DOUBLE CRANK TYPE INTERNAL COMBUSTION ENGINE

PURPOSE:To reduce vibration so as to improve mechanical efficiency by connecting each piston side end of connecting rods rotatably with each other, and providing thereby a displacement absorbing means which connects said end so as to be freely displaced to a specified direction. CONSTITUTION:Both a set of connecting rods 30A and 30B and a set of crank shafts 20A and 20B are arranged to one piston 13, and these crank shafts 20A and 20B are thereby allowed to be rotated synchronously in parallel with but opposite to each other. Large end sections 31A and 31B of the connecting rods 30A and 30B are rotatably connected with crank pins 22A and 22B. Small end sections 32A and 32B are connected with the piston 13 via an eccentric pin 40 acting as a displacement absorbing means. This constitution thereby not only enables vibration to be significantly reduced but also enables mechanical efficiency to be improved.