bicycle power crank system

I've had a design in my head for a while for a bicycle cranking system that would maximize the time spent pushing down on the cranks. The left and right cranks can move somewhat independently of each other--each driving its own cam-shaped chain ring and chain. This allow the cranks to have a slower speed when moving down but a higher speed when coming up.

Top view. From top down: left crank, bottom bracket, adapter, red chain ring, blue chain ring, right crank.

The left crank is a normal crank that is attached to the standard bottom bracket. On the right side of the bottom bracket is an adapter that drives the red chain ring. Between the adapter and the right crank are bearings that allow them to spin freely of each other.

The blue chain ring is in the middle of the more powerful down stroke.

The red chain ring has to move faster during the up stroke and is now seen starting the down stroke.

The system is synced by the chains connected to two identical sprockets on the rear wheel hub. Two separate spring-loaded chain tensioners will be used to take up slack on each chain. The tensioners would probably have to tension the chain fairly tightly to allow the motion of the rear wheel to drive the cranks back up.

Side view of the blue chain ring power stroke and the red chain ring faster up stroke.

Side view of the blue chain ring finishing power stroke while the red chain ring is just starting its power stroke.

Chain rings are designed with three mounting positions to allow tuning of when the power stroke begins. More or finer positioning could be added. Different cam shaped chain rings could also be designed to accommodate the preference of different riders.