Apparatus for forming bags of thermoplastic material
AssigneeKarl Heinz Stiegler
InventorEhrhart Schulze
Life of this patent
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Abstract
In an apparatus for forming and separating the side edges of plastic bags of the type which have opposed interlocking closure strips, an intermittent transport device transports a half-tube of thermoplastic sheeting to a welding device. The sheeting is stopped while welding is performed. At a milling station upstream of the welding device, a milling apparatus is actuated while the half-tube is stopped to mill off a short length of each of the opposed closure strips at a position which coincides with the position at which welding will later be performed.
Claims10
An apparatus for the manufacture of plastic bags from half-tubes of at least one double-ply thermoplastic sheeting the two plies of which bear closure strips on facing inner edges thereof, to form a snap-fastener-like closure of the bag openings comprising:
- a welding station having a welding ledge which extends transversely to the direction of conveyance separating the individual bags from the sheeting by separation-welding;
- conveying means for feeding said sheeting to said welding station;
- a milling device upstream of said welding station;
- means for intermittently engaging said milling device with said closure strips whereby facing portions of said closure strips are milled off;
- and
- means for aligning said thermoplastic sheeting with said welding ledge at the location where said closure strips have been milled off.
Dependencies are inferred from the claim text.