Pitman arm

Pitman arms are commonly found in water pumping windmills, automotive steering systems, and sewing machines.

It translates the rotary power from the wind blades to the up-and-down motion of the pumping arm.

It transmits the motion it receives from the steering box into the drag (or center) link, causing it to move left or right to turn the wheels in the appropriate direction.

"Pitman arm" can also refer to a component in a treadle sewing machine that connects the foot pedal to the crankshaft of the lower flywheel.

In this case, the Pitman arm works similarly to a connecting rod in an engine in which the up and down force applied at one end of the arm translates to pushing and pulling alternately on the eccentric part of the crankshaft to achieve continuous rotation of the crankshaft and flywheel.