# US 7,607,332 B2 · Apparatus for removing dent in sheet metal and method thereof

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- Number: US 7,607,332 B2
- Document ID: US7607332B2
- Status: Granted
- Kind: B2
- Application number: 11/870,701
- Filed: 2007-10-11
- Published: 2008-02-14
- Granted: 2009-10-27
- Earliest claimed: 2007-10-11
- Inventors: Beom-Seok Choe; Hoon Kim
- Web page: https://patentgrep.com/patent/US7607332B2

## CPC

- B23K 20/023: {Thermo-compression bonding}
- B23K 20/028: {Butt welding}
- C21D 1/42: Induction heating
- C21D 1/613: Gases; Liquefied or solidified normally gaseous material
- C21D 1/62: Quenching devices
- C21D 9/46: for sheet metals
- C21D 9/68: Furnace coilers; Hot coilers (cold coilers B21C47/00)
- C21D 11/00: Process control or regulation for heat treatments
- C21D 11/005: {for cooling}
- B23K 2101/18: Sheet panels
- Y02P 10/25: Process efficiency
- Y10S 72/705: Vehicle body or frame straightener
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B)
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

An apparatus for removing a dent in finished sheet metal heats a steel panel by applying a high frequency induced current thereto and simultaneously cools a clear coat by spraying a coolant to a surface of the sheet metal and a cooling pipe, wherein the finished sheet metal is composed of at least the ferromagnetic steel panel and the non-ferromagnetic clear coat having different thermal expansion coefficient and thermal damage temperature.

## Claims

### Claim 1

An apparatus for removing a dent in finished sheet metal, comprising:
a hollow housing;
a cylinder disposed in the housing;
a coil wound at an exterior circumference of the cylinder;
a cooling pipe disposed in the cylinder for supplying a coolant to the finished sheet metal and the cylinder;
an induced current generating module for applying a high frequency induced current to the coil, wherein a plurality of first air holes are formed at an exterior circumference of the cooling pipe along an axial direction thereof; and
a connecting body mounted in a lower portion of the housing, the connecting body having a plurality of second air holes and air grooves formed at a lower part of the connecting body.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein a nozzle is installed at an end of the cooling pipe for spraying the coolant to an exterior surface of the finished sheet metal.

### Claim 3 (depends on 1)

The apparatus of claim 1, wherein the cylinder further includes a cap for sealing air gap between the cooling pipe and the cylinder and is mounted in an upper end of the cylinder.

### Claim 4 (depends on 1)

The apparatus of claim 1, wherein a fan is mounted at an upper end of the housing.

### Claim 5 (depends on 1)

The apparatus of claim 1, wherein the induced current generating module further comprises a power supply and a display module.

### Claim 6 (depends on 1)

The apparatus of claim 1, wherein the coolant is liquefied carbon dioxide.

### Claim 7 (depends on 1)

The apparatus of claim 1, wherein the cooling pipe further includes a first switch for controlling supply of the coolant.

### Claim 8

A method for removing a dent in finished sheet metal, wherein the dent that is formed toward a steel panel is removed and where the steel panel is ferromagnetic and has a high thermal expansion coefficient and where the steel panel is coated at an exterior surface by a clear finishing coat that is non-ferromagnetic and has a low thermal expansion coefficient, and
wherein the steel panel is heated by applying a high frequency induced current thereto, and the clear coat is cooled by spraying a coolant from a plurality of first air holes formed at an exterior circumference of a cooling pipe along an axial direction thereof and a plurality of second air holes and air grooves formed at a lower part of a connecting body mounted in a lower portion of a housing.

### Claim 9 (depends on 8)

The method of claim 8, wherein heating of the steel panel and cooling of the clear coat are performed spirally from a border to a center of the dent.

### Claim 10 (depends on 8)

The method of claim 8, wherein the non-ferromagnetic clear coat is cooled by a coolant.

### Claim 11 (depends on 8)

The method of claim 8, wherein the coolant is liquefied carbon dioxide.