Counterbalancing type crane

A counterbalancing type crane, comprising:

• a crane body which comprises a travelling unit and a swing unit,
• a tiltable boom mounted on said crane body for hanging a load through a hoisting line;
• a tiltable mast mounted on said crane body;
• a boom guy line disposed between an upper portion of said mast and an upper portion of said boom, said boom guy line being changeable in length;
• a mast guy line attached at an upper end thereof to the upper portion of said mast;
• a gantry disposed at a rear portion of said swing unit and having a mounting portion located an an upper portion thereof;
• and
• a counterweight car with a counterweight placed thereon;
• connecting arm means for vertically pivotably and removably connecting said counterweight car to the rear portion of said swing unit;
• a strut connected between an upper portion of said counterweight car and an upper portion of said gantry;
• a guy rope connected between the upper portion of said counterweight car and said swing unit below the gantry, wherein a lower end of said mast guy line is attached to said counterweight car so as to be detachable therefrom and attachable to said mounting portion of said gantry.