ABRASIVE DEVICE FOR FLOOR SCRUBBING, CLEANING AND/OR POLISHING

TECHNICAL FIELD

This application relates generally to abrasive deep cleaning, restoration, honing and/or polishing of concrete floors and, more specifically, to an abrasive device for such purpose.

BACKGROUND

Concrete is traditionally used for floors in both residential and commercial applications in view of its robustness and economic benefits. Depending upon the circumstances, the concrete may be left unfinished, partially finished, or completely finished with, e.g., a high gloss decorative coating.

In warehouses, factories, etc., concrete floors are cleaned and/or polished, by rotary driven scrubbing, cleaning, and/or polishing machines that employ brushes positioned on the underside of the machinery whereby the machinery traverses the floor to provide a clean surface. Generally, efficiency in scrubbing, cleaning, and/or polishing operations is desirable, in any or all of, e.g., the varieties of brushes needed (e.g., different grit values), the number of passes over the floor required, the cleaning area of the brushes, the uniformity of the performance of the brushes, and the durability of the brushes.

Rotary driven machines for scrubbing, cleaning, and/or polishing concrete floors have numerous configurations and, specifically, can have varied configurations of the axis rotation of the brush or cleaning element. Machines can have disc-shaped cleaning elements rotated about the axis of the disc with the axis perpendicular to the floor, with the face of the disc having the brush, abrasive, etc. (aka disc style cleaning machines). Machines can also have cleaning elements with the brush, abrasive, etc. on the outside surface of a generally cylinder shape, with the machine driving the element about the cylindrical axis and with that axis generally parallel to the floor (aka cylinder style cleaning machines).

In the past, for the purpose of achieving high end finishing and polishing, the disc style cleaning machines have been utilized in combination with specific abrasive structures having refined abrasive properties. By way of example, U.S. Pat. No. 9,796,067 discloses a brush assembly in which a plurality of abrasive polymer strips extend downwardly from a pad, with the strips engaged in radially extending slots of the pad. This configuration has been employed commercially with a meaningful level of commercial success and acceptance.

FIGS. 9 and 10 of U.S. Pat. No. 9,796,067 also disclose a brush assembly for use with a cylindrical style cleaning machine, where elongated abrasive brush strips extend radially outward from the outer cylindrical surface of a cylinder, with the strips running axially along a length of the cylinder, parallel to a central rotation axis of the cylinder. However, the dynamics of cylindrical abrasion, which has intermittent contact of the abrasive brushes with the floor surface, are significantly different and less well understood than disc abrasion, which has continuous wiping contact of the abrasive brushes with the floor surface. While a typical use pattern and dynamics of a disc style machine requires the abrasive brushes to undergo repeated full bending and straightening cycles less than fifty times per week (because the brushes tend to be in continuous contact with the floor during machine operation), the typical use pattern and dynamics of a cylindrical style machine will require the abrasive brushes to undergo repeated bending and straightening cycles more than three million times per week (because the brushes move into and out of contact with the floor multiple times per second during machine operation), and therefore the abrasive brushes must have substantially greater ability to prevent fatigue failure. A cylindrical brush assembly of the type disclosed in U.S. Pat. No. 9,796,067, employing abrasive brush strips of the type disclosed in the patent, result in both excessive noise during operation and excessive scratching of the concrete floor surface. Therefore, to date, cylindrical abrasive brush configurations have not been commercially implemented with any degree of success, particularly for the purpose of deep cleaning (removal of foreign material from the floor surface), restoration (flattening of the floor surface to prepare for polish and hone), honing and/or polishing of concrete floors in a manner that advantageously closes the pores of the concrete.

Accordingly, it would be desirable to provide cylindrical abrading assemblies that can be used in cylinder style cleaning machines, on an effective basis, to remove surface material and produce a high end, commercially acceptable polish finish.

SUMMARY

In one aspect, an abrasive device for use on concrete floors includes an elongated body having a first end, a second end and an outwardly facing body surface extending about a body axis and between the first end and the second end, the elongated body configured to engage a rotary cleaning machine and be driven about the body axis. A plurality of blades extend, at least in part, radially outwardly from the outwardly facing body surface, each blade including a blade abrasive part extending from a distal end of the blade toward the elongated body. Each blade of the plurality of blades includes a first axial blade end located toward the first end of the elongated body and a second axial blade end located toward the second end of elongated body. Each blade of the plurality of blades runs in an orientation that is angularly offset from the body axis between the first axial blade end and the second axial blade end.

In another aspect, an abrasive device for use on concrete floors includes an elongated body having a first end, a second end and an outwardly facing body surface extending about a body axis and between the first end and the second end, the elongated body configured to engage a rotary cleaning machine and be driven about the body axis. A plurality of blades extend, at least in part, radially outwardly from the outwardly facing body surface, each blade including a blade abrasive part extending from a distal end of the blade toward the elongated body. Each blade of the plurality of blades includes a first axial blade end located toward the first end of the elongated body and a second axial blade end located toward the second end of elongated body. The elongated body includes a plurality of channels opening to the outwardly facing body surface, wherein each channel receives a radially inward end of a respective one of the blades. Each channel includes a first channel axial end that is open to the first end of the elongated body, and a second channel axial end that is spaced apart from the second end of the elongated body, such that an end wall of the second channel axial end prevents blade movement axially toward the second end of the elongated body.

In a further aspect, an abrasive device for use on concrete floors includes an elongated body having a first end, a second end and an outwardly facing body surface extending about a body axis and between the first end and the second end, the elongated body configured to engage a rotary cleaning machine and be driven about the body axis. A plurality of blades extending, at least in part, radially outwardly from the outwardly facing body surface of the body, each blade including a blade abrasive part extending from a distal end of the blade toward the elongated body. Each blade of the plurality of blades includes a first axial blade end located toward the first end of the elongated body and a second axial blade end located toward the second end of elongated body. For at least a first blade of the plurality of blades, the blade abrasive part is joined to a blade non-abrasive retaining part of the blade, wherein the blade abrasive part comprises a first thermoplastic and at least one abrasive grit material, the first thermoplastic having a first durometer, the blade non-abrasive retaining part comprising a second thermoplastic having a second durometer, wherein the first durometer is lower than the second durometer.

In still another aspect, a blade for use in an abrasive device for use on concrete floors includes a distal end, a retaining end, a blade abrasive part and an blade non-abrasive retaining part, the blade abrasive part including the distal end and extending toward the retaining end, the blade non-abrasive retaining part including the retaining end and extending toward the distal end. The blade abrasive part is joined to the blade non-abrasive retaining part, wherein the blade abrasive part comprises a first thermoplastic and at least one abrasive grit material, the first thermoplastic having a first durometer, the blade non-abrasive retaining part comprising a second thermoplastic having a second durometer, wherein the first durometer is lower than the second durometer.

In still another aspect, an abrasive device includes an elongated body having a first end, a second end and an outwardly facing body surface extending about a body axis and between the first end and the second end, the elongated body configured to engage a rotary cleaning machine and be driven about the body axis. A plurality of discrete abrasive structures are positioned on the outwardly facing body surface, each abrasive structure having a plurality of abrasive projections extending, at least in part, radially outwardly from the outwardly facing body surface. Each abrasive structure comprises a molded unit including a base that abuts the outwardly facing body surface and the plurality of abrasive projections extend from the base. The plurality of abrasive structures are collectively positioned on the outwardly facing body surface such that, for each rotational position of the elongated body about the body axis when the abrasive device is adjacent a floor surface with the body axis substantially parallel to the floor surface, at least part of one of the abrasive projections will be in contact with the floor surface

The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 show perspective views of one embodiment of an abrasive device;

FIG. 3 shows an axial end view of the abrasive device;

FIG. 4 shows an axial end view with only one of the blades;

FIG. 5 shows another perspective view;

FIG. 6 shows a elevation view;

FIG. 7 shows a partial perspective view of an end of the abrasive device;

FIG. 7A shows an alternative configuration of a blade profile in the channel;

FIG. 7B shows an alternative configuration of a blade with a notched end;

FIG. 8 shows a segment of an exemplary blade;

FIG. 8A shows a segment of the blade with thicker joining region;

FIG. 9 shows a perspective view of the body of the abrasive device;

FIG. 10 shows a perspective view of a blade of the abrasive device;

FIGS. 11, 12, 13 and 14 show, respectively, perspective, elevation, axial end (all blades) and axial end (single blade) views of an alternative embodiment of an abrasive device;

FIGS. 15, 16, 17 and 18 show, respectively, perspective, elevation, axial end (all blades) and axial end (single blade) views of another alternative embodiment of an abrasive device;

FIGS. 19, 20 and 21 show, respectively, perspective, perspective and cross-section views of another alternative embodiment of an abrasive device;

FIG. 22 shows a cross-section of an abrasive device;

FIGS. 23 and 24 show partial perspective views or alternative attachment of blades into body channels;

FIG. 25 shows a partial perspective of an end cap for axially retaining blades;

FIG. 26 shows an alternative embodiment of channel length on a body of an abrasive device;

FIG. 27 shows another end cap configuration for axially retaining blades;

FIG. 28 shows a perspective view of an abrasive device having tapered blades;

FIG. 29 shows an enlarged partial perspective of the tapered blades;

FIG. 29A shows an exemplary taper profile;

FIG. 29B shows an alternative embodiment of a blade profile with a lateral end slot;

FIG. 30 shows a perspective view of an abrasive device with a multi-piece body;

FIG. 31 shows an enlarged perspective view of a joint region of the multipiece body;

FIGS. 32 and 33 show partial perspective views of an abrasive device embodiment in which a series of clamp plates are attached to the body to retain the blades;

FIG. 34 shows a partial perspective of an abrasive device embodiment in which the blade is retained by wire form retainers;

FIG. 35 shows a partial perspective of an abrasive device embodiment in which each blade is substantially L-shaped;

FIG. 36 shows a partial perspective an end cap system for adapting the body to different machines;

FIGS. 37-39 show perspective views of another embodiment of an abrasive device;

FIGS. 40-42 show perspective views of another embodiment of an abrasive device;

FIG. 43 shows a perspective view of an abrasive device embodiment incorporating brush tufts;

FIGS. 44-46 show an exemplary blade in which the blade parts are connected by fasteners;

FIGS. 47-49 show an exemplary blade profile that is thicker in the joining region of the blade parts;

FIGS. 50-51 show perspective views of an axial blade retention configuration;

FIG. 52 shows an alternative axial blade retention configuration;

FIGS. 53-60 show an alternative embodiment of an abrasive device including brush tufts;

FIGS. 61 and 62 show exemplary alternative profiles of the elongated body for the abrasive devices;

FIG. 63 shows an alternative body and channel configuration for abrasive devices;

FIG. 64 shows an exemplary cleaning machine incorporating one or more abrasive devices;

FIGS. 65-69 show another embodiment of an abrasive device having a wrapped abrasive structure;

FIGS. 70-73 show another embodiment of an abrasive device having multiple wrapped abrasive structures; and

FIGS. 74-77 show another embodiment of an abrasive device having multiple abrasive structures.

DETAILED DESCRIPTION

Utilizing ordinary floor scrubbing, cleaning, and/or polishing machines for more applications provides inherent efficiencies. Abrasive brush devices have been developed to be compatible with typical floor cleaning and polishing machines but provide new functionality. As forces on a brush increase with the abrasive properties, and as material is removed with abrasion, greater compatibility and efficiency of operation is provided with cylindrical brushes that account, independent of the cleaning machine, for those new aspects of operation attendant to the new functionality.

Referring to FIGS. 1-10, an abrasive device 10 for use on concrete floors includes an elongated body, here a substantially cylindrical body 12 having a first end 14, a second end 16 and an outwardly facing surface, here a substantially cylindrical outer surface 18, extending about a central body axis 20 and between the first end 14 and the second end 16. The substantially cylindrical body 12 is configured (e.g., with a series of internal ribs 22 for making a spline type driving connection) to engage a rotary cleaning machine and be driven about the body axis 20 while the body axis is in a substantially horizontal orientation relative to a concrete floor surface. Such an abrasive device 10 could be employed include machines available from Tennant®, such as the Tennant T5700 adapted for cylindrical brushes, but use in other machine types is also possible.

In the abrasive device 10, a plurality of blades 24 extend, at least in part, radially outwardly from the substantially cylindrical outer surface 18. Here, at each axial location along a length of each blade, the blade extends substantially radially relative to the body axis 20, but variations in which the blades are purposely configured to extend in a direction that is offset from radial (e.g., by 5 degrees or 10 degrees or more) are possible. However, variations in which it is primarily the distal end edge of the blade making contact with the floor surface, as opposed to the leading face of the blade, have demonstrated better performance.

Each blade 24 includes a blade abrasive part 24a extending from a distal end 24b of the blade toward the substantially cylindrical body 12. Each blade 24 includes a first axial blade end 24c located toward the first end 14 of the substantially cylindrical body 12 and a second axial blade end 24d located toward the second end 16 of substantially cylindrical body 12 (i.e., first axial blade end 24c is closer to first end 14 than second axial blade end 24d, and second axial blade end 24d is closer to second end 16 than first axial blade end 24c). Notably, each blade 24 runs in an orientation that is angularly offset from parallel to the body axis, here in a substantially helical orientation (e.g., with a constant helix angle or varying helix angle), between the first axial blade end and the second axial blade end. Testing has established that this configuration provides superior performance, as to noise level, deep cleaning and restoration, and surface finish, as compared to configurations in which the blades extend linearly, in parallel with the body axis 20.

Here, each blade 24 substantially axially spans an axial length L18 of the substantially cylindrical outer surface 18 between the first end and the second end of the substantially cylindrical body. In particular, an axial length L24 of each blade is at least ninety percent (e.g., at least ninety-five percent) of an axial length L18 of the substantially cylindrical outer surface. In embodiments, and by way of example, the length L18 may typically be between twenty inches and fifty-four inches, and the body diameter may typically be between three inches and eight inches, depending upon the requirements of the cleaning machine.

In some embodiments, one or both of the axial end parts of the blade may be cut away externally of the substantially cylindrical surface, leaving only a portion within the channel, for the purpose of providing clearance for cleaning machine connections and/or axial blade retention structures as seen for example, in FIG. 7B. This configuration results in a lower portion 24k of the blade non-abrasive retaining part 24e extending to an axial position beyond the blade abrasive part 24a, where the lower portion 24k includes the head part 24g. Lower portion 24k can therefore be used for axial retention of the blade in the channel (e.g., by contact with and end cap or other retaining structure).

Per FIGS. 1-5, here, four blades 24 are provided, though fewer blades or more blades are possible, as per embodiments discussed below. Regardless of the number of blades, in embodiments, the blades are circumferentially spaced about the outer surface 18 of the substantially cylindrical body 12 to collectively substantially circumferentially span the substantially cylindrical outer surface 18 between the first end and the second end of the substantially cylindrical body. As seen in the axial end view FIG. 3, there is no circumferential location along the periphery of the substantially cylindrical surface 18 at which at least some part of the surface 18 is not axially aligned with part of the distal end of one of the blades 24. This feature is achieved by assuring that, in the case of four blades, each blade extends circumferentially through an angle α of at least ninety degrees (e.g., at least one-hundred degrees, such as at least one-hundred ten degrees or at least one-hundred twenty degrees), in axial end view per FIG. 4, between the first axial blade end and the second axial blade end. The embodiment of FIG. 4 shows an angle of approximately 110 degrees. Thus, the plurality of blades are positioned such that, for each blade of the plurality of blades, at least part of the blade axially overlaps with part of another blade, in axial end view. Incorporating this feature assures that part of the distal end of at least one of the blades 24 is in contact with the floor surface at all times, eliminating or at least reducing flutter and/or bounce.

Here, the blade abrasive part 24a of each blade comprises a thermoplastic (with or without fillers) and at least one abrasive grit material, such as one or more of silicon carbide, aluminum oxide, and diamond. In embodiments, the blade abrasive part 24a is joined to a blade non-abrasive retaining part 24 of the blade, wherein the blade abrasive part comprises a first thermoplastic and at least one abrasive grit material, the first thermoplastic having a first durometer, the blade non-abrasive retaining part comprising a second thermoplastic having a second durometer, wherein the first durometer is lower than the second durometer. In one implementation, the first durometer is no more than seventy-five percent (e.g., no more than sixty-five percent) of the second durometer. In one example, the first durometer may be a relatively low durometer, such as between 40 Shore D and 50 Shore D, such as between 43 Shore D and 47 Shore D (e.g., as per ASTM D2240 Peak Shore D hardness of 45 for Hytrel® 4556 material as the first thermoplastic), and the second durometer is harder, such as between sixty-seven Shore D and seventy-seven Shore D, such as between 70 Shore D and 74 Shore D (e.g., as per ASTM D2240 Peak Shore D hardness of 72 for Hytrel® 7256 material as the second thermoplastic), with the first thermoplastic being a thermoplastic polyester and the second thermoplastic being a thermoplastic polyester. Such a blade configuration and composition has been found to provide better performance, as compared to blade materials and compositions previously used in disc-style machines, in terms of achieving high polish without scratching the floor. The softer thermoplastic of the blade abrasive part facilitates exposure of the grit and lower applied force of the grit to the floor, while the harder thermoplastic of the non-abrasive blade retaining part facilitates retention of the blade to the substantially cylindrical body. In other embodiments, the plastics of the blade could be any of nylon, thermoplastic elastomers (TPE), thermoplastic polyurethane (TPU), or other elastomeric materials.

By way of example, in embodiments, the plastics material of the blade abrasive part, not inclusive of the abrasive grit material, has a first flexural modulus and the plastics material of the blade non-abrasive retaining part has a second flexural modulus, where the first flexural modulus is less than 40% of the second flexural modulus (e.g., the first flexural modulus less than 30% of the second flexural modulus, such as the first flexural modulus less than 25% of the second flexural modulus or the first flexural modulus less than 20% of the second flexural modulus), and where the flexural modulus is determined pursuant to ISO 178. In implementations, the first flexural modulus is between 60 MPa and 120 MPa (e.g., between 75 MPa and 100 MPa), and the second flexural modulus is between 440 MPa and 660 MPa (e.g., between 500 MPA and 600 MPa).

The material characteristics of the above two paragraphs may be implemented in the blades of any of the embodiments described herein (above or below). As used herein, “ASTM D2240” refers to the “ASTM D2240-15R21, Standard Test Method for Rubber Property—Durometer Hardness” test specification. As used herein, “ISO 178” refers to the “ISO 178: 2019, Plastics—Determination of flexural properties” test specification.

Variations of blades that utilize one or more thermoset materials and/or metal materials are also possible.

In embodiments, suitable abrasiveness of the blade abrasive part of the blades for the different concrete treatment processes are per Table 1 below. The grit ranges, and overlap, reflect the fact that a wide range of concrete characteristics exist in the field. Variations from the table are, however, possible.

TABLE 1

Abrasive Property

Concrete Treatment Process
Abrasiveness

Cleaning
up to 400 grit

Restoration/Honing
100 grit-2,000 grit

Polishing
1,000 grit or above

In one embodiment, the blade abrasive part 24a is joined to the blade non-abrasive retaining part 24e by a joining region 24f comprising a co-extrusion bond. That is, the two different compositions of the two parts, lower durometer with grit and higher durometer without grit, are co-extruded together such that the hot extruded materials bond to each other at the joining region 24f, such as by cross-linking of the materials, particularly at the central part or knit line of the joining region. In embodiments, per the example of FIG. 8A, the joining region 24f has a localized thickness T1 that is greater than both a thickness T2 of the distal end of the blade and a thickness T3 of a stem portion 24s of the non-abrasive blade retaining part, which stem portion 24s extends from the head end 24g and is thinner than the head end, for increasing a joint strength between the blade abrasive part and the non-abrasive blade retaining part. In some embodiments, the thickness of various portions of the blades could also be varied to achieve more beneficial bending stress distribution. By way of example, referring to FIGS. 47-49, the exemplary blade 24 has an overall height H24, the blade abrasive part 24a has a height H24a and the blade non-abrasive retaining part 24e has a height H24e. In exemplary implementations, the height H is between 1.5 and 2.0 inches (e.g., about 1.75 inches), the height H24a is between 1.0 and 1.5 inches (e.g., about 1.25 inches) and the height H24e is between 0.25 and 0.75 inches (e.g., about 0.5 inches). However, variations are possible. Generally, the height H24a will be greater than the height H24e (e.g., H24a at least 1.5 times H24e, such as H24a at least 2 times H24e). Again, however, other variations are possible. With respect to blade thickness, here, the joining region 24f has a localized increased thickness by way of a tapered thickness increase of both parts 24a and 24e. This not only provides more surface area for bonding between the two parts 24a and 24e, but also tends to shift the primary location of blade flexing upward, away from the joining region 24f, e.g., into location 24h, such that the joining region 24f region sees less bending stress and will, therefore, be less prone to failure.

In alternative embodiments, the blade abrasive part 24a is joined to the blade non-abrasive retaining part by one of adhesive bonding (e.g., using a cyanoacrylate adhesive or a two-part thermoset adhesive), welding (e.g., ultrasonic welding of the two plastics and/or plastic overwelding) or mechanical fastening. By way of example as to mechanical fastening, referring to the embodiment of FIGS. 44-46, the blade non-abrasive retaining part 24e is joined to the blade abrasive part 24a through use of plastic rivets 24i that pass through a bridging plate 24j (e.g., of suitable plastic or metal) and the respective parts 24a and 24g. Alternatively, the rivets 24i could pass through overlapping portions of parts 24a and 25b. In either case, the mechanical fastening could be the sole means of joinder, or could be in addition to other means, such as the co-extrusion bond, adhesive or welding.

In other embodiments, the blades could be formed by injection molding (e.g., injection molded plastic abrading elements impregnated with, or integrally molded with, abrasives such as diamond, silicon carbide, & aluminum oxide). In implementations, a two shot molding process could be used (e.g., one shot for the blade abrasive part and one shot for the blade non-abrasive retaining part).

With respect to retention of the blades 24 to the substantially cylindrical body 12, the non-abrasive blade retaining part 24e comprises a head end 24g opposite the distal end 24b of the blade. The substantially cylindrical body 12 includes a plurality of channels 30 opening to the substantially cylindrical outer surface 18. Each of the channels 30 extends substantially helically, and each of the channels 30 is at least partly undercut and sized to radially retain the head end 24b of a blade. Here, the channel 30 has a trapezoidal shape with a linear entry throat, and the head end 24g has an enlarged bead-shape. However, in other embodiments, each channel has a cross-sectional shape that substantially matches a cross-sectional shape of the head end (e.g., per FIG. 7A). In either case, in some embodiments, a slight friction fit between the head end and the channel may be provided.

In terms of manufacture and assembly, in one embodiment, the blades are extruded in a linear form. Each blade 24 slides into the open end of one of the channels, and the sliding operation along the helical channel, causes the blade to take on the desired helical shape, consistent with the helical shape of the channel. This configuration facilitates blade replacement, by sliding the blades back out of the channel ends. However, in some embodiments, in order to more rigidly secure the blades 24 into the channels, an adhesive may be applied within each channel for bonding the head end to the channel.

As mentioned above, the number of blades and the helical configuration of the blades, can be varied according to the desired performance of the abrasive device.

FIGS. 11-14 depict a four-blade embodiment in which each blade 24 extends circumferentially through an angle of ninety degrees, in axial end view per FIG. 14. This arrangement still provides a configuration in which the blades are circumferentially spaced about the outer surface 18 of the substantially cylindrical body 12 to collectively substantially circumferentially span the substantially cylindrical outer surface 18 between the first end and the second end of the substantially cylindrical body, where only small radial gaps 32 are seen in the axial end view of FIG. 13.

FIGS. 15-18 depict a four-blade embodiment in which each blade 24 extends circumferentially through an angle of approximately one-hundred thirty-five degrees, in axial end view per FIG. 14. This arrangement also provides a configuration in which the blades are circumferentially spaced about the outer surface 18 of the substantially cylindrical body 12 to collectively substantially circumferentially span the substantially cylindrical outer surface 18 between the first end and the second end of the substantially cylindrical body.

FIG. 19 depicts an eight-blade embodiment in which each blade 24 extends circumferentially through an angle of approximately one-hundred and ten degrees.

FIGS. 20-21 depict an embodiment with sixteen blades 24 extending along the substantially cylindrical body 12.

As mentioned above, the blade configuration is desirably such that at least part of the distal end of at least one blade is in contact with the floor surface at all times. In embodiments, at least part of the distal end of at least two blades is in contact with the floor surface at all times, per FIG. 22 showing a cross-section through a plane in which the body axis lies. In the embodiment of FIG. 21 at least part of the distal end of at least three blades would be contact with the floor surface at all times.

With respect to radial blade retention within the channels, in alternative embodiments a mechanical fastening system could be implemented. For example, in FIG. 23 a clamping plate 40 is located within the channel and secured in place with screws 42, with the clamping plate engaged onto the head part of the blade 24. In FIG. 24, the head of screw 42 itself engages with head part of the blade 24.

With respect to axial retention of the blades within the channels, end caps (e.g., per plate 44 in FIG. 25) may be provided at each end of the substantially cylindrical body 12 for such purpose. In one embodiment, the end caps 44 are secured by fasteners 46 extending through openings 48 into the end cap and engaging in holes in the end of the substantially cylindrical body 12, or threaded female inserts positioned within holes in the ends of the substantially cylindrical body.

Although two end caps may be used, embodiments utilizing only one end cap are also contemplated. In this regard, referring to FIGS. 26 and 27, a substantially cylindrical body 12 having helical channels 30 thereon is shown, where one channel axial end 30a is open to the first end 14 of the substantially cylindrical body, and the other channel axial end 30b is spaced apart from the second end 16 of the substantially cylindrical body 12. This configuration results in each channel having an end wall 30c that prevents blade movement axially toward the second end 16 of the substantially cylindrical body 12. Therefore, only the first end 14 of the substantially cylindrical body utilizes an end cap 50, which in FIG. 27 is sized to partially fit over an end part the substantially cylindrical surface 18 of the substantially cylindrical body 12. The end cap 50 include a series of slots 52 to receive axial end parts of the blades 24 as shown, which also provides increased support to the axial end part of each blade 24. The end cap 50 is removably secured to the substantially cylindrical body by mechanical fasteners (per above). In other embodiments, the end cap is removably secured to the substantially cylindrical body by an elastomeric band or the end cap is removably secured to the substantially cylindrical body by at least one spring member (e.g., a garter spring or a snap ring). For example, referring to FIGS. 50-51, an embodiment is shown in which the end of the substantially cylindrical body includes an annular channel 12e and associated lip 12f. An end cap in the form of a retaining ring 50a is positioned in the channel 12e, adjacent an outwardly facing edge 12g of the channel. The lip 12f include a set of cut-outs 12h, and the ring includes a set of correspondingly positioned radially inwardly extending tabs 50b such that the ring will slide axially into the channel 12e when the tabs are aligned with the cut-outs, and the tabs 50b will cooperate with the radially inward surface of the channel to center the ring. A retainer 50c is also positioned in the channel 12e to retain the ring 50a in place, and may take the form of any of an elastomeric band, a garter spring, a snap-ring, a zip tie, a wire tie or a hose clamp type structure. Alternatively, the retaining ring 50a could be eliminated and the retainer 50c or channel 12e resized for a snugger fit of the retainer 50c in the channel, such that the retainer 50c itself axially retains the blades without the need for the ring 50a, as shown in the partial cross-section of FIG. 52.

Axial retention of the blades in the channels can also be achieved using clamp configurations or a bayonet style cap.

In the above-illustrated embodiments, a radial height of each blade is substantially uniform along the full length of each blade. However, variations are possible. For example, referring to FIGS. 28 and 29, each blade has a radial height that is substantially uniform along an axial center region 60 of the blade and that tapers downwardly in both a first end region 62 at one end of the axial center region 60 and a second end region 64 at an opposite end of the axial center region. The taper may be a linear taper or a curved taper. This configuration achieves a more linear impact of the blade as it makes initial contact with the floor surface, rather than point impact, spreading the impact force over a lager zone in order to reduce noise, wear and vibration due to impact and to reduce failure rate due to fatigue. The relative size of the center region 60 and the end regions 62 and 64 could vary. In embodiments, each region 62, 64 might typically have a length that is no more than twenty percent of the overall blade length. However, other variations are possible. In terms of degree of taper, the taper could, for example, be anywhere between 5% and 75% of the total blade height. FIG. 29A shows, in solid line form, a taper 62a that runs 75% of the total blade height, and runs along both the blade abrasive part 24a and a portion of the blade non-abrasive retaining part 24e.

In other embodiments, the axial ends of the blade have one or more relief notches, such as lateral notch 25 shown in FIG. 29B, to increase flexing at the blade axial ends, again to reduce noise, wear and vibration due to impact and to reduce failure rate due to fatigue. The taper and the relief notches could also be combined, as suggested by exemplary dashed line tapers 62b and 62 in FIG. 29B.

In the above embodiments, the channels may be formed in the substantially cylindrical body via a machining operation. In one implementation, the substantially cylindrical body is a tubular polyethylene (e.g., HDPE) extrusion into which the channels are machined, but other body materials are possible (e.g., other rigid plastics or a tubular aluminum extrusion). In addition, the substantially cylindrical body may be formed of multiple pieces.

FIGS. 30-31 depict an embodiment in which the substantially cylindrical body 12 is formed of a set of four helical body parts 12a, 12b, 12c and 12d that are connected together (e.g., by welding, adhesive or mechanical fastening). The helically running edges of the helical body parts 12a-12d are cooperatively configured such that when adjacent edges abut, a channel is formed with the desired undercut channel profile to retain the blades 24.

FIGS. 32-33 depict an embodiment in which a series of helically running clamp plates 70 are attached (e.g., by adhesive or fasteners) to the substantially cylindrical outer surface 18 of the substantially cylindrical body to retain the blades 24. The helically running edges of the helical clamp plates 70 are cooperatively configured such that when adjacent edges abut, a channel is formed with the desired undercut channel profile to retain the blades 24. Other clamp configurations are possible.

Embodiments in which channels are not utilized for blade retention are also possible.

FIG. 34 depicts an embodiment in which the blade includes a T-shaped head and a set of wire form retainers 74, running along each side of the blade head, are secured (e.g., by fasteners 76) to the substantially cylindrical body 12 to retain the head part against the substantially cylindrical outer surface 18.

FIG. 35 depicts an embodiment in which each blade is substantially L-shaped in axial end profile such that fasteners 78 are easily engaged with the leg of the L-shape to retain the blades on the substantially cylindrical body 12. As an alternative to the fasteners 78, the leg of the L-shaped could be secured to the substantially cylindrical body using an adhesives (e.g., substantially cyanoacrylate or a two-part thermoset).

The substantially cylindrical bodies, regardless of which of the above configurations are utilized, can be sized to mount within existing cylinder style cleaning machines. Accordingly, different sizes etc. for different machines may be employed. However, in order to reduce the number of variations, end caps may be utilized that enable a common substantially cylindrical body configuration 112 to be mounted on multiple different machines, per the end cap 80 shown in FIG. 36. Multiple different end cap configurations would be provided as needed to mount to the multiple different machines. Each end cap would convert the drive rib configuration of the standard body configuration 112 to the necessary drive rib (or other drive structure) configuration required for a given machine. Thus, a method of using a standard body configuration to produce and use abrasive devices would involve (i) producing a standard body with a set configuration, (ii) mounting a first end cap to a first instance of the standard body, the first end cap configured to enable the standard body to mount in a first machine, (iii) mounting a second end cap to a second instance of the standard body, the second end cap configured to enable the standard body to mount to a second machine, etc.

FIGS. 37-39 depict an embodiment in which each blade 100 is encapsulated in a retention device 102 that is secured to the substantially cylindrical body by a T-slot connection 104. The blade 100 could be rigid, such as comprised of metal, such that the device could be used for deep cleaning or restoration of the concrete floor by flattening it, and the retention device 102 could be a softer material that flexes to help the blade to stay in contact with uneven floor surfaces for the purpose of flattening & could also provide some sound dampening.

FIGS. 40-42 depict an embodiment in which a blade 110 is integrally extruded with an enlarged tubular base area 112, with the blade secured by a T-slot connection 114. The blade 110 can be used for restoration of the concrete floor by flattening it and the base area 112 can also flex to help the blade to stay in contact with uneven floor surfaces for the purpose of flattening the floor surface. The flexing base area 112 can also provide some sound dampening.

In any of the above embodiments, support structure may also be provided for the blades. For example, referring to FIG. 43, an abrasive device include L-shaped blades 24, mounted by fasteners 78, wherein the rotationally trailing side of each blade is supported by an adjacent set of brush elements or tufts 90. Each brush tuft 90 may be formed by a collection of bristles, and each brush tuft may be mounted in a respective opening on the substantially cylindrical surface of the substantially cylindrical body 12.

Referring to FIGS. 53-60, another embodiment of an abrasive device 210 includes a substantially cylindrical body 212 with a substantially cylindrical outer surface 214 facing radially away from a body axis 216. The body 212 is hollow, with an inner surface 217 oriented radially toward the axis 216. The body 212 has a radial thickness T2 and a length L2 along the axis 216 between first and second ends 218, 220 of the body 212. The body 212 has an inner diameter ID and an outer diameter OD measured perpendicularly through the axis 216. In some embodiments, as illustrated in the example of FIGS. 53-55, the body 212 has a substantially uniform size with respect to the length L2 from the first end 218 to the second end 220.

With further reference to FIGS. 54 and 55, the body 212 of the device 210 includes one or more blade slots 222 extending into and along the outer surface 214 of the body 212. In some embodiments, the body 212 includes four blade slots 222. In some embodiments, one or more blade slots 222 axially extend along all or substantially all of length L2. In some embodiments, as illustrated in the example of FIGS. 59A and 59B, the blade slots 222 have varying cross-section profile, with a radially inward, relatively wider base aperture segment 223 defined at least partially within the body 212 and a narrower stem or throat aperture segment 224 extending, at least in part, radially outwardly from the base aperture to the outer surface 214.

With continuing reference to the example illustrated in FIGS. 53-58, each of the four blade slots 222 vary radially along the length L2 of the body 212. For example, exemplary blade slots 222 each have a quarter-helical shape. Moreover, adjacent ones of the blade slots 222 axially overlap with each other, at least at the opposing first and second ends thereof. For example, first end 225a of blade slot 222a axially overlaps with second end 226b of the blade slot 222b. With such a configuration and shape of the blade slots 222, the blade slots 222 collectively overlap, in at least one place along length L2, the entire circumference of the outer surface 214. It should be understood that the number, configuration, and shape of blade slots 222 can vary according to the principles of the present disclosure.

The body 212 of the device 210 includes apertures or holes 230 in the outer surface 214 adjacent blade slots 222. In some embodiments, a plurality of holes 230 in outer surface 214 of the body 212 are provided in series on each side of each blade slot 222. On each side of one of the blade slots 222, the holes 230 are substantially equally spaced in the axial direction from each other. Relative to each of the blade slot 222, the adjacent holes 230 have opposing radial positions substantially equally spaced from the blade slot 222.

The body 212 is, in some embodiments, HDPE material. It should be understood that the body 212 may be manufactured out of a variety of thermoplastic materials that can be extrusion molded and provide properties consistent with the ability to retain blades and bristles.

According to the principles of the present disclosure, the holes 230 are configured to receive and secure, respectively, one of brush elements or tufts 232. The tufted material of the tufts 322 is, in some embodiments, made of nylon or polypropylene. It should be understood that additional materials may be used for the bristles, including, for example, steel wire. In some embodiments, tufts 232 contain abrasive regions independent of the abrasive regions of the blades 250.

The device 210 further includes a plurality of abrading elements, such as exemplary blades 250. The blades 250 extend radially outwardly of the outer surface 214 from the blade slots 222, respectively, and the blades 50 extend over substantially all of the length of the blade slots 222, respectively.

With further reference to FIG. 60, an individual one of the blades 250, in some embodiments, has a base or head portion 253 and a stem portion 254. The stem portion 254 extends from a first surface 256 of the base portion 253, and the main and base portions combine to have a T-shaped cross-sectional shape. The base portion 253 of the blades 250 is configured and sized to be received and secured within the base aperture 223 of the blade slots 222. In some embodiments, the base portion 253 is greater in one or more dimensions, and the blades 250 engage the body 212 in an interference fit, with the blades 250 deforming at the base portion 253. The stem portion 254 of the blades 250 is configured and sized to be complementary to the stem aperture 224 of the blade slots 222, such that the stem portion 254 of the blades 250 extends through and is supported by the stem aperture of the blade slots 222.

The blades 250 further include an abrasive region 260 at the distal end of the stem portion 254, opposite the base portion 253, at which abrasive material A is secured to the blades 250. In some embodiments, blades 250 are made of a thermoplastic material that will be extrusion molded. Exemplary materials include nylon, TPE, TPU or other elastomeric materials. In some embodiments, the abrasive material A includes diamond particulates sintered to the blades 250 ranging in grits from 25 to 5000. In some embodiments, abrasive material A may include silicon carbide, aluminum oxide and/or a combination of silicon carbide, aluminum oxide, and/or diamond. According to the principles of the present disclosure, the blades 250 may include segments varying abrasive grit.

In some embodiments, blades 250 are attached to the body by sliding the blade into a channel or slot that has been manufactured in the body, such as exemplary blade slots 222. Blades 250 may also be attached in some embodiments by mechanically fastening to the body 212 using staples, an adhesive, or a secondary retainer that will be attached to the body. In some embodiments, blades 250 are continuous in an axial direction along the body. In other embodiments, blades 250 are segmented along the axial direction. The device according to the principles of the present disclosure may have blades configured in one or more patterns, including helical and chevron patterns.

The dimensions of the body 212 are, in some embodiments, set to conform to existing floor cleaning machines. For example, in some embodiments of the device 210, the length L is approximately 236 inches, the thickness T is approximately ½ inch, the outer diameter OD is approximately 3⅙ inches, and the inner diameter ID is approximately 2⅙ inches. In such an exemplary embodiment, holes 30 have a diameter of approximately 9/32 inch, and fifty-three of holes 230 are placed in series adjacent each side of each of blade slots 222. Further, in such an exemplary embodiment, the blades 250 have base portions 253 approximately ⅜ inch wide and 1/10 inch thick and have stem portions approximately 1 25/32 inches long and approximately ⅛ inch wide. The base aperture 223 of the blade slots 222 has a width of ¼ inch and a thickness of approximately 9/64 inch, such that the base portions 253 of the blades 250 compress across the width thereof, and the base aperture 223 accommodates the deformation with increased thickness. The stem aperture 224 of the blade slots 222 is sized to support the stem portion 254 of the blades 250 without deformation, e.g. the stem aperture 224 has a width within 1/100 inch of the stem portion 254.

In such an exemplary embodiment, and in other embodiments, the device 210 is operable to receive the drive shaft of a rotary machine, including an automatic floor cleaning machine (not shown). The floor cleaning machine can be of a type that traditionally cleans concrete floors in which the axis of rotation of a cylindrical cleaning or abrasive element is positioned substantially parallel to the floor. The drive shaft may impart motion to the device 210 at approximately 300-2400 rpms while applying approximately 30-550 lbs. of total pad pressure. There are several known types of automatic floor cleaning machines, including cylindrical floor scrubbers and floor sweeper scrubbers. Such devices may include walk behind, ride-on, and autonomous units. These units are in operation in a wide variety of environments to clean and polish any hard flooring surface in commercial and industrial settings.

The following paragraphs describe potential aspects of the above-described embodiment with brush tufts.

A1. An abrasive device for use on concrete floors comprising: a substantially cylindrical body having a substantially cylindrical outer surface extending about a body axis and between first and second ends, the body configured to engage a rotary cleaning machine and be driven about the body axis; one or more blades extending radially outwardly from the cylindrical outer surface of the body, the one or more blades including a blade abrasive region extending from a distal end thereof; and first and second brushing members adjacent the one or more blades, respectively, the first and second brushing members secured to the body and extending radially outwardly from the cylindrical outer surface of the body, the distal end of the one or more blades radially extending at least partially beyond the first and second brushing members.

A2. The abrasive device of aspect A1, wherein the one or more blades substantially axially span the cylindrical outer surface between the first and second ends of the body.

A3. The abrasive device of aspect A1, wherein one of the one or more blades substantially axially spans the cylindrical outer surface between the first and second ends of the body.

A4. The abrasive device of aspect A3, wherein the device includes four of the one or more blades, each of the four blades substantially axially spanning the cylindrical outer surface between the first and second ends of the body.

A5. The abrasive device of aspect A4 wherein the four blades are circumferentially spaced about the outer surface of the body to collectively substantially radially span the cylindrical outer surface between the first and second ends of the body.

A6. The abrasive device of aspect A5, wherein the four blades each have a quarter helical shape.

A7. The abrasive device of aspect A1, wherein the one or more blades substantially radially span the cylindrical outer surface between the first and second ends of the body.

A8. The abrasive device of aspect A1, wherein the first and second brushing members are disposed on opposing sides of the one or more blades, respectively.

A9. The abrasive device of aspect A1, wherein the first and second brushing members are disposed on opposing sides of each one of the one or more blades, respectively.

A10. The abrasive device of aspect A1, wherein the first and second brushing members have first and second brush heights relative to the body, respectively.

A11. The abrasive device of aspect A10, wherein the first and second brushing members are spaced apart from one of the one or more blades along the body at first and second gap distances, respectively, the first and second gap distances being less than the first and second brush heights, respectively.

A12. The abrasive device of aspect A1, wherein the first and second brushing members partially radially overlap the blade abrasive region of the one or more blades.

A13. The abrasive device of aspect A1, wherein the blade abrasive region extends over the distal end of the one or more blades onto opposing faces of the one or more blades, respectively.

A14. The abrasive device of aspect A1, wherein the blade abrasive regions radially extend over half of the respective radial heights of the one or more blades from the outer surface of the body.

A15. The abrasive device of aspect A1, wherein the blade abrasive regions of the one or more blades include one or more of silicon carbide, aluminum oxide, and diamond abrasive materials.

A16. The abrasive device of aspect A1, wherein each of the one or more blades have a flange end opposite the distal end, the body includes one or more channels opening to the outer surface, the channels having complementary cross-sectional shapes to the flange ends of the one or more blades, the channels receiving the flange ends of the one or more blades to couple the one or more blades to the body.

A17. The abrasive device of aspect A16, wherein the one or more blades are secured to the body by a friction fit between the flange ends and the channels, respectively.

A18. The abrasive device of aspect A1, wherein the blades are mechanically secured on the outer surface of the body.

A19. The abrasive device of aspect A1, wherein the first and second brushing members each include abrasive regions on tuft elements thereof.

The abrasive device of claim 19, wherein the abrasive regions of the first and second brushing members have a grit size different from a grit size of the blade abrasive regions.

“Substantially” as used herein means that a dimension, time duration, shape, or other adjective may vary slightly from what is described due to physical imperfections, power interruptions, variations in machining or other manufacturing, etc.

It is to be clearly understood that the above description is intended by way of illustration and example only, is not intended to be taken by way of limitation, and that other changes and modifications are possible. Many modifications and variations of the present disclosure are possible in light of the above teachings, and the disclosure may be practiced otherwise than as specifically described.

Although the above embodiments disclose body structures that are substantially cylindrical in shape, with a substantially cylindrical outer surface, which is shown in particular as a right circular cylinder, other cylinder shapes are possible. For example, abrasive device embodiments in which the body has an oval (in axial end view) substantially cylindrical outer surface or a multi-sided (e.g., 4-20 sides in axial end view) substantially cylindrical outer surface could be implemented. Still further, abrasive device embodiments in which the body does not have a substantially cylindrical outer surface are also possible. For example, an embodiment in which the body has barrel-shaped curve (larger diameter in the middle and shorter diameter on the axial ends) in side elevation view (e.g., per the shape of body 312 in FIG. 61) or in which the body is tapered at the axial ends in side elevation view (e.g., per the shape of body 314 in FIG. 62) are possible. All such body forms, cylindrical (right circular or other) and non-cylindrical, are consistent in being elongated bodies in which an axial length of the body is substantially larger than a largest dimension of the body in a cross-section taken along a plane perpendicular to the body axis (e.g., the axial length of the body is typically at least three times the largest cross-sectional dimension, such as at least four times the largest cross-sectional dimension or at least five times the largest cross-sectional dimension). In addition, all such body forms have an outwardly facing body surface that extends substantially the axial length of the body, between the two axial ends of the body, and that surrounds the body axis (i.e., a substantially cylindrical outer surface is just one form of such an outwardly facing body surface). In many cases such bodies will be of tubular form, as per the above-illustrated embodiments, but variations in which the body is solid are also possible.

Moreover, the helical orientation of the blades described above in the case of the right circular cylinder embodiments is just one example of a blade orientation that is angularly offset from the body axis. Other angularly offset blade orientations could include, for example, linearly running blades on the sides of a multi-sided substantially cylindrical body, such the exemplary body 316 shown in FIG. 63, where the blade channels 318 run linearly at a constant non-zero angle relative a direction parallel to the body axis 320.

Any of the above-described abrasive devices can be incorporated into a cylindrical style cleaning machine, such as the machine 350 depicted in FIG. 64, which includes two abrasive devices 352 (e.g., elongated bodies with blades and body axes oriented substantially horizontal), a motor 354 and drive system 356 through which the motor 354 effects rotation of the abrasive devices. Such cleaning machines can be push-type machines, drivable machines or even autonomous self-driving machines.

Still, other embodiments of abrasive cleaning devices are possible. Referring to FIGS. 65-69, an abrasive device 410 is shown in which the elongated body 412, here substantially cylindrical (but alternatively other configurations as noted above), has an outwardly facing surface, here substantially cylindrical (but alternatively other configurations as noted above), is wrapped with an abrasive structure 414. The abrasive structure 414 takes the form of a molded unit comprising a base 414a, in the form of an initially flat or planar sheet, and multiple sets of projecting blades or fingers 414b. The abrasive structure may, for example, be molded of suitable materials, such as TPE, TPO (thermoplastic polyolefins) or TPU, and the incorporated abrasive grit material may be any of silicon carbide, aluminum oxide, and diamond. In some embodiments, the abrasive grit material may be incorporated into both the base 414a and the blades or fingers 414b, and in other embodiments the abrasive grit material may be incorporated into only the blades or fingers 414b. The abrasive structure 414, when wrapped, takes on the form of the body 412, with the base 414a lying adjacent the outwardly facing surface of the body 412. The abrasive structure 414 is secured to the body 412 by, for example, adhesive or fasteners (e.g., screws passing through the base 414a and into the body 412) or clamping structure (e.g., wire forms or end caps that engage end sections of the abrasive structure 414 and the body 412) or other mechanical retainers. The abrasive structure 414 can be configured and wrapped such that the sets of blades or fingers 414b are offset from the axis 420 of the body, such as the helical orientation shown. Here, each set of the blades or fingers is comprised of three aligned rows of blades or fingers 414b the blades or fingers 414b are shown with a generally rectangular form, but other variations are possible, such as fewer rows or more rows, or round, oval or other shape projections. Here, the set of abrasive projections are collectively positioned such that, for each rotational position of the elongated body about the body axis when the abrasive device is adjacent a floor surface with the body axis substantially parallel to the floor surface, at least part of one of the abrasive projections will be in contact with the floor surface.

FIGS. 70-73 show another embodiment of an abrasive device 450 in which the elongated body 452 is wrapped with a set of abrasive structures, here a series of abrasive strips 454. The abrasive strips 454 are similar to the above abrasive structure 414, except that each strip 454 includes a base 454a that carries only a single set of blades or fingers 454b. Again, the wrapped strips 454 may be secured to the body 452 by any of adhesive or fasteners (e.g., screws passing through the base 454a and into the body 452) or clamping structure (e.g., wire forms or end caps that engage end sections of the abrasive structure 454 and the body 452) or other mechanical retainers. The strips can be wrapped in a pattern that is angularly offset from the body axis 460, such as the exemplary helical orientation shown. Here, the set of abrasive structures are collectively positioned such that, for each rotational position of the elongated body about the body axis when the abrasive device is adjacent a floor surface with the body axis substantially parallel to the floor surface, at least part of one of the abrasive projections will be in contact with the floor surface.

In still other embodiments, the abrasive structure could be formed in smaller strips or sheets could be placed in various non-contiguous locations on the outwardly facing surface of the tube. By way of example, FIGS. 74-77 show such an exemplary abrasive device 470 in which the elongated body 472 has a plurality (e.g., 15 or more, such as 20 or more or 25 or more) of discrete abrasive structures 474 positioned on the outwardly facing body surface. Each abrasive structure 474 is, here, a smaller version of the above abrasive structure 454. Each abrasive structure 474 has a plurality of abrasive projections 474b extending, at least in part, radially outwardly from the outwardly facing body surface. Each abrasive structure comprises a molded unit including a base 474a that abuts the outwardly facing body surface and the plurality of abrasive projections 474b extend from the base. Again, the structures 474 may be secured to the body 472 by any of adhesive or fasteners (e.g., screws passing through the base 474a and into the body 472) or clamping structure (e.g., wire forms or the like) or other mechanical retainers. Here, the plurality of abrasive structures 474 are collectively positioned on the outwardly facing body surface such that, for each rotational position of the elongated body about the body axis 480 when the abrasive device is adjacent a floor surface with the body axis 480 substantially parallel to the floor surface, at least part of one of the abrasive projections 474b will be in contact with the floor surface.

In embodiments, the plurality of abrasive structures 474 are collectively positioned on the outwardly facing body surface such that, in axial end view, each abrasive projection 474b axially aligns with at least part of one other abrasive projection.

ABRASIVE DEVICE FOR FLOOR SCRUBBING, CLEANING AND/OR POLISHING

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