Abstract:
The present invention relates to a floor tool for a surface treating appliance including, a sole plate comprising a floor engaging surface having forward and rearward floor contacting edges and a suction opening, a head which is pivotable relative to the sole plate about an articulation axis between forward and rearward positions, the head having a front sole plate engaging edge and a back sole plate engaging edge, and a connecting arm comprising an outlet in communication with the suction opening, at least a portion of the floor engaging surface of the sole plate extends beyond the back sole plate engaging edge of the head when the head is in the rearward position.

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application claims priority of United Kingdom Application No. 0903588.2 filed Mar. 3, 2009, the entire contents of which are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     This invention relates to a floor tool for a surface treating appliance. Particularly, but not exclusively, the invention relates to a floor tool for a vacuum cleaner. 
     BACKGROUND OF THE INVENTION 
     A wide range of vacuum cleaners are available on the market and include upright cleaners, stick vac cleaners, cylinder cleaners and hand-held cleaners. A cylinder vacuum cleaner normally has a main body containing a motor and fan assembly for drawing an airflow into the main body and separating apparatus for separating dirt and dust from the airflow. The separating apparatus may take the form of, for example, a cyclonic separator, a bag or a filter. A hose and wand assembly is connected to the main body and a floor tool is attached to the end of the wand remote from the main body so that it can be maneuvered across the surface to be cleaned. A range of floor tools are often supplied so that a user can choose an appropriate tool for their cleaning task; for example a crevice tool or a brush tool. 
     Many upright vacuum cleaners are provided with releasable hoses or wands so that they are able to operate in the manner of a cylinder machine. Floor tools are thus often provided with upright machines as well. 
     Handheld vacuum cleaners are provided with a nozzle which may be rigid or flexible. A range of floor tools may be supplied so that a user can choose an appropriate tool for their cleaning task. 
     Floor tools generally comprise a head having a lower surface, commonly known as a soleplate. A suction opening is formed in the soleplate through which, in use, dirt and dust is drawn into the floor tool from the floor surface. It is useful for the head to be pivotally connected to the sole plate so that the head or the soleplate can rock back and forth as the floor tool is pushed and pulled across the floor surface. The rocking motion allows the suction opening to remain in close proximity to the floor surface when the floor tool is pushed or pulled across the floor surface. The rocking motion is particularly advantageous on carpeted surfaces because it can cause parts of the soleplate to agitate the carpet. 
     Although agitation is desirable in most instances, a problem can arise with such floor tools, namely that as the floor tool is pulled backwards along a floor surface the rearward floor contacting edge of the sole plate can act as a pivot point against the floor. In some circumstances the cleaner head will pivot about this rearward floor contacting edge causing the cleaner head to “skip” backwards. This problem can be more apparent on long pile carpets because as the floor tool starts to pivot about the pivot point the rearward floor contacting edge of the sole plate can dig into the carpet pile causing more skipping. A solution to this problem is therefore desirable. 
     Existing arrangements illustrating floor tools which attempt to deal with this problem are shown in EP 0353546, EP 0304609 and WO 03/039315. 
     EP 0353546 discloses a floor tool which has a set of floor-engaging wheels and a soleplate. The duct connecting the head to the wand has a pivot point located directly above the axis of the wheels so that, when a user pushes forward on the wand, a downwardly-acting moment about the axis of the wheels pushes the soleplate onto the floor surface. EP 0304609 discloses a floor tool having a complicated arrangement of pivots which forces the head of the floor tool to rock back and forth when the floor tool is pushed back and forth across a floor surface. WO 03/039315 discloses a floor tool having a connecting duct which is pivoted in two locations relative to the soleplate. 
     In order to operate effectively, the above arrangements all require complicated and therefore expensive pivot point arrangements. Consequently, a more simple solution to the problem of skipping would be desirable. 
     SUMMARY OF THE INVENTION 
     Accordingly the present invention provides a floor tool for a surface treating appliance comprising,
         a sole plate comprising a floor engaging surface having forward and rearward floor contacting edges and a suction opening,   a head which is pivotable relative to the sole plate about an articulation axis between forward and rearward positions, the head having a front sole plate engaging edge and a back sole plate engaging edge, and   a connecting arm comprising an outlet in communication with the suction opening,   wherein at least a portion of the floor engaging surface of the sole plate extends beyond the back sole plate engaging edge of the head when the head is in the rearward position.       

     In the present invention the pivot point about which the floor tool may pivot and thus “skip” against a floor surface is a rear edge of the portion and/or the rearward floor contacting edge of the sole plate. The present invention is advantageous because it extends the distance between the articulation axis and the pivot point of the floor tool. Increasing the distance between the articulation axis and the pivot point by extending at least a portion of the floor engaging surface of the sole plate beyond the back sole plate engaging edge of the head has been found to make it much harder to pivot the floor tool during normal use thus helping to reduce skipping. 
     In a preferred embodiment the portion extends beyond the back sole plate engaging edge of the head along the entire or substantially the entire length of the soleplate. In this embodiment the portion is essentially an extension of the floor engaging surface  36  of the sole plate, such that the rearward floor contacting edge is located beyond the back sole plate engaging edge of the head. In this embodiment the pivot point is the rearward floor contacting edge of the sole plate. The portion may be of any suitable length or shape as long as it extends beyond the back sole plate engaging edge of the head to increase the length of the floor engaging surface and thus increase the distance between the articulation axis and the pivot pint. 
     Alternatively, the floor tool may comprise a plurality of portions. Again the portions may be of any suitable shape as long as at least one portion extends beyond the back sole plate engaging edge of the head to increase the length of at least a portion of the floor engaging surface and thus increase the distance between the articulation axis and the pivot pint. As an example, in cross section, one or more portions may be tear shaped, square, rectangular or triangular in shape. The floor engaging surface of the portion(s) may also be of any suitable shape for example square, rectangular or triangular. 
     In a preferred embodiment the floor tool may comprise a single portion which extends beyond the back sole plate engaging edge of the head at a location spaced from side edges of the sole plate. For example the portion may be located centrally or substantially centrally. In a preferred embodiment the portion may be located in line with the outlet of the floor tool. 
     The portion may extend at least 10 mm, or 12 mm, or 14 mm, or 16 mm, or 18 mm, or 20 mm, or 22 mm, or 24 mm, or 26 mm beyond the back sole plate engaging edge of the head and/or beyond the rearward floor contacting edge of the sole plate. It is desirable that the portion is as long as possible. 
     In a preferred embodiment the portion or a pivot point of the portion may extend from 30 mm, or 35 mm, or 40 mm, or 45 mm, or 50 mm, to 55 mm or 60 mm, or 65 mm, or 70 mm, or 100 mm from the articulation axis. In a particularly preferred embodiment the portion may extend from 50 mm to 55 mm, for example 53.4 mm from the articulation axis 
     The portion may be of any suitable width and depth. The width may be from 2 mm, or 10 mm, or 15 mm, or 20 mm, or 25 mm, or 30 mm, or 35 mm, or 40 mm, or 45 mm, to 50 mm, or 55 mm, or 60 mm, or 65 mm, or 70 mm, or 75, or 80 mm or the entire length of the sole plate. 
     The depth may be from 1 mm, or 2 mm, or 3 mm, or 4 mm, or 5 mm deep. In a particular embodiment the portion may be the same depth as the remainder of the sole plate. 
     The sole plate may further comprise a front lip which may extend from at least a part of the forward floor contacting edge of the soleplate. Ideally a front lip may extend from the entire or substantially the entire length of the forward floor contacting edge of the soleplate. In a preferred embodiment the front lip may curve upwardly, for example upwardly and away from the forward floor contacting edge of the soleplate. 
     The sole plate may also further comprise a rear lip which may extend from at least a part of the rearward floor contacting edge of the soleplate. Ideally a rear lip may extend from the entire or substantially the entire length of the soleplate. In some embodiments the rear lip may be split into separate sections because the portion or portions may split the rearward floor contacting edge. 
     In a preferred embodiment the rear lip or one or more sections of the rear lip may curve upwardly, for example upwardly and away from the rear floor contacting edge of the soleplate. It is also possible that at least a section of the rear lip may be larger than at least another section of the rear lip and/or a section of the front lip. For example, in an embodiment where the portion is an extension of the floor engaging surface of the sole plate i.e. where the floor engaging surface of the sole plate extends beyond the back sole plate engaging edge of the head, a relatively larger rear lip may extend from the rearward floor contacting edge of the soleplate and a relatively smaller lip may extend from the forward floor contacting edge of the soleplate. Such lips may help to prevent the sole plate “digging in” to a carpet during use of the cleaning appliance. 
     In a particular embodiment the rear lip along a part of its length or all of its length may be associated with the portion, for example the pivot point of the portion may be connected to the lip in some manner. Thus the portion may be in the form of a loop or a solid shape such that at least a part of the portion and at least a part of the rear lip, for example the pivot point and the rear edge of the rear lip may be connected. 
     According to a second aspect of the present invention there is provided a surface treating appliance including a floor tool as described above. In a preferred embodiment the surface treating appliance may be in the form of a cyclonic vacuum cleaner. The surface treating appliance may be a handheld vacuum cleaner. Other aspects of the second aspect may be as described in relation to the first aspect. 
     The term “surface treating appliance” is intended to have a broad meaning, and includes a wide range of machines having a floor tool for travelling over a surface to clean or treat the surface in some manner. It includes, inter alia, machines which apply suction to the surface so as to draw material from it, such as vacuum cleaners (dry, wet and wet/dry), as well as machines which apply material to the surface, such as polishing/waxing machines and shampooing machines. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the invention will now be described with reference to the accompanying drawings, in which: 
         FIG. 1  shows a view of a floor tool according to the present invention attached to a handheld vacuum cleaner, 
         FIG. 2  is a front perspective view of a first embodiment of a floor tool according to the present invention, 
         FIG. 3  is a rear perspective view of the floor tool shown in  FIG. 2 , 
         FIG. 4  is a rear perspective view of the floor tool shown in  FIGS. 2 and 3 , 
         FIGS. 5 and 6  are side views of the floor tool shown in  FIGS. 2 to 4 , 
         FIG. 7  is an underside view of the floor tool shown in  FIGS. 2 to 6 , 
         FIG. 8  is a front perspective view of a second embodiment of a floor tool according to the present invention, 
         FIG. 9  is a rear perspective view of the floor tool shown in  FIG. 8 , 
         FIG. 10  is a rear perspective view of the floor tool shown in  FIGS. 8 and 9 , 
         FIG. 11  is a front perspective view of a third embodiment of a floor tool according to the present invention, 
         FIG. 12  is a rear perspective view of the floor tool shown in  FIG. 11 , and 
         FIG. 13  is a rear perspective view of the floor tool shown in  FIGS. 10 and 11 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a hand-held vacuum cleaner  100 . The hand-held vacuum cleaner  100  comprises a suction conduit  2  having a suction opening  4  in an attached floor tool  1 . The vacuum cleaner  100  also includes cyclonic separating apparatus  6  for separating dirt and dust from an airflow drawn in through the suction opening  4 . The cyclonic separating apparatus  6  is in communication with the suction conduit  2  and the suction opening  4 . The cyclonic separating apparatus  6  comprises an upstream cyclone  8  and a plurality of downstream cyclones  10 . 
     The vacuum cleaner  100  further includes a motor housing  12  and a removable casing  14  having a plurality of exhaust vents  16  formed therein. An air flow path extends from the suction opening  4 , through the suction conduit  2 , the cyclonic separating apparatus  6  and the motor housing  12  to the exhaust vents  16 . A handgrip  18  is located below the motor housing  12  for manipulating the hand-held vacuum cleaner  100  when in use. The handgrip  18  is arranged so that the cyclonic separating apparatus  6  is located between the handgrip  18  and the suction opening  4 . The handgrip  18  includes a trigger switch  20  which is positioned on the side of the handgrip  18  closest to the suction opening  4  such that the trigger switch  20  can be manipulated by a user&#39;s index finger. A power source  22  in the form of a lithium ion battery pack is connected to the handgrip  18  through a mounting portion  24 . 
     When operating, an airflow generator (not shown) draws a flow of dirt- and dust-laden air into the suction opening  4  of the floor tool  1 , through the suction conduit  2  and into the cyclonic separating apparatus  6 . The cleaned air exits the cyclonic separating apparatus  6  and passes sequentially through a pre-motor filter if present and the airflow generator before being exhausted through the exhaust vents  16 . 
     In order to clean a floor, the user grips the handle  18  and maneuvers the floor tool  1  across the floor surface. 
       FIGS. 2 to 7  show a first embodiment of the floor tool  1  in greater detail. It can be seen that the floor tool  1  includes a head  25 , a sole plate  26  and a connecting arm  28 . The connecting arm  28  is rigidly attached to the head  25 , although it is possible that it could be pivotally connected to the head  25  if desired. The sole plate  26  is pivotally connected to the head  25  about an articulation axis A (shown in  FIGS. 3 and 6 ). 
     The head  25  includes a barrel shaped body  29  in which a brush bar  30  is located. The brush bar  30  is rotatable about the same axis A that the sole plate  26  is rotatable about. The brush bar  30  may be of any suitable construction and may be either motor or turbine driven. 
     The soleplate  26  faces a floor surface in use and includes a suction opening  4 . The suction opening  4  is in the form of a plurality of apertures  34  defined by a floor engaging surface  36  of the sole plate  26 . It can also be seen that the sole plate  26  further comprises upstanding front and rear walls (only the front wall  38  can be seen) which correspond in shape to the inner surface of the barrel shaped body  29  of the head  25 . These walls  38  ensure that as the head  25  rotates about the articulation axis A, a substantially airtight pathway is always provided between the suction opening  4  and the outlet  42  of the connecting arm  28 . 
     The head  25  further comprises a front sole plate engaging edge  31  and a back sole plate engaging edge  33 . The front sole plate engaging edge  31  comes into contact with the sole plate  26  when the head  25  is in its forward position. The back sole plate engaging edge  33  comes into contact with the sole plate  26  when the head  25  is in the rearward position. This rearward position can be seen in  FIGS. 2 to 6 . 
     The floor engaging surface  36  of the sole plate  26  has forward and rearward floor contacting edges  44 ,  46 . The sole plate  26  also further comprises and a front and rear lip  48 ,  50 . The front and rear lips  48 ,  50  have front and rear edges  52 ,  54  respectively. It can be seen that the front lip  48  curves upwardly from the forward floor contacting edge  44  of the soleplate  26  and the rear lip  50  curves upwardly from the rearward floor contacting edge  46  of the sole plate  26 . 
     In  FIGS. 3 and 4  a portion  56  can be seen to extend from the rearward floor contacting edge  46  of the sole plate  26  beyond the back sole plate engaging edge  33  of the head  25  when the head  25  is in the rearward position. This extends the distance between the articulation axis A and the pivot point  47  which is located at the back edge of the portion  56 . Increasing this distance makes it much harder to pivot the whole floor tool  1  during normal use thus helping to reduce skipping. Without the portion  56  the floor tool  1  would pivot about the rearward floor contacting edge  46  of the sole plate  26  which would occur much more readily during normal use of the vacuum cleaner  100 . 
     In the embodiment shown in  FIGS. 2 to 7  it can be seen that there is a single portion  56 . It is of course possible to have a plurality of such portions  56 . Such a portion  56  or portions may be located at any suitable position along the length of the rearward floor contacting edge  46  of the sole plate  26 . In  FIGS. 3 to 6  it can be seen that the portion  56  curves upwardly to form a loop  58 . It can be seen in  FIGS. 3 and 4  that the loop  58  connects a portion of the rear edge  54  of the rear lip  50  with the pivot point  47  at the rear edge of the portion  56 . 
     The shape of the portion  56  is not important, the important feature is that the distance between the pivot point  47  of the floor tool  1  and the axis A is as large as possible. The loop  58  could therefore be solid and the edges could be angled rather than curved as long as there is a flat surface which lies in the same plane as the floor engaging surface  36  of the sole plate  26  and which extends rearwardly beyond the back sole plate engaging edge  33  of the head  25  when the head  25  is in the rearward position. For example the portion  56  could be planar, cuboidal, pyramidal or any other suitable shape. 
     In the second embodiment shown in  FIGS. 8 to 10  there is a single portion  56 . In this embodiment the portion  56  has a free end. In other words the portion  56  is not connected to a portion of the rear edge  54  of the rear lip  50  as in the first embodiment. In this second embodiment the portion  56  extends rearwardly in the same plane as the floor contacting surface  36  of the sole plate  26  for a distance beyond the back sole plate engaging edge  33  of the head  25  when the head  25  is in the rearward position. The portion  56  then curves upwardly. In the embodiment shown the curved portion  49  on portion  56  is larger than the rear lip  50  which extends from the rearward floor contacting edge  46  of the sole plate  26  on either side of the portion  56 . Again the exact shape of the portion  56  is not important, the important feature is that the distance between the pivot point  47  of the floor tool  1  and the axis A is as large as possible. 
     In the third embodiment shown in  FIGS. 11 to 13  the portion  56  is an extension of the floor engaging surface  36  of the soleplate  26  along its entire length. Again this portion extends rearwardly in the same plane as the floor contacting surface  36  of the sole plate  26  for a distance beyond the back sole plate engaging edge  33  of the head  25  and then a rear lip  50  curves upwardly. 
     In  FIGS. 11 to 13  it can be seen that the rear lip  50  is larger than the front lip  48 . In an alternative embodiment the rear lip  50  may be the same size or smaller than the front lip  48 . In another alternative embodiment there may only be one lip  48 ,  50  or no lips. Again the exact shape of the portion  56  is not important, the important feature is that the distance between the pivot point  47  of the floor tool  1  and the axis A is as large as possible. In this embodiment the pivot point  47  is also the rearward floor contacting edge  46  of the sole plate  26 .