US Patent 7651170 Bore head for microbore operation

Boring apparatus for drilling laser guided microbore tunnels uses a liquid stream to remove soil as slurry and an airstream to conduct the slurry away from the bore head. The cylindrical head houses a drill shaft steered by a pair of remotely controlled rams according to the position of a laser spot on a target fixed close to the end of the drill shaft. Small arcuate steering movements shift the cutter up and down through a first ram alongside the shaft working through a linkage. Side to side steering is provided by a second ram acting directly on the shaft. The components are mounted on an axial base wall which gives repair access and camera view of the target. A drilling platform has rams for advancing the cylindrical head.