10 and a pin 12 the crankshaft is journalled for rotation in the main cylinder structure about the central axis of the main crankshaft segment 8 the crankshaft 6 is provided with a means such as a gear 14 for coupling power to a consuming device not shown the crankshaft segment 8 is hollow and accommodates a ramp housing 18 that is slidable axially within the crankshaft segment 8 but is restrained against rotation relative to the segment 8 the outer end of the crankshaft segment 8 the right end as seen in fig2 is provided with a sleeve bearing 22 the outer end of the ramp housing accommodates a ball thrust bearing 24 which is aligned with the slide bearing 22 a cylindrical operating shaft 28 is secured to the ball thrust bearing 24 by a bolt 26 and extends through the slide bearing 22 and is coupled to an adjustment mechanism not shown for displacing the operating shaft axially relative to the crankshaft segment 8 the adjustment mechanism may be for example hydraulic or electromechanical at its inner end the left end seen in fig2 the crankshaft segment 8 is attached to the crank web 10 and contains a lever support insert 30 the lever.