EP0363359A1

EP0363359A1 - Device for depositing and stacking plastic bags with seamed lower edges

Info

Publication number: EP0363359A1
Application number: EP88901590A
Authority: EP
Inventors: Hans Reifenhäuser
Original assignee: STIEGLER GmbH MASCHINENFABRIK
Current assignee: STIEGLER GmbH MASCHINENFABRIK
Priority date: 1987-02-14
Filing date: 1988-02-10
Publication date: 1990-04-18
Also published as: WO1988006091A1; DE3704663A1; US5030191A; DE3704663C2; AU1243288A; DE8717635U1

Abstract

Un dispositif d'entreposage et d'empilage de sachets en plastique (1) soudés à leur partie inférieure (7) comprend des éléments verticaux de retenue (21) fixés sur des traverses (20) reliées par des charnières à la circonférence extérieure d'un support rotatif ayant en particulier la forme d'une roue à ailettes. Les traverse s'étendent transversalement à la direction d'avancement des sachets produits et sont montées sur le support de telle sorte que pendant leur rotation les éléments de retenue (21) gardent leur position verticale.A device for storing and stacking plastic bags (1) welded at their lower part (7) comprises vertical retaining elements (21) fixed on crosspieces (20) connected by hinges to the outer circumference of a rotary support having in particular the shape of a fin wheel. The cross members extend transversely to the direction of advance of the produced bags and are mounted on the support so that during their rotation the retaining elements (21) keep their vertical position.

Description

_ __

Device for depositing and stacking bags made of plastic films with bottom seam

The invention relates to a device for depositing and stacking bags with bottom seam, which are made from a batch of tubular film made of thermoplastic material by welding and cutting transversely to the direction of advance, with ta working welding and cutting device for welding the bottom seam and Separating the bags transversely to the feed direction and with a downstream stacking and conveying device with strip-shaped traverses fastened transversely to the feed direction on a movable support, which are equipped with vertically upward holding elements in the form of pins, stacking tubes or the like on which the separated bags are placed become.

A generic device is known for example from DE-OS 23 05 800, in which the holding elements for receiving the bags are rigidly attached to endless, intermittent belts and are oriented vertically upward only in the receiving position for the bags. The bags are gripped by the holding elements before they are separated from the tubular film. With this device, the bags can be stored loosely in stacks, the simultaneous blocking of the bags in stacks at the depositing point cannot be carried out.

Devices for producing interlocked stacks of bags with bottom seam are for example from DE-OS 22 54 448 and

23 58 281, for those separated from the tubular film _B Eutel a single transverse to the feed direction arranged liftable and lowerable strip with vertically upwardly directed holding elements is provided, which means are associated for perforating and welding. Similar devices for manufacturing, possibly blocked. Stacking bags with bottom seam with .only one bar with vertical holding elements, such as needles, show DE-OS 32 11 217, DE-OS 30 21 868, DE-OS 31 00 722, DE-AS 21 41 045 and US-PS 42 61 780.

From DE-OS 30 26 494 a device for stacking and depositing bags with side seams is known which, after being ^' separated from the tubular film, transported individually from the arms of a rotating impeller under vacuum and arranged rotatably on the horizontal feed plane Holding strips with vertical pins are stacked. The holding strips are additionally designed to be tiltable for dispensing the stack.

However, this method of lifting and stacking side seam bags is not applicable to bottom seam bags, in which the bottom seam is welded transversely to the feed direction and the bag opening with the hanging holes also runs transversely to the feed direction with a corresponding feed.

Bags with bottom seams, however, have bags with

Side seams have the advantage that they achieve a much higher filling volume with inserted side gussets.

The invention has for its object to enable the placement and stacking of bottom seam bags on holding elements and also the transfer to wire brackets (on Wiσkets) or the blocking of bags deposited in such a way. The device is intended to enable a production process of the bags with bottom seam made of thermoplastic plastic films that can be carried out without interruption, ie without empty cycles, at high production speed. To achieve the above object, a device of the generic type is designed in such a way that the crossbeams are articulated and guided on the circumference of the rotatably, in particular in the manner of an impeller, and arranged vertically to the plane of the lift, so that the crossbeams are in circulation with the support, the holding elements maintain their vertically aligned position.

The stacking and conveying device according to the invention is designed as a rotary pin stacker, the deposited stacks are moved in batches on a circular path in the vertical plane; Bags with bottom seams can be stacked in a variety of designs. The stacks can be stored loosely or blocked and hung in wickets. Blocking welds and punching holes for the wicket hoops can be carried out together. The holding elements can be designed as pins for hanging the bags on their hanging holes or with needles for picking up the bags.

According to a preferred embodiment of the invention, the rotary carrier is equipped with eight cross members arranged at uniform intervals over the circumference and has a corresponding number of eight standstill positions during one revolution, which can be reached step by step from the individual cross members in a stacking cycle. In the preferred direction of rotation of the carrier, the traverses can be moved further from the receiving position of the bags into a higher position. For the wrapping of the bags, a feed device for wicket stirrups is assigned to a rest position of a traverse following the receiving position.

The rotation carrier for the crossbeams is designed, for example, in such a way that the crossbeams can be separated from one another by the number of the same distances over the circumference

Rotary bearer are distributed. The number of trusses and the size also depend on the maximum to be put down _B eutellänge, at, for example 600 mm maximum bag length are provided 6 or 8 traverses. Two or more bags can also be placed next to each other in multi-lane production. The distance between the individual trusses should be at least about half of the maximum bag length. The _traverses, - are mounted on the side constituting the rotation wing support rods, the end points of a polygon corresponding to the number of the crosspieces with a corresponding number of resting positions, forming in a recirculating path. At least the following working positions in the direction of circulation are provided in succession on a circulation route:

a) Pick-up station of the bags immediately behind the welding device

b) an intermediate stop position

c) a wire clip feed station

d) an acceptance station for the stack of bags.

Furthermore, the drive of the rotation carrier can be controlled by a counter which is pulse-controlled by the welding station for a cyclical rotation after the number of bags specified for a stack has been reached, corresponding to the number of weldings carried out, by an angle corresponding to the spacing of the crossbeams.

To receive and stack the bags, the trusses are equipped with stacking tubes that are open on one side in particular, usually in accordance with the arrangement of pairs

Hanging holes, also in pairs. The stacking tubes are screwed, for example, at predetermined intervals from one another into threaded holes predrilled in the crossbeams. Depending on the bag, film web and machine width, several pairs of stacking tubes can be arranged side by side on the trusses; eg two pairs for two-lane operation, three pairs for three-lane operation, etc. The crossbeams with the holding elements are guided in the side wing bars of the rotary carrier in such a way that the crossbeams do not twist as they rotate and thus the holding elements, such as stacking tubes and pins, always remain unchanged in the vertical position.

The diameter of the holding elements, such as stacking tubes, is in relation to the diameter of the opening holes punched into the bags, for example if the suspension holes have a diameter of 12 mm, the stacking tube should have a smaller outside diameter of, for example, 6 to 8 mm. ^" - ^■■

The correct positioning of the stacking tubes at the stacking position of the bags, ie immediately behind the welding device, is important. It must be taken into account that the required distance between the top of the hanging hole and the top of the bag can be strictly observed, since this guarantees that the bag will be torn off cleanly from the blocked stack during subsequent filling. Punching the hanging holes including

Tear-off perforation slit takes place in particular immediately in front of the welding and cutting station, so that this guarantees positioning within a minimum tolerance range, i.e. within the feed and section length tolerance is possible. The device according to the invention is therefore designed in such a way that the rotation support is subsequently assigned to the welding and separation station and that the top position of the holding elements of a cross member is aligned with the transport plane of the film tube or slightly below the same, in a position of the rotation support that serves to hold the bag

Λ lie. It is further provided that in the space between the welding beam of the welding station which can be carried out a lifting movement transversely to the transport plane and a traverse in the bag receiving position, a lifting movement which can be carried out parallel to the welding beam is carried out immediately in succession Cutting knife above, a support bar below and a lifting movement executable pressure bar are arranged above the transport level. This means that the bags can be stacked on the holding elements of the traverses directly in connection with or after the welding and cutting process. After the feed transport has been completed, the bags remain exactly above the stacking tube in the area of the hanging holes and are opened onto the holding elements simultaneously or immediately after the cutting process by, for example, a pneumatically operated print bar. This pressure bar can optionally also be equipped with spot welding heads "in order to block the bags in the area of the bag opening or their upper flap when stacked on top of each other to form a 3-bag stack.

For the cutting process within the welding and

Cutting device, it is important to be able to use a heated cutting knife, which enables a clean cut and a long service life of the cutting knife.

The welding, cutting and bag stacking system according to the invention almost completely rules out malfunctions in automatic production and thus offers a very high level of production reliability and economy.

In order to reduce the weight of the stacked bags hanging on the crossbeam and at the same time to reduce the point load at the upper edge of the hanging lugs of the bags and to avoid tearing, the crossbeams are equipped with storage combs, which are particularly curved in

The feed direction, sloping downwards, serves as a support for the bags. This also delays the fall of the bag bottom provided with the weld seam and promotes cooling of the weld seam, so that sticking of the weld seams is avoided.

For better lateral guidance of the bags during the stacking process can be attached to the truss guide plates. Between the pick-up positions of the individual comb fingers of the storage combs, the traverses are provided on the upper side with groove cutouts which serve to immerse the take-over comb for the stack of bags when the same is removed from the removal station of the rotary carrier for forwarding to the packaging.

The invention is illustrated by way of example in the drawing. Show it

10 Figure 1, 2 and 3 three different bottom seam bags in view

Figure 4 shows the schematic supervision of the manufacture of the bag from a film tube

5 shows the schematic front view of a ^"

Traverse with a stacked bag

Figure 6 shows the schematic supervision of a

Stacking tube 0

Figure 7 and 8 with the welding and cutting station

Bag transfer to the traverse in a schematic representation during welding 5

Figure 9 is a schematic representation of the welding and cutting station with stacking and conveying device with 'rotation carrier in a schematic representation. 0

Figures 1 to 3 show examples of bags 1 made of thermoplastic plastic film with bottom weld seam 7 and inserted side gussets 2. The bags have in the area of the bag opening 6. an upper flap 4 projecting on one side on the rear wall with two hanging holes 3, at a small distance in the direction the tear-off perforation slots 5 are assigned to the outer edge of the tab. These bags _k LEVERAGING, as shown in Figure 3, yet a punched _G riffloch 10 have. In addition, they can also have a tear-off perforation line 11 above the bag opening 6, along which the bag 1 can be torn from the upper flap 4. The bags can also be blocked together in the stack in the area of the upper flap by spot welds 8, as shown in FIG. 2. If necessary, these spot welds can be punched out, for example, along the lines 9 shown in broken lines. These can also be designed as tear-off perforations 9. The bags 1 arranged one above the other in a stack can then be held on wickets or wire hangers inserted through the hanging holes 3. The bottom seam bags with side gussets and top flap shown in FIGS. 1 to 3 can be filled very easily since the front wall is exposed at the bag opening 6 below the hanging holes 3. Bags with a bottom seam without an upper flap can also be formed, in which the hanging holes 3 go through both bag walls.

FIG. 4 schematically shows the development of the bag 1 according to FIG. 1 in the case of two-lane manufacture from a film tube 100 with feed direction A. First, the side gussets 5 are inserted into the film tubes, then in a cutting and punching station I by cutting out an upper side Foil strip configured the top tab 4 and punched the hanging holes 3 and tear-off perforation slots 5. Thereafter, the film web 100 is continued in cycles by one bag length through the welding and separating station II, and the bottom weld seam 7 for closing the end of the film tube and the separating cut 12 for separating the leading bag 1 are carried out. Thereafter, the film tube is continued in a position corresponding to the desired bag length with the bottom seam first and, in the advanced position, the area adjacent to the separating cut to be produced with the receiving holes is positioned via correspondingly assigned holding elements 21 and then simultaneously with or immediately after the implementation the cut pressed on the holding elements. After reaching the number of bags preselected on the holding elements by means of a counter, the holding elements are continued in the stacking cycle on a circular circulation path that starts upwards. The holding elements are advanced immediately after the placement and cutting of the last bag belonging to a stack has been completed while the associated process of welding the bottom seam of the next bag is carried out.

7, 8 and 9, station II and the subsequent storage, stacking and conveying device are shown schematically in detail. The film web 100, which is already equipped with the top flap 4 and the suspension holes 3 with tear-off perforation slot 5, is advanced in the feed direction A by means of feed rollers 31 through a comb guide 32 until the set bag length is reached

Welding device 33a, 33b advanced in sections. After passing the welding device towards the bottom seam at the end of the bag, the film web which is loose is initially supported on the "underside arranged transversely to the feed direction

Support bar 35, see Figure 7. Then the upper part of the welding device with welding bar 33a, cutting knife 34 and bag pull-off bar 36 lowers. Of these elements, the cutting knife 34 and the bag pull-off strip 36 simultaneously touch the film web 100 and perform the separating cut and the pressing down of the bag separated by the cut along the support strip 35 up to and below it, see FIG from the pre-punched suspension holes 3 on the associated holding elements, for example stacking tubes 21, while .seam welding 7 is carried out along the other side of the cut edge. The holding elements are with their heads directly below the feed plane, i.e. Welding level arranged.

The stacking tubes 21 are equipped, for example, with a slot 211 on one side for wire clips, see FIG. 6. The holding elements 21 are fastened on cross members 20, for example round rods or square strips, for example screwed in. The cross members preferably have a plurality of screw-in holes for receiving the desired number of holding elements for different distances. In the case of two-lane bag production, each with two hanging holes, two pairs of holding elements 21 are provided next to one another at a corresponding distance, as can be seen, for example, from the view in FIG. The traverses .20 are articulated and guided on the circumference of the rotation carrier 40. The carrier

10 40 is designed as an impeller with wing bars extending radially from the hub ~ ^' -41 and tangential to the ends of the wing bars associated guides 42 which guide the ends 202 of the crossbeams, see FIGS. 5 and 9. The guides 42 have the effect that when the carrier 40 rotates in the direction of the arrow C, ^L, the stacking tubes 21 on the cross members maintain their vertical position even during the entire rotation of the cross members with the rotary carrier 40. In the example shown, the rotation carrier 40 is equipped with eight cross members 20, which are arranged evenly distributed over the circumference. The rotation carrier is arranged immediately after the welding device in such a way that, as explained with reference to FIGS. 7 and 8, the cut-off bags 1 can be automatically stacked on the holding elements 21 of the cross members.

5 After reaching the preselected via a not-shown counter bag number per stack 50 on the support members of a truss _^ Ro ationsträger 40 rotates about a one pitch length E corresponding angle in the direction of arrow C. In Figure 9 would be in the position 40a stored pile 50 can be moved to position 40b with 0 of the traverse. This

Rotational feed takes place immediately after completion of the Ablagvorga ges of the last bag on the holding elements 21 of position 40a, that is, still during the welding process. It is thereby achieved that the next traverse, which 5 is still in position 40h, is already in the working position before or immediately after the next stack transport has started, that is to say. be moved to position 40a 1 can and the production process can continue continuously.

During the formation of the next stack of bags in position _r 40a, the stack transported in position 40b remains. The o

Position 40c is assigned a feed device for wire bracket 30. Beer is automatically fed wire stirrups 30 in the direction of arrow F from a magazine arranged above position 40c, i.e. inserted from above into the holding elements designed as stacking tubes according to FIG. 6. With the next feed, which takes place with an eighth revolution of the rotary carrier 40, the stack of bags equipped with the wire clips 30 reaches the position 40d. Here, the stack of bags 1 can be removed by robotic hand from the stack tubes, which are open on one side, and can be placed in the packaging boxes provided. The schematically indicated robotic hand 29 can be designed in the form of a take-over comb which dips into the groove recess 26 of the crossmember 20, see FIG. 5, by immersing the stack of bags and removing it from the stacking tube by lifting it up.

The empty cross beams then pass from the receiving station 40d through the space stations 40e, 40f, 40g and 40h back to the ^{'bag-mounting} station 40a. To support the exact position of the bags placed on the holding elements of the trusses, the trusses can be provided on the upper side with guide plates 25, which can be adjusted depending on the width of the bags to be placed.

It is also possible to design the device so ^'that simultaneity ^ spot welding in the region of the side of the peg holes of the stacked bags is carried out with the pressing of the bag on the holding elements, which is placed on the stack of each bag on the stack is welded or stapled.

Claims

A IPatent claims

1.Device for depositing and stacking bags with a bottom seam, which are produced from a tubular film made of thermoplastic material which is moved in batches in the feed direction by welding and separating transversely to the feed direction, with intermittently operating welding and cutting device for welding the bottom seam and severing the bags transversely to the feed direction and with a downstream stacking and conveying device with strip-shaped crossbeams fastened transversely to the feed direction on a movable support, which are equipped with vertically 5 upward holding elements in the form of pins, stacking tubes or the like on which the separated bags are placed, thereby characterized in that the traverses (20) on the circumference of the rotatable, in particular in the manner of an impeller, "executed and arranged vertically to the feed plane

Carrier (40) are articulated and guided so that on the circumferential path of the trusses with the carrier

Holding elements (21) maintain their vertically aligned position. 5

2. Apparatus according to claim 1, characterized in that the rotary carrier is equipped with eight cross members (20) arranged at uniform intervals over the circumference and has a corresponding number of eight standstill positions during one revolution, which gradually progresses from the individual cross members in the stacking cycle can be reached one after the other.

3. Device according to one of claims 1 or 2, characterized in that the direction of rotation of the Rotation carrier (40) is selected so that the crossbeams can be moved further from the receiving position for the bag into a higher position lying above it.

4. Device according to one of claims 2 to 3, characterized in that a feed device for wicket brackets is assigned to a rest position of a traverse following the receiving position.

5. Device according to one of claims 1 to 4, characterized in that the drive of the rotation carrier (40) from a pulse-controlled by the welding station counter for a cyclical rotation after reaching the predetermined number of bags for a stack according to the number of welds carried out an angle corresponding to the spacing of the crossbeams can be controlled.

6. Device according to one of claims 1 to 5, characterized in that the traverses (20) are equipped with leading combs (24) which are slightly inclined downward in the direction of advance.

7. The device according to claim 6, characterized in that the cross members have groove recesses (26) on the upper side, which are arranged axially offset to the storage combs (24).

8. Device according to one of claims 1 to 7,. .- characterized in that the rotation carrier (40) is subsequently assigned to the welding and cutting station. and a standstill position of the Rotati .on ^' s> carrier which serves to hold the bag, the upper ends of the holding elements

(21) a traverse with the transport level of the

Align the film tube or lie slightly below it.

9. Device according to one of claims 1 to 8, characterized in that in the space between the above the transport plane arranged transversely to this a lifting movement executable welding bar (33a) of the welding station and a traverse (20) located in the bag receiving position immediately in succession and parallel for the welding beam, a cutting knife (34) which can be carried out a lifting movement, a support bar (35) below and a pressing bar (36) which can be carrying out a lifting movement are arranged above the transport plane.

10. The device according to claim 9, characterized in that the pressure bar (36) is equipped with spot welding heads.