FIELD OF THE INVENTION

The invention relates to a vacuum cleaner having a dust bag compartment.

BACKGROUND OF THE INVENTION

DE8506818 discloses a filter arrangement in a vacuum cleaner, in which a paper filter bag in operation has a concertina- or accordion-like folding, characterized in that the paper filter bag is inserted directly into a receiving space having a surface formed by elevations and depressions, and the paper filter bag surface is dimensioned according to the larger surface of the receiving space as result from the elevations and depressions.

Dust bag compartments of vacuum cleaners often have ribs to create a distance between the dust bag and the wall of the dust bag compartment. These ribs allow for air to move between the dust bag and the wall in directions dictated by the ribs in its path from the dust bag towards an inlet of the fan compartment.

SUMMARY OF THE INVENTION

It is, inter alia, an object of the invention to provide an improved vacuum cleaner. The invention is defined by the independent claims. Advantageous embodiments are defined in the dependent claims.

The invention is based on the recognition that if air can only move in directions dictated by the orientation of the ribs, the air cannot directly move to the fan inlet. This leads to resistance, and thus to a loss in suction power. Additional, some locations in the dust bag compartment may not have ribs at all, at which locations there is no airflow possible through the bag, and the bag material is not used at all to separate and store dust.

By providing a wall of the dust bag compartment with a three-dimensional open structure for creating a distance between a dust bag and the wall, and allowing air to move substantially omnidirectionally in and through the three-dimensional open structure, the resistance caused by the prior art configuration will no longer occur, and suction power is optimally used to clean the floor. The three-dimensional open structure may be arranged to allow air to move through the three-dimensional open structure until the air reaches an outlet of the dust bag compartment. Preferably, the three-dimensional structure includes a spacer fabric having a first two-dimensional knit fabric layer and a second two-dimensional knit fabric layer, which are interconnected via knitted spacing threads. Preferably, the three- dimensional structure is provided at least at side and bottom walls of the dust bag

compartment, extending until an inlet of a fan compartment. Preferably, a thickness of the three-dimensional structure is between 5 and 25 mm.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE DRAWING

Fig. 1 illustrates an embodiment of the invention.

DESCRIPTION OF EMBODIMENTS

To ensure optimal airflow from all locations of the dust bag towards the motor inlet location in the dust bag compartment, the ribs on the walls of the dust bag compartment, which allow airflow in one direction only, are replaced or supplemented by an open structure, so that an omnidirectional air movement is possible at each point of the three-dimensional open structure. This open structure allows the air to exit the bag at all locations and move around outside of the bag towards the motor inlet via the path with lowest resistance. The open structure should be stiff enough to ensure that it stays open even under weight of a filled dust bag.

In the embodiment of Fig. 1, a three-dimensional structure 3D-S is placed against a wall W of a dust bag compartment. A dust bag (not shown) can be placed to the left of the three-dimensional structure 3D-S. While Fig. 1 only shows part of one wall W provided with the three-dimensional structure 3D-S, several or all walls of the dust bag compartment may be provided with the three-dimensional structure 3D-S. As illustrated by the arrows in Fig. 1, the three-dimensional structure 3D-S is arranged to allow air leaving the dust bag to flow into, inside and through the three-dimensional structure 3D-S until it leaves an outlet of the dust bag compartment to enter a fan compartment (not shown) of the vacuum cleaner, usually through a fan inlet filter (not shown).

A suitable 3D open material or structure can be a textile material as marketed by Miiller Textil GmbH as 3mesh, and described in US2016273137, which discloses a spacing knit fabric with first and second two-dimensional knit fabric layers, which are interconnected via knitted spacing threads. The first two-dimensional knit fabric layer has openings formed by a plurality of stitches in each case. Threads of a first thread system, which forms the first two-dimensional knit fabric layer, are connected to each other solely by mutual intertwining. Channels are formed between the first and the second two-dimensional knit fabric layers that are free from spacing threads. The threads of a second thread system, which forms the second two-dimensional knit fabric layer, are connected to one another by intertwining and by at least partial fusion.

The properties that make this textile material suited for the intended purpose in dust bag compartments of vacuum cleaners, are the combination of extreme openness inside and through the textile material combined with high stiffness in the thickness direction. So air can easily flow in and through this material, but the material is stiff enough in the thickness direction to keep this area open even with the load of a filled dust bag.

An alternative suitable 3D material or structure is marketed by Bonar as 3D Mats. In yet another embodiment, the walls of the dust bag compartment are provided with a large plurality of pillars (e.g. between 0.5 and 2 per cm ² , and having a thickness of e.g.

between 1 and 3 mm, preferably with a blunt top so as to prevent the dust bag from being damaged) that create a distance between the dust bag and the wall, while allowing air to move into and through the space defined by the pillars in a plurality of directions.

Instead of (or additional to) ribs on the walls of the dust bag compartment, the walls are covered with the open structure. Advantageously, the open structure is present up till a fan inlet structure at an outlet of the dust bag compartment. This ensures that the air that moves through the open material can reach the fan inlet filter with minimal thresholds. The thickness of the open structure is typically around 5-25 mm. If the thickness is less, the resistance for the air increases, while if it is more, the space it takes will make the entire vacuum cleaner more bulky.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. The word "having" does not exclude the presence of elements or steps other than those listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.