Synthesis of Four-bar Motion Generation Considering Worst Case Joint Tolerances
Abstract— Four-bar motion generation is used to synthesize a mechanism which passes through or approximate prescribed rigid-body positions. This work will discuss the motion generation of four-bar mechanism with position tolerance variations due to joint running clearance. The tolerance variations study will be based on the standards of American National Standard Institute (ANSI). The new design constraint introduced in this paper will consider the joint tolerances and incorporate it into the displacement position matrix of coupler points described in the conventional planar four-bar motion generation models. The synthesized planar four-bar mechanism will produce tolerance limits for moving pivots and link length from which any mechanism can be synthesized to satisfy the prescribed coupler points with their prescribed tolerances. The included example demonstrates the synthesis of a four-bar mechanism with joint tolerances. 1
On the synthesis of a geared four-bar mechanism
This paper presents an analysis and synthesis method for a certain type of geared four-bar mechanism (GFBM) for which the input and output shafts are collinear. A novel analysis method is devised, expressions for the transmission angle are derived and charts are prepared for the design of such mechanisms. It is observed that the GFBM considered is inherently a quick-return mechanism. Large time ratios can be obtained with acceptable force transmission characteristics. During the working stroke, approximately constant angular velocity at the output link is observed. For the type of GFBM analyzed, direction of rotation of the input link affects the force transmission characteristics.
Syntheses of planar and spherical geared five-bar function generators by the pole method
Abstract While the pole method has been applied for problems of synthesizing planar and spherical four-bar function generators in previous investigations, we are extending the method to the synthesis of planar geared five-bar function generators, by means of an inversion linkage concept. For spherical geared five-bar function generators, we make use of the equations and formulas previously derived for body guidance as these are already available. However, we shall use the location of the relative poles for the orientation of the coordinate system to simplify the synthesis equations. Numerical examples are given.