Patent Application
20160001909
The present invention relates to a packaging machine and a method for filling gusseted open-mouth bags and to an open-mouth bag. Gusseted open-mouth bags are either fed to this packaging machine prefabricated or else the bags are manufactured in the packaging machine itself or else in a device disposed upstream of, or assigned to, the packaging machine. For manufacturing the open-mouth bags, in particular tubular material is rolled off a roll of tubing and a section of tubular material of a predetermined length is cut off and provided with a bottom seam prior to filling the open-mouth bag through the filling end on top which is still open. After the filling process the filling end is sealed shut. Packaging machines which form the open-mouth bag in the machine itself and thereafter close it, are also referred to as Form-Fill-Seal machines (FFS machines).
The tubular material employed tends to be plastic tubular sheets. Its advantage is good water tightness.
The drawback of these known open-mouth bags is that the open-mouth bags may tear or burst open due to contact with pointed objects. Apart from loss of filled product, there may be considerable dust contamination to the environment which may even involve health risk to persons.
This is why open-mouth bags have been disclosed showing increased rupture strength to prevent the bag walls from tearing. These walls consist for example of tissue material of interwoven, frequently stretched, film strips. These tissue bags are also called ribbon tissue bags. The film strips may consist of materials such as HDPE, LDPE, or PP (polypropylene) which show comparatively high strength.
To render the tissue dustproof and optionally waterproof and even airtight, the tissue may be provided with coating on the inside and/or outside prior to manufacturing the tubular sheets, since absent coating it is not possible to ensure dustproof or airtight sealing at each single tissue mesh.
Sealing open-mouth bags from ribbon tissue of HDPE or PP is considerably more difficult when the filling mouth is to be closed.
Gusseted open-mouth bags of tubular sheet tend to be provided with corner welds for improved stacking capabilities to allow a square shape for the filled open-mouth bag. When sealing the open filling end on the top of an open-mouth bag of polyethylene film, not only the two film layers placed on top of one another in the central region of the open-mouth bag are welded to one another but so are the layers, 4 each, lying on top of one another in the region of the gussets. In this way, convenient grips or grasping recesses are generated at the ends of the closed open-mouth bag to comfortably take up and carry the filled open-mouth bag.
In the case of ribbon tissue bags of HDPE or PP, sealing the filling end is more of a challenge since the HDPE or PP material shows poorer weldability. As a rule therefore, in the case of open-mouth bags of ribbon tissue, only the inner layers consisting of polyethylene tend to be welded to one another. Since the inner, weldable PE layer is firmly joined with the ribbon tissue, this sealing also results in a tight sealing of the bag. The drawback of this is that only the front and rear gusset layers are interconnected in the outer gusset regions but not all of the 4 gusset layers are. Only the two layers whose inner films of polyethylene or the like lie on top of one another are connected with each other. Although this welding provides tight sealing for the bag, there are no convenient grasping recesses to comfortably carry the bag. Moreover the shape of the bag is optically less than optimal with the gussets gaping open. This is considered annoying in particular in the consumer goods market.
One possible solution for providing grasping recesses is to increase the welding temperature so that not only the inner layers of the open-mouth ribbon tissue bags are connected with one another but that the ribbon tissue layers fuse with one another. The drawback of this solution is that these weld seams are hard and brittle. In the case of shock-like loads the weld seams may tear open and product may thus escape.
Moreover many packaging machines are provided to process different bag materials adapted to current requirements and to alternate between processing e.g. PE film and ribbon tissue.
It is therefore the object of the present invention to provide a packaging machine for filling products into gusseted open-mouth bags and a method with which to provide grasping means for different materials, in particular also providing an attractive appearance. Furthermore it is the object to provide a suitable bag.
This object is solved by a packaging machine having the features of claim 1, by a method having the features of claim 11, and by an open-mouth bag having the features of claim 14. Advantageous more specific embodiments are the subjects of the subclaims. Further advantages and features can be taken from the description of the exemplary embodiments.
A packaging machine according to the invention serves for filling product and in particular for filling bulk goods into gusseted, open-mouth bags. The packaging machine comprises at least one filling device for filling the open-mouth bags through one filling end. At least one closing device is provided with which the filling end can be sealed at least substantially completely tight after the filling process by means of at least one weld seam in the transverse direction. At least one additional welding device is provided. The additional welding device is suitable and configured to place in the gussets of the open-mouth bags two additional holding seam spaced apart from one another in the transverse direction. These additional holding seams serve in particular to provide a grip or grasping means for holding the filled open-mouth bags. Moreover the appearance is enhanced.
The additional holding seams are placed approximately parallel to the weld seam. The additional weld seam is preferably disposed and configured so that the additional holding seams are placed approximately parallel or parallel to the weld seam. The additional welding device and the closing device closing the filling end are in particular disposed approximately parallel or parallel to one another. An angle between the weld seam and the additional holding seam is preferably less than 20° and in particular less than 10° and particularly preferably less than 5°. The additional holding seam is oriented transverse to a longitudinal edge of the open-mouth bag and is preferably oriented approximately perpendicular to the longitudinal edge of the open-mouth bag. An additional holding seam extends transverse to a longitudinal edge of the open-mouth bag and does not intersect the weld seam.
The packaging machine according to the invention has many advantages. The packaging machine according to the invention is very versatile and can be used for a great variety of bag materials.
A selection device for selecting a bag material is preferably provided. Then the additional welding device can be activated in dependence on the bag material selected. When a bag material does not require the additional welding device, selecting the respective bag material deactivates the additional welding device.
Thus, the selection device may for example select a conventional, for example polyethylene film, bag material so as to enable conventional processing. However, if the selection device selects another bag material showing somewhat poorer welding properties, then the additional welding device is activated so as to place additional holding seams in the open-mouth bag gussets prior to or after sealing the filling end of the open-mouth bag. Since the closing device already seals the open-mouth bag by a weld seam to be entirely tight, the holding seams may fulfill the function of a grasping means. When placing the holding seams it is not necessary to provide not too brittle holding seams. Since the holding seams are as a rule subjected to static loads namely, as the user takes the filled open-mouth bag by the ends for example to transfer it to the shopping cart or to transport it to the place of application, there are as a rule no dynamic loads on the holding seams. It is dynamic loads which are critical in particular on brittle joints. Filled product is prevented from escaping from the interior of the open-mouth bag by the weld seam of the closing device, which may be configured for dynamic loads as well.
The packaging machine is in particular intended for bagging bulk goods. The packaging machine preferably comprises a machine frame which may be designated as the sum total of all the load-bearing components of the packaging machine. The machine frame tends to have attached to it metal sheets or sheet-type materials constituting a housing to enclose the packaging machine versus the exterior. The machine frame may fulfill the function of a housing.
In all the configurations it is particularly preferred for the filling device to be suitable and configured to fill open-mouth bags in one filling process, the open-mouth bags comprising a bag body having two ends enclosed by a bag wall which bag body extends over a length between the two ends and has a width transverse thereto, and where one of the ends is the bottom end and the other of the ends is the filling end, and where a central section of the bag body is provided with a front and a rear bag wall, while the gussets are provided with two front and two rear bag walls each.
The two front bag walls are in particular joined in the side regions at the gussets by way of a front corner weld seam and the two rear bag walls are joined by a rear corner weld seam to enable a square shape of the filling end of the bag body after the filling process. The corner weld seams extend at an angle to the longitudinal edge of the open-mouth bag in particular from a longitudinal edge to a side edge.
In all the configurations it is preferred to provide a control device for controlling. Preferably the additional welding device is configured to generate a welding temperature that is at least 40 Kelvin higher in the region of the gussets than that at the welding device for welding the filling end in the region of the gussets. It must be taken into account that in the region of the gussets the closing device also generates a welding temperature that is preferably at least 40 Kelvin higher than in a central section of the open-mouth bag since in the region of the gussets, four layers are welded to one another and therefore more energy is required. This means that the additional welding device generates a welding temperature that is in particular at least 60 Kelvin and preferably at least 80 Kelvin higher than the closing device generates in the central section of the open-mouth bag.
The high welding temperature for generating the holding seams ensures that not only the surface layers of the bag material are fused on but for example inserted tissue layers if any are fused on as well.
Preferably the additional welding device comprises two laterally spaced apart welding jaws and/or welding jaws. The welding jaws are configured separately, each generating a holding seam in the open-mouth bag gussets.
The welding jaws of the additional welding device show varying cross sections and/or coatings over their width to generate different temperatures over the width of the welding jaws. The welding jaws extend transverse to the longitudinal direction of the open-mouth bag over at least part of the depth of the gussets. The welding jaws of the additional welding device comprise in particular a width that is less than the depth of the gussets of the open-mouth bags intended for filling. This means that as a rule the holding seams do not extend over the entire depth of the gussets. This allows to ensure that even if the open-mouth bags are slightly displaced laterally the holding seams are welded only in the region of the gussets.
Preferably the welding jaws are designed such that the welding temperature generated in the sections lying outwardly is lower than it is in at least one section lying further inwardly. This is to ensure that in the outwardly sections the holding seam is less brittle than further inwardly. This provides an elastic region of the holding seam so as to considerably reduce the risk of the holding seam tearing open starting from the side edge of the open-mouth bag. Thus the holding seam, which may be brittle, can better withstand even dynamic loads and stresses e.g. in the initial moments of pulling when being gripped.
It is also possible for the additional welding device to comprise at least over the bag width a continuous welding strip which in the region of the gussets shows a higher electric resistance than it does in a central section between the gussets. The electric resistance of the welding strip across the depth of the gussets is preferably higher in an outer section than in an inner section. The welding strip is in particular configured such that in a central section between the gussets no weld seam or just a weak weld seam is generated while in the regions of the gussets a considerably stronger weld seam is generated which joins all of the gusset layers together. The fact that the electric resistance of the welding strip is lower in an outer section of the holding seam provides for enhanced elasticity of the edge of the holding seam.
The electric resistance of the welding strip or also of the welding jaws may be adjusted by means of different cross sections and/or different coatings. For example coatings of different materials and in different thicknesses may be applied to accordingly influence the resistance of the welding jaw or of the welding strip. A lower resistance causes the local welding temperature to decrease so that the weld seam may be influenced accordingly. The welding temperature in the outer section is in particular more than 20 Kelvin and in particular more than 40 Kelvin lower than in the inner section of the holding seam. The welding temperature within the holding seam lies in a range in which ribbon tissue can be fused on.
The welding jaws and the welding strip respectively may be heated periodically or continuously. The welding jaw may be configured as a welding block.
Preferably at least one corner welding device is provided which is suitable and configured to place corner weld seams in the gussets at least at the filling end. For the corner weld seams only two gusset layers are joined to one another.
Preferably a bag former is provided which is suitable and configured for manufacturing and separating open-mouth bags from a tubular sheet.
The method according to the invention serves for filling products and in particular bulk goods into gusseted open-mouth bags, the open-mouth bags being filled by means of a filling device through a filling end. After the filling process the filling end is sealed at least substantially entirely tight by means of a weld seam in the transverse direction. An additional welding device inserts in the gussets of the open-mouth bags at least two additional holding seams which are laterally spaced apart in the transverse direction and oriented approximately parallel to the weld seam.
The method according to the invention has many advantages since it provides grasping means for holding the filled open-mouth bag by the holding seams placed in the gussets. The optical appearance of the finished, filled open-mouth bags is also enhanced.
In all the configurations it is particularly preferred for the elasticity of the additional holding seams to increase outwardly. In this way the holding seam shows higher elasticity where the fingers or the hand of a user grasp the filled open-mouth bag, and thus it shows higher load resistance also to dynamic loads so that the holding seam is prevented from tearing. However, even if the holding seam should tear, the filled open-mouth bag remains closed as a rule.
Preferably a selection device may be used for selecting the bag material. The additional welding device is activated in dependence on the bag material selected. The additional welding device may be activated or deactivated by way of the selection device so as to allow processing a great variety of gusseted bag types.
The open-mouth bag according to the invention comprises a bag body having two ends with the bag body extending over a length between the two ends and having a width transverse thereto. The bag body is enclosed by a bag wall. One of the ends is the bottom end or the bag bottom and the other end is the filling end. At least the filling end of the bag body is provided with gussets in side regions in the bag wall so that the filling end of the bag body is provided with front and rear bag walls in a central section of the bag body while the gussets in the side regions are provided with two each of front and rear bag walls. The bottom end is at least substantially closed and the filling end is at least substantially completely closed over the entire width by at least one weld seam in the transverse direction. At least the filling end is provided at least in the side regions in the gussets with at least one additional holding seam in the transverse direction oriented approximately parallel to the weld seam with which all of the two front bag walls and the two rear bag walls are connected.
The open-mouth bag according to the invention has many advantages since other than reliable function it also provides convenient holding seams. This holding seam is in particular configured as a weld seam and it may also be referred to as a welded holding seam. The holding seams provide a convenient grip or gripping recess for the fingers to hold the bag body.
Preferably the two front bag walls are connected with one another in the side regions by way of a front weld seam, and the two rear bag walls are connected with one another by way of a rear corner weld seam to enable a square shape of the filling end of the bag body.
Particularly preferably the two ends of the open-mouth bag are each provided with a corner weld seam so as to achieve a square shape of the entire filled open-mouth bag.
Preferably the two ends are each provided with at least one additional holding seam in each of the two side regions of the gussets. Particularly preferably a total of four holding seams is provided namely, one at each of the four corners of the filled open-mouth bag. Every holding seam is in particular configured as a weld seam.
The additional holding seams preferably comprise in the transverse direction of the bag body at least two seam sections of different intensity. This means that every holding seam comprises at least two seam sections of different intensities and/or elasticities. Preferably the additional holding seam shows higher elasticity toward the side edge of the bag body. This can be realized by generating the seam section intended to be closer to the side edge of the bag body at a lower welding temperature than the seam section of the additional holding seam provided farther to the rear.
In all the configurations it is preferred for the additional holding seam to be provided closer to the filling end than is the weld seam for closing the filling end. The advantage of this is that the additional holding seam is provided in a region blocked off from the filled product. Then the filled product cannot escape even if the holding seam should tear.
It is also possible and preferred to provide the additional weld seam for closing the filling end, closer to the filling end than the holding seam. This is possible in particular if the additional weld seam is located within the region blocked off by the corner weld seam and does not intersect the corner weld seam. Then even if the holding seam, which may be brittle, should tear, any product filled in the open-mouth bag cannot escape outwardly. The region of the holding seam is blocked off from the bag interior by way of the corner weld seam.
In a preferred embodiment the bag wall of the bag body consists in an outer layer, e.g. of ribbon tissue, and at least one coating layer joined thereto. The coating layer is disposed on the interior of the bag body. Preferably the coating layers of the front and rear bag walls are welded to one another by the weld seam for closing the filling mouth. In particular only the coating layers of the front and rear bag walls are welded to one another in this place.
The ribbon tissue of each of the two front and the two rear bag walls are fused with one another by the additional holding seam at least to a considerable part to form a joint weld seam. This means that not only the coating layers are welded to one another but so is a considerable part of the ribbon tissue layers of all the bag walls lying on top of one another to provide an additional holding seam joining all the layers. The joint weld seam is preferably only provided in the region of the gussets.
Further advantages and features of the present invention can be taken from the exemplary embodiments which will be described below with reference to the enclosed figures.
The figures show in:
The packaging machine 30 illustrated in
The packaging machine 30 is configured as an FFS packaging machine and comprises a film reservoir 31 with at least one roll of tubing. The film reservoir 31 contains rolled up tubular sheet 32 that serves for manufacturing the bags 1. Open-mouth bags 1 can be manufactured as needed by providing a film reservoir 31 containing one or more rolls of tubing. The length of the bags is in particular variably adaptable and it can readily be adapted to the currently desired filled quantity.
The tubular sheet 32 that was unwound from the film roll of the film reservoir 31 is conveyed through the film store 33 to the interior of the packaging machine 30 and is conveyed to the corner welding device 34. The corner welding device 34 can place corner welds as needed which are shown as corner weld seams 29a for example in FIG. 4. These corner weld seams or corner welds 29a give the filled open-mouth bag 1 its square shape so that the bag is readily stackable in an optically appealing way.
After optionally manufacturing the corner weld seams 29a, 29b the tubular sheet 32 with the corner weld seams in the gussets 20 proceeds to the bag length equalizer 36 which serves to synchronize the clocked operation of the packaging machine 30. The bag length equalizer 36 allows to evenly, continuously unwind the film roll of the film reservoir 31 while allowing clocked operation for manufacturing the open-mouth bags 1 and for filling and subsequently closing the open-mouth bags 1 in the interior of the packaging machine.
The film drive 37 serves to transport the tubular sheet 32 and it may concurrently capture travel data so that the control device 57 of the packaging machine 30 is at all times provided with information about the position of each of the tube lengths relative to the film roll.
Thereafter the tubular sheet 32 is fed to the closing device 42 where first the tubular sheet is clamped by means of the clamping mechanism 35 before (see
The selection device 58 serves to select the bag material 12. The additional welding device 59 is activated or deactivated in dependence on the selection. Or else, automatic identification of the bag material 12 or external signal transmission may be provided.
Thereafter the weld seam 5 at the bag bottom 3 may be cooled by means of a cooling device 43 to obtain sufficient stability while providing for high throughput.
A shuttle transporter 45 conveys the bag 1 further by means of the pivotal swing arms and a bag opener 40 opens it. In the next clock cycle the bag 1 is appended by the filling mouth 11 to the filling device 53 respectively its filling spout 53 and is filled with product 8 out of the product feeder 54. Filling may be performed by way of a net process where a certain quantity of product is weighed before it is fed to the open-mouth bag. Other filling methods are likewise conceivable.
After the filling process the open-mouth bag 1 is conveyed via the shuttle transporter 45 to the closing device 55 which in turn is provided with a clamping mechanism 35 and welding jaws 38.
At the closing device 55 the filling end or second end 4 of the open-mouth bag 1 is closed by way of a weld seam 5 respectively a top seam 41. The weld seam 5 in turn extends in the transverse direction 24 preferably over the entire width 7 of the bag 1 and at least over the width of the filling mouth, enabling tight sealing of the bag interior.
The closing device 55 illustrated in
Above the welding jaws 38 the additional welding device 59 is provided comprising welding jaws 60 and 61. In the view according to
The welding jaws 60 and 61 are spaced apart from one another in the transverse direction 24 of the open-mouth bag 1 so that both the welding jaws 60 and the welding jaws 61 are provided in the regions 25 of the gussets 20 (see
The welding jaws 38 of the closing device 55 serve to seal the open-mouth bag 1 tight while the welding jaws 60 and 61 of the additional welding devices 59 serve to provide the bag ends with holding seams 22 and 23 which provide a grip 15 and grasping means at the bag ends. The closing device 42 is analogous in structure.
While the welding jaw 38 for closing the filling end 4 of the open-mouth bag 1 extends over more than the width 7 of the open-mouth bag 1, the welding jaws 60 and 61 are both provided within the respective regions 25 of the gussets 20. The welding jaws 60 and 61 each show the same width 62 and they are divided over their width 62 in different welding sections 66 and 67 and optionally 68. While outer sections 66 are provided toward the outer edge, sections 67 are disposed further inwardly. The welding temperature obtained in the sections 67 is markedly higher than in the outer sections 66. It is possible to subdivide the outer sections 66 further in sub-sections as is indicated in
The outer section 66 shows the substantial difference from the further inwardly section 67 that the welding temperature is considerably reduced in the outer section 66. While the welding temperature provided in section 67 is particularly high so as to result in fusing all the four layers of the bag wall, the welding temperature in the outer sections 66 is considerably reduced. This results in enhanced elasticity of the weld seam at the outer end of the holding seams 22 and 23. The enhanced elasticity of the holding seams 22 and 23 at the outer edge provides the grip 15 with strength for dynamic loads also. The risk of tearing starting from the outer edge is effectively reduced. In analogy the welding temperature in the optional section 68 may be provided lower as well.
In this exemplary embodiment according to
The bag body 8 comprises a longitudinal face 28 and a transverse face and is enclosed by a front bag wall 2a and a rear bag wall 2b (not visible in
In the exemplary embodiment according to
The open-mouth bag 1 according to
On the whole the invention provides an advantageous packaging machine 30 which, e.g. by way of a selection device 58, can select the bag material 12 for the open-mouth bags 1 to be filled. In dependence on the selected bag material, an additional welding device 59 is activated which for example when filling product 8 into open-mouth bags of ribbon tissue 14 provides for manufacturing grips 15 or grasping means at the corners of the filled open-mouth bags 1 so as to allow convenient transport and also provide an attractive appearance since the corners do not protrude from the bag body 9.
If the bag material 12 processed does not require the additional welding device 59, it may be deactivated.
It is also possible to have the bag material 12 detected automatically and in dependence on the material detected the additional welding device may be activated or deactivated, if the weld seam 5 already ensures interconnection of all the four layers in the regions 25.
On the whole the invention provides an advantageous packaging machine and an advantageous method for filling product into open-mouth bags, and an advantageous open-mouth bag.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2013 003 223.7 | Feb 2013 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2014/053775 | 2/26/2014 | WO | 00 |
