[GeeTwo]

I definitely like how the launcher can be held fully cocked with little torque required from the motor; probably little enough to let the gearbox hold it (especially if that last 12:1 reduction is through a worm gear).

Is the driven axle assumed to be located midway between the "pivot" and the "pin" mounted to the disc? Have different axle locations been investigated?

If the axle was not in the line between the pivot and the pin (below this line when horizontal), it appears that the two drive periods would overlap and merge into a single steadier pull, at the cost of introducing a null sector at the opposite part of the cycle.