Patent attributes
A cable drawworks for a drilling rig has an electric motor and a primary drive transmission which connects the motor to a drum shaft that passes through the hub of a cable drum. The drum shaft is rotatably mounted on the drawworks frame whereas the cable drum is rotatably mounted on the drum shaft. The drum shaft connects to a secondary drive transmission that connects the drum shaft to the cable drum. The secondary drive transmission has a planetary gear transmission set. Each end of the cable drum has a brake drum and a brake band wrapped around thereon. A brake actuating system is used to selectively tighten the bands and includes an equalization linkage system resulting in equal braking forces being applied to each brake drum. The simplified cable drawworks system is compact enough to be mounted on the drilling rig floor and eliminates the need for liquid cooling of the braking mechanism.
