Seat with deployable plastic beam

An inflatable molded beam module 46 for a vehicle seat is mounted at a front of a seat (10, Fig.3), on top of a seat pan 18 and underneath a seat cushion (26, Fig.1). The module includes a molded plastic beam. The beam has a mounting flange 50 with a forward portion 52 and a rearward portion 54, with a gap 56 between said portions. A collapsible wall section 51 connects a cap portion 49 to the flange portion. In a deployed state, the wall sections are at least partially straightened, and in an undeployed state the wall section is collapsed to be substantially flat. When deployed, a seat cushion is displaced and deformed to raise the seat cushion when a frontal impact is detected. The seat pan may be manufactured from a carbon fibre reinforced composite, and the beam may be attached via ultrasonic welds.