Patent Application
20050113233
The present invention relates to packaging machines and more particularly to apparatus that deliver to packaging machines strip material which is formed into bags by the packaging machine.
One form of packaging includes a bag of generally of square or rectangular configuration having flanges at each longitudinal corner. Typically such bags have a “block bottom” so that they stand upright with the flanges extending upwardly.
Machinery that produces the above discussed bags are intermittent in motion. More particularly, the flanges are formed by halting movement of the film and welding the flanges while the film is stationary.
The above discussed apparatus have a number of disadvantages including slow operation as the dwell time for the welding process is time consuming. A further disadvantage is the complexity of the machinery and problems associated with the heaters that form the welds. A still further problem is that frequently the seals in these bags fail as product dropping into the bags ruptures the flanges.
In the above mentioned apparatus it should be noted that the bag material is formed into a tube and then subsequently formed so as to have longitudinally extending flanges. Accordingly, the flanges are formed downstream (after) the bag material has passed the former.
Described in UK Patent Application 2357991 is a bag in which folds are disposed inwardly of the bag to reinforce the bag. A folding apparatus forms folds in the strip bag material, with the folded strip bag material being delivered to a former so that the folds are located internally of the former and do not engage the forming surface of the former. The bags so formed have the disadvantage of reduced area available for printing. A still further disadvantage is that the folds project inwardly of the former and can inhibit the delivery of product to the interior of the tubular bag material. When forming bags with longitudinal flanges, correctly locating the flanges is difficult. This problem is exacerbated when the flanges are inside the bag material. A still further disadvantage is the problem of transversely sealing the bag material. With the folds inside the bag material the sealing jaws engage a layered construction consisting of six layers. Accordingly, the probability of a defective seal being formed is increased. This problem will be exacerbated where stripping is required as product may be difficult to move from the scaled area due to the layered construction.
It is the object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages.
There is disclosed herein an assembly including folding apparatus, through which strip material passes along a predetermined path to be longitudinally folded, and a former to which the strip material is delivered to font the strip material into a tube having longitudinally extending folds, the apparatus including:
a plurality of transversely spaced folding slots extending generally parallel to said path and through which portions of the strip material to be folded are moved;
a press member operatively associated with each slot to press each strip portion into a respective one of the slots to form a fold;
a fold former associated with each slot to engage the folds passing therethrough to deform the folds so that the folds maintain their configuration; and wherein
said former is operatively associated with said folding apparatus so that said folds are on the exterior of said tube.
Preferably, said former has a forming surface over which the strip passes, and wherein said folds contact the former surface
Preferably, each press member is of a circular configuration that rotates as it presses the strip material into the associated slot.
In an alternative preferred form, each press member is a blade that extends into a respective one of the slots to press the strip material into the slot.
Preferably, each fold former is a heated block having a longitudinal slot along which the folds pass to be heated there by.
Preferably, each fold former further includes rollers to engage the folds to secure portions to the folds together so that the folds maintain their configuration.
Preferably, the apparatus forms four generally parallel co-extensive folds.
There is further disclosed herein a combination to form tubular bag material having longitudinally extending flanges, said combination including:
a folding station through which strip bag material passes so as to he longitudinally folded so that the strip material leaving the station has longitudinally extending folds; and
a packaging machine former, operatively associated with the folding station, to receive the bag material with the longitudinally extending folds so that the former provides tubular bag material having longitudinally extending external flanges.
Preferably, said former has a forming surface that engages the strip material to form the tubular bag material, with said folding station being associated with said former so that said folds contact said former surface.
Preferably, the folding station includes a plurality of transversely spaced folding slots extending generally parallel to said path and through which portions of the strip material to be folded are moved; and a press member operatively associated with each slot to press each strip portion into a respective one of the slots to form a fold.
There is further disclosed herein a method of providing tubular bag material having longitudinally extending flanges, said method including the steps of:
providing a supply of strip material to be used to form bags;
moving the strip material from said supply and longitudinally folding the strip material so that the strip material has longitudinally extending folds; and
passing the strip with folds over a packaging machine former so as to provide tubular bag material having external longitudinally extending flanges.
Preferably, the former has a forming surface that contacts the folds.
Preferred forms of the present invention will now be described by way of example with reference to the accompanying drawings wherein:
In U.S. Pat. Nos. 4,663,917, 3,522,689, 3,070,931, 4,516,379, 3,629,987 and 4,524,567 there are various packaging machines described. These packaging machines have jaws which from discreet bags from tubular bag material. The tubular bag material is formed from strip material delivered to a former 30 (
The strip material delivered to the former 30 comes from a roll.
In
The bag 10 is formed from strip material that passes through a packaging machine such as the above mentioned packaging machines.
The bag 10 is formed from a strip 17 shown in end elevation in
The strip 17 is longitudinally folded at a folding station by means of a folding apparatus 20. The apparatus 20 receives unfolded strip 19 from a roll and forms the longitudinally extending folds 18 so as to provide the strip 17.
The apparatus 20 includes a plurality of elongated members 21 each with a longitudinally extending slot 22. Associated with each slot 22 is a relatively narrow roller 23 that projects inwardly of its associated slot 22.
The strip 19/18 passes along a predetermined path through the apparatus 20. The slots 22 and form folds 18 extend parallel to the longitudinal direction of extension of the strip 17/19 and therefore generally parallel to the path along which the strip 17/19 passes.
As the strip 19 approaches the slots 22 it is deflected into the slots 22 by the rollers 23. More particularly rollers 23 rotate about a generally horizontal axis 24 that extends generally normal to the strip 17/19 and slots 22.
After exiting the slots 22 the strip 17 passes over heating blocks 25. The heating blocks 25 have longitudinally extending slots 26, each slot 26 being aligned with a respective one of the slots 22 so as to receive a respective fold 18. As the strip 17 passes through the blocks 25, the folds 18 are heated to a desired temperature. Upon leaving the heating blocks 25 each fold 18 is engaged by a pair of rollers 27 so that each fold 18 is compressed therebetween so that the plastics material fuses (welds) to thereby ensure that each fold 18 retains its configuration. The rollers 27 rotate about generally vertical axis 28. The axis 28 are generally normal to the strip 17.
As is best seen in
In this embodiment there are four slots 22 and four associated rollers 23 and four heating blocks 25 each having a slot 26.
In the embodiment of
As best seen in the accompanying drawings (particularly
As best seen in
In another embodiment one or more opposing pairs of heated rollers 34 are located in the block 25. The folds 18 pass between the rollers 34 of each opposing pairs 34 to weld the folds 18 so that the folds 18 maintain their configuration.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2003900986 | Mar 2003 | AU | national |
