GB2121755A

GB2121755A - Apparatus for filling bags

Info

Publication number: GB2121755A
Application number: GB08314408A
Authority: GB
Inventors: Fritz Achelpohl; Konrad Tetenborg; Horst Schmidt
Original assignee: Windmoeller and Hoelscher KG
Current assignee: Windmoeller and Hoelscher KG
Priority date: 1982-06-07
Filing date: 1983-05-25
Publication date: 1984-01-04
Also published as: DE3221436A1; DE3221436C2; FR2533886B1; FR2533886A1; GB8314408D0; GB2121755B

Abstract

In a filling apparatus for bags which include an outer bag slit at the top to provide suspension loops and an inner plastics lining bag, the lining bag is clamped to a filling hopper connection 18 by spring levers (27) actuated by a movable ring (30) and the outer bag is suspended on elements (25, 26) mounted on pivotal arms which can be lowered to allow the bag to descend onto a conveyor during filling. <IMAGE>

Description

SPECIFICATION Apparatus for filling bags The present invention concerns an apparatus for filling bags, comprising a supporting outer bag which is provided with side folds and head and bottom seams and which at its filling end is provided with slits or cuts which open the inner fold edges of the side folds, and a cut which is parallel to said slits or cuts and which extends centrally through the side walls and through the head seam, and further comprising an upwardly open inner bag which is disposed in the outer bag and which is provided with side folds, the inner bag comprising plastics film, having a filling hopper which is arranged in a supporting frame structure, clamping means for clamping the bags and a conveyor for supporting the filled bags and carrying them away.

For reasons of economy, increasingly larger bags are used for packing goods which are in dust form or which are capable of flow, such bags comprising an impervious inner bag of plastics film or foil and a supporting or load-carrying outer bag, which preferably comprises a woven material of stretched plastics strips.

DE-OS No. 28 50 668 discloses an apparatus for filling large bags, wherein the bag is clamped to a bag holding means below the filling hopper, the bag, during the filling operation, is set down on a support means which is in the form of a force detector means or pick-up of a weighing machine, and the bag holding means is lowered, before the filling operation is completed, to such an extent that the wall of the bag is relieved of stress in the region of the filling operation opening. However, when filling large bags, because of the considerable weight thereof, a particular problem is involved in securely clamping them to a filling connection or nozzle. In addition, because of their weight, large bags must be of such a nature that, after they have been filled, they can be easily conveyed by conveyor means, as far as possible without accessory equipment.

A large bag which is easy to transport comprises a supporting outer bag which is provided with side folds and head and bottom seams and which at its filling end is provided with slits or cuts which open the inner fold edges of the side fold, and a cut which is parallel to the slits or cuts and which is taken centrally through the head seam and the side walls, and an upwardly open bag of plastics film orfoil which is disposed in the outer bag and which is provided with side folds. In a bag of that kind, after the central cut in the outer bag has been pulled open, the inner bag can be filled and closed, whereupon the side folds which are opened by the slits or cuts in their upper region form two carrier strips with which the bag can be hung on hooks or carrier means.

The problem of the present invention is to provide an apparatus for filling the bags as described above, wherein the filling connection or nozzle is relieved of the load of the weight of the bag while nonetheless, after the bag has been completely stretched and after it is completely filled, the bag can be automatically set down on a support means or the like, relieving the load in the upper region of the bag.

According to this invention, in an apparatus of the kind set forth above, that problem is solved in that the filling pipe or the filling hopper connection is provided with arms for fixedly clamping the edges of the opening of the inner bags, said arms being pivotal relative to the filling pipe or the filling hopper connection and carrying clamping members, and that there are provided sickle-shaped grippers which move through the slots in the outer bags, formed in the side folds, and which are mounted pivotally on carrier members which are guided in the frame structure and which can be raised and lowered by pressure medium piston cylinder units which lower the bags during the filling operation until they are supported on the conveyor.The sickle-shaped grippers may be easily pivoted into and out of the carrier strip portions formed by the cut-open side folds of the outer bag, and carry the outer bag, being supported on the frame structure, so that the filling nozzle or connection for filling the inner bag is relieved of the weight of the bag.

Another embodiment of the invention provides that the carrier members which are arranged at opposite sides of the bag are respectively pivoted to two parallel links or pairs of parallel links which are disposed one above the other, with the other ends thereof being mounted pivotally in the frame structure, that the sickle- or hook-shaped grippers are mounted pivotally in opposite directions in the carrier members about mutually parallel axes, and that pressure medium piston cylinder units are provided for pivoting the parallel links or grippers.

In accordance with a development of the invention, for which independent protection is claimed, it is provided that the arms carrying the clamping members comprise levers which are mounted pivotally on a peripheral line of the filling pipe orthe filling hopper connection and which are pressed outwardly by a spring force and which, by displacement of a ring which is guided displaceably in the axial direction on the connection or the pipe and which embraces same, can be pressed against same.

By virtue of a clamping ring being pushed over the spread-out levers, the levers are easily pressed against the outer peripheral surface of the filling pipe or connection, at the same time, clamping the filling end of the inner bag.

An embodiment of the invention will be described in greater detail hereinafter with reference to the drawing in which: Figure 1 shows a diagrammatic side view of the apparatusforfilling bags, Figure 2 shows a front view of the apparatus shown in Figure 1, Figure 3 shows a view in the apparatus in section taken along line A-B in Figure 1,and Figure 4 shows a view in longitudinal section through the filling hopper connection or nozzle, with the clamping arms for clamping the opening of the bag.

The filling hopper of the apparatus for filling bags or sacks is arranged with its clamping and carrier means for the bag, on a frame-like structure 1, as shown in Figures 1 and 2. Two U-shaped parallel links 2 and 3 are mounted pivotally in the frame structure 1. The limbs of the U-shaped parallel links are fixedly connected to carrier plates 4 and 5 which in turn carry two U-shaped carrier members 6 and 7.

The limbs of the carrier members 6 and 7 have bores through which the ends of bent pivotal arms 8 and 9 are passed and secured against axial movement by fixing rings 10 and 11. A pressure fluid piston cylinder unit engages one of the bent pivotal arms, namely the pivotal arm 9, by way ofan interposed lever 12. The piston cylinder unit is pivotally secured by means of its cylinder to a plate 14 which in turn is fixedly connected to the carrier plate 5. The rotational movement applied to the pivotal arm 9 by the piston cylinder unit 13 is transmitted to the pivotal arm 8 by way of a coupling linkage 15 which is connected to the bent pivotal arm 9. Stripper members 16 and 17 are also fixedly connected to the carrier plates 4 and 5.

For the purposes of filling a large bag, having a load-supporting outer bag and an inner bag, the inner bag is first suspended to the outer connection 18 of the filling hopper, which surrounds the actual filling pipe 19 at a spacing therefrom. The clamping means for clamping the inner bag will be described in greater detail hereinafter with reference to Figure 4.

After the filling opening of the inner bag has been clamped, the outer bag is pulled up. By actuation of the piston cylinder unit 13, the pivotal arms 8 and 9 are swung in and the two loops formed by the two slits in the outer bag are manualiy hung on the arms so that they carry the outer bag. The wall of the outer bag, which can be seen in Figure 1, bears against two projections or pins 20 which are provided on the outer connection 18 on oppositely disposed sides thereof so that, in the region of the edge of its mouth opening, the outer bag is pulled slightly taut. In that position, the large bag which is in a suspended condition is at a small spacing from the belt roller track 21.Now, as soon as material is introduced into the large bag 22 from the filling pipe 19, the bag, as soon as the bottom thereof has been formed into shape by the material in the bag, moves down onto the rolling track 21 and the remainder of the filling operation is then performed. So that the bag can be set down as the filling operation progresses, the pressure fluid piston cylinder unit 23 which is connected to the lower parallel link 3 is provided with a pressure reducing valve. After the filling operation has been finally concluded, the piston rod of the piston cylinder unit 23 is extended so that there is no longer any tension in the outer bag. When that has been done, the piston cylinder unit 13 is actuated and the curved pivotal arms 8 and 9 are moved out of the two slits in the outer bag of the large bag.The means clamping the inner bag to the filling pipe 13 orto the outer connection 18 is also released. Then, the entire arrangement is moved back into the basic position shown in Figure 2, by means of the piston cylinder unit 23.

An additional gas pressure spring 24 is provided to ensure that the entire unit remains in that position, in case the pressure for the piston cylinder unit 23 should fail.

As the carrier plates 4, 5 which are pivotally connected to parallel links describe a circular path during their downward movement, the position of the semicircular grippers relative to the outer bag would vary, thereby giving rise to friction. In order to prevent that from happening, the semicircular grippers 25 and 26 are connected to the curved pivotal arms 8 and 9 by way of a pivot means 27' and 28' which are not shown in greater detail.

Figure 4 shows a view on an enlarged scale of the outer connection or nozzle 18 and the innerfilling pipe 19. It will be seen from the drawing that a plurality of outwardly directed sprung levers 27 are arranged at the periphery of the outer connection 18, more specifically, in the lower region thereof. The inner bag 28 is pushed onto the outer connection 18.

Then, by means of the piston cylinder unit 19, the cylinder of which is externally secured to the connection 18, a ring 30 which is disposed around the outer connection 18 at a small spacing therefrom is moved downwardly and, during its movement, presses the clamping levers 27 from the outside against the outer connection 18 whereby the inner bag 28 is pressed firmly against the outer connection 18 and held in that position.

In order to facilitate fitting the inner bag 28 onto the connection 18, intersecting wire loop members 31 and 32 are joined to the lower end of the outer connection 18. For the purposed of guiding the ring for pressing the clamping levers against the connection 18, the ring has upwardly projecting guide pins 33 which are mounted in guide bushes 34 secured to the connection 18.

As can be seen from Figure 1, the outer connection 18 has an opening 35 to which a conduit 36 is connected. The conduit 36 can be selectively connected to a suction blower 37 or a pressure blower 38. The suction blower 37 is used for sucking away dust, while the pressure blower 38 is used for blowing up the inner bag which is supended from the connection 18.

Claims

1. Apparatusforfilling bags, comprising a supporting outer bag which is provided with side folds and head and bottom seams and which at its filling end is provided with slits or cuts which open the inner fold edges of the side folds, and a cut which is parallel to said slits or cuts and which extends centrally through the side walls and through the head seam, and further comprising an upwardly open inner bag which is disposed in the outer bag and which is provided with side folds, the inner bag comprising plastics film, having a filling hopper which is arranged in a supporting frame structure, clamping means for clamping the bags and a conveyor for supporting the filled bags and carrying them away, characterised in that the filling pipe (19) or the filling hopper connection (18) which is disposed therearound at a spacing therefrom are provided with arms (27) for clamping the edges of the opening of the inner bags (28), the arms being pivotal with respect to the filling pipe or the filling hopper connection and carrying clamping members, and that there are provided sickle-shaped grippers (25, 26) which pass through slits in the outer bags, formed in the side folds, and which are mounted pivotally on carrier members (4, 5) which are guided in the frame structure (1) and which can be raised and lowered by pressure medium piston cylinder units (23), which piston cylinder units lower the bags during the filling operation until they are supported on the conveyor (21).

2. Apparatus according to claim 1 characterised in that the carriers members (4,5) which are arranged at oppositely disposed sides of the bag are each pivoted to two parallel links or pairs of parallel links (2,3) which are arranged one above the other and the other ends of which are mounted pivotally in the frame structure (1), that the hook-shaped grippers (25, 26) are mounted pivotally in opposite directions in the carrier members about mutually parallel axes, and that pressure medium piston cylinder units (13) are provided for pivoting the parallel links (2,3).

3. Apparatus according to claim 1 or claim 2 characterised in that the grippers (25, 26) are secured to shafts (8,9) of which one carries a lever (12) to which there is pivoted one end of the pressure medium piston cylinder unit (13) which is mounted pivotally by its other end on the carrier member (5, 14), and that the shafts (8,9) are provided with levers (15) which are pivotally connected to a coupling linkage (15'), for their pivotal movement in opposite directions.

4. Apparatus according to one of claims 1 to 3 characterised in that the grippers comprise arcuately curved rods or bars which are secured to levers and which are arranged concentrically with respect to the pivot axis thereof.

5. Apparatus according to one of claims 1 to 4 characterised in that the grippers (25,26) are connected to the shafts (8,9) by pivot means (27,28) having a substantially vertical pivot axis.

6. Apparatus according to one of claims 1 to 4 characterised in that pins (20) which laterally engage the outer bag and which stress the upper region thereof are each arranged at a position at 90 relative to the grippers (25,26), on the filling pipe or filling hopper connection (18), below the gripping line of the grippers.

7. Apparatus according to one of claims 1 to 6 characterised in that there are provided springs (24) for urging the parallel links (2, 3) towards their upper position.

8. Apparatus according to one of claims 1 to 7 characterised in that, for the purposes of lowering the bags as they are filled, the pressure medium piston cylinder unit (23) for pivoting the parallel links (2, 3) is provided with pressure reducing valves.

9. Apparatus according to claim 1, characterised in that the arms (27) carrying the clamping members comprise levers which are mounted pivotally on a peripheral line ofthefilling pipe orfilling hopper connection (18) and which are urged outwardly by spring force and which, by displacement of a ring (30) which is guided displaceably in the axial direction on the connection or pipe and which embraces same, can be pressed against same.

10. Apparatus according to claim 9 characterised in that the ring (30) is provided with rods or bars (33) which are parallel to the generatrix thereof and which are guided in guide members (34) which are secured on the connection or pipe and which are provided with bores.

11. Apparatus according to claim 9 or 10 characterised in that a pressure medium piston cylinder unit (29) is provided for displacing the ring.

12. Apparatusforfilling bags constructed and arranged substantially as hereinbefore described and shown in the accompanying drawings.