Apparatus for excavating a trench under a pipeline on the bottom of the sea

摘要

An apparatus for digging a trench under a pipeline or cable which has been placed on the sea bottom. A carriage moves along the pipeline. Two forward digging chains are mounted on the carriage so as to be disposed on each side of the pipeline, and so that their ends define two points on a line extending beneath the pipeline or cable. The digging chains are arranged one behind the other in the direction of movement of the carriage. Each digging chain is movable from a first position of incline with respect to the direction of movement of the carriage to a second position substantially at right angles thereto. The digging chains are shaped and positioned so as to dig the trench with an undercut slope at both sides.