I-profile preform and an I-profile manufacturing method

An I-profile preform comprising:

• an outer wall of a first flange, and
• two inner walls of the first flange arranged in adjacent relation with respect to the outer wall of the first flange,
• a first web wall, wherein the first web wall extends perpendicular to the outer wall of the first flange, and
• a second web wall arranged in a plane parallel with respect to the first web wall,
• an outer wall of a second flange, wherein the outer wall of the second flange extends perpendicular to the plane,
• two inner walls of the second flange arranged in adjacent relation with respect to the outer wall of the second flange,
• wherein the walls are comprised of deformable sheet metal and are arranged in joined relation with respect to each other to provide in transverse cross-section a fluidly sealed closed empty inner space within the I-profile preform, and
• a valve element, wherein the valve element is arranged on one of the walls and is configured to enable fluid communication with the inner space through the valve element,
• wherein the walls of the first flange and/or the walls of the second flange, define at least one of a barrel shape and an hourglass shape in a longitudinal direction, wherein the longitudinal direction extends parallel to the plane.

An I-profile preform comprising:

• a first flange, wherein the first flange includes
• a first flange outer wall, and
• two first flange inner walls,
• a second flange, wherein the second flange is disposed away from the first flange and includes
• a second flange outer wall, and
• two second flange inner walls,
• a first web wall, wherein the first web wall
• extends perpendicular to each of the first flange outer wall and the second flange outer wall, and
• is engaged with one of the first flange inner walls and with one of the second flange inner walls,
• a second web wall, wherein the second web wall
• extends parallel to the first web wall,
• is engaged with the other of the first flange inner walls and with the other of the second flange inner walls,
• wherein the first flange, the second flange, the first web wall and the second web wall in transverse cross-section bound a hermetically sealed closed empty I-shaped inner space within the preform,
• wherein at least the first web wall, the second web wall, the two first flange inner walls and the two second flange inner walls are comprised of at least one deformable metal sheet,
• a fluid connector, wherein the fluid connector is configured to communicate metal sheet deforming fluid pressure to the inner space.

A method comprising:

• a) providing an I-profile preform including:
• an outer wall of the first flange, and
• two inner walls of the first flange arranged in adjacent relation with respect to the outer wall of the first flange,
• a first web wall, wherein the first web wall extends perpendicular to the outer wall of the first flange, and
• a second web wall, wherein the second web wall extends in a plane parallel with respect to the first web wall,
• an outer wall of the second flange, wherein the outer wall of the second flange extends perpendicular to the plane,
• two inner walls of the second flange arranged in adjacent relation with respect to the outer wall of the second flange,
• wherein the walls are comprised of deformable sheet metal and are arranged with respect to each other to provide a closed empty inner space within the I-profile preform, and wherein the walls of the I-profile preform have at least one unconnected wall edge,
• a valve element, wherein the valve element extends on one of the walls and is configured to enable fluid communication with the inner space through the valve element,
• b) sealing the at least one unconnected wall edge, wherein the closed empty inner space is hermetically sealed,
• c) operatively connecting a source of fluid pressure with the valve element,
• d) inserting the I-profile preform between pressure plates, wherein the pressure plates are in operative contact with the first flange and the second flange,
• e) subsequent to (b), (c) and (d), introducing fluid under pressure from the source into the inner space.