Patent ID: 7575222

Claim:
A drawworks for a drilling rig comprising, a main frame, a cable drum affixed to a drum shaft, said drum shaft being rotatably supported respective said main frame, First and second drum brake assemblies having brake drums affixed to and spaced apart by said cable drum and axially aligned respective one another, a prime mover, a drive train, a clutch device interconnecting said prime mover respective said cable drum shaft, each said brake assembly includes a brake band having ends, one said brake band circumferentially extending about one said brake drum, one end of said brake band being affixed to the main frame with the remaining end thereof connected to a brake equalizer apparatus that equalizes the braking forces applied to each said brake assembly; said brake equalizer includes apparatus for moving the brake bands relative the brake drums; and further including a plurality of low friction alignment rollers radially extending toward said drum shaft to engage and position the brake bands closely adjacent the brake drums and thereby arrange said brake bands into concentric alignment respective the brake drums; and linkage including bell-cranks for applying equally divided force between each said brake band and brake drum therefore.