Matching Pairs Drilling RigOnline version Parts of drilling rig by Tatiana Yaikina 1 kelly 2 rotary drive 3 travelling block 4 mud pit 5 derrick 6 draw works 7 crown block A large structure standing on four legs and reaching the crown block. A steel frame on beams at the top of the derrick. A steel pipe, located at the top of drill string. A steel frame with wheels which moves up or down in the derrick A machine used to impart rotational power to the drill string. Steel tank used as a mud collector. A hoisting mechanism which raises or lowers the drill pipe and drill bit.