A pile driver consists of a guide frame and a hammer. The guide frame keeps the pile (foundation element) aligned at the desired inclination, while the hammer drives the pile into the ground. Modern pile hammers are often two-stroke diesel engines using gravity to draw the piston down do create compression. Some pile hammers are steam-driven, and various methods of lifting and dropping dead weights using pulleys are still in use.
In modern practice, most pile drivers are suspended from cranes during driving operations, to allow easy movement of the pile driver around the jobsite.