Patent ID: 8608409

Claim:
A pile driver for driving foundation piles, comprising: a gantry-type frame, in turn comprising a horizontal base resting on an underlying foundation structure, two uprights extending upwards from the base, and a horizontal top member connecting the two uprights; a first movable body which is located between the two uprights and slides along the uprights; a first lock device fitted to the base and which, in use, rigidly engages a connecting member of the underlying foundation structure; a second lock device fitted to the first movable body and which, in use, rigidly engages a shaft of a pile to be driven; and at least one first hydraulic jack to move the first movable body along the uprights, the first hydraulic jack comprises a cylinder connected rigidly to the first movable body and a piston fixed at the top end to a bottom surface of the top member of the frame; wherein the first lock device comprises a through first hole formed through the base and tapering downwards; a number of first wedges, each of which is sector shaped and inserted, in use, inside the first hole; and a first actuating device for raising the base of the frame with respect to the underlying foundation structure; and wherein the second lock device comprises: a through second hole formed through the first movable body and tapering upwards; a number of second wedges, each of which is sector-shaped and inserted inside the second hole; an annular supporting plate located beneath the first movable body and supporting the second wedges; and a second actuating device supporting plate towards for moving the first movable the body.