1. Field of the Invention
The present invention relates to tools and other mechanisms that are used to remove dents from the surfaces of automobiles and other objects made of sheet metal. More particularly, the present invention relates to dent removal tools that are powered by pneumatic, hydraulic or electric motors.
2. Description of the Prior Art
Dent removal tools are commonplace in most automobile repair shops. Such tools are used to repair small dents in the exterior sheet metal of an automobile. Such dents commonly occur in automobiles for a variety of reasons. Those reasons include falling tree branches, hail stones, and impacts with adjacent car doors in a parking lot.
In the prior art, there are a variety of tools and techniques that are used to remove dents from sheet metal. If a sheet metal panel is accessible both above and below a dent, the most common technique for repairing the dent is through the use of a hammer and anvil. In this technique, a shaped anvil is placed above the dent. A hammer then strikes the metal from below the dent, thereby forcing the metal to conform to the shape of the above lying anvil. The hammer can be manually operated. However, to quicken the procedure, power operated hammers have been developed, such as is exemplified by U.S. Pat. No. 5,119,667 to Hollis, entitled Pneumatic Hammer Apparatus.
One of the advantages of the hammer and anvil dent removal technique is that the sheet metal is never pierced. Furthermore, the use of a hammer and anvil makes the dent in the sheet metal conform nearly perfectly to its original shape. Consequently, filler putty or solder need not be used to either smooth the dent or close a hole in the sheet metal.
In many applications, the area of sheet metal below a dent is not readily accessible. Accordingly, no conventional hammer or anvil can be placed below the dent. In such scenarios, dent pullers are commonly used. Dent pullers come in two major types. The first type is a contains a screw at its forward most tip and a sliding weight. To repair a dent, a hole is first drilled into the dent. The screw at the tip of the puller is then screwed into the hole. The slide weight is then moved reciprocally until the dent is pulled out of the sheet metal. Such screw tipped pullers are exemplified by U.S. Pat. No. 5,408,861 to McCain, entitled Dent Removing Pneumatic Puller and U.S. Pat. No. 3,922,902 to Jarman, entitled Dent Removal Device.
The second common type of dent pulling device does not have a screw tip. Rather, such devices have a welding tip that welds to the sheet metal in the area of the dent. Once the tip is welded to the sheet metal, the tip is pulled using a sliding weight. Such prior art devices are exemplified by U.S. Pat. No. 3,801,772 to Curcio, entitled In-Ding Repair Tool.
A problem associated with both major types of dent pullers is that the puller only attaches to one point of the dent at a time. As a result, the dent puller does not evenly deform the sheet metal. The result is that the dent must be pulled out to an inexact shape, The dent is then corrected by using a filler, such as fiberglass or solder. The dent is then sanded into its finished configuration.
The repairing of dents using fillers and sanding is not preferred because such repair techniques are labor intensive. Furthermore, any filler used to repair the dent may separate from the sheet metal in the future if the automobile exterior is ever again damaged by a collision or by weathering.
A need therefore exists in the art for a dent repair device that is capable of repairing a dent without the use of pullers and/or body filler, even when the underside of the dent is inaccessible. Such a need is met by the present invention as described and claimed below.