Air bag with flexible tensioning means

An air bag arrangement, in particular an air bag located to the side of a vehicle, comprises an inflatable air bag 4 associated with an inflator 5 which generates gas to inflate the air bag. The gas enters an elongate diffusor 8 provided with apertures 9 in the side wall thereof. The arrangement further comprises an element 10 adapted to move in response to the generation of gas by the inflator to apply tension to an elongate flexible element 11 to raise part of the inflatable element to an operative position. The movable element 10 may be a piston located in the diffusor wherein gas is allowed to enter the air bag through the apertures in the diffusor as the piston travels along the diffusor. In another embodiment (see figure 4) the movable element may be a turbine wheel acted upon by the gas so as to wind in the flexible element.