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.
Laminar heat or mass transfer in rectangular channels and in cylindrical tubes for fully developed flow: comparison of solutions obtained for various boundary conditions
Abstract A comparison is made of results obtained with various boundary conditions at the wall of the channels. By comparing blood Sherwood numbers for finite wall resistance with those for constant concentration boundary condition only a small variation is found for various points along the blood channel.