Patent Publication Number: US-2007095028-A1

Title: Upright vacuum cleaner

Description:
BACKGROUND  
      This description relates to upright vacuum cleaners used for suctioning dirt and dust from carpets and floors.  
      Upright vacuum cleaners include a cleaner body having a handle, by which an operator of the vacuum cleaner may grasp and maneuver the cleaner, and a nozzle section which travels across a floor, carpet, or other surfaces being cleaned.  
      The cleaner body is often formed as a rigid plastic housing which encloses a dirt and dust collecting filter bag. The nozzle section is connected through a hinge to the cleaner body such that the cleaner body is pivotable between a generally vertical upright storage position and an inclined operative position. The underside of the nozzle section includes a suction opening formed therein which is in fluid communication with the filter bag.  
      A suction source, such as a motor and fan assembly, is enclosed either within the nozzle section or the cleaner body of the cleaner. The suction source generates the suction force required to pull dirt from the carpet or floor through the suction opening and into the filter bag.  
      Another type of upright vacuum cleaner utilizes cyclonic airflow to avoid the need for vacuum filter bags, and the associated expense and inconveniences of replacing filter bags. The cyclonic airflow is used instead of the filter bag to separate a majority of the dirt and other particulates from the suction airflow. The air is then filtered to remove residual particulates, returned to the motor, and exhausted.  
      However, conventional cyclonic airflow upright vacuum cleaners have not been found to be entirely effective and convenient to use. For example, with conventional cyclonic airflow vacuum cleaners, the process of emptying dust and dirt from dust collector may be inconvenient. Also, in a conventional vacuum cleaner having the above-mentioned configuration, the coupling structure of the dust collector may be complex and therefore difficult to use.  
      Also, in the conventional vacuum cleaner having the above-mentioned configuration, the suction source may become overheated when a clog occurs in the vacuum cleaner.  
     SUMMARY  
      In one general aspect, a vacuum cleaner includes a cleaner body, a dust collector coupled to the cleaner body, a suction source located in the cleaner body and having a suction source inlet in fluid communication with the dust collector and a suction source outlet, and a main filter assembly located on the dust collector for filtering contaminants from the airflow.  
      The dust collector includes a cyclonic chamber providing a cyclonic airflow for separating contaminants entrained in the airflow and a dust collecting container for storing the contaminants.  
      The cyclonic chamber includes a primary cyclone and at least one secondary cyclone. The primary cyclone may be provided in fluid communication with the cleaner body and/or may include a primary airflow inlet located on an upper portion of the primary cyclone at one side of the primary cyclone and a primary airflow outlet located on an upper portion of the primary cyclone at the center of the primary cyclone. The at least one secondary cyclone may be installed around the primary cyclone for separating contaminants entrained in the airflow discharged from the primary cyclone.  
      The dust collecting container may include a primary dust storing part for storing contaminants separated in the primary cyclone and secondary dust storing part for storing contaminants separated in the secondary cyclone.  
      The primary cyclone may have a cylindrical shape and the primary airflow inlet of the primary cyclone may be tangentially oriented in relation to an axial centerline of the primary cyclone. The secondary cyclones may have a partial conical shape and be partitioned with respect to each other by peripheral walls of the secondary cyclone.  
      The vacuum cleaner may include a coupling device for coupling the dust collector to the cleaner body.  
      The coupling device may have a coupling protrusion formed at the front of the cleaner body and/or a latch provided at the upper end of the dust collector.  
      The latch may have a fastening bar which moves upwardly for coupling the dust collector to the cleaner body and moves downward for detaching the dust collector from the cleaner body.  
      The fastening bar may include a hook corresponding to a mating groove formed in the coupling protrusion.  
      The main filter assembly may include a main filter element that includes an expanded polytetrafluoroethylene (PTFE) membrane.  
      The vacuum cleaner may also include a final filter assembly connected in fluid communication with the suction source outlet and adapted for filtering the airflow exhausted by the suction source prior to the airflow being dispersed into the atmosphere. The final filter assembly may include a high efficiency particulate arrest (HEPA) filter medium.  
      Upon activation of the suction source, contaminants from a surface being cleaned may be entrained in the airflow. The airflow travels (a) from the cleaner body into the primary cyclone through the primary airflow inlet, (b) downwardly from the primary airflow inlet and in a spiral within the primary cyclone so that the entrained contaminants are separated from the suction airflow, (c) upwardly from the primary cyclone into the secondary cyclone through a secondary airflow inlet of the secondary cyclone, (d) downwardly from the secondary airflow inlet and in a spiral within the secondary cyclone so that contaminants are separated from the airflow flowing into the secondary cyclone, and (e) upwardly from the secondary cyclone into the suction source passing through the main filter assembly and outwardly through an exhaust of the vacuum cleaner.  
      In accordance with another general aspect, a vacuum cleaner includes a nozzle section defining a suction opening, a cleaner body pivotally mounted to the nozzle section and in fluid communication with the nozzle section, a primary cyclone for separating contaminants from an airflow, the primary cyclone being in fluid communication with the suction opening, and at least one secondary cyclone for separating contaminants entrained in the airflow discharged from the primary cyclone.  
      A suction source may include a suction source inlet in fluid communication with the secondary cyclone and a suction source outlet in fluid communication with the atmosphere.  
      A thermal protection device may be provided for preventing a motor of the suction source from overheating.  
      A conduit may operatively connect the suction opening in fluid communication with a primary airflow inlet of the primary cyclone.  
      A fitting member may support and connect the conduit to a passage which is in fluid communication with the suction opening.  
      A main filter assembly may include a main filter element, wherein the main filter element is located on an upper portion of the secondary cyclone.  
      The main filter element may be supported by a filter support member. The primary airflow inlet may be tangentially oriented and arranged so that the airflow entering the primary cyclone through the primary airflow inlet moves spirally within the primary cyclone.  
      In another general aspect, an upright vacuum cleaner may include a nozzle section defining a suction opening; a cleaner body coupled with the nozzle section about a hinge; a primary cyclone for separating contaminants from an airflow, the primary cyclone being in fluid communication with the suction opening; and at least one secondary cyclone for separating contaminants entrained in the airflow discharged from the primary cyclone.  
      A suction source may include a suction source inlet in fluid communication with the secondary cyclone and a suction source outlet in fluid communication with the atmosphere.  
      A main filter assembly may include a main filter element, the main filter element being located on an upper portion of the at least one secondary cyclone.  
      The at least one secondary cyclone may be disposed in a position around a periphery of the primary cyclone.  
      The vacuum cleaner may include a plurality of secondary cyclones.  
      The secondary cyclones may be partitioned from an adjacent secondary cyclone, such as by the peripheral walls of the secondary cyclones.  
      A primary airflow inlet of the primary cyclone may be tangentially oriented and arranged so that the airflow entering the primary cyclone through the primary airflow inlet moves spirally within the primary cyclone.  
      A conduit may operatively connect the suction opening in fluid communication with a primary airflow inlet of the primary cyclone.  
      In another general aspect, a method provides a way of cleaning a surface with an upright vacuum cleaner having a suction source, a cleaner body, a dust collector coupled to the cleaner body, a dust collecting container and a filter assembly, the dust collector including a cyclonic chamber having a primary cyclone in fluid communication with the cleaner body and at least one secondary cyclone disposed around a periphery of the primary cyclone.  
      The method may include activating the suction source to produce an airflow pathway for entraining contaminants from the surface into the airflow pathway.  
      The method may include exhausting air from the upright vacuum cleaner.  
      The airflow pathway may extend from the cleaner body of the vacuum cleaner into the primary cyclone.  
      The airflow pathway may extend in a spiral within the primary cyclone so that the entrained contaminants are separated from the suction airflow.  
      The airflow pathway may extend upwardly from the primary cyclone into the at least one secondary cyclone.  
      The airflow pathway may extend in a spiral within the at least one secondary cyclone so that contaminants are separated from the airflow flowing into the secondary cyclone.  
      The airflow pathway may extend upwardly from the secondary cyclone and passing through the main filter assembly.  
      Such a vacuum cleaner may provide a simple coupling structure, is convenient to use, and may prevent a suction source from overheating during operation, such as when a clog occurs in the vacuum cleaner.  
      Other features and advantages will be apparent from the following description, including the drawings, and the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a perspective view of a cyclonic airflow upright vacuum cleaner.  
       FIG. 2  is a side view of the vacuum cleaner of  FIG. 1 .  
       FIG. 3  is a rear view of the vacuum cleaner of  FIG. 1 .  
       FIG. 4  is a bottom, plan view of the vacuum cleaner of  FIG. 1 .  
       FIG. 5  is a partial, side sectional view of the vacuum cleaner of  FIG. 1 .  
       FIG. 6  is an exploded, perspective view of the dust collector shown in  FIG. 1 .  
       FIG. 7  is a perspective view of an upper part of the dust collector of  FIG. 6 .  
       FIG. 8  is a partial, side sectional view of the dust collector of  FIG. 6 .  
    
    
     DETAILED DESCRIPTION  
      Referring to  FIGS. 1-5 , an upright vacuum cleaner includes a cleaner body  100 , a nozzle section  200  connected to the cleaner body  100 , and conduits for guiding the suction airflow from the nozzle section  200  to the atmosphere through the cleaner body  100 .  
      The cleaner body  100  and the nozzle section  200  are connected through a pivot or hinge, such as a suitable hinge assembly, so that the cleaner body  100  pivots between a generally vertical storage position (as shown) and an inclined, operative position.  
      The nozzle section  200  includes a nozzle case  210 , a suction opening  211  which is formed at the underside of the nozzle case  210 , and a rotating brush assembly which is provided in the nozzle case  210 . Front wheels  121  and rear wheels  120  are rotatably mounted to the underside of the nozzle case  210  to enable the nozzle section  200  to smoothly move on a floor.  
      The suction opening  211  extends substantially across the width of the nozzle case  210  at the front end thereof. The suction opening  211  is in fluid communication with the cleaner body  100  through a first conduit  410 .  
      The rotating brush assembly includes an agitator  220 , an agitator brush  230  which is provided at the outer circumference of the agitator  220 , and a belt  240  for transferring the rotational force of a suction source  180  to the agitator  220 .  
      The agitator  220  is positioned in the region of the suction opening  211  for contacting and scrubbing the surface being vacuumed to loosen embedded dirt and dust. When the rotational force of the suction source  180  is transferred to the agitator  220 , the agitator rotates and brushes up contaminants from the surface being cleaned. The rotating brush assembly may further include an agitator motor (not shown) for driving the agitator.  
      A height adjustment knob  110  is rotatably mounted in the nozzle section  200 . The user rotates the height adjustment knob  110  with his/her hand to raise or lower a shaft supporting front wheels (not shown) of the vacuum cleaner, and thus adjust the height of the nozzle section  200 . In one implementation, the height adjustment knob  110  is capable of adjusting the height of the nozzle section incrementally and in accordance with the state of the surface to be cleaned.  
      The cleaner body  100  includes a control part (not shown) for controlling the vacuum cleaner, the suction source  180  for generating the required suction airflow for cleaning operations, and a dust collector  300  for separating contaminants entrained in the suction airflow passed through the suction opening  211 . The cleaner body may also include a coupling device including a latch  327  and a coupling protrusion  190  for coupling the dust collector to the cleaner body.  
      The suction source  180  includes an electronic motor and a fan generating a suction force in a suction source inlet  181  and an exhaust force in a suction source outlet  183 . The suction source outlet  183  is in fluid communication with a final filter assembly  600  for filtering the exhaust airflow of any contaminants immediately prior to their discharge into the atmosphere. The suction source inlet  181  is in fluid communication with the dust collector  300  of the cleaner body  100 . Alternatively, the suction source may be disposed in the nozzle section  200 .  
      The cleaner body  100  further includes a motor protector  160  for preventing a motor of the suction source from overheating. The motor protector  160  includes a bypass valve (not shown) which automatically opens to provide cooling air to the motor when a clog prevents the normal flow of air to the motor. The cleaner body  100  may also include a thermal protector (not shown) for protecting the vacuum cleaner from overheating. If a clog prevents the normal flow of air to the motor of the suction source, the thermal protector automatically turns the motor off to allow the motor to cool in order to prevent possible damage to the vacuum cleaner.  
      The cleaner body  100  further includes a handle  700  extending upward therefrom by which a user of the vacuum cleaner is able to grasp and maneuver the vacuum cleaner. The handle  700  includes a telescopic release lever  710  for adjusting the height of the handle according to a height of the user.  
      When the user wants to raise the handle  700 , the user pulls the telescopic release lever  710  up with their fingers and to extend the handle  700 . The user pulls the telescopic release lever  710  up with their fingers and pulls down on the handle  700  to lower the handle  700 .  
      The cleaner body  100  further includes a cord hook provided at rear side of the cleaner body  100 . The cord hook includes an upper cord hook  141  and a lower cord hook  140  corresponding to the upper cord hook. The space between the upper cord hook  141  and the lower cord hook  140  is sufficient to accommodate the number of turns necessary to store the entire length of the cord. A cord holder (not shown) adjacent to the cord hook prevents the cord releasing from its stored position.  
      The conduits include a first conduit  410  connecting the suction opening  211  to dust collector  300 , a second conduit  420  connecting the dust collector  300  to the suction source inlet  181 , and a third conduit  430  connecting the suction source outlet  183  to the atmosphere.  
      The first conduit  410  includes hoses supported and connected by fitting members. One side of a first fitting member  171  is connected to a first hose  411  and the other side of the first fitting member  171  is connected to a passage  170  which is in fluid communication with the suction opening  211 .  
      A second fitting member  173  connects the first hose  411  to a second hose  412  and a third fitting member  175  connects the second hose  412  to the cleaner body. Each of the first and second hoses ( 411 ,  412 ) is connected detachably to the second fitting member  173 .  
      The vacuum cleaner further includes body release pedal  130  for an inclined operative position of the vacuum cleaner. The body release pedal  130  is pivotably mounted on a mounting portion  131  which is provided at the nozzle section. The body release pedal  130  has a locking protrusion (not shown) protruding from a side thereof. The locking protrusion is sequentially locked into one or more locking recess (not shown) provided at lower side of cleaner body.  
      When the vacuum cleaner is in use, with cleaner body  100  being rotated at a predetermined angle with respect to a surface to be cleaned, a locking protrusion is locked in one of the inclined position recesses.  
      Referring to  FIGS. 6-8 , the dust collector  300  includes a cyclonic chamber  320 , a dust collecting container  330 , a bottom panel  340  which is positioned at lower end of the dust collecting container  330  and a top cover  310  which is positioned at an upper end of the dust collecting container  330  and detachably connected to the dust collecting container  330 .  
      The dust collector  300  further includes a dust collector handle  350  which is provided on the exterior of the dust collecting container  330  for handling the container. The latch  327  is positioned at the upper end of the dust collector handle  350  and the coupling protrusion  190  is formed at the front portion of the cleaner body for coupling the dust collector  300  to the cleaner body  100 . The latch  327  includes a fastening bar  327   a  having a hook  327   b , and the coupling protrusion  190  includes a mating groove (not shown) corresponding to the hook.  
      When the user intends to couple the dust collector  300  to the cleaner body  100 , the user inserts the dust collector into a socket  195  formed in the cleaner body. Next, the user moves the fastening bar  327   a  upward. The hook  327   b  of the fastening bar is then inserted into the mating groove of the coupling protrusion  190 . The fastening bar  327   a  may also be biased through use of a spring or other resilient member, or via the natural resiliency of the plastic from which it is molded.  
      The cyclonic chamber  320  includes a primary cyclone  321  and at least one secondary cyclone  323 . The primary cyclone  321  separates dust and dirt from the suction airflow passed through the suction opening  211 . The secondary cyclone  323  separates dust and dirt entrained in the airflow discharged from the primary cyclone  321 .  
      The primary cyclone  321  has a downwardly-opened cylindrical container shape. A primary airflow inlet  321   a  is formed through an upper portion of the primary cyclone  321  at one side of the primary cyclone  321 . A primary airflow outlet  321   b  is formed through the top of the primary cyclone  321  such that the primary airflow outlet  321   b  extends vertically.  
      The primary airflow inlet  321   a  is tangentially oriented and arranged so that the airflow entering the primary cyclone  321  through the primary airflow inlet  321   a  moves cyclonically within the primary cyclone  321 . That is, the primary airflow inlet  321   a  guides dirt-laden air into the cyclonic chamber  320  in a tangential direction of the primary cyclone  321  so that the air flows spirally along an inner wall surface of the primary cyclone  321 .  
      The secondary cyclones  323  have peripheral walls formed integrally with a peripheral wall of the cyclonic chamber  320 , respectively. The secondary cyclones  323  are partitioned from each other by peripheral walls of the secondary cyclones  323 . The cyclonic chamber  320  may be constructed as a single piece with the dust collecting container  330  and at least partially defining the dust collecting container  330 .  
      In particular, the secondary cyclones  323  are circumferentially arranged around the primary cyclone  321 . Each secondary cyclone  323  has an upper end upwardly protruded to a level higher than that of the upper end of the primary cyclone  321 .  
      The peripheral wall of each secondary cyclone  323  is vertically cut out at a region where the peripheral wall is upwardly protruded above the upper end of the primary cyclone  321 , thereby forming a secondary airflow inlet  323   a  communicating with the primary airflow outlet  321   b.    
      Each secondary cyclone  323  also has a partial, conical shape. That is, the secondary cyclone  323  has a conical portion formed at a lower portion of the secondary cyclone  323  such that the conical portion has a diameter reduced gradually as the conical portion extends toward the bottom of the dust collecting container  330 .  
      A contaminants discharge port  323   c  is formed at a lower end of each secondary cyclone  323  to downwardly discharge contaminants such as dust.  
      The secondary cyclones  323  have an integrated structure such that adjacent cyclones  323  of the secondary cyclones  323  are in contact with each other to prevent air from leaking between adjacent secondary cyclones  323 .  
      The cyclonic chamber  320  may further include a chamber cover  325  mounted to the upper end of the cyclonic chamber  320  to open or close the upper ends of the secondary cyclones  323 .  
      A flow passage guide  326  is provided at the underside of the chamber cover  325 . The flow passage guide  326  more smoothly guides air emerging from the primary airflow outlet  321   b  to the secondary cyclones  323 .  
      The secondary airflow inlet  323   a  of each secondary cyclone  323  guides air discharged from the primary airflow outlet  321   b  to flow in a tangential direction of the secondary cyclone  323 , so that the air entering the secondary airflow inlet  323   a  flows spirally along an inner wall surface of the secondary cyclone  323 .  
      Secondary airflow outlets  323   b  are formed at the chamber cover  325  along the peripheral portion of the chamber cover  325  to discharge air from the secondary cyclones  323 , respectively.  
      Dust separated in the primary cyclone  321  and second cyclones  323  is stored in a dust storing part formed by the dust collecting container  330 . The stored dust is subsequently outwardly discharged by virtue of gravity when the bottom panel  340  is opened.  
      An opening/closing device  360  is mounted to the peripheral wall of the dust collecting container  330  to open or close the bottom panel  340 . The opening/closing device  360  includes a locking hook  361  for locking the bottom panel  340 . The bottom panel  340  may also include a mating hook  341  corresponding to the locking hook  361 .  
      The dust collecting container  330  may be at least partially transparent so that an operator of the vacuum cleaner is able to view the level of dirt and dust accumulated therein for purposes of determining when the dust collecting container should be emptied.  
      The dust storing part includes a primary dust storing part  331  for storing the dust separated by the primary cyclone  321 , and a secondary dust storing part  333  for storing dust separated by the secondary cyclones  323 .  
      The primary dust storing part  331  and secondary dust storing part  333  are partitioned by a substantially cylindrical boundary wall  335 , which is connected to the secondary cyclones  323 , and has a diameter smaller than that of the peripheral wall of the dust collecting container  330 .  
      The boundary wall  335  has a lower end extending downward to the bottom of the dust collecting container  330 , that is, the upper surface of the bottom panel  340 , beyond the lower end of the primary cyclone  321 .  
      The boundary wall  335  may have a circumferentially corrugated shape, in order to prevent the dust stored in the primary dust storing part  331  from floating due to a spiral air flow formed in the primary cyclone  321 .  
      A sealing member  342  is mounted between the boundary wall  335  and the bottom panel  340 . The sealing member  342  may be formed of an elastic material and/or be formed having a cylindrical shape. The sealing member  342  prevents the primary dust storing part  331  from communicating with the secondary dust storing parts  333 .  
      In addition to the above-described configuration, the dust collector  300  may include a discharge member  370  mounted on the upper end of the primary cyclone  321 . A plurality of holes  371  are formed at a peripheral wall of the discharge member  370 , in order to allow the discharge member  370  to communicate with the primary airflow outlet  321   b  of the primary cyclone  321 .  
      It is preferred that the discharge member  370  be centrally arranged in the primary cyclone  321 , extend axially through the primary cyclone  321 , and have a substantially conical structure having an opened upper end and a closed lower end while having a diameter gradually reduced as the discharge member  370  extends downward.  
      When the discharge member  370  has such a structure, the velocity of the spiral air flow in the primary cyclone  321  is gradually reduced toward the lower end of the primary cyclone  321 . Therefore, it is possible to prevent dust from being influenced by a suction force exerted in the discharge member  370 . Alternatively, the discharge member  370  may be formed having different shapes, such as a cylindrical shape.  
      The upper end of the discharge member  370  is operatively coupled with the peripheral edge of the primary airflow outlet  321   b . An annular sealing member (not shown), which provides a sealing effect, may be interposed between the upper end of the discharge member  370  and the primary airflow outlet  321   b.    
      A floatation prevention member  373  may also be mounted to the lower end of the discharge member  370 , in order to prevent the dust collected in the primary dust storing part  331  from rising due to the spiral air flow, and thus, from re-entering the flow of air to the primary cyclone  321 .  
      For such a function, it is preferred that the floatation prevention member  373  have a radially-extending structure formed integrally with the lower end of the discharge member  370 . It is also preferred that the floatation prevention member  373  has a downwardly-inclined upper surface. Specifically, the floatation prevention member  373  has a conical structure having a diameter gradually increased as the floatation prevention member  373  extends downward.  
      A cross blade  375  may also be attached under the floatation prevention member  373  for preventing swirling airflow in the primary dust storing part  331 . The cross blade  375  may help to reduce air turbulence in the primary dust storing part  331  that may cause dust to rise up.  
      The dust collector  300  also includes a guide rib  380  provided at the primary cyclone  321 . The guide rib  380  guides air entering the primary airflow inlet  321   a  to flow in a direction tangential to the inner peripheral wall surface of the primary cyclone  321 . That is, the guide rib  380  prevents the air entering the primary airflow inlet  321   a  from being directly introduced into the discharge member  370 .  
      A main filter assembly  500  is located on the dust collector  300  for filtering contaminants from the airflow discharged from the secondary cyclone  323 . Referring to FIGS.  1 - 5 , the main filter assembly  500  includes a filter housing  510  and a main filter element  520  mounted in the filter housing  510  and a filter housing knob  530  for handling the filter housing.  
      The filter housing  510  coupled detachably to the cleaner body receives and retains the main filter element  520 . The filter housing  510  includes a plurality of apertures, slots, or other passages formed therethrough, preferably in the lower half thereof, so that the suction airflow flows freely from the cover discharge port  313  into the filter housing  510  and to the main filter element  520 .  
      It is preferable that the main filter element  520  is made of permeable material. For cleaning the main filter element  520 , the user is able to detach the filter housing  510  from the cleaner body by rotating and drawing out the filter housing knob  530 .  
      The main filter element  520  may include Porex. RTM brand high density polyethylene-based open-celled porous media available commercially from Porex Technologies Corp., Fairburn, Ga. 30213, or an equivalent foraminous filter member. The main filter element  520  may be a rigid open-celled foam that is moldable, machinable, and otherwise workable into any shape as deemed advantageous for a particular application.  
      The main filter assembly  500  may further include a filter support member (not shown) for supporting and securing the main filter element  520 . The filter support member is formed at the inner frame of the filter housing.  
      The cleaner body  100  also may include a final filter assembly  600  for filtering the suction airflow immediately prior to its exhaustion into the atmosphere. The preferred final filter assembly  600  includes a final filter element  610  and a final filter housing  620  for retaining the final filter element.  
      The final filter element  610  is preferably a high efficiency particulate arrest (HEPA) filter element in a sheet or block form. The final filter housing  620  has protective grid or grate structure for securing the final filter element  610  in place.  
      The final filter assembly  600  will remove the contaminants, such that only contaminant-free air is discharged into the atmosphere.  
      An exemplary operation of the vacuum cleaner having the dust collector  300  of  FIGS. 1-8 , will be described in greater detail hereinafter.  
      The suction source  180  establishes a suction force at its suction source inlet  181 , in the elongated first conduit  410 , and thus in the primary cyclone  321 .  
      This suction force or negative pressure in primary cyclone  321  is communicated to the suction opening  211  formed in the nozzle underside through the hoses and associated fitting members. In combination with the scrubbing action of the rotating brush assembly, the suction force causes dust and dirt from the surface being cleaned to be entrained in the suction airflow and pulled into the primary cyclone  321  through the primary airflow inlet  321   a.    
      The air introduced into the primary cyclone  321  is guided by the guide rib  380  to flow in a direction tangential to the inner peripheral surface of the primary cyclone  321  without being directly introduced into the discharge member  370 , thereby imparting a spiral flow to the airflow entering the primary cyclone  321 .  
      The air acquires a certain swirling force, and the swirling force separates heavy and large dust particles. As a result, relatively heavy and large dust is separated from the air in accordance with the cyclone principle, and is then stored in the primary dust storing part  331  after falling downward.  
      The dust stored in the primary dust storing part  331  is prevented from floating in accordance with the functions of the floatation prevention member  373  and corrugated boundary wall  335 .  
      The air, from which relatively heavy and large dust has been separated, is discharged from the primary cyclone  321  through the primary airflow outlet  321   b  communicating with the holes  371  formed at the peripheral wall of the discharge member  370 .  
      The finer dust is then filtered through the discharge member  370  placed between the primary cyclone  321  and the secondary cyclones  323 . Also, the air is then introduced into the secondary cyclones  323  so that the air is again subjected to a dust separation process, in order to separate relatively light and fine dust from the air.  
      The air, from which relatively light and fine dust has been separated in the secondary cyclones  323 , is introduced into the interior of the top cover  310  through the secondary airflow outlets  323   b . The air introduced into the interior of the top cover  310  is discharged through a cover discharge port  313  formed at the center of the top cover  310 . The air emerging from the cover discharge port  313  is introduced into the main filter assembly  500 .  
      The air passes through the apertures formed in the filter housing  510 , passes through the main filter element  520  so that residual contaminants are removed, and exits the main filter assembly  500 . The air discharging from the main filter assembly  500  is introduced into the suction source  180  through the second conduit  420 . The air emerging from the suction source outlet  183  is then introduced into the final filter assembly  600  through the third conduit  430 .  
      In the final filter assembly  600 , the air is filtered again by the HEPA filter to remove any contaminants that passed through the dust collector  300  and the main filter assembly  500 . The air passed through the final filter assembly  600  is outwardly discharged from the vacuum cleaner to atmosphere.  
      Implementations of the above-described vacuum cleaner may provide one or more of the following advantages. For example, the simple coupling structure may be relatively convenient to use since the dust collector can be coupled to the cleaner body by virtue of operation of the latch corresponding to the coupling protrusion. The motor of the suction source may be prevented from overheating due to clogging by automatically controlling a bypass valve for providing cooling air to the motor. The vacuum cleaner may also separate dust and dirt from the airflow and deposit the dust and dirt into the dust collecting container easily and conveniently.  
      Other implementations are within the scope of the following claims.