Patent ID: 7234335

Claim:
Method for producing head elements for heaters comprising the steps of: preparing a piece of a sheet metal ( 1 ); deep drawing said sheet metal piece ( 1 ) to obtain a hollow molded piece ( 2 ), defined by a base wall ( 3 ), sides ( 4 , 5 , 14 , 15 ) joined to and surrounding the base wall and forming an open side ( 6 ); cutting the sides ( 4 , 5 , 14 , 15 ) along the open side ( 6 ), to define a hollow body ( 8 ) with an edge ( 9 ), which is uniform and extends around said open side ( 6 ); making a lateral through aperture ( 12 ) on two opposite sides ( 4 , 5 ) of the hollow molded piece to obtain apertured opposite sides; providing fastening means ( 25 ) around each lateral through aperture ( 12 ) made on the hollow molded piece; making at least one notch ( 16 ), on the apertured opposite sides ( 4 , 5 ), along said edge ( 9 ); introducing at least two cylindrical cores ( 18 ) into said edge ( 9 ) of said apertured hollow molded piece in matching areas ( 19 ) without said at least one notch ( 16 ); stamping a flange ( 17 ) for extending around each of said at least one notch and between said cores ( 18 ), so as to close the sheet metal around said cores ( 18 ) and in the area of said edge ( 9 ), thus widening said notches ( 16 ) and forming circular holes around the cylindrical cores; removing said cores ( 18 ) from the hollow body; welding said edge ( 9 ) along said flange ( 17 ) of said widened at least one notch ( 16 ), so as to obtain a series of holes ( 21 ) separated from each other; the fastening means ( 25 ) provided on each lateral through aperture ( 12 ) by pressing outwards a circular crown ( 27 ), extending around each lateral through aperture ( 12 ), so as to form a protruding edge ( 31 ) on each of said apertured sides ( 4 , 5 ).