Non-impacting pile driver

DETAILED DESCRIPTION The general object of the present invention is to provide a pile driver of the non-impact type, capable of being used safely alongside a building that is structurally damaged, or near a laboratory or the like where impact shocks, vibration and noise cannot be tolerated, and capable of driving standard length sections of pile pipe.
It is also an object of this invention to provide a selfcontained non-impact pile driver that can drive pilings in close proximity to the walls or footings of existing structures to provide for underpinning them, and which does not depend upon an existing building or set of pilings for reaction support, to thus be capable of operating at any desired distance from existing structures.
A further object of this invention is to provide a nonimpact pile driver with which pilings can be driven down to the point where they encounter a predetermined resistance and with which measurements of resistance can be readily made from time to time, as desired, while a pile is being driven.
Another and more specific object of this invention is to provide a non-impact pile driver comprising a large diameter long stroke ram and means whereby the ram can be moved down along a mast in steps as a pile is being driven and whereby the ram can be releasably locked to the mast at each step, all without need for the presence of an operator near the ram, thus affording a high degree of safety in the operation of the machine.
These and other objects of the invention that will appear as the description proceeds are achieved in the non-impacting pile driver of this invention, which comprises a chassis having ground engaging means for engaging the ground at a plurality of spaced points to provide a stable base, and a mast secured to the chassis and comprising a pair of laterally spaced opposite and upright guide rails.
A carriage having opposite side portions that are slidably engaged with the guide rails is thereby confined to vertical movement along the mast.
The carriage carries a hydraulic ram comprising a cylinder that is fixed to the carriage with its axis upright and between the guide rails and a piston rod projecting downward from the cylinder that is axially extendable and retractable relative to the cylinder and the carriage through a stroke of predetermined length