Abstract: A combination crane A is formed by connecting two crawler cranes 1L and 1R. Each crawler crane is provided with at least a lower propelling body 3 which can be propelled by crawlers 2, an upper revolving body 5 rotatably mounted on the lower propelling body 3 by a swing unit 4 provided between them, a boom 6 whose base section is tiltably supported on the upper revolving body, a tilting mechanism 10 that raises and lowers the boom and a hoist mechanism that hoists and lowers the lifting members 12 hung by a hoist rope 11 from the top of the boom. Both upper swing bodies of two cranes are connected together with a connecting beam 20. Swing motion is performed by driving the one crawler crane to move around the other crawler crane which is free to rotate and is locked against propulsion.

Abstract: A combination crane A is formed by connecting two crawler cranes 1L and 1R. Each crawler crane is provided with at least a lower propelling body 3 which can propel by crawlers 2, an upper revolving body 5 rotatably mounted on the lower propelling body 3 by a swing unit 4 provided between them, a boom 6 of which base section is tiltably supported on the upper revolving body, a tilting mechanism 10 that raises and lowers the boom and a hoist mechanism that hoists and lowers the lifting members 12 hung by a hoist rope 11 from the top of the boom. Both upper swing bodies of two cranes are connected together with a connecting beam 20. Swing motion is performed by driving the one crawler crane to propel around the other crawler crane which is free to rotate and is locked to propel. The combination crane can change the direction of the body, and can increase the lifting capacity twice as much without troubles, and can be embodied easily.