Abstract: In a drilling apparatus of the type comprising a rotatable drilling shaft and a housing for rotatably supporting a length of the drilling shaft for rotation therein, a rotation restraining device associated with the housing for restraining rotation of the housing. In one embodiment, the rotation restraining device is comprised of at least one roller on the housing, the roller having an axis of rotation substantially perpendicular to a longitudinal axis of the housing and being oriented such that it is capable of rolling about its axis of rotation in response to a force exerted on the roller substantially in the direction of the longitudinal axis of the housing. In a further embodiment, the rotation restraining device is comprised of at least one piston on the housing.

Abstract: A variable gauge drilling apparatus and a method for assembling a variable gauge drilling apparatus for insertion in a subject borehole. The variable gauge drilling apparatus includes: an apparatus housing having a housing size which is suitable for insertion in a subject borehole which has a subject borehole size within a design range of borehole sizes; a plurality of interchangeable borehole engaging devices having different device sizes for mounting on the apparatus housing to provide the drilling apparatus with a drilling apparatus size within a range of drilling apparatus sizes, wherein the range of drilling apparatus sizes is compatible for use of the drilling apparatus within the design range of borehole sizes; and a universal borehole engaging device mount located on the apparatus housing, wherein the mount is configured to accept for mounting any one of the plurality of interchangeable borehole engaging devices.

Abstract: In a drilling apparatus of the type comprising a rotatable drilling shaft and a housing for rotatably supporting a length of the drilling shaft for rotation therein, a rotation restraining device associated with the housing for restraining rotation of the housing. In one embodiment, the rotation restraining device is comprised of at least one roller on the housing, the roller having an axis of rotation substantially perpendicular to a longitudinal axis of the housing and being oriented such that it is capable of rolling about its axis of rotation in response to a force exerted on the roller substantially in the direction of the longitudinal axis of the housing. In a further embodiment, the rotation restraining device is comprised of at least one piston on the housing.

Abstract: A method for orienting a rotary drilling system comprised of a rotatable drilling string, a drilling string communication system and a drilling direction control device, the drilling direction control device comprising a deflectable drilling shaft connected with the drilling string. The method for orienting the rotary drilling system may involve the steps of orienting the drilling string at a desired orientation and sensing the desired orientation of the drilling string with the drilling string communication system. Further, the method involves the steps of communicating a desired orientation of the drilling string to a drilling direction control device and then actuating the drilling direction control device to deflect the drilling shaft to reflect the desired orientation of the drilling shaft. The desired orientation of the drilling shaft may be communicated directly to the drilling direction control device or to the drilling direction control device through a drilling string communication system.

Abstract: A drilling direction control device, improvements in drilling direction control devices, methods for orienting a rotary driling system, and methods for rotary drilling. The drilling direction control device includes a rotatable drilling shaft, a housing for rotatably supporting a length of the drilling shaft, and a deflection assembly contained within the housing for bending the drilling shaft between a first support location and a second support location. The deflection assembly includes an outer ring which is rotatably supported on a circular inner peripheral surface of the housing and which has a circular inner peripheral surface that is eccentric with respect to the housing. The deflection assembly also includes an inner ring which is rotatably supported on the circular inner peripheral surface of the outer ring and which has a circular inner peripheral surface which engages the drilling shaft and which is eccentric with respect to the circular inner peripheral surface of the outer ring.