WO2017194910A1

WO2017194910A1 - Cleaner head

Info

Publication number: WO2017194910A1
Application number: PCT/GB2017/051186
Authority: WO
Inventors: Lucas Horne; Pablo MONTERO-COWELL; Oliver SKITTERY
Original assignee: Lupe Technology Limited
Priority date: 2016-05-11
Filing date: 2017-04-27
Publication date: 2017-11-16
Also published as: GB2550179A; GB201608292D0; GB2550179B

Abstract

A cleaner head (10) for a recirculating vacuum cleaner has a suction inlet (20) defined in the lower face of a housing (11) and a suction passageway (20A) through the housing (11). The cleaner head (10) has a recirculated fluid outlet (30) configured to direct at least a portion of recirculated fluid towards the floor surface. A rotatable sealing element (40) is located at a front of the housing (11). The rotatable sealing element (40) has a rotational axis (41 ) which is parallel to the lower face of the cleaner head. The suction inlet (20) and the suction passageway (20A) are located between the recirculated fluid outlet (30) and the rotatable sealing element (40). The cleaner head (10) may include a shielding member (50) located between the recirculated fluid outlet (30) and the rotatable sealing element (40).

Description

CLEANER HEAD

Background

Vacuum cleaners are a well-known form of appliance. Most vacuum cleaners today operate in a fundamentally similar way. The vacuum cleaner comprises a cleaner head (pick- up head) which is pushed across a surface, a separation system which can separate dirt/dust from an airflow, and a suction source (typically a motor and an impeller) to generate an airflow through the cleaner head and separation system. Dust/dirt is drawn from the surface to be cleaned and entrained in an airflow. The dirty airflow is pulled from the cleaner head to the separation system. Cleaned air is exhausted to the room. As the air is exhausted a negative pressure is created at the pickup head.

There are many variations of: cleaner head (for example, cleaner heads with and without beater bars); separation systems (filter bags, cyclonic separators, water tank) and sizes and designs of motor. However, there is typically a common feature that all entrained air is ultimately exhausted back to the room. This will be called an Open loop' system.

A known alternative approach will be called a recirculating system, or a 'closed loop' system. In a recirculating air system, a portion (or theoretically all) of the airflow is continuously circulated. Dust/dirt is entrained into an airflow at a cleaner head, the dirty airflow is drawn to a separation system where the dust/dirt is separated. However, instead of exhausting the cleaned air to the room, the cleaned air is returned to the system, generally to the cleaning surface, where it is re-drawn into the cleaner head. Therefore, the mechanism for entraining dirt is not purely reliant on suction and resulting negative pressure created, but is a combination of the returned exhaust flow 'positive' pressure and negative pressure. US 1 ,61 1 ,786 is an early example of a suction cleaner with recirculation of airflow.

A closed-loop system presents a number of theoretical benefits, including :

· Increased energy efficiency (as a result of directing the air back to the target spot to be cleaned, a lower wattage motor can be used to achieve the equivalent dust pick up over a conventional open system);

• Increased dust pick-up (as a result of higher air velocity generated at the cleaner head);

• Lower dust emissions in use (with theoretical zero emissions to atmosphere and less disturbance of dust on surfaces within the room due to no exhaust);

• Eliminated odour due to the containment of contaminated air;

• Lower noise (the sound of rushing air is contained);

• Lower push force (in a closed system the pressure at the head is balanced therefore with less negative pressure the cleaner head will not suck to the floor).

However, the closed-loop approach presents a number of problems which are yet to be adequately addressed by the prior art. One problem is returning the exhaust flow to the cleaner head without leaking and losing performance, especially over uneven floor surfaces. When the air from the motor is directed back to the cleaner head, the resulting positive pressure can be difficult to contain within the machine, resulting in debris being scattered away from the head.

US 7,458,130 uses protrusions on the underside of the pickup head that push into the carpet to be cleaned to try and form a seal with the surface and prevent the positive-pressure returned air from escaping to atmosphere. The scheme also utilises an expansion chamber in the return duct to slow the positive pressure air down, to again try and prevent it from escaping. However, by relying on solid protrusions to make a seal with the carpet makes it impossible to pick up large debris such as cereal without leaking air. In order to allow large debris such as cereal into the head it would be required to lift the pick-up head from the surface creating an undesired leak that could scatter dust away from the pick-up head. In US 7,458,130, the pick-up head needs to remain firmly on the surface to be cleaned in order to contain the recirculating flow, which is very limiting when trying to bring a variety of shapes and sizes of debris into the pick-up head. Likewise US 7,458,130 is limited to carpet and porous surfaces only and would not be suitable for hard wooden, stone or tiled floors as there is no means to create a seal with solid protrusions on a solid non porous floor surface.

US 6,237,188 uses a seal roller to maintain a seal to the surface and to bring in larger debris to the head. Returned air is applied at the front of the pickup head, parallel to the surface to be cleaned, in front of a beater bar rotating rearwards and behind the seal roller. This enables the pick-up head to remain on the surface to be cleaned whilst bringing in debris to the head. But due to the position of the return air duct, in between the seal roller and beater bar, there must be a free path for debris to pass from the seal roller to the beater bar, therefore the return air duct cannot terminate on or close to the surface to be cleaned if large debris is to be brought in to the pick-up head.

Embodiments of the present invention seek to improve the performance of a recirculating vacuum cleaner.

Summary

This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

An aspect provides a cleaner head for a recirculating vacuum cleaner comprising : a housing configured to be movable across a floor surface, the housing having a lower face; a suction inlet defined in the lower face of the housing;

a suction passageway through the housing, the suction passageway in fluid communication with the suction inlet;

a recirculated fluid outlet configured to direct at least a portion of recirculated fluid outwardly from the lower face towards the floor surface;

a rotatable sealing element located at a front of the housing, the rotatable sealing element having a rotational axis which is parallel to the lower face of the cleaner head, the housing at least partially surrounding the rotatable sealing element;

wherein the suction inlet and the suction passageway are located between the recirculated fluid outlet and the rotatable sealing element.

At least one example of the present disclosure has an advantage of providing good pick up performance on large debris, while also allowing a good degree of sealing to a range of floor surfaces. The rotatable sealing element allows debris to enter the cleaner head while a good degree of sealing is maintained, preventing the escape of recirculated fluid.

At least one example of the present disclosure has an advantage of providing good pick up performance as all, or at least part of, the recirculated air is exhausted towards the surface to be cleaned. The exhausted air can provide agitation of a flat non porous surface and when the cleaner head is on carpet pile ensures that recirculated air passes through the carpet pile and not over its surface. It has been found that in order to maximise the benefit of the recirculated exhaust flow, it is advantageous for the exhaust duct to terminate flush with the carpet pile in order to pass the exhaust air through the carpet pile, to agitate and free dirt, rather than passing the air over the surface of the carpet pile which has minimal effect in loosening debris within the carpet pile. Slowing down the recirculated flow is undesirable on hard non porous surfaces, and can be avoided in at least one example of this disclosure.

At least one example of the present disclosure provides a recirculating vacuum cleaner which improves containment of recirculated fluid (e.g. air) within the cleaner head.

The cleaner head may comprise a shielding member located between the recirculated fluid outlet and the rotatable sealing element. The suction passageway is in fluid communication with a portion of the rotatable sealing element above the shielding member.

The shielding member can have an advantage of reducing leakage of recirculated fluid from the cleaner head. The shielding member can have an advantage of reducing disturbance of debris brought into the cleaner head. The shielding member can have an advantage of improving sealing of the suction inlet and/or suction passageway when large debris is brought into the cleaner head by the rotatable sealing element. The shielding member may extend to the lower face. The shielding member is configured to shield a rearward side of the rotatable sealing element, proximate the lower face of the cleaner head.

The cleaner head may comprise a roller mounted rotatably with respect to the shielding member, the roller configured to provide a seal between the shielding member and a floor surface.

A rearward side of the shielding member may have a surface configured to guide fluid flow away from rearward side of the rotatable sealing element, proximate the lower face of the cleaner head.

A forward side of the shielding member may have a surface which is coaxial with the rotational axis of the rotatable sealing element.

There may be a clearance between the surface on the forward side of the shielding member and an outer surface of the rotatable sealing element. The clearance may be less than 3mm, and optionally less than 1 mm.

The rotatable sealing element may comprise an outer layer of deformable material.

The rotatable sealing element may comprise a continuous outer layer of deformable material.

The deformable material may be resiliently deformable material.

The deformable material may be closed cell foam.

The rotatable sealing element may comprise a plurality of flexible radially-extending blades or splines in combination with deformable material between the blades/splines. Alternatively, the rotatable sealing element may comprise a plurality of flexible, radially- extending blades without deformable material between the blades/splines.

The cleaner head may comprise a drive configured to rotate the rotatable sealing element independently of movement of the cleaner head across a surface. For example, the drive may be a motor.

The cleaner head may comprise a seal between a side face of the rotatable sealing element and the housing.

The recirculated fluid outlet may have an angle in the range 1 -90 degrees, optionally 20-90 degrees, optionally 45-90 degrees, with respect to the lower surface of the housing.

A lowermost edge of the recirculated fluid outlet may be configured to lie flush with a porous floor surface and spaced from a non-porous floor surface.

The suction passageway may communicate with at least one suction inlet channel, wherein a combination of the suction inlet and the at least one suction inlet channel surround the recirculated fluid outlet. The at least one suction inlet channel may be located proximate a perimeter of the cleaner head.

The cleaner head may comprise a brush seal located at a perimeter of the cleaner head on at least one of: side edges of the cleaner head; rear edge of the cleaner head.

The brush seal may be adjustable in height.

The cleaner head may comprise a sealing element to provide a seal between the housing and the rotatable sealing element.

The sealing element may be located on a rearward side of the rotatable sealing element, within the housing.

The sealing element may be configured to scrape debris from an outer surface of the rotatable sealing element.

The cleaner head may comprise a scraper which is configured to scrape debris from an outer surface of the rotatable sealing element.

The cleaner head may comprise an agitator mounted within the housing. The agitator may be located between the recirculated fluid outlet and the shielding member. The suction passageway may be located between the agitator and the rotatable sealing element.

The agitator may be configured to rotate in a direction towards the suction passageway.

The cleaner head may comprise an agitator and an agitator housing which partially encloses the agitator. The agitator housing may have an opening on a front side, the opening defined by a lip of the agitator housing. The shielding member may extend to a height which is substantially the same as the lip of the agitator housing.

The agitator may be a beater bar or a brush bar.

In any of the examples, the fluid may be air, water, cleaning fluid, or some other fluid. Typically, the fluid will be air.

The cleaner head may be used with any type of vacuum cleaner, such as: an upright cleaner; a cylinder (canister) cleaner; a stick-vac; a hand-held cleaner; a robotic cleaner.

Another aspect provides a vacuum cleaner comprising a cleaner head as described or claimed.

The preferred features may be combined as appropriate, as would be apparent to a skilled person, and may be combined with any of the aspects of the invention. Brief Description of the Drawings

Embodiments of the invention will be described, by way of example, with reference to the following drawings, in which:

Figure 1 shows a vacuum cleaner with a cleaner head;

Figure 2 shows a front view of the cleaner head of Figure 1 ;

Figure 3 shows a cross section of the cleaner head of Figure 2;

Figure 4 shows a cross section of the cleaner head, illustrating pick up of debris;

Figure 5A shows a view of the underside of the cleaner head;

Figures 5B and 5C show detail of the housing in the region where the rotatable sealing element is located;

Figure 6 shows a cross section of the cleaner head, illustrating an alternative form of the rotatable sealing element;

Figure 7 shows a cross section of the cleaner head, illustrating an alternative form of the rotatable sealing element;

Figure 8 shows a cross section of the cleaner head, illustrating operation on a non- porous floor surface;

Figure 9 shows a cross section of the cleaner head, illustrating operation on a porous floor surface;

Figure 10 shows another cross section of the cleaner head of Figure 2, illustrating detail of the recirculated fluid outlet;

Figure 1 1 shows a cross section of an alternative form of the cleaner head without an agitator and without a shielding member;

Figures 12A and 12B schematically show possible configurations of a perimeter inlet and brush seals;

Figure 13 shows an underside of the cleaner head, illustrating airflow from the recirculated fluid outlet to the suction passageway;

Figure 14 shows features at the recirculated fluid outlet and perimeter inlet;

Figures 15 and 16 show an underside of the cleaner head, illustrating airflow from the recirculated fluid outlet to the suction passageway.

Common reference numerals are used throughout the figures to indicate similar features. Detailed Description

Embodiments of the present invention are described below by way of example only. These examples represent the best ways of putting the invention into practice that are currently known to the Applicant although they are not the only ways in which this could be achieved. The description sets forth the functions of the example and the sequence of steps for constructing and operating the example. However, the same or equivalent functions and sequences may be accomplished by different examples.

Figure 1 shows a vacuum cleaner 1 comprising a cleaner head 10, a separation system 2, a suction source 3 and two ducts 7, 8 which connect to the cleaner head 10. The separation system 2 and the suction source 3 may be housed within a housing 6. The vacuum cleaner 1 comprises a handle 9 for pushing the cleaner head across a floor surface.

One of the ducts 7 is fluidly connected to the cleaner head 10 and to the separation system 2. Duct 7 is configured to carry dirt-laden fluid (e.g. air) from the cleaner head 10 to the separation system 2. Duct 8 is fluidly connected to the cleaner head 10 and to the suction source 3, or to the separation system 2. Duct 8 is configured to carry cleaned fluid (e.g. air) from the suction source 3, or from the separation system 2, back to the cleaner head 1 0 to be recirculated. Ducts 7, 8 may be flexibles hoses, rigid pipes or any other type of fluid-carrying duct.

The separation system 2 is configured to separate dirt/dust/debris from the fluid received via duct 7. The separation system 2 can be of any kind, such as a filter bag, a cyclonic separation system (with one or more cyclonic separation stages), a water filter, an electrostatic filter. The separation system may comprise a porous filter, or may not comprise a porous filter. The suction source 3 may comprise an electrical motor 4 and an impeller 5. The suction source 3 may be located downstream of the separation system 2, or the suction source 3 may be located upstream of the separation system 2. Locating the suction source 3 downstream of the separation system 2 is advantageous, as the suction source operates upon cleaned fluid (air) rather than dirt-laden fluid. The "fluid" that is carried along duct 7 and back along duct 8 may be air. Alternatively, the fluid may be water, a cleaning fluid, or some other fluid.

Figure 2 shows the cleaner head 1 0 with ducts 7, 8. Note that whilst the drawings show two separate ducts 7, 8 which are offset from each other laterally across the width of cleaner head 10, the ducts 7, 8 may alternatively be coaxial, or the ducts 7, 8 may be offset in other directions from each other, such as behind one another.

Figure 3 shows a cross-section A-A through the cleaner head of Figure 2. The cleaner head 10 comprises a housing 1 1 . The housing 1 1 has a lower face 12. This is often called a sole plate. The lower face is the part of the cleaner head 10 which faces a floor surface. The lower face 12 comprises a frame of the housing 1 1 with apertures defined in it to allow air flow to/from the floor surface, and to allow components such as the rotatable sealing element 40 and an agitator 60 to make contact with the floor surface. The lower face 12 is configured to move across a surface to be cleaned. The housing may comprise one or more wheels 16, rollers or other features to assist movement of the cleaner head 10 across a floor surface.

The cleaner head 10 comprises a suction inlet 20 defined in the lower face (sole plate) 12 of the housing. There is a suction passageway 20A through the housing 1 1 . The suction passageway 20A is in fluid communication with the suction inlet 20 and with the duct 7. The cleaner head 10 comprises a recirculated fluid outlet 30 which is fluidly connected to the duct 8 (not shown in Figure 3). The recirculated fluid outlet 30 is configured to direct recirculated fluid outwardly from the lower face 12 towards the floor surface.

The cleaner head 10 comprises a rotatable sealing element 40 located at a front of the housing 1 1 . The rotatable sealing element 40 is configured for rotation about a rotational axis 41 . For example, the rotatable sealing element 40 may be supported by the housing 1 1 at each end. The rotational axis 41 is parallel to the lower face 12 of the cleaner head. The housing 1 1 at least partially surrounds the rotatable sealing element 40. In this example, the housing 1 1 surrounds an upper portion of the rotatable sealing element 40, above the rotational axis 41 . A lower portion of the rotatable sealing element 40 is configured to make contact with the surface to be cleaned. The front of the rotatable sealing element 40 is exposed, allowing the rotatable sealing element 40 to serve as a bumper when the cleaner head 10 pushes against an upright object, such as a skirting board or furniture.

In the example of Figure 3 the rotatable sealing element 40 is in the form of a roller with a continuous outer layer of resiliently deformable material. The resiliently deformable material may be a closed-cell foam or other elastomeric material, such as polyurethane. A material such as closed cell foam is advantageous as the material is non-porous, and therefore blocks fluid flow. However, the closed-cell material is resiliently deformable, i.e. it can be deformed from an initial state to accommodate debris and then return to its initial state after the debris has been removed. The rotatable sealing element 40 can form a seal between the cleaner head 10 and a surface to be cleaned. On non-porous surfaces, such as hard floors, the rotatable sealing element 40 can form a seal, or partial seal, to prevent leakage of recirculated fluid from the cleaner head 10. In the case of porous surfaces, such as carpets, recirculated fluid is faced with a first possible flow path towards the suction inlet 20 and a second possible flow path under the shielding member 50 and the rotatable sealing element 40. As the second flow path is a higher resistance path than the first flow path, most of the recirculated fluid should follow the first flow path towards the suction inlet 20. The rotatable sealing element 40 can allow debris to enter the cleaner head 10, rather than pushing the debris in front of the cleaner head, while also maintaining a seal.

Figure 3 shows the cleaner head comprising an agitator, such as a beater bar (brush bar) 60. In other examples, the agitator 60 may not be present. A drive, such as an electric motor, is provided to drive the agitator 60. The drive for the agitator 60 may be turned on and off, such as by a switch on the vacuum cleaner. For example, a user may choose to switch the agitator off when cleaning hard floors, where there is not a need to "beat" the carpet. A single drive may be provided for both the agitator 60 and the rotatable sealing element 40, with transmission to distribute motor power to the agitator 60 and the rotatable sealing element 40.

The cleaner head shown in Figure 3 comprises a shielding member 50. The shielding member 50 is located between the recirculated fluid outlet 30 and the rotatable sealing element 40. The shielding member 50 extends substantially to the level of the lower face 12 of the housing. The shielding member 50 extends across the width of the cleaner head. The shielding member 50 is configured to shield a rearward side of the rotatable sealing element 40, proximate the lower face 12 of the cleaner head. The shielding member 50 shields the rearward lower portion of the rotatable sealing element 40 from air from the recirculated fluid outlet 30. The shielding member 50 also has a function of guiding debris which enters the cleaner head via two possible routes: (i) a route via the rotatable sealing element 40; and (ii) a route via agitation by the recirculated fluid from outlet 30 and suction of suction inlet 20 (optionally with additional agitation by beater bar 60). The shielding member prevents negative interaction between the two paths in the region proximate the floor surface. From Figure 3, it can be seen that the suction inlet 20 is located between the recirculated fluid outlet 30 and the rotatable sealing element 40. The suction passageway 20A is in fluid communication with a portion of the rotatable sealing element 40 above the shielding member 50. This allows debris to be carried towards duct 7 by fluid flow through the suction passageway 20A.

A feature of the cleaner head 10 shown in Figure 3 is that the recirculated fluid outlet 30 is directed towards the surface to be cleaned, thereby allowing the recirculated fluid to perform a useful function in agitating the surface to be cleaned. Another feature of the cleaner head 10 shown in Figure 3 is that both large debris (e.g. debris lying on, or close to, the surface to be cleaned) and small debris/dust can enter the cleaner head 1 0. This eliminates the need to lift the cleaner head 10 off the surface whilst passing over debris, thus preventing leakage of the recirculated fluid and causing scattering of dust/debris. The recirculated fluid outlet can force air through the carpet pile to achieve cleaning efficiency above that of an equivalent conventional suction-only cleaner. In the example shown in Figure 3 the recirculated fluid outlet terminates at the lower face 12 of the cleaner head. Depending on the type of floor surface, the lower face 12 may rest on the floor surface (e.g. on carpets) or may be spaced a small distance above the surface (e.g. on hard floors). In other examples, the recirculated fluid may terminate above the lower surface 12 of the housing.

Figure 4 shows operation of the rotatable sealing element 40 to pick up debris 49. As the cleaner head 10 is moved across a surface to be cleaned, the rotatable sealing element 40 deforms to allow the debris 49 to pass under the rotatable sealing element 40. A seal is maintained between the rotatable sealing element 40 and the surface. The rotatable sealing element 40 deforms as the cleaner head 10 passes over uneven surfaces, to maintain a seal. Debris 49 is guided into the suction passageway 20A via two possible routes: (i) through the front of the cleaner head 10 via the rotatable sealing element 40; and (ii) from the action of the optional beater bar 60 on the surface. The rotatable sealing element 40 rotates in a clockwise direction, as shown by the arrow in Figure 4. Debris 49 which enters the cleaner head via the rotatable sealing element 40 is 'trapped' between the rotatable sealing element 40 and a forward side 52 of the shielding member 50. As the rotatable sealing element 40 continues to rotate, the debris is released when the debris clears the top 54 of the shielding member 50. The deformable properties of the rotatable sealing element 40 have the effect of "pushing" debris radially outwards (towards the left in Figure 4) when the debris clears the top 54 of the shielding member 50. This pushes the debris into the airflow path along the suction passageway 20A. Debris is carried along the suction passageway 20A by a combination of suction and the recirculated fluid flow which enters the suction inlet 20 and is deflected along the suction passageway 20A by the rearward side 53 of the shielding member 50.

In the example shown in Figure 4 a surface on the forward side 52 of the shielding member 50 is coaxial with the rotational axis 41 of the rotatable sealing element 40. The surface on the forward side 52 of the shielding member 50 can have a clearance with respect to the outer surface of the rotatable sealing element 40. An example range for the clearance is 0.5-3mm. Providing a clearance can allow debris to transfer to suction passageway 20A without falling down, or jamming the rotation of, the rotatable sealing element 40.

Figure 4 shows a cleaner head with an agitator (beater bar) 60. The agitator is located within an agitator housing 61 . The agitator housing 61 partially encloses the agitator 60. The agitator housing 61 surrounds the agitator on the rear face, top and part of the front face of the agitator. The agitator housing 61 has an opening on the front side. The opening in the agitator housing 61 is defined by an edge or lip 62. The suction passageway 20A extends from the suction inlet 20, through the lower part of the agitator 60 and through the opening in the agitator housing 61 beneath lip 62. In some examples, the highest point 54 of the shielding member 50 can be level with, or at a similar level to, the lip 62. This can help to ensure large debris is transferred to the fluid flow through the suction passageway 20A and carried towards the duct 7. If the highest point 54 of the shielding member 50 is lower than lip 62 there is a higher possibility that large/heavy debris which is transferred via the rotatable sealing element 40 may drop downwards towards the agitator 60 when it is released from the rotatable sealing element 40. The highest point 54 of the shielding member 50 can be higher than lip 62, but debris has a longer path to travel before it is released from the rotatable sealing element 40.

The beater bar 60 rotates in a direction towards the suction passageway 20A. This is against the direction of forward motion of the cleaner head (i.e. the beater bar 60 rotates anti- clockwise in Figure 4). Stated another way, the beater bar rotates such that bristles are driven down from the back of the beater bar, and rotated towards the front of the cleaner head. This direction of rotation parts carpet pile if carpet is present and guides debris forwards towards the suction passageway 20A. This direction of rotation is opposite to conventional cleaner heads, where the beater bar typically rotates with the direction of forward motion of the cleaner head.

A seal 48 extends parallel to the rotational axis 41 of the rotatable sealing element 40. The seal 48 extends along the length of the rotatable sealing element 40. The seal 48 forms a seal between the housing 1 1 and the rotatable sealing element 40, thereby preventing leakage of air between the housing and the top of the rotatable sealing element 40. The seal 48 also acts as a scraper. The seal 48 is in contact with the outer surface of the rotatable sealing element 40 and can scrape debris from the outer surface of the rotatable sealing element 40. In another example, a scraper may be provided separately from the seal 48. A portion 55 of the rotatable sealing element 40 between the top 54 of the shield and below the seal 48 is in fluid communication with the suction passageway 20A.

In Figures 3 and 4 the shielding member 50 comprises an auxiliary roller 51 . The auxiliary roller 51 has the same length as the shielding member 50 such that the auxiliary roller extends across the width of the cleaner head 10.

The purpose of the auxiliary roller 51 is to provide an additional seal. Roller 51 provides a second line of sealing. In the absence of the auxiliary roller 51 , when the rotatable sealing element 40 deforms to accommodate larger debris (e.g. greater than 1 mm mean diameter), the seal formed between the rotatable sealing element 40 and the surface to be cleaned may be compromised enough to allow a (small) detrimental leak path underneath the shielding member 50 and out of the cleaner head 10. The addition of the auxiliary roller 51 helps to seal the cleaner head, even when the rotatable sealing element 40 deforms to allow debris to pass. Small debris (e.g. 1 mm or less mean diameter) can pass under the auxiliary roller 51 of the shielding member 50. The small debris will be acted upon by the beater bar 60. In a similar fashion to the rotatable sealing element 40, the auxiliary roller 51 can deform to accommodate this small debris and bring it into the cleaner head 1 0.

The shielding member 50 is shown in the drawings as a single element with a forward side 52, a rearward side 53 and a base with a roller 51 . In other examples, the shielding member 50 can be implemented as a single wall, or as a pair of separate walls 52, 53 which extend laterally across the housing 1 1 . Advantageously, wall 52 should be continuous with wall 53 in region 54 so that debris cannot fall into a gap between the walls 52, 53. A surface on a forward side 52 of the shielding member 50 may be vertical, but a surface which is coaxial with the rotational axis 41 of the rotatable sealing element 40 has advantages of improved sealing and of guiding debris to a higher position within the cleaner head.

The rotatable sealing element 40 can be driven in one direction (forwards, clockwise in Figure 4) by an electric motor, or it can rotate in either direction by friction between the rotatable sealing element 40 and the surface to be cleaned.

Figure 5A shows a view of the underside of the cleaner head 10. Figures 5B and 5C show detail of the housing in the region where the rotatable sealing element 40 is located. Figure 5B shows part of the housing 1 1 which fits alongside one end of the rotatable sealing element 40. In Figures 5A-5C the rotatable sealing element 40 is missing, to more clearly show detail of sealing in this area. A seal 14 fits between a side face of the rotatable sealing element 40 and the housing 1 1 . The seal 14 reduces, or prevents, leakage of air around the side of the rotatable sealing element 40.

Some other possible forms of the rotatable sealing element 40 are shown in Figures 6 and 7. Figure 6 shows a rotatable sealing element 40 comprising a core 44 with flexible/deformable radial elements 45 extending radially from the core 44. Radial elements 45 resemble blades or paddles. The blades 45 have the same, or similar, length as the core 44, so that the blades 45 across the full length of the core 44. The blades 45 extend a radial distance such that outer edges of the blades 45 can contact a floor surface. Optionally, the blades 45 can extend a radial distance such that they sweep against the forward side 52 of the shielding member 50 and the part 13 of the housing hood which surrounds the upper portion of the rotatable sealing element 40. The blades 45 sweep larger debris into the cleaner head whilst maintaining a seal to the surface to be cleaned. In this example, the seal 48 may be provided, or may be omitted, as the blades provide a seal to the housing. A scraper may be provided, or may be omitted.

Figure 7 shows a rotatable sealing element 40 which is a hybrid of the designs of Figures 3 and 6. A roller 46 (e.g. of resiliently deformable material) has a smaller diameter compared to the one shown in Figure 3. Radial elements 47 project radially beyond an outer surface of the roller 46. The radial elements 47 will be called splines. Outer edges of the splines 47 can contact a floor surface. Optionally, the splines 47 can extend a radial distance such that they sweep against the forward side 52 of the shielding member 50 and the part 13 of the housing hood which surrounds the upper portion of the rotatable sealing element 40. The splines 47 sweep larger debris into the cleaner head whilst maintaining a seal to the surface to be cleaned. The roller 46 can deform to accommodate larger debris and/or uneven floor surfaces. In this example, the splines are spaced sufficiently regularly such that one spine is always forming a seal. In this example, the seal 48 may be provided, or may be omitted, as the splines provide a seal to the housing. A scraper may be provided, or may be omitted.

Figures 8 and 9 show the cleaner head 10 on different types of floor surface. Figure

8 shows the cleaner head 10 on a non-porous floor surface, such as a hard floor (e.g. wood floor, concrete, linoleum, tiles). Figure 9 shows the cleaner head 10 on a porous floor surface, such as carpet. Referring first to Figure 8, the lower surface 12 of the housing of the cleaner head is spaced a small distance above the non-porous floor surface. This spacing is achieved by a combination of: the wheels 1 6 at the rear of the housing; the auxiliary roller 51 ; and the rotatable sealing element 40. The recirculated fluid exhaust duct 30 is also offset a small distance from the surface to be cleaned. This allows an unobstructed airflow path between the recirculated fluid exhaust duct 30 and the suction inlet 20. The spacing can be a distance of, for example, 1 mm between the lowest extent of the frame of the lower face 12 and the floor surface. More generally, this distance can be in the range of, for example, 0.5mm to 3mm. As described previously, with reference to Figure 4, debris can enter the cleaner head via two possible routes: (i) a route via the rotatable sealing element 40; and (ii) a route via agitation by the recirculated fluid from outlet 30 and suction of suction inlet 20 (optionally with additional agitation by beater bar 60). A seal is maintained around a perimeter of the cleaner head 10 by the rotatable sealing element 40 (front) and brush seals (rear, sides). The rear brush seal 26 is shown in Figure 8. The perimeter seal prevents scattering of dust/debris by fluid from the recirculated exhaust duct 30.

Figure 9 shows the cleaner head 10 on a carpeted floor surface. The lower face 12 of the housing contacts the surface. In effect, the lower face 12 rides along the floor surface. Wheels 1 6, auxiliary roller 51 and the rotatable sealing element 40 sink into the carpet. Optionally, the brush seals 26 can retract, as shown in Figure 9, or if fixed sink into the carpet pile. The recirculated fluid exhaust duct 30 contacts the floor surface and can agitate the carpet pile by blowing fluid into the pile. There is a flow path between the recirculated fluid exhaust duct 30 and the suction inlet 20 through the pile of the porous floor surface. As described previously, with reference to Figure 4, debris can enter the cleaner head via two possible routes: (i) a route via the rotatable sealing element 40; and (ii) a route via agitation by the recirculated fluid from outlet 30 and suction of suction inlet 20 (optionally with additional agitation by beater bar 60). Figure 1 0 shows a cross section through the cleaner head 10 along B-B of Figure 2. The recirculated fluid duct 8 transitions to the recirculated fluid exhaust outlet 30. The recirculated fluid exhaust outlet 30 terminates close to the contact point of the beater bar 60, and extends across as much of the width of the cleaner head as is practicable and a width W. In some examples, the overall area of the recirculated fluid exhaust duct 30 is equivalent to the area of the duct 8. In some examples, the overall area of the recirculated fluid exhaust duct 30 is also equivalent to the area of the dirty fluid duct 7, but the area could be smaller or larger than the area of dirty fluid duct 7.

On a porous floor surface, such as carpet, the recirculated fluid exhaust slot 30 will terminate into the face of the surface (at the same level as the surface, or at some penetration), thereby requiring all recirculated air to travel through the carpet, under edge 31 , to reach the inlet duct 20. In this way the recirculated fluid provides additional dust-pickup. Edge 31 and/or edge 22 can terminate above the surface of the carpet, such as within 2mm of that surface, but dust pick-up performance may be diminished as less recirculated fluid passes through the carpet but, instead, takes the shorter/lower resistance path above the floor surface.

The angle of the recirculated fluid exhaust outlet 30 to the floor surface can be in the range of, for example, 1 to 90 degrees. Advantageously, the angle of the recirculated fluid exhaust outlet 30 to the floor surface is steeper so as to direct more of the flow directly towards the floor surface. In the example shown in the drawings, the angle of the recirculated fluid exhaust outlet 30 is 60 degrees with respect to the lower face 12 of the cleaner head.

Figure 1 1 shows an example of the cleaner head 10 without the beater bar 60 or other form of agitator and without shielding member 50 and auxiliary roller 51 . This reduces at least one of: power consumption ; operating noise; complexity; cost. The cleaner head 10 without the agitator 60, shielding member 50 and auxiliary roller 51 will have lower intrinsic cleaning performance but the benefits of air recirculation and ability to seal the air within the cleaner head 10 whilst permitting large debris are still maintained. Figure 1 1 shows a different suction passageway. The cavity previously occupied by the agitator 60 is reduced in volume. The optional shielding member 50 is removed from this example, and a wall 63 is provided, closer to the surface to be cleaned. Wall 63 could be, for example, within 2mm of the lower face of the housing. A forward wall 64 of the suction passageway 20A is moved closer to the rear side of the rotatable sealing element 40. This exposes the rear side of the rotatable sealing element 40 to suction within the suction passageway 20A and still allows passage of air and debris from the recirculated fluid duct 30. It will be understood that the suction passageway can have a different shape to the one shown here. The cleaner head without agitator may include a shielding member 50 adjacent the rotatable sealing element 40. Figure 12A schematically shows the underside of the cleaner head 10. A suction inlet channel 21 is provided around the perimeter of the cleaner head 10. The perimeter suction inlet channel 21 is generally U-shaped', with a portion along the back of the cleaner head and portions along the sides of the cleaner head. Figure 12A also shows the main suction inlet 20. A combination of the main suction inlet 20 and the perimeter suction inlet channel 21 surround the recirculated fluid exhaust outlet 30. Brush seals 25, 26, 27 extend from the cleaner head 1 0 onto the surface to be cleaned, in order to prevent scatter of any heavier dust not captured by the perimeter suction inlet channel 21 .

Figure 12B schematically shows another example of the underside of the cleaner head 10. The order of the perimeter suction inlet 21 and the brush seals 25, 26, 27 is reversed. In Figure 12B the brush seals are located within the perimeter suction inlet channel 21 . Scattered debris would first have to pass through the brush seals 25, 26, 27 to reach the perimeter inlet.

Figure 13 shows the lower face of the cleaner head housing, and a cross-section through the end of the cleaner head along C-C of Figure 2. The configuration of the suction inlet 21 and brush seals 25, 26, 27 is as shown in Figure 12A. The main suction inlet duct 7 is in fluid communication with a 'U-shaped' perimeter inlet 21 along the back of the cleaner head and along the sides of the cleaner head. A combination of the main suction inlet 20 and the perimeter suction inlet channel 21 surround the recirculated fluid exhaust outlet 30. The arrows on Figure 12 illustrate possible fluid flow paths, with the thicker lines indicating the primary flow paths, and the narrower lines indicating secondary flow paths. The primary flow path is from the recirculated fluid exhaust outlet 30, into the suction inlet 20, around the beater bar 60 (if present) and along the suction passageway 20A (not visible in Figure 12). Secondary flow paths are from the recirculated fluid exhaust outlet 30 and into the perimeter suction inlet channel 21 on the back or sides of the cleaner head. The perimeter suction inlet channel 21 helps to draw any fine dust that may tend to escape from the cleaner head under the influence of the recirculated flow.

Figure 14 shows part of a cross-section through the cleaner head in the region around the recirculated fluid outlet 30 and perimeter inlet channel 21 . The cleaner head is configured to encourage flow along the primary flow path from the recirculated fluid outlet 30 to the main suction inlet 20 and to discourage secondary flow from the recirculated fluid outlet

30 to the perimeter inlet channel 21 . Looking at the possible flow paths from the recirculated fluid outlet 30, the primary flow path has a relatively low resistance path under the forward lip

31 of the recirculated fluid outlet 30 to reach the housing and the main suction inlet 20. The secondary flow path has a relatively high resistance path under the rear lip 32 of the recirculated fluid outlet 30 and the forward lip 22 of the perimeter inlet channel 21 . Lips 22, 32 are relatively wide, compared to lip 31 , and are configured to make contact with a larger area of the floor surface.

Figures 1 5 and 16 shows fluid flow paths between the recirculated exhaust outlet 30 and the suction inlet duct 7. Figure 13 shows the lower face of the cleaner head housing, and a cross-section through the cleaner head at a position through the suction duct 7. Figure 15 shows the lower face of the cleaner head housing, and a cross-section through the cleaner head at a position through the recirculated fluid duct 8. As described above for Figure 13, the main flow path is from the recirculated fluid exhaust outlet 30, into the suction inlet 20, around the beater bar 60 (if present) and along the suction passageway 20A (not visible in Figure 13). Other possible flow paths are from the recirculated fluid exhaust outlet 30 and into the perimeter suction inlet channel 21 on the back or sides of the cleaner head.

The relative vertical position of the brush seals 25, 26, 27 may be adjusted according to floor type. One form of control is a manually-operated two-state latching mechanism. Other forms of control are possible, including an automatic adjustment to floor type.

The cleaner head 10 comprises a recirculated fluid outlet 30. The vacuum cleaner 1 may have a first operating mode in which recirculation is turned on and a second an operating mode in which recirculation is turned off. When recirculation is turned off, the recirculated fluid outlet 30 will not emit recirculated fluid. A suction source 3 in the vacuum cleaner will still apply suction along fluid duct 7, and the cleaner head will still provide cleaning action via the suction passageway 20A and via the suction inlet 20.

The vacuum cleaner 1 may be battery powered (cordless) or mains powered. The motor (4, Figure 1 ) may have a motor power, for example, of up to 600 Watts. At this level of power the rate of temperature increase of the fluid that is continuously circulated is low enough that no overheating problems are encountered in the usual On' duty cycle of 30 minutes.

Some other possible alternative examples will now be described.

Referring again to Figure 3, an upper part of the rotatable sealing element 40 is covered by the housing 1 1 . In another example, the upper part of the rotatable sealing element 40 may be exposed. The housing may extend as far as, or just beyond, the seal 48.

Referring again to Figure 4, there is a portion 55 of the rotatable sealing element 40 between the top 54 of the shield and below the seal/scraper 48 which is exposed to suction in the suction passageway 20A. This portion 55 of the rotatable sealing element 40 is close to the suction passageway 20A. In another example, the portion 55 of the rotatable sealing element 40 may be located further away from the suction passageway 20A. A downward incline (chute) may connect the portion 55 of the rotatable sealing element 40 to the suction passageway 20A. It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages.

Any reference to 'an' item refers to one or more of those items. The term 'comprising' is used herein to mean including the method blocks or elements identified, but that such blocks or elements do not comprise an exclusive list and a method or apparatus may contain additional blocks or elements.

The steps of the methods described herein may be carried out in any suitable order, or simultaneously where appropriate. Additionally, individual blocks may be deleted from any of the methods without departing from the spirit and scope of the subject matter described herein. Aspects of any of the examples described above may be combined with aspects of any of the other examples described to form further examples without losing the effect sought.

It will be understood that the above description of a preferred embodiment is given by way of example only and that various modifications may be made by those skilled in the art. Although various embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the scope of this invention.

Claims

1 . A cleaner head for a recirculating vacuum cleaner comprising :

a housing configured to be movable across a floor surface, the housing having a lower face;

a suction inlet defined in the lower face of the housing;

2. A cleaner head according to claim 1 comprising a shielding member located between the recirculated fluid outlet and the rotatable sealing element, wherein the suction passageway is in fluid communication with a portion of the rotatable sealing element above the shielding member.

3. A cleaner head according to claim 2, wherein the shielding member extends to the lower face, the shielding member configured to shield a rearward side of the rotatable sealing element, proximate the lower face of the cleaner head.

4. A cleaner head according to claim 2 or 3 comprising a roller mounted rotatably with respect to the shielding member, the roller configured to provide a seal between the shielding member and a floor surface.

5. A cleaner head according to any one of claims 2 to 4 wherein a rearward side of the shielding member has a surface configured to guide fluid flow away from a rearward side of the rotatable sealing element, proximate the lower face of the cleaner head.

6. A cleaner head according to any one of claims 2 to 5 wherein a forward side of the shielding member has a surface which is coaxial with the rotational axis of the rotatable sealing element.

7. A cleaner head according to claim 6 wherein there is a clearance between the surface on the forward side of the shielding member and an outer surface of the rotatable sealing element.

8. A cleaner head according to claim 7 wherein the clearance is less than 3mm, and optionally less than 1 mm.

9. A cleaner head according to any one of claims 2 to 8 comprising an agitator mounted within the housing, the agitator located between the recirculated fluid outlet and the shielding member.

10. A cleaner head according to claim 9 wherein the suction passageway is located between the agitator and the rotatable sealing element.

1 1 . A cleaner head according to claim 9 or 10 wherein the agitator is configured to rotate in a direction towards the suction passageway.

12. A cleaner head according to any one of claims 9 to 1 1 wherein the agitator is a beater bar.

13. A cleaner head according to any one of claims 9 to 12 comprising an agitator housing which partially encloses the agitator, the agitator housing having an opening on a front side, the opening defined by a lip of the agitator housing, wherein the shielding member extends to a height which is substantially the same as the lip of the agitator housing.

14. A cleaner head according to any one of the preceding claims wherein the rotatable sealing element comprises an outer layer of deformable material.

15. A cleaner head according to claim 14 wherein the deformable material is resiliently deformable material.

16. A cleaner head according to claim 14 or 15 wherein the deformable material is closed cell foam.

17. A cleaner head according to claim 15 or 16 wherein the rotatable sealing element comprises a plurality of flexible radially-extending blades.

18. A cleaner head according to any one of claims 1 to 13 wherein the rotatable sealing element comprises a plurality of flexible, radially-extending blades.

19. A cleaner head according to any one of the preceding claims comprising a drive configured to rotate the rotatable sealing element independently of movement of the cleaner head across a surface.

20. A cleaner head according to claim 1 9 wherein the drive is a motor.

21 . A cleaner head according to any one of the preceding claims comprising a seal between a side face of the rotatable sealing element and the housing.

22. A cleaner head according to any one of the preceding claims wherein the recirculated fluid outlet has an angle in the range 1 -90 degrees, optionally 20-90 degrees, optionally 45- 90 degrees, with respect to the lower surface of the housing.

23. A cleaner head according to any one of the preceding claims wherein a lowermost edge of the recirculated fluid outlet is configured to lie flush with a porous floor surface and spaced from a non-porous floor surface.

24. A cleaner head according to any one of the preceding claims wherein the suction passageway communicates with at least one suction inlet channel, wherein a combination of the suction inlet and the at least one suction inlet channel surround the recirculated fluid outlet.

25. A cleaner head according to claim 24 wherein the at least one suction inlet channel is located proximate a perimeter of the cleaner head.

26. A cleaner head according to any one of the preceding claims comprising a brush seal located at a perimeter of the cleaner head on at least one of: side edges of the cleaner head; rear edge of the cleaner head.

27. A cleaner head according to claim 26 wherein the brush seal is adjustable in height.

28. A cleaner head according to any one of the preceding claims comprising a sealing element to provide a seal between the housing and the rotatable sealing element.

29. A cleaner head according to claim 28 wherein the sealing element is located on a rearward side of the rotatable sealing element, within the housing.

30. A cleaner head according to claim 28 or 29 wherein the sealing element is configured to scrape debris from an outer surface of the rotatable sealing element.

31 . A cleaner head according to any one of claims 1 to 29 comprising a scraper which is configured to scrape debris from an outer surface of the rotatable sealing element.

32. A vacuum cleaner comprising a cleaner head according to any one of the preceding claims.