Abstract: A free-swinging cutter element for a timber thinning machine includes a generally stirrup-shaped member having an outer wall and integral side walls. Each half of the member is formed as the frustrum of a triangle so that bevels on the upper and lower surfaces form sharp cutting edges that incline to respective upper and lower points in the center of the outer wall. This construction moves the center of mass further outward toward the outer wall to increase chipping and cutting efficiency, which is further increased by the form of the cutting edges. A single edged cutter having similar overall shape also is provided.

Abstract: A folding telescoped drill rig mast having wheel assemblies which travel along the power swivel guide rail to guide the telescoped upper mast as it retracts or extends within the lower mast. The fully extended upper mast locks into a transfer frame which moves laterally relative to the lower mast between a first position with the upper guide rail offset from the lower guide rail to a second position with the upper guide rail in longitudinal alignment with the lower guide rail. This lateral movement aligning the upper and lower masts enables pinning the upper and lower masts together to transfer the upper mast loading to the support members of the lower mast. The mast includes a base structure, a lower mast with a guide rail, and an upper mast held within the lower mast. The upper mast includes a guide rail for the power swivel.

Abstract: In accordance with an illustrative embodiment of the present invention, a cased borehole is drilled under surface obstructions in a single pass operation. The drilling apparatus includes a rotary drill bit mounted on a guide head having a ball joint connection to a housing. Remote controlled hydraulic cylinders enable steering of the guide head and bit, so that the hole direction can be controlled at will. Casing sections connected to the housing are added end-to-end as the borehole is lengthened, and axial thrust is applied to the casing string at the borehole entrance by a drilling rig to force the bit against the formations. The bit is driven by drill pipe that is centralized within the casing, so that when the bit, guide head and housing emerge from the ground, these elements can be disconnected, and the drill pipe pulled out of the casing to leave an unobstructed, lined borehole that is formed in a single pass.

Abstract: A cantilevered mast drilling rig is disclosed in which the erection operation for elevating the cantilevered mast and the drill rig floor to the elevated operating positions is a single step procedure. Both the cantilevered mast and the drill rig floor are completed on the ground prior to the elevating operation. The drill rig floor is pinned to the cantilevered mast so that, in response to actuation of the drawworks, the mast and drill rig floor are elevated to their operating positions as a single unit in a single operation.

Abstract: A system for erecting elevated floors where a first support floor with a drawworks thereon is connected to one end of a base structure by two pair of parallel spaced pivotable links and a second support floor is coupled to the opposite end of the base structure and by two pair of parallel spaced pivotable links. In accordance with the invention a strong back is erected about midway of the length of the base forming a rigid frame and supporting elevated sheaves at each side of the base structure. A pair of cables are adapted to pass over said sheaves, one on each side of said base structure and connect first to said first floor for erection and then to said second floor for erection.