OCCUPANT RESTRAINT SYSTEM

摘要

A vehicle includes an energy absorbing bumper system having an impact bar supported by like spaced pairs of telescopic energy absorbing struts. Each strut includes an inner member having an outer closed end secured to the impact bar and an outer member secured to the frame of the vehicle. An apertured end cap on the open inner end of the inner member provides a piston slidably received within the outer member and cooperating with the outer closed end of the outer member to provide a variable volume first chamber receiving a displaceable pressurized fluid medium such as Freon or other gas liquefied under pressure at ambient temperatures. A piston slidably received within the inner member divides the interior thereof into a variable volume second chamber receiving pressurized compressed gas to provide a gas spring biasing the inner member and impact bar outwardly of the outer member. A normally closed valve in the outer closed end of the outer member includes a metering pin received within the aperture of the end cap to provide a variable area orifice controlling the rate of flow of the fluid medium between the first and second chambers under impact forces applied to the impact bar to absorb the energy of such forces. An inflatable occupant restraint cushion is mounted within the occupant compartment of the vehicle and communicated with the valves in the outer closed ends of the outer members. When the inner members move within the outer members under impact forces applied to the impact bar, the fluid medium is displaced from the first chambers to the second chambers through the variable area orifices after the pressurized gas in the third chambers is initially compressed. The area of the orifices is gradually decreased by the metering pins as the inner members move within the outer members to pressurize the first chambers and absorb the energy of the impact forces. Should the impact forces exceed a predetermined limit, the inner members will move within the outer members to a position wherein the pistons of the inner members engage their respective metering pins and open the valves to permit the flow of the fluid medium to the inflatable cushion to inflate the cushion. The fluid medium expands to a vapor as it flows to the cushion.