FLOOR MAINTENANCE MACHINE USING A SPIRAL, TUFTED, CYLINDRICAL

BRUSH

BACKGROUND

The present invention generally relates to floor maintenance, particularly to both sweeping and wet scrubbing floors while removing only a negligible amount of floor finish, and specifically to novel cylindrical brushes which sweep and wet scrub without noticeably scratching or dulling the floor and to floor maintenance machines utilizing such novel brushes.

Floor maintenance on finished floors typically involves several separate operations. On floors such as resilient tile, polished concrete or colored epoxy, a floor finish is applied to the floor. The floor finish protects the floor surface and provides a glossy, clean appearance. Often, several coats of finish are applied to provide additional protection and longer wear.

Daily maintenance is performed by first pre-cleaning such as pre-sweeping or dust-mopping to remove debris from the floor. This is followed by scrubbing with an automatic scrubber. Automatic scrubbers dispense cleaning solution onto rotating agitator disc pads or brushes. The spent cleaning solution is then recovered with a vacuumized squeegee. Operation of automatic scrubbers is well known.

The scrubbing operations also remove a small amount of floor finish. This is due to the abrasive composition of the scrub pads/brushes. The rotation of the pads/brushes creates very small scratches in the finish which dull the appearance of the floor. In order to restore the floor finish back to a glossy appearance, the scrubbing operation is followed by high speed burnishing. Burnishing also removes a small amount of finish from the floor. Burnishing is a dry polishing process, and some of the dry, powdered floor finish

becomes airborne and settles back onto the floor and surrounding surfaces. This often necessitates yet another operation to dust-mop the floor.

Restoration of finish requires periodic stripping and recoating of finish. The majority of the cost of floor maintenance is not the equipment or the cleaning chemicals, but the labor to perform the above steps. If one or more steps in the process can be completely eliminated, the overall cleaning cost can be reduced significantly.

One conventional solution was to combine the pre-cleaning and scrubbing operations into one machine such as by using cylindrical scrub brushes instead of the more common disc style pads/brushes. The cylinder brushes sweep debris into a hopper while simultaneously performing the task of scrubbing. These cylinder brushes typically rotate at around 900 RPMs or less. The bristles on these cylinder brushes tend to be relatively stiff so that they can both sweep and scrub. Like disc brushes, the cylindrical scrubbers currently on the market remove a small amount of finish and create small scratches in the floor finish. As a result, they dull the appearance of the floor. So while cylindrical brush scrubbers currently available eliminate the need to pre-clean, they do not reduce or eliminate the need to burnish the floor to restore an acceptable level of gloss.

Attempts have been made to combine the scrubbing and burnishing operations into one machine so that they can be performed simultaneously such as disclosed in U.S. Patent No. 6,023,813. Such machines still require pre-cleaning, do not address the removal of finish by the abrasive scrub pads, and may still require post-mopping to remove powdered floor finish residue. Further, such dual function machines are expensive and cumbersome to operate.

Thus, the present invention addresses a need in floor maintenance to reduce or eliminate steps in the daily cleaning of finished floors.

SUMMARY

The present invention solves several of the problems involved in daily floor maintenance by providing a machine that sweeps and wet scrubs while removing only a negligible amount of floor finish, and which does not noticeably scratch or dull the floor. This invention thus eliminates the need for pre-sweeping, frequent burnishing, and post- mopping. Additionally, because far less finish is removed, the frequency of stripping and recoating the floor is greatly reduced.

In a first aspect, the present invention relates to a brush and a floor maintenance machine utilizing such a brush. A multiplicity of rows of a multiplicity of tufts of bristles are equally circumferentially spaced on the cylindrical outer surface of a cylindrical core, are arranged at an acute angle to the rotational axis to create a spiral, and repeat in at least one identical row pattern upon the cylindrical outer surface. Tufts of an adjacent trailing row are indexed laterally from a leading row by an index distance less than one half of the equal spacing of the tufts in each of the multiplicity of rows. In a further aspect of the present invention, counter rotating leading and trailing cylindrical brushes move in an operation direction with their rotational axes being spaced and parallel to each other and to the floor. The rotational speed of the trailing cylindrical brush is greater than that of the leading brush to enhance sweeping performance. In most preferred forms, the leading and trailing cylindrical brushes are of identical construction and include tufts of bristles arranged in a multiplicity of rows arranged at an acute angle to the rotational axis of the brush.

In still a further aspect of the present invention, a cylindrical brush moving in an operation direction parallel to the floor is rotated about a rotational axis at a rotational speed in the order of 1200 to 1800 RPMs to enhance polishing benefit. In most preferred

forms, the brush includes tufts of bristles arranged in a multiplicity of rows arranged at an acute angle to the rotational axis of the brush.

The present invention will become clearer in light of the following detailed description of an illustrative embodiment of this invention described in connection with the drawings.

DESCRIPTION OF THE DRAWINGS

The illustrative embodiment may best be described by reference to the accompanying drawings where:

Figure 1 shows a perspective view of a floor maintenance machine according to the preferred teachings of the present invention.

Figure 2 shows an exploded perspective view of portions of a floor maintenance machine of Figure 1.

Figure 3 shows a perspective view of a cylindrical brush utilized in the floor maintenance machine of Figure 1. Figure 4 shows a front elevation view of the cylindrical brush of Figure 3.

Figure 5 shows an end elevation view of the cylindrical brush of Figure 3. Figure 6 shows a diagrammatic view of the outer surface of the cylindrical brush core of Figure 3 with the tufts of bristles removed and with the outer surface unwrapped. All figures are drawn for ease of explanation of the basic teachings of the present invention only; the extensions of the figures with respect to number, position, relationship, and dimensions of the parts to form the preferred embodiment will be explained or will be within the skill of the art after the following description has been read and understood. Further, the exact dimensions and dimensional proportions to conform to specific force, weight, strength, and similar requirements will likewise be within the skill of the art after the following description has been read and understood.

Where used in the various figures of the drawings, the same numerals designate the same or similar parts. Furthermore, when the terms "top", "bottom", "first", "second", "front", "back", "height", "width", "length", "end", "side", "trailing", . "leading", "horizontal", "vertical", "axial", "radial", "longitudinal", "lateral", and similar terms are used herein, it should be understood that these terms have reference only to the structure shown in the drawings as it would appear to a person viewing the drawings and are utilized only to facilitate describing the illustrative embodiment. DESCRIPTION

A floor surface maintenance machine such as a floor surface sweeping and wet scrubbing machine according to the preferred teachings of the present invention is diagrammatically shown in Figure 1 and generally designated 10. In the preferred form shown, machine 10 is movably supported by three or more wheels, casters or the like 12 upon the surface to be cleaned, with one or more of the wheels, casters or the like 12 being driven if desired. The operator can either walk behind or ride upon machine 10 as desired. Machine 10 includes suitable elements for maintaining the floor surface such as first and second rotatable cylindrical brushes 14 mounted to machine 10 for rotation about spaced parallel rotational axes 42 parallel to the floor as diagrammatically shown. In the most preferred form shown, brushes 14 are of identical construction. A cleaning solution such as but not limited to water and water-based solutions (which can be premixed or which could be separately provided and mixed within the machine 10 where desired) is delivered via line 15 from a source of cleaning solution in the form of a solution tank 16 adjacent to brushes 14 such as by a solution pump 18 in fluid communication with tank 16. Jn the preferred form, machine 10 includes a recovery tank 26 and a suitable vacuum system including a solution pickup element 28 such as squeegee as diagrammatically

■ shown for collecting solution from the surface to be cleaned and delivering such collected solution to recovery tank 26.

In a most preferred form where machine 10 sweeps as well as wet scrubs the floor surface, a hopper 33 is positioned above and intermediate the first and second brushes 14 for receiving debris swept from the floor as brushes 14 are simultaneously moved in an operation direction parallel to the floor. It should be appreciated that hopper 33 allows solution and small particles to flow therethrough to the floor but retains debris and large particles which can be manually removed such as by sliding hopper 33 from machine 10 and emptying. However, hopper 33 can take other forms and/or could be eliminated in certain embodiments according to the preferred teachings of the present invention.

Machine 10 as previously described can be of a variety of types and forms, and the present invention is not intended to be limited to any particular type or form including but not limited to the type or form shown and/or described.

According to the teachings of the present invention, each brush 14 generally includes a cylindrical core 40 mounted for rotation about rotational axis 42. In the most preferred form shown, cylindrical core 40 is in the form of a tube which is slideably received on spindles 44. At least one of such spindles 44 of each brush 14 is rotated by a motor 46 through a suitable drive such as sheaves and a V-belt 48. It should be appreciated that core 40 can have other forms as is known in the art. Similarly, core 40 can be driven by different manners as is known in the art according to the teachings of the present invention such as, but not limited to, by a single motor 46 while having drives resulting in the desired speed relationship, or the like. In any case, each cylindrical core 40 includes a cylindrical outer surface 50 having a core diameter D3 and concentric to rotational axis 42 at a radial spacing equal to one half of core diameter D3.

In the most preferred form, core 40 includes a multiplicty of drilled tuft holes 52 extending radially into cylindrical outer surface 50. Each of the tuft holes 52 has a diameter 52a. Each of tuft holes 52 receives a multiplicity of individual bristles B to define an individual tuft 54 extending radially from rotation axis 42. According to the teachings of the present invention, tuft holes 52 and thus tufts 54 are arranged as a multiplicity of rows R. Specifically, in the form shown, rows R are spaced by a row spacing S circumferentially around cylindrical outer surface 50, and in the most preferred form, row spacing S is equally spaced between each of rows R around the entire cylindrical outer surface 50. Likewise, each of the rows R includes a multiplicity of tuft holes 52 and tufts 54 which are spaced by a tuft spacing I. In the most preferred form, tuft spacing I is equally spaced in each and every row R, and row spacing S is generally equal to tuft spacing I.

According to the teachings of the present invention, cylindrical brush 14 includes several features which cooperate together to produce synergistic results. One such feature is that rows R of spaced tufts 54 of bristles B are arranged in a spiral at an acute angle Al to the rotational axis of between 15 and 25° and preferably in the order of 20° when measured at surface 50 unrolled and lain flat. Spiraling tufts 54 minimize imprints of tufts 54 on the floor finish as occurs when tufts are arranged in straight rows across the brush. Further, in the preferred form where each tuft 54 in brush 14 is formed by a multiplicity of individual bristles B received in drilled tuft hole 52 in core 40, the diameter D3 of core 40 of brush 14 is in the range of 2 to 5 inches and in the most preferred form in the order of 2.9 inches. The diameter 52a of drilled tuft hole 52 in core 40 is in the range of 0.25 to 0.375 inches and in the most preferred form in the order of 0.31 inches. The length of bristles B extending from tuft hole 52 is in the range of 1.25 to

1.75 inches and in the most preferred form in the order of 1.5 inches. The ratio of length of bristles B to the diameter of tuft drill hole 52 is in the range of 4.5:1 to 5:1 and in the preferred form in the order of 4.8: 1. Each bristle B in the preferred form is formed from 0.008 inch crimped type 6.12 nylon in the preferred form. The crimp amplitude is around 0.025 inch and the pitch is around 0.11 inch. Bristles B could also be formed by polypropylene having a similar flex modulus or other water resistant bristle material according to the teachings of the present invention. Likewise, although crimping adds fullness to tufts 54, bristles B could be flagged to add fullness according to the teachings of the present invention. In addition to diameter, material and type, performance of tuft 54 is affected by length of bristles B and the number of tufts 54 per area. Specifically, the distance I between adjacent tufts 54 within the same row R is in the range of 0.50 inch to 0.75 inch and in the most preferred form is in the order of 0.59 inch. The exact distance I between tufts 54 is determined by the length of rows R along the working length Dl of brush 14. The length of rows R is divided by the preferred distance and rounded to the nearest whole number.

Ih the preferred form, the spacing S between rows R of spaced tufts 54 of bristles B is generally the same as the distance I between adjacent tufts 54 in rows R in the preferred form. The number of rows R should result in row patterns repeating itself at least once for each full rotation of brush 14. In the preferred form, the number of rows R of tufts 54 is in the range of 14 to 18 rows R and in the most preferred form in the order of 16 rows R. As an example, a 16-row brush 14 could have either two or four identical groups of eight rows or four rows R, respectively. A 15-row brush 14 could have three identical pattern groups of five rows R each. An 18-row brush 14 could have either two or three identical groups of nine rows R or six rows R, respectively.

Additionally, tufts 54 are indexed such that tufts 54 in trailing rows R are indexed laterally by a distance T from tufts 54 in the preceding or leading row R. Distance T depends upon the number of rows R and the number of repeat patterns formed by the rows R. Particularly, distance T is equal to the distance I between tufts 54 in the same row R divided by the product of the number of rows R in turn divided by the number of repeat patterns. In the preferred form, distance T is of an amount no greater than in the order of one half of diameter 52a of tuft holes 52 in cylindrical outer surface 50 of brush 14 for receiving tufts 54 and not less than one ninth of diameter 52a of tuft holes 52 in cylindrical surface 50 of brush 14 for receiving the tufts 54. m the most preferred form, distance T is in the order of one quarter of diameter 52a of tuft holes 52 in cylindrical outer surface 50 of brush 14 for receiving tufts 54.

Furthermore in the most preferred form, at least one of brushes 14 is rotated by floor maintenance machine 10 faster than cylindrical brushes of conventional automatic scrubbers such that the tip speed of bristles B is faster in the present invention than in conventional automatic scrubbers. Specifically, cylindrical brushes of convention automatic scrubbers were typically rotated at 900 RPMs and resulted in individual tuft imprints on the floor finish. In the preferred form for brush 14 having a diameter D2 in the order of 5.9 inches, the trailing brush 14 in the direction of travel is counter rotated at a speed in the range of 1200 to 1800 RPMs and preferably in the order of 1500 RPMs, and with the preferred bristle length resulting in a tip speed in the range of 1850 to 2750 feet per minute and preferably in the order of 2300 feet per minute. Such speeds according to the preferred form of the present invention synergistically resulted in polishing benefits which were not obtained at conventional speeds. However, it should be appreciated that in the preferred form, the angle Al and speed are related. For any

given RPM, if angle Al is too shallow or too great, row effect or tuft imprints as experienced with conventional automatic scrubbers may result.

Further in the preferred form, the rotational speed of leading and trailing brushes 14 are different, with trailing brush 14 in the direction of travel rotating faster than the leading brush 14. In the most preferred form, where trailing brush 14 rotates in the order of 1500 RPMs, the leading brush 14 is rotated in the order of 900 RPMs. It was surprisingly discovered that sweeping performance of machine 10 was better when brushes 14 were rotated at differing speeds, and the polishing benefit was still obtained if trailing brush 14 was rotated faster than conventional speeds. Thus since the invention disclosed herein may be embodied in other specific forms without departing from the spirit or general characteristics thereof, some of which forms have been indicated, the embodiments described herein are to be considered in all respects illustrative and not restrictive.