| 摘要 |
A web transfer mechanism provides, in a flexible sheet material dispenser, automatic transfer of web feed from a working roll to a reserve roll, using a sensor plate operatively coupled with a transfer arm. A sensor plate providing a pivotable stub roll receptacle cover senses the absence of web from the stub roll at a pre-feed portion between the stub roll and a feed roll nip to activate a transfer of feed to the web of a reserve roll. The transfer is initiated by a transfer arm that advances the reserve web into the proximity of the feed roller nip. The pre-feed sensing position of the sensor plate makes the web transfer mechanism well suited to adaptation to known dispenser types including a web cutting knife which emerges from within the feed roller. At the same time, double feed of web material at the time of transfer is minimized. In a second aspect, a movable front shield opens automatically upon opening of the outer dispenser cover, presenting an opening for pre-transfer placement and retention of a leading edge of web material from the reserve roll. Upon closure of the dispenser cover, the front shield returns to a closed position placing the transfer arm in a pre-transfer set position. <IMAGE> |
