Underground, fluid driven directional drilling device

Abstract From the Canadian patent

An articulated non-rotating drill string has an articulated head which incorporates a first stage impeller and a second stage impeller connected together by a universal joint to allow articulation along with a, piston arrangement covered by a shroud associated with one of the articulating elements, the pistons being adapted to push differentially against the shroud and articulate the drilling head. Individual elongate sections of the drill string are also articulated together in a non-rotating and fluid-tight manner using, partial spherical cavities and complementary inserts. Compression springs adjacent each articulating joint are arranged so as to urge the articulated portions into …