EP1035966B1 - Device for separating lines of material which are arranged on top of each other - Google Patents

Abstract

The invention relates to a device for separating two lines of material which are arranged on top of each other. The lines of material are to be separated whilst they are being transported on a conveying device, the first of the lines of material being detachably fixed to the conveying device. The inventive device comprises a suction device (8, 9), which is moveable in relation to the second line of material and by which means it is able to temporarily draw the second material by suction and separate it from the first line of material. The device also has two cranks (10, 13) which are set apart and which each rotate about a first pivot pin (10a, 13a) and are each rotationally connected to the suction device (8) by a second pivot pin (10b,13b). The inventive device is characterised by a drive device with a peripheral engaging element which is connected to an engaging element configured on one of the cranks. The paths of revolution of the drive device engaging element and the crank engaging element do not coincide and are non-parallel and the engaging elements engage with each other in such a way that they can be displaced in relation to each other.

Description

The invention relates to a device for separating two material webs lying one above the other, in particular those of sack bodies, or individual areas thereof, while they are being transported on a conveying device, the first of the material webs being releasably fixed to the conveying device, in accordance with the preamble of Claim 1.

In general, there is one in the manufacture of sacks from any materials Production step in it, the pre-cut, tubular bag body in one Fold the end to form a bottom. To do this, slide a slider into an open one End inserted between the walls of the flat-lying sack body, the Movement of the slide, possibly in cooperation with outside the Sack body beams, the desired folding of the side walls of the Bag body causes. Since the sack body lies flat on top of one another Sliders are transported there, one is faced with the problem that the edges the open ends of the bag body or even entire edge areas thereof stick to each other and therefore not the slider between the sack body walls can be introduced. This effect can be caused by electrostatic charging Material webs, due to the presence of adhesive residues, in plastic materials by welding the edges of the sack body together in the course of the previous one Cutting the bag body with a hot wire, or with airtight materials generally occur due to the material lying flat against one another. In any case leads the adhesion of the edges of the ends of the bag body that a Production step must be provided through which the end regions of the Material webs are separated from each other, after which the slide between the To be able to introduce material webs. Furthermore, it is desirable to do this Carry out the separation process during the continuous transport of the bag body, in order not to have to accept a limitation in production speed. In addition, all moving device parts involved in the separation process should be shown in continuous motion, i.e. accelerations as low as possible and Experienced delays due to premature wear and high necessary Avoid driving energy. From the point of view of wear and energy consumption the device would be ideally rotating parts.

The problems addressed can be solved with a device such as is known, for example, from DE-A-1 511 021. This includes a suction bar rotating in the machine cycle, which is pivotally connected to levers by means of two bolts, which in turn are not rotatably connected to gearwheels by bolts located thereon. Another rotatable gearwheel is in engagement with the gearwheels and transmits a driving force to the former gearwheels. The suction bar thus moves parallel to the transport direction of hose sections. In order to linearize the speed of the suction bar, it is proposed to drive the drive gear in turn via an elliptical gear mechanism, not shown. Another drive device is neither disclosed nor suggested.

A disadvantage of the device disclosed in DE-A-1 511 021 is the use of a device Elliptical gear, which is expensive to manufacture on the one hand and none on the other complete linearization of the squeegee movement in unison with bag bodies transported past, but just a more or less good one Approach enables. The better the approximation to a linear uniform Squeegee movement, i.e. the more pronounced the gear ellipses are, the larger are also the inevitable friction losses.

From EP 0 770 476 a device for separating bag bodies during their transport on a conveyor device is known, as set forth by the features of the preamble of the present claim 1. Compared to the subject of DE-A-1 511 021, the device according to EP 0 770 476 is improved in that, instead of an elliptical gear, it has a drive device with an engaging element rotating along a predetermined path, which is connected to an engaging element formed on one of the cranks is, wherein the orbits of the engaging element of the drive device and the engaging element of the crank do not coincide and are not parallel, and the engaging elements mesh with one another in a displaceable manner with respect to one another. The linearization of the squeegee movement in harmony with the sack bodies being transported past is considerably improved as a result, but is still not optimal.

The present invention, as set out in the characterizing part of claim 1, offers a solution to the disadvantages of the prior art which enables a complete linearization of the suction beam movement in harmony with the bag bodies being transported past, with high economy.

The driving device with the engagement element provided thereon is formed according to the invention so that the engagement member is attached to a chain or a belt, or the circulating around at least two wheels, of which at least one is driven. The chain or belt defines the orbit of the engagement element of the drive device. The chain or belt preferably has a run parallel to the conveying direction of the material webs and the chain or belt speed is equal to the conveying speed of the material webs. As long as the engaging element moves in the parallel run, complete linearization of the speed component of the suction device parallel to the conveying direction of the material webs can thereby be achieved. The engagement element advantageously has a channel which is normal to the chain or belt and into which a cam or roller engages as an engagement element of a crank.

Due to the rotatable connection of the suction device with the two cranks, the swivel joints involved spanning a parallelogram, the suction device executes a rotational movement in the course of which it approaches the second material web or touches and sucks it and then moves back again, the sucked second material web is pulled and thereby stands out from the first material web. The rotational movement of the suction device is favorable in that it has both a speed component parallel to the conveying direction of the material webs in order to carry the suction device along with the movement of the material webs during the separation process, and also a speed component normal to the conveying device in order to pull the second material web away from the first. However, with a uniform rotational movement, the course of both speed components would be sinusoidal, as a result of which the parallel speed component of the suction device would only be the same as the conveying speed of the material webs at a certain crank angle. Consequently, the second material web would not only be lifted from the first, but would also be displaced, which would have a disadvantageous effect in subsequent processing steps of the material webs. A linearization of the course of the parallel speed component of the suction device is therefore necessary, as disclosed in claim 1, wherein the parallel speed of the suction device can be matched with the conveying speed of the material webs by appropriately designing the orbits of the engaging elements and the speed of the drive device for a large crank angle range.

In embodiments of the invention, the cranks as crank disks or with Be crank arms.

To the displacements that the engagement elements with respect to each other during their Experience circulation, record, is provided according to the invention, either that Engagement element of the drive device or the engagement element of the crank with a Cam that is in a slot or an elongated hole or a channel of the other Intervening elements engages to train. Alternatively, a telescopic arm can also be used be provided, the articulated with the drive device and the crank connected is.

It is preferred to communicate the aspirator with a vacuum source to let. However, since the suction device is only in during part of its rotation Operation must be, in this case it turns out to be favorable if the communication depending on the angular position of one of the suction device connected cranks can be interrupted.

This is a useful further development of the device according to the invention characterized in that a connecting line of the suction device with vacuum-tight a through hole is connected in a disc, the disc is rotatable together with one of the cranks, and on the opposite Surface of the disc is a fixed one connected to the vacuum source Vacuum bar is essentially vacuum-tight, the vacuum bar one has the circular arc-shaped mouth opening facing the pane surface coincides with the circular path which, when the disc rotates from the mouth of the Through hole is described. This version can be mentioned as the Serve a crank disc.

A preferred embodiment of the suction device comprises a bar an inner channel for connection to a vacuum source and a large number of Inner channel extending outlet openings, to the appropriate suction cups are connected.

In itself, it is sufficient if only one of the cranks is driven, with which the Suction device is connected because the driving torque through the suction device to the second crank. However, it can happen that the Cranks must be set in motion from a dead center. The dead center is thereby the crank position in which the sides of the through the hinge points of the The parallelogram cranks spanned together to form a line. In this Position, there could probably be no cranking. To do this avoid, it is useful to move the two cranks to synchronous movement To connect belt or chain gear.

The invention will now be explained in greater detail on the basis of exemplary embodiments, with FIG. 1 schematically showing a first embodiment of the device that is partially outside the scope of the invention in a side view and FIG. 2 showing the same device in a top view. 3 and 4 show details of this device, and FIG. 5 is a diagram which shows the course of the parallel speed component of the rotating suction device of this device plotted against the crank angle. 6 shows an embodiment of the device according to the invention schematically in side view and FIG. 7 shows the same device in plan view. 8 and 9 show details of this embodiment of the device according to the invention and FIG. 10 is a diagram which shows the course of the parallel speed component of the rotating suction device of the device according to the invention plotted against the crank angle.

Referring first to FIG. 1 and FIG. 2, a conveyor device can be seen in FIG Form of a conveyor belt 1 that moves in the direction of arrow A. tubular Bag body 2.2a lie with its longitudinal axis transverse to the conveying direction A on the Conveyor belt, the majority of the bag body horizontally on the Conveyor belt lies and only one end area, the material webs of which are separated from one another are to depend on the longitudinal edge of the conveyor belt 1 down. The Conveyor also has a second conveyor belt 3, which is vertically below of the conveyor belt 1 is arranged in alignment with its longitudinal edge and with same speed as the conveyor belt 1 rotates around 4.5. The conveyor belt 3 is designed as a perforated conveyor belt with a plurality of holes 3a, behind which a Vacuum bar 6 is arranged so that the conveyor belt 3 facing Material web of the bag body 2 over the length of the vacuum bar 6 against the Surface of the conveyor belt 3 is sucked in and during its continuous Transport is fixed to it. To ensure that this first web of material Bag body is actually sucked from the conveyor belt 3 is an obliquely downward running guide rod 7 is provided, which the respective depending part of the Bag body 2a directs towards the conveyor belt 3.

On the side facing away from the conveyor belt 3, the side hanging down from the conveyor belt 1 Sack body parts is a suction device in the design according to the invention arranged. This suction device includes a parallel to the hanging part the bag body arranged bar 8, on which a number of suction cups 9 on the the side of the beam facing the bag body are attached. The suction cups communicate with a vacuum channel 8a inside the beam 8, the Vacuum channel 8a is indirectly connected to a vacuum source, not shown. The beam 8 is on the one hand via a swivel joint 10b with a crank arm 10 connected, which rotates about a pivot bearing 10a, and also via a pivot joint 13b connected to a crank disc 13 which rotates about a pivot bearing 13a.

A pulley 11 is rigid with the axis of the rotary bearing 10a Crank arm 10 connected. Another pulley 14 is also coaxial and rigid connected to the crank disc 13. The two pulleys 11 and 14 point the same diameter and are coupled to each other via a belt 15. This belt transmission serves the two cranks 10, 13 synchronously with one another move and prevent accidental stoppage of the cranks on one Dead center is no longer the crank 13 which moves with the connection to the beam 8 can be set in motion by the driven crank 10.

The cranks 10, 13 with the bar 8 meet the following dimensioning requirements: the swivel joints 10a, 13a about which the crank arm 10 or the crank disk 13 rotate, have the same distance from each other as the pivot joints 10b, 13b when they are with the bar 8 are connected; the distance between the pivots 10a, 10b of the Crank arm is equal to the distance between the pivots 13a, 13b Crank disk 13. Thus, the four pivot joints mentioned form the corner points of one Parallelogram. This parallelogram arrangement of the cranks with the bar 8 causes the bar to be caused by a crank drive Rotational movement always maintains a position parallel to the material web, the Distance of the arrangement to the material web is set so that the suction cups 9 at their closest approach to the material web touch them.

Now also referring to FIG. 4, which is an enlarged detail from FIG represents the circular speed of the swivel joint 10b as a vector v, which is divided into a speed component vp which is parallel to the direction of conveyance of the Material webs, and a speed component vn, which is normal to the The conveying direction of the material webs can be disassembled. These speed vectors also apply to bar 8. Both speed components vp, vn would be at uniform circular velocity, i.e. with uniform rotation of the crank 10 µm change the pivot bearing 10a, sinusoidally. However, this is undesirable, as a preliminary has already been established. Rather, the goal is the parallel Velocity component vp around the range of a curve angle α of 90 °, that is the Area of the greatest approach of the beam 8 to the material web as possible linearize. This is achieved in that the crank 10 by an eccentric element is driven, as in the following with particular reference to FIGS. 2 and 3 is explained. Such a drive is also known from EP 0 770 476 A2 known.

A drive device in the form of a toothed disc 16 with an axis of rotation 16a axially parallel to the axis of rotation of the pivot joint 10a of the crank 10, but by one Eccentric distance e is offset, is coupled via a chain 17 to a pinion 18, which is connected to the output shaft 19 of a motor, not shown. At hers The underside has the toothed disc 16 two approximately radially and parallel to each other arranged guide plates 16b, 16b, which define a channel therebetween engages with a cam or roller 10d. The roll 10d is one at the end Extension 10c of the crank arm 10 is arranged, the extension 10c the extension represents the crank arm 10 beyond the pivot bearing 10a. Because the axes of rotation of the Toothed washer 16 and the crank 10 are offset from each other by the distance e, the Crank 10 does not move uniformly with uniform rotation of toothed disk 16, but depending on the eccentricity e and the distance b (see Fig.4) from Roller 10d to pivot bearing 10a accelerated and decelerated, roller 10d in the channel slides between the guide plates 16b, 16b to move the point of engagement balance between roller and guide plates.

The by the eccentric arrangement of the toothed disc 16 and that of it driven crank 10 achieved linearization of the parallel speed component vp can be seen from the diagram in Fig. 5. It can be seen that in the area of a Crank angle α between 45 ° and 135 ° a good linearization was achieved. The speed of rotation of the toothed disc 16 is preferably set in such a way that that at α = 90 ° vp is equal to the conveying speed of the material webs hardly any slip occurs between the suction cups and the material web.

In Figure 3, 29 denotes a support plate of the machine body on which the Drehgeienk 10a is mounted. Furthermore, to clarify the rotating arrangement in Fig.1 and Fig.2 the crank 10 with bars 8 in a crank angle α = 90 ° in full Lines and additionally at α = 45 ° in phantom lines (see reference numerals 8 ', 10') shown. Likewise, the crank 10 with bars 8 in a crank angle α = in FIG 90 ° in full lines and additionally at α = 135 ° in phantom lines. The Distance a in FIG. 4 is the greatest distance between the center of the roller 10 and the center the driving toothed pulley 16 and fulfills the equation a = b + e.

The suction cups 9 on the bar 8 could be permanently connected to a vacuum source. However, it is considered more convenient if the vacuum source approaches the Suction cups on the material web relatively shortly before the suction cups touch the Material web is switched through to suck the material web onto the suction cups, and stays on while the suction cups move past the point Remove as close as possible from the conveyor of the material webs while doing so pull the web of material they sucked in while simultaneously pulling the other Material web of the bag body is sucked on the conveyor belt 3. The vacuum source will finally switched off again when the distance between the two Material webs is considered sufficient. To accomplish this is provided that the crank disc 13 at its junction with the swivel 13b has an axially parallel through hole 13e, which is also in the swivel joint 13b continues, the vacuum channel 8a of the beam 8 with this through hole communicated. Is on the opposite surface 13 c of the crank disc 13 in a vacuum-tight manner to a vacuum bar 20 which is fixedly mounted, wherein the vacuum bar has a circular arc shape facing the surface of the pane Muzzle opening 20a, which coincides with the circular path, which when rotating the disc 13 from the mouth of the through hole (13e) is described. The Mouth opening 20a communicates with a connecting piece 20b to which one does not shown vacuum source can be connected. Thus the vacuum channel 8a of the beam 8 only over a precisely defined angular range Crank disc rotation connected to the vacuum source.

FIGS. 6 to 9 show an embodiment of the invention Device shown. This only differs from the first embodiment by another drive device with which the crank 30 (corresponds to crank 10 of the first embodiment) is driven. Therefore, regarding the same Components of the device use the same reference numerals and it is referred to the above Described description and omitted another detailed explanation.

The drive device of the second embodiment is no longer an eccentric disc, but comprises two double gears 31, 33, over which a double chain 32 rotates. The axis of rotation of the double gear 33 is rigid with a further gear 34 connected, via a chain 35 from the pinion of a motor, not shown is driven. On the double chain 32, an engagement element 36 is running attached, which consists of a U-profile, the longitudinal axis of which is normal to the double chain 32 stands. The legs of the U-profile define a channel in which a roller 30d is attached as an engagement element at the end of the crank 30, in a slidable manner is included. The orbit of the roller 30d when the crank 30 rotates is 30a designated. The double chain 32 forms between the double toothed wheels 31, 33 a strand parallel to the conveying direction of the material webs on both sides, whereby the double chain is driven at such a speed that in one parallel run the engagement element 36 moves at the same speed as the material webs on the conveyor belt 1. With special reference to Fig. 9 it can be seen that the engagement element 36 is the beginning of the first parallel Double chain center reached when the crank angle α is approximately 45 °. The At this time, the engaging element has half encircled the double gear 33. From At this time, the crank 30, the roller 30d is engaged with the Engagement element 36 is located with a parallel to the material web conveying direction Speed component vp driven, which corresponds exactly to the conveying speed. This parallel speed component is maintained until the Engaging element reaches the double gear 31, i.e. the end of this parallel Double chain center reached. The crank 30 has about one at this time Kurpel angle of 135 °. From this point in time, the engagement element 36 starts from one Translational movement into a rotational movement about the double pinion 31, which changes the size and ultimately the sign of the parallel Speed portion of the crank 30 changes to which the changed movement of the Engagement elements is transferred.

From the diagram of Fig. 10 it can be seen that the parallel guidance of the Engagement elements over a crank angle range of approximately 45 ° to 135 ° complete linearization of the parallel speed component vp, that of the bar 8 experienced was achieved.

Claims (10)

1. A device for separating two material webs lying on top of each other, preferably those of bag bodies (2, 2a), or individual portions thereof, while they are being transported on a conveying means (1), the first of the material webs being detachably fixed to the conveying means, the device comprising:

   a suction means (8,9) movable with respect to the second material web for temporarily sucking the second material web and separating it from the first material web;

   two cranks (10,13) spaced from each other, each having a first rotatable joint (10a, 13a) for rotating the crank around this rotatable joint, and a second rotatable joint (10b, 13b) to which the suction means is rotatably connected,

   both cranks having the same distance between their respective first (10a, 13a) and second (10b, 13b) rotatable joints, and the distance between the first (10a, 13a) rotatable joints of both cranks being equal to the distance between the second (10b, 13b) rotatable joints of both cranks as they are connected to the suction means, so that the rotatable joints define the comers of a parallelogram,

   a drive means (16;31-34) having an engagement element (16b;36) orbiting along a predetermined path and connected to an engagement element (10d;30d) formed at one of the cranks, the orbit paths of the engagement element (16b;36) of the drive means and of the engagement element (10d; 30d) of the crank not coinciding and not being parallel, and the engagement elements engaging displaceably with respect to each other, characterized in that the engagement element (36) of the drive means is attached to a chain (32) or a belt, which encircles at least two wheels (31, 33), at least one (33) of which is driven.
2. The device according to claim 1, characterized in that the chain (32) or belt has a run in parallel with the conveying direction of the material webs (2) and in that the speed of the chain or belt is equal to the conveying speed of the material webs (2).
3. The device according to claim 1 or 2, characterized in that the engagement element (36) of the drive means has a channel at right angles with the chain or belt, which channel is engaged by a cam or roller (30d) of a crank (30).
4. The device according to any of the preceding claims, characterized in that the two cranks (10, 13) are connected to each other for synchronous movement by a belt or chain gear (11,14, 15).
5. The device according to one of claims 1 to 4, characterized in that at least one of the cranks is a crank disk (13).
6. The device according to one of claims 1 to 4, characterized in that at least one of the cranks is a crank arm (10).
7. The device according to any of the preceding claims, characterized in that one of the engagement element (16b; 36) of the drive means and the engagement element (10d; 30d) of the crank (10; 30) comprises a cam, and the other comprises a slot, an oblong hole, a channel or at least one guiding rail or a guide plate (16b).
8. The device according to any of the preceding claims, characterized in that the suction means (8, 9) communicates with a vacuum source, the communication preferably being interruptable as a function of the angular position of one of the cranks connected to the suction means.
9. The device according to claim 8, characterized in that a supply pipe of the suction means is vacuum-tightly connected to a through hole (13e) in a disk, preferably a crank disk (13), and in that a stationary vacuum bar (20) connected to the vacuum source is substantially vacuum-tightly contiguous with the opposing surface (13c) of the disk, the vacuum bar (20) having a mouth opening (20a) taking the form of a circular arc and facing towards the disk surface (13c), which opening coincides with the circular path described by the mouth of the through hole (13e) when the disk is rotated.
10. The device according to any of the preceding claims, characterized in that the suction means comprises a bar (8) having an internal channel (8a) connectable to a vacuum source as well as a plurality of exit openings extending therefrom, to which preferably suction cups (9) are connected.

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