| 摘要 |
An apparatus for controlling the tension of a web material passing through a web-fed printing press includes two parallel shafts, at least one of which can be rotatably driven, and four rings, with two of such rings being spaced apart and fixed to the ends of each shaft. The casings of the two rings fastened to one of the upper and lower shafts is made of an elastically resilient material and includes slots. Each ring having a slotted casing further includes spreading elements disposed beneath the slotted casing for adjusting the diameter of the slotted casing, thereby partially controlling the tension of the web material passing through the gaps.
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