2) Linkage System - Bolt Cutters

The nodes chosen in the above figure reflect selected areas of interest. Nodes are set on the middle of both handles as well as the jaws, because that is where load is expected to be applied. The handles, links 1 and 2, are connected by a pin joint and are connected to a jaw, link 4 and link 3 respectively. These jaws are connected by the fifth and final link, again by pins.

One interesting aspect of these bolt cutters is that prior to making contact with material between the two jaws, the device has two degrees of freedom.

However, following contact between the jaws and the object to be cut, friction couples the horizontal movement of both jaws, restricting the mechanism to one degree of freedom.

In this configuration, the linkage is now mirrored, meaning each link is translating in tandem with its mirror in the X direction and translating with equal magnitude and in the opposite direction of its mirror in the Y direction.

Because of this relationship, we can simplify the mechanism to a 3 bar linkage for kinematic analysis.