Abstract:
A bagless vacuum cleaner includes a separating unit for separating dirt and dust from a dirt-laden airflow which is drawn in by the cleaner. The separating unit has a chamber with a collection area for collecting dirt and dust which is separated from the airflow. A base of the separating unit is movable between a closed position and an open position. The base may be released by a trigger and a linking mechanism. The releasing mechanism is operable to apply an opening force to the base to push the base open, thereby allowing a tightly fining seal to be fitted to the base.

Description:
FIELD OF THE INVENTION 
   This invention relates to a collecting chamber for a bagless vacuum cleaner and to a vacuum cleaner which incorporates the collecting chamber. 
   BACKGROUND OF THE INVENTION 
   Vacuum cleaners which separate dirt and dust from an airflow without the use of a filter bag, so-called bagless vacuum cleaners, are becoming increasingly popular. Most bagless cleaners use cyclonic or centrifugal separation to spin dirt and dust from the airflow. By avoiding the use of a filter bag as the primary form of separation, it has been found possible to maintain a consistently high level of suction, even as the collecting chamber fills with dirt. 
   The principle of cyclonic separation in domestic vacuum cleaners is described in a number of publications including EP 0 042 723. In general, an airflow in which dirt and dust is entrained enters a first cyclonic separator via a tangential inlet which causes the airflow to follow a spiral or helical path within a collection chamber so that the dirt and dust is separated from the airflow. Relatively clean air passes out of the chamber whilst the separated dirt and dust is collected therein. In some applications, and as described in EP 0 042 723, the airflow is then passed to a second cyclone separator which is capable of separating finer dirt and dust than the upstream cyclone. The airflow is thereby cleaned to a greater degree so that, by the time the airflow exits the cyclonic separating apparatus, the airflow is almost completely free of dirt and dust particles. 
   While bagless vacuum cleaners are successful in maintaining a consistently high level of suction, the absence of a bag can make it difficult to dispose of the dirt and dust which is collected by the cleaner. When the separating chamber of a bagless cleaner becomes full, a user typically removes the collecting chamber from the chassis of the machine, carries the chamber to a dust bin or refuse sack and tips the chamber upside down. Often dirt and dust is densely packed inside the collecting chamber and it may be necessary for a user to manually dislodge the dirt by reaching into the chamber and pulling at the collected mass of dust and fibres, or to shake or bang the collecting chamber against the side of a dustbin. In some cases, this can cause a fair amount of mess. 
   Some solutions to this problem have been proposed. U.S. Pat. No. 5,090,976 describes the use of a disposable liner which can be fitted inside the cyclonic separating chamber. When the liner is full, the liner is lifted out of the chamber and disposed of. WO 98/10691 describes a cyclonic collection chamber where a bag is retained, in a collapsed state, in the base of the collection chamber. When the collection chamber is full, the base is unscrewed from the chamber so that the bag can extend downwardly from the base. Dirt and dust slides out of the collecting chamber into the bag and the bag can then be sealed and separated from the collecting chamber for disposal. Both of these solutions have a disadvantage in that they require a user to keep a supply of spare bases or liners, which adds to the cost of maintaining the machine. 
   EP 1 023 864 describes a dust-collecting device for a cyclonic vacuum cleaner. The dust-collecting chamber can be removed from the chassis of the cleaner for emptying. A bottom lid of the dust-collecting chamber is attached by way of a hinge to the remainder of the chamber and the lid can be released by pressing a release button. A ribbed cylindrical filter is fitted inside the dust-collecting chamber and is rotatable within the chamber to encourage the release of dirt which is stored in the chamber. 
   SUMMARY OF THE INVENTION 
   The present invention seeks to provide a bagless vacuum cleaner in which collected dirt and dust can be conveniently disposed of. 
   Accordingly, a first aspect of the present invention provides a collecting chamber for a bagless vacuum cleaner comprising an inlet for receiving a dirt-laden airflow, an air outlet, a collection area for collecting, in use, dirt and dust which has been separated from the airflow and wherein part of the chamber wall in the region of the collection area is a closure member which is movable between a closed position in which the closure member seals the chamber and an open position in which dirt and dust can escape from the collection area, the chamber further comprising releasing means for releasing the closure member from the closed position, the releasing means comprising a manually operable actuating member which is located remotely from the closure member and wherein the releasing means is operable to apply an opening force to the closure member. 
   The positioning of the manually operable actuating member remote from the closure member has the advantage that the user is spaced from the dust as the dust empties from the separator. The feature of the releasing means applying an opening force to the closure member has the advantage that the closure member reliably opens without a user needing to touch the closure member. This allows an effective, tightly-fitting seal to be fitted to the closure member which, without the assistance of the opening force, would cause the closure member to ‘stick’ in the closed position. 
   The term ‘bagless’ is intended to cover a broad range of vacuum cleaners which have a reusable collecting chamber, and includes, inter alia, cleaners which separate dirt and dust by way of cyclonic, centrifugal or inertial separation. 
   Preferably the closure member is pivotably attached to the chamber and the releasing means is operable to apply an opening force to the closure member at a position which is spaced from the pivot, thereby providing a strong opening force. 
   The seal between the closure member and the wall of the chamber can be a tightly-fitting seal which exerts a radially-directed force against the wall of the chamber. An advantage of a radial seal is that the part of the chamber where the seal acts does not need to be widened to form a seat for the seal, which would be the case with an axially-directed seal. Any widening of the base may also cause dirt to settle in this region rather when the collecting chamber is emptied. 
   It is convenient for the actuating member to be located adjacent a handle for carrying the collecting chamber. This allows a user to carry and empty the collecting chamber with one hand. 
   Preferably the collecting chamber is removable from a stowed position on a chassis of a vacuum cleaner and the actuating member is inhibited from opening the closure member when the collecting chamber is in the stowed position. This prevents accidental release of the closure member, which may cause dust to escape from the collecting chamber. 
   Preferably agitating means are provided for agitating dirt held within the collection area, the agitating means being operable by the actuating member. This helps to dislodge any dirt that may have become ‘stuck’ in the collection area. Also, a user does not need to separately operate the release and the agitating means. 
   Preferably the closure member is pivotably fixed to the chamber. Also, it is preferable for the pivot to be located on the side of the chamber nearest the user such that the user is shielded from any dust which is released from the chamber. 
   The collecting chamber preferably comprises a cyclonic separator where dirt-laden air is spun at high speed to centrifugally separate dirt from the airflow but it can be any form of bagless separator where the collecting chamber is reused after it has been emptied. 
   The collecting chamber can have more than one separation stage. Preferably the collection areas of the first, second (and further) stage separators each lie adjacent the closure member such that all of the collected dirt and dust can be readily emptied from the collecting chamber. 
   A further aspect of the invention provides a vacuum cleaner incorporating a collecting chamber of the kind described above. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: 
       FIG. 1  shows a bagless vacuum cleaner; 
       FIG. 2  shows just the dirt and dust separation unit of the vacuum cleaner of  FIG. 1 ; 
       FIG. 3  is a cross-section along line A—A of the dirt and dust separation unit of  FIG. 2 , with the base of the unit in a closed position; 
       FIG. 4  shows the same cross-section as  FIG. 3  but with the base in a partially open position; 
       FIG. 5  shows the same cross-section as  FIG. 3  but with the base in a fully open position; 
       FIG. 6  is a cross-section through the dirt and dust separation unit mounted on the chassis of the vacuum cleaner; 
       FIG. 6A  is a more detailed view of the same cross-section as  FIG. 6 , showing the feature on the chassis which inhibits movement of the trigger release mechanism; 
       FIG. 7  is a more detailed view of the lower part of the cross-section of  FIG. 3 ; 
       FIG. 8  shows how dirt and dust accumulates in the dirt and dust separation unit, and, 
       FIGS. 9A–9C  show the seal of the vacuum cleaner in use. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIGS. 1 to 3 , a vacuum cleaner  10  has a main chassis  50  which supports dirt and dust separation apparatus  20 . The lower part of the cleaner  10  comprises a cleaner head  22  for engaging with the floor surface. The cleaner head has a downwardly facing suction inlet and a brush bar is mounted in the mouth of the inlet for agitating the floor surface. The cleaner head is pivotably mounted to a motor housing  24  which houses the motor and fan of the cleaner. Support wheels  26  are mounted to the motor housing for supporting the cleaner and allowing movement across a floor surface. A spine of the chassis  50  extends upwardly from the motor housing  24  to provide support for the components of the cleaner. A cleaning wand  42  having a second dirty air inlet  43  is connected by way of a hose (not shown) to the chassis at the base of the spine  50 . The wand  42  is releasable from the spine  50  so as to allow a user to carry out above-the-floor cleaning and cleaning in places which are inaccessible by the main cleaning head  22 . When the wand is fixed to the spine  50 , the wand  42  forms the handle of the cleaner and a handgrip  40  at the remote end of the wand  42  allows a user to manoeuvre the cleaner. These features of the cleaner are well known and have been well documented elsewhere and can be seen, for example, in cleaners which are manufactured by DYSON™, and thus will not be described in any further detail. 
   Dirty air from the cleaner head  22  or wand inlet  43  is carried to the separator unit  20  by inlet conduit  28  and inlet  30 . Separator  20  is a cyclonic separator which spins dirt, dust and other debris out of the airflow by centrifugal separation. One particular form of separator unit  20  is shown in detail in the figures as a preferred embodiment but it should be understood that there are many other ways in which the separator could be constructed. In the illustrated separator unit  20 , airflow passes through a first separation stage and then a second separation stage. The first separation stage is a substantially cylindrically-walled cyclonic chamber  205  whose purpose is to separate large debris and dirt from the airflow. Inlet  30  is arranged to direct dirty air into the chamber  205  in a tangential direction to the wall of the chamber. Fins or baffles  207  extend radially outwardly from a central core of the chamber and serve to discourage separated dirt or dust from becoming re-entrained in the airflow when the vacuum cleaner is first started. The outlet of the first separation stage is a shroud  235 , i.e. an apertured annular wall mounted coaxially inside the chamber  205 . The area on the inner side of the shroud leads to the second separation stage. The second separation stage is a set of tapered cyclonic chambers  240  which are arranged in parallel with one another. Each cyclonic chamber  240  has a tangential inlet  242 , an outlet  243  for separated dirt and dust and a cleaned air outlet  244 . Each of the cleaned air outlets  244  of the cyclonic chambers  240  communicate with an outlet conduit such that air from the individual outlets of the parallel cyclonic chambers is recombined into a single flow. The outlet conduit mates with a port on the chassis spine  50  when the separator unit  20  is fitted to the chassis. 
   In use dirty air which is laden with dirt, dust and other debris enters the first separation stage via inlet  30  and follows a spiral path around the chamber  205 . The centrifugal force acting on the material in the airflow causes the larger debris and dirt to be separated from the airflow. This separated material collects at the base of the chamber  205 , against base  210 , due to a combination of gravity and the pressure gradient which exists in chamber  205  while the cleaner is in operation. The airflow passes through the shroud  235 . The shroud  235  causes air to perform a sharp change of direction and causes fibrous material to collect on the outer wall of the shroud  235 . The airflow passes to the second separation stage where it is divided between the cyclonic chambers. Air enters a respective one of the chambers via a tangential inlet and is then constrained to follow a spiral path of decreasing radius which greatly increases the speed of the airflow. The speed is sufficient to separate dirt and extremely fine dust from the airflow. The separated dirt and dust exits the cyclonic chambers  240  via outlets  243  which communicate with a central conduit  245 . Dirt and dust falls, under gravity, towards the base of conduit  245  and collects at the lower end of the conduit  245  adjacent the base  210  in region  270  ( FIG. 8 ). Cleaned air from the parallel chambers  245  is recombined into a single flow and is channelled out of the separator unit  20 , down the spine  50  of the chassis and through a pre-motor filter, fan and post-motor filter before finally being exhausted from the cleaner. 
   It should be understood that the second separation stage need not be a set of parallel cyclonic chambers  240 . The second separation stage could be a single tapered cyclonic chamber which can fit inside the cylindrical chamber of the first separation stage, as shown in EP 0 042 723. Alternatively, the second separation stage could be a further cylindrical cyclone or it could be omitted altogether. The first separation stage may be a tapered chamber rather than the cylindrical one described. However, in each of these alternatives, dirt and dust will be separated from an airflow without the use of a filter bag and will collect in a collection area. 
   The separator unit  20  is supported by the chassis  50  and is releasably held upon the chassis by a catch  280 , shown more clearly in  FIG. 6A . The separator unit  20  is shown by itself in  FIGS. 2–5 . The separator unit  20  is releasable from the chassis to allow the separator to be emptied. A handle  202  is provided at the top of the separator unit  20  for allowing a user to carry the unit  20 . The base  210  of the separator unit is movable between a closed position (shown in  FIGS. 2 ,  3 ) and an open position (shown partially open in  FIG. 4  and fully open in  FIG. 5 ) to permit emptying of the unit  20 . The base  210  is hinged at  214  to the cyclone chamber  205  to allow pivotal movement between the base  210  and chamber  205 . Two separate collection areas lie adjacent to the base  210 . The first collection area is the annular region between the cylindrical chamber wall  205  and the inner wall  206  at the lower end of the separator. The second collection area  270  is the area within the tube-like part  206 . Thus, when base  210  opens, material empties from both of the collection areas. The outer annular edge of the base  210  has a radially inwardly extending slot to hold a seal  212 . In use, with the base closed, the seal  212  fits tightly against the inner wall of the chamber  205  to maintain an air and dust-tight seal. A second seal  213  extends axially outwardly from the lower annular edge of part  206  such that it fits tightly against the axially extending wall of the raised central cap of the base  210 . Seals could be located in other positions to achieve the same sealing effect of the base. The base  210  is held in the closed position by a lock mechanism  260 ,  262 . The locking mechanism is controlled by a manually operable trigger  220 . A linking mechanism  222 ,  223 ,  224 ,  230  joins the trigger  220  to the lock mechanism. Trigger  220  is received in a vertically extending channel on the spine-facing side of the separator which confines the trigger to follow a vertical movement. A lug on the trigger cooperates with a lever arm  222 . The lever is pivotably fixed to the housing such that the remote end of the lever arm pushes downwardly against the upper end  231  of push rod  230 . The push rod  230  is resiliently biased by spring  223  in the position shown in  FIG. 3  and can be displaced downwardly (to the position shown in  FIG. 4 ) against the action of the spring  223  when the trigger is pulled. Spring  223  is held in a cavity of the housing and respective ends of the spring  223  act against the end wall of the cavity and the flange which is carried by the push rod  230  near end  231 . The linking mechanism is shielded from dust by a gaiter  224 , which is attached to the push rod  230  and the housing of the separator unit. The gaiter  224  stretches as the push rod moves downwardly, maintaining a dust-tight shield for the mechanism behind the gaiter  224 . 
   The lowermost end of the push rod has an inclined face which cooperates with a similarly inclined face on the catch  260  at the base. Catch  260  is pivotably mounted to the base and can be displaced, against the bias of spring  262 , to the position shown in  FIG. 4 . The catch has a hook  263  which engages with a corresponding hooked feature  264  on the central part of the base  210  so as to hold the base  210  in the closed position. The lowermost surface of the catch  260  is curved such that when the base  210  is pushed towards the closed position the catch  260  is displaced, allowing the hook  264  on the base  210  to engage with the hook  263  on the catch  260 . 
   It will be appreciated that the trigger, linking mechanism and lock can be realised in many alternative ways. For example, the trigger  220  could be linked directly to the push rod  230 , rather than being indirectly linked by the lever  222 . 
   The lower end of the push rod  230  also carries an agitator  250 . The agitator  250  is fixed to the push rod and thus moves upwardly and downwardly with the push rod as the trigger  220  is operated. In use, a plug of dirt and dust may form at the lower end of the second collection area, next to base  210 . The agitator  250  has radially outwardly extending fins. In use, movement of the agitator will either push the plug or break the plug into smaller parts which can then fall out of the collection area. The inner surfaces of the collection tube are smooth and tapered to discourage dirt from settling. The agitator could be more elaborate than the one shown here. For example, the agitator could be arranged to rotate about the longitudinal axis of the push rod  230  as the push rod moves upwards or downwards. A second agitator could be provided in the first collection area, the second agitator also being linked to the push rod or release mechanism. The cutting effect of the agitator on a plug of material can be improved by forming sharp or pointed edges on the agitator. 
   To ensure an air and dust-tight seal around the base, the seal  212  fits tightly against the chamber. This may cause the base to ‘stick’ in the closed position when the catch  260  is released. The push rod  230  has a sufficient length such that, when it is operated, it moves downwardly towards the catch  260 , operates catch  260  and then continues to move towards the base  210 , pushing against the base, overcoming the resistance of the seal  212  against the chamber wall  205  and thus pushing the base  210  open. 
   In use, a user removes the separator unit  20  from the chassis by operating release member  280  and carries the separator unit  20 , by way of handle  202 , to a dust bin or refuse sack. The lower end of the separator unit is held over or within the dust bin or sack and the trigger  220  is pulled. This causes the base  210  to swing open and dirt, dust and debris which has been collected in the chamber  205  falls out of the unit  20  into the bin. Due to the distance between the handle and base, and the direction in which the dirt falls from the unit  20 , a user is not brought into contact with the dirt. As the dirt collects against the part of the chamber which opens, i.e. base  210 , the dirt falls out of the chamber  205  with little or no additional effort by a user. Fine dust collected within the second stage collector  270  can be fully cleared by the user operating trigger  220  several times. This will operate agitator  250 . 
   Referring again to  FIG. 8 , the region within tube-like part  206  forms a second stage collection area. For good cyclonic separation, it is important that the second stage collection area is sealed with respect to the first stage collection area which surrounds it. Collar-shaped seal  213  seals against the base  210  to achieve the seal between the first and second stage collection areas. A particular problem with sealing against the base  210  is that the base is exposed to dirt and dust which can prevent a reliable seal from being achieved.  FIGS. 9A–9C  show, in more detail, how the seal  213  fits against the base  210  during use. 
   Base  210  of the separator unit  20  has an inwardly tapering wall  201   a  and an upper wall  210   b . The collar shaped seal  213  has a diameter D S  which is narrower than the diameter D B  of the base  210  at the position at which the seal lies when the base  210  is fully closed. Seal  213  is formed from a resilient material such as a thermoplastic elastomer (TPE). By arranging for the seal  213  to project outwardly from the end of the tube  206 , the seal  213  provides no ledges on which fine dust can accumulate. The annular shape of the seal  213  helps to maintain the shape of the seal, even though it is only supported from the uppermost edge. 
     FIG. 9A–9C  show the base  210  being returned to a closed position against the chamber  205  after a user has emptied the chamber  205 . In  FIG. 9A  it can be seen that a layer of fine dust  300  covers the base  210 . In  FIG. 9B  the base  210  has been moved nearer to its final, closed, position. The lower end of seal  213  has stretched to accommodate wall  210   a  of the base  210 . Due to the tight fit between the leading edge  213   a  of the seal  213  and the wall  210   a , the layer of dust on the outermost surface of the wall  210   a  is pushed downwardly by the leading edge  213   a  of the seal  213 . Finally,  FIG. 9C  shows the base  210  in a closed position. The seal  213  has moved further down the wall  210   a  of the base. A significant portion of the seal  213  now lies firmly against a portion of the wall  210   a  which has previously been cleaned by the leading edge of the seal  213   a . Dust which has been displaced from the surface of the wall  210   a  accumulates  310  beneath the leading edge  213   a  of seal  213 . Thus, a reliable seal is achieved between seal  213  and base  210  even in the presence of dirt and dust. 
     FIG. 6  shows the separator unit  20  in position on the chassis  50  of the cleaner  10 . To ensure that the base  210  is not accidentally opened when the cleaner is in use, the chassis  50  has a projection  218  which fits inside a notch  217  on the trigger  220  when the separator unit  20  is fitted to the chassis  50 . Thus, the trigger  220  is inhibited from operating.