How does the toggle action work?

What is a Toggle Clamp?     

      Toggle clamps operate on a simple mechanical principal and are used to fasten objects instantly, especially for jigs and fixtures. Typically, a toggle clamp consists of: A handle to operate the mechanism and a clamping arm to hold the work-piece Linkages to multiply the applied force and a base to mount the clamp to a work bench or other surface.

How does the toggle action work?   

      Toggle action clamps operate through a linkage system of levers and pivots (fulcrum). The fixed-length levers, connected by pivoting pins, supply the action and clamping force. The toggle action has a lock point which is a fixed stop and linkage. Once in the lock position, the clamp does not unlock unless the linkage is moved/released. Although oriented in different ways, most toggle clamps are designed using this basic principle.