| 摘要 |
Apparatus for continuously supplying a web of sheet material wound on rolls includes a conveyor which carries a roll from a loading station to a splicing station and then to an active or running station. While a running web is being drawn off a roll at the active station, a standby roll is loaded on the conveyor at the loading station and then it is advanced to the splicing station. A stationary core brake located at the active station is responsive to the tension of the running web and applies a drag to the core on which the web of the active roll is wound to maintain the tension at a selected level. When the web on the active roll is nearly exhausted, an endless belt in frictional engagement with the standby roll is driven by a motor and accelerates the roll until the peripheral speed of the latter is equal to about 99 per cent of the linear speed of the running web and then the belt is driven from the running web so that the two speeds match. At that time, the web of the active roll is spliced to the web of the standby roll, which thus becomes the new active roll, and the core brake stops the core of the first active roll. Simultaneously, a stationary brake responsive to the tension of the web running from the second active roll applies a drag to the periphery of the latter through the belt to maintain the tension in the new running web. As the new active roll is advanced to the active station, the belt moves with it so that the belt brake continues to control the tension of its web. The belt brake continues this control until the new active roll is in the active station and the core brake is engaged with the roll and energized at which time the belt brake is simultaneously deenergized to complete the transfer of the running web from the first roll to the second.
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