Four-finger stack-stretch-wrapping machine - moves fingers in pairs horizontally and successively inwards and outwards and for different distances

摘要

Stretching sheet-material in hose form is extracted from a storage unit, parted off at the appropriate height and formed into a cowl. Four fingers sliding vertically and horizontally are inserted in the cowl, which is then folded into a bellows round them and stretched horizontally and pulled over the stack, keeping it clear of the latter's top edges, it being also stretched in the vertical direction before release. Before engagement with the cowl (17), two diagonally-opposite first fingers (13') are moved horizontally inwards for a first distance, after which the two others (13'') are similarly moved, but for a shorter second distance. After engagement with the cowl, the second fingers are moved horizontally outwards, followed by the first fingers. Inwards movement can be at a higher speed than outwards movement. ADVANTAGE - Simplicity, and requires little modification for use with cowls of different and particularly very small initial cross-sections.