EP0695687A2 - Device for strapping goods - Google Patents

Abstract

The strap is moved by an in-feed through channels in a frame inside which the material to be strapped is placed. The top traverse of the frame, in which the bundle is placed, is lowered onto the material to be strapped to compress it. The system which connects the ends of the strap is mounted on top of the traverse. Because the path, over which the strap is moved, is long, an additional set of drive rollers is provided. The rollers move the strap by friction. The axes (40,41) of the rollers (38,39) lie either side of the strip in a plane at right angles to the plane of the strap. One of the rollers is spring-loaded against the side of the strap and can be swung clear from the strap.

Description

The invention relates to a device for strapping packaged goods according to the preamble of claim 1.

In strapping machines of the type from which the invention is based, the strapping means, in modern machines almost exclusively weldable, thermoplastic plastic band, is shot in by means of a conveying device by means of a conveying device by means of a conveying device, by means of a conveying device, surrounding the packaged goods provided on a packing table or roller conveyor. Depending on the type of machine, this is done either near the strapping stock or in the area of the strapping closure unit, these conveying devices generally consisting of roller-shaped pairs of rollers with at least one driven roller, with the strapping means held between the rollers being advanced. As the amount of strapping is increased, the free, pushed strapping section increases in length and the security of the strapping circulation within the strapping guide frame is correspondingly increasingly dependent on the quality of the strap, in particular on its buckling stiffness. On the other hand, strapping tool guide frames generally have four rounded corner areas, which, however, can also offer particular resistance to the leading strapping end, even if they are carefully manufactured. In the case of large machines, particularly in the case of so-called 'packaging presses', the length of the strapping guide frame into which the strapping agent is loaded is must be 12 meters and more. It can be seen from this that the strapping of strapping material into a strapping guide frame can be problematic and can lead to considerable malfunctions.

An intermediate conveyor has therefore been arranged in addition to the conveyor device assigned to the strapping agent supply or the sealing assembly, at a position within the strapping device guide frame at which the strapping device transported by the conveyor device has covered approximately 2/3 of its total circulation path.

In a strapping device known from public prior use, the two rollers of this additional conveyor consist of rollers, the axes of which are aligned transversely to the orbit of the strapping means and one roller behind and the other roller in front of the strapping means acts on the latter. 'Behind the strap' is synonymous with the side of the strap pointing to the outside of the strap guide frame. The roller arranged here can rotate about a stationary axis, while the roller engaging on the inside of the strapping guide frame on the strapping means is provided in such a way that it is attached to a pivotable arm which can be pivoted out so far by means of a lifting magnet that the strapping means , if it comes free from the strapping guide frame to be tightened against the packaged goods ready, cannot get caught on the lifted roller.

This control of the ventable role of the additional conveyor by means of a lifting magnet and its required control is of course complex. It is also problematic to bring the strapping means supplied to the additional conveyor by the (first) conveyor device between the two rollers of the pair of rollers of the additional conveyor without the leading end getting caught in the nip. On the other hand, it is of course required that the rollers of the additional conveyor can reliably grip the incoming strapping end. In order to master these contradictory objectives, in the previously known additional conveyor, the stationary rotating roller is provided in a complex manner with sections which are alternately smooth in the circumferential direction of their jacket, smaller in diameter and corrugated, larger in diameter. The smaller diameter sections form an insertion gap for the entry of the strapping between the two rollers, while the roughened sections are used for transporting the strapping. The ventilated, opposite second roller is a plastic roller with a smooth, slightly compressible jacket. The design, in particular of the metallic roller, is very complex and leads to an inhomogeneous transport of the strapping means, which manifests itself in a disadvantageous 'picking'.

If the axes of the two rollers of the pair of rollers of the additional conveyor are not exactly parallel to one another, there is also still use of the usual thermoplastic plastic belts with flat rectangular ones Cross-section as strapping means the risk that the strapping is compressed in a wedge shape, which manifests itself in that coercive forces are exerted on the belt section advanced by the additional conveyor, which can lead to an arcuate course of the leading strapping.

Proceeding from this, the invention has for its object to provide a device of the type outlined in the preamble of claim 1, in which the additional conveyor is designed considerably simpler. Another aspect of the invention relates to a simplified possibility for venting at least one roller of the additional conveyor roller pair. Furthermore, the forces exerted by the rollers of the additional conveyor on the strapping means should be as low as possible, but in no case should they lead to malfunctions.

The invention solves the problem in connection with the features of the preamble of claim 1 by its characterizing features. Thereafter, it is provided that the axes of the rollers laterally next to the orbit penetrate the plane defined by this and the at least one ventable roller can be swung out of the strapping movement path to the side against the action of a spring loading it against the strapping means and thus against the second roller .

As in the prior art, the axes of the rollers of the pair of additional conveyor rollers also lie transversely, in particular perpendicularly, in the additional conveyor of the invention. to the orbit of the strapping tool. However, they are not, as in the prior art, in planes parallel to the orbit, but penetrate the plane defined by the orbit or the strapping means. As a result, in the case of ventilation of at least one roll need not be pivoted around a large angular path of up to 90 ^o the role in question, but only a very small distance. This is because the roller does not engage the strapping means in front of and behind the orbit, but rather affects the orbit on the long sides of the strapping means. However, if it is not necessary to pivot the ventable roll far, according to the knowledge of the invention, the release of the roll can be left to the strapping pull in a very simplified manner, if the strapping tool is tightened as a result of reversing the drive of the conveyor from the Strapping guide frame is released to be tightly tightened around the package. The pair of rollers now acting on both narrow sides and not on the front and the back of the strapping means is no longer able to disadvantageously deform the strapping means. In addition, it has surprisingly been found that the very small-area attack of the rollers on the long sides of the strapping means is completely sufficient to push the strapping means securely forward, but on the other hand surprisingly low forces are required, which therefore do not force the strapping means to buckle.

Fig. 1

eine schematische Ansicht einer als 'Verpackungspresse' ausgestatteten Umreifungsmaschine,

Fig. 2

die wesentlichen Teile eines Zusatzförderers entsprechend der Erfindung in der Umreifungsmittel-Förderphase,

Fig. 3

eine Stirnansicht in Richtung des Ansichtspfeiles III der Fig. 2,

Fig. 4

eine der Fig. 2 entsprechende Darstellung, wobei nun die Rollen des Zusatzförderers zur Freigabe des Umreifungsmittels gelüftet sind,

Fig. 5

eine der Fig. 3 entsprechende Stirnansicht auf Fig. 4,

Fig. 6 bis 9

im wesentlichen den Fig. 2 bis 5 entsprechende Darstellung, wobei im Bereich des Zusatzförderers zusätzliche, das Umreifungsmittel während des Förderns rückhaltende Klappen vorgesehen sind, und

Fig. 10 und 11

Darstellungen zur Erläuterung des Standes der Technik.

Further refinements of the invention as well as expedient and advantageous features are in the subclaims indicated and also result from the following description of the invention using an exemplary embodiment with reference to the drawings. In it show:

Fig. 1

1 shows a schematic view of a strapping machine equipped as a 'packaging press',

Fig. 2

the essential parts of an additional conveyor according to the invention in the strapping conveying phase,

Fig. 3

3 shows an end view in the direction of the arrow III of FIG. 2,

Fig. 4

2 shows a representation corresponding to FIG. 2, the rollers of the additional conveyor now being released to release the strapping means,

Fig. 5

3 shows an end view corresponding to FIG. 4 on FIG. 4,

6 to 9

2 to 5 essentially corresponding representation, wherein additional flaps are provided in the region of the additional conveyor, retaining the strapping means during conveying, and

10 and 11

Representations to explain the prior art.

The device designated overall by 10 in FIG. 1 serves for strapping particularly compressible packaged goods 11 such as corrugated cardboard layers or the like. First of all comprises a supply of strapping means 12 arranged close to the ground with strapping means 14 wound on a drum 13, in particular thermally weldable plastic strap.

On posts 15, 15 ', a cross member 16 is arranged vertically movable in the direction of the double arrow 17. The cross member 16 forms a press plate for compressing the packaged goods 11 or is a component thereof and stores on its upper side only a roughly indicated, known strapping closure assembly 18, which is used to form a closure overlapping strapping ends of the later around the packaged goods 11 taut strapping is used. A strapping means storage 19 is assigned to the closure assembly 18 and, like the closure assembly 18, is driven and guided in a uniform movement and thus in synchronism with the press plate 16.

Both the posts 15, 15 'and the cross member 16 are assigned strapping guides 20 to 23 in the form of straight channels or channel sections of a known type. It is also known to form the portal-like strapping guide channel structure 20 to 23 into a self-contained strapping guide frame in that a lance or a bayonet 24 underneath the packaged goods 11 or the pallet on which it is stored, on the bottom contains a straight strapping guide channel.

So that the strapping means 14 can be guided around the packaged goods 11, it must first be fed to the closure assembly 18. For this purpose, a strapping device infeed device 25 is provided directly behind the strapping stock 13, which, by means of strapping conveyor rollers 26, at least one of which is mechanically driven and the other is positively coupled to the strapping device feed, denotes the strapping device 14 into a strapping guide 28 Advance, which is arranged next to the post-like strapping guide 21 and parallel to it (behind it in the drawing). On this strapping guide 28, a strapping device 29 is arranged to be vertically movable, which has the task of transferring the strapping device 14 at the point at which the strapping device deflection 29 is located to a horizontally arranged strapping device transfer line 30, which it is used for Closure unit 18 continues. In the exemplary embodiment, this happens through the strapping material store 19. As soon as the leading free strapping end has reached a desired position in the closure assembly 18, the starting position for a first strapping of a packaged product 11 is reached.

The packaged goods 11 to be strapped have been conveyed into the strapping zone perpendicular to the drawing plane. The strapping means 14 is again by means of a two conveyor rollers and the closure unit 18 assigned conveyor 32, namely counterclockwise with respect to FIG. 1 through the strapping guides 20, 21, 24, 22, and 23 and through the strapping means 33 to 36 located between them in the strapping path until the front end of the strapping means 14 again in the closure unit 18.

Already during this guiding of the strapping means or immediately thereafter, the pressing plate 16, the closure assembly 18 and the belt store 19 lower down onto the top of the packaged goods 11, which is now compressed to a large extent depending on the nature and requirements. In order to then tighten the strapping 14 around the compressed packaged goods 11, the drive of the strapping conveyor rollers 32 is reversed so that they pull back the strapping means 14 brought in by the strapping stock 12, while the other end of the strapping means is held on the closure assembly 18 by means of a clamp. Due to the strapping means retraction, the strapping means 14 is pulled out from the inside of all the strapping means guides which are designed for this purpose in a known manner, for example thus have flexible lips or flaps which open against spring action.

From the above description it can be seen that the strapping guide frame 31 formed from the strapping guides 20-23 and the strapping deflections 33-36 represents a very long orbit for the strapping.

It is therefore understandable that difficulties in the strapping supply can occur if it is left solely to the conveyor 32 to shoot the strapping through the strapping guide frame 31 in a manner encircling the packaged goods 11. For this reason, it is already known to assign an additional conveyor, designated 37, to the strapping guide frame 31 or to integrate it into the orbit of the strapping 14 in addition to the conveyor device 33. It has proven to be advantageous to arrange the additional conveyor 37 at a location on the strapping guide frame 31 at which the strapping device 14 transported by the conveyor 32 has covered approximately 2/3 of its distance for a complete strapping guide frame filling. Consequently, in the exemplary embodiment shown in FIG. 1, the additional conveyor 37 is provided behind the third strapping means deflection 35 in the region of the second vertical frame section 22.

Before the essential components and properties of the additional conveyor 37 are described and illustrated in more detail on the basis of FIGS. 2 to 5 on the one hand and FIGS. 6 to 9 on the other hand, a look at the prior art should first be taken as it is shown in FIG. 10 and Fig. 11 is shown schematically. As the essential components, the known additional conveyor 37 'has two rollers 38' and 39 'designed as rollers. The rotatable roller 38 ', which is held in a fixed position, is assigned to the outside of the strapping guide frame 31 and by means of its not shown Motors can be driven in rotation. The second roller 39 ′ engages on the opposite side of the strapping means 14 and is consequently assigned to the inside of the strapping means guide frame 31. In the conveying position, the axes 40 'and 41' of the two rollers 38 'and 39' are parallel to one another and parallel to the orbit defined by the longitudinal advance of the strapping means 14, namely on the one hand in front of and on the other hand behind the orbit. So that the strapping means 14 can be drawn in from its loading position within the strapping means guide frame 31 onto the circumference of the package, it is necessary to ventilate the roller 39 ′ which is arranged towards the inside of the guide frame. This ventable roller 39 'is therefore mounted on a swivel arm 42 which can be swiveled out of the position according to FIG. 10 into the position according to FIG. 11 by means of a lifting magnet 43, which is indicated by the arrow denoted by 44. As can be seen, the roller 39 'must be pivoted out so far that it is practically no longer in overlap with the roller 38' so that the strapping means 14 can snap towards the packaged goods 11 unhindered. The control of the solenoid 43 'must be clocked depending on the machine cycle. Since, on the other hand, in the position shown in FIG. 10, the pair of rollers 38 '/ 39' must also be able to grasp the incoming end of the strapping means 24 in the nip, the particularly complex measures explained above on the roller 38 'were necessary.

2, on the basis of which a first exemplary embodiment of the invention is explained, the Additional conveyor 37 - initially in accordance with the prior art - again two rollers 38 and 39 for conveying the strapping means 14, but their axes are not arranged in front of and behind the orbit defined by the movement of the strapping means 14, but on the two sides of the Orbit, and the axes 40 and 41 are not oriented parallel to the orbit, but enforce this essentially perpendicular. The consequence of this is that the strip shown, which is flat in cross section, is contacted as strapping means 14 not by its broad sides, but rather by the narrow longitudinal edges 14 'of the rollers 38 and 39, which here are not designed as wide rollers but as flat, disc-shaped wheels are.

In detail, the arrangement is such that the roller 38 is rotatably driven by a motor 45 and that on the end of the axle 40 remote from the roller 38, a pinion 46 is rotatably mounted, which meshes with a pinion 47, which at the associated end of the axis 41 sits, the other end of which carries the second roller 39.

To hold the parts described, two receptacles 48 and 49 are used, each around an axis 50 and 51 parallel to the plane of the drawing and thus parallel to the longitudinal direction of the strapping means 14 or to the orbit of the strapping means 14 in the direction of the arrows 52 in FIG. 4 and 53 are pivotable. The arrangement of the pivot axes 50 and 51 is deliberately made close to the gears 46 and 47 so that they are always, ie also in the case of the pivoted apart Position according to Fig. 4 do not lose their meshing engagement.

The two rollers 38 and 39 are tensioned against one another by means of a spring 54. The spring 54 is designed as a tension spring and its spring force can be adjusted via adjusting spindles 55 that can be reached from opposite sides.

The roller gap is limited by stops 56 which can be set independently of one another and which are likewise designed as screw spindles and are supported on a central receptacle 57 which is connected to a machine-fixed console which is not shown in FIGS. 2 and 4 but is indicated in FIG. 1 by 58 . The free ends of the adjustable stop spindles 56 serve as stops for the central webs of the holders 48 and 49, as can be seen from FIG. 2 and also from FIG. 4. Since each receptacle 48 and 49 is assigned its own adjusting spindle 56, a lateral adjustment of the roller gap can be carried out, i.e. the rollers 38 and 39 can be aligned in their exact transverse position to the strapping means 14.

In addition, the construction is additionally carried out so that by means of a lever mechanism 59, not shown in detail, the pivoting out, for example, of the roller 38 in the direction of arrow 52 inevitably leads to the second roller 39 being pivoted out accordingly in the direction of arrow 53, even if no force directly affects them themselves.

The circumferential surfaces of the rollers 38 and 39 which frictionally drive the strapping means 14 on its longitudinal edges are, as clearly illustrated in FIGS. 2 and 4, concave, in particular V-shaped arrows. This ensures an exact centering of the strapping means 14 in the roller gap and on the other hand also favors the outward movement of the rollers 38 and 39 (arrows 52 and 53) when the strapping means 14 is pulled off in the direction of the arrow 60. This situation is shown schematically in FIG. 4, and FIG. 5 shows the associated view.

While in the embodiment according to FIGS. 2 and 5, the release of the rollers 38 and 39 takes place directly by pulling the strapping means 14 in the direction of the arrow 16, a further embodiment is shown in FIGS. 6 to 9, which differs from the first described distinguishes that additionally folding strapping retaining plates 61 and 62 are provided, which also cover the strapping guide channel 31 in the area of the additional conveyor 37 to the inside of the frame 31. The essential difference from the first embodiment is that when the strapping means 14 is pulled off in the direction of the arrow 60, the strapping means 14 peels out of the flaps, opening the flaps. Since the flaps 61 and 62 are connected to the rollers 38 and 39 in a uniform movement, by also being attached to the holders 48 and 49 in the exemplary embodiment, this means that the rollers 38 and 39 are already released when this comes out of the flaps 61 peeling strapping 14 the position of the Rolls 38 and 39 reached. Only when the strapping means 14 is also pulled out of the area of the flaps 62, the rollers 38 and 39 return from their release position (FIGS. 8 and 9) to the position corresponding to FIGS. 6 and 7 in which they come in can grasp and promote newly arriving strapping 14.

Both embodiments described have the same mode of operation in common. The lifting of at least one roller 38 or 39, in the exemplary embodiment the synchronous ventilation of both rollers 38 and 39 at the same time, is done either directly by accessing the strapping means 14 on the peripheral surfaces of the rollers 38 and 39 (FIGS. 2 to 5) or indirectly by the fact that Strapping means 14 directly engages the flaps 61, which in turn move the rollers 38 and 39 to the release position.

As can be seen in particular from a comparison of FIG. 3 with FIG. 5 (or FIG. 7 with FIG. 9), only very small pivoting paths are required to release the strapping means 14. The force exerted by the belt 14, which is necessary in order to be released from the drive of the additional conveyor 37, is essentially determined by the adjustable force of the spring 54. In any case, this force is so great that a reliable, frictional conveying of the strapping means 14 by the rollers 38 and 39 is possible, on the other hand so low that the pressure 38 and 39 on the narrow longitudinal edges 14 'of the strapping means 14 is not sufficient to disadvantageous longitudinal kinks or - cause corrugations of the strap-like strapping in particular.

Insofar as the description of the invention has been described with reference to a band which is preferably rectangular in cross section, it now goes without saying, after extensive knowledge of the invention and its properties, that cord-shaped strapping means could also be easily used with the aid of the additional conveyor 37. Even then, the invention differs in the described advantageous manner from the prior art corresponding to FIGS. 10 and 11.

Claims (9)

Device for strapping packaged goods by means of a cord-like or strap-like strapping means, in particular a thermoplastic plastic strap, with a strapping means guide frame, through which the strapping means is conveyed by means of a strapping means conveying device in order to circumnavigate the packaged goods along an orbit, and with a sealing unit for the ends of the freed from the strapping guide frame around the package tightened strapping means, with the strapping guide frame being assigned a strapping means additional conveyor downstream of the strapping means conveying device, which pushes the leading band area supportively through the strapping means guide frame and a pair of rollers which primarily engage the strapping means with frictional engagement comprises transversely to the orbit aligned axes of rotation, wherein at least one roller is arranged ventable to release the strap, characterized in that the axes (40, 41) of the rollers (38, 39) laterally next to the orbit penetrate the plane defined by it and the at least one ventable roller (38) against the action of one against the strapping means (14) and thus against the second roller (39) loading spring (57) from the strapping movement path to the side. Device for strapping packaged goods according to claim 1 by means of a band with a flat cross-section as a strapping means, characterized in that the rollers (38, 39) of the additional conveyor (37) on the Attack the narrow sides or longitudinal edges (14 ') of the strapping means (14). Device according to claim 1 or 2, characterized in that the essentially disk-shaped rollers (38, 39) have a fillet-like to concave-swept circumferential profile. Device according to one of claims 1 to 3, characterized by automatic lateral swiveling out of the at least one ventable roller (38) only as a result of the transverse pull (arrow 60) of the strapping means (14) released from the strapping guide frame (31). Device according to one of the preceding claims, characterized in that at least one swing-out flap (61, 62) covering the strapping guide frame (31) inwards is assigned to the additional conveyor (37), the ventable roller (38) is uniform in motion with the flap ( 61, 62) is connected and the roller (38) is released as a result of the transverse pull (arrow 60) of the strapping means (14) on the flap (61). Device according to one of the preceding claims, characterized in that in each case both rollers (38, 39) or both flaps (61) are cushioned against one another and in a symmetrical arrangement with respect to the longitudinal center of the guideway or the strapping means (14) can be pivoted towards or away from one another (Arrows 52, 53) are stored. Device according to one of the preceding claims, characterized in that the rollers (38, 39) are tensioned against one another by means of a force-adjustable tension spring arrangement (54, 55). Device according to one of the preceding claims, characterized in that the rollers (38, 39) are assigned adjustable stop means (56, 57) for adjusting the roller gap width and, if necessary, for lateral adjustment of the roller gap. Device according to one of the preceding claims, characterized in that each roller (38, 39) is arranged at one end of a roller axis (40, 41) which is held by a receptacle (48, 49) which is pivotally mounted away from the roller (38, 39) ) is held, and the rollers (38, 39) are positively coupled by means of friction or gear wheels (46, 47) attached to the other end of the roller axis (40, 41).

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