Apparatus for the subaqueous entrenching of pipes

Apparatus for the subaqueous entrenching of pipes, of the type generally comprising a framework, which can be positioned across the pipe to be entrenched, excavating means mounted to the framework and adapted to act along both sides of the pipe already laid onto the bed at least at the position of the framework, so as to form two trenches of predetermined depth, adjacent and parallel to the pipe itself, rippers or ploughs, adapted to disgregate the bed zone directly under the pipe, and a pump for the removal of the material excavated by the excavating means, wherein the framework comprises at least two skid members for the side support and the adjustment of the maximum excavating depth, said skid members being of adjustable height with respect to that of the excavating or dredging means;

• a first series of disgregating rippers, mounted to vertical rods, driven by levers actuated by ram units and movable between a rest position, in which the rippers are essentially parallel and laterally displaced with respect to the pipe, and an operating position in which the rippers engage the bed zone immediately below the pipe to be entrenched;
• excavating shovels, forming said excavating means, which are mounted in pairs symmetrically with respect to the framework and in the number of two or more shovels for each side of the framework, each shovel having an excavating edge at a level predetermined and lower with respect to the level of the excavating edge of the next preceding shovel with respect to the dragging direction of the framework;
• means for the adjustment of the distance between the two internal sides of the framework, said adjustment depending on the diameter of the pipe to be entrenched;
• a second series of disgregating rippers, which are provided at least in the fore part of the framework and protrude downwardly, in order to engage the bed before the dredging shovels.