The cleaner head of a vacuum cleaner comprises a downwardly directed dirty air inlet through which dirty air is sucked into the vacuum cleaner. A brush bar is supported in the dirty air inlet so that it partly protrudes from the inlet and is driven by a motor via a drive belt so that it rotates within the inlet. The brush bar comprises an elongate cylindrical core from which bristles radially extend along its length. Rotation of the brush bar causes the bristles to sweep along the surface to be cleaned, for example a carpet, agitating the fibres of the carpet to loosen dirt and dust and picking up debris. The suction of air causes air to flow around the brush bar and underneath it into the fibres of the carpet to help lift the dirt and dust from the carpet and into the dirty air inlet and hence into the dust separation chamber of the vacuum cleaner via an inlet passage.

The bristles are mounted directly onto the cylindrical core of the brush bar and the length of the bristles is substantially less than the diameter of the central core.

Typically, the cylindrical brush bar will have a diameter of 30-40mm and the bristles will have a length of 5-15mm. The bristles are mounted directly, normally in a helical formation, onto the cylindrical core in clusters at regular intervals around the entire circumference of the cylindrical core and along its entire length or the majority thereof.

Due to the size of the cylindrical core the space defined by the dirty air inlet is substantially filled by the core and there is therefore very little space within the dirty air inlet through which the air can pass. Also, the size of the core relative to the length of the bristles limits the passage of air beneath the brush bar and into the carpet. This diminishes the cleaning efficiency of the vacuum cleaner. Also due to the limited space within the dirty air inlet, there is a substantial risk of clogging within the cleaner head, particularly around the brush bar.

As mentioned above, the bristles are usually set in a helical formation.

Therefore, in areas of the dirty air inlet in which the brush bar is located close to the walls of the air flow path, air flows around the brush bar along the path of the helix before being directed to the dust separation apparatus via the inlet passage. This unnecessarily lengthens the path length of the true airflow within the vacuum cleaner.

The cleaner head of the vacuum cleaner is freely rotatably mounted on the main body of the vacuum cleaner, which houses the motor and dust separation apparatus. In use, the vacuum cleaner is moved over the surface to be cleaned, e. g. a carpeted surface.

The cleaner head, therefore,"floats"over the surface collecting dust and dirt via the dirty air inlet. However, the cleaner head may not maintain contact on all sides of the dirty air inlet when the vacuum cleaner is used on carpets or floor coverings of different pile depths. Some suction may be lost.

Furthermore, in use, the vacuum cleaner is moved backwards and forwards by the user over the surface to be cleaned. Due to the action of the user in dragging the cleaner back towards them, the cleaner head can be tilted backwards so that the mouth of the dirty air inlet is lifted from the surface to be cleaned particularly when it is moved over deep pile carpets. Therefore, maximum suction is not always maintained and the vacuum cleaner may not clean at maximum efficiency.

Furthermore, the tilt of the main body of the vacuum cleaner to the cleaner head may cause the dirty air inlet to be lifted from the surface to the cleaned. Therefore maximum suction is not always maintained.

The present invention seeks to provide apparatus having a better airflow within the cleaner head hence providing improved cleaning efficiency of a vacuum cleaner.

According to the present invention there is provided a brush bar for a vacuum cleaner comprising a central core, at least one flange extending radially from the central core and a pluality of bristles, the bristles being mounted on the at least one flange so that the bristles are spaced from the central core, characterised in that the or each flange extends radially outwardly from the central core to a distance more than the diameter of the central core.

Since the bristles are mounted on a flange and spaced from the core of the brush bar, more space is provided in the dirty air inlet which helps to prevent clogging and to improve the air flow within the dirty air inlet and hence to improve the cleaning efficiency of the vacuum cleaner. Furthermore, since the brush bar is smaller than conventional brush bars, the overall weight of the brush bar and hence the cleaner head of the vacuum cleaner, is reduced. Reduced weight of the cleaner head allows the cleaner head to"float"with more sensitivity on a carpet to be cleaned.

In a preferred embodiment, the or each flange extends radially outwardly from the central core to a distance 1.3 to 2.2 times the diameter of the central core.

Preferably, the at least one flange extends along the length of the central core.

The brush bar may comprise two diametrically opposing flanges which, in a preferred embodiment, extend along the length of the central core in the form of a helix, or a reverse helix.

A reverse helix is formed by a first helix rotating in one direction and extending along a part of the central core and a second helix rotating in the opposite direction along the remainder of the central core. With this arrangement the air flow around the brush bar is directed towards the centre of the brush bar and into the vicinity of the inlet passage which carries the dirty air into the interior where the dust separation apparatus is located. This minimises any unnecessary elongation of the true airflow path within the cleaner.

The central core of the brush bar preferably comprises a hollow, metal or composite carbon fibre tube over-moulded with a plastics or rubber material.

Preferably, the hollow tube is formed of aluminium and is over-moulded with a plastics material. More preferably, the at least one flange is moulded integrally with the over- moulding of the metal tube.

The brush bar above may be incorporated in a cleaner head for a vacuum cleaner. The cleaner head comprises a housing having an inlet for dirty air, the housing supporting the brush bar. In a preferred embodiment, the housing has an inlet portion, the inlet portion defining a dirty portion having a cradle portion mounted in the dirty air inlet and being rotatable with respect to the inlet portion.

The rotatable movement of the cradle portion with respect to the inlet portion of the cleaner head ensures that the dirty air inlet remains in contact with the surface to be cleaned on all sides of the brush bar. Therefore, even during the backward movement of the vacuum cleaner, towards the user, the dirty air inlet maintains contact, improving the cleaning efficiency even during the backward stroke. The dirty air inlet also remains in contact with the surface to be cleaned irrespective of the pile depth.

Preferably, the cradle portion is sealingly mounted in the dirty air inlet to prevent the ingress of air between the cleaner head casing and the cradle portion.

The inlet portion may support a plurality of rollers for contacting the surface to be cleaned to aid movement of the cleaner head over the surface to be cleaned.

Further, the housing of the cleaner head may comprise a sole plate fastened by a quick-release mechanism, for example by means of a plurality of quarter-turn screws or by snap-fitting clips. Therefore, the sole plate can be easily removed to provide access to the inlet passage to clear any blockages. The sole plate may be integral with the inlet portion and cradle. Therefore, removal of the sole plate also removes the dirty air inlet cradle and brush bar to give access to the interior of the cleaner head making it easier to clear any blockages and for maintenance, for example replacement of the brush bar. At least a part of the sole plate may be transparent so that any blockages are clearly visible.

An embodiment of the invention will now be described and fully explained with reference to the accompanying drawings, wherein: Figure 1 is a perspective view of a brush bar according to the present invention; Figure 2 is a side view of the brush bar of Figure 1 with a part of an end section of the brush bar cut away; Figure 3 is a section though the brush bar of Figure 2 taken along the line A-A; Figure 4 is a side view of a cleaner head of a vacuum cleaner according to the invention; and Figure 5 is an underside view of the cleaner head of a vacuum cleaner according to the present invention.

With reference to Figures 1 to 3, the brush bar according to the present invention will be described in more detail.

The brush bar 1 comprises a central core 8 formed of an inner metal (aluminium) tube 6 over-moulded with a layer 7 of plastics or rubber-like material. The central core 8 surrounds a spindle 3. The central core 8 (over-moulded tube) is fitted between a pair of bearings 5 so that the over-moulded tube 8 is freely rotatable with respect to the spindle 3.

The central core 8 further comprises at each end thereof an enlarged portion 9 which houses one of the bearings 5 to protect it from dirt and dust. Each enlarged portion 9 is formed of moulded plastics or rubber-like material and is integrally formed with the over-moulded layer 7. Each enlarged portion 9 comprises an end disc 11 having a central aperture 12. The end of the spindle 3 protrudes beyond the disc 11 through the aperture 12 so that the bush bar 1 can be fitted into the dirty air inlet of a vacuum cleaner as shown for example in Figures 4 and 5.

Towards one end of the over-moulded tube 8 is a pulley 13. The pulley 13 is located between two discs 15 and is fitted to the over-moulded tube 8 so that when a drive belt of a motor is fitted around the pulley 13 the over-moulded tube 8 can be rotated with respect to the spindle 3 by means of the drive belt. The pulley 13 can also be integrally moulded with the over-moulded layer 7.

The brush bar 1 further comprises a pair of flanges 17 extending radially from the over-moulded tube 8 along its entire length (except where the pulley 13 is located) at a distance 1.3 to 2.2 times the diameter of the central core 8. The flanges 17 are integrally moulded with the layer 7 of plastics or rubber-like material. They are located diametrically opposite each other and are dimensionally similar.

Each flange 17 is arranged in a helical pattern to form a reverse helix along the length of the over-moulded tube 8. The reverse helix is formed by a first helix in which the flanges 17 are rotated or twisted in a first direction along one half of the over- moulded tube 8 and a second helix in which the flanges are rotated in the opposition direction along the other half. Each helix rotates the flanges through 180°. The first helix and second helix are separated from each other by a disc 18 which helps to reinforce and strengthen the flanges 17. The diameter of the end discs 11 and discs 15 and 18 is the same and corresponds to the distance between the opposite edges of the flanges 17.

Bristles 19 are fixed along the outer edge of each flange 17 along the length of the brush bar 1. The bristles 19 are fixed in clusters, each cluster comprising a plurality of bristles 19. The bristles 19 are fixed to the flanges 17 by folding each cluster in two, placing them into a corresponding hole 20 in each flange 17 and stapling the bristles 19 into the base of the hole 20. The holes 20 can be formed by moulding, drilling or any other suitable method.

At intervals, approximately one third of the distance between the end discs 11, each flange 17 has a flattened area 21. This area 21 has no bristles and corresponds to the position of reinforcement bars 23, shown in Figure 5, of the housing surrounding the dirty air inlet of the cleaner head of the vacuum cleaner and prevents unnecessary drag on the brush bar by the reinforcement bars 23.

With the arrangement described above, the bristles are held spaced from the central core 7 by means of the pair of flanges 17. In this way, more space is provided within the dirty air inlet to help prevent clogging and to improve the airflow in the dirty air inlet. Furthermore, the reverse helix directs the air towards the centre of the brush bar into the inlet passage within the cleaner head, thus improving the efficiency of the vacuum cleaner. The reduced size of the central core and the use of an over-moulded aluminium tube helps to reduce the overall weight of the vacuum cleaner.

A cleaner head 31 for a vacuum cleaner 100 incorporating a brush bar as described above is shown in Figures 4 and 5. The cleaner head 31 is freely rotatably attached to the main body 33 of a vacuum cleaner via a motor casing 34. The main body 33 of the vacuum cleaner houses the dust separating apparatus (not shown) for example a dust bag, cyclonic separator etc. A pair of wheels 35 are mounted on the motor casing 34 at the base of the main body 33.

The cleaner head 31 comprises a dirty air inlet 37 located at the forward end of the cleaner head 31 and facing downwardly so that, in use, the dirty air inlet 37 rests on the surface to be cleaned. The brush bar 1 is mounted within the dirty air inlet 37 via the spindle 3. The brush bar 1 extends across the entire width of the dirty air inlet 37.

A cradle portion 39 is rotatably mounted within an inlet portion 38. It is sealingly mounted within inlet portion 38 to prevent the ingress of air. The cradle portion 39 comprises four rollers 43 positioned at each corner of the cradle 39 to aid gliding of the cleaner head over the surface to be cleaned. The rollers 43 are level with the brush bar to enable the brush bar to loosen dirt on a hand hook without it scraping the floor. The cradle portion 39 has two reinforcement bars 23 positioned at one-third intervals along the cradle and above the flattened areas 21 of the brush bar 1.

The cleaner head 31 further comprises a sole plate 45 which is fastened to the cleaner head by quick-release fasteners, for example, quarter-turn fasteners 47.

Alternatively, the sole plate 45 could be snap-fitted to the cradle by means of snap- fitting clips (not shown) or fitted by any other suitable quick-release mechanism. The sole plate is integral with the inlet portion 38 and the cradle portion 39. The quick- release sole plate 45 allows easy access to the interior of the cleaner head to clear any blockage. The sole plate 45 or at least a part of it may be transparent so that any blockages are immediately visible.

In use, the main body 33 of the vacuum cleaner is tilted rearwardly towards the user so that the cleaner head is pushed away from the user. As the vacuum cleaner is moved forwards and backwards across the surface to be cleaned, the cradle portion 39 tilts with respect to the inlet portion 38 of the cleaner head 31 so that it remains in contact with the surface to be cleaned whether the surface comprises a deep pile carpet or a hard floor and irrespective of the angle of tilt of the main body of the cleaner head.

Therefore, the dirty air inlet 37 remains in contact with the surface to be cleaned during use, maintaining good suction and hence improving the cleaning efficiency of the vacuum cleaner.

In the light of this disclosure, modifications of the described embodiments as well as other embodiments, all within the scope of the appended claims, will now become apparent to a person skilled in the art.