Vacuum cleaner head bleed system

Abstract

A vacuum cleaner head comprises a housing having a suction chamber and an agitator element 27 mounted for rotation. The housing comprises bleeds (32, 33, fig 3) having a bleed closure (36, fig 4) and

Description

B ACKGROUND It is known to provide a vacuum cleaner comprising a cleaner head which has one or more selectively openable bleeds for admitting larger pieces of debris into the suction chamber. Typically it is desirable to open the bleeds when operating the cleaner head on a hard surface where larger debris otherwise tends to collect at the front of the cleaner head, large debris being unable to pass under the cleaner head via the relatively small gap between the bottom of the cleaner head and the floor. However, it is less desirable to open the bleeds on a carpeted surface due to the loss of suction head which results from opening the bleeds as generally a high suction head is required to sufficiently clean a carpeted surface. SUMMARY The present invention provides a cleaner head for a vacuum cleaner, the cleaner head comprising: a housing defining a suction chamber, wherein the housing comprises a suction chamber bleed having a bleed closure and a bleed closure actuator, an agitator element mounted for rotation about an axis; and a bleed actuator system comprising a first member moveably mounted with respect to the housing and configured to selectively operate the bleed closure actuator, and a second member attached to the agitator element and constrained for rotation therewith, wherein either: the first member comprises a magnetic field generator and the second member comprises a metal member; or the first member comprises a metal member and the second member comprises a magnetic field generator, wherein the bleed actuator system is configured so that, in use, when the agitator element rotates, relative movement between the first member and the second member causes the first member to move relative to the housing to operate the bleed closure actuator. The present invention is advantageous as the rotation of the agitator element may be used to cause automatic opening of the suction chamber bleeds. This is beneficial when cleaning hard floors which do not require high agitator element rotational speeds such that the suction chamber bleeds can open automatically when the vacuum cleaner is being used to clean a hard floor. Optionally the second member is moveably attached to the agitator element and configured so that when the agitator element rotates at a speed at or above a predetermined threshold, the second member moves with respect to the agitator element to a position in which the relative movement between the first member and the second member no longer causes the first member to move relative to the housing. This is beneficial when cleaning carpeted floors which require a high agitator element rotational speed such that the suction chamber bleeds close automatically when the vacuum cleaner is being used to clean a carpeted floor. The second member is optionally radially biased towards the axis of rotation of the agitator element to maintain the second member in the vicinity of the first member at lower rotational speeds. The first member may be biased towards a rest position and / or the bleed closure actuator may be biased towards a closed position such that the bleed closure actuator is caused to close when the agitator element is stationary, or when relative movement between the first member and the second member no longer causes the first member to move relative to the motor shaft or the housing. Optionally the magnetic field generator comprises a permanent magnet or an electromagnet. The metal member optionally comprises a disc or ring. The first member may comprise an actuator arm to facilitate actuation of the bleed closure actuator. In one example, the first member is in operative engagement with a wire and pulley mechanism to effect operation of the bleed closure actuator. For example, the pulley may be in operative engagement with the first member, and wherein the wire is in operative engagement with the bleed closure actuator, wherein, in use, movement of the first member relative to the housing causes the wire to wind around the pulley to pull the bleed closure actuator towards the pulley and open the bleed closure. In one example, the first member is in operative engagement with a rack and pinion mechanism to effect operation of the bleed closure actuator. For example, the rack may be in operative engagement with the bleed closure actuator and wherein the pinion is in operative engagement with the first member, wherein, in use, movement of the first member relative to the housing causes the pinion to rotate and act on the rack to open the bleed closure. Optionally the first member comprises gear teeth which operatively engage the pinion. In another aspect, the present invention provides a vacuum cleaner comprising a cleaner head as described above. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a schematic isometric view of a vacuum cleaner; Figure 2 shows a schematic isometric view of a cleaner head of the vacuum cleaner; Figure 3 shows an alternative schematic isometric view of the cleaner head; Figure 4 shows a schematic partial isometric view of the interior of the cleaner head; and Figure 5 shows a schematic isometric view of a bleed actuator system. DETAILED DESCRIPTION Figure 1 shows a hand-held vacuum cleaner 10 comprising a main body 12, a wand 14 and a cleaner head 20. The main body 12 comprises a separating system, in the form of a cyclonic separator, a motor and impeller (not visible) arranged to draw air through the separating system, and a power supply 13, in the form of a battery, for powering the motor. The wand 14 is attached at one end to the main body 12 via an adaptor 17, and at the other end to the cleaner head 20 via an adaptor 15. The wand 14 provides fluid communication between the cleaner head 20 and the separating system and supports the cleaner head 20 during use. Referring to Figure 2, the cleaner head 20 comprises an adaptor 21 which is releasably attached to the adaptor 15 of the wand 14. A spring loaded button 22 operates to secure the cleaner head 20 to the wand 14. If it is desired to remove the cleaner head 20 from the wand 14 (for example to replace the cleaner head 20 with an alternative cleaner head), the button 22 is depressed to allow the cleaner head 20 to be released from the wand 14. The cleaner head 20 comprises a housing 23 which defines a suction chamber (not shown) and an outlet 24 which provides fluidic communication between the suction chamber and the separating system via the adaptor 21 and the wand 14. An agitator element 27, such as a brush bar, is rotatably mounted about an axis of rotation on a motor shaft 52 (Figure 5) within the suction chamber between end supports 25, 26 (see Figure 4). The housing 23 comprises a cover 29 and a sole plate 30. As best seen in Figure 4, the sole plate 30 comprises an opening 31 which defines the main inlet to the suction chamber. The agitator element 27 is configured and mounted with respect to the opening 31 so that, in use, at least part of the agitator element 27 contacts the floor to be cleaned via the opening 31 to agitate dust and debris on the floor. The cleaner head 20 may also be operated with a stationary agitator element 27 such that suction head alone causes dust and debris to be drawn into the suction chamber. The sole plate 30 comprises two suction chamber bleeds 32, 33 each of which comprises a bleed opening 34, 35 and a selectively openable bleed closure 36, 37. When the bleed closures 36, 37 are in the open position (see Figure 3), the bleed openings 34, 35 provide access to the suction chamber through which larger items of debris, which will not fit between the bottom of the sole plate 30 and the ground, may pass. A bleed closure actuator 38 is operatively attached to the bleed closures 36, 37. The bleed closure actuator 38 is configured to open and / or close the bleed closures 36, 37. In an alternative example, each bleed closure 36, 37 may be provided with its own bleed closure actuator. Two suction chamber bleeds 32, 33 are shown in the example of Figure 4. However, it will be understood that only one suction chamber bleed, or more than two suction chamber bleeds, may be provided. Alternatively or additionally, one or more suction chamber bleeds may be provided in the housing 23 on the opposite side of the opening 31 to the suction chamber bleeds 32, 33 illustrated in Figure 4. Referring to Figures 2 and 3, the bleeds 36 are shown in their closed configuration in Figure 2 and in their open configuration in Figure 3. Figure 5 shows a schematic view of an example bleed actuator system 50. The bleed actuator system 50 comprises a first member 51 which is moveably attached to a motor mount 52. The first member 51 is configured to selectively operate the bleed closure actuator 38 as will be described in greater detail below. Two second members 53 are attached to the agitator element 27 and constrained for rotation therewith. In this example the two second members 53 comprise magnetic field generators in the form of permanent magnets. Each second member 53 is located in a recess 54 formed within the agitator element 27. The slots 52 each comprise a stop 55 located at a radially inward location against which the second members 53 are biased by resilient members 56 which in this example comprise springs. The second members 53 are therefore radially biased towards the axis of rotation of the agitator element 27. In an alternative example, the second members 53 may be installed within a carrier which is configured to be attached to the end of the brush bar 27 and to rotate with the brush bar 27 in use. In this example, the first member 51 comprises a steel ring which is fixedly attached to an actuator member 57 which comprises an actuator arm 58. In another example, the first member 51 may be integrally formed with the actuator member 57. The actuator arm 58 comprises gear teeth 59 which operatively engage the teeth of a pinion gear 60 which is in operative engagement with the teeth of an associated rack 61 which is attached to the bleed closure actuator 38. The bleed closure actuator 38 is biased towards the closed position by a resilient member 62, such as a spring. An end stop 63 is provided to limit the movement of the bleed closure actuator 38. In use, when the agitator element 27 rotates at a speed below a predetermined threshold (for example 2000 RPM), the relative movement between the first member 51 and the second members 53 causes the first member 51 to move relative to the motor mount 52 due to Lenz’s law. As shown in Figure 5, anti-clockwise rotation (arrow A) of the agitator element 27 results in an anti-clockwise rotation (arrow B) of the first member 51. The gear teeth 59 located on the actuator arm 58 engage with the teeth of the pinion gear 60 causing clockwise (arrow C) rotation of the pinion gear 60 and upward movement (arrow D) of the rack 61 to cause opening of the bleed closure member 38 against the action of the resilient member 62. The relative movement between the first member 51 and the second members 53 therefore causes operation of the bleed closure actuator 38 to open the bleed closures 36, 37. When the agitator element 27 rotates at a speed at or above the predetermined threshold (for example 3000 RPM), centrifugal forces acting on the second members 53 cause the second members 53 to move radially outwardly with respect to the axis of rotation of the agitator element 27 against the bias of resilient members 56. Consequently, the relative movement between the first member 51 and the second members 53 no longer induces Lenz’s law and no longer causes the first member 51 to move relative to the motor mount 52. As a result, no opening force is applied to the bleed closure actuator 38 via the actuator arm 58 and the rack and pinion mechanism 61, 60. The bleed closure actuator 38 therefore closes under the action of the resilient member 62 causing the bleed closures 36, 37 to close. If desired, an override mechanism, or a separate actuator mechanism, may be provided to open the bleeds 32, 33 when the agitator element 27 is rotating at a speed at or above the predetermined threshold. For example, a user may elect to manually operate the bleeds 32, 33 to enable large items to pass into the suction chamber regardless of the speed of rotation of the agitator element 27. In an alternative example, the first member 51 may be biased towards a rest position such that when relative movement between the first member 51 and the second members 53 no longer causes the first member 51 to move relative to the motor mount 52, or when there is no relative movement between the first 51 and second 53 members, the first member 51 returns to its rest position causing the bleed closure actuator 38 to move to the closed position via the rack and pinion mechanism 61, 60. The biasing of the first member 51 to a rest position may be provided in addition to, or as an alternative to the biasing of the bleed closure actuator 38 to the closed position. It is not essential that the first member 51 comprises steel and the first member 51 may instead comprise any suitable magnetically conductive metal member. The first member 51 may be in the form of a ring or a disc, or a plurality of first members 51 attached to the actuator member 57 may be used as an alternative to a continuous first member 51. It will be understood that the arrangement described above in respect of Figure 5 may be reversed such that the first member 51 comprises a magnetic field generator and the second members 53 comprise any suitable metal member. It is not essential that two second members 53 be used and only one, or more than two second members 53 may be used instead. The magnetic field generator, whether the first 51 or second 53 member may comprise a permanent magnet or electromagnet. In an alternative example, the first member(s) 51 may be moveably attached to the motor shaft rather than to the motor mount 52. In a further alternative example, the first member(s) 51 may be moveably attached to the housing. For example the first member(s) may be mounted on the housing 20 within the suction chamber proximate one end of the agitator element 27 as illustrated in Figure 4. In this example, the second element(s) 53 are located at the end of the agitator element 27 proximate the first element(s) 51. Figure 4 shows part of an alternative bleed actuator system. In this example the first member comprises a metal ring 71 located within a carrier 72 which is moveably mounted to the inner wall of the housing 20 - specifically, to the inner wall of the end support 25 of the sole plate 30. A wire 73 is fixed at one end to the carrier 72 and fixed at its ither end to 5 the bleed closure actuator 38. The wire 73 and carrier 72 comprises a wire and pulley mechanism 70. In use, when the agitator element 27 rotates at a speed below the predetermined threshold, the relative movement between the first member 71 and the second members (located at 10 the end of the agitator element 27) causes the first member 71 to move relative to the housing 20 causing the wire 73 to wind around the carrier 72 and pull the bleed closure actuator 38 in a direction towards the carrier 72. This in turn causes the bleed closure actuator 38 to open the bleed closures 36, 37 as cam slots 74 move along pins 75. The bleed closure actuator 38 is biased to the closed position by spring 76. 15

Claims

1. A cleaner head for a vacuum cleaner, the cleaner head comprising:a housing defining a suction chamber, wherein the housing comprises a suction chamber bleed having a bleed closure and a bleed closure actuator,an agitator element mounted for rotation about an axis; anda bleed actuator system comprising a first member moveably mounted with respect to the housing and configured to selectively operate the bleed closure actuator, and a second member attached to the agitator element and constrained for rotation therewith, wherein either:the first member comprises a magnetic field generator and the second member comprises a metal member; orthe first member comprises a metal member and the second member comprises a magnetic field generator,wherein the bleed actuator system is configured so that, in use, when the agitator element rotates, relative movement between the first member and the second member causes the first member to move relative to the housing to operate the bleed closure actuator.

2. A cleaner head according to claim 1, wherein the second member is moveably attached to the agitator element and configured so that when the agitator element rotates at a speed at or above a predetermined threshold, the second member moves with respect to the agitator element to a position in which the relative movement between the first member and the second member no longer causes the first member to move relative to the housing.

3. A cleaner head according to claim 1 or 2, wherein the second member is radially biased towards the axis of rotation of the agitator element.

4. A cleaner head according to any preceding claim, wherein the first member is biased towards a rest position.

5. A cleaner head according to any preceding claim, wherein the bleed closure actuator is biased towards a closed position.

6. A cleaner head according to any preceding claim, wherein the magnetic field generator comprises a permanent magnet or an electromagnet.

7. A cleaner head according to any preceding claim, wherein the metal member comprises a disc or ring.

8. A cleaner head according to any preceding claim, wherein the first member comprises an actuator arm.

9. A cleaner head according to any preceding claim, wherein the first member is in operative engagement with a wire and pulley mechanism, wherein the pulley is in operative engagement with the first member, and wherein the wire is in operative engagement with the bleed closure actuator, wherein, in use, movement of the first member relative to the housing causes the wire to wind around the pulley to pull the bleed closure actuator towards the pulley open the bleed closure.

10. A cleaner head according to any preceding claim, wherein the first member is in operative engagement with a rack and pinion mechanism, wherein the rack is in operative engagement with the bleed closure actuator and wherein the pinion is in operative engagement with the first member, wherein in use, movement of the first member relative to the housing causes the pinion to rotate and act on the rack to open the bleed closure.

11. A cleaner head according to claim 10, wherein the first member comprises gear teeth which operatively engage the pinion.

12. A vacuum cleaner comprising a cleaner head according to any preceding claim.

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