METHOD FOR CREATING AT LEAST ONE CLEARANCE IN A SHEATHING THAT CONSISTS OF SHRINK FILM AND SECURES A STACK OF ITEMS ARRANGED ON A PALLET, AND SHAPING APPARATUS FOR CARRYING OUT THE METHOD

Abstract

A method for creating at least one clearance in a sheathing consists of shrink film and secures a stack of items arranged on a pallet. The pallet has a top standing surface for the stack of items and a plurality of spaced bottom legs forming leg clearances. The sheathing engages under the legs in the region of the four outer edges of the pallet. At least one clearance is introduced into the sheathing region located between two legs. At least one clearance is intended to be created such that the sheathing region is first of all pulled away from the pallet in the still-hot state and is subsequently displaced upwards in the still-hot state, wherein the upwardly displaced sheathing region is then fixed in its upwardly displaced position by cooling. The invention also relates to a shaping apparatus for carrying out the method.

Claims

1. A method for creating at least one clearance in a sheathing comprising a shrink film for securing a stack of items arranged on a pallet, wherein the pallet has a top standing surface as a support for the stack of items and a plurality of bottom legs arranged in a manner spaced from one another to form leg clearances, and wherein the sheathing is arrayed along a bottom of the pallet and engages at least partially under the underside of the legs arranged in a region of four outer edges of the pallet, and wherein at least one of the leg clearances is located in a sheathing region located between two legs which are arranged in a row, the method comprising the following sequential steps a) providing a shaping apparatus comprising a plurality of pivotable fingers having ends for grasping the sheathing; b) shrinking the shrink film by heating to a hot state; c) positioning the fingers proximate the film in the sheathing region; d) pulling the sheathing region away from the pallet while the sheathing region is in the still-hot state by moving the fingers away from the pallet; e) displacing the sheathing region upwardly while the sheathing region is in the still-hot state by pivoting the fingers upwardly; and f) fixing the sheathing region in its upwardly displaced position by cooling.

2. The method of claim 1, wherein during the displacing step, the sheathing region is displaced upwardly to the top standing surface.

3. The method of claim 1, wherein during the displacing step, the sheathing region is displaced upwardly above the top standing surface.

4. The method of claim 1, wherein during the displacing step, the sheathing is pulled around respective lower inner edges of the two legs.

5. The method of claim 1, wherein the two legs are directly adjacent or are the outermost legs of the row.

6. The method of claim 1, wherein the sheathing is fixed to an underside of the two legs before and/or after the pulling step, and/or before and/or after the displacing step.

7. The method of claim 1, wherein the sheathing remains fixed to the underside of the two legs during the pulling and/or displacing step.

8. The method of claim 1, wherein a shrink hood is used as the sheathing.

9. The method of claim 1, wherein at least one subregion of the sheathing is fixed above the sheathing region from an outside in a horizontal direction with respect to the pallet.

10. The method of claim 1, wherein at least one subregion of the sheathing is fixed above the sheathing region from an outside in a horizontal direction with respect to the pallet by application of pressure during the pulling and/or displacing step.

11. The method of claim 1, further comprising the step of displacing the sheathing region in the direction of the pallet before the fixing step.

12. The method of claim 11, wherein the step of displacing the sheathing regions in the direction of the pallet involves pressing the sheathing region against at least one leg and/or the top standing surface of the pallet.

13. The method of claim 1, wherein the ends of the fingers comprises hooks for grasping and engaging the sheathing.

14. The method of claim 1, wherein the fingers are coated or provided with a non-stick and/or heat-resistant material.

15. A method for sheathing a pallet with at least one clearance, comprising the steps of: a) providing a sheathing apparatus including a shrink film positioning and heating assembly, and a shaping apparatus comprising a plurality of pivotable fingers having ends engageable with shrink film; b) providing a pallet having a top standing surface as a support for a stack of items and a plurality of bottom legs arranged in a manner spaced from one another to form leg clearances; c) providing a supply of shrink film; d) positioning the pallet in operable association with the shrink film so that the film is arrayed along a bottom of the pallet and engages at least partially under the underside of legs arranged in a region of four outer edges of the pallet, and wherein at least one of the leg clearances is located in a sheathing region located between two adjacent legs; e) shrinking the shrink film by heating to a hot state; f) positioning the fingers proximate the film in the sheathing region; g) pulling the sheathing region away from the pallet while the sheathing region is in the still-hot state by moving the fingers away from the pallet; h) displacing the sheathing region upwardly while the sheathing region is in the still-hot state by pivoting the fingers upwardly toward the pallet; and i) fixing the sheathing region in its upwardly displaced position in engagement with a bottom of the pallet by cooling and thereby creating a clearance.

16. The method of claim 15, wherein the ends of the pivotable fingers comprises hooks for grasping and engaging the sheathing.

17. The method of claim 15, further comprising the step of displacing the sheathing region in the direction of the pallet before the fixing step.

18. The method of claim 17, wherein the step of displacing the sheathing regions in the direction of the pallet involves pressing the sheathing region against at least one leg and/or the top standing surface of the pallet.

19. The method of claim 15, wherein the fingers are coated or provided with a non-stick and/or heat-resistant material.

20. The method of claim 15, wherein the fingers comprises a first finger and a second finger configured to engage the shrink film during the step of pulling the sheathing region away from the pallet, and a third finger configured to engage the shrink film during the step of pulling the sheathing region away from the pallet.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Exemplary embodiments of the invention that are illustrated in the drawings are explained in the following text. In the drawings:

[0042] FIG. 1 shows a shrink station conveyor having a total of two shaping apparatuses according to the invention of a shrink machine,

[0043] FIG. 2 shows a shaping apparatus in the flapped-in and non-raised state (rest position),

[0044] FIG. 3 shows the shaping apparatus according to FIG. 2 in the flapped-out and raised state,

[0045] FIG. 4 shows the shaping apparatus in the rest position,

[0046] FIG. 5 shows the moving of the shaping apparatus up to the pallet,

[0047] FIG. 6 shows the pulling-away movement of the shaping apparatus,

[0048] FIG. 7 shows the shaping of the sheathing region,

[0049] FIG. 8 shows the pressure exertion operation, and

[0050] FIG. 9 shows the sheathing in the shaped state.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

[0051] In all of the figures, corresponding reference signs are used for components that are identical or of the same type.

[0052] As illustrated in FIG. 1, the shrink machine comprises, inter alia, a shrink station conveyor, which is configured as a chain conveyor in the exemplary embodiment illustrated. The chain conveyor comprises five chain tracks 1 in the exemplary embodiment illustrated. The first and the second chain track 1 and the fourth and the fifth chain track 1 are each arranged close together at a slight distance apart. The distance between adjacent chain tracks 1 is adapted to the formats of the pallet 2 to be conveyed. By means of the chain conveyor, a pallet 2 which is positioned thereon and on the top of which a stack of items is arranged, can be moved in the conveying direction (arrows 3). Usually, the two longitudinal edges of the pallet 2 are oriented parallel to the conveying direction 3, while the two short end edges of the pallet 2 are oriented orthogonally to the conveying direction 3.

[0053] The shrink machine illustrated has a pallet lifting device 4 having lifting rams 5, a blower module 6 and a total of two shaping apparatuses 7. Not illustrated is the hot air frame, which is usually arranged centrally in the shrink machine. The two ends of the shrink station conveyor are connected via suitable connection points to the further conveying technology or to other machine constituents, such as a hood pull-over station, for example.

[0054] As can be gathered in particular from FIGS. 2 and 3, each pallet 2 side that is oriented orthogonally to the conveying direction 3 is assigned a shaping apparatus 7. Thus, one shaping apparatus 7 acts on the pallet 2 side that is oriented orthogonally to the conveying direction 3 and the other shaping apparatus 7 acts on the opposite other pallet 2 side that is oriented orthogonally to the conveying direction 3. Each shaping apparatus 7 consists of two halves, wherein one half is arranged in the region between one outer chain track 1 and the middle chain track 1 and the other half is arranged in the region between the middle chain track 1 and the other outer chain track 1. The two halves of the shaping apparatus 7 acting on one pallet 2 side are constructed in a mirror-inverted manner with respect to one another.

[0055] FIGS. 2 and 3 show a shaping apparatus 7 in detail. Each shaping apparatus 7 has a guide 8 and a drive (not illustrated). In this way, each shaping apparatus 7 can be displaced towards the pallet 2, and away again, from both sides as seen in the conveying direction 3. The guide 8 is arranged parallel to and beneath the middle chain track 1. In the exemplary embodiment illustrated, the guide 8 is configured as a ball rail system. However, other configurations are also possible. It is also conceivable for each of the two shaping apparatuses 7 to be assigned a separate guide 8. The shaping apparatus 7 interacting with the pallet 2 side that is oriented orthogonally to the conveying direction 3 can then be displaced separately from the shaping apparatus 7 cooperating with the other pallet 2 side that is oriented orthogonally to the conveying direction 3. For vertical lifting (arrow 9) for the shaping operation and for subsequent lowering after the shaping operation, a vertical guide having a drive is provided, which comprises a cylinder 10 in the exemplary embodiment illustrated. By means of the cylinder 10, the upper part of the shaping apparatus 7 is vertically displaceable. The vertical guide is configured as a ball rail system in the exemplary embodiment illustrated and is arranged next to the cylinder 10.

[0056] In order to compensate for angular deviations in the orientation of the pallet 2, each shaping apparatus 7 has an angle compensation element 11. The angle compensation element 11 is a vertically oriented peg on which the shaping apparatus 7 is arranged in a rotatably mounted manner. By means of a spring, the shaping apparatus 7 is kept in the position which corresponds to an optimal orientation of the pallet 2 on the chain tracks 1. In the optimal orientation, the side edges of the pallet 2 are oriented orthogonally or parallel to the conveying tracks 1.

[0057] When the shaping apparatus 7 is moved up to the pallet 2, the pallet 2 can be set down on the chain tracks 1 or raised by means of the lifting rams 5. If the pallet 2 has not been set down optimally on the chain tracks 1, the orientation of the pallet 2 is generally maintained when it is raised by way of the lifting rams 5. Any angular error would thus continue to exist.

[0058] When the shaping apparatus 7 is moved up to the pallet 2, the shaping apparatus 7 is oriented automatically with respect to the pallet 2. If the pallet 2 is not oriented optimally with respect to the chain tracks 1, when contact is made with the pallet 2, the shaping apparatus 7 is rotated by the pallet 2, counter to the force of the spring, into the position which corresponds to the orientation of the pallet 2.

[0059] In the rest state, as illustrated in FIG. 4, each shaping apparatus 7 has been lowered beneath the conveying level within the shrink station conveyor. In the exemplary embodiment illustrated, each half of a shaping apparatus 7 comprises three upwardly directed shaping fingers 12 and 12.1, the respective ends of which are configured as a tab and/or as a hook 24, 24.1. By means of the tabs and/or hooks 24, 24.1, a sheathing 17, as will be described in the following text, can be grasped, pulled out, shaped and additionally pressed against the side of the pallet 2 in particular while the still-hot sheathing 17 sets by cooling, as is illustrated in FIG. 8. The contact regions of the shaping fingers 12 and 12.1 can be coated or provided with a non-stick and/or heat-resistant material 27 at least in the regions that come into contact with the sheathing 17 and/or with the sheathing region 18.

[0060] As can be gathered in particular from FIGS. 5, 6 and 9, the non-stick and/or heat-resistant material 27 extends at least in the region of that surface of each hook 24.1 that faces towards and away from the pallet 2 and in the region of the side face of each shaping finger 12.1, said face pointing upwards in the position illustrated in FIGS. 5, 6 and 9. However, it is also quite possible for the non-stick and/or heat-resistant material 27 to also extend at least in the region of that surface of each hook 24 that faces away from the pallet 2 and in the region of the side face of each shaping finger 12, said face pointing upwards in the position illustrated in FIGS. 5 and 6.

[0061] Each half of the shaping apparatus 7 has two shaping fingers 12 which are displaceable in the horizontal direction in order to pull the sheathing region 18 away from the pallet 2. The third shaping finger of each half, namely the shaping finger 12.1, is mounted in a pivotable manner, as can be seen for example in FIGS. 3 and 9. To this end, the shaping finger 12.1 is assigned a drive 13 such that the shaping finger 12.1 is displaceable about the pivot pin 14. As can be gathered from FIGS. 2 and 3, the shaping finger 12.1 is configured in such a way with respect to the two shaping fingers 12 which are assigned to this shaping finger 12.1 that this shaping finger 12.1 is not in contact with the sheathing region 18 during the pulling away operation.

[0062] Each movable shaping finger 12.1 is assigned a stop 15 which allows automatic fitting into the corners of the leg clearances 16 of the pallet 2, regardless of the format of the pallet 2. During the pivoting movement, the stop 15 projects into the contour of the pallet 2, i.e. into the leg clearance 16. If the stop 15 comes into contact with the leg of the leg clearance 16 during the pivoting of the shaping finger 12.1, the pivoting movement is stopped.

[0063] In FIGS. 4 to 9, the profile of the sheathing 17 and of the sheathing region 18 is indicated by dashed lines. The sheathing region 18 is understood as being that region of the sheathing 17 which is located in front of the leg clearance 16 of the pallet 2 without the method according to the invention being carried out, said leg clearance 16 being intended to be made accessible by a clearance in the sheathing 17. For clearer illustration, the stack of items arranged on the pallet 2 is not illustrated. The vertical extent of the sheathing 17 upwardly beyond the pallet 2 is therefore only indicated. The shrink station conveyor is also not illustrated.

[0064] FIGS. 4 to 9 illustrate a pallet 2 which has three rows consisting of in each case three legs 19, 20, 21 of block-like design, wherein the three legs 19 and 20 and 21 in a row are connected together on the underside by a bottom board 22. The sheathing 17 engages in this respect around the underside of the two outermost bottom boards 22 and the two outermost ends of the bottom board 22 connecting the legs 20. On the top side, the pallet 2 has a standing surface 23 which consists of five top boards. It is also possible for transverse boards to be arranged between the legs 19, 20, 21 and the standing surface 23. For clarity, the above-described components of the pallet 2 are labelled only in FIG. 4.

[0065] In the exemplary embodiment illustrated in FIGS. 4 to 9, the two legs are the outermost legs 19, 21. In this respect, the sheathing region 18 to be displaced upwards extends over the middle leg 20 such that both the leg clearance 16 between the two legs 19, 20 and the leg clearance 16 between the two legs 20, 21 is completely free of the sheathing region 18 after the method according to the invention has been carried out.

[0066] As already described above, each shaping apparatus 7 consists of two halves, wherein each half is assigned to a leg clearance 16 and has the above-described two shaping fingers 12 and the shaping finger 12.1 to create a clearance. A view of the short side of the pallet 2 (as seen in the conveying direction 3) is illustrated in the respective left-hand half of FIGS. 4 to 9 and a view of the long side of the pallet 2 (parallel to the conveying direction 3) is illustrated in the right-hand half of FIGS. 4 to 9.

[0067] In the method illustrated in the figures, first of all a pallet 2 is conveyed into the shrink machine and stopped. Subsequently, the pallet 2 is raised for undershrinking by means of the pallet lifting device 4, which has lifting rams 5 that are displaceable in a manner corresponding to the size of the pallet 2. After raising, the undershrinking of the lower periphery of the sheathing 17 is carried out. In the meantime, the two shaping apparatuses 7 are located outside the heating region in their rest position, as is illustrated in FIG. 4.

[0068] After completion of undershrinking, the pallet 2 is lowered to a lower height, but not set down. If desired, the undershrink created in the raised state can additionally be secured at the outer periphery of the pallet 2 by means of pressure rams 26. By means of the pressure rams 26, which are arranged between the first and the second chain track 1 and the fourth and the fifth chain track 1, respectively, the lower periphery of the sheathing 17 and thus the undershrink is pressed against the underside of the pallet 2 in the region of the sides oriented parallel to the conveying direction 3. For the movement of the pressure rams 26, a mechanical coupling can be provided for example between the pressure rams 26 and the movement of the pallet lifting device 4. Alternatively, the pressure rams 26 can also be embodied in a power-driven manner.

[0069] Subsequently, the shaping apparatuses 2 are moved up to the pallet 2 from both sides. This takes place on the one hand by a horizontal movement (arrow 3). Furthermore, the shaping apparatuses 7 are raised in the direction of the arrow 9. This is illustrated in FIG. 5. During the horizontal displacement, the shaping fingers 12, 12.1 are still located beneath the plane of the bottom boards 22 of the pallet 2, such that the shaping fingers 12, 12.1 can be moved within the contour of the sheathing 17.

[0070] The shrinking process can in this case be continued by moving the heating frame vertically upwards. The shaping apparatuses 7 moved up to the pallet 2 are therefore not located in the direct heating zone of the hot-air frame in their position moved up to the pallet 2.

[0071] In FIG. 6, the shaping fingers 12, 12.1 have already been raised to such an extent that the hooks 24, 24.1 are located above the lower periphery of the sheathing 17 and thus within the sheathing 17, such that the hooks 24, 24.1 of the shaping fingers 12, 12.1 engage behind the sheathing 17 that is still hot and soft from undershrinking. The shaping apparatus 7 and thus the shaping fingers 12, 12.1 are subsequently moved away from the pallet 2 by the drive assigned to the guide 8, such that, as a result, the sheathing region 18 grasped by the hooks 24, 24.1 is pulled away from the pallet 2 in the still-hot state. This is illustrated in FIG. 6.

[0072] Subsequently, the sheathing region 18 is displaced upwards in the still-hot state. This is illustrated in FIG. 7. To this end, the shaping fingers 12.1 having the hooks 24.1 are pivoted upwards and outwards in a pivoting movement about their pivot pins 14. In this case, the sheathing 17 is pulled around the respective lower inner edge of the two legs 19, 21, i.e. around the right-hand lower inner edge of the leg 19 and around the left-hand lower inner edge of the leg 21, in the exemplary embodiment illustrated.

[0073] During this pivoting movement, the sheathing region 18 is also pulled along and pulled upwards. The sheathing region 18 is, in the process, displaced outwardly in the direction of the outwardly directed corner of each leg clearance 16. By way of the two pivoted-up shaping fingers 12.1 of the shaping apparatus 7 acting on a common side of the pallet 2, the sheathing region 18 is stretched in this way. In order to limit the pivoting movement, each shaping finger 24.1 is assigned a stop 15. Since the stop 15 projects into the contour of the pallet 2, i.e. into the leg clearance 16, at least with its front end, the stop 15 comes into contact with the leg of the leg clearance 16 while the shaping finger 12.1 is being pivoted, such that the pivoting movement is stopped upon contact.

[0074] The shaping fingers 12, 12.1 having the respectively associated tab 24, 24.1 are in this case located outside the contour of the pallet 2, i.e. at a distance from the outer side of the leg 19, 20, 21, such that the deformed sheathing region 18 is laid from the outside around the leg clearance 16 in question and, in the exemplary embodiment illustrated in FIGS. 4 to 9, around the two leg clearances 16. In the stretched state, each shaping apparatus 7 is displaced horizontally again in the direction of the pallet 2 side oriented orthogonally to the conveying direction 3 of the pallet 2. Since the two shaping fingers 12.1 of a shaping apparatus 7 are longer than the four shaping fingers 12 of this shaping apparatus 7 and thus protrude with respect to the shaping fingers 12, as seen in the direction of the pallet 2, the shaping fingers 12.1 come into contact, as a result of the horizontal movement, with the standing surface 23 or the outer side of the leg 19, 20, 21 located in the travel path, with their hook 24.1 face that faces the pallet 2. To this end, the face of each hook 24.1 that faces the pallet 2 is, inter alia, preferably coated with the non-stick and/or heat-resistant material 27, as described above with respect to FIGS. 5 and 6.

[0075] By way of the hooks 24.1, the not-yet cooled double-ply sheathing 17 is pressed against the standing surface 23 or the outer side of the leg 19, 20, 21 of the pallet 2, as is illustrated in FIG. 8. As a result of the horizontal movement, the stretched sheathing region 18 and the adjoining sheathing 17 are displaced closer to the pallet 2 again and are connected on cooling to the sheathing 17 laid around the leg 19, 20, 21, before said sheathing 17 cures, such that additional stabilization is achieved as a result by the sheathing region 18 connected to the adjoining sheathing 17 and/or the pallet 2. The angle compensation element 11 acts during this pressure exertion operation.

[0076] In the taut position, the sheathing region 18 then sets upon cooling. As a result, the leg clearance 16 in question is durably completely free of the sheathing region 18. As a result of the stretching, the leg clearances 16 under the pallet 2 are completely freed.

[0077] If desired, the sheathing 17 can be additionally fixed on the two sides to be shaped, which, in the exemplary embodiment illustrated, are the short end sides of the pallet 2, by a fixing element 25 that is displaceable in the direction of the pallet 2 and is configured in the form of a pin, while the sheathing region 18 is being pulled away outwards and/or while the sheathing region 18 is being displaced upwards. By means of the fixing element 25, the sheathing 17 is pressed against the pallet 2. As a result of this end-side fixing, undesired half-moon formation is avoided.

[0078] In the exemplary embodiment illustrated, the middle chain track 1 consists of two spaced-apart chains that extend in parallel. The fixing element 25 is located between the two chains of the middle chain track 1. Thus, the fixing element 25 acts approximately at the level of the standing surface 23 or a little lower, in the middle of the pallet 2. In the exemplary embodiment illustrated, the fixing element 25 is displaced by a pivoting movement from its rest position illustrated in FIG. 1, in which it does not project out of the plane of the chain conveyor, into its fixing position. The pivot pin and the associated drive of the fixing element 25 can be constituent parts of the chain conveyor. However, it is also quite possible for the pivot pin and the associated drive of the fixing element 25 to be constituent parts of the shaping apparatus 7.

[0079] Alternatively, the fixing element 25 can be located laterally at a short distance from the middle chain track 1. It does not then act exactly on the middle of the pallet 2, if the pivoting plane of the fixing element 25 is parallel to the axis of the chain track 1 and the conveying direction 3. However, if the pivoting plane of the fixing element 25 is not parallel to the axis of the chain track 1 and the conveying direction 3, contact is also possible in the middle of the pallet 2 in this case. Regardless of the orientation of the pivoting plane of the fixing element 25, the fixing element 25 acts on the pallet 2 approximately at the level of the standing surface 23 or a little lower.

[0080] It is of course also possible for a respective fixing element 25 to be located on each side of the middle chain track 1, such that the sheathing 17 is pressed against the pallet 2 at two locations in this way.

[0081] After completion of the shrinking process, the forming fingers 12.1 are pivoted back downwards again. This situation is illustrated in FIG. 9. As can be gathered from FIG. 9, the shaping apparatuses 7 have already been lowered again and moved outwards out of the heating region of the shrink machine in this illustration. If pressure rams 26 have been used, these are released when the pallet 2 is set down and the pallet 2 can subsequently be conveyed away.

[0082] Of course, it is also possible for only one shaping apparatus 7 to be provided, such that in this respect a clearance can be introduced into the sheathing 17 only on one side.