Resistance alters relative to direction of a thrust member (e.g., high resistance in one direction, low in the other):
(under subclass 266) Internal-resistance motion retarder wherein the restraining effort is responsive to the path of movement of a piston (first member), within a fluid, with respect to a chamber or cylinder.
(1) Note. In this subclass, a shock absorber retards movement of a mechanism in one direction with a normal force, but retards movement in an opposite direction with a greater or lesser force.
