A triangular nomogram for spherical symmetric coupler curves and its application to mechanism design

This paper presents a triangular nomogram for spherical symmetric coupler c urves generated by a spherical crank-rocker with special dimensions. The pa per also illustrates the application of this nomogram for spherical mechani sm design. The expression of symmetric coupler curves traced by the spheric al crank-rocker is derived. A computer program is developed to calculate th e coordinates of the coupler curve points for the prescribed dimensions of the mechanism. According to the classified properties of coupler curves obt ained a triangular nomogram for spherical symmetric coupler curves can then be constructed by using three design parameters, i.e., length of crank, le ngth of fixed link, and coupler angle. The triangular nomogram provides an alternative selection for dimensional synthesis of spherical path generator s. The synthesized mechanisms can also be rued to provide initial estimates for optimal synthesis of spherical path generators. A design example is pr esented.