Patent ID: 8464570

Claim:
A method of forming S-shaped folded edges on a heat-insulating protective metal component comprising the following steps: placing a first metal base plate ( 1 ) to form an upper layer, a second metal base plate ( 2 ) to form a lower layer, and heat-insulating materials ( 3 ) in between the upper layer and the lower layer to form a middle layer; and then fixing the first and the second metal base plates ( 1 , 2 ) with the heat-insulating materials ( 3 ); stamping the first and the second metal base plates ( 1 , 2 ) to form J-shaped edges ( 4 ), where the J-shaped edges ( 4 ) of the first and the second metal base plates ( 1 , 2 ) are perpendicular to a horizontal portion of the first and the second metal base plates ( 1 , 2 ) and each of the J-shaped edges ( 4 ) has an outwardly bent curve with a crown ( 5 ) and an end ( 6 ); using an upper mold (M 1 ) which consists of a concave surface and a flat surface to press against a lower mold (M 2 ) which consists of another flat surface to exert lateral force onto the ends ( 6 ) of the J-shaped edges ( 4 ) so that the J-shaped edges ( 4 ) of the first and the second metal base plates ( 1 , 2 ) inwardly bend towards the first metal base plate ( 1 ) which forms the upper layer; continuing in pressing the upper mold (M 1 ) downward so that a horizontal flat surface of an edge pressing part of the flat surface of the upper mold (M 1 ) exerts vertical force to the crowns ( 5 ) and compresses the J-shaped edges ( 4 ) into S-shaped bent folded edges.