| 摘要 |
A framework type mast structure is pivotally mounted on a base structure. A self-supporting pedestal structure including a gin pole structure which is pivotally mounted on the base structure adjacent the mast structure. The pedestal structure with the gin pole is tilted to vertical position, and the gin pole secured. Sheaves carried by the gin pole cooperate with a sling line which runs to and is looped over the hook of the traveling block of the drilling rig for purposes of raising the mast structure to an upright position. A second self-supporting pedestal structure is tilted into position on the base structure on the other side of the mast structure and below a racking board assembly carried by the mast structure which is used to support the lower end of racked drill pipe independently of the mast structure. A rotary table is supported independently of the mast structure by means of a horizontal support structure which extends through the framework of the mast structure and is supported by the two pedestal structures. A working floor is carried by the gin pole pedestal structure which, together with the rotary table and the pipe supporting floor of the second pedestal structure, is positioned at an elevated location above the base structure. In a second embodiment, a separate gin pole structure is not used and the mast raising sheaves are instead mounted on the main body of the first pedestal structure.
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