Patent ID: 7055625

Claim:
An autonomous subsurface drilling device for drilling in a borehole comprising: (a) a pair of spaced-apart forward and rearward feet sections coupled by an axial thruster mechanism between them that can expand and contract along a main axis of the device to allow the feet sections to grip the borehole wall and alternately move the forward feet section forward and pull up the rearward feet section using an inchworm method of mobility; (b) at least a front drill section having a drill head for cutting into the borehole and conveying cuttings along the main axis of the device to an on-board depository for collecting the cuttings, so that cuttings do not have to be passed to the surface while the device is in operation deep below the surface, wherein said feet sections of the device each employs a scroll drive unit which spins about the axis of the device in order to extend and provide radial thrust to the feet for gripping the borehole wall.