Chebyshev linkage

It was invented by the 19th-century mathematician Pafnuty Chebyshev, who studied theoretical problems in kinematic mechanisms.

[1] The motion of the linkage can be constrained to an input angle that may be changed through velocities, forces, etc.

Regardless of the input angle, it is possible to compute the motion of two end-points for link L3 that we will name A and B, and the middle point.

The limits to the input angles, in both cases, are: Chebyshev linkages did not receive widespread usage in steam engines,[citation needed] but are commonly used as the 'Horse head' design of level luffing crane.

In this application the approximate straight movement is translated away from the line's midpoint, but it is still essentially the same mechanism.