Abstract:
A cleaning appliance includes a main body, including a motor and fan unit for generating an airflow, a separating apparatus for separating dirt and dust from the airflow and a passageway for receiving a filter. The passageway and a filter may be located downstream of the separating apparatus and upstream of the motor, and the filter may have an at least partially curved filter surface. The filter is arranged around at least a part of the motor and fan unit. The filter is removable through a side, and through a wheel, of the appliance. The arrangement facilitates ease of removal of the filter from the cleaning appliance.

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application claims the priority of United Kingdom Application No. 0720971.1, filed Oct. 25, 2007, the contents of which are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The invention relates to a cleaning appliance, such as a vacuum cleaner. 
     BACKGROUND OF THE INVENTION 
     Vacuum cleaners are designed to separate dirt and dust from an airflow. Commonly, a motor and fan unit generates an airflow which draws dirt- and dust-laden air into the vacuum cleaner through a dirty air inlet. The airflow then passes through a form of separating apparatus such as a porous bag or a cyclonic separator (see, for example, EP 0 042 723) to remove dirt and dust from the airflow. 
     Irrespective of the type of separating apparatus used, there may be a risk of a small amount of dirt and dust passing through the separating apparatus and being carried to the motor and fan unit. It is undesirable for dirt and dust particles to pass through the fan of a motor and fan unit because the fan may become damaged or may operate less efficiently. In order to reduce this problem, some vacuum cleaners include a fine filter in an airflow path between the separating apparatus and the airflow generator (see, for example, GB 2 320 419). This filter is commonly known as a pre-motor filter and is used to extract any fine dirt and dust particles remaining in the airflow after it has passed through the separating apparatus. 
     It is also known to provide a filter in an airflow path downstream of the airflow generator in order to extract any remaining dirt and dust particles prior to the airflow exiting the appliance. This type of filter is known as a post-motor filter. The post-motor filter also captures particles produced by the brushes of the motor. The post-motor filter may be of the High Efficiency Particulate Air (HEPA) type, to remove very small particles from the airflow, such as smoke and allergens. 
     Filter assemblies for removing dust or debris from the air stream of a vacuum cleaner or other dust retaining appliances are therefore common. Such filter assemblies generally comprise at least one filter located in a filter housing. 
     During normal operation of a vacuum cleaner, dirt and dust may be deposited on a filter and, after a period of time, it could become blocked. Blockages reduce the efficiency at which a vacuum cleaner operates. Therefore, a typical filter will occasionally need to be replaced or cleaned in order to maintain the performance of the vacuum cleaner. In order to allow cleaning or replacement of the filter, it is common for such filters to be removable from a vacuum cleaner. Appliances with replaceable filters are common but the purchase of replacement filters can add to the overall cost of maintenance of the appliance. 
     Re-useable filters can reduce filter maintenance costs. U.S. Pat. No. 4,902,306, for example, discloses an air filter assembly including electrostatic filter elements and a foam filter that can be cleaned by washing. 
     Another type of known filter assembly is that used on the Dyson range of vacuum cleaners, for example, on model numbers DC04, DC07, DC12, DC14 and DC15. In these vacuum cleaners, the filter assembly essentially comprises a filter housing or filter cage, a first filter portion and a second filter portion. The filter housing has a round or rectangular cross-section and is manufactured from a suitable plastics material. The filter housing is adapted to receive the first and second filter portions. The second filter portion may be bonded to the filter housing to prevent misalignment. The first filter portion is usually washable. The second filter may also be washable and the second filter portion and the filter housing must be washed together if the second filter portion is bonded to the filter housing. After washing and after drying the filter assembly can be returned to the vacuum cleaner for further use. 
     The principle by which filter assemblies of this type operate is described in GB 2349105 and EP 1239760B. 
     SUMMARY OF THE INVENTION 
     According to the invention, there is provided a cleaning appliance comprising a main body, the main body including a motor and fan unit for generating an airflow, separating apparatus for separating dirt and dust from the airflow and a filter arranged around at least a part of the motor and fan unit, wherein the filter is removable through a side of the appliance. 
     The advantage of providing a removable filter accessible through a side of the appliance is that the user can more easily see where and how to access the filter, so the user is able to carry out servicing and maintenance procedures more quickly and easily. This also means that a filter requiring cleaning or replacement will be more readily dealt with, thus avoiding unnecessary strain or overloading on the filter which could, in turn, lead to dirt and dust passing through the filter and, in the case of a pre-motor filter, passing onto the motor and fan unit, leading to damage to motor and fan components. 
     Preferably, the filter is accessed through a hinged door in the appliance, the door including a wheel. The door may be the wheel itself. A catch may be provided for the door. 
     Preferably the filter is cylindrical and the motor and fan unit is located within the filter. This provides for a particularly compact configuration, allowing smaller, more compact appliances to be manufactured. 
     Preferably the filter surface extends around a portion or the cylindrical filter, preferably fully around the filter. This arrangement enables the maximum surface area of the filter material to be used, increasing a filter capacity and thus reducing the number of times the filter has to be cleaned. 
     In a preferred embodiment, the passageway for receiving the filter forms a scroll inlet, which provides for an incoming dirt and dust load to be spread evenly across a filter. An even spread of dirt and dust load helps to reduce localised blocking of the filter. The passageway comprises a wall and, preferably, the cross-sectional area of the passageway between the wall and the filter surface decreases in the downstream direction. An advantage of this arrangement is that the dirt and dust load is directed and channelled towards the filter medium. 
     Further advantageous features are set out in the detailed description below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the invention will now be described with reference to the accompanying drawings in which: 
         FIG. 1  is a side view of a cylinder vacuum cleaner constructed according to the invention; 
         FIG. 2  is a plan view of the cylinder vacuum cleaner of  FIG. 1 ; 
         FIG. 3  is a side section taken along the line A-A of  FIG. 2 ; 
         FIG. 4  is a perspective view of a filter assembly forming part of the vacuum cleaner of  FIG. 1 ; and 
         FIG. 5  is a perspective view of the vacuum cleaner of  FIG. 1 , showing the cyclonic separating apparatus removed from the cylinder vacuum cleaner of  FIG. 1  and showing the removal of the filter assembly of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A vacuum cleaner according to the invention is shown in  FIGS. 1 ,  2  and  3 . The vacuum cleaner  10  has a main body  12  housing a motor and fan (shown as motor and fan unit  30 ) and to which a pair of wheels  14  is attached. The wheels  14  allow the main body  12  of the vacuum cleaner  10  to be maneuvered across a floor surface. In this example, the separating apparatus  18  takes the form of a cyclonic separator. However, other arrangements, for example, a pleated filter or a bag, may be used. The nature of the separating apparatus  18  is not material to the invention. 
     A dirty air inlet  16  is formed on the main body  12 . A hose and wand assembly (not shown) can be connected to the dirty air inlet  16  in order to enable a user to clean a floor surface. 
     The interior of the cyclonic separating apparatus  100  is in communication with the dirty air inlet  16  through which a dirt-laden airflow enters the cyclonic separating apparatus  100 . The cyclonic separating apparatus  100  can be removed from the main body  12  for emptying purposes. 
     The cyclonic separating apparatus  100  comprises a substantially cylindrical outer wall  102 . The outer wall  102  defines part of a cyclonic separator system  104  and a collector  106 . Dirt and dust is both separated by the cyclonic separator system  104  and collected in the collector  106  in this region. An inlet  108  is formed in the outer wall  102 . The inlet  108  forms a communication path between the dirty air inlet  16  and the interior of the cyclonic separator  104 . The air inlet  108  is arranged tangentially to the cyclonic separator  104  so that the incoming air is forced to follow a helical path around the interior of the outer wall  102 . 
     The air outlets  110  of the cyclonic separator system  104  are in communication with an outlet  112 . The outlet  112  provides an airflow path from the cyclonic separating apparatus  100  into other parts of the vacuum cleaner  10 . Located downstream of the outlet  112  is pre-motor filter  20 , the motor and fan unit  30  and a post-motor filter  40 . The passageway  114  and outer wall  116  are arranged to form a scroll shaped inlet to the filter  20  and the pre-motor filter  20  is located in passageway  114 , arranged to lie on the horizontal x axis of  FIG. 2 . The cross-sectional area of the passageway  114  between the wall  116  and the filter surface  22  decreases in the downstream direction. 
     Referring now to  FIGS. 4 and 5 , the pre-motor filter assembly  20  essentially comprises a cylindrical sleeve  21  of filter material  120  delimited by first  121  and second  122  rim portions. The rim portions  121 ,  122  are arranged to encapsulate the filter material  120 . Rim  121  comprises a first annular ring  123  and rim edge  124 . The annular ring  123  is arranged to overlap an area of the edge of the filter material  120  to clamp or fix the filter material in place. Rim edge  124  is provided to aid placement and location of the filter in the passageway  114  of the appliance. Rim  122  comprises second  125  and third  126  annular rings and a rim edge  127 . Annular ring  126  has a diameter greater than annular rig  125 . Rim edge  127  has a diameter greater than annular rig  126 . Cylindrical outer walls  128  and  129  of respective annular rings  125 ,  126  are arranged to provide location and support for the filter assembly in the body of the appliance. The rim edge  127  is arranged to overlap an area of the edge of the filter material  120  to clamp or fix the filter material in place. 
     The rims  121  and  122  are manufactured from a plastics material of suitable hardness, durability and strength to be mounted securely in the appliance around the motor and fan unit  30 . A suitable material from which the rims  121  and  122  can be manufactured is polyurethane with a hardness of between 20 and 90 Duro measured on the Shore A Rockwell scale. 
     In the preferred embodiment the filter material  120  is pleated. A pleated configuration, shown in section as a saw tooth arrangement in  FIG. 3 , provides a large surface area for filtration. Any suitable filter material, or combination of material layers may be used, such as electrostatic filter material, HEPA (High Efficiency Particulate Arrest) material, a non woven filter medium such as fleece or a mesh. The filter material or layers(s) are held together in a known manner by stitching or other sealing means. 
     A tab  130  or shaped portion may be provided on the filter assembly to assist with the removal of the filter assembly  20  from the passageway  114  in the main body  12  of the appliance  10 . 
     Referring to  FIG. 5 , a shaped or recessed portion  115  comprising the passageway  114 , is arranged to accommodate filter assembly  20 . Portion  115  includes the accommodation around the motor and fan unit  30  in the main body  12 . A side portion  150  of the of the main body  12  is arranged to move from a retracted position, proximate the main body  12  and motor unit  30 , to an extended position away from the main body  12  and exposing an opening  152  to the recessed portion  115 . The side portion  150  includes a door  151  maintained in an attached state to the main body  12  by a hinge  142 . The door  151  includes a wheel  140  mounted on and around the outer surface of side portion  150  and a fastening means  155  arranged to engage with a corresponding fastening means on the main body  12  in order to secure the door  151  closed during use of the vacuum cleaner  10 . In a preferred embodiment the fastening means  155  is easily accessible for a user, and comprises a quarter-turn screw that twists to release and can be operated with a simple tool such as the edge of a coin. The inner surface of the door  151  includes a shaped region adapted and arranged to abut the rim  122  of the filter assembly  20  in order to locate the filter assembly  20  correctly within the main body  12 . 
     The features of the rim  122  and the inner surface of the door  151  or the side portion  150  can be used in conjunction with the vacuum cleaner  10  in order to prevent the user from inadvertently positioning the filter assembly  20  in the vacuum cleaner  10  in an incorrect position or orientation or attempting to operate the vacuum cleaner with the filter assembly  20  in an incorrect position. The rim  122  and surface are dimensioned and arranged such that they are able to co operate with a portion of the vacuum cleaner. For example the door  151  may be prevented from closing or a microswitch controlling the power to the motor may not be actuated unless the filter assembly is mounted in the vacuum cleaner correctly. 
     In use, the motor and fan unit  30  draws a flow of dirt-laden air through the hose and wand, into the dirty air inlet  16 , through the inlet  108  and into the cyclonic separating apparatus  100 . 
     Cleaned air then flows back through the cyclonic separator system  104 , exits through the air outlets  110  and enters the outlet  112 . The cleaned air then passes from the outlet  112  sequentially through the pre-motor filter  20 , the motor and fan unit  30 , and the post-motor filter  40  before being exhausted from the vacuum cleaner  10  through air vents  50  located on the outer surface of the vacuum cleaner  10 . 
     When a cleaning operation is finished, the collector  106  of the cyclonic separating apparatus  100  may be full of dirt and dust, and require emptying. To do this, the user switches off the vacuum cleaner  10 . The user releases the cyclonic separating apparatus  100  from the main body  12  by pressing a release button (not shown), removes the cyclonic separating apparatus  100  from the remainder of the vacuum cleaner  10  and places it over a suitable receptacle such as a dustbin. The user then presses a further release button (not shown) in order to release the catch  15 . The dirt and dust collected in the collector(s)  106  can thus be emptied conveniently and efficiently. 
     When the cyclonic separating apparatus  100  has been emptied as described above, the user manually moves the closure member  15   a  back into the closed position shown in  FIGS. 1 and 3 . After an operation such as this emptying of the collector  106  of the cyclonic separating apparatus  100 . The cyclonic separating apparatus  100  can be replaced on the main body  12  of the vacuum cleaner  10  (as shown in  FIGS. 1 and 2 ) for further cleaning operations. 
     Through use, the filter assembly  20  and filter material  120  will become clogged with dust or dirt. Continued use would lead to a restriction in the airflow through the filter assembly  20 . This causes a reduction in the filtration efficiency. In order to alleviate this, the filter assembly  20  must be replaced or washed. To do this, the user switches off the vacuum cleaner  10 . In the preferred embodiment the filter material and assembly  20  are capable of being cleaned by washing. The filter assembly  20  is removed from the vacuum cleaner main body  12  through the door  151 . The door is released from its secured, closed position by the release, by the user, of fastening  155 . Once the user has obtained access to the recess  115  accommodating the filter assembly  20  the filter assembly is removed by the user gripping the tabs  130  and pulling the tab  130  outwardly from the housing, towards the user along axis X-X of  FIG. 2 . In this way, the user does not have to handle the clogged filter assembly  20  directly. This makes replacing or cleaning the filter assembly  20  a more hygienic task. The filter assembly  20  is washed by rinsing under a household tap in a known manner and allowed to dry. The filter assembly  10  is then re-inserted into the main body  12  and housing recess  115  of the appliance or vacuum cleaner  10 , and operation can continue. 
     The invention is not limited to the detailed description given above. Variations will be apparent to the person skilled in the art. For example, a part of the cyclonic separating apparatus other than the wheel may comprise a door and may be movable for filter cleaning purposes. For example, the side or top of the cyclonic separating apparatus may be movable (or openable). Other opening arrangements for the door member may be used; for example, sliding, retracting or rotating door members. Other forms, arrangements and locations of fastener members for a door may be used, for example screws, bolts or resealable or glue fastenings. 
     The invention has been described in relation to a pre-motor filter, but could of course be implemented for a post-motor filter. In appliances incorporating a pre-motor filter and a post-motor filter, both filters could be removable through a side of the appliance. The filters could be removable through the same side of the appliance, or different sides. In the case of the filters being removable through the same side of the appliance, there may be provided a common door for the filters, or separate doors for each filter. 
     Additionally, the filter assembly need not be cylindrical. Other arrangements, for example, oval, annular, square, rectangular or cuboid shapes could be used. Other filter materials and construction may be used, for example a mesh, non-pleated material, electrostatic layers. Other materials may be used for the assembly e.g. plastics, PE etc. 
     The filter assembly may be located in the main body using other means, for example by a push or friction fit. The cleaning appliance need not be a cylinder vacuum cleaner. The invention is applicable to other types of vacuum cleaner, for example, upright machines, stick-vacuums or hand-held cleaners. Further, the present invention is applicable to other types of cleaning appliances, for example, a wet and dry machine or a carpet shampooer.