Abstract:
The present invention relates to a vacuum cleaner ( 1 ) comprising a first casing ( 10 ) housing dust separation apparatus, a second casing ( 11 ) housing at least one filter ( 21, 23 ) or other component of the vacuum cleaner ( 1 ), a central spine ( 13 ) housing at least one conduit and forming part of an airflow path within the vacuum cleaner ( 1 ), the first and second casings ( 10, 11 ) lying generally parallel to one another and the central spine ( 13 ) lying at least partly between the first and second casings ( 10, 11 ). Such a construction provides a vacuum cleaner having a more compact profile which enables the vacuum cleaner to be used to clean areas where there is a height restriction, for example underneath furniture.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a vacuum cleaner. 
     2. Description of Related Art 
     An upright vacuum cleaner generally has a cleaner head rotatably mounted to the lower end of a main body in which dust separation apparatus is housed. A pair of wheels is mounted on the lower end to the main body or on the cleaner head. The cleaner head extends in a forward direction. A dirty air inlet is located at the forward end of the cleaner head and facing downwardly so that, in use, the dirty air inlet rests on the surface to be cleaned. Dirty air is sucked into the dust separation apparatus via the dirty air inlet by means of a fan driven by a motor. 
     Upright vacuum cleaners are commonly convertible into cylinder cleaners. In the cylinder mode, a wand or hose attached to the vacuum cleaner is used to provide the dirty air inlet instead of the dirty air inlet located in the cleaner head. This mode enables cleaning of confined areas which cannot be easily reached by the cleaner head, for example, stairs, underneath furniture etc. 
     Such conventional vacuum cleaners are bulky and therefore it is not possible to use the vacuum cleaner in its upright mode to clean some surfaces which are awkward to reach, in particular areas having a height restriction, for example under pieces of furniture such as beds, sofas and chairs. Therefore, to clean these areas it is necessary either to move the piece of furniture, which can be very difficult for large pieces of furniture, or to use the vacuum cleaner in its cylinder cleaning mode, which can be awkward, inconvenient and time consuming. Also, as these cleaners are so bulky, they take up considerable storage space which makes storing the vacuum cleaner, when not in use, difficult or awkward. 
     U.S. Pat. No. 4,373,228 discloses a vacuum cleaner having two cyclonic separators arranged side by side. A central rod holds an upper casing and a lower casing together. However, the presence of two separate cyclonic separators is a bulky construction and there is no space saving achieved by the provision of the central rod. 
     SUMMARY OF THE INVENTION 
     The present invention seeks to provide a vacuum cleaner which is less bulky in order to overcome the above disadvantages. 
     According to the present invention there is provided a vacuum cleaner comprising a first casing housing dust separation apparatus, a second casing housing at least one filter or other component of the vacuum cleaner, and a central spine, the first and second casings lying generally parallel to one another and the central spine lying at least partly between the first and second casings, wherein the central spine houses at least one conduit forming part of an airflow path within the vacuum cleaner and the conduit extends longitudinally in the same direction as the central spine. 
     In providing a vacuum cleaner having a central spine which lies partly between separate casing which house the dust separation apparatus and at least one filter or other component, the overall size (i.e. depth) of the cleaner can be minimized. Therefore, the vacuum cleaner can be used to clean areas having a much lower height restriction, as the reduced depth of the cleaner enables it to slide underneath furniture etc. Also the vacuum cleaner is more compact, making it less cumbersome to maneuver or carry and easier to store. 
     To further minimize the size of the vacuum cleaner, the central spine may lie wholly between the first and second casings. 
     The casings may be generally cylindrical in shape and arranged such that the longitudinal axis of each casing lies parallel to the longitudinal axis of the central spine. This helps to further reduce the size of the vacuum cleaner. 
     Further, the vacuum cleaner may comprise a cleaner head in which an inlet for dirty air is located, the cleaner head being rotatable with respect to the central spine and the first and second casings, wherein the depth of each casing is approximately equal to the height of the cleaner head, or wherein the depth of each casing is no greater than the height of the cleaner head. Therefore, when the central spine is tilted rearwardly so that the central spine, casings and cleaner head are almost horizontal, the height of the casings would be approximately the same as, or at least no greater than, the height of the cleaner head. In this horizontal position, the overall height of the vacuum cleaner is minimized, and the vacuum cleaner can be used to clean areas where there is a height restriction, for example underneath beds. 
     In a preferred embodiment, the vacuum cleaner comprises a conduit for transferring dirty air from an inlet for dirty air into the dust separation apparatus and a conduit for transferring dirty air from the dust separation apparatus to a first filter housed in the second casing. This means that the air flow path within the vacuum cleaner is integral with the central spine, further reducing the size of the cleaner. 
     To aid maintenance, cleaning and replacement of the dust separation apparatus or filters, the casings may be releasably attached to the central spine. 
     Preferably, the dust separation apparatus is a cyclonic separator, more preferably a dual cyclonic separator. Preferably, the second casing houses a first and a second filter which may be stacked coaxially on top of one another. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     An embodiment of the invention will now be described and fully explained with reference to the accompanying drawings, wherein: 
     FIG. 1 is a side view of a vacuum cleaner according to the present invention; 
     FIG. 2 is a front view of the vacuum cleaner of FIG. 1; 
     FIG. 3 shows the detail of the release mechanism of the casings of the vacuum cleaner of FIG. 1; and 
     FIG. 4 shows the internal detail and air flow path of the vacuum cleaner of FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to the FIGS. 1 to  3 , the vacuum cleaner  1  of the present invention comprises a cleaner head  3  having a downwardly directing dirty air inlet  5  at its forward end. The cleaner head  3  extends in a forward direction and is rotatably attached to the lower end of the main body  7  of the vacuum cleaner  1  via a motor housing  9 . The motor housing  9  is generally cylindrical and extends across the width of the cleaner head  3 . A pair of wheels  8  is mounted onto the motor housing  9  at the rear of the vacuum cleaner  1 . 
     The main body  7  comprises a first casing  10  and a second casing  11  releasably attached to a central spine  13 . The first and second casings  10 ,  11  are generally cylindrical. The longitudinal axis of each casing lies parallel to the longitudinal axis of the central spine  13 . The central spine  13  lies wholly between the first and second casings  10 ,  11 . 
     The casings  10 ,  11  and the central spine  13  are fixed onto the motor housing  9  so that the longitudinal axis of the motor housing  9  is perpendicular to the longitudinal axis of the central spine  13  and the first and second casings  10 ,  11 . The first and second casings  10 ,  11  are supported on either side of the central spine  13  so that the casings  10 ,  11  and the central spine  13  are in alignment along the length of the motor housing  9 . The base of each casing  10 ,  11  fits into a complementary recess  14  of the motor housing  9 . The diameter of each of the casings  10 ,  11  is approximately equal to the diameter of the motor housing  9  and is approximately equal to, or at least no greater than, the height of the cleaner head  3 . 
     A wand  20  is releasably attached to the rear of the central spine  13  of the vacuum cleaner  1 . The wand  20  comprises a generally straight hollow tube. It is detached from the central spine and used as the dirty air inlet when the cleaner is used in its cylinder cleaning mode as in known cleaners. 
     The first casing  10  houses a dust separation apparatus, for example a dual cyclonic separator S (shown in dotted lines on FIG.  4 ). The first casing  10  has a handle  15  extending outwardly from the rear of the main body of the vacuum cleaner to facilitate removal for emptying purposes. 
     The second casing  11  houses a first filter  23  stacked coaxially on top of a second filter  21 . The upper portion of the second casing  11  comprises an accessory tool holder  17  for holding accessory tools  19  for attachment to the wand  20  of the vacuum cleaner  1  for use as the dirty air inlet in the cylinder cleaning mode. 
     The first casing  10  has an upwardly extending curved handle  25 . The upper end of the handle  25  is releasably attached to the central spine  13  by a release mechanism  27  which may be a push-catch. The casing  10  can be released from the vacuum cleaner by pushing the catch  27  in the direction of the arrow X shown in FIG.  3 . The casing  10  can then be pulled away from the central spine  13  in the directions of the arrow Y shown in FIG.  2  and lifted out of the recesses  14  of the motor housing  9 . The second casing  11  can be made accessible by similar or alternative fastening meals. The second casing has a handle  25 ′ for aesthetic purposes and which can also function as a handle for lifting the vacuum cleaner off the floor if necessary. 
     The central spine  13  comprises a conduit  36  for transferring dirty air from the dirty air inlet  5  into the dust separation apparatus housed within the first housing  10  and a conduit for transferring dirty air from the dust separation apparatus into the second casing  11  housing the filters  21 ,  23 . Details of this are illustrated in FIG.  4 . The dirty air flows in the direction of the arrows Z indicated in FIG.  4 . The dirty air flows through the cleaner head  3  and enters the base of the conduit  36  of the central spine  13  via the inlet  37 . The dirty air then flows upwards towards an outlet  39  at the top of the conduit and into the dust separating apparatus, in this case a dual cyclonic separator, housed in the first casing  10 . Particles in the dirty air are separated out by the cyclonic separator. The cleaned air flows out of the separator via an outlet  41  and then passes through the first filter  23  and the second filter  21  via the inlets  43 ,  45  and  47  before exiting to the atmosphere. The airflow is also used to cool the motor before passing through the second filter  21 . 
     The wand  20  extends upwardly from the central spine  13  and the casings  10 ,  11 . The upper portion of the wand  20  forms a handle  29  having a gripping portion  31  extending forwardly and downwardly from the upper end of the wand  20 . The open, upper end of the wand  20  is sealed by a cap  33  which is movable between a closed and open position. The cap  33  extends in a rearward direction to form a hook integral with the cap  33  so that the cleaner can be hung up on a wall. 
     The power supply for the motor housed in the motor housing  9  is provided via a cable which enters the central spine at a point  35  just above the handle  25  of the first casing  10 . The cable extends down the central spine  13  to the motor housing  9  for electrical connection to the motor. The external part of the cable (not shown) is wrapped in a loop at the rear of the vacuum cleaner via a hook  37  fitted on the wand  20  when not in use. 
     In use, the user grasps the gripping portion  31  of the handle  29  and tilts the main body  7  of the vacuum cleaner I towards himself so that the cleaner head  3  extends in a forward direction. The vacuum cleaner is moved across the surface to be cleaned, and dirty air is sucked up through the dirty air inlet  5  into the cleaner head  3  and then into the dust separation apparatus housed in the first casing  10  by means of a fan driven by the motor. 
     Due to the reduced profile of the vacuum cleaner, it can be extended into areas where there is a height restriction, for example, underneath furniture. The vacuum cleaner is arranged so that the main body  7  can be tilted rearwardly so that the main body  7  and the cleaner head  3  are horizontal. In order to minimize the overall height of the vacuum cleaner  1  the diameter of the casings  10  and  11  is such that it is approximately equal to the height of the cleaner head  3 , or at least no greater than the height of the cleaner head. The clearance height of the vacuum cleaner is preferably around 140 mm. 
     The motor housing  9  is constructed to have minimal dimensions and has a diameter approximately equal to the diameter of the first and second casings  10  and  11 . The pair of wheels  8  at the rear of the vacuum cleaner  1  is also minimized in size. This helps to reduce the overall size of the vacuum cleaner and to reduce its weight to make it more compact. 
     In the light of this disclosure, modifications and equivalents of the described embodiment as well as other embodiments within the scope of the appended claims will now become apparent to a person skilled in the art.