Abstract:
A cleaner head for a cleaning appliance includes a housing having an upper surface and an underneath surface in which at least on suction opening is formed. The underneath surface has opposing side edges each having a first part which lies adjacent the suction opening or openings and forms a sharply-defined edge with the upper surface and an upwardly curved second part which is located rearwardly of the suction opening or openings. This arrangement is advantageously used in vacuum cleaners or other cleaning appliances in which a ball-type support allows an increased level of steerability involving lateral movement of the cleaner head across the surface to be cleaned. The upwardly curved side edges of the underneath surface of the cleaner head reduce the amount of effort required to achieve the steering by presenting a smoothly curved surface to the carpet or other floor covering.

Description:
REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a national stage application under 35 USC 371 of International Application No. PCT/GB2005/005107, filed Dec. 28, 2005, which claims the priority of United Kingdom Application No. 0500982.4, filed Jan. 18, 2005, the contents of both of which prior applications are incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    The invention relates to a cleaner head for a cleaning appliance, particularly but not exclusively to a cleaner head for a vacuum cleaner. The invention is applicable equally to a cleaner head for an upright vacuum cleaner or a cylinder vacuum cleaner. 
       BACKGROUND OF THE INVENTION 
       [0003]    Vacuum cleaners are now emerging onto the market which have a greater degree of steerability than has previously been the norm. In particular, upright vacuum cleaners which are supported and steered on ball-type rolling members are becoming available, as are cylinder vacuum cleaners which have cleaner heads having ball-type supports to improve manoeuvrability. In some of these arrangements, the act of steering the cleaner head so that it adopts a new direction of movement may cause the cleaner head to travel over the surface being cleaned in a lateral direction in comparison to the normal direction of travel. In these circumstances, the cleaner head can dig into the floor covering, particularly carpets, which increases the effort required successfully to carry out the steering manoeuvre. 
         [0004]    This problem can be reduced by providing curved side edges on a cleaner head. GB 509,528 discloses a vacuum cleaner head which has smoothly rounded lower edges. However, all of the lower edges of the vacuum cleaner head are smoothly rounded which prevents the cleaner head from cleaning effectively at the edges of a room, for example, adjacent to a skirting board. 
       SUMMARY OF THE INVENTION 
       [0005]    It is an object of the present invention to reduce the amount of turning force required to achieve a change in direction of a vacuum cleaner having ball-type steering mechanism whilst still maintaining cleaning performance at the edges of a room. Another object of the invention is to improve the manoeuvrability of vacuum cleaners of the type described above. 
         [0006]    The invention provides a cleaner head for a cleaning appliance comprising a housing having an upper surface and an underneath surface in which at least one suction opening is arranged, the underneath surface having opposing side edges, each side edge comprising a first part which lies adjacent the suction opening or openings and forms a sharply-defined edge with the upper surface and a second part which is located rearwardly of the suction opening or openings and is upwardly curved, characterized in that the cleaner head has a plurality of rearwardly extending portions, each rearwardly extending portion having opposing side edges which are upwardly curved. 
         [0007]    The provision of sharply-defined side edges which lie adjacent the suction opening allows the side wall of the housing adjacent the suction opening to be as slim as possible so that the ability of the cleaner head to pick up dirt and debris from areas close to walls and skirting boards is maximized. 
         [0008]    Further, it has been found by empirical testing that it is the rearmost part of the cleaner head which is most prone to digging into carpets and other fabric floor coverings when the cleaner head moves laterally over the floor surface. The provision of upwardly curved side edges rearwardly of the suction opening or openings allows the cleaner head to present a smoothly rounded face to the floor surface being cleaned as it moves laterally across the floor. The possibility of the cleaner head digging into a carpet or other fabric floor covering is thus reduced. This in turn allows the cleaner head to move across the floor surface more smoothly than has previously been possible so that steering of the vacuum cleaner requires less effort than would otherwise be the case. 
         [0009]    By providing each rearwardly extending portion with upwardly curved opposing side edges, it is ensured that all of the side edges rearwardly of the suction opening present a smoothly rounded surface to the floor covering so as to smooth the lateral movement of the cleaner head across the surface to be cleaned. 
         [0010]    Preferably, the second part of each of the side edges extends along less than one half of the full length of the respective side edge. 
         [0011]    Preferably, one rearwardly extending portion is located at each side of the cleaner head so that one side edge of each rearwardly extending portion forms the second part of each side edge. 
         [0012]    In a preferred embodiment, the upwardly curved second part of each side edge extends to a height of at least one quarter, preferably at least one third, of the rearmost height of the housing. This feature enhances the performance of the cleaner head according to the invention when used on deep pile carpets. 
         [0013]    As has been mentioned above, the cleaner head of the invention is particularly effective when it is used in combination with an upright vacuum cleaner and the upright vacuum cleaner is carried by a rolling support member having an arcuate surface. In these circumstances, the arrangement is such that, when in use the upright vacuum cleaner is caused to turn, the cleaner head travels laterally across the floor surface. The side edges rearwardly of the suction opening then present a smoothly rounded surface to the floor surface and the lateral movement of the cleaner head requires little or no additional effort on the part of the user. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    An embodiment of the invention will now be described with reference to the accompanying drawings, wherein: 
           [0015]      FIGS. 1   a  and  1   b  illustrate known upright and cylinder cleaners respectively in which the invention may be utilized; 
           [0016]      FIGS. 2   a  and  2   b  illustrate the manner in which the upright cleaner of  FIG. 1   a  is steered; 
           [0017]      FIG. 3  is a perspective view of a cleaner head according to the present invention; 
           [0018]      FIGS. 4   a ,  4   b  and  4   c  are side, top and front views respectively of the cleaner head of  FIG. 3 ; 
           [0019]      FIGS. 5   a  and  5   b  are underneath and rear views respectively of the cleaner head of  FIG. 3 ; and 
           [0020]      FIGS. 6   a  and  6   b  are rear views, shown on an enlarged scale, of alternative designs of a rear portion of the cleaner head of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    The vacuum cleaner  10  illustrated in  FIG. 1   a  is an upright cleaner having a main body  12  which includes a handle  14  and dirt and dust separating means  16  for separating dirt and dust from the airflow passing through the vacuum cleaner  10 . In the vacuum cleaner  10 , the dirt and dust separating means  16  operates on the cyclonic principle and includes an upstream, low-efficiency cyclone  18  followed by a plurality of downstream, high-efficiency cyclones  20 . However, for the purposes of the present invention, the nature of the dirt and dust separating means  16  is immaterial. 
         [0022]    The main body  12  is pivotably supported on a rolling support member  22  which has an arcuate surface when viewed in the lateral direction. A cleaner head  24  is pivotably mounted on the support member  22  and air ducts  26 ,  28 ,  30  are provided for conducting air between the cleaner head  24 , the support member  22  and the dirt and dust separating apparatus  16 . A motor (not shown) is mounted inside the support member  22  for drawing an airflow into the cleaner head  24  via a suction opening (located on the underside of the cleaner head  24 ), passing it to the dirt and dust separating apparatus  16  so that the dirt and dust can be extracted therefrom, and exhausting it to the atmosphere via the support member  22  so that the motor therein can be cooled. It is to be noted that the precise configuration of the components is not material to the present invention. 
         [0023]    The type of support member  22  illustrated in  FIG. 1   a  allows the upright vacuum cleaner  10  to be maneuvered in a manner which is different from traditional vacuum cleaners which are normally mounted on wheels having fixed horizontal axes. The manner in which the vacuum cleaner  10  is maneuvered is illustrated in  FIGS. 2   a  and  2   b . In order to steer the vacuum cleaner  10 , the user twists the handle  14  about the axis  32  so as to cause the axis of the support member  22  to tilt. The connection between the cleaner head  24  and the air duct  26  (which is fixed to the main body  12 ) is such that the cleaner head  24  is forced to travel laterally with respect to the normal forwards direction of travel of the cleaner head  24 . Thus the cleaner head  24  moves in the direction indicated by arrow A in  FIG. 2   a  and arrow B in  FIG. 2   b  when it is steered around tight corners. 
         [0024]    A similar arrangement is possible in respect of cylinder vacuum cleaners. A cylinder vacuum cleaner  50  is shown in  FIG. 1   b . The cleaner  50  has a main body  52  which includes some sort of dirt and dust separating means  54  (again shown here as being cyclonic, but this is not important) and a motor. A flexible hose  56  is connected to the main body  52  at one end and to a wand or extension tube  58  at the other end. The cleaner head  60  is attached to the distal end of the wand or extension tube  58 . As with the upright cleaner illustrated in  FIG. 1   a , the cleaner head  60  can be attached to the extension tube  58  using the same principles, namely by providing an arcuate support member  62  whose axis of rotation can be tilted by twisting the extension tube  58  about its longitudinal axis. The connection between the cleaner head  60  and the extension tube  58  then causes the direction of the cleaner head  60  to alter which, in turn, causes the cleaner head  60  to travel laterally with respect to the original forward direction. 
         [0025]    It is this lateral movement across the surface being cleaned which can introduce difficulties in that unnecessary resistance can be encountered making the required movement difficult to achieve. 
         [0026]    A cleaner head  100  according to the invention is illustrated in  FIGS. 3 ,  4   a ,  4   b ,  4   c ,  5   a  and  5   b . The cleaner head  100  has a housing  102  which has an upper surface  104  and an underneath surface  106 . The upper surface  104  and the underneath surface  106  together define the housing  102 . The underneath surface  106 , which can be seen in  FIG. 5   a , is arranged to face towards the surface to be cleaned and has a suction opening  108  formed therein. The suction opening  108  extends across substantially the entire width of the cleaner head  100 . 
         [0027]    The upper surface  104  has an enlarged, generally cylindrical portion  110  extending across the width of the cleaner head  100  and arranged above the suction opening  108  in the underneath surface  106 . This cylindrical portion  110  defines a cavity which is shaped and dimensioned so as to be able to receive and house a rotatable brush bar  109  immediately above the suction opening  108 . Side walls  110   a ,  110   b  are located at the ends of the cylindrical portion  110 . The suction opening  108  extends between the side walls  110   a ,  110   b . The side walls  110   a ,  110   b  are substantially flat or planar so that the suction opening  108  of the cleaner head  100  is as close as possible to the side of the cleaner head  100 . When the side of the cleaner head  100  is positioned close to walls or skirting boards in a room, the collection of dirt and dust from the edge of the room is improved because the suction opening  108  is spaced from the wall or skirting board by only the thickness of the respective side wall  110   a ,  110   b.    
         [0028]    The underneath surface  106  has opposing side edges  106   a ,  106   b  which extend along the lower edges of the sides of the cleaner head  100 . A first part  106   c ,  106   d  of each side edge  106   a ,  106   b  of the underneath surface  106  is formed by the lower end of the respective side wall  110   a ,  110   b . The lower ends of the side walls  110   a ,  110   b  extend alongside the suction opening  108  and have sharply-defined edges which delimit the suction opening  108 . By sharply-defined is meant that the edges are angular and have a minimal radius of curvature. 
         [0029]    A second part  106   e ,  106   f  of each of the side edges  106   a ,  106   b  is located rearwardly of the first parts  106   c ,  106   d . The second part  106   e ,  106   f  of each of the side edges  106   a ,  106   b  of the underneath surface  106  is upwardly curved. By this is meant that the underneath surface  106  is shaped so that, instead of the underneath surface  106  meeting the upper surface  104  at a relatively sharp corner, the upwardly curved second part  106   e ,  106   f  of each the side edges  106   a ,  106   b  presents a smoothly curved surface to the floor surface being cleaned. 
         [0030]    It will be understood that, when the cleaner head  100  is steered so that some lateral movement takes place, then the upwardly curved shape of the second part of the side edge on the side facing the direction of lateral movement will present a smoothly curved surface to the floor being cleaned. This will reduce the amount of user effort required to cause the lateral movement to take place since the floor covering will slide smoothly underneath the cleaner head  100  and the tendency of the cleaner head  100  to dig into the floor covering will be reduced. At the same time, the first part of each side edge can be placed close to a wall or skirting board so that good edge cleaning is maintained. 
         [0031]    The upward curve of the underneath surface  106  is shown in  FIG. 5   b . As can be seen, the shape of the second part  106   e ,  106   f  of each of the side edges  106   a ,  106   b  is rounded with a relatively large radius of curvature compared to the first parts  106   c ,  106   d . The upwardly curved second parts  106   e ,  106   f  of the side edges  106   a ,  106   b  do not extend alongside the suction opening  108  as this could compromise the ability of the cleaner head  100  to pick up dirt and debris adjacent an edge or skirting board. In this embodiment, the upwardly curved second parts  106   e ,  106   f  extend along less than a half of the full length of the side edges  106   a ,  106   b  as can be seen in  FIG. 5   a.    
         [0032]    Immediately in front of the cylindrical portion  110  is a bumper portion  112  which forms part of the upper surface  104 . A debris pick-up slot can be formed immediately behind the bumper portion  112  but this is not relevant to the present invention. Rollers or wheels (not shown) can be provided on the underneath surface  106  adjacent the bumper strip to improve the forward movement of the cleaner head  100  across the surface to be cleaned. 
         [0033]    The upper surface  104  of the housing  102  is shaped so as to define, together with a portion of the underneath surface  106 , a motor housing  114  which is located centrally of the cleaner head  100  behind the cylindrical portion  110 . A motor (not shown) for driving the brush bar  109  is housed inside the motor housing  114  and an appropriate drive belt or direct drive components are provided between the motor and the brush bar  109 . Located on the upper surface of the motor housing  114  is an upstanding connector  115  by means of which the cleaner head  100  is connected to the remainder of the vacuum cleaner in a manner which allows the cleaner head  100  to be steered in the way described above. The type of connection which allows this steering to take place does not form the subject matter of this application and so will not be described any further here. 
         [0034]    Located behind the cylindrical portion  110  and on either side of the motor housing  114  are two rearwardly extending portions  116 ,  118 . Each rearwardly extending portion  116 ,  118  is formed by a rearward portion of the upper surface  104  and a rearward portion of the underneath surface  106 . The height of each of the rearwardly extending portions  116 ,  118  is less than half of the height of the cylindrical portion  110 , although this proportion is not important and can be varied. 
         [0035]    A further improvement in manoeuvrability can be achieved if the interior side edges  116   b ,  118   b  of the rearward portions  116 ,  118  are also upwardly curved since, whenever the cleaner head  100  is moved laterally, the interior side edge of the rearward portion on the side of the cleaner head opposite the direction of movement will become the leading edge for that rearward portion. 
         [0036]    In the embodiment, it is also envisaged that the lower side edges  114   a ,  114   b  of the motor housing  114  will be upwardly curved so that, whenever the cleaner head  100  is caused to move laterally across a surface to be cleaned, each and every leading edge  106   e ,  114   a ,  118   b ;  106   f ,  114   b ,  116   b  will present a smoothly curved surface to the floor surface being cleaned, irrespective of the direction of the lateral movement. In the event that the cleaner head  100  is shaped so that more than two rearwardly extending portions are provided, each rearwardly extending portion will have upwardly extending side edges which present a smoothly curved surface to the floor surface being cleaned. 
         [0037]      FIGS. 6   a  and  6   b  show rear views of two alternative designs of rearwardly extending portion which could be incorporated into the cleaner head described above. In  FIG. 6   a , the rearwardly extending portion  150  has upper side edges  152  which are relatively sharply defined. However, the lower side edges  154  are upwardly curved, as described above. The extent h of the upwardly curved edges  154  is approximately one third of the total height H of the rearwardly extending portion  150 . The alternative design shown in  FIG. 6   b  is similar to that shown in  FIG. 6   a  in that the rearwardly extending portion  160  has relatively sharply defined upper side edges  162  and smoothly curved lower side edges  164 . In this case, though, the extent h of the upwardly curved edges  164  is approximately one half of the total height H of the rearwardly extending portion  160 . 
         [0038]    Either of the rearwardly extending portions  150 ,  160  could be incorporated into the cleaner head  100  described above in place of the rearwardly extending portions  116 ,  118 . Furthermore, variations on these designs could equally be utilized. For example, the gaps between the rearwardly extending portions  116 ,  118  and the motor housing  114  could be omitted so that the rear edge  120  of the housing  102  extends parallel to the front edge of the bumper portion  112 . In such an arrangement, only the outermost side edges of the underneath surface  106  will be upwardly curved.