Machine parts, namely, couplings; shiftable and non-shiftable couplings; stiff, yielding and hydraulic couplings; gear couplings; friction couplings; articulate couplings and impulse couplings; free run units for use in drive systems; free run couplings; reverse run arrestors for use in drive systems; disc brakes; electric motors; engines; elastic machine parts made from polymers, metal or rubber for use in drive systems; motion dampers; shock absorbers; oscillation dampers; buffers for use i...