ABSTRACT
In this chapter, the author briefly discusses some of the frequently useful results with reference to coupler curves of a 4R linkage. The most useful information for a designer, regarding the coupler curves of crank-rocker linkages, is contained in the Atlas of Hrones and Nelson. This atlas contains approximately 7000 coupler curves of various shapes. Multiple points such as crunodes and cusps may occur in a coupler curve. Since the existence of such points can be utilized by a mechanism designer, a brief discussion of such points in a coupler curve is in order. The cusps in coupler curves are used in different mechanisms in order to generate a reversal without impact and shock. A crank-rocker mechanism can always be designed to generate two cusps in a coupler curve, at two prescribed locations, with prescribed amount of crank-rotation as the coupler point moves from one cusp to another.
