Watt Linkage: Mechanism and Application

Watt linkage is also known as the parallel linkage. James Watt invented Watt mechanical linkage. In Watt’s linkage central moving point of is constrained to travel on an approximation to a straight line. Watt’s Linkage can be found in some automobile vehicles at suspensions that allow the axle of a vehicle to move vertically while preventing sideways motion.

Application of Watt’s Linkage:

Watt’s linkage mechanism is used in the rear axle of some car suspensions as an improvement over the Panhard rod. This mechanism is used to prevent relative sideways motion between the axle and body of the car. It approximates a vertical straight line motion more closely and does so while locating the center of the axle rather than toward one side of the vehicle, as commonly used when fitting a Panhard rod.

Panhard rod consists of two horizontal rods of equal length mounted each side to the wheels of an automobile. At the center of Panhard rod, a vertical bar is connected. The center of this vertical rod the point which is constrained to move in a straight line motion is mounted to the center of the axle. All pivoting points are free to rotate in a vertical plane.

Watt linkage can be seen in the rear suspension of above animation as two Panhard rods mounted opposite each other.