Process for manufacturing bags

Abstract

An apparatus for production of sacks from semi-finished sacks, preferably tube pieces, with which sacks of different format can be produced has at least one device for the folding of sack bottoms and at least one gluing station for the gluing of at least the bottom flaps of an opened bottom square of the sack bottoms. The gluing station has at least two application heads. Each application head has a glue application area, whose extent is variable in a spatial direction (y), and is movable relative to a bottom center line of the sacks. A maximum glue application area in the spatial direction (y) has a length that is shorter than a spacing (C) located on one side of a bottom center line between an outer edge of the bottom flap of the largest sack format gluable in the gluing station and the center line of the sack.

Claims

1. An apparatus for production of sacks from semi-finished sacks, with which sacks of different format can be produced, said apparatus comprising: at least one device that folds sack bottoms; and at least one gluing station that provides a glue to at least bottom flaps of an opened bottom square of the sack bottoms, the at least one gluing station applying glue tracks of different dimensions at least on the bottom flaps, and including at least two application heads each having a glue application area whose extent is variable in a spatial direction (y), which is orthogonal to a feed direction of the sack bottoms, and each of the at least two application heads being movable in the spatial direction (y) relative to a bottom center line of the sacks, the at least two movable application heads having a maximum application area, in the spatial direction (y), defined by for a smallest sack format gluable in the gluing station, a length of the application head maximum application area that is less than or equal to a spacing (D) located on one side of a bottom center line between an outer edge of the bottom flap of a largest sack format gluable in the gluing station and a crease line, the crease line being located, in the spatial direction (y), outward of the bottom center line of the bottom of the sack, and for the largest sack format gluable in the gluing station, a length of the application head maximum application area that is greater than or equal to a spacing (E) located on the one side of the bottom center line between the outer edge of the bottom flap of the largest sack format gluable in the gluing station and the crease line, the crease line being located, in the spatial direction (y), outward of the bottom center line of the bottom of the sack, with the at least two movable application heads each including (i) a plurality of first glue valves, each of the first glue valves each having two glue application openings, which together provide a first glue application area, and (ii) a single second glue valve disposed at one end of the movable application head, the second glue valve having only one glue application opening, which provides a second glue application area that is smaller than the first glue application area, the single second glue valve thereby being configured to provide in the crease line area of the sacks, increased resolution of glue application in the second glue application area relative to the resolution provided by the two glue application openings of the first glue application area.

2. The apparatus according to claim 1, wherein the length associated with the maximum application area is greater than or equal to half of the spacing (E).

3. The apparatus according to claim 1, wherein the at least two application heads each have glue outlet openings which are selectively supplied with glue through valves, in which a format of glue application is defined by selecting the valves that are to be open, and wherein the at least one edge of the maximum application area of the at least two application heads has more active valves that are activatable for the glue application than another area of an application area of the at least two application heads.

4. The apparatus according to claim 3, wherein the length associated with the maximum application area differs from the spacing (E) by a spacing (a) of two of the glue openings on the application heads.

5. The apparatus according to claim 3, wherein the length associated with the maximum application area differs from the spacing (E) by an active application area (a, b) of the glue valve.

6. The apparatus according to claim 1, wherein the semi-finished sacks are tube pieces.

7. The apparatus according to claim 1, wherein the increased resolution of glue application by the application head in the second glue application area is characterized by a more accurate adjustment of dimensions of the applied glue track.

8. A gluing station for providing a glue to at least bottom flaps of an opened bottom square of bottoms of sacks with glue tracks of different dimensions, said gluing station comprising: at least two application heads each having a glue application area whose extent is variable in a spatial direction (y), which is orthogonal to a feed direction of the sack bottoms, and each of the at least two application heads being movable in the spatial direction (y) relative to a bottom center line of the sacks, the at least two application heads having a maximum application area, in the spatial direction (y), defined by for a smallest sack format gluable in the gluing station, a length of the application head maximum application area that is less than or equal to a spacing (D) located on one side of a bottom center line between an outer edge of the bottom flap of a largest sack format gluable in the gluing station and a crease line, the crease line being located, in the spatial direction (y), outward of the bottom center line of the bottom of the sack, and for the largest sack format gluable in the gluing station, a length of the application head maximum application area that is greater than or equal to a spacing (E) located on the one side of the bottom center line between the outer edge of the bottom flap of the largest sack format gluable in the gluing station and the crease line, the crease line being located, in the spatial direction (y), outward of the bottom center line of the bottom of the sack, with the at least two movable application heads each including (i) a plurality of first glue valves, each of the first glue valves each having two glue application openings, which together provide a first glue application area, and (ii) a single second glue valve disposed at one end of the movable application head, the second glue valve having only one glue application opening, which provides a second glue application area that is smaller than the first glue application area, the single second glue valve thereby being configured to provide in the crease line area of the sacks, increased resolution of glue application in the second glue application area relative to the resolution provided by the two glue application openings of the first glue application area.

9. An apparatus for production of sacks from semi-finished sacks, with which sacks of different format can be produced, said apparatus comprising: at least one device that folds sack bottoms; and at least one gluing station that provides a glue to at least bottom flaps of an opened bottom square of the sack bottoms, the at least one gluing station (i) applying glue tracks of different dimensions at least on the bottom flaps, and (ii) including at least two application heads each having a glue application area whose extent is variable in a spatial direction (y), each being movable relative to a bottom center line of the sacks, and each having a plurality of glue valves each having associated therewith a plurality of glue openings, the at least two application heads having a maximum application area, in the spatial direction (y), defined by for a smallest sack format gluable in the gluing station, a length of the application head maximum application area that is less than or equal to a spacing (D) located on one side of a bottom center line between an outer edge of the bottom flap of a largest sack format gluable in the gluing station and a crease line, the crease line being located, in the spatial direction (y), outward of the bottom center line of the bottom of the sack, and for the largest sack format gluable in the gluing station, a length of the application head maximum application area that is greater than or equal to a spacing (E) located on the one side of the bottom center line between the outer edge of the bottom flap of the largest sack format gluable in the gluing station and the crease line, the crease line being located, in the spatial direction (y), outward of the center line of the bottom of the sack, and the at least two application heads each having at an end thereof a single glue valve having associated therewith a corresponding single glue opening, the single glue valve with the corresponding single glue opening thereby being configured to provide at the end of the application head, which services the crease line area of the sacks, an increased number of glue valves per unit length of the application head relative to the number of glue valves in a portion of the application head having the plurality of glue valves each having associated therewith a plurality of glue openings.

10. The apparatus according to claim 9, wherein the single glue valve and the corresponding single glue opening provide a reduced glue application area relative to each glue application area associated with the plurality of glue valves each having associated therewith the plurality of glue openings.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The individual figures show:

(2) FIG. 1 an individual application head provided for the gluing station in the bottom laying device according to the invention

(3) FIG. 2 a sketch of folded up bottom squares

(4) FIG. 3 sketch of folded up bottom squares that are guided to a gluing station

(5) FIG. 4 a sketch of sack transport in a bottom-laying apparatus

(6) FIG. 5 a sketch of the side of an application plate facing the sacks

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(7) Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modification within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

(8) FIG. 1 shows an application head 1, as used in a gluing station in the bottom-laying device according to the invention. This application head 1 consists of an application plate 2, on which valves 3 are mounted. The glue is fed to the application head 1 via glue feed line 4. Unglued slips 5 are fed to the glue station in direction x.

(9) One or a group of glue outlet openings is assigned to each valve 3 in the side of the application plate 2 facing the unglued slips 5. Glue flow to the glue outlet opening can be produced or interrupted by the assigned valve 3. In this way, it is possible to apply to the unglued slips 5 different glue tracks that run parallel to the feed direction x of the unglued slips 5. By regular opening and closing of valve 3, a regularly interrupted glue track 6 can be applied. Short glue tracks 7, interrupted glue tracks 8 and continuous glue tracks 9 can also be produced.

(10) If an unglued slip 5 is not situated beneath application head 1, glue flow through all valves 3 is interrupted, so as not to needlessly soil the gluing station. In order to be able to glue all areas of the unglued slips in direction y across the feed direction, the application head 1 is also movable in this direction. The application head 1 just described, however, can be used not only for gluing of slips 5, but is also suitable, because of variability of the glue tracks that can be produced, for glue application on the areas of the later sack bottom being glued. The last-mentioned type of application of such application heads is prominent in the present document.

(11) FIG. 2 shows the folded up bottom squares of the largest 30 and smallest 45 sack format, which can be glued with a gluing station.

(12) Both in the figures showing the folded up bottom squares and in the dimension details in the claims, it is initially assumed that the width of the bottom flaps corresponds to the width of the sack bottoms. The exceptions are mentioned.

(13) The contours of the largest sack format 30 are depicted with thicker lines than those of the smallest sack format 45. For the largest sack format 30, the outer edges of the bottom flaps 31, the crease lines 33 and the triangular pockets 36 are provided with reference numbers. Overall, however, all depicted contours are familiar in their significance to one skilled in the art, since cross-bottoms (for example, of cement sacks) have had these contours for decades in the folded up state.

(14) The same applies for contours of the smallest bottom square 45: the outer edges of the bottom flaps 32, the crease lines 34 and the triangular pockets 46 are again provided with reference numbers.

(15) The two depicted bottom squares 30 and 45 are aligned relative to each other, so that they have the same bottom center line 35. This corresponds to the transport situation of the sacks or sack components in most modern devices for production of sacks:

(16) The sacks in these devices, during part of sack production, are transported with the bottom square folded out. Sacks of different format, which are produced for processing different orders on the same device (offset in time), are often conveyed along the same bottom center line 35, in which the tube elements 47 are in the collapsed state.

(17) This transport situation is shown in FIG. 4 from a viewing angle represented by arrow 49: the tube in many modern bottom-laying devices is transported by any transport means 48, which hold the tube elements 47 (collapsed) and the bottom flaps 50 in this transport situation. Belts, rollers and plates are generally used as transport devices.

(18) Bars can be seen in FIG. 2 to the right next to the bottom square 30, 45. The first bar 37 symbolizes an application area, whose length corresponds to the spacing D between the crease line 34 of the smallest sack format and the outer edge of the largest sack format 31 on one side of the bottom center line 35. The length of the bar 38 corresponds to the spacing of crease line 34 of the smallest sack format, which can be produced in the corresponding gluing station or bottom layer and the outer edge 32 of the bottom flap of the smallest sack format.

(19) The spacing C is the spacing between the bottom center line 35 and the outer edge 31 of a bottom flap of the largest sack format 30. The spacing E is the spacing between the crease line 33 and the outer edge 31 of a bottom flap of the largest sack format (generally equal to the bottom width of the largest sack format). The total length of bar 51 is the entire area that can be covered in a gluing station on one side of the bottom center line during gluing with glue when the application heads have either a correspondingly wide application area or are movable in this area. The present document also proposes application heads having a maximum application area of smaller length than that of bar 51.

(20) Section 52 of bar 51 is the spacing between the bottom center line 35 and the crease line 34 of the smallest sack format 45.

(21) Section 39 of bar 51 corresponds to the length of the application area, which is to be saved when the application area of at least one application head 3, 40 has only a length that corresponds to the spacing between the crease line 33 and the outer edge 31 of the bottom flap of the largest sack format and not to the spacing between the outer edge 31 of the bottom flap of the largest sack format and the crease line 34 of the smallest sack format (area that must be provided with glue). As already mentioned above, the corresponding application head should also be movable relative to the application head or the other application heads or relative to the bottom center line in bottom-layers with a fixed bottom center line.

(22) The area between the crease line of the smallest possible sack format and the outer edge of the bottom flap of the largest possible sack area is the smallest area, on which glue application must be possible during production of the different possible sack formats (on one side of the bottom center line). The present document proposes advantageous devices for sack production of gluing, having application heads with application lengths that are shorter than this area.

(23) FIG. 3 again shows the bottom squares 30 and 45 depicted in FIG. 2. On the right edge of the figure, however, instead of the bar, the two application heads 40 with the two application plates 41 are shown. By means of arrows x and y, which represent the transport direction of the sacks and a spatial direction at right angles to it, it is symbolized that the sacks are transported into the work area of the application heads 40. Transport can occur in the manner sketched in FIG. 4. It should not be overlooked that at least one of the application heads should be movable in the y-direction, which is shown by the double arrow 44. Mobility of both heads offers advantages here. In a preferred variant, both application heads 40 should be movable relative to bottom center line 35.

(24) The application heads carry glue valves 42, 43. In this context, a glue valve is a component that can open and close a glue line. Glue valves 42, 43 of this type generally have one or more glue outlet openings 50, 51, which extrude glue onto the bag on the side facing away from the viewer.

(25) It is advantageous to provide at least one additional valve 43 in the end areas of the application areas of the application heads (FIG. 4). An additional valve 43 means that the number of valves active for gluing per length unit lies higher in this area than (for example) in the center of the application heads.

(26) With this expedient, the number of glue valves 42, 43 active per length unit (of the application area) can be increased in a certain length section of the application area of an application head 40. A smaller number of glue outlet lines and therefore a smaller length section b, in which the glue flow through the valve is critical, can then be assigned to the additional glue valves 43 (FIG. 5). If this occurs at least in an edge area of the application area of the application head 40, the resolution, with which different glue formats can be adjusted, can be increased from A (normal application area of a valve) to B (reduced application area of an additional valve).

(27) FIG. 5 again shows this circumstance. The side of an application plate 41 facing the sacks is shown here. It cannot be seen that two of the normal glue application openings 50 are assigned to a normal glue valve 42, i.e., receive their glue via this glue valve 42. An active application area of such a normal glue valve is therefore produced, as shown by the brackets A. It covers two normal glue application openings 50. An additional glue valve 43 (FIG. 3) is exclusively assigned to the additional glue application opening 51. The wiring of this additional glue valve 43 therefore only leads to a variation in length of the glue application area by B. B only covers a glue application opening and is therefore half as long as A when all glue application openings have the same spacing to each other.

(28) The depicted measures are advantageous in both end areas of the application area.

(29) The invention being thus described, it will be apparent that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be recognized by one skilled in the art are intended to be included within the scope of the following claims.

(30) TABLE-US-00001 List of reference numbers 1 Application head 2 Application plate 3 Valve 4 Glue feed line 5 Unglued slip 6 Regularly interrupted glue track 7 Short glue track 8 Interrupted glue track 9 Continuous glue track 30 Folded up bottom square of the largest sack format 31 Outer edge of the bottom flap of the largest sack format 32 Outer edge of the bottom flap of the smallest sack format 33 Crease line of the largest sack format 34 Crease line of the smallest sack format 35 Bottom center line 36 Triangular pocket of the largest sack format 37 Application area 1 38 Application area 2 39 Saved area 40 Application head 41 Application plate 42 Normal glue valve 43 Additional glue valve 44 Double-arrow (indicates mobility of the application head 40) 45 Folded up bottom square of the smallest sack format 46 Triangular pocket of the largest sack format 47 Tube element 48 Transport device 49 Arrows in the viewing direction of the view of FIG. 4 50 Normal glue outlet openings 51 Additional glue outlet openings 52 Spacing between bottom center line 35 and crease line 34 (smaller sack format) X Transport direction of sacks y Spatial direction (across transport direction x) A Application area of a normal glue valve 42 B Application area of an additional glue valve 43 C Spacing between 31 and 35 D Spacing between 31 and 34 E Spacing between 31 and 33