Abstract: In order to arrive at an eccentric mechanism which ensures that the eccentricity or the connecting rod stroke position is adjustable and after turning off the eccentric mechanism always is identical to the one before turning on the eccentric mechanism, the invention proposes that the cylinder shaped eccentric (16) of the eccentric shaft (10) is pivoted in the cylinder bore of an eccentric bush in a manner that ensures that when the eccentric mechanism is at a standstill concentricity is obtained when the eccentricities of the eccentric shaft and the cylinder bore of the eccentric bush cancel each other out while when the eccentric shaft (10) rotates due to the centrifugal force on at least one actuator (27) a counter-rotation of eccentric shaft and eccentric bush occurs automatically due to the centrifugal force while canceling the concentricity and the eccentricity becomes effective on the main drive pinion of the eccentric mechanism or vice versa.