Title of Invention

TUBULAR BAG MACHINE

Abstract

The present invention relates to a tubular bag machine (10) for producing bag packs (22) of rectangular cross-section and a bottom closure with side folds drawn in in the shape of a V from a web of packaging material (14), having a shaping tube (12), around which the web of packaging material (14) is shaped into a flexible tube (16) and which has at a run-in cross-section (31) a circular surface area and at a run-out cross-section (33) a rectangular surface area, with in each case the same peripheral extent, having a folding device (25), located after the run-out cross-section (33) of the shaping tube (12) for drawing in side folds, at least in the bottom region of the end section of the flexible tube, and having a transverse-seam-sealing and separating device (21) for forming closure seams in the region of the folding of the flexible tube (16) and detaching a bag pack (22) from the end section of the flexible tube, characterized in that between the circular run-in-cross-section (31) and the rectangular run-out cross-section (33) of the shaping tube (12 an additional intermediate cross-section (32) of the same peripheral extent as the two cross-section (31, 33) is provided to convey the flexible tube (16) along surface lines (la-lb-lc to 8a-8b-8c) of virtually the same length when passing over from the circular cross-section (31) to the rectangular cross-section (33). PRICE: THIRTY RUPEES

Full Text

Prior Art The Invention is based on a tubular bag machine according to the precharacterizing clause of Claim 1. In the case o£ such a tubular bag machine, a web of packaging material is conveyed over a hollow shaping tube and shaped into a flexible tube. The cross-section of the shaping the merges in the conveying direction of the flexible tube continuously from a circular cross-section into a rectangular cross-section at the run-out end, on the underside of which the end section of the flexible tube is folded by means of a folding device to form a folded standing base or block base with side folds drawn-in in the shape of a V. It is disadvantageous in this case that, at the transition from the circular cross-section to the rectangular cross-section, owing to surface lines of linequal length of the shaping t\ibe over its peripheral extent, the flexible tube is compressed to different degrees in the longitudinal direction. Particu¬larly in the case of less flexible packaging materials and packaging materials which have a high friction coefficient, such as for example paper, this therefore leads to a formation of waves and folds, which may hinder transporting of the sheet. Depending on the packaging material and the extent of the wave and fold formation, the appearance and the leaktightness of the bag packs produced from the flexible tube may even be impaired. Therefore, a tubular bag machine with which packaging materials having high friction coefficients and packaging materials which tend towards wave and fold formation, such as paper or the like, can be processed without folds into bag packs is desirable. Advantages of the invention The tubular bag machine according to the inven¬tion with the characterizing features of Claim 1 has in comparison the advantage that the differences in length of the surface lines of the shaping tube are minimized and the wave and fold formation of the packaging material is consequently reduced. Further advantages and advantageous developments of the invention emerge from the subclaims and the description. Particularly low wave and fold formation is achieved if the intermediate cross-section is of a square design, the shaping tube in this case being particularly simple to produce. To be able to prevent clogging of the shaping tube with products, the lower regions of the side walls of the shaping tvibe may be provided with clearances, or else the solid side walls are replaced by correspondingly shaped bars. Accordingly, the present invention provides a tubular bag machine for producing bag packs of rectangular cross-section and a bottom closure with side folds drawn in in the shape of a V from a web of packaging'material, having a shaping tube, around which the web of packaging material is shaped into a flexible tube and which has at a run-in cross-section a circular surface area and at a run-out cross-section a rectangular surface area, with in each case the same peripheral extent, having a folding device, located after the run-out cross-section of the shapmg tube for drawing in side folds, at least in the bottom region of the end section of the flexible tube, and having a transverse-seam-sealing and separating device for forming closure seams in the region of the folding of the flexible tube and detaching a bag pack from the end section of the flexible tube, characterized in that between the circular run-in CTOss-section and the rectangular run-out cross-section of the shaping tube an additional intermediate cross-section of the same peripheral extent as the two cross-section is provided to convey the flexible tube along surface lines of virtually the same length when passing over from the circular cross-section to the rectangular cross-section. An exemplary embodiment of the invention is represented in the drawing and is explained in more tubular bag machine in simplified form in front view. Fig. 2 shows a simplified longitudinal view of the lower part of a shaping tube. Fig. 3 shows a side view of the shaping tube according to Fig. 2, Fig. 4 shows a per¬spective view of the shaping tube according to Fig. 3' in diagrammatic form and Fig. 5 shows a plan view of the lower part of the shaping tube. Description of the exemplary embodiment A tubular bag machine 10 has a shaping shoulder 11 and a round, substantially hollow-cylindrical shaping tube 12 and also a longitudinal-seam-sealing device 13, with which a web 14 of packaging material is shaped into a flexible tube 16 in a known way. On both sides of the shaping tube 12, at the level of the longitudinal-seam-sealina device 13. there is assicmed a take-off device in the form of two, for example vacuum-assisted, conveyor belts 18 for the flexible tube 16. In the shaping tube 12 there concentrically extends a filling tube 19 for the filling product. Below the shaping tribe 12 there is a combined transverse-seaun-sealing and separating device 21 for sealing and detaching bag packs 22 from the flexible tube 16. Furthermore, above and below the transverse-seam- sealing and separating device 21 there is arranged a folding device 25 with side folders 26 for folding side folds drawn in in the shape of a V in the bottom closure and, if appropriate, in the top closure of the bag pack 22 and for forming a standing base or block base. In order to create a continuous transition from the circular cross-section of the shaping tube upper part to its run-out end, forming the standing base or block base, the upper part of the shaping tube 12 is adjoined by a lower part 27 having two sections 28, 29. The first section 28 has a circular run-in cross-section 31, which merges into a square intermediate cross-section 32 at a distance m. The second section 29 finally merges from the square intermediate cross-section 32 into an intended rectangular run-out cross-section 33, which at the same time forms the rvin-out end of the shaping tube 12. The run-out cross-section 33 is located at a distance M from the run-in cross-section 31. All the cross-sections 31, 32, 33 of the shaping tvibe 12 are arranged parallel to one another and their centres of gravity Sk, Sq and Sx lie on the axis of symmetry 34 of the shaping tribe 12. Likewise, the peripheral extents of the cross-sections 31, 32 and 33 are all identical. The first section 28 of the lower part 27 of the shaping tube 12 is composed, for example, of eight interconnected sheet-metal parts 36 to 43. In this arrangement, a triangular planar part 36 to 3 9 is in each case adjoined by a convex part 40 to 43, and vice-versa, so that as continuous a transition as possible on the circular run-in cross-section 31 to the square intermedi¬ate cross-section 32 is achieved. The second section 29 is composed of four respectively trapezoidal parts 44 to 47, whereby a continuous transition from the square intermediate cross-section 32 to the rectangular run-out cross-section 33 is likewise achieved. The two sections 28, 29 thus produced are, for example, welded to one another in the transverse direction. In the production of the sections 28, 29, it must always be ensured that no sharp edges or corners which could damage the flexible tube 16 when passing over from one cross-section to the other are produced. As a modification of the method of production presented above, the two sections 28, 29 can, for example, also be produced by developments of the two sections 28, 29. If the sections 28, 29 consist of a material other than sheet metal, for example of plastic, it is also conceivable to produce the sections 28, 29 from a single part. The distance m of the square intermediate cross-section 32 from the round run-in cross-section 31 results from the following considerations (Pig. 4): At the transition from the round run-in cross-section 31 to the rectangular run-out cross-section 33, the points la to 4a of the peripheral extent of the round run-in cross-section 31 are taken along the surface lines of the sections 28, 2 9 into the corresponding corner points Ic to 4c of the rectangular run-out cross-section 33. If all the points on the peripheral extent of the round run-in cross-section 31 and their corresponding points on the outer peripheral extent of the rectangular run-out cross-section 33 are considered, it is evident for geometrical reasons that the surface lines la-lc to 8a-8c are of different lengths, as becomes particularly clear from Fig. 5. This results from the fact that the distances to be covered horizontally by the surface lines la-lc to 8a-8c are of different lengths. The differences in length of the surface lines la-lc to 4a-4c in comparison with the surface lines 5a-5c to 8a-8c have the effect that transporting of the packaging material is greatly hin¬dered, in particular in the case of a packaging material having a high friction coefficient, or a less flexible packaging material, such as for example paper. Further- more, wave and fold formation may occur, and even visual or functional disadvantages of the bag packs produced from the packaging material may be the consequence. The square intermediate cross-section 32 has the least possible horizontal deviation between the round run-in cross-section 31 and the rectangular run-out cross-section 33. The relative deviation becomes all the smaller the greater the distance is between the rovind run-in cross-section 31 and the intermediate cross-section 32. The surface lines Ib-lc to 8b-8c between the intermediate cross-section 32 and the rectangular run-out cross-section 33 are always of the Seune length. At the transition from the intermediate cross-section 32 to the run-out cross-section 33 there is produced in the surface an angle a, which becomes all the greater the smaller the distance is between the intermediate cross-section 32 and the run-out cross-section 33. Too great an angle a has the effect, however, of increasing the frictional resist¬ance of the packaging material. Therefore, the aim is to find a compromise with respect to the length of the sections 28, 29 to the extent that, with a given overall length M, the distance between the intermediate cross-section 32 and the run-out cross-section 33 is not too small. Furthermore, the format of the bags 22, the length/width ratio of the run-out cross-section 33 and the filling product must be taken into consideration in the choice of the distance between the cross-sections 32 and 33. Depending on the overall length M of the sections 28, 29, it may, however, be necessary to optimize the position of the intermediate cross-section 32 to the extent that all the surface lines la-lb-lc to 8a-8b-8c are of the same length, because in the case of the arrangement of the intermediate cross-section 32 just proposed the surface lines 5a-5b-5c to 8a-8b-8c are slightly longer than the surface lines la-lb-lc to 4a-4b-4c. This means that the optimum distance m" is greater or smaller than the distance m by a certain amount, that is to sav the oackaaina material is addi- tionally also stretched slightly along the surface lines la-lb-lc to 4a-4b-4c. This setting of the distance m" does, however, presuppose a packaging material which is flexible to a certain degree. In order not to hinder product flow, it is conceivable to form on the parts 3 6 to 47 of the sections 28, 29, in particular on the trapezoidally designed parts 44 to 47, clearances which prevent clogging of the product flow cross-section. Instead of parts 36 to 47 preferably produced from sheet metal, " -bent bars, which are preferably round and have a smooth surface as possible, may also be used for producing the sections 28, 29, the said bars being arranged at least in the region of the surface lines la-lb-lc to 8a-8b»8c. Embodiments of the invention are not only restricted to a shaping tube 12 which permits a transition from a round cross-section to a rectangular cross-section. Equally possible is also a transition from a rounded-off rec¬tangular cross-section to a sharp-corner rectangular cross-section by means of an intermediate cross-section having a different length/width ratio. What is essential for the invention is that the different lengths of the surface lines on the peripheral extent of the packaging material are minimized at the transition from the one cross-section to the other cross-section by an intermediate cross-section. WE CLAIM: A tubular bag machine (10) for producing bag packs (22) of rectangular cross-section and a bottom closure with side folds drawn in in the shape of a V from a web of packaging material (14), having a shaping tube (12), around which the web of packaging material (14) is shaped into a flexible tube (16) and which has at a run-in cross-section (31) a circular surface area and at a run-out cross-section (33) a rectangular surface area, with in each case the same peripheral extent, having a folding device (25), located after the run-out cross-section (33) of the shaping tube (12) for drawing in side folds, at least in the bottom region of the end section of the flexible tube, and having a transverse-seam-sealing and separating device (21) for forming closure seams in the region of the folding of the flexible tube (16) and detaching a bag pack (22) from the end section of the flexible tube, characterized in that between the circular run-in cross-section (31) and the rectangular run-out cross-section (33) of the shaping tube (12) an additional intermediate cross-section (32) of the same peripheral extent as the two cross-section (31, 33) is provided to convey the flexible tube (16) along surface lines (la-lb-lc to 8a-8b-8c) of virtually the same length when passing over from the circular cross-section (31) to the rectangular cross-section (33). The tubular bag machine according to claim 1, wherein the intermediate cross-section (32) lias with respect to its surface-area centre of gravity (Sq) two maximum extents (lb to 4b) and two minimal extents (5b to 8b). The tubular bag machine according to one of claims 1 and 2, wherein the intermediate cross-section (32) is of a square design. The tubular bag machine according to one of claims 1 and 2, wherein the intermediate cross-section (32) is of a rectangular design, with a different length/'width ratio than the run-out cross-section (33) of the shaping tube (12). The tubular bag machine according to one of claims 1 to 4, wherein the shaping tube (12) has a lower part (27) with two sections (28,29), which have clearance at least in the region of the run-out cross-section (33) of the shaping tube (12). the tubular bag machine according to claim 5, wherein the sections (28, 29) are replaced by bar-shaped elements, which are arranged at least in the region of the surface lines (la-lb-lc to 4a-4b-4c) of the shaping tube sections (28,29). A tubular bag machine substantially as herein described with reference to the accompanying drawings.

Documents:

1125-mas-95 others.pdf

1125-mas-95 abstract.jpg

1125-mas-95 abstract.pdf

1125-mas-95 claims.pdf

1125-mas-95 correspondence others.pdf

1125-mas-95 correspondence po.pdf

1125-mas-95 description (complete).pdf

1125-mas-95 drawings.pdf

1125-mas-95 form-1.pdf

1125-mas-95 form-26.pdf

1125-mas-95 form-4.pdf

1125-mas-95 form-9.pdf

1125-mas-95 petition.pdf