Bag-processing Machine

Abstract

A bag-processing machine comprises a first arrangement for advancing bags in a predetermined path at a first speed past a first operating station. A second arrangement is spaced in direction downstream from the first arrangement and serves to advance the bags in the same path but at a higher second speed past a second operating station. Transfer means is arranged intermediate the first and second arrangements and receives the bags from the first arrangement at the first speed, engages them by suction and transfers them to the second arrangement at the aforementioned second speed.

Description

BACKGROUND OF THE INVENTION

The present invention relates generally to the processing of bags, and more particularly to an apparatus for processing of bags.

Apparatus is known which forms bags at a first operating station from suitable material and advances these bags in form of a chain of connected bags in a predetermined path. A cutting device severs the respectively leading bag from the chain, and the thus-severed leading bag is then advanced to another operating station for further processing, for instance for filling and closing, or for other purposes. Usually, the bags must advance past the second processing station at a speed greater than that at which they advance past the first processing station and are supplied by the cutting device for transfer to the second processing station. A transfer device is provided for this purpose which engages the bags at the first speed as they are supplied by the cutting device, and accelerates them to supply them at the higher second speed to the second operating station. Known transfer arrangements used for this purpose engage the severed leading bags between pairs of rollers and accelerate them prior to releasing them to the arrangement which serves to advance them to and past the second operating station. These arrangements have the disadvantage, however, that if the bags are to be supplied in proper predetermined relationship to the arrangement which advances them to the second operating station--as they must be in order to be in proper position for the further processing which they are to undergo--then the pressure with which the rollers of the respective pairs engage the bags in the transfer device must be precisely adjusted. Accordingly, if different materials are used, that is when the device has been adjusted for bags of one material and is now to be used with bags of another material, or if the surface consistency of the bag material differs, a readjustment of the pressure exerted by the rollers is necessary in every instance. This is evidently both time-consuming and demands a certain amount of skill so that special personnel must be available for carrying out these adjustments.

SUMMARY OF THE INVENTION

It is, accordingly, an object of the present invention to provide an apparatus for bag-processing purposes which is not possessed of the aforementioned disadvantages.

More particularly it is an object of the present invention to provide such an apparatus which requires no precise adjustment of the transfer means if the material or surface consistency of the material of the bags varies from batch to batch or from case to case.

A further object of the invention is to provide such an apparatus which is simple in its construction but highly reliable in its operation.

In pursuance of the above objects, and others which will become apparent hereafter, one feature of my invention resides, briefly stated, in a bag-processing machine which comprises first means for advancing bags in a predetermined path and at a first speed past a first operating station. Second means is spaced in direction downstream of the first means and serves to advance the bags in the aforementioned path but at a higher second speed past a second operating station. Finally, I provide transfer means arranged intermediate the first and second means and serving to receive the bags from the first means at the first speed, engaging them by suction, and transferring them to the second means at the aforementioned second speed.

By utilizing suction engagement for the bags I obtain various advantages which cannot be had with the apparatus according to the prior art. Among these is, of course, the fact that there is no need to provide for specific adjustments if the material of the bags varies, or if the surface consistency of the material differs. A further advantage of my novel apparatus resides in the fact that it permits me to interrupt in a most simple manner the supply of bags from the first means to the second means if this is necessary or desirable, for instance if the second means should become temporarily inoperative, or if it is desired to make spot checks at intervals of the bags being supplied by the first means, for instance to determine whether their seams are properly sealed if they are of synthetic plastic material, or for any other purpose. This is accomplished by momentarily interrupting suction whereby any bags supplied by the first means to the transfer means while the suction is interrupted, will simply fall off and can be collected for inspection or for any other purposes.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a simplified rather diagrammatic perspective view of an apparatus embodying the present invention, with components not essential for an understanding of the invention having been omitted; and

FIG. 2 is a detail view, on an enlarged scale, of the transfer means used in the apparatus of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Discussing now the drawing in detail, and firstly FIG. 1 thereof, it will be seen that reference numeral 1 identifies a supply roll from which a web 2 of material--such as, for instance, synthetic plastic material--is continuously withdrawn over an abutment 11. Downstream of the abutment 11 there is arranged a folding member 12, having a generally fork-shaped configuration, and the web 2 is drawn through the folding member 12 by the action of the withdrawing rollers 13, 14 and is thereby folded longitudinally in half into a generally V-shaped strip 3.

Intermediate the folding member 12 and the withdrawing rollers 13, 14 there is arranged a sealing device comprising the diagrammatically illustrated pairs of sealing jaws 15. Such sealing devices are known to those skilled in the art and form no part of the present invention. It is pointed out, however, that they are pressed in known manner against the V-shaped strip 3 and that they will usually advance with the strip 3 through a predetermined distance, to thereupon return to their starting position. In any case, the sealing jaws 15 serve to provide a plurality of sealed seams extending transversely of the elongation of the strip 3, thereby providing a chain 4 of connected individual bags, with the width of each bag corresponding to the distance between two adjacent pairs over the jaws 15. The open side of each of the bags 4 faces upwardly in FIG. 1.

Downstream of the withdrawing rollers 13, 14 there is arranged a severing device consisting in the diagrammatically illustrated embodiment of a stationary knife blade 16 and a rotary knife blade 17 (see also FIG. 2), with the rotation of the knife blade 17 being so selected that it severs the respectively leading bag 5 from the advancing chain 4 of connected bags.

The web 2, which is transformed into the chain 4 of bags, advances in direction towards the cutting or severing arrangement 16, 17 under the influence of the withdrawing rollers 13, 14 at a predetermined first speed.

Downstream of the severing device 16, 17 and spaced therefrom is a pair of cooperating endless belts 19, 20 mounted for rotation about pairs of rollers, as illustrated in FIGS. 1 and 2, and which advance in the direction indicated by their associated arrows at a second speed which is higher than the first speed imparted by the rollers 13, 14. The belts 19 and 20 are so arranged that they engage the bags 5 in the region of their open side, advancing them to a further advancing arrangement located downstream of the belts 19, 20 and comprising engagement members 21 which may be of known construction and which engage the bags 5 at their lateral edges below the upper open side of the bags. Now the bags 5 are advanced to a filling station 23 where they are filled with whatever contents they are to accommodate, and thereupon the filled bags are passed to a closing device 24 which closes their upper open ends. The arrangement and construction of the filling station and of the closing device form no part of the present invention and any suitable and well-known type may be utilized. They are illustrated in FIG. 1 only to clarify the further processing steps to which the bags are subjected once they have been released by the belts 19, 20.

As pointed out above, the severed bags 5 are supplied from the severing device 16, 17 at a first speed imparted to them by the advancing rollers 13, 14. The belts 19, 20 advance at a second speed which is higher than the first speed. In order for the severed bags 5 to be brought up to the higher speed so that they can be smoothly engaged by the belts 19, 20 a transfer device is necessary. This transfer device, identified with reference numeral 18 and shown on an enlarged scale in FIG. 2, comprises in accordance with my invention a suction chamber 25 having an open side whose general plane coincides with the general plane of the path in which the severed bags advance from the severing device 16, 17 to the belts 19, 20. A suction-producing device 27, such as a vacuum pump, is diagrammatically illustrated in FIG. 1 and communicates via suitable conduit means, and a valve 26, with the interior of the suction chamber 25. In accordance with my invention the suction chamber is surrounded by a movable wall overlying its open side and being apertured so that, when the bags 5 move onto this movable wall, they are held by suction against the same and are advanced by movement of the movable wall.

The particularly advantageous embodiment illustrated in FIGS. 1 and 2 shows the movable wall to consist of a plurality of endless belts or bands 28 which are trained about the rotary rollers 29, 30 and 31 all of which are arranged in axial parallelism with one another. In this embodiment the belts 28 actually are spaced from the wall of the suction chamber 25 and the rollers 29, 30 and 31--of which one, two or all may be driven in suitable manner by any drive means known to those skilled in the art--are rotated continuously in the direction of the arrows associated with them in FIG. 2.

It will be noticed that the belts 28 are spaced from one another axially of the rollers 29, 30 and 31 at predetermined distances which are advantageously constant and identical. The speed at which the belts 28 advance in the sense imparted to them by the rotation of the rollers 29, 30 and 31, is significantly higher than the speed at which the withdrawing rollers 13, 14 advance the web 2 and consequently the bags 5 which are produced from the web 2; it equals the speed of the belts 19 and 20 which in turn equals the speed of advancement of the engaging members 21.

It should be emphasized that in place of the belts 28 a one-piece belt or analogous wall-defining member could also be provided, formed with suitable apertures to permit for suction engagement of the bags 5. Such other possibilities, which also form a part of the invention and which are not to be considered excluded by the fact that I have illustrated a particularly advantageous arrangement, are of course a part of the invention.

Evidently, the severed bags 5 are engaged by suction by the transfer device 18. More specifically, the leading edge portion of each bag 5 slides onto the belts 28 or analogous wall-defining member before the trailing edge portion of the same bag is yet severed from the chain 4. Because the chain 4 is firmly engaged between the advancing rollers 13, 14 the fact that the leading edge portion of the leading as yet unsevered bag 5 overlies the belts 28 does not permit the chain 24 to be accelerated to the speed of the transfer device 18. This acceleration takes place only after the trailing edge of the leading bag 5 is severed from the chain 4, whereupon the bag 5, whose leading edge is already held by suction against the belts 28 which slide underneath it during their continued movement, can now be carried along by the belts 28 in direction towards the belts 19, 20.

In order to prevent flexing of the belts 28 and of the bags 5 carried along by the same in direction into the interior of the suction chamber 25, I provide supporting bars or the like 34 extending across the open side of the suction chamber 25 and each located behind one of the belts 28 in registry therewith. The bars or analogous elements 34 are of the same width or at least substantially the same width as the belts 28 and are secured in suitable manner so that the belts 28 slide over them; it is evident that direct physical content is not necessary and that the bars 34 may be slightly spaced from the belts 28.

A comblike abutment element 32 is located inwardly of the open side of the suction chamber 25 and provided with teeth or projections 33 which each register with a gap between two adjacent ones of the belts 28. The abutment member 32 can rotate about an axis defined by the shaft 32a so that its projections 33 can extend into the gaps between adjacent ones of the belts 28, and be withdrawn therefrom. When they are extending into these gaps, that is when they are in the position illustrated in FIG. 2, the projections 33 serve as abutments for the bags held by suction against the belts 28 and being advanced by the same in direction from the right towards the left-hand side of FIG. 2. Contact of the leading edge of the bags 5 with the projections 33 serves to align any bag 5 which may be skewed, so that it is in proper position for engagement by the belts 19, 20. Once such contact has taken place, the member 32 rotates about the axis defined by its shaft 32a in a sense withdrawing the projections 33 from the gaps between the belts 28 so that the bag 5 can continue towards the belts 19, 20 for engagement by the same.

Control of the rotation of the member 32 may be effected by suitable control means 35 which is already well known in the art and which in turn may be actuated in dependence upon the particular position of the engagement members 21 to which the bags 5 are supplied by the belts 19, 20. For this reason the control means 35 is actuated by the driving means 36 of the engagement members 21.

Not only does the apparatus herein disclosed and illustrated by way of an exemplary embodiment, provide the advantages which have been set forth in the introductory portion of this disclosure, and avoid the disadvantages of the prior art, but it has the additional feature of affording at all times a very clear unobstructed view of the accelerating or transfer device 18 so that the proper operation of this device may be ascertained at a quick glance. This is important because the device 18 is an important part of the apparatus of the type under discussion, especially because of the precision of cooperation between the various components of such apparatus which is necessary to assure flawless functioning.

It is again emphasized that such details as the control of rotation of the rotary knife 17, of the advancing rollers 13, 14, the rollers 29, 30 and 31, the operation of the vacuum pump 27 and the valve 26 and their construction, the operation and construction of the filling station 23 and the sealing station 24, the guidance and operation of the gripping members 21 are not essential for the purposes of the present invention. All of this can be accomplished with known apparatus in known manner which forms no part of the present invention.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.

While the invention has been illustrated and described as embodied in a bag-processing machine, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Claims

I claim:

1. In a bag-processing machine, in combination, first means for continuously advancing a coherent chain of bags in a predetermined path and at a first speed; severing means for severing the respectively leading bag from said coherent chain; second means spaced in direction downstream of said first means and said severing means for continuously advancing the severed bags at a higher second speed past an operating station; and transfer means intermediate said severing means and said second means for receiving severed bags from the former, engaging them by suction, and transferring them to said second means at least at said second speed, said transfer means comprising aperture-defining wall means surrounding an internal chamber and at least substantially bridging the space between said severing means and second means, said wall means travelling at least in part in direction from said severing means toward said second means, and suction means for creating suction in said chamber so that, when severed bags advance from said severing means onto said wall means, suction is exerted on them through said apertures and said bags are maintained in position during transfer to said second means.

2. In a machine as defined in claim 1, and further comprising abutment means on said transfer means and arranged for abutting engagement with the severed bags engaged by said transfer means for imparting to such engaged bags a predetermined orientation with reference to said path.

3. In a machine as defined in claim 2, said abutment means being arranged for movement alternately into abutting position transversely of the advancement of each engaged bag and thereupon into withdrawn position subsequent to abutment with the respective bag.

4. In a machine as defined in claim 2, wherein said wall means comprises first wall means defining said internal chamber with the latter having an open side, and travelling second wall means traveling past said open side in close proximity thereto and defining said apertures.

5. In a machine as defined in claim 4, wherein said second wall means comprises a plurality of endless belts each having a belt section overlying said open side and extending in direction from said first means towards said second means, said belt sections being spaced transversely of said direction and defining with one another elongated gap-shaped apertures.

6. In a machine as defined in claim 5, wherein said abutment means comprises an abutment element extending in a plane at least substantially parallel with the general plane of said belt sections and comprising a plurality of projections at least one of which extends into each of said apertures in response to movement of said abutment means from a withdrawn position to an operative abutting position.