VACUUM CLEANER FILTER BAG WITH FILM IN THE REGION OF THE HOLDING PLATE

Abstract

The invention relates to a vacuum cleaner filter bag comprising a bag wall and a retaining plate (13) which is connected to the bag wall, wherein the bag wall comprises a film region in which a plastic film is arranged, wherein the film region comprises a first sub-region in which the bag wall is formed solely by the plastic film or in which the plastic film forms the outermost layer of the bag wall, wherein the film region comprises a second sub-region in which the plastic film is overlapped by a nonwoven fabric element (3), wherein the retaining plate (13) is connected, in particular welded, to the plastic film and the nonwoven fabric element (3), and wherein the nonwoven fabric element (3) has at least one part (11, 12) which is connected to the bag wall part surrounding the film region.

Claims

1. A vacuum cleaner filter bag comprising a bag wall and a retaining plate which is connected to the bag wall, wherein the bag wall comprises a film region in which a plastic film is arranged, wherein the film region comprises a first sub-region in which the bag wall is formed solely by the plastic film or in which the plastic film forms an outermost layer of the bag wall, wherein the film region comprises a second sub-region in which the plastic film is overlapped by a nonwoven fabric element, wherein the retaining plate is connected to the plastic film and the nonwoven fabric element, and wherein the nonwoven fabric element has at least one part which is connected to the bag wall part surrounding the film region.

2. The vacuum cleaner filter bag according to claim 1, wherein the plastic film is transparent or non-transparent.

3. The vacuum cleaner filter bag according to claim 1, wherein the nonwoven fabric element comprises a through-hole which is arranged concentrically with respect to a through-hole in the plastic film and a through-hole in the retaining plate.

4. The vacuum cleaner filter bag according to claim 3, wherein the nonwoven fabric element comprises an annular region that surrounds the through-hole and is connected to the bag wall part surrounding the film region via at least one connection piece, and wherein the retaining plate is connected to the nonwoven fabric element in the annular region.

5. The vacuum cleaner filter bag according to claim 4, wherein at least two connection pieces connect the annular region to the bag wall part surrounding the film region on opposing sides of the film region.

6. A method for producing a vacuum cleaner filter bag, the method comprising: punching at least one through-opening into a sheet of nonwoven fabric such that a region free of nonwoven fabric is formed in the sheet of nonwoven fabric and a nonwoven fabric element is formed between two opposing edge portions of the region free of nonwoven fabric, wherein the nonwoven fabric element is spaced apart from the opposing edge portions by a sub-region of the region free of nonwoven fabric; connecting a plastic film to the sheet of nonwoven fabric such that, when the sheet of nonwoven fabric is viewed in plan view, the plastic film completely overlaps with the region free of nonwoven fabric and the nonwoven fabric element; forming a through-hole in the plastic film and in the nonwoven fabric element; welding a retaining plate to the plastic film and the nonwoven fabric element.

7. The method according to claim 6, wherein the at least one through-opening include two through-openings, which are formed symmetrically with respect to an axis of symmetry that extends in the machine direction, and the two through-openings are punched such that the nonwoven fabric element remains between the two through-openings.

8. The method according to claim 6, wherein a region of the sheet of nonwoven fabric including the region free of nonwoven fabric and the nonwoven fabric element has a rectangular boundary.

9. The method according to claim 6, wherein the nonwoven fabric element comprises, before the through-hole is formed, a region in a shape of a disc and at least one connection piece, which connects the region in the shape of a disc to rest of the sheet of nonwoven fabric.

10. The method according to claim 9, wherein the region in the shape of a disc is annular and the retaining plate is connected to the annular region of the nonwoven fabric element.

11. The method according to claim 10, wherein the retaining plate comprises guides which are arranged in a region of the retaining plate surrounding a through-hole of the retaining plate, wherein a radial extension of the region of the retaining plate corresponds to that of the annular region of the nonwoven fabric element.

12. The method according to claim 6, wherein the retaining plate and the plastic film are arranged such that the nonwoven fabric element is located between the retaining plate and the plastic film after connection of the retaining plate.

13. The method according to claim 6 to, wherein the retaining plate and the plastic film are arranged such that the plastic film is located between the retaining plate and the nonwoven fabric element after connection of the retaining plate.

14. The method according to claim 6, wherein the region of the sheet of nonwoven fabric in which the at least one through-opening is to be formed is at least partially thermally compacted prior to punching of the at least one through-opening.

15. The method according to claim 6, wherein the plastic film is connected to the nonwoven fabric element and to a part of the sheet of nonwoven material surrounding the region free of nonwoven fabric.

16. The vacuum cleaner filter bag of claim 1, wherein the retaining plate is welded to the plastic film and the nonwoven fabric element.

17. The method of claim 8, wherein the rectangular boundary comprises a square boundary.

Description

[0059] Additional features and advantages of the invention will be explained below with reference to the exemplary figures, in which:

[0060] FIG. 1 shows an illustration of a first step of an exemplary method for producing a vacuum cleaner filter bag;

[0061] FIG. 2 shows another step of an exemplary method for producing a vacuum cleaner filter bag;

[0062] FIG. 3 shows another step of an exemplary method for producing a vacuum cleaner filter bag;

[0063] FIG. 4 shows another step of an exemplary method for producing a vacuum cleaner filter bag;

[0064] FIG. 5 shows another aspect of an exemplary method for producing a vacuum cleaner filter bag;

[0065] FIG. 6 shows an exemplary vacuum cleaner filter bag;

[0066] FIG. 7 shows an alternative embodiment of the nonwoven fabric element;

[0067] FIG. 8 shows another alternative embodiment of the nonwoven fabric element; and

[0068] FIG. 9 shows another alternative embodiment of the nonwoven fabric element.

[0069] FIG. 1 shows a first step of an exemplary method for producing a vacuum cleaner filter bag according to the invention. In this step, by way of example, two through-openings 1, 2 are punched into a sheet of nonwoven fabric that is moved stepwise in the machine direction (indicated by an arrow in FIG. 1) during the method. As can be seen in FIG. 1, a nonwoven fabric element 3 that extends in the machine direction is left between the two through-openings 1, 2. Here, the two through-openings 1, 2 form a region free of nonwoven fabric that comprises the two through-openings 1, 2 as non-contiguous sub-regions. The edge of the region free of nonwoven fabric is formed by the two edges of the through-openings 1, 2. The nonwoven fabric element 3 is arranged between two opposing edge portions A, B of the edge of the region free of nonwoven fabric. The nonwoven fabric element 3 is spaced apart from the edge portions A, B in each case by means of a sub-region of the region free of nonwoven fabric, namely by means of the through-opening 1 and 2, respectively.

[0070] When the sheet of nonwoven fabric is moved along further after the through-openings 1, 2 have been punched, it is drawn in the machine direction. In the prior art, in which the nonwoven fabric element 3 was not provided, this being drawn in the machine direction resulted in a deformation of the single through-opening provided, which led to disadvantages during further processing. Therefore, in the prior art, the sheet of nonwoven fabric had to be moved slowly and carefully. However, by virtue of the nonwoven fabric element 3, the region of the through-openings 1, 2 is stabilized during a tug in the machine direction, such that higher processing speeds are possible.

[0071] As can also be seen in FIG. 1, the two through-openings 1, 2 are symmetrical with respect to an axis of symmetry 4 that extends in the machine direction. The region comprising the nonwoven fabric element 3 and the through-openings 1, 2 has a rectangular, in particular square, boundary in plan view.

[0072] In this case, the nonwoven fabric element 3 comprises a central region in the shape of a disc and two connection pieces that oppose one another in the machine direction and that connect the region in the shape of a disc to parts of the above-mentioned boundary.

[0073] The sheet of nonwoven fabric is merely shown schematically in the present case, in particular the borders 5, 6 thereof extending transversely to the machine direction.

[0074] In another method step illustrated in FIG. 2, a plastic film is connected to the sheet of nonwoven fabric from underneath the sheet of nonwoven fabric, such that, when the sheet of nonwoven fabric is viewed in plan view, the plastic film (as shown in FIG. 2) completely overlaps with the region free of nonwoven fabric and the nonwoven fabric element 3. The points at which the plastic film is welded to the sheet of nonwoven fabric are indicated in FIG. 2 by means of dashed lines. In particular, the plastic film can be welded to a part of the sheet of nonwoven fabric which completely surrounds the region free of nonwoven fabric, i.e. to the above-described boundary of the region comprising the through-openings 1, 2 and the nonwoven fabric element 3. As a result, the circumferential weld seam 7 shown in FIG. 2 is produced. Optionally, the plastic film may also be connected to the nonwoven fabric element 3, for example by means of a weld seam 8 that extends in the machine direction.

[0075] In the finished form of the vacuum cleaner filter bag, the regions of the plastic film that are not overlapped by the nonwoven fabric element 3 form a first sub-region of a film region that, in the case of a transparent film, serves as a sort of viewing window such that it is possible to visually determine how full the vacuum cleaner filter bag is and, in the case of a non-transparent film, contributes to easier insertion of the vacuum cleaner filter bag into a corresponding receptacle in the vacuum cleaner.

[0076] FIG. 3 shows another method step of the exemplary method for producing a vacuum cleaner filter bag, in which the future fill hole, in particular, is formed in the bag wall. To do this, the nonwoven fabric element 3 and the plastic film are punched at the same time, such that a through-hole 9 is formed. The simultaneous punching of the nonwoven fabric element 3 and the plastic film is procedurally advantageous. However, the method according to the invention is not limited to simultaneous punching.

[0077] By punching the through-hole 9, the previously disc-shaped central part of the nonwoven fabric element 3 is formed into an annular region 10 that is connected via two connection pieces 11, 12 to the rest of the sheet of nonwoven fabric, in particular to the weld seam 7.

[0078] The shape and radial extent of the annular region 10 is adapted to the region of the retaining plate which is provided for connection to the bag wall. This region of the retaining plate typically comprises guides in order to improve welding of the retaining plate to the bag wall.

[0079] Finally, FIG. 4 illustrates the step of connecting the retaining plate 13 to the annular region 10 and to the plastic film (weld region indicated by a dashed line). Because the retaining plate is connected not only to the plastic film but also to the nonwoven fabric element 3, a secure connection between the retaining plate 13 and plastic film is possible.

[0080] As known per se, the retaining plate 13 comprises a sealing lip 14 and a closure cap (closure cap not shown in FIG. 4). By virtue of the closure cap, vacuumed material can be prevented from escaping when the full bag is removed from the vacuum cleaner housing.

[0081] As can be seen in FIG. 4, the retaining plate 13 overlaps with the nonwoven fabric element 3 almost completely, but only partially overlaps with the first sub-region of the film region. As a result, the first sub-region of the film region can be used as a viewing window in order to check how full the vacuum cleaner bag is if a transparent plastic film is used. Only small amounts of the connection pieces 11, 12 are visible, but these do not interfere with the function of the viewing window. Ultimately, a result that is comparable to the prior art (comparable, for example, to EP 3 066 968) but having a more secure connection between the retaining plate 13 and the bag wall is achieved.

[0082] FIG. 5 shows other possible weld regions in which the plastic film can be connected to the nonwoven fabric element 3. In this case, for example, welding takes place also along the annular element 10 as well as along the connection pieces 11, 12. The circumferential weld seam 7 is also shown. Depending on the specific embodiment, the retaining plate 13 may also be connected to connection pieces 11, 12 if required (in addition to the connection in the region of the annular element 10).

[0083] Finally, a vacuum cleaner filter bag can be assembled by cutting the sheet of nonwoven fabric to the appropriate size and for example interconnecting two nonwoven fabric layers by means of a circumferential weld seam. One of the two nonwoven fabric layers comprises the film region and the retaining plate. FIG. 6 is a plan view of a simple vacuum cleaner filter bag of this kind. As is known per se, however, the vacuum cleaner filter bag may have other geometries. For example, side folds may be provided on the both longitudinal sides and/or transverse sides in order to achieve a smaller packing size with the same filter surface area.

[0084] Instead of connecting the plastic film from underneath the sheet of nonwoven fabric, as shown in FIG. 2, the plastic film could be connected to the sheet of nonwoven fabric from above, when viewing the sheet of nonwoven fabric in plan view. This ultimately results in that the plastic film is arranged between the nonwoven fabric element and the retaining plate in the produced vacuum cleaner filter bag. The inventors of the present application have found that this configuration also allows for a more secure connection between the retaining plate and bag wall, since the nonwoven fabric element in this case forms a softer, more flexible substrate for the welding than the conveyor on which the sheet of nonwoven fabric otherwise lies.

[0085] Furthermore, it is possible to partially or fully thermally compact, for example by means of ultrasound or pre-embossing, the regions of the sheet of nonwoven fabric in which the through-openings 1, 2 are to be punched (cf. FIG. 1) before the punching. As a result, the punched holes are formed with more defined borders.

[0086] The geometry of the nonwoven fabric element 3 is shown merely by way of example in FIG. 1. Other examples can be found in FIGS. 7 to 9.

[0087] In FIG. 7, the disc-shaped region of the nonwoven fabric element 3 is connected to the rest of the sheet of nonwoven fabric via four connection pieces, which are arranged in pairs on opposing sides of the disc-shaped region. This geometry is achieved by punching four through-openings 14, 15, 16, 17, which form the region free of nonwoven fabric. The nonwoven fabric element 3 is arranged between the edge portions A-B, C-D, E-F and G-H.

[0088] In FIG. 8, the disc-shaped region of the nonwoven fabric element 3 is connected to the rest of the sheet of nonwoven fabric via three connection pieces. Two of the connection pieces form an angle of 45 with the machine direction. This geometry is achieved by punching three through-openings 18, 19, 20, which form the region free of nonwoven fabric. The nonwoven fabric element 3 is arranged between the edge portions A-B, C-D and C-E.

[0089] However, it is also possible to connect the disc-shaped region to the rest of the sheet of nonwoven fabric via only one connection piece, as shown in FIG. 9. In this case, too, only one through-opening 21 is provided, which forms the region free of nonwoven fabric. The nonwoven fabric element 3 is arranged between the edge portions A and B and is spaced apart from each of these edge portions A, B in each case by means of a different sub-region of the region free of nonwoven fabric. Again, only one connection piece is used to simplify the positioning of the nonwoven fabric element 3. This improves assembly of the retaining plate.

[0090] It should be understood that features mentioned in relation to the above-described exemplary embodiments are not limited to specific combinations and, as such, any other desired combinations are also possible. In particular, it should be understood that geometries shown in the figures, for example those of the retaining plate, are merely exemplary and, as such, any other desired configurations are also possible.