Abstract:
A paint preparation tool, kit and method for preparing a previously coated surface by optionally mechanically removing loose coating material separated from the surface, applying a softening chemical to soften margin areas of the previously applied coating, and using a powered tool to rotate an abrasive disk against the surface to remove debris, dirt and oxides and to feather the edges of the remaining previously applied coating, where the abrasive disk may have a plurality of abrasive-impregnated elastomeric fingers extending generally perpendicularly from a disk-shaped support surface of the disk.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application is a division of application Ser. No. 10/870,793 filed Jun. 17, 2004, the entire contents of which are hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     A number of approaches to preparing previously coated surfaces for painting or staining are known. Typically paint is the coating to be removed, and as used herein, “paint” is to be understood to refer to any coating similar or identical to paint to be addressed in the process of preparing a surface for recoating, again typically using paint. Specifically, one other coating included within the meaning of “paint” as used herein is stain.  
         [0003]     Among the prior art paint removal approaches are powered devices such as a heat gun (for use with a putty knife or scraper), an infrared heat source sold under the name “Silent Paint Remover,” a rotary cutter sold under the name “Paint Shaver,” a rotary grinder sold under the name “Power Paint Remover.” In addition to powered products, manual products and processes have been known, such as carbide scrapers, chemical paint strippers, powered washers using a water stream of 1500 to 4000 psi at 2 to 4 GPM (with pressures at about 4000 psi needed to remove paint), and various sanding appliances, wire brushes and other such abrasives. As is also known, each of these prior art approaches have various shortcomings, including substantial manual effort, operator skill, potential damage to the substrate from which the paint is to be removed, and time.  
         [0004]     The present invention overcomes shortcomings of the prior art by providing an apparatus, kit and method that is easy, fast, convenient and economical to use. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]      FIG. 1  is a perspective view of a paint preparation tool useful in the practice of the present invention.  
         [0006]      FIG. 2  is an alternative embodiment of the tool of  FIG. 1 .  
         [0007]      FIG. 3  is a view similar to that of  FIG. 2 , except showing a user&#39;s hand grasping the tool.  
         [0008]      FIG. 4  is a view of a kit including the tool of  FIG. 1 , along with a paint softening chemical and applicator in the form of a paint brush.  
         [0009]      FIG. 5  is an alternative embodiment for the kit of  FIG. 4  with the paint softening chemical applicator in the form of a sprayer.  
         [0010]      FIG. 6  is a section view taken along line VI-VI of  FIG. 2 , showing various internal details of the paint preparation tool of the present invention.  
         [0011]      FIG. 7  is an exploded view of an assembly of a bristle disk, backing disk and attachment nut useful with the paint preparation tool of the present invention.  
         [0012]      FIG. 8  is a plan view of a front or bristle side of a bristle disk useful in the practice of the present invention.  
         [0013]      FIG. 9  is a section view of a surface in need of repainting, with paint chipped and peeling from the surface.  
         [0014]      FIG. 10  is a view of the surface of  FIG. 9 , except after mechanical removal of loose paint.  
         [0015]      FIG. 11  is a view of the surface of  FIG. 10 , except after application of a paint softening chemical.  
         [0016]      FIG. 12  is a view of the surface of  FIG. 11 , except after treatment according to the present invention and with the surface ready for repainting. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]     Referring to the Figures, and most particularly to  FIGS. 1 and 4 , the present invention includes a powered surface preparation tool  20  and kit  22  including the tool  20 , a conventional paint brush  24 , and a paint softening chemical  26 . In the preferred practice of the present invention, the brush  24  is used to apply the chemical  26  and the tool  20  is used to remove paint oxides and loose paint and feather the edges between bare substrate and well-secured old paint on the substrate. As used herein “substrate” refers to the surface previously coated or to be coated with paint or a similar protective coating material. An optional pre-treatment step is to remove loose peeling and chipped paint with a conventional putty knife or paint scraper. The tool  20  is preferably electrically powered, and utilizes an abrasive disk  28 , which may be similar to a bristle disc available from the 3M Industrial Business, 900 Bush Avenue, St. Paul, Minn. 55106, as a 4.5″ or 6″ bristle disc, UPC No. 24241-5 or 27675-4, except that the preferred bristle disk has a slightly softer elastomer composition and a special hub or mounting arrangement  30  specific to the tool  20 . Bristle discs which are the same or similar to disk  28  are described in U.S. Pat. No. 5,983,434, the entire contents of which are incorporated herein by reference. In the embodiment (shown in  FIGS. 6-8 ) disk  28  has a non-circular shaped aperture  30  and a specially configured mounting nut  31  to provide that the disk  28  is only used with the tool  20 . The tool  20  preferably operates the disk at a maximum speed of about 3000 RPM, with about 10 in-lb of torque when loaded against a surface to be treated. Optionally, a second, slower speed of about 1500 RPM may be made available in the tool  20 .  
         [0018]     Tool  20  has a guard  32  in the form of a curved flange (which may be extended further under a handle  36  if desired in an alternative embodiment, as indicated by chain line  33 ) to shield a hand of the operator grasping the tool by the handle  36  from contact with the disk  28 . In operation, the tool  20  is moved adjacent the surface to be treated, and bristles  38  of disk  28  are deformed by manual pressure of the tool  20  against the surface to be treated. Tool  20  also preferably has an ON-OFF switch  40  to energize the tool, rotating the disk  28  when the switch  40  is moved to the ON position.  
         [0019]     Tool  20  may optionally have an auxiliary handle  37  to allow two-handed operation. Auxiliary handle may be attached to tool  20  in a left-hand threaded recess  62  (shown in  FIG. 1 ), or a corresponding right hand threaded recess (as shown in  FIG. 2 ) or, optionally, there may be an inline threaded recess  64  for attachment of auxiliary handle  37  in line with main handle  36 .  
         [0020]     In an alternative embodiment shown in  FIGS. 2 and 3 , tool  20  may optionally include a strap or arch  66  to assist a user in holding the tool, as is illustrated in  FIG. 3 . Arch  66  may be permanently or removably secured to the tool using conventional techniques.  
         [0021]     Referring now also to  FIG. 6 , tool  20  also has a right angle gear drive  42  driven by an electric motor  44 , which is electrically connected in series with electrical contacts (not shown) within switch  40 . Tool  20  has an electric power cord  52  which is connected to a conventional plug (not shown). As shown, gearbox  42  is a two speed gear reducer switchable by way of a slide operator  46 . Operator  46  has a yoke or fork  70  interengaged with a groove  72  in a collar  74 . Collar  74  is free to slide axially along a shaft  76 , but is coupled to shaft  76  by a key  78  such that collar  74  will rotate with shaft  76 . Collar  74  has a plurality of pins or projections  80  that extend longitudinally of collar  74  and selectively engage collar  74  with one of bevel gears  82  or  84 . Each of gears  82  and  84  are journalled on shaft  76 . When pins  80  are positioned as shown in  FIG. 6 , pins  80  are engaged with gear  82 , causing an output drive member  86  to rotate at a first, higher speed, which preferably is about 3000 RPM. When slide operator  46  is moved to the right (as shown in  FIG. 6 ), collar  74  disengages pins  80  from gear  82 , and engages pins  80  with gear  84 , causing drive member  86  to rotate at a second, lower speed, preferably about 1500 RPM.  
         [0022]     Optionally, the right angle gear drive may have only a single speed, preferably about 3000 RPM. It is to be understood that each of gears  82  and  84  mesh with respective mating bevel gears  88  and  90 , each of which are coupled in a driving relationship with output drive member  86 . Output drive member  86  preferably has internal threads  92  to receive and mate with corresponding male threads  94  on mounting nut  31 .  
         [0023]     Motor  44  preferably has a splined output shaft  96  mating with a spur gear  98  affixed to shaft  76 . Motor  44  may also have a fan  100  and preferably has a pair of bearings  102 ,  104  supporting the armature or rotor  106  of the motor  44  in the housing  36 . Optionally, motor  44  may be a multiple speed or variable speed motor, if desired, used with a switching circuit or a conventional variable speed motor controller, if desired, to obtain the multiple speeds or variable speed.  
         [0024]     Referring now to  FIGS. 6, 7 , and  8 , certain details of the abrasive disk  28  and associated parts in a disk assembly  48  may be seen. Assembly  48  preferably includes the disk  28 , a backing plate  50  and the mounting nut  31 . Disk  28  preferably has a plurality of elastomeric fingers  56  forming bristles  38 , with abrasive particles embedded therein. The backing plate  50  is formed of relatively rigid material to support disk  28  and has a non-circular recess  54  to receive a non-circular shoulder  108  on nut  31 . Nut  31  may have a recess  110  with a hexagonal cross section sized to receive a conventional Allen or hex wrench (not shown) for installation and removal of the disk assembly  48  from the output drive member  86 . It is to be understood, however, that it is preferable to be able to install and remove the disk without the use of separate tools. In this aspect, the tool  20  may have a spring loaded locking pin, for example pin  34 , biased by a spring  35  away from a member of the drive train (the drive train including the motor  44 , the gear drive  42  and the output drive member  86 ), but selectively engageable with the member of the drive train to lock the drive train from rotation for installation and removal of the disk  28 . In the arrangement shown, pin  34  is manually engageable with one or more recesses or apertures  39  in a web of bevel gear  90 . Optionally, the pin  34  may be located elsewhere on the tool  20 . Disk  28  has a mating aperture  30  conforming to the non-circular shoulder  108 , to prevent disk  28  from turning with respect to output drive member  86 , once installed thereon. As may be seen in  FIGS. 7 and 8 , the non-circular configuration for aperture  30  and shoulder  108  is preferably a hexagon, but may be any other non-circular configuration suitable to resist relative rotation of disk  28  with respect to nut  31  and output drive member  86 .  
         [0025]     Referring now to  FIG. 5 , in an alternative embodiment  22 ′ of the kit, the paint softening chemical  26  may be supplied in a sprayable form, with a sprayer  58  and (optionally) a refill bottle  60  to replenish the sprayer with the chemical  26 . Although one form of manually operated sprayer  58  is shown, it is to be understood that other forms of sprayers (or other applicators, such as rollers) may be found useful in the practice of the present invention.  
         [0026]     The method of the present invention is directed to removing the chipped paint and provides a feathered transition between the substrate (which may be bare or may include substratum coatings below the outermost coating and which substratum coatings are well adhered to the substrate) and the remaining well-adhered (old outermost) paint on the substrate. The present invention is also directed to removing paint oxides which are apparent as a “chalky residue” on the previously painted surface. Finally, the present invention is directed to slightly abrading the surface, to provide “tooth” for improved adherence of a new paint coating to be applied after the practice of the present invention. As used herein, “tooth” refers to a slight surface texture created by abrasion in what would otherwise be a smooth non-porous surface.  
         [0027]     In one embodiment, a single speed tool is provided. In an alternative embodiment, a multi speed tool may be provided, in which for one aspect, a high speed setting may be used for large open areas to be treated, and in another aspect, a low speed setting is available for trim, molding and more detailed or delicate surfaces to be treated.  
         [0028]     The method of the present invention may include pre treating badly chipped and cracked surfaces by (optionally) mechanically removing the large, easy to remove paint chips from the surface to be treated. This may be accomplished using a putty knife or manual paint scraper. Next, the paint softening chemical is applied to the surface using a conventional paint brush or similar applicator. The paint softener is then allowed to act on the old paint, typically by waiting for about one hour. Next the powered tool is used to remove the paint oxides (chalky residue) from the surfaces having intact old paint. A pre-rinse with water may optionally be used at this time to act as a lubricant and to prolong the life of the bristle disk. One or two passes with the powered tool are used to remove the paint oxides. Next, the areas treated with the paint softening tool are re-wetted (if necessary), for example, using a garden hose. Wait about at least 3 minutes for the chemical to absorb the re-wetting water. The powered tool is then used to remove softened paint and to feather edges adjacent well adhered old paint, using 2 or 3 passes. Finally, the surface is washed down with water to remove any remaining softening chemical and debris from the previous surface preparation steps. After the surface is completely dry, it is ready to be repainted. It is to be understood that the present invention is directed to surfaces that have previously been coated with either latex or non-latex (e.g., oil-based) coatings.  
         [0029]     Referring now most particularly to  FIGS. 9-12 , a previously coated surface is shown (in a somewhat schematic fashion) before, during various stages of preparation according to the present invention, and as the surface appears after the practice of the present invention.  FIG. 9  shows a section view of a surface or substrate  112  in need of repainting, with an old coating of paint  114  shown as it would be in a condition chipped and peeling from the surface  112 . This view is intended to illustrate a typical condition of a weathered surface in need of repainting.  
         [0030]     Referring now to  FIG. 10 , as a first step (preferable, but not essential) the loose paint  116  from the previous coating is mechanically removed using a putty knife, paint scraper, wire brush or other similar paint preparation tool. It is to be understood that this step may be performed similarly to the way such a step has been performed in the prior art, except that less care need be taken in the performance of this step in connection with the present invention, since later steps of the method of the present invention will further and completely prepare the surface whether this step is carried out with care. The method of the present invention may be carried out even with the complete omission of this step, however to obtain the full benefits of the present invention, mechanical removal of loose paint is preferred. Once the loose paint is removed mechanically, the surface  112  will appear as shown in  FIG. 10 , typically with some of the old coating  114  remaining, often with a step-like transition  118  between the remaining old coating and a bare or uncoated region  120  of substrate  112 . Alternatively, one or more regions  120  may include well-adhered prior coatings (not shown) which were applied before coating  114 . Such a step-like transition is undesirable since it often remains as a visible topographical feature, even when coated with a new coating. For this reason, in the prior art, it was known to mechanically fair such transitions, using conventional techniques such as sanding. Alternatively, it was known in the prior art to use a chemical paint stripper to remove some, most or all of the old coating  114 . After use of a chemical paint stripper according to the prior art, it was sometimes still found necessary or desirable to sand the surface  112 .  
         [0031]     In the practice of the method of the present invention after the mechanical removal of loose paint, a coating  122  of the paint softening chemical  26  is applied as illustrated in  FIG. 11 , which is a view of the surface of  FIG. 10 , except after application of the paint softening chemical  26 . The paint softening chemical  26  is preferably a BACK TO NATURE G-4-1, most nearly similar to a BACK TO NATURE II product, each of which are produced by Back to Nature Products Co., Division of Dynacraft Industries Inc., at 28 Harrison Ave., Suite 238, Englishtown, N.J. 07726. The paint softening chemical  28  is similar to the BTN II paint stripper, except that it is weaker and has a surfactant and lubricant added to improve operation with the tool  20  in the practice of the present invention. The Material Safety Data Sheet for the BACK TO NATURE G-4-1 product lists the following ingredients:  
                                                           N.Methyl-2 Pyrrolidone   (872-50-4)   15-30%           Dimethyl Glutarate   (1119-40-0)   20-25%           Dimethyl Adipate   (627-93-0)   10-15%           Non Hazardous components       50-65%                      
 
 The paint softening chemical  26 , in a preferred form, is a gel-like substance which may be applied using the brush  24 . In use, it is applied as shown in  FIG. 11  and allowed to react with the old coating  114  for a predetermined period of time (a “softening dwell time”), typically about one half hour, it being understood that the material, condition and thickness of the old coating and the environmental conditions in which the present invention is practiced may indicate a different softening dwell time. Optionally, after the softening dwell time has elapsed, the surface may be wetted, to reactivate the chemical  26 , and to provide additional lubrication at the surface  112  to be contacted by the disk  28  in the operation of the tool  20 . 
 
         [0032]     Once the softening dwell time has elapsed (and the surface rewetted, if desired, e.g., in hot, dry environmental conditions) tool  20  is manually grasped and urged against surface  112  to remove coating  122  and any oxide on old coating  114 , and to feather each of the step like transitions  118  to a tapered transition  124 , as shown in  FIG. 12 . Optionally, once the surface  112  has been abraded using tool  20 , it may be rinsed, to remove any remaining chemical  26  and any loose debris.  
         [0033]     After treatment according to the present invention,  FIG. 12  illustrates a cross sectional view of the surface  112  ready for repainting, it being understood that the surface has been allowed to dry thoroughly before being ready for repainting.  
         [0034]     This invention is not to be taken as limited to all of the details thereof as modifications and variations thereof may be made without departing from the spirit or scope of the invention.