion element ro (10) comprises a wedge element (12, 12 ', 12' ', 12' '') with at least one wedge surface (14, 14 ', 14' ') that ascends against the direction of rotation (13) , whereby the bag sections (2 ', 2' ') in the region of the open end (9) of the tubular bag body (2) can be dilated separately during their transport in the transport device (3) to form the opening bottom (9) between the bag sections (2 ', 2' ') in the region of the open end (9) of the tubular bag body (2) and by the wedge elements (12, 12', 12 '', 12 '' ') of successive expansion elements (10) have different wedge heights (h) increasing in the transport direction (5) of the tubular bag body (2). Device according to claim 1, characterized in that the wedge element (12) comprises two wedge surfaces diverging from each other in the direction of transport (5), preferably an upper wedge surface (14 ') and a surface lower wedge (14 ''), where the upper wedge surface (14 ') and the lower wedge surface (14' ') are preferably arranged at an acute angle with the support surface (4) for the body tubular bag (2) in the transport device (3). Device according to claim 1 or 2, characterized in that the expansion elements (10) comprise wedge elements (12, 12 ', 12' ', 12' '') that overlap during rotation in the direction of transport (5) of the tubular bag body (2), where a preceding wedge element in the transport direction (12, 12 ', 12' ') comprised a cutout (18) for the passage of a next wedge element in the transport direction ( 12, 12 '', 12 '' '). 4. Device according to claim 3, characterized in that precisely three expansion elements (10) are provided, which comprise wedge elements (12, 12 ', 12' ', 12' '') that overlap during rotation in the transport direction (5) for insertion between the bag sections (2 ', 2' ') in the region of the open end (9) of the tubular bag body (2). Device according to any one of claims 1 to 4, characterized in that a wedge element (12, 12 ', 12' ', 12' '') comprises in a region of the rear end when related to the direction of rotation ( 13), a support section (19, 19 ', 19' ') to support a rear region (20) of the tubular bag body (2), when related to the transport direction (5) during the introduction of the wedge surface (14) of the next wedge element (12, 12 '', 12 '' ') in a front region (21) of the tubular bag body (2). 6. Device according to claim 5, characterized in that the support section (19, 19 ', 19' ') of the wedge element (12, 12', 12 '', 12 '' ') comprises a leading edge (22) which is placed essentially at the same height as the rear end of the wedge surface (14, 14 ', 14' ') when viewed in the direction of rotation (13). Device according to claim 5 or 6, characterized in that the wedge element (12, 12 ', 12' ', 12' '') comprises the cutout (18) for the passage of the next wedge element (12, 12 '', 12 '' ') in the direction of transport (5) between the wedge surface (14, 14', 14 '') and the support section (19, 19 ', 19' '). Device according to any one of claims 1 to 7, characterized in that the wedge element (12, 12 ', 12' ', 12' '') is curved in the form of an arc, in particular in the form of an circle arc in the direction of rotation (13). Device according to any one of claims 1 to 8, characterized in that the wedge element (12, 12 ', 12' ', 12' '') is connected to an axis element (15) that is coupled to a drive and the axis of rotation 11 of the axis element is preferably placed essentially normal on the support surface (4) for the bag body (2) in the transport device (3). Device according to any one of claims 1 to 9, characterized in that the wedge element (12, 12 ', 12' ', 12' '') comprises at least one plate part (16, 16 ', 16' ') which is preferably placed essentially normal on the support surface (4) for the bag body (2) in the transport device (3) and which forms a wedge surface (14, 14', 14 '') on one face extreme. Device according to claim 10, characterized in that the wedge element (12, 12 ', 12' ', 12' '') comprises at least one disk part (17) which is preferably placed essentially parallel to the surface of support (4) for the bag body (2) in the transport device (3) and which is connected in the outer edge region to the plate part (16) comprising the wedge surface (14, 14 ', 14' '). Device according to any one of claims 1 to 9, characterized in that the opening device (7) comprises a preliminary opening station (23) with which the bag sections (2 ', 2' ') in the open end region (9) of the tubular bag body (2) can be transferred from a state in which they lie flat, one on top of the other, to the state spaced apart from each other. Device according to claim 12, characterized in that the preliminary opening station (23) comprises at least one guide element (24, 25) with a guide surface (24 ', 25') inclined in the direction of transport direction (5) for one of the bag sections (2 ', 2' ') in the region of the open end (9) of the tubular bag body (2), where the guide surface (24', 25 ') is connected to a suction element (26) to suck the bag section (2 ', 2' ') against the guide surface (24', 25 '). 14. Device according to claim 13, characterized in that a drive element (24 '', 24 '' ') is provided to drive the guide element (24, 25) with the guide surface (24', 25 '). Device according to claim 14, characterized in that the guide element (24, 25) comprises a guide belt, in particular an endless belt, connected to the drive element (24 '', 24 '' ' ) on whose belt the guide surface (24 ', 25') is formed for one of the bag sections (2 ', 2' ') in the region of the open end (9) of the tubular bag body (2). Device according to any one of claims 13 to 15, characterized in that the preliminary opening station (23) comprises two guide elements (24, 25) with diverging guide surfaces (24 ', 25') in the direction of transport (5) for the bag sections (2 ', 2' ') in the region of the open end (9) of the tubular bag body (2). Device according to any one of claims 13 to 16, characterized in that the suction element 26 comprises at least one suction opening (26 ') provided in the guide surface (24', 25 ') for the purpose of suck one of the bag sections (2 ', 2' '). 18. Device according to claim 17, characterized in that the preliminary opening station (23) comprises at least one vacuum generating unit (27) with a vacuum chamber (27 ') adjacent to the guide surface (24 ', 25') of the guide element (24, 25) with the suction opening (26). 19. Method for forming a bottom opening (8) between the bag sections (2 ', 2' ') in the region of the open end (9) of a tubular bag body (2), where the bag body (2 ) is transported in a transport direction (5) transverse to its longitudinal extension (2a) and, during transport, an expansion element (10) that rotates around a geometric axis of rotation (11) is introduced between the sections of bag (2 ', 2' ') in the region of the open end (9) of the tubular bag body (2), characterized in that the opening device (7) comprises at least two expansion elements (10) that follow a to the other in the transport direction (5) of the tubular bag body (2), where each rotating expansion element (10) comprised a wedge element (12, 12 ', 12' ', 12' '') with at least one wedge surface (14, 14 ', 14' ') that ascends against the direction of rotation (13), where the wedge elements (12, 12', 12 '', 12 '' ') of successive expansion elements (10 ) have different heights wedge s (h) that grow in the transport direction (5) of the tubular bag body (2), where the bag sections (2 ', 2' ') in the region of the open end (9) of the body of the body tubular bag (2) are dilated separately during transport in the transport device (3) by the wedge surfaces (14, 14 ', 14' ') of the wedge elements (12, 12', 12 '', 12 '' ') to form the bottom opening (8) between the bag sections (2 ', 2' ') in the region of the open end (9) of the tubular bag body (2).

Images