Electric heating – Heating devices – Combined with pressure application means
Reexamination Certificate
2000-11-13
2002-10-29
Jeffery, John A. (Department: 3742)
Electric heating
Heating devices
Combined with pressure application means
C219S388000, C053S370700
Reexamination Certificate
active
06472638
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed at a method and apparatus for producing bags preferably from a roll film source and preferably for use in producing foam cushion bags.
BACKGROUND OF THE INVENTION
In the packaging industry, a variety of devices have been developed to automatically fabricate foam filled bags for use as protective inserts in packages. Some examples of these foam-in-bag fabrication devices can be seen in U.S. Pat. Nos. 5,376,219; 4,854,109; 4,983,007; 5,139,151; 5,575,435; 5,679,208; and 5,727,370.
In addition to the common occurrence of foam dispenser system lock up or poor mix performance in prior art foam-in-bag systems, the film supply, tracking, sealing and feed components of prior art foam-in-bag systems also represent particular sources of headaches for operates of prior art devices. The headaches include, for example, attempting to understand and operate a highly complicated, multiple component assembly for feeding, sealing, tracking and/or supplying film (often C-fold) to the bag formation area; high breakdown or misadjustment occurrence due to the number of components and complex arrangement of the components; high service requirements (also due in part to the number of components and high complexity of the arrangement in the components); poor quality bag formation, often associated with poor tracking performance, particularly with respect to C-fold film supply systems which have a different type of side edge arrangement (unconnected versus connected edge) that is inherently prone to difficult maintenance of good tracking characteristics; vent hole blockage and/or product contamination from foam exiting the vent(s); and lack of versatility in regard to vent length and vent location.
Another particularly problematic area associated with the prior art foam-in-bag system lies in the area of heated resistance wire replacement, both in regard to edge sealing and in regard to the cross-cutting sealing systems. In the prior art systems, there is often required delicate operator manipulation with certain tools to achieve removal and reinsertion of broken, or worn, heated wires (which is a common occurrence in the thin heated resistance wires used in the industry to form the seals).
In addition, prior art systems suffer from other drawbacks, such as relatively slow bag formation and a slow throughput of completed bags which, in some systems, is partially due to a reverse feed requirement to break an upper, no-yet-completely formed bag from a completed bag with one or both adhered by the bond formed between the earlier melted and presently cooled plastic material on the heated cross-cut wire.
SUMMARY OF THE INVENTION
The present invention is directed at providing a bag forming assembly which helps to avoid or lessen the effect of the numerous drawbacks associated with the prior art systems such as those described above. In so doing, the present invention presents a highly versatile machine that provides numerous advantageous features without invoking added complexity and added components, which is a common tendency in the prior art systems, particularly of late. These advantageous features of the present invention include, for example:
a) the formation of bags through use of a single supply roll source which is a two-ply supply roll containing a two layer supply of rolled independent sheets;
b) a dual function motor that acts to drive the drive roller of the present invention and, at the desired point in time, also drives a pivoting cross-cut bar to a cross-cut formation location from a standby location and vice versa, to avoid the requirement for a secondary activation system for forming the cross-cut and the added complexity associated therewith;
c) an automatic bag/cross-cut wire separation feature which avoids the common prior art requirement of providing a reverse feed movement in the bag film supply;
d) biased edge seal inserts which apply constant pressure against the side edges of roll film material being passed between the edge sealers and drive roller of the present invention for facilitating constant contact and for creating a drag effect which provides a self-cleaning function as tube film is dragged past the heated wire component of the heating unit;
e) an easily removable and installable pair of edge seal inserts for easy edge seal heat wire maintenance and which have a reduced electrical current/power source demand, and in a preferred embodiment, feature plug-in cartridge heat units for even easier edge seal heat wire maintenance;
f) a continuous and uninterrupted edge seal arrangement which is preferably adjustable with the driven roller and provides a non-leak seal for the full longitudinal length of the bag and preferably along both sides;
g) a vent former that is also preferably supported by the driven roller and preferably includes a heat cutter positioned inward of the permanent edge sealer and circumferentially above the edge sealer heat unit (and thus above the nip) so that the heat cutter cuts a vent in only one of the two plies such that foam contamination of packaged products can be avoided through strategic positioning as to which side of the bag faces the container and which side faces the product;
h) a vent former arrangement which allows for easily varied vent lengths, longitudinal vent positioning to suit specific packaging requirements, the option of forming a vent only on one side or on both sides, vent formation in only one face of a formed bag (a feature that provides advantageous versatility in contamination avoidance) and the ability to avoid edge fold over vent blockage, and the avoidance of seal breaks due to an inward positioning of the vent hole with respect to a continuous side edge seal;
i) a driven wheel/edge seal insert/vent former combination which is easily laterally adjustable together so as to achieve a desired opposite edge seal spacing and vent formation positioning for a variety of bag width sizes;
j) a downstream “pull down” feed system which avoids the complication of attaching a driver to the roll supply (typically an inserted roll core driver) and providing an active braking system, and which can utilize merely an inactive friction enhancement system in an upstream support roller;
k) a knurled driven roller pair which, together with a compression relationship with the drive roller, helps maintain a non-slip tension in the two-ply film stack being pulled down through the system;
l) a rapid bag formation and bag throughput system which is particularly advantageous for use with a high throughput foam dispenser system, to provide not only an increase in foam-in-bag formation production, but the ability to provide improved foam expansion efficiency (i.e., more ft
3
. in foam per lb. of chemical due to the avoidance of pouring new foam mix onto earlier poured and beginning to expand foam mix) as well as the benefit of being able to insert bags into an area of use before the foam-in-bag significantly converts from its cream state to a rapid rise state;
m) a control system that provides, partly in conjunction with the dual purpose single motor feature of the present invention, a highly efficient and easily manipulated roll-film bagger (e.g., bag length characteristics coordinated with the foam input timing and vent positioning and length options);
n) an easily serviceable cross-cut heated wire system which avoids inefficient service down time in a manufacture cycle as it provides an order of magnitude difference in cross-cut change time;
o) a significant lessening of the number of overall components due in part not only to the dual function motor described above, but also to other features such as the use of the drive roller itself as a back support means for the film supply being pinched by the cross-cut bar during the cross-cut/seal step of the present invention;
p) a compact system which is due in part to the lessening of components discussed above, placement of the dual function drive motor and one-way clutch within the interior of the drive roller, and the avoidance of a requirement for
Piucci, Jr. Vincent A.
Sperry Charles R.
Jeffery John A.
Sealed Air Corporation
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