Method and unit for forming tubular lengths of web material, particularly in a labelling machine

摘要

An example includes a method for forming tubular lengths of web material. The example can include winding a portion of web material in a tubular configuration such that opposite vertical ends of said linear portion overlap. The example can include welding said overlapping ends to fix said linear portion of web material in sleeve configuration. This welding can include heating up at a first temperature a first region of said portion over the whole of which said ends overlap and heating up at a second temperature lower than said first temperature a second region of said portion adjacent to said first region, said ends of said portion of labelling web material overlapping over only a part of said second region. One or more examples relate to a forming unit configured to implement the method outlined above.

主权项

1. A unit for forming tubular lengths of web material, comprising:
a winding body to receive and wrap a portion of said web material into a tubular configuration with opposite ends overlapping, the winding body defining an axis; a sealing element comprising a rectilinear strip-like active working surface adapted to cooperate with said portion of said web material wrapped around said winding body to weld said ends so as to obtain a sleeve label, wherein said working surface comprises:
at least a first region and a second region, each region defined by a longitudinal strip region parallel to the axis of the winding body, having a height corresponding to a height of said working surface, and positioned substantially adjacent laterally to one another, independently and controllably heatable to respective first operative temperature and second operative temperature, said second temperature being lower than said first temperature,wherein said first region of said working surface is configured to cooperate with said portion of said web material wrapped around said winding body at a first corresponding sleeve label region, over the whole of which said ends overlap and said second region is adapted to cooperate with said portion of said web material wrapped around said winding body at a second corresponding sleeve label region, over a part of which said ends overlap; and an actuator assembly for moving said sealing element into and out of engagement with the overlapped edges of the web material wrapped around said winding body.