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For a general configuration of the mechanism:
- Note that points A, F and H are the instant centers (centers of rotation) for links AB, DF and GH.
- Because of this, the paths of B, D, E and G are circular arcs, as you can see in the animation below. The velocities of these points are tangent to their circular arc paths.
- Draw perpendiculars to the velocities of B and D. The intersection of these two perpendiculars defines the IC for link BD.
- Draw perpendiculars to the velocities of E and G. The intersection of these two perpendiculars defines the IC for link GE.
- The locations of these two ICs will guide you to the establishment of the relationships between the angular speeds of the links to the angular speed of input link, AB. It also guides you in determining the direction of rotation for each of the links.
For the configuration posed in this problem (shown below), where are the ICs for the links of the mechanism? Do you see the relationship between the location of these ICs and the directions of rotation for the links? Do you see the relationship between the location of these ICs and the speeds of the various pin joints in the mechanism (e.g., vD > vB and vE > vG)?