Work station for a packaging machine with a lifting mechanism with a toggle lever mechanism

Abstract

The work station for a packaging machine comprises an upper tool, a lower tool, and a lifting mechanism. The lower tool is guided for a closing motion directed along a vertical direction towards the upper tool. The lifting mechanism comprises a toggle lever mechanism which connects the lower tool to a support structure. The lifting mechanism comprises a first actuator assembly and a second actuator assembly. The first actuator assembly is configured to apply a first force for raising the lower tool. The second actuator assembly is configured to apply a second force for raising the lower tool. The first actuator assembly acts upon the lower tool while bypassing the toggle lever mechanism. The second actuator assembly acts upon the toggle lever mechanism.

Claims

1. A work station for a packaging machine, the work station comprising: an upper tool and a lower tool, where the lower tool is guided for a closing motion that is directed along a vertical direction towards the upper tool; and a lifting mechanism comprising a toggle lever mechanism connecting the lower tool to a support structure; wherein the lifting mechanism comprises a first actuator assembly configured to apply a first force for raising the lower tool and a second actuator assembly configured to apply a second force for raising the lower tool; and wherein the first actuator assembly acts upon the lower tool while bypassing the toggle lever mechanism and the second actuator assembly acts upon the toggle lever mechanism.

2. The work station according to claim 1, wherein the first actuator assembly is configured to raise the lower tool by a first stroke and the second actuator assembly is configured to raise the lower tool by a second stroke, wherein the first stroke is larger than the second stroke.

3. The work station according to claim 2, wherein the second actuator assembly is configured to be activated to apply the second force after the lower tool has been raised by the first actuator assembly.

4. The word station according to claim 1, wherein the first actuator assembly and the second actuator assembly are configured to apply the first force and the second force simultaneously for a period of time.

5. The work station according to claim 1, wherein the first actuator assembly raising the lower tool leads to an adjustment of the toggle lever mechanism without active operation of the second actuator assembly.

6. The work station according to claim 1, wherein the first actuator assembly raising the lower tool leads to an extension of the toggle lever mechanism.

7. The work station according to claim 1, wherein the second actuator assembly is configured to provide a pressing force for pressing the lower tool against the upper tool.

8. The work station according to claim 1, wherein the toggle lever mechanism comprises multiple toggle lever structures, each of the multiple toggle level structures connecting the lower tool to the support structure, wherein the second actuator assembly acts upon the multiple toggle lever structures.

9. The work station according to claim 8, wherein the second actuator assembly comprises an element variable in length that acts simultaneously upon two oppositely disposed toggle lever structures.

10. The work station according to claim 8, wherein the second actuator assembly comprises a pneumatic cylinder that acts simultaneously upon two oppositely disposed toggle lever structures.

11. The work station according to claim 1, wherein the first actuator assembly and/or the second actuator assembly comprises an element variable in length.

12. The work station according to claim 1, wherein the lower tool is suspended on rods.

13. The work station according to claim 12, wherein the first and/or the second actuator assembly is suspended on the rods.

14. The work station according to claim 1, wherein the first actuator assembly and/or the second actuator assembly comprises a pneumatic cylinder.

15. The work station according to claim 1, wherein the second actuator assembly is spaced from and not connected to the first actuator assembly.

16. The work station according to claim 1, wherein the first actuator and the second actuator assembly each comprise a pneumatic cylinder, a spindle drive, or an electric linear drive.

17. The work station according to claim 1, wherein the first actuator assembly and the second actuator assembly each comprise an element variable in length.

18. The work station according to claim 1, wherein the first actuator assembly and the second actuator assembly each comprise a drive.

19. A method for operating a work station for a packaging machine, the method comprising: raising a lower tool along a vertical direction towards an upper tool by applying a first force by way of a first actuator assembly which acts upon the lower tool while bypassing a toggle lever mechanism which connects the lower tool to a support structure; applying a second force for pressing the lower tool against the upper tool by way of a second actuator assembly which acts upon the toggle lever assembly.

20. The method according to claim 19, wherein raising the lower tool by way of the first actuator assembly adjusts the toggle lever assembly.

21. The method according to claim 19, wherein the toggle lever assembly is first adjusted by raising the lower tool by way of the first actuator assembly to a work range with improved leverage and the second actuator assembly subsequently actively actuates the toggle lever assembly to further raise the lower tool and/or to press the lower tool against the upper tool.

22. The method according to claim 19, wherein the first force is also applied, during the application of the second force.

23. A work station for a packaging machine, the work station comprising: an upper tool and a lower tool, the lower tool being guidable in a closing motion along a vertical direction towards the upper tool; and a lifter comprising a toggle lever connecting the lower tool to a support structure; the lifter comprising a first actuator configured to apply a first force for raising the lower tool and a second actuator configured to apply a second force for raising the lower tool; and wherein the first actuator is actable upon the lower tool while bypassing the toggle lever and the second actuator is actable upon the toggle lever.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The disclosure shall be illustrated below in more detail using embodiments, where

(2) FIG. 1 shows a schematic side view of a packaging machine with a work station according to an embodiment;

(3) FIG. 2 shows a schematic perspective view of a work station according to an embodiment in the open state of the work station;

(4) FIG. 3 shows a further schematic perspective view of a work station in the open state of the work station;

(5) FIG. 4 shows a schematic side view of the work station in the open state of the work station;

(6) FIG. 5 shows a schematic perspective view of the work station in the closed state of the work station; and

(7) FIG. 6 shows a schematic side view of the work station in the closed state of the work station.

DETAILED DESCRIPTION

(8) FIG. 1 shows an exemplary packaging machine 1 in which a work station 3 according to the disclosure may be employed. In the embodiment shown, packaging machine 1 is configured as a deep-drawing packaging machine. Packaging machine 1 comprises a machine frame 5 on which a forming station 7, a sealing station 9, and a cutting station 11 are arranged. Packaging machine 1 comprises a conveyor device 13 for conveying a base film web 15 along a direction of transport T. Base film web 15 is fed consecutively to forming station 7, to a loading stretch 17 located between forming station 7 and sealing station 9, to sealing station 9, and to cutting station 11.

(9) In forming station 7, packaging trays are formed in base film web 15 by deep drawing. Forming station 7 comprises a forming tool upper part 7a and a forming tool lower part 7b which is movable relative to the former, both of which interact to deep-draw the packaging trays in base film web 15. The packaging trays formed in base film web 15 are filled in loading stretch 17 with products to be packaged. The filled packagings are closed in sealing station 9 by sealing a top film 19 onto base film 15. Scaling station 9 comprises a sealing tool upper part 9a and a sealing tool lower part 9b which is movable relative to the former, both of which interact to close the packaging trays with top film 19. The closed packages are separated from the film composite in cutting station 11. Cutting station 11 comprises a cutting tool upper part 11a and a cutting tool lower part 11b movable relative to the former. Cutting tool upper part 11a and cutting tool lower part 11b interact to separate the packagings from the film composite.

(10) The disclosure relates to a work station 3 for a packaging machine 1. Work station 3 can be, for example, forming station 7, sealing station 9 or cutting station 11 of a deep-drawing packaging machine. It would also be conceivable, however, that work station 3 is employed in a packaging machine 1 of a different kind, for example, in a tray sealer.

(11) Work station 3 comprises an upper tool 21 and a lower tool 23. Examples of upper tool 21 in packaging machine 1 described above are forming tool upper part 7a, sealing tool upper part 9a, or cutting tool upper part 11a. Examples of lower tool 23 in packaging machine 1 described above are forming tool lower part 7b, sealing tool lower part 9b, or cutting tool lower part 11b.

(12) FIG. 2 shows a schematic perspective view of a work station 3 according to an embodiment. In the variant shown, the work station is a sealing station 9. The configuration described, however, may also be transferred to other work stations 3 by replacing upper tool 21 and lower tool 23 with differently configured tools.

(13) In the embodiment shown, upper tool 21 is attached to machine frame 5 in a stationary manner. This may be done, for example, using screw holes. Upper tool 21 in FIG. 2 may have coolant bores 25. Vertical rods 27 are attached to upper tool 21. Vertical rods 27 extend downwardly from upper tool 21. Rods 27 provide a vertical guide for lower tool 23. Lower tool 23 is guided along a vertical direction along rods 27 for a motion towards upper tool 21. In the embodiment shown, lower tool 23 comprises a working member 23a which interacts with upper tool 21 when lower tool 23 is raised along the vertical direction. In the embodiment shown, working member 23a of lower tool 23 comprises recesses for receiving packaging trays, at least in part. In a work cycle, lower tool 23 may first be approached to upper tool 21 along the vertical direction and then pressed thereagainst in order to provide a working pressure. It is understood that, when lower tool 23 is pressed against upper tool 21, one or more components may be present between lower tool 23 and upper tool 21. For example, in the case of a forming station 7, base film web 15 may be present between forming tool lower part 7b and forming tool upper part 7a, or, in the case of a sealing station 9, base film web 15 and top film 19 may be present between sealing tool lower part 9b and sealing tool upper part 9b.

(14) In the embodiment shown, lower tool 23 also comprises a support member 23b on which working member 23a is supported. In the embodiment shown, support member 23b of lower tool 23 comprises two parallel, horizontal carrier elements 29. Working member 23a of lower tool 23 may simply stand on support member 23b. Working member 23a may be firmly connected to support member 23b, for example, using screw connections. No articulate connection is provided between support member 23b and working member 23a of lower tool 23.

(15) Work station 3 comprises a lifting mechanism 31 for raising lower tool 23 and for applying the closing force for pressing lower tool 23 against upper tool 21 As can likely be seen best in FIG. 3, lifting mechanism 31 comprises a first actuator assembly 33 for applying a first force for raising lower tool 23. In the embodiment shown, first actuator assembly 33 comprises a first pneumatic cylinder 35, which engages with an intermediate plate 37 that is firmly connected to two carrier elements 29 of support member 23b of lower tool 23. In the embodiment shown, an extendable end of first pneumatic cylinder 35 is attached to intermediate plate 37. In the embodiment shown, first actuator assembly 33 therefore acts directly upon lower tool 23. In certain embodiments, it would also be conceivable that further connecting elements are interposed between lower tool 23 and first pneumatic cylinder 35. A stationary part of first pneumatic cylinder 35 is attached to a connection support 39 which is attached to two oppositely disposed vertical rods 27. First actuator assembly 33 is therefore suspended at upper tool 21 by vertical rods 27.

(16) As can likely be seen best from FIGS. 5 and 6, which show work station 3 in a closed position, i.e., with lower tool 23 raised, lifting mechanism 31 also comprises a toggle lever mechanism 41. Toggle lever mechanism 41 comprises multiple toggle lever structures 43. Individual toggle lever structures 43 are configured similarly to one another in the embodiment shown. In the embodiment shown, toggle lever mechanism 41 comprises four toggle lever structures 43, each of which is arranged a one of vertical rods 27. Toggle lever structures 43 each comprise a first lever 45 and a second lever 47. First lever 45 is connected to associated rod 27 in a manner rotatable about a horizontal axis. Second lever 47 is connected to lower tool 23 in a manner rotatable about a horizontal axis. In addition, first lever 45 and second lever 47 are connected to one another at a connection point 49 and rotatable about a horizontal axis.

(17) Lifting mechanism 31 also comprises a second actuator assembly 51 which comprises two second pneumatic cylinders 53 in the embodiment shown. Second pneumatic cylinders 53 each connect two oppositely disposed toggle lever structures 43. As can be seen from FIGS. 4 and 6, second pneumatic cylinders 53 are connected to associated toggle lever structures 43 in such a way that toggle lever structures 43 are erected when second pneumatic cylinders 53 are extended and a force for lifting lower tool 23 is thus generated. Retraction of the second pneumatic cylinder, i.e., shortening second pneumatic cylinder 53, on the other hand, may lead to toggle lever structures 43 folding together and lower tool 23 being lowered.

(18) First actuator assembly 33 acts upon lower tool 23 while bypassing toggle lever mechanism 41, as can be seen from FIG. 3. The action of force by first actuator assembly 33 upon lower tool 23 is therefore not effected via toggle lever mechanism 41. A transmission ratio of toggle lever mechanism 41 is not relevant for the transmission of force by first actuator assembly 33 upon lower tool 23. Second actuator assembly 51 acts upon toggle lever mechanism 41. Power transmission for raising lower tool 23 by second actuator assembly 51 is effected in accordance with the transmission ratio of toggle lever mechanism 41.

(19) If lower tool 23 is to be raised from the lowered position (open work station 3) shown in FIGS. 2, 3 and 4, then first actuator assembly 33 is first actuated to raise the lower tool 23. First pneumatic cylinder 35 is extended and raises lower tool 23. In this phase, second actuator assembly 51 is in a freewheeling mode. Second pneumatic cylinders 53 may therefore be extended or retracted essentially without resistance. When lower tool 23 is raised by first actuator assembly 33, toggle lever mechanism 41 is raised to a certain extent quasi as a positive side effect. By raising lower tool 23 by way of first actuator assembly 33, which acts upon lower tool 23 while bypassing toggle lever mechanism 41, toggle lever mechanism 41 is therefore put into a state in which there is an improved transmission ratio given when toggle lever mechanism 41 is actuated by second actuator assembly 51. Once lower tool 23 has been raised to a certain extent by first actuator assembly 33, then second actuator assembly 51 is activated and acts upon toggle lever mechanism 41 to further raise lower tool 23 or to press lower tool 23 against the upper tool 21. This is done specifically by extending second pneumatic cylinder 51 and a resulting transmission of force by toggle lever mechanism 41 upon lower tool 23. This procedure is particularly efficient because toggle lever mechanism 41 has already been taken to a work region with a good transmission ratio by first actuator assembly 33 prior to second actuator assembly 51 being activated

(20) First actuator assembly 33 may be dimensioned substantially such that it applies the force required for raising lower tool 23, i.e., may counteract at least the weight force of lower tool 23. The additional force for pressing lower tool 23 against upper tool 21 may be provided by second actuator assembly 51. Second pneumatic cylinders 53 of second actuator assembly 51 may be dimensioned to be relatively small due to the division of the force between first actuator assembly 33 and second actuator assembly 51 when lower tool 23 is pressed against upper tool 21 and due to the good transmission ratio in toggle lever mechanism 41.

(21) Lower tool 23, first actuator assembly 33 and second actuator assembly 51 are supported by vertical rods 27. The stroke of lower tool 23 may be adjusted in a simple manner by adjusting vertical rods 27 on upper tool 21.