A turntable and a top-pushing rod, wherein said turntable is provided pivotally at equal interval along its peripheral direction with a plurality of rod bodies, and wherein said rod bodies are provided at their ends near the periphery of the turntable with heavy blocks, while said rod bodies are engaged at their front ends near the center of the turntable with a spring that has its other end engaged on the turntable, thereby the swinging of said rod bodies would drive springs to stretch or contract; wherein, said top-pushing rod is driven by a motor such that said top-pushing rod can move reciprocally along a linear direction in which it can push the heavy block on a rod body above said turntable so as to bring said heavy block returning to the highest position of the turntable.