A parallelogram linkage scales the motion of input point P at output point Q. Here P is driven along a circle. Changing the scale factor changes both the output circle size and output speed by that same factor.
At 1×, 15 cycles/min takes 4 seconds per cycle. Playback scale changes elapsed time only, not the motion relationship. Drawing scale stays fixed during playback.
Change blue values → use the button to return to the drawing
L: 2–10,000 mm; r: 0.1 mm to 0.6L; scale: 1.1–4×; rate: 0.1–3,000 cycles/min.Compare the small circle traced by blue P with the larger circle traced by red Q. O, P and Q remain collinear.
The linkage enforces Q = kP about fixed O, with OA = AP = L, OB = kL, BC = AP, PC = AB and BQ = k·BC. P traces a circle of radius r centred at (1.15L, 0.55L). The input path is prescribed; this is not a single-motor drive model. Joints are ideal pins and links rigid. Backlash, deflection and collisions are not calculated; crossing rods represent separate layers.
