Patent Publication Number: US-9420927-B2

Title: Vacuum cleaner tool

Description:
REFERENCE TO RELATED APPLICATION 
     This application claims priority of United Kingdom Application No. 1402281.8, filed Feb. 10, 2014, the entire contents of which are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to a tool for a vacuum cleaner. 
     BACKGROUND OF THE INVENTION 
       FIGS. 1 and 2  illustrate a known type of vacuum cleaner tool  1 . The tool  1  comprises a nozzle  2  having an elongate suction opening  3 , and a strip of the bristles  4  that protrude through the suction opening  3 . The tool  1  is intended to be swept from side-to-side in directions normal to the suction opening  3 . As the tool  1  is swept forwards, the bristles  4  bend backwards and contact the trailing edge of the nozzle  2 . The suction opening  3  is therefore located in front of the bristles  4  irrespective of the direction of travel. 
     A problem with the tool  1  is that the bristles  4  must be relatively stiff in order to avoid the bristles  4  being drawn up into the nozzle  2 . The disadvantage of stiff bristles is that they are more likely to mark the cleaning surface. 
     SUMMARY OF THE INVENTION 
     The present invention provides a tool for a vacuum cleaner, the tool comprising a nozzle and a bristle assembly, wherein an elongate suction opening is provided in a base of the nozzle, the bristle assembly is mounted within the nozzle and comprises a carrier to which a strip of bristles is attached, the carrier pivots or flexes relative to the nozzle and comprises a pair of wings located on opposite sides of the bristles, and the bristles protrude beyond the carrier by a distance no greater than the width of each wing. 
     The bristles that protrude beyond the carrier therefore have a length that is smaller than the width of the wings. As a result, is not possible for the bristles to be drawn up into the suction opening. In particular, the wings prevent the bristles from being drawn up into the suction opening. As a result, relatively fine and soft bristles may be used. By attaching the bristles to a carrier that pivots or flexes, the bristles are required to bend through a smaller angle. The bristles are therefore subjected to smaller stresses, thus improving the longevity of the bristles. Additionally, the bristles are better able to retain their shape. 
     The suction opening may be delimited along its length by a first edge and a second edge, and the wings may extend outwardly from the bristles towards the first edge and the second edge. The carrier then pivots or flexes such that one of the wings contacts the first edge as the tool is swept forwards and the other of the wings contacts the second edge as the tool is swept backwards over the cleaning surface. By contacting one of the two edges of the nozzle as the tool is swept forwards and backwards, the carrier proves an effective seal against the nozzle. Consequently, the pickup performance of the tool is not compromised by the provision of the carrier. 
     The base may be curved at a front and at a rear of the nozzle. This then has the advantage that, as the tool is swept forwards and backwards, the tool rocks smoothly over the cleaning surface. 
     A further suction opening may be provided in a front of the nozzle. As a result, the tool is better able to pick up dirt along edges and at corners of the cleaning surface. The bristles may extend through the further opening. This then has two advantages. First, the length and thus the coverage of the strip of bristles are increased. Second, the bristles are able to penetrate edges and corners of the cleaning surface and thus agitate trapped dirt. 
     Each wing may include a winglet that extends upwardly from a tip of the wing. The winglet helps to straighten the airflow drawn through the suction opening and thus reduce turbulence. As a result, less noise is generated by the airflow as it is drawn through the tool. 
     A protective pad may be secured to the base of the nozzle so as to surround at least part of the suction opening. Additionally or alternatively, a protective pad may be secured to each wing. The protective pad is softer and/or has a lower coefficient of friction than that of the nozzle or carrier. This then has the advantage that the tool is less likely to mark the cleaning surface and/or the tool may be swept more smoothly over the cleaning surface. 
     The bristles may be formed of carbon fibre. A strip of bristles has the advantage that no streaks of dirt are left behind as the tool is swept over the cleaning surface. Carbon fibre has at least two advantages. First, carbon fibre allows for relatively soft and fine bristles to be used, which help reduce marking of the cleaning surface. Second, carbon fibre has good anti-static properties, which means that the bristles can be swept over the cleaning surface without charging the surface. In contrast, nylon bristles tend to charge the cleaning surface and the resulting static then acts to attract dirt. 
     The present invention also provides a tool for a vacuum cleaner, the tool comprising a nozzle and a bristle assembly, wherein an elongate suction opening is provided in a base of the nozzle, the suction opening is delimited along its length by a first edge and a second edge, the bristle assembly is mounted within the nozzle and comprises a carrier to which a strip of bristles is attached, the carrier comprises a pair of wings located on opposite sides of the bristles, the wings extend outwardly from the bristles towards the first edge and the second edge, and the carrier pivots or flexes relative to the nozzle such that one of the wings contacts the first edge as the tool is swept forwards and the other of the wings contacts the second edge as the tool is swept backwards over the cleaning surface. 
     By attaching the bristles to a carrier that pivots or flexes, the bristles are required to bend through a smaller angle. The bristles are therefore subjected to smaller stresses, thus improving the longevity of the bristles. Additionally, the bristles are better able to retain their shape. The wings may also help to prevent the bristles from being drawn up into the suction opening. By contacting one of the two edges of the nozzle as the tool is swept forwards and backwards, the carrier proves an effective seal against the nozzle. Consequently, the pickup performance of the tool is not compromised by the provision of the carrier. 
     The present invention further provides a tool for a vacuum cleaner, the tool comprising a nozzle and a bristle assembly, wherein an elongate suction opening is provided in a base of the nozzle, the suction opening is delimited along its length by a first edge and a second edge, the bristle assembly is mounted within the nozzle and comprises a carrier to which a strip of bristles is attached, the carrier comprises a pair of wings located on opposite sides of the bristles, the wings extend outwardly from the bristles towards the first edge and the second edge, the carrier pivots or flexes relative to the nozzle such that one of the wings contacts the first edge as the tool is swept forwards and the other of the wings contacts the second edge as the tool is swept backwards over the cleaning surface, the bristles protrude beyond the carrier by a distance no greater than the width of each wing, and the bristles are formed of carbon fibre. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order that the present invention may be more readily understood, embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: 
         FIG. 1  is a side view of a known type of vacuum cleaner tool; 
         FIG. 2  is a sectional view through the tool of  FIG. 1 , the section being taken in the plane A-A; 
         FIG. 3  is a perspective view of a first vacuum cleaner tool; 
         FIG. 4  is a side view of the tool of  FIG. 3 ; 
         FIG. 5  is an underside view of the tool of  FIG. 3 ; 
         FIG. 6  is a sectional view through the tool of  FIG. 3 , the section being taken in the plane C-C indicated in  FIG. 5 ; 
         FIG. 7  is a sectional view through the tool of  FIG. 3 , the section being taken in the plane B-B indicated in  FIG. 4 ; 
         FIG. 8  is a sectional view through the tool of  FIG. 3  as the tool is swept across a surface, the section being taken in the plane B-B; 
         FIG. 9  is a perspective view of a second vacuum cleaner tool; 
         FIG. 10  is a side view of the tool of  FIG. 9 ; 
         FIG. 11  is an underside view of the tool of  FIG. 9 ; 
         FIG. 12  is a sectional view through the tool of  FIG. 9 , the section being taken in the plane E-E indicated in  FIG. 11 ; 
         FIG. 13  is a sectional view through the tool of  FIG. 9 , the section being taken in the plane D-D indicated in  FIG. 10 ; 
         FIG. 14  is a sectional view through the tool of  FIG. 9  as the tool is swept across a surface, the section being taken in the plane D-D; 
         FIG. 15  is a perspective view of a third vacuum cleaner tool; 
         FIG. 16  is a side view of the tool of  FIG. 15 ; 
         FIG. 17  is an underside view of the tool of  FIG. 15 ; 
         FIG. 18  is a sectional view through the tool of  FIG. 15 , the section being taken in the plane G-G indicated in  FIG. 17 ; 
         FIG. 19  is an exploded view of the tool of  FIG. 15 ; 
         FIG. 20  is a sectional view through the tool of  FIG. 15 , the section being taken in the plane F-F indicated in  FIG. 16 ; and 
         FIG. 21  is a sectional view through the tool of  FIG. 15  as the tool is swept across a surface, the section being taken in the plane F-F. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The vacuum cleaner tool  10  of  FIGS. 3 to 8  comprises a nozzle  11 , a connecting duct  12 , and a bristle assembly  13 . 
     The nozzle  11  is a relatively narrow structure, with the width of the nozzle  11  being much smaller than the length of the nozzle  11 . The height of the nozzle  11  tapers (i.e. decreases gradually) from the rear  16  to the front  15  of the nozzle  11 , the advantages of which are explained below. The nozzle  11  comprises a suction opening  20  that opens up into an internal cavity  21  within the nozzle  11 . The suction opening  20  is located in the base of the nozzle  11  and extends centrally from the front  15  to the rear  16  of the nozzle  11 . The suction opening  20  is delimited along its length by two edges  22 , 23  of the nozzle  11 . Each edge  22 , 23  is raised relative to the lower ends  17 , 18  of the front  15  and the rear  16  of the nozzle  11 . Consequently, when the base of the nozzle  11  is brought into contact with a cleaning surface  40 , a gap  25  is created between each of the edges  22 , 23  and the cleaning surface  40 . Again, the advantages of this are explained below. 
     The connecting duct  12  is attached to the rear  16  of the nozzle  11  and is in fluid communication with the cavity  21  and thus the suction opening  20  of the nozzle  11 . The connecting duct  12  is intended to be attached to a hose, wand or the like of a vacuum cleaner (not shown). During use, the vacuum cleaner generates suction at the connecting duct  12 , causing air to be drawn in through the suction opening  20 . 
     The bristle assembly  13  is generally planar in shape and comprises a carrier  30  to which a strip of bristles  31  and a spine  32  are attached. 
     The carrier  30  is formed of a flexible material such as rubber. The bottom of the carrier  30  rises relative to the top in a direction from the rear to the front of the carrier  30 . As a result, the height of the carrier  30  tapers (i.e. decreases gradually) from the rear  37  to the front  36  of the carrier  30 . 
     The bristles  31  are formed of carbon fibre and extend beyond the bottom of the carrier  30 . The bristles  31  are attached to the carrier  30  by moulding the carrier  30  over the upper ends of the bristles  31 . However, the bristles  31  could conceivably be attached to the carrier  30  by other means. The lengths of the bristles  31  taper (i.e. decrease gradually) from the front to the rear of the carrier  30 . Consequently, the lengths of the bristles  31  at the rear of the carrier  30  are shorter than those at the front. 
     The spine  32  is formed of a rigid material, such as hard plastic, and is attached along the top of the carrier  30 . The spine  32  provides structural support for the carrier  30 , as well as providing means for attaching the bristle assembly  13  to the nozzle  11 . 
     The bristle assembly  13  is mounted within the cavity  21  of the nozzle  11  such that the carrier  30  and the bristles  31  protrude through the suction opening  20 . More specifically, the front  15  and the rear  16  of the nozzle  11  each include a recess into which the ends of the spine  32  are secured. The bristle assembly  13  is mounted within the cavity  21  such that the taller part of the carrier  30  and the shorter bristles  31  are located at the rear of the suction opening  20 . 
     The tool  10  is intended to be swept across a cleaning surface  40  in directions normal to the suction opening  20 . As the tool  10  is swept forwards, the bristle assembly  13  flexes backwards. The suction opening  20  is then located wholly in front of the bristles  31 . The bristles  31  create a partial seal with the cleaning surface  40 , which then improves the suction that is generated in front of the bristles  31 . As the tool  10  is swept over the cleaning surface  40 , the suction generated in front of the bristles  31  causes dirt to be drawn into the cavity  21  of the nozzle  11  via the suction opening  20 . Thereafter, the dirt is carried to the vacuum cleaner via the connecting duct  12 . The bristles  31  act to pick up much of the dirt that is not drawn into the nozzle  11 . The bristles  31  then hold on to the dirt until such time as the dirt is drawn into the nozzle  11 , e.g. when the tool  10  is lifted from the cleaning surface  40  or when the direction of travel of the tool  10  is reversed. 
     As the tool  10  is swept over the cleaning surface  40 , the front  15  and the rear  16  of the nozzle  11  make contact with the cleaning surface  40 . Of the two edges  22 , 23  that delimit the length of the suction opening  20 , one defines a leading edge  22  of the nozzle  11  and the other defines a trailing edge  23 . Since the two edges  22 , 23  are raised relative to the front  15  and rear  16  of the nozzle  11 , a gap  25  is created between the leading edge  22  of the nozzle  11  and the cleaning surface  40 . This gap  25  ensures that, as the tool  10  is swept over the cleaning surface  40 , dirt is able to pass under the leading edge  22 . As a result, the tool  10  does not push the dirt over the cleaning surface  40 . During use, a user will typically tilt the tool  10  in the direction of travel such that an acute angle is formed between the nozzle  11  and the cleaning surface  40 , as shown in  FIG. 8 . As a consequence of tilting the nozzle  11 , the leading edge  22  is brought closer to the cleaning surface  40 . Nevertheless, the gap  25  between the leading edge  22  and the cleaning surface  40  is maintained. As the tool  10  is tilted further forwards, the gap  25  between the leading edge  22  and the cleaning surface  40  decreases. Eventually, with sufficient tilting, the leading edge  22  may contact the cleaning surface  40 . At this stage, the nozzle  11  would then start to push dirt along the cleaning surface  40 . This problem may be mitigated by further raising the edges  22 , 23  of the nozzle  11  such that a larger nominal gap  25  is created between the leading edge  22  and the cleaning surface  40 . However, a larger gap  25  has the disadvantage that more air is likely to be pulled in from the region above the cleaning surface  40  rather than at the cleaning surface  40  and thus pickup performance is adversely affected. The edges  22 , 23  are therefore raised by an amount which seeks to balance the need to maintain a relatively small gap  25  with the need to maintain a gap  25  over the range of angles through which the tool  10  is likely to be used. 
     The spine  32  provides structural support along the top  35  of the carrier  30 . This then helps prevent the carrier  30  from flexing upwards during use of the tool  10 , e.g. as a result of the suction generated within the nozzle  11  or when the tool  10  is swept over an uneven surface. 
     Employing a strip of bristles  31  has the advantage that streaks of dirt are not left behind as the tool  10  is swept over the cleaning surface  40 . The choice of carbon fibre has at least two advantages. First, carbon fibre enables relatively soft and fine bristles  31  to be used, which then helps to reduce marking of the cleaning surface  40 . Second, carbon fibre has good anti-static properties. Consequently, as the bristles  31  are swept over the cleaning surface  40 , the bristles  31  do not charge the cleaning surface  40 . In contrast, nylon bristles tend to charge the cleaning surface, and the resulting static then acts to attract dirt to the cleaning surface. 
     Although advantageous, employing soft, fine bristles is not without its difficulties. In particular, if such bristles were employed with the tool  1  of  FIGS. 1 and 2 , the suction generated at the suction opening  3  would most likely to draw the bristles  4  into the nozzle  2 . The tool  10  of  FIGS. 3 to 8  has several features that help to prevent this from happening. 
     First, the lengths of the bristles  31  taper from the front to the rear of the suction opening  20 . Consequently, the bristles  31  at the rear of the suction opening  20  are shorter than those at the front. Longer bristles have the advantage that they are more flexible and thus less likely to mark the cleaning surface  40 . Additionally, longer bristles are better able to penetrate awkward surfaces and thus improve pickup performance. It would therefore be advantageous to employ longer bristles along the full length of the suction opening  20 . However, if longer bristles are employed along the full length of the suction opening  20  then the bristles  31  at the rear of the suction opening  20  may be drawn up into the nozzle  10 . This is because the suction generated at the suction opening  20  is generally greatest at the rear of the suction opening  20  due to the location of the connecting duct  12 . By employing shorter bristles  31  at the rear of the suction opening  20 , the bristles  31  are stiffer and thus less likely to be drawn up into the nozzle  11 . Conversely, by employing longer bristles  31  at the front of the suction opening  20 , the bristles  31  are better able to penetrate awkward surfaces and thus improve pickup. The suction at the suction opening  20  typically decreases along the length of the suction opening  20 . Accordingly, by having bristles  31  that taper in length along the length of the suction opening  20 , relatively good pickup may be achieved whilst ensuring that the bristles  31  are of sufficient length to prevent them being drawn into the nozzle  11 . 
     Second, the bristles  31  are attached to a carrier  30  which provides support for the bristles  31 . Additionally, the carrier  30  protrudes beyond the suction opening  20 . The suction experienced by the bristle assembly  13  decreases markedly just beyond the suction opening  20  owing to the sudden expansion in available volume. Since the carrier  30  protrudes beyond the suction opening  20 , the suction experienced by the bristles  31  is much reduced and thus relatively soft and fine bristles may be used. In contrast, with the tool  1  of  FIGS. 1 and 2 , the bristles  4  are unsupported and extend through the suction opening  3  and into the cavity of the nozzle  2 . As a result, the bristles  4  are subjected to higher levels of suction and thus stiffer bristles  4  must be used in order to ensure that the bristles  4  are not drawn into the nozzle  11 . The carrier  30  is not of uniform height but is instead taller at the rear of the suction opening  20 . As noted in the preceding paragraph, the suction generated at the suction opening  20  is generally greatest at the rear of the suction opening  20 . By employing a carrier  30  that is taller at the rear of the suction opening  20 , the carrier  30  provides additional rigidity and support to the bristles  31  where it is needed most. 
     Third, the height of the nozzle  11  tapers from the rear  16  to the front  15  of the nozzle  11 . If the nozzle  11  were of uniform height, the suction generated at the suction opening  20  would be much greater at the rear than at the front of the suction opening  20 . This follows since the connecting duct  12  is located at the rear of the nozzle  11 . The increased suction at the rear of the suction opening  20  might then cause the bristles  31  to be drawn into the nozzle  11 . Additionally, the suction and thus the pickup performance at the front of the suction opening  20  would be poorer. By tapering the height of the nozzle  11 , the volume of the cavity  21  within the nozzle  11  also tapers from the rear  16  to the front  15  of the nozzle  11 . A larger open volume is therefore created within the nozzle  11  at the rear of the suction opening  20 , and a smaller open volume is created at the front of the suction opening  20 . The suction is therefore better balanced along the length of the suction opening  20 . As result, softer, finer bristles may be used at the rear of the suction opening  20 , and the pickup performance at the front of the suction opening  20  may be improved. 
     The carrier  30 , being formed of a flexible material, flexes relative to the nozzle  11  as the tool  10  is swept over the cleaning surface  40 . As a result, the bristles  31  are required to bend through a smaller angle. The bristles  31  are therefore subjected to smaller stresses, thus improving the longevity of the bristles  31 . Additionally, the bristles  31  are better able to retain their shape. In contrast, the bristles  4  of the tool  1  of  FIGS. 1 and 2  are subjected to higher bending stresses. Rather than employing a flexible carrier  30 , the bristle assembly  13  could conceivably comprise a carrier formed of a rigid material. The bristle assembly  13  might then be pivotally attached to the nozzle  11 , and a spring mechanism could be used to ensure that the carrier returns to a central position when the tool  10  is lifted from the cleaning surface  40 . Nevertheless, a flexible carrier  30  has the advantage that the resilience is provided by the carrier  30  itself. As a result, a spring-loaded pivot can be avoided, thereby reducing the cost and/or simplifying the assembly of the tool  10 . 
     The carrier  30  protrudes beyond the suction opening  20  by an amount that ensures that, when the bristle assembly  13  is swept backwards (e.g. during a forward sweep of the tool  10 ), the carrier  30  contacts the trailing edge  23 . More specifically, the carrier  30  contacts the trailing edge  23  along the full length of the carrier  30 . By contacting the trailing edge  23 , the carrier  30  provides a better seal against the trailing edge  23  of the nozzle  11  than would otherwise be possible with the bristles  31 . Consequently, less air is pulled in through the trailing side of the tool  10  and thus more suction is generated in front of the bristles  31 , thereby improving pickup. 
       FIGS. 9 to 14  illustrate an alternative vacuum cleaner tool  50  that is similar in many respects to that described above and illustrated in  FIGS. 3 to 8 . In particular, the tool  50  comprises a nozzle  51 , a connecting duct  52 , and a bristle assembly  53 . 
     The nozzle  51  is somewhat different in shape to that of  FIGS. 3 to 8 . The nozzle  11  of  FIGS. 3 to 8  has a cross-sectional shape that is generally rectangular. In contrast, the cross-sectional shape of the nozzle  51  of  FIGS. 9 to 14  is generally triangular. Accordingly, the shape of the nozzle  51  may be regarded as an elongate prism. The width of the nozzle  11  of  FIGS. 3 to 8  is constant along the length of the nozzle  11 , whilst the height of the nozzle  11  tapers from the rear  16  to the front  15  of the nozzle  11 . In contrast, the height of the nozzle  51  of  FIGS. 9 to 14  is constant, and the width of the nozzle  51  tapers (i.e. decreases gradually) from the rear  56  to the front  55  of the nozzle  51 . 
     The nozzle  51 , like that of  FIGS. 3 to 8 , comprises a suction opening  60  that opens up into an internal cavity  61  within the nozzle  51 . The suction opening  60  is again located in the base of the nozzle  61  and extends centrally from the front  55  to the rear  56  of the nozzle  51 . In contrast to the nozzle  11  of  FIGS. 3 to 8 , the suction opening  60  is not of uniform width. Instead, the width of the suction opening  60  tapers (i.e. decreases gradually) from the rear to the front of the suction opening  60 , the benefits of which are explained below. The suction opening  60  is again delimited along its length by two edges  62 , 63  of the nozzle  51  that are raised relative to the front  55  and the rear  56  of the nozzle  51 . Consequently, when the base of the nozzle  51  is brought into contact with the cleaning surface  40 , a gap  65  is created between the leading edge  62  and the cleaning surface  40 . The lower ends  57 , 58  of the front  55  and rear  56  of the nozzle  51  are curved. Furthermore, the lower ends  57 , 58  are each covered with a protective pad  68  formed of a tufted fabric, the benefits of which are explained below. 
     The connecting duct  52  is essentially unchanged from that of  FIGS. 3 to 8 . In particular, the connecting duct  52  is attached to the rear  56  of the nozzle  51  and is intended to be attached to a hose, wand or the like of a vacuum cleaner (again, not shown). 
     The bristle assembly  53  is again generally planar in shape and comprises a carrier  70  to which a strip of bristles  71  is attached. 
     The carrier  70  is formed of a flexible material, such as rubber, and the bottom of the carrier  70  rises relative to the top in a direction from the rear to the front of the carrier  70 . As a result, the height of the carrier  70  again tapers from the rear to the front of the carrier  70 . In contrast to the carrier  30  of  FIGS. 3 to 8 , the carrier  70  comprises a pair of through-holes  78 , 79  located towards the rear of the carrier  70 . The through-holes  78 , 79  have different sizes, with the through-hole  78  closest to the rear of the carrier  70  being larger. 
     The bristles  71  are again formed of carbon fibre and extend beyond the bottom of the carrier  70 . However, unlike the bristles  31  of  FIGS. 3 to 8 , the lengths of the bristles  71  do not taper. Instead, the lengths of the bristles  71  are constant from the rear to the front of the carrier  70 . 
     The bristle assembly  53  is mounted within the cavity  61  of the nozzle  51  such that the carrier  70  and the bristles  71  protrude through the suction opening  60 . In contrast, to the bristle assembly  13  of  FIGS. 3 to 8  which is attached to the front  15  and rear  16  of the nozzle  11 , the bristle assembly  71  of  FIGS. 9 to 14  is attached to the top  59  of the nozzle  51 . In particular, the top of the carrier  70  is secured (e.g. by means of an adhesive) within a groove  69  formed along the top  59  of the nozzle  51 . The bristle assembly  13  of  FIGS. 3 to 8  includes a spine  32  that provides structural support along the top  35  of the carrier  30 . Since the bristle assembly  53  of  FIGS. 9 to 14  is attached along the top  59  of the nozzle  51 , the spine may be omitted and the top  59  of the nozzle  51  may provide the necessary support. That being said, there may be advantages in employing a spine. For example, the bristle assembly  53  may comprise a spine that snaps into a groove in the top  59  of the nozzle  51 . This then has the potential advantage of simplifying the assembly of the tool  50 . In particular, the use of an adhesive to secure the bristle assembly  53  to the nozzle  51  may be avoided. 
     With the tool  10  of  FIGS. 3 to 8 , the bristle assembly  13  protrudes beyond the suction opening  20  by an amount that is constant along the length of the suction opening  20 . In contrast, with the tool  50  of  FIGS. 9 to 14 , the amount by which the bristle assembly  53  protrudes beyond the suction opening  60  tapers (i.e. decreases gradually) from the rear to the front of the suction opening  60 . Consequently, the amount by which the bristle assembly  53  protrudes beyond the suction opening  60  is greater at the rear of the suction opening  60  than at the front of the suction opening  60 . 
     The tool  50  of  FIGS. 9 to 14  is intended to be used in exactly the same way as that described above in connection with the tool  10  of  FIGS. 3 to 8 . In particular, the tool  50  is intended to be swept across the cleaning surface  40  in directions normal to the suction opening  60 . As the tool  50  is swept forwards, the bristle assembly  53  flexes backwards such that the suction opening  60  is located wholly in front of the bristles  71 . The bristle assembly  53  contacts the cleaning surface  40  and the trailing edge  63  of the nozzle  51  so as to create a seal behind the suction opening  60 . 
     As the tool  50  is swept over the cleaning surface  40 , the front  55  and the rear  56  of the nozzle  51  make contact with the cleaning surface  40 . Since the leading and trailing edges  62 , 63  of the nozzle  51  are raised relative to the front  55  and rear  56 , a gap  65  is again created between the leading edge  62  and the cleaning surface  40 , thus ensuring that dirt is free to pass under the leading edge  62 . 
     The angle formed between the tool  50  and the cleaning surface  40  typically changes as the tool  50  is swept across the cleaning surface  40 . For example, the user may start with the tool  50  at an acute angle relative to the cleaning surface  40 . As the tool  50  is swept across the cleaning surface  40 , the tool  50  gradually straightens, perhaps finishing at an obtuse angle. The lower ends  57 , 58  of the nozzle  51  that contact the cleaning surface  40  are curved. This then has the advantage that, as the angle of the tool  50  changes, the lower ends  57 , 58  of the nozzle  51  rock over the cleaning surface  40  so as to provide a smooth transition. Moreover, the lower ends  57 , 58  of the nozzle  51  are each covered with a protective pad  68 . This has two benefits. First, the pads  68  have a lower coefficient of friction than that of the nozzle  51  and thus the tool  60  may be swept over the cleaning surface  40  more smoothly and with less effort. Second, the pads  68  are softer than the nozzle  51  and thus the tool  60  is less likely to mark the cleaning surface  40 . In the present embodiment, the pads  68  are each formed of a tufted fabric. However, the pads  68  might equally be formed of a different material that is softer and has a lower coefficient of friction than that of the nozzle  51 . By way of example only, the pads  68  may be formed of a felted fabric, an elastomeric foam perhaps having a low-friction coating such as PTFE, or a strip of very short and fine bristles. 
     As with the tool  10  of  FIGS. 3 to 8 , the tool  50  of  FIGS. 9 to 14  has several features that help prevent the bristles  71  from being drawn into the nozzle  51 . 
     First, the bristles  71  are again attached to a carrier  70 , which provides support for the bristles  71 . As with the tool  10  of  FIGS. 3 to 8 , the connecting duct  52  is attached to the rear  56  of the nozzle  51  and thus the suction is generally greatest at the rear of the suction opening  60 . The carrier  70  is again taller at the rear of the suction opening  60 . As a result, the carrier  70  provides additional rigidity and support to the bristles  71  where it is needed most. The carrier  70  also protrudes beyond the suction opening  60 , and thus the suction experienced by the bristles  71  is much reduced. 
     Second, the width of the suction opening  60  tapers from the rear to the front of the suction opening  60 . If the width of the suction opening  60  were uniform, the suction at the rear of the suction opening  60  would be significantly higher than that at the front of the suction opening  60 . The higher level of suction at the rear may cause the bristles  71  to be drawn into the nozzle  51 . By employing a suction opening  60  that is wider at the rear and narrower at the front, the suction along the length of the suction opening  60  is better balanced. In particular, the suction at the rear of the suction opening  60  is reduced so as to prevent the bristles  71  being drawn into the nozzle  51 , whilst the suction at the front of the suction opening  60  is increased so as to improve pickup. 
     Third, the width of the nozzle  51  tapers from the rear  56  to the front  55  of the nozzle  51 . This has the same benefit as tapering the height of the nozzle  11  of  FIGS. 3 to 8 , namely that the volume of the cavity  61  within the nozzle  51  decreases from the rear  56  to the front  55  of the nozzle  51 . A larger open volume is therefore created within the nozzle  51  at the rear of the suction opening  60 , and a smaller open volume is created at the front of the suction opening  60 . The suction is therefore better balanced along the length of the suction opening  60 . As result, softer, finer bristles  71  may be used at the rear of the suction opening  60 , whilst the pickup performance at the front of the suction opening  60  may be improved. Tapering the width rather than the height of the nozzle  51  has the additional benefit that a relatively low profile may be achieved for the tool  50 . In particular, the height of the tool may be kept relatively low and the required change in the volume of the cavity  61  may be achieved through changes in the width of the nozzle  51 . As a result, the tool  51  may be used to clean under spaces of relatively low height. 
     As with the tool  10  of  FIGS. 3 to 8 , the carrier  70  protrudes beyond the suction opening  60  by an amount that ensures that, when the bristle assembly  53  is swept backwards (e.g. during a forward sweep of the tool  50 ), the carrier  70  contacts the trailing edge  63  of the nozzle  51 . As noted above, this then ensures that a better seal is formed between the bristle assembly  53  and the trailing edge  63  of the nozzle  51 . The width of the suction opening  60  tapers from the rear  56  to the front  55  of the nozzle  51 . Accordingly, in order that the carrier  70  contacts the trailing edge  63  along the full length of the carrier  70 , the amount by which the carrier  70  protrudes beyond the suction opening  60  also tapers from the rear to the front. The bristles  71 , however, do not taper but are instead of constant length. This then has the advantage that longer bristles may be employed at the rear of the suction opening  60 . Additionally, bristles of constant length ensure that, when the bristle assembly  53  is swept backwards and the carrier  70  contacts the trailing edge  63 , the bristles  71  extend beyond the trailing edge  63  by an amount that is constant along the length of the trailing edge  63 . This then has the benefit of providing more even pickup along the length of the nozzle  51 . Since the height of the carrier  70  tapers but the lengths of the bristles  71  are constant, the bristle assembly  53  protrudes beyond the suction opening  60  by an amount that tapers from the rear to the front of the suction opening  60 . This is in contrast to the tool  10  of  FIGS. 3 to 8 , in which the bristle assembly  13  protrudes by the same amount along the length of the suction opening  20 . 
     With the tool  10  of  FIGS. 3 to 8 , a gap is created directly above the bristle assembly  13 , i.e. between the spine  32  and the top  19  of the nozzle  11 . This is perhaps best seen in  FIGS. 6 to 8 . Conceivably, fluff and other dirt drawn into the nozzle  11  may become trapped within this gap. With the tool  50  of  FIGS. 9 to 14 , on the other hand, the bristle assembly  53  is attached to the top  59  of the nozzle  51 . Consequently, fluff and other dirt are prevented from becoming trapped between the bristle assembly  53  and the top  59  of the nozzle  51 . 
     As the tool  51  is swept forwards over the cleaning surface  40 , the bristle assembly  53  is swept backwards and contacts the trailing edge  63  of the nozzle  51 . A seal is then created between the bristle assembly  53  and the trailing edge  63 . The suction generated within the cavity  61  creates a partial vacuum on the trailing side of the bristle assembly  53 . Since the suction opening  60  is typically open to ambient, the pressure on the leading side of the bristle assembly  53  is generally higher. Without the through-holes  78 , 79  in the carrier  70 , the difference in pressure on the two sides of the bristle assembly  53  may be sufficiently large that the bristle assembly  53  is forced stuck against the trailing edge  63 . Consequently, when the tool  50  is lifted from the cleaning surface  40  in order to reverse the direction of travel, the bristle assembly  53  fails to return to the centre of the suction opening  60 . The through-holes  78 , 79  in the carrier  70  prevent this from happening. The through-holes  78 , 79  provide a passageway between the leading side and the trailing side of the bristle assembly  53 . The through-holes  78 , 79  thus act to better equalise the pressure on the two sides of the bristle assembly  53 . The through-holes do not necessarily result in perfect equalisation. However, the through-holes  78 , 79  ensure that the pressure difference is not excessive. Consequently, when the tool  50  is lifted from the cleaning surface  40 , the resilience of the carrier  70  is sufficient to overcome the pressure difference and return the bristles assembly  53  to the centre of the suction opening  60 . 
     Any through-holes in the carrier  70  may present a trap for fluff or other dirt. If the through-holes were too small, the through-holes may become blocked altogether. Larger through-holes will naturally reduce the likelihood of the through-holes blocking. However, as the number and sizes of the through-holes increase, the holes will have an increasing influence over the behaviour of the carrier  70 . In particular, an excessive number of holes or holes that are excessively large may cause the carrier  70  to flex in an undesired manner. The location, number and sizes of the through-holes  78 , 79  are therefore selected such that the bristle assembly  53  is prevented from sticking against the trailing edge  63  of the nozzle  51  whilst ensuring that the behaviour of the carrier  70  is not adversely affected. 
     The through-holes  78 , 79  are formed in a region of the carrier  70  that is proximate the rear  56  of the nozzle  51 . Since the connecting duct  52  is located at the rear  56  of the nozzle  51 , the suction within the nozzle  51  is generally greatest at the rear  56  of the nozzle  51 . Any pressure difference between the leading side and the trailing side of the bristle assembly  53  is therefore likely to be greatest at the rear  56  of the nozzle  51 . By locating the through-holes  78 , 79  in a region of the carrier  70  proximate the rear  56  of the nozzle  51 , the number of through-holes may be kept to a minimum whilst ensuring that adequate equalisation of pressure is achieved. 
     The through-holes  78 , 79  in the carrier  70  are of different sizes. In particular, the through-hole  78  closest to the rear  56  of the nozzle  51  is larger. Both through-holes  78 , 79  are of a size that is intended to make blockage of the holes  78 , 79  unlikely. By having through-holes  78 , 79  of different sizes, a larger hole  78  can be used towards the rear of the carrier  70  where the pressure difference between the leading and trailing sides of the bristle assembly  53  is likely to be greatest. Since the pressure difference further along the carrier  70  is likely to be smaller, a smaller hole  79  may be used. As a result, the effect that the through-holes  78 , 79  have on the behaviour of the carrier  70  can be kept to a minimum whilst ensuring that adequate equalisation of pressure is achieved. 
       FIGS. 15 to 21  illustrate a further vacuum cleaner tool  100 . As with tools  10 , 50  described above and illustrated in  FIGS. 3 to 14 , the tool  100  comprises a nozzle  101 , a connecting duct  102 , and a bristle assembly  103 . 
     The nozzle  101  is elongate in shape, with the length of the nozzle  101  being greater than the height and width. The cross-sectional shape of the nozzle  101  resembles that of a circular sector, with the sides  107 , 108  of the nozzle  101  forming the two radii and the base  106  of the nozzle  101  forming the arc of the sector. With the tools  10 , 50  illustrated in  FIGS. 3 to 14 , the height or width of the nozzle tapers from the rear to the front of the nozzle. In contrast, with the tool  100  illustrated in  FIGS. 15 to 21 , the nozzle  101  does not taper in height or width. The top  105  of the nozzle  101  includes a cylindrical spine which, as described below, serves to hold the bristle assembly  103 . 
     The nozzle  101  comprises a main suction opening  115  and an auxiliary suction opening  116 , each of which opens up into an internal cavity  117  within the nozzle  101 . The main suction opening  115  is formed in the base  106  of the nozzle  101  and resembles an elongate oval that extends from the front  109  to the rear  110  of the nozzle  101  and has straight side edges. Since the base  106  of the nozzle  101  is arcuate, the side edges  118 , 119  of the suction opening  115  are raised relative to the front  109  and the rear  110  of the nozzle  101 . Consequently, as with the tools  10 , 50  illustrated in  FIGS. 3 to 14 , when the base  106  of the nozzle  101  is brought into contact with the cleaning surface  40 , a gap  160  is created between the leading edge  118  and the cleaning surface  40 . Protective pads  120  formed of a tufted fabric are secured to the base  106  of the nozzle  101  so as to surround the main suction opening  115 . The auxiliary suction opening  116  comprises a notch formed in the front  109  of the nozzle  101 . As explained below, the auxiliary suction opening  116  helps to pick up dirt along the edge of a wall or the like as the tool  100  is drawn sideways along the wall. 
     Like the tools  10 , 50  described above and illustrated in Figured  3  to  14 , the connecting duct  102  is attached to the rear  110  of the nozzle  101  and is in fluid communication with the cavity  117  and thus with the suction openings  115 , 116  of the nozzle  101 . Again, the connecting duct  102  is intended to be attached to a hose, wand or the like of a vacuum cleaner (not shown). 
     The bristle assembly  103  comprises a carrier  130  to which a strip of bristles  131  is attached. 
     The carrier  130  is formed of a rigid material and comprises a platform  135 , two struts  136 , 137  that extend upwardly from the platform  135 , a beam  138  that extends between the two struts  136 , 137 , a cantilever arm  139 , and a pair of lugs  140 , 141 . 
     The platform  135  comprises a pair of wings  146 , 147  that extend along opposite sides of a central channel  145 . When viewed from below, the shape of the platform  135  mirrors the main suction opening  115  and thus resembles an elongate oval. Each wing  146 , 147  is elongate, has a straight side edge and curved front and rear edges. The side edge may be regarded as the tip of the wing  146 , 147 . Each wing  146 , 147  curves upwardly from the central channel  145  to the tip. As a result, the base of the platform  135  is curved. Moreover, the curvature of the base of the platform  135  mirrors that of the base  106  of the nozzle  101 . Each wing  146 , 147  includes a winglet  148  that extends upwardly from the tip of the wing  146 , 147 . A protective pad  149 , again formed of a tufted fabric, is secured along the length of each wing  146 , 147 . 
     The two struts  136 , 137  extend upwardly from the top of the platform  135 . More specifically, a first strut  136  extends upwardly from a front end of the platform  135 , and a second strut  137  extends upwardly from a point partway along the length of the platform  135 . 
     The beam  138  extends between the tops of the two struts  136 , 137 . 
     The cantilever arm  139  is an L-shaped arm that extends from the rear of the second strut  137 . Alternatively, the cantilever arm  139  could be a straight arm that extends upwardly from the top of the platform  135 . 
     A first lug  140  extends outwardly from the first strut  136 , and a second lug  141  extends outwardly from the cantilever arm  139 . The first lug  140  is cylindrical in shape, whilst the second lug  141  resembles a truncated cylinder, i.e. a cylinder cut by a plane. 
     As noted above, the nozzle  101  comprises a spine  111  that extends along the top  105  of the nozzle  101 . The top of the carrier  130  is then held within this spine  111 . The spine  111  comprises a channel and a retaining recess located at each end of the channel. The two lugs  140 , 141  of the carrier  130  are held within the recesses, whilst the beam  138  of the carrier  130  extends along the channel. During assembly, the first lug  140  is inserted into the recess at the front end of the spine  111 . The rear of the carrier  130  is then pushed upwards, causing the second lug  141  to contact the nozzle  101 . The second lug  141  has a ramped surface. Consequently, as the carrier  130  continues to be pushed upwards, the cantilever arm  139  is caused to pivot in a direction towards the front  109  of the nozzle  101 . With sufficient force, the cantilever arm  139  pivots to enable the second lug  141  to snap-fit into the recess at the rear end of the spine  111 . 
     When the carrier  130  is held within the nozzle  101 , the platform  135  acts to cover a large part of the main suction opening  115 . Consequently, the main suction opening  115  resembles as oval racetrack that extends around the platform  135 . The lugs  140 , 141  are held within the recesses such that the carrier  130 , and thus the bristle assembly  103 , is free to pivot relative to the nozzle  101 . As the carrier  130  pivots, the platform  135  contacts a side edge  118 , 119  of the nozzle  101 . As a result, pivotal movement of the carrier  130  is relatively limited. 
     The strip of bristles  131  comprises a row of bristles  150  held together by a spine  151  that extends along the top of the bristles  150 . The bristles  150  are formed of carbon fibre and are held together by moulding the spine  151  over the tops of the bristles  150 . The strip of bristles  131  is held within the channel  145  of the carrier  130 . The bristles  150  then protrude downwardly through the main suction opening  115  in the base  106  of the nozzle  101 . The channel  145  rises upwardly at the front of the carrier  130 . Consequently, the bristles  150  additionally protrude through the auxiliary suction opening  116  in the front  109  of the nozzle  101 . 
     The tool  100  of  FIGS. 15 to 21  is intended to be used in exactly the same way as the tools  10 , 50  described above and illustrated in  FIGS. 3 to 14 . In particular, the tool  100  is intended to be swept across the cleaning surface  40  in directions normal to the main suction opening  115 . As the tool  100  is swept forwards, the bristle assembly  103  pivots backwards. On pivoting backwards, a wing  146  of the carrier  130  contacts the trailing edge  119  of the nozzle  101  so as to create a seal along the trailing edge  119 . As a result, the main suction opening  115  is located primarily between the platform  135  of the bristle assembly  103  and the leading edge  118  of the nozzle  101 . 
     As the tool  100  is swept over the cleaning surface  40 , the base  106  of the nozzle  101  contacts the cleaning surface  40  at the front  109  and rear  110 . Since the leading and trailing edges  118 , 119  of the nozzle  101  are raised relative to the front and rear ends  112 , 113 , a gap  160  is again created between the leading edge  118  and the cleaning surface  40 , thus ensuring that dirt is free to pass under the leading edge  118 . As with the other tools  10 , 50 , the angle formed between the tool  100  and the cleaning surface  40  typically changes as the tool  100  is swept across the cleaning surface  40 . Since the base  106  of the nozzle  101  is curved, the front and rear ends  112 , 113  of the nozzle  101  that contact the cleaning surface  40  are curved. Consequently, as the angle of the tool  100  changes, the front and rear ends  112 , 113  rock over the cleaning surface  40  so as to provide a smooth transition. The protective pads  120  secured to the base  106  of the nozzle  101  provide the same benefits as that detailed above in connection with the tool  50  of  FIGS. 9 to 14 , i.e. the tool  100  may be swept more smoothly over the cleaning surface  40 , and the tool  100  is less likely to mark the cleaning surface  40 . Again, as noted above in connection with the tool  50  of  FIGS. 9 to 14 , although the protective pads  120  are formed of a tufted fabric, other materials may alternatively be used, e.g. felted fabric, an elastomeric foam having a low-friction coating, or a strip of very short and fine bristles. 
     The carrier  130  is held within the nozzle  101  such that the platform  135  is raised slightly relative to the base  106  of the nozzle  101 . Consequently, when the tool  100  is used on an even surface, the platform  135  does not normally contact the cleaning surface. However, should the tool  100  be used on an uneven surface, or should the front end  112  or rear end  113  of the tool  100  be pushed off the cleaning surface, the platform  135  may contact the cleaning surface. The base of the platform  135  has a curvature that mirrors that of the nozzle  101 . Consequently, should the platform  135  contact the cleaning surface  40 , it continues to be possible to rock the tool  100  over the cleaning surface  40 . The protective pads  149  secured to the platform  135  then provide the same benefits as those secured to the nozzle  101 . 
     The bristles  150  of the tool  100  are relatively short. Indeed, the portion of the bristles  150  that protrudes beyond the platform  135  has a length that is no greater than the width of each wing  146 , 147 . That is to say that the bristles  150  have an effective length (i.e. a length that protrudes beyond the carrier  130 ) that is smaller than the width of each wing  146 , 147 . Consequently, it is not possible for the bristles  150  to be drawn up into the nozzle  101  via the main suction opening  115 . 
     As air is drawn in through the main suction opening  115 , the winglets  148  help to straighten the airflow and thus reduce turbulence. As a result, less noise is generated by the airflow as it is drawn through the tool  100 . 
     The tool  100  of  FIGS. 15 to 21  has a number of advantages over the other two tools  10 , 50  illustrated in  FIGS. 3 to 14 . The tool  100  generally has improved suction at the front of the main suction opening  115 . In spite of the tapered height or width of the nozzle, the tools  1 , 50  of  FIGS. 3 to 14  may experience relatively poor suction at the front of the suction opening. In comparison to the tools  1 , 50  of  FIGS. 3 to 14 , the tool  100  of  FIGS. 15 to 21  has a smaller suction opening  115 , which is to say that the surface area of the suction opening  115  is smaller. Consequently, the suction around the suction opening  115  is better balanced and thus the suction at the front of the suction opening  115  is increased. However, simply reducing the size of the suction opening does not necessarily result in improved suction at the front of the suction opening. For example, one might reduce the width of the nozzle  11  of the tool  10  illustrated in  FIGS. 3 to 8  in order to achieve a smaller suction opening  20 . However, a narrower nozzle  11  would create a constriction at the junction between the nozzle  11  and the connecting duct  12 . As a result, the flow of air through the tool  10  would be constricted and thus the suction at the front of the suction opening  20  would actually worsen rather than improve. With the tool  100  of  FIGS. 15 to 21 , a relatively small suction opening  115  is achieved whilst maintaining a relatively wide and tall nozzle  101 . This is made possible by the platform  135  of the carrier  130 , which acts to cover a large part of the main suction opening  115 . As a result, a constriction in the nozzle  101  is avoided and the suction at the front of the suction opening  115  is improved 
     The tool  100  of  FIGS. 15 to 21  has an auxiliary suction opening  116  at the front  109  of the nozzle  101 . This then has the benefit of improving dirt pickup along edges of the cleaning surface  40 . For example, when using the tool  100  up against a wall or the like, a user is able to abut the front  109  of the tool  100  against the wall and then sweep the tool  100  sideways in a direction parallel to the wall. Dirt that collects at the edge between the cleaning surface and the wall is then be drawn into the nozzle  101  via the auxiliary suction opening  116 . 
     The strip of bristles  131  is secured to the carrier  130  such that the bristles  150  extend through and beyond the auxiliary suction opening  116 . This then has two advantages. First, it acts to increase the length and thus the coverage of the strip of bristles  131 . Second, it enables the bristles  150  to better penetrate edges and corners. Conceivably, one could also provide an auxiliary suction opening at the rear  110  of the nozzle  101  and the strip of bristles  131  may be secured to the carrier  130  such that the bristles  150  extend through and beyond this additional opening. This would then further extend the length of the strip of bristles  131 . However, a notch in the rear  110  of the nozzle  101  is likely to adversely affect the suction at the auxiliary suction opening  116  and at the front of the main suction opening  115 . 
     As with the tool  50  of  FIGS. 9 to 14 , the bristle assembly  103  is attached to the top  105  of the nozzle  101 . The carrier  130  then comprises a through-hole  142  so as to equalise the pressure on the two sides of the bristle assembly  103 . However, unlike the tool  50  of  FIGS. 9 to 14  which has two relatively small through-holes  78 , 79 , the through-hole  142  in the carrier  130 , which is delimited by the platform  135 , the two struts  136 , 137  and the beam  138 , is relatively large. Having a relatively large through-hole  142  is made possible because the carrier  130  is formed of a rigid material. A large through-hole  142  has at least two advantages. First, pressure equalisation is improved and therefore the chances of the bristle assembly  103  sticking against the trailing edge  119  of the nozzle are much reduced. Second, the likelihood of dirt blocking the through-hole  142  is reduced. Indeed, with the tool  100  of  FIGS. 15 to 21 , the height of the through-hole  142  is larger than the width of the main suction opening  115 . Consequently, it should not be possible for dirt drawn in through the main suction opening  115  to become trapped in the through-hole  142 . 
     In the embodiment described above, the carrier  130  comprises a beam  138  that extends between the two struts  136 , 137 . However, the beam  138  offers little technical benefit and may be omitted. Accordingly, in a broader sense, the tools  50 ,  100  of  FIGS. 9 to 21  may be said to comprise a carrier  70 , 130  that is attached to the top  59 , 109  of nozzle  51 , 101 , and a passageway(s)  78 , 79 , 142  that extends through or over the carrier  70 , 130 . The passageway(s)  78 , 79 , 142  extends between the leading side and the trailing side of the bristle assembly  53 , 103  so as to better equalise the pressure on the two sides of the bristle assembly  53 , 103 .