Vacuum Cleaner Filter Bag Having a High-Strength Weld Seam, Method for Producing Said Vacuum Cleaner Filter Bag, and Ultrasonic Welding System for Producing an Ultra-Strong Weld Seam

Abstract

The present invention relates to a vacuum cleaner filter bag made of a thermally weldable filter material which forms the sealed internal space of the vacuum cleaner filter bag. The internal space is thereby closed at least on one side by means of a weld seam configured according to the invention, in the case of which at least two layers of the filter material are welded together. The weld seam configured according to the present invention is distinguished by a far higher tearing strength, compared with weld seams as are known from the state of the art. The invention relates in addition to a method for the production of the vacuum cleaner filter bag, to a tool for the production of the high-strength weld seam and also to an ultrasonic welding unit in which this tool is integrated.

Claims

1. A vacuum cleaner filter bag made of a thermally weldable filter material, a sealed internal space of the vacuum cleaner filter bag being defined by the filter material, the internal space being closed at least on one side of the vacuum cleaner filter bag by a linearly extending weld seam, in which at least two layers of filter material are welded together, the weld seam has, in a direction of a linear course, alternately welded and non-welded regions of the at least two layers, the welded regions having a dimensioning, measured in the direction of the linear course, of 1.0 mm to 10.0 mm a dimensioning, measured perpendicular to the linear course of 1.3 mm to 10.0 mm and the non-welded regions having a dimensioning, measured in the direction of the linear course, of >1.0 mm to 5.0 mm.

2. The vacuum cleaner filter bag according to claim 1, wherein the non-welded regions have the dimensioning, measured in the direction of the linear course, of 1.2 mm to 5.0 mm.

3. The vacuum cleaner filter bag according to claim 1, wherein the welded regions have the dimensioning, measured in the direction of the linear course, of 1.5 mm to 7.5 mm.

4. The vacuum cleaner filter bag according to claim 1, wherein, in the direction of the linear course of the weld seam, the dimensioning of the welded regions is greater than the dimensioning of the non-welded regions.

5. The vacuum cleaner filter bag according to claim 1, wherein the alternating arrangement of the welded and non-welded regions is equidistant.

6. The vacuum cleaner filter bag according to claim 1, wherein the weld seam has a dimensioning, measured perpendicular to the linear course of 1.3 mm to 5.0 mm.

7. The vacuum cleaner filter bag according to claim 1, wherein the welded regions have a substantially rectangular or rectangular configuration.

8. The vacuum cleaner filter bag according to claim 1, wherein each layer of the filter material is a single or multilayer nonwoven material, preferably with a total basis weight of at least 400 g/m2.

9. The vacuum cleaner filter bag according to claim 8, wherein the nonwoven material has at least 3 layers.

10. The vacuum cleaner filter bag according to claim 1, wherein the weld seam has a tensile strength, measured according to DIN EN 29073-3, of at least 30 N.

11. The vacuum cleaner filter bag according to claim 1, wherein a) in the form of a flat bag in which at least two layers of the filter material are welded together circumferentially at the edge, the welding being configured at least in regions, as weld seam, as defined in claim 1, or b) in the form of a side-gusseted bag in which the vacuum cleaner filter bag has two longitudinal- and two transverse sides, at least two layers of the filter material being welded together on the longitudinal side and being folded into the vacuum cleaner filter bag and being welded together on the transverse side, at least the transverse-side weld seams being configured as defined in claim 1, or c) in the form of a 3D bag or block- or block-bottom bag in which at least two layers of the filter material are welded with a weld seam as defined in claim 1.

12. A method for the production of a vacuum cleaner filter bag according to claim 1, in which at least one linearly extending weld seam is produced by thermal welding, the weld seam having, in the direction of the linear course, alternately welded and non-welded regions of the at least two layers, the welded regions having a dimensioning, measured in the direction of the linear course, of 1.0 mm to 10.0 mm and the non-welded regions having a dimensioning, measured in the direction of the linear course, of >1.0 mm to 10.0 mm.

13. The method according to claim 12, wherein the linear weld seam is produced by ultrasonic welding, a tool being used, comprising a basic body and also at least one bar which extends longitudinally in an x-direction, has a width (B) in a y-direction and is projected in a z-direction, with a planar working surface which terminates in the z-direction and has a plurality of notches which extend parallel in the y-direction and are recessed starting from the working surface in the z-direction, defining a plurality of weld faces, a longitudinal dimensioning of the notches in the x-direction being of >1.0 mm to 10.0 mm and a longitudinal dimensioning of the weld faces in the x-direction being 1.0 mm to 10.0 mm, and also a counterpart to the tool which is disposed above the bar during the welding process, the at least two layers of filter material for producing the weld seam being disposed between the tool and counterpart, tool and counterpart being moved towards each other so the at least two layers of filter material are adapted and, for the welding, ultrasound is coupled into the counterpart or into the tool.

14. A tool for an ultrasonic welding unit, comprising a basic body and also at least one first bar which extends longitudinally in an x-direction, has a width (B) in a y-direction and is projected in a z-direction, with a planar working surface which terminates in the z-direction and has a plurality of notches which extend parallel in the y-direction and are recessed starting from the working surface in the z-direction, defining a plurality of weld faces, a longitudinal dimensioning of the notches in the x-direction being of >1.0 mm to 10.0 mm and a longitudinal dimensioning of the weld faces in the x-direction being 1.0 mm to 10.0 mm and a dimensioning, measured perpendicular to the linear course of 1.3 mm to 10.0 mm.

15. The tool according to claim 14, wherein the longitudinal dimensioning of the notches in the x-direction is of 1.2 mm to 8.0 mm.

16. The tool according to claim 14, wherein the longitudinal dimensioning of the weld faces in the x-direction is of 1.5 mm to 7.5 mm.

17. The tool according to claim 14, wherein the longitudinal dimensioning of the weld faces in the x-direction is greater than the longitudinal dimensioning of the notches.

18. The tool according to claim 14, wherein the notches are disposed equidistantly in the x-direction.

19. The tool according to claim 14, wherein the width (B) of the weld faces in the y-direction is, of 1.3 mm to 5.0 mm.

20. The tool according to claim 14, wherein the weld faces have a substantially rectangular or rectangular outline.

21. The tool according to claim 14, wherein the notches, in projection on an xz-plane, have a triangular or trapezoidal profile, sides of the notches forming the triangular profile or the trapezoidal profile preferably having an angle (a) of 30° to 120°, relative to each other.

22. The tool according to claim 14, wherein the basic body has at least one second bar which extends longitudinally in an x-direction, has a width (B′) in a y-direction and is projected in a z-direction, with a planar working surface which terminates in the z-direction and has a plurality of notches which extend parallel in the y-direction and are recessed starting from the working surface in the z-direction, defining a plurality of weld faces, a longitudinal dimensioning of the notches in the x-direction being of >1.0 mm to 10.0 mm and a longitudinal dimensioning of the weld faces in the x-direction being 1.0 mm to 10.0 mm, the at least one second bar being disposed parallel in the x-direction and at a spacing (d) relative to the at least one first bar, and the working surface of the at least one second bar having a same dimensioning in the z-direction as that of the at least one first bar.

23. The tool according to claim 22, wherein between the first bar and the second bar, at least one third bar which is projected in a z-direction being disposed, with a planar working surface which terminates in the z-direction with recesses extending in the z-direction, defining a plurality of weld faces, the working surface of the at least one third bar having a same dimensioning in the z-direction as that of the at least one first bar.

24. An ultrasonic welding unit comprising: a tool according to claim 14 and also at least one sonotrode with a continuously configured working surface, the at least one sonotrode and the tool being disposed moveably relative to each other such that, during the welding process, the at least one sonotrode and the at least one first bar are disposed one above the other, or an anvil with a continuously configured working surface and a tool according to claim 14 which is operated as a sonotrode, the anvil and the tool being disposed moveably relative to each other such that, during the welding process, the anvil and the at least one first bar are disposed one above the other.

Description

[0047] The present invention is described in more detail with reference to the subsequently appended Figures without restricting the invention to the specially produced embodiments.

[0048] FIG. 1 shows the plan view on the working surface of a tool according to the invention in z-direction.

[0049] FIG. 2 shows the side view of a tool according to the invention in y-direction.

[0050] FIG. 3 shows the plan view on a tool according to the invention in x-direction.

[0051] FIG. 4 shows the complete view of a tool according to the invention in y-direction.

[0052] FIG. 5 shows a vacuum cleaner filter bag according to the invention which is configured as a flat bag.

[0053] FIG. 6 shows a vacuum cleaner filter bag according to the invention which is configured as a side-bag.

[0054] FIG. 1 shows a section of a plan view onto a section of the working surface of a tool 1 according to the invention. The tool 1 thereby has a basic body G and also two bars 2 and 2′ which protrude from the basic body G in z-direction. The bars 2 and 2′ thereby extend in x-direction. The bars 2 or 2′ thereby have notches 3 or 3′, the surface of the bars 2 or 2′ is hereby notched and recessed at the bottom in z-direction. By means of the notches 3 and 3′, the projecting weld faces 4 or 4′ which protrude from the working surface of the tool 1 in z-direction are thereby produced.

[0055] The notches 3 and 3′ are thereby disposed equidistantly in x-direction such that the thereby resulting weld faces 4 or 4′ are configured to be of equal length (and likewise equally wide). The two bars 2 and 2′ of the tool 1 are thereby configured to be mirror-symmetrical with respect to an x-axis. The minimum spacing of these two bars d is configured the same over the entire x-dimensioning of the tool 1 so that the bars 2 and 2′ extend parallel to each other.

[0056] In x-direction, the length of the weld faces 4 and 4′ is thereby between 1.0 and 10 mm, whilst the length of the notches in x-direction 3 or 3′ is between >10 mm to 10 mm.

[0057] The weld faces 4 or 4′ of the respective bars 2 or 2′ thereby have a width B or B′, i.e. a dimensioning in y-direction.

[0058] Between the bars 2 and 2′, a further bar 2″ is thereby disposed, which likewise has projected weld faces 4″ in z-direction. The respective weld faces 4″ are thereby separated from each other by notches 3″. The bar 2′ has, compared with bars 2 or 2′, merely half as many notches so that the weld faces 4″ appear only half as often in x-direction as in bars 2 or 2′.

[0059] At the places at which a weld face 4″ coincides, in x-direction, with a weld face 4 or 4′, these are separated from each other by notches 5 or 5′.

[0060] Whilst the notches 3 or 3′ of the bar 2 or 2′ can have for example a triangular configuration (see also FIG. 2 in this respect) so that the notches have corresponding sides F, the notches 3″ or the notches 5 or 5′ present between the bars can also be configured differently and for example have no edges, for example have a round profile (see also FIG. 3 in this respect).

[0061] FIG. 2 shows a plan view on the xz-plane of the tool 1. The regularly disposed notches 3 which have a triangular configuration and have respectively sides F are hereby detectable. The sides are thereby disposed at an angle α relative to each other. In FIG. 2, the interaction of the weld faces 4 and the weld faces 4″ is likewise detectable, the repetition rate of the weld faces 4″ in x-direction is thereby merely half as high as the repetition rate of the weld faces 4 for example of the first bar 2 so that weld faces 4″ of the bar 2″ are present merely at the rate of each second weld face 4 of the bar 2.

[0062] FIG. 3 shows a plan view on the tool according to the invention in x-direction, i.e. on the yz-plane. FIG. 3 corresponds to a section in the yz-plane through FIG. 1 at a place at which both weld faces 4, 4′ and 4″ are configured. In FIG. 3, the respective weld faces 4, 4′ and 4″ are illustrated detectably as projected in z-direction, these weld faces are thereby separated from each other by notches 5 or 5′ which, in the case of the embodiment of FIG. 3, present semi-circular notches.

[0063] FIG. 4 finally illustrates the total perspective view of a welding tool 1 according to the invention, in particular the enlarged dimensioning of the basic body G is hereby illustrated. The welding tool according to the invention has notches 3 or a corresponding number of weld faces 4 for the case of the embodiment 80 illustrated in FIG. 4, by way of example.

[0064] FIGS. 5a to 5c show a vacuum cleaner filter bag 10 according to the invention which is configured as a flat bag. FIG. 5a thereby shows a perspective plan view on the front-side V of the vacuum cleaner filter bag 10 according to the invention in the form of a flat bag, whilst FIG. 5b shows the section through the vacuum cleaner filter bag at the section line A-B illustrated in FIG. 5a. FIG. 5c shows a section through the line A′-B′ illustrated in FIG. 5a, i.e. through the circumferential weld seam S.

[0065] The vacuum cleaner filter bag 10 in the form of a flat bag according to FIG. 5a thereby has a front-side V and also a rear-side R. Front- and rear-side V or R are thereby formed respectively from a thermally weldable filter material, for example a single or multilayer nonwoven material. The front-side V thereby has an inflow opening E, by means of which the discharge connection piece of a vacuum cleaner, not illustrated, can be connected to the vacuum cleaner filter bag 10. The front-side V and the rear-side R are joined together other circumferentially by a weld seam S.

[0066] The section through the vacuum cleaner filter bag, as illustrated in FIG. 5b, shows the join of the front-side V and of the rear-side R of the vacuum cleaner filter bag via the weld seam S. Front- and rear-side are held together by welded regions 40 of the weld seam S.

[0067] In FIG. 5c, the configuration according to the invention of the weld seam is illustrated at the position of the section A′-B′, as shown in FIG. 5a. The weld seam S thereby has non-welded regions 30 and also welded regions 40 which are alternating and equidistant. In the region of the welded regions 40, the filter material of the front-side V and of the rear-side R is joined together. During the welding process, the result hereby is melting and adhesion of the thermally weldable filter material both of the front-side V and of the rear-side R. In the region of the non-welded regions 30, no melting of the layers of the filter material hereby takes place. The filter material both of the front-side V and of the rear-side R is preserved here. The layers of filter material V and R are hereby situated however one above the other in a form-fit and are shaped to form beads. The configuration according to the invention of the weld seam thereby provides that the non-welded regions 30 have, along the weld seam, i.e. in the case of the illustration in FIG. 5c given by way of example, along the section line A′-B′, a dimensioning of >1.0 mm to 5.0 mm. The welded regions 40 thereby have a longitudinal dimensioning along the section line A′-B′ of 1.0 mm to 10.0 mm. Preferably, the non-welded regions 30 and the welded regions 40 are disposed alternating and equidistantly, i.e. non-welded regions 40 and welded regions 30 alternate at the same repetition rate.

[0068] FIG. 6a illustrates a vacuum cleaner filter bag 10 according to the invention in the form of a side-gusseted bag. This vacuum cleaner filter bag 10 has two longitudinal sides L and also two transverse sides Q and also likewise a front-side V and a rear-side R. Front-side V and rear-side R are likewise formed from a thermally welded filter material, for example a single or multilayer nonwoven material. On the front-side V, an inflow opening E is present. In the region of the longitudinal sides L, the filter material is folded in both on the front-side V and on the rear-side R so that, on the longitudinal side, two side edges K1 and K2 are present. The side edge K1 is thereby present in the filter material of the front-side V, whilst the side edge K2 is assigned to the filter material web of the rear-side R. The front-side V and rear-side R are thereby joined, on the end-side, i.e. in the region of the transverse side Q, by means of a weld seam S1, in the region of the fold, front-side V and rear-side R are joined by means of a weld seam S2.

[0069] FIG. 6b illustrates a section through the vacuum cleaner filter bag 10 according to the invention in the form of a flat bag along the section line A-B, as illustrated in FIG. 6a. It is detectable how the filter material of the front-side V and also of the rear-side R is present folded in and is joined there by means of a weld seam S2. As a result of the folding-in, the side-edges K1 are thereby produced in the front-side V or K2 in the rear-side R. By means of folding in the front-side V and the rear-side R, there are thereby produced, in the vacuum cleaner filter bag 10 as a flat bag, two regions I and II, of which—in the projection direction of front-side V on the rear-side R—for example four layers of filter material being disposed one above the other (region I) or two layers of filter material being disposed one above the other (region II).

[0070] FIG. 6c shows a section along the section line A′-B′ according to FIG. 6a, i.e. through a weld seam S1, disposed on the end-side, of the vacuum cleaner filter bag 10 according to the invention in the form of a side-gusseted bag. This weld seam S1 thereby has non-welded regions 30 or welded regions 40, at which the layers of filter material of the front-side V and of the rear-side R, which are situated respectively one above the other, are joined together. All the layers of filter material are melted together inside the weldable regions 40. In region I in which, as illustrated in FIG. 6b, four layers of filter material are situated one above the other, all of the four layers are joined together in the region of the welded regions 40. In region II, merely two layers of filter material are welded together inside the welded regions 40, i.e. are present melted together. The non-welded regions 30 are thereby disconnected inside regions I such that the four layers of filter material, present there, are present not joined together, but are present pressed together in a form-fit. The beads illustrated in FIG. 6c are hereby produced. Inside region II, merely two layers of filter material are present so that here an identical configuration of the weld seam, as in FIG. 5c, is illustrated. The weld seam S2, i.e. the weld seam situated inside the vacuum cleaner filter bag at the join of the front-side V and of the rear-side R can thereby be configured identically as in FIG. 5c.

[0071] Table 1 shows test results which can be achieved in the case of vacuum cleaner filter bags with weld seams configured according to the invention.

TABLE-US-00001 TABLE 1 Spacing Number Width Length between Basis of Total of the of the the Tensile weight of welded basis weld weld weld strength nonwoven layers weight face face faces Angle at break Examples (g/m.sup.2) (n) (g/m.sup.2) (mm) (mm) (mm) (°) (N)  1* 175 4 700 1.0 2.0 0.8 45 29 2 175 4 700 1.5 2.5 1.5 45 102 3 175 4 700 1.5 3.0 2.0 60 103 4 175 4 700 1.5 2.5 2.5 90 95

[0072] Table 1 shows the results of the tearing strength (tensile strength at break) measurements with reference to welded filter materials according to DIN EN 29073-3. The welded filter materials to be examined are thereby clamped between the jaws of the tensile testing machine such that the weld seam to be tested is disposed centrally between the jaws. The test pieces thereby have 4 welded material layers, respectively two layers of material are hereby clamped into respectively one jaw of the tensile testing machine. The weld seams of the examined test pieces thereby have alternately disposed welded and non-welded regions. In the case of comparative example 1*, the spacing between the weld faces is respectively merely 0.8 mm, whilst, in the examples 2-4 according to the invention, the spacing between the weld faces is chosen to be greater.

[0073] Comparative example 1* shows clearly that a small spacing between the weld faces delivers poor results in particular with a high total basis weight of the welded material layers. The examples 2, 3 and 4 according to the invention, which are comparable hereto, display surprisingly significantly higher tensile strengths at break in total of the resulting weld seam although the density of the weld points turns out to be smaller because of the greater spacing of the welded regions relative to each other than in the case of comparative example 1*.

[0074] Example 2 shows that increasing the spacing between the weld faces to for example 1.5 mm has excellent effects on the maximum tensile strength of the sample. In particular in the case of four welded material layers, an increase of tensile strength at break by approx. 300% can be detected. Increasing the spacing between the weld faces influences the result hence in a surprisingly positive manner. Also further increasing the spacing between the weld faces (see for example examples 3 and 4) shows clearly that surprisingly, in particular with high total area weights, i.e. for example four welded layers, a significant increase in tensile strength at break can be observed.