They worked with hand trowels, a plywood form for lining the shaft with concrete, inch by inch, and a sturdy hand-builtcrank for lowering a man to the bottom and sending up buckets of sand.
The body is built from balsa wood, and the wings powered by a wire crank driven by a rubber band.
燕尾蝶的身体是用轻木做的，而翅膀的动力来源为用橡皮圈驱动的金属曲柄。
3
To research wear fault dynamic response for slider-crank of membrane pump, the wear fault dynamic model was built which based on the contact-separation state contact force model.