GB2569309A

GB2569309A - A cleaner head for a vaccum cleaner

Info

Publication number: GB2569309A
Application number: GB1720699.6A
Authority: GB
Inventors: Clifford Carter Thomas
Original assignee: Dyson Technology Ltd
Current assignee: Dyson Technology Ltd
Priority date: 2017-12-12
Filing date: 2017-12-12
Publication date: 2019-06-19
Anticipated expiration: 2037-12-12
Also published as: JP2021504052A; GB201720699D0; CN111491546A; US20210068601A1; GB2569309B; WO2019115988A1

Abstract

A cleaner head for a vacuum cleaner has a housing (12, fig. 1), an agitator (20) rotatably mounted within the housing, and first (56) and second (58) debris removal members. The first debris removal member is movable relative to the second debris removal member between a first position in which a debris collection channel (88) is defined, and a second position (fig. 16) in which the debris removal members are contiguous or overlapping, wherein movement from the first to the second position removes debris from the channel, movement of the first debris removal member is governed by rotation of the agitator. The mechanism may move the first member to the first position when the agitator moves at a speed above a pre-determined threshold and may move it to the second position when the agitator speed drops below a pre-determined threshold. The mechanism may comprise a weight (62, fig. 11) attached to the first member. The first member may be pivotally mounted to the second member. The first and second members may be removable from the cleaner had independently of the agitator. There may be a first and second further debris removal members defining a further channel (fig. 19).

Description

(57) A cleaner head for a vacuum cleaner has a housing (12, fig. 1), an agitator (20) rotatably mounted within the housing, and first (56) and second (58) debris removal members. The first debris removal member is movable relative to the second debris removal member between a first position in which a debris collection channel (88) is defined, and a second position (fig. 16) in which the debris removal members are contiguous or overlapping, wherein movement from the first to the second position removes debris from the channel, movement of the first debris removal member is governed by rotation of the agitator. The mechanism may move the first member to the first position when the agitator moves at a speed above a pre-determined threshold and may move it to the second position when the agitator speed drops below a pre-determined threshold. The mechanism may comprise a weight (62, fig. 11) attached to the first member. The first member may be pivotally mounted to the second member. The first and second members may be removable from the cleaner had independently of the agitator. There may be a first and second further debris removal members defining a further channel (fig. 19).

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A CLEANER HEAD FOR A VACUUM CLEANER

FIELD OF THE INVENTION

The present invention relates to a cleaner head for a vacuum cleaner.

BACKGROUND OF THE INVENTION

Cleaner heads for vacuum cleaners typically comprise an agitator for agitating debris located upon a surface, and a dirty air inlet through which agitated debris can pass.

During passage of agitated debris through the dirty air inlet, long strands of debris, for example hair or thread or the like, may become wrapped around the agitator or a mounting thereof. This may lead to an increased torque on the agitator, and a sufficient build-up of debris may lead to failure of the agitator, and hence a reduced pick-up performance.

It has previously been proposed to utilise a cutting blade mounted to a housing of a cleaner head, such that the cutting blade removes large strands of debris as the agitator rotates within the housing. This can lead to the generation of excessive friction and heat due to repeated engagement of the cutting blade with debris during rotation of the agitator.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided a cleaner head for a vacuum cleaner, the cleaner head comprising a housing, an agitator rotatably mounted within the housing, and first and second debris removal members, the first debris removal member being movable relative to the second debris removal member between a first position in which the first and second debris removal members are spaced apart to define a debris collection channel, and a second position in which the first and second debris removal members are contiguous or overlapping, wherein movement of the first debris removal member from the first position toward the second position removes debris from the debris collection channel, and movement of the first debris removal member is governed by rotation of the agitator.

The cleaner head according to the first aspect of the present invention may be advantageous principally as the first debris removal member is movable relative to the second debris removal member between a first position in which the first and second debris removal members are spaced apart to define a debris collection channel, and a second position in which the first and second debris removal members are contiguous or overlapping, movement of the first debris removal member from the first position toward the second position removes debris from the debris collection channel, and movement of the first debris removal member is governed by rotation of the agitator.

In particular, as the first debris removal member is movable relative to the second debris removal member between a first position in which the first and second debris removal members are spaced apart to define the debris collection channel, and a second position in which the first and second debris removal members are contiguous or overlapping, and movement of the first debris removal member from the first position toward the second position removes debris from the debris collection channel, the debris collection channel may only be defined when it is desired to collect debris therein, for example during operation of the cleaner head and/or agitator, and debris may be removed from the debris collection channel when the debris collection channel is no longer required to collect debris, for example when operation of the cleaner head and/or agitator has ceased.

Creation of the debris collection channel and removal of debris from the debris collection channel may thereby be selected to occur only once per operation of the cleaner head and agitator, which may reduce the amount of friction and/or heat generated by contact of the first and second debris removal members with debris in use.

Furthermore, as movement of the first debris removal member is governed by rotation of the agitator, this may remove the need for additional control, for example control by a user, to control movement of the first debris removal member, and movement of the first debris removal member may occur automatically during use of the cleaner head. This may ensure that debris is removed from the debris collection channel each time the cleaner head is used, thereby increasing maintenance intervals and reducing wear on the agitator.

As used herein the term “debris” is considered to refer to long strands of debris which have the potential to wrap around the agitator during operation of the cleaner head, unless otherwise stated. For example, debris may be considered to comprise debris having a length which is greater than the circumference of the agitator.

The first debris removal member may be configured to be in the first position when the agitator rotates at a speed above a pre-determined threshold, and to be in the second position when the agitator rotates at a speed below the predetermined threshold. This may be beneficial as this may ensure removal of debris occurs only once per operation of the cleaner head, for example when operation of the cleaner head has ceased, and hence the speed of rotation of the agitator has decreased or even stopped. This may reduce the amount of friction and/or heat generated by contact of the first and second debris removal members with debris in use. The first debris removal member may be configured to be in the first position during rotation of the agitator, and may be configured to be in the second position when the agitator is stationary. This may be beneficial as debris may be removed from the agitator every time the agitator is rotated.

The first debris removal member may comprise a first debris removal edge and the second debris removal member may comprise a second debris removal edge. The first and second debris removal members may be configured such that the first debris removal edge opposes the second debris removal edge when the first debris removal member is in the first position. This may be beneficial as movement of the first debris removal member from the first position to the second position may affect removal of debris from the debris collection channel by the first and/or second debris removal edge, for example by trapping and breaking or cutting or tearing the debris into smaller pieces which can no longer wrap around the agitator. Movement of the first debris removal member from the first position toward the second position may move the first debris removal edge toward the second debris removal edge.

Movement of the first debris removal member from the first position toward the second position, and vice versa, may comprise movement in a direction substantially parallel to a rotational axis of the agitator. This may be beneficial as it may ensure that debris falls into the debris collection channel when the first debris removal member is in the first position.

The first and/or second debris removal edge may comprise a cutting edge, and, for example, the first and/or second debris removal member may comprise a cutting blade. This may be beneficial as the first and second debris removal members may act to cut debris collected in the debris collection channel, thereby allowing removal of debris from the debris collection channel. In particular, cutting of debris may reduce the size, for example the length, of the debris, thereby ensuring that the debris does not have sufficient size to wrap around the agitator during use of the cleaner head. Cut debris may, for example, be collected by the cleaner head upon subsequent operation of the cleaner head.

The first and second debris removal members may together comprise a pair of scissors.

The first debris removal member may be biased toward the second position, and the cleaner head may, for example, comprise a biasing member for biasing the first debris removal member toward the second position. This may be beneficial as this may ensure that the first debris removal member moves from the first position to the second position with sufficient force to remove debris from the debris collection channel. Furthermore, this may ensure that the first debris removal member returns to the second position when the speed of rotation of the agitator drops below the pre-determined threshold, for example post-operation of the cleaner head, thereby ensuring that debris is removed from the debris channel each time the cleaner head is used. The biasing member may comprise a spring.

The biasing member may at least partially determine operating conditions for movement of the first debris removal member. For example, a force sufficient to overcome the biasing force applied by the biasing member may be required to move the first debris removal member from the second position toward the first position.

The first debris removal member may be pivotally mounted to the second debris removal member. This may be beneficial as it may enable a simpler and/or more compact arrangement than, for example, a sliding arrangement.

The cleaner head may comprise a movement mechanism for affecting movement of the first debris removal member between the first and second positions. The movement mechanism may affect movement of the first debris removal member from the second position toward the first position when the agitator rotates at a speed above a pre-determined threshold, and the movement mechanism may affect movement of the first debris removal member from the first position toward the second position when the agitator rotates at a speed below the pre-determined threshold. This may be beneficial as this may enable movement of the first debris removal member independently of a user, and may allow for automatic removal of debris from the debris collection channel without the need for user interference.

The movement mechanism may comprise a weight attached to the first debris removal member, for example via a connecting arm. Such a movement mechanism may be beneficial as it may provide a simple mechanical arrangement, which may be less expensive and more robust than, for example, an electronic control arrangement. Rotation of the agitator, for example at a speed above the pre-determined threshold, may move the weight from an equilibrium position to a displaced position, and this may move the first debris removal member from the second position to the first position.

When the speed of rotation of the agitator falls below the pre-determined threshold, the weight may be moved from the displaced position towards the equilibrium position, and this may move the first debris removal member from the first position toward the second position. The first debris removal member may be in the second position when the weight substantially reaches its equilibrium position, for example when the agitator is substantially stationary.

The biasing member may move the weight from the displaced position towards the equilibrium position, and this may move the first debris removal member from the first position toward the second position, when the speed of rotation of the agitator falls below the pre-determined threshold. This may be beneficial as the biasing member may ensure that the first debris removal member moves from the first position toward the second position with sufficient force to remove debris from the debris collection channel.

The equilibrium position may comprise a position adopted by the weight in the absence of any applied driving forces to the agitator. The weight may be disposed away from a central longitudinal axis of the agitator in the equilibrium position.

The first and second debris removal members may be mounted to the agitator at an end of the agitator, for example such that the debris collection channel is located at an end of the agitator. This may be beneficial as it may enable a simpler arrangement and/or may require less modification of a conventional agitator than, for example, an arrangement in which the first and second debris removal members are mounted between the end points of the agitator.

The agitator may be configured to migrate debris toward the debris collection channel during rotation of the agitator, for example toward an end of the agitator. This may be beneficial as it may ensure that debris is received within the debris collection channel, and hence ensure that debris is removed from the agitator by the first and second debris removal members once operation of the agitator has ceased. Where the debris collection channel is located at an end of the agitator, removal of debris from the debris collection channel may not involve contact of the first and second debris removal members with bristles of the agitator, which may lead to reduced wear and increased lifetime of the agitator. The debris collection channel being located at an end of the agitator may also be beneficial as this may prevent migration of debris toward and/or into bearing assemblies which mount the agitator to the housing. This may reduce the risk of failure of the cleaner head, and may increase the lifetime of the cleaner head.

The agitator may comprise at least one guiding formation for guiding debris toward the debris collection channel. The at least one guiding formation may comprise a projection upstanding from an outer surface of the agitator, and may, for example, comprise a helical or chevron-shaped projection.

The first and second debris removal members may be mounted to a common base, and, for example, at least a portion of the common base may be received within an end of the agitator. This may be beneficial as it may enable a simple mounting of the first and second debris removal members relative to the agitator. Furthermore, as at least a portion of the common base may be received within an end of the agitator, components which may be vulnerable to debris flowing through the cleaner head in use, such as the movement mechanism, for example, may be housed within the agitator, and hence protected from dirty air flow through the cleaner head. This may also allow for a compact arrangement, which may reduce the size of the housing and the overall footprint of the cleaner head. The movement mechanism may be located within the agitator, and the first and second debris removal members may be at least partially located outside the agitator. The first and second debris removal edges may be located outside the agitator when the first debris removal member is in the first position. The common base may comprise a plug, for example a plug for insertion into an open end of the agitator.

The first and second debris removal members may be removable from the cleaner head and/or the agitator. This may be beneficial as it may allow maintenance and/or replacement of the first and second debris removal members. Where the first debris removal member is in the second position when the agitator is stationary, the debris removal edges may not be exposed when the agitator is stationary, thereby allowing for safe removal of the first and second debris removal members by a user. The first and second debris removal members may be removable from the cleaner head independently of the agitator. This may be beneficial as it may enable maintenance and/or replacement of the first and second debris removal members without the need for a user to remove the agitator from the cleaner head, thereby enabling a simpler maintenance and/or replacement operation to be performed by a user.

The combination of the common base, the first and second debris removal members, and the movement mechanism, may be referred to as a debris removal module, and the debris removal module may be removable from the cleaner head and/or the agitator.

The debris removal module may be mounted to the agitator such that the debris removal module is rotatable with the agitator.

The cleaner head may comprise a first further debris removal member and a second further debris removal member, the first further debris removal member being movable relative to the second further debris removal member between a first position in which the first and second further debris removal members are spaced apart to define a further debris collection channel, and a second position in which the first and second further debris removal members are contiguous or overlapping. Thus the cleaner head may comprise first and second pairs of debris removal members, each pair defining a debris collection channel when a first debris removal member of each pair is in its respective first position. This may be beneficial as it may allow for an increase in the efficiency of debris removal from the agitator.

Movement of the further debris removal members may be governed by a further movement mechanism having substantially the same form as the movement mechanism previously described.

The further pair of debris removal members may be mounted to the common base, and may, for example, be located on the common base diametrically opposite to the first pair of debris removal members. This may be beneficial as debris collected within the debris collection channels may be contacted by the debris removal members at multiple points, which may allow for the debris to be broken down into smaller pieces, and may enable more efficient removal of debris.

According to a second aspect of the present invention there is provided a vacuum cleaner comprising a cleaner head according to the first aspect of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to better understand the present invention, and to show more clearly how the invention may be put into effect, the invention will now be described, by way of example, with reference to the following drawings:

Figure 1 is a top plan view of a first embodiment of a cleaner head according to the present invention;

Figure 2 is a perspective view of the cleaner head of Figure 1;

Figure 3 is a bottom plan view of the cleaner head of Figure 1;

Figure 4 is a bottom plan view of the cleaner head of Figure 1 with its brush bar removed;

Figure 5 is a side view of a debris removal module used in the cleaner head of Figure 1;

Figure 6 is a side view of a base of the debris removal module of Figure 5 in isolation;

Figure 7 is a first perspective view of the debris removal module of Figure 5;

Figure 8 is a second perspective view of the debris removal module of Figure 5;

Figure 9 is a side view of the debris removal module of Figure 5 with its debris removal members in a collecting configuration;

Figure 10 is a side view of the debris removal module of Figure 5 with its debris removal members in a removal configuration;

Figure 11 is a side view of the debris removal module of Figure 9 with its base removed;

Figure 12 is a side view of the debris removal module of Figure 10 with its base removed;

Figure 13 is an enlarged side view of an end of the brushbar of the cleaner head of Figure 1, with the debris removal member in its collecting configuration;

Figure 14 is an enlarged side view of an end of the brushbar of the cleaner head of Figure 1, with the debris removal member in its removal configuration;

Figure 15 is a rotated view of Figure 13 with the base of the debris removal module removed;

Figure 16 is a rotated view of Figure 14 with the base of the debris removal module removed;

Figure 17 is a bottom plan view of a second embodiment of a cleaner head according to the present invention;

Figure 18 is a side view of the debris removal module used in the cleaner head of Figure 17;

Figure 19 is a side view of the debris removal module of Figure 18 with its base removed; and

Figure 20 is a perspective view of a vacuum cleaner according to the present invention.

DETAILED DESCRIPTION

A first embodiment of a cleaner head according to the present invention, generally designated 10, is shown in Figures 1-4.

The cleaner head 10 comprises a housing 12, a dirty air inlet 14, a dirty air outlet 16, a connection formation 18 extending from the dirty air outlet 16, an agitator in the form of a brush bar 20, a motor and drive unit 22, and a debris removal module 23.

The housing 12 has an upper wall 24, opposing side walls 26, a sole plate 28, a front wall 30, and a rear wall 32. Together the walls 24,26,28,30,32 define a substantially hollow internal chamber 34. An aperture formed in the sole plate 28 defines the dirty air inlet 14, whilst an aperture formed in the rear wall 30 defines the dirty air outlet 16. The connection formation 18 is generally tubular in form, and extends from the dirty air outlet 16 to enable the cleaner head 10 to be connected to a vacuum cleaner main body, either directly, or, for example, via an appropriate wand. The connection formation 18 has a first pair of wheels 36, and the housing 12 has a second pair of wheels 37, which enable the cleaner head 10 to move across a surface to be cleaned in use.

One of the opposing side walls 26 comprises a removable end cap 38, which enables selective access to the substantially hollow internal chamber 34 of the cleaner head 10.

The brush bar 20 is substantially cylindrical in form, and has a substantially hollow interior 40, as seen in Figures 15 and 16. An outermost surface of the brush bar 20 has helical bristle strips (not shown) mounted thereto, and upstanding helical ridges 44 which extend along the brush bar 20 either side of the helical bristle strips, such that each helical bristle strip is located between a pair of upstanding helical ridges 44. The upstanding helical ridges 44 guide large debris along the brush bar 20 in use, toward a second end 48 of the brush bar 20.

The brush bar 20 is located within the substantially hollow internal chamber 34, and is rotatably mounted relative to the housing 12. The nature of the mounting of the brush bar 20 is conventional, and will not be described here in detail save to say that a first end 46 of the brush bar 20 is removably mounted to a first bearing assembly attached to one side wall 26 of the housing 12, whilst a second end 48 of the brush bar 20 is removably mounted to the debris removal module 23, which is in turn removably mounted to a second bearing assembly attached to the removable end cap 38. The brush bar 20 is mounted such that at least a portion of the helical bristle strips extend through the dirty air inlet 14, thereby enabling the helical bristle strips to contact a surface to be cleaned and agitate debris located thereon.

The motor and drive unit 22 is conventional, and is housed within the substantially hollow interior 40 of the brush bar 20, for example such that the brush bar 20 resembles a sleeve located about the motor and drive unit 22 within the substantially hollow internal chamber 34 of the housing 12.

The debris removal module 23 is shown in more detail in Figures 5-12, and comprises a base 54, first 56 and second 58 debris removal members, a connecting arm 60, a counterweight 62, and a spring 64.

The base 54 is shown in isolation in Figure 6, and has a frusto-conical end portion 66, a cylindrical intermediate portion 68, and a pair of opposing arms 70. The frusto-conical end portion 66 has a spindle 72 extending therefrom, which is received in the second bearing assembly of the removable end cap 38 to allow rotation of the base 54 relative to the housing 12. The frusto-conical end portion 66 has a largest diameter greater than the internal diameter of the brush bar 20, thereby preventing over-insertion of the base 54 into the second end 48 of the brush bar 20. The flattened peak of the frusto-conical end portion 66 is connected to a first flat face of the cylindrical intermediate portion 68, such that a gap 74 is formed between the frusto-conical end portion 66 and the cylindrical intermediate portion 68.

The cylindrical intermediate portion 68 has a channel 76 for receiving the first 56 and second 58 debris removal members. The pair of opposing arms 70 extend orthogonally from a second flat face of the cylindrical intermediate portion 68, and define a hollow region 78 of the base 54. The pair of opposing arms 70 extend in a direction substantially parallel to an axis of rotation of the brush bar 20, thereby defining a contact region between the innermost radial surface of the brush bar 20 and the base 54.

The cylindrical intermediate portion 68 has a diameter substantially corresponding to the internal diameter of the brush bar 20, and the pair of opposing arms 70 define a width substantially corresponding to the internal diameter of the brush bar 20, such that the base 54 is received snugly within the substantially hollow interior 40 of the brush bar 20 via a push-fit.

The second debris removal member 58 is fixedly mounted to the base 54, whilst the first debris removal member 56 is pivotally mounted relative to both the base 54 and the second debris removal member 58.

The first 56 and second 58 debris removal members each have a corresponding blade portion 80,82, and a corresponding support portion 84,86. Each blade portion 80,82 has a cutting edge 81. As can be seen, for example from Figures 11 and 12, together the first 56 and second 58 debris removal members resemble a pair of scissors.

The connecting arm 60 is mounted at one end to the support portion 84 of the first debris removal member 56, and at another end to the counterweight 62. The counterweight 62 is a simple weight, the weight of which is chosen depending on the desired operational characteristics of the debris removal module 23, as will be discussed hereafter. The spring 64 extends from one of the pair of opposing arms 70 of the base 54 to the connecting arm 60, across the hollow region 78 of the base 54. The connecting arm 60, counterweight 62, and spring 64 are housed within the brush bar 20, and the cylindrical intermediate portion 68 acts as a plug to close the end of the brush bar 20.

The first debris removal member 56 is movable between a closed configuration, shown in Figures 10, 12, 14, and 16, and an open configuration, shown in Figures 9, 11, 13, and 15.

In the closed configuration, the first 56 and second 58 debris removal members overlap one another, such that there is no gap between the first 56 and second 58 debris removal members, and the cutting edges 81 are not exposed. The first 56 debris removal member is held in this position by the connecting arm 60 and the counterweight 62, and is further biased toward this position by the action of the spring 64. The counterweight 62 is slightly offset from a rotational axis of the brush bar 20 in the closed configuration, and this position of the counterweight 62 is referred to as an equilibrium position. The first debris removal member 56 is in the closed configuration when the brush bar 20 rotates at a speed below a pre-determined threshold. For example, the first debris removal member 56 is in the closed configuration when the brush bar 20 is stationary, ie when no driving forces are applied to the brush bar 20 by the motor and drive unit 22.

In the open configuration, the first debris removal member 56 extends across the gap 74 between the frusto-conical end portion 66 and the cylindrical intermediate portion 68 of the base 54, such that the first 56 and second 58 debris removal members define a debris collection channel 88. The cutting edges 81 of the first 56 and second 58 debris removal members are exposed, and define the opposing edges of the debris collection channel 88. The counterweight 62 is displaced from its equilibrium position in a radially outward direction of the brush bar 20, against the action of the spring 64. The base 54 is located within the brush bar 20 such that the cutting edge 81 of the second debris removal member 58 is substantially coincident with the second end 48 of the brush bar 20, and thus an edge of the debris collection channel 88 is substantially coincident with the second end 48 of the brush bar 20. The first debris removal member 56 is in the open configuration when the brush bar 20 rotates at a speed above a pre-determined threshold.

During operation, the cleaner head 10 is attached to a vacuum cleaner 100.

Prior to a driving force being applied to the brush bar 20 by the motor and drive unit 22, the first debris removal member 56 is in its closed configuration, as shown in Figures 10, 12, 14, and 16.

When a driving force is applied to the brush bar 20 by the motor and drive unit 22, the brush bar 20 rotates within the housing 12, and the debris removal module 23 rotates along with the brush bar 20. When the speed of rotation of the brush bar 20 is above a pre-determined threshold, forces experienced by the counterweight 62 throw the counterweight 62 radially outwardly from its equilibrium position, against the action of the spring 64, toward a displaced position near the radially innermost surface of the brush bar 20. Movement of the counterweight 62 causes pivotal movement of the first debris removal member 56 by virtue of the connecting arm 60. The first debris removal member 56 extends across the gap 74, such that the debris collection channel 88 is defined by the cutting edges 81 of the first 56 and second 58 debris removal members.

During movement of the vacuum cleaner 100, and hence the cleaner head 10, across a surface to be cleaned, the helical bristle strips contact the surface to agitate debris located on the surface. Debris is entrained in air flow through the cleaner head 10, and enters the cleaner head 10 through the dirty air inlet 14. Long strands of debris which have the potential to wrap around the brush bar 20 contact the upstanding helical ridges 44 of the brush bar 20, and are guided into the debris collection channel 88 formed at the second end 48 of the brush bar 20 by interaction with the surface and the upstanding helical ridges 44.

When the speed of rotation of the brush bar 20 falls below the pre-determined threshold, for example when a driving force is no longer applied to the brush bar 20, the forces experienced during rotation are no longer sufficient to retain the counterweight 62 in its displaced position, and the counterweight 62 moves from its displaced position radially inwardly toward the centre of the brush bar 20, ie towards its equilibrium position. As the counterweight 62 moves toward its equilibrium position, the first debris removal member 56 moves toward the second debris removal member 58, thereby reducing the size of the debris collection channel 88, and thereby causing the cutting edges 81 of the respective debris removal members 54,56 to contact the debris contained within the debris collection channel 88. This causes the debris to be cut into smaller, more manageable, pieces, which are no longer capable of wrapping around the brush bar, and can be entrained in air flow through the cleaner head 10, for example upon next operation of the vacuum cleaner 100.

In certain embodiments the spring 64 acts to move the first debris removal member 56 to its closed configuration as soon as the speed of rotation of the brush bar 20 drops below the pre-determined threshold. Alternatively, the counterweight 62 continues to move towards its equilibrium position as rotation of the brush bar 20 ramps down, thereby moving the first debris removal member 56 ever closer to the second debris removal member 58, until rotation of the brush bar 20 ceases, and the first debris removal member 56 is again in its closed configuration as shown in Figures 10, 12, 14, and 16. The biasing action of the spring 64 also helps to draw the counterweight 62 toward its equilibrium position, and hence to draw the first debris removal member 56 to its closed configuration.

As the removal of debris from the debris collection channel 88 only occurs once there are no longer any applied driving forces to the brush bar 20, ie once operation of the vacuum cleaner 100 has ceased, removal of debris only occurs once per operation of the vacuum cleaner 100, and hence generation of excessive friction and heat may be avoided.

Furthermore, it can be seen that the weight of the counterweight 62, and the resilience of the spring 64, have an impact on operation of the debris removal module 23. Thus by choosing the weight of the counterweight 62 and the resilience of the spring 64, the operating characteristics of the cleaner head 10 can be chosen. For example, a heavier spring may result in a larger cutting force being applied by the first 56 and second 58 debris removal members, but may also require higher rotational speeds of the brush bar 20 to initially separate the first 56 and second 58 debris removal members. In contrast, a lighter spring may result in a lower cutting force being applied by the first 56 and second 58 debris removal members, but may also require lower rotational speeds of the brush bar 20 to initially separate the first 56 and second 58 debris removal members.

If it is desired to remove the debris removal module 23, for example for cleaning or replacement, then the removable end cap 38 of the housing 12 closest to the debris removal module 23 can be removed by a user. A user can then withdraw the debris removal module 23 from within the housing 12, either with the brush bar 20, or independently of the brush bar 20. In particular, as the base 54 of the debris removal module 23 is received within the second end 48 of the brush bar 20 with a push-fit, application of sufficient force to the debris removal module 23 may remove the base 54 from the interior of the brush bar 20, thereby allowing for cleaning or replacement of the debris removal module 23 as desired. The frusto-conical end portion 66 may provide a convenient grip for a user to pull the base 54 from within the brush bar 20.

A second embodiment of a cleaner head according to the first aspect of the present invention, generally designated 200, is shown in Figure 17.

The second embodiment of the cleaner head 200 is substantially the same as the first embodiment of the cleaner head 10, and differs only in that the debris removal module 23 comprises an additional pair of debris removal members 202, 204, an additional connecting arm 206, an additional counterweight 208, and an additional spring (not shown), as seen in Figures 18 and 19. The additional components are structurally and functionally identical to the corresponding components of the first embodiment of the cleaner head 10, and differ only in that they are mounted on opposite sides of the cylindrical intermediate portion 68 and the pair of opposing arms 70 of the base 54.

Thus in the second embodiment there are two pairs of debris removal members 56,58,202,204 which are diametrically opposed upon the base 54, defining first 86 and second 210 debris collection channels. This may enable the cutting of debris into smaller pieces, thereby enhancing the efficiency of removal of debris from the brush bar 20.

Claims

1. A cleaner head for a vacuum cleaner, the cleaner head comprising a housing, an agitator rotatably mounted within the housing, and first and second debris removal members, the first debris removal member being movable relative to the second debris removal member between a first position in which the first and second debris removal members are spaced apart to define a debris collection channel, and a second position in which the first and second debris removal members are contiguous or overlapping, wherein movement of the first debris removal member from the first position toward the second position removes debris from the debris collection channel, and movement of the first debris removal member is governed by rotation of the agitator.

2. A cleaner head as claimed in Claim 1, wherein the first debris removal member is configured to be in the first position when the agitator rotates at a speed above a pre-determined threshold, and to be in the second position when the agitator rotates at a speed below the pre-determined threshold.

3. A cleaner head as claimed in Claim 2, wherein the cleaner head comprises a movement mechanism for affecting movement of the first debris removal member between the first and second positions, the movement mechanism affects movement of the first debris removal member from the second position toward the first position when the agitator rotates at a speed above the pre-determined threshold, and the movement mechanism affects movement of the first debris removal member from the first position toward the second position when the agitator rotates at a speed below the pre-determined threshold.

4. A cleaner head as claimed in Claim 3, wherein the movement mechanism comprises a weight attached to the first debris removal member.

5. A cleaner head as claimed in any preceding claim, wherein the first debris removal member comprises a first debris removal edge, the second debris removal member comprises a second debris removal edge, and the first and second debris removal members are configured such that the first debris removal edge opposes the second debris removal edge when the first debris removal member is in the first position.

6. A cleaner head as claimed in Claim 5, wherein the first and/or second debris removal edge comprises a cutting edge.

7. A cleaner head as claimed in any preceding claim, wherein the first debris removal member is biased toward the second position.

8. A cleaner head as claimed in any preceding claim, wherein the first debris removal member is pivotally mounted to the second debris removal member.

9. A cleaner head as claimed in any preceding claim, wherein the first and second debris removal members are mounted to the agitator at an end of the agitator such that the debris collection channel is located at the end of the agitator.

10. A cleaner head as claimed in any preceding claim, wherein the agitator is configured to migrate debris toward the debris collection channel during rotation of the agitator.

11. A cleaner head as claimed in any preceding claim, wherein the first and second debris removal members are mounted to a common base, and at least a portion of the common base is received within an end of the agitator.

12. A cleaner head as claimed in any preceding claim, wherein the first and second debris removal members are removable from the cleaner head and/or the agitator.

5

13. A cleaner head as claimed in any preceding claim, wherein the first and second debris removal members are removable from the cleaner head independently of the agitator.

14. A cleaner head as claimed in any preceding claim, wherein the cleaner

10 head comprises a first further debris removal member and a second further debris removal member, the first further debris removal member being movable relative to the second further debris removal member between a first position in which the first and second further debris removal members are spaced apart to define a further debris collection channel, and a second position in which the

15. A vacuum cleaner comprising a cleaner head as claimed in any preceding claim.

15 first and second further debris removal members are contiguous or overlapping.