Patent Publication Number: US-2007099549-A1

Title: Abrasive cleaning and honing device and method of honing concrete surfaces

Description:
This application is a continuation-in-part of pending U.S. Ser. No. 10/851,393 filed on May 21, 2004. 
    
    
     TECHNICAL FIELD  
      The field of this invention relates to a cleaning and honing device for polished concrete surfaces.  
     BACKGROUND OF THE DISCLOSURE  
      Normal cleaning of concrete whether by a power wash, power sweep or scrub progressively deteriorates concrete by breaking apart smaller particles from the concrete surface, thereby making the concrete surface more porous and more suspect to further deterioration.  
      Known cleaning brushes also progressively deteriorate concrete surfaces. The small bristles tend to undesirably add porosity to the concrete surface by poking into the holes that naturally occur in the concrete and breaking away the smaller particles of the concrete.  
      While concrete or cement is a very popular material for use in floors and construction materials because of its strength, durability and low costs, if the concrete or cement is left unfinished, the floor will inherently produce dust by the constant scuffing it undergoes whether by foot traffic or wheeled traffic and be susceptible to staining due to the porosity. One is then faced with a dilemma of cleaning a concrete floor with the disadvantage of the deterioration of its relatively smooth surface.  
      One way to achieve a better concrete surface look is to add a densifier such as sodium silicate to the concrete floor which closes the porosity of the floor. One then polishes the concrete with successive finer grit sand paper or polishing pads. This known process provides for a relatively attractive concrete polished surface. However this surface also needs maintenance when it gets dirty.  
      Previous attempts have been made to embed hardened abrasive particles such as silicone carbide a diamond particles into a substrate such as plastic for use on a power high speed machine. However, when such as abrasive device is used on the machine, the abrasive particles cause too much heat build up and has melted the plastic matrix. As more diamond particles are introduced in the plastic matrix, the more extensive and faster the heat build up occurs.  
      Previous attempts to embed hard diamond or other abrasive materials in the plastic matrix has resulted in affixing the diamond particles such that the diamond particle remains secured in the plastic even after the diamond edge has worn down and its abrasive cutting power has significantly degraded.  
      What is needed is a durable cleaning brush for mounting to a cleaning or buffing machine that is suitable for cleaning a polished cement floor. What is also needed is an expedient method to clean a polished concrete floor. What is also needed is a bristle that is durable and with a cross-sectional diameter larger than the cement floor pores in order to hone and smooth a concrete floor rather than degrade it during the cleaning process. What is also needed is a bristle that has a durable abrasive particle securely affixed to the bristle that is capable of honing a concrete surface.  
     SUMMARY OF THE DISCLOSURE  
      In accordance with one aspect of the invention, an abrasive cleaning device has a housing and a plurality of cleaning strips having a front abrasive face with a width and length. The cleaning strips are mounted to the housing such that the front abrasive face is aligned substantially transverse to the normal direction of motion of the housing. The cleaning strips include an abrasive material at the surface of the cleaning strips and secured to a substrate of the strips. The length of the face is substantially greater than the thickness of the strip to provide flexibility of the cleaning strips.  
      In accordance with another aspect of the invention, an abrasive cleaning device has a plurality of cleaning strips with one end mounted to the housing. The strip has a distal end with an abrasive material at the surface of a substrate and secured to the substrate. The length of the cleaning strips is substantially greater than its thickness to provide resilient flexibility. Preferably the substrate is made from a steel or plastic that provides the resilient flexibility to the bristle. Preferably, abrasive particles are secured to the strip such that when the strip wears it is exposing fresh abrasive particles at its working scrub surface. The distal working surface provides a flat edge to scrape away dirt and residue while the sharp abrasive particle cut and hone the cement surface. As the abrasive particles wear out, i.e. round down and loose its effectiveness, they eventually abrade away as the bristle shortens to expose new abrasive particles with sharp edges to the work surface.  
      In one embodiment, the abrasive material is formed by hard abrasive particles being embedded in the substrate that is a high temperature plastic matrix. In one embodiment, the housing is in the form of a rotatable pad made for rotation about a central point. The cleaning strips have their respective front faces substantially radially aligned with the center of the pad. In another embodiment, the housing is tubular and made for rotation about its major axis. The cleaning strips extend radially from the housing with the faces co-aligned with the major axis.  
      In accordance with another aspect of the invention, an abrasive bristle includes a plastic matrix, and an abrasive material embedded in only a distal end section of the bristle. A proximate mounting section of the bristle is devoid of the abrasive material. In another embodiment, the abrasive is coated on opposing ends. Preferably, the abrasive is brazed on the opposing ends.  
      In one embodiment, the distal end with the abrasive material extends toward the proximate mounting section with the abrasive ending at a point where the flexibility degrades a sufficient amount and the point being used as a wear indicator. In one embodiment, the abrasive material includes diamond particles. In one embodiment, the bristle includes abrasive material at opposing distal ends of the bristle element with a middle section being a mounting section to a support base. The middle section is devoid of the abrasive material. It is preferred that the abrasive material is embedded in the plastic matrix. It is also preferred that the plastic matrix is a high temperature plastic material.  
      In accordance with another aspect of the invention, a method of cleaning and honing a polished concrete surface includes moving a plurality of cleaning strips having a front abrasive face aligned substantially transverse to the direction of movement. The cleaning strips resiliently flex to accommodate high and low spots of the concrete surface. Preferably, the cleaning strip is in the form of a flexible plastic matrix with the abrasive face having a plurality of abrasive particle secured onto the cleaning strip across the face.  
      Preferably, the cleaning strips in cross-section have a major axis and a minor axis with the major axis positioned to be transverse to the normal motion of the housing. It is also preferred that the housing is a rotatable pad made for rotation about a central point. The cleaning strips have their respective major axis substantially radially aligned with the center of the pad. The minor axis is positioned to be transverse to the normal motion of the housing. In one embodiment, the abrasive material is diamond particles being brazed onto the substrate which can be steel.  
      According to another aspect of the inventor, the flexible bristles with abrasive particles have a cross-sectional diameter substantially greater than the cement pores and preferably greater than ⅛″ diameter to provide the bristles to glide over the pores and clean and hone the surface of the polished cement.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Reference now is made to the accompanying drawings in which:  
       FIG. 1  is a perspective view of a high speed burnishing brush with a cleaning device incorporating one embodiment of the invention;  
       FIG. 2  is an enlarged side elevational view of the cleaning device on the polished concrete floor;  
       FIG. 3  is an enlarged perspective view of one cleaning element made in accordance with another embodiment of the invention;  
       FIG. 4  is a cross sectional view taken along lines  4 - 4  shown in  FIG. 3 ;  
       FIG. 5  is an enlarged perspective view of a further modified embodiment of a cleaning element;  
       FIG. 6  is a cross sectional view taken along lines  6 - 6  shown in  FIG. 5 ;  
       FIG. 7  is an enlarged perspective view of an additional embodiment of a cleaning element;  
       FIG. 8  illustrates a method of attaching the bristle shown in  FIG. 7  to a housing;  
       FIG. 9  is a bottom plan view of a disc pad incorporating wide blade shaped strips in accordance with an alternative embodiment of the invention;  
       FIG. 10  is a perspective view of a roller brush incorporating blades in accordance with an alternative embodiment of the invention;  
       FIG. 11  is a cross-section side elevational view of a steel bristle with diamond abrasive particles brazed thereon in use on a concrete floor; and  
       FIG. 12  is a view similar to  FIG. 11  showing an embodiment with the abrasive particles only on the lower section of the front scrub face.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      Instead of washing and waxing as is often done with conventional floors, the maintenance of a polished concrete floor is accomplished by using an abrasive pad  32  used as shown in  FIG. 1  on a conventional high speed machine (not shown) for honing the concrete surface. The machine is set at about 175 rpm&#39;s with a pad pressure of 60-300 psi. The cleaning by honing can also be done by a drum brush  34  as shown in  FIG. 10  also mounted to a conventional drum machine (not shown).  
      The pad  32  is made from a plurality of cleaning elements called strips or bristles  36  which can be in the form of a round, square or rectangular bristle as shown in  FIG. 2  which can be embedded with abrasive  38 . The bristle  36  may be extruded from a high temperatures thermoplastic material mixed with abrasive particles  38 . The abrasive particles  38  may be a hard particulate such as alumina silicate or small industrial diamond particles.  
      In one embodiment as shown in  FIGS. 3 and 4 , the bristle  36  has a distal end  40  with an abrasive flat front face  39  that engages the polished floor  10  with the hardened abrasive particles. The abrasive particles are sufficiently aggressive to scour any dirt or grime that exists on the concrete floor. The square bristles are at least ⅛ inch wide to be larger than the pores of most normal concrete floors. The bristle is also flexible to flex over high spots of the concrete floor to avoid scratching of the high spots of the concrete surface. While a square bristle is shown, rectangular or other shaped bristles are possible as long as they have a scrub face  39  over ⅛ inch wide. In this fashion, the concrete surface is honed and not abraded or scratched.  
      The bristle has its mounted end  42  embedded in the pad as shown in  FIGS. 1 and 2  by being molded directly therein. The bristles are mounted such that the abrasive scrub face  39  is aligned transverse to the normal direction of motion of the pad at the face  39 . For example, as shown in  FIG. 9 , the faces  39  are radially aligned about the center  41  of the pad when the pad rotates about its center  41 . In this construction, all the bristles may be in working contact with the concrete surface simultaneously. The drum brush shown in  FIG. 10  has the faces aligned along the width of the drum brush such that as the drum rotates in the indicated direction, the face  39  flushly encounters the concrete floor.  
      When diamond particles  38  are embedded as abrasive in the bristle, it is desirable that only the working distal end  40  is provided with the diamond particles  38  to contain costs of the relatively expensive diamond particles. As shown in  FIGS. 3-6 , two embodiments are shown each with diamond abrasive in proximity with the distal end  40  and the proximate mounting end  42  being devoid of such diamond particles. The embodiment shown in  FIGS. 3 and 4  show a bristle with a layer of diamond particulates coated about the distal end. The diamond particulates are coated sufficiently thick and are secured strong enough to maintain its adherence to the underlying bristle material. It should be noted that only the scrub surface  39  needs to be coated. As shown, opposing surface  43  is also coated in case there are machines that rotate the pad in the opposite direction. The side walls  45  need not have any abrasive coating.  FIG. 12  illustrates an embodiment where only the front scrub surface  39  has an abrasive coating and the side walls  45  and opposing surface  43  are free of an abrasive coating. The diamond abrasive coating is positioned only at the distal section of the front scrub surface  39 .  
       FIGS. 5 and 6  show where the extruded bristle is made such that only the distal area  40  has the diamond particulate embedded therein with the remaining or proximate section  42  being devoid of diamond particulate. In this embodiment, the embedded diamonds extend completely through the interior of the bristle  36  as clearly illustrated in cross sectional view of  FIG. 6 . This embedded particulate has its advantages over the embodiment shown in  FIGS. 3 and 4  as the bristle abrades through extended use, its outer surface at the distal end  40  no matter how worn always provides an outer abrasive surface  39  with diamond particulate  38  on a working surface.  
      For either embodiment, as the pad  32  is used, the distal end  40  abrades to provide a straight knife-like edge  41  on the concrete surface  12 . As the diamond particles  39  wear down and their effectiveness becomes diminished, they eventually abrade off the bristle as the substrate material whether plastic or steel also wears down to provide a fresh diamond particles just above to replenish the effectiveness of the bristle for honing concrete surfaces.  
      Furthermore, the bristles  36  have a length that is sufficiently long compared to its thickness to provide resilient flexibility of the bristle as illustrated in  FIG. 2  to flex. As the bristle is shortened through the extended wear and the bristle becomes to short and too stiff for proper use, the diamond particulate also becomes exhausted which provides for a sensory indicator that the bush is worn out.  
      In this fashion an abrasive bristle maintains its abrasive aggressiveness for a long term. The resilient flexibility of the bristle provides relief when the pad hits a high spot of the concrete floor and will not gouge or scratch at the high spot or opens the pores at the high spot.  
      In this manner, the brush by having a bristle with a relatively wide, flat, and resilient flexible abrasive face  39  does not cause excessive deterioration or scratching of the concrete floor. In fact, it hones the concrete floor to maintain its smoothness. Secondly, by only having diamond particulate at the distal section  40 , there is less waste of diamond particulate and increases the structural and heat integrity of the plastic matrix. By placing the diamonds only on the front scrub face, the plastic matrix is able to withstand higher heat outputs produced by the diamond abrasive. By placing the diamond bristles in a rotating pad construction as shown in  FIGS. 1, 2 ,  8  and  9 , all the diamond scrub faces can be in operating contact with a concrete surface simultaneous thereby increasing the work output of the brush pad  32 . In addition, a sensory wear indicator is provided when the diamond particulate is totally abraded.  
      A further embodiment is shown in  FIGS. 7 and 8  which provides for a double ended bristle  46  that has two opposing distal ends  48  each with diamond particulate either coated or embedded in the same fashion as described in the embodiments shown and described for  FIG. 3-6 .  
      In this bristle, both distal ends  48  are positioned to be operable against the floor surface  10 . The mid-section  50  is mounted to the brush substrate by extending through holes  52  and being stapled in place by staple  54 . Other molding techniques may also embed the mid-section  50  in the brush with the two distal ends  48  extending outward. It should be noted that the bristle provides for two cleaning sections with opposing abrasive faces  39 . When the bristle is mounted into the pad, both faces  39  face the same direction. The operation of the brush bristles  46  is identical with the previous described embodiments.  
      While square cross-sectioned bristles  36  have been shown and described, wide blade bristles  36  as shown in  FIG. 9  can be used with pad  32 . Bristles  36  have a cross-section with a major and minor axis with the major axis being radially aligned about the center of rotation  41  and transverse to the normal motion of pad  32 . The blade shaped bristles  36  while shown in four staggered sections can have a variety of configurations on pad  32 . The bristles  36  may also have an elliptical or oblong cross-sectional shape with the major axis in the same position as shown. Other applications may have the minor axis aligned to be transverse to the normal motion of the housing. A bristle with a circular cross-section is also usable for honing the concrete surface if the diameter exceeds ⅛″.  
      While a plastic matrix has been shown and described, the substrate may be made from steel such as steel wire or wire strips  36  as shown in  FIG. 11  with diamond particles  38  brazed or electroplated thereon.  
      Another embodiment is shown in  FIG. 10  with drum  34  mounting wide blades  36  about its periphery to provide scrub faces  39  to operate in similar fashion as described before. The brush may also be used as an aggressive abrader. For this use, narrower bristles may also be used.  
      In all the shown embodiments, the wear of the substrate allows for the sacrifice of the diamond particles. Preferably, the diamond particles are sacrificed or fall off of the bristle before the diamond edge becomes sufficiently rounded. If the diamond edge becomes rounded, a ball bearing effect undesirably occurs where the diamond glides over the surface but does not cut, abrade or polish. By sacrificing the diamonds before hand, the bristle is assured to cut and hone as it wears down and becomes shorter.  
      In this fashion the use of diamond abrasive bristles becomes cost effective and provides for easy maintenance of a polished concrete or cement floor surface and provide honing of the floor during cleaning maintenance.  
      Other variations and modifications are possible without departing from the scope and spirit of the present invention as defined by the appended claims.