Abstract: A machine for driving and extracting piling and the like having a horizontal support member and frame coupled so that the frame may move toward and away from the support member in a vertical direction, a pair of races located side by side in the frame and defining a corresponding pair of paths of travel spaced horizontally from each other and located in a common vertical plane, a relatively heavily weighted roller mounted for rotation within each race, each roller being rotatable about a horizontal axis perpendicular to the common vertical plane, means for rotating the weighted rollers in synchronism such that the horizontal components of the forces generated on the frame by the rollers cancel one another and the vertical components of the forces are in phase to thereby simulate the impact of a conventional reciprocating pile hammer.

Abstract: Power hammers for driving piling, and the like, free of any complex valve mechanism likely to require attention and comprising a working cylinder having an anvil at the lower end thereof and a ram operative as a piston in the cylinder, cooperative with the anvil and surrounding walls of the cylinder to form an expansion chamber, the ram having a passage extending from an annular groove intermediate the ends of the ram, down through the lower end to the expansion chamber and the cylinder having pressure supply and exhaust ports to register with the passage and to be uncovered by the ram, in lower and upper positions of the ram in the cylinder, whereby the essential functions of the hammer are automatically effected in the normal operation of the ram. Pressure controlled valves may be added to automatically hold desired pressures and release opposing pressures on the ram.