Sealing tool and method for sealing trays

Abstract

A sealing tool for a tray sealing machine, comprising an upper tool and a lower tool with a main body having a tray depression for receiving at least a part of a tray to be sealed, and a tray carrier, wherein a gas channel runs through the tray carrier. The sealing tool is characterized in that the tray carrier comprises a first plate with a first pressing surface and a second plate with a second pressing surface and the first plate has a first depression which extends from the first pressing surface, wherein the first depression forms at least a section of the gas channel when the first plate and the second plate are pressed against each other at the first and the second pressing surface, respectively.

Claims

1. A sealing tool for a tray sealing machine, the sealing tool comprising: an upper tool; and a lower tool with a main body, which has a tray depression for receiving at least a part of a tray to be sealed, and with a tray carrier, wherein a gas channel runs through the tray carrier; wherein the tray carrier comprises a first plate with a first pressing surface and a second plate with a second pressing surface, wherein the first plate further has a first depression extending from the first pressing surface, wherein the first depression forms at least a section of the gas channel when the first plate and the second plate are pressed against each other at the first pressing surface and the second pressing surface, respectively, and wherein a protrusion is provided on the second pressing surface, and the protrusion is configured to extend into the first depression when the first plate and the second plate are pressed against each other.

2. The sealing tool according to claim 1, wherein the main body and the second plate are connected to each other in an unmovable manner during operation of the sealing tool.

3. The sealing tool according to claim 1, wherein the first plate is connected to the second plate during operation of the sealing tool, so that the first plate and the second plate are arranged unmovable relative to each other.

4. The sealing tool according to claim 1, wherein, when the first plate and the second plate are pressed against each other, the first depression together with the protrusion forms a funnel-shaped end section of the gas channel.

5. The sealing tool according to claim 1, wherein the second plate comprises a second depression extending from the second pressing surface, and wherein, when the first plate and the second plate are pressed against each other, the first depression and the second depression together form a section of the gas channel.

6. A method for evacuating and/or gas-flushing and sealing packaging trays by a sealing tool, which comprises an upper tool and a lower tool, wherein the lower tool includes a main body and a tray carrier, which includes a first plate and a second plate, the method comprising: inserting a packaging tray into the second plate of the tray carrier, wherein the second plate comprises a second pressing surface; closing the sealing tool by pressing the upper tool and the lower tool against each other; pressing the second plate of the tray carrier against the first plate, so that the second pressing surface and a first pressing surface provided on the first plate bear against each other, thereby forming at least a section of a gas channel for evacuating and/or gas-flushing the packaging tray; evacuating and/or gas-flushing the packaging tray; and sealing the tray with a top film; wherein the first plate further has a first depression extending from the first pressing surface, a protrusion is provided on the second pressing surface, and the protrusion is configured to extend into the first depression when the second plate is pressed against the first plate.

7. The method according to claim 6, further comprising clamping the top film onto the upper tool by the first plate before closing the sealing tool.

8. The method according to claim 6, wherein pressing the first plate against the second plate occurs while the sealing tool closes.

9. The method according to claim 6, wherein pressing the first plate against the second plate occurs before the sealing tool is closed.

10. The method according to claim 6, wherein the first depression forms the at least a section of the gas channel when the second plate is pressed against the first plate.

11. The method according to claim 6, wherein the main body and the second plate are connected to each other in an unmovable manner during operation of the sealing tool.

12. The method according to claim 6, wherein the first plate is connected to the second plate during operation of the sealing tool, so that the first plate and the second plate are arranged unmovable relative to each other.

13. The method according to claim 6, wherein, when the second plate is pressed against the first plate, the first depression together with the protrusion forms a funnel-shaped end section of the gas channel.

14. The method according to claim 6, wherein the second plate comprises a second depression extending from the second pressing surface, and wherein, when the second plate is pressed against the first plate, the first depression and the second depression together form a section of the gas channel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The disclosure relates to a sealing tool as well as to a method of the type described above. In the following, an embodiment of the disclosure is further illustrated with reference to drawings.

(2) FIG. 1 shows a schematic perspective view of a packaging machine;

(3) FIG. 2 shows a schematic perspective view of a sealing tool in an open state;

(4) FIG. 3 shows a schematic perspective view off sealing tool in a closed state;

(5) FIG. 4 shows a schematic perspective view of a tray carrier which comprises a first plate and a second plate which can be seen in the state pressed against each other;

(6) FIG. 5 shows a schematic perspective view of the first plate of the tray carrier with a view onto the first pressing surface;

(7) FIG. 6 shows a schematic perspective view of the second plate of the tray carrier with a view onto the second pressing surface; and

(8) FIG. 7 shows a schematic sectional view from the perspective indicated at VII-VII in FIG. 4.

DETAILED DESCRIPTION

(9) FIG. 1 shows an example of a packaging machine 1. It is a tray sealing machine. Packaging machine 1 may have a feed belt 7. It may furthermore have a sealing station 9. Trays 8 that are filled but at this time not yet sealed may be transported to sealing station 9 by feed belt 7. Trays 8 may be relocated with a gripper device 11 into sealing station 9 and there sealed with a top film 5 (film) supplied from above, for example, by sealing top film 5 thereonto. For this purpose, sealing station 9 may comprise a sealing tool 10 which shall be described later in more detail. The packagings thus completed may be relocated by gripper device 11 from sealing station 9 to a discharge belt 15.

(10) After sealing top film 5 thereonto, regions of top film 5 corresponding to the packagings or packaging assemblies may be cut out of the web of top film 5 in sealing station 9. There remains a film lattice of top film 5 which is wound by a device 3 for winding film 5.

(11) Sealing tool 10 can be seen in a perspective view in FIG. 2. As in the embodiment shown, sealing tool 10 may comprise an upper tool 12 and a lower tool 13. They may be moved towards each other in a closing direction S in order to close sealing tool 10. Lower tool 13 may contain a main body 14, as shown in the figure. It may be mounted, for example, onto a lifting unit 6 (not shown), which may be configured to move lower tool 13 towards upper tool 12 in closing direction S. Lower tool 13 may further have a tray carrier 16 (see FIG. 4). As can be seen in the figure, the latter may be provided on the side of main body 14 that faces towards upper tool 12.

(12) Tray carrier 16 may comprise a first plate 17 and a second plate 18. Even if in FIG. 2, first plate 17 is shown closer to upper tool 12 than to the other components of lower tool 13, it (first plate 17) is, due to its function, to be regarded as part of lower tool 13. A tray depression 19 may be provided in main body 14 and may be configured to accommodate at least part of tray 8 to be sealed.

(13) First plate 17 may have a first pressing surface 20 (see FIG. 5). Second plate 18 may have a second pressing surface 21. First plate 17 and second plate 18 may be pressed against each other at first pressing surface 20 and second pressing surface 21, thus forming tray carrier 16. This shall be explained in more detail with reference to FIGS. 4-6.

(14) Attachment devices 22 can be seen in FIG. 2. As shown in the present embodiment, they may be configured to connect second plate 18 to main body 14 in such a way that, during the operation of sealing tool 10, main body 14 and second plate 18 are arranged unmovable relative to each other. The person skilled in the art recognizes that in other embodiments than the one shown, attachment devices 22 may be adapted to connect also first plate 17 to main body 14 and second plate 18 in such a way that first and second plates 17, 18 as well as main body 14 are connected to each other in such a way that they are arranged unmovable relative to each other during the operation of sealing tool 10. FIG. 3 shows sealing tool 10 in a closed state.

(15) In FIG. 4, tray carrier 16 is shown in a perspective view as a separate assembly containing first plate 17 and second plate 18. Tray carrier 16 may have tray openings 23. They may form a lower part of a sealing chamber, for example, together with tray depressions 19 in the main body of the lower tool. Tray carrier 16 may further have a support edge 24. Such may each be provided circumferentially around one of tray openings 23. For inserting trays 8 into tray carrier 16, a flange provided on tray 8 may be placed on support edge 24. Support edge 24 may serve as an abutment for a sealing plate. As shall be explained in more detail later with reference to FIG. 7, tray carrier 16 may have gas-flushing and or evacuation openings 25 (see FIG. 7).

(16) FIG. 5 illustrates a perspective view of the first plate. Compared to the illustration in FIG. 4, first plate 17 is rotated by 180° about an axis running parallel to the longer side of tray carrier 16. This makes first pressing surface 20 visible. Also, a first depression 26 can now be seen which may be provided in first plate 17. It may extend in particular from first pressing surface 20, preferably in a direction perpendicular to the first pressing surface. In the first pressing surface, a groove 27 may additionally be provided into which a seal may be placed.

(17) Different types of first depressions 26 having different shapes may be provided. As in the present embodiment, for example, a first evacuation depression 26a may be provided. In addition, a first gas-flushing depression 26b may be provided. As already indicated by the designation, in the state of tray carrier 16 shown in FIG. 4, the former may form a section of an evacuation channel, while the latter may, in the state of tray carrier 16 shown in FIG. 4, form a section of a gas-flushing channel.

(18) FIG. 6 shows second plate 18. Compared to FIG. 4, missing first plate 17 exposes second pressing surface 21. As shown in FIG. 6, a protrusion 28 may be provided on second pressing surface 21. In the state of tray carrier 16 shown in FIG. 4, the protrusion 28 may be configured to extend into the first depression, in particular into first gas-flushing depression 26b. Furthermore, a second depression 29 may be provided which may extend from second pressing surface 21. It can also be seen that second plate 18 may have evacuation holes 30. They may be adapted to connect first depression 26 to the lower part of the sealing chamber in the state shown in FIG. 4. It may thus be prevented, in particular, that tray 8 received in tray carrier 16 deforms undesirably during the evacuation.

(19) FIG. 7 shows a sectional view of tray carrier 16 in the state shown in FIG. 4. Now it can be seen that first depression 26 may form a section 31 of a gas channel 32, when first plate 17 and second plate 18 are pressed against each other at first and second pressing surface 20, 21, respectively. As in the present embodiment, section 31 may be an end section 31 of gas channel 32. However, any section of the gas channel may be formed by first depression 26. In particular, end section 31 may be an inlet or an outlet through which gas may be introduced into or discharged from gas channel 32. Even if the facts were illustrated figuratively on the basis of first gas-flushing depression 26b with reference to FIG. 7, a person skilled in the art recognizes that the explanations are also transferable to first evacuation depression 26a.