ABSTRACT
Now that we have learned to classify the various types of fourbar linkage, we will turn our attention to linkage design, to accomplish a specified motion. Designing some types of linkages (e.g. the threebar and the slider-crank) is quite simple and will not be discussed here. Creating an appropriate fourbar linkage is more challenging, and that will be the focus of this chapter. The general problem statement is as follows: given a set of specified positions, design a fourbar linkage such that a portion of one of the links passes exactly through these positions as the crank makes a revolution. An example of such a scenario is shown in Figure 2.1. For this problem, we would need to find the lengths of each link such that the line AB passes through positions 1, 2, and 3, in order. In most cases, the line AB is attached to the coupler, since the coupler is capable of complex motion. But if the desired motion is a pure rotation then we may decide to attach line AB to the rocker instead.
