Deep water pile driver

Abstract

A pile driver is provided for use in deep water with a remotely operated vehicle (ROV) and a working ship for setting piles, pin piles and well conductors in subsea soil and for soil sampling in deep water and can be used for shallow water and land-based applications. A ram mass or hammer is received in an open frame and hydraulically reciprocated while in contact with water. A piston rod received in a piston cylinder is secured at one end to the hammer through a coupling mechanism, and an external source of hydraulic power is used with an on-board hydraulic circuit. Gas is compressed during an up-stroke to store energy, which is released during a down-stroke to push the hammer downwardly. The coupling mechanism provides a connection between the piston rod and the hammer that can move between an essentially rigid lift connection, an essentially rigid downward-push connection and an essentially non-rigid impact connection for preventing buckling of the piston rod when the hammer strikes at its lowermost point. One embodiment of the coupling mechanism includes a hollow body having opposing longitudinal slots, a rod slideably received in the hollow body that is pinned slideably at one end in the opposing slots and pinned fixedly at the other end to the hammer, with a spring in the hollow body providing a bias to push the rod toward the hammer.