Double center luffing crane

A load lifting apparatus for raising a load at a site and moving said load in a substantially horizontal direction to a remote site where said load is lowered and desposited, said load lifting apparatus comprising:

• a base support member;
• a pivotal connector carried by said base support member;
• two substantially vertically extending masts each having an upper portion and a lower portion;
• said lower portion of each of said masts being pivotally supported on said pivotal connector for being pivoted penetratingly through a vertically extending plane extending upward from said pivotal connector;
• a substantially horizontally extending boom having a load-carrying end and a rear end;
• means for suspending said boom on an upper portion of each of said masts for pendulous movement;
• a draw works carried by said base support member;
• a load line means extending about said load-carrying end of said boom, said upper portion of each of said masts, and to said draw works for raising and lowering said load;
• means for selectively pivoting each of said masts about said pivotal connector through said vertical plane, causing said boom to be shifted in a pendulous movement relative to said masts for moving said load-carrying end of said boom substantially horizontally after lifting said load off said site and
• control radius means having an effective length dependent on the position of said boom relative to said mast connected between said rear end of said boom and said base support member for allowing constrained pivoting of said rear end of said boom with respect to said base support member.

A load lifting apparatus for raising a load at a site and moving said load in a substantially horizontal direction to a remote site where said load is lowered and deposited, said load lifting apparatus comprising:

• a base support member;
• two pivotal connectors carried by said base support member;
• two substantially vertically extending masts each having an upper portion and a lower portion;
• said lower portions of said masts being pivotally supported on said pivotal connectors for being pivoted penetratingly through a vertically extending plane extending upward from said pivotal connectors;
• two substantially horizontally extending booms each having a load-carrying end and a rear end;
• means for suspending said booms on an upper portion of each of said masts;
• a draw works carried by said base support member;
• a load line means extending about each of said load carrying end of each said boom, said upper portions of each said mast, and to said draw works for raising and lowering said load;
• means for selectively pivoting said masts about said pivotal connectors through said vertical plane, causing said booms to be shifted relative to said masts for moving said load substantially horizontally after being lifted off said site and
• control radius means having an effective length dependent on the position of said boom relative to said mast connected between said rear end of said boom and said base support member for allowing constrained pivoting of said rear end of said boom with respect to said base support member.

A load lifting apparatus for raising a load at a site and moving said load in a substantially horizontal direction to a remote site where said load is lowered and deposited, said load lifting apparatus comprising:

• a base support member;
• a pivotal connector carried by said base support member;
• a substantially vertical extending mast having an upper end and a lower portion;
• said lower portion of said mast being pivotally connected on said pivotal connection for being pivoted penetratingly through a vertically extending plane extending upwardly from said pivotal connector;
• a substantially horizontally extending boom having a load carrying end and a rear end;
• means for suspending said boom on an upper portion of said mast for pendulous movement;
• a draw works carried by said base support member;
• a load line means extending about said load carrying end of said boom, said upper portion of said mast, and to said draw works for raising and lowering said load;
• means for selectively pivoting said mast about said pivotal connector through said vertically extending plane causing said boom to be shifted in a pendulous movement relative to said mast for moving said load carrying end of said boom substantially horizontally after lifting said load off said site;
• means causing said load carrying end of said boom to rise as said load carrying end of said boom moves rearwardly, penetrating said vertically extending plane, said rising of said load carrying end of said boom working to raise the load being carried thereon, thereby retarding further rearward movement of said boom and said mast.