Bahnumspuler mit verbessertem Perforiermechanismus.

摘要

An improvement in web-converting rewinders of the type which includes a perforator cylinder, and a bedroll/chop-off roll combination (21, 23) comprising a set of chop-off blades (31, 32), some of which chop-off blades (31) are disposed on the bed roll (21), and some of which (32) are disposed on the chop-off roll (23); and in which a running web is forwarded from an unwinding parent roll, and is converted into consumer product rolls such as, for example, tear-separable multi-sheet rolls of toilet tissue or paper towels. The improvement comprises parallel-motion chop-off blades (31, 32) which can be more closely spaced than in prior art chop-off blades, and thus induce greater stretching and more positive breaking of the web; and, preferably, the chop-off blades (31, 32) are disposed to act on a longer machine-direction-length of the running web than contemporary rewinders to enable more positively inducing roll endings by breaking along transverse lines of weakening rather than by inducing ragged transverse tears of web. Such a disposition of the chop-off blades (31, 32) is said to provide a wider window in which the lines of weakening in the running web may be indexed during each roll-ending chop-off event. Such an indexed relationship between the chop-off mechanism (20) and the running web is easier to continuously maintain with such a wider window, all other factors being constant. This invention is particularly useful for webs such as creped paper which must be stretched substantially in the machine direction before they will break along transverse lines of weakening such as lines of spaced cuts or lines of perforations.