Abstract:
The invention provides a vacuum cleaner ( 10 ) comprising dirt and dust separating apparatus ( 52 ) for separating dirt and dust from an airflow and having an inlet ( 59 ), and a cleaner head ( 22 ) having an outlet ( 32 ) communicating with the inlet ( 59 ) of the dirt and dust separating apparatus ( 52 ). The dirt and dust separating apparatus ( 52 ), or a part ( 58 ) thereof incorporating the inlet ( 59 ), is movable into an alternative position in which the outlet ( 32 ) of the cleaner head ( 22 ) is not in communication with the inlet ( 59 ) of the dirt and dust separating apparatus ( 52 ) and in which an alternative dirty air inlet ( 100 ) may be connected to the inlet ( 59 ) of the dirt and dust separating apparatus ( 52 ) characterized in that the inlet ( 59 ) of the dirt and dust separating apparatus ( 52 ) is adapted to cooperate releasably with the outlet ( 32 ) of the cleaner head ( 22 ). This arrangement allows a hose ( 100 ), or a hose and wand assembly, to be attached directly to the inlet ( 59 ) to the dirt and dust separating apparatus ( 52 ). When the cleaner head ( 22 ) is in use, the incoming air is not required to travel through the hose ( 100 ) or any other ducting designed to carry air from the hose ( 100 ). In each case, the airflow path is kept to an absolute minimum. Furthermore, there is no changeover valve involved which reduces the risk of malfunction or failure in this area and also avoids the need for the incoming air to pass through a discontinuity in the airflow path of the cleaner ( 10 ).

Description:
FIELD OF THE INVENTION 
     The invention relates to a vacuum cleaner particularly, but not exclusively, to a robotic vacuum cleaner. 
     BACKGROUND OF THE INVENTION 
     Vacuum cleaners operable in more than one mode, i.e., in upright mode and in cylinder mode, are well known. In the upright mode, the cleaner operates by drawing dirty air into the cleaner by way of a cleaner head which travels across the floor or other surface to be cleaned. In the cylinder mode, the dirty air is drawn into the cleaner via a hose or a hose and wand assembly. Most cleaners which are convertible between the two modes of operation are essentially upright cleaners which have permanently attached hoses which can be brought into operation when cylinder cleaning is required. In some cases, the hose is permanently connected to the inlet of the dirt and dust separating apparatus of the cleaner and the distal end of the hose is then stored in a hollow socket during upright cleaning so that the hose becomes part of the dirty air inlet path during upright cleaning. Such an arrangement results in losses which are higher than is desirable during upright cleaning due to the passage of the air through a hose rather than through a smooth conduit or pipe. In other arrangements, the hose is permanently connected to the main body of the cleaner but a valve is used to select whether dirty air is drawn into the cleaner through the cleaner head or through the hose. The operation of the valve can be made dependent upon the angle of inclination of the main body of the upright cleaner as illustrated and described in EP 0 134 654 B. This type of arrangement is better than the aforementioned alternative arrangement during upright cleaning because the dirty air is not required to pass through a hose. However, in such an arrangement, the airflow passage is often longer than is desirable during cylinder cleaning and, as a result, avoidable losses can occur. 
     Autonomous or robotic vacuum cleaners have also been proposed. Robotic vacuum cleaners operate in a manner which is different to that of both upright and cylinder cleaners. In the normal or autonomous mode of operation, the cleaner traverses the surface to be cleaned under its own power and using its own navigation system so that human intervention is not required. Dirty air is drawn into the machine through a cleaner head in a manner similar to that used in upright cleaning using an upright cleaner. Robotic vacuum cleaners are shown and described in, inter alia, U.S. Pat. No. 5,781,960 and U.S. Pat. No. 5,109,566. The latter of these documents also indicates that a hose can be attached to the robotic vacuum cleaner for the purpose of attaching a conventional suction hose for manual cleaning of areas which cannot be reached by the robotic cleaner. As in conventional vacuum cleaners, a device for changing the air path so as to select the dirty air inlet for the desired mode of operation is included. Such changeover devices are inevitably prone to failure on occasion and normally cause a discontinuity in the airflow paths in which they are placed. This can lead to frictional losses and/or pressure drops within the relevant cleaner. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a vacuum cleaner which is convertible between two different modes of operation easily and conveniently. It is a further object of the present invention to provide a vacuum cleaner which is convertible between two different modes of operation in a manner which avoids unnecessary losses or in which unnecessary losses are minimised. 
     An aspect of the invention provides a vacuum cleaner comprising a chassis for releasably supporting a dirt and dust separating apparatus for separating dirt and dust from an airflow, and a cleaner head having an outlet communicating releasably with an inlet of the dirt and dust separating apparatus, the dirt and dust separating apparatus being releasable from the chassis to allow the dirt and dust separating apparatus, or a part thereof incorporating the inlet to move into an alternative position in which the outlet of the cleaner head is not in communication with the inlet of the dirt and dust separating apparatus and in which an alternative dirty air inlet may be connected to the inlet of the dirt and dust separating apparatus. 
     This arrangement allows a hose, or a hose and wand assembly, to be attached directly to the inlet to the dirt and dust separating apparatus without forcing the incoming air which then enters via the hose to travel through the ducting designed to carry dirty air from the cleaner head. When the cleaner head is in use, the incoming air is not forced to travel through the hose or any other ducting designed to carry air from the hose. In each case, the airflow path is kept to an absolute minimum. Furthermore, there is no changeover valve involved which us the risk of malfunction or failure in this area and also avoids the need for the incoming air to pass through a discontinuity in the airflow path of the cleaner. 
     In a preferred embodiment, the dirt and dust separating apparatus comprises, or is surrounded by, a rigid shell or housing. This makes the movement of the apparatus, or the relevant part thereof, easier and more manageable for the user. More preferably, the dirt and dust separating apparatus is generally cylindrical, with one end portion being attachable to a main body in more than one position relative thereto, advantageously in two diametrically opposed positions. The diametric opposition of the two said positions is advantageous because the risk of the wrong position being inadvertently selected by the user is minimised. Other spacings of the two said positions are possible, a spacing of 90° being advantageous as well. As an alternative to removing the part of the separating apparatus incorporating the inlet and reattaching it in a new position, the part of the separating apparatus incorporating the inlet can be rotatable with respect to the remainder of the separating apparatus. Suitable indicia or physical formations can be used to mark the positions between which the part of the separating apparatus incorporating the inlet should be rotated 
     It is preferred that the dirt and dust separating apparatus comprises a centrifugal separator, more preferably two cyclones arranged in series. Such an arrangement provides efficient and effective separation of dirt and dust from the airflow. 
     Preferably the vacuum cleaner comprises means for sensing the position of the dirt and dust separating apparatus, or the part incorporating the inlet, and for controlling operation of the cleaner according to the sensed position. When the cleaner is an autonomous cleaner which is capable of autonomously moving across an area, the sensed position of the inlet can control whether the cleaner operates in an autonomous mode or a manual mode. 
     Preferably, when the sensing means senses that the outlet of the cleaner head is not in communication with the inlet of the dirt and dust separating apparatus, operation of the brush bar of the cleaner is inhibited. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein: 
     FIG. 1 is a perspective view of a vacuum cleaner according to the invention; 
     FIG. 2 is an underneath view of the vacuum cleaner of FIG. 1; 
     FIG. 3 is a sectional view through the vacuum cleaner of FIG. 1 taken along the line III—III of FIG. 2; 
     FIG. 4 a  is a transverse sectional view through part of the cleaner of FIG. 1 showing the separating apparatus in a first position; 
     FIG. 4 b  is a transverse sectional view through part of the cleaner of FIG. 1 showing the separating apparatus in a second position; 
     FIG. 4 c  shows labels of different reflectivities used on end portions of the cleaner of FIG. 1; 
     FIG. 5 a  is a longitudinal sectional view through part of the cleaner of FIG. 1 showing the separating apparatus connected to the chassis; 
     FIG. 5 b  is a longitudinal sectional view through part of the cleaner of FIG. 1 showing the separating apparatus being released from the chassis; 
     FIGS. 6 a  and  6   b  are similar transverse sectional views to FIGS. 4 a  and  4   b  showing an alternative form of sensing the position of the inlet to that shown in FIGS. 4 a  and  4   b;    
     FIG. 6 c  is a more detailed view of the sensing arrangement shown in FIGS. 6 a  and  6   b;    
     FIG. 7 is a block diagram of a control system for the cleaner of FIG. 1; 
     FIG. 8 is a flow diagram of a method of operating the cleaner which can be performed by the control system of FIG. 7; and 
     FIG. 9 is a block diagram of an arrangement for controlling operation of the cleaner head according to whether the cleaner head or an alternative dirty air inlet is being used. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The vacuum cleaner  10  shown in the drawings has a supporting chassis  12  which is generally circular in shape and is supported on two driven wheels  14  and a castor wheel  16 . The chassis  12  is preferably manufactured from high-strength moulded plastics material, such as ABS, but can equally be made from metal such as aluminium or steel. The chassis  12  provides support for the components of the cleaner  10  which will be described below. The driven wheels  14  are arranged at either end of a diameter of the chassis  12 , the diameter lying perpendicular to the longitudinal axis  18  of the cleaner  10 . Each driven wheel  14  is moulded from a high-strength plastics material and carries a comparatively soft, ridged band around its circumference to enhance the grip of the wheel  14  when the cleaner  10  is traversing a smooth floor. The driven wheels  14  are mounted independently of one another via support bearings (not shown) and each driven wheel  14  is connected directly to a motor  15  which is capable of driving the respective wheel  14  in either a forward direction or a reverse direction. By driving both wheels  14  forward at the same speed, the cleaner  10  can be driven in a forward direction. By driving both wheels  14  in a reverse direction at the same speed, the cleaner  10  can be driven in a backward direction. By driving the wheels  14  in opposite directions, the cleaner  10  can be made to rotate about its own central axis so as to effect a turning manoeuvre. The aforementioned method of driving a vehicle is well known and will not therefore be described any further here. 
     The castor wheel  16  is significantly smaller in diameter than the driven wheels  14  as can be seen from, for example, FIG.  3 . The castor wheel  16  is not driven and merely serves to support the chassis  12  at the rear of the cleaner  10 . The location of the castor wheel  16  at the trailing edge of the chassis  12 , and the fact that the castor wheel  16  is swivellingly mounted on the chassis by means of a swivel joint  20 , allows the castor wheel  16  to trail behind the cleaner  10  in a manner which does not hinder the manoeuvrability of the cleaner  10  whilst it is being driven by way of the driven wheels  14 . The swivel joint  20  is most clearly shown in FIG.  3 . The castor wheel  16  is fixedly attached to an upwardly extending cylindrical member  20   a  which is received by an annular housing  20   b  to allow free rotational movement of the cylindrical member  20   a  therewithin. This type of arrangement is well known. The castor wheel  16  can be made from a moulded plastics material or can be formed from another synthetic material such as Nylon. 
     Mounted on the underside of the chassis  12  is a cleaner head  22  which includes a suction opening  24  facing the surface on which the cleaner  10  is supported. The suction opening  24  is essentially rectangular and extends across the majority of the width of the cleaner head  22 . A brush bar  26  is rotatably mounted in the suction opening  24  and a motor  28  is mounted on the cleaner head  22  for driving the brush bar  26  by way of a drive belt (not shown) extending between a shaft of the motor  28  and the brush bar  26 . The cleaner head  22  is mounted on the chassis  12  in such a way that the cleaner head  22  is able to float on the surface to be cleaned. This is achieved in this embodiment in that the cleaner head  22  is pivotally connected to an arm  27  about a first pivot  29   a  (see FIG. 5) which in turn is pivotally connected to the underside of the chassis  12  about a second pivot  29   b  (chassis  12  is not shown in FIG. 5 for the sake of clarity). The double articulation of the connection between the cleaner head  22  and the chassis  12  allows the cleaner head  22  to move freely in a vertical direction with respect to the chassis  12 . This enables the cleaner head  22  to climb over small obstacles such as books, magazines, rug edges, etc. Obstacles of up to approximately 25 mm in height can be traversed in this way. A flexible connection  30  (see FIGS. 4 and 5) is located between a rear portion of the cleaner head  22  and an inlet port  32  located in the chassis  12 . The flexible connection  30  consists of a rolling seal, one end of which is sealingly attached to the upstream mouth of the inlet port  32  and the other end of which is sealingly attached to the periphery of an aperture in the cleaner head  22 . When the cleaner head  22  moves upwardly with respect to the chassis  12 , the rolling seal  30  distorts or crumples to accommodate the upward movement of the cleaner head  22 . When the cleaner head  22  moves downwardly with respect to the chassis  12 , the rolling seal  30  unfolds or extends into an extended position to accommodate the downward movement. 
     In order to assist the cleaner head  22  to move vertically upwards when an obstacle is encountered, forwardly projecting ramps  36  are provided at the front edge of the cleaner head  22 . In the event that an obstacle is encountered, the obstacle will initially abut against the ramps  36  and the inclination of the ramps will then lift the cleaner head  22  over the obstacle in question so as to avoid the cleaner  10  from becoming lodged against the obstacle. The cleaner head  22  is shown in a lowered position in FIGS. 3 and 5. The castor wheel  16  also includes a ramped portion  17  which provides additional assistance when the cleaner  10  encounters an obstacle and is required to climb over it. In this way, the castor wheel  16  will not become lodged against the obstacle after the cleaner head  22  has climbed over it. 
     As can be seen from FIG. 2, the cleaner head  22  is asymmetrically mounted on the chassis  12  so that one side of the cleaner head  22  protrudes beyond the general circumference of the chassis  12 . This allows the cleaner  10  to clean up to the edge of a room on the side of the cleaner  10  on which the cleaner head  22  protrudes. 
     The chassis  12  carries a plurality of sensors  40  which are designed and arranged to detect obstacles in the path of the cleaner  10  and its proximity to, for example, a wall or other boundary such as a piece of furniture. The sensors  40  comprise several ultra-sonic sensors and several infra-red sensors. The array illustrated in FIG. 1 is not intended to be limitative and the arrangement of the sensors does not form part of the present invention. Suffice it to say that the vacuum cleaner  10  carries sufficient sensors and detectors  40  to enable the cleaner  10  to guide itself or to be guided around a predefined area so that the said area can be cleaned. Control software, comprising navigation controls and steering devices, is housed within a housing  42  located beneath a control panel  44  or elsewhere within the cleaner  10 . Battery packs  46  are mounted on the chassis  12  inwardly of the driven wheels  14  to provide power to the motors for driving the wheels  14  and to the control software. The battery packs  46  are removable to allow them to be transferred to a battery charger (not shown). The vacuum cleaner  10  also includes a motor and fan unit  50  supported on the chassis  12  for drawing dirty air into the vacuum cleaner  10  via the suction opening  24  in the cleaner head  22 . 
     The chassis  12  also carries a cyclonic separator  52  for separating dirt and dust from the air drawn into the cleaner  10 . The features of the cyclonic separator  52  are best seen from FIGS. 3 and 4. The cyclonic separator  52  comprises an outer cyclone  54  and an inner cyclone  56  arranged concentrically therewith, both cyclones  54 ,  56  having their coaxial axes lying horizontally. The cyclonic separator  52  comprises an end portion  58  which has a tangential inlet  59 . The tangential inlet  59  has a mouth at the distal end thereof. The mouth is generally circular in shape, but is somewhat flattened along one edge to give the mouth a vaguely D-shaped section. The end portion  58  is otherwise generally cylindrical and has an end wall  60  which is generally helical. The end portion  58  opens directly into a cylindrical bin  62  having an outer wall  64  whose diameter is the same as that of the end portion  58 . The end portion  58  and the cylindrical bin  62  are held together or joined by way of a releasable clip which can be of any known design. No specific clip is shown in the drawings. A lip seal is provided between the cylindrical bin  62  and the end portion  52  in order to maintain a good seal between the respective parts. The cylindrical bin  62  is made from a transparent plastics material to allow a user to view the interior of the outer cyclone  54 . The end of the bin  62  remote from the end portion  58  is frusto-conical in shape and closed. A locating ring  66  is formed integrally with the end of the bin at a distance from the outer wall  64  thereof and a dust ring  68  is also formed integrally with the end of the  62  inwardly of the locating ring  66 . Located on the outer surface of the bin  62  are two opposed gripper portions  70  which are adapted to assist a user to remove the separator  52  from the chassis  12  for emptying purposes. Specifically, the gripper portions  70  are moulded integrally with the transparent bin  62  and extend upwardly and outwardly from the outer wall  64  so as to form an undercut profile as shown in FIG.  1 . 
     The inner cyclone  56  is formed by a partially-cylindrical, partially-frusto-conical cyclone body  72  which is rigidly attached to the end face of the end portion  58 . The cyclone body  72  lies along the longitudinal axis of the transparent bin  62  and extends almost to the end face thereof so that the distal end  72   a  of the cyclone body  72  is surrounded by the dust ring  68 . The gap between the cone opening at the distal end  72   a  of the cyclone body  72  and the end face of the bin  62  is preferably less than 8 mm. 
     A fine dust collector  74  is located in the bin  62  and is supported by the locating ring  66  at one end thereof. The fine dust collector  74  is supported at the other end thereof by the cyclone body  72 . Seals  76  are provided between the fine dust collector  74  and the respective support at either end. The fine dust collector  74  has a first cylindrical portion  74   a  adapted to be received within the locating ring  66 , and a second cylindrical portion  74   b  having a smaller diameter than the first cylindrical portion  74   a . The cylindrical portions  74   a ,  74   b  are joined by a frusto-conical portion  74   c  which is integrally moulded therewith. A single fin or baffle  78  is also moulded integrally with the fine dust collector  74  and extends radially outwardly from the second cylindrical portion  74   b  and from the frusto-conical portion  74   c . The outer edge of the fin  78  is aligned with the first cylindrical portion  74   a  and the edge of the fin  78  remote from the first cylindrical portion  74   a  is essentially parallel to the frusto-conical portion  74   c . The fin  78  extends vertically upwardly from the fine dust collector  74 . 
     A shroud  80  is located between the first and second cyclones  54 ,  56 . The shroud  80  is cylindrical in shape and is supported at one end by the end portion  58  and by the cyclone body  72  of the inner cyclone  56  at the other end. As is known, the shroud  80  has perforations  82  extending therethrough and a lip  83  projecting from the end of the shroud  80  remote from the end portion  58 . A channel  84  is formed between the shroud  80  and the outer surface of the cyclone body  72 , which channel  84  communicates with an inlet port  86  leading to the interior of the inner cyclone  56  in a manner which encourages the incoming airflow to adopt a swirling, helical path. This is achieved by means of a tangential or scroll entry into the inner cyclone  56  as can be seen from FIG. 4. A vortex finder (not shown) is mounted on the housing of the motor and fan unit  50  and extends into the second cyclone  56  through an aperture in the end wall  60  of the end portion  58 . The vortex finder is located centrally of the larger end of the inner cyclone  56  to conduct air out of the cyclonic separator  52  after separation has taken place. It also helps to secure the cyclonic separator  52  in position on the chassis  12 . 
     The exiting air is conducted past the motor and fan unit  50  so that the motor can be cooled before the air is expelled to atmosphere. Additionally, a post-motor filter (not shown) can be provided downstream of the motor and fan unit  50  in order to further minimise the risk of emissions into the atmosphere from the vacuum cleaner  10 . 
     The entire cyclonic separator  52  is releasable from the chassis  12 . A seal arm  90  is pivotally mounted about a pivot point  92  on the chassis  12 . The seal arm  90  carries the inlet port  32  which, as described above, communicates with the cleaner head  22  by means of the rolling seal  30 . The seal arm  90  is biased into an upward position (i.e., in a counterclockwise direction as seen in FIGS. 5 a  and  5   b ) by means of a spring (not shown) acting between a seat  94  of the seal arm  90  and a fixed part of the chassis  12 . When the cyclonic separator  52  is located in the position shown in FIG. 5 a , the inlet port  32  is pressed against the mouth of the tangential inlet  59  of the end portion  58  to form a seal therewith so that air can flow from the cleaner head  22  directly into the outer cyclone  54 . A hooked catch  96  is provided on the seal arm  90  adjacent the inlet port  32  and on the side thereof remote from the motor and fan unit  50 . The cyclonic separator  52  is held in position by means of the hooked catch  96  (in conjunction with the location of the vortex finder in the aperture in the end wall of the end portion) when the cleaner  10  is in use, as shown in FIG. 5 a . A button  34  located in the control panel  44  is connected by a rod (not shown) to the seal arm  90  so that pressing the button  34  causes the seal arm  90  to move in a clockwise direction (as seen in FIG. 5) against the bias of the spring. The hooked catch  96  is then released from the mouth of the tangential inlet  59  so that the cyclonic separator  52  can be lifted away from the chassis  12  by means of the gripper portions  70 . The bag  62  can then be released from the end portion  58  (which carries with it the shroud  80  and the inner cyclone body  72 ) to facilitate the emptying thereof. 
     When the bin  62  is released from the end portion  58 , the user has the option to replace the two parts together in a different configuration. Instead of locating the end portion  58  on the bin  62  so at the tangential inlet  59  extends downwardly towards the inlet port  32 , the end portion  58  can be turned through 180° so that the tangential inlet  59  extends vertically upwardly. The two positions of the end portion  58  with respect to the bin  62  are diametrically opposed. Shapings (not shown) can be moulded into the bin  62  and end portion  58  in order to avoid the relevant pars being joined together in other configurations. The execution of the rotation of the end portion  58  with respect to the bin  62  is easily carried out by first separating the two parts, re-orienting them and then joining them in the appropriate manner. 
     When the end portion  58  has been rotated with respect to the bin  62  as described above, the tangential inlet  59  will then extend vertically upwardly. This exposes the tangential inlet  59  as shown in FIG. 4 b  so that a hose or a hose and wand assembly can be attached directly to the tangential inlet  59 . The hose  100  has a connector  102  which comprises a tubular conduit  104  which is dimensioned so as to fit snugly inside the tangential inlet  59 , and a flange  106  which extends outwardly from the conduit  104 . The flange  106  carries a seal  107  which, when the connector  102  is introduced to the tangential inlet  59 , abuts against the mouth of the tangential inlet  59 . When the hose  100  is fitted to the tangential inlet  59 , the operation of the motor and fan unit  50  draws air into the cleaner  10  via the hose  100  instead of via the cleaner head  22 . The hose or hose and wand assembly can then be used to clean areas of the carpet or other surface to be cleaned which cannot be reached by the cleaner when it is operating in a robotic mode; for example, when small or narrow areas need to be accessed. 
     The vacuum cleaner  10  described above operates in the following manner in a robotic mode. In order for the cleaner  10  to traverse the area to be cleaned, the wheels  14  are driven by the motors  15  which, in turn, are powered by the batteries  46 . The direction of movement of the cleaner  10  is determined by the control software which communicates with the sensors  40  which are designed to detect any obstacles in the path of the cleaner  10  so as to navigate the cleaner  10  around the area to be cleaned. Methodologies and control systems for navigating a robotic vacuum cleaner around a room or other area are well documented elsewhere and do not form part of the inventive concept of this invention. Any of the known methodologies or systems could be implemented here to provide a suitable navigation system. 
     The batteries  46  also provide power to operate the motor and fan unit  50  to draw air into the cleaner  10  via the suction opening  24  in the cleaner head  22 . The end portion  58  is orientated so that the tangential inlet  59  to the outer cyclone  56  communicates with the cleaner head  22 . The motor  28  is also driven by the batteries  46  so that the brush bar  26  is rotated in order to achieve good pick-up, particularly when the cleaner  10  is to be used to clean a carpet. The dirty air is drawn into the cleaner head  22  and conducted to the cyclonic separator  52  via the telescopic conduit  30  and the inlet port  32 . The dirty air then enters the end portion  58  in a tangential manner and adopts a helical path by virtue of the shape of the end wall  60 . The air then spirals down the interior of the outer wall  64  of the bin  62  during which motion any relatively large dirt and fluff particles are separated from the airflow. The separated dirt and fluff particles collect in the end of the bin  62  remote from the end portion  58 . The fin  78  discourages uneven accumulation of dirt and fluff particles and helps to distribute the dirt and fluff collected around the end of the bin  62  in a relatively even manner. 
     The airflow from which dirt and larger fluff particles has been separated moves inwardly away from the outer wall  64  of the bin  62  and travels back along the exterior wall of the fine dust collector  74  towards the shroud  80 . The presence of the shroud  80  also helps to prevent larger particles and fluff traveling from the outer cyclone  54  into the inner cyclone  56 , as is known. The air from which comparatively large particles and dirt has been separated then passes through the shroud  80  and travels along the channel between the shroud  80  and the outer surface of the inner cyclone body  72  until it reaches the inlet port  86  to the inner cyclone  56 . The air then enters the inner cyclone  56  in a helical manner and follows a spiral path around the inner surface of the cyclone body  72 . Because of the frusto-conical shape of the cyclone body  72 , the speed of the airflow increases to very high values at which the fine dirt and dust still entrained within the airflow is separated therefrom. The fine dirt and dust separated in the inner cyclone  56  is collected in the fine dust collector  74  outwardly of the dust ring  68 . The dust ring  68  discourages re-entrainment of the separated dirt and dust back into the airflow. 
     When the fine dirt and dust has been separated from the airflow, the cleaned air exits the cyclonic separator via the vortex finder (not shown). The air is passed over or around the motor and fan unit  50  in order to cool the motor before it is expelled into the atmosphere. When a hose or hose and wand assembly is to be used to clean other areas, the cyclonic separator  52  is released from the chassis  12  and the end portion  58  is moved to the orientation in which the tangential inlet  59  is exposed so that the hose  100  can be attached. The cyclonic separator is then replaced on the chassis  12  and the hose is attached to the inlet  59 . The motor and fan unit  50  is then switched on and cleaning recommences. The cyclonic separator  52  is also released from the chassis  12  when the bin  62  requires to be emptied. 
     A user rotates the end portion  58 , and thereby the tangential inlet  59 , into the appropriate position, depending on whether they wish cleaning to be achieved by the cleaner head  22  (auto mode) or manually by a hose  100  (hose mode). The cleaner automatically senses the position of the tangential inlet  59  and responds according to the sensed position. There are a variety of ways in which the position of the end portion  58  can be sensed. Referring again to FIGS. 4 a  and  4   b , these show an optical sensing arrangement comprising an optical source, such as an infra-red source, and detector  112  mounted on the chassis of the cleaner compartment that underlies the end portion  58 . This can also be seen in FIG.  3 . The end portion  58  carries two labels  110 ,  111 . The labels are mounted on the outer face of end portion  58  at positions such that they lie directly opposite the sensor  112  when the end portion has been properly inserted into the cleaner in either its auto mode position or hose mode position. The sensing arrangement works by illuminating the label  110 , 111  with the optical source  112  and sensing light reflected from the label  110 , 111 . The labels are shown in FIG. 4 c . Each of the labels  110 , 111  carries two portions of differing reflectivity; label  110  has a black (low reflectivity) portion  113  and a silver (high reflectivity) portion  114 . Other colours could of course be used. Label  110  is mounted on the end portion  58  so that the order of black/silver portions  113 , 114  is reversed with respect to the black/silver portions  115 , 116  on label  111 . Sensor  112  is arranged to monitor light reflected from one half of the label and therefore, due to the different ordering of the black/silver label portions, will receive differing amounts of light depending on whether label  110  or label  111  is adjacent the sensor  112  and provides an electrical signal to the control system of the cleaner. 
     FIGS. 6 a - 6   c  show an alternative arrangement for sensing, the position of end portion  58 . Here, the position of the end portion  58  is sensed mechanically. Instead of the labels  110 , 111  and optical sensor  112 , a microswitch  120  is mounted on the chassis  12  of the cleaner adjacent where locating ribs of the end portion  58  lie. Two locating ribs  121 , 122  on the outer face of end portion  58  are diferently formed: rib  121  (seen more clearly in FIG. 6 c ) is solid whereas rib  122  has an indentation. When the end portion is fitted to the cleaner chassis, solid rib  121  causes operating member  123  of microswitch  120  to remain retracted within the switch casing, whereas indented rib  122  allows operating member  123  to project in to the indentation. The microswitch  120  responds differently under these two situations, and provides an electrical signal to the control system of the cleaner. It will be appreciated that the microswitch can be mounted in other positions and can respond to other mechanical features of the end portion  58 . For example, it may be preferable to have the indentation part-way along the longitudinal axis of locating rib  122 , i.e. directed into the paper in FIGS. 6 a  and  6   b.    
     As a further alternative to the optical or mechanical sensing arrangements described, an electrical sensing arrangement can be used. A conductive strip is placed on one side of the end portion  58 , in place of the reflective label  110 , and a pair of contacts are located on the chassis  12  in place of the optical sensor  112 . In one position of the end portion  58 , the contacts will be electrically coupled by the conductive strip so that a current can flow between the contacts, and in the other position of the end portion  58  the contacts will be separated by the electrically insulating plastic casing of the end portion  58  so that a current cannot flow. 
     FIG. 7 shows part of the control system for the cleaner. A central processor  140 , such as a Hitachi H8/3334 microprocessor, is connected to a user interface board  135 . A user can control the cleaner using switches  130 , 131 , 132 , which generate inputs to the processor  140 , and the processor  140  generates output signals for illuminating lights  133  to signal warning conditions and the mode of operation to the user. Processor  140  also receives inputs from sensors  19 ,  40  which are used for navigation and from sensor  112 , 120  which senses the position of the inlet  59 . Processor  140  also generates control signal outputs for controlling parts of the cleaner. For simplicity, only the control signals that are relevant to this application are shown. 
     The user controls the cleaner  10  through interaction with the control switches  130 ,  131  and  132 . Switch  130  is a global ON/OFF switch which interacts directly with the processor  140 . Setting the switch  130  to ON activates the processor  140  which then executes a power up sequence. Switches  131  select slow or fast forward operation for the autonomous mode of the cleaner, and switch  132  is a go/pause button. 
     FIG. 8 shows a method performed by control processor  140  to control operation of the cleaner. When a user presses the ON/OFF switch  130 , the control processor  140  monitors the output of the end portion  58  sensor, which will be the optical sensor  112  or microswitch  120 . The control processor compares the monitored output of the sensor with stored data representing expected sensor outputs for the two positions of the end portion  58  (step  151 , FIG. 8) and selects the appropriate mode of operation according to the sensed position of inlet  59 —hose mode for inlet  59  in the upwardly pointing position (FIG. 4 a ) and auto mode for the inlet  59  in the downwardly pointing position (FIG. 4 b .) When the user presses the ‘GO’ switch  132  and hose mode has been selected, the control processor  140  issues control outputs to start the vacuum fan motor (output  136 , FIG. 7) but to inhibit the brush bar (outputs  137 ,  138 , FIG. 7.) The control processor  140  can also output a signal to user interface  135  to light an appropriate indicator lamp  133  indicating hose mode operation. During hose mode operation the control processor  140  does not need to operate its navigation system. 
     For autonomous mode operation, the control processor  140  issues control outputs to control use of the vacuum fan motor (output  136 , FIG.  7 ), the traction motors and the brush bar (outputs  137 ,  138 , FIG. 7.) The control processor  140  also outputs a signal to user interface  135  to light an appropriate indicator lamp  133  indicating autonomous operation. During autonomous mode, the control processor  140  receives inputs from the exterior sensors  19 ,  40  and uses this information to navigate around an arm 
     The invention is not intended to be limited to the precise details of the embodiment described above. Most importantly, the invention is not to be regarded as applicable only to vacuum cleaners with cyclonic separators or which are robotic in nature, although the specific example described above indicates that the invention has application in these areas. The cyclonic separator illustrated in the drawings could be replaced by a bag filter with a shell or part-shell surrounding it in order to give it some structure, or by a bag filter merely fitted with a rigid inlet which would then be attachable to the cleaner head in one configuration and to a clip or holder to allow a hose to be attached in another configuration. It is also envisaged that the whole of the cyclonic separator shown in the drawings (or an equivalent non-cyclonic separator) could be rotatable or otherwise movable as a whole, i.e. the end portion is always connected to the bin in the same configuration but the whole cyclonic separator is rolled though 180°, in order to move the tangential inlet from the first position into the second position. This arrangement is also intended to be included within the scope of the invention along with arrangements in which the cyclonic separator, or the part incorporating the inlet, is rolled through other angles, such as 90°, between the first and second positions. The invention is, of course, applicable to any type of vacuum cleaner which requires to be converted between a first mode in which the dirty air is drawn in though a cleaner head and a second mode in which the dirty air is drawn in rough a hose. It will be appreciated from the above description that the means by which the cleaner is propelled across the surface to be cleaned, the means by which the cleaner head is attached to the chassis, the means by which the cleaner (if it is robotic) senses and avoids obstacles and other nonessential features are all immaterial to the present invention. 
     An alternative aspect of the invention controls operation of the agitating device within the cleaner head according to whether the cleaner head or the alternative dirty air inlet is being used. For this aspect of the invention, the inlet of the dirt and dust separating apparatus, or the entire dirt and dust separating apparatus incorporating the inlet, may be movable between two positions. Alternatively, the dirt and dust separating apparatus can have two inlets: a first inlet from the cleaner head, and a second inlet from an alternative dirty air inlet. FIG. 9 shows this alternative form. Dirt and dust separating apparatus  52  has inlet ducting  220  which can receive dirty air from the cleaner head  22  or an alternative dirty air inlet. A sensor  202  at the alternative dirty air inlet senses the presence of a hose at the inlet and supplies a sensing signal  210  indicative of the presence of a hose at the inlet or of a cover to the alternative inlet being moved to insert a hose. In response to receiving inlet sensing signal  210 , the control processor  140  issues a cleaner head inlet control signal  212  to control inlet valve  204 , or an inlet changeover control signal  206  to operate changeover valve  206 , to close one of the inlet paths such that the dirt and dust separating apparatus receives a dirty airflow from only one of the inlet paths. The control processor  140  also issues a brush bar control signal  138  to inhibit operation of the brush bar whenever the alternative dirty air inlet is being used. The cleaner head may have a brush bar or some other device to agitate the floor surface beneath the cleaner head  22 .