Finger Clamping Unit: A Clamping Device with a Large Clamping Range

Abstract

Finger Clamping Unit (FCU) is a small-sized single-point clamp developed to clamp thin object of various thicknesses. It has a six-bar linkage with one compliant link, uses an electric motor as an actuator and induces toggle-lock motion by singular configuration. The main purpose of the FCU is to clamp car bodies in car assembly lines, while adapting to various thicknesses of car body. Unlike other clamping devices in the industry, it has a large clamping range (defined as the thickness range that the FCU can clamp). In this paper, the overall process of FCU development is presented. The six-bar linkage was chosen in type synthesis, and compliance was added for toggle-lock motion. Static analysis of the compliant FCU was completed, and results were plotted in a three-dimensional (3D) plot which expresses the behavior of the FCU. The lengths of each link were optimized in dimension synthesis. An FCU was constructed to reinforce the simulated results. The unique design of both the six-bar linkage FCU and the compliant link were presented. Simulated and experimental 3D plots were compared and analyzed. An appropriate friction model that best fits the experiment data was found. The advantage of the FCU—its clamping range—was proved by experiment.