Patent Publication Number: US-11395569-B2

Title: Brushroll for vacuum cleaner

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 15/866,978, filed Jan. 10, 2018, now U.S. Pat. No. 10,602,895, which is a continuation-in-part of U.S. patent application Ser. No. 14/966,139, filed Dec. 11, 2015, now U.S. Pat. No. 9,883,779, which claims the benefit of U.S. Provisional Patent Application No. 62/090,959, filed Dec. 12, 2014, all of which are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND 
     Vacuum cleaners can include an agitator for agitating debris on a surface to be cleaned so that the debris is more easily ingested into the vacuum cleaner. In some cases, the agitator comprises a brushroll that rotates within a base or floor nozzle. Such brushrolls can be rotatably driven by a motor, a turbine fan or a mechanical gear train, for example. Brushrolls typically have a generally cylindrical dowel with multiple bristle tufts extending radially from the dowel. In operation, debris on a surface to be cleaned is swept up by the brushroll; in some cases, elongated debris such as hair may become wrapped around the brushroll and must be removed by a user by manually pulling or cutting the hair off the brushroll. 
     BRIEF DESCRIPTION 
     According to one aspect of the present disclosure vacuum cleaner, comprising a base comprising an agitator chamber and a suction nozzle opening in fluid communication with the agitator chamber, an upright body pivotally mounted to the base and comprising a main support section supporting a cyclonic collection system comprising a cyclone separator, a suction source in fluid communication with the cyclonic collection system and a brushroll positioned within the agitator chamber for rotational movement about a central rotational axis, the brushroll comprising a brush dowel defining a length, the brush dowel configured to be mounted for rotation about the central rotational axis, which extends longitudinally through the brush dowel, a plurality of bristles mounted to the brush dowel along at least a portion of the length, and at least one rib extending radially from the brush dowel. 
     According to another aspect a brushroll for a vacuum cleaner, the brushroll comprising a brush dowel defining a length, the brush dowel configured to be mounted for rotation about a rotational axis, which extends longitudinally through the brush dowel, a plurality of bristles mounted to the brush dowel along at least a portion of the length, and at least one rib extending radially from the brush dowel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a schematic cross section of a conventional brushroll for a vacuum cleaner. 
         FIG. 2  is a view similar to  FIG. 1  showing the brushroll during operation. 
         FIG. 3  is a perspective view of a vacuum cleaner according to a first example of the present disclosure, with a portion cut away for clarity. 
         FIG. 4  is a perspective view of a brushroll for the vacuum cleaner of  FIG. 3 . 
         FIG. 5  is a cross-sectional view of the brushroll taken through line V-V of  FIG. 4 . 
         FIGS. 6-7  are views similar to  FIG. 5  showing the brushroll during operation. 
         FIG. 8  is a perspective view of a brushroll according to a second example of the present disclosure; 
         FIG. 9  is a cross-sectional view of the brushroll taken through line IX-IX of  FIG. 8 . 
         FIG. 10  is a perspective view of a brushroll according to a third example of the present disclosure. 
         FIG. 11  is a cross-sectional view of the brushroll taken through line XI-XI of  FIG. 10 . 
         FIG. 12  is a perspective view of a brushroll according to a fourth example of the present disclosure. 
         FIG. 13  is a cross-sectional view of the brushroll taken through line XIII-XIII of  FIG. 12 . 
     
    
    
     DETAILED DESCRIPTION 
     The present discourse relates to vacuum cleaners and in particular to vacuum cleaners or accessory tools for vacuum cleaners having a rotatable brushroll. In particular, the present disclosure relates to an improved brushroll design which reduces hair wrap. According to one aspect of the present disclosure, a brushroll includes a dowel, a plurality of bristles protruding from the dowel, and a shroud surface which is positioned relative to the bristles to minimize hair wrap. 
     According to another aspect of the present disclosure, a brushroll includes a dowel, a plurality of bristles protruding from the dowel, and a cutting channel which is positioned relative to the bristles to permit hair to be cut from the dowel. 
     According to another aspect of the present disclosure, a brushroll includes concave curved tufting surfaces to which bristle tufts are mounted or secured to minimize hair wrap. 
     According to yet another aspect of the present disclosure, a brushroll includes offset, swept bristle tufts that are tufted at an acute angle to reduce the drive torque required to rotate the brushroll. 
     The brushrolls can be used with various vacuum cleaners, including an upright-type vacuum cleaner, a canister-type vacuum cleaner, a stick vacuum cleaner, an autonomous or robotic vacuum cleaner, or a hand-held vacuum cleaner, or accessory tools therefore. Furthermore, the vacuum cleaner or accessory tool can additionally be configured to distribute a fluid and/or to extract a fluid, where the fluid may for example be liquid or steam. The term “surface cleaning apparatus” as used herein includes both vacuum cleaners and accessory tools for vacuum cleaners, unless expressly noted. 
       FIG. 1  is a schematic cross section of a conventional brushroll  200  for a vacuum cleaner. The brushroll  200  includes a brush dowel  202  configured to be mounted for rotation about a central rotational axis X extending longitudinally through the dowel  202 . The dowel  202  includes a cylindrical core  204  and one or more bristle supports  206  projecting from the core  204 . A plurality of bristles  208  protrude from the bristle supports  206 ; the bristles  208  can be provided in a series of discrete tufts or in a continuous strip. The bristles  208  can be arranged in various patterns on the dowel, including straight, angled, helical, or combinations thereof. 
       FIGS. 1-2  show an exemplary operation of the brushroll  200 . During operation, the brushroll  200  is configured to be rotationally driven in the direction indicated by arrow R. As the bristles  208  come into contact with the surface to be cleaned, the bristles  208  are deflected. Debris, which can include, but is not limited to, dirt, dust, and hair, on the surface to be cleaned is swept up by the brushroll  200 . In the present example, for purposes of simple illustration, a single hair H on the surface is shown as being picked up by the brushroll  200  in  FIG. 1  by the bristles  208  in contact with the surface. The bristles  208  lift the hair H off the surface and around the dowel  202  as the brushroll  200  rotates. 
     In some cases, the hair H may be pulled off the bristles  208  by the suction force of the vacuum cleaner. In other cases, as the bristles  208  holding the hair H continue along the rotational path determined by the dowel  202 , the hair H can become wrapped around the dowel  202 , as shown in  FIG. 2 . 
     As the bristles  208  holding the hair H again come into contact with the surface to be cleaned, the hair H extends from an attachment point P, which is where at least one strand of hair H is attached to at least one bristle  208 . When viewed from the side, the surface to be cleaned defines a surface line S, and the deflected bristles  208  define a bristle deflection line Y, which is the tangent line to the curve defined by the deflected bristles  208  at the attachment point P. A deflection angle A 1  is defined by the included angle formed by the surface line S and a line Z, which is the line orthogonal to the bristle deflection line Y at the intersection of the bristle deflection line Y with the surface line S. The hair H defines a hair wrap line W, which is the line defined by the hair H from the attachment point P where it extends from or leaves the bristles  208 . In some cases, the portion of the hair H extending immediately from the bristles  208  may extend substantially linearly before curving around the dowel  202 , and so that hair wrap line W can follow that linear portion of the hair H. A hair wrap angle A 2  is defined by the included angle formed by the surface line S and the hair wrap line W. It is noted that the hair H can be caught in various locations by the bristles  208 , but that, regardless of where the hair is attached to the bristles, the wrapped hair H will have at least some portion that extends from the bristles  208  in the direction opposite to brushroll rotation R. 
     It has been found that for brushroll designs where the hair wrap angle A 2  is greater than the deflection angle A 1  (in other words, where A 2 &gt;A 1 ), the hair is pulled toward the root of the bristles  208  and becomes tightly wrapped around the dowel  202 . In this case, the hair cannot be pulled off the brushroll  200  by the suction force of the vacuum cleaner, and the user must manually remove the hair. 
     Examples of the present disclosure include brushroll designs in which the hair wrap angle A 2  is less than or equal to the deflection angle A 1  (in other words, where A 2 ≤A 1 ). Such brushrolls prevent or greatly reduce the amount of hair wrap during operation. 
       FIG. 3  is a perspective view of a vacuum cleaner  10  in the form of an upright vacuum cleaner according to a first example of the disclosure. While shown and referred to herein as an upright vacuum cleaner, the vacuum cleaner  10  can alternatively be configured as a stick vacuum cleaner, an autonomous or robotic vacuum cleaner, a hand-held vacuum cleaning device, or as an apparatus having a floor nozzle or a hand-held accessory tool connected to a canister or other portable device by a vacuum hose. Additionally, the vacuum cleaner  10  can be configured to have fluid distribution capability and/or extraction capability. 
     For purposes of description related to the figures, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the disclosure as oriented in  FIG. 3  from the perspective of a user behind the vacuum cleaner, which defines the rear of the vacuum cleaner. However, it is to be understood that the disclosure may assume various alternative orientations, except where expressly specified to the contrary. 
     As illustrated, the vacuum cleaner  10  comprises an upright body  12  pivotally mounted to a lower base  14 . The upright body  12  generally comprises a main support section  16  supporting a collection system  18  for separating and collecting contaminants from a working airstream for later disposal. In one conventional arrangement illustrated herein, the collection system  18  can include a cyclone separator  20  for separating contaminants from a working airstream and a removable dirt cup  22  for receiving and collecting the separated contaminants from the cyclone separator  20 . The cyclone separator  20  can have a single cyclonic separation stage, or multiple stages. In another conventional arrangement, the collection system  18  can include an integrally formed cyclone separator and dirt cup, with the dirt cup being provided with a bottom-opening dirt door for contaminant disposal. It is understood that other types of collection systems  18  can be used, such as centrifugal separators or bulk separators. In yet another conventional arrangement, the collection system  18  can include a filter bag. The vacuum cleaner  10  can also be provided with one or more additional filters upstream or downstream of the collection system  18 . 
     The upright body  12  is pivotally mounted to the base  14  for movement between an upright storage position, shown in  FIG. 3 , and a reclined use position (not shown). The vacuum cleaner  10  can be provided with a detent mechanism, such as a pedal  24  pivotally mounted to the base  14 , for selectively releasing the upright body  12  from the storage position to the use position. The details of such a detent pedal  24  are known in the art, and will not be discussed in further detail herein. 
     The upright body  12  also has an elongated handle  26  extending upwardly from the main support section  16  that is provided with a hand grip  28  at one end that can be used for maneuvering the vacuum cleaner  10  over a surface to be cleaned. A motor cavity  30  is formed at a lower end of the support section  16  and contains a conventional suction source, such as a motor/fan assembly  36 , positioned therein in fluid communication with the collection system  18 . The vacuum cleaner  10  can also be provided with one or more additional filters upstream or downstream of motor/fan assembly. 
     In  FIG. 3 , a lower portion of the vacuum cleaner  10  is cut away to show features of the base  14 . The base  14  can include an upper housing  32  that couples with a lower housing  34  to create a partially enclosed space therebetween. An agitator chamber  38  can be provided at a forward portion of the lower housing  34  for receiving a brushroll  60 . A suction nozzle opening  42  is formed in the lower housing  34  and is in fluid communication with the agitator chamber  38  and the collection system  18 . Wheels  44  can be provided on the base  14  for maneuvering the vacuum cleaner  10  over a surface to be cleaned. 
     The brushroll  60  is positioned within the agitator chamber  38  for rotational movement about a central rotational axis X. A single brushroll  60  is illustrated; however, it is within the scope of the disclosure for dual rotating brushrolls to be used. Moreover, it is within the scope of the disclosure for the brushroll  60  to be mounted within the agitator chamber  38  in a fixed or floating vertical position relative to the chamber  38  and lower housing  34 . 
     The brushroll  60  can be operably coupled to and driven by the motor/fan assembly  36  in the motor cavity  30 . The motor/fan assembly  36  can comprise a motor shaft  46  which is oriented substantially parallel to the surface to be cleaned and protrudes from the motor cavity  30  into a rear portion of the base  14 . A drive belt  48  operably connects the motor shaft  46  to the brushroll  60  for transmitting rotational motion of the motor shaft  46  to the brushroll  60 . Alternatively, a separate, dedicated agitator drive motor (not shown) can be provided within the base  14  to drive the brushroll  60 . 
     The base  14  can further include an optional suction nozzle height adjustment mechanism for adjusting the height of the suction nozzle opening  42  with respect to the surface to be cleaned. A rotatable knob  54  for actuating the adjustment mechanism can be provided on the exterior of the base  14 . In another variation, the suction nozzle height adjustment mechanism can be eliminated. 
     In operation, the vacuum cleaner  10  draws in debris-laden air through the base  14  and into the collection system  18  where the debris, which can include, but is not limited to, dirt, dust, hair, and other debris, is substantially separated from the working air flow, which is generated by the motor/fan assembly  36 . The spinning motor shaft  46  of the motor/fan assembly  36  rotates the brushroll  60  via the drive belt  48  that is operably connected therebetween. Alternatively, a separate, dedicated agitator drive motor can rotate the brushroll  60 . As the brushroll  60  rotates, the bristles sweep across the surface to be cleaned to release and propel debris into the working air flow generated by the motor/fan assembly  36 , which carries the debris into the collection system  18 . The working air flow then passes through the motor cavity  30  and past the motor/fan assembly  36  prior to being exhausted from the vacuum cleaner  10 . The collection system  18  can be periodically emptied of debris. 
       FIG. 4  is a perspective view of the brushroll  60 . The brushroll  60  includes a brush dowel  62  configured to be mounted for rotation about a central rotational axis X extending longitudinally through the dowel  62 . The brush dowel  62  is mounted on an elongated shaft  64  that extends through the center of the dowel  62  and defines the central rotational axis X around which the brushroll  60  rotates. The brushroll  60  illustrated is configured to be rotationally driven in the direction indicated by arrow R. A bearing  66  is mounted on each end of the shaft  64 . In operation, the dowel  62  rotates about the shaft  64  on the bearings  66 . A belt engagement surface  68  extends around the circumference of the dowel  62  near one end, and communicates with the belt  48  ( FIG. 3 ). The belt engagement surface  68  may comprise a pulley. 
     The brush dowel  62  further includes one or more bristle supports  70  which project into the dowel  62 . Bristles  72  protrude from the bristle supports  70 , and can be provided in a series of discrete tufts or in a continuous strip. The bristles  72  can be arranged in various patterns on the dowel  62 , including straight, angled, helical, or combinations thereof. 
     The brushroll  60  is designed to prevent or greatly reduce the amount of hair wrap during operation by providing a shroud surface  74  for wrapping hair. The shroud surface  74  is provided adjacent to the bristles  72  in order to establish a more shallow hair wrap angle, as described in further detail below. 
     In the illustrated example, two bristle supports  70  and two corresponding rows of bristle tufts  76  are provided on the dowel  62 , each tuft  76  containing a plurality of bristles  72 , and extend in a generally helical pattern around the circumference of the dowel  62 . The outer surface of the brush dowel  62  includes opposing curved sections, shown herein as convex curved surfaces  86 , defining the shroud surface  74  and opposing flat sections defining mounting surfaces  78  of the bristle supports  70  from which the tufts  76  project. 
       FIG. 5  is a cross section of the brushroll  60  taken through line V-V of  FIG. 4 . The brush dowel  62  can define a hollow interior  80  that extends along the length of the dowel  62 . The shaft  64  is received within the hollow interior  80 . The bristle supports  70  further include bristle support platforms  82  which project from the mounting surfaces  78  into the hollow interior  80  of the dowel  62 . Bristle holes  84  for the bristle tufts  76  can be formed in the mounting surface  78  and can extend at least partially into the platforms  82 . 
     In one non-limiting example, to produce the brushroll  60  shown in  FIG. 5 , the outer contour of the dowel  62  can be formed using a two-part mold, while the interior of the dowel  62 , including the platforms  82 , can be cored out using an unscrewing core. It is noted that, in order to form the brushroll  60  in a two-part mold, the bristle supports  70  and shroud surfaces  74  may extend 180 degrees or less along the length of the dowel  62  in order to be in the line of draw. The bristle holes  84  can be formed in the dowel  62  by drilling into the dowel  62  after molding, or can be integrally molded with the dowel  62 . The bristle tufts  76  can be assembled with the dowel  62  by pressing bristles  72  into the bristle holes  84  and securing the bristles  72  using a fastener (not shown), such as, but not limited to, a staple, wedge, or anchor. The dowel  62  can comprise a polymeric material, such as polypropylene, acrylonitrile butadiene styrene (ABS), or styrene. The bristles  72  can comprise a polymeric material, such as nylon or polyester, for example, which allows the bristles  72  to flex and deflect when brought into contact with a surface to be cleaned during normal operation. Other manufacturing methods can also be used to produce the brushroll  60  shown in  FIG. 5 . 
     As noted above, the brushroll  60  is designed to prevent or greatly reduce the amount of hair wrap during operation by providing the shroud surface  74  for wrapping hair. In the illustrated example, the brush dowel  62  defines a major diameter D 1 , which is the diameter defined by the smallest circle that can enclose the shroud surface  74  of the dowel  62 . The bristle tufts  76  define a trim diameter D 2 , which is slightly larger than the major diameter D 1 . The flat mounting surfaces  78  are recessed below the major diameter D 1 , and therefore below the shroud surface  74 , which allows the bristles  72  on the flat mounting surfaces  78  to deflect when contacting the surface to be cleaned, while keeping any hair at or near the tip of the bristles  72 . For example, the bristle supports  70  define a minor diameter D 3  of the brush dowel  62 . The minor diameter D 3  can be defined at the tufting locations of the bristle tufts  76  in the bristle supports  70 . The minor diameter D 3  can be less than the major diameter D 1  and the trim diameter D 2 . In the illustrated example, the minor diameter D 3  is the diameter defined by the smallest circle that can touch both mounting surfaces  78  of the bristle supports  70 , at the tufting locations of the bristle tufts  76 . Other configurations for a brushroll having bristle supports  70  and shroud surface  74  may have major and minor diameters D 1 , D 3  defined in other manners, as long as the shroud surface  74  defines D 1  and the bristle supports  70  define D 3 . 
     The outer surface of the brush dowel  62  shown in  FIG. 5  further includes outside corners  88  where the convex curved surfaces  86  defining the shroud surface  74  intersect the opposing flat sections defining mounting surfaces  78 . The outside corners  148  are where the two converging surfaces  78 ,  86  meet. Further, the brush dowel  62  shown in  FIG. 5  is symmetrical about multiple axes, including a first axis of symmetry extending generally along where the minor diameter D 3  is defined, and second axis of symmetry that is orthogonal to the first axis of symmetry, generally where the trim diameter D 2  is shown in  FIG. 5 . 
       FIGS. 6-7  show an exemplary operation of the brushroll  60 . The brushroll  60  is designed to have a hair wrap angle A 2  that is less than or equal to the deflection angle A 1  (in other words, where A 2 ≤A 1 ). During operation, the brushroll  60  rotates in direction R and debris including, but not limited to, dirt, dust, and hair on the surface to be cleaned is swept up by the brushroll  60 . In the present example, for purposes of simple illustration, a single hair H on the surface is shown as being picked up by the brushroll  60  in  FIG. 6  by the bristle tuft  76  in contact with the surface. The bristle tuft  76  lifts the hair H off the surface and around the dowel  62  as the brushroll  60  rotates. In some cases, the hair H may be pulled off the brushroll  60  by the suction force of the vacuum cleaner. In other cases, as the bristle tuft  76  holding the hair H continues along the rotational path determined by the dowel  62 , the hair H can wrap around the shroud surface  74 , as shown in  FIG. 7 , extending from the attachment point P to the bristle tuft  76  and around the dowel  62 . Because the hair wrap angle A 2  is shallower, the hair H remains at or near the tip of the bristle tuft  76  and the hair H is not pulled toward the root of the bristles  208 , nor does the hair H wrap tightly around the dowel  62 . As the bristle tuft  76  holding the hair H again comes into contact with the surface to be cleaned, the hair H can be pulled off the bristle tuft  76  by frictional contact with the surface to be cleaned and the resulting deflection of the bristle tuft  76 . Though the hair H may be returned to the surface, as the vacuum cleaning operation continues, the same hair H may be picked up again by the brushroll  60  and pulled off the brushroll  60  by the suction force of the vacuum cleaner. It is also noted that the brushroll  60  may make one or more revolutions before hair H is pulled off the brushroll  60  by suction force or releasing hair back onto the surface to be cleaned. 
     In one example, the hair wrap angle A 2  of the brushroll  60  can be approximately half of the bristle deflection angle A 1 . Keeping the minor diameter D 3  less than the major diameter D 1  essentially pulls the bristle tips in closer to the shroud surface  74 , such that the trim diameter D 2  remains slightly larger than the major diameter D 1 , and hair wrap can be prevented. If the hair wrap angle A 2  becomes too shallow, essentially by the major diameter D 1  of the shroud surface  74  becoming larger relative to the trim diameter D 2 , the shroud surface  74  may prevent the bristle tufts  76  from engaging the surface to be cleaned. 
       FIG. 8  is a perspective view of a brushroll  90  according to a second example of the disclosure. The brushroll  90  can be used with the vacuum cleaner  10  of  FIG. 3 , as described above, or with other vacuum cleaners and accessory tools, and is designed to accommodate a secondary device for cutting wrapped hair. In one example the secondary device includes scissors or another hand-held cutting implement. The brushroll  90  includes a brush dowel  92  configured to be mounted for rotation about a central rotational axis X extending longitudinally through the dowel  92 . The brush dowel  92  is mounted on an elongated shaft  94  that extends through the center of the dowel  92  and defines the central rotational axis X around which the brushroll  90  rotates. The brushroll  90  illustrated is configured to be rotationally driven in the direction indicated by arrow R. A bearing  96  is mounted on each end of the shaft  94 . In operation, the dowel  92  rotates about the shaft  94  on the bearings  96 . A belt engagement surface  98  extends around the circumference of the dowel  92  near one end, and can communicate with a belt, such as belt  48  ( FIG. 3 ). The belt engagement surface  98  may comprise a pulley. 
     The brush dowel  92  further includes a cylindrical core  100  and one or more bristle supports  102  projecting from the core  100 . Bristles  104  protrude from the bristle supports  102 , and can be provided in a series of discrete tufts or in a continuous strip. The bristles  104  can be arranged in various patterns on the dowel  92 , including straight, angled, helical, or combinations thereof. 
     The brushroll  90  is designed to accommodate a secondary device for cutting wrapped hair by providing at least one standing rib  106  adjacent to the bristles  104  which defines a channel  108  into which scissors or another cutting implement can be inserted to cut hair that is wrapped around the dowel  92 . As shown in  FIG. 8 , the at least one standing rib  106  extends radially from the brush dowel  92  and intersects the row formed by the bristles  104 . 
     In the illustrated example, two rows of bristle supports  102  and two corresponding rows of bristle tufts  110 , each tuft  110  containing a plurality of bristles  104 , are provided on the dowel  92 . The rows extend in a generally helical pattern around the circumference of the dowel  92 . Further, two opposing sets of standing ribs  106  project radially from the dowel  92 , though only one set of visible in  FIG. 8 . Each of the opposing sets of standing ribs  106  is intersecting a corresponding row of bristles  104 . The ribs  106  can extend axially along the core  100  of the dowel  92  in one or more rows to define the channel  108 . Alternatively, the channel  108  can be formed between one standing rib  106  and the bristle support  102 . 
     Circumferential gaps  112  can extend around the dowel  92  to separate adjacent bristle supports  102  and ribs  106 , and further allow the rotating brushroll  90  to clear ribs on the lower housing  34  that prevent carpet from getting drawn into the suction nozzle opening  42  ( FIG. 4 ). 
       FIG. 9  is a cross section of the brushroll  90  taken through line IX-IX of  FIG. 8 . The brush dowel  92  can define a hollow interior  114  that extends along the length of the dowel  92 . The shaft  94  is received within the hollow interior  114 . Bristle holes  116  for the bristle tufts  110  can be formed in the bristle supports  102 . 
     In one non-limiting example, to produce the brushroll  90  shown in  FIG. 9 , the outer contour of the dowel  92 , including the bristle supports  102  and the ribs  106 , can be formed using a two-part mold, while the interior of the dowel  92  can be cored out using an unscrewing core. The ribs  106  are oriented in the line of draw. The bristle holes  116  can be formed in the dowel  92  by drilling into the dowel  92  after molding, or can be integrally molded with the dowel  92 . The bristle tufts  110  can be assembled with the dowel  92  by pressing bristles  104  into the bristle holes  116  and securing the bristles  104  using a fastener (not shown), such as, but not limited to, a staple, wedge, or anchor. The dowel  92  can comprise a polymeric material, such as polypropylene, ABS, or styrene. The bristles  104  can comprise a polymeric material, such as nylon or polyester, for example, which allows the bristles  104  to flex and deflect when brought into contact with a surface to be cleaned during normal operation. Other manufacturing methods can also be used to produce the brushroll  90  shown in  FIG. 9 . 
     During operation, the brushroll  90  rotates in direction R and debris including, but not limited to, dirt, dust, and hair on the surface to be cleaned is swept up by the brushroll  90 . In some cases, hair can wrap around the dowel  92  rather than being pulled off the brushroll  90  by suction force of the vacuum cleaner. In this case, scissors or another cutting implement can be inserted into the channel  108  defined by the ribs  106  to cut that hair that is wrapped around the dowel  92 . 
     In a further example, the height of the standing ribs  106  can be increased so that the outer perimeter defined by the top of the standing ribs  106  forms a shroud surface to minimize the hair wrap angle A 2 , as described for the first example. 
     It should be understood that the brushroll  60  of  FIGS. 4-7  can further be designed to accommodate a secondary device, such as scissors or another hand-held cutting implement, for cutting wrapped hair in a manner similar to the brushroll  90  of  FIGS. 8-9 . In one example, ribs  106  and/or channel  108  can be provided in the dowel  62 . 
       FIGS. 10-11  show a brushroll  120  according to a third example of the disclosure. The brushroll  120  can be used with the vacuum cleaner  10  of  FIG. 3 , as described above, or with other vacuum cleaners and accessory tools, and differs from the first example of the brushroll  60  by having concave, rather than flat, tufting surfaces, as described in further detail below. 
     The brushroll  120  includes a brush dowel  122  configured to be mounted for rotation about a central rotational axis X extending longitudinally through the dowel  122 . The brush dowel  122  is mounted on an elongated shaft  124  that extends through the center of the dowel  122  and defines the central rotational axis X around which the brushroll  120  rotates. The brushroll  120  illustrated is configured to be rotationally driven in the direction indicated by arrow R. A bearing  126  is mounted on each end of the shaft  124 . In operation, the dowel  122  rotates about the shaft  124  on the bearings  126 . A belt engagement surface  128  extends around the circumference of the dowel  122  near one end, and can communicate with a belt, such as belt  48  ( FIG. 3 ). The belt engagement surface  128  may comprise a pulley. 
     The brush dowel  122  further includes one or more bristle supports  130  which project into the dowel  122 . Bristles  132  protrude from the bristle supports  130 , and can be provided in a series of discrete tufts or in a continuous strip. The bristles  132  can be arranged in various patterns on the dowel  122 , including straight, angled, helical, or combinations thereof. 
     The brushroll  120  is designed to prevent or greatly reduce the amount of hair wrap during operation by providing a shroud surface  134  for wrapping hair. The shroud surface  134  is provided adjacent to the bristles  132  in order to establish a more shallow hair wrap angle, the benefits of which are discussed above with respect to the first example of the brushroll  60 . 
     In the illustrated example, two bristle supports  130  and two corresponding rows of bristle tufts  136  are provided on the dowel  122 , each tuft  136  containing a plurality of bristles  132 , and extend in a generally helical pattern around the circumference of the dowel  122 . The overall outer surface of the brush dowel  122  includes opposing convex curved surfaces  138  which together define the shroud surface  134  and opposing concave curved surfaces  140  defining mounting surfaces of the bristle supports  130  from which the tufts  136  project. 
       FIG. 11  is a cross section of the brushroll  120  taken through line XI-XI of  FIG. 10 . The brush dowel  122  can define a hollow interior  142  that extends along the length of the dowel  122 . The shaft  124  is received within the hollow interior  142 . The bristle supports  130  further include bristle support platforms  144  which project from the concave curved surfaces  140  into the hollow interior  142  of the dowel  122 . Bristle holes  146  for the bristle tufts  136  can be formed in the concave curved surfaces  140  and can extend at least partially into the platforms  144 . 
     In one non-limiting example, to produce the brushroll  120  shown in  FIGS. 10-11 , the outer contour of the dowel  122  can be formed using a two-part mold, while the interior of the dowel  122 , including the platforms  144 , can be cored out using an unscrewing core. It is noted that, in order to form the brushroll  120  in a two-part mold, the bristle supports  130  and shroud surfaces  134  may extend 180 degrees or less along the length of the dowel  122  in order to be in the line of draw. The bristle holes  146  can be formed in the dowel  122  by drilling into the dowel  122  after molding, or can be integrally molded with the dowel  122 . The bristle tufts  136  can be assembled with the dowel  122  by pressing bristles  132  into the bristle holes  146  and securing the bristles  132  using a fastener (not shown), such as, but not limited to, a staple, wedge, or anchor. The dowel  122  can comprise a polymeric material, such as polypropylene, acrylonitrile butadiene styrene (ABS), or styrene, for example. The bristles  132  can comprise a polymeric material, such as nylon or polyester, for example, which allows the bristles  132  to flex and deflect when brought into contact with a surface to be cleaned during normal operation. Other manufacturing methods can also be used to produce the brushroll  120  shown in  FIGS. 10-11 . 
     The concave curved surfaces  140  intersect the convex shroud surfaces  138  at outside corners  148  where the two converging surfaces  138 ,  140  meet. Further, the brush dowel  122  shown in  FIG. 11  is symmetrical about multiple axes, including a first axis of symmetry extending generally along where the minor diameter D 3  is defined, and second axis of symmetry that is orthogonal to the first axis of symmetry, generally where the trim diameter D 2  is shown in  FIG. 11 . 
     As noted above, the brushroll  120  is designed to prevent or greatly reduce the amount of hair wrap during operation by providing the shroud surface  134  for wrapping hair. For example, the concave curved surfaces  140  are recessed below the major diameter D 1 , and therefore below the shroud surface  134 , which allows the bristles  132  on the concave curved surfaces  140  to deflect when contacting the surface to be cleaned, while keeping any hair at or near the tip of the bristles  132 . 
     In the illustrated example, the brushroll  120  further includes bristle supports  130  that are defined by concave curved surfaces  140 , rather than flat surfaces  78  as for the first example of the brushroll  60  ( FIG. 5 ). Having concave curved surfaces  140  defining the tufting surfaces of the brushroll  120 , i.e. the surfaces to which the bristle tufts  136  are mounted or secured, can offer improved hair wrap reduction. The concave curved surfaces  140  intersect the convex shroud surfaces  138  at outside corners  148 , shown herein as raised edges  148  which can prevent hair from being wedged at the base of the bristles tufts  136 . With a flat mounting surface, hair may be pulled tight across the mounting surface and toward or to the base of the bristle tuft. However, with the concave curved surfaces  140  defining trough-shaped tufting surfaces prevent hair from being wedged at the base of the tufts  136  because the hair bridging the raised edges  148  create a gap that spaces the hair from the base of the tufts  136 . For the purposes of this description, the term concave curved surface refers to a surface that curves inwardly toward the central rotational axis X, forming a tufting surface that is recessed from the outside corners  148 . Although the concave curved surfaces  140  are shown in the figures symmetric incurvate shapes, non-uniform and non-symmetric inwardly curved recesses are also contemplated. Additionally, non-arcuate recesses are also contemplated, such as planar tufting surfaces or V-shaped tufting surfaces, which are recessed inwardly toward the central rotational axis X, for example. 
     The illustrated example of the brushroll  120  further has the bristle tufts  136  positioned equidistant from the raised edges  148 , and projecting radially from the dowel  122  at a midpoint of the concave curved surfaces  140 . 
     It should be understood that the brushroll  120  of  FIGS. 10-11  can further be designed to accommodate a secondary device, such as scissors or another hand-held cutting implement, for cutting wrapped hair in a manner similar to the brushroll  90  of  FIGS. 8-9 . In one example, ribs  106  and/or channel  108  can be provided in the dowel  122 . 
       FIGS. 12-13  show a brushroll  150  according to a fourth example of the disclosure. The brushroll  150  can be used with the vacuum cleaner  10  of  FIG. 3 , as described above, or with other vacuum cleaners and accessory tools, and differs from the third example of the brushroll  120  by having offset, swept bristle tufts that are tufted at an acute angle, as described in further detail below. 
     The brushroll  150  includes a brush dowel  152  configured to be mounted for rotation about a central rotational axis X extending longitudinally through the dowel  152 . The brush dowel  152  is mounted on an elongated shaft  154  that extends through the center of the dowel  152  and defines the central rotational axis X around which the brushroll  150  rotates. The brushroll  150  illustrated is configured to be rotationally driven in the direction indicated by arrow R. A bearing  156  is mounted on each end of the shaft  154 . In operation, the dowel  152  rotates about the shaft  154  on the bearings  156 . A belt engagement surface (not shown) can extend around the circumference of the dowel  152  and can communicate with a belt, such as belt  48  ( FIG. 3 ). 
     The brush dowel  152  further includes one or more bristle supports  160  which project into the dowel  152 . Bristles  162  protrude from the bristle supports  160 , and can be provided in a series of discrete tufts or in a continuous strip. The bristles  162  can be arranged in various patterns on the dowel  152 , including straight, angled, helical, or combinations thereof. 
     The brushroll  150  is designed to prevent or greatly reduce the amount of hair wrap during operation by providing a shroud surface  164  for wrapping hair. The shroud surface  164  is provided adjacent to the bristles  162  in order to establish a shallower hair wrap angle, the benefits of which are discussed above with respect to the first example of the brushroll  60 . 
     In the illustrated example, two bristle supports  160  and two corresponding rows of bristle tufts  166  are provided on the dowel  152 , each tuft  166  containing a plurality of bristles  162 , and extend in a generally helical pattern around the circumference of the dowel  152 . The overall outer surface of the brush dowel  152  includes opposing convex curved surfaces  168  which together define the shroud surface  164  and opposing concave curved surfaces  170  defining mounting surfaces of the bristle supports  160  from which the tufts  166  project. 
       FIG. 13  is a cross section of the brushroll  150  taken through line XIII-XIII of  FIG. 12 . The brush dowel  152  can define a hollow interior  172  that extends along the length of the dowel  152 . The shaft  154  is received within the hollow interior  172 . Bristle holes  176  for the bristle tufts  166  can be formed in the concave curved surfaces  170 . 
     In one non-limiting example, to produce the brushroll  150  shown in  FIGS. 12-13 , the outer contour of the dowel  152  can be formed using a two-part mold, while the interior of the dowel  152  can be cored out using an unscrewing core. It is noted that, in order to form the brushroll  150  in a two-part mold, the bristle supports  160  and shroud surfaces  164  may extend 180 degrees or less along the length of the dowel  152  in order to be in the line of draw. The bristle holes  176  can be formed in the dowel  152  by drilling into the dowel  152  after molding, or can be integrally molded with the dowel  152 . The bristle tufts  166  can be assembled with the dowel  152  by pressing bristles  162  into the bristle holes  176  and securing the bristles  162  using a fastener (not shown), such as, but not limited to, a staple, wedge, or anchor. The dowel  152  can comprise a polymeric material, such as polypropylene, acrylonitrile butadiene styrene (ABS), or styrene. The bristles  162  can comprise a polymeric material, such as nylon or polyester, for example, which allows the bristles  162  to flex and deflect when brought into contact with a surface to be cleaned during normal operation. Other manufacturing methods can also be used to produce the brushroll  150  shown in  FIGS. 12-13 . 
     As noted above, the brushroll  150  is designed to prevent or greatly reduce the amount of hair wrap during operation by providing the shroud surface  164  for wrapping hair. For example, the concave curved surfaces  170  are recessed below the major diameter D 1 , and therefore below the shroud surface  164 , which allows the bristles  162  on the concave curved surfaces  170  to deflect when contacting the surface to be cleaned, while keeping any hair at or near the tip of the bristles  162 . 
     In the illustrated example, the brushroll  150  further includes bristle supports  160  that are defined by concave curved surfaces  170  which intersect the convex shroud surfaces  168  at outside corners  178  where the two converging surfaces  168 ,  170  meet. The outside corners  178  are shown herein as raised edges  178 , the benefits of which are discussed above with respect to the third example of the brushroll  120 . Still further in the illustrated example, the brushroll  150  includes bristle tufts  166  that are tufted at an acute angle relative to the concave tufting surfaces  170 , i.e. the tufting surfaces to which the bristle tufts  166  are mounted or secured, rather than radially  78  as for the third example of the brushroll  120  ( FIG. 11 ). In particular, the tufts  166  define and lie on a centerline axis  180  extending orthogonally through the center of the tufts  166  and the concave tufting surfaces  170  define a centerline axis  182  extending orthogonally through the center of the concave tufting surfaces  170 , and the axes  180 ,  182  intersect outward of the dowel  152  at an acute angle  184 . This provides a swept or angled tip or terminal end  186  for each tuft  166  that is angled in the direction of rotation R. 
     Further, the bristle tufts  166  are offset on the concave tufting surface  170 , i.e. tufted closer to one edge  178  than the other, or offset from the centerline axis  182 , rather than being at the center of the concave tufting surface as for the third example of the brushroll  120  ( FIG. 11 ) or equidistant from the raised edges  148 . The offset, angled tufts  166  reduce the drive torque required to rotate the brushroll  150 , which can be useful for particular vacuum cleaner examples, including autonomous or robotic vacuum cleaners. Although the bristle tufts  166  in  FIGS. 12-13  are shown as both offset from the centerline axis  182 , and angled relative to the concave tufting surface, other configurations are contemplated. For example, the bristle tufts  166  can be offset, but not angled, i.e. oriented parallel to the centerline axis  182 . Alternatively, the bristle tufts  166  can be tufted at the centerline axis  182 , i.e. not offset, but angled relative to the centerline axis instead of radial thereto as in  FIGS. 10-11 . 
     It should be understood that the brushroll  150  of  FIGS. 12-13  can further be designed to accommodate a secondary device, such as scissors or another hand-held cutting implement, for cutting wrapped hair in a manner similar to the brushroll  90  of  FIGS. 8-9 . In one example, ribs  106  and/or channel  108  can be provided in the dowel  152 . 
     While the brushrolls  60 ,  90 ,  120 ,  150  are described herein as being rotatably driven by a motor, it is understood that the brushroll  60 ,  90 ,  120 ,  150  can be driven by other means, such as, but not limited to, a turbine fan or a mechanical gear train. 
     The vacuum cleaner  10  and various brushrolls  60 ,  90 ,  120 ,  150  disclosed herein provide an improved brushroll design which addresses the problem of hair wrap Examples of the present disclosure include brushroll designs in which the hair wrap angle A 2  is less than or equal to the deflection angle A 1  (in other words, where A 2 ≤A 1 ). Such brushrolls release hair that is not pulled off the brushroll by the suction force of the vacuum cleaner back on to the surface to be cleaned, rather than tightly wrapping the hair on the brushroll. These brushrolls provide the opportunity to prevent or greatly reduce the amount of hair wrap during operation. Other examples of the present disclosure include brushroll designs in which hair can easily be cut off the brushroll. 
     While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation. Reasonable variation and modification are possible with the scope of the foregoing disclosure and drawings without departing from the spirit of the invention which, is defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.