| 摘要 |
PROBLEM TO BE SOLVED: To provide a tension device for adjusting back tension plural steps or steplessly. SOLUTION: A tension device, for imparting tension to a wire rod W by engaging with the rod W moving from the supply source of the rod W to the treating device for the rod W, has a back tension pulley 107 for engaging with the rod W, imparting pulling force to the rod W, and movable in a given direction, first and second springs 129 and 135 for energizing the pulley 107 in a given direction, and an air cylinder 138 for canceling the energizing force of the spring 135, consequently tension imparted to the rod W by the pulley 107 can be changed at plural steps because of the variation of the energizing force of the spring in accordance with such canceling.
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