EP0437760B1 - Device for separating (intermediate) layers from piles of stacked products - Google Patents

Description

The invention relates to a device for lifting sheet-like objects, in particular sheet-shaped (intermediate) layers from a base, for. B. of (cutting) stacks of a pallet or the like, by means of suction lifter, which can be placed with suction holes on the top of the (intermediate) layer.

Many objects are stacked in layers on pallets, a thin intermediate layer or a sheet-shaped intermediate layer being arranged between the individual layers. This can consist of cardboard, in particular corrugated cardboard, but also of plastic.

The stacked layers can be individual objects arranged side by side in each layer, but also (small) stacks of sheet-like objects. An important example is the arrangement of prefabricated blanks from thin cardboard for the production of packs, in particular (cigarette) hinged boxes. The specially designed blanks are in stacks of z. B. summarized a thousand blanks and placed side by side as a stacked layer on a pallet for transport and storage. The already mentioned intermediate layers made of cardboard or the like are located between a plurality of stack layers formed one above the other.

Automatically working pallet unloaders are usually used when unloading the pallets on site. These can be designed in different ways. In any case, the problem arises of removing the intermediate layers after clearing a stack layer.

Up to now, the intermediate layers have often been lifted by hand from the stack layers of the pallet. However, automatically operating pallet unloaders are known in the packaging industry, which are equipped with a suction lifter for grasping the top of stacked objects.

From GB-A-966 957 a device is also known which is equipped with two suction lifters for gripping the intermediate layers and the tops of relatively difficult and one-piece stacked objects.

In the (manual or mechanical) removal of the intermediate layers, however, there has hitherto been a risk that the objects of the stacked layer will be shifted against one another. This applies in particular if the stack layer consists of cut stacks because these have a low weight and can be easily shifted against each other. There is also the danger that the upper blanks of the blank stack will be lifted off with the intermediate layer.

Proceeding from this, the object of the invention is to further mechanize and simplify the unloading of pallets or the like, but in particular the objects of the stacked layer when an intermediate layer is lifted off secure against displacement.

To achieve this object, the device according to the invention is characterized in that the suction lifter (suction plate) has support members (hold-down devices) which pass through openings (recesses) in the intermediate layer when the suction lifter is placed on the intermediate layer and adhere to the layer underneath during the lifting of the intermediate layer support lying objects (blank stack).

According to the invention, the objects of the stack layer, in particular a plurality of stacked blanks arranged next to one another, are mechanically secured against displacement during the initial phase of lifting an intermediate layer. Hold-down devices are provided for this purpose, which are supported with a certain pressure on the objects or stacks of blanks and thereby fix them, while at the same time the intermediate layer is lifted from the stack position by the suction lifter moving upward.

According to the invention, the intermediate layer is designed in a special way, namely provided with openings which allow the hold-down devices to pass through to the object (stack of blanks).

The suction lifter can be designed such that a number of suction lifters corresponding to the number of objects is provided on the underside. However, the suction lifters can also be designed, dimensioned and arranged in such a way that, when the suction lifter is lowered, each hold-down device detects several objects or stacks of blanks on the upper side and fixes them by pressure transmission. In particular, hold-downs with circular stamp plates on pressure rams can each be in the area of the meeting corners of a plurality of blank stacks, e.g. B. of four adjacent blank stacks.

The hold-down devices are movably mounted on the suction lifter, namely movable up and down. The hold-down devices are still spring-loaded in the direction of the extended position. It is thereby achieved that during the initial phase of the upward movement of the suction lifter - with the intermediate layer being carried - the hold-down devices remain in the holding position under contact with the objects. When the suction lifter continues to move, the extended hold-down devices are also lifted.

The invention is also concerned with securing the objects of a stack in the transverse direction. This applies in particular to the mentioned stack of blanks for (cigarette) folding boxes. These cuts have a special, characteristic geometric shape. Because of the same, specially formed, namely angular or V-shaped cavities arise between adjacent blank stacks. In order to ensure the exact stack formation of the blank stacks, guide or support members of the suction lifter enter the cavities mentioned, namely elongated profile pieces which are adapted in cross section to that of the cavities.

According to the invention, the profile pieces are arranged on the underside of the hold-down devices and are therefore threaded into the cavities between the intermediate stacks when the suction lifter is lowered. The dimension of the profile pieces is such that when the suction lifter is lowered, the profile pieces extend over the full height of a blank stack or enter the recess of an intermediate layer underneath with one end. As a result, the blank stacks are aligned or supported over the entire height.

Further features of the invention relate to the design of the suction lifter and a complete device for automatically picking up and depositing the intermediate layers.

Fig. 1

Einen Zuschnitt für eine Klappschachtel in ausgebreitetem Zustand,

Fig. 2

einen Teil einer Vorrichtung zum Entladen von Paletten in schematischer Seitenansicht,

Fig. 3

eine Grundrißdarstellung zu Fig. 2,

Fig. 4

eine Einzelheit eines Saughebers mit Stapellagen einer Palette in Seitenansicht bzw. im Vertikalschnitt,

Fig. 5

einen Ausschnitt des Saughebers in einer Darstellung entsprechend Fig. 4 - bei vergrößertem Maßstab - in einer anderen Bewegungsphase,

Fig. 6

eine Darstellung entsprechend Fig. 5 während des Abhebens einer Zwischenlage durch den Saugheber,

Fig. 7

einen Horizontalschnitt bzw. eine Draufsicht in der Ebene VII - VII der Fig. 4.

An embodiment of the invention is explained below with reference to the drawings. It shows:

Fig. 1

A blank for a hinged box when it is spread out,

Fig. 2

part of a device for unloading pallets in a schematic side view,

Fig. 3

2 shows a plan view of FIG. 2,

Fig. 4

a detail of a suction lifter with stack layers of a pallet in side view or in vertical section,

Fig. 5

4 shows a section of the suction lifter in a representation corresponding to FIG. 4 - on an enlarged scale - in another phase of movement,

Fig. 6

5 during the lifting of an intermediate layer by the suction lifter,

Fig. 7

a horizontal section or a plan view in the plane VII - VII of FIG. 4th

The embodiment shown in the drawings deals with the unloading of pallets 10. On this, layers of objects are arranged, namely stack layers 11. In the present embodiment, each stack layer 11 consists of a plurality of stacked blanks 12 of the same type aligned in longitudinal rows and transverse rows Size and shape. There is an intermediate layer 13 between the stacking layers 11 lying one above the other. This can consist, for example, of (corrugated) cardboard.

When the pallet 10 is unloaded, the stack layers 11 are cleared one after the other. In the present game Ausführungsbei cross rows 14 from blank stacks 12 are pushed as a unit from the underlying intermediate layer 13. The transverse row 14 is completely gripped by a slide 15.

After clearing a stack layer 11, the intermediate layer 13 must be removed so that the stack layer 11 underneath can also be cleared.

A suction lifter 16 is used for automatically removing the intermediate layers 13. This consists of a suction plate 17, approximately the size of the pallet or an intermediate layer 13. The suction plate 17 is lowered onto the intermediate layer 13 in order to lift it off. The intermediate layer 13 is fixed on the underside of the suction plate 17 via suction bores 18 in the suction plate 17 and can be removed with the latter. The suction plate 17 is designed as a hollow body with a continuous vacuum chamber 19. The suction bores 18 are formed in a lower plate wall 20, specifically in a distribution sufficient to cover the intermediate layer 13. The suction plate 17 or the vacuum chamber 19 is connected via a suction line 21 to a vacuum source (not shown).

When an intermediate layer 13 is lifted off a stack layer 11, a relative displacement of the blank stacks 12 lying underneath should be avoided. For this purpose, the blank stacks 12 are temporarily fixed underneath an intermediate layer 13 to be lifted off during the lifting process.

For this purpose, support members or hold-down devices 22 are arranged on the suction plate 17. These are lowered onto the intermediate layer 13 with the suction plate 17. The intermediate layer 13 is provided in the area of the hold-down device 22 with openings or recesses 23. These are arranged and dimensioned so that the hold-down 22 without constraint through the recesses 23 can pass through and thereby come to rest on the top of the blank stack 12.

The hold-down devices 22 are designed as pressure stamps with a circular stamp plate 24 in the present case, which passes through the recess 23 and receives contact with the top of the blank stack 12. The stamp plate 24 is arranged on a pressure tappet 25 which is mounted in the suction plate 17 such that it can be moved, namely moved up and down. For this purpose, the suction plate 17 is provided with a plurality of tappet housings 26. These are inserted into the suction plate 17 like cylinders. The pressure tappet 25 is slidably mounted within the tappet housing 26 and secured against sliding out by a collar 27 at the free end of the pressure tappet 25. The pressure ram 25 is also guided in a passage opening 28 of the plate wall 20.

The hold-down devices 22 are constantly or at least when the suction plate 17 is lowered onto the intermediate layer 13 in the direction of the extended position (FIG. 2, FIG. 4), namely by a compression spring 29. This is supported and supported within the tappet housing 26 on the free end of the pressure ram 25 (on the collar 27).

To accommodate an intermediate layer 13, the suction lifter 16 with the suction plate 11 is lowered onto the intermediate layer 13 when the hold-down devices 22 are extended, namely until the plate wall 20 abuts the intermediate layer 13. During the last phase of the lowering movement, the pressure tappets 25 are pressed together by compressing the compression spring 29 moved into the plunger housing 26 until the stamp plate 24 rests on the underside of the plate wall 20. In this position (FIG. 5), the stamp plate 24 lies within the significantly larger recess 23. The thickness of the stamp plate 24 corresponds in this case to the thickness of the intermediate layer 13. With the pressure of the compression spring 29, the hold-down device 22 with the stamp plate 24 lies on the Blank stack 12 on.

These are pressed down and thus fixed.

By connecting to the vacuum shaft 18 vacuum is generated in the area of the suction bores. The intermediate layer 13 lies against the suction plate 17 and is now raised with it.

During a first phase of the lifting movement, the hold-down devices 22 protruding through the recess 23 remain in the system on the blank stacks 12 and fix them. The plungers 25 increasingly move out of the plunger housing 26 until the collar 27 abuts the plunger housing 26 in the area of the passage opening 28. The hold-down devices 22 are now also carried along during the further stroke movement. Their function is now fulfilled, since the intermediate layer 13 is free of the blank stacks 12 underneath.

The hold-down device 22 can be arranged such that a separate hold-down device is assigned to each blank stack 12 of the stacked layer 11. In the present exemplary embodiment of the arrangement of blank stacks 12 in longitudinal rows and transverse rows 14, a hold-down device 22 is arranged in the joint area of four blank stacks 12, that is, where the corners of four blank stacks meet. As a result, each blank stack 12 is gripped by a hold-down device 22 at all four corners. Correspondingly, the recesses 23 are arranged in the intermediate layer 13.

As a further measure to ensure the exact relative position of the blank stacks 12 and of blanks 30 thereof within the blank stacks 12, guide members are arranged on the suction lifter 16, namely upright profile pieces 31. These are of angular or V-shaped cross-section. In the present exemplary embodiment, such a profile piece 31 is arranged on the underside of each hold-down device 22.

The profile pieces 31 positively enter into cavities 32 which are formed between adjacent blank stacks 12. The cavities 32 also have a V-shaped cross section, so that the profile pieces 31 enter these cavities 32 in a suitable and thereby stabilizing manner for the exact alignment of the blank stacks 12.

The special shape of the cavities 32 is given in the present case by the shape of the blanks 30 from which the blank stacks 12 are formed. These are blanks 30 for folding boxes for holding cigarettes. Typical of the design of such blanks 30 is the formation of a trapezoidal depression 33 at one end of the blank 30. The depression 33 results from the side tab 34 with triangular end regions or with triangular gussets 35 over a front wall 36 of the package to be formed from the blank 30 stick out.

On the opposite side of the blank 30 there are parts for the formation of a lid, namely a protruding inner flap 37 of the lid, which has a significantly smaller width than the blank in the rest. Furthermore, trapezoidal cover side tabs 38 with obliquely directed shoulders 39 are located in this area.

In a sensible arrangement of blank stacks 12 from such blanks 30, the inner lid flaps 37 of one blank stack 12 enter the recesses 33 of an adjacent blank stack. The shoulders 39 are arranged adjacent to the oblique edges of the triangular gusset 35. The result is an inclined partial cavity which, together with a partial cavity of two adjacent blank stacks 12, results in the (overall) cavity which is V-shaped in cross section.

The profile pieces 31 are dimensioned such that they capture the full height of the cavity 32 when the suction lifter 16 is lowered or when the suction plate 17 rests on the intermediate layer 13 or protrude slightly into the recess 23 of an intermediate layer 13 (FIG. 4). When lifting the suction plate 12, the profile pieces 31 are pulled out of the cavities 32 again.

The suction lifter 16 formed in the manner described can be arranged on a suitable device for carrying out the lifting and further conveying movements, for. B. on a cantilever arm of a palletizer. In the present exemplary embodiment, a linear movement of the suction lifter 16 is provided above the pallet 10 or the stack layers 11.

For this purpose, a support frame 40 is provided from upright supports 41 and a support frame 42 arranged at the upper ends thereof and extending in the horizontal plane. The support frame designed in this way has a rectangular plan.

Cross members 43, 44 of the support frame 42 are connected to one another by guide rails 45, 46. These are arranged laterally and parallel to longitudinal spars 47, 48.

On the guide rails 45, 46, a cross member 49 with sliders 50, 51 is displaceable at the ends. The cross member 49 is moved here by a cable drive, which consists of a pull cable 52 with the ends attached to the cross member 49. This runs over a drive roller 53 on one cross-member 43 and over a deflection roller 54 on the opposite cross-member 44. The drive roller 53 is driven by a motor 55, alternatively in one or the other direction of rotation, so that the cross member 49 correspondingly and can move.

The suction lifter 16 is attached to the cross member 49. In the present embodiment, two support rods 56, 57 are attached to the top of the suction plate 17. These pass through the cross member 49 and are each held in a bearing sleeve 58 for performing sliding movements. On the top of the cross member 49 there is also a pressure medium cylinder 59 for carrying out the up and down movements of the suction lifter 16 via the support rods 56, 57.

By means of the actuating device described, the suction lifter 16 is moved back and forth in the raised position between a depositing position (FIG. 2) and a receiving position. In the set-down position, the suction lifter 16 is located above an empty pallet 60 on which the intermediate layers 13 are placed. In the receiving position, the suction lifter 16 is located above the pallet 10.

Claims (12)

1. Apparatus for lifting off sheet-like articles, especially (intermediate) layers (13) in sheet form, from a base, for example from (blank) stacks (12) of a pallet or the like, by means of a suction lifter (16) which can be placed with suction bores onto the top side of the (intermediate) layer (13), characterized in that the suction lifter (16) has supporting members (holding-down devices 22) which, when the suction lifter (16) is placed onto the (intermediate) layer (13), pass through orifices (recesses 23) in the (intermediate) layer (13) and which, during the lifting off of the (intermediate) layer (13) by the suction lifter (16), are supported on articles (blank stacks 12) located underneath.
2. Apparatus according to Claim 1, characterized in that the intermediate layer (13) has recesses (23) which are distributed in a grid-like manner and which are clearly larger than a part of the holding-down device (22) passing through the recess (23).
3. Apparatus according to Claim 1 or 2, characterized in that the holding-down devices (22) are arranged on the suction lifter (16) so as to be movable (up and down) and are loaded in such a way that, during a first phase of the upward movement of the suction lifter (16) together with the intermediate layer (13), the holding-down devices (22) bear with their ends, especially with a ram plate (24), on the articles (blank stack 12) located underneath.
4. Apparatus according to Claim 3, characterized in that the holding-down devices (22) are of piston-like design and are each displaceably mounted by means of a shank (pressure plunger 25) in a cylinder-like plunger housing (26) of the suction lifter (16) and are loaded in the direction of extension, preferably by a compression spring (29).
5. Apparatus according to Claim 3, characterized in that, in the retracted position, as a result of the placing of the suction lifter (16) onto the intermediate layer (13), the holding-down devices (22) bear with the ram plate (24) on the underside of the suction lifter (16), the ram plate (24) projecting into the recess (23) of the intermediate layer (13).
6. Apparatus according to Claim 1 and one or more of the further claims, characterized in that the recesses (23) in the intermediate layer (13) and correspondingly the holding-down devices (22) are distributed in such a way that four blank stacks (12) at a time are loaded, underneath the intermediate layer (13) to be lifted off, by a holding-down device (22) or by its ram plate (24) in the region of corners facing one another.
7. Apparatus according to Claim 1 and one or more of the further claims, characterized in that there are arranged on the underside of the suction lifter (16) bar-shaped elongate guide members, particularly profiled pieces (21) which, during the lowering of the suction lifter (16) onto a group of articles, especially blank stacks (12), arranged next to one another in a stack layer (11), penetrate positively into cavities (32) formed between these.
8. Apparatus according to Claim 7 and one or more of the further claims, characterized in that the profiled pieces (31) are attached to the underside of the suction lifter (16), especially to the underside of the holding-down devices (22), and pass through the recesses (23) formed in the intermediate layer (13).
9. Apparatus according to Claim 7, characterized in that the profiled pieces (31) are of angular (V-shaped) cross-section and penetrate positively into correspondingly shaped cavities (32) between adjacent blank stacks (12) consisting of blanks for hinge-lid packs.
10. Apparatus according to Claim 7, characterized in that the length of the profiled pieces (31) is slightly larger than the height of a blank stack (12), the lower end of the profiled piece (31) penetrating into a recess (23) of the intermediate layer (13) located underneath it.
11. Apparatus according to Claim 1 and one or more of the further claims, characterized in that the suction lifter (16) has a suction plate (17) which is movable up and down and has a continuous vacuum chamber (19) and in which the plunger housings (26) of the holding-down devices (22) are arranged.
12. Apparatus according to Claim 1 and one or more of the further claims, characterized in that the suction lifter (16) is mounted so as to be movable up and down on a crossmember (49) which is itself movable in a frame-like supporting stand (40) on lateral guide rails (45, 46) by means of a rope drive (pull rope 52).

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