Pipe wiper assembly for a well drilling unit
 A pipe wiper assembly is provided which comprises a first housing for supportingly receiving at least one resilient wiper member, and a second housing supported above the well bore for connecting the first housing to the stack assembly of the drilling unit. The first and second housings are interconnected such that the first housing is selectively movable in response to vertical deviations of the drill pipe as the drill pipe is withdrawn from the vertically extending well bore. 
E
E21B
inventional
Steven B. Ronald J.
Mason Mason