The power machine is run by a foottreadle and USES a knee lift to raise and lower the presser foot.
工业缝纫机是通过压脚启动的，用膝盖运动抬起压脚或降落压脚。
2
The foot bar is that part which differs it from other scooters. Customers just need step on treadle to make it glide, no need drive the ground.
这个踏杆就是酷步车与其它滑板车不一样的地方，只需踩动踏杆就可以连续滑行，无需蹬踩地面。
3
A Bellows operated by an assistant or by a foottreadle provided the forced draft for raising the temperature of the fire. Later, a waterwheel or animal power was often used to operate the Bellows.