The lengths of the links comply with the condition: A͞B = D͞C. Cranks 1 and 2 rotate about fixed axes A and D. At points B and C the cranks have rollers a and b which slide and roll in the slots d of double slotted link 3. Slotted link 3 turns about fixed axis E of slider 4 which can be adjusted and rigidly clamped in fixed guide p by screws e. The rotation of driving crank 1 is transmitted through rollers a and b, and slotted link 3 to driven crank 2. In the position shown, the distance A͞E = E͞D. In this case, rotation is transmitted from link 1 to link 2 wi th the constant transmission ratio i₁₂=ω₁/ω₂=1. If slider 4 is shifted (and clamped), then the average transmission ratio will remain the same, the transmission ratio i₁₂ being variable within a revolution.
$987$LG,4L$