GB2477138A

GB2477138A - A floor tool

Info

Publication number: GB2477138A
Application number: GB1001108A
Authority: GB
Inventors: Fang Xing Kow; Yong Chin Lim
Original assignee: Dyson Technology Ltd
Current assignee: Dyson Technology Ltd
Priority date: 2010-01-25
Filing date: 2010-01-25
Publication date: 2011-07-27
Anticipated expiration: 2030-01-25
Also published as: GB2477138B; GB201001108D0; WO2011089407A1

Abstract

A floor tool for a surface treating appliance includes a main body 12 having a suction opening 22, 24, and a conduit 14 connected to the main body 12 for conveying an air flow from the main body 12 to an air outlet 80. To reduce turbulence and noise generated during the passage of an air flow along the flow path, a plurality of apertures 102, 104, 106, 108 are formed in at least one of the main body 12 and the conduit 14. The apertures 102, 104, 106, 108, are open to the atmosphere to introduce air into a flow path extending from the suction opening 22, 24 to the air outlet 80, thereby disrupting the growth of the boundary layer in the air flow flowing along the flow path and inhibiting the transition to turbulent air flow within the boundary layer. Further sets of apertures (110, 112, 114, 116, 118, 120, fig 14) may also be provided on the underside of the floor tool. The apertures are preferably positioned at areas or increasing cross-section or areas with curves.

Description

A Floor Tool The present invention relates to a floor tool for a surface treating appliance. In its preferred embodiments, the present invention relates to a floor tool for a vacuum cleaning appliance.

Vacuum cleaners are generally supplied with a range of tools for dealing with specific types of cleaning. The tools include a floor tool for general on-the-floor cleaning. The floor tool comprises a main body which engages with a floor surface, and a conduit extending away from the main body for connection to a wand or hose of the vacuum cleaner. The main body has a lower surface comprising a suction opening through which, in use, a dirt-bearing air flow is drawn into the floor tool. The air flow is conveyed through a suction cavity of the main body to the conduit, which in turn conveys the air flow to the wand or hose of the vacuum cleaner.

As the air flow passes through the suction cavity of the main body and the conduit, shear stresses at the inner walls of the main body of the surfaces of the suction cavity and the conduit generate a boundary layer in the air flow. The thickness of the boundary layer increases as the flow progresses through the tool, which can result in a transition in the flow profile of the boundary layer from laminar flow to turbulent flow.

Pressure increases in the direction of the air flow through the floor tool, for example due to an increase in the cross-sectional area of the flow path through the tool or a bend in the flow path, can result in localised lifting of the boundary layer from the surface of the flow path, referred to as boundary layer separation, and an associated increase in the turbulence of the air flow. Consequently, regions which can be particularly susceptible to air turbulence include the interface between the main body and the conduit of the floor tool, and any articulated regions of the conduit for assisting the manoeuvring of the floor tool over the floor surface.

The generation of turbulence within the air flow passing though the floor tool results in the undesirable generation of noise. It is known, for example from US 5,517,716, to absorb noise generated by air turbulence through the introduction of noise absorbing material at various locations within the floor tool. However, the use of such material can increase the costs associated with the manufacture of the floor tool.

In a first aspect the present invention provides a floor tool for a surface treating appliance, comprising a main body having a suction opening, and a conduit connected to the main body for conveying an air flow from the main body to an air outlet, wherein the floor tool comprises a plurality of apertures open to the atmosphere for introducing air into a flow path extending from the suction opening to the air outlet to reduce turbulence generated during the passage of an air flow along the flow path.

Instead of absorbing the noise generated by air turbulence within the floor tool, the present invention seeks to reduce the air turbulence within the floor tool, and therefore decrease the noise generated by air turbulence. This is achieved through the disruption of the boundary layer generated in an air flow passing through the tool by re-energising the air flow to reduce the thickness of the boundary layer, and thereby inhibit the transition to turbulent flow, by the introduction of air into the air flow through apertures which are open to the atmosphere. This can delay the energy dissipation in mean flow to turbulence.

The apertures are preferably located so as to introduce air flow into the regions of the flow path which are most susceptible to boundary layer separation, for example due to variations in the cross-sectional area of the flow path or changes in the direction of the flow path through the tool. For example, at least some of the apertures may be arranged to introduce air into a region of the flow path having an increasing cross-sectional area.

Alternatively, or additionally, at least some of the apertures may be arranged to introduce air into a curved region of the flow path. As another alternative, at least some of the apertures may be arranged adjacent an interface between the main body and the conduit.

We have found that noise also tends to be generated in surfaces which are angled towards the direction in which air is drawn through the floor tool, due to the airflow tending to be "pulled" away from these surfaces. The location of these apertures in such surfaces can suppress this noise generation, and so at least some of the apertures are preferably located in a surface of the conduit or other part of the floor tool which is inclined relative to the direction in which air flows through the conduit or that part of the floor tool.

Preferably, the conduit comprises a head pivotably connected to the main body for movement relative thereto, and the plurality of apertures may comprise at least one aperture formed in the head of the conduit. The head of the conduit is pivotable relative to the main body about an angle which is preferably at least 60°, more preferably at least 80°. In a preferred embodiment, the head of the conduit is pivotable relative to the main body about an angle in the range from 90 to 180° as the head of the conduit moves from a fully lowered position. A stop member may be provided on one of the conduit and the main body to limit the angular movement of the conduit relative to the main body through contact between the stop member and the other one of the conduit and the main body.

The head preferably comprises a first port and a second port each for receiving an air flow from the main body. The ports may be conveniently located on opposite sides of the head to facilitate sealing between the conduit and the main body. Each port is preferably substantially circular, and the ports are preferably concentric. In a preferred embodiment the head is substantially cylindrical, with the first and second ports being located at opposing ends of the cylindrical head. The head has a longitudinal axis to which the first and second ports are preferably substantially orthogonal.

The plurality of apertures preferably comprises a first aperture for introducing air into the flow path downstream from the first port, and a second aperture for introducing air into the flow path downstream from the second port. The conduit preferably comprises a neck in which an air flow from the first port merges with an air flow from the second port, and the plurality of apertures may comprise a third aperture for introducing air into the merged air flow. This third aperture may be larger than each of the first and second apertures, which preferably have substantially the same size. The neck is preferably connected to the head substantially midway between the first and second ports, and preferably extends away from the head in a direction which is substantially orthogonal to the longitudinal axis of the head.

To further reduce turbulence within the conduit, the conduit preferably comprises means for directing air into the neck. This means may be provided in isolation from the apertures, and so in a second aspect the present invention provides a floor tool for a surface treating appliance comprising a main body connected to a conduit, the conduit comprising a head pivotably connected to the main body for movement relative thereto, and a neck connected to the head, the head comprising a first port and a second port each for conveying air into the conduit from the main body, and means for directing air entering the head into the neck.

The means for directing air into the neck preferably comprises a plurality of guide surfaces for guiding air into the neck. The guide surfaces are preferably connected to the inner surface of the head, with each guide surface preferably curving towards the neck. In one embodiment the guide surfaces are arranged in pairs, with each pair of guide surfaces arranged to guide an air flow entering the head through a respective port into the neck.

To provide a compact floor tool, the head comprises an outer surface which is preferably substantially flush with an adjoining portion of the main body in both fully raised and fully lowered positions of the conduit. The adjoining portion of the main body preferably comprises an upper section of the main body, with this upper section being located towards the rear of the main body. Where the head of the conduit has a substantially cylindrical outer surface, the upper section of the main body preferably has a substantially semi-cylindrical portion adjoining each end of the head of the conduit, with the radius of the semi-cylindrical portion being substantially equal to the radius of the head of the conduit.

The main body preferably comprises means for supporting the head of the conduit. The means for supporting the head preferably comprises a support surface. Where the head is cylindrical in shape, the support surface preferably has a radius of curvature which is substantially the same as that of the head. The support surface is preferably located above part of a suction channel of the main body. At least some of the plurality of apertures may be located in the support surface of the main body to introduce air into the flow path before, and preferably immediately before, the air flow enters the conduit.

The conduit comprises a rear section pivotably connected to the neck. The head and neck of the conduit may be considered to form a front section of the conduit, and so the conduit may be considered to comprise a front section pivotably connected to the main body and a rear section pivotably connected to the front section. This allows the conduit to be angled to assist in the pushing, or pulling, of the main body over the floor surface in a variety of orientations of the main body relative to, for example, a wand connected to the rear section of the conduit. The rear section is pivotable relative to the front section about an angle which is preferably at least 120°, more preferably of at least 150°. Stop members may again be provided, this time on one of the front section and the rear section, to limit the angular movement of the rear section relative to the front section through contact between the one of the stop members and the other one of the front section and the rear section.

The rear section of the conduit preferably comprises a substantially circular fluid inlet which is rotatably connected to a conformingly shaped fluid outlet of the front section of the conduit. The plurality of apertures preferably comprises a set of apertures formed in the rear section of the conduit, preferably towards or adjacent the fluid inlet of the rear section of the conduit.

Preferably each of the apertures is generally circular in shape. Each aperture preferably has a diameter in the range from 2 to 5 mm.

In a preferred embodiment the main body comprises a first suction channel for receiving a first dirt-bearing fluid flow, and a second suction channel for receiving the first dirt-bearing fluid flow from the first suction channel and a second dirt-bearing fluid flow.

This "division" of the main body into two interconnected suction channels can enable two different pressure regions to be established within the main body. A relatively high vacuum may be established in the second suction channel, which optimises the performance of the floor tool for capturing dirt and dust located within crevices in the floor surface. Simultaneously, a relatively low vacuum may be established in the first suction channel, which can improve the performance of the floor tool for capturing debris located on the surface of the floor tool without significantly impairing the capture of dirt and dust within crevices.

The first suction channel is preferably located towards the front of the main body, whereas the second suction channel is preferably located towards the rear of the main body. The head of the conduit is preferably supported above the second suction channel. The second suction channel preferably comprises an enlarged central portion extending rearwardly away from the first suction channel to enhance stability as the floor tool is manoeuvred in a return stroke over the floor surface.

The floor tool preferably comprises flexible floor engaging means located about the suction channels and between the suction channels for maintaining the pressure levels within the suction channels over the articulation range of the floor tool. Preferably, the floor tool comprises first flexible floor engaging means, preferably a plurality of bristles, filaments or at least one strip of flexible material, located about the suction channels, and second flexible floor engaging means, preferably also a plurality of bristles, filaments or at least one strip of flexible material, located between the first suction channel and the second suction channel. A series of relatively large castellations may be provided in a portion of the first floor engaging means adjacent the first suction channel to admit relatively large debris into the first suction channel during, for example, a forward stroke of the floor tool. A series of relatively small castellations may be provided in a portion of the first floor engaging means adjacent the second suction channel to admit relatively small debris into the second suction channel during, for example, a reverse stroke of the floor tool.

Dirt and debris may thus enter the second suction channel within three different fluid flows. A first dirt-bearing fluid flow enters the second suction channel from the first suction channel to convey relatively large surface-located debris into the second suction channel. A second dirt-bearing fluid flow enters the second suction channel through the relatively small castellations to convey relatively small surface-located debris into the second suction channel. A third dirt-bearing fluid flow enters the second suction channel between the first and second flexible floor engaging means to convey crevice- located dirt and debris into the second suction channel. The first and second dirt-bearing fluid flows may enter the second suction channel in substantially opposite directions, whereas the third dirt-bearing fluid flow may enter the second suction channel in a direction substantially orthogonal to one or both of the first and second dirt-bearing fluid flows.

The floor tool preferably comprises at least one intermediate channel located between the first suction channel and the second suction channel for conveying a fluid flow therebetween. The at least one intermediate channel is preferably co-planar with the suction channels, and may extend transversely to the suction channels. In a preferred embodiment the main body comprises a first intermediate channel and a second intermediate channel located on opposite sides of the main body. The intermediate channels may be defined by interruptions in the second floor engaging means, or by spaces between the first and second floor engaging means. Alternatively, or additionally, at least one intermediate channel may be formed in a housing of the main body which at least partially defines the suction channels.

The present invention also provides a surface treating appliance, preferably a vacuum cleaning appliance, comprising a floor tool as aforementioned. In a third aspect the present invention provides a surface treating appliance comprising a suction opening, an air outlet, and a plurality of apertures open to the atmosphere for introducing air into a flow path extending from the suction opening to the air outlet to reduce turbulence generated during the passage of an air flow along the flow path. The apertures may be located in a floor tool, a wand and/or a main body of the appliance.

Features described above in connection with the first aspect of the invention are equally applicable to the second and third aspects of the invention, and vice versa.

Preferred features of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a front perspective view, from above, of a first embodiment of a floor tool, with a conduit of the floor tool in a lowered position; Figure 2 is a front perspective view, from below, of the floor tool as positioned in Figure 1; Figure 3 is a top view of the floor tool as positioned in Figure 1; Figure 4 is a side view of the floor tool as positioned in Figure 1; Figure 5 is a front view of the floor tool as positioned in Figure 1; Figure 6 is a side sectional view along line V-V in Figure 3; Figure 7 is a front sectional view along line W-W in Figure 3; Figure 8 is a top sectional view along line X-X in Figure 5; Figure 9 is a top view of the floor tool of Figure 1, with the conduit in a raised position; Figure 10 is a side view of the floor tool as positioned in Figure 9; Figure 11 is a front view of the floor tool as positioned in Figure 9; Figure 12 is a front perspective view, from above, of a second embodiment of a floor tool, with a conduit of the floor tool in a lowered position Figure 13 is a front perspective view, from below, of the floor tool of Figure 12; Figure 14 is a rear perspective view, from above, of the floor tool of Figure 12; Figure 15 is a top view of the floor tool of Figure 12; Figure 16 is a front view of the floor tool of Figure 12; Figure 17 is a front sectional view along line C-C in Figure 15; Figure 18 is a top sectional view along line B-B in Figure 16; and Figure 19 is a side sectional view along line A-A in Figure 15.

With reference first to Figures 1 to 5, a first embodiment of a floor tool 10 comprises a main body 12 and a conduit 14 connected to the main body 12. The main body 12 comprises an elongate casing 16 comprising a lower section 18 and an upper section 20 located towards the rear of the main body 12. The lower section 18 comprises a first, front suction opening, or suction channel 22, and a second, rear suction opening, or suction channel 24, located adjacent to, and in the same plane as, the front suction channel 22. In use, both suction channels 22, 24 face a floor surface to be cleaned.

Each of the suction channels 22, 24 extends between opposite side edges 26, 28 of the casing 16. As illustrated most clearly in Figure 2, the rear suction channel 24 comprises an enlarged central portion 30 extending rearwardly away from the front suction channel 22 in the shape of a chevron to enhance stability as the floor tool 10 is manoeuvred over the floor surface.

The main body 12 comprises flexible floor engaging members located about the suction channels 22, 24, and between the suction channels 22, 24. In this embodiment, the floor engaging members comprises a first set of bristles 32 that is arranged in the form of a substantially continuous skirt about the suction channels 22, 24, and a second set of bristles 34 that is arranged in a substantially continuous linear row between the suction channels 22, 24. Alternatively, one or both of the sets of bristles 32, 34 may be replaced by at least one strip of flexible material. Each set of bristles 32, 34, is retained within a respective groove formed in the casing 16 of the main body 12. The first set of bristles 32 comprises a series of relatively large castellations 36 in the front section of these bristles 32, lying adjacent the front edge of the front suction channel 22, to admit relatively large debris into the front suction channel 22, for example, during a forward stroke of the floor tool 10. The first set of bristles 32 also comprises a series of relatively small castellations 38 in the rear section of these bristles 32, lying adjacent the rear edge of the rear suction channel 24, to admit relatively small debris into the rear suction channel 24, for example, during a reverse stroke of the floor tool 10.

Intermediate channels 40 are located between the front suction channel 22 and the rear suction channel 24 to provide fluid communication between the suction channels 22, 24.

The main body 12 comprises two intermediate channels 40 extending transversely between the suction channels 22, 24, with each intermediate channel 40 being located adjacent a respective side edge 26, 28 of the casing 16. In this embodiment, the row of bristles 34 does not extend fully between the side sections of the first set of bristles 32 so that each intermediate channel 40 is defined by a gap located between the first set of bristles 32 and a respective end of the row of bristles 34. Alternatively, the second set of bristles 34 may extend fully between the side sections of the first set of bristles 32, and at least one intermediate channel may be formed in the casing 16 of the main body 12 to convey fluid between the suction channels 22, 24.

The conduit 14 comprises a front section 50 and a rear section 52. The front section 50 is pivotably connected to the main body 12 for movement relative thereto about a first axis A1, indicated in Figures 3 and 6. The front section 50 comprises a head 54 pivotably connected to the main body 12, and a neck 56 extending from the head 54 to the rear section 52 of the conduit 14.

The head 54 is positioned within a recess located centrally in the upper section 20 of the casing 16. The head 54 has a longitudinal axis which is substantially co-linear with the first axis A1, and is connected to the upper section 20 of the casing 16 so that the head 54 is free to rotate about its longitudinal axis. The head 54 has a substantially cylindrical outer surface 58 which is open at each end. The upper section 20 of the casing 16 is shaped so that each portion 60 of the upper section 20 that adjoins a respective end of the head 54 is substantially flush with the outer surface 58 of the head 54. Consequently, each portion 60 of the upper section 20 of the casing 16 has a substantially semi-cylindrical outer surface.

With particular reference to Figures 7 and 8, a sealing member 62 is provided between each end of the head 54 and its adjoining portion 60 of the upper section 20 of the casing 16 to form a substantially air-tight seal therebetween. Each end of the head 54 provides a respective port 64 through which fluid enters the conduit 14 from the main body 12. Each port 64 is thus substantially circular, and is substantially orthogonal to the longitudinal axis of the head 54, and therefore the first axis A1, which passes centrally through each port 64. As a result, in use fluid passes into the head 54 through the ports 64 is opposing directions.

The neck 56 is connected to the head 54 substantially midway between the ports 64, and in this embodiment is integral with the head 54. The neck 56 extends away from the head 54 in a direction which is substantially orthogonal to the longitudinal axis of the head 54. Consequently, as fluid passes through the head 54 from one of the ports 64 and into the neck, the fluid changes direction by around 90°. To reduce turbulence within the head 54, the head 54 comprises two guide surfaces 66, each for guiding fluid entering the head 54 through a respective port 64 towards the neck 56. The guide surfaces 66 are preferably integral with the inner surface 68 of the head 54, and arranged so that each guide surface 66 curves away from the inner wall 68 towards the neck 56 to meet the other guide surface 66 at an apex 70 extending across the bore of the head 54.

The bottom of the recess within the upper section 20 of the casing 16 is delimited by a curved support surface 72 for supporting the head 54 of the front section 50 of the conduit 14. The support surface 72 is located centrally within the rear suction channel 24, and extends between the front and rear edges of the rear suction channel 24. The support surface 72 preferably has a radius of curvature which is substantially the same as that of the outer surface 58 of the head 54. In addition to supporting the head 54, the support surface 72 also serves to guide fluid into the head 54 from the rear suction channel 24, and to support part of the lower surface of the neck 56 of the front section of the conduit 14 when the front section 50 is in its fully lowered position as illustrated in Figures 1 to 8.

Returning to Figure 6, the rear section 52 of the conduit 14 is connected to the neck 56 of the front section 50 of the conduit 14 for pivotal movement relative thereto about a second axis A2 angled to the first axis A1. In this embodiment the second axis A2 is orthogonal to the first axis A1, and is inclined to the longitudinal axis L of the rear section 52, illustrated in Figure 4, in this embodiment by an angle of around 65°.

The connection between the front section 50 and the rear section 52 of the conduit 14 is effected by connecting a fluid outlet 74 of the neck 56 of the front section 50 of the conduit 14 to a fluid inlet 76 of the rear section 52 of the conduit 14. The fluid outlet 74 of the neck 56 is substantially cylindrical, and is angled downwardly (as illustrated in Figure 6) towards a floor surface to be cleaned. The fluid inlet 76 of the rear section 52 is also substantially cylindrical and is angled upwardly (as illustrated in Figure 6) away from the floor surface so that when the fluid inlet 76 is received within the fluid outlet 74, the longitudinal axis L of the rear section 52 of the conduit 14 is substantially horizontal when the front section 50 of the conduit 14 is in its fully lowered position.

This enables the floor tool 10 to have a relatively low profile when in its fully lowered position. The fluid inlet 76 of the rear section 52 is received within the fluid outlet 74 of the neck 56 so that the longitudinal axes of the fluid outlet 74 and the fluid inlet 76 are substantially co-linear with the second axis A2, and the fluid inlet 76 is rotatable relative to the fluid outlet 74 about the second axis A2. A sealing member 78 is located between the inner surface of the fluid inlet 74 and the outer surface of the fluid outlet 76 to inhibit fluid loss from therebetween.

The rear section 52 of the conduit 14 comprises a fluid outlet 80 which is connectable to a wand, hose or other such duct of a cleaning appliance which comprises dirt and dust separating apparatus and a motor-driven fan unit for drawing dirt-bearing fluid into the main body 12 of the floor tool 10.

In use, with the floor tool 10 located on a floor surface so that both the first set of bristles 32 and the second set of bristles 34 engage the floor surface, operation of the fan unit generates two different pressure regions within the main body 12. Due to the relatively tight seal formed around the rear suction channel 24 by the two sets of bristles 32, 34, a relatively high vacuum can be established in the rear suction channel 24. This can optimise the entrainment of dust and debris located within crevices in the floor surface within a fluid flow drawn into the rear suction channel 24 between the two sets of bristles 32, 34. A relatively small amount of this vacuum is sacrificed by the provision of (i) the relatively small castellations 38 in the first set of bristles 32, to enable dust and relatively small debris located on the floor surface to be entrained within a fluid flow drawn though the relatively small castellations 38 into the rear suction channel 24, and (ii) the intermediate channels 40 between the first set of bristles 32 and the second set of bristles 34.

The provision of the relatively small castellations 38 can reduce the amount of debris that builds up along the rear edge of the main body 12 as the floor tool 10 is manoeuvred in a reverse direction over the floor surface. On the other hand, the provision of these intermediate channels 40 establishes a relatively low vacuum in the front suction channel 22 to enable dust and relatively large debris located on the floor surface to be entrained within a fluid flow drawn into the front suction channel 22 through the relatively large castellations 36. This first, dirt-bearing fluid flow is conveyed from the front suction channel 22 through the intermediate channels 40 to the rear suction channel 24, where it merges with fluid drawn directly into the rear suction channel 24. The merged fluid flow passes into the upper section 20 of the casing 16 and through the ports 64 into the head 54 of the front section 50 of the conduit 14. The guide surfaces 66 within the head 54 guide the fluid flow into the neck 56. From the neck 56, the fluid flow passes into the rear section 52 of the conduit 14, and into a wand (not shown) connected to the fluid outlet 80 of the rear section 52.

As the floor tool 10 is manoeuvred over the floor surface, the flexibility of the bristles 32, 34 can enable the contact between the bristles 32, 34 and the floor surface, and thus the two different pressure regions within the main body 12, to be maintained over a wide range of orientations of the wand relative to the main body 12. Figures 1 to 8 illustrates the conduit 14 in a fully lowered position, in which the upper extremity of the floor tool 10 is only slightly higher than the uppermost extremity of the head 54 of the front section 50 of the conduit 14. This can enable the floor tool 10 to be manoeuvred beneath, for example, items of furniture located on the floor surface whilst maintaining contact between the bristles 32, 34 and the floor surface. During use, the conduit 14 can be raised from this fully lowered position, for example to facilitate manoeuvring of the floor tool 10 over an open floor surface, by raising the wand (not shown) connected to the fluid outlet 80, thus causing the head 54 of the front section 50 of the conduit 14 to pivot about the first axis A1.

By way of example, the front section 50 of the conduit 14 can be raised from the fully lowered position shown in Figures 1 to 8 to a raised position, shown in Figures 9 to 11, by pivoting the front section 50 of the conduit 14 relative to the main body 12 about an angle of around 110°. Simultaneously with, or separately from, the pivoting of the front section 50 of the conduit 14 relative to the main body 12, the rear section 52 of the conduit 14 may be pivoted relative to the front section 50 of the conduit 14 by turning the wand relative to the main body 12, which causes the fluid inlet 76 to rotate relative to the fluid outlet 74. For example, in the raised position shown in Figures 9 to lithe rear section 52 of the conduit 14 has been pivoted relative to the front section 50 of the conduit 14 by around 40°. In this raised position, a wand connected to the fluid outlet 80, may be substantially parallel to the main body 12 of the floor tool, enable the floor tool 10 to be pushed and pulled sideways by the user, for example into a relatively narrow gap between items of furniture or between an item of furniture and a wall, whilst maintaining the bristles 32, 34 in contact with the floor surface.

Figures 12 to 19 illustrate a second embodiment of a floor tool 100. This floor tool 100 differs from the floor tool 10 illustrated in Figures 1 to 11 in that the intermediate channels 40 located adjacent the side edges 26, 28 of the casing 16 have been replaced by intermediate channels 40a. As opposed to being located at the ends of the second set of bristles 34, the intermediate channels 40a are in the form of castellations, interruptions or other discontinuities in the second set of bristles 34. As illustrated in Figure 12, the intermediate channels 40a comprise a centrally located inner intermediate channel, and two outer intermediate channels. In comparison to the intermediate channels 40, the intermediate channels 40a can improve the passage of light, relatively bulky items of debris, such as dead flies, into the rear suction channel 24, which items could otherwise have a tendency to become trapped within the central part of the front suction channel 22 but without compromising significantly the performance of the rear suction channel 24 in capturing dirt and dust located within crevices in the floor surface.

The floor tool 100 also differs from the floor tool 10 illustrated in Figures 1 to 11 in that the floor tool 100 comprises a plurality of apertures open to the atmosphere for introducing air into a flow path extending from the rear suction channel 24 of the main body 12 to the fluid outlet 80 of the rear section 52 of the conduit 14. The introduction of air into this flow path can re-energise the air flow passing through the floor tool 100, thereby inhibiting its transition to turbulent flow and so reducing the amount of noise generated by the passage of the air flow through the floor tool 100.

With reference first to Figures 13, 17 and 18, the floor tool 100 comprises a first set of apertures 102, 104, 106, 108 formed in the support surface 72 of the main body 12 for supporting the head 54 of the front section 50 of the conduit 14. The apertures 102, 104, 106, 108 are formed in the support surface 72 for two reasons. First, the support surface 72 is substantially orthogonal to the direction in which air flows through the rear section 52 and the neck 56 of the front section 50 of the conduit 14, and so is liable to generate noise during use of the floor tool 100 due to the pull of air away from this surface by the fan unit of the cleaning appliance to which the floor tool 100 is attached.

Second, the ends of the support surface 72 are located adjacent a region of the flow path having an increasing cross-sectional area, and so is prone to boundary layer separation through the associated pressure increase in the air flow. The location of these apertures 102, 104, 106, 108 in the support surface 72 allows air to be drawn through the support surface 72 from the rear suction channel 24 and into the flow path adjacent the support surface 72 to re-energise the boundary layer of the air flow adjacent the support surface 72. This inhibits local transition of the air flow to turbulent flow, and thus suppresses the generation of noise at the portions of the support surface 72 which are exposed to the air flow through the floor tool 100.

The apertures 102, 104, 106, 108 are substantially circular in shape, and have a diameter of around 4 mm. This first set of apertures 102, 104, 106, 108 comprises four apertures arranged in pairs located on opposite sides of the support surface 72.

With reference now to Figures 14, 18 and 19, the floor tool 100 comprises a second set of apertures 110, 112, 114 located in the head 54 of the conduit 14. This is because the inner surface of the head 54 also presents a surface which is generally orthogonal to the direction in which air flows through the rear section 52 and the neck 56 of the front section 50 of the conduit 14, and so is liable to generate noise during use of the floor tool 100 due to the pull of air away from this surface by the fan unit of the cleaning appliance. Two of the apertures 110, 112 are each located so as to introduce air from the external environment into the air flow immediately after it enters the head 54 of the conduit 14 through a respective one of the ports 64 to re-energise the air flow and thus inhibit noise generation. These two apertures 110, 112 are substantially circular in shape, and have a diameter of around 2.5 mm. A third aperture 114 of the second set of apertures is located between the apertures 110, 112, and is located so as to introduce air into the head 54 of the conduit 14 at a location where the air flows merge downstream from the ports 64. This third aperture 114 is also substantially circular in shape, and has a diameter of around 3.5mm.

Turning now to Figures 12, 14, 18 and 19, the floor tool 100 further comprises a third set of apertures 116, 118, 120 located in the rear section 52 of the conduit 14. This third set of apertures 116, 118, 120 is located adjacent the fluid inlet 76 of the rear section 52 of the conduit 14. With reference back to Figure 6, there is another increase in the cross-sectional area of the flow path at the interface between the front section 50 and the rear section 52 of the conduit 14. Moreover, part of the rear section 52 adjacent the fluid inlet 76 is inclined relative to the direction in which air is drawn through the rear section 52 of the conduit 14, and so is liable to generate noise during use of the floor tool 100. Consequently, the introduction of air from the external environment into the flow path immediately downstream of the fluid inlet 76 of the rear section 52 can assist in preventing localised boundary layer separation within the rear section 52 of the conduit 14, and its associated turbulent air flow, through further re-energising the air flow through the floor tool 100.

As discussed above in connection with the floor tool 10, to reduce turbulence within the head 54 the head 54 comprises two guide surfaces 66, each for guiding air entering the head 54 through a respective port 64 towards the neck 56. With reference to Figures 17 to 19, in addition to these guide surfaces 66 the floor tool 100 comprises two additional guide surfaces 122 which are also arranged to guide air towards the neck 56. Each of the additional guide surfaces 122 is located adjacent a respective one of the guide surfaces 66, and, similar to the guide surfaces 66, is connected to the inner surface of the head 54 and shaped to curve towards the neck 56. Guide vanes 124 may also be provided on the inner surface of the neck 56 of the conduit 14 for guiding the air flow towards the rear section 52 of the conduit 14. Alternatively, or additionally, guide vanes may be provided on the inner surface of the rear section 52 of the conduit 14 to guide the air flow towards the fluid outlet 80 of the rear section 52 of the conduit 14.

The invention is not limited to the detailed description given above. Variations will be apparent to the person skilled in the art.

Claims

CLAIMS1. A floor tool for a surface treating appliance, comprising a main body having a suction opening, and a conduit connected to the main body for conveying an air flow from the main body to an air outlet, wherein the floor tool comprises a plurality of apertures open to the atmosphere for introducing air into a flow path extending from the suction opening to the air outlet to reduce turbulence generated during the passage of an air flow along the flow path.
2. A floor tool as claimed in claim 1, wherein at least some of the apertures are arranged to introduce air into a region of the flow path having an increasing cross-sectional area.
3. A floor tool as claimed in claim 1 or claim 2, wherein at least some of the apertures are arranged to introduce air into a curved region of the flow path.
4. A floor tool as claimed in any of the preceding claims, wherein at least some of the apertures are arranged adjacent an interface between the main body and the conduit.
5. A floor tool as claimed in any of the preceding claims, wherein at least some of the apertures are located in a surface of the conduit which is inclined relative to the direction in which air flows through the conduit.
6. A floor tool as claimed in any of the preceding claims, wherein the conduit comprises a head pivotably connected to the main body for movement relative thereto, and the plurality of apertures comprises at least one aperture formed in the head of the conduit.
7. A floor tool as claimed in claim 6, wherein said at least one aperture comprises at least three apertures.
8. A floor tool as claimed in claim 6 or claim 7, wherein the head comprising a first port and a second port each for receiving an air flow from the main body.
9. A floor tool as claimed in claim 8, wherein said at least one aperture comprises a first aperture for introducing air into the flow path downstream from the first port, and a second aperture for introducing air into the flow path downstream from the second port.
10. A floor tool as claimed in claim 8 or claim 9, wherein the conduit comprises a neck in which an air flow from the first port merges with an air flow from the second port.
11. A floor tool as claimed in claim 10, wherein the conduit comprises means for directing air into the neck.
12. A floor tool as claimed in claim 11, wherein the means for directing air into the neck comprises a plurality of guide surfaces for guiding air into the neck.
13. A floor tool as claimed in claim 12, wherein the guide surfaces are connected to the inner surface of the head.14. A floor tool as claimed in claim 13, wherein each guide surface curves towards the neck.
14. A floor tool as claimed in claim 13, wherein the guide surfaces are arranged in pairs, with each pair of guide surfaces arranged to guide an air flow entering the head through a respective port into the neck.
15. A floor tool as claimed in any of claims 9 to 14, wherein the conduit comprises a rear section pivotably connected to the neck, and wherein the plurality of apertures comprises a set of apertures formed in the rear section of the conduit.
16. A floor tool as claimed in any of claims 1 to 4, wherein the conduit comprises a front section connected to the main body and a rear section pivotably connected to the front section, and wherein the plurality of apertures comprises a set of apertures formed in the rear section of the conduit.
17. A floor tool as claimed in any of the preceding claims, wherein the plurality of apertures comprises a set of apertures located on a lower surface of the main body.
18. A floor tool as claimed in any of the preceding claim, wherein each of the apertures is generally circular in shape.
19. A floor tool as claimed in claim 18, wherein each of the apertures has a diameter in the range from 2 to 5 mm.
20. A floor tool for a surface treating appliance substantially as hereinbefore described with reference to the accompanying drawings.