Patent Publication Number: US-9901228-B2

Title: Surface cleaning apparatus with different cleaning configurations

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of co-pending U.S. patent application Ser. No. 13/255,885, entitled SURFACE CLEANING APPARATUS WITH DIFFERENT CLEANING CONFIGURATIONS, which application is, in accordance with 35 USC 371, a national phase entry of International Patent Application No. PCT/CA2010/00365, filed Mar. 12, 2010 and entitled SURFACE CLEANING APPARATUS WITH DIFFERENT CLEANING CONFIGURATIONS, which application claims priority from co-pending Canadian patent application nos. 2,674,376, filed Jul. 30, 2009, and 2,658,377, filed Mar. 13, 2009. Each of these applications is incorporated herein in its entirety by reference. 
    
    
     FIELD 
     The specification relates to surface cleaning apparatus. In a preferred embodiment, the surface cleaning apparatus has a portable surface cleaning unit, such as a hand vacuum, that is selectively detachable from a support structure and may be selectively connected to a surface cleaning head by an airflow conduit. 
     INTRODUCTION 
     The following is not an admission that anything discussed below is prior art or part of the common general knowledge of persons skilled in the art. 
     Various types of surface cleaning apparatus are known. Typical upright vacuum cleaners include an upper section, including an air treatment member such as one or more cyclones and/or filters, drivingly mounted to a surface cleaning head. An up flow conduit is typically provided between the surface cleaning head and the upper section. In some such vacuum cleaners, a spine, casing or backbone extends between the surface cleaning head and the upper section for supporting the upper section. The air treatment member or members and/or the suction motor may be provided on the upper section. 
     Surface cleaning apparatus having a portable cleaning module that is removably mounted to an upright vacuum cleaner are known. See for example, U.S. Pat. No. 5,309,600. In addition surface cleaning apparatus having a removably mounted hand vacuum cleaner are also known. See for example U.S. Pat. No. 4,635,315. 
     SUMMARY 
     The following introduction is provided to introduce the reader to the more detailed discussion to follow. The introduction is not intended to limit or define the claims. 
     According to one broad aspect, an upright vacuum cleaner is provided that comprises a support structure drivingly connected to a surface cleaning head. A cleaning unit is selectively detachably mounted to the support structure and may be selectively connectable in fluid communication with the surface cleaning head by an airflow conduit. A mount that permits one handed operation by a user to remove the cleaning unit from the support structure is provided. For example, the cleaning unit may be held in place by gravity when in the storage position and, optionally, also when in a floor cleaning position. Preferably, the mount permits for sliding engagement between the cleaning unit and the support structure that supports the cleaning unit. The cleaning unit is preferably vertically removable from the mount. Accordingly, the cleaning unit may seat on a mount spaced from a floor cleaning head and remain in place until lifted off even if the cleaning unit is not locked in place. 
     Accordingly a user may use one hand to lift the portable surface cleaning unit of the surface cleaning apparatus while still operating the surface cleaning apparatus with the user&#39;s other hand. Optionally, a lock may be provided. In such a case, the lock is preferably operated using a single hand and the portable surface cleaning unit preferably remains in position when the lock is disengaged so that a user may use the same hand to release the lock and to then remove the portable surface cleaning unit. 
     During operation, dirt is entrained in an air stream that is drawn into a dirty air inlet, preferably at the front of the surface cleaning head. During the operation of the surface cleaning apparatus, the cleaning unit may be removed from the mount and held by the user while still in airflow communication with the surface cleaning head (i.e. without interrupting the operation of the surface cleaning apparatus). 
     The cleaning unit may be slidingly received within the mount and vertically held within the mount by gravity, absent any mechanical fasteners. In this type of gravity mount, the cleaning unit is freely removable from the mount without having to release or open any fasteners. This gravity mount configuration enables a user to quickly and easily remove the cleaning unit from the mount using a single hand. 
     Optionally, the cleaning unit can be detached from the surface cleaning head and may receive an auxiliary cleaning tool. Accordingly, the cleaning unit may be converted to use a different cleaning tool to clean, e.g., a floor. For example, an air turbine powered brush may be selectively mounted to the cleaning unit. Alternately, or in addition, an above floor cleaning tool, e.g., an attachment that includes a flexible hose to which a cleaning tool may be mounted at the end distal to the nozzle, may be used. Accordingly, the cleaning unit may be adapted for additional cleaning uses. Essentially, a removable attachment may be employed to convert an open sided nozzle to a traditional nozzle with a traditional dirty air inlet. Alternately, the nozzle may be connectable with a surface cleaning head of an upright vacuum cleaner. 
     In one embodiment, an upright surface cleaning apparatus includes an air flow path extending from a dirty air inlet to a clean air outlet and a surface cleaning head having the dirty air inlet. The surface cleaning apparatus also includes a support structure moveably mounted to the surface cleaning head and a cleaning unit comprising a suction motor and an air treatment member. The cleaning unit is positioned in the air flow path and is removably mountable. A lock may releasably lock the cleaning unit on the support structure and the cleaning unit and the support structure may be configured to retain the cleaning unit on the support structure when the lock is in a locked position. 
     In some examples, the cleaning unit and the support structure are configured to retain the cleaning unit on the support structure in a storage position under the influence of gravity. 
     In some examples the surface cleaning apparatus also includes a lock that releasably locks the cleaning unit on the support structure. The cleaning unit and the support structure are configured to retain the cleaning unit on the support structure when the lock is in an unlocked position. 
     In some examples, the cleaning unit has a bottom and the bottom is spaced from the surface cleaning head when the cleaning unit is mounted to the support structure. 
     In some examples, the cleaning unit is supported only by the support structure. 
     In some examples, the upright surface cleaning apparatus may further comprise an attachment member, the cleaning unit is removably mountable on a mount provided on the support structure, the attachment member and the mount is configured such that the cleaning unit is removable from the mount in the absence of disengaging a lock. 
     The cleaning unit may be removably mountable on the mount, the attachment member and mount may be configured such that the cleaning unit is removable from the mount in the absence of disengaging a lock. 
     In some examples, the mount has a first contact member and the attachment member has a second contact member, the second contact member is downwardly slidably engagable with the first contact member and abutment of the first and second contact members restrains movement of the cleaning unit in a forward direction of travel and a direction transverse to the forward direction of travel and the vertical. 
     In some examples, at least one of the contact members includes a cam surface. 
     In some examples, one of the contact members comprises a cam surface and the other of the contact members comprises a cam. 
     In some examples, one of the contact members comprises a pair of opposed spaced apart sides defining a channel between the opposed sides, at least one of the opposed sides having an open portion, and the other of the contact members comprises an abutment member sized to be received in the channel, the abutment member having opposed sidewalls spaced apart by a distance, each sidewall facing one of the opposed sides and a distance between the sidewalls and the opposed facing walls decreases from an upper end of the abutment member to a lower portion of the abutment member. 
     In some examples, the open portion comprises a portion of the front of the one of the contact members. 
     In some examples, the cleaning unit comprises an attachment member, the second contact member is provided on the attachment and the attachment member extends outwardly through the open portion. 
     In some examples, the attachment member is removably mounted on the cleaning unit. 
     In some examples, the attachment member is removably mounted on the cleaning unit using a complimentary tongue and groove connection. 
     In some examples, the attachment member comprises part of an air flow path from the surface cleaning head to the cleaning unit. 
     In some examples, a mount provided on the support structure and the attachment member are configured to retain the cleaning unit on the support structure under the influence of gravity during operation of the upright surface cleaning apparatus. 
     In some examples, the attachment member is vertically removable from the support structure. 
     In some examples, an air flow path from the surface cleaning head to the cleaning unit comprises a flexible air flow conduit. 
     In some examples, the upright surface cleaning apparatus has at least two operating modes comprising a first upright operating mode wherein the upright surface cleaning apparatus is operable with the cleaning unit mounted to the support structure and forming part of the air flow path and a second operating mode wherein the cleaning unit is operable when removed from the support structure. 
     In some examples, in the second mode, the cleaning unit is operable when removed from the support structure and in air communication with the surface cleaning head. 
     In some examples, an air flow path from the surface cleaning head to the cleaning unit comprises a flexible air flow conduit. 
     In some examples, the cleaning unit is operable when disconnected from the surface cleaning head. 
     In some examples, the cleaning unit is mounted to the support structure at a midpoint of the support structure. 
     In some examples, the support structure comprises a further portion that also retains the cleaning unit on the support structure. 
     In some examples, the further portion is below the first contact member. 
     In some examples, the further portion engages a wheel of the cleaning unit. 
     In some examples, the attachment member and a mount provided on the support structure comprise a releasable securing mount and the releasable securing mount further comprises at least one magnet. 
     In some examples, the cleaning unit is supported on an airflow conduit of the support structure. 
     It will be appreciated that an embodiment may contain one or more of features set out in the examples. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       In the detailed description, reference will be made to the following drawings, in which: 
         FIG. 1  is a front elevation view of an example of a vacuum cleaner; 
         FIG. 2  is a back perspective view of the vacuum cleaner of  FIG. 1  with a portable surface cleaning apparatus mounted to a support structure; 
         FIG. 3 a    is a back perspective view of the vacuum cleaner of  FIG. 1  with the portable surface cleaning apparatus removed from the support structure and in a position in which it may be carried by hand; 
         FIG. 3 b    is a side elevation view of the portable surface cleaning apparatus of  FIG. 3 a    wherein the portable surface cleaning apparatus has been removed from the support structure and is in a position in which it may be carried by hand with flexible hose detached from the surface cleaning head; 
         FIG. 4  is a partially exploded side perspective view of the vacuum cleaner of  FIG. 1  with the portable surface cleaning apparatus removed from air flow communication with the floor cleaning unit; 
         FIG. 5  is a front isometric view of the vacuum cleaner of  FIG. 1  with the portable surface cleaning apparatus removed; 
         FIG. 6  is side elevation view of a hand vacuum cleaner; 
         FIG. 7  is a front elevation view of the hand vacuum cleaner of  FIG. 6 ; 
         FIG. 8  is a bottom isometric view the hand vacuum cleaner of  FIG. 6 ; 
         FIG. 9  is a bottom isometric view of the hand vacuum cleaner and an attachment member; 
         FIG. 10  is a partially exploded bottom isometric view of the hand vacuum cleaner and an attachment member of  FIG. 9 ; 
         FIG. 11  is a side isometric view of the attachment member of  FIG. 9 ; 
         FIG. 12  is a front elevation view of the attachment member of  FIG. 11 ; 
         FIG. 13  is a side isometric view of the attachment member of  FIG. 11 ; 
         FIG. 14  is a partially exploded isometric view of the attachment member of  FIG. 11 ; 
         FIG. 15  is a front isometric view of an alternate example of a vacuum cleaner with a portable surface cleaning apparatus mounted thereto; 
         FIG. 16  is a partial rear isometric view of the vacuum cleaner of  FIG. 15 ; 
         FIG. 17  is a rear isometric view of an alternate example of a vacuum cleaner with a portable surface cleaning apparatus mounted thereto; 
         FIG. 18  is a partial front isometric view of the vacuum cleaner of  FIG. 17  with the portable surface cleaning apparatus removed; 
         FIG. 19  is a partial top view of the surface cleaning head of the vacuum cleaner of  FIG. 17 ; 
         FIG. 20  is a side elevation view of an alternate example of a vacuum cleaner with a portable surface cleaning apparatus mounted thereto; 
         FIG. 21  is a cross-section view of the vacuum cleaner of  FIG. 20 ; 
         FIG. 22  is a front isometric view an alternate example a vacuum cleaner with a hand vacuum cleaner mounted thereto; 
         FIG. 23  is a front view of the vacuum cleaner of  FIG. 22  with the hand vacuum cleaner removed; 
         FIG. 24  is a side elevation view of the vacuum cleaner of  FIG. 22 ; 
         FIG. 25  is a side elevation view of the vacuum cleaner of  FIG. 22  with the portable surface cleaning apparatus removed from the floor cleaning unit; 
         FIG. 26  is a side elevation view of the vacuum cleaner of  FIG. 22  with the portable surface cleaning apparatus separated from the flexible hose  124 ; 
         FIG. 27  is a rear isometric view of an alternate example of an attachment member; 
         FIG. 28  is a front isometric view of the attachment member of  FIG. 27 ; 
         FIG. 29  is an exploded view of the attachment member of  FIG. 27 ; 
         FIG. 30  is a rear isometric view of a locking knob; 
         FIG. 31  is a isometric view of the attachment member of  FIG. 27  in use on the vacuum cleaner of  FIG. 22 ; 
         FIG. 32  is an isometric view of the attachment member of  FIG. 31  with the shell seated on the mount and the knob in an unlocked position; 
         FIG. 33  is an isometric view of the attachment member of  FIG. 32  with the shell seated on the mount and the knob in the locked position; 
         FIG. 34  is a front elevation view of an another example of a vacuum cleaner wherein the cleaning unit has been removed for hand held use; and, 
         FIG. 35  is a top perspective view of the motor housing of the vacuum cleaner of  FIG. 34 . 
     
    
    
     DESCRIPTION OF VARIOUS EXAMPLES 
     Various apparatuses or methods will be described below to provide an example of each claimed invention. No example described below limits any claimed invention and any claimed invention may cover processes or apparatuses that are not 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. 
     The following description describes various embodiments of an upright surface cleaning apparatus, for example an upright vacuum cleaner. The upright surface cleaning apparatus generally comprises a support structure or upright section that is movably connected to a surface cleaning head. In accordance with a first aspect, the support structure may be of any particular design that is flexible or bendable at a location between the upper end and the lower end of the support structure when in use. Preferably, the support structure includes a hinge that pivotally connects an upper and lower portion of the support structure. 
     Referring to  FIGS. 1 to 5, 15 to 19, 20 to 21 and 22 to 33 , examples of an upright surface cleaning apparatus  100  are shown which exemplifies the design using a hand vacuum cleaner  400 . The surface cleaning apparatus  100  is a vacuum cleaner that comprises a floor cleaning unit  200  comprising a surface cleaning head  300  having a support structure  210  pivotally mounted thereto and a hand vacuum cleaner  400  that is removably mounted to support structure  210 . Support structure  210  may also be referred to as a handle, a backbone or an upright section. In this specification, the terms portable surface cleaning apparatus, cleaning unit and hand vacuum are used alternately to refer to the hand vacuum cleaner  400 . 
     It will be appreciated that in each example, the surface cleaning apparatus  400  need not be a portable cleaning unit having a dirty air inlet for cleaning a surface. Instead it may be a cleaning unit that houses a suction motor and one or more air treatment members wherein the cleaning unit may be of any construction and may use any particular air treatment member (e.g., one or more cyclones comprising one or more cyclonic cleaning stages and/or one or more filters). Such a cleaning unit does not have a dirty air inlet adapted to clean a floor. Instead, it is configured to receive dirty air conveyed from floor cleaning unit  300 . For example, the cleaning unit may be detachable from the support structure  210  as exemplified in  FIG. 3 a    and  FIG. 25  but flexible hose  124  may not be removable from the cleaning head or the cleaning unit. The support structure  210  (or other elements) may also comprise cord wind members  219  (as exemplified in  FIGS. 17 and 22 ) for winding the power cord of the vacuum cleaner  100  when not in use. 
     In accordance with the first aspect, the support structure comprises first and second portions wherein the second portion is rotatable relative to the first portion about an axis that intersects a longitudinal axis of at least one of the first and second portions. 
     As exemplified in  FIGS. 1-5, 15-19, 20-21 and 22-33 , the support structure  210  (also referred to as the handle  210 ) has an upper portion  214  and a lower portion  216  that are preferably pivotally connected by a hinge  218 . Any type of hinge, pivot or bending mechanism known in the vacuum cleaner arts may be used provided that grip  212  may be moved forwardly with respect to the upper end of lower portion  214 . The handle  210  is attached to the surface cleaning head  300  and a user can move the surface cleaning head  300  along a surface to be cleaned by gripping and maneuvering the handle  210 . Optionally, the lower portion  216  of the handle  210  may be moveably, e.g., hingedly or pivotally, attached to the surface cleaning head  300 , so that the lower portion  216  of the handle  210  can move relative to the surface cleaning head  300  during use. This may enable the user to move the surface cleaning head  300  beneath cabinets, furniture or other obstacles. 
     The upper portion  214  of the handle optionally includes a handgrip or grip  212  that is shaped to be gripped by a user. In the example shown, the grip  212  is at the top, or upper end of the upper portion  214  of the handle  210  and is formed in a closed loop-type shape having surfaces that are rounded to increase user comfort. In other examples, the grip  212  may be of a different configuration and may be located at a different position on the upper portion  214  of the handle  210 . 
     Alternately, or in addition, the upper portion  214  of the handle  210  optionally includes a bracket  113 , as exemplified in  FIGS. 1-5 , which supports an auxiliary, or accessory or supplemental cleaning tool  112 . In the example shown, the bracket  113  is configured to hold a single auxiliary cleaning tool  112 , but in other examples the bracket  113  may be configured to hold more than one auxiliary cleaning tool  112 . Also, while shown attached to the upper portion  214 , it is understood that the bracket  113  may be attached to other locations on the surface cleaning apparatus, including the lower portion  216  as exemplified in  FIGS. 17 and 20 , the surface cleaning head  300  and/or the hand vacuum cleaner  400 . 
     Optionally, the cleaning unit is not retrained within, e.g., a recess, in an outer housing or other portion of the support structure. As exemplified in  FIGS. 1-5, 15-19, 20-21 and 22-33 , an upright vacuum cleaner  100  has an absence of a housing or shell that has traditionally been used with upright vacuum cleaners. For example, no molded plastic shell is provided that houses operating components of the vacuum cleaner and includes a recess for receiving the hand vacuum cleaner  400 . Instead, as exemplified, one or more support rods or structural members may be used, e.g., one as exemplified in  FIGS. 1-5, 20-21 and 22-33  or two as exemplified in  FIGS. 15-19 , so as to define a frame to removably receive the cleaning unit. In such an embodiment, the support rods may define a frame for removably receiving the cleaning unit. As exemplified, preferably the support rods or structural members that form the upper and lower portions  214 ,  216  have a generally cylindrical or tube-like shape. However, in other examples, the upper and lower portions  214 ,  216  may be any other type of relatively thin or elongated support members having suitable cross-sectional shape including square, rectangular or polygonal. In addition, the upper and lower portions  214 ,  216  may be solid or hollow and may be formed from any suitable material, including plastic and metal. If one or both of the upper and lower portions  214 ,  216  are hollow, then the hollow portion may form part of the air flow path through the vacuum cleaner, as exemplified in  FIGS. 22-33 . 
     When the hinge  218  is in a first position, as shown in  FIGS. 1, 2, 4, 5, 15, 16, 20, 22 and 24-26  the upper and lower portions  214 ,  216  of the handle  210  are generally aligned with each other, e.g., they each have a longitudinal axis and the axis are generally parallel. As exemplified in  FIGS. 15  and  21 , the axis of the upper portion  214  may be located forward of the axis of the lower portion  216 . The hinge  218  is preferably retained in this first position by a biasing or locking means so that the upper portion  214  of the handle  210  preferably remains at a fixed angular position with lower portion  216  when the lock is engaged so that forward and rearward movements applied to grip  212  of the upper portion  214  of the handle  210  can be translated to the second portion  216  as is known conventionally. In use, the hinge  218  can be unlocked, or released from the first position and upper portion  214  may be moved into one or more second fixed positions, wherein the grip  212  is preferably rotated forwardly. Optionally, the lock may remain in the unlocked position such that upper portion  214  may freely rotate with respect to the lower portion  216  while it is used to move the cleaning head. 
     As exemplified in  FIGS. 1, 2, 4, 5, 15, 17 and 20-23 , the grip  212  preferably comprises an actuator for releasing or unlocking the releasable lock or hinge  218 , for example a button or hinge release  213  that can be activated by a user during use of vacuum cleaner  100  to unlock the hinge  218 . It will be appreciated that the actuator may be of any type and may be located at any location and is preferably provided on the upper portion and is preferably adjacent the grip  212 . When a user activates the hinge release  213 , the retaining or locking means used to secure the hinge  218  in the first position is disengaged, allowing the hinge  218  to rotate or pivot, as shown in  FIGS. 3 a    and  17 . As the hinge  218  rotates, the first portion  214  of the handle  210  can be moved into a plurality of angular positions relative to the second portion  216  handle  210 . Optionally, the hinge  218  may rotate between, and lock into, one or a given number of set or indexed angular positions. Alternatively, the rotation of the hinge  218  may be continuously variable, after being initially unlocked, allowing for the first portion  214  to be moved into an indefinite number of angular positions relative to the second portion  216  (e.g., freely rotatable). 
     The upright surface cleaning apparatus also includes a cleaning unit, for example hand vacuum cleaner  400 . The cleaning unit is attached to and supported by the support structure  210 . Preferably, the cleaning unit is removably mounted to the support structure and it may be detachably mounted thereto. Preferably, the cleaning unit is removable from support structure  210  while still in air flow communication with the cleaning head  300 . Accordingly an attachment member  120  may be used to provide both a member to removably attach the cleaning unit to support structure  210  and an air flow connection when the cleaning unit is removed with the attachment member  120 . 
     In the examples shown, the hand vacuum cleaner  400  is attached to the support structure  210  using a mount apparatus, for example mount  220 . Preferably, instead of connecting directly to the hand vacuum cleaning  400 , the mount apparatus is configured to receive a complimentary attachment apparatus, for example attachment member  120 , which is connected, and preferably removably connected, to the hand vacuum cleaner  400 . Preferably, as exemplified in  FIGS. 1, 2, 4, 5, 15-19, 20-21 and 22-33 , the lower portion  216  comprises the mount  220  for supporting the hand vacuum cleaner  400 . It will be appreciated that, alternately, mount  220  may be provided on upper portion  214 . 
     Hand vacuum cleaner  400  is preferably connected in fluid communication with the cleaning head  300  by a conduit that comprises, and may consist of, a flexible hose. In such a case, the lower portion  216  also optionally comprises a hose guide  230 , as exemplified in  FIGS. 1, 2, 4 and 5  for keeping the flexible hose  124  in close proximity to the support structure  210 . When the hand vacuum cleaner  400  is detached or removed from the support structure  210  the flexible hose  124  may be removed from the hose guide  230 , as shown in  FIG. 3 a   . In another example, as exemplified in  FIGS. 15-19, 20 and 22-26 , a hose guide may not be included when the upstream end of the flexible hose  124  is connected in air flow communication with an upper end of the lower portion  216  instead of directly to the surface cleaning head  300 . 
     In a second aspect, which may be used by itself or with any one or more other aspects, and with or without a bendable wand, examples of the upright vacuum cleaner  100  may be operated in one or more of the following three functional configurations or modes. The versatility of operating in different modes is achieved by permitting hand vacuum cleaner  400  to be removed from support structure  210  with or without attachment member  120 . Alternately, or in addition, further, versatility is achieved by permitting flexible hose  124  to be disconnectable from attachment member  120  and/or the cleaning head  300 . 
     In the first configuration, as exemplified in  FIGS. 1, 2, 17 and 24 , the vacuum cleaner  100  can be operated with the hand vacuum cleaner  400  mounted to the lower portion  216  of the floor cleaning unit  200 . In this configuration the hand vacuum cleaner  400  is supported by the support structure  210  and the vacuum cleaner  100  can be operated as an upright vacuum cleaner. In this configuration, the hand vacuum cleaner  400  is attached to the support structure  210  using, e.g., an attachment member  120  (examples of attachment members are described in greater detail below). In some examples, a portion of the load of the hand vacuum cleaner  400  is optionally also supported by a mount bracket  224 , which receives and supports another part of surface cleaning apparatus  400 , such as optional rear wheel  480  of the surface cleaning apparatus  400 . 
     In a second configuration, as exemplified in  FIGS. 3 a    and  25 , the surface cleaning apparatus  400  is detached from the support structure  210  but remains in fluid communication with the surface cleaning head  300  via, e.g., flexible hose  124  and attachment member  120 . In this configuration, the hand vacuum cleaner  400  may be carried by the user (or rested on the floor or other surface) while still serving as the vacuum or suction source for the vacuum cleaner  100 . 
     In the third configuration, as exemplified in  FIGS. 3 b   ,  4  and  26 , the surface cleaning apparatus  400  is detached from the support structure  210  and from fluid communication with surface cleaning head  300 . The cleaning unit may have a nozzle and be a portable surface cleaning apparatus, such as a hand vacuum cleaner. As exemplified in  FIGS. 4 and 26 , the hand vacuum cleaner  400  may be uncoupled from the attachment member  120  (which remains attached to the support structure  210 ) and can be used independently as a portable cleaning apparatus or a hand vacuum. 
     Optionally, as exemplified in  FIG. 3 b   , the surface cleaning apparatus  400  is detached from the support structure  210  and from fluid communication with surface cleaning head  300  by detaching flexible hose  124  from the surface cleaning head  300 . Accordingly, flexible hose  124  serves as an extended cleaning attachment for the hand vacuum cleaner  400 . Optionally, one or both ends of flexible hose  124  may be disconnectable from the surface cleaning apparatus. 
     Accordingly, if the attachment member  120  is coupled to the hand vacuum cleaner  400 , and the upstream end of the air conduit  110  (for example hose  124 ) is detached from the surface cleaning head  300 , then the combination of the attachment member  120  and the flexible hose  124  (decoupled from the surface cleaning head  300 ) may serve as an auxiliary or accessory cleaning tool. The free end of the hose  124  may be maneuvered by the user to clean objects and surfaces that cannot be cleaned using the surface cleaning head  300 . In some examples, the upstream end of the flexible hose  124  may be connected to the auxiliary cleaning tool  112 . Alternatively, the flexible hose  124  may be removed from the attachment member  120  and the auxiliary cleaning tool  112  may be mounted directly to the air inlet  126  of the attachment member  120 . It will be appreciated that tool  112  may have a plate  123  and arms  150  provided at the coupling end thereof. 
     Optionally, the attachment member  120  may be removed from the hand vacuum cleaner  400  and the auxiliary cleaning tool  112  may be fitted directly to the nozzle  412  (shown in  FIGS. 6-10 ), without the use of a flexible hose  124  or other type intermediate air conduit. In addition to the auxiliary or accessory cleaning tool  112 , the nozzle  412  may be directly connected to any one of a number of cleaning tools that have been provided with the an appropriate attachment member, including wands, brushes, crevasse tools and other hoses. 
     Optionally, a cleaning wand  114  may be attached to the upstream end of the flexible hose  124 , as exemplified in  FIG. 20 . The addition of the cleaning wand  114  to the end of the flexible hose  124  may enable a user to reach further (for example to the top of drapes or curtains) or to extend the airflow conduit  110  into confined spaces (for example between couch cushions or under cabinets and appliances). When assembled as shown in  FIG. 24 , the upright vacuum cleaner configuration, the dirty air travels from the cleaning head  300  through lower portion  216  (which is the up flow duct), through hose  124  and into attachment member  120 . 
     In some examples, the cleaning wand  114  may be shaped so that it can be received within or in air flow communication with an upper opening  286  of the lower portion  216  of the support structure  210 , as exemplified in  FIG. 22 . In these examples, when the cleaning wand  114  is not in use it can be received within, and thereby stored within the lower portion  216  of the support structure  210  (not shown) or maybe mounted to upper end of lower portion  216  and form part of the support structure  210 . In other examples, the cleaning wand  114  may be elsewhere and flexible hose  124  may be connected directly to upper opening  286 . 
     In any of the examples described above, the air conduit  110  (for example flexible hose  124  and/or wand  114 ) may still be detachable from the surface cleaning head  300  even when the cleaning unit is not detachable from the support structure. Accordingly, some or all of air conduit may be detachable from the surface cleaning head  300  whether or not the hand vacuum cleaner  400  is detachable from the support structure  210  to enable a user to use the flexible hose  124  and/or the wand  114  to clean surfaces that are awkward to clean using the surface cleaning head  300 , for example upholstery, drapes, stairs and other, non-level, confined or elevated surfaces. 
     As exemplified in  FIG. 22 , in a preferred embodiment, the lower portion  216  is hollow and forms part of the airflow passage through the vacuum cleaner. Accordingly, lower portion  216  functions as both an air flow conduit and a support structure on which surface cleaning apparatus  400  is mounted. If a rigid cleaning wand  114  is not required, then the dirty air may travel from lower portion  216  directly into surface cleaning apparatus  400 , e.g., via attachment member  120 . Alternately, if a cleaning wand  114  is provided, then as exemplified, the dirty air may travel from the upper end of lower portion  216  into wand  114 , into flexible hose  124 , through optional attachment member  120 , and then into surface cleaning apparatus  400 . 
     To provide the user with increased reach and cleaning range, the cleaning wand  114  may be more rigid than the flexible hose  124 , and is preferably rigid, so that the cleaning wand  114  will maintain its generally elongate configuration (that is the upstream end of the cleaning wand being separated from but generally concentric with the downstream end of the cleaning wand), even when it is only held at one end by the user. In some instances, the cleaning wand  114  may be substantially rigid so that it will not deflect or bend during use. In other instances, the cleaning wand  114  may be more rigid than the flexible hose  124 , but still somewhat resiliently flexible so that it can bend during use. 
     Optionally, the upstream end of the cleaning wand  114  can be connected to other auxiliary or accessory cleaning tools, for example an air turbine powered brush  116 . In some instances, the cleaning wand  114  may not be required and the flexible hose  124  may be directly connected to the brush  116  or other accessory or auxiliary tool. Some auxiliary cleaning tools, for example the brush  116  may also be described as second surface cleaning heads or auxiliary cleaning heads. In some instances, the nozzle  412  (described in detail below) of the hand vacuum cleaner  400  may also be described as a second surface cleaning head, particularly when the hand vacuum cleaner  400  is configured as a hand vacuum. Optionally, the cleaning wand  114  or any other second surface cleaning head or auxiliary tool may be connected directly to the nozzle  412 . 
     In accordance with a third aspect, which may be used by itself or with one or more of the other aspects, the removable cleaning unit is secured in position by gravity. This may be achieved using a mount  220  that removably receives attachment member  120 . This aspect is preferably used with the second aspect but may be used with the first aspect and/or the second aspect. 
     Some examples of the mount  220  may be configured to removably receive a portion of the hand vacuum cleaner  400  or preferably, as exemplified, an attachment member  120  that may be removably coupled to the hand vacuum cleaner  400 . Alternately, the attachment member may itself include the mount so that the attachment member may be removably attached directly to the lower portion  216 . This may be achieved by the attachment member and the mount being an integrated assembly wherein the attachment member and the mount are not disconnectable from each other (i.e. the hand vacuum cleaner  400  can be removed but not with the attachment member) or the attachment member and the mount may be separable as exemplified in  FIGS. 22-33 , whereby the hand vacuum cleaner may be removed with or without the attachment member so as to increase the versatility of the surface cleaning apparatus. 
     The mount  220 , as exemplified in  FIGS. 1-5 and 15-19 , is preferably configured to retain the hand vacuum cleaner  400  therein under the influence of gravity. Accordingly, a mechanical lock need not be used. In particular, a user may lift the portable surface cleaning apparatus off of upright section  210  without having to press a button or otherwise release a mechanical lock. The absence of mechanical fasteners allows for simple, one-handed removal of the attachment member  120  and the hand vacuum cleaner  400  from the mount  220 , without the need to unlock or undo any fasteners. One-handed detachment of the hand vacuum cleaner  400  may be advantageous as it allows a user to control and maneuver the support structure  210  with one hand while simultaneously removing the hand vacuum cleaner  400  from the mount  220  with the other hand. In use, this may allow a user to frequently attach and detach the hand vacuum cleaner  400  from the mount  220  in response to the user&#39;s needs, for example navigating around furniture, stairs or other obstacles on the surface to be cleaned. 
     Optionally, the mount  220  may be outfitted with magnets for retaining the attachment member  120 . Magnets may assist in holding the hand vacuum cleaner on the mount and still permit one-handed removal as no fastener or lock need be manually released. 
     Alternatively, or in addition, as exemplified in  FIGS. 22-33  a lock, for example a rotatable locking knob may be used to releasably secure adjustment member  120  and mount  220  together. In such an embodiment, it is preferred, as exemplified in the embodiment of  FIGS. 22-33 , that when the lock is disengaged, hand vacuum cleaner  400  is still held in position by gravity. Other examples of possible fasteners include clips, snaps, and straps. Magnets may alternately or in addition be used. 
     One example of a mount  220 , as exemplified in  FIGS. 1-5 , is a generally U-shaped member sized to receive a contact member on the attachment member  120 , for example collar  140  or other mounting portion of the complimentary attachment member  120 . The inner surface of the mount  220  comprises a corresponding contact member, for example protrusion  222  that extends outward from the inner surface of the mount  220  and removably seats within the generally U-shaped channel  144  of the collar  140 . 
     In this example, loads placed on the mount  220  (via both the U-shaped opening and/or the mount bracket  224 ) are in turn transferred via the lower portion  216  of the handle  210  to the surface cleaning head  300  and ultimately to the floor or other type of surface being cleaned. Another portion of the load of the hand vacuum cleaner  400  may be supported by an additional mounting bracket, such as mount bracket  224 , which receives and supports optional rear wheel  480  of the hand vacuum cleaner  400 . The surface of the mount bracket  224  may be complimentary to the curved shape of the optional rear wheel  480  so that the optional rear wheel  480  can at least partially nest within mount bracket  224 . An upward facing protrusion  222  on the inner surface of the mount  220  seats within the channel  144  of the attachment member  120  and provides a degree of lateral support, restraining the movement of the attachment member  120  (and therefore the hand vacuum cleaner  400 ) when the handle  210  is moved from a vertical position to an angled position when in use. Further, protrusion  222  may comprise a cam surface to assist in guiding protrusion  222  into channel  144  as the portable surface cleaning apparatus is lowered onto mount  220 . In this example the attachment member  120  and the optional rear wheel  480  are preferably not held in place by clips, straps or any other type of mechanical fastening means. 
     Optionally, the protrusion  222  may not have a uniform cross-section along its length. As exemplified in  FIG. 4 , the upward facing portions of the protrusion  222  (both ends of the continuous protrusion shown in  FIG. 4 , or the upward facing portions of each saddle flange  280  described below) may taper or converge such that the upward facing portions of the protrusion  222  are narrower than the connecting central portion. When the attachment member  120  is lowered into the mount  220  by the user, the tapered upward facing portions of the protrusion  222  are generally the first portion of the protrusion  222  to engage the collar  140 . To adequately secure the attachment member  120  within the mount  220 , the width or thickness of the central portion of the protrusion  222  is preferably substantially the same as the width of the channel  144  of the collar  140 , leaving only a small clearance, if any, between the channel  144  walls and the protrusion  222 . It will be appreciated that if the clearance is too tight, it may be difficult to quickly place the attachment member  120  onto the mount  220 . 
     One advantage of the tapered upwards facing portions of the protrusion  222  may be that because the upwards facing portions have a reduced width (relative to the channel  144  width) it may be easier for a user to place the channel  144  over the ends of the upwards facing portions due to the increased clearance between the channel  144  walls and the edges of the tapered upwards facing portions. After the upward facing portions have been received in the channel  144  they may act as a cam and contact the channel  144  walls or other surfaces of the collar  140  (which may function as follower or camming surfaces) and align or register the attachment member  120  within the mount  220 . The cam-like action of the protrusion  222  may create a self-aligning or self-registering connection between the attachment member  120  and the mount  220 . 
     As exemplified, in addition to supporting the weight of the hand vacuum cleaner  400 , the attachment member  120  also preferably serves as a fluid conduit establishing a fluid flow connection between the hand vacuum cleaner  400  and the airflow conduit  110 , which is preferably a flexible hose  124 . The mount  220  may be made from any material that can support the weight of the hand vacuum cleaner  400 , including plastic and metal. 
     A second example of a mount  220 , as exemplified in  FIGS. 15-19  comprises more than one member configured to receive the collar portion  140  of attachment member  120 . As exemplified, two support rods or ribs  256  are provided, each or which holds part of mount  220 . 
     Split saddle mount  220  comprises a pair of generally opposing saddle flanges  280  (one on each rib and each having a contact surface) that cooperate to provide a mount or a mounting location for the attachment member  120  that is connected to the hand vacuum cleaner  400 . Due to the spacing of the ribs  256  and the general curvature of the hand vacuum cleaner  400 , the hand vacuum cleaner  400  is preferably positioned in front of ribs  256 . The attachment member  120  may extend rearward of hand vacuum cleaner  400  and may be received on split saddle flanges  280 . Alternately, it will be appreciated that hand vacuum cleaner  400  may be partially nest between, or be received between, the ribs  256 . 
     As exemplified, to supportingly engage the attachment member  120 , each saddle flange  280  preferably includes a contact member, for example a projection or protrusion (see  FIG. 18 ) that is received within the channel  144  of the collar  140  (as described in more detail with reference to  FIGS. 11-14  below). The generally curved profile of the collar  140  and channel  144  may enable the attachment member  120  (and the associated hand vacuum cleaner  400 ) to generally self-level or self-register between the ribs  256  when the user initially places the attachment member  120  on the saddle flanges  280 . Optionally, the saddle flanges  280  may include magnets or other fastening devices to secure or retain the attachment member  120 . 
     Ribs  256  are secured in position by a connecting structure at the upper and lower end of ribs  256 . Any such structure may be used. As exemplified in  FIGS. 15-19 , second portion  216  may comprise a generally upside down U-shaped wishbone portion  250  to secure the upper ends of ribs  256  together. 
     If used together with the first aspect, the wishbone  250  may be provided with a hinge  218  at the centre of an upper portion of the wishbone  250 , and each prong  254  of the wishbone extends downward, and connects to a rib  256 . The ribs  256  are preferably substantially parallel and cooperate to define a split saddle mount  220  for receiving the attachment member  120  and the hand vacuum cleaner  400 . Optionally, the ribs  256  may be integrally formed with the prongs  254  of the wishbone portion  250 , or they may be separate tubes or rods fastened to the prongs  254  of the wishbone  250 , as shown. 
     The lower ends of the ribs  256  may be attached to a bracket  260  having a generally opposite configuration than the wishbone. That is, the bracket may include two, upward facing projections  262 , for attaching to the ribs  256 , that are connected by a cross-member  264  to provide a single downward facing coupling point  266 . An advantage of providing a single, downward facing coupling point may be the fact that a single coupling point can be pivotally and rotationally connected to the surface cleaning head  300 . Another advantage is that a narrower rear end may be utilized for the surface cleaning head  300 . 
     The bracket  260  also includes a housing  268 , which is preferably hollow, having a lower opening  270  that is connected in flow communication with the surface cleaning head  300  (e.g. by a rigid pipe as exemplified by  FIGS. 21-30  or, by a flexible hose as exemplified in  FIGS. 15-19 ). Housing  268  may be pivotally mounted to surface cleaning head, preferably at about the location of rear wheels  320 , such as by having a portion pivotally mounted to the axle of rear wheels  320 . Optionally, the connection between the lower opening  270  and the surface cleaning head  300  can be a rotatable and pivotal connection. The hollow housing  268  may extend from the lower opening  270 , through the cross-member  264  to define an upper collar  272 . 
     A third example of a mount  220  and complimentary attachment member  120  is exemplified in  FIGS. 20-21 and 22-33 , specifically  FIGS. 27-33 . This example of the attachment member  120  exemplifies an attachment member  120  that is optionally lockably attachable to mount  220 . 
     Mount  220  optionally comprises a contact member, for example structural member  186  that has a central opening for receiving the lower portion  216  of the support structure  210 . Mount  220  may be secured to lower portion  216  such as by a key, a set screw, an adhesive or other locking means. In the example illustrated the central opening of structural member  186  is generally annular (to receive the generally cylindrical lower portion  216 ), while in other examples the central opening may have a different shape that is complimentary to the profile of its respective lower portion. In other examples, the mount  220  or the structural member  186  may be integrally formed with the lower portion  216 . 
     The mount  220  also comprises a pair of upwardly extending contact members, for example bosses  182  (not shown in  FIGS. 20-21 ). The bosses  182  may be integral with structural member  186  and are sized and shaped to be received within corresponding holes  184  in shell  174  of the attachment member  120 . Once received within their corresponding holes  184 , the bosses  182  serve to register the shell  174  on the mount  220  and restrain movement of the shell  174  relative to the mount  220  in the horizontal plane (when viewed with vacuum cleaner  100  in its upright position). 
     Preferably, as in the example shown, each boss  182  is generally conical, or frusto-conical, in shape so that a proximate end of each boss  182  (adjacent the mount  220 ) is wider (i.e. has a larger diameter) than the distal end of each boss  182  (spaced apart from the proximate end). Generally, the holes  184  in the shell  174  have a width (or diameter) that corresponds to the widest portion of the bosses  182 , for example the base or proximate portion of the bosses  182  in the current example. Having a width (or diameter) of a hole that corresponds to the widest portion of each boss  182  enables the entire boss  182  to be received within its corresponding hole  184 . Providing a narrower distal end or tip on each boss  182  may make it easier for a user to position the bosses  182  within their holes  184  when placing the shell  174  onto the mount  220  and may enable the surface of each boss  182  to act as a guide or cam engaging a corresponding guiding or cam surface on the shell (for example the inner surface of the holes  184 ) for guiding the shell  174  to its desired mounted position. In other examples, the mount  220  may contain a greater or fewer number of bosses  182  and each boss  182  may have any desired shape (typically corresponding to the shape of the corresponding holes  184 ), including cubic, rectangular prism and pyramidal. 
     In some examples the mount  220  also includes a coupling, locking or attachment means for securing the shell  174  to the mount  220 , when the shell  174  is seated on the mount  220  (with bosses  182  received within corresponding holes  184 ). As exemplified in  FIGS. 24-30 , one example of an attachment means is locking knob  188  that is rotatably connected to the mount  220 , such as on protrusion  190 , and is secured thereto such as by a screw (not shown). The front, or outer face of the locking knob  188  comprises a pair of tabs  191  that are sized to be graspable by a user to rotate the locking know  188  about the protrusion  190 . The rear, or inner face, of the locking knob  188  comprises a channel or groove  189  that is sized to receive the locking peg  180 . Operation of the locking knob  188  is described below in relation to  FIGS. 28-30 . In other examples, the attachment means may be any suitable mechanism, including clips, snaps, magnets, latches or hook and loop type fasteners. Alternatively, the mount  220  could be free from attachment means and the shell  174  could be held in place by gravity when in use. 
     As exemplified in  FIGS. 24-30 , the groove  178  is a semi-cylindrical recess formed in shell portion  175   a  that is shaped to at least partially receive the lower portion  216  of the support structure  210 . In other examples, the shape of the groove  178  may be any suitable, complimentary shape chosen to fit the lower portion of the support structure  210 . In the example illustrated, the groove  178  subtends approximately 180 degrees of arc, while in other examples the groove  178  may subtend a larger or smaller arc, for example 200 degrees or 30 degrees. Having the lower portion  216  at least partially received within or nested within the groove  178  may increase the stability of the shell  174  when placed on the mount  220 , which may reduce the lateral shear loading on bosses  182 . 
     Shell  174  also comprises a protrusion or locking peg  180 , extending from shell  174 . In the example illustrated, the locking peg  180  is located on shell portion  175   a . In other examples, the locking peg  180  may be located on any suitable portion of the shell  174  and may have any shape or profile that is complimentary to the groove  189  on the rear face of the locking knob  188 . 
       FIG. 31  is an illustration of the attachment member  120  when the shell  174 , supporting the hand vacuum cleaner  400 , is slightly separated from the mount  220 , for example when the shell  174  is in the process of being placed on, or removed from, the mount  220 . As shown in this figure, the lower portion  216  is partially received within the groove  178  which may serve to stabilize the shell  174  and may also serve as a locating or positioning means, which may help a user to horizontally align the holes  184  in the shell  174  with the bosses  182  on the mount  220 . When the shell  174  is spaced apart from the mount  220  the knob  188  is rotated to its open or unlocked position, as shown. 
     When the shell  174  is lowered onto the mount  220 , as shown in  FIG. 28 , the shell  174  (and hand vacuum cleaner  400 ) are supported by an upper face of the mount  220  and the bosses  182 . The locking knob  188  is rotated to the unlocked position. 
     As shown in  FIG. 33 , to secure the shell  174  to the mount  220 , the knob  188  is rotated into its closed or locked position (clockwise as illustrated in  FIGS. 28-30 ), thereby retaining locking peg  180  and restraining vertical movement of the shell  174  relative to the mount  220 . As described above, horizontal movement (i.e. in the horizontal plane) of the shell  174  relative to the mount  220  is restrained by the combination of the groove  178  and the bosses  182  received in holes  184 . Accordingly, with the knob  188  in the locked position (as shown in  FIG. 30 ) the shell  174  is fixed relative to the mount  220 . 
     Optionally, as exemplified in  FIGS. 20-21 , the mount  220  may be configured to operated only as a gravity mount (free from fasteners) and may not include a locking knob  188  or locking peg  180 . 
     In operation, the cleaning unit may not be lifted vertically off of attachment member  120  if the lock is engaged. If the lock is not engaged, then the attachment member may be lifted off of the mount  220  and the cleaning unit removed while still in air flow communication with hose  124 . 
     In each example of the surface cleaning apparatus  100 , the mount  220  may be located in a variety of locations along the length of the second portion  216 . Preferably, the mount  220  is positioned at approximately the waist height of the intended user (e.g., 2.5-3.5 feet above the floor) so that the user can attached or detach the hand vacuum cleaner  400  from the support structure  210  without bending over. This may decrease the stress and strain experienced by the user when the user removes the hand vacuum cleaner  400  from the support structure  210 . 
     In other examples, the mount may be any type of supporting apparatus, connected to the support structure of the surface cleaning apparatus, that is configured to detachably support the cleaning unit, for example the hand vacuum cleaner  400  that includes both the dirt collection chamber and the suction motor. Preferably, as described above, the mount is configured to stably support the cleaning unit and retain the cleaning unit in the mounted position in the absence of a locking mechanism or when a locking mechanism is in the unlocked position. This configuration can provide both stability and quick, easy access for a user wishing to remove the cleaning unit. 
     For example, as exemplified in  FIGS. 34 and 35 , a pod or hand carriable cleaning unit  400  may have a motor housing  500  having a mount  502 . Mount  502  has an opening  504  that is slideably mounted on to tube  506 . As exemplified, tube  506  is a part of air flow conduit  110  and is provided on cleaning head  300  and, preferably rotatably mounted thereon. When mount  502  is slid downwardly on to tube  506 , pod  400  is positioned on cleaning head  300  and will remain in place until lifted off. It will be appreciated that a similar mounting means may be used to mount pod higher up on a support shaft provided on or in lieu of tube  506 . In an alternate embodiment, a lock may be provided to secure pod  400  in place. 
     In some examples, the mount can include a supporting platform that is connected to, and extends from the support structure. The supporting platform can be sized and shaped to correspond to the lower end of the cleaning unit, for example the rear portion  410  of the hand vacuum  400 . In this example the supporting platform is substantially co-extensive with the bottom of the suction motor housing, thereby underlying the centre of gravity of the cleaning unit, which enables the cleaning unit to remain seated on the supporting platform, even in the absence of a locking member. The supporting platform can be a solid plate or, can be provided with a plurality of apertures or openings to allow the air to flow through the platform (for example to accommodate cleaning unit exhaust air flow or provide a cooling air flow). 
     Optionally, the supporting platform can include a recess or cavity for receiving a least a portion of the cleaning unit, which can allow the supporting platform to positively engage or retain the cleaning unit thereby inhibiting the cleaning unit from tipping over or falling off the platform when the surface cleaning apparatus is in use. 
     Optionally, the supporting platform can be pivotally mounted to the support structure, and biased toward the support structure, so that the support platform will automatically fold toward the support structure when the cleaning unit is removed. In such a configuration, the distance by which the support structure protrudes from the front of the support structure may be reduced, which can preserve the advantage of the floor cleaning head being able to be maneuvered beneath furniture and into other narrow spaces, as described above. 
     In another example, the mount may be a lip or ledge that is substantially smaller than the bottom surface of the cleaning unit, for example having an area that is less than 50% of the area of the bottom of the cleaning unit. In this example, the cleaning unit may not consistently balance when resting on the ledge, depending on the orientation of the support structure. To ensure the cleaning unit remains stable on the ledge in the absence of a latching or locking member, the ledge may include a protrusion, or more than one protrusion, that is slidably received within a corresponding slot or aperture on the cleaning unit. 
     The protrusions can be generally elongated members extending from the ledge. The protrusions can be generally thin or plate like in nature or can be formed as thicker, three dimensional members, including, for example, cylinders and polygonal prisms. In some examples, a user may wish to remove the cleaning unit from the mount by lifting the cleaning unit in a generally upward or vertical direction. In these examples, the protrusions and corresponding slots in the cleaning unit may be oriented in a generally vertical direction. In other examples, the protrusions can extend from the ledge at an angle. In further examples, the protrusions can extend in the generally horizontal direction and the cleaning unit can include a generally horizontal slot. In such examples, a user can mount and remove the cleaning unit by translating the cleaning unit horizontally relative to the support structure. 
     The protrusions can be formed from any suitable material having the necessary mechanical properties to support the weight of the cleaning unit. Potentially suitable materials include plastic and metal. Alternatively, or in addition, the protrusions may be formed to have a cross-sectional shape that contributes to the structural stiffness or rigidity of the protrusion, including, for example C-channel, I-beam, and tubular cross-sectional shapes. 
     Protrusions extending from the ledge can include a single protrusion configured to support cleaning unit, or a plurality of protrusions, arranged in a pattern, that cooperate to support the weight of the cleaning unit and to resist bending and torsion loads exerted by the cleaning unit when the surface cleaning unit is in a stored position or an in use position. 
     The surface cleaning head  300  serves as a base portion of the vacuum cleaner  100  and is preferably in rolling contact with the surface to be cleaned. When the vacuum cleaner is  100  in an upright position (as exemplified in  FIGS. 1, 2, 4, 5, 15, 16 and 20-23 ) the surface cleaning head  300  is supported by optional main or rear wheels  320  and/or optional front wheels (not shown). Any surface cleaning head may be used. 
     In some examples, as exemplified in  FIG. 3 a   , the vacuum cleaner  100  may comprise an additional support wheel  321  that is provided on the support structure  210  to provide additional rolling support when the vacuum cleaner  100  is moved into an angled position during use. In other examples, the surface cleaning head  300  may include a greater or fewer number of wheels. Preferably, lower portion  216  is rotatably mounted to the cleaning head. Accordingly, a user may rotate grip  212  clockwise or counterclockwise to assist in steering the cleaning head. 
     The surface cleaning head  300  also comprises a dirty air inlet  310  that is connected in fluid communication with a dirty air outlet  312  by one or more dirty air conduits (not shown). Preferably, the dirty air inlet is an air flow chamber wherein at least a portion of the lower side is open. 
     The dirty air outlet  312  may be coupled, optionally removably coupled, to the upstream end of the conduit, preferably via a flexible hose  124 , that extends from the dirty air outlet  312  of the surface cleaning head  300  to the upright section, such as the attachment member air inlet  126 . The fluid pathway may continue through the attachment member passageway  129 , which terminates in attachment member air outlet  127 , and through attachment member air outlet  127  which mates with the opening  438  of the portable cleaning apparatus  400 . 
     In some examples, as exemplified in  FIGS. 15-19 , the surface cleaning head  300  includes a hollow conduit member  330  and a second air conduit  334 . As exemplified in  FIGS. 17-19 , one example of the second air conduit  334  is a second flexible hose  335 . In the preferred arrangement shown, the dirty air outlet  312  of the surface cleaning head  300  is connected to the second or upstream flexible hose  335  and the second flexible hose  335  extends from the dirty air outlet  312 , through the hollow conduit member  330 , through the hollow housing  268  to the upper collar  272 . The downstream end of the second flexible hose  335  may be fixedly connected to the upper collar  272 , or it may have a fitting that seats upon a surface of the upper collar  272  preventing the second flexible hose  335  from retracting within the hollow housing  268  while leaving the downstream end of the second flexible hose  335  free to extend upward, away from the upper collar  272 . 
     The second flexible hose  335  forms part of the continuous airflow passageway that connects the dirty air outlet  312  of the surface cleaning head  300  to the opening  438  on the hand vacuum cleaner  400 . In accordance with a fourth aspect that may be used by itself or with any other aspect, to establish the continuous airflow passageway, the downstream end of the second upstream flexible hose  335  may be connected to the upstream end of the downstream flexible hose  124 . The connection between the flexible hose  124  and the downstream end of the second flexible hose  335  is preferably a detachable connection so that the flexible hose  124  can be detached from the surface cleaning head  300  as described above. 
     Optionally, in a fifth aspect, which may be used by itself or with any one or more other aspects, the second flexible hose  335  is also an extensible, or stretchable, hose that can extend when pulled on by the user. In some examples, the second flexible hose  335  is a stretch hose and may have a stretched length to non-stretched length ratio of between 2:1-6:1. In examples where the second flexible hose  335  is not stretchable, when a user removes the hand vacuum cleaner  400  from its mount during use, the maximum distance that the hand vacuum cleaner  400  can be separated from the support structure  210  and the surface cleaning head  300  is determined by the length of the flexible hose  124 . However, in some instances, a user may wish to move the hand vacuum cleaner  400  a greater distance from the support structure  210 , for example to pass the surface cleaning head  300  under a bed or other large piece of furniture. When a stretchable second flexible hose  335  is used, the downstream end of the second flexible hose  335  can unseat from the upper collar  272  and extend away from the bracket  260 , whereby some of hose  335  may pass through housing  268  thereby lengthening the airflow conduit connecting the hand vacuum cleaner  400  to the surface cleaning head  300  and allowing the hand vacuum cleaner  400  to be moved further from the support structure  210  in use. Accordingly, it will be appreciated that some or all of the conduit that may be extended to provide additional length for an air flow passage may be stored on the surface cleaning head  300 . 
     It will be appreciated that lower section  216  may be rotatably mounted on cleaning head  300  without hose  335  extending through a housing  268 . Further, a housing  268  may be used even if lower section  216  is not rotatably mounted to cleaning head  300 . Such a housing need not be pivotally mounted to surface cleaning head. 
     Preferably, the second flexible hose  335  is also resilient so that it will return to its original, un-stretched length when it is released by the user. The resilience of the second flexible hose  335  may tend to retract the second flexible hose  335  through the hollow housing  268  and the hollow conduit member  330  and may serve to re-seat the downstream end of the second flexible hose  335  on the upper collar  272 . In this example, the second flexible hose  335  functions as a variable length air conduit and may reduce the need for a user to add extra hoses or conduit members to the vacuum  100  during use. 
     To allow for easy and repeated extension of the second flexible hose  335 , the second flexible hose  335  may be sized to freely pass through both the hollow conduit member  330  of the surface cleaning head  300  and the hollow housing  268  of the bracket  260 . 
     In the example shown in  FIG. 15-19 , the hollow housing  268  is integral the bracket  260  and also serves as the coupling means that connects the lower portion  216  to the surface cleaning head  300 . As shown, the coupling between the lower portion  216  and the surface cleaning head  300  may be the telescoping or overlapping engagement of the lower opening  270  over the surface cleaning head  300  hollow conduit member  330 . In other examples, the coupling or attachment between the lower portion  216  and the surface cleaning head  300  may be any type of connection including a threaded connection, clamps or tabs. The connection between the lower portion  216  and the surface cleaning head  300  may be fixed or selectively releasable. An advantage of providing a single, downward facing coupling point  266  may be the fact that a single coupling point  266  can be pivotally and rotationally connected to the surface cleaning head  300 . Further, the hollow conduit member  330  may be pivotally connected to the surface cleaning head  300 , as exemplified in  FIGS. 15-19 , and in other examples, the hollow conduit member  330  may be fixedly connected to the surface cleaning head  300 , or integrally formed therewith. 
     As shown, the hollow housing  268  may be integral with the bracket  260  and provide both a hollow passageway and an attachment point. However, in other examples, the hollow housing  268  may be external the bracket  260  and may be formed from a separate conduit. Similarly, the air flow conduit  110  connecting the attachment member  120  to the second flexible hose  335  may be the flexible hose  124  or any other suitable conduit, including flexible conduits, rigid conduits, conduits integral with the handle and conduits external the handle. 
     Optionally, the ribs  256  (or another portion of the second portion  216 ) may be surrounded by a housing or shell. The housing may provide structural strength to the second portion  216  or it may merely provide an improved aesthetic appearance of the vacuum  100 , or both. If a housing is formed around a section of the second portion  216  (or any other section of the handle  210  or support structure  210 ) the mount for supporting the hand vacuum (for example the mount  220  or the saddle flanges  280 ) may be within a recess in the housing. Providing a recess in the housing for receiving the hand vacuum may create a more integrated or seamless visual appearance when the hand vacuum is mounted to the support structure  210 ; it may also improve the rigidity of the support structure  210 . 
     In a sixth aspect, which may be used by itself or with any one or more other aspects when hand vacuum cleaner  400  is mounted to the backbone, the centre of gravity of the backbone and hand vacuum cleaner  400  combined is preferably below a plane P extending from the axle of rear wheel  320  to the upper end of upper portion  214  (as exemplified in  FIG. 17 ), thereby improving maneuverability of surface cleaning head  300 . As exemplified, this may be achieved by wishbone portion  250  extending forwardly to provide a mount for upper portion  214  (i.e. the handle) at a forward point of the backbone and passageway  268  extending rearwardly. It will be appreciated that other constructions, such as those exemplified in  FIGS. 1-5  or  FIGS. 20-30 , may be used to position the centre of gravity behind the plane. For example, as best shown in  FIG. 5 , one example of the lower portion  216  includes an upper end that is connected to the hinge  218  such that the upper portion  214  is drivingly connected to the surface cleaning head  300 . In this construction the lower end includes a step-back or kinked-back portion  215 . The step-back portion  215  enables the mount  220  to be positioned sufficiently behind the rear wheels  320  such that the centre of gravity of the combination of the support structure  210  and the hand vacuum cleaner  400  is below the plane P. As a result of this configuration, the surface cleaning apparatus  100  may be more stable when rotated and maneuvered by the user, especially when upper portion  214  is rotated about hinge  218 . Specifically, locating the centre of gravity of the combination of the hand vacuum cleaner  400  and the support structure  210  below the plane P may tend to reduce the over rotation of the support structure  210  or over-steer of the vacuum  100  in use, and may reduce the strain on a user&#39;s arm and wrist. 
     It will be appreciated that the dual hose construction (i.e. the flexible hose  124  and the second flexible hose  335  of  FIG. 15-19 ) may be used in combination with any example disclosed herein or by itself in a surface cleaning apparatus. Similarly, the positioning of a removably mounted portable surface cleaning apparatus with a low centre of gravity may be used in combination with any example disclosed herein or by itself in a surface cleaning apparatus. 
     Preferably, the cleaning unit is a portable surface cleaning apparatus, and more preferably a hand vacuum cleaner, wherein the portable surface cleaning apparatus optionally has a nozzle having an open sided air flow chamber. It will be appreciated that the cleaning unit may be of any construction and may use any particular air treatment member (e.g., one or more cyclones comprising one or more cyclonic cleaning stages and/or one or more filters). Further, the cleaning unit may alternately, or in addition, selectively receive an auxiliary cleaning tool. 
     Referring now to  FIGS. 6-14 , examples a hand vacuum cleaner  400  and the attachment member  120  of the vacuum  100  are shown in more detail. 
     In some examples, the cleaning unit can be a hand vacuum cleaner  400  that can be operated as the vacuum suction supply for the vacuum  100  and it can be operated as a stand alone hand vacuum cleaner, that is movable along a surface to be cleaned by gripping and maneuvering handle  402 , when it is removed from, or detached from the support structure  210 . The hand vacuum cleaner  400  includes an upper portion  404 , a lower portion  406 , a front  408 , and a rear  410 . In the example shown, maneuvering handle  402  is provided at the upper portion  404 . In alternate examples, maneuvering handle  402  may be provided elsewhere on the vacuum cleaner  400 , for example at the rear  410 . 
     In the example shown, the hand vacuum cleaner  400  comprises a nozzle  412  and a cyclone unit  414 , which together preferably form a cleaning head portion  416  of the hand vacuum cleaner  400 . In the example shown, the cleaning head portion  416  is provided at the front  408  of the hand vacuum cleaner  400 . 
     Nozzle  412  comprises a dirty air inlet  418 , through which dirty air is drawn into the portable cleaning apparatus  400 , and when used as a hand vacuum cleaner the nozzle  412  directly engages a surface to be cleaned. An airflow passage extends from the dirty air inlet  418  to a clean air outlet  420  of the hand vacuum cleaner  400 . In the example shown, clean air outlet  420  is at the rear  410  of the hand vacuum cleaner  400 . It will be appreciated that clean air outlet may optionally be connected to a fluid conduit provided in the floor cleaning unit. 
     Cyclone unit  414  is provided in the airflow passage, downstream of the dirty air inlet  418 . In the example shown, the cyclone unit  414  comprises one cyclone  422 , and one dirt chamber  424 . In alternate examples, the cyclone unit  410  may include more than one cyclone, and more than one dirt chamber. Further, the cyclones may be arranged in stages, and may be provided in parallel or in sequence. Alternately, or in addition, one or more filters or other dirt separation members may be used. 
     In the example shown, the nozzle  412  is positioned at the lower portion  406  of the portable cleaning apparatus  400 . More preferably, as in the example shown, nozzle  412  is positioned at the bottom of the portable cleaning apparatus  400 , and is preferably beneath the cyclone unit  414  when used as a hand vacuum cleaner and is between the cyclone unit  414  and the mount  220  when attached to the support structure  210 . Further, as in the example shown, the nozzle  412  is preferably fixedly positioned at the lower portion  406  of the portable cleaning apparatus  400 . That is, the nozzle  412  is not movable with respect to the remainder of the portable cleaning apparatus  400 , and is fixed at the lower portion  406  of the portable cleaning apparatus  400 . As shown in  FIGS. 7 and 8 , nozzle  412  has a width W N  and, as shown in  FIG. 11 , coupling plate  123  has a width W p  that is generally the same as width W N . 
     Nozzle  412  exemplifies a particular design for an open sided nozzle. Open sided nozzle  412  has an open side that faces the surface to be cleaned when the nozzle is placed against a surface to be cleaned. Accordingly, nozzle  412  defines an air flow chamber that has an open lower side. In operation, air will flow longitudinally through the air flow chamber to an air exit. It will be appreciated that only part of the nozzle may have an open lower side. Alternately, all of the nozzle, from an air inlet end to the air outlet, may have an open lower side. It will be appreciated that various other design may be used. An advantage of using an open sided nozzle is that the nozzle may be the member that is used to mount hand vacuum cleaner  400  to attachment member  120 . 
     Referring now to  FIGS. 8-14 , nozzle  412  comprises an upper nozzle wall  426 . In the example shown, the upper nozzle wall  426  comprises a portion  419  of a wall  415  of the cyclone unit. Nozzle  412  further preferably comprises a depending wall  428  extending downwardly from the upper nozzle wall  426 . The depending wall  428  is generally U-shaped. The height of the depending wall may vary. The open end of the U-shape defines an open side wall  430  of the nozzle  412 , and forms the dirty air inlet  418  of the portable cleaning apparatus  400 . In the example shown, the open side wall  430  is provided at the front of the nozzle  412  and forms a portion of a flow passage that is in communication with the opening  438 . When in use as a hand vacuum, optional wheels  435  are in contact with a surface and the open side wall  430  sits above and is adjacent a hard surface to be cleaned. It will be appreciated that depending wall  428  may be positioned only rearward of opening  438 . Alternately, or in addition, depending wall  428  may be provided adjacent the lateral sides of opening  438 . The depending walls may be discrete walls or they may be joined together as exemplified. The walls may be continuous or discontinuous. 
     In the example shown, the lower end  432  of the depending wall  428  defines an open lower end  434  of the nozzle  412 . The open lower end  434  extends to the front  408  of the hand vacuum cleaner  400 , and merges with the open side  430 . In use, the open lower end  434  faces a surface to be cleaned. In the example shown, a plurality of wheels  435  are mounted to the depending wall  428 , and extend below the lower end  432  of the depending wall  428 . Accordingly, when in use as a hand vacuum, when wheels  435  are in contact with a surface, the lower end  432  of the depending wall  428  is spaced from a surface to be cleaned, and the space between the lower end of the depending wall  428  and the surface to be cleaned form a secondary dirty air inlet to the portable cleaning apparatus  400  when used as a hand vacuum. 
     The upper nozzle wall  426 , depending wall  428 , and open lower end  434  of the nozzle  412  define an airflow chamber  436  of the nozzle. An opening  438  is preferably provided in the upper nozzle wall  426 , and is in communication with the airflow chamber  436 . When in use as a hand vacuum, the wheels  435  are in contact with a surface, the opening  438  faces a surface to be cleaned, air enters the dirty air inlet  418 , passes horizontally through the airflow chamber  436 , and passes into the opening  438 . Opening  438  is in communication with a cyclone inlet passage  439 , which is in communication with a cyclone air inlet  440  of cyclone  422 . In some embodiments, opening  438  need not be in upper wall  426 . 
     Nozzle  412  and attachment member  120  are configured such that attachment member  120  may form part of the air flow conduit to opening  438  when attachment member  120  is mounted to hand vacuum cleaner  400 . For example, when the portable cleaning apparatus  400  is used in combination with the support structure  210  and the surface cleaning head  300 , the opening  438  in the nozzle  412  is in sealed, fluid communication with the air outlet  127  of the attachment member  120 . By way of this connection, a continuous fluid pathway is established between the dirty air input  310  of the surface cleaning head  300  and the opening  438 . 
     It will be appreciated that examples of the attachment member  120  may be removably mounted to nozzle  412  by any engagement means known in the connecting arts. For example, pivoting arms may be used, see for example  FIG. 14 , or sliding engagement may be used, see for example  FIG. 25 . Further, attachment member  120  may be of any configuration. Attachment member  120  may be part of, or may be connected to, an accessory cleaning tool by any means, such as a flexible hose. The flexible hose may be hose  124  if hose  124  is removably mounted to the floor cleaning unit. 
     As exemplified in  FIGS. 1-19 , one example of the attachment member  120  is removably engaged with nozzle  412  by the engagement of pivoting arms in slots provided on nozzle  412 . Accordingly, for example, nozzle  412  may also include a slot  490  defining a recess in the depending wall  428  that is adjacent the upper nozzle wall  426 . The slot  490  preferably extends continuously along the U-shaped portion of the nozzle depending wall  428  and may be bounded at each end by corners  492 . The attachment member  120  includes two arms  150  each having a shoulder  154  and being pivotally connected to the coupling plate  123  using pins  156  (alternatively, the arms  150  could be resilient).  FIG. 14  is a partially exploded view of the attachment member  120 , illustrating one example of the rotational connection between the coupling  142  and the collar  140 . In the example shown, the coupling  142  comprises a cylindrical body wall that passes through an opening in the collar  140 . Once the coupling  142  had been inserted into the collar  140  it is retained using fastening clip  143 . The combination of the coupling plate  123  and the arms  150  may also be described as connecting portion, mounting portion or nozzle mounting portion of the attachment member  120 . 
     In order to assemble the mount on nozzle  412 , coupling plate  123  may be slid into the open end of airflow chamber  436 . Accordingly, when the coupling plate  123  of the attachment member  120  is slid into the airflow chamber  436 , the arms  150  are pressed together by the nozzle  412  walls until the point when arms  150  are aligned with slot  490  (i.e. when the shoulders  154  are advanced past the corners  492 ). When the arms  150  are aligned with the slot  490 , the attachment member  120  is “clicked-in” or locked in place when the arms  150  spread apart and the shoulders  154  of the arms  150  become lodged behind the corners  492  of slot  490 . The arms  150  may be manually separated or the attachment member may include a biasing means (not shown) that biases the arms  150  apart. With the arms  150  in the spread configuration the attachment member  120  cannot be slidingly removed from the nozzle  412 . When a user wishes to detach the attachment means  120  from the nozzle  412  the user may squeeze upstanding tabs  152  together thereby allowing the shoulders  154  to slide past the corners  492 . The mount may alternately be inserted by squeezing upstanding tabs  152  together so that plate  123  may be inserted in chamber  436 . 
     When the hand vacuum cleaner  400  is coupled to the attachment member  120  the airflow chamber  436  may receive, and be partially filled with the coupling plate  123  (as exemplified in  FIG. 1-5, 15-19, 20-21 or 22-33 ) of the attachment member  120 . The coupling plate  123  is preferably shaped to be slidingly received within the airflow chamber  436 . 
     Insertion of the coupling plate  123  into the airflow chamber  436  serves to register the air outlet  127  with the nozzle opening  438 . As shown, the air outlet  127  has a width W o  and a length L o  that are preferably the same as the width W o  and a length L o  of the opening  438 . A sealing gasket  123  may provided at the juncture of the openings. 
     In some examples, as exemplified in  FIG. 21 , the hand vacuum cleaner  400  may be connected to the attachment member  120  using a complimentary tongue and groove connection, instead of or in addition to the arms  150  and slot  490  described above. As exemplified in  FIG. 21 , the nozzle  412  of the may contain a slot or groove  494 . Optionally, the grooves  494  on each side of the nozzle  412  may be separate, or they may be different portions of a single continuous groove  494  (like the continuous slot  490 ). The grooves  494  are sized to receive corresponding tongues  170  extending from a surface of the attachment member  120 . When the tongues  170  are slidingly received within the grooves  494  movement of the portable surface cleaning apparatus  400  is restrained in the sideways and forward-backward directions relative to the backbone  200 . A sealing gasket may optionally be provided. 
     The nesting of the tongues  170  into the grooves  494  can provide sufficient stability and support for the portable surface cleaning apparatus  400  that additional fasteners are not necessary. When the surface cleaning apparatus  100  is in use, the gravitation forces acting on the portable surface cleaning apparatus  400  are sufficient to keep it seated on the attachment member  120 . The grooves  494  may have downward facing open ends that can engage the tongues  170  when the portable surface cleaning apparatus  400  is lowered onto the attachment member by the user in a vertical movement. To detach the portable surface cleaning apparatus  400  from the attachment member  120  the user may lift or slide the portable surface cleaning apparatus  400  upward to a disengaged position where the tongues  170  are removed from the grooves  494 . 
     The attachment member  120  and the nozzle  412  may alternately, or in addition also include a plurality of magnets  158  that magnetically couple the attachment member  120  to the nozzle  412  to improve the connection between them and ensure that air outlet  127  is properly registered with opening  438 . It will be appreciated that, in an alternate embodiment, only magnets maybe used. Other mounting means may be used. For example, a plurality of latches may be used or air outlet  127  may extend into opening  438 . 
     As exemplified in  FIGS. 26-29 , the cleaning unit may be secured in position by sliding engagement. As exemplified, a coupling plate  123  is configured to be slidingly received within a portion of the nozzle of the surface cleaning apparatus, and is sized so that the air outlet  127  is registered with the air inlet of the hand vacuum cleaner  400  when coupled. As exemplified, hand vacuum cleaner  400  may be held on the coupling plate  123  using only gravitational forces once it is slid into position. As with the embodiment of  FIG. 21 , coupling plate  123  may be formed as or with one or more tongues that are received in mating groves of the hand vacuum cleaner  400 . 
     Clean air outlet  420  is provided downstream of the cyclone unit  414 , suction motor and optional post-motor filter contained optionally within the cleaner body  460 . Clean air outlet  420  may comprise a plurality of apertures formed in housing  461 . The cleaner body  460  may also contain one or more of a separation plate, a dirt chamber a pre-motor filter and a plurality of connecting fluid conduits or passageways. 
     In the examples shown, cleaner body  460  is removably mounted to head portion  416 . For example, cleaner body  460  may be entirely removable from head portion  416 , or pivotally mounted to head portion  416 . Accordingly, cleaner body  460  and head portion  416  may be separated in order to provide access to the interior of cleaner body  460  or head portion  416 . This may allow a pre-motor filter to be cleaned, changed, or serviced, or the motor to be cleaned, changed or serviced. Alternately, head portion  416  may be cleaned or serviced. For example, any dirt stuck in the enclosed passages portable cleaning apparatus  400  may be removed. Alternately, a replacement cleaner body  460  or head portion  416  may be provided, and may be mounted to an existing head portion  416  or cleaner body  460 , respectively. 
     One or more additional rear wheels  480  may be mounted to housing  461  at lower portion  406 , and may be used in conjunction with wheels  435  when the portable cleaning apparatus  400  is used as a hand vacuum. When the portable cleaning apparatus  400  is attached to the support structure  210  the additional wheel  480  preferably engages with the mount bracket  224  and partially supports the portable cleaning apparatus  400  on the handle  210  as described above. 
     Preferably, as exemplified in  FIGS. 11 and 28 , in accordance with a seventh aspect that may be used by itself or with one or more other aspects, the portion of the attachment member  120  that is used to mount the attachment member to the backbone may also comprise part of the air flow path from surface cleaning head  300  to hand vacuum cleaner  400 . For example, as exemplified in  FIG. 11 , the attachment member  120  may include a mounting portion or collar  140  that includes a coupling  142  and defines a channel  144 . The collar  140  is connected to the airflow passageway  128 , or alternatively may be connected directly to the air conduit  110 . Optionally, the coupling  142  is a rotatable coupling that allows the airflow passageway  128  to rotate relative to the collar  140 . 
     In another example, as exemplified in  FIG. 29 , the attachment member  120  comprises a shell  174  having two complimentary shell portions  175   a  and  175   c , which cooperate to define the outer surfaces of the shell  174 . Shell portion  175   a  comprises a coupling  176  for joining the attachment member airflow passage way  128  to the shell  174  and a groove  178  for receiving a portion of the lower portion  216 . 
     The coupling  176  may be any type of suitable coupling including a rigid coupling, a fixed coupling, a releasable coupling and a rotatable coupling. The coupling  176  comprises a central opening or aperture that forms part of the continuous airflow conduit or passage way between the air inlet  126  and the air outlet  127  formed in coupling plate  123  (which, in the example illustrated is formed from complimentary portions  123   a ,  123   b  and internal members  177 ). The coupling  176  and the air outlet  127  are connected in fluid communication by internal shell conduit  175   c  (shown comprising two portions, but optionally formed from more than two portions or a single member). Therefore, in the present example, as best illustrated in  FIG. 26 , dirty air from the surface cleaning head  300  travels into air inlet  126 , through airflow passageway  128 , through shell portion  175   a , through internal shell conduit  175   c  and exits via air outlet  127  formed through shell portion  175   b  and the integral coupling plate  123 . In the example shown, airflow passageway  128  is connected to flexible hose  124  using an annular insert  179  that comprises clips  160 . In other examples, the clips  160  may be integral the airflow passageway  128 . 
     The upstream end of the airflow passageway  128  defines the air inlet  126 . In operation, the air inlet  126  is preferably coupled to the airflow conduit  110  that extends to the surface cleaning head  300  (the flexible air hose  124  in the example shown). As exemplified in  FIGS. 10-14 , the air inlet  126  is releasably coupled to the flexible air hose by clips  160 . Downstream of the coupling  142  an enclosed airflow passage connects the airflow passage  128  to the air outlet  127 . It will be appreciated that the attachment member  120  need not comprise part of the air flow passage. For example, coupling  142  may be located out of the flow path defined by passageway  128 . Alternately, plate  123  need not have opening  127 . Accordingly, attachment member may have a first part that is secured to hand vacuum cleaner  400  and a second distinct part that completes that air flow passage from surface cleaning head  300  to opening  438 . 
     The airflow passageway  128  may be flexible or rigid and may be generally straight or may have a curved shape, as shown. Preferably, the curved airflow passageway  128  subtends fewer than 45 degrees. 
     It will be appreciated that the removable cleaning unit or hand vacuum cleaner and the bendable wand may be used by themselves or with any other feature disclosed herein. In addition, any of the features disclosed herein may be used by themselves, or with any other feature, and may include the removable cleaning unit and the bendable wand. It will be appreciated that the removable cleaning unit may comprise the operating components of the surface cleaning apparatus (the motor and cyclones/filters) or only some of them and is preferably capable of being used as a self contained portable cleaning apparatus if removed from physical contact with and air flow communication with the upright vacuum cleaner. 
     It will be appreciated that the gravity mount construction may be used by itself or with any other feature disclosed herein. 
     It will be further appreciated that any construction of an upright structure for a surface cleaning apparatus may be used by itself or with any other feature disclosed herein. 
     In addition, any of the features disclosed herein may be used by themselves, or with any other feature. 
     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.