The Design of a 10-bar Linkage for Four Functions Using Symech

This paper describes a case-study which illustrates the capabilities of a commercially available software package called SyMech, which runs within Pro/ENGINEER. The software allows a designer to synthesize arbitrarily complex planar mechanisms by sequentially specifying one of three basic mechanism design functions: position, path, or angle. Because the software runs directly within Pro/ENGINEER, the designer can create the geometry of all of the parts during the mechanism synthesis process, greatly reducing the overall time and effort involved in the design process. INTRODUCTION The case-study begins by specifying a realistic (if not typical) industrial problem: create a mechanism that will move a finger (rigid body) inside a container to press a switch on the outside of the container, and then return to the inside of the container. This finger mechanism will be a four-bar mechanism created with position synthesis. Next, another four-bar mechanism created with position synthesis will be designed to open the cover of the container. The two independently designed four-bar mechanisms will then be linked together using angle synthesis. Finally, crank synthesis will be used to design an input driver, so that the entire mechanism can be driven with a continuously rotating input. 1 Two different solutions to this basic problem can be found in [Erdman and Sandor]. The complexity of this example not only highlights the utility and versatility of SyMech’s synthesis and analysis capabilities, but clearly illustrates the importance of subdividing the overall requirements into a manageable sequence of discrete mechanism design functions. The completed Pro/ENGINEER model of the linkage is shown in Figure 1. Figure 1. Completed ten-bar linkage.