Patent ID: 7210670

Claim:
A drawworks apparatus for raising and lowering items down a well bore, said drawworks comprising: a frame having a working area within inner surfaces thereof where the raising and lowering of items occurs; a main drum spool having at least a portion situated within said working area for raising and lowering items down the well bore via a length of cable wound thereon, said main drum spool extending through and rotatably mounted directly to said frame by a first set of bearings; a main drum shaft rotatably and concentrically supported by said main drum spool in a manner in which said main drum shaft is isolated from wireline pull from said main drum spool imposed on said main drum spool during operation of said drawworks; an auxiliary drum spool for raising and lowering items down a well bore via a length of cable wound thereon, said auxiliary drum spool rotatably supported by said frame by a second set of bearings; an auxiliary drum shaft rotatably and concentrically supported by said auxiliary drum spool in a manner in which said auxiliary drum shaft is isolated from wireline pull from said auxiliary drum spool imposed on said auxiliary drum spool during operation of said drawworks; a drive mechanism located outside of said working area for rotating said main drum spool and said auxiliary drum spool, said drive mechanism providing a driving force input through said auxiliary drum shaft via an input chain drive, said main drum spool having a clutch for engaging said drive mechanism located outside the working area and externally separated from said input chain drive; and a first brake assembly located outside of said working area, said first brake assembly being connected to said main drum spool so as to reduce the rate of rotation of said main drum spool during operation of said drawworks.