This invention relates to mobile earth drilling units, and particularly to an apparatus for storing and handling lengths of drill pipe to be connected in a drill string for drilling operations.
A type of drilling unit known as a blast hole drill is used in surface mining and quarrying operations. The unit is typically mobile, being mounted on a vehicle that travels on tractor crawlers. A long, pivoting mast is carried horizontally when the unit is on the move, and is set upright or at a slight angle from upright (i.e. within 30.degree. of vertical) for drilling.
Lengths of drill pipe are typically stored within the mast. The drill pipes are each stored in pipe handling mechanisms which can move a drill pipe from a storage position to a position where it can be added to the drill string. Examples of the mast storage of drill pipes are found in U.S. Pat. Nos. 3,212,593 to Reischel issued Oct. 19, 1965, 3,860,126 to Neimark, et al. issued Jan. 14, 1975, and 4,595,066 to Neimark, et al. issued Jun. 17, 1986. It has also been proposed to mount a carousel along the length of the mast, with the carousel holding multiple drill pipes. The carousel is rotatable and movable into a position where a drill pipe can be added or removed from the drill string. An example of this approach is shown in U.S. Pat. No. 3,985,189 to Jahnke, et al. issued Oct. 12, 1976.
In a well drilling unit, it has been proposed to store drill pipe segments and drill casing segments horizontally in a rack on the side of the drill unit. The drill pipes and casings are fed by gravity to a position in which they can be gripped by an arm to be raised to a vertical position for adding to the drill strings. An example of this approach is shown in U.S. Pat. No. 3,734,208 to Otto issued May 22, 1973.