Patent Abstract:
Cold rolled, annealed, blue tempered spring steel and high density polytetrafluoroethylene are combined and specifically gauged, sized, and edged to form a precision contouring tool capable of shaping, contouring, and controlling the movement of synthetic fillers on damaged auto body panels, resulting in a perfectly shaped repair. For application involving flat panels a stiffening bar is frictionally fitted to the precision contouring tool.

Full Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to auto body tools. More particularly, the present invention relates to a precision contouring tool for the contouring and shaping of synthetic fillers to repair damaged body panels on vehicles. 
     In the past automobile body panels were constructed from heavy gauge metals, and often these panels were flat or nearly flat. Repairing a damaged panel was an iterative process in which a synthetic filler was applied in excess to the panel and then the excess material was cut away using a removal tool, such as a sander or rasping plane, and eventually transitioning to a fine grit sandpaper. It would not be unusual to miss a spot or realize there are some gaps or pits in the filling of the damage after the first application of filler. A new batch of filler would have to be applied and the process repeated until most of the filler was removed, resulting in smooth transition between the metal and filler. 
     Today, body panels are composed of light-weight metals, are extremely thin, and contain contoured body lines which extend over several panels appearing contiguous over the length of the automobile. When a panel is damaged, these thin, irregularly shaped panels, are extremely hard to fill accurately, often resulting in a “fix” that simply does not match the original contour. What was a painstaking process in the past is presently even more labor intensive, and typically reserved for auto body repair professionals. 
     SUMMARY OF THE INVENTION 
     In accordance with the invention, the countless hours of sanding to shape synthetic fillers that have been applied in excess to the damaged portion of an auto body panel is solved by a precision contouring tool that allows a minimal amount of pressure to be applied while controlling the movement and placement of the synthetic plastic filler during its contouring and shaping. The shaping and contouring of the filler occurs simultaneously thus requiring only a minimal amount of light sanding to finish. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of the precision contouring tool; it should be noted that the back view is identical to the front view; 
         FIG. 2  is an end view of the precision contouring tool; both right and left end views are identical; 
         FIG. 3  is a top view of the precision contouring tool; 
         FIG. 4  is a front view of the precision contouring tool in a flexed state; 
         FIG. 5  is an enlarged cross-sectional end view of the precision contouring tool; 
         FIG. 6  illustrates the precision contouring tool bridging the damaged portion of an auto body panel; 
         FIG. 7  illustrates the precision contouring tool in a flexed state contouring and shaping synthetic filler over a damaged portion of an auto body panel; 
         FIG. 8  is an end view of the precision contouring tool, featuring a stiffening bar; 
         FIG. 9  is a perspective view of the precision contouring tool, featuring a stiffening bar; and 
         FIG. 10  illustrates the precision contouring tool, featuring a stiffening bar, contouring and shaping synthetic filler over a damaged portion of an auto body panel. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to  FIGS. 1-4 , the precision contouring tool  6  is illustrated. Tool  6  is planar with a first face  8 , a second face  10 , a proximate end  12 , and a distal end  14 . Tool  6  is generally rectangular in outline, with first edge  16 , second edge  19 , first end edge  21  and second end edge  23 . All edges are square but can be rounded as illustrated in  FIG. 10 . Tool  6  is of uniform thickness (i.e. first face  8  and second face  10  are parallel). Tool  6  is made from the ASTM 1095 carbon steel family. The preferred embodiment is cold rolled, annealed, and blue tempered into a spring steel with a Rockwell hardness of HRC 48-51. It has the following specific chemical analysis: 
                                                     C   Mn   P   S   Si   Cr   Al                   1.010   .420   .008   .002   .180   .385   .007                    
This specific composition and treatment along with the specific dimensions of length, width, and thickness, allow tool  6  to flex (elastically deform) as illustrated in  FIG. 4 , when pressure from a user&#39;s thumbs is simultaneously applied to proximate end  12  and distal end  14  of one face (either first face  8  or second face  10 , since precision contouring tool  6 , is reversible). The ability for tool  6  to flex is a necessity to achieving contour matching when contouring and shaping synthetic filler to a body panel. Tool  6  must be able to flex to form various, even radius curves with only minimal or moderate pressure so the required arc can be maintained evenly over an elongated surface area without any change. Tool  6  has the following dimensions (+/−5.0%): 0.062″ thick, 2″ wide, and 24″ long and coated in a replaceable polytetrafluoroethylene (PTFE) single sided tape  18 . Since the tool  6  will occasionally contact a jagged edge of a damaged panel the tape  18  will deform due to denting. However, small dents to tape  18  can actually be buffed or smoothed out by a plastic scouring pad. Should tape  18  tear, it can be easily replaced. Tape  18  is applied to spring steel  17  as a single sheet, which completely covers first edge  16  and second edge  19 , forming a seam  25  along the longitudinal axis of tool  6  on either first face  8  or second face  10  as is visible in  FIG. 6 . The PTFE has the following properties (+/−2%):
 
     
       
         
               
               
               
               
               
             
           
               
                   
               
               
                   
                 Adhesive 
                   
                 Tensile 
                   
               
               
                 Thickness of 
                 Thickness 
                 Adhesive 
                 Strength 
               
               
                 tape (inches) 
                 (inches) 
                 Type 
                 (lbs/in) 
                 Elongation % 
               
               
                   
               
             
             
               
                 0.0122 
                 0.0022 
                 Silicone 
                 33 
                 250 
               
               
                   
               
             
          
         
       
     
       FIG. 5  is an enlarged cross-sectional end view of the precision contouring tool  6  in which the layer of PTFE tape  18  is visible over the spring steel  17 . PTFE tape  18  provides a low friction/non-stick surface to contouring tool  6 , in which the synthetic filler will not easily adhere. 
     In operation, because of the flexibility of contouring tool  6 , the tool bridges dent  20  with its proximate end  12  and distal end  14  remaining in contact with body panel  22  on a first side  24  of dent  20 , and a second side  26  of dent  20  as can be seen in  FIG. 6 . The ability of contouring tool  6  to remain in contact with both sides  24  and  26  of dent  20  allows for the synthetic filler  28  to be contoured and shaped about to the damaged panel (i.e., dent  20 ). The contour on each side  24  and  26  is transferred along dent  20  as the synthetic filler  28  is contoured and shaped, which is illustrated in  FIG. 7 . Since a car&#39;s exterior is a plethora of changing compound curves the ability for the tool to mimic these geometric proportions based on the contour of the undamaged area surrounding the dent is what can dramatically shorten the time it takes a bodyman skilled with the tool to repair a vehicle. In use, a synthetic filler  28  is applied in excess to the damaged (dented) part  20  of a body panel. Precision contouring tool  6  is brought in contact with an undamaged portion of body panel  22 , at an approximate angle of 20°-80° to body panel  22 . A user then applies pressure, via his thumbs, at both the proximate and distal ends  12 ,  14  on first face  8  of tool  6  to match the contour of the undamaged portion of body panel  22 . The user then slides tool  6  across dent  20 . The tool  6  will remain in contact and match the contour of each side  24  and  26  of dent  20 , and will transfer that contour as it presses synthetic filler  28  into the dent  20  and pushes excess synthetic filler  26  ahead of it. During the slide of the tool  6  the user increases or decreases the pressure that his thumbs exert to maintain planar contact with the contoured periphery of the dented area. This allows for smooth transitions between the different geometric contours of the area under repair. Full replication of a compound curved body panel with the tool  6  may be achieved due to the synergistic effect of the specific spring steel used, the specific PTFE tape used, and the tool&#39;s dimensions. The precision contouring tool can be used over and over again without suffering from metal fatigue or work hardening. 
     For flat applications, i.e., where the body panel  22  is not contoured, a stiffening bar  30  can be added to tool  6  as is visible in  FIGS. 8 and 9 . Stiffening bar  30  is comprised of an inelastic material, preferably carbon fiber or extruded aluminum and simply holds tool  6  via a friction fit. Stiffening bar  30  is circular in cross-section with a round hollow interior cavity  32  with two beveled retention members  34 , which form an inwardly tapered slot for frictional retention of tool  6 . When tool  6  is frictionally affixed to stiffening bar  30 , tool  6  remains rigid, and will not flex, allowing for the planar, smooth contouring and shaping of synthetic filler  28 , as may be found on the center of a car trunk. Additionally, since beveled retention members  32  are beveled, tool  6  can be used with stiffening bar  30  at very acute angles without stiffening bar  30  contacting the body panel. 
     Looking at  FIG. 10 , the application of synthetic filler  28  to flat body panel  36  can be seen. Synthetic filler  28  is applied in excess to the damaged (dented) part  38  of flat body panel  36 . Then, precision contouring tool  6  frictionally affixed to stiffening bar  30  is brought in contact with an undamaged portion of flat body panel  36 , at an approximate angle between 20°-80° to flat body panel  36 . A user then grips the proximate and distal ends  12 ,  14  of tool  6  and slides tool  6  across dent  38  without exerting any pressure from the thumbs to arc the tool  6 . The tool  6  will remain in contact and match the flatness of each side  40  and  42  of dent  38 , and will transfer that flatness as it presses synthetic filler  28  into the dent  38  and pushes excess synthetic filler  28  ahead of it. Dent  38  is now contoured and shaped. The repair is smooth and uniform, restoring the original shape of body panel  38 . 
     After contouring and shaping of a synthetic filler to a damaged body panel often excess filler will remain on the precision contouring tool. After the synthetic filler dries it can be simply removed from the tool via a plastic scouring pad or blown clean via an air hose. 
     Making the tool  6  out of a carbon steel treated and sized as described above imparts a certain “feel” and “memory” for arcing the tool to mimic most of common arcs of its working range which lie in the 1/16 to 1 inch range as measured between the lower edge of the tool at the tool&#39;s longitudinal center and a plane drawn between the distal and proximate tool ends. This is learned quite quickly. The force required to arc the tool  6  beyond this range requires a considerable amount of thumb pressure. The amount of thumb pressure required to exceed the tool&#39;s working range makes the tool vibrate slightly (that the user can feel) and thus leaves a wavy trail of synthetic filler that is clearly visible and requires additional sanding. Thus, the specific dimensional configuration and mechanical properties of the preferred embodiment tool accomplish an unexpected synergist effect that allows the tool to be self limiting or at least able to give the user physical and visual clues that he is out of the working range. This is important as not all bodymen have the eyesight to be able to make the tool  6  conform the contours of the area surrounding the dent. Tool  6  actually sees or feels the contour. 
     A first alternate embodiment is a thinner version and therefore to achieve the same self limiting effect with the same steel, has the following dimensional properties (+/−5%): 0.05″ thick, 2″ wide, and 24″ long. The first alternate embodiment is perfect for moderately cured areas such as quarter panels, liftgates, and, fenders, etc., where the working range is in the 1.25 inches to 2 inches range as measured between the lower edge of the tool at the tool&#39;s longitudinal center and a plane drawn between the distal and proximate tool ends. 
     A second alternate embodiment is yet an even thinner version than the first alternate embodiment with the following dimensional properties: (+/−5%): 0.042″ thick, 2″ wide, and 24″ long and perfectly suited for the contouring of highly curved surface areas such as hoods, where the working range is in the greater than 2 inches range as measured between the lower edge of the tool at the tool&#39;s longitudinal center and a plane drawn between the distal and proximate tool ends. 
     The above description will enable any person skilled in the art to make and use this invention. It also sets forth the best modes for carrying out this invention. There are numerous variations and modifications thereof that will also remain readily apparent to others skilled in the art, now that the general principles of the present invention have been disclosed. As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.

Technology Classification (CPC): 1