Abstract:
A cleaner head for a cleaning appliance, comprising a brushbar, a housing defining a chamber which at least partially surrounds the brushbar, the chamber having a dirty air inlet and a dirty air outlet, and a scraper having a working edge which extends in the longitudinal direction of the brushbar. The scraper is arranged such that, in use, the working edge scrapes debris entrained by the brushbar from the brushbar. The working edge has a profile which is shaped such that debris which accumulates at the working edge is drawn by the airflow through the cleaner head along the working edge towards the dirty air outlet.

Description:
REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to United Kingdom Application No. 1415493.4, filed Sep. 2, 2014, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to a cleaner head for a cleaning appliance and particularly, although not exclusively, relates to a cleaner head for a vacuum cleaner, such as a vacuum cleaner for domestic use. 
       BACKGROUND OF THE INVENTION 
       [0003]    Cleaner heads for vacuum cleaning appliances often comprise a rotatable brushbar for improving debris pickup from carpets. 
         [0004]    Types of debris picked up during cleaning include dust, dirt, food particles and hair Fluff and bundles of hair can be problematic because they can become stuck on the bristles of the brushbar or trapped within the cleaner head. 
       SUMMARY OF THE INVENTION 
       [0005]    According to a first aspect of the present invention there is provided a cleaner head for a cleaning appliance, comprising a brushbar, a housing defining a chamber which at least partially surrounds the brushbar, the chamber having a dirty air inlet and a dirty air outlet, and a scraper having a working edge which extends in the longitudinal direction of the brushbar, the scraper is arranged such that, as the brushbar rotates, the working edge scrapes debris entrained by the brushbar from the brushbar, wherein the working edge has a profile which is shaped such that debris which accumulates at the working edge is drawn by the airflow through the cleaner head along the working edge towards the dirty air outlet. 
         [0006]    The scraper may extend in a generally downward direction within the housing such that the working edge forms a lower edge of the scraper. 
         [0007]    The scraper may be inclined downwardly and forwardly within the housing. 
         [0008]    The dirty air outlet may extend in a plane which extends transversely with respect to the cleaner head. The distance of the working edge from the plane in a direction which is perpendicular to the plane may vary along the working edge. The transverse direction of the cleaner head is the direction perpendicular to the normal direction in which the cleaner head is moved across a surface being cleaned. 
         [0009]    The distance of the working edge from the plane increases along the working edge with respect to a direction which extends away from the dirty air outlet. 
         [0010]    The working edge may be inclined with respect to the plane in which the dirty air outlet extends. 
         [0011]    The working edge may follow a straight line. Alternatively, the working edge may follow a curved line. 
         [0012]    The working edge is arranged such that, when the cleaner head is placed on a flat surface to be cleaned, the distance of the working edge from the surface in a direction which is perpendicular to the surface varies along the working edge. The arrangement would be particularly effective where the dirty air outlet is provided in an upper portion of the housing. 
         [0013]    The dirty air outlet may be positioned centrally with respect to the transverse direction of the cleaner head. The scraper may be positioned rearwardly of the brushbar. The scraper may be rigid. 
         [0014]    The scraper may extend in a plane which is tangential to the brushbar. The scraper may be arranged such that the working edge opposes the direction of rotation of the brushbar. 
         [0015]    According to a second aspect of the invention there is provide a cleaning appliance comprising a cleaner head which is in accordance with the first aspect of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    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: 
           [0017]      FIG. 1  is a perspective view of a cleaner head for a cleaning appliance; 
           [0018]      FIG. 2  is a sectional view of the cleaner head shown in  FIG. 1 ; 
           [0019]      FIG. 3  is a perspective view of part of the cleaner head shown in  FIG. 1  in a first configuration; 
           [0020]      FIG. 4  is a perspective view of part of the cleaner head shown in  FIG. 1  in a second configuration; and 
           [0021]      FIG. 5  is a cross-sectional view of part of a cleaner head corresponding to that shown in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]      FIGS. 1 to 4  show a cleaner head  2  comprising a main body  4  and an agitator in the form of a brushbar  6  supported for rotation by the main body  4 . The brushbar  6  has a rotational axis X. The main body  4  comprises a housing  8  having a chamber  10  (shown in  FIG. 3 ), within which the brushbar  6  is disposed, and an articulated neck  12  which is pivotally connected to the housing  8 . 
         [0023]    The housing  8  has an inlet opening  14  which extends across the underside and the front of the housing  8 . The brushbar  6  is exposed through the opening  14 . The inlet opening  14  provides an inlet to the cleaner head  2  through which air is drawn during use. 
         [0024]    The articulated neck  12  comprises an outlet opening  16  at the end not connected to the housing  8 . The outlet opening  16  provides an outlet from the cleaner head  2 . The articulated neck  12  is connectable to a separator of a vacuum cleaner (not shown) either directly or via a wand or hose, for example. 
         [0025]      FIG. 2  is a sectional view of the cleaner head  2  along the rotational axis X of the brushbar  6 . 
         [0026]    The housing  8  comprises a top portion  18  and first and second side portions  20 ,  22  which define the chamber  10  within which the brushbar  6  is located. Each side portion  20 ,  22  is provided, respectively, with first and second end caps  24 ,  26 . The first end cap  24  is removable from the first side portion  20 . 
         [0027]    The first end cap  24 , which engages with the first side portion  20 , supports a first bearing  28 , for example a roller bearing. The first bearing  28  secured to the first end cap  24  by a bearing retainer  30 . The first bearing  28  supports a first brushbar mount  32  for rotation with respect to the first end cap  24 . The first brushbar mount  32  projects into the chamber  10  and is provided with seals  34 , in the form of o-rings, on an outer surface of the brushbar mount  32 . 
         [0028]    The second side portion  22  is covered by the second end cap  26 . The second side portion  22  comprises a mounting portion  36 , part of which projects into the chamber  10 . A drive housing mount  38  is secured to the mounting portion  36 . The drive housing mount  38  is substantially cylindrical. The drive housing mount  38  supports an elongate drive housing  40  which extends from the drive housing mount  38  further into the chamber  10  along the rotational axis X. A second bearing  42 , such as a roller bearing, is supported by the drive housing mount  38 . The second bearing  42  extends circumferentially about an outer surface of the drive housing mount  38 . The second bearing  42  supports a second brushbar mount  44  for rotation with respect to the drive housing mount  38 . The second brushbar mount  44  is provided with a seal  46 , in the form of an o-ring, on an outer surface of the second brushbar mount  44 . 
         [0029]    The drive housing  40  houses a brushbar motor (only the casing  48  for which is shown) and a transmission  50 . The transmission  50  comprises a gear arrangement  52  and a drive dog  54 . The drive dog  54  protrudes from the end of the drive housing  40  opposite the drive housing mount  38 . 
         [0030]    A collector in the form of a spool  56  is mounted on the mounting portion  36  between the second bearing  42  and the second side portion  22  of the housing  8 . The spool  56  is cylindrical and comprises an outer surface  58  for collecting strands of hair and a circumferential rib  60  at one end for preventing strands of hair that have collected on the outer surface  58  from sliding off the spool  56 . In particular, the rib  60  helps prevent hair from getting tangled with the second bearing  42  or the brushbar motor. 
         [0031]    The spool  56  is slidably mounted on the mounting portion  36  so that it can slide from a hair collecting position in which the spool  56  abuts the second side portion  22  and a hair removal position in which the spool  56  is spaced from the second side portion  22 . 
         [0032]    The spool  56  is provided with slots  62  (see  FIG. 3 ) that engage with ribs  64  provided on the mounting portion  36 . The ribs  64  prevent rotation of the spool  56  when the spool  56  is in the collecting position. 
         [0033]    An abutment feature in the form of a circumferential rib  66  is provided on the drive housing mount  38 . A biasing device in the form of a compression spring  68  is disposed between the rib  66  and the spool  56 . One end of the spring  68  abuts the rib  66  and the other end of the spring  68  abuts the spool  56 . The spring  68  biases the spool  56  into the collecting position and holds the spool  56  firmly against the second side portion  22  of the housing  8 . The rib  66  provides a second function of holding the second bearing  42  in position on the drive housing mount  38 . 
         [0034]    The brushbar  6  comprises a hollow cylindrical body  70  and first and second end plugs  72 ,  74  disposed respectively at each of the ends of the cylindrical body  70 . Each end plug  72 ,  74  has a flange  76 ,  78 , which abuts a respective end of the cylindrical body  70 , and a substantially cylindrical portion  80 ,  82  which protrudes from the flange  76 ,  78  into the cylindrical body  70 . Bristles  83 , which are arranged in circumferentially spaced strips, extend radially outwardly from the cylindrical body  70 . 
         [0035]    The end of the first plug  72  having the flange  76  is open so that the first brushbar mount  32  can be inserted into the first plug  72 . The internal surface of the first plug  72  is contoured, and converges in progressive stepped portions. One of the stepped portions provides a sealing surface  84  against which the seals  34 , provided on the first brushbar mount  32 , seal. The first plug  72  has a socket  86  at the end of the plug  72  opposite the flange  76 . The socket  86  is configured to slidably receive the drive dog  54 . The first plug  72  is secured for rotation with the cylindrical body  70 . 
         [0036]    The second plug  74  is open at both ends so that the mounting portion  36 , drive housing mount  38 , drive housing  40 , second bearing  42  and second brushbar mount  44  assembly, which forms an axle on which the brushbar  6  is supported, can pass through the open ends into the cylindrical body  70 . The second plug  74  is secured for rotation with the cylindrical body  70 . The second plug  74  has an internal sealing surface  88  against which the seal  46 , which is provided on the second brushbar mount  44 , seals. 
         [0037]    During use, air is drawn in through the inlet opening  14 , past the brushbar  6  and out through the outlet opening  16  to the separator of the vacuum cleaner to which the cleaner head  2  is connected. The brushbar motor, which in the embodiment shown is powered by a power source external to the cleaner head  2 , drives the brushbar  6  in rotation via the transmission  50 . In particular, the brushbar motor drives the gear arrangement  52 , which drives the drive dog  54 . The drive dog  54 , which is received by the socket  86 , drives the first plug  72  and hence the brushbar  6  to rotate within the chamber  10 . 
         [0038]    The rotating brushbar  6  agitates debris located on a surface being cleaned, for example debris located between carpet fibres. During cleaning, strands of hair (or other long fibres, such as cotton threads, ribbon etc) may be picked up by the brushbar  6 . Although most strands of hair will be drawn out through the outlet opening  16  to the separator, some will wrap around the brushbar and become trapped. Furthermore, it is expected that strands of hair will work their way over the ends of the brushbar  6  through the gaps between the flanges  76 ,  78  and the first and second side portions  20 ,  22  of the housing  8 . Hair strands which find their way between the gap between the flange  78  of the second plug  74  are wrapped about the outer surface  58  of the spool  56  by rotation of the brushbar  6 . 
         [0039]    The strands of hair collect as a bale around the outer surface  58  of the spool  56 . The rib  60  together with the second side portion  22  prevent the hair from slipping from the spool  56 . As hair accumulates, the thickness of the bail increases until it presses against a region of the inner surface of the second plug  74  which is adjacent the flange  78 . The spool  56  is held rotationally fixed with respect to the mounting portion  36  by engagement of the slots  62  provided in the spool  56  with the ribs  64  on the mounting portion  36 . Consequently, the region of the inner surface of the second plug  74  against which the hair presses forms a braking surface which exerts a braking torque on the brushbar  6 . The braking torque exerted on the brushbar  6  increases as the quantity of hair collected by the spool  56  increases. Once the braking torque exceeds the drive torque transferred to the brushbar  6  by the brushbar motor, the brushbar  6  stalls (i.e. stops rotating). The hair then needs to be removed from the spool  56 . 
         [0040]    The first end cap  24  is removed from the end of the housing  8  together with the first bearing  28 , bearing retainer  30  and first brushbar mount  32  (and seals  34 ). The brushbar  6  is then removed through an aperture in the first side portion  20  along the rotational axis X, thereby exposing the mounting portion  36 , drive housing mount  38 , drive housing  40 , second bearing  42  and second brushbar mount  44 . 
         [0041]      FIG. 3  shows the cleaner head  2  in a first configuration in which the brushbar  6  has been removed and the spool  56  is in the collecting position. 
         [0042]      FIG. 4  corresponds to  FIG. 3 , but shows the cleaner head  2  in a second configuration in which the spool  56  is in the removal position (i.e. the position in which hair can be removed from the spool  56  as described above). The spool  56  is pushed into the removal position shown in  FIG. 4  by sliding the spool  56  along the mounting portion  36 . The stiffness of the spring  68  is such that the spool  56  can be manually moved into the removal position by a user, for example by using fingers. In the removal position, the spring  68  is compressed by the spool  56  against the circumferential rib  66  on the drive housing mount  38 . 
         [0043]    With the spool  56  in the removal position it is readily accessible to a user. In addition, a cutting element such as a pair of scissors or a knife, can be inserted into one of the slots  62  to cut the hair strands from the spool  56 . This allows the hair to be cut-away from the spool  56  readily. Alternatively, the bale of hair could be slid from the outer surface  58  of the spool  56  by sliding the bale of hair from spool  56  onto the ribs  64 . The hair could then be cut by inserting a cutting implement between the ribs  64 . It will be appreciated that the cleaner head  2  could be modified to increase the range of movement of the spool  56  in order to increase the space between the spool  56  and the second side portion  22  in the removal position so that hair that has been slid onto the ribs  64  can be cut-away easily. 
         [0044]    Once the hair has been removed, the spool  56  is released. The spring  68  urges the spool  56  back into the collecting position. The cleaner head  2  can then be reassembled by inserting the brushbar  6  into the chamber  10  over the drive housing  40 , and the first end cap  24  replaced. 
         [0045]    Referring to  FIGS. 3 ,  4  and  5 , the cleaner head  2  further comprises a scraper  90  disposed within the chamber  10  and arranged to extend laterally with respect to the cleaner head  2 . The scraper  90  is fixed to an upper part of the housing  8  and extends downwardly within the chamber  10 . The scraper  90  is inclined slightly forwardly from the upper part of the housing towards the front of the cleaner head  2  and extends in a plane that is tangential with the brushbar  6 . The scraper  90  has a planar front surface  91  and a lower working edge  92  that extends in the longitudinal direction of the brushbar  6  (in particular, the working edge  92  extends in a plane which is parallel with the rotational axis X of the brushbar  6 ). The working edge  92  is arranged to contact the bristles  83  swept past the scraper  90  as the brushbar  6  is rotated such that debris entrained by the brushbar  6  is scraped by the scraper  90  from the bristles  83 . 
         [0046]    The working edge  92  is a profiled edge comprising a central section  94  and first and second lateral sections  96 ,  98 . Each section  94 ,  96  and  98  is straight. Each section  94 ,  96 ,  98  is relatively smooth (i.e. the sections  94 ,  96 ,  98  do not have serrations, notches or protrusions that would inhibit sliding of debris along each section  94 ,  96 ,  98 ). The central section  94  is disposed adjacent a dirty air outlet  100  from the chamber  10 . The dirty air outlet  100  is positioned rearwardly and above the working edge  92  and extends in a transversely extending plane A, as shown in  FIG. 5 . 
         [0047]    The central section  94  extends in a direction which is substantially parallel with the rotational axis X of the brushbar  6  and plane A. The first and second sections  96 ,  98  extend from opposing sides of the chamber  10  towards the central section  94 . Both the first and second sections  96 ,  98  are inclined upwardly within the chamber  10  from the ends which are furthest from the central section  94  towards the central section  94 . 
         [0048]    The distance d of the working edge  92  from the plane A in which the outlet  100  extends in a direction which is perpendicular to the plane A varies along each of the first and second lateral sections  96 ,  98 . In particular, the distance d of the first section  96  from the plane A decreases along the first section  96  with respect to a direction which is generally towards the outlet  100 . Similarly, the distance d of the second section  98  from plane A decreases along the second section  98  with respect to a direction which is generally towards the outlet  100 . 
         [0049]    Debris, such as strands of hair, threads, lint or fluff, caught on the bristles  84  of the brushbar  6  is intercepted by the working edge  92  of the scraper  90  and scraped from the bristles  84 . The debris may, in some instances, slide over the working edge  92  immediately. However, some debris is expected to become caught on the working edge  92 . 
         [0050]    The airflow though the cleaner head  2  exerts a force on debris caught on the working edge  92  in the direction of the dirty air outlet  100 . The inclination of the first and second sections  96 ,  98  means that a substantial component of the force exerted by the airflow on the debris caught on either of the first and second lateral sections  96 ,  98  is in the respective directions in which the sections  96 ,  98  extend. Consequently, a relatively large force is exerted on the debris in the direction of the outlet  100 . The smoothness of the lateral sections  96 ,  98  ensures that the debris is drawn along either the first or second section  96 ,  98  towards the central section  94  and the dirty air inlet  100 . 
         [0051]    It is expected that the force exerted by the airflow increases as the debris gets closer to the outlet  100 . Therefore, in most circumstances, the force exerted on the debris as it reaches the central section  94  will be sufficient to release the debris caught on the working edge  92  so that it can be sucked through the air outlet  100 . 
         [0052]    The profiled working edge  92  enhances the removal of debris scraped from the brushbar  6  by the scraper  90  by providing low resistance to debris that is drawn along the working edge  92  towards the outlet  100 . 
         [0053]    In an alternative embodiment, the first and second sections of the working edge meet adjacent the outlet such that they form an inverted V-shape. The central section would then not be required. 
         [0054]    In a further embodiment, the working edge of the scraper is curved. The working edge may curve upwardly from one or both of the lateral sides of the cleaner head towards the outlet. The curvature of the working edge may be concave.