TECHNICAL FIELD

The present invention relates to an agitator element for a cleaner head of a vacuum cleaner, as well as to a cleaner head comprising such an agitator element, and to a vacuum cleaner comprising such a cleaner head.

BACKGROUND

A vacuum cleaner typically comprises a cleaner head having a housing defining a suction chamber. The housing is configured to be moved over a floor or other surface that needs to be cleaned while air is drawn into the suction chamber together with dust, hair, and other dirt that is thereby removed from the surface. An outlet of the housing is coupled to a motor via a wand or hose. The motor provides for the suction needed to generate the airflow through the suction chamber. In many modern vacuum cleaners, the cleaner head comprises one or more brush bars or other types of agitator elements that rotate while the housing moves over the surface to be cleaned. The agitator elements serve to detach dirt from the surface and to increase the chance that it is picked up, thereby improving the cleaning performance of the vacuum cleaner.

Typically, vacuum cleaner heads experience some degree of hair ingress during use, which means that hair can ingress into or between parts of the cleaner head. Hair can also become wound around the agitator elements which can damage the agitator elements and which can also reduce their ability to detach dirt and hair from the floor, especially if a thick layer of hair becomes wrapped around the agitator elements.

It is against this background that the present invention has been developed. SUMMARY

In a first aspect, the present invention provides an agitator element for a vacuum cleaner, wherein the agitator element has an axis of rotation which extends from a first end of the agitator element towards a second end of the agitator element and a shape which tapers from the first end of the agitator element towards the second end of the agitator element, wherein the second end of the agitator element comprises a recess, wherein the recess is configured to releasably retain a debris strand ball formed during use of the agitator element in a vacuum cleaner. The recess may extend in a direction away from the second end of the agitator element towards the first end of the agitator element.

The present invention is advantageous as the recess provides room for the debris ball to form before it is released from the brush bar to be removed to a bin by the vacuum.

Optionally the recess is open on a first side of the recess, and closed on a second side of the recess, wherein the first side of the recess is opposed to the second side of the recess. This is advantageous as it helps to encourage the debris strand ball to migrate out of the recess.

The closed side of the recess is optionally bounded by a wall which terminates in a crescent shaped surface located at the second end of the agitator element, wherein a first portion of the wall located proximate a first end of the crescent shaped end surface flares outwardly away from the axis of rotation of the agitator element. The flared surface is advantageous as it helps to encourage strands and other debris to enter the recess when the brush bar is rotated in a direction with the flared surface leading. If the brush bar is rotated in the opposite sense, the flared surface help the strand ball to migrate out of the recess.

A second portion of the wall located proximate a second end of the crescent shaped end surface may flare outwardly away from the axis of rotation of the agitator element, wherein the profile of the outward flare of the second portion of the wall is different to the profile of the outward flare of the first portion of the wall. In this example, the brush bar rotates in use such that the surface with the greater extent of flare leads and the surface with the lesser extent of flare follows. This arrangement helps to encourage strands and other debris to be swept into the recess at the side of the recess with the greater flare, and to be released from the recess at the side with the lesser flare.

In one example the recess may be located between a pair of prongs located on opposite sides of the agitator element. Optionally the prongs are asymmetric about a plane located midway between the prongs. In particular, the inner facing surfaces of the prongs may be asymmetric about the said plane. The recess may also optionally be asymmetric about a plane located midway between the prongs. In one example the prongs may be of different lengths.

The innermost surface of one or both prongs may flare outwardly away from the axis of rotation of the agitator element proximate one or both side edges of the prongs. The flared surfaces are advantageous as they help to encourage strands and other debris to enter the recess when the brush bar is rotated in a direction with the flared surface leading. If the brush bar is rotated in the opposite sense, the flared surfaces help the strand ball to migrate out of the recess. In one example the extent of outward flare may increase towards the second end of the agitator element of at least one side edge of at least one prong.

Optionally the extent of outward flare on a first side edge of a first one of the prongs is greater than the extent of outward flare on the opposite side edge of the opposite prong. In this example, the brush bar rotates in use such that the surfaces with the greater extent of flare lead and the surfaces with the lesser extent of flare follow. This arrangement helps to encourage strands and other debris to be swept into the recess at the side of the recess with the greater flare, and to be released from the recess at the side with the lesser flare. The recess optionally comprises a step configured such that a first portion of the recess on a first side is shallower than a second portion of the recess. This is advantageous as the step interrupts the recess so that the formed strand ball is more readily disturbed and less likely to reside in the recess. The step may extend in a direction between the first prong and the second prong.

Optionally a projection is located in the recess, wherein the projection extends towards the second end of the agitator element. This is advantageous as the projection interrupts the recess so that the formed strand ball is more readily disturbed and less likely to reside in the recess. The projection optionally has the form of at least a portion of a spiral curve.

The rotational sense of the spiral curve when viewed from the second end of the agitator element may correspond to the direction of rotation of the agitator element in use to help gather the strands together to form the debris strand ball. Alternatively, the rotational sense of the spiral curve when viewed from the second end of the agitator element may be opposite to the direction of rotation of the agitator element in use to help eject the debris hair ball from the recess.

In one example, the agitator element may comprise an outer surface which is continuous from the first end of the agitator element to the second end of the agitator element.

In a second aspect, the present invention provides vacuum cleaner head comprising: a housing which defines a vacuum chamber having an outlet, wherein the housing comprises a cover portion and wall portions which extend away from the cover portion; and an agitator element as described above mounted for rotation within the vacuum chamber, wherein the second end of the agitator element is located opposite to, and spaced from, a wall portion of the housing.

Optionally the agitator element is arranged within the vacuum chamber such that, in use, a first end of the axis of rotation located at the first end of the agitator element is located further from a floor surface to be cleaned than a second end of the axis of rotation located at the second end of the agitator element.

The inner surface of the wall portion located opposite the second end of the agitator element may define a first plane which may be optionally orientated at an acute angle with respect to a second plane which is orthogonal to the axis of rotation of the agitator element located at the second end of the agitator element.

The inner surface of the wall portion located opposite the second end of the agitator element may comprise a textured surface.

In one example the agitator element is cantilevered from a hub located at the first end of the agitator element.

Optionally the vacuum cleaner head may comprise two agitator heads mounted for rotation within the vacuum chamber.

In a third aspect, the present invention provides a vacuum cleaner comprising a vacuum cleaner head as described above.

Features described above in connection with the first aspect of the invention are equally applicable to the second and third aspects of the invention, and vice versa.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure l is a perspective view of an example embodiment of a vacuum cleaner;

Figure 2 is a partial cross-sectional view of the cleaner head of the vacuum cleaner of Figure 1;

Figure 3 is a partial perspective view of an end of the agitator element of Figure 2; Figure 4 is a perspective view of an alternative agitator element for the cleaner head;

Figure 5 is a perspective view of a further alternative agitator element for the cleaner head;

Figure 6 is a perspective view of a still further alternative agitator element for the cleaner head;

Figure 7 is a perspective view of another alternative agitator element for the cleaner head;

Figure 8 is a perspective view of yet another alternative agitator element for the cleaner head; and

Figure 9 is a perspective view of an alternative agitator element to the agitator element shown in Figure 8.

DETAILED DESCRIPTION

Figure 1 shows a hand-held vacuum cleaner 2 comprising a main body 4, a wand 6 and a cleaner head 20. The main body 4 comprises a separating system 10, in the form of a cyclonic separator, a motor and impeller (not visible) arranged to draw air through the separating system 10, and a power supply 12, in the form of a battery, for powering the motor. The main body 4 has a handle 14 which is gripped by a user, and a clean air outlet 16 through which air that has passed through the separating system 10 is discharged. The wand 6 is attached at one end to the main body 4 and at the other end to the cleaner head 20. The wand 6 provides fluid communication between the cleaner head 20 and the separating system 10 and supports the cleaner head 20 during use. Figure 2 shows a partial cross-sectional view of the cleaner head 20 of the vacuum cleaner 2. The cleaner head 20 has a housing 32, which defines a suction chamber 34 comprising an outlet for expulsion of air and debris towards the vacuum cleaner 2. The cleaner head 20 comprises a pair of agitator elements 22, 24 mounted for rotation about respective axes Rl, R2. The agitator elements 22 are each cantilevered from opposing sides of a hub portion 30 of the cleaner head 20 at respective first ends 26 29.

In the illustrated embodiment, the hub portion 30 is at a laterally central position with respect to the overall cleaner head 20, although this may not always be the case. For example, if the agitator elements 22, 24 have different lengths, then the hub portion 30 could be offset laterally relative to the laterally central part of the cleaner head 20. The hub portion 30 serves to rotatably support the first ends 26, 29 of the agitator elements 22, 24 and may comprise a drive housing holding a drive mechanism for rotating the agitator elements 22, 24. In an alternative embodiment, the agitator elements 22, 24 may be cantilevered from separate hubs located at the first ends 26, 29 of the agitator elements 22, 24 respectively.

The housing 32 comprises a cover portion 33 and wall portions 35 which extend away from the cover portion 33 towards a floor surface to be cleaned in use. The cover portion 33 generally extends over the agitator elements 22, 24, and the wall portions 35 generally surround the agitator elements 22, 24 in the manner of a skirt.

The cross-section of only one of the agitator elements 22 is shown in its entirety in Figure 2, and the description below is given in the context of the agitator element 22. It will be understood that the agitator element 24, and the portion of the housing 32 not shown in Figure 2, is the same as described below in respect of agitator element 22.

The agitator element 22 comprises a first end 26 and a second free end 28. In this embodiment, the agitator element 22 has a frustoconical shape which tapers from the first end 26 towards the second end 28 in a direction along the axis of rotation Rl. The cross-sectional area of the first end 26 of the brush bar 22 in a direction orthogonal to the axis of rotation R1 is consequently larger than the cross-sectional area of the second end 28 in a direction orthogonal to the axis of rotation Rl.

It should be appreciated that a portion of the agitator element 22 may not be tapered. For example, the agitator element 22 may consist of a cylindrical portion combined with a frustoconical portion. In other embodiments, the agitator element 22 may be fully cylindrical.

Referring additionally to Figure 3, the second end 28 of the agitator element 22 comprises a recess 40 located between a pair of prongs 41, 42 located opposite one another on either side of the agitator element 22.

The agitator element 22 also comprises helically wound strips of upstanding bristles 21 which extend along the agitator element 22 from the first end 26 to the second end 28. In alternative embodiments, one or both of the helical strips 21 may be augmented with, or replaced by, a flexible rubber blade or similar. The upstanding bristles may be angled towards the second end 28 of the agitator element 22.

In the example shown in Figure 2, the second end 28 of the agitator element is located opposite to, and spaced from, an end wall portion 36 of the housing 20. The end wall portion 36 is flat and configured so that it extends downwardly, in use, from the cover portion 33 towards the floor surface to be cleaned.

The agitator element 22 is arranged within the vacuum chamber 34 such that, in use, a first end of the axis of rotation Rl located at the first end 26 of the agitator element 22 is located further from the floor surface to be cleaned than a second end of the axis of rotation Rl located at the second end 28 of the agitator element 22.

The inner surface 37 of the end wall portion 36 defines a first plane Pl which is orientated at an acute angle e with respect to a second plane P2 orthogonal to the axis of rotation Rl of the agitator element 22 located at the second end 28 of the agitator element 22. As a result, the distance between the second end 28 of the agitator element 22 and the opposing end wall portion 36 towards the distal end 38 of the end wall portion 36 is greater than the distance between the second end 28 of the agitator element 22 and the opposing end wall portion 36 towards the proximal end 39 of the end wall portion 36.

The inner surface 37 of the end wall portion 36 comprises a textured surface which may be provided by an applied surface covering or coating, or which may be formed in the material of the end wall portions 36. The textured surface may be a rough surface or surface covering, and/or may comprise regular or irregular projections with the same or different forms. Example forms for the projections include, but are not limited to, demi- spherical, cylindrical, spiral, and pyramidal.

In use, the cleaner head 20 is moved over a surface to be cleaned and a vacuum is created in the vacuum chamber 34 by the motor located in the main body 4. At the same time, the agitator elements 22, 24 are rotated about their respective axes Rl, R2 by the or each agitator element drive mechanism. Typically, the agitator elements 22, 24 rotate in a direction towards a primary direction of use. For example, referring to Figure 2, if the primary direction of use of the cleaner head 20 is out of the page, then the agitator elements 22, 24 rotate in a clockwise direction about their respective axes of rotation Rl, R2 when viewed along the axes of rotation from the first to the second end of the agitator elements.

When the cleaner head 20 passes over hair or other long strands of debris, the strands tend to become wrapped around the agitator elements 22, 24. The tapered configuration of the agitator elements 22, 24 tends to cause the wrapped strands to migrate along the agitator elements towards the second, or smaller, ends where they can be removed. The prongs 41, 42 are beneficial as they help the strands to ‘fall-off the agitator elements 22, 24. It has been found that the provision of the rough surface 37 also helps to pull the strands off the agitator elements 22, 24. The strands which have migrated off the agitator elements 22, 24 tend to form debris strand balls which reside in the recesses 40 until they are of a sufficient size to be sucked from the recesses by the vacuum in the vacuum chamber 34. The rough surfaces 37 also help to cause debris strand balls to be pulled from the recesses 40 once they have reached a sufficient size.

Figure 4 shows a perspective view of an agitator element 22 having a differently shaped recess 50 to that described above and shown in Figures 2 and 3. Like reference numerals have been used to indicate like features throughout.

The agitator element 22 of Figure 4 comprises a pair of asymmetric prongs 51, 52 and an asymmetric recess 50. The prongs 51, 52, and the recess 50 are asymmetric about a plane located midway between the prongs, and about a plane passing through the midpoint of each prong 51, 52. In particular, the innermost surfaces 53, 54 of the prongs flare outwardly away from the axis of rotation R1 of the agitator element 22 to different extents such that a portion 55 of the lowermost surface 54 (in the orientation of Figure 4) located proximate a first side edge 59 of the prong 52 flares outwardly away from the axis of rotation R1 to a greater extent than a portion 56 of the lowermost surface 54 located proximate a second side edge 60 of the prong 52. Similarly, a portion 57 of the uppermost surface 53 (in the orientation of Figure 4) located proximate a first side edge 61 of the prong 51 flares outwardly away from the axis of rotation R1 to a greater extent than a portion 58 of the uppermost surface 53 located proximate a second side edge 62 of the prong 51. Thus, the extent of outward surface flare of surface portions 55, 57 is greater than the extent of outward surface flare of surface portions 58, 56 on the opposite side edge of the opposite prong respectively. In addition, the extent of outward surface flare of surface portions 55 and 57 increases towards the second end 28 of the agitator element 22.

The profiles of the innermost surfaces 53, 54 of the prongs 51, 52 described above is advantageous as the greater and lesser extents of flare of the surface portions 55, 57, 56, 58 help to encourage the debris strand ball to first form and then migrate out of the recess 50. Referring to the orientation of Figure 4, in use the agitator element 22 rotates anti-clockwise when viewed from the outer end of the axis of rotation R1 looking towards the first end 26 of the brush bar 22. Consequently, surface portions 55, 57 with the greatest amount of flare lead while surface portions 56, 58 with the lesser amount of flare follow. The greater amount of flare of the surface portions 55, 57 help to encourage hair and other strands and debris to be swept into the recess 50 where it forms into a strand ball, and the lesser extent of flare of surface portions 56, 58 help to encourage the strand ball to exit the recess 50.

It will be understood that the profiles of the innermost surfaces 53, 54 of the prongs 51, 52 may be optimised to best suit a particular application. The flare of the surface portions 55, 57 may be the same or may differ. Similarly, the flare of the surface portions 56, 58 may be the same or may differ.

Figure 5 shows a perspective view of an agitator element 22 having an alternative differently shaped recess 70 comprising a step 75 which is configured such that a first portion 73 of the recess 70 on a first side of the step 75 is shallower than a second portion 74 of the recess 70 on a second side of the step 75. The step 75 extends in a direction between the prongs 71, 72. The surface flare features described above with respect to Figure 4 are also present in the embodiment of Figure 5. However, in another example embodiment, the extent of flare may be symmetrical between the prongs 71, 72.

The step 75 is shown in Figure 5 as being midway between he prongs 71, 72. In an alternative embodiment, the step 75 may be offset from the centre.

The differing depths of the portions 73, 74 of the recess 70 on either side of the step 75 described above is advantageous as this arrangement helps to encourage the debris strand ball to migrate out of the recess 70. Specifically, the step 75 interrupts the recess 70 so that the formed strand ball is more readily disturbed and less likely to reside in the recess 70. Figure 6 shows a perspective view of an agitator element 22 having another alternative shape of recess 80 which is open on a first side 81 of the recess 80, and closed on a second side 82 of the recess 80 opposed to the first side 81 of the recess 80.

In this example, the closed side 81 of the recess 80 is bounded by a wall 83 which terminates in a crescent shaped surface 84 located at the second end 28 of the agitator element 22. A first portion 85 and a second portion 86 of the wall 83 located proximate a first end 87 and a second end 88 of the crescent shaped end surface 84 respectively flare outwardly away from the axis of rotation R1 of the agitator element 22. In the embodiment shown the first portion 85 of the wall 83 flares outwardly to a greater extent than the second portion 86 of the wall 83. In another example, the extent of flare of the first 85 and second 86 portions may be the same or reversed.

The closed sided recess 80 is advantageous as this arrangement helps to encourage the debris strand ball to migrate out of the recess 80 by interrupting the recess 80 so that the formed strand ball is more readily disturbed and less likely to reside in the recess 80

Figure 7 shows a perspective view of an agitator element 22 having a further alternative shape of recess 90 comprising a projection 91 which extends from the base of the recess 90 towards the second end 28 of the agitator element 22. In this example the projection is in the form of a domed nipple. However, the projection may take any suitable form such as cylindrical boss or flat plate. The recess 90 is the same in all other respects as the recess 50 described above in relation to Figure 4.

In Figure 7 the projection 90 is shown in a position at the centre of the recess 90. In an alternative embodiment, the projection 90 may be offset from the centre in any direction. One or more projections 90 may also be used in the recesses 70 or 80 described above in relation to Figures 5 and 6. The use of a projection 91 is advantageous as it helps to encourage the debris strand ball to migrate out of the recess 90 by interrupting the recess 90 so that the formed strand ball is more readily disturbed and less likely to reside in the recess 90.

Figures 8 and 9 show a perspective views of alternative forms for the projection. In Figure 8 a pair of projections 92, 93 are located in the recess 90, and in Figure 9 a pair of projections 94, 95 are located in the recess 90. Each of the projections 92, 93, 94, 95 has the form of a portion of a spiral curve.

In the embodiment of Figure 8, the rotational sense of the pair of spiral curves 92, 93 is opposite to the direction of rotation of the agitator element 22 in use. This helps to eject the debris hair ball from the recess 90. In the embodiment of Figure 9, the rotational sense of the pair of spiral curves 92, 93 corresponds to the direction of rotation of the agitator element 22 in use. This helps to gather the strands together to form the debris strand ball.

In a further alternative embodiment (not shown) the length of the prongs may be different.

For all of the agitator elements 22 described above, the outer surface of the agitator element 22 is continuous from the first end 26 of the agitator element 22 to the second end 28 of the agitator element 22. In An alternative, second end 28 of the agitator element 22 comprising the recess 40, 50, 70, 80, 90 may be a separate element which attaches to the main body of the agitator element 22.

Any of the agitator elements 22 described above may be used alone or in matched or unmatched pairs in the cleaner head 20.