Active bolster with internal tear joints

An active bolster for an automotive vehicle, comprising:

• a base wall for mounting against a rigid structure of the vehicle;
• and
• a front wall overlying the base wall and forming an interior trim piece of the vehicle;
• wherein the base wall has a first surface facing the front wall, and the front wall has a second surface facing the base wall;
• wherein the base wall and front wall are comprised of molded plastic components, and the base wall and front wall are joined around a periphery to form an inflatable bladder with an initial open space between the first and second surfaces, wherein the bladder includes a plurality of tear joints;
• wherein each tear joint is comprised of first and second upstanding ribs, wherein the first upstanding rib is integrally formed with the base wall, extends from the first surface part way into the initial open space toward the second surface, and extends end-to-end substantially along a first direction, and wherein the second upstanding rib is integrally formed with the front wall, extends from the second surface part way into the initial open space to contact the first upstanding rib, and extends end-to-end substantially along a second direction that is substantially transverse to the first direction so that the first and second upstanding ribs contact at an intersection;
• and
• wherein at each intersection the first and second upstanding ribs comprise a welded joint that is substantially rigid against compression forces and that allows the tear joints to separate under tension during inflation of the bladder.