Abstract:
An accessory for a cleaning appliance includes a head having a housing, a downwardly-directed suction opening in the housing and a neck adapted for attachment to a hose or wand of the cleaning appliance. A rotatable connection is provided between the neck and the head for allowing rotation of the neck relative to the head. A wheel arrangement maneuverably supports the accessory on a surface to be cleaned and is mounted on the neck of the accessory. The wheel arrangement may normally be in contact with the surface to be cleaned, but the point or points of contact between the wheel arrangement and the surface to be cleaned are dependent upon the rotational position of the neck with respect to the head.

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application is a national stage application under 35 USC 371 of International Application No. PCT/GB2005/001571, filed Apr. 22, 2005, which claims the priority of United Kingdom Application No. 0410698.5, filed May 13, 2004, the contents of both of which prior applications are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The invention relates to an accessory for a cleaning appliance, particularly but not exclusively for a vacuum cleaner. 
     BACKGROUND OF THE INVENTION 
     Vacuum cleaners are usually of the upright or cylinder type. Cylinder cleaners consist of a main body containing a motor and fan unit for drawing an airflow into the main body and separating apparatus for extracting dirt and dust from the airflow and retaining it for disposal. The separating apparatus can be a cyclonic arrangement, bags or filters or a combination of these. A hose and wand assembly is connected to the inlet of the main body and an accessory in the form of a floor tool having a suction opening is attached to the end of the wand remote from the main body so that the suction opening can be manoeuvred across the surface to be cleaned by the user. Upright cleaners commonly have a cleaner head permanently attached to the main body of the vacuum cleaner which is manoeuvred, together with the main body, across the surface to be cleaned. However, many upright cleaners can also be operated in the manner of a cylinder machine by having a removable or releasable hose and wand assembly provided to which an accessory such as a floor tool can be attached. 
     In this context, therefore, the term “accessory” is used to mean a tool which can be attached to a hose and wand assembly forming part of a vacuum cleaner, whether the vacuum cleaner is an upright machine or a cylinder machine, for the purpose of cleaning a floor or other surface. The term is also intended to include accessories which can be used with other cleaning appliances such as steam cleaners, floor polishers and the like. 
     Many known floor tools consist of a head having a housing which defines a downward-facing suction opening and a neck which is connectable to the wand of the hose and wand assembly of the cleaner with which the floor tool is to be used. Whilst the neck is rotatably connected to the head to accommodate changes in the position of the wand relative to the head during normal use, the wheel arrangement which allows the head to be manoeuvred across the surface is carried by the head. The floor tool thus has no steering capability and so can be awkward to manoeuvre around obstacles located on the surface to be cleaned such as furniture. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a wheeled accessory for a vacuum cleaner or other cleaning appliance which has improved manoeuvrability in comparison to known accessories. 
     The invention provides an accessory for a cleaning appliance having a head comprising a housing and a downwardly-directed suction opening, a neck adapted for attachment to a hose or wand of the cleaning appliance, a rotatable connection between the neck and the head for allowing rotation of the neck relative to the head, and a wheel arrangement for manoeuvrably supporting the accessory on a surface to be cleaned, characterised in that the wheel arrangement is mounted on the neck of the accessory. 
     Preferably, the wheel arrangement is in contact with the surface to be cleaned and the point or points of contact with the surface to be cleaned are dependent upon the rotational position of the neck with respect to the head. 
     An accessory according the invention is more manoeuvrable than known floor tools and other wheeled accessories. 
     The wheel arrangement can consist of a pair of spaced-apart wheels arranged on either side of the neck, one of the wheels being lifted away from the surface to be cleaned when, in use, the neck is rotated with respect to the head. In this way, the point of contact with the surface to be cleaned can be changed in dependence upon the position of the neck with respect to the head and this improves the ability of the user to steer the accessory around obstacles. 
     In a preferred embodiment, the rotatable connection lies in a plane which is inclined to the surface to be cleaned. This improves the steering capability of the arrangement still further as the head will, in use, turn in response to the user applying a twisting force to the wand. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the invention will now be described with reference to the accompanying drawings, in which: 
         FIG. 1  is a perspective view of an accessory for a cleaning appliance according to the invention; 
         FIG. 2  is an underneath view of the accessory of  FIG. 1 ; 
         FIG. 3   a  is a side view of the accessory of  FIG. 1  in a first position; 
         FIG. 3   b  is a side view of the accessory of  FIG. 1  in a second position; 
         FIG. 4   a  is a rear view of the accessory of  FIG. 1  in normal use; 
         FIG. 4   b  is a rear view of the accessory of  FIG. 1  turning to the right; 
         FIG. 4   c  is a rear view of the accessory of  FIG. 1  turning to the left; and 
         FIGS. 5   a ,  5   b  and  5   c  are rear views of an alternative accessory according to the invention shown in normal use, turning to the right and turning to the left respectively. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1 and 2  show a floor tool  10  which forms an accessory for a vacuum cleaner according to the invention. The floor tool  10  has a head  12  formed by a housing  14  which has a suction opening  16  formed in the lower surface thereof. A rotatable brush bar  18  is supported in the housing  14  immediately above the suction opening  16  so that the bristles or beaters carried by the brush bar  18  project through the suction opening  16  as the brush bar  18  rotates and agitate the surface to be cleaned. The brush bar  18  is driven by means of a turbine  20 , through which air is drawn by the motor of the vacuum cleaner, and a drive belt (not shown). The precise configuration of the housing  14 , the location of the brush bar  18  and the means by which it is driven are immaterial to the present invention and will not be described any further here. 
     The floor tool  10  also includes a neck  22  which has a forward portion  24  and a rearward portion  26 . The forward portion  24  is connected to the head  12  via a rotatable coupling  28  which will be described in more detail below. The forward portion  24  extends generally away from the head  12  and carries two wheels  30  which are rotatably mounted on the forward portion  24 . The rearward portion  26  is pivotably connected to the forward portion  24  about an axis which coincides with the axis  32  about which the wheels  30  rotate. The rearward portion  26  has a collar  34 , projecting away from the forward portion  24 , for receiving a wand or hose attached to the main body of the vacuum cleaner with which the floor tool  10  is to be used. A catch  36  is provided on the rearward portion  26  for the purpose of retaining the hose or wand on the collar  34 , but this can be omitted if desired. 
     The wheels  30  are spaced apart in a lateral direction, ie. in a direction perpendicular to the normal direction of travel of the floor tool  10 , which is indicted by arrow A shown in  FIG. 1 . The wheels  30  thus lie symmetrically on either side of the neck  22  of the floor tool  10  behind the head  12  and behind the rotatable coupling  28 . Each wheel  30  is dimensioned so that, when the suction opening  16  lies parallel to the surface to be cleaned, and the forward portion  24  is substantially horizontal, the wheels  30  are in contact with the surface to be cleaned. This is illustrated in  FIG. 3   a . The wheels  30  thus support the floor tool  10  and allow it to be manoeuvred across the surface to be cleaned  40 . Illustrated in  FIG. 3   b  is the ability of the rearward portion  26  of the neck  22  to pivot with respect to the forward portion  24  about the axis  32 . This movement is necessary to accommodate changes in the inclination with respect to the floor (see arrow B) of a wand (not shown) attached to the collar  34  during normal use in which the floor tool  10  is pushed forwards and pulled backwards across the floor  40 . 
       FIGS. 3   a  and  3   b  also show the rotatable coupling  28  by means of which the neck  22  of the floor tool  10  is attached to the head  14 . The rotatable coupling  28  comprises two concentrically located collars, one located on each of the head  12  and the neck  22 , which are able to rotate with respect to one another. The axis  38  about which the collars are able to rotate is inclined to the surface to be cleaned  40 , see  FIG. 3   b . The reason for the inclination of the axis  38  will be explained in more detail below. 
       FIG. 4   a  shows the floor tool  10  from the rear when it is in normal use. The head  12  lies horizontally on the surface to be cleaned  40  so that the suction opening  16  lies parallel to the floor  40 . When the collar  34  is attached to a hose and wand assembly of a vacuum cleaner and the motor is turned on, an airflow is drawn into the floor tool  10  through the suction opening  16  and dirt and debris is drawn into the floor tool  10  with the airflow. Simultaneously, air is drawn into the floor tool  10  via the turbine  20  so that the brush bar  18  is driven about its axis and the floor covering is agitated so as to release as much dirt and dust as possible from the floor covering. The airflow is passed along the neck  22  of the floor tool to the hose and wand assembly and from there to the separating apparatus of the vacuum cleaner where the dirt and dust are separated and retained whilst cleaned air is returned to the atmosphere. 
     In the position shown in  FIG. 4   a , the wheels  30  of the floor tool  30  are both in contact with the surface  40 . Consequently, the two points of contact with the floor  40  are symmetrically positioned about the centre of the neck  22 . Changes in the angle at which the wand attached to the collar  34  lies with respect to the floor  40  are accommodated by pivotal movement of the rearward portion  26  of the neck  22  as shown in  FIGS. 3   a  and  3   b . However, the fact that the wheels  30  are mounted on the neck  22  means that the wand attached to the collar  34  can be twisted about the longitudinal axis of the wand (which is coincident with the longitudinal axis  42  of the collar  34  shown in  FIG. 3   b ) to effect steering of the floor tool  10 . This is achieved by turning the neck  22  of the floor tool  10  as shown in  FIGS. 4   b  and  4   c . In  FIG. 4   b , the wand is twisted about its axis in a clockwise direction so that the neck  22  is similarly twisted in a clockwise direction about the axis  42 , see arrow C. This results in the left-hand wheel  30   a  being lifted away from the floor  40  so that the only point of contact with the floor  40  is the lower edge of the right-hand wheel  30   b  which is located to the right of the neck  22 . This arrangement having an asymmetrical point of contact (about the centre of the floor tool  10 ) provides a greater steering capacity than the arrangement of  FIG. 4   a  in which the point of contact with the floor  40  is symmetrically arranged about the neck  22 . It allows the floor tool  10  to be turned to the right with greater ease than would be the case if both wheels  30   a ,  30   b  remained in contact with the floor  40 . 
     In a similar manner,  FIG. 4   c  shows the position of the floor tool  10  from the rear when the wand is twisted in an anticlockwise direction, thus causing the collar  34  to twist in an anticlockwise direction about the axis  42 , see arrow D. In this case, the left-hand wheel  30   a  remains in contact with the floor  40  whilst the right-hand wheel  30   b  is lifted away therefrom. As before, the point of contact changes from a symmetrical arrangement to an asymmetrical arrangement with the point of contact now located only to the left of the neck  22 . In this position, the floor tool  10  can be turned to the left with greater ease than would be the case if both wheels  30   a ,  30   b  were in contact with the floor  40 . 
     It will be appreciated that, whilst  FIGS. 4   b  and  4   c  illustrate the neck  22  with the rearward portion  26  in a generally horizontal position, the twisting movement can be carried out with the rearward portion  26  inclined to the vertical as shown in  FIG. 3   b.    
     The rotatable coupling  28  described above allows the neck  22  to rotate with respect to the head  12  in a plane which lies generally perpendicular to the forward direction of travel of the floor tool  10  (illustrated by arrow A in  FIG. 1 ). This is important because, when the neck  22  is turned so as to lift one of the wheels  30  away from the floor  40 , it is highly desirable for the head  12  to remain parallel to the floor so that the suction opening  16  also remains parallel to the floor. If the suction opening were to be tilted, the pick-up performance of the floor tool  10  would be affected, partly because air would be bled into the tool between the housing and the floor, and partly because the brush bar would not operate at its optimum distance from the floor covering. The swivel capability of the rotatable coupling  28  allows the suction opening  16  to remain flat on the floor  40  when the neck  22  of the floor tool  10  is twisted. 
     As has been mentioned above, the rotatable coupling  28  allows the collars of the coupling  28  to rotate with respect to one another about an axis  38  which is inclined to the surface to be cleaned  40 . The reason for this is that, when the wand is twisted about the axis  42  as described above, the inclination of the axis  38  causes the head  12  of the floor tool  10  to turn in the same direction as the twisting action. Thus, if the wand is twisted to the right, as described in connection with  FIG. 4   b , and the left-hand wheel  30   a  is lifted from the ground, the head  12  will turn towards the right, thus increasing the ease with which the floor tool  10  can be steered around obstacles. Similarly, if the wand is twisted to the left so that the right-hand wheel  30   b  is lifted from the ground, the head  12  will turn towards the left and thus the steering capability of the floor tool  10  is improved in that direction. Under these conditions, the head  12  remains flat against the floor  40  so that the suction opening  16  lies parallel to the floor and pick-up performance is not compromised. 
     In the embodiment described above, the tilting of the neck  22  of the floor tool  10  essentially involves lifting one of the wheels  30  away from the floor. In order to facilitate this movement, the cross-sectional shape of the rim of each of the wheels  30  is rounded as shown in  FIGS. 4   a  to  4   c . This minimises the torque required to cause the turning movement to be carried out. However, the lateral position of the point of contact between each wheel  30  and the floor remains approximately the same when the neck  22  is tilted. Nevertheless, the number of points of contact between the wheels  30  and the surface to be cleaned  40  is dependent upon the twisting movement of the wand and thus the rotational position of the neck  22  with respect to the head  12 . 
     A second embodiment of the invention is shown in  FIGS. 5   a  to  5   c . The only differences between the floor tool  110  shown in  FIGS. 5   a  to  5   c  and the previously described embodiment are the size and shape of the wheels  130 . In the second embodiment, the wheels  130  are relatively wide and have a rim  132  which is arcuately shaped in the lateral direction. The rim  132  has a maximum diameter at the point  132   a  closest to the neck  122  and a minimum diameter at the point  132   b  where it merges with the side portion  134  of the wheel  130 . Between the points  132   a  and  132   b , the rim has a cross-section which is part-circular in shape. The remainder of the floor tool  110  is identical with the floor tool  10  described above. When the floor tool  110  is in normal use as shown in  FIG. 5   a , the innermost portions of the rim  132  of each wheel  130  (ie. the points  132   a  of maximum diameter) will be in contact with the surface to be cleaned. 
     When the wand attached to the collar  134  is twisted in the clockwise direction as shown in  FIG. 5   b , the left-hand wheel  130   a  is lifted away from the floor so that there is no point of contact between the wheel  130   a  and the floor. The sole point of contact is thus the rim  132  of the right-hand wheel  130   b . Initially, when the angle of twist is small, the point of contact will remain at or near the point  132   a  of maximum diameter. However, as the angle of twist increases, the point of contact will move towards the point  132   b  of minimum diameter. This is due to the width of the wheels  130  and the arcuate shape of the rim  132 . Similarly, when the wand is twisted in the opposite direction, ie. anti-clockwise, the right-hand wheel  130   b  will be lifted away from the floor and the sole point of contact will be between the rim  132  of the left-hand wheel  130   a , with the position of the point of contact being dependent upon the angle of twist of the wand. As the angle of the twist of the wand increases, so does the manoeuvrability of the floor tool  110 . 
     The invention is not intended to be limited to the precise details of the embodiments described above and variations and modifications will be apparent to a skilled reader. For example, the floor tool need not include a turbine designed to drive the brush bar or, indeed, a brush bar.