Elevator hoisting mechanism

Claim 1

IN AN ELEVATOR SYSTEM IN WHICH THE ELEVATOR CAR AND ITS COUNTERWEIGHT ARE SUSPENDED BY ROPING PASSING OVER AN IDLER SHEAVE AT THE TOP OF THE HOISTWAY, HOISTING MECHANISM FOR THE CAR AND COUNTERWEIGHT COMPRISING, A HOISTING SHEAVE LOCATED AT THE BOTTOM OF THE HOISTWAY, A SECONDARY SHEAVE POSITIONED ABOVE THE HOISTING SHEAVE AND MOVABLE VERTICALLY RELATIVE THERETO, HOISTING ROPING EXTENDING FROM THE BOTTOM OF THE CAR AROUND THE HOISTING SHEAVE, THENCE AROUND THE SECONDARY SHEAVE, BACK AROUND THE HOISTING SHEAVE AND UP TO THE BOTTOM OF THE COUNTERWEIGHT, FLUID ACTUATED MECHANISM INCLUDING A SECONDARY SHEAVE SUPPORT SUPPORTING THE SECONDARY SHEAVE FOR EXERTING FORCE THEREON TO MOVE IT UPWARDLY WITH RESPECT TO THE HOISTING SHEAVE TO PROVIDE TRACTION BETWEEN THE HOISTING ROPING AND HOISTING SHEAVE, MEANS FOR SUPPLYING FLUID TO SAID FLUID ACTUATED MECHANISM AT A PRESSURE TO CAUSE SUFFICIENT TENSION IN THE HOUSING ROPING TO INSURE THE DESIRED AMOUNT OF SAID TRACTION, NOTWITHSTANDING STRETCHING OF THE ROPING, AND MEANS RESPONSIVE TO DOWNWARD FORCE EXERTED BY THE CAR ON THE SECONDARY SHEAVE SUPPORT TO ACTUATE THE FLUID ACTUATED MECHANISM TO REDUCE THE DISTANCE BETWEEN THE SECONDARY SHEAVE AND HOISTING SHEAVE TO RELEASE THE TRACTION.