Effects of design parameters on geared two-link mechanisms

The design of a specialized agricultural harvesting machine required the use of a path generation mechanism that was compact, accurate, inexpensive to produce, and easy to operate. Previous attempts involved the use of a cam and follower, but they were expensive to manufacture and difficult to operate. This paper discusses an alternative method of using a coupled, open loop, two-link mechanism to generate a polygon-like closed path (pseudo-polygon) with an integer number of curved sides and apexes. A complete development of the path and path curvature equations are presented. The influence of the design variables on the coupler shape (flatness of each side) is shown in equation and design chart form. An example of a successful application of this design method applied to a plant cutting mechanism is presented.