EP3148788B1 - Apparatus and method of forming an open base at a bag body - Google Patents

Description

The invention relates to a device for forming a bottom opening between bag sections at the open end region of a tubular bag body, with a transport device for transporting the bag body in a transport direction transversely to its longitudinal extent, and with opening means for forming the bottom opening between the bag sections at the open end region of the tubular bag body wherein the opening means comprises at least one expansion element rotatable about a rotation axis, which is insertable at the rotation between the bag sections at the open end region of the tubular bag body.

The invention further relates to a method for forming a bottom opening between bag sections at the open end region of a tubular bag body, wherein the bag body is transported transversely to its longitudinal extent in a transport direction and during transport a spreading element rotating about an axis of rotation between the bag sections at the open end region of the tubular bag body is introduced.

Systems for the production of sacks have long been known in the art. These systems include the provision of material hoses, obtained either by producing tubular webs or joining the longitudinal edges of flat webs into a tubular structure, cutting the hoses into tubular sacks of suitable length and forming a sack by opening, folding and closing an open sack End of the tubular bag body. To open the sack, various solutions have been proposed in the prior art.

From the DE 640 287 C a device for mounting cross bottoms on a paper tube is known, wherein the two tube layers of a tube section are separated by means of a separating finger. As the hose moves on, a single expansion disc travels between the two tube layers, the sheath of which widens from a tip to a wedge becoming wider. Thus, the spreader penetrates deeper and deeper into the two wrapping layers of the tube during the rotation, whereby the tube bottom evenly is spread apart.

However, the known design has the disadvantage that the spreading of the hose end takes place over a relatively small distance over steep wedge surfaces. This may cause malfunction.

Another device for spreading sacks is in the US 5,279,095 described. Furthermore, the reveals DE 1 611 701 a device for opening the ends of transversely conveyed flat hose pieces in the manufacture of the cross bottoms of sacks and bags in soil making machines. In one embodiment variant for continuously operating floor making machines, tube sections are guided past various processing stations by means of a circulating gripper chain in a transverse position. To open the tube bottom a stationary suction box pair is provided, which has Sauglochreihen. The suction boxes are connected via pipes to a vacuum pump. The suction box are arranged diverging only a few millimeters in the transport direction. The known design is not intended and suitable to allow the penetration of a spreading disc or the like between the tube layers. In contrast, the support plate in the prior art on the one hand on a compressed air nozzle whose air flow is directed into the air gap between the two film layers. On the other hand, two more, counter-rotating Saugkastenpaare required with which the winding and laying of the crossbeam is completed.

From the DE 912 045 is a Bodenlegevorrichtung for Kreuzbodenbeutelmaschinen known, in which a sickle-like Bodenlegeorgan is provided, which can move into a pre-opened end of the hose. The sickle-like Bodenlegeorgan runs around an axis of rotation, which is rotatably mounted on a lever arm of a rotatably mounted double lever. The lever arm is controlled by a connecting rod provided with joints at its ends and a double lever with roller by an eccentric. By pivoting the axis of rotation of the Bodenlegeorgans around the fulcrum, the Bodenlegeorgan performs except the circulation caused by gear wheels pivotal movement out.

The DE 2232165 A1 describes a device for folding folding box flaps.

The US 4,156,336 discloses an apparatus for making envelopes.

However, this embodiment is disadvantageously unreliable, since the sickle-like Bodenlegeorgan can not always ensure a sufficient bottom opening. Therefore, malfunctions can occur in the prior art, which can lead to operational failures. In addition, the storage of Bodenlegeorgans is comparatively expensive.

In addition, in the prior art floor opening stations with rotating spreading tools have been used with an upper part and a lower part, which are moved apart during the orbital movement via a mechanism. However, such multi-part spreader tools are disadvantageously structurally complex and error-prone. In addition, extensive adjustments to such spreaders may be required.

Other devices for opening hose trays are, for example, from WO 2012/049040 or the AT 406 755 B known.

In contrast, the object of the present invention is to provide a device for forming a bottom opening, as stated at the beginning, which alleviates or eliminates the disadvantages of the prior art. Accordingly, the invention is the one hand to the goal of generating the bottom openings with high precision and reliability in continuous operation, the structural complexity of the device should be kept as low as possible. In addition, the maintenance effort should be reduced. Furthermore, a high production speed is to be made possible.

This object is achieved by a device according to claim 1 and a method according to claim 15. Preferred embodiments are given in the dependent claims.

According to the invention, the rotatable expansion element has a wedge element with at least one wedge surface rising counter to the direction of rotation, with which the sack sections at the open end region of the tubular sack body during its Transports on the transport device are spread apart to form the bottom opening between the bag sections at the open end portion of the tubular bag body.

To open the sack bottom, a wedge-shaped expansion element is therefore used according to the invention whose wedge surface increases counter to the direction of rotation, ie from a front end region to a rear end region, for the sack body on the transport device. During transport of the tubular bag body through the opening device, the rotating wedge element is inserted between the stacked bag sections at the open end region of the tubular bag body, wherein the bag sections are pressed apart by the wedge surface of the wedge element rising to the rear. By means of the wedge element, the opening width of the bottom opening of the tubular bag body is continuously increased. Advantageously, therefore, the bottom opening can be formed particularly reliably at the open end region of the tubular bag body. As a result, the service life of the opening device can be substantially increased. The wedge element preferably has a substantially vertical, ie perpendicular to the support surface for the bag body on the transport device extending axis of rotation, when the bag sections are conveyed at the open end of the tubular bag body in a horizontal position through the opening means. In this embodiment, the rising wedge surface is disposed at an angle to the horizontal transport plane, wherein the wedge surface extends obliquely upwards or obliquely downward depending on the version from the front end to the rear end. Alternatively, the bag sections may be bent at the open end region of the bag-shaped hose body, for example, by 90 ° from the support surface on the transport device. In this embodiment, the wedge element can be arranged to rotate about a horizontal axis of rotation. In this case, the wedge surface of the wedge member is arranged rising in a horizontal plane counter to the direction of rotation. The orbital motion of the wedge member is tuned with the transport speed along the transport means such that the bottom opening is formed at the open end portion of the tubular bag body. Depending on the version you can at least one, in particular at both end portions of the tubular bag body (bottom) openings are formed. For this purpose, the system may have at least one wedge element on both sides in each case in order to form the bottom or upper-side opening. The inventive design is characterized by low structural complexity, which can be dispensed with a mechanism for extending a multi-part spreader. In addition, the pivot bearing of the spreading tool is particularly simple. Furthermore, it is advantageous that the wedge-shaped expansion element works reliably in continuous operation with high production speed. Conveniently, the maintenance can be kept low.

In order to form the bottom opening at the open end region of the tubular bag body with the required opening width, the opening device has at least two spreading elements which follow one another in the transport direction of the tubular bag body. Preferably, the preceding in the transport direction of the tubular bag body preceding wedge element for producing a first, narrower opening width of the bottom opening and seen in the transport direction following wedge element for producing a second, wider opening width of the bottom opening at the open end portion of the tubular bag body is established.

For this purpose, the wedge elements of successive spreading elements have different, in the transport direction of the tubular bag body increasing wedge heights preferably perpendicular to the support surface for the tubular bag body on the transport device. Thus, the wedge height of the wedge member, i. the maximum extent of the wedge element perpendicular to the support surface for the bag body on the transport device, seen in the transport direction of wedge element to wedge element to. Advantageously, the bottom opening is thereby formed stepwise with structurally simple means.

According to a particularly preferred embodiment, at least one expansion element, preferably each expansion element, an adjusting device for adjusting the wedge height of the expansion element. In this version, the wedge height adjustable. Advantageously, such an application-specific adjustment can be made. The adjusting device may, for example, have a longitudinal guide extended in the vertical direction for adjusting two sections or parts of the spreading element relative to one another. Furthermore, locking means may be provided for locking the sections or parts of the expansion element in the adjusted relative position to each other.

In order to spread the bag sections apart in opposite directions at the open end region of the bag body, it is favorable if the wedge element has two wedge surfaces diverging in the transport direction, preferably an upper wedge surface and a lower wedge surface, wherein the upper wedge surface and the lower wedge surface are preferably each in an acute angle to the support surface for the tubular bag body are arranged on the transport device. In the opening device, therefore, the upper bag section of the tubular bag body is preferably pushed upwards by means of the upper wedge surface of the wedge element, the lower bag section being pressed down by means of the lower wedge surface of the wedge element. As a result, the bottom opening on the tubular bag body can be made particularly reliable. Preferably, the upper wedge surface and the lower wedge surface are arranged symmetrically with respect to the support surface for the tubular bag body on the transport device. As a result, the bag sections of the tubular bag body can be pressed apart uniformly around the center plane formed by the bearing surface on the transport device in order to form the bottom opening at the open end region of the tubular bag body.

In order to enable a continuous shaping of the bottom opening on the tubular bag body, it is advantageous if the spreading elements have overlapping wedge elements during the rotation in the transport direction of the tubular bag body, wherein a wedge element preceding in the transport direction has a recess for the passage of a wedge element following in the direction of transport. In this embodiment, the wedge members are temporarily during the orbital movement arranged overlapping, wherein the front end portion of the following in the direction of transport wedge element passes through the recess of the preceding in the transport direction wedge element. Advantageously, therefore, the wedge element following in the transport direction can already enter between the sack sections of the tubular sack body before the wedge element which precedes in the transport direction has still exited from the tubular sack body. Advantageously, malfunctions, in particular a jam of bag bodies in the opening device, are reliably avoided in this embodiment.

To open the bottom portion of conventional bag body, it has been found to be particularly advantageous if exactly three spreading elements are provided, which have during rotation in the transport direction overlapping wedge elements for insertion between the bag sections at the open end portion of the tubular bag body. This design allows a continuous formation of the bottom opening, with malfunction are largely avoided.

According to a particularly preferred embodiment, a wedge element at a rear end region with respect to the direction of rotation has a holding section for holding a rear region of the tubular bag body with respect to the transport direction during insertion of the wedge surface of the wedge element following in the transport direction into a front region of the tubular bag body. Advantageously, the tubular bag body can thus be held in a state partially opened by means of a wedge element, while the wedge element following in the transport direction moves into the open end region of the tubular bag body in order to broaden the bottom opening.

In this embodiment, it is advantageous if the holding portion of the wedge member has a leading edge, which is arranged substantially at the same height as the viewed in the direction of rotation rear end of the wedge surface. The height here refers to the distance of the leading edge of the support surface for the tubular bag body on the transport device. Due to the leading edge of the wedge element of the open end portion of the tubular Held bag body in a partially opened state when the following wedge member is immersed in the bottom portion of the tubular bag body to gradually increase the opening width of the bottom opening.

On the one hand to allow an overlapping arrangement of successive spreading elements and on the other hand holding the tubular bag body in the current, partially open state, it is advantageous if the wedge element between the wedge surface and the holding portion has the recess for the passage of the following in the transport direction wedge element. Accordingly, the wedge member at the (in the direction of rotation) front end of the wedge surface and the rear end of the holding portion, wherein between the wedge surface and the holding portion, the recess for the release of the rotational movement of the following wedge member is provided. The wedge elements are therefore also arranged partially overlapping by means of recesses in order to prevent the already partially opened end region of the tubular sack body from closing again.

In order to facilitate the insertion of the wedge element in the open end region of the tubular bag body, it is advantageous if the wedge element in the direction of rotation arcuate, in particular circular arc-shaped, curved. Accordingly, the wedge elements are formed arcuately with respect to the support surface for the tubular bag body on the transport device. As a result, the bottom opening can be formed particularly reliable.

In order to set the expansion element in rotary motion, it is advantageous if the wedge element is connected to a drive element coupled to a shaft element whose axis of rotation is preferably arranged substantially perpendicular to the support surface for the bag body on the transport device. Thus, the wedge member preferably has a substantially vertical, i. arranged perpendicular to the support surface in the transport device, axis of rotation.

With regard to a structurally simple, stable embodiment, it is favorable if the wedge element at least one preferably substantially perpendicular to the support surface for the bag body On the transport device arranged plate member which forms a wedge surface on one end face. Accordingly, the wedge surfaces are preferably formed on the upper or lower edge of a substantially perpendicular to the support surface in the transport device plate member.

For manufacturing reasons, it is preferably provided that the wedge element has at least one preferably arranged substantially parallel to the support surface for the bag body on the transport device disc part, which is connected at the outer edge region with the wedge surface having plate member.

In order to allow the expansion element to penetrate into the open end region of the tubular bag body, it is favorable if the opening device has a pre-opening station in the transport direction with which the bag sections can be transferred from a flat superimposed state into a spaced-apart state at the open end region of the tubular bag body are. In the pre-opening station, the bottom opening is released so far that the narrow end of the wedge element can enter between the bag sections at the open end region of the tubular bag body.

According to a preferred embodiment, the pre-opening station has at least one guide element with a guide surface inclined for the transport direction for one of the bag sections at the open end region of the tubular bag body, wherein the guide surface is connected to a suction element for sucking the bag section against the guide surface. When passing through the pre-opening station, the one bag section is conveyed along the open end region of the tubular bag body along the guide surface of the guide element, wherein the one bag section is held in contact with the guide surface by means of the suction element. Due to the inclined arrangement of the guide surface, the one bag section is removed from the other bag section during transport along the pre-opening station, whereby the bag sections at the open end region of the tubular bag body from the flat superimposed state at the entrance of Voröffnungsstation in the spaced apart, the bottom opening partially releasing state to be transferred.

In order to enable an immediate transfer of the bag body from the Voröffnungsstation to the at least one expansion element, it is advantageous if the at least one guide element of the Voröffnungsstation seen in the transport direction is arranged overlapping with the at least one expansion element. Accordingly, the wedge member engages between the bag sections of the bag body as soon as the bag sections in the pre-opening station have been pulled apart to substantially the maximum opening width. Advantageously, therefore, a continuous transition between the Voröffnungsstation and the formation of the bottom opening can be achieved with the expansion element. Further opening means between the Voröffnungsstation with the inclined guide surface and the spreader are preferably not provided.

To release the bottom opening during transport of the tubular bag body, it is favorable if a drive element is provided for driving the guide element with the guide surface. When moving the guide member of the bag section is held by means of the suction on the guide surface.

In this embodiment, it is advantageous if the guide element has a guide belt connected to the drive element, in particular an endless belt, on which the guide surface for one of the bag sections is formed at the open end region of the tubular bag body. Accordingly, the suction port is entrained with the guide belt when the tubular bag body is transported through the pre-opening station. As a drive element can be provided in this embodiment, at least one drive roller on which the guide belt runs. Preferably, two drive rollers are provided, around which an endless belt is wound with the guide surface for the tubular bag body.

In order to produce the bottom opening uniformly at the open end region of the tubular bag body, it is advantageous if the Voröffnungsstation has two guide elements with diverging in the transport direction guide surfaces for the bag sections at the open end portion of the tubular bag body. In a preferred embodiment, an upper guide element is provided with an upper guide surface rising upward in the transport direction and a lower guide element with a lower guide surface sloping down in the transport direction. In an alternative embodiment, the tubular bag body is angled at the open end region at right angles to the transport plane. In this embodiment, the guide elements of the pre-opening station are arranged horizontally, wherein the distance between the guide surfaces increases in the transport direction increasingly.

In order to keep the bag section on the guide surface during transport through the pre-opening station, it is favorable if the suction element has at least one suction opening provided on the guide surface for sucking one of the bag sections. The suction opening is connected to negative pressure generating means, with which the associated bag section is sucked to the guide surface.

According to a particularly preferred embodiment, exactly one suction opening is arranged on the guide surface. In this embodiment, the bag portion is held during transport through the Voröffnungsstation by means of a single suction port on the respective guide surface. This design has surprisingly proved to be cheaper than the suction belt used in the prior art with regular Sauglochreihen, with which only a relatively small opening angle could be achieved. This limitation of the prior art is due to the fact that the successive suction openings on opening the bag body over small angles beyond would cause stresses in the bag body, which could solve the bag body of the guide surface. For this reason, in the prior art in the transport direction to the suction belt further Voröffnungseinrichtungen, in particular a compressed air nozzle and counter-rotating suction box pairs, provided to the unfolding of the bag bottom enable. In contrast, the arrangement of a single suction opening on the guide surface makes it possible for the bag body to be sucked onto the guide surface substantially at points. Thus, the guide surface can have a comparatively large angle of inclination with respect to the transport plane, without creating stresses along the main extension of the bag section. Advantageously, the bag body is therefore reliably held on the guide surface. Due to the selective suction of the bag section this can be drawn on the one hand linear and on the other hand along a curve. Depending on the application, a vacuum chamber adjacent to the guide surface can be designed accordingly.

Furthermore, it is preferably provided that the endless belt forming the guide element has exactly two intake openings. In this embodiment, an endless belt is provided as a guide element, which is provided with exactly two suction openings. The distance between the two suction ports is preferably substantially equal to half the length (i.e., half the circumference) of the endless belt. If, during transport of the bag body through the pre-opening station, one suction opening is arranged on the guide surface, the other suction opening is located on the side of the endless belt facing away from the bag body. As a result, one intake opening is active while the other intake opening is inactive. For a short period of time when circulating the endless belt, both intake ports may be inactive. This may be the case in particular when both intake openings are in the region of drive rollers which drive the endless belt.

Particularly preferred is an embodiment in which the pre-opening station has at least one vacuum generating unit with a vacuum chamber adjacent to the guide surface of the guide member with the suction port. The vacuum chamber is preferably arranged in a housing within the guide element, which preferably has an endless belt. On the one hand, the vacuum chamber is connected via a suction line with the negative pressure generating means. On the other side of the vacuum chamber of the endless belt is passed, which has the suction port. This will the associated bag section applied to the guide surface of the endless belt.

The object underlying the invention is also achieved by a method of the initially mentioned type, in which the rotatable expansion element has a wedge element with at least one counter to the direction of rotation rising wedge surface with which the bag sections apart at the open end of the tubular bag body during its transport on the transport device are spread to form the bottom opening between the bag sections at the open end portion of the tubular bag body.

• Fig. 1a schematisch eine schaubildliche Ansicht einer Anlage zur Herstellung von Säcken, bei welcher eine erfindungsgemäße Öffnungseinrichtung zum Öffnen des Endbereichs eines Sackkörpers vorgesehen ist;
• Fig. 1b schematisch einen Teil einer Voröffnungsstation der Anlage gemäß Fig. 1a; und
• Fig. 2 bis 7 schematisch Ansichten eines Teils der Öffnungseinrichtung gemäß Fig. 1a beim Ausbilden der Sacköffnungs mittels keilförmiger Spreizelemente, welche die aufeinanderliegenden Sackabschnitte am offenen Endbereich des schlauchförmigen Sackkörpers auseinander spreizen.

The invention will be explained below with reference to a preferred embodiment, to which, however, it should not be limited. In the drawing show

• Fig. 1a schematically a perspective view of a plant for the production of sacks, in which an opening device according to the invention is provided for opening the end portion of a bag body;
• Fig. 1b schematically a part of a Voröffnungsstation the system according to Fig. 1a ; and
• Fig. 2 to 7 schematically views of a portion of the opening device according to Fig. 1a during formation of the sack opening by means of wedge-shaped spreading elements, which spread apart the stacked sack sections at the open end region of the tubular sack body.

Fig. 1a shows a part of a plant 1 for the production of sacks, wherein a material web, in particular of a fabric material, is processed in various stations to produce Kreuzboden- or Kreuzbodenventilsäcken. The system 1 has a separating device (not shown) in order to separate the material web into tubular bag bodies 2. The tubular bag body 2 consist of two superimposed bag sections 2 ', 2 ", wherein each bag section 2', 2" can be constructed of several layers of different material. The tubular bag bodies 2 are transferred to a transport device 3. In the transport device 3 be the bag body 2 successively on a substantially horizontal support surface 4 of the transport device 3 in a flat state in the transport direction 5 transversely to its in Fig. 2 be shown schematically longitudinal axis 6 promoted.

How out Fig. 1a , see. also Fig. 2 to 6 3, the transport device 3 is connected to an opening device 7 for forming a bottom opening 8 between the bag sections 2 ', 2 "at the open end region 9 of the tubular bag body 2. The opening device 7 has a pre-opening station 23, with which the bag sections 2' , 2 "at the open end portion 8 of the tubular bag body 9 from a flat superimposed state in a spaced-apart state can be transferred.

How out Fig. 1a can be seen, the Voröffnungsstation 23, an upper guide member 24 with an upward in the transport direction 5 upper guide surface 24 'and a lower guide member 25 with a downwardly sloping in the transport direction 5 lower guide surface 25'. In the embodiment shown, endless belts are provided as guide elements 24, 25, which are driven by drive rollers 24 ", 24" .The guide elements 24, 25 are each connected to a suction element 26 for sucking in the associated bag section 2 ', 2 ". The suction elements 26 each have at least one suction opening 26 'on the guide surface 24', 25 'of the endless belt. In the embodiment shown, each endless belt has exactly two intake openings 26 '(cf. Fig. 1b ).

How out Fig. 1b can be seen, the Voröffnungsstation 23 each have a vacuum generating unit 27 for each guide member 24, 25. The negative pressure generating units 27 each have a vacuum chamber 27 'which extends adjacent to the guide surface 24', 25 'of the upper 24 and lower guide member 25. The vacuum chamber 27 'is provided in a housing 27 "which is arranged inside the guide element 24, 25. In order to apply a negative pressure to the suction opening 26' of the guide element 24, 25, the vacuum chamber 27 'is connected via an intake line 27'" (not shown) negative pressure generating means, such as a Vacuum pump, connected. When the tubular sack body 2 is guided by the pre-opening station 23, the sack sections 2 ', 2 "are applied to the guide surfaces 24', 25 'of the guide elements 24, 25 diverging in the transporting direction 5. As a result, the sack sections 2', 2" become continuous the flat superimposed state at the entrance of Voröffnungsstation 23 in the spaced apart, the bottom opening 8 partially releasing state transferred.

How out Fig. 1a Furthermore, it can be seen, the opening means 7 in the transport direction 5 after the Voröffnungsstation 23 a plurality of spreading elements 10, which are each rotatably mounted about a vertical axis of rotation 11. The bottom opening 8 of the tubular bag body 2 is sufficiently opened by the pre-opening station 23 that the spreading elements 10 can penetrate between the bag sections 2 ', 2 "at the open end region 9 of the tubular bag body 2. During the rotary movement, the spreading elements 10 travel between the bag sections 2'. , 2 "at the open end portion 9 of the tubular bag body 2, wherein the bottom opening 8 is formed.

How out Fig. 1a Furthermore, the opening device 7 follows in the transport direction 5 a bottom folding station 28, in which the geometry of the opening is brought into a correct, right-angled position with the aid of finger elements 29. Thereafter, the tubular bag body 2 can be processed in a conventional manner to the finished bags.

In the Fig. 2 to 7 the spreading elements 10 are shown at various stages in the formation of the bottom opening 8. The tubular bag body 2 can in this case in a flat superimposed in a horizontal plane state, as in Fig. 3 to 7 shown to be conveyed through the opening device 7. Alternatively, the floor area can be angled during transport through the opening device 7 (see FIG Fig. 2 ).

According to Fig. 2 . 3 the tubular bag body 2 is transported straight with partially released bottom opening 8 of the Voröffnungsstation 23 to the spreading elements 10. According to Fig. 3 to 7 the opening width of the bottom opening 8 is gradually increased, so that the bottom opening 8 is completely released after the expansion elements 10.

How out Fig. 2 to 7 As can be seen, the rotatably mounted spreading elements 10 each have a wedge element 12, on which counter to the direction of rotation 13, ie from the front end region to the rear end region, rising wedge surfaces 14 are formed. When transporting the tubular bag body 2 on the conveyor 3, the wedge elements 12 with the wedge surfaces 14 push the opposite bag sections 2 ', 2 "at the open end portion 9 of the tubular bag body 2 increasingly apart, whereby the bottom opening 8 between the bag sections 2', 2" on open end portion 9 of the tubular bag body 2 is generated. Each wedge element 12 has an upper wedge surface 14 'for an upper sack section 2' and a lower wedge surface 14 "for a lower sack section 2". The wedge surfaces 14 ', 14 "of the wedge elements 12 are each arranged at an acute angle to the horizontal support surface 4 for the tubular bag body 2 on the transport device 3.

How out Fig. 2 to 7 Furthermore, the wedge element 12 is connected to a substantially vertical, ie perpendicular to the support surface 4 for the bag body 2 on the transport device 3, arranged shaft member 15 which is rotated by a (not shown) drive in rotary motion. In the embodiment shown, the wedge surfaces 14 are formed on substantially perpendicular plate elements 16. The front wedge element 12 'seen in the transport direction 5 has a single plate element 16. The central wedge element 12 "seen in the transport direction 5 and the rear wedge element 12 '" in the transport direction 5 each have an upper plate part 16' which has the upper wedge surface 14 'on an upper end side and a lower plate part 16 "which The plate elements 16, 16 ', 16 "are curved in a circular arc in plan view corresponding to the direction of rotation 13. In addition, the wedge members 12 extend substantially in a horizontal plane Disk parts 17, which are coupled on the one hand with the shaft member 15 and on the other hand, at the outer edge regions, the plate parts 16 with the wedge surfaces 14; 14 ', 14 "wear.

How out Fig. 2 to 7 Furthermore, it can be seen, the opening means 7 in the embodiment shown three in the transport direction 5 of the tubular bag body 2 successive spreading elements 10. The individual expansion elements 10 have wedge elements 12, which have different, increasing in the transport direction 5 of the tubular bag body 2 wedge heights h. The wedge height h is measured here by the distance between the viewed in the direction of rotation 11 rear end of the wedge surface 14 and the support surface 4 for the tubular bag body 2 on the conveyor 3. As a result, the opening width b of the bottom opening 8 (see. Fig. 6 ) wedge element 12 to wedge element 12 increases.

How out Fig. 2 to 7 seen further, the wedge elements 12 are seen during rotation in the transport direction 5 by means of recesses 18 partially overlapping arranged to achieve a continuous increase in the opening width b of the bottom opening 8. For this purpose, the front wedge element 12 ', seen in the transporting direction 5, has a recess 18' for the passage of the middle wedge element 12 "following in the transporting direction 5. Correspondingly, the middle wedge element 12" has a recess 18 "for releasing the rotational movement of the transport direction 5 seen rear wedge element 12 '''on.

How out Fig. 2 to 7 Furthermore, it can be seen, the wedge member 12 at a rear end portion 13 with respect to the rotational direction holding portions 19, with respect to the transport direction 5 rear portions 20 of the bag sections 2 ', 2 "are held in the current open state, while the wedge surface 14 of the following in the transport direction 5 Wedge element 12 in front portions 21 of the bag sections 2 ', 2 "of the same bag body 2 are introduced. For this purpose, the holding portions 19 of the wedge element 12 at least one leading edge 22, in the embodiment shown each have an upper leading edge 22 'and a lower leading edge 22 ", which at substantially the same height as that in the direction of rotation 13th seen rear end of the associated wedge surfaces 14 ', 14 "of the respective wedge element 12 are arranged.

In the embodiment shown, on the one hand, the front wedge element 12 ', viewed in the transport direction 5, has holding sections 19' which are associated with the upper sack section 2 'and the lower sack section 2 "of the tubular sack body 2. This makes it possible to take over the tubular sack body 2 from the front wedge element 12 'to the central wedge element 12 "be designed reliably. On the other hand, as seen in the transport direction 5 mean wedge element 12 "corresponding holding portions 19" in order to accomplish a reliable transfer of the bag body 2 to the rear in the transport direction 5 wedge element 12 '' '.

The terms "bottom" and "top" for the arrangement of various components, such as the wedge elements are used in the present disclosure by way of example for a preferred operating position, in which the bag sections 2 ', 2 "at the open end portion 9 of the tubular bag body 2 in a Of course, however, it is also possible to provide a design in which the bag sections 2 ', 2 "are bent, for example, by 90 ° from the transport plane. In this embodiment, then the components of the system, such as the wedge elements 12, arranged tilted by a corresponding angle.

Claims (15)

1. A device for forming a bottom opening (8) between bag sections (2', 2") at 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) for forming the bottom opening (8) between the bag sections (2', 2") at the open end region (9) of the tubular bag body (2), wherein the opening device (7) comprises at least one splaying element (10) rotatable about a rotary axis (11), which splaying element can be introduced during rotation between the bag sections (2', 2") at the open end region (9) of the tubular bag body (2), characterised in that the opening device (7) comprises at least two splaying elements (10) following one another in the transport direction (5) of the tubular bag body (2), wherein each rotatable splaying element (10) comprises a wedge element (12; 12', 12", 12''') with at least one wedge surface (14; 14', 14") ascending against the direction of rotation (13), with which the bag sections (2', 2") at the open end region (9) of the tubular bag body (2) can be splayed apart during its transport on the transport device (3), in order to form the bottom opening (8) between the bag sections (2', 2") at the open end region (9) of the tubular bag body (2), and that the wedge elements (12; 12', 12", 12''') of successive splaying elements (10) have different wedge heights (h) increasing in the transport direction (5) of the tubular bag body (2).
2. The device according to claim 1, characterised in that the wedge element (12) comprises two wedge surfaces diverging from one another in the transport direction (5), preferably an upper wedge surface (14') and a lower wedge surface (14"), wherein the upper wedge surface (14') and the lower wedge surface (14") are preferably each disposed at an acute angle to the supporting surface (4) for the tubular bag body (2) on the transport device (3).
3. The device according to claim 1 or 2, characterised in that the splaying elements (10) comprise wedge elements (12; 12', 12", 12''') overlapping during rotation in the transport direction (5) of the tubular bag body (2), wherein a - in the transport direction - preceding wedge element (12; 12', 12") comprises a cutout (18) for the passage of a - in the transport direction (5) - following wedge element (12; 12", 12''').
4. The device according to claim 3, characterised in that precisely three splaying elements (10) are provided, which comprise wedge elements (12; 12', 12", 12''') overlapping during rotation in the transport direction (5) for introduction between the bag sections (2', 2") at the open end region (9) of the tubular bag body (2).
5. The device according to any one of claims 1 to 4, characterised in that a wedge element (12; 12', 12", 12''') comprises, at a rear end region as related to the direction of rotation (13), a holding section (19; 19', 19") for holding a rear region (20) of the tubular bag body (2), as related to the transport direction (5), during the introduction of the wedge surface (14) of the - in the transport direction (5) - following wedge element (12; 12'', 12''') into a front region (21) of the tubular bag body (2).
6. The device according to claim 5, characterised in that the holding section (19; 19', 19") of the wedge element (12; 12', 12", 12''') comprises a leading edge (22), which is disposed essentially at the same height as the rear end of the wedge surface (14; 14', 14"), as viewed in the direction of rotation (13).
7. The device according to claim 5 or 6, characterised in that the wedge element (12; 12', 12'', 12''') comprises the cutout (18) for the passage of the - in the transport direction (5) - following wedge element (12; 12", 12''') between the wedge surface (14; 14', 14") and the holding section (19; 19', 19").
8. The device according to any one of claims 1 to 7, characterised in that the wedge element (12; 12', 12", 12''') is curved in the form of an arc, in particular in the form of an arc of circle, in the direction of rotation (13).
9. The device according to any one of claims 1 to 8, characterised in that the wedge element (12; 12', 12", 12''') is connected to a shaft element (15), which is coupled to a drive and the rotary axis (11) of the shaft element is preferably disposed essentially perpendicular to the supporting surface (4) for the bag body (2) on the transport device (3).
10. The device according to any one of claims 1 to 9, characterised in that the wedge element (12; 12', 12", 12''') comprises at least one plate part (16; 16', 16"), which is preferably disposed essentially perpendicular to the supporting surface (4) for the bag body (2) on the transport device (3) and which forms a wedge surface (14; 14', 14") at an end face, wherein the wedge element (12; 12', 12'', 12''') preferably comprises at least one disc part (17) which is preferably disposed essentially parallel to the supporting surface (4) for the bag body (2) on the transport device (3) and which is connected at the outer edge region to the plate part (16) comprising the wedge surface (14, 14', 14").
11. The device according to any one of claims 1 to 10, characterised in that the opening device (7) comprises a preliminary opening station (23), with which the bag sections (2', 2") at the open end region (9) of the tubular bag body (2) can be transferred from a state lying flat one upon the other into a state spaced apart from one another.
12. The device according to claim 11, characterised in that the preliminary opening station (23) comprises at least one guide element (24, 25) with a guide surface (24', 25') inclined towards the transport direction (5) for one of the bag sections (2', 2") at the open end region (9) of the tubular bag body (2), wherein the guide surface (24', 25') is connected to a suction element (26) for sucking the bag section (2', 2") against the guide surface (24', 25'), wherein a drive element (24", 24''') is preferably provided for driving the guide element (24, 25) with the guide surface (24', 25'), wherein the guide element (24, 25) preferably comprises a guide belt, in particular an endless belt, connected to the drive element (24", 24'''), on which belt the guide surface (24', 25') is formed for one of the bag sections (2', 2") at the open end region (9) of the tubular bag body (2).
13. The device according to claim 12, characterised in that the preliminary opening station (23) comprises two guide elements (24, 25) with - in the transport direction (5) - diverging guide surfaces (24', 25') for the bag sections (2', 2") at the open end region (9) of the tubular bag body (2).
14. The device according to claim 12 or 13, characterised in that the suction element (26) comprises at least one suction opening (26') provided on the guide surface (24', 25') for the purpose of sucking one of the bag sections (2', 2"), wherein the preliminary opening station (23) preferably comprises at least one vacuum generation 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).
15. A method for forming a bottom opening (8) between bag sections (2', 2") at the open end region (9) of a tubular bag body (2), wherein the bag body (2) is transported in a transport direction (5) transverse to its longitudinal extension (2a) and, during transport, a splaying element (10) rotating about a rotary axis (11) is introduced between the bag sections (2', 2") at the open end region (9) of the tubular bag body (2), characterised in that the opening device (7) comprises at least two splaying elements (10) following one another in the transport direction (5) of the tubular bag body (2), wherein each rotatable splaying element (10) comprises a wedge element (12; 12', 12'', 12''') with at least one wedge surface (14; 14', 14") ascending against the direction of rotation (13), wherein the wedge elements (12; 12', 12", 12''') of successive splaying elements (10) have different wedge heights (h) increasing in the transport direction (5) of the tubular bag body (2), wherein the bag sections (2', 2") at the open end region (9) of the tubular bag body (2) are splayed apart during its transport on the transport device (3) by the wedge surfaces (14; 14', 14'') of the wedge elements (12; 12', 12'', 12''') in order to form the bottom opening (8) between the bag sections (2', 2") at the open end region (9) of the tubular bag body (2).

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