Title of Invention

A TUBULAR BAG MACHINE

Abstract

(57) Abstract: A tubular bag machine (10) for forming bag packs (1) has a tube-forming device (17)comprising a forming shoulder (18) and a forming tube (19) connected thereto.. in order to make it possible for such a tular bag machine (10) to form bag packs (1) with two longitudinal seems (11,12) and two transverse seems (13,14) from a singal packaging-material web (15) the forming tube(19) has two interconnected section (24,25).one section (24) ,which is connectd to the forming tube (19) is inclined by an angles (a)with respect to the incoming packing-material web (15) in additional element (28) for forming one longitudinal seems(11) is connected (28) the forming tube (19)the tube forming device (17) interacts with two longitudinal-sems-sealing devices (33) 34)which are arranged opposite one and another ,and one transverse-seam-sealing device(41). • PRICE: THIRTY RUPEES

Full Text

R. 29497 23.10.95 Vt/Mg ROBERT BOSCH GMBH, 70442 Stuttgart Tubular bag machine Prior art The invention is based on a tubular bag machine according to the preamble of Claim 1. Tubular bag machines for producing so-called 4-sided bag packs are already known. These bag packs have two sealed longitu¬dinal seams and two sealed transverse seams. For this purpose, the known tubular bag machines process two heat-sealable packing-material webs which are positioned congruently one above the other, and on which sealing devices which are arranged to the aide of the packaging-material webs form the two longitudinal seams. The flexible tube which is produced in this way is then fed to a transverse-seam-sealing device for the formation of the two transverse seams. Furthermore, vertical tubular bag machines having a flexible-tube-forming device comprising a forming shoulder and a forming tube are known. However, the production of the abovementioned 4-sided bag packs by means of such tubular bag machines using a single packaging-material web has not been possible hitherto. Advantages of the invention In contrast, the inventive tubular bag machine with the characterizing features of Claim 1 has the advantage that it is possible to produce 4-sided bag packs with two longitudinal seams and two transverse seams using a single packaging-material web by means of tubular bag machines which have a forming shoulder and a forming tube. This is achieved according to the invention, by a single-part, angled-off forming tube and a wedge-shaped element. By means of these two elements, it is possible to form the second longitudinal seam from part of the flexible-tube wall without stressing, which would otherwise impair the shape or functional capacity of the bag packs, being introduced in the flexible tube. Further advantages and advantageous developments of the tubular bag machine according to the invention can be gathered from the subclaims and the description. Two guides which are arranged on both sides of the extension element make it possible to achieve better forming of the longitudinal seam and more precise feeding of the longitudinal scam to the downstream longitudinal-seam-sealing device. The width of the longitudinal seam can be adjusted in a simple manner by means of a cutting device which is connected to the longitudinal-seam-sealing device. Accordingly the present invention provides a tubular bag machine for producing bag packs with two sealed transverse seams and two sealed longitudinal seams from a heat-sealable packaging-material web, having a device for forming a flexible tube, a device for conveying the flexible tube, and a transverse-seam-sealing device and two longitudinal-seam-sealing devices, characterized in that the device for forming the flexible tube comprises a forming tube and a forming shoulder connected thereto, in that the forming tube has two sections each with an axis of symmetry, the axis of symmetry of the first section, which is connected to the forming shoulder, being inclined by an angle (a) with respect to the axis of symmetry of the second section, the angle (a) being oriented in the direction of the incoming packaging-material web, in that a wedge-shaped element for fonning one longitudinal seam from a single-piece packaging-material-web region is connected to the first section of the forming tube, in that the element is arranged within a slot formed in the forming shoulder, and in that the height (H) of the element increases towards the second section of the forming tube. An exemplary embodiment of the invention is explained in more detail in the following description and is illustrated in the drawing, in which Figure 1 shows a perspective view of a tubular bag machine. Figure 2 shows a perspective view of part of the tubular bag machine according to Figure 1, and Figure 3 shows a simplified side view of the tubular bag machine according to Figure 1. With reference to the accompanying drawings in which The tubular bag machine 10 illustrated in Figure I serves for producing bag packs 1 with two longitudinal seams 11, 12 and two transverse seams 13, 14 from a heat-sealable packaging-material web 15. For this purpose, the tubular bag machine 10 has a flexible-tube-forming device 17 which comprises a forming shoulder 18 and a forming tube 19 connected thereto. By means of the flexible-tube-forming device 17, the endless packaging-material web 15 is preformed into a flexible tube 20. Arranged on the forming tube 19 is a device 21 with two preferably vaccum-assisted conveying belts 22,23 for conveying the flexible tube 20. The cylindrical forming tube 19 has two sections ■ 24, 25 which have equal external diameters and are connected to one another in a flush manner, offset portions or edges being avoided in the process. The axis of synimetry 26 of the first section 24, which is con¬nected to the forming shoulder 18, is inclined by an angle a with respect to the axis of synmetry 27 of the second section 25, the angle a being oriented in the direction of the incoming packaging-material web 15. Fastened on the first section 24 of the forming tube 19, on the side of the incoming packaging-material web 15, is a wedge-like element 28 which is in the form of a plate, projects perpendicularly from the first section 24 and increases constantly in width B in the direction of the second section 25. The element 28 overlaps the entire region in which the forming shoulder 18 is connected to the forming tube 19, the forming shoulder 18 having, in the region of the element 28, a slot 30 which is at least somewhat wider than the element 28, with the result that part of the flexible-tube wall can be guided through between the side surfaces of the element 28 and the slot 30. In the second section 25, the element 26 continues in a rectangular extension element 2 9 of constant width, the height of which corresponds to the maximum width B (max) of the element 28. Arranged on both sides of the extension element 29 are two guide angles 31 which are intended for the flexible tube 20 and whose directing surfaces 32 extend parallel to, and at a short distance from, the extension element 29. Advantageously, the guide angles 31 are even designed so as to be extended into the region of the element 28. located level with the conveying belts 22, 23 are two diametrically opposite sealing-jaw pairs 33, 34 for the formation of the longitudinal seams 11, 12. In this arrangement, one sealing-jaw pair 33 is in alignment with the element 28 and the extension element 29. Each sealing-jaw pair 33, 34 has two heatable sealing jaws 35, 36; 37, 38 which can be displaced horizontally with respect to one another. Arranged on the sealing-jaw pair 33 assigned to the longitudinal seam 11, on the side located opposite the forming tube 19, is a cutting device 39, illustrated only in Figure 3, for severing a section of the longitudinal seam 11 which projects beyond the sealing jaws 35, 36. The sealing-jaw pairs 33, 34 are adjoined, in an aligned manner, in the conveying direction of the flexible tube 20 in each case by one longitudinal-seam-cooling device 40 for each longitudinal seam 11, 12. A transverse-seam-sealing device 41 is arranged beneath the forming tube 19, which terminates in a snout (not shown). The transverse-seam-sealing device 41 has two transverse-seam jaws 42, 43 which can be displaced horizontally with respect to one another and have integrated cutting devices for severing the bag packs 1 from the flexible tube 20. The above-described tubular bag machine 10 operates as follows: the packaging-material web 15, which is preferably supplied in the form of a roll, is fed continuously or cyclically to the flexible-tube-forming device 17 by means of the conveying belts 22, 23. The packaging-material web 15 is then preformed into the flexible tube 20 by the forming shoulder 18. One longi¬tudinal seam 12 is formed in a known maimer by the two opposite longitudinal borders of the packaging-material web 15. The other longitudinal seam 11 is formed by the element 28 which is integrally formed on the first section 24 of the forming tube 19. This takes place by a section of the flexible-tube wall being guided through the slot 30 in the forming shoulder 18 and being posi¬tioned against the side surfaces of the element 28. This positioning is made possible in that, by means of the first section 24 which is inclined by the angle or with respect to the second section 25, the material of the packaging-material web 15 which is necessary for forming the longitudinal seam 11 is guided in the direction of the element 28 without stressing occurring within the flexible tube 20 as a result. The longitudinal seam 11 is thus formed without any stressing. It follows from what has just been outlined above that the size of the angle a depends primarily on the width of the longitudinal seam 11 or on the height H of the element 28. This means that the higher the element 28, and thus the width of the longitudinal seam 11, is, the greater is the angle a which has to be selected. The operation of forming the longitudinal seam 11 is assisted by the two guide angles 31, which also ensure, in particular, that the longi¬tudinal seam 11 which has been formed is fed to the sealing-jaw pair 33 with opposite flexible-tube walls located closely together, as a result of which the longitudinal-sealing operation is made easier. Once the two longitudinal seams 11, 12 have been formed as described above, they pass into the region of the two sealing-jaw pairs 33, 34, which seal the longi¬tudinal seams 11, 12 by means of heat and pressure. If one longitudinal seam 11 is wider than the sealing jaws 35, 36 of the sealing-jaw pair 33, then the projecting, non-sealed region of the longitudinal seam 11 is subsequently severed by means of the cutting device 39. The two sealed longitudinal seams 11, 12 are then cooled by the two longitudinal-seam-cooling devices 40. This thus achieves the seam strength of the longitudinal seams 11, 12 which is necessary for the subsequent filling operation, which takes place, for example, by way of filling material being fed through the forming tube 19. Finally, individual bag packs 1 are severed in a known manner from the resulting flexible tube 20 by means of the transverse-seam-sealing device 41, which simultane¬ously forms the two transverse seams 13, 14. WE ClAIM: 1. A tubular bag machine (10) for producing bag packs (I) with two sealed transverse seams (13, 14) and two sealed longitudinal seams (11,12) from a heat-sealable packaging-material web (15), having a device (17) for forming a flexible tube (20), a device (21) for conveying the flexible tube (20), and a transverse-seam-sealing device (41) and two longitudinal-seam-sealing devices (33, 34), characterized in that the device (17) for forming the flexible tube (20) comprises a forming tube (19) and a forming shoulder (18) connected thereto, in that the forming tube (19) has two sections (24, 25) each with an axis of symmetry (26, 27), the axis of symmetry (26) of the first section (24), which is connected to the forming shoulder (18), being inclined by an angle (a) with respect to the axis of symmetry (27) of the second section (25), the angle (a) being oriented in the direction of the incoming packaging-material web (15), in that a wedge-shaped element (28) for forming one longitudinal seam (11) from a single-piece packaging-material-web region is connected to the first section (24) of the forming tube (19), in that the element (28) is arranged within a slot (30) formed in the forming shoulder (18), and in that the height (H) of the element (28) increasestowards the second section (25) of the forming tube (19). 2. The tubular bag machine according to claim 1, wherein the element (28) is arranged over the entire area in which the forming shoulder (18) and the forming tube (19) overlap. 3. The tubular bag machine according to claim 1 or 2, wherein, in the region of the second section (25) of the forming tube (19), the element (28) is designed so as to be extended by a rectangular extension clement (29). 4. The tubular bag machine according to claim 3, wherein, in the region of the extension element (29), two guides (31) arranged on both sides of the extension element (29) are provided for one longitudinal seam (11). 5. The tubular bag machine according to claim 4, wherein the guides (31) are designed so as to be extended into the region of the element (28) for forming one longitudinal seam (11). 6. The tubular bag machine according to any one of claims 1 to 5, wherein, for forming one longitudinal seam (11), the longitudinal-seam-sealing device (33) is arranged so as to be in alignment with the extension elements (29) on the second section (25) of the forming tube (19). 7. THE tubular bag machine according to any one of claims 1 to 6, wherein a cutting device (39) for severing one longitudinal seam (11) to a specific width is operatively connected to one longitudinal-seam-sealing device (33). 8. A tubular bag machine substantially as herein described with reference to the accompanying drawings.

Documents:

1421-mas-1996 abstract.pdf

1421-mas-1996 claims.pdf

1421-mas-1996 correspondence-others.pdf

1421-mas-1996 correspondence-po.pdf

1421-mas-1996 description (complete).pdf

1421-mas-1996 drawings.pdf

1421-mas-1996 form-1.pdf

1421-mas-1996 form-26.pdf

1421-mas-1996 form-4.pdf

1421-mas-1996 form-9.pdf

1421-mas-1996 petition.pdf