Patent ID: 8839760

Claim:
An apparatus for rotating a crankshaft, the crankshaft including a main shaft and an axially offset crank pin, each end of the crank pin being connected to the main shaft by a respective crank arm, the apparatus comprising: a first piston; a connecting frame attached to the first piston, wherein the first piston is configured to drive the connecting frame in reciprocating motion; a hub rotatably mounted within the connecting frame, the hub having defined therein a channel, the crank pin being disposed within the channel; and a locking mechanism having a locked state in which the hub is prevented by the locking mechanism from rotating within the connecting frame and an unlocked state in which the hub freely rotates within the connecting frame, wherein the reciprocating motion of the first piston and the connecting frame impart reciprocating travel of the crank pin between a first end of the channel to a second end of the channel and consequent rotation of the main shaft when the locking mechanism is in the locked state, wherein the crankshaft and the hub rotate freely when the locking mechanism is in the unlocked state, and wherein the first piston and the connecting frame are in a stationary position when the locking mechanism is in the unlocked state.