Mechanisms

Parallel Crank

equal and // crank lengths; coupler and ground are same length and parallel; railway train wheels

Nonparallel Equal-Crank

Cranks are = in length but not //; coupler is the length of the mounts of the cranks; approx gear sys

Crank and Rocker

One crank rotates 360, the other oscillates; windshield wipers

Four bar complete rotation (quick return)

Both cranks rotate 360, but the follower at varying speeds; cutting machines

Slider crank

Really only 3 links; rotational motion to rectilinear; gas engine; offset version has slight increase in return speed

Scotch yoke

Turns rotational motion into sine wave rectilinear; shaping machines and valve actuator

Quick return

Slow forward stroke and fast return stroke; shapers and saws

Drag link

Four bar linkage with two joints and a slider. Similar to a quick return mech.

Watt's mechanism

Middle point moves in an approx line

Evans Grasshopper Mechanism

Linkage is drug against wall in approx line

Scott-Russell Mechanism

Triangle with sliding foot and extended arm that traces exact line

Robert's mechanism

M shaped mechanism that approx line

Chebyshev's Mechanism

Straightjacket shaped linkage where the "sternum" moves in an approx line

Peaucellier/Lipkin

Kite shaped, complex mechanism that makes exact line

Slider crank toggle

Crank turns and applies a huge force over a very small distance

Oldham coupling

Sliding coupler that allows movement in the radial plane

Universal/Hooke's joint

Connects angled shafts at a varying angular speed.

Geneva Wheel

Very sudden, discrete turns from rotational input

Differential screw

Two connected screws with slightly different threads to create slight movement