A bulldozer is a compound machine that is made up of several individual simple machines, including levers, wheels and axles, pulleys, gears, wedges and screws. A simple machine is any component that is used to multiply and direct a force.
The bulldozer is a combination of several individual simple machines that work together to complete excavation and path-clearing jobs. The bulldozer moves over rough terrain thanks to the wheels and axles of its tracks. The blade of the bulldozer is a wedge that is used to push sand, soil and debris. Depending on the angle of inclination of this blade, the bulldozer can either push objects from one place to another or simply move them out of its path, clearing the way for other excavation equipment. The claw-shaped ripper that some bulldozers have on their backs is also a collection of individual wedges. This ripper is a large rake that breaks and separates the surface that the bulldozer is treading on so that it can later be removed.
The entire compound machine is held together using screws, another type of simple machine. The gears that transmit power in the drive train of the bulldozer are also simple machines. These gears are used to transmit and multiply torque to enable the bulldozer to go up steep inclines.