METHOD AND APPARATUS FOR SHRINKING A HEAT-SHRINK FILM APPLIED AROUND AN, IN PARTICULAR PALLETIZED, GOODS STACK

Abstract

The invention relates to a shrinking a heat-shrink film around palletized goods. The heat-shrink film projects beyond the top edge of the goods stack. Firstly the heat-shrink film is shrunk in the region of a first lateral surface sub-region of the four lateral surface sub-regions of the goods stack. The shrinkage direction is from bottom to top and then the shrinkage direction is changed 90°. In a further step either, the shrinkage direction is changed a further 90°, the heat-shrink film is shrunk from top to bottom in the region of that lateral surface sub-region of the goods stack, or, the shrinkage direction is changed a further 90°, and the heat-shrink film is preheated from top to bottom in the region of that lateral surface sub-region which is located oppositely from the first lateral surface sub-region, and is then shrunk in the opposite direction from bottom to top.

Claims

1. A method for shrinking a heat-shrink film (4) applied around an, in particular palletized, goods stack (2) that comprises a bottom surface, a cover surface, and a circumferential lateral surface that is made up of four lateral surface sub-regions, with at least one heating device (5) for shrinking the heat-shrink film (4) by heating, the heat-shrink film (4) covering the lateral surface of the goods stack (2) at least in its top region, preferably the entire height of the lateral surface, and the heat-shrink film (4) projecting at the top, at least with a heat-shrink film sub-region (4a), beyond the top edge of the goods stack (2) for formation of a top shrink, wherein firstly the heat-shrink film (4) is shrunk in the region of a first lateral surface sub-region of the four lateral surface sub-regions of the goods stack (2), the shrinkage direction (12) being from bottom to top; then, the shrinkage direction (12) being changed approximately 90°, that heat-shrink film sub-region (4a) of the heat-shrink film (4) which projects at the top beyond the top edge of the goods stack (2) is shrunk, beginning from the top edge of the first lateral surface sub-region along the cover surface; and in a further step either, the shrinkage direction (12) being changed approximately a further 90°, the heat-shrink film (4) is shrunk from top to bottom in the region of that lateral surface sub-region of the goods stack (2) which is located oppositely from the first lateral surface sub-region, or, the shrinkage direction (12) being changed approximately a further 90°, the heat-shrink film (4) is preheated from top to bottom in the region of that lateral surface sub-region of the goods stack (2) which is located oppositely from the first lateral surface sub-region, and is then shrunk in the opposite direction from bottom to top.

2. The method according to claim 1, wherein the goods stack (2) is stationary during shrinking; and at least one, preferably vertically adjustable, heating device (5) is guided along the goods stack (2).

3. The method according to claim 1, wherein in the context of shrinkage, the goods stack (2) is moved in a conveying direction (3) by means of a conveying device (1) whose conveying speed is preferably regulatable, the first of the four lateral surface sub-regions of the goods stack (2) facing in the conveying direction (3); and at least one heating device (5) is arranged pivotably around an axis (6) oriented parallel to its lengthwise dimension but in stationary fashion in relation to the conveying direction (3).

4. The method according to claim 1, wherein in the context of the relative displacement between the goods stack (2) and at least one, preferably vertically adjustable, heating device (5) in the context of shrinkage, a narrow marginal region (13) of the heat-shrink film (4) on at least one of the two lateral surface sub-regions oriented parallel to the shrinkage direction (12) during shrinking of the cover surface, which region adjoins the edge to the first lateral surface sub-region of the goods stack (2) and/or adjoins the edge to the top side of the goods stack (2) and/or adjoins the edge to that lateral surface sub-region of the goods stack (2) which is located oppositely from the first lateral surface sub-region, is additionally shrunk.

5. The method according to claim 1, wherein the heat-shrink film (4) is embodied as a heat-shrink film wrapper.

6. The method according to claim 5, wherein a cover sheet film, preferably projecting beyond at least one lateral edge of the cover surface of the goods stack (2), is arranged on the top side of the goods stack (2), which film is heat-sealed to that heat-shrink film sub-region (4a) of the heat-shrink film (4), embodied as a heat-shrink film wrapper, which projects beyond the top edge of the goods stack (2).

7. The method according to claim 6, wherein simultaneously with or after shrinking of that heat-shrink film sub-region (4a) of the heat-shrink film (4) which projects at the top beyond the top edge of the goods stack (2), the cover sheet film is also at least partly shrunk in the region that is not in contact with the heat-shrink film sub-region (4a) applied as a consequence of shrinking.

8. The method according to claim 1, wherein the heat-shrink film (4) is embodied as a heat-shrink film hood pulled over the goods stack (2).

9. The method according to claim 1, wherein at least during shrinking of the first of the four lateral surface sub-regions, the goods stack (2) is at least partly, preferably completely, covered at the top by a planar thermal conduction and/or thermal reflection device (7) arranged above the goods stack (2) at a distance from the cover surface and oriented parallel thereto.

10. The method according to claim 1, wherein at least during shrinking of the cover surface, the goods stack (2) is at least partly, preferably completely, covered at the top by a planar thermal conduction and/or thermal reflection device (7) arranged above the goods stack (2) at a distance from the cover surface and oriented parallel thereto.

11. The method according to claim 1, wherein the heat-shrink film (4) is preheated in the region of the first lateral surface sub-region, preferably from top to bottom, prior to shrinking.

12. An apparatus for shrinking a heat-shrink film (4) applied around an, in particular palletized, goods stack (2) that comprises a bottom surface, a cover surface, and a circumferential lateral surface that is made up of four lateral surface sub-regions, having at least one heating device (5) for shrinking the heat-shrink film (4) by heating, the heat-shrink film (4) covering the lateral surface of the goods stack (2) at least in its top region, preferably the entire height of the lateral surface, and the heat-shrink film (4) projecting at the top, at least with a heat-shrink film sub-region (4a), beyond the top edge of the goods stack (2) for formation of a top shrink, wherein the apparatus encompasses a conveying device (1) for moving the goods stack (2) in a conveying direction (3) during shrinking; and for heat impingement, at least one heating device (5) is embodied in oblong fashion and is oriented above the conveying device (1) horizontally and orthogonally to the conveying direction (3), and the lengthwise dimension of the heating device (5) extends at least approximately over the width of the goods stack (2), the heating device (5) being arranged vertically adjustably and mounted pivotably around an axis (6) oriented parallel to its lengthwise dimension, and furthermore a control system being provided by means of which firstly the heat-shrink film (4) is shrunk in the region of a first lateral surface sub-region of the four lateral surface sub-regions of the goods stack (2), the shrinkage direction (12) being from bottom to top, then, the shrinkage direction (12) being changed approximately 90°, that heat-shrink film sub-region (4a) of the heat-shrink film (4) which projects at the top beyond the top edge of the goods stack (2) is shrunk, beginning from the top edge of the first lateral surface sub-region along the cover surface, and in a further step either, the shrinkage direction (12) being changed approximately a further 90°, the heat-shrink film (4) is shrunk from top to bottom in the region of that lateral surface sub-region of the goods stack (2) which is located oppositely from the first lateral surface sub-region, or, the shrinkage direction (12) being changed approximately a further 90°, the heat-shrink film (4) is preheated from top to bottom in the region of that lateral surface sub-region of the goods stack (2) which is located oppositely from the first lateral surface sub-region, and is then shrunk in the opposite direction from bottom to top.

13. The apparatus according to claim 12, wherein at least one heating device (5) comprises different mutually independently controllable heating regions.

14. The apparatus according to claim 12, wherein at least one heating device (5) is embodied as a gas burner strip.

15. The apparatus according to claim 12, wherein that side of at least one heating device (5) which faces toward the goods stack (2) is embodied to be flat.

16. The apparatus as recited in claim 12, wherein at least one heating device (5) protrudes beyond the width of the goods stack (2), so that the heating device (5) projects beyond the goods stack (2) at least on one side, preferably on both sides, of the goods stack (2).

17. The apparatus according to claim 12, wherein at least one region, projecting laterally with respect to the goods stack (2), of at least one heating device (5) is arranged pointing toward the goods stack (2) at an angle.

18. The apparatus according to claim 16, wherein at least one region projecting laterally with respect to the goods stack (2) comprises at least one device for modifying the discharge direction of the hot air.

19. The apparatus according to claim 12, wherein at least one planar thermal conduction and/or thermal reflection device (7) is provided, which device: at least partly, preferably completely, covers the goods stack (2) at the top at least during shrinking of the first of the four lateral surface sub-regions; is arranged above the goods stack (2) at a distance from the cover surface; and is oriented parallel to the latter.

20. The apparatus according to claim 19, wherein at least one thermal conduction and/or thermal reflection device (7) is arranged vertically adjustably.

21. The apparatus according to claim 19, wherein at least one thermal conduction and/or thermal reflection device (7) completely covers the cover surface of the goods stack (2), or is embodied to be even bigger with an overhang.

22. The apparatus according to claim 19, wherein at least one thermal conduction and/or thermal reflection device (7) is equipped laterally, on its two lateral edges oriented parallel to the conveying direction (3), with a respective downward-pointing angled piece (8).

23. The apparatus according to claim 19, wherein at least one thermal conduction and/or thermal reflection device (7) is equipped, on its lateral edge oriented oppositely to the conveying direction (3), with a downward-pointing end-face angled piece (9).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Exemplifying embodiments of the invention, depicted in the drawings, will be explained below. In the drawings:

[0047] FIG. 1 is a side view of an apparatus according to the present invention;

[0048] FIG. 2 is a side view of a thermal conduction and/or thermal reflection device according to the present invention; and

[0049] FIGS. 3 to 9 illustrate execution of the method according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

[0050] In all the Figures, matching reference characters are used for identical or similar components.

[0051] FIG. 1 is a side view of an apparatus according to the present invention for shrinking. It comprises a conveying device 1 that is, for example, a conveyor belt. Placed on conveying device 1 is a goods stack 2 that can be displaced in conveying direction 3 by means of conveying device 1.

[0052] The rectangularly configured goods stack 2 has a cover surface, a lateral surface that is made up of four lateral surface sub-regions, and a bottom surface. Goods stack 2 has two oppositely located long sides that are oriented parallel to conveying device 3, and two oppositely located short sides. In the exemplifying embodiment depicted, goods stack 2 is not placed on a pallet. The shape of goods stack 2 is cuboidal.

[0053] As is evident from FIG. 1, the apparatus for impingement of heat onto a heat-shrink film 4 (not depicted in FIG. 1) that is applied around goods stack 2 comprises a heating device 5 that is embodied in oblong fashion and is oriented horizontally above conveying device 1 and orthogonally to conveying direction 3. The width of the heating region of heating device 5 is at least as great as the width of goods stack 2 in the region of the two short sides, so that the lengthwise dimension of heating device 5 extends at least over the width of goods stack 2. Heating device 5 is arranged vertically adjustably by way of an apparatus (not depicted), and is furthermore mounted pivotably around an axis 6 oriented parallel to its lengthwise dimension.

[0054] Also provided is a thermal conduction and/or thermal reflection device 7 that is likewise vertically adjustable and is configured, in the exemplifying embodiment depicted, as a heat accumulation panel. The heat accumulation panel is equipped laterally, on both lateral edges oriented parallel to conveying direction 3, with a respective downward-pointing angled piece 8. The spacing of the two angled pieces 8 is selected so that it is greater than the width of goods stack 2, so that goods stack 2 can thus be moved through between the two angled pieces 8. If goods stacks 2 of differing widths are to be shrunk, it is useful if the spacing of the two oppositely located angled pieces 8 is adjustable. With a configuration of this kind, preferably each angled piece 8 is displaceable horizontally and approximately orthogonally to conveying direction 3.

[0055] At its lateral edge pointing oppositely to conveying direction 3, thermal conduction and/or thermal reflection device 7 comprises an end-face angled piece 9, which likewise points downward but whose height is selected so that goods stack 2 can be moved through below end-face angled piece 9 without colliding. For vertical adjustment, thermal conduction and/or thermal reflection device 7 comprises two carriages 10 that are arranged vertically displaceably on two support poles (not depicted). Thermal conduction and/or thermal reflection device 7 is fastened via a retaining frame 11 onto carriages 10.

[0056] For better illustration of the method sequence, thermal conduction and/or thermal reflection device 7 is depicted only in very highly simplified fashion in FIGS. 3 to 9. Angled pieces 8 and carriages 10, for example, are not depicted. The apparatus comprises a suitable control system for carrying out the method described below.

[0057] FIG. 3 depicts the beginning of the shrinking process. Heat-shrink film 4, which is embodied in the exemplifying embodiment depicted as a heat-shrink film wrapper, has already been applied around goods stack 2 in an upstream apparatus. In the exemplifying embodiment depicted, heat-shrink film 4 covers the lateral surface of goods stack 2 over the entire height of the lateral surface. Heat-shrink film 4 projects at the top, with a circumferential heat-shrink film sub-region 4a, beyond the top edge of goods stack 2 for later formation of a top shrink. In addition, in this exemplifying embodiment a cover sheet film has been applied onto the cover surface of goods stack 2. Heat-shrink film sub-region 4a projecting at the top has already been folded over and rests on the cover sheet film.

[0058] As depicted in FIG. 3, at the beginning of the shrinking process heating device 5 is in its lowest position. Heating device 5 is activated so that hot air is blown onto the first of the four lateral surface sub-regions of goods stack 2. In the exemplifying embodiment depicted, this first lateral surface sub-region is the front side pointing in conveying direction 3. As is evident from FIG. 3, hot air is preferably blown onto goods stack 2 substantially horizontally or with a slightly obliquely downward orientation.

[0059] At this point in time, thermal conduction and/or thermal reflection device 7 is located above goods stack 2 and thus covers it completely. The hot air that rises as the first lateral surface sub-region is shrunk flows into the gap between the cover surface of goods stack 2 and thermal conduction and/or thermal reflection device 7, and enables preheating here of heat-shrink film sub-region 4a that projects at the top and of the cover sheet film. Heating device 5 is then moved upward in the direction of arrow 12 (shrinkage direction) until it has reached the position depicted in FIG. 4.

[0060] Goods stack 2 is then displaced by conveying device 1 in conveying direction 3. In order to shrink heat-shrink film sub-region 4a that projects at the top, and optionally also the cover sheet film, heating device 5 is pivoted around its lengthwise dimension until hot air is being blown approximately vertically downward, and in this manner that heat-shrink film sub-region 4a of heat-shrink film 4 which projects at the top beyond the top edge of goods stack 2, and optionally also the cover sheet film, are shrunk along the cover surface starting from the top edge of the first lateral surface sub-region to the top edge of that lateral surface sub-region which is located oppositely from the first lateral surface sub-region. Shrinkage direction 12 is parallel to the cover surface. For shrinking, goods stack 2 is moved continuously in conveying direction 3 until goods stack 2 has reached the position in FIG. 8. As a result of the displacement of goods stack 2, the proportion of the cover surface of goods stack 2 covered by thermal conduction and/or thermal reflection device 7 becomes increasingly small until, as is evident e.g. from FIG. 7, no further coverage at all is provided by thermal conduction and/or thermal reflection device 7.

[0061] As depicted in FIG. 8, shrinkage direction 12 changes again after the shrinking of heat-shrink film sub-region 4a of heat-shrink film 4 which projects at the top, and optionally also of the cover sheet film, since heating device 5 is now lowered vertically in order to shrink that lateral surface sub-region which is located oppositely from the first lateral surface sub-region. For this, heating device 5 is again pivoted around its lengthwise dimension so that heat-shrink film 4 can now be shrunk from top to bottom in the region of that lateral surface sub-region which is located oppositely from the first lateral surface sub-region. The shrinking process is completed in FIG. 9. As is evident from FIGS. 8 and 9, hot air is preferably blown onto goods stack 2 substantially horizontally or with a slightly obliquely downward orientation.

[0062] If heating device 5 projects beyond the width of goods stack 2, heating device 5 preferably projects beyond goods stack 2 on both sides of goods stack 2. By means of each projecting region, a narrow marginal region 13 of heat-shrink film 4 on the respective lateral surface sub-region oriented parallel to conveying direction 3 or parallel to shrinkage direction 12 during shrinking of the cover surface, which region adjoins the edge to the first lateral surface sub-region of goods stack 2 and/or adjoins the edge to the top side of goods stack 2 and/or adjoins the edge to that lateral surface sub-region of goods stack 2 which is located oppositely from the first lateral surface sub-region, can additionally be shrunk.

[0063] When the lateral surface sub-region oriented parallel to conveying direction 3 or parallel to shrinkage direction 12 during shrinking of the cover surface is shrunk in the three marginal regions 13 (vertically oriented lateral edge to the first lateral surface sub-region, and horizontally oriented top edge to the top side of goods stack 2, and vertically oriented lateral edge to that lateral surface sub-region which is located oppositely from the first lateral surface sub-region), the shrunken region of this lateral surface sub-region oriented parallel to conveying direction 3 or parallel to shrinkage direction 12 during shrinking of the cover surface is in the shape of an upside-down “U.” This U-shaped marginal region 13 is depicted with hatching exclusively in FIG. 9. The remaining area of this lateral surface sub-region remains unshrunk.

[0064] After completion of the shrinking process in FIG. 9, heating device 5 is pivoted approximately 180° around its lengthwise direction and the next, as-yet unshrunk, goods stack 2 is transported in by conveying device 1 for shrinking.