A rotary push broom provides a geometry between the centerline of the broom's wheels and the centerline of the broom's cylindrical brush that allows the vertical height of the cylindrical brush relative to that of the wheels to be adjusted as the frame rotates. The broom includes a support stand that allows the broom to be stored in a way that does not put the broom's weight on the brush. The broom also includes a ratchet gear system so that the broom rotates along with the wheels when the broom is operated in a forward sweeping direction and spins independent of the wheels when the broom is operated in a rearward direction. The gear system should be arranged so that the cylindrical brush rotates slower than the wheels in the sweeping direction. The support stand can be integrated with an endplate that accommodates the wheel connection and ratchet gear system.

BACKGROUND OF THE INVENTION

The primary function of a push broom is to sweep large areas. One of the problems with existing push broom designs is that debris is left behind after the broom makes a single pass in the forward sweeping direction. To sweep up the left-behind debris, a user must make multiple passes with the broom, lifting the broom in a circular type motion, pulling it back toward the user, and re-sweeping much if not all of the same area as was originally swept.

Over the years, alternative sweeping devices have been developed to allow users to sweep large areas more efficiently. Many of the alternative sweeping devices require external power or incorporate bins for capturing debris, neither of which is desirable in a lot of cases.

One example of a manually operated rotary broom is disclosed in U.S. Pat. No. 4,864,674 to Hamilton. The broom includes a removable disc with blades and a locking arrangement that, depending in part on the angle of the handle, locks and unlocks to provide a standard push broom mode and a continuous rotation pick-up (dustpan) mode. The dustpan mode deposits debris in a cylinder housed between the wheels. The disc and wheels share a common centerline.

Another example of a manually operated rotary broom is disclosed in U.S. Pat. No. 8,156,596 B2 to Rose. The broom includes a pre-adjusted cylindrical brush height as well as gearing that permits the cylindrical brush to rotate at a faster rotational speed than, and in a opposite direction to, the wheels but not disengage from the wheels. When the broom is operated in the forward sweeping direction the cylindrical brush sweeps debris ahead of itself, away from the user. However, faster rotational speed can cause debris to be thrown too far ahead of the broom and fine debris to rotate back around the brush and be left behind by the broom. When the broom is pulled back toward the user, the brush continues to rotate and now sweeps some of the debris back toward the user. In the cylindrical brush's highest position, the centerline of the wheels and that of the brush are in the same horizontal plane with the brush centerline leading the wheels. In the brush's lowest position, the centerline of the brush is below that of the wheels.

SUMMARY OF THE INVENTION

A rotary push broom made according to this invention provides a geometry, rotational speed and storage means that make it very different from other manually operated rotary brooms. The geometry allows the vertical height of the cylindrical brush relative to that of the wheels (and therefore the surface to be swept) to be adjusted simply by rotating the frame with the handle while the broom is in use. An alternate embodiment keeps the handle in the same position but relies on a hinged connection to the broom's frame to rotate the frame.

The storage means, preferably in the form of an end plate that serves as support stand or “kickstand,” allows the broom to be stored in a way that does not put the broom's weight on the brush. This eliminates the creation of a flat spot which leads to uneven rotation and reduced sweeping performance, as well as premature replacement of the brush. The support stand could also be separate from the end plate and put elsewhere on the frame to serve the same kickstand function. The stand could also be in the form of a rod which extends from the middle of the frame.

In one embodiment of the rotary push broom, the broom includes a pair of wheels arranged in a frame along a same centerline and a cylindrical brush arranged in the frame along a centerline different than the centerline of the pair of wheels. The centerline of the cylindrical brush is arranged such that an angular rotation of the frame of the rotary push broom changes a vertical height of the cylindrical brush relative to the centerline of the wheels. For example, the centerline of the cylindrical brush can be rearward of the wheels and in the same horizontal plane as the wheel centerline.

A ratchet gearing system is arranged to reduce a rotational speed of the cylindrical brush relative to that of the pair of wheels when the pair of wheels is rotating in a forward (sweeping) direction away from a user but allows the cylindrical brush to rotate independent of the pair of wheels when the pair of wheels is rotating in a rearward direction.

The ratchet gearing system can include a first gear connected to a wheel in the pair of wheels and a second gear mated to the first gear and connected to a drive shaft of the cylindrical brush. Preferably, both wheels have this first and second gear combination. The second gear preferably has at least one cavity which receives the drive shaft and has a curved surface and an opposing flat surface. In this arrangement, the drive shaft has a key arranged to engage the opposing flat surface when the pair of wheels is rotating in the forward direction and engage the curved surface when the pair of wheels is rotating in the rearward direction.

The end plate can be arranged between one of the wheels and an opposing end of the cylindrical brush. When intended for use as a kickstand, the end plate should have a flat bottom end and extends forward of the wheels to maintain the rotary push broom in a free standing state when not in use (e.g., the handle of the broom in a 12 o'clock position).

The end plate when configured as a kickstand should be arranged so that when the frame is titled in a rearward direction the bottom end of the plate does not extend past—and is preferably at a vertical height above—the lower surface brush in contact with the surface being swept (i.e. above ground level and not even with the wheels). When in the free-standing state the bristles of the brush lying opposite the floor surface should be at a vertical height above that of the bottom end of the endplate so that no weight is placed on the bristles.

The end plate with or without the integrated support stand can include two openings, with one opening co-axial to the centerline of the pair of wheels and the other opening co-axial to the centerline of the cylindrical brush, to accommodate the wheel connection and the ratchet gearing system.

In another preferred embodiment of the rotary push broom, the broom includes a pair of wheels arranged in a frame along a same centerline and a cylindrical brush arranged in the frame along a centerline different than and rearward of the centerline of the pair of wheels. A ratchet gearing system is arranged to rotate the cylindrical brush when the pair of wheels is rotating in a forward direction and cause the cylindrical brush to rotate independent of the pair of wheels when the pair of wheels is rotating in a rearward direction. At least one support stand, which could be in the form of an endplate, is arranged between one of the wheels in the pair of wheels and an opposing respective end of the cylindrical brush. Again, the stand can be separate from the end plate and placed elsewhere on the frame. The ratchet gearing system can be arranged such that a rotational speed of the cylindrical brush is slower than that of the wheels in the forward direction. The centerline of the cylindrical brush should be arranged such that an angular rotation of the frame changes a vertical height of the cylindrical brush relative to the centerline of the wheels.

The at least one end plate, and preferably both, can be arranged to connect one of the wheels to the frame and accommodate at least a portion of the ratchet gearing system. A crossbar can connect the kickstand to the frame.

Objectives of this invention include providing a manually operated rotary push broom that (1) rotates at a slower rotation than that of the wheels when the broom is moving in a forward direction; (2) has a free-spinning state independent of the wheels when the broom is moving in a rearward direction; (3) can adjust the height of the cylindrical brush as the broom is being used; and (4) maintains the broom in a free-standing state and in such a way that no weight is placed on the bristles of the cylindrical brush.

ELEMENTS AND NUMBERING USED IN THE DRAWINGS

8Frame10Centerline/axis of rotation of wheel2012End plate with integrated support stand14Crossbar16Handle connector18Cylindrical brush20Wheel22Handle24Rotary push broom26Brush bristle28Ratchet gear system30Lock ring32Brush or second gear34Drive key36Gear/drive shaft38Bushing or bearing40Wheel axle42Direction of wheel rotation when broom is in sweeping (forward) direction44Direction of brush gear rotation (and therefore brush18) when broom is in sweeping direction46Wheel or first gear4648Dust guard50Centerline/axis of rotation of cylindrical brush1852Cavity located on inside of3654Curved side of5256Flat side of52opposite5458Flat bottom side of1260Arcuate-shaped top side of1262Forward end of1264Rearward end of1266First opening68Second opening

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, a preferred embodiment of a rotary push broom24made according to this invention includes a ratchet gear system28that provides rotational force to the cylindrical brush18in the push direction but disengages the brush18in the opposite direction and an end plate12that serves as support plate or kickstand that permits the broom24to be stowed in a free-standing, upright position such that none of the brush bristles26contact the ground when stowed.

Broom24preferably does not make use of a wheel axle that runs wheel-to-wheel or through the brush, nor does it make use of an external frame structure. Instead, a crossbar14connects opposing end plates12to one another to form a frame8. A handle connector16on crossbar14connects handle22to the crossbar14. Each end plate12is preferably arranged so that when the handle22is in the 12 o'clock (upright) position, the end plates12maintain the broom24in the upright position. A forward end62of the end plate12preferably extends past the wheels20so that greater stability is provided to the broom24when being stowed.

One end plate with integrated support stand12may be used but two are preferred. Alternatively, the support stand itself could be separate from the end plate12and connected elsewhere to the frame (e.g., in the middle of the frame as a rod or its equivalent extending forward of the frame). If only one end plate with integrated support stand12is used, the other end plate12must be replaced by an equivalent structure for performing the other functions of the plate12, such as connecting itself to crossbar14to create a frame8and providing means to connect the wheel20and accommodate the ratchet gear system28for the cylindrical brush18.

Each end plate12, for purpose of serving as the support stand, is preferably tear drop-shaped having a flat bottom side58, an arcuate-shaped top side60, and a semi-circular shaped rearward end64. The end plate12includes two openings66,68which accommodate wheel connections and the ratchet gear system28. The first opening66is arranged coaxial with the centerline10of wheel20. At least one of the end plates12is arranged to accommodate the ratchet gear system28.

Each wheel20can be connected to its respective end plate12by a wheel axle40that passes through the opening66and the wheel20and receives a locking ring30(seeFIG. 2). Wheel axle40preferably does not extend wheel-to-wheel or through the brush18so that, as described below, the brush centerline50can be placed in various relationships to the wheel centerline10.

During operation, the wheels20contact the surface to be swept and rotate due to friction. Preferably, wheels20are located outside of cylindrical brush18but may also be located within the interior of the brush18so that portions of the brush18lie outside of the wheels20. When handle24is moved in a rearward (user) direction, at least a portion of the bottom side58, and preferably all of the bottom side58, of the end plate12raises up so that the bottom side58is above that of the lower or contacting surface of the wheels20. For example, in one preferred embodiment, when the cylindrical brush18is engaged with the floor surface, the bottom side58of the plate12is about 3″ above the floor surface with the rearward end64about ⅛″ above the floor surface. This height changes as the frame8rotates to different angular orientations.

The second opening68is offset from the first opening62so that it is coaxial with the centerline50of the cylindrical brush18. A bushing or bearing38resides within the opening68and receives a drive shaft36for the cylindrical brush18. When rotary broom24is operated in the forward, sweeping direction, the leading end of brush bristles26trail behind the leading surface of the wheels20. Alternatively, the brush18could be sized or arranged such that the bristles26lie ahead of the leading surface of the wheels20.

The centerline50of the cylindrical brush18is offset from and behind the centerline10of the wheels20. Preferably, the two centerlines10,50lie in the same horizontal plane. The two centerlines10,50could be in other relationships to one another so long as each is separated by a distance which accommodates the ratchet gear system28and provides the desired rotational relationship between the wheels20and the cylindrical brush18. For example, the brush centerline50could be directly above the wheel centerline10and approach the floor surface as the frame8rotates downward toward the surface.

Because the centerline50of the cylindrical brush18is different than the centerline10of the wheels20, and is rearward of the centerline10, as the handle22moves to different angular positions during use, the brush bristles26vary in their relationship to the surface being swept. In other words, the vertical height of the cylindrical brush18relative to that of the wheels20changes. For example, the centerline50can be arranged such that a certain angular orientation of handle22(e.g., 45° from horizontal) rotates the frame8and places the centerline50at a distance from the surface to be swept which equals that of the length of the bristles26, with smaller angles from horizontal causing an interference condition between the surface and bristles26(see e.g.FIG. 3) and larger angles providing no contact with the surface whatsoever.

Each wheel20includes a wheel or first gear46that mates to a brush or second gear32. The preferred gearing relationship is such that the cylindrical brush18rotates at a slower speed than do the wheels20. This is opposite the trend in manual rotary brush design, which equates faster brush rotation with more effective sweeping and cleaning action. A series of experiments conducted by the inventor showed that slowing the speed of the brush made an unexpected and surprising difference in containing debris ahead of the brush, reducing the amount of dust, and overall cleaning effectiveness (and therefore efficiency) of the broom24.

Experiments conducted by the inventor show that a slower-than-wheel brush turn provides better sweeping performance than a faster-than-wheel brush turn (see Table 1 below). Preferably, the cylindrical brush18rotates slower than the wheels20and, more preferably, at no greater than 75% the rotational speed of the wheels20. At this speed, the broom24left only 10% of the debris left behind by a push broom after a single pass under the same test conditions. Also, preferably the brush18rotates no slower than 35% of the rotational speed of the wheels20. This ratio can be manipulated by changing wheel diameter and brush diameter and the gearing32,46to determine the best speed for the surface to be swept and type of debris being swept. The rotation of the brush18can be in a range of 30 to 90% of that of the wheels20.

Brush gear32provides ratchet-type performance to the cylindrical brush18. The gear32preferably includes three identical and equally spaced-apart cavities52on the inside of the gear32. Each cavity52is curved on one side54and flat on the other side56. As gear32rotates in the free-spinning direction (opposite that of direction44, meaning the wheels20are rotating opposite that of direction42), a drive key34on drive shaft36is engaged by the curved side54of each cavity56, which pushes the drive key34back-and-forth through a slot in drive shaft36. The rotary brush18, therefore, rotates independent of the wheels20when the wheels are rotating opposite the forward direction42.

As gear32rotates in the “drive” or forward (push or sweep) direction44—meaning the wheels20are rotating in their forward direction42, the drive key34is engaged by the flat portion56of the cavity52and force transmitted to the key34rotates the drive shaft36. The rotary brush18rotates dependent on the wheels20, with the brush18rotation44being opposite that of the wheels20and slower than that of the wheels20.

Other designs may be used for ratchet gear system28provided those other designs provide rotation of the brush18in the forward direction and free spinning in the opposite direction.

A foldable guard48may be added to the broom24to stop or knock down debris as it moves away and ahead of the brush18. Guard48may be made from canvas or other wear resistant material. Alternatively, the broom24can be free of any capturing device or receptacle.

While preferred embodiments have been described, not all possible embodiments of the invention have been. The following claims define the scope of the invention and include the full range of equivalency to which the specific requirements of the claims are entitled.