Numerical and Experimental Design Optimization of Toggle Clamping Mechanism

Abstract

Toggle mechanism is commonly used in manufacturing industry for several applications ranging from injection molding machines to tools and fixtures. Toggle clamps are available in numerous types to outfit specific applications. This paper explores the design optimization of the toggle clamping mechanism. Toggle mechanism considered here is actuated by hydraulic cylinder used in CNC bending machines. Force amplification ratio is the key design parameter of toggle clamping mechanism. Performance of toggle clamp mechanism is based upon the force available at the clamping location which is output link. Clamping force available at the output link is the function of the input cylinder force, geometric position of all the links, coefficient of friction between moving and turning parts. Hydraulic cylinder is available in different standard sizes and is operated on specific system pressure. Input cylinder force is the function of cylinder size and the system operating pressure. Mathematical modeling of the toggle clamp mechanism is presented in this paper. Analytical approach and computer-aided design model force analysis are also carried out. Resulting clamping force computed from the analytical approach is compared with the CAD model analysis. The ultimate aim of this work is to develop a new toggle mechanism to reduce the input efforts to get the same output as in existing toggle clamping mechanism.