Envelopes – wrappers – and paperboard boxes – Wrapper – Bottle
Patent
1979-10-10
1982-12-14
Garbe, Stephen P.
Envelopes, wrappers, and paperboard boxes
Wrapper
Bottle
206390, B65D 2710, B65D 3000
Patent
active
043634370
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a web of bags according to the introductory part of claim 1 as well as to a method and a device for the production of such a web of bags.
In trade, there are obtainable webs of bags which are wound into rolls and where consecutive single bags are attached to a carrying strip. The bags are folded flat on the roll but can be opened and inflated, for the introduction of articles into the bags, by the application of an air flow. The air flow lies substantially in the delivery plane of the folded bags and is directed towards the bag edge which bounds the later filling aperture. The slit provided on the upper bag edge serves for allowing the bag to be blown up from the delivery plane into an oval or round shape. The latter is determined by guides on conventional machines for the packing of articles where use is made of webs of bags.
In practice, it has turned out that not all of the bags open properly when an air flow is applied to such a known web of bags; often up to 20% of the bags remain closed.
The invention therefore aims at providing a web of bags whose individual bags can be reliably opened by the application of an air flow. There is furthermore to be indicated a method for the production of such a web of bags and a device for the performance of such a method.
It has turned out in practice that on a web of bags where, according to the invention, the bags are provided with the slit at the rear edge, as viewed in the delivery direction during packing, the bags are opened and inflated with great reliability by the application of an air flow. This is presumably due to two reasons:
On the known webs of bags, the bag sections adjacent to the slits are pushed and are braked by frictional forces which are brought about by the machine guide supporting the bags. This involves the risk of these bag sections being turned over. The bag will then be folded exactly at that portion of the filling aperture where it is meant to be opened by the air flow. By contrast, on the web of bags according to the invention, the bag sections adjacent to the slits are dragged. They are thus drawn outwardly in the desired manner by the friction prevailing on the respective guides of the packing machine; a bag section adjacent to the slit and initially turned over is even turned back again.
In the very first inflation phase, a portion of the bag rear wall section adjacent to the slit is initially increasingly pressed against the machine guide, which is located therebehind, by the onflowing air. On the known web of bags, where this section of the bag rear wall is pushed under friction, this leads to a force counteracting the opening movement. On the web of bags according to the invention, where the corresponding wall section is drawn, such a force inhibiting the opening of the bag does not arise.
Advantageous further developments of the invention are indicated in further claims.
On a web of bags according to the invention, the individual bags can be cut off within a range of tolerance of the same thickness of material. In a further development of the invention, the dimensions of this range of tolerance are specified by the dimensions of the interspaces, and in a further development of the invention, they are specified by the dimensions of the additional notch.
On a web of bags according to the invention, the opening of the bag can be ensured, even under very unfavourable conditions, in that a jet of air which is vertical to the delivery plane passes through the hole in a bag onto the bag front wall and thereby lifts this latter from the rear wall.
If, according to the invention, the hole is provided at the end of the slits, then it can be produced together with these in a simple manner and simultaneously bounds the slits so that these are not torn to any further extent under tensile forces, since no slit effect is provided at the end of the slits.
A web of bags according to the invention has a single-layer carrying strip. On the known webs of bags, the carrying strip consists of two heat-sealed layers. However, t
REFERENCES:
patent: 3779449 (1973-12-01), Membrino
patent: 4021283 (1977-05-01), Weikert
Garbe Stephen P.
Philpitt Fred
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