| 摘要 |
The present invention is a cable drawworks for a drilling rig having a three - phase AC electric motor controlled by a variable frequency drive control system. A primary drive transmission consisting of a chain and sprockets 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 o n 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 consists of a planetary gear transmission set where the ring gear is fixed to the drawwork s frame, the planetary gear sub-assembly is attached to the cable drum and the sun ge ar is affixed to the drum shaft. Each end of the cable drum has a brake drum and a brake band wrapped around thereon. A brake actuating system is used to tighten the bands around each drum during braking conditions and includes an equalization linkage system between the brake bands resulting in equal braking forces being appli ed to each brake drum. The present invention results in a simplified cable drawwor ks system that is compact enough to be mounted on the drilling rig floor and th at eliminates the need for liquid cooling of the braking mechanism.
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