Patent ID: 7828331

Claim:
A variable load limiting device for a vehicle safety belt assembly for controllably restraining a vehicle occupant by the vehicle safety belt assembly during deceleration of a vehicle, the device comprising: a body including a first fluid chamber in selective communication with a second fluid chamber, each fluid chamber containing a free-flowing fluid therein wherein the body includes a cylindrical outer wall and a cylindrical inner wall, an inner surface of the inner wall at least partially defines the first fluid chamber, an outer surface of the inner wall and the outer wall at least partially defines the second fluid chamber, wherein a fluid passage is defined in the body via an opening in the inner wall, the fluid passage fluidly connecting the first and second fluid chambers; a wiper assembly operably disposed in the first fluid chamber and selectively coupled to the vehicle safety belt assembly, the wiper assembly creating a pressure differential within the first fluid chamber when a force in excess of a predetermined value is applied to the vehicle safety belt assembly; and a throttle valve operably connected to the body for controlling fluid pressure in the first fluid chamber, wherein the throttle valve is located in the fluid passage between the fluid chambers, the throttle valve controlling fluid pressure in the first fluid chamber by selectively allowing fluid flow between the fluid chamber and the second fluid chamber, the throttle valve opens to bleed fluid from the first fluid chamber to the second fluid chamber as the wiper assembly rotates and a drop in fluid pressure of the first fluid chamber allows fluid that was bled into the second fluid chamber back into the first fluid chamber.