| 摘要 |
PROBLEM TO BE SOLVED: To stably provide a minute tension which can be adjusted by a few grams. SOLUTION: A tension device is provided with a shaft 9 with an external thread at one end which is fixed on a plate 10, a pulley 20 rotatably mounted on the shaft 9, a spring fitted on the shaft 9 and pressing the pulley downward and a nut 11 screwed on the upper end of the shaft 9 to press the upper end of the spring 8. A sheet whose coefficient of friction of surface is smaller than that of the pulley 20 is fixed under the pulley 20 and a wire 5 drawn from a winding frame is wound on the pulley 20. |
