WO2000020195A1

WO2000020195A1 - Device for opening tubular bag shapes

Info

Publication number: WO2000020195A1
Application number: PCT/AT1999/000235
Authority: WO
Inventors: Franz Starlinger Huemer; Gerhard Apfler
Original assignee: Starlinger & Co. Gesellschaft M.B.H.
Priority date: 1998-10-05
Filing date: 1999-10-04
Publication date: 2000-04-13
Also published as: ATA165798A; BG104454A; DE59902331D1; AU6181199A; BG63529B1; KR100461214B1; EP1035967A1; ID26825A; TR200001537T1; CZ294286B6; CA2313072C; PT1035967E; EP1035967B1; CA2313072A1; JP3753941B2; JP2002526285A; KR20010032340A; BR9906847A; CZ20001813A3; AT406755B

Abstract

The invention relates to a device for opening tubular bag shapes which are open at at least at one end, comprising at least one slide which can be introduced into an open end of a bag between the bag walls, in order to at least partially fold over at least one end area of a bag wall. According to the invention, the at least one slide (3) can be moved in and out of the bag end to be opened by means of at least one, driven cam (9) which can be moved along a predetermined path (8) and which engages with the slide (3). The slide (3) preferably takes a circular path (4), said circular path comprising a section which runs parallel to a bag-transporting device. The speed of transportation of the bags (2, 2a) on the conveyor device (1) and that of the slide (3) around the circular path are equal.

Description

Device for opening tubular bag bodies

The invention relates to a device for opening tubular sack bodies that are open at at least one end, with at least one slider that can be inserted between sack body walls into an open end of a sack body in order to at least partially fold over at least one end region of a sack body wall, the at least one slider passing through a device for moving a respective slide back and forth into the bag body end to be opened and out of it can be moved

The manufacture of sacks usually involves the provision of material hoses which have been obtained either by producing tubular material webs or joining the longitudinal edges of flat material webs into a tubular structure, cutting the material hoses into sack bodies of suitable length and forming a sack bottom by suitably folding and closing one end of the bag body. A sack with a rectangular bottom produced in this way is referred to by experts as a box sack. In order to form the bottom of such a box sack, the end part of the flat body of the sack is placed on top of one another! sack body walls folded along a fold line lying transversely to the longitudinal axis of the sack body, whereby the end of the sack body receives a hexagonal folding configuration with two parallel opposite edges and two times two parallel opposite folding edges. By folding the two edges towards one another and attaching the folding flaps containing the edges to one another or to a cover sheet, the bag body is given a bottom which assumes a rectangular shape when the finished bag is unfolded. Before folding the edges towards one another, a valve sheet can be applied, which is tubular in shape when the end of the bag body is finally folded. Two systems are currently known to fold over the open end of a bag body so that the bottom of a box bag can be formed. Incidentally, this folding is referred to in specialist circles as "opening" the sack body.

The first known system comprises a continuously movable spreading mechanism which is sensitive and requires extensive adjustments and readjustments.

The second system comprises a conveyor belt that is movable in stop and go mode, on which the bag bodies are transported with their longitudinal axis lying transversely to the direction of conveyance to an opening station at which the conveyor belt stops. At the opening station, the edges of the sack body end to be opened are pulled slightly apart and a transversely movable but otherwise fixedly mounted slide moves into the sack body end and folds back part of the upper sack body wall, thereby creating the above-mentioned hexagonal folding configuration. The fold line along which the slider folds the bag body wall is defined by a bar that is located above the bag body in the direction of transport and is lowered onto the bag body after the tape has stopped and holds it at the same time, with the slider inside the bag body moved the bar away. After folding, the slide is pulled back, the bar is lifted and the conveyor belt with the folded bag body can continue to move. The slide is moved back and forth by a pneumatic piston-cylinder system in a generally horizontal plane in which the bag body also lies on the conveyor belt. A disadvantage of this arrangement is first of all the necessary stop-go operation, which leads to high wear and high energy consumption and furthermore limits the production speed, since the bag body must remain in the rest position during the entire slide movement. Further disadvantages of this prior art system are discussed in the description below based on the explanation of the present invention. Another known device is described in DE-A-1 51 1 021, which discloses a method and a device for producing the cross bottoms on tube sections for forming cross bottom sacks. This continuously operating device has slides which are guided in sections along an orbit parallel to the transport direction of the bag body, the slide and bag body moving at the same speed. So that the slides can be inserted into the open ends of the bag body, they are at least temporarily guided along a path inclined to the horizontal, which is designed as a guide rail on which the slides each roll by means of a control roller.

The present invention provides a device of the type mentioned at the outset which overcomes the disadvantages of the prior art, is robust, reliable and requires little maintenance and permits a production speed which goes far beyond the systems known today.

These advantages are achieved in that, in the device mentioned at the outset, the device for the reciprocating movement of a respective slide comprises at least one driven cam which is movable along a predetermined path and which engages the slide in order to move it back and forth. This construction according to the invention is particularly suitable for continuous operation since, apart from the back and forth movement of the slides in the device, essentially only rotational movements are involved which are compared to translational movements, such as in the device according to DE-A-1 51 1 021 used, bring significantly less wear and tear and reduced drive energies.

In a preferred embodiment of the invention, the at least one cam is mounted on a driven chain or belt, which rotates around wheels or pulleys, with a first, by the wheels, the bag body Approximate circulation section, a second circulation section leading away from the bag body and a third circulation section, which forms a cam return section, are defined. Optionally, a fourth circulation section can be provided between the first and second circulation section, which is at a substantially constant distance from the bag body end to be opened. A cam moving in the first circulation section moves the slide assigned to it into the open end of the corresponding sack body, while the cam, when it enters the second circulation section, pulls the slide back again. The fourth circulation section serves to keep the slide in a rest position for a predetermined time with respect to the bag body, during which further process steps can be carried out on the bag body.

In order to be able to change the chronological sequence of the movements of the respective slide, it is advantageous if the positions of at least one of the wheels or pulleys of the device for the reciprocation of a respective slide can be adjusted.

An advantageous embodiment of the invention is characterized in that each slide has a guideway for sliding engagement with cams. The guideway of each slide for sliding engagement with the cams can advantageously be a U-profile fixed to the slide with open ends, the longitudinal axis of which is arranged at right angles to the direction of the reciprocating movement of the slide.

Although the slides can be permanently mounted on a processing station, all the advantages of the invention only come into their own when the slides themselves move in unison with the bag bodies to be opened. Therefore, in a preferred embodiment, a conveyor device for transporting the bag bodies and a drive device for moving the slider along an orbit are provided, the drive of the conveyor device and the drive device for moving the slider along the orbit are synchronized so that in operation the transport speed (arrow A) of the bag body on the conveyor is substantially equal to the speed (arrow C) of the slide along the orbit.

In principle, it is desirable to arrange at least two sliders on the orbit at regular intervals to take advantage of the system. Otherwise, long distances would have to be maintained between the individual bag bodies being transported in order to give the slide time to return to its initial position at the orbit. The number of slides provided means that the time it takes for a single slider to open a bag body is hardly significant, since it can be divided by the total number of slides used and can thus be reduced practically as desired.

So that the use of several moving, equally spaced sliders along their orbit with a common cam drive is possible, the speed of the chain or belt with the cams is set so that it is higher than that of the slider around the orbit.

Advantageously, the drive device for moving the slide along the orbit comprises a chain rotating around gear wheels or a belt rotating around pulleys, the chain or belt being connected to the slide and at least one of the gear wheels or one of the pulleys being driven by a motor.

Lowest energy consumption and minimal wear and tear of the device according to the invention for opening tubular bag bodies are achieved if the drive of the conveying device and the drive device for moving the slide along the orbit are continuously running drives. The orbit for the slides can be defined by a rail on which the respective slides are slidably mounted. Advantageously, a device for slidably mounting the slide on the rail comprises a socket and a shaft slidable therein, either the socket or the shaft engaging by means of rollers or sliding surfaces in the rail and the shaft or the socket being connected to the slide.

While in conventional systems the slider usually consists of a plate that has to be exchanged as a whole each time the sack body sizes are changed, in a further development of the present device for opening sack bodies it is provided that each slider has a crossbeam and at least two attached to it, preferably at a distance to each other and length adjustable slide fingers includes. Depending on the desired sack base dimensions, these are set at a distance from one another (which defines the longitudinal edge of the base) and their length (which defines the width edge of the base together with the slide stroke). An exchange of the slide when changing the bag body size is therefore unnecessary.

As mentioned, according to the prior art, the slide and the bag body lie in one plane. When the sack body is opened by the slide, this leads to the undesirable effect that up to four in the folded state of the sack body

Material layers on top of each other! but there is only one location in other areas. This difference in thickness creates the further processing of

Bag body considerable problems. The present invention also offers a solution to this problem in that, according to one embodiment, the sack bodies are arranged in transverse fold on the sack body conveying device, which differs from that

Transverse folding line in the direction of the slider extending bag body portion is substantially in the plane of the reciprocating movement of the slider, and extending from the transverse folding line away from the slider bag body portion in a plane which is an angle, preferably an approximately right angle, with the level which includes the slide movement. As a result of this measure, a maximum of two material layers of the bag body lie one above the other after the folding.

The invention will now be described by way of example with reference to the drawings, in which FIG. 1 shows an embodiment of the device according to the invention for opening tubular bag bodies schematically in a side view and FIG. 2 shows the same device schematically in a top view, the conveyor belt with the bag bodies not being shown in the latter figure is.

Unless expressly stated otherwise, the following description refers simultaneously to FIG. 1 and FIG. The device according to the invention shown for opening tubular bag bodies has a conveyor belt 1, on the upper side of which tubular bodies 2, 2 a are held by a suitable means, such as a vacuum. The conveyor belt moves continuously and at a constant speed in the direction of arrow A. The bag bodies lie horizontally on the conveyor belt with the exception of one end region that is to be formed into the bag bottom, with their long axes pointing transversely to the transport direction A. The named end region of each sack body 2, 2a is bent vertically downward over a long edge 1a of the conveyor belt 1 and hangs over one of six sliders, generally designated 3. (In Fig. 1 only two sliders are shown for reasons of clarity)

The sliders 3 are slidably attached to a rail 4 which has two opposite straight sections 4a, 4b which are connected at their ends by two semicircular sections 4c, 4d. The sliding attachment of each slide 3 to the rail 4 takes place by means of four rollers 31, two of which engage in one of two opposite long edges of the rail 4. The rollers 31 are rotatably attached to the end face of a slide head 33, from the opposite end of which a shaft 34 extends downward. A bush 35 is slidably mounted on the shaft 34. This bush 35 carries a guide track Form of a horizontal U-profile 38 with open ends and a crossbar 39, from which slide fingers 36, 37 extend in the form of elongated, narrow plates at a distance from one another perpendicularly upwards. The slide fingers can be adjustably attached to the crossbar 39. The U-profile 38 and the crossbar 39 can also form an integral unit.

Below the semicircular sections 4c, 4d of the rail 4, two wheels 5,6 with vertical axes of rotation 5a, 6a are arranged concentrically thereto. At least one of the wheels is driven by a motor, not shown. The two wheels 5, 6 are wrapped in a chain 7, which is rotated in the direction of arrow C. The speed of the chain 7 is the same as that of the conveyor belt 1. The chain 7 engages firmly with an extension 32 of each slider and thus pulls the respective slider 3 with it. The sliders 3 are evenly spaced around the chain 7 and thus also around the rail 4, the distance between two sliders corresponding to that of the distance between two sack bodies on the conveyor belt. Suitable control also ensures that each slider is opposite a bag body during its movement along section 4a of the rail 4 on the conveyor belt 1.

In order to effect the movement of the bush 35 and thus the slide finger 36, 37 along the shaft 34, a separate drive is provided. This consists of a chain 8 rotating around four wheels 10, 1, 12, 13 with horizontal axes of rotation. At least one of the four wheels is driven, so that the chain 8 is moved in the direction of arrow B at a speed which is greater than that of the conveyor belt 1 and the chain 7. The four wheels 10, 1, 12, 13 and thus the chain 8 lie in a vertical plane approximately below the longitudinal edge 1a of the conveyor belt. The wheels 10, 1, 12, 13 divide the revolving chain 8 into a first, obliquely upwardly inclined section 8a, a second, obliquely downwardly inclined second section 8b, a parallel to the longitudinal edge 1a of the conveyor belt 1, but from its facing, third section 8c, and finally a fourth section 8d, the runs parallel to the third section and adjacent to the conveyor belt 1. The chain 8 has three cams 9 at regular intervals.

The function of the device will now be explained.

First, the conveyor belt 1 and the chains 7 and 8 are set in motion. Sack bodies are fed at predetermined intervals on the conveyor belt, and in coordination with this, the sliders 3 move horizontally around the rail 4. When a first slider reaches a position near the wheel 1 3, a cam 9 of the chain 8 engages in the front one open end of the U-profile 38 of the slide. This happens, although the absolute speed of the chain 8 is greater than that of the chain 7, but the speed component of the chain 8 parallel to the chain 7 in the inclined circulating section 8a is smaller than the absolute speed of the chain 7. This means that the cam 9 in section 8a is caught and overtaken by the slider 3, which is why the cam first enters the front end of the U-profile 38 of the slider and then travels backwards in it, but at the same time lifts the slider due to the obliquely upward course of the circulation section 8a. The slide fingers thus come into engagement in the open end of the bag body facing them and fold the front wall of the bag body - based on the plane of the drawing - along a through a ruler 1 5, which is above the longitudinal edge 1 a of the conveyor belt and thus also above the Bag body is located, defined fold line upwards. The rear wall of the bag body can be sucked in completely or in sections by a vacuum belt lying behind it and moving with respect to the drawing level, in order not to be pulled along during the folding process.

Before the cam 9 can exit the U-profile 38 at the rear end, it has reached the wheel 10 and begins to move along the section 8d. The slide fingers 36, 37 have now reached their highest position and maintain this as long as the cam 9 is in section 8d. The end of the bag body has a hexagonal folding configuration, as shown on the bag body 2a. In In this condition, a valve sheet can be glued or welded on, if necessary. On the section 8d parallel to the conveyor belt, the cam is again faster than the rotary movement of the slide and therefore moves forward again in the U-profile 38.

During the movement of the cam in section 8d, a next slide already reaches the position on wheel 13 and engages with another cam 9 of chain 8. The movement of this second and all subsequent sliders takes place as described above and requires no further explanation.

Returning to the movement of the first slider, the cam 9 reaches the wheel 11 before it can exit the U-profile of the slider at the front end and goes obliquely downwards, i.e. away from the bag body transport device, directional movement and thereby also pulls down the slide, the slide fingers of which finally disengage from the bag body. At the turn of the chain 8 on wheel 12, the cam 9 finally leaves the U-profile 38 through its rear open end and moves along the section 8c back to wheel 13 in order to engage another slide 3 there. The first slide 3 moves a little further straight after it has come out of engagement with the cam 9, in order then to turn on the rail section 4c.

It is also possible to omit one of the two wheels 10 or 11 and thus the revolving section 8d of the chain 8 if it is considered sufficient that the slide fingers are withdrawn immediately after reaching their maximum extended position without remaining in the extended position .

Claims

Claims:

1 . Device for opening tubular sack bodies open at least at one end, with at least one slider which can be inserted between sack body walls into an open end of a sack body in order to at least partially fold over at least one end region of a sack body wall, the at least one slider being provided by a device for the rear movement of a respective slide into and out of the bag body end to be opened, characterized in that the device (8-13) for the back and forth movement of a respective slide (3) has at least one driven along a predetermined path ( 8) comprises movable cam (9) which engages on the slide (3) to move it back and forth.

2. Device for opening tubular bag bodies according to claim 1, characterized in that the at least one cam (9) on a driven

A chain (8) or a belt is mounted, which rotates around wheels (10, 1, 12, 13) or pulleys, with a first, rotating section (8a) approaching the bag body, a second, through the wheels , Circulating section (8b) leading away from the bag body and a third circulating section (8c), which forms a cam return section, are defined.

3. Device for opening tubular bag bodies according to claim 2, characterized in that between the first (8a) and second (8b) circulation section, a fourth circulation section (8d) is further provided, which has a substantially constant distance from the bag body end to be opened.

4. Device for opening tubular bag bodies according to claim 2 or 3, characterized in that the positions of at least one of the wheels (10, 1, 12, 13) or pulleys of the device for the reciprocation of a respective slide are adjustable.

5. Device for opening tubular bag bodies according to one of the preceding claims, characterized in that each slide has a guide track (38) for sliding engagement with the cams (9).

6. Device for opening tubular bag bodies according to claim 5, characterized in that the guide track of each slide for sliding engagement with the cams (9) is a fixed to the slide U-profile (38) with open ends, the longitudinal axis at right angles to the direction the reciprocating movement of the slide is arranged.

7. Device for opening tubular bag bodies according to one of claims 2 to 6, characterized in that further a conveying device (1) for transporting the bag body and a drive device (5,6,7) for moving the slide (3) along an orbit (4) are provided, the drive of the conveyor device (1) and the drive device (5, 6, 7) for moving the slide along the orbit being synchronized with one another, so that in operation the transport speed (arrow A) of the bag body on the conveyor device is substantially equal to the speed (arrow C) of the slide (3) along the orbit.

8. A device for opening tubular bag bodies according to claim 7, characterized in that the speed on the chain (8) or the belt with the cams (9) is set so that it is higher than that of the slide around the orbit ( 4).

9. A device for opening tubular bag bodies according to claim 7 or 8, characterized in that the drive device for moving the slider along the orbit comprises a chain (7) rotating around gear wheels (5, 6) or a belt rotating around pulleys, the Chain or strap with connected to the slide and at least one of the gears or one of the pulleys is driven by a motor.

10. Device for opening tubular bag bodies according to one of claims 7 to 9, characterized in that the drive of the conveyor device (1) and the drive device (5,6,7) for moving the slide along the orbit are continuously running drives.

1 1. Device for opening tubular bag bodies according to one of claims 7 to 10, characterized in that a plurality of slides (3) is provided, which are distributed along the orbit (4) at uniform intervals.

12. Device for opening tubular bag bodies according to one of claims 7 to 1 1, characterized in that the orbit by a rail

(4) is defined, on which the respective slide (3) are slidably mounted.

13. A device for opening tubular bag bodies according to claim 12, characterized in that a device for slidably mounting the slide on the rail (4) comprises a socket (35) and a shaft (34) slidable therein, one of the socket and the shaft engages in the rail (4) by means of rollers (31) or sliding surfaces and the other is connected to the slide.

14. Device for opening tubular bag bodies according to one of the preceding claims, characterized in that each slide (3) has one

Has crossbars (39) and at least two slide fingers (36, 37) fastened to them, preferably adjustable at a distance from one another and in length.

15. Device for opening tubular sack bodies according to one of claims 7 to 14, characterized in that the sack body in transverse folding of the sack body conveyor, the sack body portion extending from the transverse fold line toward the slider being substantially in the plane of reciprocating movement of the slider, and the sack body portion extending away from the transverse fold line away from the slider being in a plane that is one Includes angle, preferably an approximately right angle, with the plane of the reciprocating movement of the slide.