treadle
noun [ C ] uk/ˈtred.əl/ us/ˈtred.əl/
（带动机器中轮子转动的）踏板
a part of a machine that, when operated by the foot, gives the power to turn a wheel in the machine
My grandmother still uses her old treadle sewing machine. 我奶奶仍然用着她那台老掉牙的脚踏缝纫机。
Compare: pedal noun