The invention relates to a device comprising a crankshaft (100) and least one conrod (200) having a big end (202) mounted on a crank pin (102) of the crankshaft (100). The crank pin (102) and the big end (201) of the conrod (200) comprise bearing surfaces (108, 202) which are in close contact to one another in a load-bearing area that bear the forces acting between the big end (201) of the conrod and crank pink (102) when the device is operated. According to the invention the bearing surface (108) of the crank pin (102) in its load-bearing area features a concavely curved profile in the longitudinal shaft section and the bearing surface of the big end (201) features a convex profile being in close contact with the concave profile of the crank pin (102).