Patent Publication Number: US-2007113375-A1

Title: Vacuum cleaners and hoses

Description:
This invention relates to vacuum cleaners of the kind including a suction unit and a flexible hose assembly.  
      Cylinder vacuum cleaners are used with a hose. Upright vacuum cleaners may also be used with a hose where it is necessary to clean less accessible locations. Hoses are also used in central vacuum cleaner installations, where a suction unit and ducting is built into a building. A long hose is useful in some situations but causes problems with storage and manipulation. The length of a hose is usually a compromise between a long length for ease of use and a short length to facilitate storage. One form of hose that can be long yet is easy to store is the extensible or stretch hose, which has a naturally short length but can be pulled to extend it to a longer length. The hose has a helical reinforcement with a natural contracted length but which can be extended resiliently. Although these hoses can by used satisfactorily, they have a disadvantage because the force needed to extend the hose and to maintain its extension makes it more difficult to manipulate the cleaning head. Furthermore, the force may pull over or move the vacuum cleaner or any furniture around which the hose is lead. One solution to this is the retractable hose, which has a naturally extended length and which can be retracted by suction. This is achieved by selecting the resilience of the helical reinforcement of the hose so that the suction created by the vacuum cleaner when the far end of the hose is obstructed is sufficient to pull the hose to a retracted length. The hose is then held in its retracted state so that it does not extend when the vacuum cleaner is turned off. This form of retractable hose is described in WO 03/024294. Although this form of hose has many advantages, there may be situations where it is desirable to have a hose that can be extended to even longer lengths but without an increased storage length, or where the construction of the hose does not allow for it to be retracted by suction, or where a non-retractable form of hose is preferred.  
      It is an object of the present invention to provide an alternative vacuum cleaner and hose.  
      According to one aspect of the present invention there is provided a vacuum cleaner of the above-specified kind, characterised in that the hose assembly includes at least two flexible sections one of which has a smaller external diameter than the other and is slidable within the other, and that the two sections are arranged to seal with one another at least when the two sections are extended relative to one another.  
      The flexible sections are preferably corrugated. The smaller diameter section may be stretchable from a natural short length to a longer length by applying an axial force. Alternatively, the smaller diameter section may be retractable from a natural extended length to a shorter length, such as by suction applied by the suction unit when the end of the hose assembly is occluded. The shorter length of the smaller diameter section may be substantially equal to the length of the larger diameter section. The two sections of the hose assembly may be provided with cooperating couplings that can be engaged with one another to retain the two sections in a compact configuration one within the other for storage. The larger diameter section of the hose assembly may be stretchable from a natural short length to a longer length by applying an axial force.  
      According to another aspect of the present invention there is provided a hose assembly for a vacuum cleaner, characterised in that the hose assembly includes inner and outer corrugated, flexible sections, that the inner section has a first end slidably retained within the outer section, that the hose assembly has a short configuration where the major part of the length of the inner section extends within the outer section and the first end of the inner section is located adjacent the first end of the outer section, and that the hose assembly has a longer configuration where the inner section is extended beyond a second end of the outer section and the first end of the inner section is located adjacent the second end of the outer section and in which a seal is provided between the two sections.  
      The inner section is preferably extensible from a shorter length substantially equal to the length of the outer section to a longer length greater than that of the outer section.  
    
    
      A vacuum cleaner including a hose assembly and its method of use, according to the present invention, will now be described, by way of example, with reference to the accompanying drawing, in which:  
       FIG. 1  is a simplified perspective view of the cleaner and hose assembly in an extended state; and  
       FIG. 2  is a simplified enlarged cross-sectional view of a part of the hose assembly in an extended state. 
    
    
      With reference first to  FIG. 1  there is shown a vacuum cleaner including a suction unit  1 , a hose assembly  2  and a cleaning wand  3  with a cleaning head  4  at one end.  
      The unit  1  is conventional, being a portable cylinder cleaner with a pump, dust collection bag, controls and filters of the usual kind (not shown). The unit  1  has a suction inlet  10  towards one end to which the hose assembly  2  is connected.  
      With reference now also to  FIG. 2 , the hose assembly  2  has a first, outer section  20  with a coupling  21  at one end connected with the suction inlet  10 . The main part of the first section  20  is provided by a corrugated, flexible tubular wall  22  of a plastics material, which is reinforced by a helical wire  23 . The invention is also applicable to other forms of hose, such as those made entirely of plastics. The end of the first section  20  remote from the vacuum cleaner housing  1  is terminated by a sealing coupling  24 . The first section  20  of the hose assembly  2  is typically about 1.8 m long and is relatively inextensible axially. The first hose section  20  may alternatively be of a stretch construction, that is, one that has a natural short, retracted length but can be pulled by applying an axial force to a longer length against the axial resilience of the hose.  
      The hose assembly  2  also has a second, inner, smaller diameter section  25 , which is flexible and corrugated, being provided by a sleeve  26  of a highly flexible plastics material supported on the outside of a helical reinforcement member in the form of a spring metal wire  27 , as described in WO03024294. The helical reinforcement wire  27  has a natural extended state but can be compressed axially against its resilience by an applied external force. The sleeve  26  is sufficiently flexible that the second section  25  itself naturally takes up the extended length of the reinforcement wire helix  27 . The sleeve  26  has shallow hills extending outwardly between turns of the reinforcement wire  27 , thereby allowing the sleeve to fold outwardly when the hose is retracted. The second section  25  is terminated at one end by a rigid circular end fitting  28  located within the first, larger diameter section  20  and freely slidable along it. The dimensions of the end fitting  28  and the coupling  24  on the first section are such as to prevent withdrawal of the end fitting. The end fitting  28  and the coupling  24  have engaging sealing surfaces  29  and  30  that extend laterally and abut and seal with one another when the end fitting is pulled against the coupling. The natural, extended length of the second section  25  is about 3.6 m and it can be retracted to a length of about the same as that of the first section, that is, about 1.8 m. This gives a total maximum length of about 5.4 m. In general, if both sections of the hose are non-retractable or non-compressible the minimum overall length of the hose will be about 50% of its maximum length. Where one of the hose sections is retractable, as described above, the same maximum length can be achieved but the minimum length can be only about 25% of the maximum.  
      The opposite end of the second section  25  is terminated by a handle  32 , such as of the kind described in GB2403403. The rear end of the handle  32  is formed with a coupling  33  adapted to mate with the coupling  24  at the end of the first section  20 . The handle  32  has a trigger  34  that can be operated by the user to close a valve (not shown) within the handle and thereby prevent or restrict flow of air through the handle and hence along the hose assembly  2 . The cleaning wand  3  is connected to the forward end of the handle  32 .  
      Before use, the second section  25  is retracted and withdrawn within the first, outer section  20 , as shown by the broken lines in  FIG. 2 , and is held in this retracted state by engagement of the couplings  33  and  24 , thereby providing a relatively compact configuration for storage. The hose assembly  2  can be used in this compact configuration for cleaning where a longer length is not needed. A stretch construction of the first section  20  facilitates use in this compact configuration. Normally, however, the user would release the two couplings  33  and  24  so that the resilience of the second section  25  extends it to its natural extended length. The user then pulls the second section  25  slightly to pull it out of the first section  20  to its maximum extent, in a telescopic fashion. Until the end fitting  28  is pulled into sealing engagement with the coupling  24 , air will be able to flow between the outside of the second section  25  and the coupling on the first section  20 , so the suction effect at the cleaning head will be reduced. Once the end fitting  28  is engaged with the coupling  24 , a seal is formed between the surfaces  29  and  30  preventing leakage of air into the hose assembly  2  except at the cleaning head  4 . The total length of the extended hose assembly  2  is, therefore, equal to the combination of the length of the first section  20  and the extended length of the second section  25 , that is, about  5 . 4 m. It will be appreciated that, if the first, outer section  20  has a stretch construction, the overall effective length of the entire hose assembly can be further extended by applying a light pulling force to the remote end of the assembly.  
      When the user has finished cleaning and wishes to store the cleaner, he closes the trigger  34  on the handle  32  to restrict air flow along the hose assembly  2 . This creates a suction pressure within the hose assembly  2  thereby retracting the second section  25  in length. The suction also has the effect of withdrawing the second section  25  back into the first section  20 , telescopically, like a piston. Once the end fitting  28  is displaced from the coupling  24 , some air will flow into the first section  20  at the coupling but it is still easy for the user fully to retract the second section  25  into the first with the combination of the suction and some manual guiding and pushing. When the second section  25  has been withdrawn fully into the first section  20  and has been retracted in length, the coupling  33  on the handle  32  is engaged with the coupling  24  on the first section. The vacuum cleaner can now be turned off allowing pressure within the hose assembly  2  to rise to atmosphere. The tendency of the second section  25  to extend is restrained by engagement of the couplings  33  and  24 .  
      By providing for the second section  25  to slide within the first section  20  the overall effective length of the hose assembly  2  can be further extended over the arrangement described in WO03024294 without any increase in the stowed length of the hose assembly. Or, the same extended length can be achieved with a hose assembly having reduced stowed length.  
      The invention could also be used with conventional hoses that cannot be extended or retracted in length. In the simplest case, the user would simply pull the smaller diameter hose out of the larger diameter hose to its full extent when cleaning and would push the two hoses telescopically together when the vacuum cleaner is to be stored. This enables the effective usable length of the hose to be up to twice that of the stowed length. In a modification of this arrangement employing conventional hose sections, the remote end of the hose assembly could have a valve similar to that described above that the user can close so that suction is created within the hose assembly. The suction helps produce a telescopic piston effect to withdraw the smaller diameter hose into the larger diameter hose.  
      It will be appreciated that the hose assembly could have various different configurations. For example, the hose assembly could include three or more hose sections of different diameters nested one within the other, so that the effective, usable, extended length of the hose is three or more times the stowed length. The larger diameter section could be secured at the remote end of the hose assembly and the smaller diameter section secured with the vacuum cleaner housing. The hose need not have a wire-reinforced construction but could, for example, be a low cost hose made entirely of plastics material.  
      The seal between the different sections of the hose need not be provided by abutting lateral surfaces but could instead be provided by one or more sliding seals, such as provided on the outer section facing inwardly to make a wiping seal with the outside of the inner section, or on the inner section facing outwardly to make a wiping seal with the inside of the outer section, or both of these arrangements.  
      The invention is not confined to portable cylinder cleaners but could be used with upright cleaners, central vacuum cleaner installations, fixed garage forecourt vacuum cleaners or the like.