Crane

Claim 1

IN COMBINATION, A CRANE CARRIER COMPRISING A MOBILE CHASSIS FRAME HAVING STEERABLE GROUND-ENGAGING WHEELS SUPPORTING THE SAME, A TURNTABLE MOUNTED ON SAID FRAME, BOOM HOISTING MECHANISM ON SAID TURNTABLE, A MAIN BOOM PIVOTED TO SAID TURNTABLE, MEANS TO HOLD SAID MAIN BOOM IN A VERTICAL POSITION ON SAID TURNTABLE, A BOOM FOOT STRUCTURE MOUNTED ON THE TOP OF SAID MAIN BOOM PROVIDING A BOOM PIVOT LATERALLY OFFSET FROM SAID MAIN BOOM AND FIXED WITH RESPECT THERETO, A SECONDARY BOOM PIVOTED TO SAID OFFSET BOOM FOOT PIVOT, A FIRST MAST STRUCTURE PIVOTED TO SAID BOOM FOOT STRUCTURE REARWARDLY OF SAID SECONDARY BOOM PIVOT, PENDANTS INTERCONNECTING THE PEAK OF SAID FIRST MAST STRUCTURE AND THE PEAK OF SAID SECONDARY BOOM, A SECOND MAST STRUCTURE PIVOTED TO SAID BOOM FOOT STRUCTURE, PENDANTS INTERCONNECTING SAID FIRST AND SECOND MAST STRUCTURES, AND BOOM DERRICKING CABLE MEANS INTERCONNECTING THE PEAK OF SAID SECOND MAST STRUCTURE AND SAID BOOM HOISTING MEANS OPERATIVE TO PIVOT SAID SECONDARY BOOM ABOUT SAID OFFSET BOOM PIVOT ON THE BOOM FOOT STRUCTURE AT THE TOP OF SAID MAIN BOOM, THE ANGLE OF INCIDENCE BETWEEN SAID SECONDARY BOOM AND THE BOOM PENDANTS INTERCONNECTING THE PEAK OF SAID SECONDARY BOOM AND THE FIRST MAST STRUCTURE INCREASING AS THE ANGLE BETWEEN SAID MAIN AND SECONDARY BOOMS INCREASES, THE MOMENT ACTING ON SAID SECONDARY BOOM AT THE MAXIMUM POSITION OF ELEVATION BEING SUBSTANTIALLY EQUAL TO THE LENGTH OF SAID FIRST MAST STRUCTURE AND THE DISTANCE BETWEEN SAID OFFSET BOOM PIVOT AND THE PIVOTAL CONNECTION OF SAID FIRST MAST STRUCTURE WITH SAID BOOM FOOT STRUCTURE.