RETAINING PLATE WITH CENTERING DEVICE

The invention concerns a retaining plate for a vacuum cleaner bag.

Such retaining plates are known in many different forms, and have a passage or filling opening through which the connection nozzle of a vacuum cleaner can be inserted into the vacuum cleaner bag. Such vacuum cleaner nozzles can have very different diameters. In order to be able to use one retaining plate for different nozzle diameters, an elastic seal or sealing ring is often used. Such seals are usually made of rubber or a thermoplastic elastomer (TPE). They can be formed integrally with the retaining plate, or as a separate component on or under the retaining plate, or in the filter bag. Retaining plates made of cardboard, where pre-cut parts can be cut out to adapt the diameter of the opening to the vacuum cleaner nozzle, are also known.

In particular, a vacuum cleaner bag is known from DE 20 2008 004 025, in which an elastic rubber layer is arranged between a retaining plate and the vacuum cleaner bag, which is reinforced by a further stiff material layer. In DE 20 2008 002 010 U1, a dust collection bag is directly glued to a seal made of a polymeric material. DE 10 2010 060 353 A1 describes a vacuum cleaner bag comprising a plane, elastic sealing element which is arranged inside and/or outside the bag wall. A vacuum cleaner bag is known from DE 20 2004 008971 U1, in which a flexible sealing ring is welded to the bag, and the retaining plate is welded to the sealing ring. DE 10 2007 062 028 B4 describes a dust filter bag in which a layer of rubber-elastic material forms a protruding sealing ring on the inside of the filter bag.

In the following, the term “reference position” refers to the relative position of a retaining plate to a vacuum cleaner nozzle that is inserted into the plate, in the case when an unfilled vacuum cleaner bag is fixed in the housing of a vacuum cleaner. In the reference position, the vacuum cleaner nozzle is usually centered in the passage opening, i.e., in the plane in which the passage opening extends, the distance between the vacuum cleaner nozzle and the edge of the passage opening is essentially constant along the entire circumference of the vacuum cleaner nozzle. In the reference position, the seal seals the vacuum cleaner nozzle evenly around its circumference. This means that the sealing properties of the retaining plate are optimal in the reference position.

Depending on the arrangement of the retaining plate in the installation space of a vacuum cleaner, it may occur that the retaining plate is displaced in a radial direction relative to the reference position when the vacuum cleaner bag is filled with dust due to the weight of the suction material. Here, “radial” refers to directions that lie in the plane in which the passage opening extends. On the other hand, the vacuum cleaner nozzle itself is usually not displaced by the weight of the suction material, as, in operation, it is additionally fixed by the vacuum cleaner housing, which has a much higher rigidity than the retaining plate.

Such a radial displacement of the retaining plate leads, in particular, to the passage opening being displaced from the reference position relative to the vacuum cleaner nozzle which is inserted into the retaining plate. This often leads to a deformation of the seal and thus to a deterioration of the sealing properties.

Further, the retaining plate can shift in its holder when the vacuum cleaner is opened to check the level of the dust bag, which often involves removing the vacuum cleaner nozzle from the bag. This, in turn, leads to a radial displacement of the vacuum cleaner nozzle and the passage opening relative to each other when the vacuum cleaner is closed, and, as a consequence, to the negative effects on the sealing properties described above.

The object of the invention is therefore to provide a retaining plate which enables reliable sealing.

This object is achieved by a retaining plate according to claim 1. Particularly advantageous further embodiments are listed in the dependent claims.

The retaining plate comprises a sealing element and a base plate in which a passage opening is formed. In particular, the passage opening can be circular. However, other shapes of the passage opening are also possible, for example it can be oval, in particular ellipsoidal, or rectangular.

The retaining plate may be configured to be attached to a retaining device in a vacuum cleaner housing. Alternatively, the vacuum cleaner filter bag may be configured to be slid over a connection nozzle on the side of the vacuum cleaner with the help of the retaining plate.

The sealing element is intended to prevent or limit the escape of dust from the vacuum cleaner filter bag by sealing the area between the inner edge of the passage opening and the outside of a connection nozzle of the vacuum cleaner. The sealing element can be made of rubber and/or TPE and/or the material of the vacuum cleaner filter bag. However, it can also be made of any other material that has sufficient elasticity to provide the necessary sealing effect. The sealing element can be moulded onto the retaining plate.

The inventors of the present application have recognized that a problem with conventional retaining plates is that the gaskets used therein do not have sufficient resilience to compensate for the displacements described above. For this reason, the retaining plate comprises a centering device which extends at least partially along the edge of the passage opening, and comprises at least one first spring element. According to the invention, the spring element, when deformed in a radial direction, exerts a restoring force opposing the deformation.

If a deformation of the spring element results from a radial displacement of the passage opening relative to a vacuum cleaner nozzle received in the retaining plate, the centering device ensures, by means of the restoring force, that the retaining plate is held in the reference position relative to the vacuum cleaner nozzle and/or is returned to the reference position. In other words, the deformation of the spring element creates a spring force which is transferred to the vacuum cleaner nozzle. Since the nozzle is fixed by the vacuum cleaner housing, as explained above, the resulting counterforce acting from the vacuum cleaner nozzle on the retaining plate results in a displacement of the retaining plate which is opposite to the original radial displacement.

The spring element may be formed from a deformed region of the retaining plate, in particular the base plate.

The deformed area may preferably be deformed in a wave-like manner, and such deformation may include one or more waves. A wave is defined as an elevation and/or depression perpendicular to the main plane of extension of the retaining plate. In addition, a plane area adjoining an elevation and/or depression can also be part of the wave. The profile of such an elevation can be V- or U-shaped, for example. If the deformed area contains several waves, the individual waves may have the same profile or different profiles. In the case of several waves, all waves may consist of elevations or depressions, or elevations and depressions may alternate. The individual waves may be directly adjacent to each other or they can be separated from each other by undeformed regions of the retaining plate.

The waves may be arranged concentrically in relation to the passage opening. Here, concentric means that the waves run essentially parallel to the edge of the opening.

On the one hand, such a deformation directly causes the deformed region to assume spring-like properties. Further, the deformed region can be compressed, thus allowing for the insertion of vacuum cleaner nozzles with different diameters. Instead of waves, the deformed region may also include other structures that give the region spring-like properties.

The dimensions of the deformed region in the circumferential direction of the opening may increase in a radially outward direction. For example, in the case of a circular passage opening, the spring element may be formed by the wave-like deformation of a circular ring sector of the retaining plate, i.e. by a segment of the retaining plate which, starting from the center of the passage opening, is formed by two different radii and an intermediate circular ring. Such a design makes it easy to ensure that the restoring force acts perpendicular to the edge of the passage opening.

The retaining plate may be manufactured in several pieces. The centering element may be glued or welded to the base plate.

Alternatively, the retaining plate may be formed integrally, in particular the centering device may be formed integrally with the base plate. In this embodiment, the centering device may form at least part of the edge of the passage opening.

The retaining plate may also include at least a second spring element. In this case, the arrangement of the spring elements may in particular be such that it has no rotational symmetry with respect to the passage opening. In this case, n-fold rotational symmetry of the arrangement of the spring elements with respect to the passage opening is to be understood as meaning that the arrangement of the spring elements can be transformed into itself by a rotation of 360°/n about an axis corresponding to the central axis of the vacuum cleaner nozzle in the reference position. It should be noted that a “one-fold” rotational symmetry is equivalent to no rotational symmetry. By arranging the spring elements in this way, it is possible to achieve a stronger spring effect against a main load direction. For example, the main load direction can be the direction of gravity when the vacuum cleaner is in operation.

The spring elements may be of the same size or of different sizes. In particular, they may have different dimensions in the circumferential direction of the passage opening. Furthermore, the spring elements can be spaced apart from each other in the circumferential direction, or they may only be separated by cut-outs. In other words, between every two spring elements there can be an undeformed region of the retaining plate, or a free space.

The centering device of the retaining plate may also be formed as a diaphragm spring. Here, a diaphragm spring describes a spring which extends essentially in a main expansion plane, wherein the dimensions in this plane (length, width) are many times greater than in a direction perpendicular to this plane (thickness). The diaphragm spring has a restoring force perpendicular to its main expansion plane. In this way, it is possible to achieve stabilization of the inserted vacuum cleaner nozzle not only in the radial but also in the axial direction, i.e. against displacement along its central axis. For example, the deformation of the retaining plate due to the weight of the vacuumed material can be prevented or compensated for even if the central axis of the vacuum cleaner nozzle is parallel to the direction of gravity during operation.

The retaining plate may include a thermoplastic. In particular, the centering device may be made wholly or partly of a thermoplastic material. In particular, the spring elements can be made of a thermoplastic. In this context, a thermoplastic is understood to be a thermoplastic material that is not a thermoplastic elastomer. The thermoplastic can be, for example, polyethylene terephthalate (PET), polycarbonate (PC), rigid polyvinyl chloride (rigid PVC), polypropylene (PP), polyethylene (PE) or polyactate (PLA). In one embodiment the thermoplastic can be a recycled plastic, for example recycled PET (rPET) or recycled PP (rPP). This can improve the environmental compatibility of the retaining plate.

The retaining plate may be manufactured by thermoforming or deep drawing. Production by injection moulding is also possible.

The invention further provides a vacuum cleaner filter bag according to claim 11, comprising a bag wall and one of the retaining plates described above.

The retaining plate may therefore have one or more of the features described above.

The bag wall of the vacuum cleaner filter bag may comprise one or more layers of filter material, in particular one or more layers of nonwoven fabric. Vacuum cleaner filter bags with such a bag wall consisting of several layers of filter material are known from EP 2 011 556 or EP 0 960 645, for example. As material for the nonwoven layers, a wide variety of plastics can be used, for example polypropylene and/or polyester. In particular, the layer of the bag wall to be connected to the retaining plate can be a nonwoven layer. The bag wall of the vacuum cleaner filter bag may also contain or consist of recycled plastic. For example, the bag wall can be designed as described in EP 3 219 376 A1.

The term nonwoven (German “Vliesstoff”) is used according to the definition in ISO Standard IS09092:1988 or CEM Standard EN29092. In particular, the terms fibrous web or web and nonwoven fabric are defined in the field of the manufacture of nonwoven fabrics and also to be understood in the sense of the present invention as follows. For the manufacture of a nonwoven, fibers and/or filaments are used. The loose or loose and still unbound fibers and/or filaments are referred to as web or fibrous web. Via a so-called web bonding step, a nonwoven fabric is finally formed from such a fibrous web, which has sufficient strength to be, e.g., wound up into rolls. In other words, a nonwoven fabric is made self-supporting by bonding. (Details of the use of the definitions and/or processes described herein can also be found in the standard work “Nonwovens”, W. Albrecht, H. Fuchs, W. Kittelmann, Wiley-VCH, 2000).

The bag wall may have a passage opening, in particular such that the passage opening of the bag wall is aligned with the passage opening of the base plate. Through the passage opening in the base plate and the passage opening in the bag wall, an inlet opening can be formed through which the air to be cleaned can flow into the interior of the vacuum cleaner filter bag.

The vacuum cleaner filter bag may also include one or more sealing elements that complement the sealing effect of the centering device.

The sealing elements may be arranged in the bag and/or between the bag and the retaining plate and/or on the retaining plate.

The sealing elements may be made of rubber and/or TPE and/or the material of the vacuum cleaner filter bag. However, they may also be made of any other material that has sufficient elasticity to provide the necessary sealing effect.

The invention further provides a vacuum cleaner bag according to claim 12, comprising a bag wall, at least one sealing element, and a retaining plate. The retaining plate comprises a base plate in which a passage opening is formed, and a centering device which extends at least partially along the edge of the passage opening and comprises at least one first spring element. When being deformed in radial direction, the spring element exerts a restoring force in the opposite direction to the deformation.

In contrast to the vacuum cleaner bag according to claim 11, in this embodiment, the at least one sealing element is not part of the retaining plate, but a separate component. The at least one sealing element may be located in the bag and/or between the bag and the retaining plate.

The bag wall, the sealing element and the centering device may each have one or more of the features described above.

Further features of the invention are explained below using the exemplary figures, where

FIGS. 1a-1c schematically show a conventional retaining plate with vacuum cleaner nozzle in reference position in top view (a), as well as in reference position (b) and under load in a radial direction (c) in sectional view

FIG. 2 schematically shows the structure of an exemplary vacuum cleaner filter bag;

FIG. 3 shows a schematic representation of an exemplary mounting plate in top view;

FIGS. 4a and 4b show a schematic diagram of an exemplary retaining plate in reference position (a) and under load in a radial direction (b) in sectional view; and

FIGS. 5a-5c show profiles of exemplary centering devices.

FIG. 1a schematically shows a conventional retaining plate 1 with a passage opening 2 and a sealing element 3 attached to the retaining plate 1 in a top view. A vacuum cleaner nozzle 4 is inserted into the passage opening 2.

FIG. 1b shows a sectional view of the retaining plate 1 with vacuum cleaner nozzle 4 in reference position. It can be seen that the sealing element 3 completely seals the vacuum cleaner nozzle 4.

FIG. 1c shows the retaining plate 1 with inserted vacuum cleaner nozzle 4 after a displacement in radial direction, e.g. due to the weight force of suction material contained in a vacuum cleaner bag, which is illustrated by the arrow pointing downwards. The displacement has created a gap 5 between the sealing element 3 and the vacuum cleaner nozzle 4, through which dust can escape from the vacuum cleaner bag into the interior of the vacuum cleaner.

FIG. 2 shows the schematic structure of an exemplary vacuum cleaner filter bag. The filter bag comprises a bag wall 6, a retaining plate 7 and an inlet opening through which the air to be filtered flows into the filter bag. The inlet opening is formed here by a passage opening 8 in the base plate of the retaining plate 7 and an aligned passage opening in the bag wall 6. The retaining plate 7 is used to fix the vacuum cleaner filter bag in a corresponding holder in a vacuum cleaner housing.

Bag wall 6 comprises at least one nonwoven layer, for example of a meltblown nonwoven or a spunbond nonwoven.

The retaining plate 7 comprises a base plate made of a thermoplastic material. For example, recycled plastic material such as recycled polypropylene (rPP) or recycled polyethylene terephthalate (rPET) can be used for the base plate.

For many plastic recyclates there are relevant international standards. For PET plastic recyclates, for example, DIN EN 15353:2007 is relevant.

The term “recycled plastics” used for the purposes of the present invention is to be understood as synonymous with plastic recyclates. For the conceptual definition, reference is made to the standard DIN EN 15347:2007.

A top view of an exemplary retaining plate, which can be used in conjunction with a filter bag as shown in FIG. 2, is shown in FIG. 3. This shows the retaining plate 7 with passage opening 8. The base plate of the retaining plate 7 is here illustrated to be schematically rectangular, but it can have any shape, in particular one which may correspond to the corresponding retaining device in the vacuum cleaner housing.

FIG. 3 also shows a centering device 9 as part of the retaining plate 7, shown here as integrally formed with the base plate of the retaining plate 7, but it can also be a separate element connected to the retaining plate 7 by gluing and/or welding. In FIG. 3, the centering device runs completely around the circumference of the passage opening 8, but it can also be limited to part of the circumference.

The centering device 9 shown in FIG. 3 comprises four spring elements 10, 11, 12, 13, which are separated from each other by cut-outs 14. In other words, in the embodiment shown in FIG. 3, the centering device 9 consists of the four spring elements 10, 11, 12, 13, but the centering device 9 can also comprise a base plate on which the spring elements are fixed, for example by gluing, screwing or welding. In this case, the spring elements may be separate elements spaced from each other, in particular they may be spaced from each other in the circumferential direction of the passage opening 8. The distances between the spring elements may be equal or different. The number of spring elements is not limited to four, but the centering device 9 always includes at least one spring element.

In FIG. 3, the spring elements 10, 11, 12, 13 are formed by deformed regions of the retaining plate 7. The deformed regions are formed by alternating elevations and/or depressions, whereby additional flat regions can be arranged between the elevations and/or depressions. In particular, the sequence of deformations repeats itself periodically, with one period forming a wave 15, e.g. if the deformed regions are formed by alternating elevations and depressions, one elevation and an adjacent depression each represent a wave 15.

In FIG. 3 the spring elements 10, 11, 12, 13 each comprise four waves 15, but the spring elements can have any number of waves 15.

In the embodiment shown in FIG. 3, the waves 15 form concentric ring structures around the passage opening 8.

FIG. 3 further shows that the arrangement of the spring elements 10, 11, 12, 13 has no rotational symmetry with respect to the passage opening 8. In particular, the spring element 10 is larger than the spring elements 11, 12 and 13, which also means that the spring force of the spring element 10 is larger than that of the spring elements 11, 12 and 13. If the retaining plate 7 is installed in a vacuum cleaner in such a way that the main load direction of is directed towards the spring element 10, the largest restoring force is achieved in this direction. In FIG. 3, this is illustrated with an arrow indicating the direction of gravity. If gravity acts in the direction of the arrow, spring element 10 is compressed the most by the displacement of the retaining plate 7. Since spring element 10 also has the strongest restoring force, this ensures that the displacement in the main load direction can be compensated.

The arrangement of the spring elements can also have n-fold rotational symmetry with respect to the passage opening 8, where n is an integer greater than 1. This is advantageous, for example, if there is no main load direction in the plane of the retaining plate 7 during operation of the vacuum cleaner. In particular, this may be the case when the axis of the vacuum cleaner nozzle 4 is substantially parallel to the direction of gravity during operation.

FIGS. 4a and 4b show a schematic sectional view through the exemplary retaining plate 7 with an inserted vacuum cleaner nozzle 4, analogous to FIGS. 1b and 1c. FIG. 4a and FIG. 4b also show a sealing element 16, which is attached to the inside of the retaining plate 7. In particular, the illustrated sealing element 16 is attached to a spring element, which can be advantageous in order to save material. The sealing element 16 can also be attached to undeformed regions of the retaining plate 7. Furthermore, sealing element 16 can completely cover the spring elements in radial direction when viewed in a top view. This is advantageous, for example, if the spring elements are separated from each other by cut-outs 14. The sealing element 16 can also be attached to the outside of the retaining plate 7.

The sealing element 16 may comprise a thermoplastic elastomer, e.g., based on polypropylene, or may consist of it. The sealing element 16 is intended to prevent or limit the escape of dust from the vacuum cleaner filter bag by sealing the area between the inner edge of the passage opening 8 and the outside of a connection nozzle of the vacuum cleaner. However, the sealing lip shown here is only optional. It is also conceivable that the bag material of the vacuum cleaner filter bag itself could be used as a sealing ring, as for example disclosed in DE 102 03 460. It is also possible to use a sealing diaphragm between retaining plate 7 and bag wall 6, as disclosed in EP 2 044 874.

FIG. 4a shows the retaining plate 7 and the vacuum cleaner nozzle 4 in reference position. It can be seen that the sealing element 16 completely seals the vacuum cleaner nozzle 4.

FIG. 4b shows the support plate 7 and the vacuum cleaner nozzle 4 under the influence of a force, illustrated by the arrow, which corresponds to the force acting on the support plate 1 in FIG. 1c. FIG. 4b shows that the spring element 10 is deformed when compared to FIG. 4a. Due to this deformation, it exerts a restoring force which is opposite to the acting force. The displacement of plate 7 and the resulting deformation of sealing element 16 is less than in the case illustrated in FIG. 1c, even though the acting force is the same. This means that there is no gap, or a smaller one, between the sealing element 16 and the vacuum cleaner nozzle 4. In other words, the sealing properties of the sealing element 16 are improved by the force acting in a radial direction.

In the situation illustrated in FIG. 4b, the forces between the spring element and the vacuum cleaner nozzle 4 act indirectly via the sealing element 16, but it is also possible that the vacuum cleaner nozzle 4 is in direct contact with the spring element and the forces act directly between these elements.

FIG. 5 shows possible designs of spring elements 10, 11, 12, 13 in profile. A wave 15, for example, can be formed by alternating U-shaped elevations and flat regions, as shown in FIG. 5a. Alternatively, they can be formed by alternating U-shaped elevations and U-shaped depressions, as shown in FIG. 5b. In this case, the entire wave has an S-profile. FIG. 5c shows an embodiment in which V-shaped elevations and depressions alternate. However, it is also possible to combine U- and V-shaped elevations with each other and/or flat regions. The elevations and/or depressions need not be pointed or rounded either, but may be flattened at their respective ends.

It is understood that features described in the embodiments above are not limited to these special combinations and are also possible in any other combination. Further, it is understood that the geometries shown in the figures are only exemplary and can also be designed in any other form.

RETAINING PLATE WITH CENTERING DEVICE

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