Patent ID: 8141725
Filing Date: 2012-03-27
Classification: B66C

Abstract:
1. A jib crane comprising: a jib pivoted to a revolving table for derricking motion; a hoisting device having a hoisting drum on said revolving table with hoisting wire ropes being wound around the hoisting drum, a hanger being suspended by the hoisting wire ropes unreeled from the hoisting drum via a tip of the jib while tips of the hoisting wire ropes are fixed to said revolving table, said hanger being lifted and lowered by reeling and unreeling said hoisting wire ropes to and from said hoisting drum; and a derricking device having a derricking drum on said revolving table with derricking wire ropes being wound around the derricking drum, said jib being suspended by the derricking wire ropes unreeled from the derricking drum while tips of said derricking wire ropes are fixed to said revolving table, said jib being derricked by lead-in and pull-out of said derricking wire ropes to and from said derricking drum, wherein: the jib crane comprises a conversion device on said revolving table for converting load applied to said hoisting wire ropes into lead-in of said derricking wire ropes during a burden handling work, and said conversion device comprises: