Two parallelogram mechanisms are connected together by a gear drive of -1 transmission ratio.
Lengths of orange, green and violet cranks are equal.
At starting position all cranks are horizontal.
Input: orange crank.
Blue and pink conrods have circular translating motions. Their horizontal displacements are equal.
A piston is fixed to the blue conrod.
A cylinder is fixed to the pink conrod.
Stroke length of relative motion between the piston and cylinder is 4 times of the crank lengths.
The piston does not apply lateral force to the cylinder.
The yellow and grey conrods mounted on eccentrics of the cranks help the parallelogram mechanisms to overcome dead positions.