Abstract: A drilling machine includes a frame, a tower that is supported by the frame, two tracks for movement over the ground, at least three yokes that interconnect the frame and the two tracks, at least three hydraulic cylinders, an inclinometer that senses the inclination of the frame and produces an output signal that is indicative of the inclination of the frame, and a controller that receives the output signal from the inclinometer. The tower includes a drill string. Each yoke is connected to the frame and one of the tracks. Each hydraulic cylinder is extendible and retractable in response to an associated control signal and connected to the frame and an associated yoke. The controller generates control signals for the hydraulic cylinders such that the hydraulic cylinders are controlled to extend or retract to maintain the frame in a level position.

Abstract: A drilling machine includes a frame, a tower that is supported by the frame, two tracks for movement over the ground, at least four yokes that interconnect the frame and the two tracks, a plurality of hydraulic cylinders, a plurality of sensors, and a controller. The tower includes a drill string. Each yoke is connected to the frame and one of the tracks. Each hydraulic cylinder is movable in response to a control signal and connected to the frame and a yoke. Each sensor senses a parameter indicative of force and generates an output signal that represents the force. The controller receives the output signals from the sensors, determines a center of gravity of the drilling machine, and generates the control signals for the hydraulic cylinders based on the center of gravity. Each hydraulic cylinder is controlled to move to maintain the center of gravity within a boundary area.

Abstract: A telescoping sub (50) for mining operations and the like. The telescoping sub (50) includes a rotor (94) portion coupleadle to the rotary head of a drilling rig, and a stator (74) portion that is coupleable to a drill rod. The rotor (94) portion is slideadly coupled to the stator (74) portion and is moveable with respect thereto between an extended position and a retracted position. With the telescoping sub (50) in the retracted position, the drilling rig is operated to drill to a first depth. The drilling rig is then operated to move the rotor (94) portion to the extended position, and the drilling rig is operated to drill to a second depth that is greater than the first depth.

Abstract: A drilling machine includes a frame, two tracks, and a plurality of yokes interconnecting the frame and the tracks. Each yoke is pivotable with respect to the frame by the extension and retraction of a hydraulic cylinder. Each of a plurality of sensors senses a parameter indicative of force and generates a signal representing the force. A controller receives the force signals, and generates control signals to extend or retract the hydraulic cylinders when an associated force deviation for a hydraulic cylinder exceeds a predetermined magnitude.