在15世纪早期，人们发明了螺旋弹簧或均力圆锥轮，尽管它的主弹簧的张力不断变化，但仍能对计时装置的齿轮保持恒定的力。
In the early 1400s came the invention of the coiled spring or fusee which maintained constant force to the gear wheels of the timekeeper despite the changing tension of its mainspring.
该装置将试样通过上、下夹头安装在主承力框架内，利用弹簧对试样施加轴向载荷，使试样承受恒定的拉伸应力。
The specimen was put in framework by top and bottom fixture and constant tensile load was applied by spring.
斜置式对称分布的主振弹簧，使得振动筛在运行时平和稳定，隔振效果极好。
The tilting symmetric distributed main-vibrating spring makes the vibrating screen smooth during operation and vibration isolation effect is very good.
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