DEVICE FOR WELDING TWO OVERLAPPING FILM SECTIONS SITUATED ON ONE SIDE OF A GOODS STACK, PREFERABLY ON THE UPPER SIDE OF A GOODS STACK, TO FORM A WRAPPING

Abstract

The invention is a device for welding two overlapping film sections situated on one side of a goods stack. The device includes a welding bar with a welding surface oriented in the direction of the film sections to be welded. The spacing between the welding bar and the film sections is reducible. The welding surface is elastically deformable into a concave course and/or to a convex course between its two ends. At least one displacing device adjusts the course of the welding surface to a concave and/or to a convex course. The displacing device displaces welding bar. A control unit of the welding bar individually controllable, such that the curvature of the welding bar is adjustable to the contour of the side of the goods stack in the region of the film sections to be welded with one another for the subsequent welding of the overlapping film sections.

Claims

1. Device for welding two overlapping film sections situated on a side of a goods stack (1), preferably on the upper side of a goods stack (1), to form a wrapping, where the device exhibits a welding bar (2) with a welding surface (3) oriented in the direction of the film sections to be welded, where the welding bar (2) exhibits a mounting (4, 5) at least in the region of each of its two ends and where for welding of the film sections the spacing between the welding bar (2) and the film sections to be welded is reducible all the way to contact, wherein at least the welding surface (3) of the welding bar (2) is configured as elastically deformable for adjusting the welding surface (3) to a concave course and/or to a convex course of the side of the goods stack (1) between its two ends and that there is assigned to the welding bar (2) between the two mountings (4, 5) at least one displacing device (9), preferably acting at least in the direction of the film sections to be welded, for adjusting the course of the welding surface (3) to a concave and/or to a convex course of the side of the goods stack (1) and that in at least one mounting (4, 5) and/or in at least one displacing device (9) the contact region with which the mounting (4, 5) and/or the displacing device (9) respectively acts on the welding bar (2) is displaceable along the welding bar (2) as seen in the longitudinal extension of the welding bar (2), and that for at least one displacing device (9), preferably for all displacing devices (9), the device comprises a control unit, wherein each displacing device (9) of the welding bar (2) is individually controllable, such that the curvature of the welding bar (2) for the subsequent welding of the overlapping film sections is adjustable to the contour of the side of the goods stack (1) in the region of the film sections to be welded with one another.

2. Device according claim 1, wherein the device further exhibits a goods stack displacing device, preferably a goods stack displacing device configured as a lifting device (6), for displacing the goods stack (1) in the direction of the welding bar (2) for welding.

3. Device according to claim 1, wherein at least one of the two mountings (4, 5), preferably both mountings (4, 5), is (are) configured as a displacing device (9) for displacing the welding bar (2) from its rest position wherein the welding bar (2) is arranged at a distance from the film sections to be welded, in the direction of the side of the goods stack (1) into its welding position wherein the welding bar (2) is in contact with the upper film section of the two overlapping film sections to be welded with one another, wherein for at least one displacing device (9), preferably for all displacing devices (9), the device comprises a control unit, wherein each displacing device (9) of the welding bar (2) is individually controllable, such that the curvature of the welding bar (2) is adjustable to the contour of the side of the goods stack (1) in the region of the film sections to be welded to one another for the subsequent welding of the overlapping film sections.

4. Device according to claim 1, wherein the welding bar (2) is configured as a flexible rail, preferably consisting of aluminum, with the welding surface (3) oriented in the direction of the film sections to be welded.

5. Device according to claim 1, wherein the welding surface (3) is configured as a welding wire.

6. Device according to claim 5, wherein the welding wire is stretched between the two ends of the welding bar (2), wherein the welding wire is guided along a pressure surface (13) oriented in the direction of the film sections to be welded.

7. Device according to claim 6, wherein the welding wire is insulated from the pressure surface (13) through an insulation layer (14).

8. Device according claim 1, wherein at least one mounting (4, 5) and/or at least one displacing device (9) is (are) arranged slidingly at a rail (11) for displacing the contact region with which the mounting (4, 5) and/or the displacing device (9) respectively acts on the welding bar (2).

9. Device according to claim 8, wherein at least one rail (11) exhibits an undercut groove (12) extending along the rail (11) and wherein the mounting (4, 5) and/or the displacing device (9) each exhibits at least one slot nut interacting with the groove (12) and guided in the groove (12).

10. Device according to claim 1, wherein at least one mounting (4, 5) and/or at least one displacing device (9) is (are) manually displaceable.

11. Device according to claim 1, wherein at least one mounting (4, 5) and/or at least one displacing device (9) is (are) displaceable in a motorized manner.

12. Device according to claim 1, wherein at least one displacing device (9) is configured as a gear rack.

13. Device according to claim 1, wherein at least one displacing device (9) is configured as a cylinder.

14. Device according to claim 13, wherein at least one cylinder is configured as a pneumatic cylinder.

15. Device according to claim 13, wherein at least one cylinder is configured as a hydraulic cylinder.

16. Device according to claim 2, wherein the welding bar (2) is configured as a flexible rail, preferably consisting of aluminum, with the welding surface (3) oriented in the direction of the film sections to be welded.

17. Device according to claim 3, wherein the welding bar (2) is configured as a flexible rail, preferably consisting of aluminum, with the welding surface (3) oriented in the direction of the film sections to be welded.

18. Device according to claim 2, wherein the welding surface (3) is configured as a welding wire.

19. Device according to claim 3, wherein the welding surface (3) is configured as a welding wire.

20. Device according to claim 4, wherein the welding surface (3) is configured as a welding wire.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In the following, embodiment examples of invention depicted in the drawings are elucidated. The drawings show:

[0028] FIG. 1A first embodiment example of a device according to the invention with a goods stack exhibiting a concave surface,

[0029] FIG. 2A first embodiment example of a device according to the invention with a goods stack exhibiting a convex surface,

[0030] FIG. 3A second embodiment example of a device according to the invention with a goods stack exhibiting a concave surface,

[0031] FIG. 4A second embodiment example of a device according to the invention with a goods stack exhibiting a convex surface,

[0032] FIG. 5A third embodiment example of a device according to the invention with a goods stack exhibiting a concave surface,

[0033] FIGS. 6a and b An oblique top view and a side view of a fourth embodiment example of a device according to the invention,

[0034] FIG. 7A side view of a welding bar attached to a rail,

[0035] FIG. 8 A section in the direction VIII-VIII through the object according to FIG. 7,

[0036] FIG. 9A side view of the welding bar according to FIG. 7 without rail,

[0037] FIG. 10 The detail X from FIG. 9,

[0038] FIG. 11 An exploded view of the welding bar according to FIG. 7 in side view without rail,

[0039] FIG. 12 An oblique view of the object according to FIG. 11, and

[0040] FIG. 13 The detail XIII from FIG. 12.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

[0041] In all drawings, consistent reference labels are used for similar or equal components.

[0042] The drawings depict different designs of devices for welding two overlapping film sections situated on a side of a goods stack 1 to form a wrapping.

[0043] The wrapping is not depicted in the drawings. Usually the wrapping consists of a cover sheet film which is placed on the upper side of a goods stack 1. Usually a film sleeve is then drawn around the goods stack 1, where film sleeve is configured as open at the top and bottom. The film sleeve forms a film overhang and overhangs the upper side of the goods stack 1. If the wrapping should for example offer protection against rain, then after the drawing around the film overhang is welded with the cover sheet film on the upper side.

[0044] The upper side of the goods stack 1 depicted in FIGS. 1, 3 and 5 exhibits a central hollow and is thereby configured concavely. In FIGS. 2 and 4 there is depicted a goods stack 1 with an upper side which is arched and thereby configured convexly.

[0045] In the embodiment example according to FIGS. 6a and 6b, the film sections are welded with one another on a longitudinal side of the goods stack 1. For this purpose the cover sheet film is larger than the upper side of the goods stack 1. Before the drawing over of the film sleeve, the overhanging margins of the cover sheet film are placed around the upper edge of the goods stack 1.

[0046] The device comprises a welding bar 2 with a welding surface 3 oriented in the direction of the film sections to be welded, where the welding bar 2 exhibits a mounting 4, 5 in the region of each of its two ends.

[0047] For the welding of the film sections to be welded, the spacing between the welding bar 2 and the film sections to be welded can be reduced all the way to contact. In the embodiment examples according to FIGS. 1 to 4, the welding bar 2 is lowered in the direction of the upper side of the goods stack 1 until the welding surface 3 of the welding bar 2 is in contact with the film sections to be welded of the goods stack 1.

[0048] In the design depicted in FIG. 5, the welding bar 3 is not vertically moveable. Therefore, the device further exhibits a goods stack displacing device configured as a lifting device 6 for displacing the goods stack 1 in the direction of the welding bar 2 for welding. For welding, the goods stack 1 is raised by means of the lifting device 6 until the goods stack 1 comes into contact with the welding surface 3 of the welding bar 2 in the region of its opposite upper edge.

[0049] In FIG. 6 there is depicted a design which is suitable for welding two film sections in the region of a side of the goods stack 1. In such a design, either the welding bar 2 is moved sideways against the goods stack 1. Alternatively or additionally, the welding bar 2 can also be arranged immovably and the goods stack 1 can for example be moved by means of a conveying device against the welding bar 2.

[0050] Each welding bar 2 exhibits in the region of each of its two ends a mounting 4, 5. In the design according to FIG. 5, each mounting 4, 5 is configured as a bearing arranged immovably. Each bearing exhibits a bolt 7 which is guided in an oblong hole 8 assigned to the welding bar 2. Thereby the welding bar 2 is mounted rotatably and slidingly at least to a small extent, such that the welding bar 2 can be flexed downward or upward.

[0051] For adjusting the course of the welding surface 3 to a concave and/or to a convex course of the side of the goods stack 1 between the two mountings 4, 5, in the design according to FIG. 5 there is provided a displacing device 9 acting in the direction of the film sections to be welded. The device comprises for the displacing device 9 a control unit, not shown, such that the displacing device 9 is individually controllable. Thereby the curvature of the welding bar 2 can be adjusted to the contour of the in this case concave upper side of the goods stack 1 in the region of the film sections to be welded with one another for the subsequent welding of the overlapping film sections.

[0052] In the designs according to FIGS. 1 to 4, the two mountings 4, 5 provided in the region of the two ends of the welding bar 2 are themselves also each configured as a displacing device 9, such that hereby the welding bar 2 can be moved from its rest position, in which the welding bar 2—as depicted in the drawings—is arranged at a distance from the film sections to be welded, in the direction of the upper side of the goods stack 1 into its welding position in which the welding bar 2 is in contact with the upper film section of the two overlapping film sections to be welded with one another. The device comprises also for these displacing devices 9 a control unit, where each displacing device 9 of the welding bar 2 is individually controllable, such that the curvature of the welding bar 2 is adjustable to the contour of the side of the goods stack 1 in the region of the film sections to be welded with one another for the subsequent welding of the overlapping film sections. In such a design, the goods stack 1 can for example remain set down on a chain conveyor during welding, since the welding bar 2 is moved up to the goods stack 1.

[0053] The embodiment examples according to FIGS. 1 and 2 on the one hand and according to FIGS. 3 and 4 on the other differ by the device according to FIGS. 1 and 2 exhibiting only in the region of the two ends of the welding bar 2 a displacing device 9 configured as a mounting 4, 5.

[0054] In the embodiment example according to FIGS. 3 and 4, there is provided in the middle a third displacing device 9 configured as a mounting, which in this respect engages centrally with the welding bar 2. In this embodiment example, the three displacing devices 9 configured as a mounting, which are each connected directly with the welding bar 2 via the bolt 7 and the oblong hole 8, constitute in this respect a base for lifting and for lowering the welding bar 2.

[0055] Both in the embodiment example according to FIGS. 1 and 2 and in the embodiment example according to FIGS. 3 and 4, there is assigned respectively between two adjacent displacing devices 9 configured as mounting 4, 5 a displacing device 9 acting in the direction of the film sections to be welded for adjusting the course of the welding surface 3 to a concave and/or to a convex course of the side of the goods stack 1. The device comprises for each displacing device 9 a control unit, such that each displacing device 9 of the welding bar 2 is individually controllable. The curvature of the welding bar 2 can thereby be adjusted to the contour of the side of the goods stack in the region of the film sections to be welded with one another for the subsequent welding of the overlapping film sections.

[0056] As can be gathered from FIGS. 1 to 4, there is provided both in the design according to FIGS. 1 and 2 and in the design according to FIGS. 3 and 4 a further displacing device 9 between two adjacent displacing devices 9 configured as mounting 4, 5. Each further displacing device 9 acts in the direction of the film sections to be welded and serves for adjusting the course of the welding surface 3 to a concave and/or to a convex course of the side, in this case the upper side, of the goods stack 1. In each further displacing device 9, the contact region with which this displacing device 9 acts on the welding bar 2 is displaceable along the welding bar 2 as seen in the longitudinal extension of the welding bar 2. The device comprises for each further displacing device 9 a control unit, where each further displacing device 9 of the welding bar 2 is individually controllable, such that the curvature of the welding bar 2 is adjustable to the contour of the side of the goods stack 1 in the region of the film sections to be welded with one another for the subsequent welding of the overlapping film sections. In particular, the design according to FIGS. 3 and 4 allows very good adjustment of the welding surface 3 to an upper side of a goods stack 1, even if the upper side exhibits convex and concave regions when seen in the longitudinal direction of the welding bar 2.

[0057] In the design depicted in FIG. 5, the goods stack 1 is lifted for welding by means of the lifting device 6, until the goods stack 1 comes into contact with the welding surface 3 of the welding bar 2 in the region of its opposite upper edge. The displacing device 9 is then activated, such that the welding bar 2 is pushed down in the region of its center in the direction of the upper side of the goods stack 1. Consequently, the welding surface 3 is adjusted to the concave course of the upper side of the goods stack 1 and thereby a good welding result is achieved along the entire length of the welding surface 3.

[0058] As indicated by the arrows 10, the displacing device 9 is horizontally moveable. Thereby the contact region, i.e. the place at which the displacing device 9 acts on the welding bar 2, can be displaced and adjusted along the course of the welding bar 2 as seen in the longitudinal extension of the welding bar 2. Thereby the device can be adjusted optimally to the respective course of the upper side of the goods stack 1.

[0059] As the drawings show, the direction of movement of each displacing device 9 is exclusively orthogonal to the orientation of the side of the goods stack 1 at which the film sections to be welded are situated. The displacement and welding process is elucidated using the example of FIGS. 1 and 2. In the design of the upper side of the goods stack 1 according to FIG. 1, the welding bar 2 is first lowered by the two displacing devices 9 configured as mounting 4, 5 until the welding bar 2 touches the two opposite edges of the goods stack 1. Further lowering of the two displacing devices 9 configured as mounting 4, 5 is not possible. At the center of the goods stack 1, however, the welding bar 2 is not yet in contact with the goods stack 1. Then the displacing device 9 arranged between the two mountings 4, 5 and acting in the direction of the film sections to be welded is activated. It pushes the welding bar 2 at the center downwards until the welding bar 2 here too touches the film section. In this position (welding position), the welding bar 2 is curved and follows the concave course of the upper side of the goods stack 1.

[0060] In the design of the upper side of the goods stack 1 according to FIG. 2, the welding bar 2 is once again lowered by the two displacing devices 9 configured as mounting 4, 5. During lowering, the welding bar 2 first comes into contact with the goods stack 1 at the center. Since in the region of the two mountings 4, 5 the welding bar 2 is not yet in contact with the upper side of the goods stack 1, the two displacing devices 9 configured as mounting 4, 5 displace the welding bar 2 further in the direction of movement, i.e. orthogonally to the orientation of the side of the goods stack 1 at which the film sections to be welded are situated. The lowering takes place until the welding bar 1 also touches the goods stack 1 in the region of the opposite edges. Through the lowering, the welding bar 1 has become arranged about the convexly configured upper side of the goods stack 1 and in this respect is abutting along its entire length. In this position (welding position), the welding bar 2 is curved and follows the convex course of the upper side of the goods stack 1. In this design of the upper side of the goods stack 1, the use of the displacing device 9 arranged between the two mountings 4, 5 and acting in the direction of the film sections to be welded is not absolutely necessary, if the contact pressure generated by the two displacing devices 9 configured as mounting 4, 5 is sufficiently large. Depending on the length of the welding bar 2, the contact pressure of the welding surface 3 on the film sections to be welded on the segment between two displacing devices 9 configured as mounting 4, 5 can be too low. Then the welding result can be improved if in a supplementary manner at least one displacing device 9 is arranged between two adjacent displacing devices 9 configured as mountings 4, 5 and acting in the direction of the film sections to be welded.

[0061] As can be gathered from FIGS. 7 and 8, the displacing device 9 is arranged slidingly at a rail 11. The rail 11 exhibits in the depicted embodiment example at each of its four sides at least one undercut groove 12 extending along the rail 11. In the groove 12 arranged on the right-hand side of the rail 11 there is guided at least one slot nut which is attached to a bracket 22. The displacing device 9 is attached to the bracket 22.

[0062] In the depicted design, the displacing device 9 can be slid manually in the rail 11 and thereby along the welding bar 2 in the direction of the longitudinal extension. The position of the displacing device 9 can thereby be adjusted to the contour of the goods stack 1. Since for example in FIG. 1 the deepest place of the hollow is located at the center of the upper side, the displacing device 9 is so oriented that the displacing device 9 is situated above the deepest place.

[0063] In the depicted embodiment examples, every displacing device 9 is configured as a cylinder. The cylinder can for example be a pneumatic cylinder or a hydraulic cylinder.

[0064] With reference to FIGS. 1 to 4 and 6 and 9 it may be noted that the displacing devices 9 configured as mountings 4, 5 are of course connected with the welding bar 2. Thus the displacing devices 9 exhibit at their free end a screw which is guided in the oblong hole 8 assigned to the welding bar 2. Referring for example to the design according to FIG. 1, the two displacing devices 9 configured as mountings 4, 5 can move the welding bar 2 up and down, whereas the displacing device 9 arranged in the middle can only push the welding bar 2 down.

[0065] The basic construction of the welding bar 2 is depicted in FIGS. 8 to 12. The welding bar 2 is configured as a flexible rail, preferably consisting of aluminum, with the welding surface 3 oriented in the direction of the film sections to be welded. Therefore in the present case, the welding bar 2 and thereby also the welding surface 3 is configured as elastically deformable for adjusting the welding surface 3 to a concave course and/or to a convex course of the side of the goods stack 1 between its two ends. The welding surface 3 is configured as a welding wire.

[0066] The welding wire is stretched between the two ends of the welding bar 2, where the welding wire is guided along a pressure surface 13 oriented in the direction of the film sections to be welded and insulated through an insulation layer 14 from the pressure surface 13. The pressure surface 13 and the insulation layer 14 can be configured in two parts. It is, however, also certainly possible for the pressure surface 13 itself to form the insulation layer 14. Then the pressure surface 13 can for example be configured as a silicone band. The silicone band serves to insulate the welding surface 3 from the welding bar 2.

[0067] In order to prevent the welding wire adhering to the film section to be welded, the welding wire is provided with a sheathing 23 serving as a protective layer. As can be gathered from FIG. 12, the sheathing 23 is configured as a U-shaped rail which after the mounting of the welding wire is fitted onto the welding bar 2. The sheathing can, however, also be configured alternatively as a PTFE adhesive tape. In such a design, the lower region of the welding bar 2 is covered with the PTFE adhesive tape.

[0068] As can be gathered in particular from the detail shown in FIG. 10, the rail of the welding bar 2 exhibits a small height such that the rail is easily elastically deformable and in this respect can adjust to the contour of the goods stack 1. The welding bar 2 exhibits the pressure surface 13 oriented in the direction of the film sections to be welded. The welding surface 3 is configured as a welding wire stretched between the two ends of the welding bar 1, which is guided along the pressure surface 13 and is insulated from the pressure surface 13 by the insulation layer 14. The insulation layer 14 is arranged between the welding surface 3 configured as a welding wire and the welding bar 2 and in the depicted embodiment example is configured as a trapezoidal silicone band. The underside of the insulation layer 14 forms at the same time the pressure surface 13.

[0069] On the outside there is mounted on each end of rail an end piece 15, which for example consists of a synthetic material. For stretching the welding wire there is provided at each end a tensioning element 16, which is arranged displaceably about a rotational axis 17. The rotational axis 17 is provided in the upper region of the end piece 15. In the lower region of the front face of the end piece 15 there is provided a recess into which a compression spring 18 is inserted. By means of this compression spring 18, the tensioning element 16 is pushed away in the lower region from the welding bar 2. The welding wire is attached to the tensioning element 16 by means of a clamping element 19, which in the depicted case is a small plate secured by two screws. Through the compression spring 18, each tensioning element 16 is pushed away from the welding bar 2 and thereby the welding wire stretched.

[0070] In the design for example according to FIG. 3, the free end of the displacing device 9 acting on the welding bar 2 further exhibits a rubber pressure piece 20 which is attached to the displacing device 9 by means of an extension element 21.