Abstract:
A powered floor sweeper comprises a foot assembly with a motor driven primary agitator and a pair of edge agitators coupled to wheels such that manual propulsion of the sweeper rotates the wheels and thereby the edge agitators. The sweeper includes a slip clutch mechanism to protect the primary agitator and the motor in case the agitator become jammed. Additionally, the sweeper comprises a ramp assembly along an agitator opening to help collect dirt and dust at the primary agitator. A dust bin removably mounted in an open top dust bin recess is in communication with the agitator opening and receives the dirt and dust collected at the agitator opening. Furthermore, the sweeper comprises a handle assembly having a detent mechanism that interacts with a pivot cradle in the foot assembly to retain the handle assembly in a generally vertical position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Patent Application No. 60/521,255, filed Mar. 19, 2004. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to sweepers. In one aspect, the invention relates to a sweeper with a dust bin accessible from the top of the sweeper for facile removal and emptying of the dust bin. In another aspect, the invention relates to a sweeper with a powered agitator and a clutch mechanism therefor. In yet another aspect, the invention relates to a sweeper with a retractable ramp mechanism to facilitate collection of dirt and debris at the agitator opening. In still another aspect, the invention relates to a sweeper with a pivotable handle assembly having a detent that abuts a detent ramp in the foot assembly to retain the handle assembly in a generally vertical position. 
     DESCRIPTION OF THE RELATED ART 
     Sweepers are well known devices for removing dirt, dust, and other debris from a floor surface. Typically, sweepers comprise a foot assembly with at least one primary agitator, such as a horizontal axis brush roll, driven by manual propulsion or some other means, such as a motor. An exemplary powered floor sweeper wherein a rotating sweeper brush is rotated by a direct current electric motor is disclosed in U.S. Pat. No. 4,369,539 to Nordeen. In Nordeen &#39;539, a cavity at a rear end of the sweeper houses a DC motor and a battery supply to provide power for the motor. One problem associated with powered agitators is that the motor, the agitator, and/or the mechanism for coupling the motor to the agitator can be damaged if the agitator becomes jammed or is otherwise unable to rotate. 
     In addition to the primary agitator, floor sweepers can include edge agitators, also driven by manual propulsion or some other means. An exemplary floor sweeper having, in addition to its main brush roller, one or more auxiliary brushes for sweeping debris into the path of the main brush is disclosed in U.S. Pat. No. 3,978,539 to Yonkers. In Yonkers &#39;539, a pair of auxiliary brushes are located at the forward corners of the sweeper housing and rotate in a direction to throw debris along the edge of the sweeper housing towards the middle of sweeper housing where the debris can be picked up by the main rotating brush. Other patents disclosing edge brushes include, for example, U.S. Pat. Nos. 500,976 to Tangenberg; 3,750,215 to Liebscher, 3,818,532 to Leifheit et al.; and 4,484,371 to Pätzold et al. 
     To further facilitate collection of debris, some sweepers comprise a wiper strip or ramp positioned along the opening through which the primary agitator extends for agitating the surface to be cleaned. The wiper strip contacts the surface to be cleaned to prevent the debris from passing under the sweeper during forward movement thereof. The abovementioned Nordeen &#39;539 patent includes such a wiper strip, and another exemplary wiper strip is disclosed in U.S. Pat. No. 2,275,356 to Frank. The position of the Frank &#39;356 wiper strip relative to the surface to be cleaned can be adjusted manually by the operator through a lever. An operator would advantageously desire to raise the wiper strip during reverse movement of the sweeper so that the wiper strip does not push the debris away from the agitator opening. However, manual movement of the wiper strip can be inconvenient for the operator, especially if the operator reciprocally moves the sweeper in forward and rearward directions. 
     Usually, the primary agitator throws the dirt, dust, and other debris into a dust bin. In some sweepers, the dust bin is a cavity that can be emptied by opening a panel in the sweeper housing. Other sweepers comprise a separate dust bin mounted in the sweeper housing, and the dust bin can be removed from the sweeper for emptying. For example, Great Britain U.S. Pat. No. 1,442,587 to Moulinex discloses a sweeper with a separate dust bin that can be removed from the sweeper housing after lifting a cover on the sweeper housing to gain access to the dust bin. Because the user has to lift the cover before removing the dust bin, the process of emptying the dust bin can be awkward, especially if the user has only one free hand. 
     Sweepers also comprise a handle assembly pivotally mounted to the foot assembly for moving the sweeper across the surface to be cleaned. When the sweeper is not in use, the user can rest handle assembly against a wall for storage, or the sweeper can preferably include a mechanism for retaining the handle assembly in a generally vertical storage position. Examples of such retaining mechanisms are disclosed in, for example, U.S. Pat. Nos. 5,361,447 to Ophardt; 2,057,181 to Bloom; 255,823 to Soper, 2,406,247 to Owen; 2,975,450 to Williams; 3,034,163 to Stevens; 4,168,561 to Rosendall; and 5,208,935 to Jailor. An optimal retaining mechanism is simple, reliably holds the handle assembly in the generally vertical position, and can be easily manipulated by the user to move the handle assembly away from the vertical position. 
     Customarily, the sweeper handle assembly comprises an elongated stick-like portion that can be grasped by a user while standing an upright position. A segmented upright pivotal handle for a vacuum cleaner is disclosed in U.S. Pat. No. 6,345,411 to Kato et al., wherein upper handle segments can be removed so that the vacuum cleaner can be utilized as a hand held unit in addition to a conventional upright unit. 
     SUMMARY OF THE INVENTION 
     A sweeper according to one embodiment of the invention comprises a foot housing that forms a dust bin cavity with an open top and an agitator aperture on a bottom portion of the foot housing and that opens toward the surface to be cleaned; a dust bin mounted in the open top dust bin cavity such that the dust bin can be inserted into and removed from the dust bin cavity from above the foot housing, the dust bin having a dust bin inlet in communication with the agitator aperture, and an agitator assembly mounted to the foot assembly and positioned at least partially in the agitator aperture to throw dirt from the surface to be cleaned into the dust bin through the dust bin inlet. 
     In one embodiment, the dust bin further comprises a diverter that distributes dirt within the dust bin when the dirt enters the dust bin through the dust bin inlet. The dust bin further comprises spaced front and rear walls, wherein the dust bin inlet is formed in the front wall and the diverter is formed in the rear wall. The diverter comprises an arcuate wall section that protrudes inward toward the front wall. The arcuate wall section is located at the center of the rear wall. 
     In another embodiment, the dust bin further comprises an integrally molded grip. 
     A sweeper according to one embodiment of the invention comprises a foot housing that forms a dust bin cavity and an agitator aperture in a bottom portion of the foot housing and that opens toward the surface to be cleaned; a dust bin mounted in the dust bin cavity and having a dust bin inlet in communication with the agitator aperture, an agitator rotatably mounted to the foot assembly and positioned at least partially in the agitator aperture to throw dirt from the surface to be cleaned into the dust bin through the dust bin inlet; a motor mounted in the foot assembly and coupled to the agitator to rotate the agitator; and a clutch assembly mounted to the agitator. The clutch assembly comprises a pulley coupled to the motor for rotation therewith; a clutch coupled to the agitator for rotation therewith, the clutch and the pulley having complementary surfaces, wherein the complementary surfaces comprise ramped slip clutch surfaces; and a biasing member positioned between the clutch and the agitator to bias the clutch towards the pulley to mate the complementary surfaces whereby, during normal operation conditions, rotation of the pulley by the motor rotates the clutch and the agitator as the complementary surfaces of the pulley and the clutch mate and rotate together and, during conditions where rotation of the agitator is prevented, the surface of the clutch slips relative to the complementary surface of the pulley while the motor rotates the pulley, the pulley pushes the clutch against the bias of the biasing member, and the biasing member continues to bias the clutch towards the pulley. 
     In one embodiment, the agitator comprises a brush roll rotatably mounted on a horizontally oriented axle, and the clutch assembly is rotatably mounted on the axle adjacent the agitator. The motor comprises a drive shaft with a drive gear fixedly mounted to the drive shaft, and the drive gear is coupled to the pulley by a belt. The motor is powered by a battery. The complementary surfaces can comprise multiple ramped surfaces. For example, the multiple ramped surfaces can be arranged circumferentially around the pulley and the clutch. 
     A sweeper according to another embodiment of the invention comprises a foot housing that forms a dust bin cavity and an agitator aperture in a bottom portion of the foot housing and that opens toward the surface to be cleaned; a dust bin mounted in the dust bin cavity and having a dust bin inlet in communication with the agitator aperture, an agitator rotatably mounted to the foot assembly and positioned at least partially in the agitator aperture to throw dirt from the surface to be cleaned into the dust bin through the dust bin inlet; a retractable ramp movably mounted to the foot housing and positioned at an acute angle to the vertical along an edge of the agitator aperture for movement toward and away from the surface to be cleaned for contact with the surface to be cleaned at least when the retractable ramp is in an extended position; and a pair of wheels rotatably mounted to the foot housing for rotational motion in a forward and rearward direction and to support the foot housing for movement in a forward direction and a rearward direction, the wheels are coupled to the ramp assembly for moving the ramp assembly between the retracted and extended positions in response to the rotation of the wheels between the rearward and forward direction. 
     In one embodiment, the ramp assembly comprises a fixed ramp mounted to the foot assembly and a retractable ramp movable relative to the fixed ramp when the ramp assembly moves between the retracted and extended positions. In one embodiment, at least one of the fixed ramp and the retractable ramp is planar. In another embodiment, at least one of the fixed ramp and the retractable ramp is arcuate. In one embodiment, the retractable ramp is made of a resilient material. 
     In another embodiment, the agitator aperture is defined between front and rear edges, and the ramp extends along the rear edge of the agitator aperture. 
     In another embodiment, the ramp assembly moves to the retracted position when the wheels rotate in a reverse direction. The ramp assembly moves to the extended position when the wheels rotate in a forward direction. 
     In yet another embodiment, the retractable ramp is mounted to float over the surface to be cleaned, picking up dirt and debris when the sweeper moves in a forward direction and riding over the floor surface when the sweeper moves in a reverse direction. 
     Still further according to the invention, a floor cleaning apparatus comprises a housing that forms an agitator aperture in a bottom portion of the housing and that opens toward the surface to be cleaned; a dust collector associated with the housing and in open communication with the agitator aperture; an agitator rotatably mounted to the housing and positioned at least partially in the agitator aperture to move dirt from the surface to be cleaned to the dust collector; and a retractable ramp positioned at an acute angle to the vertical along an edge of the agitator aperture for movement toward and away from the surface to be cleaned for contact with the surface to be cleaned at least when the retractable ramp is in an extended position. 
     In one embodiment, a fixed ramp mounted to the housing and the retractable ramp is movable relative to the fixed ramp. Further, at least one of the fixed ramp and the retractable ramp is planar. In an alternative embodiment, at least one of the fixed ramp and the retractable ramp is arcuate. Further, the retractable ramp can be made of a resilient material. 
     Typically, the agitator aperture is defined between front and rear edges and the retractable ramp extends along the rear edge of the agitator aperture. In one embodiment, the retractable ramp moves to the retracted position when the wheels rotate in a reverse direction. Furthers the retractable ramp assembly moves to the extended position when the wheels rotate in a forward direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front perspective view of a powered sweeper according to the invention, wherein a pivoting handle is in a vertical position. 
         FIG. 2  is a rear perspective view of the sweeper shown in  FIG. 1  with the pivoting handle in a horizontal position. 
         FIG. 3  is an exploded view of the sweeper shown in  FIG. 1 . 
         FIG. 4  is a perspective view of a dust bin from the sweeper shown in  FIG. 1 . 
         FIG. 5  is a plan view of the dust bin shown in  FIG. 4 . 
         FIG. 6  is an exploded view of an agitator assembly of the sweeper shown in  FIG. 1 . 
         FIG. 6A  is a sectional view of a clutch gear assembly taken along line  6 A- 6 A of  FIG. 6 . 
         FIG. 7  is a plan view of the sweeper shown in  FIG. 1  with an upper housing, a brush lens, and the dust bin removed. 
         FIG. 8  is a perspective view of a lower housing of the sweeper shown in  FIG. 1 . 
         FIG. 9A  is a schematic sectional view of the sweeper taken along line  9 - 9  of  FIG. 1  and illustrating a retractable ramp positioned behind the agitator assembly. 
         FIG. 9B  is a schematic sectional view similar to  FIG. 9A  and illustrating an alternative retractable ramp. 
         FIG. 10  is a perspective view of a lower handle assembly from the sweeper shown in  FIG. 1 . 
         FIG. 11  is a schematic sectional view of the sweeper taken along line  11 - 11  of  FIG. 1 . 
         FIG. 12  is a schematic sectional view of the sweeper taken along line  12 - 12  of  FIG. 2 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings and to  FIGS. 1 and 2  in particular, a powered sweeper  10  according to the invention comprises a handle assembly  12  pivotally mounted to a foot assembly  14 . The handle assembly  12  comprises a plurality of upper handle segments  16 , only one of which is shown in phantom in  FIG. 1 , and a lower handle assembly  18 . The handle segments  16  are removably joined together in the manner shown, for example, in U.S. Pat. No. 6,345,411 to Kato et al., which is incorporated herein by reference in its entirety. The lower handle assembly  18  comprises a lower grip  20  and an engagement aperture  22  that removably receives a projection (not shown) of the upper handle segment  16  to secure the upper handle segments  16  to the lower handle assembly  18  in a generally linear arrangement. The powered sweeper  10  can be used in an upright mode with one or more of the upper handle segments  16  mounted to lower handle assembly  18  so that a user can stand generally upright while grasping one of the handle segments  16  for maneuvering the powered sweeper  10  over the surface to be cleaned. Alternatively, the powered sweeper  10  can be used in a hand-held mode by removing the upper handle segments  16  and grasping the lower grip  20  for manipulating the powered sweeper  10  over the surface to be cleaned.  FIG. 1  depicts the powered sweeper  10  with the handle segments  16  attached to the lower handle assembly  18  for use of the powered sweeper  10  in the upright mode, and  FIG. 2  depicts the powered sweeper  10  with the handle segments  16  detached from the lower handle assembly  18  for use of the powered sweeper  10  in the hand-held mode. 
     The foot assembly  14  comprises a lower housing  24  and an upper housing  26 , which, when mated, form a cavity therebetween to house various components. A plurality of bosses  96  ( FIG. 8 ) extend upwardly from the lower housing  24  and mate with corresponding structures (not shown) in upper housing  26 , and the lower housing  24  is secured to the upper housing  26  with screws or other suitable fastening devices. The foot assembly  14  is a generally rectangular structure where, by way of reference, the lower handle assembly  18  is located at a rearward portion of the foot assembly  14  while a brush housing  28  is located at a forward end of the foot assembly  14 . A pivot recess  38  is formed in the upper housing  26  to accommodate pivotal movement of the lower handle assembly  18  relative to the foot assembly  14 . The pivot recess  38  accommodates pivotal movement of the handle assembly  12  between a generally vertical storage position illustrated in  FIG. 1  and a generally horizontal position illustrated in  FIG. 2 . The foot assembly  14  is supported on the surface to be cleaned by a pair of wheels  30  are located on the rear corners of the foot assembly  14  and a set of rollers (not shown) located near the brush housing  28  on an underside of the lower housing  24 . 
     Referring additionally to  FIG. 3 , the upper housing  26  and the lower housing  24  form a dust bin cavity  33  sized to removably receive a dust bin  32 . The upper housing  26  has a generally centrally located aperture  31  that provides access to the dust bin cavity  33  and through which the dust bin  32  passes during insertion into the dust bin cavity  33 . The dust bin  32  comprises a dust bin grip  34  to facilitate manual manipulation of the dust bin  32  by the user. To remove the dust bin  32  from the dust bin cavity  33 , the user simply grasps the dust bin grip  34  and lifts the dust bin  32  in a generally upward motion away from the foot assembly  14 . Referring additionally to  FIGS. 4 and 5 , the dust bin  32  further comprises a chamber  118  formed by a floor  120 , a pair of opposing side walls  122  oriented generally perpendicular to the floor  120 , and a back wall  124  that joins rear edges of the side walls  122 . The back wall  124  curves inward to form an arcuate wall section  126  for accommodating pivotal movement of the lower handle assembly  18  between the vertical and the horizontal positions. The arcuate wall section  126  also functions as a debris diverter for equally distributing debris along the width of the dust bin chamber  118 . The chamber  118  is also partially defined by a front wall  128  that extends upward from the floor  120  and joins front edges of the side walls  122 . The front wall  128  is approximately half the height of the side walls  122  to define a dust bin inlet aperture  130  above the front wall  128  and between the side walls  122 . The dust bin inlet aperture  130  is further defined by a dust bin top  132  that is fixedly attached to upper edges of the sidewalls  122  and the back wall  124 . The dust bin top  132  comprises the dust bin grip  34 , which is integrally formed therewith such that a space formed between the dust bin top  132  and the dust bin grip  34  is sufficient to allow fingertip grip for removal of the dust bin  32  from the foot assembly  14 . 
     In addition to providing access to the dust bin cavity  33 , the aperture  31  in the upper housing  26  extends into the brush housing  28 , and the portion of the upper housing  26  that extends into the brush housing  28  is closed by a brush lens  36  preferably made of a translucent material so that the user can view a agitator assembly  48  mounted within the brush housing  28 . The agitator assembly  48  will be described in more detail hereinafter. 
     With continued reference to  FIGS. 1 ,  2  and  3 , the upper housing  26  includes a plurality of motor exhaust apertures  40  formed in the rearward portion thereof. The motor exhaust apertures  40  communicate with a corresponding motor cavity  60  formed between the lower housing  24  and the upper housing  26 . The motor cavity  60  holds a brush motor  58  has a rotatable drive shaft  59  with a brush drive gear  82  fixedly attached thereto. The brush motor  58  is powered by a portable power source in the form of a battery pack  62  located in a battery cavity  64  formed in a rearward portion of the lower housing  24 . The battery pack  62  can comprise any commonly known battery type, preferably a rechargeable nickel cadmium (NiCad), nickel metal hydride (NiMH), or lithium battery. A light source, such as a light emitting diode (LED)  42 , mounted to the rearward portion of the upper housing  26  and is in electrical communication with the battery pack  62  to provide to the user a visual indication of a charge condition of the battery pack  62 . The LED  42  can be a single LED or can be more than one LED. When more than one LED is used, at least one LED is preferably red, and at least one other LED is preferably green. The upper housing  26  supports a pivotable switch cover  45  biased to a position where it is generally flush with the upper housing  26 . The switch cover  45  is in operative communication with an electrical switch  66  located beneath the switch cover  45  such that depression of the switch cover  45  actuates the switch  66 . The electrical switch  66  is located adjacent the battery pack  62  and is supported by a plurality of ribs formed in the lower housing  24 . The electrical switch  66  electrically couples the brush motor  58  and the battery pack  62 , and depression of the switch cover  45  either closes the electrical switch  66  to turn the brush motor  58  on or opens the electrical switch  66  to turn the brush motor  58  off. A charging jack  44  accessible from the rear portion of the foot assembly  14  interfaces with a separate, conventional electrical power transformer and power cord (not shown) to provide an electrical connection between a power source and the internal battery pack  62  to charge the battery pack  62 . 
     Referring now to  FIG. 6 , the agitator assembly  48  rotatably mounted in the brush housing  28  contacts the surface to be cleaned through an elongated agitator aperture  46  formed in a forward lower portion of the lower housing  24 . The agitator assembly  48  comprises a support in the form of a brush dowel  50  onto which a plurality of bristles  52  are affixed in a commonly known manner. The brush dowel  50  is mounted on a horizontally oriented axle  93 , and the bristles  52  extend through the agitator aperture  46  to contact and agitate the surface to be cleaned and throw dirt and dust from the agitator aperture  46  into the dust bin  32  through the dust bin inlet aperture  130 . The agitator assembly  48  further comprises a first bearing  54  located on a first end of the brush dowel  50  for supporting the first end of the brush dowel  50  in the foot assembly  14  and a second bearing  55  on a second, opposite end of the brush dowel  50  for supporting the second end of the brush dowel  50  in the foot assembly  14 . The first and second bearings  54 ,  55  are rotatably mounted between pairs of mating ribs  57  on the upper and lower housings  26 ,  24  of the foot assembly  14 . 
     Referring to  FIGS. 6 and 6A , the agitator assembly  48  further comprises a clutch gear assembly  56  mounted on the axle  93  adjacent the second end of the brush dowel  50 . The clutch gear assembly  56  comprises a spring  86  positioned between the second bearing  55  and a clutch  88 . The spring  86  biases the clutch  88  into mating contact with a clutch pulley  90 , and the mating ends of the clutch  88  and the clutch pulley  90  comprise complementary first and second ramped surfaces  92 ,  94 . The opposite end of the clutch  88  is keyed with the brush dowel  50  so that rotation of the clutch  88  induces rotation of the brush dowel  50 . Furthermore, the brush dowel  50  and the clutch  88  are designed so that the clutch  88  can move axially relative to the brush dowel  50 . A retaining washer  91  secures the clutch pulley  90 , the clutch  88 , and the spring  86  on a portion of the axle  93  that protrudes from the second end of the brush dowel  50 . A brush drive belt  84  couples the clutch pulley  90  to the brush drive gear  82  so that rotation of the brush drive gear  82  induces rotation of the clutch pulley  90 . During normal operating conditions, the spring  86  forces the clutch  88  into mating contact with the clutch pulley  90 , whereby the first and second ramped surfaces  92 ,  94  mate and engage. As a result, the clutch  88  rotates with the clutch pulley  90 , and the brush dowel  50  rotates with the clutch  88 . Consequently, the bristles  52  agitate the surface to be cleaned through the agitator aperture  46 . When rotation of the brush dowel  50  is prevented, such as when an object becomes caught in the bristles  52  and thereby prevents movement of the brush dowel  50 , the first ramped surface  92  of the clutch  88  cannot rotate. At the same time, the brush drive gear  82  and the drive belt  84  continue to rotate the clutch pulley  90  and the second ramped surface  94 , which rides over the non-rotating first ramped surface  92 . Consequently, the first and second ramped surfaces  92 ,  94  disengage, and the clutch pulley  90  pushes the clutch  88  axially against the bias of the spring  86  towards the brush dowel  50 . In other words, the clutch pulley  90  continues to rotate with the drive belt  84  while the clutch  88  slips relative to the clutch pulley  90 . Because the clutch  88  does not rotate, the clutch  88  does not impart a rotational force to the brush dowel  50 . This action prevents damage to the brush motor  58 , the brush drive belt  84 , and the brush dowel  50 . 
     Referring now to  FIGS. 3 ,  7 , and  8 , the powered sweeper  10  further comprises corner brush assemblies  68  mounted in corner brush drive cavities  76  formed between the lower housing  24  and the upper housing  26  along the sides of the foot assembly  14 . Each corner agitator assembly  68  comprises a corner brush pulley  74  detachably mounted to a corner brush support  70  having a plurality of bristles  72  attached thereto. The bristles  72  extend radially from the corner brush support  70  and towards the surface to be cleaned to agitate the surface to be cleaned. Each corner agitator assembly  68  is rotatably mounted on a corner brush bearing  104  projecting upward from the lower housing  24  in a forward end of the respective brush drive cavity  76 . In particular, the corner brush support  70  and the corresponding corner brush pulley  74  are brought into contact from opposite sides of the corner brush bearing  104  and snap-fit together. Alternatively, the corner brush support  70  and the corresponding corner brush pulley  74  can be joined together by a welding process or separate mechanical fasteners. The corner brush supports  70  and the corner brush pulleys  74  are joined such that rotation of the latter induces rotation of the former. 
     With continued reference to  FIGS. 3 and 7 , each wheel  30  is mounted to a wheel axle  79  that extends into the foot assembly  14  between wheel axle bearings  98  of the upper and lower housings  26 ,  24 . Each wheel axle  79  supports a wheel pulley  78  inside the foot assembly  14  such that rotation of the wheels  30  induces rotation of the wheel pulleys  78 . A pair of corner brush belts  80 , each one wrapped around one of the wheel pulleys  78  and one of the corner brush pulleys  74 , transfers rotation movement of the wheel pulleys  78  into rotational movement of the corner brush supports  70  about a generally vertical axis. The corner brush belts  80  reside in and are movable within the corner brush cavities  76 . 
     Referring to  FIGS. 8 and 9A , the lower housing  24  supports a ramp assembly  106  located laterally along a rearward edge of the agitator aperture  46 . The ramp assembly  106  comprises a retractable ramp  108  and a fixed ramp  110 . The retractable ramp  108 , which is preferably made of a resilient material, is moveably mounted to the lower housing  24  by a pair of guides (not shown) integrally molded to side walls of the lower  24  housing on both sides of the agitator aperture  46  so that the retractable ramp  108  floats within the guides. In a preferred embodiment, both the retractable ramp  108  and the fixed ramp  110  are generally planar. In an alternate embodiment, which is illustrated in  FIG. 9B , both the fixed ramp  110  and the retractable ramp  108  are arcuately shaped. In operation, the retractable ramp  108  is in constant contact with the surface to be cleaned and moves within the guides to maintain contact, regardless of surface conditions or the direction of travel of the sweeper  10 . However, the retractable ramp  108  is adapted to collect dirt and debris when the sweeper moves in a forward direction (to the left in  FIGS. 9A and 9B ) and merely glides over the surface to be cleaned when the sweeper moves in a reverse direction. 
     In an alternate embodiment, the wheels  30  are coupled to the retractable ramp  108  via a commonly known geared or belt and pulley arrangement to urge or bias the retractable ramp  108  towards the surface to be cleaned to a first, extended position when the powered sweeper  10  moves in a forward direction whereby the agitator aperture  46  leads the dust bin  32 . In the first position, the retractable ramp  108  contacts the surface to be cleaned and helps to collect debris in the vicinity of the agitator aperture  46 . When the powered sweeper  10  moves in a rearward direction with the dust bin  32  leading the agitator aperture  46 , the retractable ramp  108  rides up along the fixed ramp  110  to a second, retracted position, wherein the retractable ramp  108  is spaced from the surface to be cleaned so that debris can pass under the retractable ramp  108  and into the agitator aperture  46 . 
     Referring now to  FIG. 8 , the lower housing  24  includes an arcuate pivot cradle  100  centrally located in a rearward portion thereof to rotatably receive the lower handle assembly  18 . A pivot detent ramp  102  extending longitudinally along the pivot cradle  100  divides the pivot cradle  100  into an arcuate forward portion  100 A and an arcuate rearward portion  100 B. The pivot cradle  100  in the lower housing  24  is aligned with the pivot recess  38  in the upper housing  26  for mounting the handle assembly  12  to the foot assembly  14 . 
     As shown in  FIGS. 10 and 11 , the lower handle assembly  18  further comprises a lower section  111  oriented at an obtuse angle relative to the grip  20 , and the lower section  111  terminates in a generally cylindrical pivot  112  oriented orthogonal to the lower section  111 . The pivot  112  is shaped such that it can be seated in and rotate relative to the pivot cradle  100 . Further, the pivot  112  has a cavity  115  that is generally coaxial with the lower section  111  and houses a detent spring  117 . The detent spring  117  abuts the end of the cavity  115  at one end and a detent roller  114  at an opposite end. The detent roller  114  is affixed to a detent axle  116  that resides in a central longitudinal slot through the detent roller  114 . The detent axle  116 , which defines a generally horizontal rotation axis for the detent roller  114 , is captured in a corresponding slot (not shown) in the pivot  112  to rotatably mount the detent roller  114  to the lower handle assembly  18 . The detent spring  117  biases the detent roller  114  in a direction out of the cavity  115  and towards the pivot cradle  100 . The pivot axle  116  limits movement of the detent roller  114  out of the cavity  115 ; therefore, only a portion of the detent roller  114  projects from the pivot  112 . At least one of the detent axle  116  and the corresponding slot in the pivot  112  is designed to accommodate retraction of the detent roller  114  into the cavity  115  when an external force is applied to the detent roller  114  against the bias of the detent spring  117 . 
     Referring now to  FIGS. 11 and 12 , the pivot  112  sits on the pivot cradle  100 , and the lower section  111  extends upward through the pivot recess  38  in the upper housing  26 . As shown in  FIG. 11 , when the handle assembly  12  is in the upright position, the detent roller  114  is located in the rearward portion  100 B of the pivot cradle  100  and is held therein by the detent ramp  102 . The detent ramp  102  abuts the detent roller  114  to prevent the detent roller  114  from moving into the forward portion  100 A and thereby maintain the lower handle assembly  18  in the vertical position. When the handle assembly  12  is in the upright position, the obtuse angle between the lower section  111  and the grip  20  locates the handle assembly  12  vertically near the middle of the foot assembly  14 . In addition, a forward surface of the lower section  111  makes contact with a forward portion of the pivot recess  38  and acts as a mechanical stop to prevent the handle from moving past the upright position towards the forward position. While the geometry of the obtuse angle on the lower handle assembly  18  provides inherent stability to the sweeper  10  with the handle assembly  12  in the upright position, the detent roller  114  when seated in the rearward portion  100 B adds structural rigidity and provides the user with an audible and tactile indication that the handle assembly  12  is properly positioned in the upright position. 
     To move the lower handle assembly  18  to the horizontal position from the vertical position, the user rotates the grip  20  of the lower handle assembly  18  rearward. As a result of this force applied by the user, the detent roller  114  rides up the detent ramp  102 , which pushes the detent roller  114  into the cavity  115  against the bias of the detent spring  117  while the detent pin  116  moves, bends, or otherwise accommodates movement of the detent roller  114 . Because the detent roller  114  retracts into the cavity  115 , the pivot  112  can rotate clockwise, relative to the orientation of  FIGS. 11 and 12 , to a position where the detent roller  114  is located in the forward portion  100 A of the pivot cradle  100 . After the detent roller  114  passes the detent ramp  102 , the detent spring  117  returns the detent roller  114  to the position where it partially protrudes from the pivot  112  and the lower handle assembly  18  can rotate along the forward portion  100 A of the pivot cradle  100 . The lower handle assembly  18  can be rotated to any position desired by the user, including the horizontal position shown in  FIG. 12 . The obtuse angle between the lower section  111  and the lower grip  20  provides an offset whereby clearance for the user&#39;s hand is provided between the lower grip  20  and the surface to be cleaned when the lower handle assembly  18  is in the horizontal position. Preferably, the pivot cradle  100  or at least one of the upper and lower housings  26 ,  24  includes a stop to prevent movement of the lower handle assembly  18  beyond the horizontal position. To return the lower handle assembly  18  to the vertical position, the user rotates the grip  20  forward so that the detent roller  114  abuts the detent ramp  102  and retracts into the cavity  115  as described above so that the detent roller  114  can pass the detent ramp  102 , which thereafter retains the detent roller  114  in the rearward portion  100 B of the pivot cradle  100 . 
     An exemplary description of the operation of the powered sweeper  10  follows. It will be appreciated by one of ordinary skill that the operation can proceed in any logical order and is not limited to the sequence presented below. The following description is for illustrative purposes only and is not intended to limit the scope of the invention in any manner. 
     In operation, the user connects the electrical power transformer and power cord to the charger jack  44  to charge the battery pack  62 . Once the battery pack  62  is sufficiently charged, the electrical power transformer and power cord is disconnected from the charging jack  44 . The handle assembly  12 , with the upper handle segments  16  (if the powered sweeper is used in the upright mode) or without the upper handle segments  16  (if the powered sweeper is used in the hand-held mode), is rotated in a generally rearward direction from the vertical storage position in the manner described above so that the handle assembly  12  is oriented at an acute angle relative to the surface to be cleaned. The user then depresses the switch cover  45  to close the electrical switch  66  and establish electrical communication between the battery pack  62  and the brush motor  58 . The brush motor  58  rotates the main shaft  59  and the brush drive gear  82 , which thereby turns the brush drive belt  84 . The brush drive belt  84  induces rotation of the clutch gear assembly  56  and, ultimately, spins the brush dowel  50  and the bristles  52  in the agitator aperture  46 . The dust bin inlet aperture  130  is in fluid communication with the agitator aperture  46 , and the agitator assembly  48  throws debris from the surface to be cleaned rearwardly and upwardly along the ramp assembly  106  and into the dust bin  32  through the dust bin inlet aperture  130 . The arcuate wall section  126  directs the debris to either side of the dust chamber  118 , and the debris collects on the floor  120  of the dust bin  32 . Further, as the user moves the foot assembly  14  in a forward or rearward direction, the wheels  30  rotate the wheel axles  79  and wheel pulleys  78 , which move the corner brush belts  80 . The corner brush belts  80  induce rotation of the corner brush assemblies  68 , and the corner brush bristles  72  rotate to throw debris towards and in front of the foot assembly  14 , where it can be picked up by the agitator assembly  48  as previously discussed. When sweeping is complete, the user depresses the switch cover  45  to open the electrical switch  66  and stop current flow to the brush motor  58  from the battery pack  62 . Rotation of the agitator assembly  48  ceases and the user pivots the lower handle assembly  18  to the vertical storage position wherein the detent roller  114  resides in the rearward portion  100 B of the pivot cradle  100  behind the detent ramp  102  as described above. 
     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 within the foregoing disclose and drawings without departing from the spirit of the invention which is embodied in the appended claims.