Patent Application
20180014706
This application claims the priority of United Kingdom Application No. 1612136.0, filed Jul. 13, 2016, the entire contents of which are incorporated herein by reference.
The present invention relates to a flexible duct for a vacuum cleaner. More specifically, the present invention relates to a flexible duct for a vacuum cleaner tool.
The tools 100, 200 shown in
In a first aspect, the present invention provides a vacuum cleaner tool comprising a flexible duct, the flexible duct comprising a helical frame comprising a plurality of loops arranged about a helical axis and being formed of a rigid material, and a helical strip provided between the loops to seal the frame and being formed of pliable material; wherein the helical strip has indents on an exterior surface of the duct, and the helical strip is secured to the loops such that the interior surface of the helical strip is flush with the interior surface of the loops.
A flexible duct with smooth inner surface can be achieved by providing helical strip which is secured flush with the frame of the duct. This is in contrast to ducts of the prior art, which have sheaths covering the frame, so that the inner surface of the duct includes the frame. A disadvantage with having a frame in the duct is that the corrugations of the frame can introduce turbulence in the airflow through the duct. This in turn reduces the suction at the open nozzle end of the duct, or tool. This also means that the pick-up efficiency of the tool is adversely affected. A duct with a smooth profile reduces these losses without compromising on the flexibility of the duct. It has been found that an improved duct can be achieved by having the helical strip provided flush on the helical frame, such that the inner surface of the strip is smooth with the inner surface of the loops of the helical frame.
The helical strip is used to seal the space between the rigid frame loops and may be in the form of a single ribbon, or a series of bands that together provide a sealed duct. In other words, the helical strip is used to link the loops of the helical frame. The helical strip may be overmoulded or bonded onto a part of the helical frame. The helical strip is also provided with indents on the exterior surface of the flexible duct. The indents improve the flexibility of the duct and by providing a crease for the duct to fold into as it flexes. The exterior indents provide these advantages without being detrimental to the advantages achieved by the provision of a duct with a smooth inner surface.
Each loop may comprise a central band with at least one wing, the helical strip being secured to the at least one wing. Although at least part of the helical frame may remain uncovered to the user (i.e. the central band), the helical strip can be used to cover parts of the loops, for instance, the at least one wing on the loops can be covered or concealed by the helical strip whilst the central band is uncovered or exposed.
The at least one wing may extend all the way around the central band in a direction parallel with the helical axis, and the height of the at least one wing may be less than the height of the central band in a direction normal to the helical axis. A greater contact area with the helical strip can be achieved by having a wing that has the same shape as, and extends away from, the edge of the central band. In addition, the strength of the at least one wing is increased if it extends around the central band of each loop. For at least these two reasons, it can be said that the robustness of the duct is improved such that damage to the duct or tool can be prevented. The cross-sectional profile of each loop has a raised section, which is the central band, and lower section, which is the at least one wing. Thus, it can be said that the height of the at least one wing may be less than the height of the central band in a direction normal to the helical axis. The central band may be flanked by a wing on each side, so that the general profile of each loop can be said to have a raised central section (i.e. the central band) flanked by two lower sections (i.e. the wings). Both the inner and outer surfaces of the helical strip are provided flush with each of the central band once the strip is secured to the frame.
The at least one wing may have at least one anchor for securing the helical strip to the frame. The at least one anchor point may be a hole, or a keying feature that engages with the helical strip allowing for a more robust tool. The helical strip is provided only in the space between the loops of the frame. Thus, the anchor points allow the tool to withstand flexing without the helical strip coming away or unravelling from the frame. This is to be avoided as the helical strip provides a means for sealing the duct.
The cross section of the flexible duct may be a general rectangular shape, comprising two longer side surfaces connected by shorter top and bottom surfaces. The general rectangular shape of the flexible duct allows for a narrow profile crevice tool that can fit into most gaps and crevices. The requirement of a general rectangular shape does not preclude the curving or shaping of the sides of the rectangular duct for aesthetic or ergonomic purposes.
The indents may be provided on a side surface of the flexible duct. This allows for improved flexing of the duct in the desired side to side (or left/right) direction, instead of flexing in an up/down direction.
The tool of the present invention may be a telescopic tool comprising a first and second conduit, the first conduit has a narrower profile than the second conduit, the second conduit surrounds the first conduit such that the first conduit slides in and out of the second conduit allowing for extension of the tool, and the flexible duct forms part of the first conduit. The use of the flexible duct on a telescopic tool allows for a longer tool that can be placed into gaps or crevices to be cleaned. Furthermore, the provision of a rigid conduit together with a conduit having the flexible duct improves the handling and manoeuvrability of the tool since the user can hold onto the rigid conduit and steer to the tool.
In a second aspect, the present invention provides a vacuum cleaner duct comprising a flexible duct, the flexible duct comprising a helical frame comprising a plurality of loops arranged about a helical axis and being formed of a rigid material, and a helical strip provided between the loops to seal the frame and being formed of pliable material, wherein the helical strip has indents on an exterior surface of the duct; and the helical strip is secured to the loops such that the interior surface of the helical strip is flush with the interior surface of the loops.
In order that the present invention may be more readily understood, an embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:
The first conduit 2 is connected at one end to the second conduit 3 and at the opposite end to the first connector 4. The second conduit 3 is connected to the second connector 5. The second connecter 5 is located at the end opposite to where the first conduit 2 connects to the second conduit 3. The first connector 4 can be used for connecting a nozzle or cleaner head to the end of the tool 1. Alternatively, the first connector 4 can act as an inlet for the tool without the need for a nozzle or cleaner head attachment. The second connector 5 is used to connect the tool 1 to a wand or hose that further connects to a vacuum cleaner.
The tool 1 further comprises locking means 6 for locking the conduits 2,3 of the tool 1 out at maximum extension (as shown in
The first conduit 2 comprises a flexible portion or duct 7 and rigid portions 8 at either end of the flexible duct 7. The flexible duct 7 is shown in more detail in
The helical frame 9 is formed of a single piece of rigid material and comprises a plurality of loops 16 that are arranged around the helical axis 15. The loops 16 are spaced at regular intervals along the helical axis 15 with a space between each loop 16. The profile of each loop 16 is shown in more detail in
The helical strip 10 is formed of a single piece of a pliable material in the form of a tape, bandage or ribbon. The helical strip 10 is extends along the helical axis 15 and around part of the helical frame 9. Specifically, the helical strip 10 is either overmoulded onto or bonded to the helical frame 9 such that the strip 10 fills the space between each of the loops 16, providing a continuous coupling between the loops 16 of the frame. The helical strip 10 seals the spaces in the helical frame 9 to provide a duct for fluid to be drawn through. Furthermore, the helical strip 10 is provided between the loops 16 only on the wings 18, 19, such that the exterior of the helical strip 10 is flush with the exterior of the central band 17. As shown in
The helical strip 10 is able to flex and stretch, allowing the flexible portion 7 to bend or twist from a straight position and return back to its original shape. The helical strip 10 has indents 22 provided on the side surfaces 11, 12 of the duct 7. The indents 22 improve the flexibility of the duct 7 in two ways. Firstly, the indents 22 reduce the stiffness of the helical strip 10 on a side surface 11, 12 that lengthens during a flexing movement (that is to say, the side surface 11, 12 on the outside of the bend of the flexible duct portion 7). Secondly, the indents 22 allow for the material of the helical strip 10 to crease and fold more readily on a side surface 11, 12 that contracts during a flexing movement (that is to say, on the side surface 11, 12 on the inside of the bend of the flexible duct portion 7).
The anchors 20 provided on the wings 18,19 of each loop 16 of the frame 9 act as keying features as the strip 10 is overmoulded onto the frame 9. During manufacture, the pliable material flows over the wings 18, 19 and into or onto the anchors 20. The anchors 20 are holes that are shaped so that the helical strip 10 is secured onto the frame 9 once the pliable material has cured. The pliable material is only provided on the wings 18, 19 such that, once cured, the exterior surface of the helical strip 10 is flush with the exterior of the central band 17. In addition, a mould insert can be placed inside the flexible portion 7 of the first conduit 2 and against the inside surface of the loops 16 such that the pliable material flows and cures against the mould insert. The mould insert is then removed after curing to leave behind a smooth interior surface of the duct 7 as the helical strip 10 is cured flush with the interior profile of the loops 16.
During use, the tool 1 is extended so that the first conduit 2 is exposed as it slides outs of the second conduit 3. The travel of the first conduit 2 is locked when the tool 1 is in an extended position (as shown in
As the tool 1 is manoeuvred into a crevice, the flexible duct 7 of the first conduit 2 can bend or flex against the walls or floor of the crevice. The user will naturally force the tool 1 against the surface/floor of the crevice to be cleaned. As the force is applied, the flexible duct 7 will flex in an up/down and/or left/right direction. As the duct 7 bends or flexes in the up down direction, the projections 21 limit the range of movement of the helical frame 9. This improves the control of the tool 1 and gives the user the ability to steer the tool 1 in a crevice without the duct 7 flexing in an unwanted direction (i.e. up/down direction). In addition, prevents the flexing of the duct 7 beyond a point where damage or kinking would occur. Thus, although the maximum range in movement in the up and down direction is decreased, the duct 7 is protected against folding or kinking, and also reinforced to prevent any damage to the tool 1.
The movement of the flexible duct 7 in the left and right direction is improved by the indents 21 that are provided on the side surfaces of the helical strip 10. In use, the indents 21 provide improved flexibility, in that they are able to stretch more easily than the rest of the helical strip 10 since less material is present. In addition, the indents 21 provide a crease or fold for the helical strip 10 to bend into when flexing the duct 7. Thus, the steering of the tool 1 in a left/right direction is easier relative to steering in an up/down direction.
Although the flexible duct 7 is shown as part of a tool 1 for a vacuum cleaner, it will be appreciated that such a duct could be used on other parts of the vacuum cleaner, such as a suitable replacement for a hose, or a tube, or a conduit connecting parts of a vacuum cleaner.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1612136.0 | Jul 2016 | GB | national |
