| 摘要 |
This relates to a dancer roll assembly wherein there are a pair of dancer roll assemblies disposed in side-by-side relation and each vertically disposed. Each dancer roll assembly includes an upper shaft and a lower shaft having spaced sprockets thereon which are vertically aligned and over which are engaged belts. Each pair of belts carries a dancer doll for vertical movement under the influence of a tensioned web passed around the dancer roll. The upper shaft is a control shaft and has connected thereto a pneumatic control motor which resists the rotation of the shaft and thus resists the upward movement of the dancer roll. After the dancer roll has moved to an uppermost permitted position, the pneumatic motor is actuated to rotate the upper shaft and thus return the dancer roll to its lowermost starting position. The tension on the web is controlled by controlling the air pressure to the air motor.
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