The present invention relates to a heat engine having shafts with gears, position gears and a plurality of actuators. Energy is harnessed from the first shaft as it rotates. The second shaft can be coupled to the first shaft to transfer energy from the second shaft to the first shaft. One coupler is a chain. Position gears orient the chain wherein the rotation of the second shaft is inverted upon the first shaft so that the first shaft has a constant rotational orientation. Each actuator is preferably a double acting actuator that can supply force to both push and pull upon a belt connected to the actuator rod. A 1-way clutch and gear connects the belt to each shaft wherein the belt (driven by actuator) imparts a positive force upon the first shaft on the out stroke and a positive force upon the second shaft on the return stroke.