EP3453529B1 - Box baler with sliding door and method for operating such a box baler - Google Patents

Description

I. Area of application

The invention relates to a baling press, as is often used for compacting and pressing loose material, for example packaging films, cardboard boxes or plastic bottles intended for recycling, for example in the logistics sector and often also by supermarkets for their packaging materials.

II. Technical background

• Bei Kanal-Ballenpressen wird das Material in einen Presskanal hineingepresst, und durch einen dort vorliegenden Widerstand als Gegenkraft komprimiert, wobei der Widerstand durch die Reibung des bereits erzeugten, komprimierten Materials beim Weiterschieben in dem Presskanal entsteht, der an seinem freien Ende nicht verschlossen ist. Die Pressrichtung der Pressplatte ist also in Richtung der Öffnung des Presskanals gerichtet.
• Bei Kasten-Ballenpressen wird das Material von einem Pressstempel in einem allseits geschlossenen Presskasten zusammengepresst, wobei der Pressstempel die eine Wand des Pressraums, also des Presskastens, darstellt.

Eine Seite des Presskastens ist dabei durch eine Entnahme-Tür im Pressbetrieb verschlossen und kann für die Entnahme des fertigen Pressballens geöffnet werden. Die Pressrichtung, in der sich der Pressstempel bewegt, kann in Richtung dieser Entnahmeöffnung gerichtet sein, oder auch quer hierzu. In der Praxis ist bei einer Kastenpresse, bei der die Pressrichtung in Richtung Entnahmeöffnung, also Entnahme-Tür, gerichtet ist, die Pressrichtung häufig horizontal vorgesehen.There are two types of baling presses:

• In channel baling presses, the material is pressed into a press channel and compressed as a counterforce by the resistance present there, whereby the resistance arises from the friction of the already produced, compressed material as it is pushed further into the press channel, which is not closed at its free end. The pressing direction of the press plate is therefore directed towards the opening of the press channel.
• In box balers, the material is pressed together by a press ram in a press box that is closed on all sides Press ram which represents a wall of the press room, i.e. the press box.

One side of the press box is closed by a removal door during pressing operation and can be opened to remove the finished pressed bale. The pressing direction in which the press ram moves can be directed in the direction of this removal opening, or also transversely to it. In practice, in a box press in which the pressing direction is directed towards the removal opening, i.e. the removal door, the pressing direction is often horizontal.

In the case of box balers, in which the pressing direction is approximately parallel to the plane of the removal opening, the pressing direction is often vertical from top to bottom.

In both cases, the removal door is usually arranged approximately vertically.

The present invention deals with box balers, in which there is a lockable removal door that must withstand the pressing pressure during pressing operation, and in particular their opening mechanism.

Basically, both sliding doors and swing doors are known.

Swing doors have the advantage that when open they do not require any additional height, i.e. beyond the press box, but in order to be able to withstand the pressing pressure, when closed they require a stable and complex locking device, which is usually released manually before the door is opened must.

A sliding door has the advantage that it does not necessarily require such an additional locking mechanism as long as the guides of the sliding door are solid.

The disadvantage of the sliding door is that when open it requires additional space either in the height or in the width of the press box, and the shifting of the entire door weight to open usually requires a working cylinder such as a hydraulic cylinder, and not opened by hand can be.

Another problem when opening is the force still exerted on the removal door across the door level:
Although the press plate is previously retracted slightly in order to no longer exert any pressing force on the bale formed, on the one hand the friction of the press bale produced on the surrounding walls, which essentially hold the press bale in position, and on the other hand the expansion that occurs after the press force has been eliminated of the bale ensures that there is still a considerable force on the removal door.

In the case of a swing door, this means that the locking device is still somewhat under tension and therefore considerable force must be applied to release this locking device.

In the case of a sliding door, this means that the movement of the sliding door could not simply be planned in the direction of the door level, but rather the sliding door was first intended to be lifted away from the opening level in order to eliminate the existing residual pressure on the removal door, and only then has the sliding door been moved across the press box to release the removal opening.

This lifting movement is also necessary so that the grooves machined into the contact surface of the sliding door and the strapping wires of the fully strapped bales located therein can come out of these grooves when the door is opened.

• betätigt wird, hat dies weitere Nachteile zur Folge:
  Zum einen kann die Schiebetür dabei nur mittels einzelner, entlang der in Bewegungsrichtung verlaufenden Seitenkanten der Schiebetür zueinander beabstandeter, Führungszapfen in einer kulissenartigen Führung am Pressengehäuse geführt werden, um zunächst die besagte Abhebebewegung und erst danach die eigentliche Öffnungsbewegung durchzuführen.

As mentioned, such a sliding door usually uses a working cylinder - usually two working cylinders arranged on opposite sides in order to avoid tilting when opening and closing

• is operated, this results in further disadvantages:
  On the one hand, the sliding door can only be guided in a slot-like guide on the press housing by means of individual guide pins spaced apart along the side edges of the sliding door running in the direction of movement in order to first carry out the said lifting movement and only then the actual opening movement.

However, this means that in the closed position either the entire load rests on these guide pins, or an additional locking device must be provided which supports the sliding door against the pressing forces exerted on it.

Another consequence is that the working cylinder(s) moving the sliding door must be pivotably attached both to the end on the sliding door side and to the end on the frame side.

From the EP 241231 A2 In this context, a box baler is known, which can be closed by a sliding door on the front side opposite the press ram.

This document also discloses a baler with the features of the preamble of claim 1.

There is no provision for strapping the bales formed by the baler.

From the US 6347931 B1 a baler is also known in which a sliding door closing the press channel has surface areas that are inclined to the contact surface according to Figures 8 and 9, but it is clearly stated in column 7, line 31 that the sliding door 70 always maintains the same longitudinal position when it closes (in the transverse direction).

III. Presentation of the invention a) Technical task

It is therefore the object according to the invention to avoid the disadvantages described above and yet to enable a simple and cost-effective construction in which the opening and closing of the sliding door can also be carried out very easily.

b) Solution to the task

This task is solved by the characterizing features of claims 1 and 13. Advantageous embodiments result from the subclaims.

With regard to the box baler , this task is solved in that the sliding door is moved between the open position and the closed position along door guides that run straight, at an acute angle to the opening plane of the removal opening, which is closed by the sliding door in the closed position .

As a rule, this opening plane runs perpendicular to the direction of the pressing box, which is also the pressing direction when the pressing direction is directed towards the removal opening.

If this angle is relatively small, i.e. less than 30°, better less than 20°, better less than 10° or even less than 5°, it is possible to design and arrange the cross-section of the threading grooves in the sliding door for the strapping element in such a way that that when the sliding door is opened, the in these Threading groove sections of the strapping element - a strapping band or strapping wire - can slide out of the opening of the cross section of the threading groove without the need for a first lifting movement of the sliding door essentially perpendicular to the plane of the removal opening.

In addition, the movement that the sliding door has to make when opening and closing is an exclusively straight movement, which greatly simplifies the construction:
On the one hand, the direction of action of the door drive - no matter what it is made of - can be arranged parallel to the guiding direction of the sliding door, i.e. its direction of movement when opening or closing.

In the case of a door drive, consisting of one or more working cylinders, usually hydraulic cylinders, such a hydraulic cylinder can be arranged on both sides of the press housing in a direction that corresponds to the guide direction in which the guides for the sliding door run, so that such a working cylinder can also be arranged Its two ends do not have to be attached in an articulated manner to the sliding door on the one hand and to the press housing on the other, but a rigid attachment is sufficient.

Above all, individual, small-area guide pins on the sliding door are not necessary in order to guide them in separate link guides and to realize the lifting movement, but rather the guide elements on the sliding door and/or the door guides can extend over a large part - at least 40%. better at least 60%, better at least 80%, better at least 90% - of the extension direction of the sliding door in the guide direction, for example forming a guide bar or a guide groove.

Particularly on the side facing away from the press box with respect to the guide elements, the door guides should be present over as large a proportion as possible of the extension of the sliding door in the guide direction and, in particular, be present continuously.

This guide element does not have to extend over the entire extent in the guide direction, but can consist of individual elements - although this is disadvantageous in terms of production technology - and could theoretically also consist of a large number of guide pins spaced slightly apart from one another, but the total area in which the guide elements are Sliding door rests against the door guides in the closed position, many times larger than when only two guide pins are installed on each side in a respective link guide.

In this way, the guide unit consisting of a guide element and door guide can itself absorb much higher loads across the door plane than just two relatively small guide pins, so that for reasons of stability alone, a sliding door designed in this way does not require an additional support device in the form of a locking device to absorb the pressing forces .

Securing the closed position can also be achieved in a simple manner by using the door drive, for example the hydraulic cylinder, to move the sliding door into the closed position, usually in the form of a stop in the door guides, and in this position the closing and/or or discharge line of the working cylinder is closed by a valve. The tightness of the working cylinder is sufficient to prevent the sliding door from opening unintentionally, caused by the pressing forces, due to the angle mentioned at the beginning being as small as possible between the direction of movement of the door and the opening level of the removal opening on the press housing.

Ideally, the guide unit formed from guide elements and door guides is designed to be self-locking, but at least designed in such a way that only a very small additional holding force, in particular of less than 50 N, in particular of less than 30 N, is required to hold the sliding door, especially at the maximum possible Keep the pressure of the press plate against the resulting bale in the closed position.

If, for safety reasons or due to existing regulations, a form-fitting safeguard against unintentional opening of the sliding door is still required, this can be designed in such a way that it only has to absorb small forces acting on the sliding door in the pressing direction and/or in such a way that it is connected to the door -Drive is operatively connected, and is opened together with the sliding door, in particular only slightly beforehand, by the same door drive.

Even if the locking mechanism is mechanically coupled to the door drive, the locking mechanism can be opened before the sliding door starts moving.

According to the invention, due to the oblique, but straight, movement of the sliding door, the pressure on the sliding door should of course soon decrease with increasing movement out of the closed position, which is why the angle between the direction of movement of the sliding door and the opening plane of the removal opening should be at least 1 °, better at least 2°, better at least 3°.

Since no pivoting attachment of a working cylinder serving as a door drive, such as a hydraulic cylinder, is necessary, this is especially fixed, i.e. immovable, in relation to the press housing and/or also on the sliding door.

In order to prevent tilting, a working cylinder is preferably arranged on both sides of the removal opening.

Especially for automatic operation, it makes sense that there is a position sensor that at least detects when the sliding door has reached the end position in the closed position, because only after this signal can the control - which controls at least all moving elements of this box baler - move the press plate in the pressing direction and start pressing operation.

Preferably, reaching the end position of the sliding door in the open position should also be detected, because only in response to this signal should the control cause the bale to be pushed out through the then open removal opening, which is usually done by the press plate itself or an ejector arranged in the press plate. Piston with a reduced end face takes place.

In order to always have a complete overview of the operating status of the sliding door, it makes sense for the position of the sliding door along its entire movement path to be detected using a position sensor, for example a cable pull sensor or a contactless sensor, such as a magnetostrictive sensor, which is also good can be arranged protected inside the hydraulic cylinder.

In order to strap the bale produced in the press box with strapping material before removal in such box balers, pieces of the strapping element, usually a strapping wire or a relatively stiff strapping band, are usually cut to length Outside of the press box, threading grooves formed through corresponding openings and in the inner surfaces of the press box and the press plate are pushed around the bale, preferably in a horizontal plane, until the front end protrudes again through this opening in the wall of the press box, so that the two ends are connected to each other can be connected.

There are also threading grooves in the contact surface of the sliding door in which a section of the strapping element should lie and through which the strapping element is previously pushed through with its free end in front.

The fundamental problem here is that the cross section of these threading grooves must be open towards the pressing space, so that when the material is pressed, some material can be pressed into the threading grooves, making the subsequent threading of the strapping element more difficult or, in extreme cases, completely impossible.

If these threading grooves in the sliding door are located transversely to the guide direction of the sliding door, in order to move out the section of the strapping element lying therein, either the opening of the cross section of the threading groove must be made very large or the sliding door must perform a lifting movement at the beginning of its opening movement is essentially perpendicular to the opening plane.

What at first glance appears to be a disadvantage of the direction of movement of the sliding door, which is only at an acute angle to the opening plane, namely the difficulty in moving the strapping element out of the threading groove of the sliding door, can actually be transformed into a significant advantage by taking appropriate measures:
This is achieved in that the upper edge of the groove pointing towards the groove opening of the groove cross section - pointing, for example, in the opening direction of the door - does not point primarily in the direction of the press box, but rather points primarily in the direction of movement of the sliding door, i.e. at an acute angle to the opening plane of the press box.

Above all, however, the upper groove flank can reach down at least to the free end of the lower groove flank, in particular partially or preferably completely covering it in the pressing direction.

This makes it very difficult for material to get into the threading groove in the sliding door during pressing because it is covered transversely to the door level and the material would have to find a labyrinth-like path into the groove cross section.

For this purpose, the acute angle at which the groove flank adjacent to the press box lies to the opening plane is preferably equal to or greater than the acute angle between the sliding door and the upper groove flank.

For this reason, the groove flank facing away from the press box also runs at an acute angle to the opening plane, which is preferably equal to or greater than the angle between the upper groove flank and the opening plane.

With regard to the method, a box baler - especially if it is designed as described above - can be operated to open the sliding door in such a way that this sliding door is moved in an overall straight and not curved guide direction between the open position and the closed position.

It may be that, especially at the beginning of the opening movement, a slightly greater release force has to be applied due to the still relatively high static friction between the bale and the sliding door than during a first lifting movement approximately perpendicular to the opening plane.

However, with one or two hydraulic cylinders as a door drive, this is also insignificant in terms of cost due to the appropriate dimensioning compared to the fact that the overall design becomes much simpler, easier to maintain and easier to use.

Preferably, the contact surface of the sliding door is always in a parallel position to the opening plane when opening or closing.

Even if a locking device is present, it can be designed in such a way that it does not have to be unlocked beforehand and in particular not manually before the opening movement of the sliding door is effected by means of the door drive, but rather by coupling the door drive with the locking device, in particular its unlocking element , this can be done automatically by the door drive together with the door opening.

c) Embodiments

Figur 1a:

Eine horizontal arbeitende Ballenpresse nach dem Stand der Technik in einer teilgeschnittenen Seitenansicht entlang Linie A - A der Figur 1b, vor Beginn des Pressbetriebes und bei geschlossener Schiebetür,

Figur 1b:

Eine Aufsicht auf die Kasten-Ballenpresse der Figur 1a im dort dargestellten Betriebszustand,

Figur 2:

Eine teilgeschnittenen Seitenansicht der Kasten-Ballenpresse gemäß Figur 1a mit einem bereits teilweise im Presskasten aufgebauten Ballen, aber bei noch geschlossener Schiebetür,

Figur 3:

In der gleichen Seitenansicht wie Figur 1a und 2 die Ballenpresse gemäß Figur 1a mit geöffneter Schiebetür und bereits teilweise aus dem Presskasten 50 ausgestoßenem Ballen,

Figur 4a:

Eine erfindungsgemäße Kasten-Ballenpresse in einer Darstellung gemäß Figur 1a,

Figur 4b:

Die Kasten-Ballenpresse gemäß Figur 4a in einer Ansicht gemäß Figur 1b,

Figur 5:

Die Kasten-Ballenpresse in einer Ansicht gemäß Figur 4a bei geschlossener Schiebetür und bereits teilweise aufgebautem Ballen,

Figur 6a:

Die Ballenpresse in einer Ansicht gemäß Figur 4a, mit geöffneter Schiebetür und bereits teilweise ausgestoßenem Ballen,

Figur 6b:

Eine Aufsicht auf die Schiebetür betrachtet in Pressrichtung,

Figur 7a:

Eine Vergrößerung des Bereiches der Schiebetür aus Figur 4a bei geschlossener Schiebetür,

Figur 7b:

Eine Darstellung analog zu Figur 7a mit bereits leicht nach oben verfahrener Schiebetür 5.

Embodiments according to the invention are described in more detail below by way of example. Show it:

Figure 1a:

A horizontally operating baler according to the prior art in a partially sectioned side view along line A - A of the Figure 1b , before the start of pressing operation and with the sliding door closed,

Figure 1b:

A top view of the box baler Figure 1a in the operating state shown there,

Figure 2:

A partially sectioned side view of the box baler according to Figure 1a with a bale already partially built up in the press box, but with the sliding door still closed,

Figure 3:

In the same side view as Figure 1a and 2 the baler according to Figure 1a with the sliding door open and the bale already partially ejected from the press box 50,

Figure 4a:

A box baler according to the invention in a representation according to Figure 1a ,

Figure 4b:

The box baler according to Figure 4a in a view according to Figure 1b ,

Figure 5:

The box baler in a view according to Figure 4a with the sliding door closed and the bale already partially built up,

Figure 6a:

The baler in one view according to Figure 4a , with the sliding door open and the bale already partially ejected,

Figure 6b:

A top view of the sliding door viewed in the pressing direction,

Figure 7a:

An increase in the area of the sliding door Figure 4a with the sliding door closed,

Figure 7b:

A representation analogous to Figure 7a with the sliding door already moved slightly upwards 5.

The Figures 1a - 3 show a box baler 1, as is known from the prior art.

Such a box baler 1 comprises a press box 50 running in the longitudinal direction 10, usually the horizontal direction, which is delimited by the left and right side walls 2a, 2b of the press housing 2 as well as the upper wall 2c and the lower wall 2d.

In the figures, the pressing direction 10 'is directed from right to left along the longitudinal direction 10, so that the left end of the press box 50 is open and can be closed by a sliding door 5 in this case, while the right end of the press box 50 is movable in the longitudinal direction 10 Press plate 3 is limited. The rear, here right, end of the press housing 2 is closed by a permanently mounted rear wall between the side walls 2a, 2b and the upper wall 2c and lower wall 2d, on which the press cylinder 16 attached to the back of the press plate 3 is supported.

The loose material 99, such as cardboard, enters the press box 50 through a transition opening 51 ', which is present approximately in the longitudinal direction 10 in the central region of the upper wall 2c, with a filling funnel 25 being placed on the transition opening 51 ', in the upper filling opening 51 of which the material 99 is placed is thrown in. Accordingly, the filling opening 51 of the filling funnel 25 is usually larger than the transition opening 51 'from the filling funnel 25 through the top wall 2c into the press box 50, with the filling funnel 25 also serving as a storage space for materials 99 to be pressed.

• einer Ausgangsstellung gemäß Figur 1a , in der sich die Frontfläche der Pressplatte 3 in Pressrichtung 10' hinter der Übergangsöffnung 51' in der Oberwand 2c befindet und
• einer Pressstellung, in der die Pressplatte 3 über diese Übergabeöffnung 51' in der Oberwand 2c in Pressrichtung 10' hinwegverfahren ist und die vorher im Presskasten 50 befindlichen losen Materialien 99 beginnt, zu einem Ballen 100 gegen die geschlossene Schiebetür 5 zu verpressen, dessen Dicke in Längsrichtung 10 mit jedem Presshub der Pressplatte 3 größer wird.

Densely pressed bales 100 are to be produced from the loose material 99, as in the Figures 2 and 3 It can be seen why, during pressing operation, the front removal opening 52 of the press box 50 at the left end is closed by a door, in this case a sliding door 5, against which a press plate 3 filling the cross section of the press box 50 is placed several times in succession

• according to a starting position Figure 1a , in which the front surface of the press plate 3 is located in the pressing direction 10 'behind the transition opening 51' in the top wall 2c and
• a pressing position in which the press plate 3 has moved over this transfer opening 51 'in the top wall 2c in the pressing direction 10' and the loose materials 99 previously located in the press box 50 begin to be pressed into a bale 100 against the closed sliding door 5, the thickness of which is in Longitudinal direction 10 becomes larger with each press stroke of the press plate 3.

The press plate 3 is moved back and forth and in particular moved forward in the pressing direction 10 'by means of a press cylinder 16 arranged behind the press plate 3 in the pressing direction 10', or several press cylinders 16 as in Figure 1b indicated, which are supported on the rear wall of the press housing 2.

It is known that the press plate 3 is guided in the press box 50 by being attached to the front of a press carriage 15 in the pressing direction 10 ', which moves, for example, by means of rollers 17 on the lower wall 2d of the press housing 2.

From the upper end of the press plate 3, a cover plate 15a extends backwards against the pressing direction 10 ', which, when viewed from above, extends from the filling funnel 25 into the press box 50 at least over the width of the transfer opening 51' - the length of which is dimensioned such that In the pressing position that is at the forefront in the pressing direction 10' and can be reached through the press plate 3, the underside of the transfer opening 51' is still closed by the filling funnel 25 in the press box 50 in order to prevent loose material 99 located in the filling funnel 25 from slipping into the area behind the pressing plate 3 impede.

Such sliding into the press box 50 should only occur after the press plate 3 has moved back behind the transfer opening 51 'into the then existing free space between the already partially built bale 100 and the press plate 3.

In order to prevent loose material 99 from jamming when the press plate 3 moves forward across the transfer opening 51 ', the upper transverse edge of the press plate 3 is designed on its front surface as a knife edge 3a, which shears off material 99 located in the area of the transfer opening 51' compared to the one in Pressing direction 10 'front edge of the transfer opening 51', which can also be designed as a counter knife on its lower edge.

• in aller Regel zuerst die Pressplatte 3 etwas zurückgefahren, um den Pressdruck vom umschnürten Ballen 100 zu nehmen,
• die Schiebetür 5 geöffnet und
• wie in Figur 3 dargestellt der Ballen 100 aus der Entnahmeöffnung 52 des Presskastens 50 ausgeschoben auf einen Transportträger wie etwa eine Palette 18, wobei das Ausschieben entweder mittels der Pressplatte 3 oder eines separaten Ausstoßers erfolgen kann.

As soon as, for example, after a preset number of pressing strokes or depending on the achievement of a minimum length of the bale 100 during the pressing strokes, the bale 100 is completed, the back of which is then still in the pressing direction 10 'in front of the transfer opening 51', the bale 100 is still closed with the sliding door 5 strapped in several horizontal levels one above the other with a strapping material such as a strapping wire 20, and only then

• As a rule, first the press plate 3 is moved back slightly in order to take the pressing pressure off the tied bale 100,
• the sliding door 5 opened and
• as in Figure 3 shown, the bale 100 is pushed out of the removal opening 52 of the press box 50 onto a transport carrier such as a pallet 18, whereby the pushing out can take place either by means of the press plate 3 or a separate ejector.

When strapping the finished bale 100 in the closed press box 50, strapping wires cut to length are guided around the bale 100 in a horizontal plane in several, here four, levels one above the other, and their ends on both sides are connected to one another, so that a closed, relatively tight A strapping ring attached to the bale 100 is created.

After the pressing pressure is removed by the press plate 3 in the direction of the closed sliding door 5, the bale 100 expands slightly, which is initially only possible in the longitudinal direction 10 in the press box 50, whereby the closed strapping rings made of strapping material are tensioned.

The respective strapping wire 20 is guided around by the fact that several longitudinal grooves 21 which run at a distance from one another in the longitudinal direction 10 are incorporated into the inner surfaces of the side walls 2a, 2b of the press housing 2, and also at the same height - with the sliding door 5 in its closed state - threading grooves 12 horizontal, but running transversely to the longitudinal direction 10.

Analog threading grooves 12 are incorporated into the front surface 3a of the press plate 3 at the same height, i.e. also aligned with the ends of the longitudinal grooves 21.

Through one or two corresponding small through openings in one of the side walls, e.g. 2b, of the press housing 2 at the level of each threading groove 12, such a strapping wire 20 is pushed with the free end first along one of the threading grooves 12 in the front surface 3a of the press plate 3, on which opposite end is automatically deflected by appropriate shaping into the longitudinal groove 21 of the opposite side wall 2a running in the longitudinal direction 10, from there further into the threading groove 12 in the contact surface 5a of the sliding door 5 and via the longitudinal groove 21 in the side wall 2a back to the threading opening in this side wall 2a, where the two free ends of the strapping wire 20 are connected to one another, for example by a so-called quicklink closure.

Since all of these grooves 12, 21 are open to the pressing chamber 50, after opening the sliding door 5, the strapped bale 100 can be pushed out of the pressing box 50 through its removal opening 52, for example onto a pallet 18, and transported away with a forklift. since the strapping rings 20 placed around the bale 100 can move out of the grooves 12, 21.

It should be clear that this threading of a strapping wire 20 through the grooves 12, 21 described does not work if the grooves are partially filled with material to be pressed, which is why the groove openings of the groove cross sections are kept as small as possible, i.e. are hardly larger than the thickness of the strapping wire used 20. According to the invention, it is about the design and movement of the sliding door 5, especially in interaction with the strapping of the bales 100:
With the state of the art according to Figures 1a - 3 When opening, the sliding door 5 performs a movement in the direction of movement 4 ', namely initially a lifting movement, in which the sliding door 5 is moved away from the removal opening 52 at a relatively large angle to the opening plane 52 ", but only over a relatively short distance Distance, and then moved up parallel to the opening plane 52" to release the removal opening 52.

The lifting movement serves to remove the remaining pressure still on the sliding door 5 from the sliding door 5 and, above all, to allow the strapping wires 20 lying in the threading grooves 12 of the sliding door 5 to slide out of them without any problems, so that the opening of the Groove cross section 13 of these threading grooves 12 can remain small. The cross-sectional shape 13 of the threading grooves 12 is generally still rectangular with two horizontally extending, mutually parallel flanks.

As the Figures 1a and especially Figure 1b show, such a direction of movement 4 'can only be achieved by two guide pins 23 protruding to the side from the side edges of the sliding door 5, the upper and lower guide pins 23 arranged on the same side usually being at different axial positions, so that each of They can be guided in a separate guide groove 24 in the manner of a backdrop.

However, this means that in the closed position the entire pressure load on the sliding door 5 would have to be borne by these relatively small guide pins 23, which is hardly possible in practice, which is why such a construction also requires a locking device such as approximately attachable pivot levers 14, as exemplified in the Figure 1a shown, and of which there are several distributed over the height and absorb the pressure load.

The locking device must be unlocked manually before the sliding door 5 is raised, which may require a lot of effort given the pressing force on the sliding door 5.

Like especially those Figure 1b shows, the sliding door 5 is moved in height by means of a hydraulic cylinder 7 as a door drive 6 on each side of the sliding door 5, the lower end of which is connected to the press housing 2 and the upper end of which is connected to the upper end of the narrow outside of the sliding door 5 .

As is already clear from the lateral offset of the direction of movement 4 'and in Figure 3 can be seen, the hydraulic cylinder 7 is at a different angle to the pressing direction 10 ' viewed in the side view when the sliding door 5 is raised and open than in the closed position. Therefore, the hydraulic cylinder 7 must also be attached to the press housing 2 at its lower end so that it can pivot about an axis running in the horizontal transverse direction.

The Figures 4a - 6b show the solution according to the invention, in which the direction of movement 4 'of the sliding door 5 when opening and closing is a consistently straight direction, with a relatively small, in any case acute, angle α between the direction of movement 4' and the opening plane 52 ", viewed in the Side view in the longitudinal direction 10 as in Figure 4a .

As a result, guide elements can be used that extend over a significantly larger guide area than the guide pins 23 in the prior art:
So on both sides of the sliding door 5 - as best in Figure 4b to recognize - a guide bar 9 protrudes outwards, which, when viewed from the side, has two mutually parallel flanks, both of which extend in the direction of movement 4 'and are therefore straight.

The guide bar 9 can extend over the entire height of the sliding door 5 and, when the sliding door 5 is closed, even upwards beyond the upper end of the removal opening 52.

Furthermore, it is possible for a strip-shaped door guide 4a to be arranged on the press housing 2 - viewed from the side outside the press box 50 when viewed from above - especially in the pressing direction 10 'behind the guide bar 9, which is also located outside the press box 50 when viewed from above and extends over the entire height of the press box 50 and even beyond.

This means that when the sliding door 5 is closed - when the contact surface 5a facing the press box 50 is parallel to the opening plane 52" of the press housing 2 and therefore generally vertical - the guide bar 9 is on its side due to the pressing force caused by the press plate 3, on the side facing away from this door guide 9, is supported over a large area.

Of course, for guiding the guide bar 9, there is also a door guide 4b, preferably also strip-shaped, on the side facing the pressing force, but this can only be present in the upper area, possibly only above the height of the press box 50 can or over the entire height if this door guide 4b is also located laterally outside of the press box 50 when viewed from above.

The further advantage is that - here too, the sliding door 5 is actuated by hydraulic cylinders 7 that are essentially upright on the side outside of it - the upper fastening end of the hydraulic cylinder 7 also moves in the direction of movement 4 'and therefore only in a straight line and therefore no Pivoting of the hydraulic cylinder 7 about its lower end relative to the press housing 2 is required.

Otherwise, the bale 100 is created, the sliding door 5 is opened and the bale 100 is ejected analogously to a known box baler, as shown in Figures 5 and 6 presented and previously based on the Figures 1a - 3 described.

So that in this rectilinear direction of movement 4', despite the relatively small angle α to the opening plane 52", the strapping wires 20 can come out of the threading grooves 12 running in the transverse direction in the front surface 5a of the sliding door 5 and preferably no material from the press box 50 into these threading grooves 12 beforehand can penetrate, according to the invention the following design of the cross section 13 of the threading grooves 12 in the sliding door 5 is selected, as based on Figures 7a , 7b shown:
The cross section 13 of the threading groove 12 has the necessary groove opening 13a towards the pressing chamber 50 so that the strapping wire 20 lying in the cross section 13 can come out of the threading groove 12. Accordingly, the narrowest point 22 of the cross section 13 is larger than the largest possible width of the cross section of the strapping material used, in particular a strapping wire 20, and in particular the opening 13a is the narrowest point 22 of the cross section 13.

The cross section 13 is laterally delimited by an upper groove flank 13b and a lower groove flank 13c, which run towards the groove opening 13a and are supported against one another in their rear area facing away from the groove opening 13a, preferably by a cross-sectional base, in particular are connected to one another.

Both the upper and lower groove flanks 13b, c as well as the cross-sectional base can be formed by metal strips, with the upper metal strip in particular preferably protruding over the contact surface 5a of the sliding door 5 facing the press box 50.

The upper groove flank 13b of the cross section 13 runs straight towards the groove opening 13a in its lower region and is steeper than the lower groove flank 13c. The upper groove flank 13b extends so far downward that its free lower end is preferably lower than the narrowest point 22 of the cross section 13, i.e. the smallest distance between the upper and lower flanks 13b, c, which is preferably the groove opening 13a .

As a result, viewed in the pressing direction 10 ', the narrowest point 22, preferably the groove opening 13 a, is covered by the upper groove flank 13 b, so that material 99 is pressed in from the pressing chamber 50 through the narrowest point 22 into the widened area of the cross section behind it 13 is very unlikely.

The upper groove flank 13b is inclined at an angle β2 relative to the door level 5" and is therefore more inclined than the direction of movement 4 'to the door level 5". The door level 5" usually runs parallel to the opening level 52".

The lower groove flank 13c preferably runs straight from its front to the rear end at an angle β1 to the opening plane 52", and flatter than the upper groove flank 13b in the area adjoining the groove opening 13a. The rear region of the upper groove flank 13b, which is further away from the groove opening 13a, is angled towards the front region of the upper groove flank 13b and preferably runs parallel to the lower groove flank 13c

Preferably, the upper groove flank 13b ends relative to the longitudinal grooves 21 for the strapping wire 20, which run in the side walls 2a, b and are located at approximately the same height, below the longitudinal groove 21, at least below the upper flank of the longitudinal groove 21, so that the groove opening 13a is at the level of the Longitudinal groove 21 is located when the sliding door 5 has already left its closed position.

How Figure 7b As can be seen, this design allows the strapping wire 20 to pass through the narrowest point 22, in particular the groove opening 13a, out of the threading groove 12 without any problems when the sliding door 5 begins to rise,

Preferably, the width of the narrowest point 22 should be at least a factor of 1.2; better by at least a factor of 1.5; better at least by a factor of 2, better at least by a factor of 2.5 larger than the largest cross section of the binding wire 20, and / or not larger than 5 times, better not larger than 4 times, better not larger than that 3 times the largest cross section of the binding wire 20.

Furthermore, in the Figures 7a , 7b a non-contact sensor 8 is shown on the top of the press box at its rear end, with which the closed position of the sliding door 5 can be detected:
In this case, the sensor 8 is arranged looking in the pressing direction 10 'in such a way that the upper end of the sliding door 5 is in front of it when it is in the fully lowered, closed position is not opposite and the sensor 8 then does not emit a signal.

As soon as the sliding door 5 has moved up even slightly from this completely closed position, it is opposite the sensor 8 and this emits a warning signal.

Of course, other types of sensors and/or other mounting positions of such a sensor are also possible, for example such that the sensor only emits a signal when the sliding door 5 is completely closed, and otherwise does not emit a signal.

REFERENCE SYMBOL LIST

1

Baler

2

Press housing

2a - d

Side wall

3

Press plate

3a

Knife edge

4, 4a, 4b

Door guide

4'

Leadership direction

4'a

Opening direction

4'b

Closing direction

5

sliding door

5a

Contact surface

5"

Door level

6

Door drive

7

Work cylinder, hydraulic cylinder

8th

Position sensor

9

Guide element, guide bar

10

Longitudinal direction

10'

Pressing direction

10"

Transverse plane

11

Transverse direction

12

threading groove

13

Groove cross section

13a

Groove opening

13b, c

Groove flank

13c1

Flank part

13c2

Flank part

14

Locking device

15

Press truck

15a

Cover plate

16

Press cylinder

17

role

18

palette

19

Foot

20

strapping wire

21

Longitudinal groove

22

narrowest place

23

Guide pin

24

Guide groove

25

Filling funnel

50

Press box

51

Filling opening

51'

Transition opening

52

removal opening

52"

Opening level

99

Cardboard, loose material

100

bale

Claims (15)

1. Box baler (1) for pressing loose material, preferably cardboard packaging (99), into bales (100), comprising

   - a pressing box (50) extending in the longitudinal direction (10), which is delimited by walls (2a to 2d) of a press housing (2) which extend in the longitudinal direction (10),

   - a pressing plate (3) which delimits the pressing box (50) at the rear and is movable between the walls (2a to 2d) in the pressing direction (10'),

   - a pressing plate drive, in particular a hydraulic cylinder (16),

   - a filling opening (51) for the loose material and a front-side removal opening (52) for the bale (100) being formed on the press housing (2), the removal opening (52) being in an opening plane (52"),

   - a sliding door (5) which can be moved back and forth relative to the press housing (2) between

   - a closed position closing the removal opening (52) and

   - an open position releasing the removal opening (52),

   - for which purpose the sliding door (5) has guide elements (9) which are guided along door guides (4) in a form-fitting manner,

   - a door drive (6) for moving the sliding door (5),
   characterized in that

   - the door guides (4) extend straight at an acute angle (α) of their guide direction (4") to the opening plane (52") of the removal opening (52), which is in particular the transverse plane (10") to the longitudinal direction (10), so that with increasing movement of the sliding door (5) out of the closed position, a pressure of the bale (100) acting thereon soon decreases, and in that the angle (α) between the movement direction of the sliding door (5) and the opening plane (52") of the removal opening (52) is at least 1°.
2. Box baler according to claim 1,
   characterized in that
   the angle (α)

   - is at most 30°, more preferably at most 20°, more preferably at most 10°, more preferably at most 5°,
   and/or

   - at least 2°, more preferably at least 3°.
3. Box baler according to either of the preceding claims,
   characterized in that,

   - in the closed position, the guide elements (9) and/or the door guides (4) lie opposite each other (4'), in particular rest against one another, over at least 50%, more preferably at least 80%, more preferably at least 90%, more preferably at least 95% of the length of the sliding door (5) in the guide direction,

   - in particular the guide elements (9)

   and/or the door guides (4) are designed to extend in the guide direction (4') in the shape of either a strip or a groove, and extend over at least 50%, more preferably at least 80%, more preferably at least 90%, more preferably at least 95% of the length of the sliding door (5).
4. Box baler according to any of the preceding claims,
   characterized in that
   the strip-shaped or groove-shaped door guides (4) extending in the guide direction (4') are arranged on the side of the guide elements (9) that faces away from the pressing box (50).
5. Box baler according to any of the preceding claims,
   characterized in that
   the guide unit consisting of door guides (4) and guide elements (9) is designed to be self-locking against forces applied in the pressing direction (10').
6. Box baler according to any of the preceding claims,
   characterized in that

   - the door drive (6) comprises at least one working cylinder (7), in particular a hydraulic cylinder (7),

   - which in particular is arranged so as to extend in the guide direction (4') and, with the end thereof that faces away from the sliding door (5), is in particular arranged so as to be fixed, i.e. immovable, relative to the press housing (2).
7. Box baler according to any of the preceding claims,
   characterized in that
   a working cylinder (7) is arranged on both sides of the removal opening (52),
8. Box baler according to any of the preceding claims,
   characterized in that
   at least one position sensor (8) is provided, which

   - detects at least the end position of the sliding door (5) in the closed position,

   - preferably also detects the end position of the sliding door (5) in the open position, and

   - in particular detects the position of the sliding door (5) along its entire movement path.
9. Box baler according to any of the preceding claims,
   characterized in that

   - threading grooves (12) are provided in the contact surface (5a) of the sliding door (5) that faces the pressing box (50), which grooves extend transversely to the guide direction (4'), in particular horizontally, and the groove cross section (13) of which is delimited at the top and bottom by groove flanks (13b, c) extending toward the groove opening (13a),

   - the groove flanks (13b, c) extend from the groove opening (13a) at an acute angle (β1 or β2) to the opening plane (52"), which is in particular the transverse plane (10") to the longitudinal direction (10),

   - in particular the upper groove flank (13b) is at most as steep as the guide direction (4') and at least at an angle of 45° to the horizontal.
10. Box baler according to any of the preceding claims,
    characterized in that,
    when viewed in the longitudinal direction (10), the upper groove flank (13b) extends at least down to the free end of the lower groove flank (13c), in particular overlaps therewith.
11. Box baler according to any of the preceding claims,
    characterized in that

    - the acute angle (β2) of the upper groove flank (13b) to the opening plane (52") is equal to or greater than the angle (α),
    and/or

    - the acute angle (β1) of the lower groove edge (13c) to the opening plane (52") is equal to or greater than the angle (β2).
12. Box baler according to any of the preceding claims,
    characterized in that

    - a locking device (14) which acts in a form-fitting manner is provided for fixing the removal door (5) in the closed position, which locking device is in particular designed to be self-locking in the blocking position and

    - in particular is operatively connected to the door drive (6).
13. Method for operating a box baler (1) according to any of the preceding claims, for pressing loose material, preferably cardboard packaging (99), into bales (100),
    characterized in that
    when the removal door (5) is opened, the removal door (5) is moved in a straight guide direction (4').
14. Method according to any of the preceding claims,
    characterized in that
    the door plane (5") of the sliding door (5), which is defined by the contact surface (5a) facing the pressing box (50), is moved in a parallel position relative to the opening plane (52"), in particular exclusively in a parallel position relative thereto, when said door is opened or closed.
15. Method according to any of the preceding claims,
    characterized in that
    in order to open the removal door (5), only the door drive (6) is started, in particular no prior unlocking of a locking device (14) is carried out.

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