Steerable mole for making a hole (31) in the ground (30), which drilling mole has a round tubular body (1), a guidable drilling instrument (2, 3) mounted in front on this body (1) by means of a ball and socket joint (4, 5) and means (7-9) mounted in the body (1) in order to guide the drilling instrument...http://www.google.com.au/patents/US5002138?utm_source=gb-gplus-sharePatent US5002138 - Steerable drilling mole
