Dent removal tool using rare earth magnets on probe tip to help locate tool tip
Kind Code:

“The dent removal industry utilizes specialized tools and techniques to remove automobile dents. This invention is unique because it uses strong magnet(s) attached to the tool tip introducing a magnetic field thru sheet metal. The magnetic material can be neodymium iron boron (NdFeB), samarium cobalt (SmCo), or other strong magnetic material. A magnetic dust applied on the painted surface of the sheet metal near the dent indicates the tips position. Sliding the tip on the underside of the sheet metal near the dust and dent collects the material at the tip's position. Identification of the tip's location reduces the number of pressure flexes, eliminates the need for specialized lighting, frees the technician's posture, and does not require extensive and costly training. This invention and technique greatly improves the ease, accuracy, and speed of removing dents. Untrained individuals can thus remove dents.”

Postma, Nerrit Scott (Parkville, MO, US)
Application Number:
Publication Date:
Filing Date:
Postma, Nerrit Scott (Parkville, MO, US)
Primary Class:
Other Classes:
72/31.01, 72/458
International Classes:
B21D1/12; B21D31/00
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Primary Examiner:
Attorney, Agent or Firm:
Scott Postma (Parkville, MO, US)
What is claimed:

1. Method of removing-dents from sheet-metal parts, in particular from painted parts of an automobile body using a tool with a magnetic tip to determine the tip's location and orientation. This invention has a magnetic material attached, on, in, or as the tip. The magnetic material can be either Neodymium Iron Boron (NdFeB), or Samarium Cobalt (SmCo) or other strong magnetic material. The tool tip maximizes the magnetic field (magnetic flux density) to the tip of the tool.

2. The user can easily locate the exact position of the tool tip by placing a small amount of magnetically active dust particles at or near the tips location but on the finished observable side of the sheet metal. The dust particles are magnetically-attracted to the closest attainable location of the tool tip. The dust particles can move with the movement of the tool. Once the exact location of the tool tip is identified and the tip is placed for optimal dent removal, the tool can be used in the customary fashion to remove the dent. Ordinarily, the act of placement of the tool tip is cumbersome and significant experience is necessary to place the tool tip at the desired point. The dust particles can be size range of 0.001 microns to 5 millimeters. This location technique allows the user to improve the ease of finding the tip.

3. The tips can be, but does not need to be, interchangeable from the tool, tool shaft, and/or tool handle. The magnetic tool tip can thus be removable and replaceable. The tips can have any number of attachment configurations. For example, female internal threads at the end opposite of the tip allows for the removal of the tip. The tool handle would then have male external threads to accept the different tips. A screw would allow the user to secure the tip at any of an infinite number of positions on the tool handle. The tips, having different l shapes, can perform the task of dent removal slightly differently. Some shapes work better for certain dent shapes. Interchangeability of the tips increases the tools versatility.

4. 4-12. (canceled)


In the autobody dent removal industry, dent removal tools are used to massage out sheet metal dents. One of the challenges to dent removal is placing the dent removal tool tip in exactly the correct location. To this end, knowing the tip location is essential. Previously, technicians learned how to determine the tip position by numerous hours of practice. This invention and technique greatly improves the ease of dent removal. In the industry's current method of removing dents from sheet-metal parts, the tip of the dent removal is placed (or inserted) onto the underside of the dented surface and in the area near the dent. The technician locates the tip by observing changes of reflected light from the topside of the sheet metal. When pressure is placed on the tool, the tip forces the sheet metal upward. By reading the light reflections, one can deduce the tip location and began the dent removal process. The technician places the tool tip in the center of the dent. The tool is repeatedly flexed. This flexing pushes the dent out of the sheet metal. Typically it takes numerous pressure flexes to remove the dent. Knowing the exact location of the tool tip is of paramount importance. Learning to remove dents usually requires specialized training. This invention utilizes a permanently magnetized tool tip to exactly locate the tool tip by observation of magnetically attracted particles on the top surface (tool user perspective side).

The magnetic material, including but not limited to, Neodymium Iron Boron (NdFeB), Samarium Cobalt (SmCo), Aluminum Nickel Cobalt (referred to as Alnico) or other strong magnetic material is located on, in, or as the tip of the tool. Rare earth magnets offer the unique advantage over conventional magnets due to their greater magnetic strength, thus the magnetic field lines can saturate the sheet metal and sufficiently transfer through to attract magnetically active bearing particles. Any strong magnetic material, or combination thereof, could be used as the magnetic material on, in, or as the tool tip, or, the observing media. The tool tip is ideally designed with a shape to incrementally reshape the sheet metal to its original shape while simultaneously optimized for magnetic density at the tip for the purpose of collecting observable particles on the opposite side of the sheet metal. The tool can be designed to optimize magnetic density at the tip by, for example, but not limited to, having a spherical rare earth magnet attached and aligned at the tool tip end with the magnetic field lines oriented with the tool so that the tool touches the metal with the magnetic maximum flux point. As a different configuration example, the tool tip could have an imbedded magnet and the tool material at the tip surrounding or in close proximity to the magnet made of a non magnetic material stainless steel. Thus the design optimizes the magnetic flux at the tool tip for transferring magnetic field lines through the sheet metal when touching the auto body. A small amount of magnetic particles (paramagnetic or magnetic particles having the approximate size range of 0.001 to 5 millimeters, approximately), on the other side of the sheet metal from the tool tip, is magnetically attracted and accumulates at the exact opposite side of the sheet metal from the dent removal tool probe tip. The dust can stick to the outside of the sheet metal without the aid of the magnet because the particles can be magnetized. Iron particles could be as simple as a by-product from a metal grinder or as sophisticated as coated particles that have rounded shapes (minimal sharp edges on the particles surface) that would not damage a painted surface. Once the tool tip touches or comes close to touching the metal, the particles collect at the closest point to the probe tip on the other (finished) side of the sheet metal. The particles show the user where the exact position of the tool on the other side of the sheet metal. This technique is also much quicker than the previous art in locating the probe tip. Additionally, this technique helps to locate the probe tip when the tip is in a location in or around a dent where the plane of the metals surface distorts the metal surface making locating the tool tip by light reflection difficult. After the tool tip is located, then the tool can be used as is customary to remove the dent. Additionally, this invention could have removable tool tips from the tool shaft, but the tips do not, necessarily, need to be removable to accomplish the primary aspect of the invention.

This objective is achieved with the characteristics given in claim 1 and 2 and with respect to the apparatus by an arrangement with the characteristics given in claim 3.

In a preferred embodiment of the method, that a permanent magnetic field is produced by means magnetic material. The magnetic material must be strong enough to penetrate the metal. Rare Earth elements are the preferred magnetic material. These include, but are not limited to, material like Neodymium Iron Boron (NdFeB), Samarium Cobalt (SmCo), Aluminum Nickel Cobalt (referred to as Alnico) or ceramic permanent magnetic material.

Advantages and useful features of the invention will additionally be apparent from the subordinate claims and from the following description of exemplary embodiments with reference to the figures, herein.

The removal of dents from pieces of sheet metal with the aim of restoring, as far as possible, an original (flat or curved) shape is a task that occurs in many branches of industry and the trades. Although a large number of technical procedures and devices have been developed to accomplish this task, some of which are commercially available, the problem is still often solved by the manual efforts of trained personnel. This entails considerable expense. The learning or training of workers to be able to locate the tool tip is a significant challenge. This tool greatly assists the worker in locating the tool tip without the typical expertise needed without the tool. Observing a small pile of magnetic particles located at the exact location of the tool tip on the opposite side of the sheet metal is substantially easier than locating the tool tip on the opposite side of a piece of sheet metal by observing the changes in light reflection when the tool is flexed against the metal.

The tool also has the advantage of not requiring the worker to flex the sheet metal to cause light reflection distortions for the purpose of locating the tool tip. This procedure only requires that the tool tip be placed on the metal near the dent and magnetic particles to be dusted on the opposite side of the sheet metal. The particles will congregate near the probe tip and easily and exactly identify the location of the tool.

The tool also has the advantage over current methods because the probe tip is magnetized. This has three distinct advantages; 1) this allows the tool to have a larger static coefficient of friction between the tool tip and the sheet metal. A larger coefficient means less possibility of the tool tip sliding when pressure force is applied to work out the dent. A sliding tool tip can cause substantial damage to the plane of the surface. 2) A magnetic tip allows the user to free his hands from the tool, without the tool tip relocating to an undesirable location. 3) A magnetic tip holds the particles in position on vertical surfaces. This technique does not necessarily need a direct light source in order to locate the probe tip. While a light would still be desired for closer, more finite, observation of the dent, direct reflected light from a light source is not essential.

Some embodiments are within the scope of those skilled in the art and hence are not described in greater detail here.

The invention can be put into practice not only by the embodiment described above, but also by a large number of modifications thereof.

FIG. 1 and FIG. 2 show the ordinary tool, in this case a 45 degree bend tool. Many other angles are available and FIG. 1 and FIG. 2 only show one example. Since numerous tip sizes, lengths, configurations, and shapes of the tool probe tips are needed due to different sizes, shapes, and locations of dents, the tips on the tool can be removable and interchangeable. This allows the user the most flexibility in the art of dent removal.

FIG. 3 and FIG. 4 show a different arrangement of the tool tip. In this example of a 45 degree bend tool, the spherical head is magnetic. FIG. 3 and FIG. 4 would not be a removable interchangeable tip since no detachment device is incorporated. The magnetic material is not annotated. The spherical head is the magnetic material. FIGS. 1 through 4 are only a few of the potential arrangements. The novelty of the invention is not necessarily the tip shape, size, or design, but that the magnetic material is attached, on, or in the probe tip allowing for particle collection on the opposite side of the metal for ease of tip location. The art contained herein is not limited by the tip design.