Patent ID: 6499611
Filing Date: 2002-12-31
Classification: B66C

Abstract:
A mobile harbor crane for normal and heavy load operation, comprising:an undercarriage with a superstructure rotatably mounted thereon; a tower arranged on said superstructure and a jib pivotally connected to a front side of said tower for pivoting about a substantially horizontal axis; a luffing cylinder coupled between said jib and said tower for holding and pivoting said jib during a normal operating mode; a normal load lifting mechanism comprising a normal load hoisting cable with a normal load snatch block suspended therefrom for picking up a load during said normal operating mode; a heavy load lifting winch arranged on said superstructure and comprising a heavy load lifting cable; a deflecting roller and a heavy load snatch block having a roller assembly arranged on said jib so that said heavy load lifting cable is guidable over said deflecting roller and to said roller assembly of said heavy load snatch block for lifting loads during a heavy load operating mode, wherein said normal load hoisting cables are detachable from said normal load snatch block and fixable to a head of said jib such that said normal load lifting mechanism is arrangeable as a luffing mechanism for said jib during said heavy load operating mode, said luffing cylinder being unloaded during said heavy operating mode and serving as a fall-back support for said jib; and means for increasing a righting moment of said mobile harbor crane during said heavy load operating mode, wherein said means for increasing a righting moment comprises a counter jib pivotally coupled to a rear side of said tower opposing said front side on which said jib is pivotally connected, a pivoting cylinder operatively arranged between said tower and said counter jib for pivoting said counter jib in a vertical jib pivoting plane, said pivoting cylinder further comprising a fall-back support for said counter jib, a bracing means having one end fixed to said head of said jib and another end at a foot end of said tower, said bracing means being further connected to said counter jib for changing an inclination of said counter jib via a change in a length of said bracing means, and a supporting device comprising a heavy load counterweight suspended from said counter jib and arranged in vicinity of the ground, wherein a range of swing of said supporting device is settable via a change in inclination of said counter jib.