This paper presents kinetostatic modeling of a compliant mechanism for translational motion. This mechanism arranges all compliant members in an inverted way, which enables the robustness against beam buckling due to the heavy payload. To enable quick design and analysis of the mechanism, a nonlinear analytical model is then derived based on the chained beam constraint model, which is validated by nonlinear finite element simulation. Geometric parameter optimization is further carried out for desired motion characteristics. Finally, a prototype is fabricated and tested to verify the analytical model.