Telescoping boom for material handling mechanism

Claim 1

IN A MATERIAL HANDLING DEVICE, IN COMBINATION, A VERTICALLY DISPOSED MAST; A BOOM MOUNTED ON SAID MAST AND COMPRISED OF A HOLLOW OUTER SECTION CONNECTED TO THE MAST AND A PLURALITY OF TELESCOPING INNER SECTIONS DISPOSED WITHIN THE SAID OUTER SECTION FOR RECIPROCAL ADVANCEMENT THROUGH THE FORWARD END OF THE OUTER SECTION AND RETRACTION WITHIN SAID OUTER SECTION; MEANS ON EACH SAID SECTIONS PROVIDING SUPPORT FOR THE SECTION TELESCOPINGLY RECEIVED THEREIN; MEANS MOUNTED ON SAID OUTER BOOM SECTION AND CONNECTED WITH SAID TELESCOPING SECTIONS FOR SELECTIVELY ADVANCING SAID TELESCOPING SECTIONS RELATIVE TO ONE END OF SAID OUTER SECTION; A SHEAVE BLOCK CONTAINING A PLURALITY OF SHEAVES MOUNTED UPON THE OUTER SECTION ADJACENT THE FORWARD END THEREOF; A SECOND SHEAVE BLOCK CONTAINING A PLURALITY OF SHEAVES DISPOSED IN REARWARD SPACED RELATION TO SAID FIRST NAMED SHEAVE BLOCK AND CONNECTED TO A POWER MEANS FOR ADVANCING AND RETRACTING SAID SECOND NAMED SHEAVE BLOCK RELATIVE TO THE FIRST NAMED SHEAVE BLOCK; A SHEAVE MOUNTED ADJACENT ALTERNATE FORWARD AND REAR ENDS OF SUCCESSIVE TELESCOPING BOOM SECTIONS WITHIN SAID OUTER SECTION, WITH ONE SUCH TELESCOPING SECTION HAVING A SHEAVE MOUNTED ADJACENT EACH END THEREOF; A CABLE REEVED OVER THE SHEAVES OF THE TELESCOPING MEMBERS TO THE SHEAVE BLOCK ATTACHED TO SAID POWER MEANS, THENCE TO SAID SHEAVE BLOCK MOUNTED UPON SAID OUTER SECTION WITH ONE END OF THE CABLE FROM SAID SHEAVE BLOCKS BEING ANCHORED TO SAID OUTER SECTION AND THE OPPOSITE END OF THE CABLE DEPENDING OVER A SHEAVE ON THE OUTER END OF THE INNERMOST TELESCOPING SECTION AND TERMINATING IN A LOAD LIFTING HOOK.