| 摘要 |
A dispenser sequentially dispenses web material from a working web roll and then a reserve web roll. A web sensing mechanism senses the presence of the working web at a back side of the main feed roller and introduces the leading end of the reserve web roll to a feed nip defined by two feed rollers immediately after the trailing end of the working web roll passes over a back side of the feed roller. Web sensing, and controlled introduction of the leading end of the reserve web to the feed nip, are carried out by a simple and effective interaction of a grooved main feed roller, and a pair of pivotable lever arms-a web sensing arm mounted at the backside of the rollers, and a transfer arm mounted at the front side. The mechanism avoids double feeding of web by sensing the presence or absence of web at the back-side of the main feed roller. Transfer fingers of the transfer arm are movable against the reserve roll web and into corresponding grooves in the main feed roller such that a leading end portion of the reserve roll web is reliably moved into the vicinity feed roller nip, where serrations provided in the edges of the grooves facilitate a gripping of the leading end portion to pull the web through the nip. The feed path is arranged to extend away from the transfer fingers so as to avoid interference of the transfer fingers with the subsequent feeding of the web.
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