Precision contouring tool

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.

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.

DETAILED DESCRIPTION

Referring now toFIGS. 1-4, the precision contouring tool6is illustrated. Tool6is planar with a first face8, a second face10, a proximate end12, and a distal end14. Tool6is generally rectangular in outline, with first edge16, second edge19, first end edge21and second end edge23. All edges are square but can be rounded as illustrated inFIG. 10. Tool6is of uniform thickness (i.e. first face8and second face10are parallel). Tool6is 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:

CMnPSSiCrAl1.010.420.008.002.180.385.007
This specific composition and treatment along with the specific dimensions of length, width, and thickness, allow tool6to flex (elastically deform) as illustrated inFIG. 4, when pressure from a user's thumbs is simultaneously applied to proximate end12and distal end14of one face (either first face8or second face10, since precision contouring tool6, is reversible). The ability for tool6to flex is a necessity to achieving contour matching when contouring and shaping synthetic filler to a body panel. Tool6must 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. Tool6has the following dimensions (+/−5.0%): 0.062″ thick, 2″ wide, and 24″ long and coated in a replaceable polytetrafluoroethylene (PTFE) single sided tape18. Since the tool6will occasionally contact a jagged edge of a damaged panel the tape18will deform due to denting. However, small dents to tape18can actually be buffed or smoothed out by a plastic scouring pad. Should tape18tear, it can be easily replaced. Tape18is applied to spring steel17as a single sheet, which completely covers first edge16and second edge19, forming a seam25along the longitudinal axis of tool6on either first face8or second face10as is visible inFIG. 6. The PTFE has the following properties (+/−2%):

FIG. 5is an enlarged cross-sectional end view of the precision contouring tool6in which the layer of PTFE tape18is visible over the spring steel17. PTFE tape18provides a low friction/non-stick surface to contouring tool6, in which the synthetic filler will not easily adhere.

In operation, because of the flexibility of contouring tool6, the tool bridges dent20with its proximate end12and distal end14remaining in contact with body panel22on a first side24of dent20, and a second side26of dent20as can be seen inFIG. 6. The ability of contouring tool6to remain in contact with both sides24and26of dent20allows for the synthetic filler28to be contoured and shaped about to the damaged panel (i.e., dent20). The contour on each side24and26is transferred along dent20as the synthetic filler28is contoured and shaped, which is illustrated inFIG. 7. Since a car'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 filler28is applied in excess to the damaged (dented) part20of a body panel. Precision contouring tool6is brought in contact with an undamaged portion of body panel22, at an approximate angle of 20°-80° to body panel22. A user then applies pressure, via his thumbs, at both the proximate and distal ends12,14on first face8of tool6to match the contour of the undamaged portion of body panel22. The user then slides tool6across dent20. The tool6will remain in contact and match the contour of each side24and26of dent20, and will transfer that contour as it presses synthetic filler28into the dent20and pushes excess synthetic filler26ahead of it. During the slide of the tool6the 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 tool6may be achieved due to the synergistic effect of the specific spring steel used, the specific PTFE tape used, and the tool'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 panel22is not contoured, a stiffening bar30can be added to tool6as is visible inFIGS. 8 and 9. Stiffening bar30is comprised of an inelastic material, preferably carbon fiber or extruded aluminum and simply holds tool6via a friction fit. Stiffening bar30is circular in cross-section with a round hollow interior cavity32with two beveled retention members34, which form an inwardly tapered slot for frictional retention of tool6. When tool6is frictionally affixed to stiffening bar30, tool6remains rigid, and will not flex, allowing for the planar, smooth contouring and shaping of synthetic filler28, as may be found on the center of a car trunk. Additionally, since beveled retention members32are beveled, tool6can be used with stiffening bar30at very acute angles without stiffening bar30contacting the body panel.

Looking atFIG. 10, the application of synthetic filler28to flat body panel36can be seen. Synthetic filler28is applied in excess to the damaged (dented) part38of flat body panel36. Then, precision contouring tool6frictionally affixed to stiffening bar30is brought in contact with an undamaged portion of flat body panel36, at an approximate angle between 20°-80° to flat body panel36. A user then grips the proximate and distal ends12,14of tool6and slides tool6across dent38without exerting any pressure from the thumbs to arc the tool6. The tool6will remain in contact and match the flatness of each side40and42of dent38, and will transfer that flatness as it presses synthetic filler28into the dent38and pushes excess synthetic filler28ahead of it. Dent38is now contoured and shaped. The repair is smooth and uniform, restoring the original shape of body panel38.

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 tool6out 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'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 tool6beyond this range requires a considerable amount of thumb pressure. The amount of thumb pressure required to exceed the tool'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 tool6conform the contours of the area surrounding the dent. Tool6actually 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'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'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.