Web infeed for a rotary printing press

摘要

A rotary beam has mounted thereon a pair of carrier arms for rotatably supporting a roll of web from which the web is fed into the press, and another such arm pair for supporting another such web roll to which the web is to be spliced upon consumption of the first web roll. One of each pair of carrier arms has rotatably mounted thereto a hollow spindle to be partly inserted in the tubular core of the web roll. The hollow spindle has detents arranged at circumferential spacings thereon for fluid pressure actuation into frictional engagement with the inside surface of the web roll core. The other of each carrier arm pair has a second spindle rotatably mounted thereto which is to be held endwise against the web roll core via a spring-loaded end cap. How hard the web roll core is urged against the first spindle by the second spindle, resisting the unwinding of the web therefrom, depends upon whether the second spindle is held fast against the end cap or spaced therefrom by the spring. The second spindle is sprung away from the end cap upon decrease of the web roll diameter to a predefined limit, in order to mitigate tension on the web being paid out.