A rod section of a ground drilling rod configured at its end to form at least one plug connection and having at one end (a) a connecting plug with an outer contour; or (b) a connecting socket with an inner contour, the outer contour or the inner contour being essentially sinusoidal in cross section.

The invention relates to a drill head of a ground drilling device having a drill bit and an attachment which can be fastened to the drill bit, wherein at least one dowel pin is provided for holding the attachment on the drill bit, and the drill bit has one or more receptacles for a dowel pin, wherein the receptacle is enlarged with respect to the radius of the dowel pin.

Provided is an inner string and a well system. The inner string, in one aspect, includes an inner tubular including a sidewall having a thickness (t.sub.3), the inner tubular having an orientation port extending entirely through the sidewall to provide fluid access from an interior of the inner tubular to an exterior of the inner tubular. The inner string, according to one aspect, further includes a weighted swivel located around the inner tubular, the weighted swivel including an orientation slot, the orientation slot configured to align with the orientation port to provide a pressure reading indicative of a relative location of the inner tubular to the weighted swivel.

A torque transfer system includes a drive shaft threaded into a housing. The drive shaft includes shaft splines. The housing includes housing splines. A sleeve includes inner splines and outer splines. The inner splines are configured to interlock with the shaft splines and the outer splines are configured to interlock with the housing splines.

A system includes an upper connection having a ring shape with an external surface, where upper splines are formed on the external surface and the upper connection is fixed to the upper section. The system also includes a lower connection having a ring shape with an internal surface, where lower splines are formed on the internal surface and the lower splines are configured to mate with the upper splines of the upper connection. Further, the system includes a fishing sub having a first lateral end and a second lateral end, where the first lateral end is fixed to the lower connection by shear pins configured to shear when a pre-determined tension is applied to the system, and the second lateral end is fixed to the lower section. The upper connection is inserted into the lower connection to form an engagement between the upper section and the lower section.

A system includes an upper connection having a ring shape with an external surface, where upper splines are formed on the external surface and the upper connection is fixed to the upper section. The system also includes a lower connection having a ring shape with an internal surface, where lower splines are formed on the internal surface and the lower splines are configured to mate with the upper splines of the upper connection. Further, the system includes a fishing sub having a first lateral end and a second lateral end, where the first lateral end is fixed to the lower connection by shear pins configured to shear when a pre-determined tension is applied to the system, and the second lateral end is fixed to the lower section. The upper connection is inserted into the lower connection to form an engagement between the upper section and the lower section.

A retention system for attaching a collar to a pipe. The collar has an internally-disposed groove configured for placement of a ring. The ring is sized such that in one orientation, it can enter the collar between torque-transmitting features into the internally-disposed groove. Once in the groove, the ring may be adjusted such that its aperture is generally aligned with the axis of the collar. In this orientation, the features retain the ring within the groove. A bolt and a pipe may then be placed within the collar from opposite sides. The bolt is attached to the pipe through the ring. Once joined, the collar is joined to the pipe, forming its box end. Such a retention system may be used to join a series of inner pipe members of a dual-member pipe assembly, as in horizontal directional drilling.

A retention system for attaching a collar to a pipe. The collar has an internally-disposed groove configured for placement of a ring. The ring is sized such that in one orientation, it can enter the collar between torque-transmitting features into the internally-disposed groove. Once in the groove, the ring may be adjusted such that its aperture is generally aligned with the axis of the collar. In this orientation, the features retain the ring within the groove. A bolt and a pipe may then be placed within the collar from opposite sides. The bolt is attached to the pipe through the ring. Once joined, the collar is joined to the pipe, forming its box end. Such a retention system may be used to join a series of inner pipe members of a dual-member pipe assembly, as in horizontal directional drilling.

A modular foundation support system includes modular foundation support components including self-aligning and torque transmitting coupler features wherein a plurality of axially elongated ribs are aligned with a plurality of axially elongated ribs to rotationally interlocke the modular foundation support components to one another.

A modular foundation support system includes modular foundation support components including self-aligning and torque transmitting coupler features wherein a plurality of axially elongated ribs are aligned with a plurality of axially elongated ribs to rotationally interlocke the modular foundation support components to one another.