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Link 1 is connected by turning pair A to the fixed link and by sliding pair B to link 2 which, in turn, is connected by screw pair C to the fixed link. Link 1 has a prismatic hole in which prismatic shank a of link 2 slides. Rotation of link 1 is converted into screw motion of link 2. When link 1 is turned through the angle ϕ₁, the displacement of link 2 along axis x-x is s₂=h_C(ϕ₁/(2π)) where h_C is the pitch of the thread in screw pair C. It is taken with a plus sign for right-hand thread and with a minus sign for left-hand thread.