Drill head for use with microtunneling apparatus

A drill head for use with a microtunneling apparatus to produce a bore including a housing having an annular shell and a radial member adjacent a distal end of the housing, a cutter bar having at least one cutting element positioned for front cutting, the cutter bar is rotatable across the radial member within a working zone of the bore to produce swarf, the housing including an annular body housing an articulated joint and a plurality of radially mounted actuators positioned about the articulated joint that are operable for adjusting an angle of articulation of the articulated joint;

• wherein the actuators are hydraulic rams (hereafter hydraulic articulation rams) each including a piston (hereafter articulation piston) which is arranged to move longitudinally relative to the annular body, each articulation piston having a part spherical surface adapted to interact with a socket so as to allow the articulation piston to move axially while permitting angular adjustment of the articulated joint,
• wherein the drill head further includes an input shaft at a proximal end of the annular body that is rotatable around a drive axis, an output shaft extending towards the distal end of the annular shell associated with the cutter bar so that the cutter bar rotates about an output axis, and an articulated joint within the housing between the input shaft and the output shaft that is adjustable so as to adjust an angle of articulation between the input shaft and the output shaft.