Telescoping energy absorber for vehicle bumper mounting - has two telescoping cylinders and pressure relief valve to control fluid flow and absorb impact

摘要

The energy absorber unit for vehicle bumpers has inner and outer telescoping cylinders with a pressure relief valve retained in a centralised opening in, or forming an integral part of the cylinder cap to control the flow of fluid between expandable fluid chambers in the unit. The valve capsule is load-sensitive and maintains a constant pressure so that unit stroke is proportional to impact velocity. With this construction, the corners of vehicle bumpers have a reduced swing arc as compared to velocity sensitive units, so that clearance between the bumper corners and vehicle body can be reduced. On rebound return springs force the fluid through the valve which, controlling the return fluid flow, reduces the rate of unit recovery.