The present invention refers to a method and to a device for producing rectangular-bottom bags.
In the field of production of bags for containing different kinds of objects, also rectangular or square-bottom bags are required, which are, indeed, quite difficult to produce.
It is indeed the rectangular or square-shaped base that makes the production particularly slow, since, to this day, a method for an automated manufacture has not yet been devised.
The purpose of the present invention is that of making the production of this type of bag as simple as possible.
Another purpose of the present invention is that of providing a method and a device which allow the aforementioned type of bag to be made faster.
These and other purposes according to the present invention are reached by making a method and a device for producing rectangular-bottom bags as outlined in the independent claims.
Further characteristics of the method are object of the dependent claims.
The characteristics and the advantages of a method and of a device for producing rectangular-bottom bags according to the present invention shall become clearer from the following description given as an example and not for limiting purposes, referring to the attached schematic drawings, in which:
With reference to the various figures, a method for producing rectangular or square-bottom bags, according to the present invention, is shown.
According to the present invention, it has been found that for making rectangular or square-bottomed bags it is necessary to start from a flat bag 10 with bottom bellows 11, as shown in
This bag 10 is made with predetermined width X and height Y dimensions according to the final rectangular-bottomed bag that is wished to be obtained. In particular, according to the method of the present invention the width dimension of the base X is equal to the sum of the width B and the thickness A of a finished and open rectangular-bottomed bag 20, as illustrated in
The initial flat bag 10 thus made is arranged on a supply plane 12 to be housed onto a forming group, schematically shown with 13 in
The forming group 13 comprises a pair of flat plates 15a and 15b, a pair of side shaping plates for bellows 16a e 16b and a wedge 17 for shaping the base of the bag. The two flat plates 15a and 15b are placed overlapping each other and have a width dimension Z equal to the width B of the finished rectangular-bottomed bag 20 of
Continuing the production method according to the present invention,
Once the aforementioned positions have been reached by all of the components of the forming group, the closure of the plates 15a and 15b will be carried out whereas the plates 16a and 16b advance towards each other according to the arrows U in contact with the walls P of the outer sides penetrating inside them so as to form bellows just as the wedge 17 will be inserted in the back wall or base wall Q of the bag C (
This combined movement is thus necessary to ensure that the bag, once the plates 15a and 15b have been closed downwards or are pushed towards one another and the plates 16a and 16b and the wedge 17 are penetrated as far as they can go, forms inner folds or bellows, taking up its desired final shape.
As a further step, see
The bag is thus formed as it is shown in
This bag is made with predetermined width X and height Y dimensions according to the final rectangular-bottomed bag that is wished to be obtained. In particular, in this embodiment two triangular portions 21 are removed from the base corners relative to parts of the bottom bellows 11 through wire welding means (not shown). Consequently, the width dimension of the base X is equal to the sum of the width B and of two thicknesses A/2 of a finished and open rectangular-bottomed bag 120, as illustrated in
The initial flat bag 10 thus made therefore has as an additional initial step, that of being removed of the corners 21, before being arranged on the forming group 13 from which it undergoes the same forming steps as the bag previously described.
Finally, it should be clear, that the method and the device thus conceived can undergo numerous modifications and variants, all covered by the invention; moreover, all the details can be replaced by technically equivalent elements. In practice the materials used, as well as the sizes, can be any according to the technical requirements.
Number | Date | Country | Kind |
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MI2009A 001049 | Jun 2009 | IT | national |