دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: a pin fitting into a hole in an abutting piece to prevent motion or slipping.

n: a kelly bushing that has four steel dowels. or pins. that fit into corresponding holes in the master bushing. When the pins are engaged with the holes. the rotating master bushing also turns the kelly bushing. which then turns the kelly and the drill stem. See kelly, kelly bushing, master bushing.

n: a master bushing that has four holes symmetrically positioned on its outside perimeter and into which fit four corresponding steel dowels. or pins. on the kelly bushing. When the pins are engaged into the holes and the master bushing turns. the kelly bushing also turns. See kelly bushing, master bushing.