Energy management damper

An expansible chamber energy management damper comprising a first cylinder having a head end and a rod end, a piston and piston rod reciprocable in the cylinder, a second cylinder having a head end and a rod end and surrounding the first and having its inside cylinder walls spaced from the outside cylinder walls of the first cylinder, the annular space between the two cylinder walls constituting a fluid reservoir, the two cylinders spaced apart axially at their head ends to provide a head chamber between them, fluid flow passages connecting said head chamber and said annular reservoir, at least two fluid flow passages in the piston for fluid flow through the piston, a check valve in one of said at least two passages to permit fluid to flow from the rod side of the piston, a check valve in the remaining one of said at least two fluid flow passages to permit fluid to flow toward the rod side of the piston, packing means in the rod end of the first cylinder to provide a fluid seal between the first cylinder and the rod which allows normal reciprocation of the piston and piston rod without fluid leakage past the rod to atmosphere, check valve means for permitting fluid flow from the rod side of the piston to the fluid reservoir, check valve means for permitting fluid flow from the head chamber into the first cylinder, means to conduct fluid between the space inside the first cylinder and the reservoir, and temperature responsive valve means normally closing the last-named fluid conducting means and openable when the fluid heats to a predetermined high temperature, whereby heating of the fluid to a potentially destructive temperature unloads the damper.