On the Motions of Four Pagoda Clocks in the Forbidden City

Ancient mechanical clocks and automatons are solid evidence regarding the evolution of technological development. At least four ingenious eighteenth-century clocks with pagoda automatons are preserved in the Palace Museum in Beijing. Two were made in China, the other two in Britain. Although the internal mechanical components were maintained and recorded in the late twentieth century, their mechanism structure is mostly not made available to the public owing to the historical value of these artefacts. This study introduces feasible mechanism structures for the four pagoda automatons based on published works, along with considerations of mechanical design. Five subsystems of the clocks are analyzed, and two mechanisms of the pagoda automaton are illustrated. In particular, feasible mechanisms of the four pagoda automatons for raising their stories are explained. The analysis procedure presented in this paper expands the feasibility of reconstruction work on ancient mechanisms with unknown structures.