EP3148790B1 - 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 a Voröffnungsstation, with which the bag sections at the open end portion of the tubular bag body from a flat superimposed state are transferred to a spaced-apart state, wherein the opening means comprises at least one rotatable about an axis of rotation spreader, which in the rotation between the Sack sections can be inserted at the open end region of the tubular bag body, wherein the rotatable expansion element, a wedge element with at least one en Towing the direction of rotation has rising wedge surface, with which the bag sections at the open end portion of the tubular bag body during its transport on the transport means are spread apart to form the bottom opening between the bag sections at the open end portion of the tubular bag body.

Furthermore, the invention 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 in a transport direction transversely to its longitudinal extent and formed during transport, a bottom opening between the bag sections at the open end portion of the tubular bag body the bag sections are transferred at the open end region of the tubular bag body in a pre-opening station from a flat superimposed state to a spaced-apart state.

Systems for the production of sacks have long been known in the art. These plants include the provision of material hoses, either by generating tubular webs or joining the Longitudinal edges of flat material webs were obtained into a tubular structure, the cutting of the material hoses into tubular bag bodies of suitable length and the formation of a sack bottom by suitably opening, folding and closing an open 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 is spread apart evenly. In order to allow the penetration of the spreading between the tube layers, a conventional separating finger is provided in this embodiment.

In the device of US 5,279,095 A In the transporting direction immediately downstream of a cutting device, an opening device is arranged which consists of a pair of upper suction belts and a pair of lower suction belts. The suction belts are guided over pairs of deflection rollers. The bags are separated by the suction belts when they are picked up. Mutually facing strands of the two Saugbandpaare form an adjustable, acute angle of at most with each other.

On the other hand reveals the 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 by 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 a rotational axis 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 of the gear wheels caused by orbital motion of a pivoting movement.

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.

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 an apparatus and a method for forming a bottom opening, as mentioned above, with which or with which the disadvantages of the prior art are alleviated or eliminated. Accordingly, the invention is on the one hand to the goal to produce the bottom opening on the tubular bag body 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 13. Preferred embodiments are given in the dependent claims.

According to the invention, the pre-opening station has at least one guide element with a guide surface inclined for the transport direction for one of the sack sections at the open end region of the tubular sack body, the guide surface being connected to a suction element for sucking the sack 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 be transferred. This design is characterized by high precision and reliability. Furthermore, malfunctions can be prevented or reduced to a minimum. In addition, a high conveying speed can be achieved. Through the Voröffnungsstation the bottom opening can be released so far that the bottom opening, as will be described below, can be completed.

In order to allow an immediate transfer of the bag body from the Voröffnungsstation to the at least one expansion element, which is at least one guide element of Pre-opening station seen in the transport direction 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, a suction opening is preferably carried along 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 pre-opening station has two guide elements with guide surfaces diverging in the transport direction for the bag sections at the open end region of the tubular bag body. In a preferred embodiment, an upper guide element with an upper guide surface rising in the transport direction and a lower guide surface Guide element provided with a downwardly sloping in the transport direction lower guide surface. 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, the prior art in the transport direction after the suction belt further Voröffnungseinrichtungen, in particular a compressed air nozzle and counter-rotating suction box pairs, provided to allow the unfolding of the bag bottom. 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 the guide element forming endless belt has exactly two suction 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 intake openings preferably corresponds substantially to half the length (ie 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. As a result, the associated bag section is applied to the guide surface of the endless belt.

According to a particularly preferred embodiment, the opening device has at least one expansion element rotatable about an axis of rotation, which can be inserted at the rotation between the bag sections at the open end region of the tubular bag body, the rotatable expansion element having a wedge element with at least one wedge surface rising counter to the direction of rotation which the bag sections at the open end portion of the tubular bag body during its transport on the transport means are spread apart to the bottom opening between the bag sections at the open end portion of the tubular Form bag body. Depending on the design, (at least one), in particular also at both end regions of the tubular bag body (bottom) openings can be 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.

In order to allow the penetration of the expansion element into the open end region of the tubular bag body, the Voröffnungsstation is provided in the transport direction in front of the at least one expansion element, with which the bag sections at the open end portion of the tubular bag body from a flat superposed state in a spaced-apart state can be transferred , 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.

To complete the bottom opening after the pre-opening station, a wedge-shaped expansion element is preferably used in this embodiment whose wedge surface increases counter to the direction of rotation, ie 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 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 at the open end of the tubular Sack body are conveyed in a horizontal position through the opening device. 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. 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 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 with respect to the support surface for the tubular bag body arranged symmetrically on the conveyor. 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 form the bottom opening at the open end region of the tubular bag body with the required opening width, it is advantageous if 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, it is advantageous if 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.

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 overlapped during the orbital motion, with 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 rear end of the wedge surface viewed in the direction of rotation. 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.

The object underlying the invention is also achieved by a method of the type mentioned, in which at least one of the bag sections is transported in the Voröffnungsstation along a direction inclined to the transport direction guide surface, wherein the bag section is sucked to the guide surface.

• 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;
• Fig. 2 bis 7 schematisch Ansichten eines Teils der Öffnungseinrichtung gemäß Fig. 1a beim Ausbilden der Sacköffnung mittels keilförmigen Spreizelementen, 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 ;
• 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 Appendix 1 has a (not shown) separating device to separate the web into tubular bag bodies 2. The tubular bag body 2 consist of two stacked 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, the bag body 2 are successively on a substantially horizontal bearing 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'. As guide elements 24, 25 endless belts are provided in the embodiment shown, 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 each endless belt exactly two suction ports 26 'on (see. 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 negative pressure chamber 27 ', which adjacent to the Guide surface 24 ', 25' of the upper 24 and lower guide member 25 extends. 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 to a suction 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 to be 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 by means of finger elements 29 in a correct, rectangular position. 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 one in a horizontal plane flat superimposed 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 6 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. Viewed in the transport direction 5 mean wedge element 12 "and in Transport direction 5 seen rear wedge element 12 '"each have an upper plate member 16', which has the upper wedge surface 14 'at an upper end side, and a lower plate member 16", which has the lower wedge surface 14 "at a lower end face Plate elements 16, 16 ', 16 "are curved in a top view according to the direction of rotation 13 in a circular arc. In addition, the wedge elements 12 substantially in a horizontal plane extending disc 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 members 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 weiters apparent, the wedge element 12 has a rear end region with respect to the direction of rotation 13 Holding portions 19, with respect to the transport direction 5 rear portions 20 of the bag sections 2 ', 2''are held in the current opening state, while the wedge surface 14 of the following in the transport direction 5 wedge element 12 in front regions 21 of the bag sections 2', 2 '' 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 substantially at the same height as seen in the direction of rotation 13 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 assigned to the upper bag section 2 'and the lower bag section 2 "of the tubular bag body 2. As a result, the takeover of the tubular bag body 2 from the front wedge element 12 'to the middle wedge element 12 "can be made reliable., On the other hand, the central wedge element 12" has corresponding holding sections 19 "in the transport direction 5 in order to reliably transfer the bag body 2 to the transport direction 5 seen rear wedge element 12 '' 'to accomplish.

The terms "bottom" and "top" for the arrangement of various components, such as the wedge elements, are used in the present disclosure as an example of a preferred operating position, in which the bag sections 2 ', 2' 'at the open end portion 9 of the tubular bag body 2 in to be transported in a horizontal position. Of course, however, an embodiment may be provided 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. Device for forming a base opening (8) between bag portions (2', 2") at an open end region (9) of a tubular bag body (2), comprising a transport apparatus (3) for transporting the bag body (2) in a transport direction (5) transversely to its longitudinal extension (6), and comprising an opening apparatus (7) for forming the base opening (8) between the bag portions (2', 2") at the open end region (9) of the tubular bag body (2), the opening apparatus (7) having a pre-opening station (23), by means of which the bag portions (2', 2") at the open end region (9) of the tubular bag body (2) can be transferred from a flat state, in which they lie on top of one another, into a state in which they are spaced apart from one another, the opening apparatus (7) having at least one spreading element (10) which is rotatable about an axis of rotation (11) and can be inserted between the bag portions (2', 2") at the open end region (9) of the tubular bag body (2) during the rotation, the rotatable spreading element (10) having a wedge element (12; 12', 12", 12"') which comprises at least one wedge surface (14; 14', 14") that rises counter to the direction of rotation (13), by means of which surface the bag portions (2', 2") at the open end region (9) of the tubular bag body (2) can be spread apart from one another during the transportation of said bag body on the transport apparatus (3), in order to form the base opening (8) between the bag portions (2', 2") at the open end region (9) of the tubular bag body (2), characterised in that the pre-opening station (23) has at least one guide element (24, 25) comprising a guide surface (24', 25') for one of the bag portions (2', 2") at the open end region (9) of the tubular bag body (2), which surface is inclined towards the transport direction (5), the guide surface (24', 25') being connected to a suction element (26) for suctioning the bag portion (2', 2") onto the guide surface (24', 25'), the at least one guide element (24, 25) of the pre-opening station (23), seen in the transport direction (5), being arranged so as to overlap with the at least one spreading element (10).
2. Device according to claim 1, characterised in that a drive element (24", 24"') is provided for driving the guide element (24, 25) which comprises the guide surface (24', 25'), the guide element (24, 25) preferably having a guide belt which is connected to the drive element (24", 24"'), in particular having an endless belt, on which the guide surface (24', 25') for one of the bag portions (2', 2") at the open end region (9) of the tubular bag body (2) is formed.
3. Device according to either claim 1 or claim 2, characterised in that the pre-opening station (23) has two guide elements (24, 25) which have guide surfaces (24', 25') for the bag portions (2', 2") at the open end region (9) of the tubular bag body (2), which surfaces diverge from one another in the transport direction (5).
4. Device according to any of claims 1 to 3, characterised in that the suction element (26) has at least one suction opening (26') which is provided on the guide surface (24', 25') for suctioning one of the bag portions (2', 2"), preferably exactly one suction opening (26') being arranged on the guide surface (24', 25'), the endless belt which forms the guide element (24, 25) preferably having exactly two suction openings (26').
5. Device according to claim 4, characterised in that the pre-opening station (23) has at least one vacuum-generating unit (27) comprising a vacuum chamber (27') which is adjacent to the guide surface (24', 25') of the guide element (24, 25) that has the suction opening (26).
6. Device according to any of claims 1 to 5, characterised in that the wedge element (12) has two wedge surfaces which diverge in the transport direction (5), preferably an upper wedge surface (14') and a lower wedge surface (14"), the upper wedge surface (14') and the lower wedge surface (14") preferably each being arranged at an acute angle to the bearing surface (4) for the tubular bag body (2) on the transport apparatus (3).
7. Device according to any of claims 1 to 6, characterised in that the opening apparatus (7) has at least two spreading elements (10) which are successive in the transport direction (5) of the tubular bag body (2), the wedge elements (12; 12', 12", 12"') of successive spreading elements (10) preferably having different wedge heights (h) which increase in the transport direction (5) of the tubular bag body (2) and are preferably perpendicular to the bearing surface (4) for the tubular bag body (2) on the transport apparatus (3).
8. Device according to claim 7, characterised in that the spreading elements (10) have overlapping wedge elements (12; 12', 12", 12"') during the rotation in the transport direction (5) of the tubular bag body (2), a wedge element (12; 12', 12") which precedes in the transport direction having a recess (18) for the passage of a wedge element (12; 12", 12"') which follows in the transport direction (5), preferably exactly three spreading elements (10) being provided, which, during rotation in the transport direction (5), have overlapping wedge elements (12; 12', 12", 12"') for insertion between the bag portions (2', 2") at the open end region (9) of the tubular bag body (2).
9. Device according to any of claims 1 to 8, characterised in that a wedge element (12; 12', 12", 12'") has a holding portion (19; 19', 19") at a rear end region with respect to the direction of rotation (13), which portion is for holding a rear region (20) of the tubular bag body (2) with respect to the transport direction (5) when the wedge surface (14) of the wedge element (12; 12", 12"') which follows in the transport direction (5) is inserted into a frontal region (21) of the tubular bag body (2), the holding portion (19; 19', 19") of the wedge element (12; 12', 12", 12"') preferably having a leading edge (22) which is arranged substantially at the same height as the rear end of the wedge surface (14; 14', 14") seen in the direction of rotation (13), the wedge element (12; 12', 12", 12"') between the wedge surface (14; 14', 14") and the holding portion (19; 19', 19") preferably having the recess (18) for the passage of the wedge element (12; 12", 12"') which follows in the transport direction (5).
10. Device according to any of claims 1 to 9, characterised in that the wedge element (12; 12', 12", 12'") is curved in an arc, in particular a circular arc, in the direction of rotation (13).
11. Device according to any of claims 1 to 10, characterised in that the wedge element (12; 12', 12", 12"') is connected to a shaft element (15) coupled to a drive, the axis of rotation (11) of which shaft element is preferably arranged such that it is substantially perpendicular to the bearing surface (4) for the bag body (2) on the transport apparatus (3).
12. Device according to any of claims 1 to 11, characterised in that the wedge element (12; 12', 12", 12"') has at least one plate part (16; 16', 16") which is preferably arranged such that it is substantially perpendicular to the bearing surface (4) for the bag body (2) on the transport apparatus (3), which plate part forms a wedge surface (14; 14', 14") on one end face, the wedge element (12; 12', 12", 12"') preferably having at least one disc part (17) which is preferably arranged such that it is substantially parallel to the bearing surface (4) for the bag body (2) on the transport apparatus (3), which disc part is connected at the outer edge region to the plate part (16) which has the wedge surface (14, 14', 14").
13. Method for forming a base opening (8) between bag portions (2', 2") at the open end region (9) of a tubular bag body (2), the bag body (2) being transported in a transport direction (5) transversely to its longitudinal extension (2a) and a base opening (8) being formed between the bag portions (2', 2") at the open end region (9) of the tubular bag body (2) during the transportation, the bag portions (2', 2") at the open end region (9) of the tubular bag body (2) being transferred, in a pre-opening station (23), from a flat state, in which they lie on top of one another, into a state in which they are spaced apart from one another, before a spreading element (10) which rotates about an axis of rotation (11) is inserted between the bag portions (2', 2") at the open end region (9) of the tubular bag body (2), in order to form the base opening (8) between the bag portions (2', 2") at the open end region (9) of the tubular bag body (2), characterised in that at least one of the bag portions (2', 2") is transported in the pre-opening station (23) along a guide surface (24', 25') of at least one guide element (24, 25) that is inclined towards the transport direction (5), the bag portion (2', 2") being suctioned onto the guide surface (24', 25'), the at least one guide element (24, 25) of the pre-opening station (23), seen in the transport direction (5), being arranged so as to overlap with the at least one spreading element (10).
14. Method according to claim 13, characterised in that the bag body (2) is suctioned at exactly one suction opening (26') on the guide surface (24', 25') during transport through the pre-opening station (23).
15. Method according to either claim 13 or claim 14, characterised in that the guide surface (24', 25') for the bag body (2) is formed on an endless belt which has exactly two suction openings (26'), at most one of the suction openings (26') being arranged on the guide surface (24', 25') during rotation of the endless belt.

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