The object of the invention is a pulse heater for metals; this is a device used for spot pulse heating of a sheet metal, particularly of car bodies. It is conveniently used to fix damages and dents resulting from hail, vandalism or other potential phenomena. The invention belongs to class B21d 1/06 of the International Patent Classification.

The technical problem successfully solved by the present construction of the pulse heater for metals of the invention is smoothing of a hail-damaged or otherwise damaged metal, particularly of a car body, in which the paint/finish on the outer surface has not been damaged.

When a car body is hit or impacted by a hard object, this results in a small or big dent to be smoothed. It is important that the paint or finish has not been damaged and the pulse heater of the invention can be used to release the tensions that occurred on damaged spots, such that the dented metal reassumes its original condition without there being a need for repainting the entire surface of a car body during the repair of such damage.

Patent document WO2012/028636 discloses a universal tool for straightening and reshaping vehicle body damage by cold forming. The tool is composed of multiple extension elements that allow for calibration, the use of the tool set by means of individual tool extensions and the total length being optimized thereby. The described tool allows for a mechanical repair of a hail-damaged car body metal, yet damage of the paint/finish cannot be avoided and the car body needs to be re-painted/re-finished. Unlike the described cold forming by the hitherto known repair methods, the pulse heater for metals of the invention allows for thermal treatment of dents without damaging the finish on the external surface. When a dent is treated by the pulse heater for metals of the invention, the tensions get thermally released, wherein the structure of the metal does not change and re-assumes its original condition without the finish on the external surface of the car body getting damaged.

The pulse heater for metals of the invention that consists of a power transformer, a control electronic circuit, and a display of set intensity makes it possible that the current through a graphite handpiece“electrode +“ in contact with a dent site heats the material in spots and binds the microparticles of the graphite electrode with the exposed metal.

The invention will be explained in more detail on the basis of an embodiment and the belonging drawings, in which:

Figure 1 shows a block diagram of the pulse heater for metals of the invention;

Figure 2 shows a block diagram of the electronic circuit;

Figure 3 handpiece (electrode +) in cross-section;

Figure 4 handpiece (ground -) in cross-section.

The pulse heater for metals of the invention consists of a power transformer 1 inserted in a compact metallic housing, a control electronic circuit 2 and a display 3 of set treatment intensity. Output terminals a, b of the |

[BBI]2 are connected with the primary part of the power transformer 1 , while secondary terminals c, d of the power transformer 1 are connected by means of cables with handpieces 4, 5, with which repair is done. The output voltage on the terminals c, d of the power transformer 1 is displayed by means of the control electronic circuit 2 on the intensity display 3. The handpiece 4 is connected to the terminal c, while the handpiece 5 is connected to the terminal d. The handpiece 4 as the“electrode +" has a graphite electrode 8 inserted in a carrying portion 6 arranged in an insulated handle 7, said electrode being used to thermally treat a damaged dent. The handpiece 5 as the“ground has a permanent magnet 11 fastened in a metallic carrying portion 9 arranged in an insulated handle 10, said magnet ensuring a good contact with the car body without causing extra scratches or damages.

Once the pulse heater for metals is activated, the handpiece 5 with the permanent magnet 11 is placed in a direct vicinity of a dent on the car body, while the handpiece 4 is used to spot heat the metal on the site of the damage by contacting the electrode 8 with the damaged site and sliding over it. The tensions in the material thus get released which results in the dent popping out until the final straightened condition is reached without any finish damages. The heating intensity is adjustable by a potentiometer 12 and displayed on the display 3 of the set treatment intensity.

When the supply voltage of a normal sine waveform is turned on, the primary part of the power transformer 1 is supplied through the control electronic circuit 2, such that the intensity of the output signal from the control electronic circuit 2 on the terminals a, b changes as a function of the set value needed for the repair.

The control electronic circuit 2 is shown in the block diagram in Figure 2. It consists of a measuring/control section A, a supply section B and a regulation section C functioning as a signal converter. The control electronic circuit 2 provides for the fact that the primary voltage of the transformer 1 is not of a sine waveform yet of an identical frequency as the input sine, which means that the primary portion of the power transformer 1 is supplied in pulses with a precisely specified signal shape. The output terminals c, d of the transformer generate a signal that makes it possible that by using the handpieces 4, 5 the material is spot heated by the current through the graphite electrode 8 in contact with the car body metal at the dent site and binds the micro particles of the graphite electrode 8 with the exposed metal thanks to the output signal. This consequently means release of the tensions that occurred during the damage, hardening of the material and straightening of the damaged part of the car body, while the temperature does not reach the temperature that would damage the superficial layer of the finish, so re-finishing of the car body is not necessary.