Patent Publication Number: US-9427126-B2

Title: Surface cleaning apparatus

Description:
FIELD 
     This specification relates to a surface cleaning apparatus. In a preferred embodiment, the surface cleaning apparatus has pre-motor filter dirt cup. In a particularly preferred embodiment, the surface cleaning apparatus is a portable hand carriable surface cleaning apparatus. 
     INTRODUCTION 
     The following is not an admission that anything discussed below is part of the prior art or part of the common general knowledge of a person skilled in the art. 
     Surface cleaning apparatus which utilize one or more cyclonic cleaning stages are known. Typically, a cyclone has an air inlet and an air outlet at the same end (e.g., the upper end). Dirt may accumulate in the other end (e.g., the bottom) of the cyclone chamber. Alternately, a dirt outlet may be provided in the bottom of the cyclone chamber so as to allow separated particulate matter to travel to a dirt collection chamber that is exterior to the cyclone chamber (see for example, US 2009/0205160). See also, US 2011/0314631, which discloses a cyclone chamber having an air inlet and an air outlet at one end and the end wall opposed to the end with the air inlet and the air outlet is spaced from the sidewall of the cyclone chamber by a variable amount so as to provide an outlet through which dirt may exit the cyclone chamber to an exterior dirt collection chamber. 
     SUMMARY 
     This summary is intended to introduce the reader to the more detailed description that follows and not to limit or define any claimed or as yet unclaimed invention. One or more inventions may reside in any combination or sub-combination of the elements or process steps disclosed in any part of this document including its claims and figures. 
     According to one broad aspect, a surface cleaning apparatus is provided with a uniflow cyclone chamber having a sidewall outlet. For example, the cyclone air inlet may be provided at a first end, the air outlet (e.g. vortex finder) may be provided at the second opposed end wall and a dirt outlet may be provided through a sidewall of the cyclone chamber at the second opposed end. For example, the dirt outlet may comprise an opening in the sidewall that extends radially around part of the sidewall of the cyclone chamber. The opening may be provided at the end wall of the cyclone chamber or it may be spaced therefrom (e.g., the sidewall may extend to the second opposed wall except at one location which defines a cut out or slot in the sidewall through which dirt may exit the cyclone chamber). Alternately, the sidewall may be spaced from the second opposed end wall so as to provide a gap (which may have a constant height or may have a variable height) through which dirt may exit the cyclone chamber. An advantage of this design is that a cyclone chamber having improved dirt separation efficiency is obtained. By enhancing the separation efficiency of the cyclone, a second stage cyclone may not be needed. In addition, removing an increased amount of particulate matter from the airstream passing through the cyclone chamber reduces the amount of entrained particulate matter which will be conveyed to an optional pre-motor filter, thereby extending the lifetime of the pre-motor filter before washing or replacement is required. 
     Optionally, the end wall of the cyclone chamber at the air inlet end may be rounded. For example, the air inlet end of the cyclone chamber may be shaped similar to a horizontal section through a toroid. Accordingly, the rounded portion may extend towards the opposed second end so as to define part of the sidewall of the cyclone chamber. 
     Optionally, in such an embodiment, the air inlet end of the cyclone chamber is openable so as to allow access to the interior of the cyclone chamber. The inner end of the rounded portion may be part of the openable end wall of the cyclone chamber. For example, the rounded portion may abut a facing edge of the sidewall or it may seat against an inner surface of the sidewall. Such a construction is advantageous as it allows the rounded end wall to be emptied while providing an appropriate seal at the opening end of the cyclone chamber. It will be appreciated that, optionally, an exterior dirt collection chamber may be openable at the same end as a cyclone chamber and, in such a case, it is preferably openable concurrently with the cyclone chamber. For example, a common floor or end wall may be utilized to close both the cyclone chamber and the dirt collection chamber. In such a case, the end wall of the dirt collection chamber and the half toroidal shape of the lower end of the cyclone chamber may be molded as a single piece. 
     It will be appreciated by a person skilled in the art that any of the features relating to the openable end wall of the cyclone chamber discussed herein may not be utilized with the uniflow cyclone construction disclosed herein but may be used by itself or with any other feature disclosed herein. 
     In accordance with another embodiment, a pre-motor filter is provided. Preferably, the pre-motor filter is provided with a transparent housing on the upstream (dirty) side of the pre-motor filter. The transparent housing permits a user to see the upstream side of the pre-motor filter and determine when the pre-motor filter may require cleaning. 
     In another embodiment, the pre-motor filter may be provided in a filter holder and the filter holder may be removable from the surface cleaning apparatus for cleaning or replacement of the pre-motor filter. The filter holder may define a chamber in which particulate matter conveyed from the cyclone chamber to the pre-motor filter may be stored. This may include particulate matter that is dis-entrained as the air changes direction to travel through the pre-motor filter and/or particulate matter that is separated from the airflow as the airflow enters the pre-motor filter. For example, the filter holder may comprise a cup having a sidewall and an end wall. The pre-motor filter may be placed in the cup spaced from the end wall with the pre-motor filter abutting the sidewall so as to define a dirt cup chamber between the end wall of the cup and the side of the pre-motor filter facing the end wall. An air conduit (e.g. an extension of the vortex finder) may extend through the foam into the dirt cup chamber. Accordingly, air exiting the cyclone chamber may travel through the conduit into the dirt cup chamber to reach the upstream side of the pre-motor filter and then travel through the pre-motor filter. Dirt may accordingly accumulate on the upstream side of the premotor filter. Optionally, the conduit may extend into the dirt cup chamber to a height above that of the pre-motor filter such that particulate matter may not fall downwardly through the conduit into the cyclone chamber. In accordance with such an embodiment, the filter holder may be removed from the surface cleaning apparatus and conveyed to a location (e.g. a sink or a garbage can) where the pre-motor filter may be removed so as to allow access to the dirt cup chamber so it may be emptied. Alternately, a portion of the dirt cup chamber may be openable. It will be appreciated that, in such an embodiment, the cup or at least the portion of a cup defining the dirt cup chamber may be transparent so as to allow a user to determine when the filter is dirty and/or the dirt cup chamber should be emptied. 
     Alternately, in some embodiments, the pre-motor filter may be positioned with the upstream side facing upwardly. Air may accordingly exit the cyclone chamber and travel, e.g., laterally through a duct to a position above the pre-motor filter. The air may then travel downwardly through the pre-motor filter. A sidewall may extend above the top of the pre-motor filter to define a dirt collection area. The portion of the duct or housing containing the pre-motor filter may be openable so as to allow access to the dirt collection area. When it is desired to remove dirt which has accumulated on top of the pre-motor filter, the duct or housing may be opened and the portion of the surface cleaning apparatus containing the pre-motor filter may be inverted to allow the dirt to be removed. 
     It will be appreciated by a person skilled in the art that any of the features of the pre-motor filter and pre-motor filter holder discussed herein need not be utilized with the uniflow cyclone design disclosed herein but may be used by themselves or in combination with any other feature disclosed herein. 
     In accordance with another embodiment, a pre-motor filter is provided with a pre-motor filter cleaner. For example, an agitation member may be provided to impact the pre-motor filter, preferably the upstream side thereof, so as to loosen dirt of the upstream side. The upstream side may then be emptied, e.g., by inverting the pre-motor filter (e.g. a pre-motor filter holder containing the premotor filter may be inverted thereby removing particular matter that has been loosened from the upstream side of the premotor filter). It will be appreciated that this feature is preferably used with the pre-motor filter dirt cup or dirt collection area discussed herein. 
     An advantage of this design is that the required amount of time between washing or replacing the pre-motor filter may be increased since the increase in back pressure caused by a dirty pre-motor filter may be reduced, particularly if the upstream side of the pre-motor filter faces downwardly. The cleaning member may be a mechanical or electro-mechanical member that taps, scrapes or otherwise engages the pre-motor filter to remove surface dirt therefrom. For example, a reciprocating motor with a hammer or the like provided on an arm extending therefrom may be utilized. The hammer may dislodge dirt from the upstream side when it contacts the pre-motor filter. Alternately, a weight, which is suspended on an arm at a position spaced from the pre-motor filter may be provided. Movement of the pre-motor filter may cause the weight to oscillate and engage repeatedly the pre-motor filter thereby assisting in cleaning the upstream side of the pre-motor filter. Alternately, one and more ribs or other scrapers may be provided abutting the upstream side and rotatably mounted so as to scrape the upstream surface thereby removing dirt therefrom. 
     It will be appreciated by a person skilled in the art that any of the features of the filter cleaning member disclosed herein need not be utilized with the uniflow cyclone design disclosed herein but may be used by itself or in combination with any other feature disclosed herein. 
     If a pre-motor filter is provided with a pre-motor filter dirt cup holder that receives dirt that accumulates on, or is dislodged from, the upstream side of the pre-motor filter, the surface cleaning apparatus may be constructed such that the pre-motor filter dirt cup may be emptied when the cyclone chamber and/or a dirt collection chamber in communication with the cyclone chamber is emptied. Preferably, the pre-motor filter dirt cup, the cyclone chamber and the dirt chamber in communication with the cyclone chamber are concurrently emptied. For example, all three dirt collection areas may have a common floor or wall which is openable. 
     The pre-motor filter dirt cup may comprise a chamber exterior to the cyclone chamber which is in communication with the upstream side of the pre-motor filter via an angled pathway (e.g., a ramp). For example, the upstream side of the pre-motor filter may face the air outlet end of the cyclone chamber so that the air exiting the cyclone chamber travels linearly to reach the pre-motor filter. An angled wall may be provided underneath the pre-motor filter and above the cyclone chamber so as to direct dirt to a dirt collection chamber adjacent, e.g., the sidewall of the cyclone chamber or the dirt collection chamber in communication with the cyclone chamber. The dirt cup and the cyclone chamber may have a common floor which is openable. In an alternate design, the upstream side of the pre-motor filter may face the vortex finder. A dirt collection chamber may be provided in an insert extending upwardly from the end wall of the cyclone chamber opposed to and facing the vortex finder. Accordingly, dirt may fall from the upstream side of the pre-motor filter and travel downwardly through the vortex finder to the pre-motor filter dirt collection chamber. In such a case, a filter cleaner as discussed previously may be provided and may engage the upstream side of the pre-motor filter. Accordingly, when a cyclone is not in use (e.g. the vacuum cleaner is turned off), the filter cleaning member may tap or otherwise physically agitate the pre-motor filter to loosen dirt which then falls downwardly through the vortex finder into the dirt collection chamber for the pre-motor filter. It will be appreciated that the dirt collection chamber for the premotor filter may be opened when the end wall of the cyclone chamber is opened so as to permit the cyclone chamber to be emptied. 
     It will be appreciated by a person skilled in the art that any of the features of the openable pre-motor filter dirt cup need not be utilized with the uniflow cyclone design disclosed herein but may be used by itself or in combination with any other feature disclosed herein. 
     Alternately, or in addition, it will be appreciated that the pre-motor filter dirt cup may be removable for emptying. The pre-motor filter dirt cup may be removable by itself, in combination with the cyclone chamber, in combination with the dirt chamber for the cyclone chamber or preferably, concurrently with both the cyclone chamber and the dirt collection chamber for the cyclone chamber. In particular, it is preferred that the dirt cup is removed with both the cyclone chamber and the dirt collection chamber and that all three are emptied at the same time. It will be appreciated by a person skilled in the art that any of the features of the removable pre-motor filter dirt cup need not be utilized with the uniflow cyclone design disclosed herein but may be used by itself or in combination with any other features disclosed herein. 
     In another embodiment, the surface cleaning apparatus may include an expandable hose which is biased to the extended position and is stored in a contracted position in the surface cleaning apparatus. An advantage of this design is that the suction hose may be stored in the surface cleaning apparatus and may be deployed when needed. For example, the hose may be stored in a compartment which has a hose outlet. One and more rollers, preferably at least a pair of opposed rollers or drive wheels, may be provided on opposed sides of the hose. The rollers may be manually and, preferably, electrically operated. Rotation of the rollers in one direction may allow the hose to be withdrawn from the chamber. Rotation of the rollers in the opposite direction may draw the hose automatically into the chamber for storage. In an alternate design, a ratchet type mechanism may be used. For example, a pair of pivotally mounted arms which are biased to an engagement position may be provided. The arms are positioned so as to contact the hose in an engaged position and prevent the hose from expanding and being drawn out of the chamber. If it is desired to remove the hose from the chamber, the arms may be moved to a disengaged position thereby allowing the hose to automatically extend itself due to the compression of the hose in the chamber. When it is desired to retract the hose into the chamber, the hose may be manually inserted, thereby compressing the hose in the chamber, or a pair of rollers or other motorized means may draw the hose into the chamber. It will be appreciated by a person skilled in the art that any of the features of a hose that is biased to an extended position need not be utilized with the uniflow cyclone design as disclosed herein but may be used by itself or in combination with any other feature disclosed herein. 
     In one embodiment, there is provided a surface cleaning apparatus comprising:
         (a) a cyclone chamber having a first end having a first end wall, a second end having a second end wall, an air inlet, an air outlet and a sidewall;   (b) an air flow path extending from a dirty air inlet to a clean air outlet and including a suction motor and the cyclone chamber; and,   (c) a pre-motor filter positioned in the air flow path downstream from the cyclone chamber and a pre-motor filter dirt chamber, wherein the pre-motor filter dirt chamber is openable.       

     In some embodiments, the surface cleaning apparatus may further comprise a dirt collection chamber in communication with a dirt outlet of the cyclone chamber wherein the pre-motor filter dirt chamber may be concurrently openable with the dirt collection chamber. 
     In some embodiments, the pre-motor filter dirt chamber and the dirt collection chamber may have a common door. 
     In some embodiments, the pre-motor filter dirt chamber may also be concurrently openable with the cyclone chamber. 
     In some embodiments, the cyclone chamber, the pre-motor filter dirt chamber and the dirt collection chamber may have a common door. 
     In some embodiments, the dirt collection chamber may be positioned exterior to the cyclone chamber. 
     In some embodiments, the pre-motor filter dirt chamber may be positioned exterior to the cyclone chamber. 
     In some embodiments, the pre-motor filter dirt chamber may also be positioned exterior to the dirt collection chamber. 
     In some embodiments, the pre-motor filter dirt chamber may be concurrently openable with the cyclone chamber. 
     In some embodiments, the cyclone chamber and the pre-motor filter dirt chamber may have a common door. 
     In some embodiments, the pre-motor filter dirt chamber may be positioned interior of the cyclone chamber. 
     In some embodiments, the wherein the pre-motor filter dirt chamber may be in communication with the pre-motor filter via the air outlet. 
     In some embodiments, the air outlet comprises a vortex finder, the pre-motor filter dirt chamber may be aligned with and spaced from the vortex finder to define an open area therebetween and a screen may enclose the open area. 
     In some embodiments, the pre-motor filter dirt chamber may extend inwardly from the first end wall and the vortex finder may extend inwardly from the second end wall and the air inlet may be provided at the first end. 
     In some embodiments, the surface cleaning apparatus may further comprise an agitation member operatively connected to the pre-motor filter. 
     In some embodiments, the agitation member may be actuated when the pre-motor filter dirt chamber is opened. 
     In some embodiments, the surface cleaning apparatus may further comprise a dirt collection chamber in communication with a dirt outlet of the cyclone chamber wherein the pre-motor filter dirt chamber may be removable from the surface cleaning apparatus with the dirt collection chamber. 
     In some embodiments, the pre-motor filter dirt chamber may also be removable with the cyclone chamber. 
     In some embodiments, the pre-motor filter dirt chamber may be removable from the surface cleaning apparatus with the cyclone chamber. 
     In some embodiments, the surface cleaning apparatus may further comprise an agitation member operatively connected to the pre-motor filter wherein the pre-motor filter dirt chamber may be removable from the surface cleaning apparatus and the agitation member may be actuated when the pre-motor filter dirt chamber is removed from the surface cleaning apparatus. 
     It will be appreciated by a person skilled in the art that a surface cleaning apparatus may embody any one or more of the features contained herein and that the features may be used in any particular combination or sub-combination. 
    
    
     
       DRAWINGS 
       The drawings included herewith are for illustrating various examples of articles, methods, and apparatuses of the teaching of the present specification and are not intended to limit the scope of what is taught in any way. 
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an embodiment of a surface cleaning apparatus; 
         FIG. 2  is a cross-sectional view of a portion of the surface cleaning apparatus of  FIG. 1 , taken along line F 2 -F 2  in  FIG. 1 ; 
         FIG. 3  is a perspective view of a portion of the surface cleaning apparatus of  FIG. 1 ; 
         FIG. 4  is a cross sectional view taken along line  4 F- 4 F in  FIG. 3 ; 
         FIG. 5  is a partially exploded perspective view of the surface cleaning apparatus of  FIG. 1 ; 
         FIG. 6  is a perspective view of a portion of the surface cleaning apparatus of  FIG. 1 ; 
         FIG. 7  is the perspective view of  FIG. 6  with a portion of the chassis portion removed; 
         FIG. 8  is a front perspective view of a cyclone bin assembly from the surface cleaning apparatus of  FIG. 1 ; 
         FIG. 9  is a rear perspective view of a cyclone bin assembly from the surface cleaning apparatus of  FIG. 1 ; 
         FIG. 10  is a bottom perspective view of a cyclone bin assembly from the surface cleaning apparatus of  FIG. 1  with the bin open; 
         FIG. 11  is a perspective cross sectional view taken along line  11 F- 11 F in  FIG. 8 ; 
         FIG. 12  is a top perspective view of a cyclone bin assembly from the surface cleaning apparatus of  FIG. 1  with the lid open and the pre-motor filters removed; 
         FIG. 13  is a side perspective view taken along line  11 F- 11 F in  FIG. 8 ; 
         FIG. 14  is a front perspective view of another embodiment of a cyclone bin assembly; 
         FIG. 15  is a perspective view of an alternate embodiment of a surface cleaning apparatus; 
         FIG. 16  is a cross sectional view taken along line F 16 -F 16  in  FIG. 15 ; 
         FIG. 17  is a schematic representation of an internal suction hose housing of the surface cleaning apparatus of  FIG. 16 ; 
         FIG. 18  is a schematic representation of another embodiment of a surface cleaning apparatus with an internal suction hose housing; 
         FIG. 19  is a schematic representation of another embodiment of an internal suction hose housing of a surface cleaning apparatus; 
         FIG. 20  is a perspective view of another embodiment of a surface cleaning apparatus; 
         FIG. 21  is an exploded perspective view of the surface cleaning apparatus of  FIG. 20 ; 
         FIG. 22  is a schematic representation of the surface cleaning apparatus of  FIG. 20 ; 
         FIG. 23  is a block diagram of an embodiment of a converter module; 
         FIG. 24  is a block diagram of another embodiment of a converter module; 
         FIG. 25  is a perspective view of the surface cleaning apparatus of  FIG. 1 ; 
         FIG. 26 a    is a partially exploded perspective view of the surface cleaning apparatus of  FIG. 20 ; 
         FIG. 26 b    is a schematic diagram of a cord reel control system; 
         FIG. 26 c    is a partially exploded perspective view of the surface cleaning apparatus of  FIG. 20  including a cord reel; 
         FIG. 26 d    is a partially exploded perspective view of an alternate embodiment of the surface cleaning apparatus of  FIG. 20  including a cord reel; 
         FIG. 27 a    is a partially exploded front perspective view of an embodiment of a cord reel; 
         FIGS. 27 b , 27 c , 27 d  and 28 a    are front perspective views of the cord reel of  FIG. 27   a;    
         FIG. 28 b    is a perspective view of an embodiment of a locating member; 
         FIG. 28 c    is a partially exploded front perspective view of the cord reel of  FIGS. 27 a , 27 b , 27 c , 27 d    and  28   a;    
         FIG. 29  is a front perspective view of the cord reel of  FIGS. 27 a -28 a    with a drive module removed; 
         FIGS. 30-31  are back perspective views of the cord reel of  FIGS. 27 a   - 28   a;    
         FIGS. 32-33  are perspective views of the cord reel of  FIGS. 27 a -28 a    in combination with a surface cleaning apparatus; 
         FIGS. 34-36  are front perspective views of another embodiment of a surface cleaning apparatus; 
         FIG. 37  is a perspective view from the front of another embodiment of a surface cleaning apparatus; 
         FIG. 38  is another perspective view from the rear of the surface cleaning apparatus of  FIG. 37 ; 
         FIG. 39  is a partially exploded perspective view of the surface cleaning apparatus of  FIG. 37 ; 
         FIG. 40  is a perspective view of a portion of the surface cleaning apparatus of  FIG. 37 ; 
         FIG. 41  is a cross sectional view of  FIG. 40 , taken along line  23 - 23  in  FIG. 40 ; 
         FIG. 42  is the cross sectional view of  FIG. 41  with a bottom door in an open position; 
         FIG. 43  is a bottom perspective view of the surface cleaning apparatus of  FIG. 37 ; 
         FIG. 44  is a cross sectional view of the surface cleaning apparatus of  FIG. 37 , taken along line  26 - 26  in  FIG. 37 ; 
         FIG. 45  is a cross sectional view taken along line  27 - 27  in  FIG. 37 ; 
         FIG. 46  is a perspective view of the surface cleaning apparatus of  FIG. 19  with a cover open; 
         FIG. 47  is the perspective view of  FIG. 46  with a filter cartridge removed; 
         FIG. 48  is the perspective view of  FIG. 47  with a filter removed from the filter cartridge; 
         FIG. 49  is a cross sectional view of a portion of another embodiment of a surface cleaning apparatus; 
         FIG. 50  is a cross sectional view of a portion of another embodiment of a surface cleaning apparatus; 
         FIG. 51  is the perspective view of  FIG. 47  with a different embodiment of a filter cartridge; 
         FIG. 52  is a cross sectional view of the filter cartridge taken along line  34 - 34  in  FIG. 51  with the filter cartridge in the surface cleaning apparatus; 
         FIG. 53  is a cross sectional view of another embodiment of a portion of a surface cleaning apparatus; 
         FIG. 54  is a cross sectional view of an alternate configuration of the portion of the surface cleaning apparatus of  FIG. 53 ; 
         FIG. 55  is a cross sectional view of another embodiment of a portion of a surface cleaning apparatus; and, 
         FIG. 56  is a cross sectional view of an alternate configuration of the portion of the surface cleaning apparatus of  FIG. 55 ; 
     
    
    
     DETAILED DESCRIPTION 
     Various apparatuses or processes will be described below to provide an example of an embodiment of each claimed invention. No embodiment described below limits any claimed invention and any claimed invention may cover processes or apparatuses that differ from those described below. The claimed inventions are not limited to apparatuses or processes having all of the features of any one apparatus or process described below or to features common to multiple or all of the apparatuses described below. It is possible that an apparatus or process described below is not an embodiment of any claimed invention. Any invention disclosed in an apparatus or process described below that is not claimed in this document may be the subject matter of another protective instrument, for example, a continuing patent application, and the applicants, inventors or owners do not intend to abandon, disclaim or dedicate to the public any such invention by its disclosure in this document. 
     General Description of a Canister Vacuum Cleaner 
     Referring to  FIG. 1 , a first embodiment of a surface cleaning apparatus  1  is shown. In the embodiment shown, the surface cleaning apparatus is a canister-type vacuum cleaner. In alternate embodiments, the surface cleaning apparatus may be another suitable type of surface cleaning apparatus, such as an upright-style vacuum cleaner, and hand vacuum cleaner, a stick vac, a wet-dry type vacuum cleaner, a carpet extractor or the like. 
     In the illustrated example, the surface cleaning apparatus  1  includes a chassis portion or support structure  2  and a surface cleaning head  3 . A surface cleaning unit  4  is mounted on the chassis portion  2 . The surface cleaning apparatus  1  also has at least one dirty air inlet  5 , at least one clean air outlet  6 , and an air flow path or passage extending therebetween. In the illustrated example, the air flow path includes at least one flexible air flow conduit member (such as a hose  7  or other flexible conduit). Alternatively, the air flow path may be formed from rigid members. 
     At least one suction motor and at least one air treatment member are positioned in the air flow path to separate dirt and other debris from the airflow. Preferably, the chassis portion and/or surface cleaning unit include the suction motor, to draw dirty air in through the dirty air inlet, and the air treatment member to remove dirt or debris from the dirty air flow. The air treatment member may be any suitable air treatment member, including, for example, one or more cyclones, filters, and bags. Preferably at least one air treatment member is provided upstream from the suction motor. Referring to  FIGS. 2 and 3 , in the illustrated example, the surface cleaning unit includes both the suction motor  8 , in a motor housing  12  and an air treatment member in the form of a cyclone bin assembly  9 . The motor housing can include at least one removable or openable door or grill  13  which may allow a user to access the interior of the motor housing  12 , for example to access the motor  8 , a post motor filter (e.g., a HEPA filter) or any other component within the housing  12 . Preferably, as exemplified in  FIG. 10 , a cyclone bin assembly  9  is provided wherein the cyclone bin assembly comprises a cyclone chamber  10  and a dirt collection chamber  11 . 
     Optionally, the surface cleaning unit  4  may be a portable surface cleaning unit and may be detachable from the chassis portion ( FIG. 3 ). In such embodiments, the surface cleaning unit  4  includes a suction motor and is removably mounted to chassis portion  2 . For example, chassis portion  2  may be connected to surface cleaning unit  4  by a mount apparatus  14  that allows the surface cleaning unit  4  to be detached from the chassis portion  2 . Preferably, mount apparatus is has a release actuator that is foot operable, such as a foot pedal. The foot pedal may be lined electrically or mechanically to a surface cleaning unit engagement member, which may comprise one or more engagement members configured to engage and retain surface cleaning unit  4  in position on chassis portion  2 . For example, referring to  FIGS. 6 and 7 , in the illustrated embodiment the mount apparatus  14  includes a foot pedal  145  that is connected to rear latch  146  and to front latch  147  via a connecting rod  148 . The rear latch  146  engages a rear slot  149  on the surface cleaning unit  4 , and the front latch  147  engages a corresponding front slot  150 . Stepping on the pedal  145  can disengage both latches  146 ,  147 , thereby releasing the surface cleaning unit  4  from the chassis portion  2 . The latches  146 ,  147  and pedal  145  can be biased toward the latched configuration. Optionally, a cavity  152  for storing an auxiliary cleaning tool  153  may be formed at the interface between the surface cleaning unit  4  and the chassis  2  and preferably comprises a recess in the lower surface of the surface cleaning unit  4 . 
     In the embodiment shown, the surface cleaning head  3  includes the dirty air inlet  5  in the form of a slot or opening formed in a generally downward facing surface of the surface cleaning head  3 . From the dirty air inlet  5 , the air flow path extends through the surface cleaning head  3 , and through an up flow conduit  16  ( FIG. 2 ) in the chassis portion  2  to the surface cleaning unit  4 . In the illustrated example, the clean air outlet  6  is provided in the rear of the surface cleaning unit  4 , and is configured to direct the clear air in a generally lateral direction, toward the back of the apparatus  1 . 
     A handle  17  is provided toward the top of the up flow conduit  16  to allow a user to manipulate the surface cleaning head  3 . Referring to  FIGS. 1 and 3 , the up flow conduit  16  extends along an upper axis  18  and is moveably mounted to the surface cleaning head  3 . In the illustrated example, the up flow conduit  16  is pivotally mounted to the surface cleaning head via a pivot joint  19 . The pivot joint  19  may be any suitable pivot joint. Alternatively, or in addition to being pivotally coupled to the surface cleaning head, the up flow conduit  16  can also be rotatably mounted to the surface cleaning head. In this configuration, the up flow conduit  16  may be rotatable about the upper axis. In this configuration, rotation of the up flow conduit  16  about the upper axis may help steer the surface cleaning head across the floor (or other surface being cleaned). It will be appreciated that the surface cleaning head  3  and conduit  16  may be of any design known in the art and the air flow path to the surface cleaning unit  4  may be of any design. 
     Portable Cleaning Mode 
     In one aspect of the teachings described herein, which may be used in combination with any one or more other aspects, the vacuum cleaner  1  may be operable in a variety different functional configurations or operating modes. The versatility of operating in different operating modes may be achieved by permitting the surface cleaning unit to be detachable from the chassis portion. Alternatively, or in addition, further versatility may be achieved by permitting portions of the vacuum cleaner to be detachable from each other at a plurality of locations in the chassis portion, and re-connectable to each other in a variety of combinations and configurations. 
     In the example illustrated, mounting the surface cleaning unit  4  on the chassis portion  2  allows the chassis portion  2  to carry the weight of the surface cleaning unit  4  and to, e.g., rollingly support the weight using rear wheels  100  and front wheel  101  ( FIG. 2 ). With the surface cleaning unit  4  attached, the vacuum cleaner  1  may be operated like a traditional canister-style vacuum cleaner. 
     Alternatively, in some cleaning situations the user may preferably detach the surface cleaning unit  4  from the chassis portion  2  and choose to carry the surface cleaning unit  4  (e.g. by hand or by a strap) separately from the chassis portion  2 , while still using the up flow conduit  16  to drivingly maneuver the surface cleaning head  3 . When the surface cleaning unit  4  is detached, a user may more easily maneuver the surface cleaning head and the cleaning unit  4  around obstacles, like furniture and stairs. 
     To enable the vacuum suction generated by the surface cleaning unit  4  to reach the surface cleaning head  3  when the surface cleaning unit  4  is detached from the support structure  2 , the airflow connection between the surface cleaning head  3  and the cleaning unit  4  is preferably at least partially formed by a flexible conduit, such as the flexible hose  7 . The flexible conduit is preferably attached to the surface cleaning unit  4  and not chassis  2  so as to allow a user to detach the surface cleaning unit  4  and maintain a flow connection between the portable surface cleaning unit  4  and the surface cleaning head  3  without having to reconfigure or reconnect any portions of the airflow conduit  16  ( FIG. 5 ). 
     Referring to  FIG. 5 , when the surface cleaning apparatus  1  is in use, a user may detach the surface cleaning unit  4  from the chassis portion  2  without interrupting the airflow communication between the cleaning unit  4  and the surface cleaning head  3 . This allows a user to selectively detach and re-attach the cleaning unit  4  to the support structure  2  during use without having to stop and reconfigure the connecting hoses  7  or other portions of the airflow conduit  16 . 
     Removable Cyclone Bin Assembly 
     The following is a description of a removable cyclone bin assembly that may be used by itself in any surface cleaning apparatus or in any combination or sub-combination with any other feature or features disclosed herein. 
     Optionally, the cyclone bin assembly  9  can be detachable from the motor housing  12 . Providing a detachable cyclone bin assembly  9  may allow a user to carry the cyclone bin assembly  9  to a garbage can for emptying, without needing to carry or move the rest of the surface cleaning apparatus  1 . Preferably, the cyclone bin assembly  9  can be separated from the motor housing  12  while the surface cleaning unit  4  is mounted on the chassis portion  2  and also when the surface cleaning unit  4  is separated from the chassis portion  2 . Accordingly, the cyclone bin assembly is preferably positioned on an upper portion of the surface cleaning unit  4  and may be mounted on a shelf or recess provided forwardly of the suction motor. 
     Preferably, as exemplified in  FIG. 3 , the cyclone bin assembly  9  is removable as a closed module, which may help prevent dirt and debris from spilling out of the cyclone bin assembly  9  during transport. 
     In the illustrated example, the cyclone bin assembly  9  includes an outer sidewall  35  and a lid  36 . The lid  36  is openable, and in the illustrated embodiment is pivotally connected to the sidewall  35  by hinges  102  ( FIG. 9 ) and pivotal between an open position ( FIG. 12 ) and a closed position ( FIG. 9 ). The lid  36  can be held in its closed position using any suitable closure member, such as releasable latch  103 . 
     In the illustrated embodiment, a bin handle  37  is provided on the lid  36 . The bin handle  37  may allow a user to carry the surface cleaning unit  4  when it is detached from the chassis portion  2 , and preferably is removable from the suction motor housing  12  with the cyclone bin assembly  9  so that it can also be used to carry the cyclone bin assembly for emptying. 
     Cyclone Construction 
     The following is a description of a cyclone construction that may be used by itself in any surface cleaning apparatus or in any combination or sub-combination with any other feature or features disclosed herein. 
     Referring to  FIGS. 11 and 13  in the illustrated embodiment the cyclone chamber  10  extends along a cyclone axis  38  and includes a first end wall  39 , a second end wall  40  axially spaced apart from the first end wall  39  and a generally cylindrical sidewall  41  extending between the first and second end walls  39 ,  40 . Optionally, some or all of the cyclone walls can coincide with portions of the dirt collection chamber  11  walls, suction motor housing  12  walls and/or may form portions of the outer surface  35  of surface cleaning unit. Alternatively, in some examples some or all of the cyclone walls can be distinct from other portions of the surface cleaning unit. In the illustrated embodiment, the cyclone chamber  10  is arranged in a generally vertical, uniflow cyclone configuration. Alternatively, the cyclone chamber can be provided in another configuration, including, having at least one or both of the air inlet and air outlet positioned toward the top of the cyclone chamber, or as a horizontal or inclined cyclone. 
     In the illustrated embodiment, the cyclone chamber  10  includes a cyclone air inlet  42  in fluid communication with a cyclone air outlet  43 . The cyclone chamber  10  also includes at least one dirt outlet  44  (see also  FIG. 10 ), through which dirt and debris that is separated from the air flow can exit the cyclone chamber  10 . While it is preferred that most or all of the dirt exit the cyclone chamber via the dirt outlet, some dirt may settle on the bottom end wall  40  of the cyclone chamber  10  and/or may be carried with the air exiting the cyclone chamber via the air outlet  43 . 
     Preferably the cyclone air inlet  42  is located toward one end of the cyclone chamber  10  (the lower end in the example illustrated) and may be positioned adjacent the corresponding cyclone chamber end wall  40 . Alternatively, the cyclone air inlet  42  may be provided at another location within the cyclone chamber  10 . 
     Referring to  FIG. 11 , in the illustrated embodiment the air inlet  42  includes an upstream or inlet end  45 , which may be coupled to the hose  7  or other suitable conduit, and a downstream end  46  ( FIG. 10 ) that is spaced apart from the upstream end  45 . In the illustrated configuration, the cyclone bin assembly  9  can be removed from the surface cleaning unit  4 , for example, for cleaning or emptying, while the hose  7  remains with the surface cleaning unit  4 . This may allow a user to remove the cyclone bin  9  assembly without having to detach or decouple the hose  7 . Alternatively, the downstream end of the hose  7  may be coupled to the cyclone bin assembly  9  such that the downstream end of the hose travels with the cyclone bin assembly when it is removed. 
     The air inlet  42  defines an inlet axis  47  and has an inlet diameter  48  ( FIG. 13 ). The cross-sectional area of the air inlet  42  taken in a plane orthogonal to the inlet axis  47  can be referred to as the cross-sectional area or flow area of the air inlet  42 . Preferably, the air inlet  42  is positioned so that air flowing out of the downstream end is travelling generally tangentially relative to the sidewall  41  of the cyclone chamber  10 . 
     The perimeter of the air inlet  42  defines a cross-sectional shape of the air inlet. The cross-sectional shape of the air inlet can be any suitable shape. In the illustrated example the air inlet has a generally round/circular cross-sectional shape with radius  48 . Optionally, the diameter  48  may be between about 0.25 inches and about 5 inches or more, preferably between about 1 inch and about 5 inches, more preferably is between about 0.75 and 2 inches or between about 1.5 inches and about 3 inches, and most preferably is about 2 to 2.5 inches or between about 1 to 1.5 inches. Alternatively, instead of being circular, the cross-sectional shape of the air inlet may be another shape, including, for example, oval, square and rectangular. 
     Air can exit the cyclone chamber  10  via the air outlet  43 . Optionally, the cyclone air outlet  43  may be positioned in one of the cyclone chamber end walls, and in the example illustrated is positioned in the end wall  39 , at the opposite end of the cyclone chamber  10  from the air inlet  42 . In this configuration, air can enter at the bottom of the cyclone chamber  10  and exit at the upper end of the cyclone chamber  10 . 
     In the illustrated example, the cyclone air outlet  43  includes a vortex finder  49 . In the example illustrated, the longitudinal cyclone axis  38  is aligned with the orientation of the vortex finder  49 . In the illustrated embodiment the air outlet  43  is generally circular in cross-sectional shape and defines an air outlet diameter  51  ( FIG. 21 ). Optionally, the cross-sectional or flow area of the cyclone air outlet  43  may be between about 50% and about 150% and between about 60%-90% and about 70%-80% of the cross-sectional area of the cyclone air inlet  42 , and preferable is generally equal to the cyclone air inlet area. In this configuration, the air outlet diameter  51  may be about the same as the air inlet diameter  48 . 
     Referring to  FIG. 11 , in the illustrated embodiment, the upper end wall  39  is connected to the upper end of the sidewall  41  to enclose the upper end of the cyclone chamber  10 . In the illustrated example, the intersection or juncture  64  between the end wall  39  and the side wall  41  is a relatively sharp corner that does not include any type of angled or radiused surface. Similarly, in the illustrated embodiment, the lower end wall  40  meets the lower end of the cyclone sidewall  41  at a juncture  65  that is also configured as a relatively sharp corner. 
     Optionally, the juncture between the vortex finder  49  and the end wall  39  may be provided with an angled or curved surface. In the illustrated embodiment, the juncture  70  between the end wall  40  and the vortex finder  49  includes a curved surface  72  ( FIG. 13 ). The curved surface  72  has a radius  71 . The radius  71  may be selected based on the radius of the air inlet  42  (e.g. half of the diameter  48 ), and optionally may be the selected so that the juncture surface  72  has the same radius as the air inlet  42 . Providing curved surface  72  at the juncture  70  may help reduce backpressure and may help improve cyclone efficiency. 
     Referring to  FIG. 11 , in the illustrated embodiment the cyclone is a uniflow cyclone and an extension member  77  extends inwardly from a lower end wall of the cyclone chamber and may extend to a position that is proximate the lower end  105  of the screen  50  and may abut lower end  105 . The extension member  77  may be a closed member or, alternately, it may be a generally hollow tube-like member that extends between the lower end  105  of the screen  50  and the end wall  40  so as to provide a pre-motor filter dirt cup as discussed subsequently. Together, the vortex finder  49 , screen  50  and extension member  77  may form a generally continuous internal column member that extends between the first and second end walls  39  and  40  of the cyclone chamber  10 . Providing the projection member  77  may help direct air flow within the cyclone chamber, and may help support and/or stabilize the distal end  78  of the screen  50 . 
     Optionally, the juncture  79  between the end wall  40  and the projection member  77  may include a curved or angled juncture surface, similar to surface  72 , or may be provided as a sharp corner as illustrated. 
     In the illustrated embodiment the extension member  77  is integral with the screen  50  and vortex finder  49 , and remains within the cyclone chamber  10  when the door  63  is opened. Alternatively, some or all of the extension member  77 , screen  50  and vortex finder  49  may be mounted to the end wall  40 , such that they move with the door  63  and is removed from the cyclone chamber  10  when the door  63  is opened. 
     In the illustrated embodiment, the air inlet  42  is positioned at the juncture  65  between the sidewall  41  and the end wall  40  and is positioned such that the air inlet  42  is adjacent the sidewall  41  and the end wall  40  (i.e. there is no radial gap between the outer edge of the air inlet  42  and the sidewall  41  and no axial gap between the bottom of the air inlet  42  and the end wall  40 ). Alternatively, the air inlet  42  may be spaced radially inwardly from the sidewall  41  or axially above the end wall  40 . 
     When combined with any other embodiment, the cyclone bin assembly  9  may be of any particular design and may use any number of cyclone chambers and dirt collection chambers. The following is a description of exemplified features of a cyclone bin assembly any of which may be used either individually or in any combination or sub-combination with any other feature disclosed herein. 
     Screen 
     The following is a description of a cyclone and a screen that may be used by itself in any surface cleaning apparatus or in any combination or sub-combination with any other feature or features disclosed herein. 
     Optionally, a screen or other type of filter member may be provided on the cyclone air outlet  43  to help prevent fluff, lint and other debris from exiting via the air outlet. Referring to  FIG. 11 , in the illustrated example a screen  50  is positioned at the air outlet  43  and connected to the vortex finder  49 . In  FIG. 11  the screen is illustrated with a representation of its mesh in place, however for clarity the mesh has been omitted from the other Figures. The screen  50  is generally cylindrical in the illustrated embodiment, but may be of any suitable shape, including for example frusto-conical, in other embodiments. Optionally, the screen  50  can be removable from the vortex finder  49 . 
     Optionally, the screen  50  may be sized to have a cross-section area that is larger than, smaller than or generally equal to the air outlet  43  cross-sectional area. Referring to  FIG. 13 , in the illustrated example, the diameter  52  of the screen  50  is less than the diameter  51  of the vortex finder  49  conduit providing the cyclone air outlet  43 . In this configuration, the radial surface  53  of the screen  50  is radially offset inwardly from the surface  54  of the vortex finder  49  by an offset distance  55 . Providing the offset gap  55  between the surfaces  53 ,  54  of the screen  50  and vortex finder  49  may help provide a relatively calmer region (i.e. a region of reduced air flow turbulence and/or laminar air flow) within the cyclone chamber  10 . It may also assist the air that has been treated in the cyclone chamber to travel towards the vortex finder while mixing less with the air entering the cyclone chamber via the air inlet and thereby reduce the likelihood of dirt bypassing treatment in the cyclone chamber and travelling directly to the air outlet. Providing a relatively calmer air flow region adjacent the surface  53  of the screen  50  may help enable air to more easily flow through the screen  50  and into the vortex finder  49 , which may help reduce backpressure in the air flow path. Reducing back pressure may help improve the efficiency of the cyclone chamber and/or may help reduce power requirements for generating and/or maintaining a desired level of suction. 
     In the illustrated embodiment the screen  50  is of generally constant diameter. Alternatively, the diameter of the screen  50  may vary along its length. For example, the screen may be generally tapered and may narrow toward its upper end (i.e. the end that is spaced apart from the vortex finder  49 ). The cross sectional area of the inner end of the screen may be 60-90% the cross sectional area of the air inlet and preferably is 70-80% the cross sectional area of the air inlet. 
     The screen may be tapered such that the width at the base of the screen (adjacent the vortex finder) is greater than the width at the upper end of the screen. In this configuration the cross-sectional area of the screen (in a plane that is generally perpendicular to the screen  50 ) is greater at the base of the screen than at its upper end. The amount of taper on the screen may be any suitable amount, and for example may be selected so that the cross-sectional area at the upper end of the screen is between about 60% and 90%, between about 70% and 80% and may be about 63%-67% of the cross-sectional area of the base of the screen. 
     Dirt Outlet 
     The following is a description of a cyclone dirt outlet that may be used by itself in any surface cleaning apparatus or in any combination or sub-combination with any other feature or features disclosed herein. 
     Cyclone chamber  10  may be in communication with a dirt collection chamber by any suitable means. Preferably, as exemplified, the dirt collection chamber  11  is exterior to cyclone chamber  10 , and preferably has a sidewall  56  at least partially or completely laterally surrounds the cyclone chamber  10 . At least partially nesting the cyclone chamber  10  within the dirt collection chamber  11  may help reduce the overall size of the cyclone bin assembly. Referring to  FIG. 2 , in the illustrated embodiment the cyclone chamber sidewall  41  is coincident with the sidewall  56  for approximately half its circumference. It will be appreciated that the dirt collection chamber may fully surround the cyclone chamber. 
     In the illustrated embodiment, the dirt outlet  44  is in communication with the cyclone chamber  10  and the dirt collection chamber  11 . Optionally, the dirt outlet  44  can be axially and/or angularly spaced from the cyclone air inlet. Preferably, the cyclone dirt outlet  44  is positioned toward the opposite end of the cyclone chamber  10  from the cyclone air inlet  42 . The cyclone dirt outlet  44  may be any type of opening and may be in communication with the dirt collection chamber to allow dirt and debris to exit the cyclone chamber  10  and enter the dirt collection chamber  11 . 
     In the illustrated example, the cyclone dirt outlet  44  is in the form of a slot bounded by the cyclone side wall  41  and the upper cyclone end wall  39 , and is located toward the upper end of the cyclone chamber  10 . Alternatively, in other embodiments, the dirt outlet may be of any other suitable configuration, and may be provided at another location in the cyclone chamber, including, for example as an annular gap between the sidewall and an end wall of the cyclone chamber or an arrestor plate or other suitable member. If the dirt outlet comprises an annular gap, then a cut out may be provided in the end of the sidewall of the cyclone chamber facing the end wall of the plate so that part of the sidewall may be further from the plate or end wall than the rest of the sidewall. 
     In a preferred embodiment, a cyclone chamber comprises a uniflow cyclone with a dirt outlet at the air outlet end. Preferably, the dirt outlet is a slot shaped dirt outlet and more preferably, the end wall abuts the sidewall of the cyclone chamber except at the location of the dirt outlet. In such a case, the air outlet or vortex finder preferably extends into the cyclone chamber further than the edge of the dirt outlet that is spaced furthest from the end wall. 
     Referring to  FIG. 13 , the dirt slot  44  may be of any suitable length  57 , generally measured in the axial direction, and may be between about 0.1 inches and about 2 inches, or more. Optionally, the length  57  of the slot  44  may be constant along its width, or alternatively the length  57  may vary along the width of the slot  44 , preferably in the downstream direction as measured by the direction of air rotation in the cyclone chamber. 
     Optionally, the slot  44  may extend around the entire perimeter of the cyclone chamber (forming a generally continuous annular gap) or may extend around only a portion of the cyclone chamber perimeter. For example, the slot may subtend an angle  73  ( FIG. 10 ) that is between about 5° and about 360°, and may be between about 5-150°, about 15-120°, about 35-75°, about 45 and about 90° and between about 60 and 80°. Similarly, the slot  44  may extend around about 10% to about 80% of the cyclone chamber perimeter, and preferably may extend around about 15% to about 40% of the cyclone chamber perimeter. 
     Optionally, the slot  44  may be positioned so that it is angularly aligned with the cyclone air inlet  42 , or so that an angle  60  ( FIG. 10 ) between the air inlet and the slot  44  (measured to a center line of the slot  44 ) is between about 0 and about 350° or more, and may be between 5° and about 180° and may be between about 0 and about 90°. In some embodiments, the slot  44  can be positioned so that an upstream end of the slot (i.e. the end of the slot that is upstream relative to the direction of the air circulating within the cyclone chamber) is between about 0° and about 350° from the air inlet, and may be between about 5 and 180° and between about 0-90°, about 0-45° and about 0-15° downstream from the air inlet. 
     The dirt collection chamber  11  may be of any suitable configuration. Referring to  FIG. 10 , in the illustrated example, the dirt collection chamber  11  includes a first end wall  61 , a second end wall  62  and the sidewall  56  extending therebetween. 
     To help facilitate emptying the dirt collection chamber  11 , one of or both of the end walls  61 ,  62  may be openable. Similarly, one or both of the cyclone chamber end walls  39  and  40  may be openable to allow a user to empty debris from the cyclone chamber. In the illustrated example, the upper dirt chamber end wall  61  is integral with the upper cyclone end wall  39  and the lower dirt collection chamber end wall  62  is integral with, and openable with, the lower cyclone chamber end wall  40  and both form part of the openable bottom door  63 . The door  63  is moveable between a closed position ( FIG. 11 ) and an open position ( FIG. 10 ). When the door  63  is open, both the cyclone chamber  10  and the dirt collection chamber  11  can be emptied concurrently. Alternatively, the end walls of the dirt collection chamber  11  and the cyclone chamber  10  need not be integral with each other, and the dirt collection chamber  11  may be openable independently of the cyclone chamber  10 . 
     Pre-Motor Filter Housing 
     The following is a description of a pre-motor filter housing that may be used by itself in any surface cleaning apparatus or in any combination or sub-combination with any other feature or features disclosed herein. 
     Referring to  FIG. 12 , in the illustrated embodiment, the cyclone bin assembly  9  includes a pre-motor filter chamber  31  that is positioned in the air flow path between the cyclone chamber  10  and the suction motor  8  (see also  FIG. 11 ). One or more filters can be provided in the pre-motor filter chamber  31  to filter the air exiting the cyclone bin assembly  9  before it reaches the motor  8 . Preferably, as exemplified, the pre-motor filter includes a foam filter  32  and a downstream felt layer  33  positioned within the pre-motor filter chamber  31 . Preferably, the filters  32 ,  33  are removable ( FIG. 12 ) to allow a user to clean and/or replace them when they are dirty. 
     Referring to  FIG. 12 , the pre-motor filter chamber  31  includes an upper end wall  110 , a sidewall  111  and a lower end wall  112 . Optionally, the sidewalls  111  of the pre-motor filter chamber  31  can be at least partially transparent so that a user can visually inspect the condition of the filters  32 ,  33  to determine if they require cleaning or replacement without having to remove the cyclone bin assembly  9 . 
     The open headspace or header between the upper end wall  39  of the cyclone chamber  10  and the upstream side  123  of the filter  32  defines an upstream air plenum  124  (see  FIG. 13 ). Providing the upstream plenum  124  allows air to flow across the upstream side  123  of the filter  32 . The open headspace or header downstream of the filters  32 ,  33 , between the downstream side  125  of filter  33  and the upper wall  110 , provides a downstream air plenum  126 . Providing a downstream plenum  126  allows air exiting the filters  32 ,  33  to flow radially across the downstream side  125  of filter  33  and toward the pre-motor filter chamber air outlet  135 . In use, air exits the cyclone chamber  10  via the air outlet  43  and flows into upstream plenum  124 , through filters  32 ,  33 , into downstream plenum  126  and into the air outlet  135  of the pre-motor filter housing. 
     In the illustrated embodiment, the air outlet  135  is provided in the lid  36  and has an inlet end  136  in the pre-motor filter chamber ( FIG. 12 ) and an outlet end  137  provided on the outer surface of the cyclone bin assembly ( FIGS. 10 and 4 ). To provide air flow communication between the pre-motor filter chamber  31  and the suction motor  8 , the outlet end  137  is configured to mate with the inlet end  138  of a motor air flow passage  139  provided in the surface cleaning unit  4 . The motor air flow passage  139  is in air flow communication with the air inlet  113  of the suction motor  8 . 
     Referring to  FIG. 12 , most of the upper end wall  110  and sidewall  111  may be provided by the inner surface of the lid  36 , which may be opened to provide access to the filters  32 ,  32 . In the illustrated embodiment, opening the lid  36  exposes the downstream side  125  of filter  33 , which is generally the cleaner side of the pre-motor filter. Configuring the pre-motor filter chamber so that the clean, downstream side of the filter is exposed to the user when the lid  36  is opened allows a user to grasp the clean side  125  of the filter  33 . This may allow the user to remove or manipulate the filter  33  while holding its clean side  125 , and may eliminate the need for a user to grasp or otherwise contact the relatively dirtier, upstream side of the filter. 
     Optionally, filter  33  may be connected to filter  32  so that a user grasping the clean side  125  may be able to remove both filters  32 ,  33 . Alternatively, the filter  33  may be removable independently from the filter  32 . In such a configuration, removing the filter  33  will expose the downstream side  140  of the filter  32 . While potentially not as clear as surface  125 , the downstream side  140  of filter  32  is likely to be cleaner than upstream side  123 . In this configuration, a user can grasp filter  32  via downstream side  140  and can avoid having to touch or otherwise contact the dirtier upstream side  123 . 
     Optionally, some or all of the intersections between the vortex finder and wall  110 , the walls  110  and  111 , the walls  111  and  112 , and the wall  112  and the pre-motor filter air outlet  135  may include angled or curved surfaces, for example like the surfaces within the cyclone chamber  10 . Providing curved or smooth junctures within the pre-motor filter housing  31  may help improve air flow and may reduce backpressure in the air flow path. This may help improve the efficiency of the surface cleaning apparatus  1 . Improving the efficiency may allow the surface cleaning apparatus to provide improved suction capabilities, and/or may allow the surface cleaning apparatus to maintain its existing suction capabilities while requiring a smaller, less powerful motor  8 . 
     In the illustrated example, the bottom wall  112  includes a plurality of supporting ribs  130  that project upwards from the wall  112  into the chamber  31 . The ribs  130  are configured to contact the upstream side  123  of the filters (in this example felt filter  32 ) in the chamber  31  and to hold it above the wall  112 , thereby help to maintaining the downstream plenum  126 . The ribs  130  are spaced apart from each other to allow air to flow between them, within the plenum  126 , and toward the suction motor air inlet  113 . In the illustrated embodiment, the upper wall  110  also includes a plurality of ribs  130  for contacting the upstream side  125  of the filters (in this example filter  33 ) and to maintain a spacing between the upstream side  125  and the wall  110  to provide the upstream plenum  126 . 
     Optionally, some or all of the support ribs in the pre-motor filter chamber  31  may be configured to help guide or direct the air flowing through the downstream plenum  126 . For example, some of the ribs may be configured to help induce rotation of the air within the plenum  126 , before it flows into the suction motor  8 . Preferably, this pre-rotation of the air flow can be selected so that the air is rotated in the direction of revolution of the suction motor  8 . Pre-rotating the air in this manner may help improve the efficiency of the surface cleaning unit  4 . The ribs may be configured in any suitable manner to help impart rotation to the air flow. 
     The ribs  130  define a rib height  133 . If the lower wall  112  of the pre-motor filter is flat, the height  133  of each rib  130 ,  131  may remain constant along its entire with. Alternatively, if the lower wall  112  varies in height, (e.g., the ribs extend to a trumpet shaped portion of a vortex finder, then the ribs  130 ,  131  may also vary in height so as to provide a planar support surface for the filter. Preferably, the ribs  130 ,  131  are configured such that the upper ends of the ribs  130 ,  131  lie in a common plane to support the filter  33 , and the lower ends of the ribs are in contact with the wall  112 . 
     Pre-Motor Filter Dirt Chamber and Filter Cleaning Member 
     The following is a description of a pre-motor filter dirt chamber and a filter cleaning member, each of which may be used separately or together in any surface cleaning apparatus or in any combination or sub-combination with any other feature or features disclosed herein. 
     When the surface cleaning apparatus  1  is in use the upstream side  123  of the filter  32  may become soiled and/or partially blocked by dust and other relatively fine debris that is carried out of the cyclone chamber  10 . If the upstream side  123  of the filter  32  becomes sufficiently blocked, air flow through filter  32  may be compromised and efficiency of the surface cleaning apparatus  1  may decrease. One method of cleaning the upstream side  123  of the filter  32  is for a user to remove the filter  32  as described above, clean the surface  123  and replace the filter  32  within the pre-motor filter chamber  31 . Optionally, instead of cleaning the filter  32 , a user may insert a new filter. Alternatively, instead of removing the filter  32  from the pre-motor filter chamber  31 , the surface cleaning apparatus  1  may be configured to allow the filter  32 , particularly the upstream side  123 , to be cleaned in situ, without removing the filter  32  from the pre-motor filter chamber  31 . Dirt and debris may be extracted from the upstream side  123  using any suitable mechanism, including, for example, banging to tapping one or more sides of the pre-motor filter chamber  31  and/or the pre-motor filter to dislodge the dirt and using a mechanical and/or electro-mechanical mechanism to help dislodge the debris. Examples of such mechanisms may include, for example, a scraper or other mechanical member that contacts and cleans the surface  123  and a shaker or beater type of mechanism that can shake the filter  32  to help dislodge the debris. 
     Alternately, or in addition, the pre-motor filter chamber  31  may be configured to receive fine dirt and debris from the upstream side  123  and direct the debris into a fine particle collection chamber or pre-motor filter dirt chamber that can collect the dislodged debris. The fine particle collection chamber may be a portion of the primary dirt collection chamber  11 , or may be provided as a separate chamber. The fine particle collection chamber may be positioned directly below the upstream side of the pre-motor filter so that dirt falls downwardly into the chamber or it may be laterally spaced so that the dirt is conveyed laterally, e.g., by a ramp or an angled surface, to the chamber. 
     Referring to  FIG. 13 , in the illustrated embodiment, the cyclone bin assembly  9  includes a pre-motor filter dirt chamber  140  for receiving debris  141  that is dislodged from the upstream upside  123  of filter  32 . In the illustrated embodiment, the dirt chamber  140  is located within the extension member  77 , which is inside the cyclone chamber  10 . In this configuration, there is no communication between the dirt chamber  140  and the dirt chamber  11 , nor do they share any walls or components in common. Alternatively, the dirt chamber  140  may be nested within the dirt chamber  11  and/or may have one or more surfaces or walls in common with the dirt chamber  11 . 
     In the illustrated example, the bottom wall  112  of the pre-motor filter chamber  31  (which is coincident with the upper wall  39  of the cyclone chamber  10  in this example) is curved downwardly toward the air inlet  43 . Curving the wall  112  in this manner may help guide the debris toward the air outlet  43 . When the air flow through the cyclone chamber  10  is off (i.e. when the cyclone bin assembly  9  is removed and/or when the surface cleaning apparatus is off), the debris  141  on wall  112  may fall downwardly though the vortex finder  39 , through the air outlet, pass through the interior of the screen  50  and fall into the dirt chamber  140 . Because the dirt chamber  140  is positioned below the air flow openings in the screen  50  it may be a relatively low air flow region when the surface cleaning apparatus is in use. This may allow debris  141  that has accumulated in dirt chamber  140  to remain in the dirt chamber  140  if the surface cleaning apparatus  1  is used prior to emptying the dirt chamber  140 , as the debris  141  in chamber  140  will tend not to be re-entrained in the air flowing into the screen  50  and upwardly though the air outlet  43 . 
     The dirt chamber  140  includes a sidewall  142  and a bottom wall  143 . The top of the chamber  140  is open to receive the debris  141 . Referring to  FIG. 10 , in the illustrated embodiment the lower end of the dirt chamber  140  is integral with the floor  40  of the cyclone chamber and is part of the openable door  63 . In this configuration, the pre-motor filter dirt chamber  140  is contained within the cyclone bin assembly  9 , and is therefore removable from the surface cleaning unit  4  with the cyclone chamber  10 , dirt chamber  11  and pre-motor filter chamber  31  for emptying and/or cleaning. Preferably, as illustrated, the dirt chamber  140  can be removed in its closed configuration to help prevent dirt and debris from spilling when the cyclone bin assembly  9  is manipulated. 
     In this configuration, opening the door  63  simultaneously opens the cyclone chamber  10 , the dirt chamber  11  and the pre-motor filter dirt chamber  140 . Alternatively, the pre-motor filter chamber  140  can be configured so that it is openable in combination with only one of the cyclone chamber  10  and/or dirt collection chamber  11 , or independently from any other chamber. 
     For example, referring to  FIG. 14  the cyclone bin assembly  9  can include a modified bottom door  63  that includes two separately openable portions  63   a  and  63   b  that are pivotally mounted about hinge  63   c . Each door portion  63   a ,  63   b  can be held closed by a corresponding, releasable latch  151   a  and  151   b  (similar to latch  151  that holds the door  63  closed). In this configuration, the dirt chamber  11  can be emptied independently of the cyclone chamber  10  and dirt chamber  140 . 
     It will also be appreciated that the pre-motor filter chamber  140  may be removable in combination with only one of the cyclone chamber  10  and/or dirt collection chamber  11 , or independently from any other chamber. 
     Outwardly Biased Suction Hose 
     The following is a description of an outwardly biased suction hose and a suction hose chamber therefor, which may be used by itself or in any surface cleaning apparatus or in any combination or sub-combination with any other feature or features disclosed herein. 
     Referring to  FIG. 1 , when a user is grasping the handle  17  to drive and maneuver the surface cleaning head  3 , the chassis portion  2  may be pulled along via hose  7 . Typically, a hose is extensible and is biased to a contracted position. If the portion of the hose  7  extending between the handle  17  and the chassis portion  2  is elastic or otherwise extensible it may be difficult for a user to accurately control the movement of the chassis portion  2 . For example, for a user to advance the chassis portion  2 , the hose  7  would have to be stretched to its maximum length before a suitable pulling force would be transmitted to the chassis portion  2 . 
     Alternatively, the hose may be configured as a compressible hose that is biased or sprung toward its extended configuration. The hose may include any type of suitable biasing member, such as a spring. The biasing member may be incorporated into the sidewall of the hose, or affixed to the interior or exterior surface of the hose. Accordingly, in its neutral state, the hose is extended and not contracted. 
     For storage and/or when the full length of the hose is not required for cleaning, the hose may be axially compressed into a retracted configuration (which may be at or close to its minimum length) within a suitable storage chamber, which may be part of a cord reel or part of a surface cleaning apparatus. The hose may be held in its compressed state within the storage chamber, which may help reduce the overall size of the surface cleaning apparatus. The hose may be held in place and compressed using any suitable securement mechanism. 
     When the surface cleaning apparatus is in use a desired length of hose may be metered out from the storage chamber by selectively releasing the securement mechanism and allowing the hose to spring or extend outward from the chamber due to its internal biasing member. When a desired length of hose is exposed, the user may re-engage the securement mechanism to contain the remainder of the hose within the storage chamber. 
     Preferably, the hose is not further extensible beyond its extended configuration. In this configuration, the exposed, uncompressed length of hose will not further stretch or extend when used to pull the chassis portion  2 . 
     Referring to  FIG. 15 , another embodiment of a surface cleaning apparatus  1001  is shown. The surface cleaning apparatus  1001  is generally similar to apparatus  1 , and analogous features are identified using like reference characters indexed by 1000. 
     In this embodiment, the hose  1007  is a compressible hose that can be compressed from an extended length to a compressed or retracted length. Referring also to  FIG. 16 , the hose  1007  includes a biasing spring  1200  within the hose sidewall  1201  that is configured to bias the hose  1007  toward its extended length. The hose wall  1201  is preferably not otherwise extensible so that the hose  1007  generally cannot be stretched beyond its extended length. Optionally, in addition to a biasing spring  1200 , the sidewall  1201  may also include one or more electrical conductors, e.g. wires  1203 , to transmit electrical power and/or control signals from the surface cleaning unit  4  to the handle  17 , and optionally downstream to the surface cleaning head  3  (for example to power a brush motor in the cleaning head  3 ). 
     In the illustrated embodiment, a hose storage chamber  1204  is provided as a portion of the up flow conduit  16 , adjacent the handle  1017 . The hose storage chamber is configured to contain the compressed portions of the suction hose  1007 , and preferably has a length  1205  that is between about 50% and about 100% or more of the length of the hose  1007  in its fully compressed state, so that the chamber  1204  is sized to contain substantially all of the hose  1007  when it is compressed. 
     Referring also to  FIG. 17 , a schematic representation of the hose storage chamber  1204  illustrates a compressed portion  1207  of the hose  1007  contained within the storage chamber  1204 , upstream from the securement mechanism  1208  which holds the hose  1007  in its compressed state. An uncompressed or extended portion  1209  of the hose  1007  is located outboard or downstream from the securement mechanism  1208  and, in the example illustrated, extends through the hollow interior  1210  of handle  1017 . 
     In the illustrated embodiment, the securement mechanism  1208  includes a pair of latch members  1211  that are pivotally mounted within the chamber  1204  at pivot joints  1212 . Each latch member  1211  includes an engagement end  1213  that frictionally engages the outer surface of the hose  1007  to prevent relative axial movement between the engagement ends  1213  and the hose  1007 . When the latches  1211  are in their engaged position ( FIG. 17 ), the uncompressed portion  1210  of the hose  1007  is maintained at a fixed length. 
     To allow additional hose  1007  to be drawn from the storage chamber  1204 , the latch members  1211  may be disengaged by a user. In the illustrated embodiment, each latch member  1211  includes a contact portion  1214  that can be engaged by the user. Squeezing or otherwise depressing the contact portions  1214  in the radial direction will cause the latch members  1211  to pivot about their respective pivot joints  1212  and will move the engagement ends  1213  out of contact with the outer surface of the hose  1007 . This will allow the compressed portion  1207  of the hose  1007  to expand under its own biasing force, and to expand until the latch members  1211  are re-engaged, or until the hose  1007  reaches maximum length. 
     Preferably, the latch members  1211  are biased toward their engaged positions, for example by springs  1215  so that the latch members  1211  hold the hose  1007  in place until triggered by the user. 
     Optionally, the open end of the storage chamber  1204  can include one or more guide members to help guide or direct the hose  1007  as it expands outwardly. This may help prevent kinks or other damage to the hose. In the illustrated embodiment, the storage chamber  1204  includes guide members in the form of rollers  1216  positioned toward the end of the chamber  1204 , and outside the latch members  1211 . The rollers  1216  may rollingly contact the hose  1007  as it expands and may help prevent the hose  1007  from being curved or bent too tightly or from otherwise becoming snagged to caught within the chamber  1204 . 
     Optionally, the rollers  1216  may be dampened or otherwise configured so that they provide a desired degree of rolling resistance when the hose  1007  is expanding. Providing resistance with the rollers  1216  may absorb some of the expansion force of the spring  1200 , and may help control the speed at which the hose  1007  expands from within the storage chamber  1204 . This may help prevent the hose  1007  from expanding more than desired or from otherwise overwhelming the user when the latches  1211  are disengaged. While illustrated as standalone rollers  1216 , the rollers  1216  may be connected to any suitable drive apparatus (such as an electric motor) to further control the expansion of the hose  1007 . 
     When a user is finished with a given cleaning task, it may be desirable to re-compress the hose  1007  into the storage chamber  1204 . In the illustrated embodiment, the latches  1211  are configured as one-way latches so that when the hose  1007  is pushed inwardly (for example by the user) the latches  1211  will automatically pivot or ratchet to allow the hose  1007  to move freely inwardly (without needing to depress the contact portions  1214 ), but will resist expansion of the hose  1007 . Alternatively, instead of manually inserting the hose  1007 , the hose storage chamber  1204  may include an automated hose compression system. For example, in the illustrated embodiment the rollers  1216  may be powered and may be operable to drive the hose  1007  into the storage chamber  1204 . Alternately, rollers  1216  may be electrically driven and used without latch members  1211  or the like. 
     Optionally, instead of being provided on the up flow duct, the hose storage chamber may be provided in the body of a surface cleaning apparatus, e.g., in a canister or base portion of the surface cleaning apparatus. Providing the hose storage chamber in the canister may position most of the weight of the hose within the canister (which rolls along the ground during normal use) and may therefore help reduce the amount of weight that is carried directly by the user holding the handle  17 . In the illustrated example such a hose storage chamber could be provided on the chassis portion  2  and/or the surface cleaning unit  4 . 
     Referring to  FIG. 18 , a schematic example of a canister style vacuum cleaner  2001  is shown. The surface cleaning apparatus  2001  is generally similar to the apparatus  1 , and analogous features are identified using like reference characters indexed by 2000. In this embodiment, the surface cleaning unit  2004  is integral with the chassis portion  2002  to form the canister portion, and the hose storage chamber  2204  is provided within the canister portion. 
     Referring to  FIG. 19 , a schematic representation of an alternate embodiment of a hose storage chamber  3204  is shown. The hose storage chamber  3204  is generally similar to hose storage chamber  1204 , and analogous features are identified using like reference characters indexed by 2000. In this embodiment, the securement mechanism  3208  includes rollers  3217  instead of latches. The rollers  3217  each include engagement projections  3218  for contacting and securing the hose  3007 . The rollers  3217  are preferably driven using any suitable driving mechanism (e.g. an electric motor and/or a spring that may be manually wound) and can be used to drive the hose  3007  into the storage chamber  3204  for storage. Optionally, the rollers  3217  need not be configured to drive the hose  3007  outward, and instead may simply be unlocked and allowed to rotate with the hose  3007  as it expands under its own biasing force. Preferably, the rollers  3217  can be locked in place in order to hold the hose  3007  in a fixed position. 
     Surface Cleaning Unit with Onboard Energy Storage Device 
     The following is a description of an portable surface cleaning unit with an on board energy storage member and alternate configurations of a base, which may be used by itself or in any surface cleaning apparatus or in any combination or sub-combination with any other feature or features disclosed herein. 
     Referring to  FIG. 1 , in the illustrated embodiment, the suction motor  8  is provided within the surface cleaning unit  8 . The electrical power cord  80  is, in this embodiment, connected to the surface cleaning unit  4  and remains connected when the surface cleaning unit  4  is separated from the chassis  2  ( FIG. 5 ) to supply power to the surface cleaning unit  4 . In a first alternate embodiment, power cord  80  may be connected to the chassis portion  2  instead of directly to the surface cleaning unit  4 . In this first alternate configuration, the surface cleaning unit  4  may be electrically coupled to the chassis portion  2  when mounted on chassis portion  2 . 
     According to this embodiment, surface cleaning unit  4  includes at least one on board power supply or power storage device, which may comprise, for example, one or more of a battery, fuel cell and external combustion engine. In such configurations, the surface cleaning module may be powered by AC power when docked, and powered by the on board power storage device when detached from the chassis portion. The suction motor may be configured to run on AC power when the surface cleaning unit  4  is mounted on the chassis. If the on board power supply provides DC power (such as a battery) the suction motor may also be operable to run on DC power when the surface cleaning unit is detached (for example, the suction motor may have dual windings). 
     Optionally, the chassis portion or the surface cleaning unit  4  may include an electrical system for converting AC power to DC power (including, for example, a rectifier, inverter, transformer and other suitable equipment) so that the suction motor in the surface cleaning unit may run on DC power when detached and when docked. This may allow a single motor configuration to be used. Alternatively, the suction motor may be selected so that it is directly compatible with AC and DC power sources, such that a converter on the chassis portion to feed DC power to the surface cleaning unit is not needed. 
     Preferably, the on board power storage device in the surface cleaning unit can be recharged, and more preferably can be recharged when the surface cleaning unit is docked on the chassis portion. Optionally, the chassis portion can be configured to charge the surface cleaning unit while the suction motor is running (while the apparatus is in use), and/or while the suction motor is off (the apparatus is in storage). 
     In a second alternate embodiment, a different power cord  80  may be connected to the chassis portion  2  in addition to the power cord connected to the cleaning unit  4 . In a third alternate embodiment, power cord  80  may be selectively connectable to the chassis portion  2  and the surface cleaning unit  4 . In this third alternate configuration, the surface cleaning unit  4  may be electrically coupled to the chassis portion  2  when mounted on chassis portion  2  and power cord  80  is connected to chassis  2  or power cord  80  may be directly connected to the surface cleaning unit  4  and directly power the surface cleaning unit  4 . 
     Referring to  FIG. 20 , another embodiment of a surface cleaning apparatus  4001  and surface cleaning unit  4004  are shown. The surface cleaning unit  4004  is shown with its upper cover cut-away and cyclone bin assembly removed. The surface cleaning unit  4001  is generally similar to surface cleaning unit  1 , and analogous features are illustrated using like reference characters indexed by 4000. 
     Referring to  FIG. 21 , in this embodiment, the electrical power cord  4080  is connected to the chassis portion  4002 , instead of the surface cleaning unit  4004 . To provide electrical communication, the chassis portion  4002  includes an electrical connector  4300  (preferably a female socket as exemplified) and the surface cleaning unit  4004  includes a mating electrical connector  4301  (e.g., male prongs in the illustrated example) that is mated with the connector  4300  when the surface cleaning unit  4004  is docked on the chassis portion  4002 . 
     To power the surface cleaning unit  4004  when it is detached, in this embodiment the surface cleaning unit  4004  includes an on board power storage device in the form of batteries  4302  ( FIG. 20 ), which are electrically connected to suction motor  4008 . When the surface cleaning unit  4004  is detached from its chassis portion  4002  the suction motor  4008  is powered by the batteries  4302 . 
     In the illustrated example, the suction motor  4008  is a DC motor, and the surface cleaning unit includes an on board converter module  4303  for converting AC power from the cord  4080  into DC power suitable for the motor  4008 . Preferably, the batteries  4302  can be rechargeable batteries, and when the surface cleaning unit  4004  is docked, AC power from the wall may be used to charge the batteries  4302 . The converter module  4303  is also configured to allow the batteries  4302  to be charged when the surface cleaning unit  4004  is connected to AC power. The converter module  4303  may include any suitable combination of components, including, for example, an inverter, a transformer and a rectifier. 
     Alternate Power Modes 
     The following is a description of a portable surface cleaning unit with alternate power modes, which may be used by itself or in any surface cleaning apparatus or in any combination or sub-combination with any other feature or features disclosed herein. 
     Referring to  FIG. 22 , a schematic representation of the surface cleaning apparatus  4001  is shown. Optionally, a controller  4450  can be provided to alter the operation of the suction motor  4008  based on its power supply. For example, when the controller senses that the surface cleaning unit  4008  is being powered by an external power supply (e.g., AC power via cord  4080 ) the suction motor  4008  can be operated at a relatively high power or “full power” mode. Alternatively, when the surface cleaning unit  4004  is being powered by the on board power storage member (e.g. batteries and is being run on DC current), the controller may operate the motor  4008  at a relatively lower power level. Operating at a lower power level may help prolong the amount of cleaning time that can be obtained using the on board batteries. 
       FIGS. 23 and 24  illustrate example embodiments of a converter module  4303 . Generally, converter module  4303  operates to convert AC signals to DC signals. The converter module  4303  may also transform an input power signal to a signal suitable for the operation of the surface cleaning apparatus  4001 . It will be understood that converter module  4303  may be provided in one or more different configurations. 
     In  FIG. 23 , converter module  4303 A includes an input terminal  4309 , a rectifier block  4310 , a transformer block  4311  and output terminals  4312 ,  4313 . The input terminal  4309  receives an input AC signal  4314  from the mating electrical connector  4301  and provides the input AC signal  4314  to the rectifier block  4310  and the transformer block  4311 . The rectifier block  4310  may include one or more electrical components for converting the input AC signal  4314  to a rectified signal  4315 . For example, the rectifier block  4310  can include one or more diodes in various configurations as known in the art. The rectifier block  4310  provides the rectified signal  4315  to the transformer block  4311 . 
     In some embodiments, the rectifier block  4310  can also include a filter or a regulator for stabilizing a version of the rectified signal  4315  prior to generating and providing the rectified signal  4315  to the transformer block  4311 . 
     The transformer block  4311  may include one or more electrical components for varying the rectified signal  4315  to a signal suitable for the operation of the surface cleaning apparatus  4001 . For example, the input power signal  4314  received at the input terminal  4309  may be from the wall outlet and therefore, the value of the input power signal  4314  may need to be lowered. As illustrated in  FIG. 23 , the transformer block  4311  is coupled to the two output terminals  4312 ,  4313 . The transformer block  4311  generates an output DC signal  4317  and an output AC signal  4318 , and then provides the output DC signal  4317  to the output terminal  4312  and the output AC signal  4318  to the output terminal  4313 . 
     As described above, the motor  4008  may be a motor that operates on AC power or DC power. When the motor  4008  operates on AC power, the motor  4008  can receive power via the output terminal  4313 . Alternatively, when the motor  4008  operates on DC power, the motor  4008  can receive power via the output terminal  4312 . The batteries  4302  may also be charged via the output terminal  4312 . For example, the batteries  4302  may be charged via the output terminal  4312  while the surface cleaning apparatus  4001  is docked on the surface cleaning unit  4 . The batteries  4302  may be charged while the surface cleaning apparatus  4001  is in use or when the surface cleaning apparatus  4001  is not in use. 
     In some embodiments, the converter module  4303  can include only one output terminal, such as the output terminal  4312 . Transformer block  4311  can therefore generate and provide only one output signal, such as the output DC signal  4317 , to the output terminal  4312 . 
       FIG. 24  illustrates a converter module  4303 B. The transformer block  4311  may be provided as two separate transformer blocks  4311 A,  4311 B. Similar to the transformer block  4311  of  FIG. 24 , the transformer block  4311 A receives the rectified signal  4315  from the rectifier block  4310 . However, unlike the transformer block  4311  of  FIG. 24 , the transformer block  4311 A generates only the output DC signal  4317 , which is then provided to the output terminal  4312 . The transformer block  4311 B receives the input AC signal  4314  from the input terminal  4309  in order to generate the output AC signal  4318 . 
     It will be understood that the rectifier block  4310  and the transformer block  4311  may be provided in a different order than as illustrated in converter modules  4303 A,  4303 B. For example, the transformer block  4311  may receive the input AC signal  4314  to generate a transformed signal which is either provided to the rectifier block  4310  for processing and/or directly to the output terminal  4313 . 
     Electrical Cord Reel 
     The following is a description of an electrical cord reel, which may be used by itself or in any surface cleaning apparatus or in any combination or sub-combination with any other feature or features disclosed herein. 
     When the surface cleaning apparatus is not in use, it may be desirable to wind the electrical cord for storage. Optionally, a cord reel can be provided to wind and hold the cord  80 . The cord reel may be of any suitable configuration and may be a manually actuated reel (for example via a hand crank) or an automated reel. If the reel is automated (i.e. can wind the cord without manual user intervention), it may be driven by any suitable mechanism including, for example, a spring, a biasing mechanism and/or a motor. The motor used may be an electric motor that can be operated at a speed that is suitable for winding the cord. If the motor is electric, preferably the cord reel is provided with a power source (either on board or as part of the surface cleaning apparatus) so that the cord reel motor can be powered even after the electrical cord has been unplugged. 
     Optionally, the cord reel, and associated power sources, controllers, switches, etc. can be internal (i.e. inside one portion of the surface cleaning apparatus) or external to the surface cleaning apparatus. For example, referring to  FIG. 25 , if the electrical cord  80  is connected to the surface cleaning unit  4 , any suitable cord reel (illustrated schematically as box  400 ) may be provided inside the surface cleaning unit  4 . Alternatively, referring to  FIG. 26 a   , if the electrical cord  4080  is attached to the chassis portion  4002 , a cord reel  4400  can be provided in the chassis portion  4002 . 
     In one embodiment, cord reel  4400 , may be configured to automatically wind or unwind the cord based on at least one operating condition of the surface cleaning apparatus. For example, the surface cleaning apparatus may include a controller  4450  that is capable of sensing or detecting an operating condition of the surface cleaning apparatus  4001  and then control the cord reel based on the operating condition. Such a cord reel may optionally, but need not, include any of the other features of a cord reel disclosed herein 
     For example, referring to  FIG. 26 b   , a schematic representation of a cord reel  4400  and a control system therefor is illustrated. While a schematic is illustrated, the control system may be of any suitable configuration. In the illustrated embodiment, the control system includes the controller  4450  (e.g. a PLC, microprocessor or onboard computer) that is communicably linked to the cord reel module  4400 . In this configuration, the cord reel  4400  includes a motor  4424  to drive the reel  4401  and an on board power supply in the form of batteries  4423  to power the motor  4424 . The controller  4450  is connected to control the operation of the motor  4424 . 
     One or more suitable sensors can be provided on the surface cleaning apparatus and connected to the controller  4450 . In the illustrated example, the control system includes a position sensor  4451  connected to the controller. The position sensor  4451  can be any suitable type of sensor that can detect the rate and direction of movement of the chassis portion  4002 . For example, the sensor  4451  can be an encoder that can measure the speed and direction of rotation of the wheels  100 , or may be an optical sensor that can determine movement by visually tracking the surface under the chassis portion  2  or the rotation of a wheel of the chassis, or any other suitable sensor. In one embodiment, the controller can be configured to determine when the vacuum cleaner is moving forward and to unwind cord  80  from the reel  4401  at a given rate based on the speed of the movement. Alternately or in addition, the controller may be configured to wind cord  80  onto the reel  4401  when the chassis portion  4002  is moved backward. Alternatively, the sensor  4451  may be a receiver (e.g. a radio receiver) configured to receive external data, for example from a transmitter positioned adjacent the wall. Using this signal, the controller may be able to determine the position of the chassis portion  4002  relative to the transmitter and to unwind cord as the chassis portion  4002  moves farther from the transmitter and to wind the cord  80  as the chassis portion  4002  moves closer to the transmitter. Such a system may also be used in combination with a cord reel  400  that is provided in the carryable surface cleaning unit  4 , which may not have wheels or be in visual proximity to the ground. 
     An analogous control system, and or controller, may be included in other portions of the surface cleaning apparatus, including, for example, in the surface cleaning unit  4  or  4004 , and optionally in the body or control/drive module of an external cord reel. 
     In another embodiment, the cord reel may be a separate unit (i.e., it may not be incorporated into the surface cleaning unit  4  or chassis) and may have an on board energy storage member (e.g., one or more batteries). Preferably, the batteries are charged when the cord reel is plugged into the wall. The cord reel may have a first short cord that is configured to plug into a household electrical outlet and a second longer cord that is configured to be plugged into the surface cleaning apparatus. Such a cord reel may optionally, but need not, include any of the other features of a cord reel disclosed herein. 
     For example, referring to  FIG. 26 c   , the cord reel  4400  may be separable from the chassis portion  4002  and may be configured as an external cord reel. In this configuration, the cord reel  4400  may be separated from the chassis portion  4002  and rested on the ground, for example adjacent a power socket. The cord  4080  can then be unwound from the reel  4400  as required to allow the chassis portion  4002  to be moved away from the wall socket. This may reduce the weight of the chassis portion  4002 . In this embodiment, the controller  4450  may be located within the external cord reel, instead of within the surface cleaning unit  4004  or chassis portion  4002 . Optionally, the sensor  4451  can be a radio receiver and the chassis portion  4002  can include a corresponding transmitter  4452  to allow the controller  4450  to determine the distance of the chassis portion  4002  from the cord reel  4400 , and to unwind and/or wind cord  80  as required. 
     Referring to  FIG. 26 d   , an analogous system can be used if an external cord reel module  400  is connected to the surface cleaning unit  400 , instead of the chassis portion  2 . 
     In the illustrated example, the cord reel  400  may be a spring-powered cord reel that can wind the cord using potential energy stored in a spring. To activate the cord reel, a user can press the cord reel button  81  on the surface cleaning unit  4  to retract the cord  80 . Alternatively, if the cord reel  400  were electrically driven, batteries could be provided within the surface cleaning unit  4  (for example, similar to the batteries  4302 ) to power the cord reel. 
     In another embodiment, the cord reel may be configured as a dual-wind cord reel, in which the reel is positioned between the ends of the cord and winds the cord in two directions simultaneously (e.g. one revolution of the reel winds two lengths of cord). Such a cord reel may optionally, but need not, include any of the other features of a cord reel disclosed herein 
     Optionally, the dual-wind cord reel may be configured so that it connects to the cord without interrupting or forming part of the electrical connection between the ends of the cord. In this configuration, the cord reel need not include any type of rotatable or pivotal electrical connections, or any electrical connections at all, and may be referred to as a sealed or brushless cord reed. In this configuration, the integrity of the electrical insulation of the cord remains intact, which may be desirable if used in wet or other hazardous locations. 
     Referring to  FIG. 27 , an embodiment of a cord reel  401  that is suitable for use with surface cleaning apparatus  1 ,  4001  and/or other surface cleaning apparatuses is shown. The cord reel  401  includes a body  402  that rotatably supports a reel member  403 . The reel includes an inner sidewall  403  that is rotatable about a reel axis  404 . A central spindle member  405  projects axially from the reel member  403  and rotates with the inner sidewall  403 . A handle  406  is provided toward the top of the body  402  to allow a user to grasp and/or carry the cord reel  401  when it is separated from the surface cleaning apparatus. 
     In the illustrated embodiment, the cord reel  401  is configured to be attached to a portion of the cord  80  that is intermediate its two ends and preferably proximate the center of the power cord and, more preferably, the reel  401  is connected to the middle of the cord  80 . Connecting to the middle of the cord  80  may help ensure that the cord  80  winds generally evenly around the spindle  405 . Optionally, to help retain the cord on the spindle  405  the reel  401  can include an outer sidewall  407  that is connected to the free end  408  of the spindle  405 . In the illustrated embodiment the outer sidewall  407  is detachable from the spindle  405 . This may allow the cord  80  to be connected to the cord reel  401  and may help facilitate removal of the wound cord from the reel. 
     For example, in the illustrated embodiment, to attach the cord reel  401  to the cord  80 , the cord  80  is axially inserted into a slot  410  on the spindle  405 . The slot  410  can be sized to receive a given cord  80 , and may extend along some, or substantially all of the length of the spindle  405 . Extending the slot  410  the entire length  411  of the spindle  405  may allow the cord  80  to be positioned at any location along the spindle length. Inserting the cord  80  axially into the slot  410  eliminates the need to feed either end of the cord  80  through the slot  410  (or other portions of the reel  401 ), which may allow for the slot  410  to be sized to have a width  412  that is generally equal to the width  413  of the cord  80 . 
     Optionally, to help position the cord reel  401  in the middle of the length of the cord  80 , the cord  80  may be provided with a locating member identify the middle of the cord. Preferably, the locating member is compatible with the cord reel  401  and more preferably, can fit within or otherwise engage the spindle  405  (or other suitable portion of the cord reel  401 ). 
     Referring to  FIG. 27 a   , one example of a locating member is stripe  413  provided on cord  80 . The stripe  413  is visual indication of the middle of the cord  80 , and a user may align the cord reel  410  with the cord  80  by inserting the striped portion  413  into the slot  405 . Optionally, the stripe  413  may be integral with the cord  80  (e.g. formed as a differently colored portion of the cord  80  insulation, etc.) or may be painted or otherwise marked on the outer surface of the cord  80 . While a stripe is illustrated, the visual indicator may be any suitable feature, including, for example, a sticker or wrapper, lettering or other words, a change in texture of the cord  80  surface, etc. 
     Optionally, instead of a visual indicator, the locating member may be a physical object that is configured to engage or mate with the spindle  405 . For example, referring to  FIGS. 28 a - c   , instead of (or in addition to) a visual stripe  413 , a locating member may be provided as an anchor member  413   a . In the illustrated example the anchor member  413   a  is a generally triangular member that is attached to the cord  80 . The anchor member  413   a  includes two mating halves  416  and  417  each of which includes a cord channel  418  extending therethrough. The halves  416 ,  417  can be fastened together using any suitable mechanism, including fasteners inserted into apertures  419 , a snap fit or press fit and other connecting clamps or clips. Optionally, the anchor member  413   a  can be provided separately from the cord  80 . This may allow a user to attach the anchor member  413   a  to any cord the user wishes to use in combination with the cord reel  401 . 
     In the illustrated embodiment, in addition to the cord slot  410 , the spindle  405  includes a central bore  418  that is configured to slidingly receive the anchor member  413   a . To accommodate the triangular anchor member  413   a , the bore  418  has three sides  119   a - c . In other configurations, both the anchor member  413   a  and bore  418  may have a different, corresponding shape, including, for example, square, pentagon, hexagon, etc. Referring to  FIG. 33 , the anchor member  413   a  is shown inserted into bore  418 . In this configuration, the anchor member  413   a  can also act as an alignment or keying member as it is configured to fit into the bore  418  in an orientation such that the cord  80  also passes through slots  410 . 
     In some configurations, when the spindle  405  is rotated faces  119   a - c  may engage and exert forces on corresponding faces on the anchor member  413   a . This may help reduce the amount of force exerted directly on the cord  80  by the reel  401 , which may help reduce cord damage. 
     Referring to  FIG. 27 b   , when the locating member (of any suitable configuration) is nested within the spindle  405 , the outer sidewall  407  can be attached (for example snapped in place or attached using clips or other suitable means) to secure the cord  80  on the reel  401 . The spindle  405  and sidewalls  403  and  407  can then be rotated using any suitable means to wind the cord  80  onto the reel  401 . In the illustrated embodiment, both sides of the cord are drawn inwardly toward the reel  401  and wrapped around the spindle  405 . 
     Referring to  FIG. 27 c   , when the cord  80  is fully wound on the reel  401 , both ends of the cord  80 , female socket  414  and male prongs  415 , can be pulled within the perimeter of the cord reel  401 . In this embodiment, the prongs  415  are configured to connect to a standard wall socket, and the socket  414  is configured to detachably connect to a corresponding port/coupling on the surface cleaning apparatus. Alternatively, the female end of the cord  80  may be fixedly connected to the surface cleaning apparatus, and need not be detachable. 
     Referring to  FIG. 27 d   , to remove the cord  80  from the reel  401 , the user may unwind the reel or alternatively may remove outer sidewall  407  and then axially slide the coiled cord  80  off of the spindle  405 . This may allow a user to quickly remove the entire cord  80  from the reel  401  without having to unwind its entire length. 
     The cord reel  401  may be driven (i.e. wound and/or unwound) using any suitable mechanism, including for example a manual crank and a powered motor. Optionally, the reel  401  may include more than one driving mechanism, which may allow the reel to be operated under a variety of conditions. 
     Referring to  FIG. 27 b   , in the illustrated embodiment the cord reel  401  includes a drive module  420  provided at the lower end of the body  402 . In this configuration, the drive module  420  is generally opposite the handle  406  and is positioned below the spindle  405 . Preferably, the bottom surface  421  of the drive module  420  cooperates with the lower surface  422  of the rest of the body  402  to provide a base for the cord reel  401 . More preferably, the base is configured to support the cord reel in a generally upright position if/when it is placed on a flat surface (such as the ground). This may allow the cord reel  401  to remain upright when detached from the surface cleaning apparatus and positioned on the ground. 
     The drive module  420  preferably includes an onboard energy storage member in the form of batteries  423  and an electric drive motor  424 . The drive motor  424  can be connected to the spindle  405  in any suitable manner in order to drivingly rotate the spindle  405 . In the illustrated embodiment, the perimeter of the inner sidewall  403  is provided with a plurality of gear teeth  425  which extend into the drive module  420 . Inside the drive module  420 , the motor  424  is connected to a driving pinion or gear with teeth that mesh with the teeth on the sidewall  425 . 
     A switch  425  is wired between the batteries  423  and the motor  424  to control the operation of the motor  424 , and the subsequent rotation of the spindle  405 . The switch  425  may be any suitable type of switch, and in the example illustrated is a three-position switch. In this configuration, the switch can be moved into a “wind” position in which it causes the motor  424  and spindle  405  to rotate in one direction, an “unwind position” in which it causes the motor  424  and spindle  405  to rotate in the opposite direction, and an off position in which the motor  424  does not rotate. This may allow for powered winding and unwinding of the cord. Alternatively, or in addition, the drive mechanism may include a clutch or other suitable device so that in addition to being unwound using motor  424 , the cord may be unwound simply by pulling on one or both of its ends, and the spindle  405  is allowed to rotate in response to such tension on the cord  80 . 
     In addition to winding and unwinding, the motor  424  may be equipped with a torque sensor (e.g. current monitoring sensor) or other type of controller that can disengage or deactivate the motor  424  if the tension on the cord  80  exceeds a predetermined threshold (e.g. if the cord  80  is stuck or the  401  reel is jammed). This may help prevent damage to the motor  424 , the cord  80  and the reel  401 . 
     Preferably, if batteries are provided on board the cord reel, they are preferably rechargeable. The batteries may be charged if the cord reel  401  is connected to the body of the surface cleaning apparatus which has an on board energy storage member, and/or by placing the drive module  420  on an independent charging station or by connecting it to an external power source (e.g. a wall socket). Optionally, referring to  FIG. 29 , the drive module  420  may be removable from the body  402 . Removing the drive module  420  may help reduce the overall size and weight of the cord reel  401 . It may also allow the drive module  420  (if it includes the batteries) to be charged separately from the cord reel  401 , and/or to be serviced or replaced with a different drive module  420 . 
     Referring to  FIG. 30 , as an alternative to the electric drive module  420  or as a supplement thereto, the cord reel  401  may also include a manual drive mechanism to wind the cord  80 . This may be useful if the drive module  420  is removed and/or if the batteries  423  are dead. In the illustrated embodiment, the manual drive mechanism is provided in the form of a hand crank  425 . The hand crank  425  includes a hand grip portion  426  and a linkage arm  427 . The outer end  428  of the linkage arm is connected to the hand grip  426  and the inner end  429  is connected to the inner sidewall  403  and spindle  405 . Rotating the hand crank  425  winds and unwinds the cord  80 . When not in use, the hand grip portion  426  can be moved from a deployed position ( FIG. 30 ) to a retracted position ( FIG. 31 ), which may help reduce the overall size of the cord reel  401 . Reducing the size of the cord reel  401  may help facilitate storing and/or mounting the cord reel  401  on a surface cleaning apparatus. 
     As exemplified in  FIG. 32 , the cord reel  401  may be configured to be mounted to, and carried on, the surface cleaning apparatus  1 . To accommodate the external cord reel  401 , the surface cleaning unit  4  may include a reel mount  430  and the cord reel  401  may include a complimentary mounting flange  431  provided on the back of the body  402  ( FIG. 30 ). The mounting flange  431  may be configured to fit within the cord mount  430  and can be held in place by gravity, and/or the use of any suitable securing or locking members, including, latches, magnets, pins, detents, clips and other fasteners. 
     Preferably, in addition to providing a physical connection, the cord mount  430  and flange  431  can also include reciprocal electrical connectors (e.g. a mating socket and prongs). In this configuration, when the cord reel  401  is docked on the surface cleaning unit  4 , and the surface cleaning unit  4  is powered (either by an external source or an on board source) the cord reel  401  can receive power from the surface cleaning unit  4 , or vice versa. This may allow the batteries  423  to be charged when the cord reel  401  is mounted on the surface cleaning apparatus  1 . Alternately, the reciprocal electrical connectors may be used to power the surface cleaning unit when the power cord is plugged into an electrical outlet. 
     Optionally, the cord reel  401  may carry the only cord  80  provided with the surface cleaning apparatus  1 . In such a configuration, one end of the cord  80  is connectable to a port or connector on the surface cleaning apparatus  1 . Alternatively, the cord reel  401  may carry an additional or supplemental cord  80 , and the surface cleaning apparatus  1  may include at least one internal cord reel as well. In such a configuration, the cord  80  on the cord reel  401  may function as an extension cord, and one end of the cord may be connected to the wall socket while the other end of the cord is coupled to the free end of the electrical cord that is integral the surface cleaning apparatus. 
     In the illustrated embodiment, mounting the cord reel  401  onto the back side of the surface cleaning unit  4  could potentially interfere with the air flow exiting the clean air outlet  6 . To help facilitate air flow, the inner sidewall  403  and outer sidewall  407  are provided with a plurality of air flow apertures  432  to allow air to flow through the cord reel  401 . 
     In an alternate embodiment, the cord reel could produce a DC output, such as by having an on board power supply. 
     Any of the features of the cord reels disclosed herein may be used with any other type of surface cleaning apparatus. The following description exemplifies a number of the features of a cord reel disclosed herein in an upright-style surface cleaning apparatus. Referring to  FIG. 34 , another embodiment of an upright-style surface cleaning apparatus  5001  is shown. Surface cleaning apparatus  5001  is generally similar to surface cleaning apparatus  1 , and analogous features are identified using like reference characters indexed by 5000. 
     In this embodiment, the chassis portion  5002  is configured as the upper portion of the surface cleaning apparatus, and includes the rigid up flow duct  5016 . In  FIG. 34 , the surface cleaning unit  5004  is illustrated including an optional internal cord reel  5400  that may include any of the features of the cord reels described herein. Referring to  FIG. 35 , the surface cleaning apparatus  5001  is illustrated with an external cord reel  5400  that includes a motor  5424 , batteries  5423 , controller  5450 , sensor  5451  and transmitter  5452  as described herein. Optionally, some or all of these features may also be provided in the internal cord reel  5400  in  FIG. 34 . Preferably, the surface cleaning unit  5004  is detachable from the chassis portion  5002 , which may allow the user to reconfigure the surface cleaning apparatus  5001  into a variety floor and above-floor cleaning modes. 
     Hand Carriable Surface Cleaning Apparatus 
     The following description exemplifies a number of the features disclosed herein in a hand carriable surface cleaning apparatus (e.g., a hand vacuum cleaner, a pod vacuum cleaner or any other surface cleaning apparatus that may be carried by a handle or a shoulder strap or the like). Referring to  FIG. 37 , another embodiment of a hand carriable surface cleaning apparatus  10900  is shown. 
     The surface cleaning apparatus  10900  includes a main body  10901  having a handle  10902 , a dirty air inlet  10903 , a clean air outlet  10904  (see for example  FIG. 26 ) and an air flow path extending therebetween. In the embodiment shown, the dirty air inlet  10903  is the inlet end of connector  10906 . Optionally, the inlet end  10905  can be used to directly clean a surface. Alternatively, the inlet end can be connected to the downstream end of any suitable cleaning tool or accessory, including, for example a wand, a nozzle and a flexible suction hose. 
     The connector  10906  may be any suitable connector that is operable to connect to, and preferably detachably connect to, a cleaning tool or other accessory. Optionally, in addition to provide an air flow connection, the connector may also include an electrical connection  10909  ( FIG. 38 ). Providing an electrical connection  10909  may allow cleaning tools and accessories that are coupled to the connector  10906  to be powered by the surface cleaning apparatus  10900 . For example, the surface cleaning unit  10900  can be used to provide both power and suction to a surface cleaning head, or other suitable tool. In the illustrated embodiment, the connector  10909  includes an electrical coupling in the form of a female socket member, and a corresponding male prong member may be provided on the cleaning tools and/or accessories. Providing the female socket on the electrified side of the electrical coupling may help prevent a user from inadvertently contacting the electrical contacts. 
     Referring to  FIG. 39 , a construction technique that may be used by itself or with any other feature disclosed herein is exemplified. In this embodiment, the main body portion  10901  of the surface cleaning apparatus includes a core cleaning unit  11000  and an outer shell  11001 . In the illustrated example, the core cleaning unit  11000  is a generally, self-contained functional unit that includes the dirty air inlet  10903 , air treatment member  10910 , pre-motor filter chamber  10956 , suction motor  10911  and clean air outlet  10904 . The outer shell includes mating side panels  11002 , the handle portion  11003  of the surface cleaning apparatus (including the primary power switch  10985 ) and an openable pre-motor filter chamber cover  10959 . When the outer shell  11001  is assembled around the core cleaning unit  11000  the exposed outer surfaces of the surface cleaning apparatus  10900  are formed from a combination of portions of the core cleaning unit  11000  and the outer shell  11001 . For example, the external suction motor housing  10912  and handle  10902  are provided by the outer shell  11001 , whereas the shell is shaped so that portions of the cyclone bin assembly  10910  sidewalls remain visible in the assembled configuration. If these portions are at least partially transparent, they can allow a user to see into the dirt collection chamber  10914  to determine if the dirt collection chamber  10914  is getting full. 
     From the dirty air inlet  10903 , the air flow path extends through the cyclone bin assembly  10910  which forms part of the main body of the surface cleaning apparatus. A suction motor  10911  (see  FIG. 44 ) is mounted within a motor housing frame  11004  ( FIG. 39 ) of the core cleaning unit  11000  and is in fluid communication with the cyclone bin assembly  10910 . In this configuration, the suction motor  10911  is downstream from the cyclone bin assembly  10910  and the clean air outlet  10904  is downstream from the suction motor  10911 . 
     Referring to  FIGS. 41 and 44 , a uniflow cyclone and/or a cyclone with rounded junctures, and/or a cyclone with an insert member any of which may be used by itself or with any other feature disclosed herein is exemplified. In the illustrated embodiment, the cyclone bin assembly  10910  includes a cyclone chamber  10913  and a dirt collection chamber  10914 . The dirt collection chamber  10914  comprises a sidewall  10915 , a first end wall  10916  and an opposing second end wall  10917 . The dirt collection chamber  10914  may be emptyable by any means known in the art and is preferably openable concurrently with the cyclone chamber  10913 . Preferably, the second dirt collection chamber end wall  10917  is pivotally connected to the dirt collection chamber sidewall by hinge  10919 . The second dirt collection chamber end wall  10917  functions as an openable door to empty the dirt collection chamber  10914  and can be opened ( FIGS. 42 and 43 ) to empty dirt and debris from the interior of the dirt collection chamber  10914 . The second dirt collection chamber end wall  10917  can be retained in the closed position by any means known in the art, such as by a releasable latch  10919   a . In the illustrated example, the hinge  10919  is provided on a back edge of the end wall  10917  and the latch  10919   a  is provided at the front of the end wall  10917  so that the door swings backwardly when opened. Alternatively, the hinge  10919  and latch  10919   a  may be in different positions, and the door  10917  may open in a different direction or manner. Optionally, instead of being openable, the end wall  10917  may be removable. 
     In the embodiment shown, the cyclone chamber  10913  extends along a cyclone axis  10920  and is bounded by a sidewall  10921 . The cyclone chamber  10913  includes an air inlet  10922  and an air outlet  10923  that is in fluid connection downstream from the air inlet  10922  and one dirt outlet  10924  in communication with the dirt collection chamber  10914 . In this embodiment, the dirt collection chamber  10914  is positioned adjacent the cyclone chamber  10913  and at least partially surrounds the cyclone chamber  10913  in a side-by-side configuration. 
     Preferably, the air inlet  10922  is generally tangentially oriented relative to the sidewall  10921 , so that air entering the cyclone chamber will tend to swirl and circulate within the cyclone chamber  10913 , thereby dis-entraining dirt and debris from the air flow, before leaving the chamber via the air outlet  10923 . The air inlet  10922  extends along an inlet axis  10925  that is generally perpendicular to the cyclone axis  10920 , and in the illustrated example is generally parallel to and offset above the suction motor axis  10926 . 
     In the illustrated example, the cyclone air outlet  10923  includes a vortex finder  10927 . Optionally, a screen  10928  can be positioned over the vortex finder  10927  to help filter lint, fluff and other fine debris. Preferably, the screen  10928  can be removable. 
     The air inlet  10922  has an inlet diameter  10934 , and a related inlet flow cross-sectional area (measure in a plane perpendicular to the inlet axis). Preferably, the air outlet  10923  is sized so that the diameter  10932  of the air outlet  10923 , and therefore the corresponding flow area of the air outlet  10923 , is the same as the diameter of the air inlet. Alternatively, the air outlet diameter  10932  may be between about 50% and about 150%, and between about 85-115% of the air inlet diameter  10925 . 
     In the example illustrated the cyclone bin assembly  10910 , and the cyclone chamber  10913  are arranged in a generally vertical, uniflow cyclone configuration. In a uniflow cyclone, the air inlet is located toward one end of the cyclone chamber and the air outlet is provided toward the other end of the cyclone chamber. In this configuration, air enters one end of the cyclone chamber and generally exits via the other end of the cyclone chamber, as opposed to the cyclone chamber illustrated in the embodiment of  FIGS. 1 to 18 , in which air enters and exits the cyclone chamber via the same end. In the illustrated example, the air inlet  10922  is provided toward the lower end of the cyclone chamber  10913  and the air outlet  10923  is provided toward the upper end of the cyclone chamber  10913 , such that air flows into the bottom of the cyclone chamber  10913  and exits at the top of the cyclone chamber  10913 . Alternatively, the locations of the air inlet and outlet can be reversed. 
     Optionally, instead of a vertical configuration, the cyclone bin assembly  10910  and cyclone chamber  10913  can be provided in another orientation, including, for example, as a horizontal cyclone. 
     Optionally, some or all of the cyclone sidewall  10921  can coincide with portions of the external sidewalls of the cyclone bin assembly  10910  and the dirt collection chamber sidewall  10915 . Referring to  FIG. 51 , in the illustrated embodiment the front portion of the cyclone chamber sidewall  10921  is coincident with the outer sidewall of the cyclone bin assembly  10910 , and the rear portion of the cyclone sidewall  10921  helps separate the cyclone chamber  10913  from the dirt collection chamber  10914 . This may help reduce the overall size of the cyclone bin assembly  10910 . Alternative, the sidewall  10921  may be distinct from the sidewalls  10915 . In alternative embodiments, the cyclone chamber  10913  may include only two dirt outlets  10924 , or more than two dirt outlets. 
     In the illustrated embodiment, the cyclone chamber  10913  includes a first or upper end wall  10937  ( FIG. 51 ) and a second or lower end wall  10943 . The upper end wall  10937  is connected to the upper end of the sidewall  10921 . In the illustrated example, a juncture  10938  between the end wall  10937  and the side wall  10921  is a relatively sharp corner that does not include any type of angled or radiused surface. In contrast, the lower end wall  10943  meets the lower end of the cyclone sidewall  10921  at a juncture  11005  that includes a curved juncture surface  11006  (see also  FIG. 45 ). The radius  11007  of the curved surface  11006  may be selected based on the radius of the air inlet (e.g. half of the diameter  10934 ), and optionally may be the selected so that the juncture surface  11006  has the same radius as the air inlet  10922 . 
     The curved juncture surface can be provided as a portion of the sidewall or as a portion of the end wall. In the illustrated embodiment, the curved juncture surface  11006  is provided as part of an insert member  11008  that is provided on the bottom end wall and extends upward into the interior of the cyclone chamber  10913 . The insert member also includes an upwardly extending projection member  11009  that extends into the interior of the cyclone chamber and engages the distal end  10930  of the screen ( FIG. 51 ). Together, the vortex finder  10927 , screen  10928  and projection member  11009  form a generally continuous internal column member that extends between the first and second end walls  10937  and  10943  of the cyclone chamber  10910 . Providing the projection member  11009  may help direct air flow within the cyclone chamber, and may help support and/or stabilize the distal end  10930  of the screen  10928 . 
     Optionally, the juncture  11010  between the end wall  10943  and the projection member  11009  may include a curved surface  11011  (see  FIGS. 41 and 44 ), and preferably is sized so that the surface  11011  has a radius  11012  that is the same as radius  11007 . Providing curved surfaces  11006  and  11011  at the junctures between the end wall  10943  and the sidewall  10921 , may help reduce backpressure and may help improve cyclone efficiency. Preferably, the two curved juncture surfaces  11006  and  11011  are separated by a generally flat, planar transition surface  11013 , having a width  11014 . Providing a flat transition surface  11013  may help improve air flow, and/or reduce back pressure to help improve cyclone efficiency. 
     In the illustrated embodiment, the second end wall  10943  of the cyclone chamber  10913 , and the insert member  11008  provided thereon, is integral with the openable bottom door  10917  that provides the bottom wall of the dirt collection chamber  10914 . In this configuration, opening the door simultaneously opens the cyclone chamber  10913  and the dirt collection chamber  10914  (see for example  FIGS. 42 and 43 ) for emptying. 
     In the illustrated embodiment, the dirt outlet  10924  is in the form of a slot having bottom and side edges provided by the cyclone chamber sidewall  10921 , and a top edge provided by the upper end wall  10937 . Alternatively, all four edges of the slot  10924  may be provided by the cyclone chamber sidewall  10921 . The dirt slot  10924  is positioned at the back of the cyclone chamber  10921  and is generally opposite the air inlet  10922 . In the illustrated embodiment, the upper wall  10937  of the cyclone chamber is integral with the upper wall  10916  ( FIGS. 41 and 44 ) of the dirt collection chamber  10914 . 
     Optionally, one or more pre-motor filters may be placed in the air flow path between the cyclone bin assembly  10910  and the suction motor  10911 . Alternatively, or in addition, one or more post-motor filters may be provided downstream from the suction motor. 
     Referring to  FIG. 45 , a filter housing construction that may be used by itself or with any other feature disclosed herein is exemplified. In the illustrated embodiment a pre-motor filter chamber or housing  10956  is provided between the upper walls  10937 ,  10916  of the cyclone  10913  and dirt collection chambers  10914  and the openable cover  10959 . In this configuration, the bottom wall  10957  of the pre-motor filter chamber  10956  is integral with the upper walls  10937 ,  10916  of the cyclone  10913  and dirt collection chambers  10914 , and the upper wall  10958   a  and sidewall  10958  of the pre-motor filter chamber  10956  are provided via a filter cartridge housing  11015  (see also  FIG. 46 ). The filter cartridge housing  11015  is separate from the openable cover  10959 . One or more filters may be positioned within the pre-motor filter chamber to filter fine particles from the air stream exiting the air outlet, before it flows into inlet of the suction motor. The filters may be of any suitable configuration and formed from any suitable materials. In the illustrated embodiment, a foam filter  10960  and a felt filter  10961  ( FIG. 30 ) are positioned within the pre-motor filter chamber  10956 . 
     Referring to  FIGS. 45-48 , the filter cartridge is a generally dome shaped member that includes an upper wall  10958   a  and a sidewall  10958  extending downwardly from the upper wall to surround the pre-motor filters  10960 ,  10961 . The pre-motor filters  10960 ,  10961  are shaped to fit within the cartridge member  11015 , and when inserted within the cartridge member ( FIG. 47 ) the downstream side  10965  of the felt filter  10961  forms the bottom surface of the filter cartridge  11015 . When the filter cartridge  11015  is inserted in its use position ( FIG. 46 ) the downstream side  10965  of the pre-motor filter rests on the support ribs  10962  (see  FIG. 47 ) on the bottom wall  10957 , and the downstream headspace  10964  ( FIG. 45 ) is defined between the downstream side  10965  of the filter  10961  and the bottom wall  10957 . 
     In this embodiment, the upstream headspace  10970  ( FIG. 35 ) is provided between the upstream side  10968  of the pre-motor filter  10960  and the upper wall  10958   a  of the cartridge housing  11015  (instead of being formed by the cover  10959 ). To provide air into the upstream headspace  1970 , the vortex finder  10927  projects upwardly from the bottom wall  10957  and the filters  10960  and  10961  are provided with a corresponding aperture  10972  to receive the vortex finder  10927 . Preferably, a plurality of spacing ribs  11016  ( FIG. 48 ) are provided on the inner surface of the upper wall  10958   a  to keep the upstream surface  10968  of the filter  10960  spaced apart from the inner surface of the upper wall  10958   a  to maintain the upstream headspace  10970 . 
     The lower rim  11017  of the filter cartridge  11015  housing is configured to seal against the bottom wall  10957  (for example via snap fit or by using any type of suitable gasket or sealing member) to provide a generally air tight pre-motor filter chamber  10956 . The sealed chamber  10956  is then covered by openable chamber cover  10959 . As the filter cartridge housing  11015  provides a sufficiently air tight connection to the bottom wall, the chamber cover  10959  need not be air tight. Preferably, at least a portion of both the chamber cover  10959  and the filter cartridge  11015  housing is transparent so that a user can inspect the upstream side  10968  of the pre-motor filter  10960  without having to remove it from the chamber  10956 . Optionally, both the chamber cover  10959  and filter cartridge housing  11015  may be formed from transparent plastic. 
     When a user wishes to remove, clean, change or otherwise access the pre-motor filter  10960 ,  10961  he/she may open the chamber cover  10959  ( FIG. 48 ) to expose the filter cartridge housing  11015 . The user may then detach the filter cartridge housing  11015  and separate it from the bottom wall  10957 . Preferably, the pre-motor filters  10960 ,  10961  are snugly received within the filter cartridge housing  11015  (or otherwise retained therein) so that the filters  10960 ,  10961  are removed with the filter cartridge housing  11015  and remain inside the filter cartridge housing  11015  until removed by a user. In this embodiment, the dirty, upstream side  10968  of the filter  10960  remains enclosed by the filter cartridge housing  11015  when separated from the core cleaning unit  11000 , and only the relatively clearer downstream side  10965  of the filter  10961  is exposed. This may help prevent dirt on the upstream side  10968  of the filter  10960  from spilling or from otherwise contacting the user. When at a desired location, for example at a trash receptacle or a sink, a user can grasp the clean, downstream side  10965  of the filter and remove it from the filter cartridge housing  11015 . The upstream side  10968  of the filter can then be cleaned and inspected as desired. 
     To assist a user, the upper side  1958   a  of the filter cartridge housing  11015  may be provided with a grip member, for example the flange  11018  in the illustrated embodiment ( FIG. 46 ), which may allow a user to firmly grasp and manipulate the filter cartridge housing  11015 . The grip member  11018  may be of any suitable configuration and optionally may be provided on other portions of the filter cartridge housing (for example as a ridge or groove in the sidewall). Alternatively, the filter cartridge housing  11015  need not include a separate grip member. 
     To help reduce the overall size of the surface cleaning apparatus, in the illustrated embodiment the pre-motor filter chamber  10956 , and the filters therein, is positioned above the cyclone chamber  10913  and covers the upper end of the cyclone chamber  10913 . In this configuration, a plane  10966  ( FIG. 44 ) containing the foam filter  10960  is generally parallel and spaced above a plane  10977  containing the air outlet  10923  of the cyclone chamber  10913 , and both planes  10966 ,  10967  are generally perpendicular to the cyclone axis  10920 . Arranging the filters  10960 ,  10961  in this configuration results in the upstream side of the pre-motor filter (in this example the upper side  10968  of the foam filter  10960 ) being spaced further apart from the cyclone chamber  10913  than the downstream side of the pre-motor filter (in this example the lower surface  10965  of the felt filter  10961 ). Alternatively, in other embodiments, the pre-motor filter chamber  10956  may cover only a portion of the upper end of the cyclone chamber and/or may be laterally spaced apart from the cyclone chamber. 
     When the surface cleaning apparatus is in use, air exiting the cyclone chamber  10913  can flow into the upstream head space  10970  via the vortex finder  10927 . Within the upstream headspace  10970  the air can flow laterally across the upstream surface  10968  of the foam filter  10960 , and down through the filters into the downstream head space  10964 . From the downstream head space  10964 , the air can flow to the inlet  10973  of the suction motor via an internal air conduit  10974  ( FIG. 44 ) formed within the body  10901 . In the illustrated embodiment, the internal air conduit  10974  is formed within the main body  10901  and is external the cyclone chamber  10913  and the dirt collection chamber  10914  and is partially bounded by an exterior surface exterior surface of the dirt collection chamber sidewall  10915 . The air conduit  10974  extends generally vertically between the pre-motor filter chamber  10956  and the suction motor  10911 , and is positioned laterally intermediate the suction motor  10911  and the cyclone chamber  10913 . The suction motor  10911  is positioned at an elevation where its air inlet  10973  is vertically between the upper and lower ends of the cyclone chamber  10913 , and the motor axis passes  10926  through the cyclone chamber  10913  and the dirt collection chamber  10914 . 
     Optionally, the cartridge member  11015  can be provided with a bottom cover  11030  to encase the filters  10960  and  10961  and to provide a self-contained pre-motor filter chamber  10956 . Referring to  FIGS. 51 and 52 , in such a configuration, the bottom cover  11030  may provide the bottom wall  10957  of the pre-motor filter chamber  10956 , and may be provided with internal ribs  10962  to support the filters  10960 ,  10961  and to provide the downstream headspace  10964 . An outlet port  11031  provided in the bottom cover  11030  allows air to exit the cartridge enclosure  11015  and flow into conduit  10974 . Providing a sealed cartridge may help further contain dirt within the cartridge prior to emptying, and may help keep the filters  10960  and  10961  in position. 
     Referring to  FIG. 38 , in the illustrated embodiment, handle  10902  has a first or bottom end  10981  that is adjacent the suction motor housing  10912 , a second or upper end  10982  that is spaced above from the lower end  1981  and a grip portion  10980  extending therebetween. When grasping the hand grip portion  10980 , a user&#39;s fingers may pass through an opening  10984 . 
     Referring to  FIG. 49 , a sectional view of an alternate embodiment cyclone bin assembly portion  12910  of a core cleaning unit  13000  that may be used by itself or with any other feature disclosed herein is exemplified. The cyclone bin assembly  12910  is similar to bin assembly  10910 , and like features are identified using like reference numerals indexed by 2000. The cyclone bin assembly  12910  is illustrated in isolation with the outer shell, filter cartridge member and the suction motor removed. In this embodiment the cyclone chamber  12913  is flared such that the cross-sectional area taken in a plane  13020  that passes through the air inlet  12922  (toward the bottom of the cyclone chamber  12913 ) is smaller than the cross-sectional area taken in a plane  13021  that passes through the dirt outlet  12924 , and is smaller than the cross-section area of the upper end wall  12937  of the cyclone chamber  12913  (which includes the air outlet  12923 ). In this configuration, the cyclone chamber sidewall  12921  includes a vertical portion  13022  and a generally frusto-conical portion  13023  positioned above the vertical portion  13022 . In this embodiment the volume of the cyclone chamber  12913  increases toward the top to the cyclone chamber, which may help improve cyclone efficiency and/or may help dis-entrained dirt exit via the dirt outlet. 
     Cyclone Bin Assembly 
     The following is a description of alternate cyclone bin assemblies, which may be used by itself or in any surface cleaning apparatus or in any combination or sub-combination with any other feature or features disclosed herein. 
     Referring to  FIG. 50 , a sectional view of an alternate embodiment cyclone bin assembly  14910  portion of the core cleaning unit  15000  that may be used by itself or with any other feature disclosed herein is exemplified. The cyclone bin assembly  14910  is similar to cyclone bin assembly  10910 , and like elements are represented using analogous reference numbers indexed by 4000. The cyclone bin assembly  14910  is illustrated in isolation with the outer shell, filter cartridge member and the suction motor removed. In this embodiment the cyclone chamber  14913  is tapered such that the cross-sectional area taken in a plane  15020  that passes through the air inlet  14922  (toward the bottom of the cyclone chamber  14913 ) is larger than the cross-sectional area taken in a plane  15021  that passes through the dirt outlet  14924 , and is larger than the cross-section area of the upper end wall  14937  of the cyclone chamber  14913  (which includes the air outlet  14923 ). In this configuration, the cyclone chamber sidewall  14921  includes a vertical portion  15022  and a generally inwardly-tapering frusto-conical portion  15023  positioned above the vertical portion. In this embodiment the volume of the cyclone chamber  14913  decreases toward the top to the cyclone chamber, which may help improve cyclone efficiency and/or may help dis-entrained dirt exit via the dirt outlet. 
     Referring to  FIG. 53 , a sectional view of an alternate embodiment cyclone bin assembly portion  16910  of a core cleaning unit  17000  that may be used by itself or with any other feature disclosed herein is exemplified. The cyclone bin assembly  16910  is similar to cyclone bin assembly  10910 , and like elements are represented using analogous reference numbers indexed by 6000. In this Figure, a pre-motor filter housing construction that may be used by itself or with any other feature disclosed herein is exemplified. 
     In the illustrated embodiment, a pre-motor filter chamber or housing  16956  is provided between the upper walls  16937 ,  16916  of the cyclone and dirt collection chambers  16913 ,  16914  and the openable cover (not shown). In this configuration, the bottom wall  16957  of the pre-motor filter chamber  10956  is integral with the upper walls  10937 ,  10916  of the cyclone  10913  and dirt collection chambers  10914 , and the upper wall  10958   a  and sidewall  10958  of the pre-motor filter chamber  10956  are provided via a filter cartridge housing  17015 . One or more filters may be positioned within the pre-motor filter chamber to filter fine particles from the air stream exiting the air outlet, before it flows into inlet of the suction motor. The filters may be of any suitable configuration and formed from any suitable materials. In the illustrated embodiment, a foam filter  16960  and a felt filter  16961  are positioned within the pre-motor filter chamber  16956 . 
     The pre-motor filters  16960 ,  16961  are shaped to fit within the cartridge member  17015 , and when inserted within the cartridge member the upstream side  16968  of the felt filter  16961  forms the bottom surface of the filter cartridge  11015 . When the filter cartridge  17015  is inserted in its use position (as shown) the upstream side  16968  of the pre-motor filter rests on the support ribs  16962  on the bottom wall  16957 , and the upstream headspace  16970  is defined between the upstream side  16968  of the filter  16960  and the bottom wall  16957 . 
     In this embodiment, the downstream headspace  16964  is provided between the downstream side  16965  of the pre-motor filter  16961  and the upper wall  10958   a  of the cartridge housing  11015 . Optionally, a plurality of spacing ribs  17016  can be provided on the inner surface of the upper wall  16958   a  to keep the downstream surface  16965  of the filter  16961  spaced apart from the inner surface of the upper wall  16958   a  to maintain the downstream headspace  16964 . 
     When the cyclone bin assembly  16910  is in use the upstream side  16968  of the filter  16960  may become soiled and/or partially blocked by dust and other relatively fine debris that is carried out of the cyclone chamber  16913 . If the upstream side  16968  becomes sufficiently blocked, airflow through the filter  16960  may be compromised and efficiency of the surface cleaning apparatus may decrease. 
     One method of cleaning the upstream side  16968  of the filter  16960  is for a user to remove the filter  16960  as described above, clean the surface  16968  and replace the filter  16960  within the pre-motor filter chamber  16956 . Alternatively, instead of removing the filter  16960  form the pre-motor filter chamber  16956 , the surface cyclone bin assembly  16910  may be configured to allow the filter  16960 , particularly the upstream side  16986 , to be cleaned in situ, without removing the filter  16960  from the pre-motor filter chamber  16956 . Dirt and debris may be extracted from the upstream side  16968  using any suitable mechanism, including, for example, banging to tapping the sides of the pre-motor filter chamber  16956  to dislodge the dirt and using a mechanical and/or electro-mechanical mechanism to help dislodge the debris. Examples of such mechanisms may include, for example, a scraper or other mechanical member that contacts and cleans the surface  16968  and a shaker or beater type of mechanism that can shake the filter  16960  to help dislodge the debris. 
     Optionally, the pre-motor filter chamber  16956  may be configured to receive fine dirt and debris from the upstream side  16968  and direct the debris into a fine particle collection chamber or pre-motor filter dirt chamber that can collect the dislodged debris. The fine particle collection chamber may be a portion of the primary dirt collection chamber  16914 , or may be provided as a separate chamber. 
     In the illustrated embodiment, the cyclone bin assembly  16910  includes a two pre-motor filter dirt chambers  17040   a  and  17040   b  for receiving debris  17041  that is dislodged from the upstream upside  16968  of filter  16960 . In the illustrated embodiment, the first dirt chamber  17040   a  is located within an extension member  17042 , which is inside the cyclone chamber  16913 . In this configuration, there is no communication between the first dirt chamber  117040   a  and the dirt chamber  16914 , nor do they share any walls or components in common. 
     The second dirt chamber  17040   b  is provided outside and adjacent the dirt chamber. The second dirt chamber  17040   b  is partially bounded by the sidewall  16915  of the primary dirt collection chamber  16914 , but is external the chamber  16914  and includes a sidewall  17043 . The second dirt collection chamber  17040   b  has a bottom wall  17044  that is pivotally connected to the cyclone bin assembly  16910 . The bottom wall  17044  can be opened and closed independently of the bottom walls  16917  and  16943  of the dirt collection chamber  16914  and cyclone chamber  16913  respectively. 
     In the illustrated example, the bottom wall  16957  of the pre-motor filter chamber  16956  (which is coincident with the upper wall  39  of the cyclone chamber  10  in this example) is inclined from left to right as illustrated. Sloping the wall  16957  in this manner may help guide the debris  17041  that falls from the left side of the filter  16960  (as illustrated) toward the air outlet  16923 , and may guide debris that is positioned to the right of the air outlet  16923  (as illustrated) toward to second dirt chamber  17040   b . When the air flow through the cyclone chamber  16913  is off (i.e. when the cyclone bin assembly  16910  is removed and/or when the surface cleaning apparatus is off), some of the debris  17041  may fall downwardly though the vortex finder  16927 , through air outlet  16923 , pass through the interior of the screen  16928  and fall into the dirt chamber  17040   a . Because the dirt chamber  17040   a  is positioned below the air flow openings in the screen  16928  it may be a relatively low air flow region when the surface cleaning apparatus is in use. This may allow debris  17041  that has accumulated dirt chamber  17041  to remain in the dirt chamber  17040   a  if the surface cleaning apparatus is used prior to emptying the dirt chamber  17040   a , as it is unlikely that the debris  17041  will be re-entrained in the air flowing into the screen  16928  and upwardly though the air outlet  16923 . 
     Similarly, in the absence of strong air flow, some of the debris  17041  may collect at the bottom of dirt chamber  17040   b . Like chamber  17040   a , chamber  17040   b  is provided below and generally outside the primary air flow path through the cyclone bin assembly  16910 . This may allow debris  17041  to remain contained in dirt chamber  17040   b  if the cyclone bin assembly  16910  is operated before emptying dirt chamber  17040   b.    
     The dirt chamber  17040   a  includes a sidewall  17046  and a bottom wall  17047 . The top of the chamber  17040   a  is open to receive the debris  17041 . In the illustrated embodiment the bottom wall  17047  of the dirt chamber  17040   a  is a cap member that is distinct from the floor  16943  of the cyclone chamber  16913 . In this configuration, opening the door  16943  simultaneously opens the cyclone chamber  16913 , the dirt chamber  16914  but does not automatically open the pre-motor filter dirt chamber  17040   a . To empty the dirt chamber  17040   a , the user can remove the bottom wall  17047 . This allows a user to decide when to empty the dirt chamber  17040   a  independently from the cyclone chamber  16913  and the dirt chamber  16914 . Alternatively, the dirt chamber  17040   a  need not include a separate bottom wall member  17047 , and the bottom of the dirt chamber  17040   a  can be sealed by the bottom wall  16943  of the cyclone chamber  16913 . In such a configuration, the dirt chamber  17040   a  would be opened with the cyclone chamber  16913 . The bottom wall  17044  is not operatively connected to the bottom walls  16917  and  16943 , and therefore chamber  17040   b  is openable independently from dirt chamber  17040   a , cyclone chamber  16913  and dirt chamber  16914 . 
     Optionally, the cyclone bin assembly  16910  may include an additional dirt collection chamber that is positioned within the pre-motor filter chamber  16956 . Referring to  FIG. 54 , the cyclone bin assembly  16910  is illustrated containing a removable dirt collection chamber  17040   c  positioned within the pre-motor filter chamber  16956 . The dirt collection chamber  17040   c  is a cup-like member that can collect a portion of the debris  17041  that falls from the filter  16960 . Providing a third chamber  17040   c  may help reduce the amount of debris that accumulates within chambers  7040   a  and  17040   b . In the illustrated configuration, the dirt chamber  17040   c  is not emptyable like chambers  17040   a  and  17040   b  and does not include any type of openable door. Instead, the dirt chamber  17040   c  is removably seated within the pre-motor filter chamber  16956  and can be removed for emptying when the filters  16960  and  16961  are removed by the user. 
     In these examples, debris  17041  may be dislodged from the filter  16960  by shaking or banging the cyclone bin assembly  16910 . Alternatively, a filter cleaning mechanism can be included within the pre-motor filter chamber  16956 . 
     Referring to  FIG. 55 , another embodiment of a cyclone bin assembly  18910  is exemplified having an example of a filter cleaning mechanism  19060 , which may be used in combination with any other suitable cyclone bin assembly described herein. In the illustrated embodiment, the filter cleaning mechanism  19060  is provided in the form of a rotating sweeper apparatus  19061  that includes a pair of sweeper arms  19062  that can scrape the upstream surface  18968  of the filter  18960 . The sweeper arms  19062  may be of any suitable configuration, and may be formed from any suitable material including, for example, plastic and metal. 
     The sweeper arms  19062  are connected to a central hub  19063  which is mounted to shaft  19064 . Shaft  19065  is driven by electric motor  19065  and rotates about axis  19066 . The motor  19065  is mounted to one of the support ribs  18962  within the upstream head space  18970 . Additional ribs surrounding the filter cleaning mechanism  19060  may include cut-outs to allow the sweeper arms  19062  to pass. Alternatively, instead of completing full revolutions the motor  19065  may be configured to oscillate back and forth. 
     Providing the filter cleaning mechanism in the upstream headspace  18970  may be advantageous as it allows the sweeper arms  19062  to directly engage the upstream surface  18968 . 
     The motor  19065  may be supplied with power from any suitable source, including the external power source and/or an onboard power storage device, such as batteries. Providing batteries may be advantageous as it may allow the filter cleaning mechanism  19069  to be operated when the surface cleaning apparatus is unplugged. 
     Alternatively, instead of providing a motor  19065 , the shaft  19064  may be rotatably or pivotally supported by bearings or bushings within the pre-motor filter chamber  18956 , but need not have a drive mechanism. In such a configuration, the sweeper arms  19062  may be moved across the surface  18968  of the filter  18960  when a user shakes or bangs the outside of the cyclone bin assembly  18910 . In this configuration, the filter cleaning mechanism  19060  may amplify the user&#39;s input force and use that force to clean the filter  18960 . In yet another alternative configuration, an external crank or actuator may be provided to allow a user to manually rotate the shaft  19064  and sweeper arms  19062 . 
     Also of note in this embodiment, the bottom walls  19044  and  19047  of the pre-motor filter dirt chambers  19070   b  and  19070   a  are both integral with walls  18917  and  18943 . In this configuration, the pre-motor filter chambers  19040   a  and  19040   b , the cyclone chamber  18913  and dirt chamber  18914  are simultaneously openable. 
     Referring to  FIG. 56 , the cyclone bin assembly  18910  is illustrated containing another embodiment of a filter cleaning mechanism  19060 , which may be used in isolation or in combination with any other features herein. In this embodiment, the filter cleaning mechanism  19060  includes a motor  19065  that is mounted to the upper wall  18958  of the cartridge housing  19015  and is positioned within the downstream headspace  18964 . The motor  19065  includes an output shaft  19064  that is coupled to an eccentrically mounted beating member  19070 . The beating member  19070  can be formed from any suitable material (e.g. plastic and metal) and can be of any suitable shape. 
     In the illustrated embodiment the beating member is a generally cylindrical member mounted eccentrically on the shaft  19064 . As the shaft rotates the beating member  19070  will periodically impact the downstream side  18965  of filter  18961 . The impact on the surface of filter  18961  may produce vibrations in filter  18961 , and the vibrations may be transferred to filter  18960 . Vibrations in filter  18960  may tend to dislodge debris from the upstream side  18968  of the filter  18960 , and into the dirt collection chambers  194040   a  and  19040   b . The motor  19065  may be powered using any suitable source as described herein. 
     What has been described above has been intended to be illustrative of the invention and non-limiting and it will be understood by persons skilled in the art that other variants and modifications may be made without departing from the scope of the invention as defined in the claims appended hereto. The scope of the claims should not be limited by the preferred embodiments and examples, but should be given the broadest interpretation consistent with the description as a whole.