Vacuum cleaner with filter cleaning means

Technical Field

The present invention relates to a hand held vacuum cleaner comprising a housing, a dust container, a motor fan unit and a filter unit.

Background Art

Vacuum cleaners are commonly used in households for removing dust and debris from various surfaces, and today it is essential that the vacuum cleaner be easy to use, easy to clean and versatile in respect of fields of application.

Generally, a vacuum cleaner has a filter for removing dust from dust laden air flowing through the vacuum cleaner. After some time of usage dust adheres to the filter surface which leads to a pressure drop and reduced vacuum cleaning efficiency. Thus, cleaning of the filter is necessary to remove the particulate matter, such as dust, hair and fibers, from the filter.

In case of a clogged filter, it is also common to replace the filter with a new one for regaining vacuum cleaning efficiency.

<patcit id="pcit0001" dnum="WO2004069021A"><text>WO 2004/069021</text></patcit> discloses a hand held vacuum cleaner having housing incorporating a motor fan unit. A dust container is connected to the housing, and when the vacuum cleaner is operated, dust laden air flows through an inlet, into the dust container, through a filter for trapping dust, and thereafter past the motor fan unit and out through air outlets. After operation fine dust is clogged to the filter, and sucked up debris is trapped in the dust container.

The dust container is emptied by letting out trapped debris through a dust outlet opening. Another way of emptying the dust container involves removing the dust container, removing the filter from the dust container and letting out debris through a hole previously covered by the removed filter. The filter is cleaned by manually shaking or brushing the filter, or by vacuum cleaning the filter with another vacuum cleaner.

The filter cleaning process for the described vacuum cleaner is rather cumbersome. Moreover, dust removed from the filter is often uncontrollably spread to the surroundings.

In <patcit id="pcit0002" dnum="US2558429A"><text>US 2,558,429</text></patcit> a vacuum cleaner is disclosed having a filter for separating dirt from incoming dirt laden air. The filter comprises an outer pervious cylindrical wall and an inner frusto-conical wall. The outer cylindrical wall is held in a taut condition by a first spring-loaded mechanical arrangement and the inner frusto-conical wall is held in taut condition by a second spring-loaded mechanical arrangement. By moving the mechanical arrangements against the respective load direction and releasing the springs, the filter will move back to the taut condition, shaking dirt from the filter.

Another dust collector arrangement for a vacuum cleaner is disclosed in <patcit id="pcit0003" dnum="US971013A"><text>US 971,013</text></patcit>, wherein the filter is made of a fabric that is held taut by a rod and spring in a circular cone shaped form inside the dust collector arrangement. The fabric can be articulated in order to remove dust from it by means of a crank and agitator wheel for reciprocating the rod against the bias of the spring.

Summary of the Invention

It is an object of the present invention to provide an improvement of the above techniques and prior art.

These and other objects as well as advantages that will be apparent from the following description of the present invention are achieved by a hand held vacuum cleaner having the features of appended claim 1. Preferred embodiments are defined in the dependent claims.

The hand held vacuum cleaner according to the invention is advantageous since the dust removing means cause adhered dust to fall off the filter when the dust removing means collapses and expands the filter body.

The dust removing means may be configured to be manually operated, which provides a simple structure allowing a user to operate the dust removing means.

The dust removing means may further comprise an elastic element which continuously exerts a force on a portion of the filter unit, for the purpose of providing an effective way of expanding the flexible filter body.

The dust removing means may comprise a rod connected to a bottom portion of the filter unit, and the rod may be movable in a direction from said portion of the filter unit to an opposite portion of the filter unit. This embodiment is cost efficient in terms of production and contributes to a low overall cost for the implementation of the present invention.

The vacuum cleaner according to the invention may comprise an elastic element which continuously exerts a force on the rod for expanding the flexible filter body and for providing efficient cleaning of the filter.

The filter unit may comprise an attachment member for attaching the filter unit to any of the housing and the dust container, which provides a fast and user friendly attachment of the filter unit.

The aforementioned attachment member may support the dust removing means, and the filter unit and the dust removing means may form an integrated and exchangeable filter assembly. These arrangements provide for a fast, combined and automated manufacturing process for the filter and/or the dust removing means, as well as convenient handling of the filter unit.

The attachment member and the flexible filter body may be integrated which is advantageous since a more efficient filter manufacturing process is facilitated.

The flexible filter body may be essentially tubelike with one closed end and one open end opposite the closed end, for providing an efficient dust trapping filter shape.

The flexible filter body may have a sleek surface facing the interior of the dust container, which allows, for example, hair and fibers to more easily fall off the filter.

The filter unit may comprise a coarse pre-filter body at least partially encompassing the flexible filter body, which allows coarse particles such as fibers and hair to be trapped by the coarse filter, while the flexible filter body which is arranged downstream of the coarse filter body traps finer particles of dust.

The coarse pre-filter body may have an opening for conveniently letting out dust when cleaning the filter unit, and the flexible filter body may have a flexible cleaning and/or sealing part attached to a portion of the flexible filter body for closing the opening of the coarse pre-filter body. The cleaning/sealing part assists in removing dust by scraping the interior of the pre-filter body during filter cleaning, and provides an efficient seal between the pre-filter and particle-filter during operation of the vacuum cleaner.

The vacuum cleaner according to the invention may further comprise means for swirling the incoming air around the filter unit. This is advantageous since vacuumed dust is more evenly adhered around the circumference of the filter, which prevents some parts of the filter to be excessively clogged, which would lead to a substantial decrease of air flow through the vacuum cleaner.

According to the invention, any one of the housing, the dust container and the filter unit may comprise at least one air flow guiding vane for generating the swirling or cyclonic effect described above.

Any one of the dust container and filter may comprise a dust-trapping rib for causing dust to be trapped near a desired part of the filter unit, which aids in building up an even distribution of dust around the filter body.

The term "hand held vacuum cleaner" incorporates small vacuum cleaners intended for vacuum cleaning small surfaces. During operation the hand held vacuum cleaner is, as one unit, continuously carried or continuously moved over a surface being vacuum cleaned.

It should be noted that the term "hand held vacuum cleaner" incorporates stick vacuum cleaners.

Brief Description of the Drawings

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying schematic drawings, in which <ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">Fig. 1</figref> is a perspective view of a hand held vacuum cleaner,</li><li><figref idref="f0002">Fig. 2</figref> is a cross-sectional view of the hand held vacuum cleaner of <figref idref="f0001">Fig. 1</figref>,</li><li><figref idref="f0003">Fig. 3</figref> is a cross-sectional view of a filter unit according to a first embodiment,</li><li><figref idref="f0003">Fig. 4</figref> is a side view of the filter unit of <figref idref="f0003">Fig. 3</figref>,</li><li><figref idref="f0003">Fig. 5</figref> is a view of the filter unit of <figref idref="f0003">Fig. 3</figref> in a contracted state,</li><li><figref idref="f0004">Fig. 6</figref> is a cross-sectional view of a filter unit according to a second embodiment,</li><li><figref idref="f0004">Fig. 7</figref> is a view of the filter of <figref idref="f0004">Fig. 6</figref> in a contracted state,</li><li><figref idref="f0004">Fig. 8</figref> is a cross-sectional view of a filter unit according to a third embodiment, and</li><li><figref idref="f0005">Fig. 9</figref> is an exploded view of a hand held vacuum cleaner with a filter unit incorporating swirling means.</li></ul>

Detailed Description of Embodiments

With reference to <figref idref="f0001">Figs 1</figref>, <figref idref="f0002">2</figref> and <figref idref="f0005">9</figref> a hand held vacuum cleaner 1 is illustrated. The vacuum cleaner 1 comprises a housing 10 having a handle 2, an on/off-switch 3 and an inlet 4 for suction of dust laden air. The suction is generated by means of a motor fan unit 6 arranged in the housing 10. When the vacuum cleaner 1 is operated, air flows from the inlet 4 of the vacuum cleaner 1, into an inlet opening 8 of a dust container 7, through a filter unit 11, past the motor fan unit 6, and finally the air exits the vacuum cleaner 1 through outlets 5.

The motor fan unit 6 is typically powered by batteries 9 arranged in the handle 2 and is turned on or off by means of the on/off-switch 3. Preferably the batteries 9 are rechargeable and preferably the housing 10 comprises a power-inlet and electrical circuits (not shown) for reloading the batteries 9.

As described above, dust laden air flows through the filter unit 11 during operation and thereby the air is filtered by the filter unit 11 which traps dust, fibers, hair, sand and other particles. Some of the sucked up particles adhere to the filter unit 11, but most are trapped in a lowermost part of the dust container 7. The dust container 7 is emptied, for example, by opening a lid 12 belonging to the dust container 7 and by allowing the dust to exit the lid opening, or by removing the dust container 7 from the housing 10 and allowing dust to escape from an opening 13 of the dust container 7.

With reference to <figref idref="f0003">Figs 3 and 4</figref>, a filter unit 11 according to a first embodiment is illustrated. The first embodiment does not show all features of claim 1. The filter unit 11 comprises an air permeable and flexible filter body 14 having the form of a tubular bag with its open end, or top portion 15, integrated with a filter attachment member 17. A dust removing means 29 comprising a rod 22 and a spring 28 is arranged inside the filter body 14, and en end portion 23 of the rod 22 is connected to a closed portion 16 of the filter body 14. The rod 22 is supported by a support part 18 integrated with the filter attachment member 17 via at least one arm 19. Preferably the support part 18 forms a hole for the rod 22. The filter body 14 is straightened by a biasing force applied by the spring 28 which is arranged around the rod 22 between a rod protrusion 25 and the support part 18 of the attachment member 17.

The attachment member 17 comprises holes 20 that are configured to receive therethrough corresponding pegs (not shown) that extend from the housing 10 or from the dust container 7 in order to form a bayonet joint. Resilient sealing members 26, 27 are arranged on the attachment member 17 for providing an air tight seal between the housing 10 and/or the dust container 7.

The attachment member 17 may also be connected by connecting the dust container 7 to the housing 10 and therebetween fitting and pressing the attachment member 17, or the attachment member 17 may be attached to the housing 10 or the dust container 7 by an interference fit or snap fit associated with the respective connecting part.

Preferably, the filter unit 11 is attached to the dust container 7 and when the filter unit 11 is to be cleaned the dust container 7 is removed from the housing 10 with the filter unit 11 still attached. Subsequently a top portion 24 of the rod 22 is moved in the direction of the arrow D for collapsing and expanding the filter unit 11, or more specifically, contracting and straightening the flexible filter body 14 as illustrated in <figref idref="f0003">Fig. 5</figref>. During this operation dust falls off the filter unit 11 and, since it is still attached to the dust container 7, into the dust container 7 without spreading dust to the surroundings. Thereby, the filter unit 11 is cleaned.

The outer surface of the filter body 14, i.e. the surface facing the interior of the dust container 7, is preferably sleek for preventing hair and fibers from adhering to the filter body 14. Any known filter material with a sleek surface may be used for manufacturing the filter body 14.

With reference to <figref idref="f0004">Fig. 6</figref> a filter unit 11 according to a second embodiment is illustrated. The filter unit 11 comprises an air permeable and flexible fine particle-filter body 32 having the form of a tubular bag with its open end, or top portion 36, integrated with a filter attachment member 17. A flexible cleaning and/or sealing part 33 is attached to a closed portion 34 of the particle-filter body 32. The filter unit 11 further comprises a coarse pre-filter body 30 which has an opening 31 in an end portion, encloses the particle-filter body 32 and is connected to the attachment member 17. It should be noted that the coarse pre-filter body 30 filters large particles such as hair and fibers, while the particle-filter body 32 filters smaller particles that pass through the coarse filter 30.

Preferably the coarse pre-filter body 30 is detachable from the attachment member 17, and the coarse filter body 30 may incorporate a separate attachment member (not shown) for attachment to any of the attachment member 17, the housing 10 and the dust container 7.

A dust removing means 29 comprising a rod 22 and a spring 28 is arranged inside the particle-filter body 32, and the inner portion of the rod 22 is connected to the closed portion 34 of the particle-filter body 32 in a manner corresponding to the filter according to the first embodiment. The spring 28 presses the cleaning/sealing part 33 towards the lower part of the coarse pre-filter body 30 and thus seals the opening 31 during operation of the vacuum cleaner 1.

The filter unit 11 according to the second embodiment is attached to the dust container 7 or the housing 10 in a manner similar to the attachment of the first embodiment of the filter unit 11. When the filter unit 11 is to be cleaned the dust container 7 is removed from the housing 10 with the filter unit 11 still being attached. The top portion 24 of the rod 22 is then moved in the direction of the arrow D for collapsing and expanding the filter unit 11, or more particularly, contracting and straightening the particle-filter body 32 as illustrated in <figref idref="f0004">Figs 6-7</figref>. During this operation dust falls off the particle-filter 32, out through the opening 31 and into the dust container 7.

If particles of dust are adhered to the interior of the pre-filter 30, the interior may be scraped by the cleaning/sealing part 33. To facilitate this operation there is an optional clearance between the filter attachment member 17 and the rod 22 to allow slight tilting of the rod along direction T.

<figref idref="f0004">Fig. 8</figref> illustrates a filter unit 11 according to a third embodiment. The third embodiment does not show all features of claim 1. The filter unit 11 comprises a spring 37 arranged inside the filter body 14 to support the filter body 14. The spring 37 is at one end connected to a bottom portion 16 of the filter body 14 and is at its other end connected to the attachment member 17. Preferably the spring 37 has a conical shape corresponding to the straightened shape of the filter body 14, as illustrated in the figure. The spring 37 "fills" the inner space defined by the filter body walls.

The rod 22 of the third embodiment may be omitted and replaced by a weight (not shown) arranged in a bottom portion 16 of the filter body 14. In this case the filter unit 11 is to be shaken for contracting and straightening the filter body 14. Such a weight may be used in any combination of the first and second embodiment.

The spring 37 according to the third embodiment may also be combined with any of the filters according to the first and second embodiment. The spring 28 of the second embodiment may, of course, be omitted to provide yet another embodiment where the spring 37 according to the third embodiment is arranged within the particle-filter body 32, and where the spring 37 is connected to the bottom portion 34 of the particle-filter body 32 and to the attachment member 17. Of course, the rod 22 of the second embodiment may be omitted and replaced by a weight (not shown) arranged in a bottom portion 34 of the particle-filter body 32.

With reference to <figref idref="f0002">Figs 2</figref> and <figref idref="f0005">9</figref>, the filter comprises a radial wall 40 for preventing dust from exiting through the opening 8 of the dust container 7 when the vacuum cleaner 1 is held with its opening 4 in an upward direction. An air-flow guiding vane 41 is arranged on the exterior of the filter unit 11 for creating an effect where air is swirled around the filter unit 11 during operation. Several air-flow guiding vanes may be arranged, and the vanes may also be arranged on the interior of the dust container 7 or on the housing 10. A support frame 42 may also be arranged to provide predetermined outer boundaries for the filter unit 11.

To cause dust to get stuck between the filter unit 11 and the dust container 7, a rib (not shown) is integrated with the filter unit 11 and extends radially towards the dust container 7.

A suitable known material is selected for the filters bodies described above, such as a plastic material for the coarse pre-filter 30 and a fiber or web-based material for the particle-filter 14, 32.

The filter body or bodies and filter attachment member are integrated, for example, by bonding, gluing, melting or sewing the filter body to a surface of the attachment member, by enclosing the open end of the filter body in the attachment member, by clamping or melting the attachment member to the filter body. Preferably the filter body and attachment member are circular as illustrated in the figures. However, any of the filter body and attachment member may, for example, be rectangular, triangular or have any other suitable shape.

The attachment member may have any suitable shape for attachment to the dust container and for support of the dust cleaning means and may, for example, comprise a disc with attachment holes and a support hole for the cleaning means. Preferably the attachment member is extruded, and preferably made of a plastic material such as polyethylene or any other similar material.

The spring may be replaced by a suitable elastic element that will provide a corresponding function. It is also possible to connect an elastic element, such as a spring or a rubber string, to the attachment member and the top portion of the rod.

The dust container may be an integrated part of the vacuum cleaner, and the inlet of the vacuum cleaner may comprise the dust container inlet.

Furthermore, the described spring is only one example of means for straightening the respective filter bodies. Other means for straightening the filter comprise an interference fit or a snap-in fitting between the rod and the filter attachment member, since this would fix the rod to the attachment member and thus provide a desired, straightened shape of the filter body. When the filter is to be cleaned, or the rod reciprocated, the interference is manually overcome by a user, or the snap-in fitting is opened by the user.

Another way of straightening the respective filter bodies comprises arranging a part of the housing, such as a protection element for the motor fan unit, to continuously exert a pressure on the top portion of the rod when the housing and the dust container are connected.

According to particular aspect of this concept, an exchangeable filter unit for a vacuum cleaner is provided, which filter comprises a flexible filter body integrated with a filter attachment member, and dust removing means configured to collapse and expand the flexible filter body in response to a force applied to the dust removing means.

The exchangeable filter unit may incorporate any of the embodiments of the filter and dust removing means of the vacuum cleaner described above.