Green clutch (on the left) linearly reciprocates (its motion source is not shown). It makes the blue clutch move in opposite direction thanks to the cable drive.
Both clutches make grey wire move to the left when they move to the left. Thus the wire move continuously to the left.
So this mechanism converts reciprocating linear motion into continuous oneway one.
If the wire is the belt of a belt drive of two pulleys: linear reciprocating motion is converted into continuous oneway rotation of the pulleys.