A damped mechanical joint assembly comprises two damping members, a joint body positioned therebetween and rotatable relative thereto; and a retainer for maintaining engagement of the damping members with opposite damping surfaces of the joint body. The joint body is provided with a plurality of damping cylinders positioned around the joint rotation axis in a uniformly angularly spaced circular pattern, and each damping cylinder comprises a pair of piston chambers, each opening onto opposite damping surfaces, and a constricted passage connecting the piston chambers. Each of the piston chambers is provided with a piston assembly slidably positioned therein, and each damping cylinder is filled with fluid between the piston assemblies. Each damping member is provided with a circular groove comprising a plurality of uniformly angularly spaced ramped depressions separated by groove barriers. The number of damping cylinders preferably differs from the number of depressions by at least two. The fluid in the damping cylinders urges each piston assembly into engagement with the groove of the corresponding damping member, and the damping members are positioned so that when a piston assembly is located within a ramped depression of the groove of one damping member, the corresponding piston assembly is located at a groove barrier of the groove of the other damping member, thereby resulting in reciprocating motion of the piston assemblies and concomitant flow of the fluid though the constricted passage of the damping cylinders as the joint body rotates relative to the damping members. Viscous resistance to flow of the fluid through the constricted passage as the joint body rotates causes the piston assembly to be urged more strongly into engagement with one of the ramped depressions, thereby producing a damping torque opposing rotation of the joint body, the damping torque increasing with increasing angular velocity of the joint body.
