Patent Publication Number: US-2021169287-A1

Title: Agitator with debrider and hair removal

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/469,853, filed Mar. 10, 2017, which his fully incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     This specification relates to surface cleaning apparatuses, and more particularly, to agitators for reducing and/or preventing hair from becoming entangled and systems/methods for removing collected hair without the user having to contact the hair. 
     BACKGROUND INFORMATION 
     The following is not an admission that anything discussed below is part of the prior art or part of the common general knowledge of a person skilled in the art. 
     A surface cleaning apparatus may be used to clean a variety of surfaces. Some surface cleaning apparatuses include a rotating agitator (e.g., brush roll). One example of a surface cleaning apparatus includes a vacuum cleaner which may include a rotating agitator as well as vacuum source. Non-limiting examples of vacuum cleaners include robotic vacuums, upright vacuum cleaners, canister vacuum cleaners, stick vacuum cleaners, and central vacuum systems. Another type of surface cleaning apparatus includes powered broom which includes a rotating agitator (e.g., brush roll) that collects debris, but does not include a vacuum source. 
     While the known surface cleaning apparatuses are generally effective at collecting debris, some debris (such as hair) may become entangled in the agitator. The entangled hair may reduce the efficiency of the agitator, and may cause damage to the motor and/or gear train that rotates the agitator. Moreover, it may be difficult to remove the hair from the agitator because the hair is entangled in the bristles. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features advantages will be better understood by reading the following detailed description, taken together with the drawings wherein: 
         FIG. 1  is a bottom view of one embodiment of a surface cleaning apparatus, consistent with the present disclosure; 
         FIG. 2  is a cross-sectional view of the surface cleaning apparatus of  FIG. 1  taken along line II-II; 
         FIG. 3  is another bottom view of one embodiment of the surface cleaning apparatus of  FIG. 1 ; 
         FIG. 4  is a perspective view of one embodiment of an agitator and debrider consistent with the surface cleaning apparatus of  FIG. 1 ; 
         FIG. 5  is close up of region V in  FIG. 2 ; 
         FIG. 6  is a cross-sectional view illustrating one embodiment of the angle LEA of the engagement portion of a leading edge of a finger; 
         FIG. 7  is a cross-sectional view illustrating another embodiment of the angle LEA of the engagement portion of a leading edge of a finger; 
         FIG. 8  is a cross-sectional view illustrating yet another embodiment of the angle LEA of the engagement portion of a leading edge of a finger; 
         FIG. 9  is a cross-sectional view illustrating a further embodiment of the angle LEA of the engagement portion of a leading edge of a finger; 
         FIG. 10  is a perspective view of one embodiment of a debris collection chamber and debrider; 
         FIG. 11  is a perspective view of another embodiment of a debris collection chamber, debrider, and a lid in a closed position; 
         FIG. 12  is a perspective view of the debris collection chamber, debrider, debrider cleaner, and a lid of  FIG. 11  in an open position; 
         FIG. 13  is another perspective view of the debris collection chamber, debrider, debrider cleaner, and a lid of  FIG. 11  in a partially open position; 
         FIG. 14  is a perspective view of a further embodiment of a debris collection chamber, debrider, debrider cleaner, and a lid in a closed position; 
         FIG. 15  is a perspective view of the debris collection chamber, debrider, debrider cleaner, and a lid of  FIG. 14  in a partially open position; 
         FIG. 16  is a close up of a cross-sectional view generally illustrating one embodiment of a debrider cleaner and debrider having a trailing edge with an arcuate profile; 
         FIG. 17  is another cross-sectional view of the debrider cleaner and debrider of  FIG. 16  having a trailing edge with an arcuate profile 
         FIG. 18  is a perspective view of another embodiment of a surface cleaning apparatus; 
         FIG. 19  is a perspective view of another embodiment of an agitator and a debrider; 
         FIG. 20  is a perspective view of one embodiment of a debrider having a tapered tooth profile; 
         FIG. 21  is a perspective view of a further embodiment of a debrider having a tapered tooth profile; 
         FIG. 22  is a perspective view of another embodiment of a debrider having a tapered tooth profile; 
         FIG. 23  is a close up of region E in  FIG. 22 ; and 
         FIG. 24  is a perspective view of an end of another embodiment of an agitator having a sidewall with an increased thickness. 
     
    
    
     The drawings included herewith are for illustrating various examples of articles, methods, and apparatuses of the teaching of the present specification and are not intended to limit the scope of what is taught in any way. 
     DETAILED DESCRIPTION 
     Various apparatuses or processes will be described below to provide an example of an embodiment of each claimed invention. No embodiment described below limits any claimed invention and any claimed invention may cover processes or apparatuses that differ from those described below. The claimed inventions are not limited to apparatuses or processes having all of the features of any one apparatus or process described below or to features common to multiple or all of the apparatuses described below. It is possible that an apparatus or process described below is not an embodiment of any claimed invention. Any invention disclosed in an apparatus or process described below that is not claimed in this document may be the subject matter of another protective instrument, for example, a continuing patent application, and the applicants, inventors or owners do not intend to abandon, disclaim or dedicate to the public any such invention by its disclosure in this document. 
       FIG. 1  illustrates a bottom perspective view of one embodiment of a surface cleaning apparatus such as a robot cleaning apparatus  10 . The robot cleaning apparatus  10  may include a body or housing  12 , one or more drive devices  14  (such as, but not limited to, one or more wheels and/or tracks driven by one or more electric motors and/or gears), and one or more cleaning devices  16 . While not shown for clarity, the robot cleaning apparatus  10  may also include one or more controllers, motors, sensors, and/or power sources (e.g., but not limited to, one or more batteries) disposed within and/or coupled to the body  12 . As is well understood, the controllers, motors, sensors (and the like) may be used to autonomously navigate the robot cleaning apparatus  10  in a space such that the cleaning devices  16  picks-up (e.g., sweeps up) and collects debris (for example, optionally using suction airflow). 
     Turning now to  FIG. 2 , a cross-sectional view of the robot cleaning apparatus  10  taken along lines II-II of  FIG. 1  is generally illustrated. In the illustrated embodiment, the forward direction of travel of the robot cleaning apparatus  10  is generally illustrated by arrow F. The cleaning device  16  may include one or more agitators  18  that are rotatably driven at least partially within one or more agitator chambers  20  disposed within/defined by the body  12 . The agitator chambers  20  include one or more openings  22  defined within and/or by a portion of the bottom surface/plate  24  of the body  12 . The agitator  18  is configured to be coupled to the body  12  (either permanently or removably coupled thereto) and is configured to be rotated about a pivot axis PA (e.g., in the direction and/or reverse direction of arrow R) within the agitator chambers  20  by one or more rotation systems  26 . The rotation systems  26  may be at least partially disposed in the vacuum body  12 , and may one or more motors  28  (either AC and/or DC motors) coupled to one or more belts and/or gear trains (not shown) for rotating the agitators  18 . 
     When rotated, the agitator  18  is configured pickup and/or sweep debris into one or more debris collection chambers  30  (e.g., dust bins), e.g., as generally illustrated by arrow D. The debris collection chambers  30  may be either permanently or removably coupled to the body  12 , and are configured to be in fluid communication with the agitator chamber  20  such that debris collected by the rotating agitator  18  may be stored. Optionally, the agitator chamber  20  and debris chamber  30  are fluidly coupled to a vacuum source  32  (e.g., a vacuum pump or the like) for generating a partial vacuum in the agitator chamber  20  and debris collection chamber  30  and to suck up debris proximate to the agitator chamber  22  and/or agitator  18 . As may be appreciated, the rotation of the agitator  18  may aid in agitating/loosening debris from the cleaning surface. Optionally, one or more filters  34  may be provided to remove any debris (e.g., dust particles or the like) entrained in the partial vacuum air flow. The debris chamber  30 , vacuum source  32 , and/or filters  34  may be at least partially located in the body  12 . Additionally, one or more tubes, ducts, or the like  36  may be provided to fluidly couple the debris chamber  30 , vacuum source  32 , and/or filters  34 . 
     With reference to  FIG. 3 , the agitator  18  may includes an elongated agitator body  44  that is configured to extend along and rotate about a longitudinal/pivot axis PA. The agitator  18  (e.g., but not limited to, one or more of the ends of the agitator  18 ) is permanently or removably coupled to the body  12  and may be rotated about the pivot axis PA by the rotation system  26 . The agitator  18  may come into contact with elongated debris such as, but not limited to, hair, string, fibers, and the like (hereinafter collectively referred to as hair for ease of explanation). The hair may have a length that is much longer than the circumference of the agitator  18 . By way of a non-limiting example, the hair may have a length that is 2-10 times longer than the circumference of the agitator  18 . Because of the rotation of the agitator  18  as well as the length and flexibility of the hair, the hair will tend to wrap around the circumference of the agitator  18 . 
     As may be appreciated, an excessive amount of hair building up on the agitator  18  may reduce the efficiency of the agitator  18  and/or causing damage to the robot cleaning apparatus  10  (e.g., the rotation systems  24  or the like). To address the problem of hair wrapping around the agitator  18 , the agitator  18  includes a plurality of bristles  40  aligned in one or more rows or strips as well as one or more sidewalls and/or continuous sidewalls  42  adjacent to at least one row of bristles  40 . The rows of bristles  40  and continuous sidewall  42  are configured to reduce hair from becoming entangled in the bristles  40  of the agitator  18 . Optionally, the combination of the bristles and sidewall  42  may be configured to generate an Archimedes screw force that urges/causes the hair to migrate towards one or more collection areas and/or ends of the agitator  18 . The bristles  40  may include a plurality of tufts of bristles  40  arranged in rows and/or one or more rows of continuous bristles  40 . 
     The plurality of bristles  40  extend outward (e.g., generally radial outward) from the elongated agitator body  44  (e.g., a base portion  46 ) to define one or more continuous rows. One or more of the continuous rows of bristles  40  may be coupled (either permanently or removably coupled) to the elongated agitator body  44  (e.g., to a base region  46  of the body  44 ) using one or more form locking connections (such as, but not limited to, a tongue and groove connection, a T-groove connection, or the like), interference connections (e.g., interference fit, press fit, friction fit, Morse taper, or the like), adhesives, fasteners overmoldings, or the like. 
     The rows of bristles  40  at least partially revolve around and extend along at least a portion of the longitudinal axis/pivot axis PA of the elongated agitator body  44  of the agitator  18 . As defined herein, a continuous row of bristles  40  is defined as a plurality of bristles  40  in which the spacing between adjacent bristles  40  along the axis of rotation  20  is less than or equal to 3 times the largest cross-sectional dimension (e.g., diameter) of the bristles  40 . 
     As mentioned above, the plurality of bristles  40  are aligned in and/or define at least one row that at least partially revolves around and extends along at least a portion of the longitudinal axis/pivot axis PA of the elongated agitator body  44  of the agitator  18 . For example, at least one of the rows of bristles  40  may be arranged in a generally helical, arcuate, and/or chevron configuration/pattern/shape. Optionally, one or more of the rows of bristles  40  (e.g., the entire row or a portion thereof) may have a constant pitch (e.g., constant helical pitch). Alternatively (or in addition), one or more of the rows of bristles  40  (e.g., the entire row or a portion thereof) may have a variable pitch (e.g., variable helical pitch). For example, at least a portion of the row of bristles  40  may have a variable pitch that is configured to accelerate the migration of hair and/or generally direct debris towards the debris collection chamber  30 . 
     At least one row of bristles  40  is proximate to (e.g., immediately adjacent to) at least one sidewall  42 . The sidewall  42  may be disposed as close as possible to the nearest row of bristles  40 , while still allowing the bristles  40  to bend freely left-to-right. For example, one or more of the sidewalls  42  may extend substantially continuously along the row of bristles  40 . In one embodiment, at least one sidewall  42  extends substantially parallel to at least one of the rows of bristles  40 . As used herein, the term “substantially parallel” is intended to mean that the separation distance between the sidewall  42  and the row of bristles  40  remains within 15% of the greatest separation distance along the entire longitudinal length of the row of bristles  40 . Also, as used herein, the term “immediately adjacent to” is intended to mean that no other structure feature or element having a height greater than the height of the sidewall  42  is disposed between the sidewall  42  and a closest row of bristles  40 , and that the separation distance D between the sidewall  42  and the closest row of bristles  40  is less than, or equal to, 5 mm (for example, less than or equal to 3 mm, less than or equal to 2.5 mm, less than or equal to 1.5 mm, and/or any range between 1.5 mm to 3 mm). 
     One or more of the sidewalls  42  may therefore at least partially revolve around and extend along at least a portion of the longitudinal axis/pivot axis PA of the elongated agitator body  44  of the agitator  18 . For example, at least one of the sidewalls may be arranged in a generally helical, arcuate, and/or chevron configuration/pattern/shape. Optionally, one or more of the sidewalls  42  (e.g., the entire row or a portion thereof) may have a constant pitch (e.g., constant helical pitch). Alternatively (or in addition), one or more of the sidewalls  42  (e.g., the entire row or a portion thereof) may have a variable pitch (e.g., variable helical pitch). 
     While the agitator  18  is shown having a row of bristles  40  with a sidewall  42  arranged behind the row of bristles  40  as the agitator  18  rotates about the pivot axis PA, the agitator  18  may include one or more sidewalls  42  both in front of and behind the row of bristles  40 . As noted above, one or more of the sidewalls  42  may extend outward from a portion of the elongated agitator body  44  as generally illustrated in  FIG. 3 . For example, one or more of the sidewalls  42  may extend outward from the base  46  of the elongated agitator body  44  from which the row of bristles  40  is coupled and/or may extend outward from a portion of an outer periphery  48  of the elongated agitator body  44 . Alternatively (or in addition), one or more of the sidewalls  42  may extend inward from a portion of the elongated agitator body  44 . For example, the radially distal-most portion of the sidewall  42  may be disposed at a radial distance from the pivot axis PA of the elongated agitator body  44  that is within 20 percent of the radial distance of the adjacent, surrounding periphery of the elongated agitator body  44 , and the proximal-most portion of the sidewall  42  (i.e., the portion of the sidewall  42  which begins to extend away from the base  46 ) may be disposed at a radial distance that is less than the radial distance of the adjacent, surrounding periphery of the elongated agitator body  44 . As used herein, the term “adjacent, surrounding periphery” is intended to refer to a portion of the periphery of the elongated agitator body  44  that is within a range of 30 degrees about the pivot axis PA. 
     The agitator  18  may therefore include at least one row of bristles  40  substantially parallel to at least one sidewall  42 . According to one embodiment, at least a portion (e.g., all) of the bristles  40  in a row may have an overall height Hb (e.g., a height measured from the pivot axis PA) that is longer than the overall height Hs (e.g., a height measured from the pivot axis PA) of at least one of the adjacent sidewalls  42 . Alternatively (or in addition), at least a portion (e.g., all) of the bristles  40  in a row may have a height Hb that is 2-3 mm (e.g., but not limited to, 2.5 mm) longer than the height Hs of at least one of the adjacent sidewalls  42 . Alternatively (or in addition), the height Hs of at least one of the adjacent sidewalls  42  may be 60 to 100% of the height Hb of at least a portion (e.g., all) of the bristles  40  in the row. For example, the bristles  40  may have a height Hb in the range of 12 to 32 mm (e.g., but no limited to, within the range of 18 to 20.5 mm) and the adjacent sidewall  42  may have a height Hs in the range of 10 to 29 mm (e.g., but no limited to, within the range of 15 to 18 mm). 
     The bristles  40  may have a height Hb that extends at least 2 mm. beyond the distal-most end of the sidewall  42 . The sidewall  42  may have a height Hs of at least 2 mm from the base  52 , and may up a height Hs that is 50% or less of the height Hb of the bristles  40 . At least one sidewall  42  should be disposed close enough to the at least one row  46  of bristles  40  to increase the stiffness of the bristles  40  in at least one front-to-back direction as the agitator  18  is rotated during normal use. The sidewall  42  may therefore allow the bristles  40  to flex much more freely in at least one side-to-side direction compared to a front-to-back direction. For example, the bristles  40  may be 25%-40% (including all values and ranges therein) stiffer in the front-to-back direction compared to side-to-side direction. According to one embodiment, the sidewall  42  may be located adjacent to (e.g., immediately adjacent to) the row  46  of bristles  40 . For example, the distal most end of the sidewall  42  (i.e., the end of the sidewall  42  furthest from the center of rotation PA) may be 0-10 mm from the row  46  of bristles  40 , such as 1-9 mm from the row  46  of bristles  40 , 2-7 mm from the row  46  of bristles  40 , and/or 1-5 mm from the row  46  of bristles  40 , including all ranges and values therein. 
     According to one embodiment, the sidewall  42  includes flexible and/or elastomeric. Examples of a flexible and/or elastomeric material include, but are not limited to, rubber, silicone, and/or the like. The sidewall  42  may include a combination of a flexible material and fabric. The combination of a flexible material and fabric may reduce wear of the sidewall  42 , thereby increasing the lifespan of the sidewall  42 . The rubber may include natural and/or synthetic, and may be either a thermoplastic and/or thermosetting plastic. The rubber and/or silicone may be combined with polyester fabric. In one embodiment, sidewall  42  may include cast rubber and fabric (e.g., polyester fabric). The cast rubber may include natural rubber cast with a polyester fabric. Alternatively (or in addition), the cast rubber may include a polyurethane (such as, but not limited to, PU 45 Shore A) and cast with a polyester fabric. 
     Because the sidewall  42  may be assembled on a helical path, there is a requirement for the top edge and bottom edge of the sidewall  42  to follow different helices each with a different helical radius. When a flexible material with reinforcement is selected to pass life requirements, the stretch required along these edges should be accounted for in order for the as-assembled sidewall  42  position to agree with the different helical radius and helical path of each edge (because the fiber materials of the composite sidewall  42  can reduce the flexibility of the sidewall  42 ). If this is not meet, then the distal end of the sidewall  42  may not be positioned at a constant distance from the bristles  40  (e.g., within 10 mm as described herein). Therefore, the sidewall  42  geometry and the material choices should be selected to satisfy the spatial/positional requirements of the sidewall  42 , the flexibility required to perform the anti-wrap function, and the durability to withstand normal use in a vacuum cleaner. The addition of a fabric may be useful in higher agitator rotation speed applications (e.g., but not limited to, upright vacuum applications). 
     The agitator  18  (e.g., the bristles  40 ) should be aligned within the agitator chamber  20  such that the bristles  40  are able to contact the surface to be cleaned. The bristles  40  should be stiff enough in at least one of the directions of arrows R to engage the surface to be cleaned (e.g., but not limited to, carpet fibers) without undesirable bending (e.g., stiff enough to agitate debris from the carpet), yet flexible enough to allow side-to-side bending. Both the size (e.g., height Hs) and location of the sidewalls  42  relative to the row of bristles  40  may be configured to generally prevent and/or reduce hair from becoming entangled around the base or bottom of the bristles  40 . The bristles  40  may be sized so that when used on a hard floor, it is clear of the floor in use. However, when the surface cleaning apparatus  10  is on carpet, the wheels  16  will sink in and the bristles  40  will penetrate the carpet. The length of bristles  40  may be chosen so that it is always in contact with the floor, regardless of floor surface. Additional details of the agitator  18  (such as, but not limited to, the bristles  40  and sidewall  42 ) are described in copending U.S. Patent Application Ser. No. 62/385,572 filed Sep. 9, 2016, which is fully incorporated herein by reference. 
     With reference to  FIGS. 2 and 3 , the robot cleaning apparatus  10  may also include one or more debriders  50 . The debriders  50  includes a plurality of fingers, ribs, and/or teeth  52  forming a comb-like structure that extends along all or a portion of the length of the agitator  18  which includes the bristles  40  and/or sidewalls  42 . The fingers  52  are configured to extend (e.g., protrude) from a portion of the robot cleaning apparatus  10  (such as, but not limited to, the body  12 , agitator chamber  20 , bottom surface  24 , and/or debris collection chamber  30 ) generally towards the agitator  18  such that at a portion of the fingers  52  contact an end portion of the bristles  40  and/or one or more of the sidewalls  42 . Rotation of the agitator  18  causes the fingers  52  of the debrider  50  to pass between the plurality of bristles  40  and contact one or more of the more of the sidewalls  42  (e.g., as generally illustrated in  FIG. 4 ), thereby preventing hair from becoming entangled on the agitator  18 . It should be appreciated that the shape or the fingers, ribs, and/or teeth  52  are not limited to those shown and/or described in the instant application unless specifically claimed as such. 
     According to one embodiment, at least some of the fingers  52  (e.g., all of the fingers  52 ) extend generally towards the agitator  18  such that a distal most end of the fingers  52  is within 2 mm of the sidewall  42  as the sidewall  42  rotates past the fingers  52 . As such, the fingers  52  may or may not contact the sidewall  42 . 
     Alternatively (or in addition), at least some of the fingers  52  (e.g., all of the fingers  52 ) extend generally towards the agitator  18  such that a distal most end of the fingers  52  contact (e.g., overlap) the sidewall  42  as the sidewall  42  rotates past the fingers  52 . For example, the distal most end of the fingers  52  may contact up to 3 mm of the distal most end of the sidewall  42 , for example, 1-3 mm of the distal most end of the sidewall  42 , 0.5-3 mm of the distal most end of the sidewall  42 , up to 2 mm of the distal most end of the sidewall  42 , and/or 2 mm of the sidewall  42 , including all ranges and values therein. 
     The fingers  52  may be placed along all or a part of the longitudinal length L of the debrider  50 , for example, either evenly or randomly spaced along longitudinal length L. According to one embodiment, the density of the fingers  52  (e.g., number of fingers  52  per inch) may be in the range of 0.5-16 fingers  52  per inch such as, but not limited to, 1-16 fingers  52  per inch, 2-16 fingers  52  per inch, 4 to 16 fingers  52  per inch and/or 7-9 fingers  52  per inch, including all ranges and values therein. For example, the fingers  52  may have a 2-5 mm center to center spacing, a 3-4 mm center to center spacing, a 3.25 mm center to center spacing, a 1-26 mm center to center spacing, up to a 127 mm center to center spacing, up to a 102 mm center to center spacing, up to a 76 mm center to center spacing, up to a 50 mm center to center spacing, a 2-26 mm center to center spacing, a 2-50.8 mm center to center spacing, and/or a 1.58-25.4 mm center to center spacing, including all ranges and values therein. 
     The width of the fingers  52  (e.g., also referred to as teeth) may be configured to occupy a minimum width subject to manufacturing and strength requirements. The reduced width of the fingers  52  may minimize wear on the agitator  18  and facilitate airflow between the fingers  52  for clearing of hair. The collective widths of the plastic fingers  52  may be 30% or less than the total width of the debrider  50 , particularly when the debrider  50  is plastic. 
     The width of the fingers  52  along the profile and brush roll axis PA may be based on structural and molding requirements. The profile of the distal end of the fingers  52  may be arcuate (e.g., rounded) or may form a sharp tip (e.g., the leading edge  54  and the trailing edge  56  may intersect at the inflection point to form an acute angle). According to one embodiment, the profile of the distal end of the fingers  52  may be rounded and smooth, based on material and production factors. For example, the profile of the distal end of the fingers  52  may be 0.6-2.5 mm in diameter (such as, but not limited to, 1-2 mm in diameter and/or 1.6 mm in diameter) for a 28 mm diameter agitator  18 . 
     The root gap of the fingers  52  (e.g., the transition between adjacent fingers  52 ) may have a radial gap clearance that is from 0 to 15% of the major diameter of the agitator  18 . For example, the root gap of the fingers  52  may be between 2-7% of the major diameter of the agitator  18  such as, but not limited to, 3-6% of the major diameter of the agitator  18  and/or 5.4% of the major diameter of the agitator  18 . By way of a non-limiting example, the root gap of the fingers  52  may be a 1.5 mm gap for a 28 mm agitator  18 . 
     While the fingers  52  are illustrated being spaced in a direction extending along a longitudinal length L of the debrider  50  that is generally parallel to the pivot axis PA of the agitator  18 , it should be appreciated that all or a portion of the fingers  52  may extend along one or more axes (e.g., a plurality of axes) in one or directions that are transverse to the pivot axis PA (e.g., but not limited to, a V shape). 
     Turning now to  FIG. 5  which is a close up of region V in  FIG. 2 , the fingers  52  include a leading edge  54  and a trailing edge  56 . The leading edge  54  is defined as the portion (e.g., surface) of the finger  52  which faces towards and initially contacts the agitator  18  (e.g., the bristles  40 ) as the agitator  18  rotates during normal use, while the trailing edge  56  is defined as the generally opposite side of the finger  52 . The region of the leading edge  54  that contact/engages the bristles  40  is defined as the engagement portion (e.g., surface)  58 . 
     With reference to  FIGS. 6 and 7 , the debrider  50  may be located within the agitator chamber  20  such that the fingers  52  contact the agitator  18  in a region where the bristles  40  of the agitator  18  are moving generally upward (e.g., away from the surface  60  to be cleaned). For example, the debrider  50  may be disposed proximate to an upper portion of the entrance/inlet  62  to the debris collection chamber  30 . In at least one embodiment, the debris collection chamber  30  may be removable from the body  12  and the debrider  50  may be coupled to the debris collection chamber  30  such that the debrider  50  is removed from the body  12  with the debris collection chamber  30 . 
     The engagement portion  58  of at least one leading edge  54  of a finger  52  may be disposed at an angle LEA that may be defined as the angle formed by a straight line extending between the inner and outer most positions of the engagement portion  58  (excluding the tip radius, if any) and a line extending normal from the outer most position of the engagement portion  58 . According to this definition, the angle LEA may be between 0 and 40 degrees in the direction towards the front of the robot cleaning apparatus  10  (e.g., generally in the direction of arrow F) as shown in  FIG. 6 , and/or may be between 0 and 5 degrees in the direction towards the back of the robot cleaning apparatus  10  (e.g., generally opposite the direction of arrow F) as shown in  FIG. 7  (please note that the engagement portion  58  in  FIG. 7  is not shown within the described region, however, the lines defining LEA in  FIG. 7  correspond to the recited description). 
     As noted herein, the debrider  50  may be located anywhere within the agitator chamber  20  and/or opening  22 . According to one embodiment, the angle LEA of the engagement portion  58  of at least one leading edge  54  of a finger  52  may be defined as the angle formed by a straight line extending between the inner and outer most positions of the engagement portion  58  (excluding the tip radius, if any) and a straight line extending between a midpoint of the finger  52  at the outer most position of the engagement portion  58  and the center of rotation (e.g., pivot axis) of the agitator  18 , as generally illustrated in  FIG. 8 . According to this definition, the angle LEA may be between 5 and 50 degrees. Alternatively, the angle LEA of the engagement portion  58  of at least one leading edge  54  of a finger  52  may be defined as the angle formed by a straight line extending between the inner and outer most positions of the engagement portion  58  (excluding the tip radius, if any) and a straight line extending between the outer most position of the engagement portion  58  and the center of rotation (e.g., pivot axis) of the agitator  18 , as generally illustrated in  FIG. 9 . According to this definition, the angle LEA may be between 5 and 60 degrees and/or between 15 and 90 degrees, for example, 25 degrees. In all cases, a straight line extending between the inner and outer most positions of the engagement portion  58  does not pass through the center of rotation (e.g., pivot axis) of the agitator  18 . 
     Turning now to  FIG. 10 , one embodiment of a debris collection chamber  30  is generally illustrated. The debris collection chamber  30  includes a chamber body  64  and a movable lip/cover  66  that define one or more debris collection cavities  68 . The debris collection chamber  30  includes at least one entrance  62  and, optionally, one or more outlets  69  which are configured to be in fluid communication with a vacuum source/blower. As noted herein, the debrider  50  may be located proximate to the entrance  62  of the debris collection chamber  30 . According to one embodiment, at least one debrider  50  may be mounted, coupled, and/or otherwise secured to the lid  66 . Alternatively (or in addition), the least one debrider  50  may be mounted, coupled, and/or otherwise secured to the chamber body  64 . In either embodiment, the lid  66  may optionally be coupled to the chamber body  64  by way of one or more hinges  70 . 
     The robot cleaning apparatus  10  may also include one or more debrider cleaners. As noted herein, hair that is removed from the agitator  18  may collect on the fingers  52  of the debrider  50 . This hair must be eventually removed from the debrider  50 . The debrider cleaner may include a plurality of debrider cleaner fingers and/or gratings that are configured to remove the hair collected on the fingers  52  of the debrider  50  when the user moves the debrider cleaner fingers/gratings relative to the debrider  50 , without the user having to contact the hair. According to one embodiment, one or more of the debriders  50  are coupled to the lid  66  and one or more of the debrider cleaner fingers/gratings are coupled to the chamber body  64 . Alternatively (or in addition), one or more of the debriders  50  are coupled to the chamber body  64  and one or more of the debrider cleaner fingers/gratings are coupled to the lid  66 . In either case, the debrider  50  moves relative to the debrider cleaner fingers/gratings as the user removes the lid  66  and/or swings the lid  66  open from the chamber body  64 , for example, while empting the debris cavity  68  of the debris collection chamber  30 . 
     According to yet another embodiment, at least one of the debriders  50  is configured to be retracted or extended (for example into a portion of the chamber body  64 , debris cavity  68 , and/or lid  66 ) and the debrider cleaner fingers/gratings remain substantially stationary. Alternatively (or in addition), at least one of the debrider cleaner fingers/gratings is configured to be retracted or extended (for example into a portion of the chamber body  64 , debris cavity  68 , and/or lid  66 ) and the debriders  50  remain substantially stationary. In all cases, the debrider cleaner fingers/gratings are in configured to move within close proximity to (e.g., within 1 mm) and/or contact the fingers  52  of the debrider  50  during the relative movement of the debrider cleaner fingers/gratings and debrider  50 . 
     With reference to  FIGS. 11 and 12 , one embodiment of the debrider  50  and the debrider cleaner  72  is generally illustrated. The debrider  50  is coupled to the lid  66  and the debrider cleaner  72  is coupled to the chamber body  64 . The debrider  50  is located at the entrance/inlet  62  of the debris collection chamber  30  and in close proximity to the exit from the agitator chamber  20 . The exact placement of the debrider  50  may be dictated by optimum placement of the debrider  50  relative to the agitator  18  to collect/remove hair from the agitator  18 . 
     The lid  66  is coupled to the chamber body  64  by one or more hinges  70  that are located near the debrider  50  (e.g., on the same side of the debris collection chamber  30  as the debrider  50 ). In particular, the lid  66  is shown in the closed position in  FIG. 11  and in the open position in  FIG. 12 . As the user moves the lid  66  from the closed position to the open position (e.g., to empty the collection cavity  68 ), the debrider cleaner fingers/gratings  74  of the debrider cleaner  72  (best seen in  FIGS. 12 and 13 ) pass in close proximity to and/or contact the fingers  52  of the debrider  50 , thereby removing any hair that has been collected by the fingers  52 . The size of the debrider cleaner fingers/gratings  74  of the debrider cleaner  72  will be based, at least in part, on the length of the fingers  52 , the position of the fingers  52  relative to the debrider cleaner fingers/gratings  74 , and the position of the hinge  70  relative to the fingers  52 . 
     Turning now to  FIGS. 14 and 15 , another embodiment of the debrider  50  and the debrider cleaner  72  is generally illustrated. The debrider  50  is coupled to the lid  66  and the debrider cleaner  72  is coupled to the chamber body  64 . The debrider  50  is located at the entrance/inlet  62  of the debris collection chamber  30  and in close proximity to the exit from the agitator chamber  20 . The exact placement of the debrider  50  may be dictated by optimum placement of the debrider  50  relative to the agitator  18  to collect/remove hair from the agitator  18 . The lid  66  is coupled to the chamber body  64  by one or more hinges  70  that are located on the generally opposite side of the debris collection chamber  30  from the debrider  50 . 
     With reference now to  FIGS. 16 and 17 , at least a portion of the trailing edge  56  of the fingers  52  of the debrider  50  may include an arcuate profile. In particular, the trailing edge  56  may have an arcuate profile that generally corresponds to an arc  76  that is centered at the hinge point  70  of the lid  66  and chamber body  64 . When the lid  66  is opened, the fingers  52  of the debrider  50  pass through the debrider cleaner fingers/gratings  74  of the debrider cleaner  72 , and the arc profile of the trailing edge  56  of the fingers  52  allows for a minimal gap and/or constant contact between the trailing edge  56  of the fingers  52  and the debrider cleaner fingers/gratings  74  at all angles while the lid  66  is opened. 
     While the debrider cleaner fingers/gratings  74  have been illustrated as being closed (e.g., gratings), it should be appreciated that the debrider cleaner fingers/gratings  74  may be open (e.g., fingers) similar to a comb. Additionally, it should be appreciated that while the agitator  18 , debrider  50 , and debrider cleaner  72  have been described in combination with a robot cleaning apparatus  10 , the agitator  18 , debrider  50 , and/or debrider cleaner  72  are not limited to a robot cleaning apparatus  10  unless specifically claimed as such. In particular, the agitator  18 , debrider  50 , and/or debrider cleaner  72  may be integrated into any surface cleaning apparatus or surface cleaning head such as, but not limited to, upright vacuums, canister vacuums, handheld vacuums, and the like. 
     Turning now to  FIG. 18 , another embodiment of a surface cleaning apparatus is generally illustrated. The surface cleaning apparatus may include an upright vacuum  100 . The upright vacuum  100  may include a body or housing  12 , optionally one or more wheels and/or more drive devices  14  (such as, but not limited to, one or more wheels and/or tracks driven by one or more electric motors and/or gears), and one or more cleaning devices  16 . While not shown for clarity, the upright vacuum  100  may also include one or more controllers, motors, sensors, and/or power sources (e.g., but not limited to, one or more batteries) disposed within and/or coupled to the body  12 . As is well understood, the controllers, motors, sensors (and the like) may be configured to pick-up (e.g., sweep up) and collect debris (for example, optionally using suction airflow). 
     The cleaning device  16  may include one or more agitators  18  that are rotatably driven at least partially within one or more agitator chambers  20  disposed within/defined by the body  12 . The agitator chambers  20  include one or more openings  22  defined within and/or by a portion of the bottom surface/plate  24  of the body  12 . The agitator  18  is configured to be coupled to the body  12  (either permanently or removably coupled thereto) and is configured to be rotated about a pivot axis PA (e.g., in the direction and/or reverse direction of arrow R) within the agitator chambers  20  by one or more rotation systems  26  (not shown for clarity) as described herein. In the illustrated embodiment, the forward direction of travel of the upright vacuum  100  is generally illustrated by arrow F. 
     In the illustrated embodiment, the upright vacuum  100  includes a primary agitator  18 A and an optional secondary agitator  18 B. When rotated, the agitators  18 A and/or  18 B are configured to pickup and/or sweep debris into one or more debris collection chambers (e.g., dust bins, not shown for clarity), e.g., as generally illustrated by arrow D. The debris collection chambers may be either permanently or removably coupled to the body  12 , and are configured to be in fluid communication with the agitator chamber  20  such that debris collected by the rotating agitator  18  may be stored. Optionally, the agitator chamber  20  and debris chamber are fluidly coupled to a vacuum source (e.g., a vacuum pump or the like, not shown for clarity) for generating a partial vacuum in the agitator chamber  20  and debris collection chamber and to suck up debris proximate to the agitator chamber  22  and/or agitators  18 A and/or  18 B. As may be appreciated, the rotation of the agitators  18 A and/or  18 B may aid in agitating/loosening debris from the cleaning surface. Optionally, one or more filters may be provided to remove any debris (e.g., dust particles or the like) entrained in the partial vacuum air flow. The debris chamber, vacuum source, and/or filters may be at least partially located in the body  12 . Additionally, one or more tubes, ducts, or the like  36  may be provided to fluidly couple the debris chamber, vacuum source, and/or filters. 
     The upright vacuum  100  may include one or more debriders  50 . For example, a primary debrider  50 A may be configured to contact the primary agitator  18 A and a secondary debrider  50 B may optionally be configured to contact the secondary agitator  18 B, e.g., as generally described herein. The debrider  50  may include a plurality of fingers or teeth  52  as generally described herein. 
     The primary agitator  18 A may include an elongated agitator body  44  that is configured to extend along and rotate about a longitudinal/pivot axis PA. The primary agitator  18 A (e.g., but not limited to, one or more of the ends of the agitator  18 ) is permanently or removably coupled to the body  12  and may be rotated about the pivot axis PA by the rotation system. The primary agitator  18 A includes a plurality of bristles  40  and at least one sidewall and/or continuous sidewall  42 . The primary agitator  18 A may include a plurality of bristles  40  aligned in two rows or strips, and a four sidewalls  42 . The bristles  40  may include a plurality of tufts of bristles  40  arranged in rows and/or one or more rows of continuous bristles  40 . The bristles  40  may include a longitudinal axis that extends along a radius of the primary agitator  18 A (e.g., the bristles  40  arranged collinearly with the radius of the primary agitator  18 A such that the longitudinal axis of the bristles  40  passes through the pivot axis PA of the primary agitator  18 A). 
     The bristles  40  may extend radially outward beyond the sidewall  42 . For example, the bristles  40  may extend radially up to 5 mm beyond the sidewall  42 , e.g., between 0.5 mm and 5 mm beyond the sidewall  42 , between 1 mm and 5 mm beyond the sidewall  42 , between 2 mm and 4 mm beyond the sidewall  42 , and/or 3.5 mm beyond the sidewall  42 . If the upright vacuum  100  includes a cord guard  110 , then the bristles  40  should extend below the cord guard  110  and the sidewall  42  should not contact the cord guard  110 . Alternatively, if the upright vacuum  100  does not include a cord guard  110 , then the bristles  40  and the sidewall  42  could be the same length. According to another embodiment, the sidewall  42  may extend beyond the distal most end of the bristles  40 . 
     The primary agitator  18 A may include a sidewall and/or continuous sidewall  42  adjacent to each of the rows of bristles  40 . The bristles  40  preferably lead before the sidewall  42  when the primary agitator  18 A is rotating in the direction of arrow R. The distal end of the sidewall  42  (i.e., the end of the sidewall  42  furthest from the center of rotation PA) may be 0-10 mm from the adjacent row  46  of bristles  40 , such as 1-9 mm from the row  46  of bristles  40 , 2-7 mm from the row  46  of bristles  40 , and/or 1-5 mm from the row  46  of bristles  40 , including all ranges and values therein. 
     It should be appreciated that while the primary agitator  18 A is shown with two rows of bristles  40 , two adjacent sidewalls  42 , and two additional sidewalls  42 , wherein the sidewalls  42  are set apart 90 degrees from one another about the pivot axis PA, the agitator  18  is not limited to this configuration unless specifically claimed as such. For example, the agitator  18  may include more or less than two rows of bristles  40  and/or may include more or less than four adjacent sidewalls  42 . In particular, one or more rows of bristles  40  may not have an adjacent sidewall  42  and/or one or more rows of bristles  40  may include one or more adjacent sidewalls  42 . 
     As described herein, the teeth  52  of the debrider  50  may be configured to contact the sidewall  42  as the agitator  18  is rotated about the pivot axis PA. For example, the distal most end of the teeth  52  may contact up to 10 mm of the distal most end of the sidewall  42 , e.g., up to 6 mm of the distal most end of the sidewall  42 , up to 5 mm of the distal most end of the sidewall  42 , up to 3 mm of the distal most end of the sidewall  42 , 1-6 mm of the distal most end of the sidewall  42 , 1-5 mm of the distal most end of the sidewall  42 , 1-3 mm of the distal most end of the sidewall  42 , 0.5-3 mm of the distal most end of the sidewall  42 , up to 2 mm of the distal most end of the sidewall  42 , and/or 2 mm of the sidewall  42 , including all ranges and values therein. 
     In an embodiment having three or more sidewalls  42  (e.g., but not limited to, an embodiment having four sidewalls  42 ), only two of the sidewalls  42  may contact the debrider  50  as the agitator is rotated about the pivot axis PA. If more than two sidewalls  42  contact the debrider  50  during rotation of the agitator  18 , excessive noise may be created and/or the reliability of the sidewalls  42 , teeth  52  of the debrider  50 , and/or rotation systems  26  may be reduced. 
     It should be appreciated, however, that an agitator  18  may have three or more sidewalls  42  that contact the debrider  50  during rotation of the agitator  18 . Increasing the number of more sidewalls  42  that contact the debrider  50  during rotation of the agitator  18  may increase noise and may increase the wear rate of the teeth  52  of the debrider  50 ; however, the performance of the agitator  18  may increase as the number of sidewalls  42  that contacts the debrider  50  increases. Having more than two sidewalls  42  contacting the debrider  50  may be particularly useful in applications having lower agitator  18  rotation rates and/or smaller nozzles. 
     According to one embodiment, the bristles  40  do not contact the teeth  52  of the debrider  50 . For example, the bristles  40  may be grouped together to form tufts  121  of bristles as generally illustrated in  FIG. 19 . The tufts  121  of bristles  40  may be arranged in one or more rows (e.g., but not limited to linear and/or non-linear rows such as a helical and/or chevron pattern or the like). The teeth  52  of the debrider  50  may be spaced apart from each other such that the tufts  121  of bristles  40  do not contact the teeth  52  as the agitator is rotated about the pivot axis PA. For example, the tufts  121  of bristles  40  may have a cross-section (e.g., but not limited to, a diameter) that is less than the spacing between adjacent teeth  52 . The length, arrangement, and size (e.g., bundle width) of the tufts  121  of bristles  42 , and the spacing between the teeth  52 , are therefore selected such that the tufts  121  of bristles  40  travel in the spaces between the teeth  52  and do not contact the teeth  52 . According to one embodiment, the density of the teeth  52  (e.g., number of teeth  52  per inch) may be in the range of 1-16 teeth  52  per inch such as, but not limited to, 2-16 teeth  52  per inch, for example, 4 to 16 teeth  52  per inch and/or 7-9 teeth  52  per inch, including all ranges and values therein. For example, the teeth  52  may have a 2-5 mm center to center spacing, a 3-4 mm center to center spacing, a 3.25 mm center to center spacing, a 1-26 mm center to center spacing, a 2-26 mm center to center spacing, and/or a 1.58-25.4 mm center to center spacing, including all ranges and values therein. According to one embodiment, the bristles  40  (e.g., but not limited to, the tufts  121  of bristles  40 ) on opposite sides of the agitator  18  may be arranged in the same circumferential cross-section (i.e., not staggered) such that the bristles  40  do not contact the teeth  52  as the agitator  18  rotates about the pivot axis PA. 
     Referring back to  FIG. 18 , the debrider  50 A may be located higher up (e.g., further away) from the surface to be cleaned compared to the debrider  50 B which contacts the secondary agitator  18 B (e.g., a soft roller). The debrider  50 A may be located above the suction inlet  39  such that the suction helps to prevent debris from building up on the teeth  50  of the debrider  50 A. 
     Turning now to  FIGS. 20-23 , another embodiment of the debrider  50  is generally illustrated. In particular, the teeth  52  of the debrider  50  in one or more of the lateral regions  115  may be configured to contact a smaller portion of the sidewall  42  compared to the teeth  52  in the central region  116 . The lateral regions  115  of the debrider  50  may be defined as a region extending from one or more of the ends  117 ,  118  towards the other end of the debrider  50 . The overall length of each lateral region  115  may include approximately up to 25% of the overall length Ld of the debrider  50 , e.g., approximately 1-25% of the overall length Ld of the debrider  50 , approximately 5-25% of the overall length Ld of the debrider  50 , approximately 10-20% of the overall length Ld of the debrider  50 , and/or approximately 10-25% of the overall length Ld of the debrider  50 , including all values and ranges therebetween. The central region  116  may be defined as the remaining region of the debrider  50 . 
     At least some of the teeth  52  in one or more of the lateral regions  115  may contact (e.g., overlap) a portion of the distal most end of the sidewall  42  in a range of 0% to less than 100% compared to the portion of at least some of the teeth  52  in the central region  116  that contact the distal most end of the sidewall  42 . For example, some of the teeth  52  in a lateral region  115  may not contact the sidewall  42  and some of the teeth  52  in the lateral region  115  may contact less of the sidewall  42  compared to the largest overlapping portion of at least some of the teeth  52  in the central region  116  that contact the distal most end of the sidewall  42 . In at least one embodiment, one or more of the teeth  52  in one or more of the lateral regions  115  may contact (e.g., overlap) a portion of the distal most end of the sidewall  42  in a range of 0% to less than 90% compared to the portion of at least some of the teeth  52  in the central region  116  that contact the distal most end of the sidewall  42 , in a range of 0% to less than 80% compared to the portion of at least some of the teeth  52  in the central region  116  that contact the distal most end of the sidewall  42 , in a range of 5% to less than 90% compared to the portion of at least some of the teeth  52  in the central region  116  that contact the distal most end of the sidewall  42 , in a range of 0% to less than 75% compared to the portion of at least some of the teeth  52  in the central region  116  that contact the distal most end of the sidewall  42 , and/or in a range of 5% to less than 75% compared to the portion of at least some of the teeth  52  in the central region  116  that contact the distal most end of the sidewall  42 , including all values and ranges therebetween. For example, the distal most ends of the teeth  52  in the central region  116  may contact 2 mm of the distal most end of the sidewall  42  whereas the teeth  52  in at least one of the lateral regions  115  may not contact the sidewall while other teeth  52  in the same lateral region may contact less than 2 mm of the distal most end of the sidewall  42 . Of course, this is merely an example, and the distal most ends of the teeth  52  in the central region  116  may contact more or less than 2 mm of the distal most end of the sidewall  42 . 
     As such, the teeth  52  of the debrider  50  may be considered to taper from the central region  116  towards one or more of the lateral regions  115 . The tapering of the teeth  52  in one or more of the lateral regions  115  compared to the central region  116  may prevent and/or reduce snapping of the trailing edge of the sidewall  42  as the sidewall  42  traverses (e.g., moves past) the teeth  52  of the debrider  50 . 
     According to one embodiment, the length Lt of the teeth  52  of the debrider  50  in one or more of the lateral regions  115  may be smaller than length Lt of the teeth  52  in the central region  116 . At least some of the teeth  52  of the debrider  50  in a lateral region  115  may have a length Lt that is in a range of 0% to less than 100% of the length Lt of the longest teeth  52  in the central region  116 , in a range of 0% to less than 90% of the length Lt of the longest teeth  52  in the central region  116 , in a range of 0% to less than 80% of the length Lt of the longest teeth  52  in the central region  116 , in a range of 5% to less than 90% of the length Lt of the longest teeth  52  in the central region  116 , in a range of 0% to less than 75% of the length Lt of the longest teeth  52  in the central region  116 , and/or in a range of 5% to less than 75% of the length Lt of the longest teeth  52  in the central region  116 , including all values and ranges therebetween. It should be appreciated that the teeth  52  in the central region  116  may have different dimensions (e.g., lengths) which overlap different portions (e.g., amounts) of the sidewall  42 . 
     With reference to  FIG. 20 , the portion of the distal most end of the sidewall  42  that the teeth  52  in one or more of the lateral regions  115  contact (e.g., overlap) may gradually reduce from the central region  116  towards the ends  117 ,  118 . The reduction in the overlap of the teeth  52  in the lateral region  115  may be generally linear and/or generally non-linear. Alternatively (or in addition), the portion of the distal most end of the sidewall  42  that the teeth  52  in one or more of the lateral regions  115  contact (e.g., overlap) may step down when transitioning from the central region  116  to the lateral regions  115  as generally illustrated in  FIG. 21 . The portion of the distal most end of the sidewall  42  that that the teeth  52  in one or more of the lateral regions  115  contact may be substantially constant in the lateral region  115  and/or may vary. 
     Referring now to  FIGS. 22-23 , the debrider  50  may include only a single lateral region  115   a  with one or more teeth  52  that contact (e.g., overlap) a portion of the distal most end of the sidewall  42  in the range of 0% to less than 100% compared to the portion of at least some of the teeth  52  in the central region  116  that contact the distal most end of the sidewall  42 . In particular, the location of the tapered lateral region  115   a  (i.e., end  117  or end  118  of the debrider  50 ) is selected based on which end  117 ,  118  of the debrider  50  is the last end to contact the sidewall  42  as the agitator  18  rotates in its normal direction (i.e., the direction of rotation of the agitator  18  during cleaning). The tapered lateral region  115   a  may therefore be considered to be the trailing edge of the debrider  50 , e.g., the last edge or end of the debrider  50  to be in contact with the sidewall  42  as the agitator  18  rotates about the pivot axis PA. As such, the tapered lateral region  115   a  may be selected based on the direction of the rotation of the agitator  18  and/or the direction of the twist of the sidewall  42 . As noted herein, one or more of the teeth  52  in the lateral region  115   a  (e.g., tooth  52   c ) may not contact the sidewall  42  while one or more of the teeth in the lateral region  115   a  (e.g., tooth  52   d ) may contact a portion of the sidewall  42  that is less than the largest portion that a tooth  52  in the central region  116  contacts the sidewall  42  as the agitator  18  rotates about the pivot axis PA. 
     Turning now to  FIG. 24 , another embodiment of an agitator  18  is generally illustrated. The agitator  18  may include one or more lateral regions  135  in which one or more sidewalls  42  have an increased thickness compared to the thickness of the same sidewall  42  in the central region  136 . The lateral regions  125  of the agitator  18  may be defined as a region of the agitator  18  extending from one or more of the ends  137  of the agitator  18  (only a single end shown) towards the other end of the agitator  18 . The overall length of each lateral region  135  may include approximately up to 25% of the overall length La of the agitator  18 , e.g., approximately 1-25% of the overall length La of the agitator  18 , approximately 5-25% of the overall length La of the agitator  18 , approximately 10-20% of the overall length La of the agitator  18 , and/or approximately 10-25% of the overall length La of the agitator  18 , including all values and ranges therebetween. The central region  136  of the agitator  18  may be defined as the remaining region of the agitator  18 . According to one embodiment, the lateral region  135  of the agitator  18  may correspond to (e.g., be the same as) the lateral region  115  of the debrider  50 . 
     In the illustrated embodiment, the agitator  18  may include only a single lateral region  135  having a sidewall  42  with an increased thickness. In particular, the location of the lateral region  135  is selected based on which end of the agitator  18  is the last end to contact the teeth  52  of the debrider  50  as the agitator  18  rotates in its normal direction (i.e., the direction of rotation of the agitator  18  during cleaning). The lateral region  135  may therefore be considered to be the trailing edge of the agitator  18 , e.g., the last edge or end of the sidewall  42  to be in contact with the teeth  52  of the debrider  50  as the agitator  18  rotates about the pivot axis PA. As such, the lateral region  135  may be selected based on the direction of the rotation of the agitator  18  and/or the direction of the twist of the sidewall  42 . 
     At least a portion of the sidewall  42  in one or more of the lateral regions  135  may have a stiffness which is greater than the maximum stiffness of the same sidewall  42  in the central region  136 . The increased stiffness of the sidewall  42  in the lateral region  135  is configured to produce an even amount of deflection of the sidewall  42  along the full length of the sidewall  42  as the agitator  18  rotates about the pivot axis PA (i.e., the sidewall  42  deflects backwards when contacted by the teeth  52  of the debrider  50 ). Without the increased stiffness of the sidewall  42  in the lateral region  135 , the teeth  52  of the debrider  50  will deflect the sidewall  42 , at the trailing edge of the sidewall  42 , up to approximately three times as much as elsewhere on the sidewall  42 , which may cause the sidewall  42  to wear at an accelerated rate in that area. Therefore, the sidewall  42  may be strengthened in the lateral region  135  to achieve the appropriate balance of sidewall  42  geometry (locally increasing the stiffness of the sidewall  42 ) and even deflection across the length of the sidewall  42  (to maintain hair removal function). For example, at least a portion of the sidewall  42  in the lateral region  135  may have a stiffness up to 300% thicker than the largest stiffness of the same sidewall  42  in the central region  136  of the agitator  18 , a stiffness up to 200% stiffer than the largest stiffness of the same sidewall  42  in the central region  136  of the agitator  18 , between 100% and up to 300% stiffer than the largest stiffness of the same sidewall  42  in the central region  136  of the agitator  18 , between 200% and up to 300% stiffer than the largest stiffness of the same sidewall  42  in the central region  136  of the agitator  18 , and/or between 100% and up to 200% stiffer than the largest stiffness of the same sidewall  42  in the central region  136  of the agitator  18 , including all values and ranges therebetween. 
     For example, at least a portion of the sidewall  42  in one or more of the lateral regions  135  may have a thickness which is larger than the maximum thickness of the same sidewall  42  in the central region  136 . The increased thickness of the sidewall  42  in the lateral region  135  is configured to produce an even amount of deflection of the sidewall  42  along the full length of the sidewall  42  as the agitator  18  rotates about the pivot axis PA (i.e., the sidewall  42  deflects backwards when contacted by the teeth  52  of the debrider  50 ). Without the increased thickness of the sidewall  42  in the lateral region  135 , the teeth  52  of the debrider  50  will deflect the sidewall  42 , at the trailing edge of the sidewall  42 , up to approximately three times as much as elsewhere on the sidewall  42 , which may cause the sidewall  42  to wear at an accelerated rate in that area. Therefore, the sidewall  42  may be strengthened in the lateral region  135  to achieve the appropriate balance of sidewall  42  geometry (locally increasing the stiffness of the sidewall  42 ) and even deflection across the length of the sidewall  42  (to maintain hair removal function). For example, at least a portion of the sidewall  42  in the lateral region  135  may have a thickness up to 300% thicker than the largest thickness of the same sidewall  42  in the central region  136  of the agitator  18 , a thickness up to 200% thicker than the largest thickness of the same sidewall  42  in the central region  136  of the agitator  18 , between 100% thick and up to 300% thicker than the largest thickness of the same sidewall  42  in the central region  136  of the agitator  18 , between 200% thick and up to 300% thicker than the largest thickness of the same sidewall  42  in the central region  136  of the agitator  18 , and/or between 100% thick and up to 200% thicker than the largest thickness of the same sidewall  42  in the central region  136  of the agitator  18 , including all values and ranges therebetween. 
     Referring back to  FIG. 19 , one or more of the agitators  18  (e.g., but not limited to, the primary agitator  18 A) may include one or more enlarged end caps  125 . The sidewalls  42  may extend across the elongated body  44  of the agitator  18  and may generally abut against and/or extend into a recess formed in the enlarged end caps  125 . The recess may create overlap between the end of the sidewall  42  strip and the end cap  125  such that hair cannot wrap around the sidewalls  42 . The enlarged end caps  125  may extending radially beyond the distal most portion of the sidewall  42 . For example, the diameter of the enlarged end caps  125  may be larger (e.g., extends radially further) than the sidewall  42 . This configuration may prevent debris (e.g., hair or the like) from migrating laterally from the sidewall  42  beyond the end cap  125 . Put another way, the enlarged end caps  125  may prevent hair from wrapping around the agitator  18  at the ends of the agitator  18 . 
     While the surface cleaning apparatus of  FIGS. 18-24  is shown as an upright vacuum  100 , it should be appreciated that the agitator  18  and/or debrider  50  may be integrated into any surface cleaning apparatus or surface cleaning head such as, but not limited to, robot cleaning apparatus, canister vacuums, handheld vacuums, and the like. 
     While the principles of the invention have been described herein, it is to be understood by those skilled in the art that this description is made only by way of example and not as a limitation as to the scope of the invention. Other embodiments are contemplated within the scope of the present invention in addition to the exemplary embodiments shown and described herein. It will be appreciated by a person skilled in the art that a surface cleaning apparatus and/or agitator may embody any one or more of the features contained herein and that the features may be used in any particular combination or sub-combination. Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention, which is not to be limited except by the claims.