EP0670799A1

EP0670799A1 - Process and device for automatically closing transport bags.

Info

Publication number: EP0670799A1
Application number: EP94926767A
Authority: EP
Inventors: Markus Nuetzi; Peter Naef
Original assignee: Buehler AG
Current assignee: Buehler AG
Priority date: 1993-10-04
Filing date: 1994-09-28
Publication date: 1995-09-13
Anticipated expiration: 2014-09-28
Also published as: DE59400381D1; DK0670799T3; CN1115176A; ES2089925T3; MY112107A; UA42705C2; CN1053418C; EP0670799B1; RU2118275C1; WO1995009765A1; JP2950994B2; US5890348A; JPH07509681A; TW276234B; BR9406466A; ATE139741T1; TR28106A

Abstract

A process and device are disclosed for automatically closing transport bags, in particular paper bags for flour, fodder and the like with more than 5 kg mass. The object of the invention is to allow such bags to be automatically closed at a speed of about 1200 bags per hour in a very flexible manner as far size and weight of the bags is concerned, with a relatively simple equipment. For that purpose, the filled bags are at first spread open and vertically aligned, then clamped and provided with a double fold. Glue is applied between the folding steps and the double fold with glue is pressed between compression rollers.

Description

Be honored

Method and device for the automatic closing of transport bags

The invention relates to a method for automatically closing transport bags after filling with a bulk material according to the preamble of claim 1, and to a device for carrying out the method.

The method according to the invention and the associated device are used in particular when bagging and closing transport bags (preferably paper bags) for large packagings (approx. 10-50 kg) of flours, animal feed and the like. like.

Small consumer packs of up to approx. 2 kg are usually sealed in high-performance packaging machines. Due to the small size of the masses and paper surfaces to be moved, the movement sequences can be carried out at high speed, which enables very high performance.

Large packagings with masses greater than 5 kg, however, require a completely different handling. The frequently used transport bags can have a mass of up to 50 kg and more. Even if there is a certain tendency towards smaller packagings, the masses to be moved, the unstable container type and the flat sack parts only allow comparatively low accelerations. Accelerations that are too high would damage the sack material or deform the container together with the opening in such a way that it becomes unusable for subsequent work steps.

In the case of so-called valve bags, the closing is relatively unproblematic owing to the filler opening which can be closed in the manner of a valve, but they are The empty bag price and sanitation are only used to a limited extent for food and feed.

Food and animal feed, in particular also ground materials, require a tight closure of the transposed bag in both directions. The filling material must neither emerge from the sack, nor must moisture, pollutants or insects penetrate it. The transport sacks must be carefully closed by sewing (holes, perforation) or better by gluing / gluing.

Likewise, even small differences in the density of the sack contents result in differences in the degree of filling. Since a transport sack does not have a precisely defined volume in the unlocked state, its automated handling and palletizing is problematic. Each sack outside is nevertheless shaped uniformly and must not include any air cushions in order to produce a transportable sack stack (palletizing). It is therefore not possible, for. B. only want to increase the degree of mechanization of a bag closing device. In addition, there are very different lot sizes, which require frequent changing of the facility.

This also shows the limits of widespread sewing. The speed of sewing cannot be increased at will, sacks made of thin material (weight reduction) cannot be sewn tightly and tend to tear. A basic way out is to glue / glue the bags.

In the case of a filled and unspread transport bag, the position of the edges of the bag opening can vary widely, which makes exact sewing or gluing difficult. It is Z. B. necessary and known to cut a strip from the upper edge of the bag for an exact folding process in order to obtain an exact horizontal and vertical position thereof. However, such a solution requires additional mechanical expenditure and the disposal of the cut material. To reduce these disadvantages, e.g. B. proposed in EP-A-293615 for that Closing paper side sacks by clamping the filled sack directly in the filling station and moving it to the subsequent folding station by means of a slide. A disadvantage of this, in itself simple, design is the fact that the open sack end is relatively accurate - can be grasped, but the preformed structure can often only be adopted very imprecisely.

According to EP-A-123784, it is proposed to loosen a paper layer before folding by a few centimeters and to subsequently glue the flap thus formed as protective flaps over the folding point directly to a point of the sack material that lies outside the folding point. This can provide additional security for the bag closure against peeling, even if the adhesive is not optimally attached. A disadvantage here is also a complication of the folding process, which can impair the reliability, in particular with high system output. It is also only used for multi-layer paper.

A similar solution is described in DE-A-2520744, the operator being restricted in the choice of the bag material by a special bag assembly.

The invention is based on the object, while avoiding the disadvantages of the prior art, to develop a method for automatically closing transport bags which enables simple and precise closing of the transport bags with a capacity of approximately 1200 bags per Hour and packaging mass of at least 5 kg to approx. 50 kg per sack. This object is achieved according to the characterizing features of claim 1.

The invention is further based on the object of providing a device for carrying out the method, with a high degree of flexibility with regard to the size and shape of the bags used, preferably being made of paper. The solution according to the invention is characterized in that the free-standing upper edge of a filled transport bag is spread from the inside in a manner known per se and at the same time a side fold is worked in from the outside on both sides and the height of the bag is subsequently aligned. This is followed by a known clamping, however, the aligned sack is fixed in its height in a manner not previously known in order to enable the spreading knife to emerge and is fed to a pre-grooving and first folding. This is followed by further grooving and application of an adhesive film, folding and gluing of both folds.

Through immediate intensive pressing of the glue point in press rolls, a tight connection is achieved, which achieves most of the final strength in the shortest possible time after leaving the glue rolls.

During the entire process, the sack is located on a horizontal base, a transport element, preferably a conveyor chain, and its position is monitored by sensors.

The transport element is adjustable in height and has a secure longitudinal stabilization. This makes it possible to use simple, trapezoidal height adjustment elements.

The bag is preferably moved continuously and constantly after filling and placing on the transport element, also in order to avoid kinking of the bag.

In extensive investigations it was found that the linking of known individual functions with new functions, with the aid of sensor and robotics means as well as controllers, a completely new generation of systems with sometimes surprising results can be created. The device for carrying out the method according to the invention is distinguished by a comparatively low mechanical outlay and space requirement. Previously customary set devices, e.g. B. for cutting the sack edges and disposing of the waste.

The use of robotic means and sensors enables not only precise movements but also the acquisition of manipulated variables in regulated movement sequences. A drifting of manipulated variables can be used to identify changed, external and internal operating conditions known to the person skilled in the art.

Especially when bagging with unstable paper bags and changing properties of the goods to be bagged in the course of minutes or hours as a result of external conditions and conditions, active tracking of specified parameters is essential to maintain trouble-free, automatic and unmanned production.

According to the invention, it has been recognized that the spreading operation of the sack must already take place precisely and with a defined force. A deep immersion of the expansion elements (knives) in the sack close to the surface of the crop also allows air pockets to be squeezed out well. The preferred use of two inner knives and one gusset knife for placing a gusset (or using the gusset knives for spreading a sack without a gusset) results in a transverse spreading of the inner knives before the side fold is pressed in, so that the sack is uniformly stretched all round. Due to the same side lengths of the front and back of the sack, this not only results in a better appearance, but above all a higher tightness of the closure. The spreading elements are moved in coordination with the transport element.

The frictional connection between the spreading knife and the bag wall is used to bring the upper edge of the bag into the correct position by moving the spreading elements down or up with the same drives that perform the diving movement. This is the first time that the open upper part of the sack has been precisely prepared for the actual closing without sack edge cutting or similar manipulations.

The sack is preferably drawn into the closing device such that only a horizontal distance from sack to sack is required on the conveyor belt. This is possible for. B. by a double beak Einzugεystem. A parallel positioning of the front beak parts also makes it possible to move the clamping carriage that can be moved thereon at a constant distance from the sack. The sack is thereby fixed in its position even when the spreading knives are pulled out, while the beaks as holders of the clamping belt are still unclosed held. The clamping force in the beak as well as in the immovable part can be freely selected and reject bags can be removed by releasing the clamping force, if necessary also by selectively releasing the clamping force in the movable or fixed part, in which a missing bag is currently located. The transport element is lowered in parallel.

The sack is advantageously folded in several steps. First, the fold is pre-grooved and folded, regardless of the paper thickness. The grooving rollers are cylindrical, so that the upper part of the roller of the second folder can also serve as a press roller for the first folder.

The height of the folding devices is preferably adjustable in order to enable any folding width. The folding channel is preferably designed such that tensions in the folding area of the sack can be reduced. Sensors for detecting faulty bags are preferably arranged in the area of the pre-grooving (first grooving).

Immediately after the second grooving, the adhesive is applied, the application nozzle preferably being movable in a curve, in order to achieve an optimal position of the adhesive bead and a constant distance from the adhesive edge to the first fold to achieve the entire sack width. Again independent depending on the paper thickness and arched or slightly bent folds.

The gluing point is preferably pressed in pairs in order to achieve a high specific pressure. This results in very short pressing times and, due to good distribution and intensive networking with the paper, a low glue requirement.

The device according to the invention permits continuous and low-man operation with high output, since firstly all movements are recipe-controlled by means of the robotics means, sensors and controllers, secondly in the case of changing conditions, the recipe-related parameters are automatically updated, and thirdly because the freely programmable axes can be program-controlled at any time and can automatically process a different bag format (correction according to recipe control and readjustment after assessment).

The link between the individual stations is the transport element.

The invention is explained below in an exemplary embodiment with reference to a drawing with further details. In the drawing they show

1: the alignment according to the invention after the bag edge has been spread

Fig. 2: the sack spread in steps (as a prerequisite for straightening)

Fig. 3: essential steps of bag folding and gluing

Fig. 4: the closed and glued sack still held by a clamping conveyor belt Fig. 5: the device for the automatic closing of transport bags showing the individual interventions

Fig. 6: the height-adjustable transport element in its extreme positions.

An open in a known manner and in a filling station with z. B. flour-filled sack 1 (transport sack made of paper) is placed on a transport element 3 and accelerated to the required level (cf. FIG. 5) and moved continuously and constantly.

FIG. 1 shows schematically the combination according to the invention of previous spreading and here shown alignment of the bag 1, in particular the bag edge 2. The bag edge 2 can be aligned both horizontally and vertically. It is essential that, after the alignment according to the invention, the edge of the bag 2 is guided through the subsequent processing stage 4 at an unchanged height. For this purpose, a clamping conveyor belt 5 is provided, which can be driven synchronously with the transport element 3.

The height of the sack edge 2 can, for. B. vary due to external conditions such as changed product volume with the same weight or different bag mass.

The main steps of sack spreading are shown in FIG. First of all, the spreading elements are lowered and the inner seaters 6 preferably dip deeply into the sack 1 shortly above the flour level, while one gusset knife 7 is ready on the outside near the narrow sides of the sack 1. By opening the inner knife 6 in the transverse direction, the sack material is stretched into a rectangle, the gusset knives 7 simultaneously moving inwards and forming the gusset 8. In particular, via the gusset knife 7, an adjustable clamping force is generated on the sack material, which allows the sack opening to be aligned by means of all the knives. The transverse spreading by turning the inner 6 outwards gives a uniformly stretched sack 1 before the side fold is pressed in. The rotation for transverse spreading is carried out, for example, by pneumatic cylinders, with the piston and piston rod having a fulcrum at the front on the piston rod or on the piston itself, so that a piston rod guide, a separate swivel joint and thus overall length can be saved.

The use of two inner knives 6 and one gusset knife 7 allows the placement of a gusset 8 or the use of the gusset knife 7 for the internal spreading of bags 1 without the cast set 8, the knife set 7 assuming the starting position of the inner knife 6 and the inner knife 6 in a parking position Assume position of the gusset knife 7. In order to take over such a swapping of the tasks, the total of six knives 6, 7 move on only two rails, not explicitly shown, with a U-shaped gripping of a holder of the inner knives 6 via a carriage of the gusset knives 7. Preferably two motors drive the inner knives 6 and the gusset knives 7 independently of one another on the respective common rails via a traction means in a manner known per se using a forward and returning belt strand. This allows a synchronous, opposite direction of movement of the two matching carriages for inner knife 6 and cast knife 7. The drive chains for the drive pinion of the gusset and inner knife belts also preferably serve as bearing points for the deflecting pinion of the opposite axes. The drive pinion for the inner knife 6 is preferably firmly coupled to the shaft, the deflecting pinion, the gusset knife 7 is loose.

The correct diving starting point of the spreading elements is determined by detecting the bag width via light barriers known per se.

A weight force compensation of the knife holder by pressurized air cylinders acting on one side enables smaller loads driving forces and thus lighter motors to drive the entire axis.

Known robotics, including sensors and controls, ensure a precise, real-time movement.

For the subsequent vertical straightening (FIG. 5), a straightening optic that is adjustable in relation to the bag formats to be processed is provided. The directional optics can easily be placed freely in the coordinate system. The regulation of the height of the upper edge of the sack edge 2 (and thus also the height of the band of the transport element) relative to the spreading device is carried out by comparing the detected direction of travel with a predetermined target direction of travel. Drifting the height of the top edge of the sack edge 2, e.g. B. as a result of different contents, is intercepted by adjusting the height of the belt of the transport element. Permanent observation or manual intervention is therefore not necessary.

The sack 1 is drawn into the closing unit by a double-beak pull-in system (FIG. 1, clamping device 9), whereby a sack spacing on the transport element 3 in the order of the sack width is possible. The beak construction with a double joint enables the front pair of beaks to be placed in parallel, which enables the mounting of the clamping carriage (clamping conveyor belt 5) on clamping carriage rails aligned parallel to the direction of travel of the bag 1 and thus enables the clamping carriage to be moved at a constant distance from the bag 1.

The "ready-spread" sack 1 is held by the clamping carriage while the inner knife 6 is being moved out of the sack 1 (FIG. 5) in order to avoid changes in position of the sack 1 at a point in time at which the clamping band is not yet closed, but the inner knife 6 is already move out of bag 1. The clamp carriage is transported back without its own drive simply by frictional engagement on the returning clamp band strand.

The sack 1 is clamped for synchronous transport through the closing device by means of vertically guided profile toothed belts, pneumatically pressed on, which enables a freely selectable setting of the clamping force with a low-effort pressure control. The pressure pistons are located in a cylinder that is open at the front, a lip acts on the front as a wiper and on the cylinder side as a seal.

Reject bags u. The like can be automatically removed by discharging the clamping band air in sectors in the area of the relevant bag 1 and lowering the transport element 3.

FIG. 3 shows the main steps of folding and gluing the open edge of the bag 2 of the clamped bag 1. A first pair of grooving rollers 9 produces a first grooving 10 (pre-grooving). The first fold is then produced via a first folding device 12. A second pair of grooving rollers 13 subsequently produces a second grooving 14. Then an adhesive film 16 is applied in a manner to be described via a glue nozzle 15. This is immediately followed by the second folding by a second folding device 17, whereupon the double fold 18 formed is brought to a firm and flat bond in a pair of press rollers 19.

The adhesive site is subsequently passively cooled in a manner known per se by the ambient air, and the closed bag 1 is then passed on for further treatment (palletizing or the like).

By pre-grooving (grooving 10), loose folding of the fold 11 in a spiral channel of the folding device 12 is possible with little friction and regardless of the paper thickness of the bag 1. Due to the cylindrical design of the grooving rollers 9, 13, the grooving roller 13 can also serve as a press roller for the first fold 11. It is only one roller is driven, the respective second pair is driven by the friction on the circumference, so that mechanical overdriving can be avoided.

The fold height and fold position are automatically adjustable, so that the length of the closed bag 1 can be freely selected for optimal adaptation to the pallet size.

The formation of the folding channel as a shaft with parallel side walls, between which the folded-over part of the sack runs after passing the spiral folder, enables the reduction of tensions in the folding area, caused by uneven lengths, through which the leading edge of the fold traverses the part in the folding area Has. This not only results in a straight fold 11, but also the possibility of an extremely short spiral chuck if no higher demands are made on the straightness of the fold 11.

By means of optical limit switches (which can be positioned depending on the folding width) after the first grooving rollers 9, incorrectly aligned bags 1 can be identified and sorted out. Likewise, bags 1 with wrong weight u. a. be expelled.

In general, missing bags are ejected later at the end of the closing device in order to exclude that such missing bags are placed on a palletizer or the like. reach.

The glue nozzle 15 is fixed on a position axis perpendicular to the fold axis or arranged to be curved. With a curve control, an adhesive film 16 extending parallel to this fold 11 can be applied, in particular also in its initial area, in spite of typically a slightly curved / folded fold 11. Likewise, different thicknesses of the adhesive film 16 or an adhesive bead can be corrected in such a way that the adhesive reaches exactly to the lower fold edge after pressing.

Different paper thicknesses with the same setting of the folding position result in unevenly wide folds as a result of an unequal long neutral fiber in the bending radius. This shifts the absolute position of the ideal adhesive application line. This typical behavior can be corrected by means of curve control and recipe management for each bag format.

When starting and stopping the glue nozzle 15, the applied adhesive bead or film 16 falls on the first and last millimeters. After pressing, this affects the width of the adhesive film 16. In order to correct the resulting fish shape and to bring the adhesive edge into line with the fold edge, the curve control is used.

The use of a pair of press rolls 19 instead of a conventional, longer press section enables a very high pressure of the adhesive on a line with a low power requirement. The high specific pressure (calender-like) enables the adhesive to be rolled out into a thin film with widespread wetting of the paper right into the material pores and thus a large adhesive surface. This is important in order to prevent the closure from tearing open even during peeling movements.

In addition, a thin adhesive film 16 is flexible under bending stress, has less tendency to tear open compared to conventionally compressed and thick adhesive points between tapes, and less adhesive is used. Likewise, the cooling time is shorter and the bag 1 can be loaded immediately after leaving the press rolls 19. The pressing time is approx. 1/2 second and approx. 80% of the final strength is reached immediately. Extensive tests have not revealed any peeling problems. The overall length of the closing device is also reduced.

Like the grooving rollers 9, 13, only one pressing roller 19 is driven and the second is driven by the friction on the circumference. The force flow on the circumference is always maintained, with or without a clamped sack 1. An entire closing device is shown in FIG. The spreading device has independently controllable drives 20, 21 for the inner knives 6 and cast iron knives 7, which allow height adjustment on one or both sides and subsequent alignment. By means of a fluid drive or position drive (inner knife 6), not shown drives, the knives can be moved horizontally and a clamping force can be applied accordingly. The spreading device can be moved on a horizontal guide rail 22 parallel to the transport element 3 in order to synchronize the spreader with the bag 1 and to exclude disturbing forces during the spreading. The alignment function is carried out via sensors 23, e.g. B. light sensor is monitored and can be controlled or regulated by means of a process computer.

The filled bag 1 is brought from a bagging station 24 onto the transport element 3, with a side guide 25 holding the bag 1 vertically. For reasons of high functional reliability, the bags 1 should be uniform and spaced short.

The transport element 3 (FIG. 6) can be adjusted in height by means of lifting trapezoids 26.

The use of the integrated machine control sensor system for the simultaneous detection of incorrect behavior of the bags 1 via an object-related memory enables the bags 1 to be ejected at the location set up for this purpose.

The use of computer controls also enables bag-specific recipes to be managed and, via freely programmable axes, an automatic adjustment to other bag formats is provided. Incorrect settings when changing the format are almost excluded. Machine and process-specific peculiarities can be corrected, the controller automatically adjusts to changing internal and external conditions by storing controller values even when working in batches. List of abbreviations

bag

Sack edge

Transport element

Clamping device

Clamp conveyor

Inner knife

Gusset knife

Gusset

Grooving roller

Creasing

Fold

Folding device

Grooving roller

Creasing

Glue nozzle

Adhesive film

Folding device

Double fold

Press roll

drive

Guide rail

sensor

Bagging station

Side guide

Hu trapeze

Claims

claims

1. Method for the automatic closing of transport bags after filling with a predetermined filling quantity of bulk goods and conveying to a closing device with subsequent clamping of the transport bag, folding and gluing / gluing of the upper, open bag edge as well as subsequent pressing and cooling of the Adhesive point, characterized in that the transport bag (sack (1)) is additionally aligned and fixed in its height with respect to the upper sack edge (2) after the open sack (1) has been spread open, by contracting air from the Sack (1) is pressed and the aligned sack (1) is transferred to a double-cable pull-in system of the closing device, the fixed and aligned sack (1) is pulled together and clamped twice in a pull-in system, followed by a first grooving (10) and a first Fold (11) is formed, then a second groove arranged below the first tion is carried out (14) and applied below this second grooving (14) an adhesive film (16), anschlieεεend a double seam (18) to form a strip produced Kleb¬ and gepreεεt high Flächenpreεεung,

wherein the sack (1) is moved horizontally on a transport element (3) continuously and constantly forwards.

2. The method according to claim 1, characterized in that the sack (1) is aligned via the clamping force of the spreading device, the sack (1) being moved wholly or partially.

3. The method according to claim 1, characterized in that air spreads inside the sack are removed when the sack (1), which is open at the top, is spread and clamped.

4. The method according to claim 1 and 2, characterized in that the free end of the bag (bag edge (2)) is brought into a preselectable height position.

5. The method according to claim 1 and 2, characterized in that the spreading device transfers the stretched, contracted and aligned bag (1) to a clamping conveyor belt (5) by means of a clamping carriage, the clamping conveyor belt (5) synchronizing the bag (1) with the transport element ( 3) carries along.

6. The method according to claim 1, characterized in that faulty bags are sorted out by selectively releasing the clamping force in a movable or fixed part of the double beaks and parallel lowering of the transport element (3).

7. The method according to claim 1, characterized in that the upper end of the sack is contracted by two inner knives (6) that open and close at an angle after being immersed in the sack (1) and one on each side from the outside between the closing ends Inner knife (6) traveling knife set (7) follows, forming a knife set (8), the knives (6, 7) being moved in a coordinated manner in the direction of transport.

8. The method according to claim 7, characterized in that the casting set (8) coordinates by moving the inner knife (6) back into a parallel position with the retracting movement of the casting knife (7) under tension of the bag material in the transport direction of the bag (1 ) is formed.

9. The method according to claim 1, characterized in that the height of the transport element (3) is adjustable.

10. The method according to Anεpruch 1 and 5, characterized in that the open and contracted bag end from the contraction in the clamping conveyor belt (5) in unchanged alignment or Höhen¬ position until pressed and carried synchronously to the transport element (3) .

11. The method according to claim 1, characterized in that the fold is formed in a spiral folder and a folding channel, the length of which preferably corresponds to the fold length.

12. The method according to claim 1, characterized in that daεε daε application of the adhesive with a curve-controlled glue nozzle (15).

13. The method according to claim 1, characterized in that the second grooving (14) and the application of the adhesive film

(16) take place simultaneously.

14. The method according to claim 1, characterized in that the adhesive strip is produced sealingly between the first fold (11) and the adhesive application point.

15. Device for the automatic closing of transport bags after filling with a predetermined quantity of bulk material with stations for spreading, clamping and folding the transport bag, gluing and pressing the glue point, the bag moving from station to station on a conveyor belt-like transport element characterized in that it has a spreading device with a controllable drive for spreading and height adjustment of the bag (1), a clamping device (4) with a clamping conveyor belt (5), two pairs of grooving rollers (9, 13) arranged one after the other in the transport direction. which are each followed by folding devices (12, 17), a glue nozzle (15) for applying an adhesive film (16) being arranged between the grooving rolls (13) and the folding device (17) and a pair of press rolls (19) ow as well as arranged downstream Contains sensors, robotic means and controllers.

16. Device according to claim 15, characterized in that the spreading device has two pairs of horizontally and vertically movable inner knives (6) and a left and right side cast knife (7).

17. Device according to claim 15 and 16, characterized in that the inner knives (6) are assigned a separate drive for opening and closing.

18. Device according to claim 15 (and 17), characterized gekenn¬ characterized in that drive chains for drive pinions of inner meεεerriemen and Guεεetmeεserriemen serve as bearing points for idler sprockets of the opposite axis and preferably the drive pinion for the inner knives (6) firmly with coupled to the shaft, however, the deflection pinion of the gusset knife (7) is loose.

19. Device according to claim 15 and 16, characterized gekennzeich¬ net that daεε εie sensors for determining the position and height of the upper sack edge (2).

20. Device according to claim 15, characterized in that only one roller is driven in each case by the grooving rollers (9, 13) and pressing rollers (19) arranged in pairs.

21. Device according to claim 15, characterized in that the glue nozzle (15) is curve-controlled.

22. Device according to claim 15, characterized in that the transport element (3) is adjustable in height and preferably has two lifting trapezoids (26) coordinated by a common propeller shaft and at least one articulated lever longitudinal link for longitudinal stabilization.

23. Device according to claim 15, characterized in that it has control means and regulating devices for preselectability of the folding height, furthermore means for prescription control and definition of the Contains the height of the sack fold or the finished sack length as well as for the independent height adjustment of the folding devices ((12, 17) and for the detection and sorting out of faulty sacks.